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Day: 12 November 2024
Time: 10:45 - 12:00 h

Regulation and intensification of mass-transfer and separation processes with micro-/nano-structured functional materials

Prof. L.-Y. Chu*, Membrane Science and Functional Materials Group – Sichuan University, China

Mass transfer and separation processes are important processes in many industrial fields such as chemical engineering, biomedicine and so on. The regulation and intensification of mass transfer and separation processes play a key role in the transformation of traditional technology and the development of new technology.

By introducing the response behaviors of smart materials, it is possible to achieve the environmental regulation and intensification of mass transfer and separation processes, and it is one of the frontiers and hotspots in the interdisciplinary researches of chemical engineering and materials, chemistry, medicine and so on. How to construct novel mass-transfer and separation systems to break through the diffusion theory and enhance the membrane separation processes is still challenging in this field. B

y designing molecular-level structures and micro-/nano-structures,[1-5] we constructed responsive controlled release systems and smart membrane systems with smart materials, and pioneered the development of novel efficient smart membrane separation systems, responsive self-regulatory controlled release drug carriers with novel modes with the assistance of responsive smart materials.

Thus, the difficult problems of molecular desorption in affinity membrane separations and the limited mass transfer momentum in carrier systems have been successfully solved, and the regulation and intensification of mass transfer and separation processes have been achieved. The results provide novel strategies for the regulation and intensification of mass transfer and separation processes for various applications.

This presentation will introduce the recent development of stimuli-responsive smart functional membranes, including the design strategies and the fabrication strategies that based on introduction of the stimuli-responsive gates after or during membrane formation, the responsive models of versatile stimuli-responsive smart functional membranes, as well as the advanced applications of smart functional membranes for separating chemical/biological substances based on size or affinity, regulating substance concentration in reactors, and controlling release rate of drugs.

With the self-regulated membrane performances, smart functional membranes show great power for global sustainable development.

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12:00h - Lunch


K01 - Keynote Lecture 01

Day: 12 November 2024
Time: 13:00 - 14:15 h
Room 1

Membrane technology – New developments, challenges, markets and applications

Prof. S. Schütz*, Stuttgart University IMVT & MANN+HUMMEL, Germany

During the last decades membrane technology has become a key technology in filtration and separation applications. The global water economics and mainly the global drinking water supply is based on efficient membrane processes to ensure clean water for consumption. Industrial separation processes in the food & beverage segment, in chemical processing and in all fields of biotechnology rely upon membrane technology as membrane processes treat value products and molecules with high care compared to other separation technologies. The global transformation to green energy resources requiring new energy supply and storage systems like fuel cells, electrolysis and new battery concepts depends on innovative membrane technology.

This presentation will provide an overview about latest innovations and new applications in membrane technology and about future potentials for enhanced membrane products. New membrane materials and material combinations are enhancing membrane applications with higher efficiency on the one hand and with increased separation selectivity on the other hand compared to current state-of-the-art. Specifically modified membranes become highly selective for separation of single target molecules. Modern coating technologies and multi-component material recipes will enable enhanced membrane applications with high operational robustness and attractive economic potential soon. A lot of these innovations are currently driven by start-ups, which offer an enormous innovation potential for transfer and exploitation into industrial scale.

Apart from increased membrane performance and robustness, sustainability aspects play a significant role in membrane innovations. The term “sustainability” refers to future-oriented membrane applications as well as to membranes produced from sustainable, green materials. New environmentally friendly solvents and polymers offer enhanced market potentials for membranes. The ongoing discussions about PFAS molecules contaminating water are pushing these developments. This is especially valid with respect to ion exchange membranes for energy-related applications.

Additionally to the membrane media themselves, the design of membrane modules is a key aspect for safe and economic membrane processes. New types of membrane modules allow a flexible operation and high cleaning efficiencies. Membranes themselves can be specifically designed for an easy integration into modules considering specific application conditions and providing guarantee for long-term operation.

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G01 - Adsorption I

Day: 12 November 2024
Time: 13:00 - 14:15 h
Room 3

Simulation of adsorption-based processes to remove contaminants

A. Weber, P. Eichheimer, A. Wiegmann*, Math2Market GmbH, Germany

Adsorption-based processes play a crucial role in reducing environmental pollution and eliminating harmful substances. Common filter media materials, like activated carbon, zeolites, and metal-organic frameworks, are used to effectively purify fluids and gases for applications ranging from water treatment to air purification. A way to measure and classify the quality of adsorption filter media is to look at breakthrough curves. A breakthrough curve shows the concentration of the adsorbate in the filtrate behind the filter media, and breakthrough occurs in the moment when adsorbate reaches shows up in the filtrate.

In carbon capture, adsorption is vital to trap and store CO2 emissions from industrial activities and power generation, preventing their release into the atmosphere. The CO2 may be stored or used in processes like enhanced oil recovery or synthetic fuel production. However, determining breakthrough curves for a specific contaminant often requires time-consuming and costly experimental procedures.

In this context, the use of simulations allows to precisely control experimental parameters such as temperature, pressure, and surface properties to investigate their effects on adsorption behavior – gaining important insights into the microstructure to develop next-generation filter media.

In this study, we introduce the efficient simulation of adsorption on the filter media scale using GeoDict, a powerful tool for digital material development and prototyping. The approach is to calculate the molecular movement of particles and to solve for the adsorption equilibrium step by step using Langmuir and Toth adsorption isotherms. The simulation delivers breakthrough curves for arbitrary contaminants. The method is validated against experimental data from Coker and Knox, 2014 [1].

Future developments seek to include additional adsorption isotherms and improve simulation speed. Overall, these new simulation features provide new capabilities for product development in the field of adsorption-based filtration applications.

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Optimization of volatile organic compounds capturing capacity & life-time of activated carbon filters for air purification

I.S. Akgün Güldür*, A. Tüter, G. Sir, BEKO A.Ş., Turkey

Volatile organic compounds (VOCs) released while cooking contribute to harmful chemicals in the air, which can negatively impact air quality, the environment, and human health. Activated carbon filters are generally used in hoods and hob extractors to filter VOCs and provide fresh air inside the room. In this study, both life-time and VOC capturing capacity of nine non-regenerative and regenerative activated carbon filters were explored in the Hob-extractors which is a downdraft hood and operates by pulling air down and venting it to outside through ducts. Moreover, effects of amount of activated carbon inside the filters, types of filters as sponge, pleated and ceramic and surface area of activated carbons on both life-time and VOC capturing capacity were investigated. For non-regenerative filters, increasing surface area of activated carbon resulted in an increase in VOC capturing capacity whereas capturing capacity increased with increasing carbon amount until a certain value. Similar trend was observed for life-time of the non-regenerative filters. Both capturing capacity and the life-time of the non-regenerative filters mainly depended on surface area rather than amount of carbon inside the filter. On the other hand, both VOC capturing capacity and life-time of regenerative filters increased with decreasing surface area while increasing amount of activated carbon led to an increase in VOC capturing capacity and life-time of regenerative filters. The highest VOC capturing capacity was obtained with...

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See it. Control it. Defining the environment before deploying a filtration solution

J. M. Lobert*, Entegris Inc., USA

Filtration solutions are often deployed without accurately understanding the contamination challenges of the environment to be protected. This is usually done to either implement a solution as quickly as possible, or to minimize cost by using pre-defined and readily available off-the-shelf solutions. However, this approach neither assures an efficient contaminant removal nor does it optimize cost of ownership. An inexpensive filter changed out often may be more expensive than getting a tailored, more expensive solution that lasts much longer.

The approach promoted here is the See it. Control it. paradigm, where “seeing” means measuring the contamination first in order to characterize the environment, and “controlling” means implementing a filter solution that is tailored to that specific environment. Instead of formulating a filter solution that provides equal amounts of adsorbents for different contaminant classes, we suggest adjusting the adsor­­bents such that they match the actual environmental challenge, as determined by accurate measure­ments (Figure).

Contamination control concepts detailed in this paper are specifically for filters removing gas-phase air contami­na­tion and particles, but apply equally to any other type of filtration, such as the purification of liquids, solids or slurries.

To arrive at the best characterization of the environments to be protected, an accurate and specific measurement technique needs to be applied. For gas-phase evaluation, qualitative or semi-quantitative methods are unsuitable to do so (e.g., corrosion strips or micro balances).

To measure actual concentrations as well as contaminant identification, ISO 17025 accredited lab services should be used, which are found competent for specific analyses of spe­cific environments for specified concentration ranges. Such gas-phase contaminant concentrations can range from 100s of parts per million in odor problems to single digit parts per trillion in cleanroom environments as per ISO standard 14644-8. For particle contamination, the ...

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G02 - Filter Test

Day: 12 November 2024
Time: 13:00 - 14:15 h
Room 4

The classification of adsorptive HVAC filters according to ISO 10121-3 - Challenges and benefits

U. Sager*, E. Däuber, U. Schneiderwind, C. Asbach, Institute of Energy and Environmental Technology e.V. (IUTA); M. Wist, F. Schmidt, University Duisburg-Essen (UDE), Germany

In recent years, there has been an increasing demand for HVAC filters with adsorptive effect resulting in the standardization of a test method for these filters and filter media in ISO 10121, Parts 1 and 2. In 2022, Part 3 of ISO 10121 also introduced a classification system for adsorptive HVAC filters. This classification of adsorptive filters is based on the results of breakthrough tests with 9 ppm toluene, SO2, NO2 or 3 ppm ozone on the test filters. The filters are classified according to how long the filter separates the supplied test gas with an efficiency of at least 50 %. Following the evaluation of parts 1 and 2 of ISO 10121 in previous research projects, the project reported here focuses on the third part of the standard.

An overview is provided how the results of the standard breakthrough tests are used to determine the classification result. The individual classification parameters, performance class or duty level, integrated removal efficiency, initial removal efficiency and retention capacity are presented and the practical significance of the classification parameters is explained for various filter designs (compact filters, pocket filters, filter cartridges). In addition, the challenges involved in the practical implementation of the classification tests are shown with several examples.

One of the main challenges turned out to be the practical implementation of the tests with ozone. The provision of 3 ppm ozone with air flow rates of typically up to 3400 m³/h requires high-performance ozone generators. Another difficulty is the long test duration for ozone tests which is caused by the following reason: To obtain the performance class, the filtration efficiency for the specified test gas is considered as a function of the amount of test gas added (dose) per cross section of the filter. In this way, also filters with different nominal volume flow rates and installation cross-sections can be compared with each other. The performance class is determined by the dose at which the filter efficiency falls below 50 % during the breakthrough test. ISO 10121-3 specifies dose limits that classify the filter as Light Duty (LD), Medium Duty (MD) or Heavy Duty (HD). The molar dose limits are the same for all four test substances. Since the standard specifies a three times lower test gas concentration for ozone as for the other test gases the duration of the filter test with ozone is correspondingly longer. The test times for filters with a high ozone separation efficiency and/or low volume flow rates can by far exceed one working day, which is difficult to realize due to the special safety requirements for handling ozone.

In summary, the evaluation of the pure realization of the classification procedure and the basic practicability of the tests according to ISO 10121-3 has led to a positive result. The benefits of the classification are unquestioned; for the first time it is possible to compare the performance of adsorptive filters with different geometries and nominal volume flow rates. However, the test procedure on filters is quite complex and expensive because of the required test facility dimensions, large air volumes which have to be conditioned and large quantities of test substances that have to be provided. For this reason, it was also investigated to what extent and under what conditions the tests on media samples from filters lead to comparable classifications as the tests on filter elements. The results on the significance of determining the flow rate through the media sample during the test and the reference area for calculating the area-specific dose are discussed.

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Essential filter material test according IEC 60335-2-69 ANNEX AA using a gravimetric test method

D. Keßlau*, R. Heidenreich, E. Schmieder, Institute of Air Handling and Refrigeration (ILK), Germany

As part of the health protection of employees, occupational exposure limits are set for hazardous substances, which must be complied with by the operators of plants and companies. These regulations can be achieved by a near-source capture of the emissions and a separation of the hazardous substances by industrial vacuum cleaners and dust extractors that are equipped with filter elements made of highly efficient filter materials. These materials must be tested regarding their penetration rate in accordance with IEC 60335-2-69 annex AA. The test method described within this standard uses a photometer or a suitable measuring system to determine the concentrations used to evaluate the separation efficiency. The traceability of a photometer within the scope of accreditation is difficult to implement. For this reason, a test stand using a gravimetric measuring method was established at the Institut für Luft- und Kältetechnik in Dresden. Investigations into the limit of quantification have shown, that this measuring method is sensitive enough to reliably determine the dust classes “L” and “M”. Difficulties, limitations and new developments concerning the essential filter material test will be discussed.

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Ageing of fine fiber polypropylene melt blown in various conditions

C. Desquilles*, Alkegen, France

We have studied the effect of ageing on the efficiency of fine fiber Melt Blown.

Two grades have been selected for this study: One grade ePM1 75% and another one use in masks with BFE efficiency 98%.

These grades have been stored during 3 years in different shapes (rolls and A4 sheets) in different environments. The two environments are standard conditions (heated warehouse) and extreme conditions (in a trailer protected from weather but exposed to a large span of temperature and relative humidity).

Temperature and relative humidity have been recorded during the study. Mechanical properties and filtration properties have been measured regularly during the ageing. Whatever the conditions of storage and the shape of the samples, level of efficiency remains close to its initial value and remain well above the minimum efficiency obtained when exposing the samples to Isopropyl Alcohol vapor for 24 hours (discharge method used in ISO 16890).

This stability can be explained by....

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L01 - Challenges for Improving Sustainability of Filtration Processes

Day: 12 November 2024
Time: 13:00 - 14:15 h
Room 2

Filtration as a service as a way to make filtration more sustainable

M. Van Hooreweder*, HALLBAR, Belgium

This paper applies the concept of "Product as a Service" (PaaS) to the filtration industry. The traditional filtration business model does not sufficiently incentive manufacturers of filters to reduce energy consumption, CO2 emissions and waste generation in the downstream of their value chain.

Filtration as a Service (FaaS) offers a transformative approach by shifting from product-based to service-based models, thereby enabling more efficient resource utilization and reducing ecological footprints.

We focus on two key performance indicators (KPIs): (1) generated waste and (2) CO2 emissions, to evaluate the environmental benefits of FaaS. Through a comprehensive analysis, we compare conventional filtration systems with FaaS implementations with a focus on hydraulic filtration applications. The study reveals that FaaS can substantially lower the volume of waste produced by optimizing filter usage, maintenance, and disposal processes. Additionally, the service model fosters more efficient energy consumption and logistics, leading to a reduction in CO2 emissions.

Our findings indicate that adopting FaaS not only supports the sustainability goals of organizations but also contributes to broader environmental objectives by mitigating pollution and conserving resources. This paper provides actionable insights and strategic recommendations for businesses aiming to transition towards more sustainable filtration solutions.

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Vortex technology: A biometric revolution in filtration technology

M. Knefel*, GKD Group, Germany

Through biomimetic inspiration, GKD - Gebr. Kufferath AG has succeeded in developing a vortex separation unit that redefines filtration technology in terms of efficiency and sustainability. This article highlights the technological principles and the versatile application possibilities of the patented unit, which uses vortex flows to which optimizes particle separation.

The development of innovative filtration technologies that guarantee both economic efficiency and ecological sustainability is at the heart of current research and development in the field of process technology. An outstanding example of example of such progress is GKD's patented vortex separation unit, which represents a significant paradigm shift in particle separation.

Through the innovative application of vortex flows, this technology enables a revolutionary improvement in particle separation that is both technically advanced and in line with the principles of sustainability. This technical article highlights the biomimetic inspiration, the importance of the spiral geometry, the integration into existing processes and the wide range of possible applications of GKD's vortex separation unit from GKD...

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Dynamic sieve filtration of suspensions with high solids concentration

E. Ehrfeld*, K. Neumaier, BOKELA GmbH, Germany

The reliable separation of interfering coarse particles from dispersions or absolute filtrate clarity is of great importance in many processes. Dynamic filtration and screening with the BoCross filter enables efficient solutions for both classification and clear filtration tasks where state-of-the-art processes such as wedge wire screens, cartridge and backwash filters, vibrating screens, centrifuges, cyclones or membrane filtration reach their limits.

In particular, the sieving of suspensions with a high particle concentration is not possible or not recommendable with the above-mentioned devices, or at least the suspension must be diluted before sieving. Depending on the task at hand, the Bo-Cross filter can be used to implement various processes tailored to the product and objective. Accordingly, a base layer on the separation medium can be reliably prevented or deliberately adjusted. The article explains the possible operating modes with a focus on screen filtration for separating unwanted coarse particles from highly concentrated suspensions. The aim is to achieve a continuous filtrate throughput with a high concentration of fine particles that is still capable of flowing.

Options are explained using two application examples: It is shown how the BoCross filter is used to continuously sieve off interfering coarse particles from a highly concentrated, viscous dispersion with a defined separation cut in a tightly sealed apparatus. The proportion of coarse material retained in the retentate is very low in relation to the filtrate throughput. Another example shows the separation of interfering mineral particles. The materials used here are used for coating electrodes. Even one particle protruding from the coating can lead to production rejects and must therefore be reliably removed.

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14:15h - Coffee Break


K02 - Keynote Lecture 02

Day: 12 November 2024
Time: 14:45 - 16:00 h
Room 1

Session Chair:
Prof. Hermann Nirschl

How filtration and separation impact global sustainability

Dr. W. Chen*, Dow, USA

Sustainability is a global effort to make our world better for ourselves and can sustain for future generations. The scope is so large and with tremendous challenges, so it needs to be a global effort and requires the participation of all industries. In this presentation, we will specifically look at the role of filtration and separation technologies in this global effort and how filtration and separation industry can contribute.

Key sustainability efforts are in carbon reduction, renewable materials, circularity, water and more. For carbon capture and reduction, amine filtration, membrane separation, and sorbents adsorption play very important roles. In the production of renewable materials, key challenges are often in the solid/liquid separation. To achieve circularity, filtration and purification of recycled materials are also challenging. Global water shortage makes water a key sustainability focus, either raw water supply, wastewater treatment, or water reuse, filtration and separation again are playing critical roles and the need for better technologies is ever growing. Overall, in all sustainability efforts, filtration and separation are crucial for reaching the sustainability goals.

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F01 - Bio-based Polymers as Alternative for Fossil Based Polymers

Day: 12 November 2024
Time: 14:45 - 16:00 h
Room 2

Exploring biopolymers as alternatives for fossil-based electret fibers in electrostatic filtration media

Y. Kiyak*, Gessner, USA

Electrostatic filtration media play a crucial role in various applications, including air purification, but predominantly rely on fossil-based polymeric electret fibers. As concerns about climate change and environmental pollution escalate due to increased fossil fuel usage, there is a pressing need to transition to renewable and sustainable materials. This study aims to explore bio-based and degradable materials as potential alternatives to traditional fossil fuel-based insulation materials for electrostatic filtration media. The research involves a comprehensive examination of the electrical properties of these materials to identify suitable candidates for full replacement or further development.

Dielectrics, which are materials with permanent electric dipole moments, are essential for electrostatic filter media, as they store electrical energy. The dielectric constant, a key property for these materials, influences energy storage and dissipation. For electrostatic applications, low dielectric constant is preferable, along with high thermal stability, mechanical strength, and low dissipation factor.

Polymers, as common dielectric materials, can be polar or non-polar depending on their chemical structure. Non-polar polymers are desirable for electrostatic fibers due to their high resistivity and low dielectric constants. Additionally, factors such as surface energy, crystallinity, and orientation play significant roles in determining the electrical properties of polymers.

The research investigates various bio-based and degradable polymers such as polylactic acid (PLA) and polyhydroxybutyrate (PHB) alongside conventional polymers. While PLA exhibits acceptable electrical, thermal, and mechanical properties, PHB shows good electrical properties but requires improvement in mechanical and thermal aspects. Some hydrocarbon ad fluorocarbon polymers are also compared as a state of the art for their exceptional dielectric properties.

The study delves into the relationship between chemical structure and electrical properties, highlighting the importance of understanding polarizability, polarity, dielectric loss tangent, and dielectric constant. It also emphasizes the necessity of measuring dielectric properties under similar test conditions for meaningful comparison.

Moreover, the research explores the influence of processing conditions and additives on the microstructure of polymeric fibers to manipulate their electrical properties. Results indicate that ...

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Biobased polymer alternatives for melt blown filtering materials

G. Masionė, D. Čiužas, E. Krugly, T. Prasauskas, D. Martuzevičius*, Kaunas University of Technology; M. Tichonovas, Bious Labs Tech, Lithuania

The air filter sector suffers from the reliance on nonrenewable materials such as minerals and petroleum oil, thus a shift toward sustainable materials must be intensively researched. Synthetic biobased polymers provide comparable properties to the petroleum derived ones, thus may be explored as alternative materials with potentially lower impact to environment through the entire life cycle. At the same time, the current availability of suitable synthetic biobased polymers is rather narrow, while their properties are not tuned for filter production. This study aimed to produce filtering materials using four types of commercially available biobased polymers through the melt blowing technique, and to characterize their properties.

The following fully or partially biobased injection-grade polymers were tested: poly (butylene succinate) (NaturePlast SAS), polyamide (EMS-Chemie AG), polylactic acid (TotalEnergies Corbion Ltd.), polyhydroxyalkanoate (NaturePlast), and a polyhydroxyalkanoates/polylactic acid blend (NaturePlast). The granules of the polymers were fed via a single screw extruder to a 0.2 mm nozzle melt blowing die, where high-speed hot air converted the molten polymers into fine fibers, which were then collected on a rotating drum to form a micro-nanofibrous nonwovens. Filtration efficiency, pressure drop, and mechanical properties.

The tested polymers were able to form nonwoven materials that possessed suitable mechanical properties, except PHA, which produced brittle fibres that did not form a suitable nonwoven matrix. The morphology of fiber matrixes is presented in Figure 1, displaying a mixture of sub-micrometer and micrometer fibres. Melt blowing conditions were varied to achieve the set efficiency (ePM1>80%)...

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Layered electrospun nano/microfiborus filtering materials from biobased polymers

G. Masionė*, D. Čiužas, E. Krugly, T. Prasauskas, D. Martuzevičius, Kaunas University of Technology; M. Tichonovas, Bious Labs Tech, Lithuania

Efficient air filtering materials are crucial for environmental health and industrial safety. Nanostructured fibrous materials offer improved capture of airborne particles and optimize filtration efficiency due to their fine dimensions and large surface area-to-volume ratios. On the other hand, these materials often suffer from an increase in pressure drop across the filtering layer and low mechanical stability. Thus, composite morphologies are being researched to optimize the filtration performance. This study aimed to fabricate and characterize multilayer nano- and micro fibrous materials. Moreover, the study employed commercially available biobased polymers to address the issue of non-renewable resources.

Layered filtering materials were fabricated using a fiber printing process (3Df-01C, Bious Labs, Lithuania) from commercially available biobased polymers, including poly (butylene succinate) (NaturePlast SAS) and polyamide (EMS-Chemie AG). This apparatus integrates melt and solution electrospinning to create micro and nanofibrous layers, respectively. Filtration efficiency was evaluated by challenging the matrices with aerosolized NaCl and DEHS solutions using a filter material setup developed at KTU and measuring particle concentrations with an electric low-pressure impactor (ELPI+, Dekati Ltd.).

A range of nano/microfibrous filtering materials was obtained (Figure 1) through various layering schemes, allowing controlling filtration efficiency between 70 to 99%. The optimum layering patterns were selected based on the lowest filter quality factor.

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G03 - Adsorption II

Day: 12 November 2024
Time: 14:45 - 16:00 h
Room 3

Adsorptive filter media in cabin air filtration: Advancing filter design through modeling

S. Gulrez*, K.R. Patchigolla Venkata, M. Silin, K. Joshi, Hollingsworth & Vose, UK

Gas phase filtration has gained much attention due to increased pollution level, growing public awareness and issued guidelines by regulatory bodies on global air quality1. In the cabin air segment, OEMs and filter element manufacturers demand higher removal efficiency of VOCs and harmful toxic gases, in addition to high particulate filtration targets, dust holding capacity and lower pressure drop. To address these challenges, we will describe an innovative media, that combines high-quality adsorbent layer and next-generation particulate filter layers for improved performance. This data will be supported by computational modeling.

In this study, we illustrated the media developing workflow through a case study to meet element performance and VOC removal requirements. An alternative carbon composition was engineered based on the model. Its performance was further confirmed via in-house flat sheet media testing. Finally, the optimized solution was validated through complete filter element testing.

The semi-analytical model developed in this work has demonstrated the capability to predict the adsorption performance of flat sheet carbon media and pleated filter elements for multiple application environments involving different flow rates, various upstream concentration levels, and a wide range of carbon add-on in the media.

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Removal of formaldehyde by activated alumina loaded platinum

Y.-C. Chen, C.-D. Ye, T. Lin, C.-H. Tseng, A. Shiue, S.-C. Hu*, National Taipei University of Technololgy, Taiwan

Currently, most of the commercial air cleaners available use physical adsorption of formaldehyde with activated carbon. According to past studies however, activated carbon has a poor formaldehyde adsorption ability. To improve the removal of indoor formaldehyde pollutants more effectively, this study will utilize the principle of catalytic oxidation and adsorption by using alumina loaded Platinum to conduct column adsorption experiments, to understand its adsorption.

The Scanning Electron Microscopy (SEM) analysis shows that the surface characteristics of alumina loaded Platinum are agglomerated with minor debris. As the concentration of the hydrochloric acid solution increases, the surface becomes smoother. Moreover, the Energy-Dispersive X-ray Spectroscopy(EDS) found that sample A0 had Platinum aggregation and agglomeration and it contained the most Chlorine elements based on all samples tested. According to the High Resolution Surface Area and Porosimetry Analyser(BET) analysis results, the specific surface area decreased only slightly, and as the hydrochloric acid concentration increased, the lesser the specific surface area became. The Fourier Transform Infrared Spectroscopy(FTIR) and X-ray Diffractometer(XRD) analysis results are not significantly different from those of OA, and the XPS analysis results show that Al 2p had a negative shift. In addition to this, the ICP analysis results detected...

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Solid-gas filtration: a critical component of strategies for improved air quality and public health

I. Merino*, A. Doche, E. Andreu, Bioconservacion S.A., Spain

The WHO has recognized air pollution as an invisible health threat responsible for about 7 million premature deaths per year, of which 3,8 million are attributed to indoor air quality. Due to the associated link between air quality and health, the general concern about improving air quality has been significantly increased in the past years. Various air treatment technologies have gained interest, including physicochemical technologies (e.g.: filtration (HEPA), adsorption, UV-photocatalytic oxidation, ozone generator, plasma, ultraviolet disinfection and ionization) and biological technologies (e.g., plant purification methods and microalgae-based methods).

Although their performance is well defined and very efficient in specific areas, there are several limitations to consider. One of the most common problems from these technologies is that they do not cover the simultaneous removal of all pollutant types, including microorganisms, gaseous contaminants and particles. Most of these technologies do not remove any of the harmful gaseous indoor contaminants (VOCs, formaldehyde, NOx, SO2…) and sometimes, they emit more dangerous pollutants than those they can remove. For example, the release of toxic byproducts (such as ozone) by all kinds of UV or plasma purifiers should be carefully controlled and efficiently removed. Other technologies focus on the removal of microorganisms and do not focus on eliminating gas pollutants at all. To ensure a fully effective indoor air purification, the optimal solution appears to be the combination of different technologies. Some purifiers contain activated carbon foams as a mean of removal of volatile organic compounds generated indoor or the ozone generated from the purifiers. However, the adsorption capacity and gas type selectivity of these activated carbon foams is very limited, not reaching its purpose.

For the appropriate removal of most indoor gaseous pollutants, a blend of at least two different types of absorbent media is needed. A high surface area active carbon should be used for efficient physisorption of ozone and high molecular weight volatile organic compounds (VOCs), and a different type of adsorbent, including some chemically active ingredient, such as potassium permanganate, favoring the chemisorption of formaldehyde, ketones, aldehydes, alcohols NOx, SO2, among others, is required. Other types of adsorbents can also contribute to the removal of amines and ammonia, which when generated indoor can cause health effects associated with strong odors.

In this work, we critically review and address the limitations of the most commonly used air filtration technologies through the implementation of a novel, holistic combination of air purification systems, air conditioning systems, and physical and chemical gas adsorption systems. Laboratory test have been performed with adsorbent media with promising results in the adsorption of NOx, SO2, and formaldehyde. This integrated approach leverages the strengths of each technology, providing a comprehensive solution that ensures both comfort and healthy indoor air.

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G04 - Measurement Techniques

Day: 12 November 2024
Time: 14:45 - 16:00 h
Room 4

Development and experimental measurements of a high flow rate respirable cyclone sampler

D. Misiulia*, S. Antonyuk, University of Kaiserslautern-Landau (RPTU); C. Möhlmann, German Social Accident Insurance (DGUV), Germany

Personal cyclone samplers have been widely used to measure the respirable mass of particles in occupational and ambient environments. In respirable dust sampling, it is essential that the cyclone cut-off characteristics be known and constant, and that each cyclone be operated at a flow rate, which produces the desired cut-off. The personal sampling methods used today comprise air flows up to 10 l/min. This work aims to develop a 20 l/min sampling cyclone that meets the sampling efficiency curve, determined by respirable convention EN481.

Based on the previous numerical study, the cyclone of the GK design showed the lowest deviation compared to the respirable convention and therefore was used for further investigation. The GK cyclone with an internal diameter of 6.27 cm was manufactured in two versions, one from steel and another from plastic by 3D-printing.

The following experimental setup was developed. Solid glass spheres Ballotini 3000 with a 2.5 g/cm3 density were dispersed into an open aerosol box by the generator RBG 1000. The generated aerosol was drawn through the cyclone sampler, then through the filter located downstream to deposit non-collected in a cyclone sampler aerosol particles, and finally through the flow meter TSI4040 and flow control valve by the usage of a vacuum pump. Particle concentration of different sizes upstream and downstream of the cyclone was measured by the aerodynamic particle sizer APS 3321. The penetration curves were calculated based on the particle concentration upstream and downstream of the cyclone sampler.

Two cyclones were tested at a flow rate of 20 l/min and the measurements were performed at two different sampling flow rates, 1 l/min and 5 l/min to reveal its effect on the results of measurement.

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Breakthrough sensor for adsorption filters

M. Lauer*, D. Kochale, A. Türke, Institute of Air Handling and Refrigeration (ILK), Germany

Sorption material in gas cleaning units that serve occupational health and safety must be changed at an appropriate early stage. The instructions from the professional associations stipulate that driver's cabs must have an appropriately equipped ventilation system when used in contaminated areas. However, the standards for the sorption filter specified in the document only contain the type of filter test and no recommendations for the duration of use. The research project at the ILK Dresden aims to develop a sensor system for the safe monitoring of the operating status of a sorption device for the separation of gaseous substances from air. The sensor we develop will convert the loading status of the sorption agent into an electrical signal so that a warning message can be issued to the user or the system control when a threshold value is reached. The measurement is carried out via the electrical capacitance at a frequency and a specific measuring voltage. Capacitance/voltage converters are used, which enable a simple evaluation to be carried out. Such ICs (interdigital circuits) cost between 10 and 30 €. The evaluation unit includes the sensor unit, so they are reusable. The price also allows several sensor elements to be queried in the filter element, which means that the resolution of the adsorption front can be mapped more precisely. It is essential to record the moisture, as the water retention dominates the loading of the sorbent. This observation is confirmed by measurements carried out at the ILK Dresden on pollutant filters actually used. The filter elements used were exposed to 70% humidity and the test gas cyclohexane at the nominal volume flow. One filter element showed an immediate breakthrough with the simultaneous release of moisture into the clean gas. The sorbent is evidently saturated with water. Therefore, sensor elements for temperature and humidity are placed up and downstream of the filter. We prefer printed electronics for these sensors. Results will be discussed...

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Welding dust seperation – new test method to meet actual reglementation of heavy metals at workshop places

R. Heidenreich*, S. Herrmann, D. Keßlau; Institute of Air Handling and Refrigeration (ILK), Germany

The European Commission is currently discussing the importance of introducing new limit values for the exposure of employees and a limit value for welding fumes. What is being examined here is whether a general limit value for welding fumes in the Directive on Carcinogenic, Mutagenic, and Reproductively Toxic Substances (CMRD) 2004/37/EC is included in Annex I of the CMRD list. However, there are already difficulties in complying with existing limit values. The WELDOX project by DGUV still includes accurate information about welding fume concentration levels. That means concentrations in the workplace are often in the limit range of the AGW (1.25 mg/m³), but the AGW for manganese (0.02 mg/m³) is often significantly exceeded. Our measurements also confirmed this in metal companies in Saxony. What makes matters worse is that there is no test procedure to determine the separation effect of industrial vacuum cleaners for manganese. However, VDI 2262 requires this to allow clean air to return. Specifically, the clean air concentration must be a factor of 0.2 (4 mg Mn/m³) below the AGW. A verification procedure for testing welding fume separators is currently being developed at ILK Dresden.

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16:00h - Coffee Break


F02 - Adsorption of Substances on Filter Media

Day: 12 November 2024
Time: 16:45 - 18:00 h
Room 3

Self-driven sustainable oil-water-separation by bio-inspired textiles

L. Beek*, T. Gries, RWTH Aachen University; K. Klopp, Heimbach GmbH; M. Mail, W. Barthlott, University of Bonn, Germany

Despite the steady expansion of renewable energies, global oil production, oil consumption and the risk of oil pollution have increased steadily over the last two decades. In 2022, global oil production amounted to 4.4 billion tons. Accidents often occur during the extraction, transportation and use of oil, resulting in serious and sometimes irreversible environmental pollution and harm to humans.

There are various methods for removing this oil pollution from water surfaces. However, all methods have various shortcomings that make them difficult to use and, in particular, limit the removal of oil from inland waters.

For many technical applications, unexpected solutions come from the field of biology. Millions of years of evolution led to optimized surfaces of living organisms for their interaction with the environment. Solutions - often rather unfamiliar to materials scientists and difficult to accept. The examination of around 20,000 different species showed that there is an almost infinite variety of structures and functionalities. Some species in particular stand out for their excellent oil adsorption properties. It was shown that ...

The observations were the inspiration to transfer the effect to technical textiles for separating oil and water. The result is a superhydrophobic knitted spacer fabric that can be produced industrially and is therefore easily scalable. The bio-inspired textile can be integrated into a device for oil-water separation. This entire device is called a Bionic Oil Adsorber (BOA). Starting from the contamination in the form of an oil film on the water surface, the separation and collection process works according to the following steps...

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Bamboo based activated carbon-characters and applications

M. Shen*, Huaqing Activated Carbon; H. Mingyu, Ningbo Tianyi Activated Carbon Co. Ltd, China

The paper will review commercially available bamboo based activated carbon and benefits of using bamboo as one of eco-friendly materials for manufacturing activated carbon. Key factors that affect activated carbon characters and performance such as manufacturing process (chemical and steam activation) and raw material (pore size and surface functional groups) will be discussed. Normal activated carbon specifications such as iodine value, total pore volume, pore size distribution, density, etc. are used to evaluate and compare the bamboo based with other materials (coal or coconut) based activated carbon. Paper will focus on advantage of bamboo based activated carbon characters such as (1) biomass sustainable material, (2) utilization of agriculture waste, (3) low carbon foot print, (4) large pore volume, and (5) well-developed micropore. Finally, potential and examples of bamboo based activated carbon applications in VOCs control, catalyst

substrate, odor control, etc. will be discussed.

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Simplified ultrasound-mediated creation of CuFe-layered double hydroxides/g-C3N4 nanocomposite for enhanced sono-sorption of alizarin red S.

R. Eizi, T. Rohani Bastami, A. Ayati, H. Babaei, Quchan University of Technology; V. Mahmoudi, University of Gonabad, Iran

Background: Layered double hydroxides (LDHs) have garnered considerable attention owing to their remarkable performance and diverse applications. This study focuses on the synthesis of innovative CuFe-LDH/g-C3N4 (CFL/CN) nanocomposites using an ultrasound-assisted method.

Methods: The generation of nano-sorbents, termed CFL/CN, was accomplished through ultrasonic wave exposure in a sonicator tank. The hydrothermal method was employed to investigate the influence of ultrasonic waves on the morphology of CFL/CN nano-sorbents. Characterization of the nano-sorbents, synthesized via hydrothermal and sonication methods, involved the application of various techniques, including XRD, FTIR, XPS, SEM, TEM, and BET. Furthermore, the efficacy of the prepared nanomaterials in the removal of alizarin red S (ARS), employed as a model pollutant, was assessed through both adsorption and sono-sorption methods.

Conclusion: This study presents a straightforward method for synthesizing the CuFe-LDH/g-C3N4 nanostructure using hydrothermal and sonochemical approaches. The adsorptive removal of alizarin red S (ARS) from aqueous media was investigated employing the synthesized sorbents (CuFe-LDH, Hydro-CFL/CN, and Sono-CFL/CN) under various experimental conditions, with and without ultrasonic irradiation (US and MS methods). In comparison to alternative sorbent materials, Sono-CFL/CN emerges as a promising nano-sorbent with substantial potential for the efficient adsorptive removal of ARS from aqueous solutions. The increased efficiency observed for ...

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G05 - Surface Filtration

Day: 12 November 2024
Time: 16:45 - 18:00 h
Room 4

Comparison of the measurement and calculation of pressure drop of surface filters at low system pressures

V. Löschner*, J. Meyer, A. Dittler, Karlsruhe Institute of Technology (KIT), Germany

Some applications in gas particle separation processes run at low absolute pressures, for example the cleaning of the vapour stream during vacuum drying. Surface filter media are used in this application to allow the recovery of the mostly high-quality products. So far, not much is known about the operating behaviour of filters at low system pressures. Previous studies have been limited to depth filters. The dimensioning of the filters is thus based on data for filtration at ambient pressure. This often leads to incorrectly dimensioned filter sizes. To prevent this, a fundamental understanding of the filtration processes with surface filters at low system pressures is required.

An essential parameter in gas filtration is the pressure drop of unladen surface filter media. In this work, the differential pressure of unladen surface filter media was measured for two different types of filter media with a widely differing structure at two filter face velocities as a function of the absolute pressure. The system pressure was varied in a range of 1 - 1000 mbar. Furthermore, a semi-empirical model was developed that allows the differential pressure of surface filter media to be calculated as a function of the system pressure for the entire Kn-number range...

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Doubling the service life of air filters by use of nanofibers

L. Beek*, T. Schneiders, T. Gries, RWTH Aachen University; J. Nosper, WKI Absaugtechnik GmbH, Germany

Air filter systems are used in a variety of industries, e.g. in the food sector, where particularly high product quality and purity (according to ISO 16890 effectiveness classification) is required. Dust and foreign particles, as well as smaller foreign bodies such as microorganisms, are removed by use of filters. The separation performance of bag filters for industrial dedusting is not based on the retention of the actual filter medium alone, but also on the filtering effect of the dust cake that forms on the filter surface. As the load increases, so does the pressure loss on the filter, so that it has to be cleaned. However, a sufficient cleaning is usually not achieved on conventional bag filters. This results in an increased residual pressure loss compared to the new filter medium. It increases steadily during operation and thus drives up energy consumption. If the residual pressure loss is too high, the filter medium must be replaced.

Filters based on surface filtration can eliminate these deficits. For this reason, it was the aim to develop a bag filter for dedusting plants based on surface filtration using an adapted filter medium made of nanofiber nonwovens.

Initially, the nanofiber nonwoven was developed on a laboratory scale by nozzle type DC solution electrospinning. For this purpose, a detailed parameter study was conducted before upscaling of the process was investigated. In this study, spinning parameters for polyamide 6 (PA6) and polyvinylidene fluoride (PVDF) were adapted in a factorial design study for a single nozzle setup. With PVDF, average fiber diameters between 84 and 106 nm were achieved. For PA6, the fiber diameter averages range from 157 to 250 nm. In the final lab-scale, it was successfully demonstrated that scale-up of spinning PA6 using up to 24 nozzles allowing a production rate of 9.42 g/h is possible.

On this basis, nanofiber nonwovens were transferred to an industrial production plant. It was possible to continuously coat carrier materials with a width of 1 m on this plant. To improve the adhesion of the nanofibers to the carrier material and to protect them from abrasion in the subsequent processing steps, an acrylic dispersion was applied ...

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The potential of computational fluid dynamics (CFD) for efficient pulse-jet cleaning of fabric filters: Part 2 - characterization of a practical solution

G.V. Messa, D. Scaccabarozzi, C. Martina, Politecnico di Milano; C. Maggi*, L. Montanelli, CleanAir Europe S.r.l., Italy

The pulse jet method stands as a firmly established means for cleansing fabric filters. It leverages the mechanical force of a compressed air jet, generating a pressure wave that traverses the bag filter, dislodging
dust accumulation from its surface. Preceding this, an initial step entails employing Computational Fluid Dynamics (CFD) techniques to simulate airflow. With the continuous advancements in computing power and
simulation software capabilities, CFD finds application across diverse engineering domains involving fluid dynamics. Notably, CFD offers extensive data distribution, relatively economical implementation, and the
virtual capacity to simulate any flow process irrespective of complexity or scale. However, a primary challenge highlighted in prior research lies in the considerable computational demands, encompassing both processing time and memory requirements. Particularly in scenarios involving turbulent flows, the fundamental fluid flow equations derived from mass, momentum, and energy conservation principles necessitate mathematical manipulation and subsequent numerical approximation for computational handling. This process yields coefficients, parameters, and closure equations, often empirical and poorly characterized, compelling users to make subjective decisions and introducing uncertainty into simulation outcomes. Consequently, the focal challenge for CFD practitioners lies not merely in solving equations, but rather in configuring settings such as sub-models and parameters—to ensure dependable numerical forecasts. To address this, a specific parameter set and sensitivity analysis have been conducted and found to be the most accurate possible tradeoff among time and cost.

This study highlights the potential of CFD in fabric filter pulse jet cleaning. While previous research has explored CFD's role in simulating this process, it has mainly been limited to pioneering or recent investigations
of the entire cleaning operation. In contrast, this study aims to evaluate CFD's practical effectiveness as an engineering tool, focusing on accuracy, robustness, and computational efficiency...

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L02 - Particle and Solid Structure Characterization

Day: 12 November 2024
Time: 16:45 - 18:00 h
Room 1

Session Chair:
Prof. Dietmar Lerche

Direct fluorescence detection of aquatic micro and nanoplastics using a targeting fluorochrome

R.I. Peinador*, Institut de la Filtration et des Techniques Séparatives (IFTS), France

This paper presents an innovative methodology for the detection of primary and secondary microplastics and nanoplastics (MNPs) in diverse aquatic environments using the fluorescent dye Nile Red-n-heptane (NR-H). The escalating pollution from plastic waste and its subsequent fragmentation into MNPs has become a critical environmental issue, infiltrating ecosystems and posing significant ecological and health risks. Traditional methods for detecting MNPs often involve lengthy and costly sample preparation and extraction processes. Our approach seeks to address these limitations by enabling rapid, in-situ detection of MNPs directly in water samples.

Our method leverages the hydrophobic properties of NR-H, which selectively binds to plastic particles, allowing for their detection under fluorescent microscopy. This study demonstrates the effectiveness of the NR-H staining technique across various types of water, including wastewater, borehole water, seawater, and synthetic seawater. The methodology was rigorously evaluated using scanning electron microscopy (SEM), dynamic light scattering (DLS), and optical microscopy to validate the presence and characteristics of MNPs.

Key findings include the successful detection of...

Our study further explored the quantification capabilities of the NR-H technique, addressing potential limitations in sensitivity and specificity. The use of a submersible fluorescence probe was incorporated into the protocol, facilitating real-time, direct measurements in situ. This development is particularly advantageous for environmental monitoring, offering a practical tool for mapping plastic pollution in various aquatic settings.

The research also highlighted the adaptability and robustness of the NR-H method in different environmental conditions. Tests conducted in saline littoral waters and other challenging environments confirmed the method's reliability and precision. These validations underscore the method's potential for broader application in environmental science and pollution management.

One of the notable advantages of this method is its contribution to ...

Further research is proposed to refine the quantification aspects of the NR-H method and to expand its applicability to a wider range of polymer types and environmental conditions. The development of standardized protocols and the potential integration of advanced spectroscopic techniques, such as fluorescence lifetime imaging (FLIM) and hyperspectral imaging, are recommended to enhance the specificity and accuracy of MNP detection.

In conclusion, this paper presents a significant advancement in the field of environmental microplastic detection. The NR-H based method offers a practical, efficient, and reliable tool for the rapid identification and quantification of MNPs in diverse aquatic environments. By addressing the critical need for effective monitoring and management of plastic pollution, this research contributes valuable insights and methodologies that can support global efforts to protect and preserve aquatic ecosystems...

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Investigation of the permeability of ceramic foam filters by x-ray tomography

S. Daus*, U.A. Peuker, Technical University Bergakademie Freiberg, Germany

Ceramic Foam Filters (CFF) are widely used in metal melt filtration to obtain high-quality casting products. These filters are characterized by their highly porous, open-cell structures and good mechanical, chemical and thermal stability. The permeability of the filters is a critical parameter because it offers insight into flow characteristics through the filter, which in turn contributes to optimizing filter design, selecting suitable pore sizes, and maintaining consistent metal flow rates during casting. Several correlations for calculating the permeability can be found in the literature. However, these differ greatly in both form and resulting permeability values. In most cases, one or more fitting parameters are used to fit the equation to the data. This results in a lack of transferability to new filters. Comparisons between different equations show large deviations of up to 600% [1]. The reason for this is that the structural properties of the filters vary considerably between different suppliers, even for filters with the same nominal pore size [2]. In addition, the morphological and hydraulic parameters are not uniformly defined or measured across studies, highlighting the need for a systematic approach towards characterizing CFFs.

The present work shows that it is possible to predict the permeability of ceramic foam filters without needing correlations specifically designed for CFFs. Instead, the key to accurately estimating permeability is the precise determination of the structural characteristics of the filters, such as pore size, shape, porosity, and tortuosity. To achieve this, the structural parameters of 10 and 30 ppi filters were investigated using µ-CT measurements. As pore size appears to be the most critical parameter, different equivalent pore size diameters are compared. Experimental permeability values obtained from pressure drop measurements at varying flow rates are used to validate the calculated permeabilities...

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Beyond the lab: Pioneering simulation-based research with artificial filter cake structures through 3D x-ray tomography validation

E. Löwer*, P. Gräfensteiner, O. Furat, V. Schmidt, U. A. Peuker, Technical University Bergakademie Freiberg, Germany

Particle systems and bulk structures, such as a filter cake, are composed of a multitude of individual particles that exhibit diverse properties. Consequently, they are described by probability distributions. However, as often only equivalent parameters are measured, only a limited number of measurement methods are able to resolve several properties simultaneously in a particle-discrete manner, i.e., to generate an information vector of its properties for each particle. In this context, three-dimensional imaging techniques offer a distinct advantage, enabling the determination of multivariate distributions. Modern optical measurement techniques, such as X-ray microscopy, are capable of generating large image data sets, which can greatly enhance the information yield for process engineering studies [1-3].

In process models, this information is often reduced to a discrete absolute value, which is only able to quantify the particle system or the resulting property function to a limited extent. A review of the literature reveals that the resulting integral parameters are not sufficient to describe or model process engineering effects in sufficient detail [4-6].

The use of distributions is also required in cake filtration, particularly given that the structure of the cake is described by parameters that are also distributed. These include pore diameter, tortuosity, number of contact points, volume of isolated liquid clusters, capillary pressure, contact angle and local porosity.

The objective is to correlate distributed multidimensional particle properties, such as particle size and shape distribution, with distributed parameters of the 3D morphology of the pore space composed of these particles. This is to be achieved by combining experimental process engineering with digital computational methods.

However, the variety of available tomographic image data is often insufficient to permit the reliable determination of transfer functions. One approach resolving this issue is to expand the database through the use of model-based simulation of virtual, yet realistic, filter cake structures.

The initial step is to utilize a stochastic modelling approach to generate the virtual filter cakes, whereby the model parameters are calibrated and validated utilizing tomographic image data. The model simulates two distinct particle systems, namely glass beads and crushed quartz particles, by generating artificial particles of irregular shape utilizing mixed Gaussian random fields on a sphere. These are then spatially arranged to form a three-dimensional artificial filter cake, which is validated with respect to geometric descriptors not used for model fitting, such as constrictivity, porosity, tortuosity and specific surface area.

A broad spectrum of virtual 3D filter cake structures will be ...

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L03 - Numerical Simulation of Solid-Liquid-Separation Processes

Day: 12 November 2024
Time: 16:45 - 18:00 h
Room 2

Session Chair:
Dr. Ralf Kirsch

Multiscale simulation of polymer melt flow through wire mesh filters

P. Toktaliev*, R. Kirsch, M. Krier, D. Niedziela, D. Neusius, Fraunhofer Institute for Industrial Mathematics (ITWM), Germany

Stainless steel wire meshes are known for their mechanical strength, corrosion resilience and thermal stability. These properties make them ideal for cleaning highly viscous fluids such as polymer melts. The latter are non-Newtonian and therefore, when simulating the flow through a wire mesh filter, the shear-thinning behavior must be considered properly to obtain accurate results for the pressure drop and filter efficiency.

As an example, the present talk studies the flow of polypropylene (PP) melt through wire meshes under the conditions during the production of meltblown filter media. A two-step multiscale approach is used to describe the non-Newtonian flow phenomenon in polymer melt flows both at the micro- and macroscopic scales. To reconstruct the microgeometry of the filter element, a parametric solid representation of the individual wires and their contact regions [1] is used.

On the macroscopic scale of the filter element, a direct numerical simulation of the filter weave, i.e. resolving all the pore spaces in the computational grid, would be very costly in terms of computational effort. Instead, a representative elementary volume (REV) of the weave is chosen and represented in a computational grid with sufficiently fine resolution. Based on the non-Newtonian viscosity law w.r.t. temperature and shear rate and experimental data, CFD simulations [2] are carried out for different temperatures and flow rates.

The results are used to obtain the effective flow resistance of the wire mesh which allows for an upscaling of the simulation to the macroscale. In addition, the velocity field of a Newtonian fluid which causes the same pressure drop for the given flow rate is compared with the local velocities of the melt. The difference is relevant for micro-scale simulations of the transport and deposition of solid particles.

The talk also presents several examples for the multiscale simulation of PP melt flow in wire mesh filters and discusses the results...

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Numerical modeling of solid-liquid separation and cake formation processes: Increasing the computational efficiency

V. Puderbach*, A. Ataei, K. Schmidt, IT for Engineering (it4e) GmbH, Germany

Numerical simulation of filtration processes is used to investigate and improve filtration characteristics especially on the microscale. Coupling of computational fluid dynamics (CFD) with the discrete element method (DEM) is a simulation approach which allows to model all essential microscale effects which occur in solid-liquid filtration processes. The software DNSlab® provides different numerical methods that can be used for such simulations, namely the Lattice Boltzmann Method (LBM) and Finite Differences (FD) methods for the fluid dynamics, coupled with the DEM for the particle modeling.

In previous research [Puderbach, 2021] the LBM was used to describe the filtration behavior of solid spheres in solid-liquid separation processes using 2-way coupling of fluid and particle interactions. The investigations show good agreement of the experimental and numerical results. The 2-way coupling with the LBM allows a very accurate simulation of the particle motion in the fluid, but due to the 2-way coupling it is a very computationally intensive and time-consuming method.

The new 1½-way coupling approach is a further development by omitting too detailed computations which have only a neglectable effect on the filtration characteristic [Schmidt, 2021]. Unlike as for the 2-way coupling, the CFD for the 1½-way coupling doesn’t have to be done by the LBM, the resource-saving FD method can also be used. The approach still allows to simulate the particle deposition and detachment, especially by backwashing the filter cake, but requires significantly less computing resources.

The following figure shows the comparison of simulation and measurement for the separation of glass particles from water at a metal wire mesh [Puderbach2021

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CFD as a tool for optimization of solid bowl centrifuges: Achievements and future challenges

M. Gleiß*, H. Baust, Karlsruhe Institute of Technology (KIT), Germany

Computational Fluid Dynamics (CFD) is now well established in many areas of the process industry and is a powerful tool for process optimization. CFD simulation in the field of solid-liquid separation poses several challenges, such as the description of particle and apparatus size scales, complex computational domains, and the integration of the material behavior of the disperse and continuous phases.

This talk presents the development of a framework for the CFD simulation of the long-term process behavior for different types of solid bowl centrifuges. This enables an in-depth understanding of the physical processes in the centrifuges and the use of this data for the development of real-time process models. An important prerequisite for the applicability of the presented framework is the integration of the material behavior of the suspension, which is measured experimentally on laboratory equipment.

However, this leads to the fact that CFD simulations of multiphase flows for solid bowl centrifuges are always based on assumptions that lead to deviations between experiment and simulation. Therefore, developed models require extensive verification by comparing simulation results with experimental data. Furthermore, the influence of the assumptions made, and the limitations of the developed framework will be discussed in this presentation.

Finally, the challenges for a broad applicability of the developed CFD models in solid-liquid separation are discussed and future trends for CFD simulation are shown.

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F03 - Trend Towards Sustainable Filtration Technologies

Day: 13 November 2024
Time: 09:00 - 10:15 h
Room 2

Carbon footprint reduction strategies for the filtration industry

M. Van Hooreweder*, HALLBAR, Belgium

The filtration industry plays a critical role in maintaining environmental quality. In this sense one can say the filtration industry has a good carbon handprint[1]. However, the sector itself contributes to the global carbon footprint through energy-intensive manufacturing processes, material usage, complex supply chain and downstream emissions.

This paper explores various carbon footprint reduction strategies tailored for the filtration industry. In a first step this paper will look at scope 1 and scope 2 emission reduction strategies such as the adoption of energy-efficient production technologies, the production of sustainable and recyclable materials, the implementation of alternative business models and supply chain optimizations in function of CO2 emissions.

In a second step, this paper will investigate the impact on scope 3 emissions. This will include product design based on downstream energy efficiency, product life extension strategies and waste minimisation strategies.

Three case studies will highlight the successful implementation of these strategies, demonstrating their feasibility and benefits. Carbon+Alt+Delete is the software platform that manages the carbon accounting process. Emission factors are based on the Emission Factor Library and reporting is in line with the Greenhouse Gas Protocol.

[1]Carbon handprint is the opposite of carbon footprint. It recognises the actions you take to have a positive impact on CO2 emissions.

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Fast and reliable product carbon footprint evaluation by implementing a data driven and automated methodology

A. Kilian*, J. Ziegler, L. Spelter, MANN+HUMMEL GmbH, Germany

Moving towards carbon‑neutrality is one of the most challenging and important goals for the coming years. Regulatory frameworks are in place to guide the industry along the path and life cycle assessment (LCA) has been established as one of the most common methodologies for quantifying sustainability. To do this, principles are provided in standards as EN ISO 14040/44 and specific rulebooks have been developed to describe the assessment in more detail (Catena-X, 2023).

An LCA is a systematic analysis of environmental impacts over the course of the entire life cycle of a product. It typically includes the different stages ranging from raw material extraction and processing over manufacturing, logistics, and distribution until the use phase and end‑of‑life (cradle‑to‑grave). Focusing on the contribution to global warming potential (GWP) the sum of greenhouse gas emissions is estimated as CO2eq in a product carbon footprint (PCF). Correlated to these stages, the carbon emissions are reported in different scopes: direct and indirect emissions within the own production (scope 1 and 2) as well as indirect, upstream and downstream emissions, outside the direct control of the company (scope 3).

Conducting PCFs for a broad product portfolio is not feasible using a typical commercial software which demands for high manual efforts. Describing the several stages is time consuming as it involves extracting and evaluating all the required input data from numerous internal and external data sources. Especially for scope 3, which is usually the dominating contributor to the entire PCF, the data acquisition can be very challenging, depending on the supplier base, variety of purchased parts or materials as well as data quality and availability.

To overcome these challenges, a standardized and automated process following a data‑driven approach is crucial to rapidly generating PCFs, providing a robust database for further strategic planning. To achieve a holistic description of the product‑related CO2eq on a material as well as on a part level, information from different sources must be linked to ensure data quality and reliable results. Therefore, it is essential to...

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Application of renewable materials for more sustainable filter elements

L. Spelter*, S. Grebhardt, MANN+HUMMEL GmbH; U. Herkommer, ZELU CHEMIE GmbH; Germany

Becoming carbon neutral is the ultimate goal for the years to come. By establishing a circular economy and reducing the usage of crude-oil based products, important steps can be made right away. Filter elements are often used only once and disposed after they reached a certain level of pressure drop or change interval. The recycling of such highly contaminated waste is challenging and the reverse logistics difficult, especially in the independent aftermarket. Therefore, the choice of raw materials is especially important to reduce the impact on the environment because the materials are mainly incinerated or land-filled at end of life.

The product carbon footprint can be reduced significantly by using alternative materials from recycled or renewable feedstocks. However, these materials need to fulfil all customer requirements and to pass automotive test standards. Recycled plastics are in the focus of the automotive industry to fulfil upcoming legal requirements, especially the plastic recycling rate of at least 25 % in the “Directive on end-of-life vehicles” of the European Commission. The presentation shows the industrial application of recyclate plastics, renewable feedstock for sealings and filter media resins to air, fuel, oil and cabin air filters.

Since many years gaskets made of polyurethane foam function as sealing between filter elements and their housings. These are usually petrol based 2-component systems composed of MDI (isocyanate component) and polyether polyols (polyol component). But especially for polyols, there are various possibilities to replace basic material crude oil. Polyols based on vegetable oils such as soy bean oil, sunflower oil or corn oil are available. Castor oil is a very capable type of vegetable oil to produce polyurethanes. It is possible to adjust the functionality of castor oil-based polyols by dehydration. It enables the proportionate use of renewable raw materials for the composition of lowly cross linked, flexible products such as sealings. Preserving the required mechanical properties like tensile strength, elongation, hardness and resilience and the resistance against thermal stress, chemicals and ageing challenges the creation of the material.

In addition to the design of the filter element, the filter media itself plays a crucial role in the element's performance. For air and liquid filtration, the media typically consist of a combination of a cellulose-based filtration layer and a suitable resin system. The resin significantly contributes to the media's overall performance providing stability, rigidity, and chemical resistance. Depending on the needs, a phenolic, epoxy or acrylic resin can be used to stabilize the cellulose structure and to add e.g., flame retardant properties; using Bio-based feedstocks or ISCC+ certified materials will lower the carbon footprint significantly.

The presentation shows how these alternative materials can be applied in automotive filtration. The impact on the carbon footprint as well as the reduced usage of crude oil as a resource is assessed. Furthermore, details are provided regarding functional performance and product robustness in comparison to traditional designs and materials.

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G06 - Face Masks

Day: 13 November 2024
Time: 09:00 - 10:15 h
Room 3

Next generation FFP 2 Part I: Optimization of melt-blown and hydrocharging processes

W. Arne*, S. Antonov, D. Hietel, Fraunhofer Institute for Industrial Mathematics (ITWM); A. Rösner, Reifenhäuser Reicofil GmbH, Germany

The biggest challenge when developing filtering face pieces (FFP) is to guarantee the required level of protection while keeping breathing resistance as low as possible. For instance, the FFP2 classification according to the DIN EN 149 standard requires that at an air flow rate of 95 l/min, particle penetration must not exceed 6% and breathing resistance must not exceed 2.4 mbar [1].

The aim of the research project SULA (“Sicherer und leichter atmen”, engl.: ‘safer and easier breathing’) is to significantly reduce both penetration and breathing resistance by improving the manufacture and processing of the nonwoven fabric. Expertise from industry (Reifenhäuser Reicofil, IMSTec) and application-oriented research (Fraunhofer ITWM) is being pooled to investigate the interaction of the individual processes and their effects on the product.

For a meltblown nonwoven to meet the specifications, the fibers are electrostatically charged. In this project, the focus is on the hydrocharging technology, which is applied already during fiber production and thus promises an even distribution of the electric charge in the nonwoven.

In Part 1 of the contribution, we aim to analyze the impact of various process parameters on the charging characteristics of nonwovens, particularly focusing on the differences between electrostatic charging and hydrocharging, as this is the main driver to reduce the pressure drop resulting in lower breathing resistance for the face mask.

To increase the productivity of the filter layer the Multi-Row process is in favor to the well-established Single-Row process. Nonwovens produced by these methods exhibit distinct permeabilities and charges, affecting the quality of FFP2 masks.

Our goal is to enhance our understanding of the positive effect of hydrocharging in comparison with electrostatic charging through simulation and to adapt the superior performance of the hydrocharged single row process to the multi row process with increased productivity.

The entire meltblown process, including hydrocharging, is complex. Therefore, we are starting with modeling and validating individual aspects of the process. Initially, the water nozzle was modeled in a static airflow, simulated, and its performance validated against the nozzle manufacturer's measurements. The simulation results closely matched the actual measurements, both in terms of droplet diameter distributions and velocities. Subsequently, we modeled the high-turbulence airflow without considering hydrocharging effects and validated this model using measurements of Reifenhäuser Reicofil. Later, we incorporated the interaction between water droplets and the airflow into the model and conducted further validations. We measured water quantities at various positions of the water nozzles behind the air jet and compared these with our simulation results.

In the next steps we want to include all the effects of Meltblown process to get insight into hydrocharging process. With this knowledge we want to optimize ...

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Next generation FFP 2 part II: Material characterization, design and assessment of performance

R. Kirsch*, C. Mercier, K. Schladitz, M. Godehardt, Fraunhofer Institute for Industrial Mathematics (ITWM); E. Dahrmann, M. Tagliani, IMSTec GmbH, Germany

The biggest challenge when developing filtering face pieces (FFP) is to guarantee the required level of protection while keeping breathing resistance as low as possible. For instance, the FFP2 classification according to the DIN EN 149 standard requires that at an air flow rate of 95 l/min, particle penetration must not exceed 6% and breathing resistance must not exceed 2.4 mbar [1].

The aim of the research project SULA (“Sicherer und leichter atmen”, engl.: ‘safer and easier breathing’) is to significantly reduce both penetration and breathing resistance by improving the manufacture and processing of the nonwoven fabric. Expertise from industry (Reifenhäuser Reicofil, IMSTec) and application-oriented research (Fraunhofer ITWM) is being pooled to investigate the interaction of the individual processes and their effects on the product.

For a meltblown nonwoven to meet the specifications, the fibers are electrostatically charged. In this project, the focus is on the hydrocharging technology, which is applied already during fiber production and thus promises an even distribution of the electric charge in the nonwoven. The corresponding experimental investigations and the associated modeling and simulations are presented in Part 1 of the contribution [2].

This second part is dedicated to the characterization of the electret media produced and the model-based prediction of their protective effect and breathing resistance. The characterization includes basic properties such as thickness and surface weight. In addition, a workflow is being developed for the automatic detection of the nonwoven’s fiber diameter distribution, based on suitable sets of SEM images. In terms of performance, air permeability measurements as well as standard tests for the filter efficiency are performed for both flat sheet samples and mask prototypes. These experimental investigations are carried out for different aerosols (paraffin oil, sodium chloride) and volumetric air flow rates. The influence of the charging is studied by comparing the filtration efficiency for discharged samples of the filter materials with the charged counterparts. To quantify the effectiveness of the charging process, electrostatic fieldmeter measurements are performed on both sides of the flat sheet samples.

These data form the basis for the identification and calibration of models for the prediction of air flow resistance and fractional efficiency of the materials. The modeling allows for

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Quality concept for biobased medical face masks

H. Salmela*, I. Mattila, P. Heikkilä, T. Salmi, S. Salo, VTT Technical Research Centre of Finland Ltd., Finland

Biobased, biodegradable, and environmentally friendly materials have shown potential to substitute fossil fuel-based polymers in production of professional grade face masks. Although there is a good chance to alleviate the stress on the environment, the biobased medical face masks need to fulfill the same approval procedures as the current synthetic products. At the same time, the manufacturer needs to be aware of quality characteristics that may relate to the biobased origin.

The aim of the study is to establish a concept for a “chain of quality” for biobased facemask manufacturing that covers the steps from in-house checks to product approval and the use and dispose of the product.

The proposed quality control concept includes checks for raw material, nonwoven, prototype, product, shelf life, use, and disposal/recycling (Table 1). The quality checks are grouped in three categories: primary and secondary checks and product approval tests. Primary checks are conducted mainly in-house by the manufacturer utilizing quick standard or alternative tests. More detailed secondary checks are conducted mainly by a 3rd party with applicable resources such as microbiology laboratory. Product approval tests are conducted by an accredited test laboratory utilizing appropriate standards like EN 14683, ASTM F2100 or YY 0469-2011 depending on the target market.

The focus of the concept is on key technical parameters that affect the manufacturability and performance of the product. Criterion for manufacturability includes processability, mechanical strength, chemical properties, and market availability. Concerning product performance, the focus is on quick, reliable, and comparable evaluation of the main parameters for protection, that is, filtration efficiency and breathability, starting from early material and prototype development phases. The key hardware is a filtration efficiency measurement system for flat sheet materials that has been successfully adopted for rapid alternative measurements of face masks and mask materials. With this approach the R&D cycle of a mask can be speeded up and a deeper understanding of features affecting filtration performance studied in a lean manner.

Various bio-based materials are available for use in medical face mask production. After careful evaluation of different options, the quality concept is demonstrated with nonwoven materials and mask prototypes made of polylactic acid (PLA) polymer.

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L04 - Discontinuous Pressure and Press Filtration

Day: 13 November 2024
Time: 09:00 - 10:15 h
Room 1

Session Chair:
Prof. Ioannis Nicolaou

Optimal control of parallel pressure filtration systems

H. Aalto*, Take Control Oy, Finland

Pressure filtration, or cake filtration, is commonly used in chemical and biochemical industries as well as in the mining industry. Automatic control of multiple parallel filters simultaneously in order to increase total throughput is known to be challenging. Typically, a process unit has some processing steps upstream the parallel pressure filtration system (PPFS) including some buffer tank volume, which can be utilized for optimized throughput control.

It is a common practice to try to keep a constant volumetric flow rate through the individual filters during their running cycle for all filters in a PPFS, [1], which makes it optimal to maximize the run cycle until the differential pressure (DP) over the filter reaches a suitable value, approaching maximum allowed DP. However, in practice, the individual filters often show a non-constant flow rate behavior, typically a decreasing function of ...

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Optimizing filtration in filter presses through in situ measurement of cake water content

B. Fränkle*, A. Menzel, H. Aust, P. Ohorn, G. Börste; Lenser Filtration AG, Germany

Integrated sensor technology within the filter plates enhances the comprehension of the filtration process in filter presses and enables its optimization. In situ measurement of cake water content, feed pressure, and diaphragm squeeze pressure provides real-time visualization and facilitates the identification of areas for improvement. Tests were conducted on a pilot filter press, involving varying filtration pressure and different diaphragm squeeze pressures for this purpose. A sensor for measuring cake water content was positioned in the head plate (Lenser i-Plate), while additional sensors on the periphery of the filter press measured feed and diaphragm squeeze pressure.

Figure 1 illustrates an example of in situ measured data of a non-optimized filtration cycle. Through the measurement of cake water content, feed pressure, and squeezing pressure, it becomes possible to precisely delineate the different stages of the filtration process. The initial increase of the cake water signal up to a peak marks the end of the filling phase. Subsequently, a decrease in cake water content and a rise in feed pressure indicate the cake build-up. At some point the maximum possible pump pressure is reached. Ideally, this...

Furthermore, the diaphragm squeeze stage is divided into two sections: a phase of continuous cake water decrease, highlighted in green, and an avoidable extension, marked in red due to lack of optimization. By eliminating the red segment, the process can be shortened significantly, reducing cycle time.

Speaking on an industrial scale, this optimization of the filter press performance will facilitate the operation of more cycles per day and enhance plant throughput. A second optimization potential resulting from in situ measurement involves obtaining additional data. Typically, measuring cake water content is only feasible after the filter press is opened. Employing an in situ sensor allows for a thorough examination of the impacts of the different process parameters at each stage of the filtration cycle.

In conclusion, it can be stated that ...

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Study of the effect of temperature and residence time in hidrotermal condition on the filterability of biological sludge through a filter press

D. Pirini*, D. Collini, B-PLAS Sbrl; F. Kaswalder, A. Grosso, N. M. Finocchiaro, Diemme Filtration Srl, Italy

Biological sludge, a byproduct of wastewater treatment processes, poses challenges in terms of efficient dewatering and disposal in most countries. Hydrothermal carbonization (T > 180°C) is an effective technology that disrupt the complex biological matrix of the sludge thanks to thermal energy and auto-generated pressure; coupling the hydrothermal treatment with a filter press is an effective method to reduce the volume of the sludge to be disposed of.

In this study we focused on the effect of two key parameters in the hydrothermal carbonization process: time and temperature.. Finding the right balance between residence time, temperature and filtration performance is the key for an efficient process of volumetric reduction of biological sludge. The experiments were conducted over a range of temperatures (160°C – 200°C) and residence times (15min–120min).

The results show that there are lower ...

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M01 - Water Treatment

Day: 13 November 2024
Time: 09:00 - 10:15 h
Room 4

Assessment of circle-sequence reverse osmosis in high-recovery operation for brackish water reuse

Y. Lee*, W. Kang, W. Lee, J. H. Lee, M.J. Park, SK Ecoplant, Korea; J. Kim, Wenzhou-Kean University, China

In response to the increasing demand for water reuse to bolster water security, attention is shifting towards achieving not only a substantial volume but also high-quality recovered water. Membrane-based water treatment processes, especially reverse osmosis (RO), have gained widespread adoption in the water-reuse market due to their efficient removal of particulate matter, bacteria, viruses, and dissolved solids with an efficiency exceeding 99%. While RO ensures water quality, system recovery is often constrained by low water flux in RO membranes, a consequence of the tradeoff between water permeability and salt permeability. Although multi-stage RO can enhance recovery to over 85%, it complicates membrane design and raises application costs. Moreover, high-recovery operation frequently leads to membrane fouling. To address these challenges, circle-sequence reverse osmosis (CSRO) has been developed as a modified configuration of semi-batch closed-loop RO to increase system recovery rate with a simplified design and reduce fouling propensity through staged design and flow reversal operation. CSRO allows to achieve a high recovery as well as to inhibit mineral scaling and organic fouling. This study introduces the concept of novel CSRO and evaluates its performance during pilot operation. Initially, achievable recovery was examined using discharged water with a total dissolved solids concentration of approximately...

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Evaluating different pre-treatment options for produced water treatment using integrated FO-MD system

M.S. Nawaz*, N. Ghaffour, S. Soukane, King Abdullah University (KAUST); V. Gudideni, Ali-Alqahtani, Saudi Aramco, Saudi Arabia.

Background: Global produced water generation is about 120,000 MGD which contains hydrocarbons, salts, and other contaminants in huge quantities. Different process-dependent produced water streams are generated at an oil exploration site. The water-oil separator (WOSEP) recovers any remaining oil and generates WOSEP outlet stream with total dissolved solids (TDS) concentration of 92 g/L. The separated oil is desalted, producing another stream termed desalter effluent with a TDS around 6.3 g/L. Untreated discharge of produced water in abandoned reservoirs or sea can cause significant environmental and aquatic life deterioration. However, after suitable treatment, it can be reused for re-injection or other onsite applications. Forward osmosis (FO) and membrane distillation (MD) are two emerging membrane-based low-pressure water treatment technologies. FO-MD hybrid systems is proven efficient and stable in produced water treatment with identification of some key foulants like oil nd grease, sulfate, silicates and calcium. Removing these key contaminants through pre-treatment can improve the performance of the FO-D hybrid system.

Aim of the study: To experimentally identify which technique is the most suitable for the pre-treatment of WOSEP outlet and desalter effluent streams in terms of increased and stable flux, membrane chemical stability and reduced reverse salt flux.

Materials and methods: Five different pre-treatment technologies were studied including polymeric micro-filtration, polymeric ultra-filtration, ceramic ultra-filtration, electro-coagulation and ion-exchange through resins. Figure 1 shows...

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Towards total selective separation and recovery of textile dye mixtures: advances in membrane technology and environmental protection

S. Oukkass*, A. Bouftou, R. Ouchn, L. Bousskssou, M. Hlaibi, Université HASSAN II GeMEV; Y. Chaouqi, ESITH Casablanca, Morocco

The modern textile industry relies heavily on intense dyes such as methylene blue (MB) and acid yellow 61 (AY61) to imbue fabrics with a range of vibrant colors. The intensive use of industrial dyes poses a significant environmental threat to aquatic ecosystems, soils and health. Methylene blue is appreciated for its antimicrobial and anti-chemical degradation properties, while its counterpart acid yellow 61 is often not recommended for its potential toxic effects on biodiversity. In response to these environmental challenges, polymer inclusion membranes (PIMs) assisted by activated carbon have emerged as a promising solution to effectively separate and recover textile dyes from industrial wastewater. This innovative approach presents substantial progress in promoting efficient textile practices and contributing to efforts for a clean and sustainable environment. The adoption of such technologies contributes to a future where the fashion vibrant colors coexist harmoniously with the management and protection techniques of the environment and ecosystems.

In the present studies for the selective separation and recovery of MB dye from mixtures, various parameters were quantified, permeability (P) and initial flux (J0) for the membrane performances, as well as apparent diffusion coefficient (D*) and association constant (Kass) for the movement nature of the substrates and the mechanism of the executed processes (Table). The activation and thermodynamic parameters (Ea, ΔH#ass, ΔH#dis, ΔS# and ΔHth) were determined to confirm the experimental results ...

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10:15h - Coffee Break


K03 - Keynote Lecture 03

Day: 13 November 2024
Time: 10:45 - 12:00 h
Room 1

Session Chair:
Dr. Wu Chen

Formation and separation of flocculated suspensions: Good practices and challenges for laboratories and industries

Dr. Pascal Ginisty, IFTS – Institut de la Filtration et des Techniques Séparatives, France

Flocculation is a common operation for urban and industrial wastewaters and sludge treatment. Analysis and models are mainly devoted to elementary particles whereas the flocs, usually poorly known and little characterized, are the physical objects treated in separation devices. Operators of sewage treatment plants have to adapt daily the conditions to water/sludge variability but owing to a lack of knowledge on chemical conditioning mechanisms and flocs behavior, the adaptation remains usually crude and poorly mastered.

A better knowledge of their generation, properties and behavior under constraints in separation processes is required for works design and performances optimization. The presentation will review existing practices to form and measure intrinsic and behavioral flocs properties with standardized methods or original techniques, will describe particle agglomeration mechanisms and point out the importance of mixing conditions and their environment, will point out the necessity for models to take into considerations particles agglomeration and flocs break-up under constraints and the water release in the spaces between end inside flocs and the required multiscale approach.

The challenges for scientists and industrials are a better identification of key parameters at micro and macroscale ruling flocs formation and separation processes, a better quantification of constraints undergone by flocs in industrial machines, the adaptation of existing separation models to flocs properties, and the possibility to replace, partially or totally, chemical products by bio-sourced products to reduce the environmental impact of coagulation / flocculation.

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F04 - Sustainable Filter Elements and Media

Day: 13 November 2024
Time: 10:45 - 12:00 h
Room 2

Session Chair:
Dr. Lars Spelter

Leading the way to a more sustainable future for filtration through innovative solutions

S. Pigeot-Rémy*, C. Prost, Ahlstrom Specialties, France; T. Quatrano, Ahlstrom Italia SpA, Italy

Often taken for granted, the quality of the air we breathe and the water we drink is a crucial element that plays a pivotal role in ensuring our overall health and wellbeing. Poor air quality can lead to allergies, asthma, and chronic conditions such as cardiovascular and respiratory diseases (or worse). Additionally, its devastating effects can extend to biodiversity, causing significant environmental and economic losses. In this context, the sustainable provision of clean air but also pure liquids is one of the major societal and environmental challenges, now and in the future. With the increasing awareness of concerns, regulatory bodies and governments may enforce soon more stringent standards for air quality and sustainability in indoor environments, including our homes, workplaces, and vehicles. At the same time, the need for embracing sustainable technologies in all aspects of life is greater than ever.

Today, almost every industry relies on advanced and high-performance filtration to purify and decontaminate liquids and gases – and ultimately to protect people and systems all over the world, thus making our world safer and healthier. Looking towards the future of filtration, there is a clear trend embracing greener and more efficient filtration solutions. And when it comes to air filtration, sustainability involves using filter media, systems and processes that not only effectively clean the air around us but also have a positive environmental impact by reducing the carbon footprint.

In this quest for enhanced sustainability, the filtration industry relies on the expertise and insights of global leaders like Ahlstrom. Our comprehensive portfolio of specialty materials – including bio-based, synthetic, and recycled fibers – is designed and developed to help customers find the best balance between performance and sustainability across a wide range of applications. This reflects our purpose to “Purify and Protect with Every Fiber, for a Sustainable world.” And as the industry moves further into environmental changes, the integration of sustainability in our innovation strategy is not just a trend but a commitment to responsibility, shaping the way Ahlstrom develops and manufactures the next generation of filter media.

In this article, two main approaches are introduced through recent product development examples. The first approach is functional sustainability: we continuously develop effective and energy-efficient filtration products with improved performance (longer lifetime, lower energy consumption, better filtration efficiency) in order to reduce the carbon footprint of end customers. The second approach is core sustainability: we address the growing demand for fluorocarbon-free solutions without compromising the product quality and performance, and we incorporate increasing amounts of bio-sourced raw materials which improves overall sustainability along the value chain and reduce the carbon footprint of the entire process. All these projects are supported by EcoDesign and Circular Design tools in a systematic way...

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LENZING™ Lyocell enhanced fibrillation fibres provide a sustainable competitive advantage for high-efficiency filter media design

N. W. M. Edwards, M. Gallo, Lenzing Fibers Grimsby Ltd, UK

The Lenzing Group stands for the environmentally responsible production of high-quality, specialty fibers derived from the renewable raw material wood. The production process of LENZING™ Lyocell fibers is distinguished by its conversion efficiency and closed loop design, which recovers, purifies and re-uses the process solvent and process water.

With a microfibrillar structure, good thermal stability and chemical resistance, LENZINGTM Lyocell fibers are well suited for use in various types of filter media. Their cellulosic composition contributes to compatibility with cellulosic and synthetic fiber types and binders. It also means these fibres are biodegradable in soil, freshwater and marine conditions or can be used for energy recovery by incineration at the end of the product lifecycle.

Commercial applications for LENZINGTM Lyocell fiber-based filter media range from lightweight papers for teabags and coffee filters, through pleatable media for industrial and automotive filters, to heavyweight depth filter sheets for food and beverage filtration. LENZINGTM Lyocell Shortcut fibres can be fibrillated in a separate step prior to the papermaking process. These fibrillated fibers provide a unique source of sub-micron diameter fibrils through wet abrasion within a refining process. Fibrillated LENZINGTM Lyocell Shortcut fibers may be directly incorporated into filter media formulations to increase wet web strength and sheet tear resistance, or for enhancement of fine particle filtration efficiency. Recent process enhancements by the Lenzing Group have resulted in LENZING™ Lyocell Enhanced Fibrillation (EF), Lyocell fibers which required less time and energy to reach a given degree of fibrillation, saving precious cost and valuable resources.

The work in this paper aims to:

  • Outline current and future market trends in Filtration related to sustainability.
  • Discuss the latest advances in LENZINGTM Lyocell fibers production and the commercial availability of fibrillated LENZINGTM Lyocell fibers, including Enhanced Fibrillation (EF) fiber.

The test sheets were subjected to physical tests to verify basis weight, thickness and air permeability prior to measuring filtration performance according to ISO 5011, ISO 16890 and ISO 19438 test methods. Laboratory tests show that...

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Europe as trendsetter in corporate sustainability: The role of CSRD, CSDDD, filtration technologies and innovation

P. Wijns, CleverSustainability, Germany

The European Union (EU) is setting new global standards in corporate sustainability with two primary directives: the Corporate Sustainability Reporting Directive (CSRD) and the Corporate Sustainability Due Diligence Directive (CSDDD). These regulations aim to enhance transparency, accountability, and sustainable business practices, making Europe a global trendsetter.

What are the critical features of CSRD and CSDDD? CSRD is a comprehensive framework that enhances corporate reporting on environmental, social, and governance (ESG) factors, mandating companies to provide detailed sustainability reports. CSDDD, on the other hand, is a robust directive that aims to ensure companies conduct thorough due diligence on their supply chains to identify, prevent, and mitigate adverse human rights and environmental impacts.

The Role of Filtration Technologies

Filtration technologies for air and liquid are vital in achieving the environmental standards the CSRD and CSDDD set. These technologies help reduce pollution, improve public health, and ensure compliance with regulatory requirements. Air filtration technologies are essential for reducing industrial emissions and capturing pollutants such as particulate matter and VOCs, improving air quality, ensuring regulatory compliance, and providing health benefits and a safer work environment. Liquid filtration technologies are critical in removing contaminants from wastewater and process water, promoting sustainable water management practices like reuse and recycling, and ensuring compliance with water quality standards and environmental protection regulations.

The Impact on Innovation

The CSRD and CSDDD, combined with the emphasis on filtration technologies, drive significant innovation across various sectors. These directives encourage investment in research and development for advanced filtration systems and other sustainable technologies, fostering technological advancements. Innovations in new materials and air and liquid filtration methods help reduce environmental footprints and enhance sustainability. Market opportunities arise as companies that develop and implement innovative filtration technologies gain a competitive edge through improved environmental performance, and the demand for green technologies opens up new markets for filtration systems and other sustainability solutions. Furthermore, the need to meet regulatory standards fosters collaboration between industries, academia, and research institutions, facilitating knowledge sharing and accelerating innovation. Companies can adopt best practices in filtration and sustainability from each other’s successes and challenges, driving continuous improvement.

Scientific Implications, Behavioral Economics, and Market Dynamics

Filtration technologies enable systematic data collection and analysis of environmental performance, providing valuable insights for benchmarking and research. Quantitative data on air and water quality collected through these technologies allow for rigorous benchmarking and inform policymakers and regulators about the impact and effectiveness of filtration technologies. Additionally, filtration technologies influence corporate behavior and market dynamics, incentivizing companies to adopt sustainable practices. The need for compliance with environmental standards drives companies to innovate and adopt advanced filtration solutions, while enhanced environmental performance attracts investors who prioritize ESG factors, thereby influencing market dynamics.

Global Challenges and Opportunities

Adopting filtration technologies in Europe can lead to policy diffusion globally, setting benchmarks for other regions. Europe's high standards serve as a model, promoting the global adoption of similar environmental technologies, facilitating regulatory harmonization, reducing regulatory fragmentation, and supporting international trade. Ensuring compliance with filtration standards presents challenges, particularly for SMEs, which may require support to adopt and maintain advanced filtration technologies. While initial investments in filtration systems can be significant, they are essential for long-term sustainability. International cooperation is crucial for harmonizing filtration standards and promoting global sustainability, with alignment with organizations like the United Nations, ISSB, and ISO helping to promote global standardization and facilitate trade relations. The EU must continuously update and refine its regulations to reflect scientific advancements and stakeholder feedback, integrating the latest advancements in filtration technologies and environmental science and ensuring regulations remain effective and relevant through continuous engagement with businesses, civil society, and academia.


The European Union is setting new global standards in corporate sustainability with the Corporate Sustainability Reporting Directive (CSRD) and the Corporate Sustainability Due Diligence Directive (CSDDD). These directives enhance transparency, accountability, and sustainable practices. Filtration technologies are vital in meeting these standards by reducing pollution, improving public health, and ensuring compliance.

Air and liquid filtration technologies help reduce industrial emissions and remove contaminants, promoting sustainable water management. This drives innovation, fosters collaboration, and opens new market opportunities while attracting ESG-focused investors. Europe's high standards can facilitate global policy diffusion, setting benchmarks and promoting regulatory harmonization. Despite challenges for SMEs, the benefits of sustainable practices and advanced filtration technologies are essential for long-term sustainability. International cooperation and continuous regulatory updates will ensure Europe remains a global leader in corporate sustainability.

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G07 - Indoor Air Quality

Day: 13 November 2024
Time: 10:45 - 12:00 h
Room 3

Long-term stability of air-particle ionization with ZeroOzone ion-booster technology

R. Heinze*, getAir GmbH, Germany

Despite a sustained decline in pollutant emissions in Europe in recent decades, legal limits are still being exceeded, particularly in urban areas where around 90% of European city dwellers are exposed to dangerous levels of particulate matter. This exposure leads to serious respiratory diseases, lung cancer, strokes and premature mortality and shortens life expectancy in the EU by more than eight months. The average city dweller spends 90% of their life indoors, where hazards arise from emissions from building materials, furniture, textiles, mould spores and daily activities such as cooking and heating. Energy-efficient buildings exacerbate the problem as they reduce natural air exchange to minimise heat loss. Therefore, the demand for efficient and less energy-intensive methods of air treatment is growing.

One way to optimise the energy efficiency of air filtration is to use an electric ioniser to charge the particles. This charging has the great advantage that electrically charged particles improve the separation efficiency of downstream mechanical filters (electret filters) or electrical filters (electrostatic precipitators). In this way, significantly lower pressure losses and therefore energy-efficient filter systems can be realised. However, until now such electrostatically enhanced filter systems can only be used to a limited extent due to the power-dependent ozone emission and the long-term decreasing stability of the corona discharge (due to wear and contamination of the high-voltage electrodes). The wear behaviour of the electrode is the result of a complex combination of physical and plasma-chemical phenomena. These phenomena include oxidation reactions of the atomic oxygen and the emitted ozone with the electrode surface as well as ion- and electron-induced sputtering, in which high-energy particles collide with the electrode surface. These wear phenomena are also superimposed by deposits and soiling on the electrode. During prolonged operation, these effects can significantly change the electrode geometry and therefore...

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AeroSolfd – Developing filtration solutions for improving air quality at metro stations

K. Kedwell*, M.J. Lehmann, MANN+HUMMEL GmbH, C. Asbach, IUTA, Germany; S. Agathokleous, T. Moreno, IDAEDA CSIC; C.M. Casado, CARTIF, Spain

AeroSolfd is an EU co-funded innovation action developing retrofit filtration solutions as a fast track to cleaner urban air. A particular focus is on developing, installing, and testing filtration devices for improving air quality at metro stations. Per day more than 100 million people are commuting by metro. Metro networks are the backbone of the economy in bigger cities and contribute to reducing inequality by affordable transport options. However, the semi-closed environment of a metro station, in particular underground, is usually not primarily designed considering air quality and studies confirm it by demonstrating that concentrations of respirable particles in metros and their stations are high, and usually higher than those in the ambient environment (e.g., Martins et al., 2015). Providing good air quality, both inside trains and at the stations, is a key and challenging objective of metro operators. Primary local sources of particle emissions are brakes and rails. But there are many other factors influencing the air quality (e.g., the design of station, ventilation systems, trains’ frequency, etc.). Studies show that each station is different. Nevertheless, a flexible, scalable filtration solution to be installed as ‘retrofit’ at the platform would be a promising option for improving air at existing and new stations.

The 3-year innovation action AeroSolfd started in May 2022. First results can now be reported: The design of the air purifiers has been updated for use at metro stations. Emissions of metro brakes have been analyzed to find a good tracer. Air purifiers have been installed at a metro station in Lisbon. We are going to report on the progress, present and discuss the setup at the metro station in Lisbon as well as results on air quality measurements.

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Investigation of VOC and PM reduction performance of innovative porous materials to improve indoor air quality

A. Tüter*, I. S. Akgün Güldür, G. Sir, BEKO A.Ş, Turkey

Air pollution increases day by day with the growing industry and increasing population which consequently poses a threat to humans and other living beings. Considering that indoor pollutant concentration reaches 5 times higher than that of outdoors, it becomes inevitable to use devices with air purification functions and specialized filters. High efficiency particulate air (HEPA) filters are known for their particulate matter (PM) filtration efficiency of over 99.95%. HEPA filters have fibrous structures and are usually produced from glass fiber and polymers such as PP and PTFE. On the other hand, activated carbon is one of the most abundant and widely used adsorbants in terms of volatile organic compound (VOC) removal and odour capture. Apart from these widely acknowledged materials and filter media, highly porous innovative materials such as aerogels and metal organic frameworks (MOFs) display promising performances in terms of pollutant removal.

In this study, both PM and VOC removal performance of different types of aerogels and MOFs were evaluated. Silica aerogel sheets were prepared and employed as the PM removal filter to be used in an air conditioner. Subsequently, PM removal performance of filters were measured in terms of clean air delivery rate (CADR) by keeping track of the PM concentration over time according to GB/T-18801 standard. VOC removal performance of the innovative materials were conducted in a tight test chamber where methyl ethyl ketone (MEK) was selected as the model VOC source. MEK was evaporated with the help of a small fan inside the chamber and after the complete evaporation, the weights of the samples were measured to gravimetrically analyze how much of the initial MEK was adsorbed by the samples through comparison with the initial weight of the samples. PM and VOC removal performances of pristine aerogels were compared with pristine MOF via following the same test procedure. Finally, pre-determined amount of MOFs were mixed with aerogels and the overall uptake capacity of the mixture was evaluated. It was found that ...

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M02 - Desalination

Day: 13 November 2024
Time: 10:45 - 12:00 h
Room 4

Fabrication of hydrophobic clay-embedded electrospun PVDF-co-HFP nanofibrous membrane to enhance the desalination performance of highly saline water via air gap membrane

M.E. Hossain*, M.A. Azeem, T.N. Baroud, King Fahd University of Petroleum and Minerals, Saudi Arabia

Membrane distillation (MD) has great potential to be highly energy-efficient and a promising water desalination technology. In this study, we demonstrate the preparation of unmodified and synthesized hydrophobic clay-modified polyvinylidene fluoride-co-hexafluoropropylene (PVDF-co-HFP) nanofibrous electrospun membranes and investigate their performances through Air Gap Membrane Distillation (AGMD).

Different concentrations of clay particles (0.5, 1, and 2 wt%) were incorporated into the PVDF-co-HFP polymer solution to enhance the membrane’s water vapor transportation and overall desalination performance. The modified and unmodified membranes were characterized to compare their surface morphology, elemental analysis, surface roughness, crystallinity, and vibrational properties. The experimental AGMD configuration uses highly saline 7 wt% of NaCl as hot feed solution. The results displayed that the incorporation of 2 wt% of hydrophobic clay particles with an unmodified PVDF-co-HFP membrane matrix has significantly enhanced the membrane properties, revealing a high porosity >91.6% and high contact angle >143o (more hydrophobic than the unmodified PVDF-co-HFP). These favourable properties led to an improvement in the flux reaching 19.91 kg/m2h which is almost 64% higher than the unmodified PVDF-co-HFP membrane (12.16 kg/m2h) and showed an excellent salt rejection of ~100.00%.

The present study demonstrates that tailoring clay particles into PVDF-co-HFP polymeric membranes through a facile electrospinning technique holds significant promise in fabricating ...

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Enhancing boron removal efficiency of layered double hydroxides via functionalization with β-cyclodextrin for reverse osmosis applications

M.S. Khan*, S. B. Chen; National University of Singapore, Singapore.

Layered double hydroxides (LDHs) constitute a unique class of clay materials characterized by brucite-like lamellar structures interspersed with specific anions. Their remarkable efficacy in environmental remediation stems from their ability to encapsulate contaminant molecules within their layers or along their edges. In addressing the challenge of boron removal, particularly from brackish water at pH 8 where boron predominantly exists as boric acid, LDHs face limitations due to the structural similarity between boric acid and water molecules, thereby impeding conventional membrane separation techniques. In previous investigations, we explored the modification of LDHs through functionalization to enhance boron removal efficiency. Building upon our previous findings, our current research endeavors to further refine LDH modification techniques by synergistically employing tannic acid (TA) and β-cyclodextrin (β-CD). Initially, pristine LDHs underwent modification with tannic acid, followed by functionalization with β-CD. The synthesized materials and membranes have undergone comprehensive characterization to elucidate their chemical properties. Subsequently, the fabricated membrane was employed in the reverse osmosis process utilizing a solution containing 15 mg/L boric acid and 2,000 mg/L NaCl. The synthesized membrane incorporates an abundance of free hydroxyl groups, thereby enhancing the accessibility for the coordination of boric acid molecules with these hydroxyl groups. This enhancement potentially...

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12:00h - Lunch


K04 - Keynote Lecture 04

Day: 13 November 2024
Time: 13:00 - 14:15 h
Room 1

From process to operation: Digital twins for filtration

Dr. Ralf Kirsch, Fraunhofer Institute for Industrial Mathematics ITWM, Germany

When speaking of a digital twin, we usually think of a computerized, virtual counterpart to a device or process in the real world, allowing us to study and predict its performance under varying (operating) conditions. In filtration, a classical application is the computer-aided optimization of the design of a filter medium or element to reduce time and cost spent on the building and testing of prototypes.

The relevance of such a digital twin for the prediction of the filter lifetime can be seen by the many works devoted to the simulation of flow and filtration from the microscopic length scale of the nonwoven to the macroscopic scale of the element. In the context of the fourth industrial revolution (industry 4.0), digital twins interacting with the real filter device through data exchange (will) play an important role, because they offer very interesting possibilities such as predictive maintenance, automatization of optimal operation and many more.

Obviously, a digital twin must reflect the relevant properties of the real device and therefore, one of the challenges is to identify what is relevant such that the required computational resources do not prevent a beneficial use. In this talk, we look at improving digital twins of filter elements by taking a more integrated approach with the focus on the filter media. More precisely, we consider a “chain” of digital twins, representing different stages the filter medium goes through: From “birth” (fiber laydown process), over “formation” (e.g. pleating) to “professional life” (operation in the filter element).

The material property of major interest is the (non-)uniformity of the distribution of the fiber volume fraction. The fiber laydown process determines how “cloudy” the filter nonwoven will be, which influences the filtration efficiency of the flat sheet material. The pleating creates regions of compacted nonwoven material, where the flow resistance and filtration properties can differ significantly from the flat sheet. And in contrast to a quite common assumption of computer models, filter media are not rigid bodies, but they deform under the pressure of the fluid flow. Depending on the (operating) conditions, these deformations cannot be neglected in the digital twin of the filter element.

The talk presents examples of these digital twins together with the underlying models and algorithmic aspects. We will also discuss open questions and future perspectives.

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F05 - PFAS-Free Membranes

Day: 13 November 2024
Time: 13:00 - 14:15 h
Room 3

PFAS-free venting membrane from polyphenylsulfone

A. Rasmussen*, A. Schoch, T. Batt, M. Loepfe, Novamem AG, Switzerland

Venting membranes are widely used in various applications that require protection from liquids and solids while allowing air to pass through. One can find such membranes in cell phones, headlights, batteries, medical devices, or clothing. Currently performing venting membranes are based on polytetrafluoroethylene (PTFE) or other per- and polyfluoroalkyl substances (PFAS). However, the use of these substances has been heavily discussed due to their persistent nature. This is why several EU countries (including Germany, amongst others) have submitted a restriction proposal for PFAS-containing materials in 2023.Therefore, there is a strong need to develop venting membranes that are based on non-PFAS materials, without compromising their performance and functionality.

For the first time, Novamem demonstrates the production and use of a hydrophobic venting membrane based on polyphenylsulfone (PPSU). These proprietary membranes are produced by the patented slash/ process of random hard template removal, allowing the manufacturing of membranes based on a large variety of polymers. Available Novamem PPSU membranes offer comparable air flow rates and liquid entry pressures.

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SVHC and PFAS-free membrane for membrane bioreactors

A. Rasmussen*, T. Batt, M. Loepfe, Novamem AG, Switzerland

Membrane bioreactors (MBR) are gaining more and more attention to reintegrate communal but also industrial wastewater. Some of the high-performing MBR membranes are based on polyvinylidene fluoride (PVDF), belonging to the group of per- and polyfluoroalkyl substances (PFAS). However, the use of these substances has been heavily discussed due to their persistent nature. This is why several EU countries (including Germany, amongst others) have submitted a restriction proposal for PFAS-containing materials in 2023 .Therefore, there is a strong need to develop MBR membranes that are based on non-PFAS materials, without compromising their performance and functionality.

Besides the recent changes for PFAS-based materials, solvents used to manufacture said membranes are usually substances of very high concern, as defined in Article 57 of Regulation (EC) No 1907/2006. The industry has proposed alternative solvents (sometimes referred to as “green solvents”) to support this change. Nevertheless, classic membrane manufacturing by phase inversion seems to struggle in adapting their processes without compromising their membrane performance and functionality. This challenge underscores the critical need for further research and development in membrane fabrication techniques that can fully integrate these green solvents. Such advancements are essential to aligning industry practices with environmental regulations and achieving long-term sustainability in wastewater treatment technologies.

For the first time, Novamem demonstrates the production and use of a reinforced membrane based on polyether sulfone (PES), using a green, biodegradable solvent. These proprietary membranes are produced by the patented slash/ process of random hard template removal, allowing the manufacturing of membranes based on green solvents. Available Novamem MBR membranes offer superior flow rates and chlorine stability. The membrane has been tested for an extended period of time in a real-life environment...

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Towards high-efficient coalescence filtration: Alternatives to PFAS-based functionalization of media

M. Wittmar*, C. Asbach, Institute of Energy and Environmental Technology e.V. (IUTA); L. Tsarkova, B. Gerbert, J. S. Guttmann, et. al., Deutsches Textilforschungszentrum Nord-West gGmbH (DTNW), Germany

Coalescing filtration is a widely used technique in industry to remove oil from compressed air to achieve air quality suitable for production processes. Typically, filters are made from glass fiber nonwovens and represent heterogeneous media with complex permeability and capillary properties defined by fiber dimensions and media density. An important parameter for the overall filter efficiency is the saturation of the filter media and the formation of the oil film. The resulting pressure drop significantly increases the energy cost of the process.

Currently, a well-established technology is to reduce the surface energy of the fiber surface using fluorine-based formulations to provide oleophobic wetting properties. However, as of February 2023, the European Chemicals Agency (ECHA) regulates more than 10,000 perfluorinated and polyfluorinated substances (PFAS). In the near future, the use of PFAS will be banned in many sectors. Even for technologies such as coalescence filtration, where oleophobicity is essential for high efficiency, the use is under strong discussion.

Since there is basically no substitute for PFAS to achieve oleophobicity, the industry is looking for F-free alternatives to improve the separation and dewatering performance of coalescence filtration.

Previously, we demonstrated a more than 30% reduction in the differential pressure of a saturated coalescent filter medium as a result of patterned modification of the downstream filter surface with a fluorine-containing finish, which can be considered a low fluorine approach. .

The current project aims to improve the separation mechanisms by patterned coalescent filters with integrated drainage nonwoven media with chemically and topologically structured surface, so that the energetic effects (surface tension) are enhanced by topographical and topological effects. Preliminary results ...

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G08 - Energy Efficient Air Filtration

Day: 13 November 2024
Time: 13:00 - 14:15 h
Room 4

Investigation of ventilation concepts for the elimination of potentially infectious aerosol particles in relation to energy efficiency

S. Berger*, L. Springsklee, J. Niessner, Heilbronn University of Applied Sciences, Germany

Ventilation plays a critical role in mitigating the airborne transmission of exhaled virus-laden aerosol particles in indoor environments, particularly underscored by the recent COVID-19 pandemic. Strategies such as more frequent natural ventilation, higher fresh air ratios in mechanical ventilation systems, or decentralized air purification technologies have proven effective in reducing the indirect risk of infection indoors. However, when maintaining thermal comfort, these strategies also lead to higher energy consumption for heating, cooling, and air circulation. This presents a challenge, as the effort to eliminate potentially infectious airborne particles indoors conflicts with the objective of increasing energy efficiency within buildings.

To address this problem, novel approaches are required that take into account not only air quality based on CO2 concentration and thermal comfort, but also the risk of indirect infection by virus-laden aerosol particles and energy expenditure, when designing ventilation concepts for occupied spaces. In this context, we present an analytical model that can be used to assess both the spatiotemporal probability of infection based on a Wells-Riley approach and the spatiotemporal air quality based on the analytical CO2 concentration in indoor spaces. Experiments and flow simulations using a representative test aerosol that mimics infectious exhaled particles inform this model.

By combining different ventilation measures, including natural ventilation, stationary ventilation systems, and mobile filtering air purifiers, we aim to reduce the concentration of airborne pollutants in occupants' breathing zones while partially substituting fresh air with purified recirculated supply air. This approach minimizes ventilation heat transfer and mechanical energy demand while allowing for compliance with thresholds for air quality, thermal comfort, and infection probability. We vary operating conditions of ventilation measures, such as employed filter classes, air purifier locations or volume flow ratios, to assess their impact.

To correlate the impact of operating conditions on energy expenditure, we determine the analytical energy demand in a steady energy balance, assuming optimal operative temperatures for maintaining thermal comfort. By partially substituting fresh air from an HVAC system with filtered recirculated air from a mobile air purifier, significant ...

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Exploring the effectiveness of air filtration in optimizing indoor air quality and energy-saving

S. Ghaffari Jabbari*, H. Kofoed Nielsen, T. Sandnes Vehus, University of Agder (UiA), Norway

Indoor air pollution is a complex issue involving a wide diversity and variability of pollutants that threaten human health. For creating a healthy indoor environment, it is important to start with the control of indoor pollution sources. Most of the time it is impossible to control the pollutant sources, making it necessary to use filtration technologies. These technologies consume a considerable amount of energy to provide a comfortable indoor climate. This review presents a general overview of existing filtration technology, evaluating, their effectiveness in improving air quality while considering energy efficiency and economic factors. Additionally, the review provides insights into how diverse filtration techniques use energy conversion to mitigate various indoor air pollution, showcasing their advantages and limitations, and paving the way for future solutions that prioritize energy efficiency and optimal indoor environments.

The study explores the intricate relationship between filtration efficiency, pressure drops, and energy consumption in heating, ventilation, and air-conditioning (HVAC) systems. The findings reveal that while...

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Energy savings in HVAC systems with waved 3D composites

S. Daus*, Hollingsworth & Vose GmbH, Germany; A. M. Endalew, Hollingsworth & Vose, UK

Heating, Ventilation and Air Conditioning (HVAC) units utilize a significant amount of energy in our buildings, hence improving energy efficiency and reducing the cost of ownership is particularly important. The importance of energy savings is reflected globally. For example, the European Union has agreed on a set of measures to make Europe a carbon neutral continent by 2050 (1). As 40 % of the annual energy-consumption in Europe is generated in the building sector (2), it is no surprise that one set of initiatives of the European Green Deal is built around energy efficient buildings. In an HVAC system, savings can come from better fans, better heat exchange or energy efficient air filtration. In this paper, we will address solutions to improve the energy efficiency of the filtration media using novel nonwoven solutions.

Traditionally, single layer and dual layer media have been used to achieve efficiency and capacity of pocket filter media. However, for energy savings, pressure drop of the filter is the key parameter. Hence, 3D composites using waved media have been developed to reduce pressure drop and increase capacity. An example from our data analysis showed that waved 3D filter media can achieve up to 4 times higher Dust Holding Capacity (Lifetime) at 250 Pa filter element pressure drop compared to traditional pocket filter media. In summary...

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L05 - Continuous Vacuum Belt and Pressure Drum Filtration

Day: 13 November 2024
Time: 13:00 - 14:15 h
Room 2

Session Chair:
Prof. Gernot Krammer

Vibration compaction of compressible filter cakes – Achievements from the recent years

H. Nirschl*, T. Yildiz, Karlsruhe Institute of Technology (KIT), Germany


Cake filtration is a widely used process to separate solids from liquid in various sectors, including mining industry or wastewater treatment. After cake formation, a porous particle structure exists which is completely filled with liquid. To remove the remaining liquid from the filter cake, mechanical deliquoring measures can be used as an alternative to thermal drying. Since mechanical deliquoring requires 100 to 1000 times less energy than thermal drying, it is reasonable to mechanically remove the liquid from the filter cake to the maximum possible extent.


A conventional post-deliquoring method is desaturation, where further liquid is driven out of the cake pores by a gas differential pressure. Especially for fine, compressible filter cakes, this leads to cake shrinkage, which benefits crack formation. The lower flow resistance of the cracks in the filter cake causes a higher gas throughput at constant pressure difference and, hence, higher operating costs. In the worst case, a significant drop of the pressure difference occurs, which reduces the achievable residual moisture of the filter cake. So it is the goal of the investigation to show that vibration of a filter cake helps to consolidate the cake structure to ensure an efficient deliquoring and washing.


Starting with previous investigations on vibration compaction perpendicular to the filtrate flow] have been carried out on a discontinuous laboratory scale. For cake filtration in industrial applications is preferably realized in continuous filtration apparatuses such as Horizontal Vacuum Belt Filters (HVBF) to achieve high throughputs. Therefore, it is essential to verify the applicability of this technique for additional mechanical deliquoring of compressible filter cakes in an existing continuous filtration apparatus. This talk will address the transfer and scale-up of the method to an existing indexing HVBF. For this purpose, a novel modular unit for vibration compaction has been developed and will be presented.


After implementing the vibration module on the indexing HVBF, the compaction and mechanical deliquoring effect of the module on an industrially relevant slurry was investigated for different frequencies and vibration times in the continuous pilot-scale apparatus. An important aspect is particle segregation which has significant impacts on cake formation such as a longer cake formation time compared to homogeneous cakes. The talk addresses the impact of this effect on vibration compaction. Thus, dewatering results of homogeneous and segregated cakes made of the same material with a broad particle size distribution are compared. Although cake deliquoring is achievable despite particle segregation, vibration compaction is more effective for homogeneous cakes. The reason is that ...

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Development of an autonomous process for the selective extraction and filtration of metal ions from mining waste

V. Bächle*, M. Gleiß, Karlsruhe Institute of Technology (KIT); A. Voigt, K. Sundmacher, Otto-von-Guericke-University Magdeburg; N. Bajcinca, S. Hiremath, Universität von Kaiserslautern-Landau, Germany

In order to stop global warming, greenhouse gas emissions must be drastically reduced and the removal of already emitted CO2 from the atmosphere must be pursued in combination with permanent CO2 storage. In this context, carbon mineralization offers the possibility of producing permanently bound carbonates with calcium and magnesium. One source for the metals are tailings, which are dissolved by acid extraction in form of metal ions.

However, the selective extraction of Ca2+ and Mg2+ ions from the mining waste changes the particle size distribution and the bonds between the particles and thus the filtration properties, depending on the existing material composition. Another problem is the fluctuating material composition in the feed, which poses a challenge when it comes to the economic efficiency of this process. One possible solution to respond to fluctuating feed conditions is the concept of an autonomous belt filter. However, this requires not only in-situ and online process analysis, but also reduced-order models to describe the filtration properties under fluctuating feed conditions.

In this study, we present our concept of an autonomous process for the enrichment of Ca2+ and Mg2+ ions in the liquid phase. The first two steps of the autonomous process consist of the ...

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HiBar drum filters – The answer to new filtration challenges in the battery minerals and rare earth processing

J. Hahn*, BOKELA GmbH, Germany

The world is moving into a new era where energy is no longer produced on the basis of fossil fuels such as oil, coal and natural gas. The energy in the upcoming decades will be increasingly produced on the basis of wind and sun as well as nuclear power with more and more electric drives in vehicles, trains, ships and machinery in our households requiring a battery if used in areas that have no permanent connection to the grid. The metals and minerals required for electric motors are mainly copper for the winding, aluminium for the casing and iron-cobalt-nickel, neodym-iron-bor or samarium-cobalt for the permanent magnets. And the metals required for the batteries are mainly lithium, nickel, manganese, cobalt (NMC with high energy density) or lithium, iron, phosphate (LFP with lower energy density). And the demand of these elements will rapidly increase with...

Especially, elements like lithium, cobalt, neodym, samarium or other elements of the rare earth fraction appear in very low concentration in minerals and require an intense hydro metallurgical processing. This processing requires several steps of solids liquid separation steps with challenges such as extreme pH-values (<2 or >12), temperatures > 100 °C, intense wash of solids, low moisture, continuous operation, etc. Especially intense wash of solids quite often ends up in two or three steps of filtration with intermediate solids reslurry. However, this pushes CAPEX for filtration equipment to the high end and puts the realization of projects at risk.

Modern pressure drum filters such as the BOKELA BoHiBar Drum XL 18 or XL 26 are able to perform a three-stage counter current cake wash with a slurry that is fed to the filter with a temperature of up to 200 °C and solids with a d50 of down to almost 1 micron...

The design of the filter with

- A high number of individual filter segments

- A quick drainage of the liquid into the piping system to the control head

- A sharp separation of the wash liquids in the control head

- An operation with back pressure on the filtrate separators

result in reaching the target figures with only one filter unit while other filter types like plate and frame filter presses require two filters with intermediate reslurry. Or the material of construction does not allow for temperatures in the range of 100-200 °C...

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14:15h - Coffee Break


F06 - Poster Session

Day: 13 November 2024
Time: 14:45 - 16:00 h
Room 2

Session Chair:
Dr. Marco Gleiß

AGXX® – An innovative technology to prevent microbial contamination in filtration applications

T. Schwob*, M. Danz, Heraeus Precious Metals, Germany

Microorganisms, omnipresent in our daily lives, vary widely in their impact on human health. While many are harmless or beneficial, assisting in biological metabolic processes, others – including certain bacteria, viruses, and fungi – pose serious health risks, especially in water-based environments where they can multiply rapidly. Ensuring a high-quality water supply is a fundamental need for any civilized society necessitating the use of water filtration devices in various applications such as wastewater treatment or filtration systems for private households. However, these systems are susceptible to microbial contamination and biofouling. Such issues not only threaten consumer health but also reduce the lifespan of the filtration products. In the era of multi-resistant germs, enhancing water quality through innovative antimicrobial technologies and protecting filters from bacterial growth have become more crucial than ever.

AGXX is a new antimicrobial technology based on a catalytic redox cycle which leads to the generation of so-called reactive oxygen species (ROS) from water and oxygen. Additionally, formation of a micro electric field between two precious metals further enhances the antimicrobial activity.[1]

Efficacy against over 130 microorganisms including bacteria, viruses, algae, and fungi, among others silver-resistant E. coli strains, methicillin-resistant S.aureus (MRSA), or CoV2 viruses as well as the prevention of biofilm formation by use of AGXX has been demonstrated to this date.[2],[3]

The technology is commercially available in various product types, well suited for incorporation in textile filters or direct use as a carbon-based additive in form of powders, granules, and pellets. Antimicrobial activity has already been proven in various applications...

[1] Landau et al. (2017) Galvanotechnik

[2] Guridi et al. (2015) Materials Science and Engineering C 50

[3] Sobisch et al. (2019) Frontiers in Microbiology

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Filter UV-decontamination study utilizing experimental and simulation methods

J. Virkajärvi*, T. Kiiskinen, O. Mangs, S. Salo, A. Harlin, VTT Technical Research Centre of Finland Ltd; F. Elsehrawy, J. Halme, Aalto University, Finland; A. Miettinen, J. A. Ketoja, Mid Sweden University, Sweden

We investigate the UV-decontamination of surgical face mask utilizing experimental and computational methods. We measure the reduction of microbes (MS2 virus and Staphylococcus aureus bacteria) in the entire face mask and its filtering middle layer under different doses of UVC-light. To understand better the decontamination power of UV-light, particularly the roles of absorption and scattering in the mask, we performed UVC-light ray-trace simulations in physically correct mask fibre geometry obtained from the X-ray microtomography images of the mask. We observe that UV-light scattering inside the mask increases the effective radiation dose and thus the decontamination power. Even though part of the light is transmitted through the mask in one-sided exposure, radiating the mask from both sides ensures more even irradiation and thus better decontamination. In general, these results can be considered applicable and relevant also for other types of fibrous filters, e.g., in-house air-filters. In particular, the combination of X-ray tomography imaging and ray-trace simulations gives a powerful and realistic tool to investigate irradiation in filters.

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Employing poplar fibers for developing face masks

A. Güraslan*, Istanbul Technical University, Utrkey; E. Cozzoni, FreyZein-NextGen Textile, Austria

Among top ten current N95 producers, only one of them is EU-origin company. Europe needs to act to develop sustainable face masks to lead the fabric filtration industry, which will be worth in excess of 2.7 billion Euros in 2024. Currently, melt-blown polypropylene (PP) is the mainly used filtering medium in face mask applications. In this research, however; we have formulated an innovative and interdisciplinary project to develop filtration media using sustainable and antibacterial poplar fibers. Poplar trees, European black poplar, Populus nigra, are very fast-growing trees. Poplar trees are grown on an area of 76 million decares in the world to be used as raw material for industrial products such as paper, cellulose pulp and plywood. Although poplar wood is widely used for industrial purposes, poplar fibers have not been used for any industrial purposes.

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Porous metallic sinter paper: a new material for use in filtration and membrane support applications

O. Andersen*, C. Kostmann, R. Hauser, L. Heggelmann, Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM); M. Rentzsch, S. Schramm et al., Papiertechnische Stiftung PTS, Germany

A manufacturing process derived from paper technology can be used to produce a flat porous metallic material. To this end, organic fibers, fillers and additives are mixed with metal powder and the pulp is subsequently processed on a paper making machine (Fig. 1). The so-called green paper is then subjected to a heat treatment where the organic components are removed. After that, the remaining sheets are sintered at temperatures close to the melting point of the metal powder, resulting in a purely metallic porous material, the so-called sinter paper. This approach has been used for the development of different porous materials such as nickel, copper and stainless steel 316L. Using a lab scale paper making machine, coiled green paper with a length of 10 m and a width of 0.4 m has been produced. After the heat treatment, the thickness of the purely metallic porous sheets ranges typically from 200 to several hundred microns with porosities anywhere between 40 and 60 %. The pore sizes are typically in the range of several µm up to approximately 25 µm, depending on the manufacturing parameters. This contribution gives examples of different material types including some morphological data. The morphological characterization was carried out based on high-resolution µCT scans which were analyzed via the software package GeoDict (Fig. 2). Measured and calculated values of the electrical conductivity have been compared and the permeability was calculated from the µCT data. While current work focuses on applications in hydrogen technology, the newly developed material seems also to be well suited for filtration purposes and membrane support applications i. e. in CO2 capture and utilization.

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Air permeability descrepancy of non-woven synthetic fibre material

S. Baloyi*, Eskom Holdings SOC Ltd, South Africa

Eskom utilises two different types of synthetic fibre material: namely PPS (Polyphenylene Sulphide) and PAN (Polyacrylonitrile) both fibres containing a cascaded layer of (P84). These non-woven fabrics are used in coal fired boilers for particulate emissions reduction in the fabric filter plants. The fabric filter uses the sieving effect produced by filtration materials to remove suspended particles from the raw flue gas. Fabric filter bag manufactures and suppliers must produce filter bag material that conform to the end user’s specification. Air permeability is one of the most fundamental variables used for fabric filter bag selection as well as conformity to specification. A low permeability result indicates more resistance to gas passing through the filter media and a result lower than 10% of the new value is considered blinded or blocked.

Air permeability measurements of synthetic fibres varies between the coastal and in-land regions and tests have indicated significant variances with the results. This effect might be due to the difference in altitude between the various locations of the bag suppliers manufacturing sites. This research aims to test this hypothesis. The study experimentally investigates variations of air permeability measurements on a coastal and in-land region using fabric filter bag material with the same characteristic properties.

The methodology employed is evaluation of the rate of the air flow passing perpendicularly through a known area of fabric, adjusted to obtain a prescribed air pressure differential between the two surfaces. The rate of air flow is measured, and the air permeability of the fabric is determined. An in-house method derived from the standard ISO 9237:1995 Textiles - Determination of the permeability of fabrics to air as well as SANS 5265:2007 Air permeability of textile fabrics will be used the analyses.

Four laboratories are selected to participate in the study, these laboratories are situated in the coastal and in-land regions respectively. Two laboratories at in-land and two laboratories at coastal regions will be utilised. Five specimen of fabric filter bag material made up of PPS and PAN shall be prepared and analysed in these laboratories. The air permeability results shall be evaluated and compared against each other to determine the effect of altitude when characterizing a filter bag material.

The Supplier Assessment is a requirement for a comprehensive test and evaluation program that will ensure that the products used in Eskom are fit for purpose and comply with the specification. The research will assist the end users of the fabric filter bags to select fabric filter bag material appropriately and accurately with a complete characterization. The outcome of the investigation is also important in informing the design and operation of the fabric filter plant system.

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Performance optimisation of filter bag materials in Eskom’s fabric filter plants

I. Phiri*, Eskom Holdings SOC Ltd, South Africa

Fabric Filter Plant (FFP) Technology is installed in eight of Eskom’s coal fired power stations for particulates removal from the flue gas after combustion in the boiler. Eskom is one of the biggest users of fabric filters globally, with a total number of 676 818 bags currently operating in 42 boilers. The bags are manufactured according to Eskom’s bag specification. Approximately 72% of the installed bags are manufactured from polyphenylene sulphide (PPS) fibres and operate at a temperature of about 140 °C, while 28% of the bags are manufactured from polyacrylonitrile (PAN) fibres and operate at approximately 125 °C. Eskom’s bag specification was modified by blending PAN and PPS fibres with multilobal P84 (Polyimide) fibres to improve filtration efficiency. Approximately 94% of the bags in Eskom’s FFPs are blended with P84 fibres.

The performance monitoring program was introduced whereby the bags are sampled and tested during operation to study failure pattern and to identify parameters of the bag specification that need to be modified for performance improvement. The bags are sampled at 3 000 hour intervals and tested for deviation in air permeability, pH, strength and dust retention. It was observed that the bags in most power stations fail due to acid attack, reduced air permeability and high dust retention.

The performance of the bags differ according to the location of the power station, the type of coal used in the boilers and FFP design. PPS bags are expected to achieve minimum of 32 000 operational hours while PAN bags are expected to operate for minimum of 18 000 operational hours. The bags in the newly built power stations are failing prematurely below 15 000 operational while some of the old power stations are achieving or sometimes exceeding the expected operational life. In one station the bags were achieving approximately 40 000 operational hours, and after analyzing condition monitoring test results it was observed that performance of the bags could be improved by modifying the fabric specification. The specification was modified by constructing the raw gas side of the fabric into two filtration layers instead of one layer (Eskom Fabric Filter Bag Standard, 240 -53113965). The first filtration layer was constructed by ...

The second layer and the inner batt were constructed from 2.0 dtex round PPS fibres. The scrim and inner batt remained unchanged. The air permeability was adjusted from 16 ml/cm2/s to 6 ml/cm2.s at 125 Pa by needling tighter and compacting the fabric to reduce dust penetration. The operational life of the FFP increased from 40 000 to 70 000 hours with this modified fabric. For continuous improvement, the condition of the bags will be assessed at the end of life (>70 000) to identify areas of the specification that need to be modified.

Eskom also introduced trial bags program in which different filter media are tested for application in Eskom’s FFPs. The aim of the trial bag program is to identify alternative filter material that can operate efficiently in Eskom’s FFP. Ceramic filters, Laminated fabrics and various blended fabrics were evaluated for Eskom’s application...

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Computer-aided determination of the ideal filter media

M. Fuhrmann*, M. Gleiß, H. Nirschl, Karlsruhe Institute of Technology (KIT); S. Rehm, M. Müller, Spörl KG, Germany

Filtration is a widely common unit operation in solid-liquid separation and is used in processes across all industries. Filter media play an essential role in the process. Therefore, selecting the right filter media for a specific separation task is an essential step in the design of filtration processes. Due to the large number of filter fabrics available on the market, this is a complex task and is often based on experience. In addition, competing properties such as separation efficiency and flow rate make the selection difficult. For example, the pore size of a filter fabric must be as large as possible for high flow rates, but as fine as necessary for the desired degree of separation. Possible consequences of suboptimal mesh selection are lower filtrate flow rates, clogging of the meshes, and thus increased energy consumption of the filtration process. This, in turn, is directly related to an increase in resource requirements and an increase in particle loading of the filtrate. This can lead to impairment or even failure of following unit operations in the plant network.

Therefore, the aim of this work is to provide a predictive tool to support the selection of the filter mesh. Based on different characterization parameters, a model is developed using machine learning methods. This model allows a computer-aided selection of a suitable filter mesh for a given separation task. The characterization parameters investigated include the separation efficiency in terms of the degree of separation and the flow rate of different filter media. Meshes with different weave types and different geometric pore sizes were considered. In addition, the...

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Characterisation of sustainable membranes based on electrospun silk fibroin

A. Nicosia*, F. Ravegnani, CNR-ISAC; G. Sotgiu, R. Zamboni, L. Ottaviano, T. Posati, CNR-ISOF, Italy

The majority of raw materials used for filtration are not sustainable, as they are mainly plastics of fossil origin -such as polyethylene, polyester and polyamide- which are poorly biodegradable. As a result, they accumulate, rather than decompose, in the natural environment. The fate of these products is becoming an urgent environmental issue, as the case of disposable masks, recently considered as a threat to the oceans.

As an alternative, the use of biopolymer is considered a viable perspective to reduce the environmental impact of filter devices. To this purpose, we investigate the use of silk fibroin (SF) for the conception of high-performance filtration media.

In this work, SF membranes have been successfully fabricated by a green electrospinning process, which uses water as solvent. To control the viscosity of the solution, a reduced amount of polyethylene oxide (PEO) is employed, in a final ratio 70:30 with respect to the amount of fibroin. The obtained electrospinning solution is a mixture of water, silk fibroin, and PEO, resulting in a non-toxic precursor solution.

By varying the time deposition of electrospinning, we evaluated the effect of the weight factors on the filtration performance of SF membranes. Efficiency is tested by measuring the penetration of NaCl aerosols through the membranes, at a fixed velocity of 5.3 cm/sec. The pressure drop is measured by a differential pressure gauge (Testo Manometer 512). Quality factor is retrieved from pressure drop and filtration efficiency at the most penetrating particle size.

Results show a significant anti-correlation between ...

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Characterization of size and spatial uniformity of pores in fibrous and moire membranes: A computational modeling approach

E.-M. Papia*, A. Kondi, University of Athens; E. Gogolides, V. Constantoudis, D. Nioras, NCSR Demokritos; K. Ellinas, University of the Aegean, Greece

Pores play a pivotal role in the functionality of fibrous membranes, particularly in filtration applications, where their size, distribution, and connectivity directly influence performance outcomes [1]. Porous structures facilitate the selective permeability necessary for filtering particles, contaminants, and microorganisms from various media, such as air, water, and industrial fluids. The efficacy of these filters relies on the precise control and characterization of pore properties, making pore metrology an essential field of study. A

ccurate pore characterization ensures the optimization of membrane design for enhanced filtration efficiency, longevity, and reliability, underscoring the critical nature of metrological precision in the development and application of fibrous materials.

To this end, fibrous membranes can be effectively modelled using linear networks , both straight and curved [2], or lattice patterns (fig. 1), consisting of multiple layers overlaid slightly askew, which can be named Moire membranes [3], providing a framework to analyse their structural properties systematically. This dual-pattern methodology enables a thorough investigation of key pore characteristics, such as uniformity and proposes a decomposition into size and spatial contributions.

In particular, we present a comprehensive modelling and analysis approach that employs these geometric configurations to simulate and evaluate the pore characteristics inherent in various porous materials. By applying computational techniques, we can quantify pore size distributionand pore spatial uniformity, offering a detailed understanding of how these are affected, while tuning known structural parameters, such as mesh number, rotation angle, or number of fibers. The analytical tools for characterizing the spatial aspects of pore uniformity are drawn from the field of stochastic geometry [4], ensuring a solid mathematical framework. Thus, the theoretical approach presents a guide for the optimization of material design for specific practical applications, ensuring improved performance and reliability.

Application wise, nanoporous structures of hexagonal nylon mesh used for fog water harvesting are examined. Computational modelling techniques are employed to simulate the behaviour of such membranes, using hexagonal Moiré membranes under varying angles of rotation and positioning, while an analytical formula is derived to describe the influence of the number of meshes. These two approaches are compared using the Shadow Coefficient (SC) [5], a parameter that quantifies the coverage of the studied material and is directly related to membrane performance in water collection efficiency. The results are then compared with analogous analyses of images from the experimental setup.

The findings elucidate the influence of geometric patterning on the performance of porous materials, providing a robust methodological tool for designing materials with tailored pore characteristics for specific applications.

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Invest in the future of nonwoven filter manufacturing with a comprehensive suite of innovative carded & needlepunched solutions by ANDRITZ

G. Julien*, ANDRITZ Perfojet SAS, France

With ANDRITZ’s innovative solutions you can unlock the full potential of carded filter production. Our technologies are engineered to ensure web regularity and productivity, setting new industry standards in the field of inline carded filters. Opt for a single TT card to cut costs and achieve higher weights, boosting throughput at the end of line drastically.

In addition, the ANDRITZ portfolio offers outstanding patented solutions to achieve unprecedented uniformity in crosslapped processes:

  • The ProWin™ system sets a new benchmark for web weight regularity, ensuring consistent quality across your products.
  • The Battcruise system integration allows further enhancement of the fabric quality by minimizing unnecessary draft at the crosslapper exit, thus providing precise control over evenness.
  • The DF-4 Elliptica mode for producing needlepunched lightweight materials (<70gsm) at high-speed (30m/min) without compromising on product regularity & visual aspect quality.

With ANDRITZ’s technologies, you are not just investing in machinery. You are investing in a future of unparalleled quality and efficiency in nonwoven fabric production for filters, allowing you to benefit from key competitive advantages on the market.

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Upcoming Air and Liquid Filtrations

K.-J. Choi*, Clean & Science Co., USA

Due to rising levels of pollutants, and the increased emphasis on health and well-being, the global market size projections for the next 10 years seems to be doubled. Global liquid filtration market sales revenue totaled $3 billion this year and be doubled by 2033. Global Air purifiers market totaled $15 billion this year and will expand to $25 billion by 2033. Global HVAC filter market size was 4 billion this year and will expand to $7 billion by 2033.

Upcoming air and liquid filtration systems are expected to continue advancing in filter materials enhancing microorganism deactivation effectiveness, higher particulate and gaseous contaminants removal efficiency, more sustainable materials, and more energy efficient compact designs for limited spaces. It will be in incorporated with smart technology, allowing them to be controlled remotely.

Built-in air and liquid quality monitoring systems with air and liquid filtration systems such as temperature, humidity, PM2.5 particles, volatile organic compounds (VOCs), carbon dioxide (CO2) levels, and allergens become more common. Robotic application of air and liquid filters will be more popular.

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G09 - Poster Session

Day: 13 November 2024
Time: 14:45 - 16:00 h
Room 3

Experimental methods for the investigations of internal and rear-side drainage behavior in oil mist filters

R. Mandic*, J. Meyer, A. Dittler, Karlsruhe Institute of Technology (KIT), Germany

The gravity-driven drainage behavior of coalesced oil has been extensively characterized in fine porous coalescence materials, showing that oil drains in a (partially) closed film at the rear side, whereas intraporous drainage is negligible in such materials. In industrial applications, a structural support structure and a drainage layer (a.k.a. entrainment barrier) are often placed behind the coalescence material.

These components introduce additional interfaces that can alter drainage behavior, potentially leading to interfacial drainage paths along the gaps of the interface. Furthermore, contrary to fine-porous coalescers, the open porous structure of the drainage material can present an intraporous drainage path. This research aims to obtain a fundamental understanding of the drainage behavior of coalescing filters in real applications.

A novel filter chamber will be designed with partitions to distinguish between and measure the intraporous, interfacial film, and rear-side surface film drainage streams. The filter chamber requires oil outlets at different and precise positions to measure the various drainage rates. This study will investigate how the drainage behavior is influenced by the properties of the drainage material (e.g., mean pore size, thickness) and the support structure, along with process parameters (e.g., face velocities, oil delivery rate)...

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Novel high-efficiency liquid aerosol separator

G. Dwars*, C. Mehring, University of Stuttgart, Germany

This work presents a novel demister which combines the principle of a swirl or cyclone separator with the micro-impaction principle, i.e., inertial impaction on the micro-scale. The latter was already investigated by Kaiser (2020) for planar droplet-laden flows through woven wire meshes with weft and warp wires aligned perpendicularly and parallel to the flow direction, respectively.

Kaiser’s work showed, that separation performance of wire meshes can be significantly increased by a shallow inflow angle with respect to the wire-mesh plane, while at the same time only moderately increasing pressure drop across the mesh. The present work aims to synergetically combine the prescribed separation effect with that exploited in cyclone separators, i.e., centrifugal separation in swirling flows (Dwars and Mehring (2024)).

To that extend, numerical flow simulations were carried out for a 7.7 degree periodic sector of a cylindrical flow cell with prescribed swirl in the incoming axial flow, as shown in Figure 1 (left). The droplet-laden swirling gas stream is allowed to flow radially outward through a cylindrical square wire-mesh along the height of the flow cell. At its outer radius, the flow cell is limited by a wall diverting the flow in axial direction.

Simulations are based on the steady-state incompressible RANS equations with SST k-ω turbulence model (including curvature correction) and Lagrangian description of the disperse phase using a random-walk model for turbulent dispersion. Numerical solutions were computed using the - ANSYS Fluent Version 2022R1. A contour plot of the calculated velocity magnitude in a q=const. plane is shown in Figure 1 (right).

Numerical simulations show that, depending on flow cell geometry and operating parameters, low flow angles through the wire mesh can be maintained and the benefit of inertial droplet impaction can be preserved even at through-flow directions not aligned with weft or warp wires.

Experimental comparison of pressure drop and separation efficiency for a properly tuned modified separator geometry (consisting of the flow cell with an integrated swirler) and a unidirectional cyclone (with identical swirler-blading but different swirler-core and a downstream cylindrical section) were carried out. A white-light aerosol spectrometer (Palas WELAS digital 3000) was used to determine particle size distributions in the upstream and downstream flows. Information on the geometry of the two separators is summarized in Table 1. Experimental results for a mean axial inflow velocity of 16 m/s are illustrated in Figure 2. The cut size diameter x50 of the new separator is found to be 40% lower than that of the unidirectional cyclone, while at the same time yielding a pressure drop reduction of nearly 50%. In addition, the new mesh-type swirl separator is 50% shorter than the comparable typical axial flow cyclone design.

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Collection of condensed vapors from biomass slow pyrolysis processes

P. Tronville*, M.W. Riaz, V. Gentile, Politecnico di Torino; A. Facchin, C. Torri, Università di Bologna, Italy

Biomass pyrolysis can produce charcoal for several applications. For example, the “Biomet” project studies how to transform the wood waste of the furniture industry into a renewable carbon-rich char for metallurgical use.

Along with char, biomass pyrolysis produces a gas (syngas, formed by hydrogen, carbon monoxide, methane, and other incondensable) and a condensable liquid. Upon cooling, the latter yields an ultrafine aerosol whose separation is required to obtain a clean gas, reduce environmental pollution, and turn it into a resource whenever possible. The liquid obtained from slow pyrolysis (also called wood vinegar) can be considered a high-value by-product in the preparation of biochar by biomass pyrolysis. As a natural fungicide, wood vinegar has great potential to control plant disease, achieve more sustainable agriculture, and avoid the massive use of pesticides.

We present some experimental results obtained employing a slow pyrolyzer operating with a closed-loop principle to produce metallurgical char and slow pyrolysis luquid and relatively clean syngas. The FumeCatch reactor adopts an innovative cooling-down principle and a cyclone to maximize the separation of condensed vapors. It cools down suddenly the pyrolysis fumes, mixing the hot flow with a recirculated cold fraction. This way, we can study the effect of the cooling and cyclone collection efficiency on yield and composition in the pyrolysis liquid. Aerosol collection efficiency was quantified, showing cyclone geometry’s and operating parameters’ important effect on the collection efficiency.

Quantifying and analyzing this new technology’s prototype output showed some promising results. The biochar yield ...

Water constitutes most bio-oil, accounting for 67% by mass; the remaining 33% comprises various chemicals (acetic acid, levoglucosan). According to the results...

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Microscopic in-situ-investigation of the loading process in real filter media for a holistic view of the entire filtration process

J. Ciesielski*, Q. Zhang, University of Wuppertal, Germany

A continuous filtration process that starts with a new, particle-free filter medium usually goes through the following phases: The initial depth filtration in the given filter medium, the clogging phase in the given filter medium and the cake-forming filtration on the surface of the filter medium. Until now, these phases have been described using different modelling concepts, which make a holistic view of the entire filtration process difficult.

In a new holistic view of the entire filtration process, the traditionally distinct phases are to be described with the aid of a coherent model. According to this model, particle separation takes place during the entire filtration process in two coexisting filtering systems: In the case of a fiber layer as a filter medium, a fiber packing represents the one filtering system. All particles deposited in and on the fiber packing are regarded as the other coexisting filtering system, in which all these particles can be described together in the form of a granular-bed.

Model calculations can be carried out on this basis. An important aspect of this modelling approach is the investigation and corresponding description of the particle quantities separated by the two filtering systems. These assigned quantities of the separated particles by the respective filtering systems change with the filtration time both in their absolute quantities and in the form of a ratio.

Suitable experimental investigations are carried out to verify the corresponding model calculations. In microscopic in-situ investigations, serial images of the continuous loading process in real filter media are taken, which are used to document the changes in the loading status in small steps. The desired information is to be obtained by subsequent image analysis. The first results...

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Prediction of particle dynamics before and after deposition on single filter fiber using CFD-DEM simulation

J. Wieremiejczuk*, C. Mehring, University of Stuttgart, Germany

Numerical simulations can aid in the development of more efficient air filters, not only by increasing separation efficiency and reducing air-flow pressure drop but also by enhancing filter loading capacity thereby increasing resource efficiency. However, in order to correctly determine time-varying performance parameters, an accurate representation of the filter media structure and a sufficiently accurate physical numerical model are required.

In the present work, particle deposition on a single filter fiber (representing the smallest unit of a fibrous filter media) is investigated. A two-step simulation process is used based on the coupled CFD-DEM approach; the latter employing OpenFOAM-8 as flow solver and well-established DEM contact models, which include adhesive/cohesive force interactions and a suitable set of DEM model parameters for the investigated particle/fiber system. In the first step, the flow field around the fiber and deposited particles is solved in a resolved fashion using the immersed-boundary (IB) method.

From this, the force and moment vector acting on each deposited particle due to aerodynamic interaction is computed by integrating viscous stresses and pressure over the particle surface. This information is used in the second step in which the deposition of particles (newly admitted to the flow field) on the existing fiber/particle structure is computed. The particles are propagated within the already computed flow field (via one-way coupling) while taking into account contact forces between all particles (free or deposited) and between particles and fiber. Aerodynamic forces acting on the free particles are computed using a simple drag-model whereas aerodynamic forces (and moments) acting on deposited particles are retained from the previous step. Particle-particle and particle-fiber interactions are solved directly by the employed DEM algorithm. Subsequently, the first step is repeated including now the newly deposited particles.

Using the prescribed two-step procedure, the deposition of polystyrene particles on a single filter fiber is investigated at various Stokes numbers in the inertia and interception regimes. Considered is a straight fiber under cross-flow conditions with particles being admitted to the gas stream at low volumetric concentration.

The present investigation shows that, depending on the Stokes number different morphologies of particle deposits result. Predictions are found to be in good agreement with experimental observations. More importantly, the present numerical results provide important insights into the dynamics of deposition formation not captured by other simplified approaches such as the frequently employed “stick on first contact” model for particle/particle and particle/fiber interaction. For example, simulation results for the case in which particle dendrites are formed reveal the ...

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CFD-DEM study of submicron particle deposition on nanofiber structure: particle aggregation and bridging

S. Gangani*, C. Mehring, University of Stuttgart, Germany

Nanofiber media have shown great potential as a filtration material, both for surface and depth filtration, outperforming traditional fibers in energy efficiency and filtration performance. Due to their large specific surface area by volume, nanofibers significantly increase the chances for smallest aerosol particles to adhere to the fiber surfaces, thereby achieving high filtration efficiency for particles of the Most Penetrating Particle Size (MPPS) at minimal pressure loss.

The deposition behavior of submicron particles on nanofiber structures remains an active area of research. Understanding this phenomenon is crucial for optimizing the performance of nanofiber filter media, such as enhancing their dust holding capacity while minimizing pressure loss across the filter.

In previous numerical studies, numerous authors modelled particle deposition on nanofibers based on the assumption that a particle predicted to collide with a fiber or an already deposited particle will adhere to the fiber/particle (so called "stick-on-first contact" model). For submicron-size particles, this assumption, i.e., no particle rebound upon initial contact might be acceptable. However, the assumption of "frozen deposition", which neglects the movement, dynamics and interaction of the deposited particles, is not able to accurately predict the formation of particle dendrites or agglomerates [1][2].

Once a sufficient number of particles has been deposited, detachment of particulate aggregates or agglomerates can occur, even in the case of submicron-size particles [1][3][4]. While this phenomenon is difficult to observe experimentally, it can be studied by means of numerical simulations using a calibrated set of DEM model parameters while resolving the flowfield around each particle.

Accordingly, the present investigation employs a four-way coupled and fully resolved CFD-DEM simulation methodology based on the Immersed-Boundary (IB) method, to investigate the deposition of submicron-size particles on a representative nanofiber structure while allowing for detachment and re-entrainment of particles and particle agglomerates. Figure 1 depicts initial simulation results reveal different phases of the deposition process, i.e., initial deposition of particles on bare fiber (Fig. 1A), formation of particles agglomerates (Fig. 1B), and bridging between these agglomerates (Fig. 1C), eventually leading to clogging of the filter medium...

Crossing of the nanofibers plays a crucial role in the observed “bridging” phenomena between deposited particle structures. The particle bridges act similarly to individual nanofibers by providing additional surface area for further particle deposition. This phenomenon can significantly influence ...

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Raw gas conditioning utilising the deliquescence and efflorescence properties of salt particles

D. Horst*, Q. Zhang, E. Schmidt, University of Wuppertal, Germany

The aim of optimising the operating behaviour of surface filtration is to maximise the filtration time for dust separation. This is achieved by a slow increase in pressure drop during filtration and a low residual pressure drop after regeneration. These parameters can be specifically influenced by raw gas conditioning. The effect is improved energy efficiency and longevity of the filter system.

A positive influence on the operating behaviour is possible, for example, by increasing the cohesion in the cake layer for improved regeneration. The influence of gas humidity on cohesion and regeneration is known from the literature. However, the complexity of the influence of gas humidity on particle bindings and regeneration only allows targeted influencing to a limited extent. Reinforced bindings between the particles in the cake layer with increasing humidity can be considered favourable. A concomitant increase in the adhesion of the cake layer to the filter medium, on the other hand, is to be categorised as disadvantageous. The concept presented here utilises the deliquescence and efflorescence properties of salt particles to increase cohesion without necessarily increasing adhesion.

As part of the study, the influence of hygroscopic salt particles in the dust cake on the operating behaviour of surface filters was analysed using a filter test rig in accordance with VDI 3926-1. The test rig allows each filter medium to be subjected to a defined mass concentration of a dispersible powder. Furthermore, it is possible to additionally filter airborn dry salt particles and to influence the raw gas humidity by modifying the test rig.

The aim of the investigation is to determine whether the operating behaviour of surface filters is actually improved over a longer process duration when this conditioning concept is used. Based on screening and standard tests carried out, evidence was provided of a significant improvement in cake detachment due to favourable process conditions. In addition to determining ...

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Influence of pleated filter media on the operating behaviour of surface filters in a pulse-jet-cleaned test-rig

J. P. Knisley*, J. Meyer, A. Dittler, Karlsruhe Institute of Technology (KIT), Germany

Surface filters are used in various technical processes to separate particles from a particle laden gas stream. The particles are mainly separated on the surface of the filter medium and on the surface of the already formed dust cake. A main focus in the operation of surface filters lies on the particle emission and the stable operation of the filtration plant.

Besides widely-used flat filter media (e.g. bag filters), folded (pleated) filter media can be applied to increase the theoretical filtration area. When applying pleated filter media or pleated filter elements (e.g. cartridge filters), certain problems can occur during operation, such as insufficient regeneration or an unstable operation of the filter. These problems can mainly be attributed to the pleats of the filter media or the pleating process itself.

The pleating process can lead to differences in media permeability and thus a homogeneous flow through the entire media is not possible. The inhomogeneous flow can result in velocity gradients between the pleats and lead to a loss in effective filtration area. Besides the arising problems due to manufacturing, the filter operation can be influenced by certain geometrical aspects. An increase in the pleat density (pleats per area) results in an increase in theoretical filtration area, but the effective filtration area does not follow the same trend. This is due to a few factors, such as insufficient regeneration of the pleat bottom. The insufficient regeneration leads to blockage of a certain filtration area and as a result to a reduction of effective filtration area. The loss of effective filtration area increases the mean filtration velocity and leads, assuming a Darcy pressure drop model, to an increase of pressure drop. The increase of pressure drop and the blockage of pleats can hinder stable filter operation.

The main focus of this contribution is the experimental determination on the influence of pleating and of different pleat densities on the operating behaviour of filter media in a filter media test rig ....

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Reducing energy costs in air filtration with the patented Kappa Waveline® bag filter

R. Mülleder, T. Witzler*, Kappa Filter Systems GmbH, Austria

Bag filter systems play a crucial role in various industries by providing an efficient and reliable method of separating contaminants from production processes. These systems are essential for maintaining clean air in environments where dust and other particulate matter are generated. In bag filter systems, exhaust air from various processes is fed through flexible bag filter elements, which effectively separate and capture dust emissions, ensuring a cleaner and safer workspace.

The patented Kappa Waveline bag filter can be used to optimize existing or newly planned bag filter systems.

The Kappa Waveline® bag filter has 25% more filter surface area, supported on the patented Waveline® support basket with the installation size of a standard bag filter.

The increased filter surface area leads to a lower filter surface load at the same volume flow and thus to a reduced pressure loss. The result is significantly reduced energy consumption, in some cases by 30-60%, and thus lower operating costs for the filtration of emissions.

The 25% increase in filter surface area also supports the cleaning effect and reduces the number of cleaning sequences required. This improved cleaning leads to significant savings in compressed air.

These two effects can reduce the operating costs of both new bag filter systems and existing bag filter systems while maintaining at least the same cleaning efficiency.

Alternatively, the extended filter area can be used to increase capacity without structural measures or extensions, thus helping to better comply with current and future limit values.

The effectiveness of this new type of bag filter design can be demonstrated both by empirical measurements in practical use and by scientific analyses carried out by the Institute of Air Handling and Refrigeration in Dresden (ILK Dresden).

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Assessment of high wear resistant FFP bag filter materials for Eskom application

A. Moganelwa*, Eskom, South Africa

Two new Eskom Power Stations have a total of 12 boiler units of the same design by the same Original Equipment Manufacturer (OEM). All the commercially operating boiler units make use of a Pulse Jet Fabric Filter Plant (PJFF) for particulate emissions abatement. However, the high differential pressure issues, coupled with excessive erosion began to be experienced during the first year of operation and have not yet been corrected at these sites.

This has resulted in filter bag failures and consequently unit outages for bag replacements as well as high emissions. The installed PJFF bags were expected to remain operational for 36 000 hours before needing replacement. The effect is that the filter bags fail to reach the three to four years’ expected bag life and are currently averaging a bag life of about 12 months. Full generation load is frequently unattainable due to the PJFFs and the fabric filter bags are failing with unusual frequency. This poses insecurity in production and power supply resulting in financial loss and environmental risk.

Mechanical wear and abrasion of fabric is a kind of wear experienced by fabric filters during utilization. Abrasion is the eroding away of fabric fibers or fiber surface material through moving contact between the fiber and dust particles or adjacent fibers. There are mainly two forms of abrasion, the two body or three-body abrasion. Fiber-to-fiber rubbing or fiber-to-particle collision are two-body systems.

As a measure to investigate possible improvement of plant performance, fabric filter materials that are not traditionally used within the Eskom fabric filter fleet are being considered for trials. A project has been initiated to identify high wear resistant trial bag materials to provide interim operational relief by reducing bag failures. The objective is to establish whether alternative bag options may provide operational relief. This urgent research undertaking is required to fast track the process of obtaining a solution to the high erosion condition experienced in the PJFFs.

Eskom utilises high temperature fabric with the base fibre being Polyphenylene Sulphide (PPS) while other units utilise low temperature fabric with the base fibre being Polyacrylonitrile (PAN). The potential high wear resistant material that are being tested include Para-Aramid Needle Felt Fabric, Novates® Fabric Treatment On Needle Felt Fabric, Resiltes® Fabric Treatment On Needle Felt Fabric and Pyroguard® Fabric Treatment On Needle Felt Fabric.

The intention of the test is not on filtration performance but rather proving abrasion resistance; the overall air-to-cloth ratio is expected to be influenced negatively. Each alternative trial bag type is to be tested in one compartment in the first two rows of the Cells to assess performance in the highest wear zones and to limit potential impact on the air-to-cloth ratio. Trial fabric filter bags are to be installed and experimental data collected over a period of a minimum of one year; sampled every three months or up to bag failure.

All trial bag types are to be installed in different Cells during the same period to ensure that the same operational environment is experienced by all bag types. To provide reliable trial results, the PJFF plant will need to be appropriately operated and maintained in accordance with the relevant procedures during the trial. It is anticipated that the benefit of possible longer filter bag life will outweigh the potential marginal increase in differential pressure introduced by the trial filter big materials being observed.

Although the test work is still in early stages, the first batch of results are expected by the end of July 2024 and the testing will be concluded at the end of 2025.

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Comparative analysis of needle-felt and hydroentangled filtering media for nanoparticle removal: efficiency and longevity in industrial air filtration

A. C. Vieira, F. A. Lima*, M. L. Aguiar, Federal University of São Carlos, Brazil

The emission of ultrafine particles into the atmosphere is a mounting global issue, closely tied to economic development and the rapid expansion of urban areas. Enhancing and refining equipment to extract nanoparticles from the air has emerged as a critical area of research. These inhalable particles pose severe health hazards, potentially inducing various illnesses and fatalities. Consequently, there is an urgent need for efficacious particle removal methods to foster sustainability in industrial practices and alleviate the effects of air pollution. In this context, the bag filter emerges as a paramount device, owing to its prevalent utilization, attributable to its heightened efficacy and adaptability across diverse configurations and operational scenarios. The effectiveness of this equipment hinges significantly upon the integrity and inherent attributes of the employed filtering medium. The fibers of the filtering medium can be of natural or synthetic origin, and the manufacturing technique and surface treatment also impact the filtration efficiency and lifespan of the filtering medium. The appropriate choice of fiber material for a specific application requires various characteristics such as chemical resistance, high-temperature resistance, moisture resistance, particle concentration, medium permeability, relative cost, and more. This work focused on filtering media manufactured using needle-punched and hydroentangled techniques, analyzing both new and 4-year-old filtering media to evaluate their efficiency in nanoparticle collection. For this purpose, characterizations of the filtering media and filtration tests were conducted. Needle-felt is a process in which fibers are mechanically entangled by piercing the web with barbed needles. On the other hand, the hydroentanglement process uses extremely fine, high-speed water jets instead of needles to entangle the fibers. The pressures of the hydroentanglement heads typically range from 0.5 to 25 MPa, with the jets arranged in lines along the head.

The Scanning Mobility Particle Sizer (SMPS™) spectrometer was utilized to conduct the filtration tests and analyze the nanoparticle collection efficiency. This nanoparticle measurement device can accurately measure the size distribution of submicron particles in the air. It combines electrical mobility classification with individual particle counting to provide nanoparticle concentrations in discrete-size channels. The equipment used is housed in the Environmental Control Laboratory of the Department of Chemical Engineering at the Federal University of São Carlos.

Observations revealed that the ....

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Optimization of a stairmand's cyclone separator for reduced energy consumption

J. Oranje*, J. Janssen; John Crane Indufil, Netherlands

Stairmand's cyclone separators are highly valued in multiple industries for their exceptional effectiveness in separating solid particles from gas streams. Their effectiveness arises from the vortex created within the cyclone, enabling the separation of particles through centrifugal force. Nevertheless, the formation of this strong vortex motion produces a significant drop in pressure throughout the device. Cyclones with lower pressure drops are essential in applications where energy consumption is a major concern. This work explores the use of computational fluid dynamics (CFD) and design of experiments (DoE) to optimise a Stairmand's cyclone separator with the goal of minimising energy consumption.

This study utilises Ansys Fluent as the simulation platform for the CFD simulations. The Reynolds stress turbulence model is employed in conjunction with second-order numerical schemes to improve the accuracy of the simulations. The CFD simulation results for the base case are compared to experimental data obtained by Hoekstra using laser Doppler velocimetry (LDA) and pressure drop measurements. The outcomes of the CFD simulation fall within the expected range of experimental error.

The DoE involve varying several key dimensions of the Stairmand's cyclone separator. The dimensions encompass the overall height of the cyclone, the height of the cylindrical section of the cyclone body, the diameter of the vortex finder, the height of the vortex finder, and the cone tip diameter. A total of 28 simulations are conducted. The dimensions in these simulations are varied using the face-centred central composite design methodology.

The investigation indicates that the diameter of the vortex finder is the most significant factor influencing the pressure drop in a Stairmand's cyclone separator. In contrast, the remaining parameters have a significant smaller impact on the pressure drop. In order to assess the overall impact of the dimensions, a response surface methodology, in conjunction with the screening method, was utilised to determine the most optimal design. As a result, the optimal design succeeds in achieving a 40% decrease in pressure drop compared to the original Stairmand's cyclone separator.

In order to assess the effectiveness of the optimised design, a physical test specimen is manufactured using additive manufacturing and then evaluated on a specialised test rig. The experimental results show a strong correlation between ...

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Experimental study on carbon black layer break-up in a gas cleaning model filter channel during its regeneration

O. Desens*, J. Meyer, A. Dittler, Karlsruhe Institute of Technology (KIT), Germany

Cross-flow filters are used in exhaust gas after-treatment sytems of modern combustion engines to separate ash and soot particles from the exhaust gas stream. The filter consists of parallel porous channels positioned lengthwise in the exhaust system with alternately blocked ends. The particles are deposited in the inlet channel and form a layer while the gas passes through the porous filter wall to the outlet channel.

The ash and soot particulate layer deposits can lead to unfavorable operating behavior. For example, the pressure loss of the filter increases with increasing layer thickness. The filter must therefore be regenerated regularly (continuous passive C-NO2 or discontinuous active O2 regeneration), whereby the hot exhaust gas oxidises the deposited soot particles.

The break-up of the particulate layer is a crucial process that depends on the temperature and the velocity of the exhaust gas, as well as the composition of the layer and the reactivity of the soot. The influence of temperature and velocity has already been sufficiently investigated.

However, the impact of the particulate properties and their reactivity on the resulting ash deposition patterns following the regeneration of the particulate filter remains uncertain. Studies on soot particle sizes have shown a correlation with high reactivity. E-fuels and biomass fuels can also produce different types of soot with different reactivities and dispersities.

In this study, the layer-break up of Carbon Black as reactive particulate material during the regeneration of the filter is investigated to observe the fundamental processes and transport of agglomerates in cross-flow filters. To achieve this purpose..

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Transfer of field conditions to laboratory tests for HEPA filtration in smart cabin air filter systems for vehicles - Stationary tests under reproducible conditions

E. Hallbauer*, M. Hamele, MANN+HUMMEL Innenraumfilter GmbH & Co. KG; C. Krautner, T. Heininger, T. Siegele, MANN+HUMMEL GmbH, Germany

In recent years, the focus on air quality and its impact on human health has become increasingly prominent. Efficient filtration for vehicle cabins (Cabin Air Filters) is considered as more and more important.

A Smart Cabin Air Filter System has been developed to provide drivers with the best possible protection from pollutants in the car cabin. This system includes up to three different filtration stages: a pre-filter, a HEPA filter and optionally a state-of-the-art cabin air filter in the air conditioning system. Additionally, the system is equipped with particle sensors to measure PM2.5 concentration inside the vehicle and in the ambient air, as well as CO2 sensors to monitor the CO2 levels inside the car. These sensors control the proportion of fresh air and the operation of the HEPA filter to achieve the best air quality in the cabin while optimizing energy consumption.

The development of suitable filtration materials for this purpose should not only be based on laboratory tests according to DIN 71 460. Additional field tests are essential to achieve optimum results for the development of efficient particle filtration. Thus, an electric demo car was equipped with such a system to prove its functionality and effectiveness in the field.

Proof-of-concept studies in vehicle air conditioning, especially for comparative tests of suitable filter materials, are strongly dependent on a stable size distribution of the ambient air aerosol in order to ensure comparable conditions for the tests. However, the ambient conditions in road traffic are highly variable, even on the same route and stable weather conditions, which significantly limits comparability.

To build a bridge between standardized laboratory tests with monodisperse aerosol according to DIN 71 460 on filter elements and tests in the air conditioning system or filtration unit of a vehicle in the field, tests with the Smart Cabin Air Filter System were carried out in the vehicle in a climatic chamber. These stationary tests were conducted with simultaneous measurements of PM2.5 and ultrafine particle concentrations.

For this purpose, an artificial aerosol with a similar size distribution compared to the ambient aerosol was generated. Many years of experience from field tests in various driving situations formed the basis for this artificially generated aerosol with a mixture of sodium chloride (NaCl, many very small particles, but hardly any particle mass) and ISO fine dust A2 (high number of larger particles, high particle mass PM2.5 / PM10). The aerosol was supplied into the test chamber ....

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G10 - Poster Session

Day: 13 November 2024
Time: 14:45 - 16:00 h
Room 4

Development of a plant-based filter for the exhaust air of parking garages

S. Schumacher*, U. Sager, B. Schunke, C. Asbach, Institute of Energy and Environmental Technology e.V. (IUTA); H. Schreiter, C. Schade, Niedersächsische Rasenkulturen NIRA GmbH, Germany

According to the world health organization, air pollution is currently the greatest environmental risk to human health and is associated with around 7 million premature deaths each year. According to the German Federal Environment Agency, traffic is a primary contributor to poor air quality, especially in urban areas. Although legally binding limit values have to be met at official measurement stations, particularly in places where the exhaust air from ventilation systems of parking garages or metro stations is discharged without being filtered, higher levels of pollution can locally occur. There are no clear rules on how to deal with air pollutants in these areas, but there is a great need for efficient mitigation measures.

Biological air purification with plants has various advantages over technical systems. One of these are lower prices compared to the acquisition and operational costs of technical systems. In addition, certain pollutant groups can be partially degraded and metabolized by plants instead of just being stored. In an urban context, there are other positive effects of planted systems. These include for example the retention of rainwater, a climate-regulating effect and an increase in biodiversity. Finally, the biodegradability of the plants leads to a more sustainable circular economy...

Plant-based filters such as moss walls have been partially implemented in the past in urban areas. However, their efficacy was rather low especially due to the fact that the polluted air did not pass the filter structure, but was just in diffusive contact with the surface. Furthermore, the filtering materials could not be installed near the source of the pollutants, but typically on sidewalks, where concentrations were already strongly diluted. Thus, the aim of the publicly funded project BioLu is to develop a plant-based filter which can be used to clean the exhaust air from parking garages, which has been shown to contain a large variety of particulate and gaseous pollutants, mainly originating from the vehicle exhaust as well as tire and break wear. The filter shall be capable of being retrofitted to existing ventilation exhausts and directly penetrated by the exhaust air in order to maximize its efficacy.

An efficient plant-based filter medium needs to be constructed from at least four different layers: ...

In a first step, suitable individual layers for all stages of the filter were tested with respect to their filtration efficiency and air flow resistance. The results were fed to a self-developed calculation tool to predict the most promising candidates for a layered structure. Those combinations were then tested under realistic flow conditions to find the best compromise between filtration efficiency and pressure drop. The media were tested under dry conditions as well as fully saturated with water since both states can occur in the later application. First results show that the optimized layered structures can filter at least ...

In the next step, the project partner NIRA will establish large trial plots with the optimized combination of the materials and plants. The best procedures for laying the vegetation carrier on the field for pre-cultivation as well as for care, irrigation and harvesting will be investigated. Cuttings from the plant-based filter medium will then be exposed in a custom-built test rig to typical outdoor conditions (i. e., sunlight, rain, different temperatures, etc.) while a continuous air flow is passing through it like in the later application on the ventilation exhaust of a commercial parking garage. Changes in the filtration efficiency and pressure drop as well as the resistivity of the plants to these conditions will be regularly monitored.

The project BioLu is supported by the Federal Ministry for Economic Affairs and Climate Action (BMWK) on the basis of a decision by the German Bundestag.

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Smartgreen – accounting the ecosystem-performance of urban greenings

M. Kaul*, G. Reznik, E. Schmidt, University of Wuppertal, Germany

There is currently growing appreciation for the positive impact of urban green infrastructure in society and politics. However, reliable figures are needed to justify the design of green living spaces.

The metrological proof of a significant reduction in the concentration of fine dust in the ambient air through plants was achieved through our own preliminary work on a laboratory scale. In practice, the use of the classic upwind-downwind measurement is difficult due to frequently occurring unstable wind conditions.

A possible solution is the use of a large number of cost-effective, freely programmable, interconnected multi-sensors. The sensors are distributed around an area to be assessed. They independently determine their role in the upwind-downwind system depending on the wind direction. Using this setup, the ecosystem-performance of the plants in the area is calculated.

In order to test the project idea on a laboratory scale, a height-adjustable test facility was designed and built in-house with different planting from Helix Pflanzensysteme GmbH.

The focus was on the question of the accuracy and repeatability of the measurement results obtained with smart multi-sensors. The evaluation of the operational performance of the low-cost multi-sensors developed by HANZA Tech Solutions GmbH compared to the professional reference devices was carried out in the laboratory facility in the presence of test plants.

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Are you getting realistic fab performance data? Chemical filter performance is a function of challenge concentration

R. Srivastava*, F. Belanger, J. M. Lobert, Entegris Inc, USA

AMC filters are the first line of defense in commercial operation cleanliness and a key factor to ensuring high productivity. Activated carbon filters are widely used to remove a variety of low concentration chemical contaminants from commercial operations. It is difficult and unviable to test developmental filters at real-world concentration levels, which is why filter developers or independent labs test them under accelerated conditions. In the absence of standards for filter test concentrations, performance claims can vary widely from vendor to vendor, making it difficult for the end user to compare and understand the capabilities of various filters for fab applications.

In this study we show the impact of testing filters at various concentrations and the understanding of the filter performance consequently and why an evaluation is conducted at specific lower concentrations is more effective.

The HVAC industry often tests filters at concentrations as high as 100 parts per million (ppm, 10‑6). Many AMC filter vendors test filters (or potentially only adsorbent samples) at con­cen­tra­tions between 3 and 100 ppm, the ISO standard 10121-1:2014 suggests a range of 9-90 ppm, all far above real-world applications, which might be as low as a few parts per billion (ppb, 10-9). In other words, those applications are a factor of 1000-100000 below test concentrations. Filters being evaluated at 100 ppm vs. 1 ppm can significantly skew the understanding of the filter performance in terms of lifetime or capacity.

Controlled filter testing for single chemicals at varying concentrations shows the impracticality of performing tests at high concentrations much higher than the actual environmental concentrations. However, there are certain models that can, to a certain extent, predict performances at lower concentrations based on results at higher concentrations. These models, too, are limited, and the accuracy of measurements at single digit ppb levels is questionable.

Filtration solutions are often deployed without accurately knowing the contamination challenges of the environment to be protected. This is usually done to either implement a solution as quickly as possible, or to minimize cost by using pre-defined and readily available off-the-shelf solutions. However, this approach neither assures an efficient contaminant removal nor does it optimize cost of ownership. An inexpensive filter, which is replaced often, may have a higher cost of ownership over time than a customized, more expensive solution that has a greater capacity and longer life. Considering the high cost of the ...

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Models need validation: Filter tests as a foundation for a computational model predicting performance of AMC filters

A. Chakraborty*, F. Belanger, P. Cate, R. Srivastava, J. M. Lobert; Entegris, Inc.


A wide variety of process conditions and parameters influence the design of high-performance gas phase contamination control solutions such as filters to remove airborne molecular contamination (AMC). AMC filters play a pivotal role in removing harmful contaminants from air streams in commercial operations, to protect humans, products and processes. Proper filter pleat designs maximize lifetime of the filter and provide lower costs of ownership. However, it is difficult to obtain filter performance experimentally at very low contaminant concentrations due to long test times, high experimental cost and technical limitations.

Virtual prototyping using computational fluid dynamics (CFD) can minimize these limitations. The link between AMC filter performance and a predictive, numerical model is validation through testing. A numerical model is only as good as its verified performance. Physical measurements are essential to provide a sound basis, to which the model can be tuned, before it is able to extrapolate the physical measurements to calculated data.

This study will demonstrate an approach that involves validation and prediction of the removal efficiencies of AMC filters at low contaminant levels required in many industrial applications such as SEMI cleanrooms. The application introduces ...


In our test setups, the AMC filter is positioned in a laminar air flow zone inside a wind tunnel. The pollutant test gas is introduced in the upstream airflow. The filter is then challenged with the test gas at controlled concentrations, flow rates & test conditions. The test gas is measured in both upstream and downstream locations to measure the filter performance. Fig. 1a is a sketch of the test set up, Fig. 1b shows the model of a single layer pleated filter.

Activated carbon was chosen as the adsorbent and toluene was chosen as proxy organic contaminant with initial upstream concentration of 1 ppm. A 2D representative transient CFD model was developed with a goal to predict AMC removal at low parts per billion (10-9, ppb) level, as the ability to measure AMC at those test levels is important to understand behavior in ...


An unsteady 2D CFD pleated filter model was developed by ANSYS Fluent for a specific air flow rate with toluene as the contaminant. The flow was laminar and the model was based on gas adsorption processes in a porous adsorbent bed. Modeling pressure compared well with experimental values. Moreover, the flow profile offered spatial and temporal resolution of the flow which is critical in assessing local flow uniformity profiles of filter systems. The models were able to predict and validate filter adsorption capacity. Figures 2 captured the transient contaminant mass fraction progress at three different time stamps (5, 111 and 236 hours), respectively. Red and blue indicate the saturated and unused parts of the media...


The design of high-performance gas filtration and purification products critically rely on the sensitivity of adsorption performance to a variety of process parameters, which are often difficult to know in advance of product design. Due to the constraints of conducting experiments, a CFD methodology was developed to predict adsorption behavior and filter capacity of specific AMC pleated filters. Results indicated that ...

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Investigations on cathode air filters under realistic operating conditions

C. Haynl*, MANN+HUMMEL Innenraumfilter GmbH & Co. KG, Germany

Fuel cells are basically considered as a green technology addressing the high demand for a sustainable and climate friendly mobility. Without the use of fossil energy, fuel cells provide electrical energy by the electrochemical reaction of oxygen (O2) of the environmental air with hydrogen (H2) of the storage tank in the vehicle yielding pure water as the final product. However, since environmental air comprises a wide variety of different gases, some of them negatively affecting the functional performance and the life time of fuel cell stacks, the incoming air must be selectively filtered before entering the fuel cell stack. Basically, air filtration makes use of adsorbents that capture target gases by physisorption and chemisorption, both depending on environmental influences, like relative humidity (i.e. water molecules), air temperature and gas concentrations. In terms of cathode air filtration, the interplay between temperature, water molecules and gases and their interaction with the adsorbent is poorly understood under long term conditions, but mandatory for developing tailored filtration materials. Especially, gaseous air pollutants, such as ammonia (NH3) and sulfur dioxide (SO2), were shown in the past to have a negative impact on the functional integrity and on the life time of fuel cell stacks.
In this study, the gas concentrations of ammonia and of sulfur dioxide as well as the environmental air temperature and relative humidity should be continuously monitored for a long period of time, thereby receiving a sophisticated image of environmental conditions. Therefore, dedicated sensors will be installed into a container that is located in a highly frequented street in Ludwigsburg, Germany. Furthermore, besides detection of environmental conditions, a gas adsorption filter, intended for protection of fuel cell stacks, will be additionally mounted into the same container and the ammonia and sulfur dioxide concentrations after the gas filtration step, i.e. on the downstream side of the filter will be detected in situ as well. The results of this approach will enable...

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Experimental analysis of a jet-based direct mixing process for solid state battery cathode production

J. Witte*, University of Wuppertal; V. Kolck, Technical University Berlin; H. Kruggel-Emden, Technical University Berlin; E. Schmidt, University of Wuppertal, Germany

Solid state batteries (SSB) are considered a promising future technology in the field of energy storage. In contrast to conventional lithium-ion batteries, they use solid materials instead of liquid electrolytes, which can lead to a higher energy density, improved safety and a longer lifetime. To this end, a jet-based direct mixing process in the gas phase for mixing, coating and agglomeration of cathode materials for SSB was proposed and realised to improve the homogeneity and electrochemical properties of the battery materials. In the method used, the various particle systems lithium iron phosphate (LFP), carbon black (CB) and lithium halide (LIC) are dispersed in the gas phase. The materials are then brought together as particle-laden aerosol jets in a turbulent mixing zone in which the different primary particles can interact with each other and form hetero-agglomerates. The microstructures produced in the process are analysed using scanning electron microscopy in combination with focused ion beam (SEM-FIB) and the resulting material functions are characterised by measuring the electrochemical properties (e.g. electronic/ionic conductivity, specific capacity). Furthermore, a laser light diffractor and a cascade impactor are used to determine the particle size distribution (PSD) of the materials. In addition, the gas phase process is analysed using a CFD/DEM approach in order to investigate process details that are not accessible experimentally using numerical simulations.

In experimental work, the influence of various process parameters on the mixing and structuring of the cathode material is investigated to optimise the existing process and finally to link ...

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Dust emission from bulk material handling – Comparison of experimental to model results

M. Weidemann*, E. Schmidt; University of Wuppertal, Germany

Dust emissions from bulk material handling are difficult to calculate. In this study, a Bulk Immission Ratio (BIR) is introduced, which results from experimental wind tunnel studies. These findings are interpreted using a model, published by Schulz et al. [1].

For the experiments dry lime stone with a bi-modal size distribution (1st mode 4.7 µm, 2nd mode 955 µm) is used as bulk material. 4 kg are dropped from different heights, resulting in different impact velocities. The BIR describes the ratio of the dust mass measured in the air flow to the material mass in the 1st mode.

The model calculates the dust dispersion ratio (DR) - the ratio of dust released upon impact to dust (20 µm lime stone, 5 %wt) primarily adhering to a single dropping particle (1500 µm steel ball) - for different impact velocities and plate materials.

Similar to the modeled DR, the measured BIR first rises, followed by a plateau around 7 m•s-1 and a further sharp increase. This paper discusses the experimental results in the context of the model predictions...

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Adhesion force measurements between metal spheres and calcium carbonate powder

N. Woschny*, E. Schmidt, University of Wuppertal, Germany

In order to improve a numerical model for bulk solid investigations calculating dust emissions when handling bulk materials [1] adhesion force measurements were carried out for the used reference material. This reference material represents a bulk solid in its main parts, the fine fraction and the coarse fraction.

Here, the coarse fraction is represented by metal spheres (diameter of 1500 µm) and as fine fraction a calcium carbonate powder (x50,3 = 19.5 µm) is used. Since, the determination of the adhesive force between these two fractions is not trivial, measurements were performed. The aim was to identify the adhesive force between a metal sphere and the calcium carbonate powder in order to improve dust detachment functions at a single particle level [2]. However, it turned out that ...

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Development of a low-pressure-drop air filtration system based on turbulent diffusion

T. Taibi*, L. Fiabane, L. Blondel, G. Nesen, D. Heitz, INRAE - OPAALE; L. Del Fabbro, Ampere, Group Renault, France

Air pollution is a major problem that severely impacts human health. Inhaling high concentrations of particulate matter (PM) is linked to various diseases, making this issue of central importance. To filter this particulate matter, filters use two primary types of filtration mechanisms: mechanical filtration and electrostatic filtration. The former relies on fluid flow dynamics and mainly uses diffusion, inertial impaction, gravitational sedimentation, and interception to trap particles. The latter leverages electrostatic interactions to attract and capture particles. It can either utilize the electret properties of the filter media, which diminish over time, or employ an external energy source to maintain electrostatic attraction and filtration efficiency. An efficient and optimal filter should balance particle trapping efficiency and low-pressure drop to ensure effective filtration performance without incurring significant energy costs. Another common challenge with most filtration systems is clogging. Each time the filter is clogged, it needs to be replaced, which has a significant environmental impact and incurs substantial time and financial costs.

In this sense, developments in filtration technology are ongoing, focusing on improving filter materials, optimizing the balance between filtration efficiency and pressure drop, and extending the lifespan of filters. The current study focuses on the last two elements: optimizing the balance between filtration efficiency and pressure drop, and increasing sustainability. This paper presents the early stages of developing a sustainable filter, using only mechanical filtration, mainly turbulent diffusion, and generating low-pressure drop. The filter uses vortex generators to enhance turbulent diffusion and transport particles towards collecting media.

Vortex generators have been previously employed for particle deposition enhancement [Zhang et al. (2022), Lai et al. (2001), Zhang, Jin, Nunayon & Lai (2020), Xu et al. (2020)] and are shown to enhance the deposition of particles ranging in size from sub-micron (i.e., PM0.1 and PM1) to multiple micrometers (i.e., PM2.5 and PM10). In the current study, we start by conceiving novel vortex generators. We characterize the flow downstream of the conceived vortex generators by analyzing the flow structure and identifying the main turbulent structures responsible for the particle transport using particle tracking velocimetry (PTV) (Fig.1). Next, we evaluate the optimal positioning of the vortex generator with respect to a wall parallel to the airflow and representing the filter media. The vortex generator is placed in two different configurations: 2mm upstream of the wall and directly over the wall so that the leading edge of the vortex generator is aligned with the leading edge of the wall (Fig.2). We identify the optimal positioning through the flow topology, the evolution of the vortex intensity, and the drag force generated by the vortex generator in the different positions. We finally evaluate the efficiency of an early-stage filter based on the vortex generators. The tested filter has dimensions of 140 mm (L) x 100 mm (W) x 140 mm (H). Its efficiency is assessed in terms of particle trapping and pressure drop. Particle trapping is evaluated through particle counting upstream and downstream of the filter using aerosol spectrometers. Pressure drop is evaluated through pressure measurements upstream and downstream of the filter with pressure sensors.

The preliminary results show that ...

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High performance nanofiber media for HVAC and clean room application

J. Gao*, NFT Purification Technology Inc, United States

Nanofiber Technology has been in the frontier of materials technology for filtration. It is well-know now that nanofiber is an excellent choice for Industrial dust collection, Gas Turbine Air Inlet filtration and Engine Air Intake filtration system. As we continue our pioneering work in nanofiber technology, our latest development of nanofiber for Cabin Air, HVAC and Clean Room further demonstrate more potential of our nanofiber technology. We will present the test results of these high performance nanofiber media, which show significant advantages over the conventional media such as glass fiber, melt blown and electrostatic media, PTFE membrane, in performnace reliability , energy saving and evironmental friendly aspects.

For example, our F9 Nanofiber media have the pressure drop of 23Pa comparing to 64Pa for glass fiber media at 5.33cm/s flow velocity, the dust loading capacity of our nanofiber medi is comparable with glass media. The filter made with our F9 nanofiber media has pressure drop of 75Pa comparing to 135Pa for glass fiber media at 3400m3/h flow rate. Our E10, E11, E12 nanofiber media have the pressure drop of 45Pa, 60Pa, 110Pa comparing to 113Pa, 157Pa, 200Pa for glass fiber media respectively, their dust loading capacity are comparable with their glass media counter parts as well. We also went further to HEPA and ULPA level media, our H13, H14 and U15 nanofiber media have the pressure drop of 150Pa, 210Pa, 250Pa comparing to 283Pa, 335Pa, 380Pa for glass fiber media respectively.

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Comparison of different classifier techniques for determining the mpps of high efficiency air filters

S. Payne*, J. Symonds, Cambustion Ltd. UK

Background: Electrical mobility techniques such as the Differential Mobility Analyser (DMA) have been used for many years by aerosol scientists to classify particle size, and their operation for filtration measurements is covered in ISO 29463 (high efficiency air filters) for determining the most penetrating particle size (MPPS) of a filter sample. Since 2016, classification by a particle’s aerodynamic diameter is possible using the Aerodynamic Aerosol Classifier (AAC), which uses rotating concentric cylinders with a controlled sheath flow to induce known centrifugal and drag forces on each particle sampled. Crucially, the AAC holds the advantage of operating independently of particle charge. This means there is no need to condition the aerosol charge state for classification as with the DMA, which is designed to transmit only singly charged particles (generally a fraction of the particle population) yet larger, multiply charged particles with the same electrical mobility may also pass. The AAC consequently offers significantly higher transmission efficiency, and its output is truly monodisperse. These advantages may be important for precise size-resolved measurements for filtration efficiency required in ISO 29463 and future standards.

Aim: Evidence of limited discrepancies in particle penetration measurements between the DMA and AAC was previously presented at FILTECH (Payne et al., “A New Methodology for Measuring Filtration Efficiency as a Function of Aerodynamic Diameter Using a Monodisperse Aerosol Source”, FILTECH 2018). The present research explores scenarios in which these discrepancies significantly worsen due to multiple charging artifacts, depending on the position of the DMA setpoint relative to both the peak of the input aerosol size distribution and the MPPS of the filter. This can result in incorrect reporting of the MPPS and local and integral filtration efficiencies.

A neutraliser device (usually containing a radioactive source or X-ray emitter) is mandatory in many filter testing standards to ensure the media are challenged with particles possessing an equilibrium charge distribution; examples were considered in this study where the input aerosol contains few charges, and the neutraliser was omitted from the filter testing set-up. This may be of significant benefit considering resources available at testing locations, and health and safety regulations.

Method: An AAC and a DMA were used back-to-back to measure particle penetration through flat sheet media samples of high efficiency air filters certified according to EN 1822 and ISO 29463. In tests with the AAC, results were compared with and without a Kr-85 neutraliser device between the classifier and filter sample, while with the DMA, results were compared with and without an impactor at the classifier inlet. The particle charge state of the nebulised Di-Ethyl-Hexyl-Sebacate (DEHS) test aerosol was also characterised.

Results: It was found that multiple charging artifacts in the DMA output can have a substantial effect on ...

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Air and particle leakage through face seal by wearing different FFP2 masks

D. Stoll*, D. Misiulia, S. Antonyuk, University of Kaiserslautern-Landau (RPTU), Germany

Particle-filtering face masks are designed to protect against various (droplet) infections, such as COVID-19 and others. The viruses that settle in the respiratory tract of an infected person become airborne through fine infectious droplets when sneezing, coughing, or speaking, but also when breathing itself, and can thus be inhaled by other people.

Face seal leakage plays a significant role in estimating the protection efficiency provided by face masks. Thus, there is a risk to be infected with a certified face mask. This work aims to quantify the air and particle leakages through face seal for three different types of FFP2 face masks. This was realised using Computational Fluid Dynamics (CFD) simulations.

To reveal the spots where main leakage occurs, a Sheffield test head fitted with three face masks of different shape (Fig. 1) was scanned using a microcomputed tomography (µCT). The tomographic images showed that the greatest leakage zones are located in the vicinity of the nose. Based on the obtained form (µCT) geometries, computational meshes were generated for CFD simulations.

Particle-filtering face masks are designed to protect against various (droplet) infections, such as COVID-19 and others. The viruses that settle in the respiratory tract of an infected person become airborne through fine infectious droplets when sneezing, coughing, or speaking, but also when breathing itself, and can thus be inhaled by other people.

Face seal leakage plays a significant role in estimating the protection efficiency provided by face masks. Thus, there is a risk to be infected with a certified face mask. This work aims to quantify the air and particle leakages through face seal for three different types of FFP2 face masks. This was realised using Computational Fluid Dynamics (CFD) simulations.

To reveal the spots where main leakage occurs, a Sheffield test head fitted with three face masks of different shape (Fig. 1) was scanned using a microcomputed tomography (µCT). The tomographic images showed that the greatest leakage zones are located in the vicinity of the nose. Based on the obtained form (µCT) geometries, computational meshes were generated for CFD simulations.

Particles were then simulated in addition to the air flow, using sodium chloride in a size range from 10 to 500 nm. Simulations showed that ...

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L06 - Poster Session

Day: 13 November 2024
Time: 14:45 - 16:00 h
Room 1

Session Chair:
Prof. Ioannis Nicolaou

Solving the filtration problems of sedimentary phosphates

E.-S. A. Abdel-Aal*, Central Metallurgical Research and Development Institute (CMRDI), Egypt

This review study was carried out to summarize the filtration rates of phosphoric acid from different sedimentary phosphates. In addition, different additives applied for solving the low filtration rate of some sedimentary phosphates are reported. Continuous leaching of phosphate with sulfuric and recycled dilute phosphoric acids using Dihydrate process was applied on industrial scale. Enhancing the filtration rate was applied using different additives and/or increasing the filter speed.

The obtained results are compared with the filtration rates from different international standard phosphates from Florida and Morocco. In industry, better filtration rate of phosphoric acid means higher production as well as less capital and operation costs. Chemical techniques for enhancing the filterability are reaction with the suitable surface–active agent or mixing with a poly acrylamide polymer just before filtration while the physical technique is related to decreasing the cake thickness via increasing rotation speed of filter under the standard applied vacuum.

The applied additive is depending on the type and nature of phosphate. For the Tunisian phosphate concentrate, the filtration rate was increased from an average of ... to an average of ... ton P2O5/ with addition of poly acrylic acid polymer.

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Modelling of filtration properties of representative standards of tailings based on quantitative phase analysis

M. Carpenito*, G. Cruciani, University of Ferrara; A. Grosso, F. Kaswalder, Aqseptence Group Srl, Italy

The large demand of mineral resources and large-scale mining operations produces a great deal of waste. One of the most important environmental considerations at any mine is how to manage these large volumes of waste so as to minimize the long-term impacts and maximize any long-term benefits. One category of mine wastes that can be produced is tailings: a residual slurry of fine particles and water in variable concentration. The process that reduces the impact of these large volumes of tailings is the filtration.

Dewaters the slurry changing its physical characteristics and making it a solid-behave material while recovering liquid phase that can be send back to the process. Filter-press is one of the most popular equipment for these purposes. Tailings dewatering decreases pore water and spaces and reduces the volume and potential toxicity of seepage and residual waste material results less reactive.

Features of filtration plant and tailings must account for the mineralogy of waste material. Some studies showed how types and contents of clay minerals had an impact on the filtration process changing the behavior of material. Ma et al. found that clay minerals affected the dewatering of coal slurry. Filtration tests showed that the presence of small amount of kaolinite and montmorillonite caused a significant reduction in the filtration velocity and porosity, and a great increase in the average specific resistance [1]. Grosso et al. investigated the effect of small contents of smectite on filterability of a slurry [2]. All samples studied where smectite mineral is present, even in small concentrations (less than 1%), were characterized by low filterability.

We develop, for the first time, quantitative relationships between the mineral phase contents and the filterability parameters. We prepared several standards according to the classification of fine-grained clastic sedimentary rock units. These samples are representative of tailings that can be collected from different sources. The main minerals that we mixed in different concentrations were quartz, carbonates and clay minerals, swelling and non-swelling, such as smectite and kaolinite. Some samples are composed by one type of clay mineral, others are composed by both types of clay minerals to point out the impact of each clay mineral on filtration.

The filtration tests were performed in a Nutsche Filter as well as in a small-scale filter press. Both devices belong to Diemme Filtration, one of the leading specialists in the field of solid-liquid separation for industrial processes. We obtained values for each standard of specific resistance of cake and time of filtration. These parameters were correlated with qualitative and quantitative mineralogical characteristics of different samples.

We highlighted the effects of each type of phase, in particular of clay minerals, in certain concentrations on filtration properties. We found that the average specific resistance of cake increased with the content of smectite.

High resistance means high time of filtration, low velocity of filtration, and consequently increased Capital Expenditure (CapEx), i.e., filter press and its ancillaries sizes, and Operating Expenses (OpEx), i.e., energy demand for equipment operation. Predicting the...

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Flux recovery of wire mesh filter elements by self-cleaning in filtration of magnetite

E. Strand*, R. Salmimies, Sofi Filtration; T. Kinnarinen, Lappeenranta-Lahti University of Technology LUT, Finland

The mining industry needs effective separation methods to recover fine metal and mineral particles from different streams formed during the mining and ore beneficiation processes and to treat various process waters. Filtration of very fine particles (smaller than 10 µm) is challenging due to blockage of the filter media. Traditional filtration systems need to be cleaned or even replaced when the filter media is blocked. This consumes time and money and increases the environmental load in many ways. There are some membrane filtration applications using backflushing as self-cleaning, but they are less suitable for the required scales of the mining industry.

The objective of this study was to investigate how well the filtrate flux could be restored by the self-cleaning method of the Sofi Filter®, that uses ultrasound and backwashing, in the filtration of fine magnetite at two different feed concentrations. The Sofi Filter® is a high velocity filter unit which can be operated either in cross-flow or dead-end modes using most commonly stainless-steel filter elements with nominal pore sizes down to 0.3 µm.

Magnetite powder (D50 2 µm) was mixed with water to form suspensions of 50 and 500 mg/l. The magnetite suspensions were filtered in dead-end mode with the self-cleaning Sofi Filter® with stainless steel wire mesh filter elements of nominal pore sizes of 0.3–5 µm. The self-cleaning is conducted by ultrasound and then backflushing the detached solids out of the system with filtrate, thus forming the reject. The applied feed pressure during filtrations was 1bar on average. The flux was over 30 m3/(m2h) in the beginning of the filtration.

The flux decline during filtration of magnetite was rapid; the flux dropped as much as 91 % during the filtration of magnetite at 500 mg/l feed concentration (Fig. 1). The higher the feed concentration, the faster and greater the flux decline was during filtration.

The self-cleaning was able to restore the flux fully (Table I). Even with the higher feed concentration the initial capacity was restored by self-cleaning. Particle retention during the filtrations was 40–60 % at 50 mg/l feed concentration and 50–85 % at 500 mg/l feed concentration. Elements with smaller pore sizes yielded higher retention, as is to be expected. Low feed concentration combined with very fine particles is a true separation challenge, which can be observed as relatively low retention values achieved from the filtration with 50 mg/l feed concentration.

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Filtration characterisation of leather-fibre wastewater

R. Boumda Tayong*, M. Mortazavi, University of Bedfordshire, UK

The treatment of industrial sludge has been going on for a while now and there exists various treatment methods and techniques which differ in terms of financial (device, process, etc…) and practical (space and treatment volume) constraints. The discharge of industrial waste often results into harmful agents that negatively affect our environment and lifestyle. Leather treatment finds many applications to our daily life and its manufacturing process makes it one of the most important sources of pollution to the environment.

The present work deals with the filtration characterisation and dewatering techniques applied to an industrial sludge made of leather-fibre particles. The raw sample was collected from leather factory and was tested. The study focuses on characterising particles’ physical and geometry properties obtained from the sedimentation rate, centrifuge machine, particle size and spectrophotometry measurements. Particle size analysis of the raw sample showed that...

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Correlations between the pore size and filtration efficiency of nonwoven filter media

M. Ängeslevä*, E. Pattyn, I. Struzynska-Piron, APTCO Technologies; A. Sobolewska, D. Dutczak, POROMETER, Belgium, L. Sharaf, IB-FT GmbH, Germany; C. Chowings, R. McLellan, Air Techniques International, UK

The pore size of any porous filter medium is one of the essential factors influencing the success of a filtration process. This parameter determines what can or cannot pass through the medium, dictates the minimum particle size a filter can remove, and undoubtedly affects the flow rate. The pore size correlates with the filtration efficiency of a filter medium – the larger the pore size, the lower the filtration efficiency. However, such a correlation is rarely supported by experimental data and described by any empirical equations. Therefore, the main goal of the presented work is to accomplish the following tasks: 1) to measure the pore size and air permeability of various types of nonwoven filter media with a capillary flow porometer; 2) to measure the filtration efficiency (penetration and resistance) by an automated filter tester; 3) to find and investigate the correlations between the pore size, air permeability and filtration efficiency.

12 nonwoven filter media samples from various suppliers were tested in this work. The scanning electron microscope was used to investigate the morphology of the studied samples. POROLUXTM Cito pressure scan porometer was used to measure the pore size and air permeability, PorefilTM was used as the wetting liquid and shape factor 1 was applied to the pore diameter calculations. ATI 100X Automated Filter Tester was used to determine the penetration and resistance of two aerosol reagents, such as salt and paraffin. Moreover, three different flow rates - 32, 50 and 75 l/min – for the tests with paraffin were tested.

The porometry measurement results revealed that ...

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Effect of drain layer properties on droplets formation during the separation of dispersed oil from water using coalescing filters

A. Krasinski, M. Stor*, W. Piatek, Warsaw University of Technology, Poland

The separation of O/W dispersions is an important operation in many industrial processes related to water treatment technologies, e.g., to meet discharge limits to the environment or comply with technological standards for the recirculated water. Due to their advantages, coalescence separators have been widely used for the deoiling of water, especially for the separation of secondary dispersions and small-sized droplets, which do not settle down and are spontaneously separated by gravity.

The coalescence that takes place when fluid flows through a filter element means the merging of droplets into larger ones. Many factors affect the efficacy of the process, which are related to operating conditions, physicochemical properties of liquids and the design of fibrous filtration material, including both structure and surface properties. During experiments, the detrimental effect of oil film stretching instead of large droplets formation on the outlet from the drain layer was observed at certain conditions, which significantly affected the separation efficacy. This research aimed to determine the correlation between process conditions and material properties and the structure of the dispersed phase (oil) on the outlet.

The first series of experiments were conducted for two types of nonwoven filter native polymer material – polypropylene (PP) and polyamide 6 (PA6), which were fabricated using the melt-blow technique. The separation efficacy was significantly affected by differences in the form the oil droplets are detached from the filter element. In the case of polypropylene nonwovens, the formation of foam-like structures was observed, which subsequently broke. This caused a decrease of the separation efficacy due to the release of fine oil droplets on the outlet. For polyamide nonwovens, large oil droplets were detached from the outlet layer of filter, and they were easily separated by gravity. These phenomena are...

Although the PA6 media possesses inherent surface properties more suitable for the oil from water separation, the PP is much cheaper and easier for melt-blow processing, including the manufacturing of high-efficiency structures made of fine fibers. Therefore, a modification of the outlet layer made of polymer was considered to improve the drainage. The fibers were coated with various metallic layers using the magnetron sputtering technique, which was proved to be suitable for thermally unstable polymers such as PP.

To verify the effect of treatment and obtain a qualitative measure of surface properties, the material wettability with the oil and the water was determined by measuring the static contact angle or kinetic of liquid transport at the capillary rise test. Moreover, the coating was analyzed using...

The experiments of the oil separation from water were carried out in a test tig, in which the emulsion was created by a single pass of injected oil through a centrifugal pump. Depending on the pump speed different size distribution of oil droplets was obtained (two pump speeds corresponding to 40% and 80% of the maximum were applied). The flow rate was controlled independently of the pump speed by throttling using the membrane valve, and was equal to 50, 100 and 200 L/h, while the oil concentration was set constant and equal to 2500 mg/L.

The results confirmed that ...

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M03 - Poster Session

Day: 13 November 2024
Time: 14:45 - 16:00 h
Room 5

Dynamic optimization of a dual-membrane-based UF-RO water treatment plant powered by PV-T panels with integrated co-use of heat and electricity

Q. Burgi*, E. Ndiaye, S. Dehez, B. Delahaye, L. Escobar, TotalEnergies; S. Serra, J-M. Reneaume, S. Sochard, Laboratoire de Thermique, Energétique et Procédés (LaTEP), France

The relationship between water and energy resources is complex and interdependent, commonly referred to as the water-energy nexus (WEN) [1]. The demand for freshwater and energy is increasing, which has led to concerns about the United Nations Sustainable Development Goals (SDG). The SDG 6 (Clean water and Sanitation) and the SDG 7 (Affordable and Clean Energy) are particularly threatened [2], [3]. Global population growth will have a significant impact on energy and water demand and will place significant strain on both resources[2].To address these challenges, integrated and smart management of water and energy resources is crucial at every scale, from the national to the industrial plant scale. Water reuse or recycling system with low environmental impact has transitioned from being a choice to a necessity. In this context, TotalEnergies has deployed a pilot-scale water treatment platform (SWAP: Sustainable Water Platform), a dual-membrane-based ultrafiltration and reverse osmosis water treatment powered by PV-T panels with integrated co-use of heat and electricity. Such platform aims to assess the synergy potential between energy generation and water treatment processes. The SWAP pilot also aims to demonstrate that all available water sources on or near TotalEnergies’ sites can be used (recycling or reuse) as an alternative to traditional water sources, with low CO2 direct emissions and environmental impacts. The present work aims to develop a digital twin of SWAP before considering operational optimization.

For membranes performance and fouling modeling purpose, Resistance-in-series model[4] is chosen to represent the hollow fiber Ultrafiltration skid dynamics facing different operating conditions such as various flux and water qualities (from treated wastewater after biological treatment to collected rainwater). Solution-diffusion model[5] coupled with the film theory is assumed for reverse osmosis skid modeling. Models’ predictions are compared to SWAP pilot experimental data for validation.

To operate a water treatment plant powered by renewable energy and make the most out of it, it is pertinent to rely on an optimization problem formulation[6]. Optimization techniques have been widely applied in multi-energy systems based on the water-energy-nexus[7], [8], [9]. Yet, in water treatment, the focus has been mainly on optimizing desalination, with limited integration of environmental dimension. The present study explores also SWAP dynamic offline operational optimization. A special focus over the low-grade fatal heat revalorization by filtration skids is assessed. The medium-term dynamic optimization aims to maximize treated water production while minimizing operational cost and environmental impacts. Optimization parameters are the raw water quality, on-site water needs and weather log data. The optimization variables are the skids feeding flux. Expected optimization results are the system optimal operating trajectories over 3-5 days’ time horizon. This typically includes ...

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Development of a forward osmosis process using fine particles

K. Kitamura*, T. Mori, Hosei University, Japan

Desalination of seawater is one of the methods used to produce fresh water. There are various methods for desalination of seawater. One of them, positive osmosis, which consumes less energy, has been attracting attention in recent years. When solutions with different osmotic pressures come into contact through a membrane, water molecules move from a solution with low osmotic pressure to a solution with high osmotic pressure. Forward osmosis is a method of concentrating and separating solutions using this osmosis phenomenon. Recently, in this process, it is the subject that create a driving solution of osmosis phenomena (Draw solution: DS) that have high osmotic pressure and can be easily separation. In this study, we attempted to develop a forward osmosis process using fine particles and a DC electric field to solve the above subject. It is well known that fine particles generate high osmotic pressure in water and can be used as a solute in a draw solution. We had also reported that the particles can be separated by sedimentation by applying a DC electric field to the slurry. Therefore, in this study, we combined these two elements to establish a positive osmosis process.

The slurry used as the draw solution was prepared using silica as the particle and ion-exchanged water as the solvent. The amount of water absorbed by the silica slurry was calculated from the volume change and its performance was evaluated. The volume change of the draw solution was recorded every 3 hours after the start of water absorption. The mass transfer flux density of water was calculated from this volume change. In the separation test, a DC electric field was applied using a carbon electrode to the draw solution after the volume change had stopped. The voltage of the DC electric field kept constant and the direction of DC electric field changed over a period of 30 seconds.

The average value of the mass transfer flux density of water in the test was 149.3 (g m-2 h-1). This value was larger than in our previous study. This is considered to be due to the use of smaller particles than in past studies, which resulted in

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The miniMBR® reliably treats wastewater to all effluent quality standards

M. Galimberti*, KET LLC, USA

The miniMBR® reliably treats wastewater to all effluent quality standards, including BOD, TSS,

total nitrogen, total phosphorous, disinfection, and even stringent water reuse standards. Using

the latest instrumentation and controls as well as our robust UF membrane followed by stateof-the-art disinfection processes, the miniMBR® system is guaranteed to meet all regulatory requirements.

• miniMBR® was designed to surpass the strict nitrogen and phosphorous effluent limits dictated by Chesapeake Bay restoration programs. Developed by a team of experienced engineers and manufactured in Owings, Mills, Maryland.

• miniMBR® utilizes unique air/water hydraulics to produce reuse-quality effluent using the lowest energy in its class.

• miniMBR® specifically targets high loadings and accentuated diurnal flow variations common with decentralized land development. Innovatreat’s remote control miniSCADA™ system in combination with thoughtful mechanical design features greatly benefit the operators of these small-scale projects.

• miniMBR® aquaMINE™ evolved from our standard design and has been further developed to meet today’s strict water reuse requirements. On-line water quality monitoring and robust membrane integrity assure the highest quality reuse water.

Innovatreat is dedicated to solving wastewater treatment and recycling challenges of decentralized communities and the built environment with innovative modular solutions that optimize the use of energy and chemicals while minimizing waste.

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Effect of back filtration infusion on solute removal performance in intermittent infusion hemodiafiltration

T. Kiguchi*, A. Tanuma, A. C. Yamashita, Hosei University, Japan

Hemodiafiltration is a trend of blood purification therapy for end-stage kidney disease patients in most European countries and in Japan. In intermittent infusion HDF (I-HDF), a part of dialysate is infused intermittently to the blood during treatment. Recover of the solute permeability may be expected with the infusion of dialysate by back filtration across the membrane. In our previous study, more effective recovery of solute removal performance was achieved by generating back filtration intensively around the areas where fouling was severely formed. Therefore, in this study, the infusion methods with a higher flushing effect were investigated by performing I-HDF experiments in aqueous in vitro system.

Inulin (MW 5,000) and bovine serum albumin (MW 66,000) were dissolved in ion-exchanged water to prepare a test solution. The test solution and dialysate were pumped into a diafilter at a flow rate of 250 and 500 mL/min, respectively. The ultrafiltration rate (forward filtration) was set to 0, 15 or 30 mL/min. At every 30 minutes, the dialysate flow was stopped, and phosphate-buffered solution was infused at both inlet and outlet of the dialysate line using two extra pumps. The back filtration was induced for 40 seconds at the flow rate of 300 mL/min. The solute removal performance was evaluated by the clearance for inulin and the amount of albumin leakage.

Clearances for inulin declined over time, and no difference was observed between with and without back filtration regardless of ultrafiltration rates. Although the amount of albumin leakage increased by performing back filtration at the ultrafiltration rate of 0 and 15 mL/min, the effect of back filtration became smaller at the ultrafiltration rate of 15 mL/min, and there was little effect at 30 mL/min. Considering these results, albumin adsorbed onto the membrane, and micropores were clogged with albumin, resulting the decrease of solute remove performance. The fouling formed under relatively low ultrafiltration rate was partially removed by back filtration. However, when the membrane was fouled severely due to a large amount of ultrafiltration, back filtration was not very effective to remove the fouling and to recover the solute removal performance. In conclusion, it was found that...

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Efficient oil recovery from emulsions through PDMS decorated nanofibrous membranes via aggregation-release demulsification

Z. Yue, Y. Ding*, J. Wang, F. Liu, Chinese Academy of Sciences, China

Efficient oil/water recovery from emulsions is a challenging task for membrane separation in terms of perm-selectivity and long-term stability. Herein, this work proposes an aggregation-release demulsification mechanism to address the fouling issue and achieve efficient oil and water recovery, respectively. Specifically, an ultra-thin sub-10 nm polydimethylsiloxane (PDMS) shell layer was constructed on a hydrophilic polyacrylonitrile (PAN) nanofiber core surface through the hydrolysis and condensation between vinyltriethoxysilane (VTES) and dimethoxydimethylsilane (DMS). The aggregation-release demulsification process on the lipophilic and slippery PDMS surface could be proposed as, oil droplet adsorption, spread out, aggregation and slippery, which vacates the membrane pore space and makes way for water flow. Thus, both purified water and aggregated oil phase could be easily recovered from the permeates. The prepared membrane enabled continuous operation without cleaning. The membrane shows high water permeance (2800 L m-2 h−1 bar−1), high emulsion treatment capacity (8000 mL), and high oil (∼85 %) and water (nearly 100 %) recovery. The strategy reported in the current study might offer an opportunity for advancing practical applications of membrane separation for valuable oil products from emulsions...

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Retrievable ultrafast covalent triazine framework membranes for organic solvent nanofiltration

F. Liu, G. Li*; Ningbo Institute of Materials Technology & Engineering, China

Covalent organic frameworks (COF) membranes are considered as promising candidates for organic solvent nanofiltration (OSN) due to their well-defined porosity, high perm-selectivity, and exceptional resistance to solvents. However, irreversible membrane fouling caused by filter cake layers or pore clogging challenges the robust separation over long-term operation especially for well-known COF membranes. Here, we present novel ultrafast covalent triazine frameworks (CTF) membranes with retrievable separation performances for OSN processes. CTF-1 membrane with unitary nanopore and CTF-m membrane with binary nanopore are fabricated via an air-organic solvent interfacial polymerization technique for comparison, which demonstrates molecular-level selectivity (MWCO, ~320 Da for CTF-1 and ~625 Da for CTF-m) and ultrafast permeability for polar organic solvents. Moreover, the heterogeneous skeleton nanopores structure of CTF-m membranes facilitates efficient separation of photogenerated carriers, thus resulting in retrievable permselectivity. This work offers an efficient strategy via Donor-Acceptor structure modulation to tackle OSN membrane fouling, paving the way for applications of framework membranes...

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Cu (II)-Phenolic complex incorporated hemodialysis membranes for efficient urea removal via enhanced adsorption strategy

F. Liu*, Y. Liu; Ningbo Institute of Materials Technology & Engineering, China

The removal of urea poses a significant challenge in reclaiming waste dialysate, especially for portable dialysis. Here, we developed a novel Cu (II)-phenolic complex incorporated hemodialysis membrane through an adsorption-diffusion mechanism for efficient urea removal. The synergistic effect between the hemodialysis membrane and the adsorbent composed of tannic acid (TA), polyethyleneimine (PEI), and Fe (II)/Cu (II) bimetal ions exhibited enhanced coordination towards amine groups present in urea, resulting in rapid adsorption kinetics and high adsorption capacity via chemical interactions. Additionally, uniformly distributed Cu (II) sites on the membrane surface promoted the hemocompatibility by converting S-nitrosothiol to nitric oxide (NO), thereby inhibiting platelet activation. In simulated hemodialysis experiments, our adsorptive-diffusive membrane demonstrated high removal efficiency (~90%) for urea using 1 L dialysate compared to ~10% of pristine membrane. The incorporation of Cu (II)-phenolic complex into the hemodialysis membrane presents a novel approach for enhancing urea removal, thereby reducing dialysate consumption and simultaneously improving the hemocompatibility of the membrane...

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Activated carbon to improve the performance of membrane processes for the extraction and storage of methylene blue pollutant

M. Hlaïbi*, Saâd O., I. Mourtah, R. Ouchn, I. Mechnou, I. El Yaakouby, N. Kamil; Université HASSAN II GeMEV, Morocco

Methylene blue is a commonly used cationic dye, especially in the dyeing of cotton, wood, silk, and paper. The treatment of industrial wastewater containing similar dyes presents a major environmental concern. Different physical, chemical and biological processes have been developed and tested for the treatment of effluents loaded with these emerging pollutants. Especially techniques such as coagulation-flocculation, advanced oxidation processes, etc., which are limited and often generate polluting by-products. Activated membrane processes, simple, effective and environmentally friendly, have been adopted to respond to this challenge. In our study, we focused on the development of two polymer inclusion membranes for the treatment and recovery of methylene blue (MB). After characterization of elaborated membranes, we conducted experiments relating to the extraction and recovery processes of MB substrate, without and in the presence of activated carbon. Several parameters, permeability (P), initial flux (J0), association constant (Kass) and apparent diffusion coefficient (D*) were determined in order to quantify the membrane performances and elucidate the mechanism of studied processes. All values of activation parameters, energy (Ea), association enthalpy (ΔH#ass), dissociation enthalpy (ΔH#diss), and entropy (ΔS#), confirm ...

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Modelling of the effect of current density and contact time in electro-coagulation on membrane fouling

I.-S. Chang*, K.-R. Kim, Hoseo University, South Korea

Electro-coagulation process has been gained an attention recently because it could overcome the membrane fouling problems in MBR (membrane bio-reactor). Effect of the key operational parameters in electro-coagulation, current density (ρi) and contact time (t) on membrane fouling reduction was investigated in this study. A kinetic model for ρi and t required to reduce the membrane fouling was suggested under different MLSS concentration. Total 48 batch type experiments of electro-coagulations under different sets of current densities (2.5, 6, 12 and 24 A/m2), contact times (0, 2, 6 and 12 hr) and MLSS (mixed liquor suspended solids) concentration (4500, 6500 and 8500mg/L) were carried out respectively. After each electro-coagulation under different conditions, a series of membrane filtration was performed to get information on how much of membrane fouling was reduced. The membrane fouling decreased as the ρi and t ... but as MLSS ...

Total fouling resistances, Rt (=Rc+Rf) were calculated and compared to those of the controls (Ro), which were obtained from the experiments without electro-coagulation. A kinetic approach for the fouling reduction (Rt/Ro) rate was carried out and three equations under different MLSS concentration were suggested: ρi^n*t = constant. Those equations state that the product of ρi and t needed to reduce the fouling in certain amounts (in this study, 10% of fouling reduction) is always ...

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16:00h - Poster Viewing


F07 - Modelling and Testing of Filter Media Properties

Day: 13 November 2024
Time: 16:45 - 18:00 h
Room 2

Session Chair:
Dr. Rostand Tayong

Modeling the permeability of nonwoven fibrous media: a first step towards the development of a media design tool

E. Cabaset*, A. Charvet, N. Bardin-Monnier, D. Thomas; Lorraine University, France

The performance of non-woven fibrous media, generally used for air filtration or purification, can be evaluated via their efficiency as well as their pressure drop, which depends on their permeability at low Reynolds numbers, in accordance with Darcy's law. Real filters are generally composed of a distribution of fiber diameters, complicating the experimental determination of their characteristics.

Permeability corresponds to the square of the fiber diameter divided by a packing density function f(α). Several authors have studied equivalent diameter models to adjust this relation for fiber bimodal distributions; considering the resistance due to a distribution of fibers as the resistance of a structure composed of a single equivalent fiber diameter. Assuming all fibers have the same length, different expressions of equivalent diameter from the literature can be summarized in equation 1 ...

... These different models illustrate that no consensus has been reached in the literature. The aim of this study is therefore to establish the best approach for determining the permeability of media composed of bimodal to multimodal distributions of fibers.

To avoid various possible experimental biases, perfectly characterized structures were generated using a numerical tool, the GeoDict (2022) software. To cover a wide range of different structures, while avoiding slipping phenomena, fiber diameters ranging from 1.5 µm to 30 µm were selected, with packing density ranging from 1% to 20%. For a given fluid velocity, the pressure drop was simulated, from which the permeability of the microstructure was deduced. For each microstructure (given compacity and fiber size distribution), five simulations were carried out with a different initialization thanks to a random seed, in order to calculate an average permeability for each type of structure.

The literature models, combined with the modified Happel packing density function (Thomas et al. 2023), were compared with permeability simulations of microstructures with a bimodal fiber distribution (figure 1). The diameters d2,1 and d2,2 which exhibit significant discrepancies are not shown graphically. These results highlight that no equivalent diameter in the literature can accurately predict the permeability value of bimodal media. Thus, a new mixing law model was developed, from which a new equivalent diameter was derived (eq. 2), providing a more accurate agreement with our simulated values.

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Water permeability testing for porous materials

D. Herper*, GKD - Gebr. Kufferath AG, Germany

Permeability measurements for filter media are widely used in the industry. Especially air permeability measurements are a standard characteristic which is also included in most specification sheets of various filter media manufacturers.

Woven filter media is widely used in liquid solid separation. Despite this fact there is no standardized liquid medium permeability test focusing on filtration media which is widely used in the industry.

As water or water-based liquids are the dispersion medium in many solid-liquid separation processes, GKD has decided to build a water permeability testing bench, to be able to determine reliable values for the water permeability of a filter medium.

Although developed for woven filter materials, the test bench can be utilized to test all kins au permeable materials. The only limitation is the fact, that the test bench uses hydrostatic pressure for measurements, making it difficult to test ultra fine materials, such as membranes.

This presentation intends to show the challenges of construction, explain the measurement techniques that are used in accordance to DIN EN ISO 11058 and illustrate the possibilities that the data recorded provides for manufacturers as well as customers...

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Fast computation of the mechanical properties of filter fabrics and application to flow-induced deformaton

M. Krier*, R. Kirsch, C. Mercier, J. Orlik, S. Rief, Fraunhofer Institute for Industrial Mathematics (ITWM), Germany

In many areas of filtration application, woven filters are the preferred media type due to defined filtration properties, durability and mechanical strength. The latter feature is particularly important to counter the deformation caused by the fluid flow through the porous medium during operation.

When searching for the optimal combination of yarn material(s) and weave design (yarn strength, weave pattern) for a given application, an experimental approach using prototypes can become time-consuming and costly. In addition, empirical knowledge is of limited use when new yarn materials or material combinations are to be considered. Suitable simulation techniques can help to significantly accelerate this stage of product development and optimization.

To this end, a specialized software tool is used for both the design of the woven filter fabric and the prediction of its mechanical strength. Known quantities such as the weaving pattern, yarn diameter(s) and the yarn materials – especially their mechanical properties – serve as input data for the computation. Instead of performing 3D simulations for finding properties like tensile strength and flexural rigidity of the fabric, the simulation is sped up tremendously by using highly efficient beam models.

The simulation results are validated by comparing them to experimental data obtained by mechanical testing.

The results are applied to the coupled simulation of the deformation of the filter fabric under stationary flow on the macroscopic scale. On this length scale, a direct numerical simulation that resolves the open areas and the yarn in the grid and uses a fluid-structure interaction applied to the solid yarn would require a lot of computational resources and time. Instead, a multiscale approach as in [1] is taken: By performing CFD simulations on the microscopic length scale (i.e. the scale of the mesh holes and yarns), the flow resistance of the fabric is obtained for different strain rates. This is used for the simulation on the macroscopic scale, where the filter fabric is modelled as a (poro-)elastic shell with the effective flow resistance and mechanical properties obtained from the mesh-scale simulations. Based on the operating conditions (volumetric flow rate) a CFD simulation computes an initial pressure distribution, which represents the mechanical load on the filter fabric. This data is used for simulation of the deformation of the fabric. For the new state, another CFD simulation updates the pressure distribution. This cycle is repeated until a steady state in terms of deformation is reached.

The present paper presents the approach and the results in detail, particularly the improvements compared to previous methods...

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G11 - Mist and Droplets

Day: 13 November 2024
Time: 16:45 - 18:00 h
Room 3

On the effect of vibrations on the droplet-fiber interaction

A. Schwarzwälder*, J. Meyer, A. Dittler, Karlsruhe Institute of Technology (KIT), Germany

Coalescers are well-established for filtering tiny droplets out of mist. The commonly used filter materials are based on fibrous material and are employed in various applications and industrial environments such as oil-mist separation in oil and gas production, in aviation as part of the cabin air supply system, and in industrial air conditioners. As a result, coalescence filters are often placed near rotary machinery and in vibrating environments, where vibrations can affect their performance. The impact of vibrations on the filter performance and the underlying mechanisms of droplet-fiber interaction has not been previously investigated. In our current work, we aim to study the interaction of an already separated droplet on a single fiber acting as a collector. We use high-speed imaging technology to observe the microscopic events with state-of-the-art temporal and spatial resolution. Depending on the excitation of the fiber, the droplet can exhibit different basic forms of movement (elongation, deformation, lateral - and rotational movement). A sequence and/or a superposition of these basic forms of movement can be interpreted as mechanisms. The identified mechanisms include static, pulsating, rotating, and collapsing droplets on the fiber.

As a result of strong pulsating or rotation, a droplet can ...

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How does fibre diameter affect the efficiency and pressure drop of mechanical fibre filters loaded with liquid aerosols?

M. Dalemo*, Absolent AB, Sweden


Mechanical fibrous filters including Hepa H13 can achieve very high filtration efficiency. However, hepa filters have no drainage and the high concentration of oil mist in industrial machining processes, makes the efficiency of drainage filter cassettes upstream of the hepa filter critical to achieve long changing intervals. Fibre diameter is a critical parameter that greatly influences both efficiency and pressure drop. The effect of reducing the fibre diameter from 10 µm to 8 or 6 µm was therefore investigated in this study.


Is it preferable to use a smaller fibre diameter to increase the efficiency, even if this reduces the oil drainage capacity? Will the pressure drop increase more than the efficiency by using thinner fibres?


Experiments were carried out on four fibre cassettes loaded with oil mist (63 mg/m³). Three different glass filter materials were tested with fibre diameters of 10 µm, 8 µm and 6 µm. The three needle mat materials had different thicknesses (10, 7.5 and 5 mm) but quite similar pressure drops (118, 109 and 105 Pa). The 6 µm material was also tested in a thicker version (10 mm). Efficiency, pressure drop and oil accumulation in the cassettes were monitored until steady state was reached.

Main results

The oil trapped in the cassettes caused a continuous increase in ... After 19 to 25 days, the cassettes reached a steady state where the drainage of oil was similar to ... The pressure drop then stabilised ...

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Revolutionizing coalescing filters: Innovative methods for developing super longevity in industrial applications

Y. Y. Zhan, S.-C. Lee*, Coin Rokaki Enterprise, Taiwan

Coalescing filters play a pivotal role in filtering invisible oil mist from dirty air streams. Fibrous filters are the most commonly used method in industries such as air compressor systems, automation devices, and clean rooms. When oil mist passes through filter media, Contal et al. (2004) identified four stages during mist filtration: deposition, clogging, filming, and drainage. Kampa et al. (2014) provided a comprehensive view of liquid transportation within filters and propose a phenomenological model called “Jump and Channel Theory” to describe the filter loading process. Chang et al. (2017) demonstrated that arranging a drainage layer influences the saturation rate of each filter layer. However, previous research has focused on the filter media during the loading of oil mist, but it does not account for the changes in filters that have been pleated or assembled into cartridges. Available manufacturing method is much more crucial for the commercial market and mass production. In the market, there are two major types of manufacturing methods: pleat-type and round-type. Therefore, we not only focus on the filter cartridge during loading but also propose a schematic method to improve the performance of coalescing filters. This approach is essential for the industrial market and end users.

In this work, we introduce a new evaluation method and an improved design for coalescing filters, particularly aimed at enhancing their longevity. To compare the two manufacturing structures, we applied a novel loading system (Figure 1a) specifically for assembled filters. The concentration distribution of the challenge DEHS aerosol (Figure 1b) is applied with a loading rate of 3g/hr. Both structures utilize identical single filter media, same size of filter (Figure 2a), and adhere to a uniform 6-layer design. The only different is the inner structure. One is pleat-type filter (Figure 2b). The other is round-type filter (Figure 2c). To further compare the loading performance, the initial performance of pressure drop curve (Figure 3a) and efficiency curve (Figure 3b) are very similar under the same filtration test.

As a result of our study, the loading curves of both structures (Figure 4) demonstrates that ...

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L07 - Reliability of Lab Scale Filtration Tests

Day: 13 November 2024
Time: 16:45 - 18:00 h
Room 1

Exploring the onset of cake filtration by inline surface position laser measurement

G. Krammer*, Graz University of Technology; R. Raberger, Andritz AG, Austria

Process design of horizontal vacuum belt (HVB), drum (DF) or hyperbaric disk filters (HBF) is often based on laboratory tests and data evaluation according to VDI guideline 2762. For a suspension sample, the transient cumulative filtrate mass is recorded for filter cake formation and subsequent, often uninterrupted mechanical deliquoring via gas purge for defined operating conditions, i.e., pressure difference and temperature.

Filter cake formation starts when the first particles deposit on the filter media. Particles may adhere on the filter media as they come in contact by random (Brownian) motion or as they experience a directed force field, i.e., gravity resulting to sedimentation and by a directed flow of the liquid through the fluid-permeable filter media driven by an externally applied pressure difference – vacuum or over-pressure – and/or the hydrostatic head of the suspension itself.

By definition, filter cake formation is finished when the entire supernatant suspension has just vanished but the cake saturation is still at S=1. Moreover, subsequent liquid removal from the filter cake is immediately accompanied by a reduction of S. Traditionally, the surface of the supernatant suspension is observed optically by naked-eye through a top inspection window and, it is related to the end of cake formation.

In addition of measuring the cumulative filtrate mass by a scale, a laser distance meter is positioned above the filter cell that is capable of measuring the transient distance to the surface of the supernatant suspension through the inspection window and - once the suspension has vanished - the filter cake, respectively. The geometry of the filter cell together with the transient distance allows to calculate the transient cumulate volume and subsequently the filtrate mass passing through the filter media. While the filtrate mass experiences an accumulation in the downstream filter cell assembly resulting in a skewed recording of the filtrate mass by the scale, the laser measurement is perfectly synchronized. The laser measurement is used to also identify the end of cake formation which interferes with a distinct distance peak that is, however, not fully conclusive yet.

Three markedly different aqueous suspensions were investigated, i.e., limestone, cellulose, and talcum, respectively, that gave concordant insights: The filtrate that exits the filter cake arrives at the scale with some time delay that is almost constant. Based on the optical measurement data, the resulting...

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Influences on the filtration properties – Combination of filter resistances and initial effects

N. Benz*, F. Krull, S. Antonyuk, University of Kaiserslautern-Landau (RPTU), Germany

To layout cake filtration applications specific knowledge of the used filter media is required which interacts with the prevailing particle systems. For the reliable determination of characteristic properties such as the filter cake and the filter medium resistance, corresponding laboratory tests are necessary, which are carried out with the pressurized filter cell standardized in VDI 2762 [1].

This contribution will take a closer look at various effects relating to this measuring principle. On the one hand, it will be shown that simply adding the filter resistances when combining two or more filter media is not always correct. For this purpose, investigations are shown, which include both experimental and simulative approaches. In addition to the combination of filter resistances, initial effects at the start of the filtration measurement will also be discussed. It will be shown that the measured values of the filter media properties are generally influenced by the measuring principle used. In accordance with VDI 2762 a transparent filter cell made of polymethylmethacrylat (PMMA) was developed to better illustrate the aforementioned effects...

Alongside to the experimental proof of the initial effects, simulations were also carried out to illustrate these better. For this purpose, µCT images of the filter material used were taken (Figure 2) so that a two-dimensional CFD model could then be derived from the sectional images of the µCT scans (Figure 3). The simulation result for a flow with demineralized water at a differential pressure of 0.8 bar is shown in Figure 4, using a stationary simulation and considering turbulence and periodic boundary conditions...

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Reliable determination of cake permeability, cake compressibility and filter medium resistance from laboratory filtration tests - Why an important and challenging task?

I. Nicolaou*, NIKIFOS Ltd, Cyprus

In cake forming filtration of suspensions, we are interested in having a reliable selection, design and optimization of the selected filter equipment with minimal experimental effort. The lack of reliable and user-friendly theory-based analysis of filtration data leads to unsystematic experimental procedure in laboratory scale. This leaves no possibility to judge the experimental results and do data correction in order to get reliable filtration efficiency parameters. Furthermore, the empirical approach for the characterization of the suspensions with regard to the filtration behavior in pilot-scale tests is time consuming and uneconomical. This is due to the relatively many unsystematic tests.

The determination of the filtration parameters using a novel and theory-based laboratory experimental approach, which enables to get maximal information from minimal number of tests, will be discussed. Questions like, which experimental settings are necessary, how test results can be plotted and analyzed based on practical equations, and how correct filtration parameters can be determined even with simple apparatuses, will be answered. Emphasis will be given to the correct determination of the filtration efficiency parameters: cake permeability (pc0), cake compressibility (nc), filter medium resistance (Rm0) and filter medium compressibility (mc).

Three methods (equations) for analyzing cake forming filtration data will be presented and discussed: The integral, the “general” integral and the differential cake formation equation...

With: pc0, nc, Rm0, mc the parameters for the characterization of the filtration efficiency of a given suspension. The specific filter medium resistance hce is determined from the absolute filter medium resistance as follows: hce=pc*Rm. It will be explained, why is important to use the hce-parameter and why with practical accuracy a constant value can be used. The above three filtration test data analysis methods will be compared by demonstrating representative examples of laboratory filtration tests. important conclusions for the practical use of the above methods will be presented. It will be finally explained why the reliable determination of the above filtration parameters is a real challenge...

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M04 - Membrane Fouling

Day: 13 November 2024
Time: 16:45 - 18:00 h
Room 4

Enhancing biofouling resistance through electron beam grafting of polymer membranes with hydrogels - translating research results into practical applications

A. Schulze*, K. Fischer, J. Lohmann, I. Thomas, E. Vogelsberg, Leibniz Institute of Surface Engineering (IOM); E. Schmidt, T. H. Blaich, C. Belz, Busse GmbH, Germany

  1. Background and Aim

Fouling remains a major challenge in membrane-based filtration applications, with biofouling accounting for 45 % of total fouling. Complete prevention of biofouling or removal of the biofilm has not yet been achieved in the long term and at a reasonable cost. The modification of the membrane surface with a thin hydrogel layer combines many approaches to reduce biofouling. A hydrogel consists of an insoluble three-dimensional macromolecular network that adsorbs large amounts of water. The hydration layer acts as a barrier layer for proteins and microorganisms. In this work, a thin hydrogel layer was applied to a membrane using the environmentally friendly technique of electron beam grafting without using toxic chemicals.[1] In a first fundamental study, different hydrogels were immobilized on track-etched membranes to investigate different resulting properties (surface charge, swelling/crosslinking, surface hydrophilicity, roughness). Subsequently, the most promising hydrogel was immobilized on an ultrafiltration membrane, and the long-term performance was analyzed over a period of 11 months in a membrane bioreactor.

  1. Materials and Methods

For the fundamental study, a track etched OxyDisc® membrane (polyethylene terephthalate PET, 0.4 µm, Oxyphen, Lachen, Switzerland) was used. In the applied study, the MicroPES™ membrane (0.03 µm) from 3M (Saint Paul, MN, USA) was used. Monomer solutions were prepared in different sample compositions. The membranes were modified with an electron accelerator under a nitrogen atmosphere at different irradiation doses. Voltage and current were set to 160 kV and 10 mA, respectively. The membranes were immersed in the monomer solution for 5 minutes, placed on a glass plate and irradiated in the electron accelerator. After irradiation, the membranes were washed in water three times for 30 minutes and dried overnight at room temperature.

The membranes were characterized using water contact angle measurements, atomic force microscopy, zeta potential measurements, scanning electron microscopy and biofouling tests with algae (Chlorella vulgaris). The unmodified and modified membranes were further processed by Weise Water GmbH (Hennigsdorf, Germany) to be implemented on two sides of a carrier plate (sandwich plate design) and operated in a membrane bioreactor over a period of 11 months. The total active membrane area was 1.5 m2 per module.

  1. Results

The charge and roughness had ....

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Efficient membrane fouling mitigation in self-cleaning piezoelectric PVDF-graphene loose nanofiltration membranes for sustainable textile wastewater treatment

H.F.M. Austria*, R.P. Sardome, O. Setiwan, T.-H. Huang, J.-Y. Lai, W.-S. Hung, et al., National Taiwan University of Science and Technology, Taiwan

Despite the effectiveness and eco-friendly nature of membrane separation in wastewater treatment, the notable and unavoidable fouling problem in conventional membranes has become a substantial challenge within the field of membrane technology. Due to this factor, there is significant potential in alleviating this issue through the creation of responsive membranes capable of self-cleaning. This study introduces the fabrication of loose nanofiltration (LNF) membranes using electro-responsive poly(vinylidene fluoride) (PVDF)/graphene (PVDFGr), which exhibit self-cleaning capabilities when subjected to an external voltage. In this membrane system, varying amounts of graphene triggers the self-assembly of PVDF chains to have a dominant β-phase that is responsible for its distinctive piezoelectric characteristic. Upon subjecting the PVDF1Gr1 membrane with the best piezoelectric property to an AC voltage of 36 V during the foulant filtration test, there was no apparent change in its original permeance value for over 120 minutes unlike the control membrane that showed a continuously declining value. This proves that the membrane could effectively mitigate fouling through the inverse piezoelectric effect. By responding to an applied voltage, the membrane undergoes a deformation that causes its self-vibration, thereby expelling foulants from the membrane. Moreover, during NF testing, it was found out that this membrane has a Congo red (CR) rejection of up to 96.4%, and sodium chloride (NaCl) rejection of 1.6%. This high dye rejection and high salt transmission indicate that this piezoelectric membrane could be applied for efficient textile wastewater treatment where dyes and salts can be separated from each other, and hence sustainably recover these valuable resources.

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Use of high-precision laser nephelometry for particulate monitoring and SDI parameter

B. Verdonk*, HACH, Netherlands; D. Slovacek, HACH, USA

Whether colloidal, particulate, or microbiological, fouling represents the most significant challenge in reverse osmosis (RO) membrane management.High-precision laser nephelometry (HPLN) based on a 360-degree detection window has exhibited a significant potential solution for fouling detection for pre-R as surrogate for the silt density index (SDI)...

Laser nephelometry (LN), and in particular, high-precision laser nephelometry (HPLN) is a potential solution for detection of pre-RO fouling. Theoreticall using HPLN....

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F08 - Surface Functionalization of Filter Media

Day: 14 November 2024
Time: 09:00 - 10:15 h
Room 3

Halogen-free plasma nanocoatings to functionalize gas and liquid filter media

F. Legein*; Europlasma NV, Belgium

Plasma is a unique technology to deposit ultra-thin coatings on all exposed surfaces of a material or product. It is increasingly used in the manufacturing of filtration media and elements to achieve functionalities such as hydrophilic, hydrophobic, oleophobic, or dielectric.

Improvements in process and machine design allow the deposition of these coatings in a very cost-effective way, with a process that is completely dry and clean. The technology is giving an increasing number of producers of technical nonwovens, membranes, mesh, nanofibers or film a clear competitive edge.

The paper will start with a short introduction to plasma technology.

Then it will review industrial concepts for both batch and roll-to-roll treatment. It will also compare industrial equipment for atmospheric and low-pressure plasma deposition.

Next, an overview will be given of typical coating chemistries used for such coatings. The paper will discuss challenges in liquid-repellent coatings, more specifically the market need for halogen-free solutions. Several approaches will be presented to induce surface roughness and combine it with halogen-free plasma coatings to achieve a hydrophobic, even oleophobic effect. Case studies of these halogen-free coated materials will be presented both for gas and liquid filtration...

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Advancements in separation technology: Fabrication of sustainable eco-friendly superhydrophobic membranes

A. Zeniou*, E. Manouras, E. Gogolides, NCSR Demokritos, Greece

One of the most pressing issues facing the world today is the need for clean water. The extensive industrial use of groundwater is compromising both the quality and availability of this vital resource. Achieving near-zero liquid discharge through sustainable and effective technologies has become crucial. Membrane separation stands out as a highly promising technology, playing a pivotal role in water reuse and chemical reclamation. However, membranes are prone to fouling, scaling, and wetting, which significantly diminish their efficiency and lifespan. Recent advancements, in superhydrophobic membranes have demonstrated superior flux performance and resistance to fouling and scaling compared to traditional hydrophobic membranes. Plasma nanotextured membranes represent a significant advancement in membrane fabrication technology and other similar applications. This green and environmentally friendly surface treatment technology enhances the resistance to fouling, scaling, chemical damage, and wetting. A technology that is membrane agnostic and can transform inherently hydrophilic membranes to superhydrophobic. The surface properties achieved through plasma nanotexturing make membranes more effective in challenging conditions, such as highly acidic, high-salinity wastewater and biological waste. These advancements offer a practical solution for a wide range of applications in water purification, chemical reclamation, and desalination.

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CO2 Sorbents based on industrially activated carbons for direct air capture applications

J.-H. Boelte*, C. Einzinger, Donau Chemie AG, Austria; M. Mueller, Donau Carbon GmbH; U. Mock, P. Nolte, Corporate Research of Robert Bosch GmbH, Germany

The advancement of new adsorption techniques, such as Direct Air Capture (DAC) for removing CO2 from the atmosphere, is becoming increasingly important to achieve climate goals by reducing unavoidable and legacy CO2 emissions. During DAC, a solid sorbent is used to capture CO2 from the ambient humid air with a current level of approximately 420 parts per million.

The binding of CO2 molecules on the solid sorbents surface by adsorption can be achieved by both physisorption and chemisorption. Desorption usually happens in a closed system after the removal of excess air, applying a combination of increased temperature, reduced pressure, or steam purge. Sorbents suitable for Direct Air Capture (DAC) should possess high CO2 working capacities, demonstrate high selectivity towards CO2 adsorption, be readily available in large quantities, exhibit long-term stability, and be cost-effective [1].

In this context, activated carbons (AC) seem to hold great potential, as they have been produced for decades and are readily available on an industrial scale worldwide. As a well-known sorbent and filter material, they provide large specific surface areas, variable pore width distributions and large pore volumes. It is believed that in AC particularly micropores with estimated pore widths of 0.7 nm to 0.8 nm could be beneficial for CO2 adsorption [2].

The introduction of heteroatoms, such as N or S, into the carbon skeleton can also significantly influence the adsorption properties. [3]. As a substrate material, AC allow for further functionalization, for example by impregnation or grafting with different kinds of amines that bind CO2 by a reversible chemisorption process [4].

In this screening study, we will present a simple method to measure CO2 breakthrough curves under DAC conditions. The CO2 uptake of porous carbons was determined using a temperature-swing-adsorption approach under varying relative humidity. Additionally, special attention was given to their cyclability in several adsorption–desorption cycles.

The aim of this screening study was to investigate a series of non-functionalized, heteroatom-doped, and amine-functionalized porous carbons for their potential to adsorb CO2. The carbon adsorbents were thoroughly characterized through elemental analysis and low-temperature N2 physisorption. Additional N2 and CO2 isotherms were measured at room temperature to determine the selectivity of CO2 over N2.

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G12 - Industrial Gas Cleaning

Day: 14 November 2024
Time: 09:00 - 10:15 h
Room 2

Particle collection by wet scrubbers: in-situ study in a municipal waste incineration plant

A. Hoyos Velasquez*, A. Joubert, A. Bouhanguel, L. Le Coq, IMT Atlantique; M. Henry, S. Durécu, Séché Environnement, France

Waste incineration (WI) generates highly polluting gases requiring treatment technologies that ensure compliance with EU emission standards. With growing health and climate change concerns, limit values for particulate emissions from WI are expected to evolve to consider particle size. It is therefore crucial to ensure that fumes treatment facilities are equipped with air pollution control (APC) devices capable of capturing all particle size ranges. Simple wet scrubbers (SWS), a widely employed APC device, are not considered performant for collecting particles with a diameter of less than 1 µm. However, studies [1] have shown that by adjusting the scrubber operating conditions (e.g. droplet size, liquid to gas ratio), collection of submicron particles can be improved. Given the widespread use of these units and their potential for submicronic particle collection, it is crucial to study their behavior and optimize their performance. In this work, a downscaled wet scrubber was designed, built, and set-up in a municipal WI plant to be fed with real fumes and to study its efficiency regarding the removal of particulate matter contained in WI fumes.

The downscaled system was implemented at the municipal WI plant in Nantes (France), where domestic, medical, and industrial waste are incinerated, and which consists of a furnace, a heat recovery boiler, a cooling tower, a baghouse filter with sodium bicarbonate and lignite coke injections, and a selective catalytic NOx reduction system. The wet scrubber was installed after the cooling tower, where the fumes reach ...


The particle size distribution (PSD) at the inlet (Cin) and outlet (Cout) of the scrubber was measured to quantify its performance under operating conditions presented in Table 1. Samples were taken with isokinetic nozzles located inside the scrubber, aligned with the gas flow, and properly isolated from the spray. The inlet sample was taken at a height of 2 m, in the center of the tower and the outlet sample was taken next to the scrubber gas outlet. Particle counting was performed by using an Electrical Low Pressure Impactor (ELPI, Dekati). Short (30 – 45 s) and sequential ...

The PSD at the inlet of the downscaled wet scrubber measured by the ELPI is presented in Figure 2. This distribution can be considered as the PSD in the main industrial duct, subject to losses in the scrubber inlet line. The modal diameter is 0.31 µm for a concentration between 7 and 9 x 105 Figure 3 illustrates the collection efficiency of the downscaled wet scrubber as a function of the aerodynamic particle diameter, for the above-mentioned operating conditions. As the particle size decreases, the scrubbing efficiency also diminishes, reaching a minimum of 7% at 0.31 µm. Negative collection efficiencies (-12%) were obtained for ...

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Influence of catalyst particle properties on NOx conversion in a combined exhaust gas cleaning system using entrained flow SCR

J. Beimdiek*, S. Schiller, H.-J. Schmid, Paderborn University, Germany

The exhaust gas of combustion processes – particularly for biomass combustion – typically contains a significant number of hazardous particles and gas components. Therefore, emission legislation has become increasingly restrictive regarding these pollutants, particularly NOx. The prevailing technology for exhaust gas denitrification is selective catalytic reduction (SCR), which involves the catalytically enabled conversion of harmful NOx with ammonia to the harmless species nitrogen and water. Commonly, this is done using vanadia/titania catalysts, which are e.g. processed in filter bags or installed as standalone catalyst modules. With the former solution, the idea is to upgrade an existing filtration system to a combined gas cleaning method for removal of particulate matter and nitrogen oxides. This technique prevents an investment in a new downstream process step but requires new, more costly filter bags.

An alternative SCR technology as an attractive upgrade measure for such processes is currently being investigated and presented here. The prerequisite is that ultrafine particle separation is ensured. Many industrial filtration systems use a precoat material applied to the filter surface. Such a system efficiently precipitates even ultrafine particles and simultaneously prevents clogging of the filter material. Hence, the addition of further ultrafine particles is harmless. Therefore, the new SCR technique involves the addition of catalytically active nanoparticles synthesized in-situ in the exhaust gas stream. SCR occurs in-flight at the freshly created particle surface. Downstream, the catalyst particles are precipitated with the fly ash particles in the surface filter. Because the nanoparticles are still reactive, the filter cake serves as a fixed bed catalyst and therefore enhances the NOx separation performance. In contrast to the precoat material, the catalyst particles are not recycled. Hence, the catalyst material must be inexpensive. This represents an incentive to replace established catalysts such as vanadium oxide by e.g., iron oxide.

The integration of a particle synthesis step into the exhaust gas system has several advantages over other SCR systems. First, nanoparticles exhibit a high specific surface area. Therefore, the consumption of catalyst material is low. Second, nanoparticles have a highly reactive surface. In particular in the freshly created state, the reactivity is significantly higher. An increased reactivity enables either the use of less active metal oxides (as e.g. iron oxide) as catalyst material or the reduction of the operating temperature for SCR. Low operating temperatures are desirable and especially beneficial for combustion processes coupled with heat recovery.

The experimental results prove the

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SMF® - Hot gas filtration, potential for CO2-reduction

S. Steigert*, K. Schrewe, HJS Emission Technology GmbH & Co. KG, Germany

More than 2 million m² of HJS Sintered Metal Filter (SMF®) material have been produced within the last nearly 20 years, with a peak production of 300.000 m² p.a.. The SMF® modules are proven for a very large number of exhaust gas filtration applications for diesel engines.

Based on a comprehensive market analysis, the areas of oil / hydraulic filtration and gas dedusting were identified as the most promising market segments for SMF®. Accordingly, the filter material was qualified in accordance with the test guidelines multipass acc. ISO 16889 and VDI 3926.

The best match with the requirements of the corresponding market segment and the properties of the SMF® material was demonstrated in the area of hot gas filtration. The focus of further activities is therefore on the development and implementation of manufacturing processes that are as close as possible to series production and the further validation of such filter elements in real applications, including the optimisation of the respective regeneration parameters.

The great interest in the approach of high-temperature filtration with SMF® filter elements is mainly due to the potential CO2 savings that this offers. The effort previously required to cool the hot, dust-laden gases before filtering, which is necessary for environmental reasons, can be omitted. Furthermore, by utilising the significantly hotter, cleaner gas, energy recovery, e.g. by generating electricity, can be made much more efficient than before...

Laboratory investigation of the filtration performance according to VDI 3926 were done with different test dusts. They include two typical test dusts and one real word dust taken from a lime plant. With this results a comparison was possible to theoretical values coming from empirical formulas.

An important step for the commercialisation of this new filter technology is the capability to produce filter candles in the dimensional range today known from textile-based filter bags. For this task the final welding step on ...

Similar to the welding of the flat filter media strips to a wider raw material the final welding seam has to fulfil all the quality criteria from mechanical aspects and the possible impact of filter performance.

In customer supported projects first industrial installations of the metallic filter media were done to proof the good laboratory results in the final environment. As an example described here, a filter house was designed to fit in the existing filtration path of a lime plant...

Running the metallic filter media with different test dusts showed some significant deviation from the theoretical expected results. The real word test dust has a...

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L08 - Fundamental Studies on Sedimentation and Filtration Phenomena

Day: 14 November 2024
Time: 09:00 - 10:15 h
Room 1

Session Chair:
Prof. Bernhard Hoffner

Study on sedimentation acceleration phenomena by applying horizontal dc electric field to fine particle slurry

F. Koike*, K. Yabuki, K. Kitamura, T. Mori, Hosei University, Japan

Sedimentation separation is used in various industrial fields. In sedimentation, it is common to improve separation efficiency by adding chemicals such as flocculants to flocculate fine particles and thereby increase their sedimentation rate. However, the added chemicals remain in the separated and recovered solids(particles). Therefore, even if the recovered solids can be used for other purposes, the chemicals may prevent them from being reused as contaminant.

Therefore, we have proposed a method to accelerate sedimentation of fine particles in water by applying horizontal DC electric field without adding any chemicals. In previous studies, the mechanism of accelerated sedimentation of fine particles in water by applying horizontal DC electric field has not been fully clarified. In this study, we attempted to elucidate the mechanism by observing the accelerated sedimentation phenomenon when applying horizontal DC electric field to an aqueous slurry under various conditions, and by measuring pH and particle diameter before and after applying DC electric field.

As a result, we found that the phenomenon of accelerated particle sedimentation when applying a horizontal DC electric field to an aqueous slurry is caused by two main factors: “particle agglomeration” and “a mechanism similar to the Boycott effect, in which a particle-free region near one electrode formed by particle electrophoresis moves upward due to density flow generated by the horizontal density difference”. Furthermore ...

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Displacement meets dilution: A generalized dilution washing theory

H. Henn*, F. Sauer, B. Hoffner, Mannheim University of Applied Sciences, Germany

Displacement washing is a common process to improve product quality in a filtration process. The filter cake is permeated with a wash liquid, displacing dissolved substances from its pores. In industrial washing processes, the wash liquid is usually applied to the cake surface via spray nozzles, drip plates or overflow channels. In order to distribute the liquid homogeneously, a wash liquid supernatant is usually formed to cover the whole cake surface. The mechanical impact of the wash liquid causes the filter cake to be partially reslurried, which allows impurities from the pores to enter the supernatant and contaminate the wash liquid even before it penetrates the cake. This wash liquid contamination limits the result of displacement washing.

In recent publications by the authors, it has been shown that the extent of partial cake reslurrying can be described quantitatively using the cake reslurry ratio φ as a dimensionless and intuitive parameter. The cake reslurry ratio φ can be determined experimentally by analyzing the supernatant concentration. In this paper, a model is presented to predict the best possible washing result due to the negative effects of partial cake reslurrying based on an analysis of the contaminated supernatant. Model predictions are validated using experimentally determined wash curves. The supernatant contamination caused by partial cake reslurrying is identified as a previously undescribed limiting effect for displacement washing.

The presented model approach forms an analogy to established theories of dilution washing and can be used to describe wash limits due to partial cake reslurrying for displacement washing. This closes a gap between two of the most common washing processes and opens a new perspective for the evaluation of displacement washing results. A generalized evaluation to describe the influence of wash liquid interactions with the cake surface is enabled which provides an important approach for the optimization of washing processes. As a result, unforeseen process deviations can be identified at an early stage of process design, leading to the reduction of investment, operating and downstream processing costs.

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Influence of irregular filter cake geometry on mechanical dewatering in a gas differential pressure field

F. Sauer*, H. Henn, B. Hoffner, Mannheim University of Applied Sciences, Germany

Cake filtration and mechanical gas dewatering are well-known processes for solid-liquid separation. While cake geometry is usually assumed to be homogeneous during process design, filter cake height can certainly vary locally on industrial scale filtration equipment. E.g., unsteady and non-uniform slurry feed conditions often lead to irregular filter cake height, especially on large filter areas. In case of belt filters, these inhomogeneities can be worsened by the separation of vacuum chambers and the resulting pressure field. Even though much more extreme, a widely studied example of irregular cake geometry is cracking of filter cakes. However obvious the negative influence of irregular filter cake geometry on gas dewatering may seem, there has not yet been established a way to predict or quantify their relationship.

In this study, a two-dimensional model describing mechanical gas dewatering of isotropic filter cakes based on the law of conservation of mass and two-phase Darcian flow. A numeric scheme adopted from Kueper et al. (1991) involves grid-centered finite differences and Newton-Raphson iteration handling the non-linearity of the underlying system of PDEs. Owing to the two-dimensional approach, locally different cake heights can easily be incorporated.

By determining the overall cake saturation against time, predictions for the dewatering kinetics based on capillary pressure and relative permeability functions are possible. Simulated saturation fields give an insight into the transient distribution of pore liquid during dewatering. The volume flow of gas produced can be calculated as well.

As a result, inhomogeneous cake height can affect gas dewatering negatively. Compared to homogeneous filter cakes, both the saturation decrease and the gas volume flow at a constant gas differential pressure are influenced. This can be explained by nonuniform flow leading to different residence time distributions of gas within the filter cake.

Experimental data of filter cakes with exemplary cake geometries is used for validating the model. Comparison of gas velocity and liquid saturation between experiment and model prediction looks promising. Going forward, this work helps to describe the impact of irregular cake geometries occurring in industrial processes.

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M05 - Cross Flow Techniques

Day: 14 November 2024
Time: 09:00 - 10:15 h
Room 4

Next level optimization of your dynamic crossflow filter (DCF) performance with digital twins

M. Stahl*, J. Rauhut; Andritz Separation GmbH, Germany

Cross-flow technology for separating substances with poor filtration properties are state of the art technology for solid-liquid separation in chemical and pharmaceutical industry. With traditional cross-flow filtration the development of the clogging layer at the surface of the filter membranes is prevented by re-circulating the feed. When handling sensitive or highly viscous products, this method is not efficient or even not applicable. With Andritz Dynamic Cross Flow filtration (DCF) recirculation can be avoided and processing of high viscous products with pasty consistency is possible.

In DCF shear forces are generated between the overlapping rotating disks. By this effect, the crossflow is generated without pumping and circulating the slurry, but just by the rotation of the membranes themselves...

For most of the players in food and chemical industries, using a DCF is an efficient way to filtrate different products but today, operations need significant improvement to gain in productivity and reduce opex. Up to now, the huge potential of Dynamic Crossflow Filter technology in industrial processes is often not utilized, because quick reaction time of the system to varying process conditions are not possible by fixed recipes. In order to further increase long-term performance of DCF and allow the handling of varying process conditions a digital twin was developed for an industrial DCF plant. The digital replica of the physical process uses asset-specific information such as actual physical dimensions and equipment characteristics and runs in parallel with operations, continuously calculating key process parameters which sometimes cannot be measured or are difficult to measure by traditional instrumentation. Through proven simulation capabilities, combined with live plant data as an input, it calculates continuously the optimal flow setpoint, and performs what-if scenario analysis.

During the harvesting season in 2022 and 2023 in total 24 industrial production batches of grape juice were analyzed in this project. After implementation of the digital twin the...

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Bone/muscle-inspired polymer porous matrix toughened carbon nanofibrous catalytic membranes for robust emerging contaminants removal

N. Lu, F. Liu*, Ningbo Institute of Materials Technology & Engineering, China

Catalytic membranes are able to conquer the hurdles of common heterogeneous catalysts via facilitated convection/diffusion-reaction process, which efficiently eliminate emerging contaminants (ECs) without secondary contamination. It is challenging to maintain steady advanced oxidation efficiency via rationally designing the robust nano-architectures of catalytic membranes. Inspired by tenacious bone/muscle structure, we for the first time synthesized polyvinylidene fluoride shells and micro-webs intensified carbon catalytic nanofibrous membranes (PVDF-CCNM) using a flash freezing route, achieving instantaneous ECs degradation (e.g. 98.9 ± 0.5% of tetracycline) and producing a massive water throughput (e.g. 29.4 × 103 L m−2) in 84 h under continuous cross-flow filtration, superior to state-of-the-art catalytic membranes. The resulted membrane showed a much higher apparent reaction constant value (1353.5 μmol g−1 min−1) during the dynamic filtration system than that (4.9 μmol g−1 min−1) in batch system, ascribing to forced convection and facilitated diffusion-reaction. Moreover, the resulted membrane exhibited strong resistance to various anions and broad pH range due to the 1O2 dominated catalytic degradation mechanism, which allows for remediating actual high-salinity coal chemical wastewater. This work highlights an innovative catalytic membrane design for robust and practical treatment of recalcitrant pollutants...

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Buoyancy-enhanced membrane filtration for oilfield and industrial water reuse

P. Christou*, Swirltex Inc., Canada

Membrane-based water treatment has been widely used in various industries for effective wastewater filtration. However, conventional membrane processes suffer from drawbacks such as high energy consumption, fouling, and maintenance costs, making them expensive to operate. This restricts their application in industrial wastewater and oilfield produced waters, which often contain solids and oil.

To address these challenges, a proprietary process known as buoyancy-enhanced membrane filtration (BEMF) has been developed. BEMF significantly reduces energy consumption, fouling, and maintenance requirements compared to conventional polymeric tubular membranes, making it suitable for challenging wastewater applications. Additionally, the BEMF process allows conventional membranes to operate at 3x–6x higher flux rates, leading to reduced equipment size requirements.

The BEMF process achieves its benefits through a two-step hydraulic manipulation of wastewater. First, air injection facilitates bubble attachment to oils, solids, and other contaminants. Second, a spiral flow pattern induces buoyancy-based separation of water and contaminants. This leads to the formation of an annular flow along the membrane length, with contaminants and gas concentrated at the center of the membrane tubes.

The effectiveness of BEMF has been demonstrated in various industrial applications. For instance, in the mining industry, BEMF successfully filters highly contaminated coal wastewater with low energy and fouling. Railyard wastewater, rich in solids, oil, and grease, also benefits from BEMF filtration, achieving high removal efficiency. Moreover, the BEMF process also serves as an efficient pre-treatment step for lithium recovery from brine water and wastewater, reducing the need for environmentally intrusive and slow evaporation/precipitation processes.

Oil and gas companies have embraced the BEMF process to recycle and reuse oilfield produced water, minimizing freshwater usage and transportation. A 20,000 barrels per day (BWPD) BEMF system deployed in Canada is the country’s largest produced water ultrafiltration system. Data from this system's operation and filtration will be presented as a technical case study...

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10:15h - Coffee Break


F09 - Enhancement of Filter Media Performance

Day: 14 November 2024
Time: 10:45 - 12:00 h
Room 3

Combining mechanical robustness, small pore sizes and high permeabilities in one filter medium

M. Müller*, Spörl KG, Germany

At the last Filtech-conference in 2023 the newly developed Betamesh-PLUS as woven wire meshes for energy-efficient filtration processes were presented. Using a woven wire cloth of this weaving type as filter medium, a filtration process with highest separation efficiencies at lowest power consumptions can be realized. With the Betamesh-PLUS, geometric pore sizes down to 5µm can be realized.

Until now, Dutch Twilled Weaves with their low porosity, low free passage area, low dirt-holding capacity and poor cleaning behavior had to be used for this small pore sizes. In the Betamesh-PLUS the wire diameters of the warp and weft as well as the pitches are combined in such a way, that these fabrics are characterized by a high permeability, a high dirt-holding capacity and ideal back flushing properties.

Due to the realized slit-shaped pores and larger number of pores of the Betamesh-PLUS compared to the Dutch Twilled Weaves, they are characterized by a significantly lower increase of the pressure loss with increasing filter loading and thus a longer service life of the filter medium. Also, the removal of deposited particles from the filter medium e. g. by a pulse-jet is much easier compared to the Dutch Twilled Weaves, since the smallest pore is located on the top of the woven wire mesh. A low remaining pressure loss and consequently a low power consumption result.

The finer the mesh, the thinner the used wires must be chosen. However, this also reduces the mechanical stability of the wire mesh. Betamesh-PLUS with its small pore sizes can also be used as a filter layer in so-called composite-cloths so that these fine meshes can also be used under harsh operating conditions. In composite-cloths, the filter layer is bonded to one or more coarser supporting, protection and drainage layers over the entire surface in a high-temperature sintering process.

These further layers are woven wire meshes with a large aperture size made out of relatively thick wires. Using these mechanical very stable coarse supporting layers with their high permeability in the composite-cloths, the ... The other advantageous filtration properties such as the high dirt-holding capacity and the good back-cleaning behavior are also given in the composite-cloths.

Within the paper, the filtration performance of these composite-cloths is analyzed on the basis of the initial pressure loss, the absolute pore size, the dirt-holding capacity, the load-depending separation efficiency and the cleaning behavior. These quantifying parameters are determined experimentally using a flow rate test-rig, an air-solid test-rig and a cleaning test-rig based on DIN ISO 11057 and are compared with the performance of the single-layered Betamesh-PLUS.

The influence of one or two supporting layers in the composite-cloth on the ... To protect the filter layer, a coarse wire cloth, a so-called protection layer, can be sintered as first layer of the composite-cloth onto it. The paper shows how the permeability and dirt-holding capacity, and therefore the service life of the filter medium, is massively reduced using ... Between the protection layer and the filtration layer, a trapped grain can occur, which can no longer be removed during back-cleaning. Back-cleaning tests using pulse-jet cleaning illustrate how these not-removable particles increase the residual pressure loss.

If cylindrical filter elements are subjected to external pressure, the maximum possible pressure until the element buckles depends not only on the geometry but also on the mechanical properties of the filter material used. For the experimental investigation of this maximal pressure, the so-called buckling pressure, a special test-rig was set up, with which it is possible to pressurize filter cylinders of different geometries. In addition to the geometry, the layer structure of the composite-cloth was also varied during the tests. Based on the results ...

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Proline - New gradient filter media for enhanced filtration performance

H. Yu*, S. Jaganathan, S. Jinka, M. Silin, M. L. Turner, J. Alarcon, et al., Hollingsworth & Vose, USA

Typically, to achieve higher dirt holding capacity (DHC) for a given efficiency, a filter media is designed to be dual phase with a gradient density in Z direction. Hollingsworth and Vose’s (H&V) newest development called ProLine(R) Filter media not only provides gradience in density but also provides gradience in fiber orientation. This makes it the best filter media in the market for a number of applications spanning both air and liquid filtration.

This new patented platform of media has significant improvement in DHC (up to 100%) and air permeability (up to 40%) for a given efficiency. Substantial rearrangement of fibers generates higher surface area and new channels for air and liquid contamination capture. As a result, filter elements produced with these media can offer a significant improvement in service life, reduced pressure drop or a combination thereof. ProLine allows to modify media basis weight and get similar performance, which could be translated into less media consumption into the filter. Initial development of these novel media is focused on applications in hydraulic, fuel and engine air filtration.

This paper present the media’s surface morphology is characterized by using 3D surface analyzer and X-ray Micro CT Tomography. Quantitative characterization of media disruption caused by Proline(R) treatment involved assessing variations in out-of-plane orientation, specifically the orientation of fibers relative to the thickness axis of the web, across the media thickness.

In addition, a model was developed, quantifying the total cost of ownership (TCO) and optimal filter replacement time for the hydraulic filtration system. The TCO includes costs of the filter element, its installation and disposal and the costs of the energy needed to operate the pump. The model combines the results of the element characterization via the ISO16899 Multi-Pass test with realistic assumptions on the hydraulic system operating conditions. Presented TCO comparisons quantify the value proposition of the elements with the ProLine media for the end-user.

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Efficient workflow for optimal pressure drop of pleated filters

P. Eichheimer*, L. Cheng, A. Wiegmann, Math2Market GmbH, Germany

In recent years, the demands of the industry to enhance filtration performance increased the use of digital tools to design new filter element shapes. Computer-Aided Design (CAD) is crucial, not just for detailed designs but also for broader simulations analyzing flow and filtration within filters.

However, conducting systematic simulations across different designs requires creating and importing CAD data into the CAE engine one by one, which can be time-consuming. To tackle this, we present a digital workflow to generate cylindrical pleat structures with variations in pleat count, thickness, and the number of porous layers in our own CAE engine, GeoDict. The creation and assessment of pleat structures is simplified, enabling a streamlined evaluation of the impact of their characteristics on key filtration parameters.

In addition to that, computational resources and simulation time of filter flow performance are reduced significantly with a multi-scale approach. Instead of simulating each fiber individually, porous layers are used, incorporating effective parameters as input parameter. These input parameters are derived from microscale simulations or flat sheet experiments.

In the presented study different filter structures are simulated to identify the most efficient configuration to minimize pressure drop while maximizing filter area. Since only the most promising prototypes undergo further physical evaluation, the result is a great reduction of ... Moreover, cloud platforms enable simultaneous simulations of various designs and differing flow rates, enhancing overall productivity.

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G13 - Modelling and Simulation I

Day: 14 November 2024
Time: 10:45 - 12:00 h
Room 2

Improved finite differences flow solver for 3D microscale filtration simulations with dnslab®

K. Schmidt*, V. Puderbach, A. Ataei; IT for Engineering (it4e) GmbH, Germany

DNSlab is a software for analysis and simulation of mass transport and deposition especially in microporous filter media. The computation of gas or liquid flow fields in 3D models of the media is used for the determination of the permeability, the filter efficiency and filter cake build-up and backwashing, amongst others.

DNSlab provides Finite Differences (FD) and Lattice-Boltzmann (LB) schemes to compute flow fields. The FD schemes are advantageous for slow creeping flows, the LB schemes for faster inertial flows. DNSlab’s FD schemes feature low memory consumption and ultimate numerical stability for creeping flows, as they always converge for any 3D geometry.

The contribution shows the recent FD scheme improvements in DNSlab, which enable the users to run simulations faster with larger, more representative 3D models, and less computing resources. A typical nonwoven model is used to compare the performance of the different FD scheme versions. The simulations are run on a practicable low-cost gaming PC.

The 2024 version has the lowest computing time, the lowest memory requirement and gives the most precise result on the non-coarsened voxel grid, meaning that it performs...

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Modeling the entire filtration process from depth filtration to surface filtration with a multi-layer construction and offset for dust cake growth

Q. Zhang, University of Wuppertal, Germany

A new, clean filter medium for dust separation always begins with an initial phase in which dust separation can be described according to the principle of depth filtration in the given medium. If dust separation is carried out on the given filter medium for a sufficiently long time, a dust cake can form after a completed clogging phase. This is often a gradual process. For typical depth filter applications, the longest possible clogging phase with a moderate increase in pressure loss is advantageous. In contrast, when using surface filters, the cake-forming filtration after the shortest possible clogging phase is desirable. While the filtration kinetics of a depth filter can be investigated using various model approaches (dendrite growth model or fiber growth model) to describe particle separation in the clogging phase, the transition to surface filtration by continuing the same model calculation is not yet possible, as the dust cake growth, which simultaneously means the expansion of the initial packing, is not achieved by the underlying separation theory, but by a separate add-on model. So far, there is no coherent model for a holistic view of the entire filtration process.

In this paper, a multi-layer model with offset for dust cake growth is presented, which enables the description of particle separation during the entire filtration process without a separate add-on model for switching between depth and surface filtration. The results of the model calculations are compared ...

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Dust holding capacity and filtration efficiency prediction in a 2W air filter assembly using CFD

S.D. Kukian*, G.G. Garkhedkar, S.M. Chakote, Varroc Polymers Ltd., India

In the present world of constant redevelopment and construction, the amount of dust freely floating in the air near major streets and roads are extremely high and inconsistent which can lead to filtration products not performing as per requirement.

The study aims to develop a CFD methodology to simulate the Dust Holding Capacity (DHC), Filtration Efficiency and understand Dust particle behaviour when it flows through a 2W Air intake Assembly. The Dust that is present in the air is of various compositions, sizes, shapes etc and these properties of the dust effect the behaviour when it floats through the air. A primary performance evaluation factor for Air Filter assembly is the Dust holding capacity, which also decides the service interval for the filter element along with filtration efficiency.

Our goal for this study is to develop a CFD methodology by which both DHC and efficiency can be evaluated for a Filter Assembly and results are going to be verified using Test Bench data. Filtration of particles based on particle size will also be used to accurately predict how much of the dust particle will be captured by the filtration media. From this study we hope to prepare a robust methodology to setup air filter assemblies using CFD to predict DHC and Filtration efficiency which will help us develop better and more efficient products resulting in lower vehicle emissions and reduced wear and tear of critical engine internal components..

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L09 - Modelling of Compressible Particle Layers

Day: 14 November 2024
Time: 10:45 - 12:00 h
Room 1

Modeling of cake compression behavior – Comparison of approaches

T. Buchwald*, U. A. Peuker, Technical University Bergakademie Freiberg, Germany

The formation of compressible filter cakes under constant pressure has been the subject of many studies, as it is important for the determination of filtration resistances for use in scale-up calculations. Often, the model equations of Tiller et al. are used that describe the relationship between cake resistance, compressive stress, and porosity as a power law model.

In this talk, we argue that the Tiller equations may not be the most appropriate ones for the description of cake filtration experiments. First, a curious case of filtration experiments is shown in which filter cakes expand at higher pressures in the common constant-pressure laboratory setup.

Secondly, several approaches for the description of compressible cake behavior are described, resulting in a set of possible simulation models for the filtrate flow curve over time. One of these approaches is that of Tiller, with two more models describing the decrease of pressure drop in newly formed cake layers over time and the decrease in filtrate flow as physical reasons for the compression of cake layers over time.

Finally, simulation results are shown, which were fit to experimental filtrate flow curves. It is explained that several different physical processes can lead to an uneven build-up of porosity over the length of the filter cake...

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Experimental and numerical analysis of compressible sediment layer during centrifugation of elastic-plastic microparticles

A. Lier*, F. Krull, S. Antonyuk, University of Kaiserslautern-Landau (RPTU), Germany

Filter centrifuges are used in many industrial processes for solid-liquid separation. They can enable the filtration of small and valuable samples [1]. The compression of a filter cake can change the porosity distribution and thus increase the flow resistance, which means that a higher pressure difference is required for solid-liquid separation.

In this work the compression behaviour of particle layers, consisting of elastic-plastic microparticles, has been investigated depending on the centrifugal force using experiments and coupled CFD-DEM simulations. In an analytical photocentrifuge (LUMiSizer, LUM GmbH), suspensions of ethanol and spherical paraffin particles (100 - 250 µm) were centrifuged at different rotational speeds up to 4000 rpm and temperatures (20 - 40°C) in order to investigate the plastic deformation of the particles depending on their mechanical properties and acting centrifugal force.

By a spatially and time-resolved extinction measurement in the LUMiSizer, the change of the sediment height with increasing rotational speed was measured. The compressed sediment layers from the experiments were analysed using μCT imaging (TomoScope L, Werth Messtechnik GmbH) to determine the porosity distribution in the sediment ...

To understand the mechanics of the compression and the particle motion in a centrifuge, coupled CFD-DEM simulations were performed with a

The simulations and the experiments showed that a stronger compression of the ... is achieved with increasing speed of rotation and therefore centrifugal force. The compression occurs due to plastic deformation of the particles, which is dependent on the yield pressure. The porosity of the sediment also decreases more strongly towards ...

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Influence of the cake compressibility on the performance of filter centrifuges

I. Nicolaou*, NIKIFOS Ltd., Cyprus

The reliable and optimal operation of Filter Centrifuges is in many cases a challenge. The reliable prediction of the centrifuge performance based on praxis oriented (half empirical) equations for the cake formation, cake washing and cake deliquoring step with minimal number of systematic tests is a great help for the proper centrifuge design, the optimal operation but also for the performance judgment and troubleshooting for filter centrifuges already in operation. Such mathematical models are the basis of the CENTRISTAR software. This novel program enables among others the simulation of the performance of Batch Filter centrifuges as well as the analysis of laboratory and pilot test data. Guided by the theory, the systematic experiments are reduced to a minimum, because only those tests are needed, which are necessary for the determination of the equations adaptation parameters (the so-called efficiency parameters).

The most important efficiency parameter is the cake permeability pc (or the cake resistance rc with rc=1/pc) because this parameter influences not only the cake formation step but also the optional steps of cake washing and cake deliquoring. The higher the pc-value, the higher he centrifuge performance. The cake permeability pc is not a constant parameter but depends on the centrifugal pressure (Dpc) and the cake compressibility (nc):..

In this paper, the influence of the cake compressibility on cake formation, cake washing and cake deliquoring in filter centrifuges will be presented. The cake compressibility nc can have values from 0 to 1. A value of nc=0 means a not compressible cake and nc=1 means maximal cake compressibility. The prediction of the centrifuge performance for different rotational speeds (that means for different centrifugal pressures Dpc) requires the calculation of the cake permeability pc and this requires reliable values for the cake compressibility (see above equation). Besides the influence of the cake compressibility on the dry solids mass rate (qms), the cake moisture content (Rf) and the cycle time (tc), the method for the determination of the cake compressibility via analysis of tests will be discussed. For a given application, by not considering the cake compressibility or by using wrong compressibility values means that any performance prediction for different rotational speeds will be not reliable. In fig. 1 a screenshot of the Tables & Charts module of the CENTRISTAR software shows for a given application how the cake compressibility can influence the cake moisture content, the specific dry solids rate and the cycle time. The higher the ...

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M06 - Microfiltration

Day: 14 November 2024
Time: 10:45 - 12:00 h
Room 4

Mechanism of shear-enhanced microfiltration for bio-suspension separation

S.-E. Wu*, K.-Y. Lin, Chung Yuan, Christian University; T.-L. Wei, Tamkang University, Taiwan

The separation performance is determined by the purification efficiency and the operation rate when membrane filtration is used for bio-separation. The Rotating-disk dynamic filter was designed and built in this case. Several hydrodynamic operating conditions, including rotation effect and feed flow rate, were used for reducing membrane fouling, increasing the permeating flux and improving the protein production. Furthermore, the distributions of fluid velocity and shear stress were simulated by using computational fluid dynamics. In shear-enhanced filtration system, the membrane fouling was mainly attributed to PMMA particle deposition on the membrane surface and in the membrane pores, respectively. Combined with shear-enhanced filtration experimental data concerning cake properties, such as thickness, porosity, and specific filtration resistance, the mechanism of cake formation based on a force balance model was analyzed. The effects of these operations on the filtration resistances, filtration fluxes and protein rejection were thoroughly discussed.

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Wastewater recovery & reuse - A zero liquid discharge case study

P. Cartwright*, Cartwright Consulting Co., USA

Wastewater Recovery & Reuse - A Zero Liquid Discharge Study

There is a strong incentive in the state of California for commercial and industrial facilities to practice zero liquid discharge (ZLD) in the design and operation of water purification systems. This means that only solids leave the treatment system.

This presentation addresses the challenges presented in treating the wastewater from an EDR (electrodialysis reversal) treatment system utilized by a large recreational facility. The EDR system was installed to treat wellwater for all the water requirements in the facility.

The EDR treated effluent meets the quality requirements of the Safe Drinking Water Act, but generates approximately 60,000 gpd of wastewater particularly high in calcium, magnesium and silica compounds. After pilot testing, a treatment system was designed as follows: ...

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A scientific approach for characterization of fouling mechanism in micellar casein concentrate production using ceramic microfiltration : Thermodynamic and kinetic concepts

S. Naghizadeh Raeisi*, A. Alghooneh, S.J. Razavi Zahedkolaei, Kalleh Dairy Company, Iran

Modelling is necceary for designing of a new process and developing a better insight of the present process. Appropriate model could reduce the computation time and the amount of practical work required prior to designing a new membrane process. The present theoretical approaches to predict the microfiltration performance of colloidal solutions are based on models such as mass transfer model (film theory), gel-polarization model, osmotic pressure model, boundary layer-adsorption model, Brownian diffusion model, shear-induced diffusion model, inertial lift model and surface transport model. Each of them has a number of limitations such as: (i) they need some experimental data to estimate some model parameters, (ii) none of them can describe the full flux–time pattern of process with non-linear nature, (iii) they are mathematically complex, (iii) they need a good knowledge of the physicochemical properties of fluent. In this way, there is not a completely theoretical model that accomplishes to quantitatively describe microfiltration process dynamics very accurately, which led to many design procedures being empirical and system specific. In view of the importance of microfiltration in the dairy industry, in this study, the authors investigated the a scientific approach for characterization of fouling mechanism based on thermodynamic and kinetic concepts.

Aim: Herein, the effect of temperature (5, 20, 35 & 50°c) and pH (5.5, 6, 6.5 &7) were comprehensively investigated on flux decline kinetic pattern, fouling mechanism, mass transfer and thermodynamic of serum protein permeation across the microfiltration process of micellar casein concentrate (MCC) production.

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12:00 h - Lunch


F10 - Electro- and Melt-Spun Filter Media

Day: 14 November 2024
Time: 13:00 - 14:15 h
Room 3

Design and development of 3D structured electro-spun filter media for personalised nose mask to tackle gaseous pollutant in the polluted air

M. Basak*, S. Bakshib, S. Mukherjee, National Institute of Fashion Technology (NIFT) Kolkata, India

Air pollution has become perennial problem to human health as well as poses a significant environmental risk to the Mother Earth we live in[i]. Various matters like atmospheric dust, various harmful gasses and particulate matters, air-borne viruses, bacteria, microorganisms etc., in the air make contributes hugely to the major causes of global burden of diseases causing various respiratory health issues and increased sources of morbidity and mortality to human life.

Mask gives protection to human health from polluted air, be it in the form of particulate matter or gases[ii]. Post-Covid, the production of personal masks has increased significantly because of increased personal use of disposable face mask[iii]. This brings its own problems of sustainability issues in the environment. The authors designed an aesthetically appealing nose mask by 3D scanning of the users’ face that would not only help people to filter out majority of the inhaled air but also offer sustainable solutions to meet few goals of the SDGs by UN, thereby reducing the impact of the polluted air on human health.

This current research aims to efficiently tackle such challenges and demonstrates environmentally and financially sustainable design solution by designing a 3D filter media and functionalised the filter media with specific chemical agents that would target filtration of gaseous pollutant in the air.

[i] Cohen, A.J.; Brauer, M.; Burnett, R.; Anderson, H.R.; Frostad, J.; Estep, K.; Balakrishnan, K.; Brunekreef, B.; Dandona, L.; Dandona, R.; et al. Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution: An analysis of data from the Global Burden of Diseases Study 2015. Lancet, 389, 2017, pp.1907–1918.

[ii] Anthony Bissiri, Junfeng Jiao & Yefu Chen, A scoping review of the benefits of face mask use on pedestrian and bicyclist exposure to air pollutant, Journal of Transport & Health, Vol 26, 2022, 101484

[iii] S. Steve Zhou, Salimatu Lukula, Cory Chiossone, Raymond W. Nims, Donna B. Suchmann, & M. Khalid Ijaz, Journal of Thoracic Disease, Vol 10 (3), 2018, pp.2059-2069

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Production of filter media using recycled polyethylene terephthalate (PET) and polystyrene (PS) by electrospinning technique: Evaluation of air nanoparticle filtration and permeability

F.A. Lima*, A.C.C. Vieira, M.L. Aguiar, V.G. Guerra, Federal University of São Carlos, Brazil

The development of plastic materials was crucial for improving the quality of life and helped in the growth of various sectors of society. However, humans have shown themselves to be major producers of waste on a global scale, increasing the amount of plastic waste produced each year. Among the most important and commonly used plastics are PET and PS, which represent a worldwide problem due to the high generation of waste. Due to its improper disposal and major pollution problem, an efficient technique to recycle this waste is interesting. One of the ways to do this is to use nanotechnological processes to produce a differentiated material with high added value. Among the methods, electrospinning is a promising method for the production of filter media for air treatment. This technique allows to obtain fibers in a nanoscale in a simple way and with different morphologies.

The present work aims at the development of nano and micrometric fibers with high efficiency, low-pressure drops, and high resistance using PET and PS waste. A methodology was used to develop a triple-layer filter medium (PET/PS/PET) obtained by different PET electrospinning times (0.0, 5.0, and 10.0 min) and keeping the PS electrospinning time fixed (5.0 min), verifying the impact of this on nanoparticle collection efficiency, air permeability and mechanical strength of filter media. For the electrospinning process, an applied voltage of 25 kV, a distance between the collector and needle of 10 cm, and an injection flow rate of the polymeric solution of 0.8 mL/h was used.

It was observed that the polystyrene fibers tended to be more intertwined in one layer of PET, while the other did not show great adhesion between the fibers. It was possible to greatly increase the mechanical strength with the addition of PET layers, with an increase in modulus of elasticity, maximum stress, and maximum strain at break of 4.2, 12.5, and 14 times, respectively. The efficiencies of...

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Increasing the yield in melt spinning of recycled polymer

S. Vandendijk*, Bekaert NV, Belgium; L. Beek, RWTH Aachen University, Germany

The recycling of textiles from all sectors, whether clothing, home textiles or technical textiles, is an essential part of enabling a holistic circular economy. PET is the most widely used material for all textiles worldwide, which makes the recycling of this polymer particularly relevant. However, if the recycled PET pellets are to be spun back into filament yarn, various challenges arise. These are the low quality of the filament, the processability of the filament in further process steps and the reduction in the operating time of the melt spinning plant. All three difficulties can be significantly influenced by one component of the melt spinning system: The polymer filter in the spin pack. The filter properties can be optimized by optimizing the diameter of the metal fibres used in the filter, the fibre placement and the filter structure. For this purpose, the metal fibers are sintered, resulting in up to 20 connection points per fiber. This leads to a mechanically stable and twisted pore structure. The novel filter shows a 10x higher dirt holding capacity at the same pressure drop in comparison to conventional filter media while maintaining a stable pressure inside the spinning package. Such filters were successfully developed at Bekaert and tested at the ITA from RWTH Aachen University...

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G14 - Modelling and Simulation II

Day: 14 November 2024
Time: 13:00 - 14:15 h
Room 2

Influence of material compression on the mechanical and electrostatic capturing efficiency of filter media

C. Mercier*, R. Kirsch, S. Osterroth, Fraunhofer Institute for Industrial Mathematics (ITWM); S. Antonyuk, University of Kaiserslautern (TUK), Germany

It is well known that filter media are exposed to compression during the manufacturing process. The transportation via conveyor belt rolls compacts the medium over the entire surface, changing the filter performance, i.e. efficiency, pressure drop and dust holding capacity. Further processing steps such as pleating compress the filter media locally at the tops and bottoms. The nonuniform permeability leads to a reorientation of the flow field so that the filter surface is not utilized optimally. Experimental measurement series are very helpful for the design and optimization of the manufacturing process and the nonwoven fabric. Nonetheless, they are associated with large efforts in time and cost.

This work provides an overview of the influence of compression on the filter performance of flat filter media. The pressure drop across the media as well as the fractional efficiency are predicted by models. The approach is based solely on measured material characteristics of the uncompressed nonwoven and requires no additional experimental effort for the compressed material (see Figure 1).

The data basis for the analysis of pressure drop is provided by five nonwovens, which differ by their fields of application and media structure to ensure a broad validity of the presented model. SEM images as well as measurements of the thickness, the area weight and the correlation between pressure and velocity characterize the uncompressed media. The prediction of the pressure drop for multiple compression levels is based on the Darcy-Forchheimer law [1] whereby relevant model parameters (permeability, inertial loss coefficient) are scaled with suitable models [2] referring to the change of material thickness and the corresponding reduction of porosity.

Based on one of the five filter media, which is an electret filter, the experiments are extended to include the fractional efficiency. Single fiber efficiency (SFE) models [3] are a reasonable choice for modeling porous media that consist of fibers. The mechanisms of diffusion, direct interception, inertial impaction, electrophoresis and dielectrophoresis are distinguished. Numerous models are available in the literature (see e.g. [4]), although the accuracy of the models can vary depending on the filter medium or moreover the manufacturing process. A suitable combination of these models paired with weighting factors describes the initial efficiency and can be extended by considering only the changes of material thickness and porosity.

The proposed methods allow for ...

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Modeling of charge distributions, dielectrophoresis and charge decay in electret filter media

L. Cheng*, A. Weber, P. Eichheimer, J. Becker, D. Michel, A. Wiegmann, Math2Market GmbH; S. Schumacher, T. van der Zwaag, T. Engelke, Institute of Energy and Environmental Technology e.V. (IUTA), Germany

Electret filters find widespread application across various industries due to their exceptional filtration efficiency. These filters operate on the principle of electrostatic attraction between charged fibers and particles, electrophoresis and dielectrophoresis. However, research on electret filter media faces numerous challenges and complexities, such as charge stability over time, charge uniformity, and distribution of charges, particularly on the fibers.

In this context, numerical simulations play a crucial role in deepening the understanding of the fundamental mechanisms governing the behavior of electret filter media. They provide valuable insights into the complex interplay among electrostatic forces, airflow dynamics, and particle behavior, aspects not easily observable or measurable through experiments.

For the simulations of particulate filtration in filter media and elements, the FilterDict module of GeoDict stands out as a powerful software tool. Its capabilities to perform direct numerical simulations of electrophoresis are currently being enhanced in the framework of the ElekSim project, funded by the German Federal Ministry for Economic Affairs and Climate Action (BMWK). The overall objective of this project is to develop a new simulation environment focusing specifically on electret filters with the aim to streamline the optimization of electret filter media and to validate it against measurements. So far we have the comparison of simulation results of real filter media originating from different charging processes such as hydro charging, corona charging and triboelectric charging. The FilterDict developments include simulating diverse charge distributions in both particles and fibers, adding dielectrophoresis to existing electrophoresis capabilities, and tracking surface charge decay in electret filter media over time.

The initial verification of this simulation methodology is compared against results from Fluent® on a single fiber and simple multi-fiber models and includes a comparison of the computed filter efficiency across a given particle size distribution. Next, the new features will be validated against measurements on provided µCT scans. To investigate the effects of electrostatic charge on the filter efficiency, the filter media are additionally discharged using isopropanol to expose the pure mechanical filtration characteristics.

These insights will allow drawing new conclusions for the design of innovative next-generation electret filter media with different charge distribution methods, structural configurations, and improved charge stability.

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CDF simulation for investigating the performance of filter separator in the inlet of city gate station under real operation conditions

M. Rasooly, Isfahan University; F. Hosseini, Islamic Azad University; Iran

Natural gas is one of the important sources of energy and, due to the huge reserves of natural gas, it is transferred using a network of pipelines and through the urban network, it is available to industrial, commercial and domestic consumers. In natural gas tanks, a significant amount of it is available, but along with that, there are also amounts of condensate, moisture, and solid particles, which can cause pressure drops and damage the transmission lines and facilities [1]. Using a suitable filtration system with optimal performance while preventing gas flow pressure drop in the gas supply network, prevents damage to the equipment of gas stations. The best economical solution to deal with problems and save operating and maintenance costs is to use a high-efficiency filtration system that separates solid particles and moisture from natural gas [2]. The results show that changes in key parameters such as particle diameter, fibre diameter and fluid velocity have a significant impact on filtration performance. Also, the filtration efficiency for particles with an average diameter of 2.5 and 5 to 8 microns is only about 83% and 89% to 92% [3]. From examining the performance of 4 different types of filter cartridges that were used to purify high pressure natural gas, it was observed that the decrease in the performance of the filters is related to the increase in the pore size of the cartridge layer [4].

The objective of this project is to simulate the flow of natural gas, considering a mixture of gas and sand, passing through a filter separator, inlet a gas reduction station, in order to calculate the efficiency and pressure drop of the filter under operating conditions. The results obtained from the software will be compared with the pressure drop data obtained from DP which is installed on the inlet of the filters of the gas reduction station, and the results were consistent. In previous research the material and dimensions of the dry filter medium were obtained based on the information provided in the gas standards. The fluid flow simulation is using ANSYS FELUENT 2021 software. This project dealt with a three-phase gas-liquid-solid flow due to the presence of solid particles (sand) and moisture in the natural gas pipelines. The Eulerian-Lagrangian method and Discrete Phase Model (DPM) and k-ε turbulent model have been used to investigate gas-solid three-phase flow. The operating pressure of the filter separator ranged from 150 to 250 pounds per square inch (psi), the permissible flow rate was between 400 to 2500 cubic meters per hour. Compressible flow is assumed. The results show that

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L10 - Filtration of heterogeneously composed slurries

Day: 14 November 2024
Time: 13:00 - 14:15 h
Room 1

Water and wastewater filtration with engineered pile cloth media: impact of microfiber variations and backing design

T. Fundneider*, R. Schäfer, U. Grabbe, Mecana AG., Switzerland


Pile Cloth Media Filtration (PCMF) is an established surface filtration process. It is considered as outside-in filtration process in which raw water flows through a Pile Cloth Media (PCM) whereby solids are removed as they get retained by the pile layer. The PCM consists of a filter-active fluidisable pile layer and a supporting non-filter-active backing. PCMF is able to close the gap between conventional surface or cake filtration and membrane filtration processes. Concerning PCMF technology, current trends are leaning towards finer 3D woven PCM, so that the removal efficiency is continuously being increased. Current PCM can be divided by their fiber thickness into the three different categories standard-, micro- and ultrafiber. Nowadays, microfiber (≥ 5 µm – < 10 µm) is the most common PCM in wastewater treatment applications for the removal of turbidity, total suspended solids, phosphorous, microplastic as well as powdered activated carbon. Continuous improvement of the engineered PCM is crucial for the success of the technology. The ...

Material and Method

The study was carried out in a parallel side-by-side test of PCMF drum units with 0.5 m2 filter surface. Both plants share the same influent stream originating from a secondary clarifier of a municipal WWTP after a SBR process. Operating parameters were equal for all tests and are based on the standard settings. Five different microfiber PCM were investigated in the studies, four PCM with the same backing design (PES-14, MF1, MF3, MF4; > 800 µm x 800 µm flow-relevant pores) and one with a different backing design (MF2; > 300 µm x 300 µm flow-relevant pores). The filament yarns of the investigated PCM showed variations in texturing (PES-14; MF1 – MF3) and fiber length (MF4) ...


PCM engineering aims to achieve high removal efficiency and improve operating conditions like backwash water amount, recovery, cloth resistance, and solids surface loading. PCM engineering has two components: the pile layer and the backing. The results demonstrate the ...

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Development of a stormwater filter from construction and demolition waste: initial flow properties in deep bed filtration

S. Jayasekara, N. Bolourieh, T. Kinnarinen*, Lappeenranta-Lahti University of Technology LUT, Finland

The topic of this study is flow properties of novel stormwater filter media prepared from various construction and demolition waste (CDW) materials. The main objective of the study is to find out the effect of filter media, including particle size and layer height, on the flow of water through the bed. It is important to recognize the most important parameters with laboratory experiments, to be able to produce stormwater filter media for long-term use in wetlands, where urban stormwaters are treated before their discharge to natural waters. In this study, hydrostatic pressure was used as the driving force and water was filtered through various bed layers made from CDW in a vertical column, where the pressure, i.e., the head, was kept constant during each experiment. The data was compared to theoretical values obtained by Darcy-Weissbach, Ergun, and Kozeny-Carman equations.

Different size fractions of two types of CDW concrete and brick waste materials were used in the column experiments. The results revealed that particles larger than 800 µm and smaller than 300 µm are unsuitable for the specific filter column used for the experiment. When particles are coarser than 800 µm, the superficial velocities become unrealistically high for a deep bed filter. Conversely, when particles are finer than 300 µm, superficial velocities are low, and probably not applicable in full-scale stormwater filters. Therefore, a series of experiments was carried out using two fractions of two different bed materials separately: 0.3 mm- 0.5 mm and 0.5 mm- 0.8 mm, and each fraction had four different bed heights: 30 cm, 40 cm, 50 cm, and 60 cm.

Morphology analysis of bed materials developed using CDW concrete waste revealed that the finer the particles, the more their shape deviated from the regular spherical particles, which is an important factor, when the results are evaluated against the theory. The particle sphericity was calculated using the Sauter diameter and the mean volume diameter of particles. The particle sphericity of both types of samples ranged from 0.5 to 0.9. In terms of two-dimensional determination of particle shapes, the circularities of the two samples ranged from 0.6 to 0.8 and 0.7 to 0.8, respectively. Microscope images of these two C&D concrete waste types revealed that the finer the particle size range, the higher the number of particles attached to each other, as usual.

The experimental data were used to calculate theoretical pressure drops using the Darcy-Weisbach, Ergun, and Kozeny-Carman equations. The calculated pressure drops across the bed materials indicated that the Kozeny- Carman equation gives the most reliable values in this case, close to the experimental pressure drops, followed by the Ergun equation. Moreover, the modified Ergun equation, which includes the particle shape factor, provides even more accurate pressure drops than the original Ergun’s equation. However, the calculated pressure drops via the Darcy-Weisbach equation are far lower than the actual experimental pressure drops. The most probable reasons for this could be that the Darcy-Weisbach equation does not consider the porosity, and the hydraulic particle diameter used to calculate Reynold’s number is not a fair representation of all particles in the actual particle size distribution range. These results highlighted that ...

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Urbanfilter - Modular filtersystem to retend tire wear and other solids from road runoff

D. Venghaus*, J. W. Neupert, M. Barjenbruch, Technical University Berlin, Germany

One negative environmental impact of driving that most people are not aware of is the amount of microplastics caused by tire wear while driving. Tire wear is one of the largest sources of microplastics entering the environment. In Germany alone, the amount of tire wear is over 100,000 tons per year.

Sewage treatment plants are in general capable of holding back microplastics. However, depending on the wastewater system, there are also road drainage systems that are not routed via the sewer system to a wastewater treatment plant. Frequently, road runoff is discharged directly into surface waters and poses a threat to natural waters and thus ultimately to us humans as well. Therefore, the AUDI Environmental Foundation is funding a project with the Technical University of Berlin, Department of Urban Water Management, which is researching an innovative filter system for road gullies that is intended to reduce the entry of microplastics and other pollutants into the sewer system and surface waters.

The project was launched in September 2020 and is scheduled to run for around three years. The System of URBANFILTER is modular. So far, nine different modules have been developed for the road, sewer and drain area, which, depending on the catchment area of a gully, can be configured to optimally hold back various pollutants such as microplastics, plastic packaging, cigarette butts, dog droppings or leaves.

Starting with a runoff channel on the road or a special asphalt cover, in the area below various filter baskets can be installed in the sewer and in the lowest area there is a fine filtration with a magnetic filter. The fact that more tire wear particles are produced in stop-and-go traffic or at traffic lights is also taken into account. An intelligent networking concept is considering parameters such as traffic volume, weather forecast and street cleaning.

The evaluation of various data enables a prognosis for the optimal time to empty the filter as well as the predictive use of street cleaning vehicles in order to remove the pollutants from the road before they are captured by the rainwater flowing off. Therefore the prototypes are tested and optimized on a special test stand at the TU of Berlin with the addition of different defined types of dirt particles and different rain intensities. Since beginning of 2022, a filter has now been deployed on a busy road in Berlin.

First intermediate results of lab and stress tests show that the URBANFILTER works effectively without clogging even under unfavorable conditions. It masters any sort of pollution – for example street sweepings, cigarette filters and microparticles – especially during light to medium rainfall. [AUDI Stiftung für Umwelt]1

Scientific data from the in situ operation will be presented.

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M07 - Ultrafiltration

Day: 14 November 2024
Time: 13:00 - 14:15 h
Room 4

Eco-design of membrane filtration through coupling life cycle assessment and process simulation

M. Hatoum*, J.F. Fabre, J. Albet, C. Vialle, C. Sablayrolles and P.Y. Pontalier, INRAE - National Institute for Agriculture, Food, and Environment, France

Traditionally, the sizing of chemical processes is based on technical and profitability criteria. However, due to growing climate concerns, process optimization must now consider other criteria, as highlighted by Azapagic in 1999. This paradigm shift requires taking into account not only economic viability but also environmental and societal impacts. Consequently, various methodologies have emerged, among which the coupling of process engineering and life cycle assessment (LCA) appears as a promising approach to simulate processes and their impact. Nevertheless, implementing this coupling is challenging for processes developed for biomass fractionation. These processes include unit operations (membrane filtration, chromatography, etc.) that are not as well described as processes like distillation in conventional software such as AspenÓ and SuperPro-designerÓ. Indeed, while membrane modeling has been studied for a long time, the developed models are generally based on the description of mechanisms and are not suitable for simulating the performance of a wide range of membranes. Therefore, in the classical process engineering approach, membrane performance is evaluated based on mass balance and requires experimental data. To address this gap in membrane filtration, it is necessary to have a model capable of simulating results ranging from nanofiltration to microfiltration. The modeling of porous membranes is generally based on Darcy's law, which allows calculating membrane permeability from the pore diameter and membrane thickness. The problems during simulation then arise from the variation in thickness between different types of membranes and the influence of fouling and the concentration polarization layer during filtration.

The objective of this study is to propose a new approach to facilitate the eco-design of biomass fractionation processes by coupling process simulation with ProsimPlusÓ software and life cycle assessment with SimaProÓ software. This approach is illustrated through a case study related to the purification of phenolic compounds by ultrafiltration.

The ProsimPlusÓ software allows for the simulation and scaling of various chemical engineering processes. Although it is not inherently suited for membrane filtration, it can be adapted by implementing a specific model within a dedicated module. In this study, a model (Equation 1) describing the performance of nanofiltration and ultrafiltration was introduced into ProsimPlusÓ and used to achieve a comprehensive analysis of technical performance under varying operating conditions. These simulations were linked to SimaProÓ to determine the influence of operational conditions on the environmental impact of the unit's operation....

The membrane filtration model was developed based on Darcy's law and modified to account for the effect of concentration polarization and fouling. The model parameters (a et b) were determined from experimental data, and then the model was applied to simulate the influence of pressure on the filtration performance of phenolic compounds by membranes with molecular weight cutoffs ranging from 1 kDalton to 100 kDalton. The influence of operating conditions was validated by experimental results, and then used to assess their impact on the environment by calculating membrane surface area and energy consumption.

The results indicate that...

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Operational performance of a pilot ultrafiltration unit for the treatment of ultra-concentrated brines

G. Scelfo*, R. Raffaelli, A. Cipollina, Palermo University; F. Vicari, ResourSEAs SrL, Italy; P. Serrano, I. Oller, Plataforma Solar de Almería-CIEMAT, Spain


Sea salt has been produced for centuries in saltworks, evaporating basins where seawater is concentrated in salt, until reaching saturation and crystallisation of food-grade NaCl. As a by-product, saltworks also generate exhausted waste brine with a concentration more than 20 times higher than seawater, commonly called bittern. This can be an important source of valuable minerals (Mg, K, Br, Li) recoverable through different integrated approaches, generally requiring a first purification step using Ultrafiltration (UF) for polishing and organics removal ( However, due to the unexplored nature of such application, the scientific literature is lacking of experimental information on the behaviour of ultrafiltration systems used as a pre-treatment for bittern processing.

The aim of this study was to characterise for the first time in the literature the peculiar behaviour of an UF pilot plant processing real bitterns, highlighting operating difficulties, flux enhancement possibilities and also collecting useful rheological data on real bitterns.

Materials and Methods

Different volumes of feed bittern from Trapani saltworks in Italy were treated in different UF tests at pressures ranging from 2 to 4 bar.

Tests were carried out in a UF pilot unit (Sepra, Italy, see Figure 1) equipped with a load centrifugal pump (Schmith) and a booster centrifugal pump (Lowara). Two asymmetric ceramic membranes with a total area of 0.7 m2 with a nominal cut-off of 300kDa were used. Pressures was monitored by two gauges. During the experiments, the flow rate, conductivity and temperature (on both permeate and retentate side) were measured.

To monitor the composition of the feed inlet, chromatograph analyses (Metrohm 882 compact IC plus end Methohm 930 compact IC plus) were performed periodically to determine any possible change in the ionic composition of feed bittern and permeate. To complete the characterization of the bittern, a novel study was conducted on the variation of bittern viscosity as ionic composition and temperature changed. To do this, temperature-varying viscosity tests were performed using an Ubbelohde viscometer and a thermostat bath.

To determine the organic compound inside the bitterns, COD analyses were carried out.

Results and Discussion

In this study, the influence of the main properties of the bitterns (chemical composition, organic content and viscosity) and operating pressure on the main process parameters of the pilot plant, i.e. flow and permeate flow rate, was investigated. These case studies are representative of the bitterns available during the different stages of salt production. To better investigate the process, 3 case study made up as different bittern having different ionic and organic composition, are investigated. For each case study, the main process parameters were analysed, such as variation in flux, viscosity, fouling and variation in treatment time for each batch as the operating pressure varied...

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Solvent-targeted plastics/oily streams recycling using ceramic membranes: life in plastic, not fantastic!

E. Pakkaner*, P. Vandezande, A. Buekenhoudt, VITO NV, Belgium

... Despite the substantial growth of the plastics industry, the rate of reuse and recycling of end-of-life plastics is shockingly low; an example would be the European market, as less than 30% of the 25.8 million tons of plastic waste generated annually is readily available for collection to be recycled[2]. Consequently, the remaining majority of the plastic waste is still landfilled or incinerated, which imposes a negative impact on the environment and raises a significant economic cost. Therefore, the preference for addressing plastic waste must be strictly implemented to be recycling, especially for the instances where re-using is considered unfeasible...

... In this work, we propose a membrane-based separation and purification platform for common waste plastics (e.g. PC, HIPS, PLA) upon their dissolution in various organic solvent systems. For that, a systematic screening of polymer/additive/solvent couplings was conducted via Hansen solubility methodology, to maximize the polymer recovery via optimizing the dissolution kinetics. Moreover, organic solvent ultrafiltration (OSUF) was explored to test the downstream purification performance of commercial ceramic UF membranes for the separation of high-performance plastics and industrially-relevant additives via simulated mixed-waste solutions. It was shown that...

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14:15h - Coffee Break


F11 - Advanced Methods to create Porous Filter Structures

Day: 14 November 2024
Time: 14:45 - 16:00 h
Room 3

ColdMetalFusion for porous metal AM filter applications

J. Reeh, C. Fischer, C. Staudigel*, Headmade Materials GmbH, Germany

The ColdMetalFusion (CMF) process is known for reliable serial production in metal AM with high part quality. In CMF, Headmade Materials combines standard PM metal powders with its proprietary binder system to form a powdery feedstock that can be processed into green parts on standard plastic laser sintering systems. The subsequent debinding and sintering step is again PM industry standard, and the part characteristics are fully comparable to MIM in terms of density and strength.

But CMF can also be used to produce porous parts with up to 50 vol% porosity. Even gradient porosity and parts with dense and porous sections are possible. The influence of feedstock, laser sintering parameters and sintering parameters on porosity and the potential in filter applications and medical industry will be shown in this study.

By developing new feedstock materials and new CMF processing parameters, CMF can also be used to produce components with a defined and gradual porosity for applications in the fields of filtration, medical technology, and hydrogen generation. The focus here is not on the mechanical properties, but on the porosity characteristics in terms of pore size, pore shape, homogeneity, flow resistance and surface.

With CMF the porosity can be adjusted in three ways: feedstock, laser sintering and sintering. Especially the laser sintering offers a new and unique dimension to adjust the porosity compared to MIM and competing 3D printing technologies, because the porosity in the green part can already be adjusted and gradual porosity gradients can be implemented within one part using various exposure strategies. This offers many possibilities for potential new applications.

Creating porous structures with CMF standard feedstock

In the following, the possibility of producing porous structures with CMF standard feedstock is examined. The two main influencing factors that determine the degree of porosity are ...

One possibility to produce more porous structures is the use of ... within the feedstock material, as these particles tend so have a lower sintering activity [4], especially at lower sintering temperatures. Figure impressively illustrates this effect by comparing the green and sintered density as well as the scaling factor of CMF standard feedstock (fine metal powder) and optimized CMF feedstock (coarse metal powder).



Figure 3 shows exemplary Ti6Al4V parts like a technical filter with highly porous filter areas which are embedded within a honeycomb-shaped support frame, as well as the acetabulum-component of a hip joint implant which is printed with a porous outer shell and a dense inner surface...

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Piperazine diffusion controlled interfacial polymerization for regulating thin film composite nanofiltration membrane

J. Wang*, Y. Ye, N. Qiu, Z. Qiu, Y. He, F. Liu, Ningbo Institute of Materials Technolog, China

Interfacial polymerization is a widely used method for fabricating nanofiltration and reverse osmosis membranes. In this process, monomer diffusion played an important role for regulating the structure of obtained polyamide layer. Many strategies have been reported to control the monomer diffusion, such as viscosity manipulation, interlayer strategy, surfactant adding, co-solvent strategy et al.

Among these, co-solvent strategy is easy and most fit for the current industrial production line of nanofiltration membranes. However, the underlying mechanism for its effect on the monomer diffusion and the corresponding structure of polyamide layer is still unclear and contradictory in literatures. In this study, we report a co-solvent induced piperazine diffusion flood behavior through interfacial co-solvent extraction effect.

The reason was mainly caused by the temporary interfacial enrichment of the co-solvent (acetone). We also tested different co-solvent effect, mainly two phase immiscible and one phase immiscible co-solvent. Experimental and molecular dynamics simulation (MD) results were obtained to explain the acetone interfacial extraction effect.

Moreover, the prepared nanofiltration membranes exhibited improved ..., which were better than many of the recorded membranes. This study provided a new idea for the co-solvent effect in interfacial polymerization and promising guidance for the preparation of superior nanofiltration membranes.

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ISO 21368:2022-03 – Adhesives Guidelines for the fabrication of adhesively bonded structures and reporting procedures suitable for the risk evaluation of such structures - How it effects application in filtration

F. Steegmanns*, Stockmeier Urethanes GmbH & Co.KG, Germany

In March 2016, The German Institute of Standardization (DIN) has launched the new DIN 2304-1 Adhesive bonding technology - Quality requirements for adhesive bonding processes. This standard has since been incorporated into ISO 21368 as part of a routine revision. The DIN EN ISO 21368:2023-05 is currently in the commenting phase and will be published in August 2024.

The well know quality standard, DIN EN ISO 9001 stipulates the minimum requirements for an organisational Quality Management System (QMS); however, this is a general standard and not specified to the requirements of different technology processes. The DIN 2304-1 and new the DIN EN ISO 21368:2023-05 is a technological specification especially for bonding processes to be used in conjunction with ISO 9001 and focuses on three core elements, classification of adhesively bonded joints, personal qualification for bonding processes and verification management.

Following the adhesives bonding process chain, users of this standard are able to improve the quality of their products and the end application. This presentation gives an overview about the requirements, the general idea behind the new standard and how users will benefit. Standards (DIN / EN / ISO) are no legal norms, but there are private technical regulations with recommendatory character and describe the “State of Art”.

It can be obligated due to a business transaction when clients require that and in a legal dispute (case of damage) standards can be taken into account. Following the scope the standard DIN EN ISO 21368:2023-05 is valid for all structural adhesively bonded joints, i.e. loadbearing and adhesive bonds, independent of which kind of adhesives, curing or application process is used.

Looking at the international success story of a similar standard (DIN 6701) for the railway industry, and the standard DIN 2304-1 in industrial applications, DIN EN ISO 21368:2023-05 is expected to also become of worldwide importance soon.

The quality of modern adhesives allows ...

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G15 - Modelling and Simulation III

Day: 14 November 2024
Time: 14:45 - 16:00 h
Room 2

Two ways to optimize the microstructure of a filter for gas-particle systems using adjoint (related) methods

N. Jüngling*, J. Pospichl, J. Niessner, Heilbronn University of Applied Sciences, Germany

Clean air and water are increasingly in focus, while the demand for energy-efficient solutions to address these issues is growing. Filter development must rise to this challenge. Filters should be used in a resource-efficient way. This can be achieved by precisely matching filters to the application, both in terms of particle size distribution and the conditions of the fluid flow to be treated. Conventional filters often consist of one or more layers of filter media, which are either woven or composed of tangled fibers. The efficiency of these filters depends mainly on the tightness of the fabric.

The development of additive manufacturing has made great progresses in recent years. Using this technology, filter manufacturing is no longer restricted to conventional methods. In addition, computers have become more powerful and can carry out numerical flow simulations in a short time. The limits of additive manufacturing in terms of material and resolution have not been reached yet. A great potential for the developed method is expected here in the future.

The aim of this work is to present two methods to optimize filter structures with respect to the filtration efficiency and the pressure loss: first a simple geometry-based shape optimization of initial structures with the adjoint method and second an Eulerian Multiphase approach inspired by the adjoint method.

Both approaches are based on the same workflow, but are different with respect to the cost function used. The first steps are application-dependent: Creating an initial geometry in Computer Aided Design (CAD), meshing the initial geometry in Computational Fluid Dynamics (CFD) and determining pressure loss and separation efficiency for e.g. pollen separation in car ventilation systems. The cells at the fibers are then varied by mesh deformation until an optimum is found. While the first method requires cost functions that can be derived to run the adjoint solver, the second method can use arbitrary functions. These cost functions have to account for the different separation mechanisms and the pressure loss. The combination of the sensitivities was realized by an algorithm. Lagrange and DEM simulations were performed to determine the percentage of impaction and interception in the total separation efficiency. Physical prototypes of the often bionic-looking optimized structures can be generated using additive manufacturing.

The whole workflow was successfully tested for ...

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The new python interface for customized automated pre- and postprocessing of 3D microscale filtration simulations with DNSlab®

A. Ataei*, V. Puderbach, K. Schmidt, IT for Engineering (it4e) GmbH, Germany

DNSlab is a software for analysis and direct numerical simulation of fluid and particle flows by means of 3D models especially of microscale porous structures.

The new DNSlab Python Interface was introduced with the first DNSlab release in 2024, Release2024a. It enables DNSlab users to automize and customize the pre- and postprocessing of DNSlab applications. The interface is provided in the form of a package of classes and functions which are imported in the user’s python code, and which enable to read and write DNSlab input and output data. The basic working principle is that by the user’s python code, DNSlab runs are prepared, executed and evaluated. In particular for the evaluation, Python’s comprehensive plotting capabilities are applicable.

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Digital twin deployment for airborne molecular contaminants (AMC) filter life cycle prediction

A. Chakraborty*, F. Belanger, R. Gipson, Entegris, Inc., USA

Airborne Molecular Contamination (AMC) is a critical issue for numerous state of the art manufacturing processes. These contaminants degrade features and effect yield in the semiconductor manufacturing process, where feature sizes continues to shrink.

AMC chemical filters play a pivotal role in removing AMC contaminants and provide purified air to SEMI cleanrooms, which is a key requirement in generating quality products. Long filter lifetime is desired, and design optimization plays a central role in filter development. Filter removal efficiency (RE) and life cycle are critical design parameters. However, it is challenging to obtain removal efficiency experimentally, particularly at very low gas concentrations, due to long test time, high experimentation cost and logistical limitations. Although computational modeling is an efficient means to generate predictive models, long computational lead time and inability to capture a live Failure Mode Engineering Analysis (FMEA) analysis are shortcomings.

The digital twin (DT) is a machine learning model which is a virtual representation of real word entities and processes, synchronized at a specified frequency and fidelity. It can track the past, provide insights into the present and predict and influence future system behavior and can offer live, system-level simulated prediction with real-time data inputs. Therefore, DTs offer a unique opportunity to study virtual and physical systems, either separately or together.

This study was a pioneering effort to successfully develop and deploy Digital Twin technology in the AMC filter optimization process. A static and dynamic Digital Twin were developed from initial validated Computational Fluid Dynamics (CFD) model of a specific AMC chemical filter. The newly developed Twin model was able to predict the filter performances instantly along with live FMEA by its developed virtual sensors which critically can help filter optimization process by reducing cost of ownership significantly...

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L11 - Multiple Contaminant Removal and Particle Fractionation

Day: 14 November 2024
Time: 14:45 - 16:00 h
Room 1

Expansion of Disruptor®’s water filtration capabilities utilizing functionalized additives

T. Showers*, C. Lack, R. Rock, E. Nelson, Z. Winek, Ahlstrom, USA

Disruptor® water filtration technology was first introduced over a decade ago as a new innovation utilizing fibers and charge to achieve 4 log reduction of virus in gravity flow and pressurized water applications. Numerous studies have been conducted to establish multiple contaminant removal capabilities of standard Disruptor®. These have increased the understanding of Disruptor®’s ability to remove E. coli bacteria, legionella bacteria, endotoxin, humic acid, Iron (II & III), and trace pharmaceuticals (PCBs). What started as a defined and limited technology continues to evolve into a versatile product line able to meet today’s challenges within the water filtration industry.

While Disruptor® has proven its viability on the market for the past decade, recent developments and industry preferences have seen the technology enter a new phase of enhanced development. This includes expansion of filtration capabilities accomplished by introducing functionalized additives that have a synergistic effect when used in conjunction with traditional Disruptor® technology. Disruptor® technology utilizing these functionalized additives provides the biological removal efficiencies known to be achieved by Disruptor®, while also providing enhanced removal of chemical contaminants such as chlorine, chloramines, soluble and insoluble lead, arsenic, and select species of PFAS. Removal efficiency data and capacity curves are used to validate performance criteria.

Increased demand for higher flow material for use in gravity flow applications has led to the creation of a more open media that takes advantage of functionalized additives in order to retain high efficiency virus removal with a larger pore structure. This particular functionalized additive has also led to the development of a compostable prefilter that will not require lamination due to its high mechanical strength and pleatability. A growing social and commercial demand for sustainable products has been a driving force in this recent innovation.

With newly emerging contaminants creating concern for consumers, Disruptor® has proven to be an adaptable technology capable of meeting ever-changing market demands. These developments are focused on the ability to provide water filtration solutions based upon traditional Disruptor® technology, now including synergistic functionalized additive options in both Disruptor® filtration media and pre/post filters.

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Investigation on particle motion and fractionation in a crossflow with superimposed electrical field

S. Paas*, S. Antonyuk, Kaiserslautern-Landau (RPTU), Germany

The success of technical processes with suspensions is strongly dependent on the particle properties. The increasing demand for narrow particle size distributions and known physical and/or electrochemical properties, especially for fine particles < 10 µm is leading to new processes which can provide such dispersed particles. [1]. Existing separation processes like hydrocyclones, centrifugal applications or crossflow fractionation face the challenge of achieving the desired particle size without a high energy and/or time consumption.

In this contribution, a cross-sectional fractionation technique is being presented, which is a promising method for the highly specific separation of micro and submicron suspensions. A discontinuous operation was developed from Altmann and Ripperger [2] and was further elaborated by Loesch et al. [3, 4]. The method not only allows fractionation with regard to the particle size, but also the charge of the individual particles, therefore a multidimensional particle separation. The fractionation process is based on a crossflow of a particle carrying fluid (feed) and particle-free water (filtrate) (cf. Figure 1). Both flow parallel, upwards against the gravitational field through a separationmodule. The actual fractionation takes place at the separationmedia, located between the two main channels...

For laminar flow conditions, the mainly acting hydrodynamic forces can be divided into two characteristic forces, the drag force FD and the lift force FL. The drag force acts along the flow direction, the lift force orthogonally to it. Based on the size-dependent hydrodynamic forces bigger particles are transported into the core flow. To separate the smaller particles in the wall-near boundary layer, which are less influenced by this effect, a separation medium with pores bigger than the particle size is adjusted. A very small differential pressure between the two channels allows a suction of a small volume of the suspension flow into the filtrate channel, containing only small particles. The sedimentation also occurs, but is not directly involved in the fractionation process. By adding a superimposed electrical field, which is acting orthogonally to the main flow, the particles are subjected to an additionally electrophoretic force FE. The magnitude and direction of this force is determined by the particle properties, in particular the electrophoretic mobility and is competing to the hydrodynamic force.

In this present work the investigation of the hydrodynamic fractionation and the particle deflection in the electric field is carried out.....

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A novel analysis method for hydrocyclone test data and reliable scale - up by using the CYCLONPLUS Software

I. Nicolaou*, NIKIFOS, Cyprus

In this paper, a novel method for the Analysis of Test Series data carried out with hydrocyclones by using the CYCLONPLUS Software will be presented (usually test cyclones in laboratory scale). The analysis of test data is based on practice oriented mathematical models, which consider the complex phenomenology by the use of adaptation parameters. There are 10 adaptation parameters, which are specific for the system suspension and hydrocyclone family. To one hydrocyclone family belong apparatuses with different diameters of the cylindrical part but with the same specific geometrical parameters: length to diameter (L/D), cylindrical length to diameter (l/D), inlet diameter to cyclone diameter (Di/D) as well as overflow diameter to cyclone diameter (Do/D). It will be explained that only 3 of the 10 adaptation parameters are the most important and that for the other 7 parameters default values can be used. Of course, the program enables the determination of all 10 parameters from only 4 tests. From every test, by default the following parameters have to be measured and entered in the Analysis module: Feed und underflow volume rates (Q, Qu), Pressure drop (Dp), underflow orifice diameter (Du) and solids mass content of the overflow (cmo). Due to the theory-based diagrams of the Analysis module, the quality of the measurements can be judged, and only correct measurements can be used for the determination of the above-mentioned adaptation parameters.

Based on the adaptation parameters, which are determined from the analysis of the Series test data it will be demonstrated how by using these parameters a performance calculation or the design of an industrial unit can be performed in a user-friendly way.

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M08 - Reverse Osmosis

Day: 14 November 2024
Time: 14:45 - 16:00 h
Room 4

Water transportation in osmosis membrane at ultra high pressure

H. Guo*, L. Storm Pedersen, SaltPower ApS, Denmark

Osmotic pump, controls not only drug release as a novel drug delivery systems (NDDS) in humans and animals, but also energy release as a novel green energy system (NGES), by mixing fresh water with pressurized salt water through a semi-permeable membrane. SaltPower’s osmotic pump is based on pressure retarded osmosis (PRO) membrane process, utilizing saturated brine at relative high hydraulic pressure. In this process, water molecular migrating through membrane from fresh water side to salt water side is primarily driven by the transmembrane pressure (TMP), which is the difference between osmotic pressure and the hydraulic pressure. The osmotic pressure is dependent on the salt concentration at defined temperature, while the hydraulic pressure applied on salt water side is proportional to work but retards osmotic pressure and eventually adversely affect water migration. In theory, the ideal hydraulic pressure is half of osmotic pressure to obtain the optimum water permeation and the highest energy output. It says 200 bar in case of NaCl solution. Currently, membrane has never been operated at such high pressure, and the corresponding water transport behavior is rarely investigated neither.

Reverse osmosis (RO) membrane is the high pressure type in membrane category, and the thin film composite (TFC) RO membrane is normally selected as the object for PRO researches. In many cases, the thin film (TF) layer is cross-linked polyamide (PA), which has no measurable pores. Therefore, such TF is considered as non-porous polymer, and a solution-diffusion (SD) model is applied to describe mass transfer in TFCPA. It shall be noticed that a solution-friction (SF) model becomes popular recent years which critically challenges SD model by viewing the PA network as water channel with sub-nanometer pores, and water transfer mechanism is hydraulic pressure gradient rather than diffusion. Even though, the water flux expressed in SF model is equivalent to SD model, which is derived from Fick’s Law, in RO process, it is described as...

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Investigating the dynamics of a hybrid closed-cycle reverse osmosis and adsorption process for PFAS removal

J.B. Roman*, A.J.B. Kemperman, W.G.J. van der Meer, J.A. Wood; University of Twente, Netherlands

Previous research has established that dense membranes are very good at blocking passage of several PFAS [1]. Even very low molecular weight PFAS compounds show high rejections (>98%) in reverse osmosis and some nanofiltration processes[1]. Although permeate water can be produced with PFAS concentrations below regulatory limits, PFAS remains in the concentrate stream meaning none is necessarily removed from the water cycle if the concentrate is discharged to the environment. The concentration of PFAS in the concetrate stream is higher than in the feed stream however, making removal from the concentrate stream more feasible.

Recent research (2021) by Franke et. al. has shown the potential of combining membrane filtration and adsorption processes for PFAS removal from water streams [2]. Depending on the PFAS species being removed, either activated carbon or anion exchange resins showed better performance as adsorptive materials. Long-chain (>C6) PFAS compounds adsorb well on both activated carbon and anion exchange resins. Short-chain (<C7) PFAS however adsorb poorly to activated carbon due to repulsive electrostatic interactions dominating for these compounds.

Furthermore, the wide array of sources and locations where PFAS remediation is required means there is no one-size-fits-all solution. To address this, we investigate the possibility of using filter cakes as adsorption media, since these can be tailored to the specific needs of the feedstock to be treated. Besides being flexible in operation, this approach is also more future proof, since equipment will not have to be retrofitted when new concerning pollutants are discovered, which can require new adsorbent materials. We also found that whilst adsorption in cake layers is commonplace in industry (e.g. for the bleaching of edible oils), we could not find any studies on the effect of the buildup of the filtration cake on its subsequent use as an adsorption layer. Therefore, we decided to investigate the effect precoat and filter aid filtration on the subsequent adsorption of various PFAS’ over time.

In this work we combine ‘closed-cycle reverse osmosis’ (CCRO) with simultaneous adsorption in a cake layer for PFAS removal at environmently relevant concentrations. By doing...

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Nanofiltration as an alternative barrier to reverse osmosis for the removal of dissolved contaminants in water reuse applications

M. Alhussaini*, King Abdulaziz City for Science and Technology, Saudi Arabia; A. Achilli, University of Arizona, USA

The increasing demand for drinking water has led to the adoption of unconventional water sources, like water reuse. Reverse osmosis (RO) and Nanofiltration (NF) membranes are effective barriers against trace organic contaminants for potable water reuse applications. However, the use of RO is being challenged by NF, primarily due to NF’s potential to achieve similar contaminant passage rates as RO but with higher productivity and lower energy requirements. NF can be more efficient implementation for organic pollutants removal. As the RO generally achieves ≥95% rejection of NaCl, NF membranes have relatively loose structure allowing more water permeation and producing low-saline concentrate which results in lower energy consumption. This study compares NF with RO membranes on contaminant passages and energy consumption for potable water reuse applications.


Ultra-filtered treated reclaimed wastewater was used to study the transport of contaminants through NF and RO membranes for potable water reuse applications with focus to assess NF as a sustainable alternative to RO. This study compares the permeate water quality of NF and RO membranes to evaluate their water permeability and solute rejection passage in bench-scale systems. Additionally, this study provides details on the organic compounds permeating through the membranes in terms of molecular weight, hydrophobicity, and TOrCs rejection. Subsequently, engineering-scale experiments employing NF were used to evaluate the rejection rates of contaminants and estimate the energy consumption.


Reverse osmosis and nanofiltration membranes were tested in bench-scale and pilot scale systems using UF-filtered reclaimed wastewater. Ion chromatography (IC) and inductively coupled plasma mass spectrometry (ICP-MS) were used to measure anions and cations concentration. For organics, Total Organic Carbon analyzer (TOC) was used to measure TOC concentration, size-exclusion chromatography (SEC) for molecular weight, and UHPLC-MS/MS for quantification of trace organics.


RO and dense (NF90) and loose (NF270) NF membranes were tested in both bench-scale and pilot scale systems utilizing UF-filtered reclaimed wastewater. The highest solute passage was observed ....

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16:00h - Coffee Break

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