Conference Programme Filter

Use the Select-Fields below to filter the programme.

Thursday, 10 March 2022



M5 -


Opening Session

Day: 22 October 2019
Time: 10:15 - 10:45 h
Room 1A


Plenary Lecture

Day: 22 October 2019
Time: 10:45 - 12:00 h
Room 1A

Session Chair:
Prof. Eberhard Schmidt

Centrifugation – Key technology for solid/liquid/liquid separation

Dr. Harald Anlauf, Karlsruhe Institute of Technology (KIT) - Germany

Particle/liquid separation can be focused on very different tasks like thickening, purification, fractionation, sorting, extraction or deliquoring. The separation has to be mastered for wide ranges of particle size and shape, specific solid and liquid weight, slurry concentration, chemical composition and rheology, flow rate, process and technical boundary conditions and last but not least demands on the separation results. To solve all the separation problems beside centrifuges many physically different methods and in total more than 2000 different apparatuses and machines are available at present, but always new developments can be observed.

The necessary pressure difference for separation can be generated either by gas, mechanical and hydraulical pressure or by hydrostatic and centrifugal pressure. This causes for cake filtration some fundamental physical differences between pressure filters and filter centrifuges. These physical differences and further aspects have to be considered, when the question has to be answered, whether a pressure filter or a centrifuge may be the better option to solve a specific separation problem. Beside filtration by centrifuges with a perforated bowl centrifuges with a solid bowl are able to realize density separation. Thus both fundamental separation principles can be covered by centrifuges. This enables for centrifuges not only solid/liquid but in addition solid/liquid/liquid or liquid/liquid separations.

Centrifuges can be applied very flexible to solve most different separation problems and beside speed the centrifuge design parameters are decisive to adapt the machine best possible to the specific separation problem. The improvement of the centrifugal technology is a dynamic process and many technical innovations as well as theoretical progress can still be observed. One important issue for centrifuges represents the reduction of the necessary energy demand for the separation process, because the physical principle of using mass forces requires an acceleration of the total slurry mass to the circumferencial speed.

To increase the centrifugal separation efficiency not only the centrifuge itself has to be considered but in addition diverse possibilities of slurry pre-treatment and apparatus combinations. Last but not least beside centrifugal forces gas differential pressure and thermal drying can be implemented in some centrifuges additionally to realize a synergistic hybrid separation concept.


K1 - Keynote Lecture I

Day: 22 October 2019
Time: 13:00 - 14:15 h
Room 1A

Session Chair:
Dr. Harald Anlauf

Digitalization of Centrifuges – Helpful or senseless?

Prof. Dr. Hermann Nirschl, Karlsruhe Institute of Technology (KIT), Germany

During the last years digitalization was and is still a major topic in all companies of the process and machinery industry. Besides all business development procedures, the digitalization of processes seems to be a rather challenging task. Although in automotive or aviation industry the future of manufacturing can already be oberved, in the chemical and process industry there is still a long way to go. Digitalization in the industrial sense means in general to develop a ‚digital twin‘ of the process as a digital copy. The big advantage of such a digital twin is the possibility to extensively control not just the single machine by its own but also to control the whole process chain to ensure the quality of the final product at any time.

In general the development requires a simulation of the machine behavior with the material properties, not only for the stationary but also for the dynamic case. The main challenges for an extensive digitalization are the complex material behaviour which is very difficult to describe in a simulative environment and the complex geometries of the machines combined with the complex process behaviour. For the material behaviour, characterisation devices have to be developped which help to implement the material properties directly into the simulation procedure. This is necessary because a direct numerical simulation on a micro scale level where each particle is approximated is far too time consuming. So with multiscale simulations it is possible to derive short cut models which allow to simulate the whole process chain within seconds or even faster. This gives the possibility to simulate not just process parameters but also raw material or energy consumption relations. Those relations could be directly used to optimize the whole process according to inverse simulations.

Finally a digital twin could also be used not even as a 3D design or training tool, it is also valuable to study process conditions with different material parameters or critical conditions. So digitalization is not just a strategy to improve business tools, it will also be a big step to secure and reliable processes. The talk will show the procedure for the development of a digital twin for different kind of centrifuges and discuss the valuable advantages of digitalization for typical separation and classification processes...


F1 - Enhancement of Filter Media by Surface Treatment

Day: 22 October 2019
Time: 13:00 - 14:15 h
Room 4B

Session Chair:
Dr. Christine Sun

Advances in plasma deposition of functional nanocoatings for filtration applications

F. Legein*, S. Loulidi, 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 manufacturing of filtration media and elements to achieve functionalities such as hydrophilic, hydrophobic or oleophobic. Improvements in process and machine design allow to deposit the 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 or nanofibers a clear competitive edge. The presentation will discuss advances in some of the main plasma nanocoating applications adopted on industrial scale in recent years.

The presentation will start with a short introduction of 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. An overview will be given of typical coating chemistries used for such coatings.

Subsequently advances will be discussed using real industrial case studies. One case study will discuss the use of hydrophilic nanocoatings for culture growth media. Another case study will review the use of similar nanocoatings for blood filter media. One of the key areas of interest is the oleophobic coating of nonwoven HEPA filter media. Advances in process chemistry allow to deposit coatings which enhance the filter efficiency while maintaining the pressure drop, helping in further reduction of the ecological footprint.

Also advances in durable water repellent coating of membranes for use in sporting and outdoor jackets will be discussed. Last but not least the presentation will give insight on the industrial application of atmospheric plasma for coating of release liners. The presentation will conclude with an overview of the environmental benefits of plasma technology. Its potential for wider industrial spread will be demonstrated with cost analysis of a real industrial case.

Filter cloths: Bluetes anti-abrasion resin

D. De Angelis*, L.I. Balzaretti, M. Motta, M. Reginato, Testori S.p.A., Italy

Abrasion is among the more critical factors affecting the useful life in operation of a filter cloth installed on a filter press. The mining and metal refining industry represents one of the more challenging processes in which solid-liquid separation is performed, due to aggressive chemical environment and for the physical nature of the suspended solids in the inlet sludge. Further crystallization of dissolved solids also contributes to the potential mechanical failure of the filter media. Abrasion is more likely to occur in correspondence to specific localized areas of the filter cloth. By the frame and bosses the cloth transitions from the filtering area to the non-filtering one. Such points of discontinuity are therefore the more exposed to abrasion and thus prone to mechanically fail due to prolonged wear effect. Over the years several technical options, ranging from textile-based reinforcements to surface coatings, have been promoted by filter cloth manufacturers and adopted by the market in various industries. Among their major drawbacks are the creation of an over-thickness that might not be accommodated within the equipment design or poor resistance to withstand aggressive chemical environment. In this article we demonstrate the effectiveness of BlueTes, a special aliphatic polyurethane resin developed by Testori as an impermeable and chemically resistant anti-abrasion coating. Comparative laboratory tests have been conducted on several samples....

Surface modification of RO membrane by grafting hydrophilic switchable polymer brushes

M.A. Abbas, N.M. Ahmad*, National University of Sciences and Technology (NUST), Pakistan

The grafting of stimuli responsive polymer brushes has been explored on the surface of various membrane using surface-initiated atom transfer radical polymerization (SI-ATRP).

Surface morphology, permeation flux, salt rejection and pore sizes are investigated as function of external stimuli particularly the pH effect.


G1 - Air Filtration

Day: 22 October 2019
Time: 13:00 - 14:15 h
Room 4A

Session Chair:
Prof. Dominique Thomas

Back cleanable air filter elements for critical dust systems – US HEPA, IFA H and EN1822 HEPA

M. Wilkens*, Hengst SE, Germany

Health and safety regulations in the construction work are becoming more and more important. This trend is visible in new regulations for the occupational limit values of, for example, silicate dust systems in the last years (Occupational Safety and Health Standards 1910.1053; 2016).

State of the art filter materials for critical dust systems (HEPA and IFA H (EN60335) filter elements) are micro glass fibre based materials. The big disadvantage of this type of materials is the filter mechanism itself – depth filtration. Due to this, the lifetime of such elements is extremely low, especially if high dust loading rates prevail, like in construction work applications. A regeneration/ back cleaning of such materials is from the technical point of view not possible.

The low lifetime of this type of materials is one reason for the OSHA 126.1153 regulation, which requires for a lot of construction applications a filter element that has to be cleanable and should reach an efficiency of >99% or a HEPA efficiency of 99,97% @0,3µm (monodisperse).

The company Hengst SE as leading supplier of air filter elements for professional vacuum cleaners, which are used in such construction work applications, set oneself the target to develop a cleanable filter element with the filtration classes US HEPA, EN1822 HEPA and IFH class H (EN60335).

During this development many influencing parameters are identified, like the filter material composition and structure, the pleat pack construction and the interface of the filter element to the vacuum cleaner...

Energy efficient media solution for eurovent A+ rated filters

C. Desquilles*, P. Blanckaert, Lydall Performance Materials SAS, France; R. Bharadwaj, Lydall Performance Materials, USA

Eurovent energy rating RS4/C/001-2019 has been updated beginning of 2019. It is not based anymore on efficiency measured according EN779, it is linked to efficiency measured according ISO 16890.

Lydall Performance Materials developed a range of fiber glass media with improved pressure drop. The complete range of grades (from efficiency ePM2,5 50% to ISO ePM1 80%) has been tested flat sheet. In parallel V bank filters have been produced with the complete range of HD products. Efficiencies according ISO 16890 of the filters have been tested and compared to the efficiencies of media flat sheet.

Filters have been tested according Eurovent RS4/C/001-2019 for their energy rating.

The LydAir® MG fiberglass media in our portfolio (HD range) will allow the filter manufacturer to obtain the desired ePMx efficiency on the complete filter element at the lowest pressure drop. This low initial pressure drop and the optimized increase of pressure drop during the dust loading with ISO fine dust is consequently giving performant energy rating of the filters when measured according Eurovent RS4/C/001-2019...

Filtration performance of PAN fiber produced by centrifugal spinning using DMSO and DMF as solvent

A.I. P. Salussoglia*, M.L. Aguiar, Federal University of São Carlos; E.H. Tanabe, Federal University of Santa Maria, Brazil

Polyacrylonitrile (PAN) has been used as fiber for improves particulate matter collection efficiency, be good stability and mechanical properties. Polar solvents is commonly used to solubilize PAN and dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) are frequently used as solvents.

The aim of this work was to evaluate fiber diameter, pore area, superficial porosity and filtration performance of filter medias covered with fibers produced by Forcespinning (centrifugal spinning method) from PAN dissolved in DMF and DMSO...


L1 - Particle and Slurry Characterization

Day: 22 October 2019
Time: 13:00 - 14:15 h
Room 1B

Session Chair:
Dr. Anthony Stickland

Identification and size measurement of plastic microparticles

R. Ben Aïm*, N. Petillon, IFTS - Institute of Filtration & Techniques of Separation; C. Causserand, University of Toulouse, France, I. Robertson, Perkin Elmer Ltd, UK

Plastic microparticles are today a very important environmental issue.

Impressive photos show their very visible presence in oceans. However, their discrete or invisible presence in lakes, rivers and aquifers is becoming an important concern including public health issues.

To date, there is not a consensus about a general definition of plastic microparticles. However the definition proposed by Frias et al. (2019) integrates all the specificities of these particles: “Microplastics are any synthetic solid particle or polymeric matrix, with regular or irregular shape and with size ranging from 1μm to 5mm,of either primary or secondary manufacturing origin, which are insoluble in water”. Recently the proof of the existence of a nano-size fraction in waste water resulted in this additional definition of “nanoplastics”: particles resulting from the degradation of plastic objects and having a colloidal behaviour with a size between 1 nm and 1 µm”...

....Several methods and analytical techniques like light microscopy, laser diffraction, micro-Fourier Transformed Infrared Spectroscopy (μ-FTIR)), micro-Raman spectroscopy have been used recently as imaging flow cytometry. Most of these methods have size limitation and provide results only above 10 or 20 microns. Additionally, in the size range where a comparison is possible, the results are quite different: this clearly appears in the results presented in a recent thesis concerning the microplastics produced by personal care products and kitchen scourers.

From other part, the submicronic fraction of microplastics is quite unknown.A method and a test rig for assessing the efficiency of filters in the micron and submicronic range was recently developed. Recent results concerning the retention of microplastics by cartridge and membrane filters using this test rig will be presented.....

Measuring solid/liquid separation of viscous polydisperse suspensions at gravity and in centrifugal field

T. Sobisch*, LUM GmbH, D. Lerche, LUM GmbH / Dr. Lerche KG, T. Koch, Kronos International Inc, Germany

In first approximation, settling may be easily described by Stokes law taking into account dynamic viscosity η and in case of high solids concentration, a suitable hindrance function. In centrifugal field centrifugal acceleration has to be used instead of gravitational acceleration.

Settling studies based solely on visual inspection have been increasingly replaced by instrumental methods since decades. Accelerated stability testing using centrifuges is applied in many formulation and research labs as a standard protocol. This assumes a good correlation with results obtained by visual observation as well as with results obtained at earth gravity, however, related investigations on real world complex dispersions are rare. In this work settling of aqueous suspensions of technical grade titania samples was evaluated in viscous but Newtonian liquids (aqueous solutions of sucrose or glycerol) in the regime of high particle concentration (up to 28 % v/v) as well as in the regime of low particle concentration (< 0.1 % v/v). Results obtained by visual observation at gravity and by instrumental measurement were compared using STEP-Technology both at gravity (LRPSA/LR-X-Ray) and in centrifugal field (LS)...

Off- and In-line monitoring of processed milk by MRS-Technology

P. Dumeier, D. Lerche*, LUM GmbH; K.-H. Mittenzwey, G. Sinn, Optosphere Spectroscopy GbR, Germany

Monitoring of size and material composition is essential for all separation unit processes with a clear preference for in-line solutions. In this regard approaches allowing control of both size and material composition are advantageous.

This paper introduces MRS (multireflectance spectroscopy) as a promising new technique to serve this goal. It is based on use of backscattering and spectral reflectance signals over a very broad wavelength range (UV-VIS-NIR). The signals cover information on scattering and absorbing particulate and dissolved compounds and are also influenced by the size distribution.

The paper presents the basic underlying principle and its validation.

To highlight the potential of the method different applications related to the dairy industry and biotechnology are presented.

Acknowledgement – We thank Bundesministerium für Wirtschaft und Energie for financial support of the project EP131445


M1 - Membrane Design and Characterization

Day: 22 October 2019
Time: 13:00 - 14:15 h
Room 2

Session Chair:
Prof. Allan Kuo-Lun Tung

High-pressure operation of spiral wound membrane elements: The relevant aspect of permeate channel fluid dynamics

C. Kleffner*, G. Braun, Technical University Cologne; S. Antonyuk, Technische Universität Kaiserslautern, Germany

As the industry is increasingly forced to enhance concepts concerning water reuse and the recovery of valuable substances to strive for a waste water-free production, viable methods for the treatment of high osmotic solutions are required. In terms of the sustainable approach of a minimal liquid discharge, membrane based processing turns out to be a suitable option.

Reverse osmosis (RO) is a broadly developed and well-established technology for the treatment of brines. As long as the osmotic pressure of the treated salt solution allows a feasible operation, reverse osmosis remains the preferred choice due to its persuasive energy efficiency. Extending the application of the pressure-driven reverse osmosis process towards higher operating pressures is a reasonable approach as the achievable concentration factor defines the size and the costs of the subsequent thermal concentration step. As a reasonable consequence, the implementation of a high-pressure RO (HPRO) operation by appropriate membrane elements is desirable.

RO spiral wound elements (SWE) are usually able to withstand a maximum feed pressure up to 83 bar. To replace the energetically unfavourable thermal desalination processes sufficiently a HPRO element should be operational up to at least 120 bar. However, exceptional feed pressures lead to increased mechanical stresses on the components of the spiral wound element. To optimize the design parameters and establish constructive requirements, performance-limiting factors have to be redefined and evaluated. Taking this approach, the flux reduction as a result of membrane deformation and the influence of permeate-sided pressure drop induced by membrane-spacer interactions are examined in this study...

Flexible polymeric flters with low tortuosity produced in a roll to roll process

L.C. Sorvik*, M.-A. Raux, G. Osborg, H. Hemmen, Condalign AS, Norway

CondAlign has demonstrated a new method to produce membranes: The membranes are flexible polymer films with controlled dispersion of pores of near uniform size. The technology can also incorporate a layer of active particles exposed on the surface of the pores. Potential applications include microfiltration, catalysis and bioprocesses.

The membranes are produced by synthesizing an emulsion of a non-miscible liquid in a curable viscous polymer. The emulsion is spread out on a substrate and consequently introduced to an external electric field. The field coalesces the emulsion to droplets and aligns the liquid droplets, creating liquid pockets that stretches from top to bottom in the matrix. The polymer matrix is then cured and subsequent evaporation, washing or drying of the material creates the finished membrane.

The achievable diameter of the pores is proportional to the film thickness, the minimum diameter we have demonstrated so far is about 10 microns, but presumably this can be reduced further. The pores of the membrane can also be functionalized by adding specific molecules or particles to the emulsion. These will be positioned by the electric field at the interfaces of the two liquids in the emulsion and become exposed on the surface of the pores of the finished membrane.

The membranes produced by CondAlign’s technology have a near uniform pore size and distribution in the material. Furthermore...

The effect of membrane structure prepared from carboxymethyl cellulose and cellulose nanofibrils for filtration and biochromatographic separation

V. Kokol*, S. Gorgieva, V. Vivod, S. Vajnhandl, University of Maribor; T. Simčič, U.Černigoj, BIA Separations d.o.o., Slovenia

Water-stable and eco-friendly membranes were fabricated from carboxymethyl cellulose (CMC) acting as anionic adsorbent and cellulose nanofibrils (CNFs) as strengthening filler by solvent- and (unidirectional) freeze-casting processes, both supported with simultaneous citric acid (CA) mediated cross-linking. Spectroscopic and potentiometric titration techniques were applied to evaluate the efficacy of the cross-linking as well as to quantify the processing-dependant surface charge. In addition, the CMC/CNF assembling and membrane porosity were identified microscopically as the combinatorial effect of components ratio and the applied fabrication technique.

The membrane’s dye adsorption capacity and kinetic were evaluated for filtration performance at optimal pH (J. Polym Env 2019, 27/2, 318-332). The resulting, freeze-casted membranes demonstrate...


K2 - Keynote Lecture II

Day: 22 October 2019
Time: 14:45 - 16:00 h
Room 1A

Session Chair:
Prof. Eberhard Schmidt

Enhancing filter media performance during industrial gas filtration

Prof. Dr. Arunangshu Mukhopadhyay, National Institute of Technology, Jalandhar, India

The major challenge towards industrial gas filtration process is collection of finest particles by filter media with least energy and also achieving longest possible life of filter media. This leads to quite significant technological intervention for designing appropriate filter media as well as filtration system. For enhancing filter media performance, understanding filter material behaviour under different operating parameters (e.g., level of filtration velocity, cleaning intensity and mode of cleaning, temperature and humidity) is very important. In the development of industrial filter media, a common approach is enhancing surface filtration. Filter media are mostly nonwoven with membrane/coating, or it could be woven structure in case of glass with membrane for high temperature filtration. Understanding filter media behaviour in real situation is very complex and cannot be accomplished using present system of characterization techniques. The filter media (differing in composition) possessing same initial physical, mechanical and filtration properties can behave differently during industrial filtration situation. Selection of suitable operating parameters should also be governed by filter media characteristics besides the application requirement. Study reflects that pulse pressure parameters in a pulse jet fabric filtration system should be set in accordance with fibre fineness in the media, maintaining a balance between emissions and operational pressure drop across the media. Further higher pulse pressure is better in the case of higher media dust loading.

Every attempt must to be made to minimize aerodynamic and mechanical damage, chemical degradation, temperature degradation, thermal shrinkage, particle clogging and blinding, condensation and sublimation during filtration. Since even small membrane damages will allow dust penetration through the fabric, one of the major challenges is the development of strong membrane without affecting permeability characteristics. Needless to say media performance at high heat is most critical and challenging. In case of hot gas filtration, quite significant decrease in breaking strength with time is quite common thus affecting life of the filter bag. The decrease in the breaking strength of the filter fabric is a result of fiber degradation at high temperature and flexing of filter media during pulse cleaning. The filter materials differing in composition possessing same initial strength can have different level of strength after exposing to hot gas filtration. Stiffer material structure besides the right choice of raw material is therefore important for high temperature filtration. The same will be highlighted following a case study...


F2 - Progress in Wire Mesh Development

Day: 22 October 2019
Time: 14:45 - 16:00 h
Room 4B

Session Chair:
Dr. Graham Rideal

New developments in woven wire filtration media: 3D high perfomance filter cloth; Woven wire mesh combinations in solid-liquid separation

F. Edelmeier*, F. Meyer, Haver & Boecker OHG, Germany

Previous filter cloths with small pore sizes lead to reduced flow rates and significant pressure loss in the production process. The cloth structure of a newly developed three-dimensional weave increases the number of pores and thus the open surface over the same area. For a given pore size, the flow rate is more than doubled compared to conventional Dutch Weaves. The pore size within a batch can be calibrated as desired from 5 µm to 40 µm.

Conventional woven wire filter cloths can cause turbulences that affect the filtration process at high flow rates. Turbulences with the 3D-filter cloth is effectively avoided.

Its pore size can be calculated precisely in advance and adapted to the respective requirements. The mathematical formulae for determining permeability were developed in cooperation with the University of Stuttgart within the scope of AVIF projects A224 and A251, and experimentally validated by glass bead tests and air flow-through measurements.

These predictable pore sizes can achieve extremely high cut-points and dimensional stability. The depth structure of the new woven wire filter cloth facilitates high separation efficiency without rapid blinding. This leads to longer filtration processes between cleaning intervals and longer service life for greater production reliability.

The 3D metal filter cloth is woven from standard diameter wires. Moreover, it is possible to weave special materials such as Alloy 310 S, Hastelloy C 22, Inconel 600 or titanium even in the small pore range. Thus, for the first time, filter cloth with pore sizes below 40 µm can be manufactured in corrosion- and temperature-resistant alloys...


  • Twice the flow for a given pore size
  • Excellent cut-point and stability
  • Corrosion and temperature resistant special alloys
  • Optimum dirt holding and purging properties
  • Different pore sizes in one batch from 5 µm for 40 µm

The effect of different gradient structures on the load-dependent fractional separation efficiency and its dirt hold capacity have been subject of design considerations in single and multi-layered woven wire mesh combinations in solid-liquid and solid-gaseous separation.

In cooperation with the Institute of Mechanical Process Engineering in Stuttgart (IMVT) different gradient structures of wire mesh filtration media were investigated as to their influence on the load-dependent fractional separation efficiency (FAG) as well as their dirt holding capacity. In addition, different offline measurement techniques and particle systems and their influence on the result of the FAG and the dirt hold capacity were investigated and evaluated.

Square mesh fabric as well as filter fabric in twilled and plain weave and their combinations in sintered and unsintered condition have been described. It was confirmed that.....

Energy reducing polymeric filtration mesh

J. Ferrer, J. Kirk*, J. Kidwell,, SWM International, USA

In many liquid filtration systems a reduction in cross flow resistance will lead to a reduction in the energy consumption of that system.

The ASD (Alternating Strand Design) technology by SWM is an innovative polymeric mesh that has been developed with this energy reduction in mind. By alternating the diameter of every other strand of the mesh, ASD technology can deliver up to 15% reduction in pressure drop compared to conventional polymeric mesh.

Simply lowering strand count can reduce the energy consumption of a conventional filtration mesh; however, the number of Strand Intersection Points (SIP) per unit area of the mesh is reduced. This compromises the dimensional stability of the filtration mesh. Reduction in dimensional stability can cause material handling difficulties during the manufacturing of the filter as well as performance issues during operation. Instead of reducing the strand count and SIP, ASD technology maintains strand count and SIP but reduces the diameter of every alternate strand. This results in a filtration mesh structure that consumes less cross-flow energy yet maintains the dimensional stability.

Designed & developed using CAD, CFD and 3D printing

Initial design work was done using 3D CAD and Computational Fluid Dynamic (CFD) modeling to determine the optimum size and shape of the large and small strands. The size of the smaller strand was optimized with CFD to offer maximum energy reduction yet still maintain dimensional integrity. Once the final design had been established, a 4x6 inch 3D printed prototype of the mesh was produced using energy-cure jet printing technology. The jet printing method was chosen due to the fine structure of the mesh geometry.

The prototype mesh was then tested in a benchtop cross-flow tester to evaluate the improvement in pressure drop (energy consumption) compared to the conventional mesh. We were able to demonstrate a 15% improvement (decrease) in pressure drop for the ASD technology...

Multipore™: The state-of-the-art wire mesh

S. Vandendijk*, Parker Hannifin Purolator, Belgium

With the applications in gas filtration, lubrication applications and industrial process filtration, the wire mesh is treated as a versatile product with wide range of allowable specifications. Usually, the wire mesh filters are characterised by the mesh material, pore count and wire diameter for a given application. Multipore™ media from Purolator-Parker has a Dutch weave wire arrangement

where the opening between the successive chute wires is smaller than the opening of the “filtration triangle”. Figure 1 shows the details of the wire arrangement of Multipore™.

The major accomplishments of Multipore™ can be summarized as following:

  1. Higher porosity of the mesh ensures a longer life time
  2. Higher shearing to break gels offers better quality
  3. Until 2017, the filtration grade was between 15-90 μm, which is now improved to 7-100 μm
  4. Sharp cut-off efficiency


G2 - Cabin Air Filters

Day: 22 October 2019
Time: 14:45 - 16:00 h
Room 4A

Session Chair:
Dr. Martin Lehmann

Cabin air quality and energy savings in electric vehicles by using a smart filtration system

M. Lesage*, D. Chalet, Ecole Centrale de Nantes; L. del Fabbro, E. Le Nain, Renault SAS, J. Migaud*, MANN+HUMMEL, France; D. Ebnet, MANN+HUMMEL GmbH, Germany

Heating and cooling of the cabin air drains energy especially for electric vehicles. This energy comes from the battery, and, as a consequence, cannot be used for car propulsion. In addition, requirements are more and more important concerning the cabin air quality. The objective is to protect the passengers from ultrafine particles or harmful gases by using advanced filtration technologies (HEPA filter, adsorption). Compared to houses or buildings, car passengers are confined in only a few cubic meters volume. Cabin air quality depends on fresh and recirculated air flows. As a consequence, filtration solutions are developed and implemented in the HVAC (Heating, Ventilation and Air Conditioning) system.

From the outside to the cabin, the system studied in this paper is composed of three individually adjustable elements: ambient filter, HEPA filter and cabin filter. These different stages are activated depending on the air pollution level of the environment and driving conditions (traffic jam, tunnel, city, outback…) with possibility to minimize the energy consumption for heating or cooling. In addition, different sensors (particles, gases, temperature…) monitoring the indoor and outdoor air quality can be used in order to optimize the filtration system regulation. In reality, for typical driving conditions, ambient air enters by infiltration (depending on the vehicle speed), allowing particles, NOx, SOx, and NHx to enter into the cabin but not through the HVAC system (and as consequence not through the filters). The infiltration level depends on the cabin pressure and the vehicle speed.

In this article, a compromise was found between fresh air and recirculation mode for every driving condition, number of passengers, history, outside air pollution level, energy consumption level and cabin thermal management system...

Test of cabin filters

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

Cabin filters are used for comfort purposes but also as safety equipment. Especially the use of gas filters in protection cabins requires knowledge about the cleaning efficiency at the expected ambient air conditions. With a series of experimentally determined test results the ILK Dresden shows the influence of air temperature, humidity, air velocity and test gas concentration on the gas separation.

By upgrading a test rig designed according to ISO 11155 it became possible to test filters and adsorptive materials also at low flowrates, high humidity and with toxic gases like SO2, NH3 and H2S. The ILK proposes a test routine to qualify cabin filters, which should be tested in a comparable way to standards for mask filters of personal protection equipment. Essential parts of actual standards are included or adapted in the new test routine. So a basis was made to create a new official test standard...

Maximising comfort and minimising pollutant exposure in the vehicle cabin using the ventilation system

T. Cardy*, N. Molden, Business Development Manager, Emissions Analytics Ltd, UK

Vehicle thermal management and air conditioning systems play an important role in protecting the driver and passengers from pollution ingress into the vehicle, and from the build-up of carbon dioxide in the cabin. With air pollution in excess of legal limits and World Health Organisation guidelines in many areas across Europe, drivers may be particularly susceptible.

Emissions Analytics has worked in collaboration with National Air Quality Testing Services (NAQTS) and the University of California Riverside to develop a new in-cabin air quality test programme that measures the rate of particle number (down to 15nm in size) ingress into the cabin under different air conditioning and air recirculation modes. In those same scenarios, it also measures the build-up of carbon dioxide and compares it to levels associated with cognitive impairment. Finally, it considers the air replacement rates and therefore the speed with which the air conditioning system can clean up pollutant concentrations in the cabin.

Through this testing, Emissions Analytics will make comparative EQUA Index ratings in order assess the effectiveness of the filtration design components on the vehicle and to compare between vehicles. In this way, it will incentivise the development of the most effective systems and allow optimal choices to be made on the trade-off between pollution ingress and cabin stuffiness.

Furthermore, data from a new EQUA Index programme on in-cabin air quality will be presented, covering the rate of particle infiltration from a range of modern cars, and the propensity of carbon dioxide concentrations to rise when the air recirculation mode is activated.


L2 - Particle, Slurry and Cake Characterization

Day: 22 October 2019
Time: 14:45 - 16:00 h
Room 1B

Session Chair:
Prof. Dietmar Lerche

The effect of normal load on the shear yield stress of suspensions

A.D. Stickland*, E. Höfgen, University of Melbourne, Australia

Understanding the rheological behaviour of suspensions is crucial for the design and operation of processes involving mineral slurries and wastewater treatment sludges, and for the formulation and product performance of coatings and ceramics, for example. The solid particles in concentrated suspensions form continuous particulate networks that can withstand an applied force and behave as a soft elastic solid. Suspensions flow or collapse if the force exceeds the network strength at a given volume fraction f. The yield point in shear is often naïvely described by the shear yield stress, although this has been shown to vary with applied rate. In solid-liquid separation processes, a compressional load is applied to just the solid phase of the suspension. This is the applied pressure in filtration or the buoyant weight of the particles in sedimentation. If the load exceeds the compressive yield stress, the solid phase consolidates or densifies, that is, it forms a filter cake or a sediment. Consolidation continues until the network strength is equal to the applied load....

.... We have developed two new techniques and demonstrate that, upon confinement of the particles and application of a normal load...

Monitoring technique for mechanical expression using electrokinetic response caused by liquid flow through filter cake

M. Iwata*, K. Shimoizu, T. Iwasaki, Osaka Prefecture University, Japan; M.S. Jami, International Islamic University Malaysia, Malaysia

In expression operation using filter-press of compression type, slurry material is filtered by pressure provided by a pump. When the chamber is filled with filter cake, the cake is expressed by the movement of the flexible diaphragm. Exact identification of the time that the chamber is filled with the cake is essential for effective operation of the press. The electrokinetic response provides us with some information on the status of the filter chamber. In this work, we have measured the time course of electric potential difference (EPD) between the retaining walls during the whole process of expression to elucidate the electrokinetic aspects of mechanical dewatering. The experimental apparatus used in this study consists essentially of a piston press with a cylinder and a piston of 6 cm or 10 cm in diameter. Filter media are placed at the cylinder bottom and the very end of the piston. EPD between the filter media was monitored during the experiment. The absolute value of EPD increases with the progress of the filtration period, followed by the decrease during the consolidation period. It was observed that...

The influence of bimodal particle systems on filter cake structures using micro tomography

E. Löwer*, F. Pfaff, T. Leißner, U. A. Peuker, Technical University Bergakademie Freiberg, Germany

The use of X-ray microscopy (XRM) for characterizing particle systems offers more and more applications in particle technology: With raising voxel resolution the size and shape of particles in bulk powders e.g. the analysis of filter cake structures allows more information about micro processes during filtrbimation and de-liquoring, supporting an enhanced understanding of industrial process characteristics. Tomography measurements provide information about the build-up of porous systems, quantified by using key parameters and distribution functions.

The solid-separation of wide spread particle properties make the prediction of filtration processes difficult. Besides broadly distributed properties like size, shape and wetting behavior the location, the dispersion range and the shape of the distribution has to be taken into account. Multimodal distributed particle properties described in literature originate from a change in bulk structure at which the fine fraction starts to dominate the force transmission and the interparticular contact number. Investigating the change and its influence on cake filtration, the use of X-ray microscopy makes an insight into the substructure on micro-level basis possible.

For tomography experiments, filter cakes according to VDI 2762 are built with respect to the measurement volume. Particle systems of self-similar fractions (crushed Al2O3) between 20 and 200 µm are mixed to bimodal distributions. The volume fractions of fines between 20 and 60 % are compared with the monomodal fine and coarse fractions with regard to global and local porosity, permeability, geometric tortuosity and coordination number...


M2 - Micro and Ultra Filtration

Day: 22 October 2019
Time: 14:45 - 16:00 h
Room 2

Session Chair:
Dr. Christine Sun

Interaction between polysaccharide and protein on membrane fouling caused by microbial metabolite

N. Katagiri*, R. Matsuyama, E. Iritani, Nagoya University, Japan

In recent years, microfiltration is used in wastewater and drinking water treatments, and food and pharmaceutical industries. However, it is well known that one of the principal limitations to the widespread application of the microfiltration process is membrane fouling, which results in a dramatic increase in the filtration resistance accompanying with the progress of filtration, thereby leading to a severe flux decline. Such membrane fouling may be brought about by the clogging of membrane pores and/or the particle deposition on the membrane surface referred to as the filter cake. In the process of using microorganisms, the feed solution is a complex mixture comprising bacterial flocks and microbial metabolite. Therefore, it is essential to clarify the mechanism of flux decline behaviors in microfiltration of microorganism and its metabolite. The key objective of this study is to examine the effect of polysaccharide-protein interaction on membrane fouling caused by microbial metabolite since the microbial metabolite is composed mainly of polysaccharides and proteins...

Effect of aeration on hollow fiber microfiltration characteristics of activated sludge

K. Kawasaki*, H. Hosokawa, A. Minakuchi, Ehime University, Japan

We made constant pressure filtration (Fig.1) of the excess activated sludge using the microfiltration hollow fiber made of polyethylene with pore size 0.1 μm with/without aeration condition under various suction pressure(8.0 or 61.3 kPa).

We used three samples as described below. (1) "Activated sludge (AS)", which is the excess activated sludge from the municipal wastewater treatment plant in Matsuyama, Japan, settled for 18 h in the refrigerator (5 oC). (2) "Centrifugal settling supernatant (CSS)", which is the supernatant of "Activated sludge" by the centrifugal settling (3000 rpm, 1600 g, 10 min). (3) "Glass fiber filtrate (GFF)", which is the filtrate of "Centrifugal settling supernatant" with glass fiber filter (nominal pore size: 0.6 μm).

Thereby, we could widely examine the effect of various kinds of solids in the activated sludge on the filtration characteristics of this hollow fiber microfiltration...

...The influence of the aeration operation on the constant pressure filtration characteristics of activated sludge can be quantitatively shown....

Influence of oil droplet size distribution on the fouling mechanisms of UF/MF membranes during filtration of oil nano-emulsions

H. Idrees*, M. Abo Zohri, I. ElSherbiny, S. Panglisch, University Duisburg-Essen (UDE), Germany

Every day, a minimum of 40 million m³ of hazardous oily wastewater, known as “Produced Water”, are ‎discharged from oil and gas industries into the environment. Therefore, efficient and sustainable treatment methods have become a necessity. Membrane filtration is considered as ‎promising separation technology in this field‎. Nevertheless, detailed studies ‎interpreting the fouling mechanisms are limited. For instance, the influence of oil droplet size on the membrane fouling mechanisms is not completely understood. In this study, the separation efficiency and fouling mechanisms of polyethersulfone and ceramic membranes exhibiting different average pore size in range of UF and MF during purifying of synthetic oily wastewater are investigated.

This study aims at investigating the influence of oil droplet size distribution on the filterability of oily nano-‎‎emulsions, in addition to determining type and chronological sequence of the expected fouling mechanisms.‎ This work is a part of a ‎research project focusing on evaluating and enhancing the feasibility of UF membranes as a polishing step in the treatment of produced water...


F3 - Advanced Filter Media Developments and Manufacturing Methods

Day: 22 October 2019
Time: 16:45 - 18:00 h
Room 2

Session Chair:
Dr. Harald Anlauf

High speed laser drilling of precise micro and nano holes in metallic surface filters

T. Barthels*, H. Westergerling, M. Reininghaus, Fraunhofer Institute for Laser Technology ILT, Germany

In the field of micro and nano structuring, ultrashort pulse (USP) laser material processing with a multibeam approach is attracting increasing attention due to its ability to generate periodic patterns with high throughput (up to 12.000 holes/sec). A wide range of applications exists for the generated structures, e.g. functional structures for the automotive industry, consumer electronics but also for filtration technology. USP laser with a pulse duration of several 100 femtoseconds are already commercially available today and are suitable for the generation of precise structures in various metals in the micrometer and sub-micrometer range. The multibeamscanner (MBS) developed at the Fraunhofer ILT enables laser processing with more than 200 beams in parallel and a precision < 1 µm. The MBS offers the potential to provide filter membranes of stainless steel foils with sub-micrometer-sized holes over a large area. The production technology is suitable for manufacturing regenerative microfilters for industrial applications in the fields of biotechnology, pharmacy and medical technology.

Application for high precision surface filter inserts

For more than ten years, the Fraunhofer ILT has been active in the field of high-precision structuring of metal foils using USP laser systems. Metal foils with thicknesses from 5 µm to 100 µm are commercially available with holes sizes down to the lower single-digit micrometer exit diameter.

Microplastics and pathogens: The surface filter cartridges are currently being developed to filter microplastic particles of >10 µm out of wastewater. Microplastics are the smallest plastic particles with a diameter of <5 mm [1], which are either deliberately used in a wide variety of products or are caused by natural abrasion and erosion. Synthetic micropolymer particles, which are referred to as primary microplastics, serve in many hygiene products as peeling particles, binders or fillers and enter after the use of the product the water cycle and thus in our food chain [2]. In addition to the social interest of water pollution by microplastics, the pollution of water by bacteria and multi-resistant pathogens is becoming more and more important for our society [3]. Using suitable USP laser and the patented multibeamscanner, the Fraunhofer ILT develops a technology for drilling holes with sub-micrometer size in stainless steel foils at a pitch distance of a few micrometers. The surface filter inserts designed for the filtration of microplastics can also be used to filter pathogens by further reducing the hole diameter...

Augmented filter media development by virtual prototype optimization

T. Gose*, A. Kilian, H. Banzhaf, F. Keller, R. Bernewitz , MANN+HUMMEL GmbH, Germany

In transportation, the future of drivetrains is one of the prevailing topics these days1. As the evolution of internal combustion engine technology has been requiring continuous optimization of oil filtration technology and oil filter media, bridging technologies like hybrid electric vehicles (HEV) and modern drivetrain concepts will generate new, equal challenging, requirements. While development cycles are getting shorter and time-to-market is a key, augmenting conventional filter media development with sophisticated computational methods is of great potential to address current and future needs.

Over the past decade, computer simulation of the loading kinetics at the microscale level has evolved into a powerful tool for the development of future generations of filter media2. This becomes increasingly essential to achieve the desired filtration performance, to improve energy consumption and to detect cost savings. The valuable insight offered by virtual filter media development provides details of the filter media design and the filtration performance and enables the development of innovative virtual filter media prototypes.

In this presentation an overview of present demands and future drivetrain concept requirements’ towards oil filtration media is given. At hand of a recent use case for a synthetic filter media, we demonstrate the state of the art procedure of virtual filter media development at MANN+HUMMEL. Starting from a reference material structure based on micro-computed tomography, we show the derivation and validation of a virtual fiber model, which in turn is computationally investigated, optimized and resulted in a noticeably increased filtration performance. Hidden potentials are revealed and we are able to identify optimized virtual filter media design concepts for specific objectives, such as filter lifetime enhancements or cost savings. Finally, we will discuss the transfer of virtual prototypes to material samples and eventually the industrialization into filtration products.

Exentis Group AG: Industrialized Additive Manufacturing

S. Vasic*, Exentis Group AG, Germany

Exentis Group AG (Exentis) 3D screen printing technology is a novel approach to 3D printing. The technology is protected by 13 patent and patent application families (Exentis 3D Mass Customization®). It is the only 3D printing technology capable of mass producing 3D printed parts. In addition, based on the same production units (the Exentis terminology for the self-developed 3D printers), it offers a choice between any number (over one hundred) of materials. Ultimately, all classes of materials (ceramics, polymers and metals) that are available in powder form can be printed. These are processed into pastes with additives to produce ultra-fine geometries, and multi-layer systems with different materials, as well as several materials in each level can be realized in one system. The method currently has its limits in the size of individual components which cannot exceed a side length of 400 mm and a height of 200 mm.

The process itself is a cold-pressure process, which thus works energy and environmentally friendly in the production of, for instance, several thousand components per print job. With the inline versions of the production units, printing speeds of approx. 5 seconds per printing layer can be achieved, significantly faster than for established 3D printing processes. For example, in the case of ceramic pressure sensors with a height of 10 mm and a print layer height of 50 micrometers, i.e. 200 layers, around 1,600 components can be produced simultaneously in 15 minutes.

The necessary densification of the components by subsequent sintering takes place via the combination of several 10,000 components in a sintering batch and therefore leads to the energy-efficient one-time use of the furnace per production batch.

Exentis is also the only 3D printing process to offer production technology suitable for cleanroom environment. Today, with bioprinting, living cells are already being printed into tissue and novel forms of active substance administration are being produced, under GMP guidelines.

Compared with other classic manufacturing processes, such as hot isostatic pressing, the technology allows any shape as well as smaller dimensions, not currently available with today's tools...


G3 - Gas and Particle Separation

Day: 22 October 2019
Time: 16:45 - 18:00 h
Room 4A

Session Chair:
Prof. Gerhard Kasper

Simultaneous dust and noxious gas separation in an entrained-flow adsorber on surface filters

F. Prill, S. Schiller, H.-J. Schmid*, University of Paderborn; M. König, I. Hartmann, DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH, Germany

In biomass combustion plants (Pth < 5 MW), hot, dust-laden flue gases are generated, which frequently also include gaseous pollutants such as, SO2, NOX and HCl. The steady updating of the pollutant limit values requires the development of a more efficient flue gas cleaning technology. Methods available on the market for the flue gas purification of all components to be considered are not yet economically viable for biomass combustion plants < 5 MWth. Within the research project “SCRCOAT”, which is financially supported by the Federal Ministry of Economics and Technology (BMWi), new ways of designing gas purification systems for biomass combustion plants with a thermal output of < 5 MW have been developed.

For this reason, an existing test rig at the Paderborn University was extended. A catalytically coated fabric material (filter blank diameter = 100 mm) enables the combination of dust filtration with fabric filters and selective catalytic reduction (SCR) of NOX. The dust is deposited on the outer surface of the filter element and then the nitrogen oxide reduction on the catalytically coated inside. First, the deposition of noxious gases was investigated. This means that the pellet boiler (Pth = 15 kW) remained off and thus the fine dust was not considered. The aim was to investigate the dependence of the deposition of noxious gases (NOX, HCl, SO2) on the precise dosage of these gases and on the precoat material used in the laboratory test rig. Due to the defined addition of the abovementioned noxious gases, various operating states could be simulated...

A new PM2.5 assessment for a gas-liquid cross-flow array system as dust separator

W. Wei*, H. Yu, J. Zhu, Sichuan University, China; T. Laminger, W. Höflinger, Technical University of Vienna, Austria

It is considered to be a valid method for using the waste water of an industrial plant to control the air pollution of the exhaust gas, which is one of the main sources of atmospheric particulate matter. A GLCA (Gas-Liquid Cross-flow Array) wet scrubber system, already described in detail by Zhu J. et al [1], is proposed to be a dust separator to remove particles in the exhaust gas. A continuous and regular liquid column array is formed under the force of gravity with a holed distributor, by which the particles will be captured when the dusty gas flows through the column array.

Tests were executed on a lab scale test rig for different operation and apparatus parameters and the fractional separation efficiency and the pressure drop were measured. Using a simplified PM2.5 definition [2], a method will be presented how the minimum number of water column unit rows in series n could be found, with the aim to reach a certain PM2.5 limit value. Further a quality factor is used to optimize other parameters, e.g. the gas through-put velocity...

Influence of the deliquescence and efflorescence of hygroscopic salt particles on the performance of surface filters

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

The progress of pressure loss during the filtration phase as well as the residual pressure loss after regeneration are characteristics of the performance of surface filters for dust separation. These characteristics are significantly influenced by both the specific cake resistance and the adhesive forces of dust particle contacts. The specific cake resistance decreases, besides other factors, with increasing pore sizes. The mechanical strength of the dust cake in turn depends on the adhesive forces of particle contacts in the dust cake. For the removal of the dust cake from the filter medium an increased mechanical strength is desirable, since the amount of energy needed for regeneration can be reduced. In terms of process technology, these characteristics can be influenced by raw gas conditioning, for example by changing the particle characteristics in the dust cake.

The metered addition of a fraction of hygroscopic salt particles provides a possibility for influencing the performance of surface filters for dust separation. By temporary modification of the gas humidity deliquescence and efflorescence of the added salt particles will be induced to subsequently change the adhesive forces of particle contacts as well as the structure of the dust cake formed on the filter medium. This changes the performance of the filter.

The present contribution presents investigations into the influence of the change in the performance of test filters by inducing deliquescence and efflorescence of a fraction of salt particles in a dust cake. These investigations were carried out on an adapted filter test apparatus according to VDI 3926-1. The conditioning concept as well as the operating behavior of test filters, such as the pressure loss curves and the regeneration results are presented.


G4 - Mist and Droplet Separation

Day: 22 October 2019
Time: 16:45 - 18:00 h
Room 4B

Session Chair:
Prof. Eberhard Schmidt

Characterization of performance relevant media properties in oil mist filtration

T. Penner*, J. Meyer, A. Dittler, Karlsruhe Institute of Technology; W. Heikamp, BinNova Microfiltration GmbH, Germany

Coalescence filters are commonly used to separate oil droplets from air streams and nonwoven glass fiber filter media are used for applications where high efficiencies are required, for instance for compressed air preparation. The relevant mechanisms in oil mist filtration and their impact on operational behavior of the filters have received increasing attention in research over the last few years and are qualitatively well understood by now. However, the relationship between structural properties of the filter media and the operating performance of the filters is relatively unknown and therefore filter media are commonly chosen based on empirical values depending on the application. In this work filtration relevant media properties were identified and their qualitative impact on operating performance was tested.

To find correlations between media properties and operating performance of the filters, various custom made nonwoven glass fiber filter media were characterized using several methods, such as x-ray microtomography and scanning electron microscopy. These methods were evaluated regarding their suitability in identifying structural and surface properties. Based on theoretical approaches the qualitative impact of these properties on oil deposition and transport mechanisms in the media and therefore on the operation performance was estimated. Filtration tests were carried out to evaluate these approaches by measuring filter efficiencies and differential pressure and their respective changes during filtration.

Recent data obtained in the experiments will be presented, evaluated and discussed...

Reducing pressure drop of coalescence filtration media by patterned modification of wettability

M. Wittmar*, W. Mölter-Siemens, K. Varzandeh, C. Asbach, Institute for Energy and Environmental Technology e.V. (IUTA); L. Tsarkova, T. Bahners, B. Gebert, DTNW - Deutsches Textilforschungszentrum Nord-West gGmbH, Germany

Coalescence filtration is a widely used technique in industry to remove oil from compressed air and to achieve suitable air qualities for production processes in order to protect devices and the workforce. Typical filters are constructed of nonwoven fibers and represent a heterogeneous media with complex permeability and capillary properties, which are defined by the fiber sizes and media density, surface tensions, oil viscosity, and droplet dimensions. One of the important parameters among the filter efficiency parameters is the saturation of the filter medium. The resulting pressure drop increases significantly the energy costs of the process. According to the channel-jump model the formation of an oil film in the filter media has a major influence on the pressure drop. In case of an oleophilic filter medium, the oil film is formed on the downstream side of the filter and is directly coupled to the drainage efficiency. The presented work aims at reducing the pressure drop and directing the oil drainage by introducing...

New physical principle of dilution system for crankcase ventilation filter testing

S. Schütz*, M. Schmidt, PALAS GmbH, Germany

The dilution of large droplets is particularly important when measuring highly concentrated droplet aerosols. Since large droplets are difficult to dilute, standard systems only work up to a size of 1 - 2 μm

Problem of existing dilution systems:

  • Large droplets (above 3-5 µm) are destroyed
  • Change of the dilution ration in regards to the particle size

According to this Problem it is very difficult to get a good correlation between the optical measured mass and the gravimetrical evaluated mass with a droplet aerosol, e.g. in the crankcase ventilation filter testing.

The target for the development of the new dilution system LDD was to dilute large droplets with practically no losses to get a better correlation between the optical measurement and the gravimetrical result. To prevents condensation, the model variant LDD 100 H can be heated up to 120 °C.

The newly developed dilution system LDD 100 H (dilution factor 100) is the first system to dilute almost loss-free large droplets up to 10 μm. The good dilution ratio was proven with monodisperse DEHS oil droplets of different sizes. The results of 5 µm & 7 µm are...


L3 - Cake Filtration - Influences on the Cake Structure

Day: 22 October 2019
Time: 16:45 - 18:00 h
Room 1A

Session Chair:
Prof. Urs Peuker

Investigation of coating effect on filter cake characteristics

M. Brockmann*, T. Leißner, U. A. Peuker, Technical University Bergakademie Freiberg, Germany

In this work, we focused on the filtration of two particulate materials different in particle shape to investigate the effect of particle shape and coating on the filter cake characteristics. To study the shape and coating effect, we choose Al2O3 and wollastonite powder in a similar particle size distribution range. The Al2O3 powder represents the spherical particles used in this research, and for the case of needle-like particles, we applied Wollastonite. To hydrophobize the particle surface, we implemented Silane Octeo for coating.

As the filtration starts, an observable difference can be noticed in the filter cake building time. As Ethanol increases, the cake building time decreases. Interestingly, the cake building time remains as a function of the Ethanol proportion in the solution.
Noticeably, with an increase in the amount of ethanol volume, we get a significant decrease in porosity for both particle shapes, for the coated Al2O3 and coated Wollastonite. The decreased amount of the porosity is in strong relation to the change of the surface tension and wetting properties. As the ethanol increases...

Understanding the role of cake structure in the filtration of needle-like crystals in the pharmaceutical industry

G. Perini*, C. Avendaño, T. Vetter, University of Manchester; W. Hicks, A.R. Parsons, AstraZeneca, UK

The filtration time in the pharmaceutical industry can be critical for the feasibility of a process [1].In this field, filtration is used to recover crystals of active pharmaceutical ingredients or intermediates resulting from purification processes [2]. The time required by this step is heavily influenced by the size and the shape of the crystals being filtered, which is a result of the nature of the compound and the way the particles are generated [3,4]. Crystals often have non-equant morphologies and even though there is considerable knowledge on how to predict and control the final shape and size they will have, there is no direct way to forecast how they will filter. The size and shape of the particles are important for filterability because they influence the way particles pack, therefore the internal structure of the filter cake. This, in the end, determines the cake resistance, and hence the filtration time.

Being able to predict how populations of particles with different sizes and shapes will behave during filtration would enable us to find the optimal crystallization conditions that require the minimum combined processing time. It would improve and speed up process development allowing new drugs to get to the market sooner...

Evaluation of process strategies to homogenize the lautering filter cake structure and enhance wort production

P. M. Bandelt Riess*, M. Kuhn, H. Briesen, P. Först, Technical University of Munich, Germany

Lautering is a traditional, widely used solid-liquid separation method in the brewing process and it is often considered as the bottleneck of the brewhouse. After obtaining the wort, the remaining spent grain filter cake exhibits high compressibility and a very inhomogeneous, layered structure. These layers show similar permeabilities, with the exception of the top one, the Oberteig, which can become an obstacle for the wort flow and a delay in production time. Therefore, measures to accelerate this operation are desired. It is proposed that homogenizing the filter cake structure accelerates the process.

To assess the hypothesis, different process engineering strategies were tested and evaluated in a laboratory-scale lauter tun: increase of the solids concentration in the suspension, flocculation of the fine particle fraction, and usage of packed beds as filter aids. The results were compared to a standard lautering procedure based on filtration duration, filtrate turbidity, and extract content...

....findings might directly help breweries to improve their lautering processes, optimize production in the brewhouse, and foster further research on the topic.


L4 - Wet Particle Fractionation

Day: 22 October 2019
Time: 16:45 - 18:00 h
Room 1B

Session Chair:
Prof. Hermann Nirschl

Centrifugal classification: In-situ method to determine separation efficiency by UV-VIS spectroscopy

M. Winkler*, H. Nirschl, Karlsruhe Institute of Technology (KIT), Germany

Classification is an established process in solids processing technology to divide particulate products into defined fractions based on their size. However, complex particle systems with strict specifications for product-relevant properties often require a different approach. Thus, multidimensional fractionation is needed in which both geometric (particle size and shape) and material (density, interfacial properties) separation characteristics are taken into account.

Previous studies focused on the subordinate step of classification in semi-continuous tubular bowl centrifuges, which enable the separation of ultrafine particles due to high rotation speeds at high throughput rates. Further experimental studies expand the focus from well researched single substance to multi-component systems. Under constant operating conditions, differences in sedimentation velocity determine the percentage of fine and coarse material in the product stream. With enormous centrifugal forces affecting each particle in a collective, the process enables successful fractionation even with small differences in sedimentation velocity, which in turn is influenced by particle size, solid density and density of the dispersion medium. However, the disadvantage of sediment buildup in the rotor persists for any given fractionation step. Therefore, in order to maintain practical viability an online measurement technique is required which aims to counteract the loss of separation efficiency due to sediment buildup by adjusting the rotor speed. The difficulty lies in the acquisition of the above-mentioned, distributed separation criteria in complex multicomponent systems. Furthermore, data processing must allow a clear assessment of the separation efficiency during centrifugation. In light of this, the presented work centers on the development and implementation of said measurement methodology following the multidimensional fractionation using a powerful tubular bowl centrifuge...

Automation of particle classification in a tubular centrifuge based on a dynamic short-cut process model

T. Sinn*, M. Gleiß, H. Nirschl, Karlsruhe Institute of Technology (KIT), Germany

The process industry is currently facing multiple challenges. The incessantly growing request for sustainability increases the demand in both resource-efficient processes and optimal exploitation of the potential production plants offer. Conventional practices in plant operation usually do not satisfy this demand, following procedures based on previous experience. These are not flexible and detailed enough to sufficiently cover changing process behavior and thus, do not yet lead to operation at the efficiency optimum. At the same time, the focus also lies on product quality. Specific properties are supposed to be achieved within narrow tolerances. This reinforces the need for accurate operational settings.

Regarding the domain of centrifugation, these challenges are equally relevant. Power and material consumption are to be reduced while meeting the demanded product properties by appropriate operation.

In the case of tubular centrifuges, an additional challenge arises with the inevitably semi-continuous mode of operation. During the separation process, material separated from the injected slurry accumulates at the inner surface and builds up a sediment. With increasing sediment height, separation efficiency generally decreases whilst operational settings remain unaltered. The properties of the product – the particle size distribution at the outlet, in this case – permanently change, accordingly. It is thus necessary to develop a sensible control strategy, which is able to cope with the complex and time-dependent behavior of the apparatus.

This work shows a new approach to controlling a tubular centrifuge based on a short-cut process model in order to achieve a desired particle classification throughout the entire time span of an operating cycle...

Fractionating of finest particles using the crossflow filtration

P. Lösch*, V. Puderbach, K. Nikolaus, S. Antonyuk, Technische Universität Kaiserslautern, Germany

Fine particles dispersed in a liquid phase with highly specific physical properties are gaining in importance. These suspension are often intermediates for the production of coatings, structured reinforced plastic or for printed electronics.

Production processes like precipitation or crystallization often generate particles with broad particle size distributions. In known separation processes, such as sedimentation, filtration or centrifugation, the particles are either classified according to a certain grain size or sorted by a physical characteristic. However, in many applications in which finely dispersed multicomponent mixtures of particles with sizes < 10 μm with different properties are to be separated in industrially relevant quantities, the usage of a single separating feature is often no longer sufficient. In this research project, a novel cross-sectional superficial electric field filtration technique is being developed, which is a promising method for the highly specific separation of micro- and sub-micron suspensions. The method not only allows fractionation with regard to the particle size, but also the particle shape, the chemical composition and the physical properties of the individual particles.

In this study, the test plant is developed and constructed. Based on CFD-simulations, the flow channels and the size of the filter area were designed. The hydrodynamic forces on the particles in the laminar boundary layer are investigated. The possibility for the use as classification process in the crossflow will be...


F4 - Quality Control and Pore Size Analysis of Filter Media

Day: 23 October 2019
Time: 09:00 - 10:15 h
Room 4A

Session Chair:
Prof. Antti Häkkinen

Optical quality control of filter media: MIDA X makes hidden defects visible

H. Oerley*, Dr. Schenk GmbH, Germany

  • Defect detection with muliple images (MIDA) ensures all local defects are caught
  • Visual intelligence: MIDA X (MIDA next generation) ensures optimum classification of detected defects
  • With simultaneous properties monitoring complete quality control with insight into production performance is achieved
  • Smart Factory: Optical Inspection Systems allow deep insight into production performance, rendering it an important contributor to Big Data.

Measuring the maximum pore size of a filter, choosing the most statistically robust parameter

K.G. Brocklehurst, G. R Rideal*, Whitehouse Scientific Ltd, UK

Bubble Point is often used to measure the largest opening in a filter medium, but it can give variable results, firstly because the area of the sample required for testing is infinitesimally small compared to the total area of a filter medium on a roll and so may not be representative of the whole. Secondly, errors may occur in the theory relating to converting the observation of a bubble to a maximum pore size or Maximum Penetrating Particle (MPP).

An alternative method is Challenge Testing, where particles are presented to the filter and those passing measured. In this case, particle shape is an important factor as irregular particles must be aligned within pores in order to pass through what could be a tortuous path. The results are then dependent on the method used for particle size analysis.

To minimise measurement uncertainties associated with particle shape therefore, spherical glass beads should be used in Challenge Testing to determine the Maximum Penetrating Particle (MPP).In this work, analyses of beads passing sand screen filters were performed ...

Characterisation of micron pore size filter media - Comparison of methods

G. R .Rideal*, Whitehouse Scientific Ltd, UK; A. Häkkinen, M. Ängeslavä, Lappeenranta University of Technology (LUT), Finland

In the wet characterisation of fine filter media, there has to be a balance between pore size and open area in order to optimise performance. Traditionally, Porometry has been used, but this is a secondary method where many assumptions have to be made to convert flow rates into pore size. Furthermore, variations between different instruments can occur depending on both the theory used and the operator using the instrument.

Aqueous flow rates, although less dependent on theory, is not a standardised procedure with many media manufacturers building their own systems. Consequently, it is very difficult to make meaningful comparisons for filter media.

To set up methodologies for pore size analysis and aqueous flow measurements that are primary methods whereby all measurements can be traced directly back to NIST without the necessity for the application of theories or computer modelling to derive and answer. The results were then compared to other characterisation techniques including computer modelling...


F5 - Bio-Inspired Innovation of Separation

Day: 23 October 2019
Time: 09:00 - 10:15 h
Room 4B

Session Chair:
Dr. Harald Anlauf

Bionics in application: Superhydrophobic functional textiles for the removal of oil contamination from water

I. Noll*, M. Akdere, T. Gries, RWTH Aachen University; M. Mail, W. Barthlott, University of Bonn, Germany

Oil pollution in water bodies is a serious and globally increasing environmental problem. The focus of public interest is mostly on major marine catastrophes on drilling platforms and in tanker accidents. Much more frequent and ultimately economically and ecologically significant, on the other hand, are everyday oil films occurring on manageable areas such as ponds or harbour basins. These are caused by accidents or carelessness when handling fuel oil tanks, machine oil or internal combustion engines, etc. Oil-binding chemicals are often used to remove such contaminants, which, if not completely removed, cause additional damage. The aim of the presented project is to develop a sustainable way, based on purely physical principles, to remove such oil films effectively and in an environmentally friendly manner.

The approach is based on biomimetic, super-hydrophobic surfaces. It was found that...

Bio-inspired separation - Formulation of an innovation model and ideation tool to boost innovation in the sector of separation technology.

A. Bianciardi*, Politecnico di Milano, Italy

Living systems in nature can count on almost 4 billion years of “R&D” in search for and deployment of solutions to all sort of challenges. R&D via trail and errors and recombination of suitable solutions. Separation is one of these challenges. Being it solids-liquid, solids-gasses, solids-solids, liquid-liquid separation, nature deploys a wide range of strategies and mechanisms adapted to different contexts and with a certain degree of robustness to changes. Separation/Filtration industry could benefit from learning from living systems; to assess and re-address R&D strategy and to innovate products either incrementally or radically.

Existing bio-inspired products on the market have been mainly generated through a solution-driven process: starting from getting intrigued by some biological strategy/mechanism carrying out a specific function, the inventor/innovator imagines a potential application of the strategy to solve a related human problem and conceive a specific design concept for a product or process. Problem-driven approaches, meaning consciously investigating in nature to look for potential solutions of a specific initial problem, are far rarer and are generally supported by Biologically-Inspired Design (BID) approaches and tools. However such BIDs are currently disperse, mainly confined in academic environment, aiming at addressing all problems but with limited field of exploration for specific challenge (repository of biological information limited and broad with consequent reduction in potential for sectoral ideation) and most importantly they have being mainly conceived without involving one of the main target group dealing with innovation: the business sector.

This research explores both innovation models and BIDs and aims at developing and testing a new framework for bio-inspired ideas generation for innovation more tailored for the business sector. The framework is composed of an innovation model provisionally named Constructive Innovation (largely based on Open Innovation models) and a sectoral-driven BID tool named Guild-Based BID. Both components synergistically interact to make the ideation process more effective. Both components have been conceived looking at how nature generates novelties and innovates. To do this a specific methodology, the Biomimicry Thinking approach developed by the Biomimicry3.8 Institute, has been used to structure the research process which foresees a scoping, discovering and creating phase.

Within the research plan this framework will be conceptualize, prepared and tested specifically for the Separation/Filtration industry. Works in progress are presented...

A biomimetic approach for separating microplastics from water

L. Hamann*, Fraunhofer Institute for Environmental, Safety, and Energy Technology UMSICHT, Germany

Microplastics are small plastic particles and fibres. They result from the use of plastics in our everyday life or by weathering of plastic litter that is already in the environment. Each German emits about 4 kg microplastics per year. Due to its long persistence in the environment and its effects on organisms and ecosystems, it is perceived as a major environmental problem. In addition to political measures, eco-designed products, commitment and education of the civilian population, technical developments like filters are essential in order to reduce microplastic emissions. Hence, a biomimetic approach shall inspire new filter technologies, which can be implemented in the entry paths of microplastics. Following the biomimetic design process, suspension feeders are chosen as the appropriate biological models for particle separation. Suspension feeders are organisms that separate food particles from the surrounding water. Because of this ability, they are particularly affected by microplastics, as they confuse microplastics with their natural food. As biological filters, they serve as biological model and inspiration to develop biomimetic filter modules. After searching the literature, 24 suspension feeding types have been selected for further analyses. The mechanisms are described with biological and technical parameters and presented in a morphological box. Comparison is drawn to technical filters to identify similarities and differences, which leave room for innovation. Materials and their design, the combination of more than one separation mechanism and the combination of structure-function systems to sensory systems to adapt to changes in the environment show a high potential for a technical application. Examples are the silk nets of caddisfly larvae, the optimized fluid flow through the filtering pads in whale sharks and the filtering surfaces in the beak of flamingos. Through the systematic analysis, the results shall allow access to information about suspension feeders as biological model to facilitate the development a biomimetic filter module to reduce microplastic emissions.


G5 - Surface Filtration I

Day: 23 October 2019
Time: 09:00 - 10:15 h
Room 1B

Session Chair:
Dr. Qian Zhang

Cleanable filter media go close to zero emission

H.-J. Imminger*, P. Krug, BWF Tec GmbH & Co. KG, Germany

Dust emissions caused by industrial processes are regulated at almost any place on earth by local statutory rules. In almost all cases the emission limits are still defined on a gravimetric basis in mass per volume units, e.g. mg/Nm³.

Obviously, these gravimetric limits are focussing more on coarser or bigger sized particles than on fine dust particulate matter, as the mass of the particle corresponds to the diameter in a dimension of around 10³. On the other hand, exposition of living individuals to the fine dust fraction (PM 2.5, PM 1) is considered very critical under aspects of health and environment. Fine dust is evident as a cause of illness, intoxication and premature death. For this reason, a significant reduction of the fine dust particulate matter should be accomplished, and this is possible by use of sophisticated cleanable filter media in particle filtration processes.

The lecture will demonstrate that the use of an optimized cleanable filter media results in an emission rate that cannot be detected by standard gravimetric methods. By means of a scattered light measurement device only few particles can be detected on the clean gas side of the filter equipment during the filtration process, that will not result in an amount of dust that can be determined by standard gravimetric means.

Filter media achieving that low emissions are newly developed...

Investigating the cleaning efficiency of filters clogged with metallic nanoparticles

N. Khirouni*, D. Bemer, Institut National de Recherche et de Sécurité (INRS); A. Charvet, D. Thomas, Lorraine University, France

Metallurgical processes such as thermal spraying, metal cutting and arc welding emit high concentrations of metallic nanoparticles. These particles pose a real threat to workers in work places and to the environment due to their toxicity. Dust collectors, namely fibrous media, used for the filtration of such particles are currently challenged with a rapid increase of the pressure drop and an inefficient cleaning. Because of their size, the metallic ultrafine particles tend to form a filter cake that is extremely adherent and difficult to detach. This means that filters need to be replaced more frequently, inducing higher operational costs. Industrial feedbacks have also reported that aged deposits can sometimes be more problematic, as the filter cake undergoes some transformation that impedes its removal. Facing all these problems, it is of outmost importance to optimize the industrial filtration systems subjected to metallic nanoparticles.

This study aims to identify the parameters that affect the cleaning efficiency of a filter cake composed of metallic nanoparticles, in order to improve the regeneration of filters...

New test method for bag house filters

R. Heidenreich*, A. Böhme, S. Herrmann, Institute of Air Handling and Refrigeration (ILK), Germany

Based on the revision of the BREF- guidelines in European community and the redesign of the TA Luft in Germany, there will be a further reduction in the emission limit values for industrial plants. According to the current draft of TA Luft 2019, the emission concentrations of air pollution sources with mass flows above 0.40 kg / h are limited to 10 mg/ m³. That is a halving of the current level.

Other legislative changes also in work in case of emission limits in relation to particulate and ultrafine dust concentrations. This also requires an improvement in filter technology and, above all, the creation of test methods that can be used to produce reliable forecast values for emissions. As part of a research project, a measuring method has been developed which takes into account the influence of the filter cake thickness on the degree of separation efficiency. In addition, the degree of separation for an ultrafine aerosol as well as the determination of the total degree of separation for test dust as the basis for the assessment of the separation efficiency was established. The special feature of the new test method is the determination of the separation performance compared to nano-scale aerosols and the determination of the fine dust concentration in the clean gas...


L5 - Cake Filtration - Characterization, Modelling, Scale-up

Day: 23 October 2019
Time: 09:00 - 10:15 h
Room 1A

Session Chair:
Dr. Anthony Stickland

The effect of particle sedimentation on the performance of pressure filters

I.S. Fragkopoulos, F.L. Muller, University of Leeds; N.A. Mitchell, G. Jimeno*, Process Systems Enterprise (PSE) Ltd.; C.S. MacLeod, AstraZeneca; S. Mathew, Pfizer, UK

Pressure cake filtration is commonly used in the pharmaceutical industry for the separation of solids from the crystallisation slurry. The pressure applied has a huge impact on the particles within a cake and in turn affects the resistance of the liquid flowing through the cake. This can cause the cake to compress and clog the filter medium, both of which slow down the filtration process. Although pressure can be increased to maintain a sufficient rate of filtration, this would cause the cake to further compress and/or lead to particle breakage. The filtration performance cannot currently be predicted accurately. Process scale-up is based on extensive experimentation, but scale-up surprises still occur between drug discovery and manufacturing. The main focus of this work was the development of a detailed filtration mechanistic model that takes experimental data and estimates filtration process parameters, so as to enable the prediction and control of the pressure filter performance at scale...

FILOS – Module I: The novel software for the reliable analysis of filtration test data and suspension characterization including washing and deliquoring of filter cakes

I. Nicolaou*, NIKIFOS Ltd, Cyprus

For people dealing with the cake forming filtration of suspensions it is of great importance to minimize the number of experiments, which are needed for the reliable characterization of the suspension behavior with regard to the cake formation and the optional steps of cake washing and cake deliquoring. The optimization of the filtration tests requires the consideration of theory based and praxis oriented mathematical models. Such a theory based approach, is not only a guide for a systematic experimental procedure with minimal number of experiments, but a necessity for the judgment of the quality of the tests, for data correction, and for the reliable determination of all necessary material parameters as precondition for reliable design and prediction of the filter performance for various filter setting parameters.

In this presentation, the physically and experiment based (half-empirical) mathematical models for cake formation, cake washing and cake deliquoring (via gas pressure difference and via cake squeezing) will be discussed. The efficiency model parameters (cake porosity, cake permeability and compressibility, filter medium resistance, cake washing and cake deliquoring efficiency) as well as the necessary minimal number of systematic experiments needed for the determination of the efficiency parameters, will be presented...

FILOS – Module II: The novel software for the reliable selection, performance prediction and optimization of filters for the cake forming filtration of suspensions

I. Nicolaou*, NIKIFOS Ltd, Cyprus

The operation of Filters like Nutsche Filters, Filter Presses, Filter Press Automats, Belt, Drum, Disc and Pan Filters, Candle and Pressure Leaf filters involves cake forming filtration of suspension with the optional steps of cake deliquoring and cake washing.

There is a great need for a user-friendly software for the reliable selection of the proper filter for a given suspension and a reliable performance prediction of the selected filter for different setting parameters and under consideration of changes of the suspension behavior. This task can only be accomplished, if the software uses physically based and practice oriented mathematical models, which include parameters with a physical meaning and not depending on the filter settings (so called material specific parameters).

FILOS is a commercially available, user friendly and worldwide unique software, which not only analyzes filtration tests and reliably determines the necessary model parameters by the use of physically based mathematical models but also uses these equations together with the determined efficiency parameters (see FILOS – Module I) for the calculation of the performance of all above mentioned filter apparatuses for different material, filter geometric and filter setting parameters. This enables, among others, the comparison of the performance of different filters for a given suspension, or the performance comparison of a definite filter and different suspensions. That makes it possible to select the proper filter and determine the optimal settings of the selected filter depending on the material parameters of the given suspension.

Based on a practical example the FILOS Filter Calculation module will be presented...


M3 - Separation of Complex Systems

Day: 23 October 2019
Time: 09:00 - 10:15 h
Room 2

Session Chair:
Dr. Thomas Peters

Technical extraction of EPS from streptococcus thermophilus by dynamic cross-flow filtration on a pilot scale

F. Häffele*, H. Nirschl, Karlsruhe Institute of Technology (KIT); J. Bulla, G. Surber, D. Jaros, H. Rohm, Technical University Dresden (TUD), Germany

Exopolysaccharides (EPS) of lactic acid bacteria, especially those of Streptococcus thermophilus, are branched heteropolysaccharides that are formed in situ during the production of fermented milk products. The ability to form heteropolysaccharides and the specific properties of the mostly uncharged EPS are strain-dependent, resulting in far-reaching possibilities for product design. Due to their potential to improve viscosity, firmness and water retention, for example in desserts, dressings, confectionery or bakery products, they can also be used as additives in foods.

The production of EPS from S. thermophilus is currently only carried out on a laboratory scale, above all with the aim of investigating the properties and mode of action of this hetero-EPS more closely. The challenge in the production of larger quantities of EPS lies above all in the production costs, which essentially consist of the costs for the fermentation medium and the costs for the subsequent isolation of the EPS. Preliminary tests with EPS preparations of different purity from S. thermophilus showed that positive effects are already produced in the product with about 30 % purity. Therefore, the procedure established in the laboratory can be tested for simplifications in order to save production costs for effective preparations with lower EPS purity.

The work deals with the planned, already simplified, instrumental implementation of the laboratory process on a pilot scale. In addition to the presentation of the separation apparatus to be used, the first results regarding EPS yield and purity will also be presented and discussed...

Bagasse extracts fractionation by combination of membrane and chromatographic technologies

P.-Y. Pontalier*, V. Oriez, J. Peydecastaing, ENSIACET, France

The lignocellulosic biomass valorization, for biofuel production, is industrially performed under acidic conditions, mainly at high acid concentration. The aim of this treatment is the production of monomeric sugars that can be transformed into biofuel for the glucose and xylitol for the xylose. Another pathway could be the alkaline extraction that permits both lignin and hemicelluloses solubilization. This approach leads to a more complex extract increasing the difficulties to produce refine fractions.

The aim of this work was to define a process for the recovery a process inspire from the acid’s one to produce several valuable fraction, hemicelluloses, lignin and monomeric phenolic compounds...

Sustainable production in the metal industry – Separation of valuable components from acidic effluents

F. Rögener*, Technical University Cologne, Germany; J. Lednova, M. Andrianova, Polytechnical University Peter the Great, Russia

The quality of stainless steel products is determined by defined surface conditions. During processing, complex structures of tightly adhering oxide layers - referred to as scale - form on the material surface. Additionally, chromium diffuses from the base metal alloy into the scale layers. Both reactions affect the chemical resistance of stainless steel products.

To remove scale and the chromium depleted metal layer from the base metal alloy, a combination of mechanical and chemical processes is applied. Chemical treatment with strong inorganic acids is referred to as pickling. In most cases, pickling of chromium-nickel stainless steels takes place with mixtures of HNO3 and HF. During pickling, the amount of free acid decreases, while the amount of dissolved metal ions increases in the pickling solution. To keep the pickling rate as high as possible, metal ion and free acid concentration should be kept in a certain range. In large rolling mills, continuous regeneration of spent pickling solutions is state of the art. Two general technical approaches for acid regeneration and metal recovery can be distinguished: Total regeneration allows the recovery of both, free acid and metals in form of metal oxides. This can be achieved through a thermal process referred as pyrohydrolysis, or processes combining different treatment steps. Partial regeneration allows the recovery of the still active components of the pickling solutions that have not reacted with the stainless steel surface. In partial regeneration, an acidic byproduct is generated that contains the majority of the dissolved metals from the original pickling solution. To meet the statutory limits for wastewater, this byproduct needs to be neutralized with alkaline solutions. This treatment leads to the formation of the so called neutralization sludge. The sludge - containing, e.g. iron, chromium and nickel hydroxide - must be deposed of. Thus, valuable metals are irrecoverably lost.

To cope with this, options for the recovery of valuable metals from neutralization sludge were investigated. These techniques include...


K3 - Keynote Lecture III

Day: 23 October 2019
Time: 10:45 - 12:00 h
Room 1A

Session Chair:
Prof. Eberhard Schmidt

Air Quality Control & Aerosols

Dr.-Ing. Stefan Haep, Institute for Energy and Environmental Technology e.V. (IUTA), Germany

The control of gaseous and particulate emissions and immissions caused by industrial processes result in filter solutions typically qualified by standardized test methods. The control of non steady loads, typical for real life operating conditions, requires the redesign of filters and the development of advanced testing procedures, especially for multi effect filter systems. Furthermore, this has to be accompanied by adaption and hyphenation of (cheap but robust) online measurement devices, gas and particle sensors and detectors. The latter is particularly of utmost importance for digitalization in filtration technology.

The presentation will cover these aspects, special emphasis is laid on the following topics:
• Potential of new CFD-tools to develop effective fibre structures for the filter design.
• Effect of particle charging to boost the separation efficiency of electret and non electret filter media.
• Methods to qualify multi effect filters under peak load conditions.

Another topic is bioaerosol measurement in the off-gas of cooling towers as a currrent challenge in air quality control...


F06 - Performance Improvements of Nonwovens

Day: 23 October 2019
Time: 10:45 - 12:00 h
Room 4B

Session Chair:
Dr. Kyung-Ju Choi

New development in bag filtration

C. Rodwewald, D. Steinberger*, PALL GmbH, Germany

The new development in the range of filter media, employing Pall’s unique “Laid Over Pleat” technology, is the Vector™ bag filter which gives plants the ability to upgrade their existing bag filters with no capital expenditure requirements. This new filter technology provides enhanced flow capacity and improved filter on-stream life, with a similar filtration performance.

This presentation will illustrate how a 100-year-old bag filtration technology can be improved on a completely new performance level, helping production and processing plants to solve their operational challenges, with a direct retrofit of the existing bag filter.

This advanced filter technology allows for the filtration of an extended range of viscosities while minimizing differential pressure, resulting in reduced energy losses and operational costs. The benefits of the Vector™ bag filter will be illustrated through case studies...

Combinatorial optimization of double-layered filtration media for higher performance

J.R. Gorle*, Parker Hannifin, Finland

For a hydraulic filter to offer a better performance, in addition to a higher filtration efficiency, it must produce an improved dirt holding capacity and lower pressure drop across the porous media. In this regard, the two-layered media packs are considered to yield the best filtration performance, where the coarser pre-filter layer is intended to trap the bigger particles and the main-filter layer captures the finer contamination. A range of materials with specific filtration properties are available for pre- and main-filter applications, and the right combination of these layers is application dependent.

Combinatorial optimization is the technique to find the best possible choice from a finite set of possibilities. This study aims to explore the filtration properties of available media layers using computational fluid dynamics (CFD) to design the efficient two-layered media with prespecified porous properties for each layer...

Flow resistance evaluation through nonwoven filter media

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

Flow resistance evaluation through nonwoven filter media is a critically important factor, especially for the liquid filtration applications.

When the stress is applied, an object deforms, commonly called as rheological phenomena for the liquid.

By utilizing a simple sample holder in a small chamber, the stress was applied to a liquid through nonwoven filter media, such as cellulosic, meltblown, synthetic fibrous and metallic filter media, the flow resistance was evaluated. The stress and responding strain were obtained the geometry of the chamber and measured flow rate.

Significant differences in the flow resistance results were experienced with various fluids used and with the different additives. It is believed that...


G6 - Surface Filtration II

Day: 23 October 2019
Time: 10:45 - 12:00 h
Room 4A

Session Chair:
Prof. Monica Aguiar

A comparative investigation of soluble filter cakes upon contact with liquid droplets

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

Soluble particles are present in the surrounding air and can often uncontrollably find their way into filtration processes. In dry processes, this does not lead to issues or unforeseen filtration outcomes, but upon contact with high humidity or fine liquid droplets, the effect of the mobilized soluble particles on the filtration process remains unpredictable and unexplained. The exposure of soluble particles in filtration processes to fully formed liquid droplets especially leaves many unanswered questions.

The aim of this research is to understand the behavior of soluble particles upon contact with liquid droplets during filtration processes and its impact on the processes’ operational performance.

The movement and rearranging of soluble particles upon contact with liquid droplets are being investigated. As this topic is still fairly new and first results will determine the further direction the research in the field will take, it is crucial to choose a suitable material system, which will show effects in a clear fashion, and is relevant to engineering applications. Multiple material systems, including different salts e.g. NaCl and K2SO4, and filter media were compared in this work and the material system in the focus of further research will be presented. This research is based on a comprehensive literature review and experimental results. The experiments were...

Measurement of the porosity of spherical particle deposit formed by filtration: Discussion on the Peclet number’s effect

J. Nuvoli*, S. Bourrous, F.-X. Ouf, D. Thomas, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), France

High Efficiency Particulate Air (HEPA) filtration is a key point for the safety of workers and environment especially for activities dealing with hazardous materials such as nuclear matter. For industrial risks likely to lead to an important release of particles, consequences of such an event need to be quantified. For the specific case of fire event, particles emitted during combustion are mainly formed by aggregates of spherical carbonaceous nanoparticles. For such situation, recent works lead to a phenomenological model of clogging in which one of the most sensitive parameters is the cake porosity. Up to now, existing models use the porosity as an input data, generally experimentally determined or deduced according to empirical relation. Nevertheless it is essential to describe in a rigorous way this parameter since porosity strongly depends on filtration conditions and particles properties and may evolve during the process. The prediction of this porosity is fundamentals to make filter efficiency and clogging models fully predictive. Many authors have experimentally (Choi et al. 2004, Kim et al. 2009, Elmoe et al. 2011, Liu et al. 2013, Thomas et al. 2014…) or numerically (Mädler et al. 2006, Lindquist et al. 2014) investigated the evolution of a deposit of spherical and fractal nanoparticles according to the transport of the aerosol characterized by the Peclet numbers (Pe). The present work aims to describe experimentally and theoretically, the evolution of deposit porosity, according to analytical experiments with controlled particle production and covering a wider range of Peclet numbers...

Pressure drop evolution during dust loading of hollow-fiber membranes

P. Bulejko*, O. Krištof, T. Svěrák, Brno University of Technology; M. Dohnal, Zena Membranes s.r.o., Czech Republic

This work focuses on the pressure drop evolution of HFMs during particle loading. We tested two types of polypropylene HFMs varying in inner fiber diameter with three different types of dust/aerosol. We used an ASHRAE A2 test dust, a submicron TiO2 powder dispersed using pressure air, and an ammonium sulfate aerosol generated from a solution to simulate a particle laden environment. Data was recorded including pressure drop, permeate velocity, accumulated mass of particles and fan power input until reaching the final pressure drop. After each experiment, the dust cake was weighed, thus obtaining dust-holding capacity. Theoretical models for dust cake pressure drop and energy consumption were compared with the experiment results. The results showed...


L6 - Cake Filtration - Characterization, Modelling, Simulation

Day: 23 October 2019
Time: 10:45 - 12:00 h
Room 1B

Session Chair:
Prof. Urs Peuker

Network model of porous media - Review of old ideas with new methods

S. Esser*, E. Löwer, U.A. Peuker, Technical University Bergakademie Freiberg, Germany

The presentation takes up the old ideas of describing porous media with several tube and network models. The well-known models received from literature gave a good concept of dewatering equilibrium resulting in capillary pressure curves and pore size distributions. However, numerical methods and measurement techniques were not sophisticated allowing to evaluate the models appropriately.

In this presentation, a numerical method based on statistics is introduced to evaluate the network model of FATT from 1956: The porous filter cake structure is implemented as matrix A which elements represent the pore size correlating with the capillary entrance pressure for each pore. The input for the calculations can be any mathematical approximation of a pore size distribution, which can be derived from capillary pressure tests or micro computer tomography (µCT) analysis of the filter cake...

Numerical and experimental investigation of filter cake formation during solid-liquid separation by resolved CFD-DEM coupling

V. Puderbach*, S. Antonyuk, Technische Universität Kaiserslautern; K. Schmidt, IT for Engineering (it4e) GmbH, Germany

Solid-liquid separations require porous filter media for the deposition of the particles in cake filtration processes. The use of woven filter media is common in discontinuous processes, where the filter cake formation is specified by parameters like the filter cake resistance and the resistance of the filter media. The resistances of filter cake and filter media cause a specific pressure drop which consequently defines the process energy effort. In many applications, to describe filter cake formation and pore clogging correctly, the particle-fluid interaction must be considered. The most precise 3D modeling approach to describe these effects is Direct Numerical Simulation (DNS) with resolved CFD-DEM coupling (Computational Fluid Dynamics coupled with the Discrete Element Method). The aim of this work is to describe solid-liquid separation processes by this numerical approach and to validate the numerical results with experimental findings...

Simulation based analysis of the multi-stage filter cake washing

T. Sprott*, A. Brückner, B. Hoffner, University of Applied Sciences Mannheim, Germany

Filter cake washing is an important unit operation in different process industries. In order to reduce operating costs like wash liquid or to reduce filtrate liquid it is possible to use multi-stage countercurrent washing on continuously operated filters. Mechanical dewatering by gas differential pressure can additionally decrease the wash liquid consumption.

The single-stage filter cake washing in laboratory scale in filter nutsches is technically and academically well understood but not all complex mechanisms of the multi-stage countercurrent filter cake washing are clarified yet.

The washing process is typically divided into three regimes. Those are the displacement, the dispersion and the diffusion regime. The first two regimes can be described by the dispersion model. Expanding the dispersion model with the two chamber model for stagnant fluid volumes allows describing the diffusion regime. For the single-stage filter cake washing, analytical solutions are already developed. To solve the multi-stage countercurrent filter cake washing, numerical calculation models are needed. Therefore a simulation tool was developed to provide the opportunity to analyze and evaluate different washing scenarios. Single-stage washing experiments provide the needed parameters for the simulation of the multi-stage filter cake washing.

To validate the model the results of washing experiments in a filter nutsche for two and three stages will be compared with the simulated washing curves based on single stage washing experiments.

Furthermore different simulation results of multi-stage countercurrent filter cake washes will be shown as well as a procedure for a scenario based evaluation for designing cake washing processes


M4 - Ceramic Membranes and Fouling

Day: 23 October 2019
Time: 10:45 - 12:00 h
Room 2

Session Chair:
Dr. Qian Zhang

Ceramic membrane system for drinking water application operating with high flux

M. Kaschek, M. Sartor*, CERAFILTEC Germany GmbH Blue Filtration, Germany; K.G. Gabriel, CERAFILTEC FZCO, Dubai

Brackish groundwater in Middle East region is characterized by very high temperature, high pH, high TDS levels and high hardness. CERAFILTEC - a technology provider for ceramic flat sheet membrane systems - was invited by Saudi Arabia National Water Company (NWC) to demonstrate the performance of the new high flux module at two different locations (Buraydah and Buwaib). In comparison to the experiences in other regions, this water is difficult to treat.

The ceramic membranes were mounted in special high flux membrane modules and operated in a demonstration plant with a capacity of 12 m³/h. The submerged membranes were operated in a dead-end filtration. The demonstration plant was placed in bypass to the operating full-scale trains. Main target was to remove iron, manganese oxide and particles. In order to set the operation directly into stable conditions, a previously used module was installed to avoid a typical performance start-up decline. During backwash mode with drain and discharge of the concentrated sludge waste the formed sludge layer on the membrane was removed.

Different investigations with varying fluxes and water pretreatment were done during the demonstration phase to find out the optimal operation parameter for a high flux operation.

After the start-up and with running pH adjustment, the plant operated stable over both demonstration periods. The filtration start trans membrane pressure after backwash was -0.076 ± 0.138 bar. The applied chlorination led to the expected improvement of the filtered water quality. Excellent results for iron, turbidity and SDI have been achieved.

For both demonstration sites fluxes of > 1000 LMH were achieved marking a technology breakthrough. As the water temperature of the brackish ground water is ~ 40 °C, it is important to keep in mind, that the results need to be normalized (commonly done at 20 °C reference temperature) which means that the normalized flux is around 650 LMH. Nevertheless, this is an excellent value and the results could be achieved due....

Improved fouling resistance of ceramic membranes using organic/inorganic modification for water purification

J. Lee*, J.-H. Ha, I.-H. Song, Korea Institute of Materials Science (KIMS), Republic of Korea

Ceramic microfiltration (MF) membranes have been extensively utilized in water/wastewater treatment. However, membrane fouling is regarded as a serious and poorly resolved obstacle that interferes with the stable water purification process. As a result, it would lead to a decrease in permeate flux / water quality and an increase in the transmembrane pressure / operational costs. Even though the fouled membrane should be periodically recovered using physical / chemical cleaning, they do not provide satisfactory results. For this reason, surface modification is becoming a critical technique for the development of novel ceramic membranes with excellent fouling resistance.

We thus developed the organic / inorganic surface modification techniques which could facilitate the fouling resistance by controlling surface properties of ceramic membranes....

Impact of insufficient membrane and filter properties: Fouling and functionalization

B. Arlt*, Anton Paar Germany GmbH, Germany; T. Luxbacher, Anton Paar GmbH, Austria

In this presentation we will focus on promising methods for membrane and filter characterization in order to improve the filtration efficiency and to increase the life time of these materials. Exemplarily, we will point on two showcases: the fouling behavior of a nanofiltration (NF) membrane and the functionalization of depth filters based on diatomaceous earth (DE).

  1. Identifying the fouling behavior of NF membranes

Employment of polymer membranes for purification and separation processes experiences a steadily growing popularity. Besides their classical application in water purification, polymer membranes become increasingly attractive for the separation and up-concentration of products in the fields of food, biotechnology and pharmacy.

Despite of these versatile application areas, there are restrictions for the optimum use of polymer membranes. The deposition of dissolved or dispersed matter from the feed on the membrane surface, known as membrane fouling, represents an often unresolved challenge especially for polymer membranes and pressure-driven filtration processes (such as nanofiltration and reverse osmosis).

Beside the conventional methods to monitor fouling, such as the monitoring of the transmembrane pressure, we present a highly sensitive method, which is the zeta potential analysis [1]. This parameter at the interface between the membrane surface and the surrounding aqueous solution enables early detection of fouling processes.

  1. Analyzing the modification of water filters

Potable water production requires an efficient and cost-effective technology of drinking water treatment. Depth filters based on diatomaceous earth are widely used for bacteria removal.

Bacteria are unable to penetrate the pores of a microporous DE filter, whereas the significantly smaller viruses can easily pass the filter and harm the consumer. These contaminants can only be completely removed by electrostatic attraction of the virus on the filter pore surface.

As both, the filter and the virus, show negative surface charges, the filter surface has to be modified. Thereby, the zeta potential analysis is a proven tool for measuring the surface charge in a wide pH range.


K4 - Keynote Lecture IV

Day: 23 October 2019
Time: 13:00 - 14:15 h
Room 1A

Session Chair:
Prof. Roger Ben Aim

Dewatering of concentrates and tailings – Large scale duties in the mining industry

Dr.-Ing. Götz Bickert, GBL Process Pty Ltd, Australia

Thickening followed by vacuum or pressure filtration is usually applied for both, products (concentrates) and wastes (mine tailings) in huge quantities in the mining industry. While all three unit operations are long known and well understood, the scale but also the abrasiveness of the material still provides huge challenges.

Conventional, high rate and so-called paste thickening (or deep cone thickening) are all applied to separate the majority of the water added to ground rock for beneficiation, in particular froth flotation. Pre-treatment of the slurry by coagulation and/or flocculation aids in the thickening process and also helps with variable flow rates. As dewatering is the final process step in mineral beneficiation flowsheets, the thickener and filter have to accommodate the changing flow rate coming from the beneficiation plant, which often fluctuates considerably. Thus, thickener control is of upmost importance to achieve a constant thickener underflow product in regards to solids concentration but often more importantly in regards to yield stress to enable pumping of paste. Scale-up of paste thickening has its own challenges due to the drastic change in flow behaviour with only minor changes in solids content.

Tailings dewatering is becoming more and more important due to environmental constrains and also due to public pressure after recent dam failures and resulting loss of life and property. Another important reason for tailings dewatering is water recovery, especially in arid areas such as South Amerika but also Australia. Thus, disposing thickened tailings in ponds is more and more replaced by back-fill of dewatered tailings into underground mines or dry stacked tailings, the thickening, filtration and stacking of huge quantities of mine tailings. This requires vacuum filtration for well filtering tailings but more commonly pressure filtration for fine liberated and finely ground tailings that require higher driving force for dewatering to achieve a solid cake. The large quantities of tailings generated in the alumina, coal, gold, base metals and other mines makes optimising this more than appropriate.

Concentrates - also produced in million of tonnes per annum - are either shipped overseas or directly fed into smelters or other refining processes; often require certain low moisture content. Shipment of concentrates require a moisture content below the TML (transportable moisture limit) to avoid shipment tragedies. Pelletising, smelting or other refining processes also have their own moisture requirements for concentrate filter cakes. With resources becoming rarer, finer liberation produces more difficult to thicken and filter concentrates (and tailings). Thus, higher and higher dewatering forces and more deliberate filtration needs to be applied, increasing the design requirements, operating costs and maintenance requirements. The abrasiveness and with this the wear and tear occurring in filters but also in pumps provide every day maintenance challenges which can be tackled by intelligent and partly simpler designs. Operations also have to account for human factors such as variability and lack of training and skills which is more challenging in boom-and-bust type industries such as the mining industry...


F07 - Advanced Composite Fiber Materials

Day: 23 October 2019
Time: 13:00 - 14:15 h
Room 4B

Session Chair:
Dr. Graham Rideal

Sinterflo® FMC (fibre metal composite) – Development and application

B. Allbutt*, Porvair Filtration Group Ltd, UK; A. Goux*, Bekaert Fiber Technologies, Belgium

Sinterflo® FMC is a true composite material that combines the benefits of both sintered metal fibre and precision woven mesh, thus maximising filtration performance. The FMC structure with integrated Bekipor® technology is composed of random fibre webs and woven mesh structures that are sintered to form a homogenous yet multiple layered structure, designed to deliver performance, strength and practicality in cleaning.

Controlling the thickness of the fine fibre at the flow inlet face ensures the permeability is maximised whilst providing a surface capable of rapid filter cake development. The asymmetric pore structure provided by this material is critical to the development of the filter cake and the in-situ ability to clean through pulsejet operation. A coarse fibre structure embedded within the composite promotes a high integrity sintered interface along with a more open structure to provide flow distribution in operational flow direction and diffusion in the reverse direction when cleaning.

The woven mesh structure provides integral support for the filter element, as well as coarse fibre structure evident on the clean/downstream side of the filter media to further enhance the flow distribution and diffusion of the pulsejet flow for the cleaning of the filter media. This structure provides higher...

The advantages of metal fiber media for aircraft hydraulic filtration

J. De Baerdemaeker, A.Goux, M. Van Hooreweder*, J. Mothersbaugh, Bekaert Fiber Technologies, Belgium

The industry standard for filter media used in hydraulic filtration has, for many years, been typically glass fiber or cellulose based. Metal fiber media, however, is on the rise as a preferred medium.


The Engineering Operations Department of a major operator carried out an investigation into the cause of malfunctioning hydraulic equipment in some of their helicopters. Their researchers determined particulate contamination in the hydraulic fluid to be a cause of the malfunctioning. This led to a review of the filtration media utilized for the filter elements. The filtration media review, which took over a decade, compared glass fiber and metal fiber filtration media in a number of tests. These tests included the development of the Dynamic Filtration Efficiency test method, which mirrors real world operation more closely, and 1000’s of hours of in-flight testing. The tests showed that Bekaert metal fiber media provides a much better fluid filtration compared to glass fiber media (NAS Class 0 versus NAS Class 9). It also proved that the improved fluid cleanliness significantly reduced the need for maintenance and component replacement. As a result, maintenance costs for the helicopter fleet dropped over $4M in one year.

In our presentation, we will detail the production process of Bekaert metal fiber media, its inherent properties and how it outperforms other media when used in hydraulic fluid filtration. We will outline the contamination problem inherent to hydraulic systems. We will share the findings of external reviews and the significant cost savings high-end users made by applying Bekaert metal fiber filtration media in their hydraulic systems...

Methods to increase the filtration performance of metal woven wire cloths

M. Müller*, Spörl KG, Germany

With their narrow pore size distribution metal woven wire cloths guarantee an excellent separation and classifying accuracy. Due to their high chemical, thermal and mechanical resistance, wire meshes as metallic filter media can be used in demanding operation conditions, for example in the form of high process pressures and temperatures or sharp-edges particles which have to be deposited. Depending on the combination of the warp wires and the weft wires during the weaving process, the production of different types of weave with different aperture sizes and filtration behaviors is possible. The filtration performance can be assessed based on the initial pressure loss, absolute pore size, dirt holding capacity, load-depending separation efficiency and cleaning behavior. In the paper, these 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. The performed experimental investigations show, that...


G7 - Filter Test Systems I

Day: 23 October 2019
Time: 13:00 - 14:15 h
Room 4A

Session Chair:
Dr. Jörg Meyer

Filter media testing in accordance with ISO 16890

M. K. Schmidt*, PALAS GmbH, Germany

Air pollution concerning Fine Dust in- and outdoors are currently one of the most discussed topics in public. The new ISO 16890 provides new filter classes ISO ePM1, ISO ePM 2.5 and ISO ePM 10 to forward the operator an idea how far a certain product may reduce the amount of fine dust in his application.

These efficiency values are based on the fractional efficiency test data, long time known from Standards as EN 779 and ASHRAE 52.2. To evaluate the efficiency by particle size, particle counters (ISO 21501-4) or Aerosol spectrometers according to ISO 21501-1 working with the scattered light principle are used. Afterwards the measured efficiency is transferred into ISO ePMx values based on typical ambient air distributions as given by ISO 16890-1.

Usually, according to ISO 16890, the ISO ePM values are tested at the complete filter element. The efficiency of the complete filter element is resulting from the design of the element as well as the characteristics of the filter material used. The difficulty is now to estimate which filter class results if a certain material is used without manufacturing a completely new element.

Therefor Palas® has designed a new filter material test system, which can perform the whole test procedure according to ISO 16890 at the flat sheet media. An automatic software procedure to evaluate the data measured and automatically converting efficiencies into the ePM values is available.

As the main air flow for such a test is, depending on the size of the sample, up to 120 times lower than for the complete element....

Two years of filter testing experiences according to new ISO 16890

C. Kappelt*, A. Rudolph, C. Peters, S. Große, Topas GmbH, Germany

The aim of the new standard ISO 16890 for performance evaluation of air filters for general ventilation was to harmonize existing local standards such as the ASHRAE 52.2 which is common in the United States and EN 779 which was developed in Europe. Since July 2018 the EN 779 is finally withdrawn.

The new standard intends to achieve more realistic laboratory filter evaluation, which has the result, that the test procedure becomes more complex. The more realistic laboratory filter evaluations are realized by rating particle fractions, now the particle sizes from 0,3 µm to 10 µm are considered. Furthermore an additional aerosol KCl is used, the whole filter is discharged with IPA. ISO A2 fine dust is used for optional loading tests. Also the previously known filter classes F,M and G, are replaced by the filter classes ISO ePM1, ISO ePM2,5 and ISO ePM10. To classify the filters, the minimum efficiency values ePM1,min and ePM2,5,min have to be used in addition to the efficiency values ePM1, ePM2,5 and ePM10,

This paper will present a latest state of the art testing methodology which fulfils all the new requirements of ISO16890. The focus of this paper will be the description of the setup of a fully automatic filter test system with two optical particle counters. Furthermore all important key components including the discharging according to ISO 16890-4 will be presented, which are necessary for the determination of the filter performance parameters. As well as the evaluation of the obtained measurement data and the creation of a summary report according to the ISO 16890 standard in which all parameters are determined and recorded for a direct interpretation of the test results as well as the filter classification...

Aspects of air filter testing: dust loading

M. Stillwell*, Particle Technology Ltd, UK

Test standard ISO 16890:2016 (Air Filters for General Ventilation) is now used in the filtration industry to classify the performance of air filter elements in terms of their particulate removal efficiency (ePMx), initial arrestance and test dust capacity. This applies to filter elements used in heating, ventilation and air conditioning systems (HVAC).

Eurovent is the European industry association for HVAC filters. Their sub-unit, known as Eurovent Certita Certification, has a certified performance scheme for participating filter manufacturers. The performance data is collected by approved independent test laboratories and is used to verify the claims made by the filter manufacturers. This helps those who need to specify air filters for certain applications to select with confidence the most appropriate type of air filter.

The measurement of air flow resistance of a filter element is very important because this data is used to determine the energy rating of the filter. The 3rd edition of Eurovent document 4/21 (2018) describes the test method and calculations. It is based on the dust loading test specified in ISO 16890:2016 part 3, except that it requires a minimum of eight separate dust loading stages, including the initial dust loading of 30 grams (or the quantity of dust required to produce a 10 Pa rise in differential pressure) and the final target pressure drop, which is dependent upon the filter type. The average pressure drop across the filter is determined and then used to calculate the annual energy consumption (kWh/year). Eurovent’s rating standard RS 4/C/001-2019 specifies the energy rating classes based on the annual energy consumption and the ePMx rating of the filter.

The rate at which the differential pressure increases across a filter with respect to the quantity of dust fed to the filter depends upon the physical properties of the test dust. One aspect of interest in this work is the significance of electro-static charges within the aerated dust on the measurement of differential pressure. The results from tests using Particle Technology’s accredited ISO 16890 test rig, with industry standard equipment will be discussed...


L7 - Cake Filtration – Particle Washing

Day: 23 October 2019
Time: 13:00 - 14:15 h
Room 1B

Session Chair:
Prof. Ioannis Nicolaou

Washing performance prediction of horizontal vacuum belt filters for different wash modes

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

Generally washing of the filter cake sets in immediately after cake formation, ideally just when the filter cake formation is finished, i.e., at saturation one. Sometimes an intermediate deliquoring stage is allowed for before washing liquid is provided. While the mother liquor remains undiluted during this stage, the rewetting of the filter cake may pose a problem for subsequent washing. Sometimes re-slurrying of the filter cake with wash liquid and renewed cake formation can be an option. Washing is a cross-flow operation where the filter cake moves horizontally while the wash liquid flows through the filter cake vertically. When the wash liquid is collected stage-wise, it can be re-used in co- or counter-current operation mode or as a reflux.

Washing aims for the removal or exchange of the mother liquor by another liquid. The targeted product could be the clean and maybe ultimately mechanically dry solid product, the mother liquor itself or its dissolved constituents. While filter cake deliquoring is based upon liquid displacement, a combination of displacement and diffusion/dispersion mechanism is relevant for cake washing. Liquid displacement is not a perfectly homogeneous process but occurs predominately at larger, through-pores while narrow, dead-end pores are hardly accessible. Clearly excessive washing in terms of more wash liquid and/or washing time will improve the situation but the gain is sometimes comparably small. Systems that are particularly affected by this phenomenon can be improved by re-slurrying with the penalty of more wash liquid and higher expenses and complexity in set-up.

Conventional, discontinuous filter tests are carried out consisting of...

Characterization and simulation of displacement washing processes in filter cakes

B. Hoffner*, University of Applied Sciences Mannheim, Germany

Displacement washing of filter cakes is common in various industrial fields. The objective is to separate dissolved substances from the filter cake like salts, acids, bases, and colorants by means of a wash liquid. The wash liquid penetrates the filter cake and displaces the mother liquor largely. This paper refers only to gas differential pressure driven processes.

The displacement washing process is usually applied to filter cakes that do not show shrinkage, cracks, and wall detachment. In other cases, dilution washing processes are applied. However, due to the low specific wash liquid consumption a displacement washing is the first choice to be considered. An additional benefit of a displacement washing process is the easy integration into a process chain consisting of the cake formation step followed by one or several subsequent washing and dewatering steps.

Typical machines of operation are continuously and batch-wise operated filter equipment such as belt filter, drum filter, nutsch filter, filter press …

The progress of the washing process is commonly characterized by means of a washing curve: The amount of residuals is plotted as a function of the amount of wash liquid used. This type of curve shows usually three distinct regions, reflecting the different mass transport mechanisms, commonly named as...

Dewatering and imbibition effects on the multi-stage cake washing

A. Brückner*, T. Sprott, B. Hoffner, University of Applied Sciences Mannheim, Germany

The continuous multistage cake filtration is used in many industrial sectors (e.g. chemical, pharmaceutical, energy). In order to reduce the amount of wash liquid and filtrate by having a high concentration of filtrate at the same time, the wash liquid is frequently conducted in countercurrent washing.

A dewatering step after cake formation (pre-dewatering) and an intermediate dewatering step between the washing steps are technically unavoidable. However, they can be used to remove contaminated liquid. Through an intense undersaturation in the pre-dewatering step, the contamination discharge of the filter cake reduces significantly. The filter cake can be dewatered to an equilibrium saturation. In order to describe the impact of dewatering on the whole washing process, it has been proven effective to simultaneously regard the contamination and the cake saturation as a function of process time. The parameters saturation (S), contamination (X*), washing ratio (W), time (t) must, therefore, be determined after each experiment. When the filter cake passes the washing steps (W1, W2,…), it will be filled up with wash liquid leading to a saturation increase. For a rewatered filter cake could also be determined an equilibrium saturation.

The influence of pre-dewatering and intermediate dewatering between the single washing steps were investigated in laboratory experiments with the nutsch filter. The effects of dewatering on a multistage filter cake washing can be..


M5 - Process and Waste Water Treatment

Day: 23 October 2019
Time: 13:00 - 14:15 h
Room 2

Session Chair:
Prof. Wilhelm Höflinger

Recent developments in industrial wastewater treatment by aerobic and anaerobic Membrane Bioreactors

F. Rögener*, M.P. Betz, L. Papendorf, S. Steinhauser, Technical University Cologne, Germany

Membrane Bioreactors (MBRs) combine biological wastewater treatment and membrane filtration. There are two basic options for the operation of bioreactors: While anaerobic microorganisms require oxygen for the degradation of organic pollutants, anaerobic microorganisms require the absence of oxygen. The two concepts are applied for the treatment of different kinds of wastewaters.

Aerobic MBRs is especially employed for the treatment of municipal wastewaters with an average chemical oxygen demand (COD) of about 300 – 1,000 mg/L. The main byproduct is CO2. In anaerobic MBR technology (AnMBR), biogas is generated as a valuable by-product; compared to aerobic MBRs, the amount of excess sludge is small. Anaerobic digestion has the ability to handle highly contaminated organic wastewater. Current commercial high rate anaerobic reactors can deal with a COD of up to 60,000 mg/L. Thus, this process is especially suited for the treatment of wastewater generated in the food industry (e.g. breweries, dairy industry), and in the pulp and paper industry. However, this technology has not been well established technically, yet.

In AnMBRs, suspended solids concentration can reach up to 30 g/L. For a wide range of wastewaters, COD removal of about 90 % could be achieved at temperatures about 30 °C and a methane production of 0.25 to 0.35 m³ CH4/kg COD could be reached. The advantages of AnMBRs, as compared to conventional aerobic wastewater treatment, are...

Membrane bioreactor as polishing step in the treatment of galvanic wastewater

B. Mayr*, T. Garstenauer, EnviCare Engineering GmbH, Austria

In galvanic industry wastewater is formed as a byproduct in surface treatment processes of metallic compounds. The common primary treatment steps are flocculation and precipitation. Depending on the applied unit operations the filtrate of the subsequent chamber filter press usually contains significant amounts of COD, heavy metals (e.g. zinc, iron, chrome) and also filterable solids. In order to reach direct discharge quality a final treatment step is necessary.

In membrane bioreactors (MBR) biological wastewater treatment is combined with membrane technology. Organic compounds will be degraded under aerobic conditions and the activated sludge is confined in the biological system by micro- or ultrafiltration membranes.

Of course, heavy metals cannot be degraded by microorganism, instead the metals are removed from the wastewater through various mechanism such as incorporation of precipitated metals in sludge flocs, adsorption, binding and complexation of metal ions in extracellular polymeric substances (EPS) and diffusion of metal ions into the activated sludge flocs. These heavy metals can also have inhibiting or toxic effects on the biomass in a biological wastewater treatment system.

This article deals mainly with design, construction and operation of an MBR-plant as polishing step in the cleaning of galvanic wastewater.

The project started with a MBR pilot plant, which was installed and operated during a period of three months, in order to evaluate the fundamental suitability of this treatment process. The pilot test showed that the MBR-process is suitable to reach direct discharge quality for the filtrate from the chamber filter press. Based on the results from the pilot phase, a large-scale plant was designed, constructed and operated.

After one month of operation in the pilot phase the COD concentration in the outflow was...

Cost-optimized sustainable water management in the mining industry based on membrane processes

T. Peters*, Membrane Consulting, Germany

No other area of industrial activity in our world exhibits such a diverse and multi-faceted water-related field of conflict as actually the mining industry. The influencing factors range from the procurement of the absolutely necessary process water with drinking water quality in areas of water shortage to the environmental damage caused by wastewater originating from mining related treatment processes. This includes its large-volume storage that cannot yet be assessed from a long-term perspective and the related increase of the life-threatening potential. In addition to the water supply problem in arid regions and the disposal problem for tailings, for example, more stringent environmentally-specific legal requirements - which are intended to contribute to increasing the protection of human health and the ecological balance of water bodies – and increasing public awareness are also leading to significant changes in water management internationally and, in the opinion of leading economic experts, are forcing short-term changes in corporate strategy in the mining industry. This problem area also includes acid mine drainage (AMD), the acidic saline mine water resulting from leaching processes in the mines.

The requirements for more efficient water treatment in the mining industry have led to the development of sustainable and cost-optimized processes for the treatment of water or wastewater which have not yet been used in water management in these applications but have proven themselves elsewhere. In addition to the optimization of conventional processes, this increasingly includes the pressure-driven membrane processes microfiltration, ultrafiltration, nanofiltration and reverse osmosis. Their mode of action and the possible applications in the mining industry that can be derived from them are discussed using examples.

It should be noted that, depending on the type of the substances to be treated and the required discharge limit values for the remaining liquids, specifically adapted processes or process combinations can again be used for an efficient treatment of the residual substances that originate from the individual processes. The range of possibilities to be oriented towards economic and ecological standards extends from the reuse and extensive use of all recyclable materials still contained in the residues to waste water-free (ZLD = Zero Liquid Discharge) or residue-free operation.

It should also be mentioned that the process related details and interrelations addressed in the presentation are intended to provide a phenomenology-based basic understanding of suitable processes for the treatment of water, waste water and process fluids, which in collaboration with experts can then be used for the investigation, planning and implementation of successful large-scale applications.


G8 - Short Oral Presentations

Day: 23 October 2019
Time: 14:45 - 16:00 h
Room 4A

Session Chair:
Dr. Jörg Meyer

Simulation and experiments on the cake formation in dust filtration with fabric filters

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

In terms of particle removal from gases with surface filters, the periodic building and detachment of particle layers decisively determine the operating behaviour and the performance of the filter. The surface structure of textile filter media including the near-surface, porous transition area between the dust cake and the filter medium is of fundamental importance in view of dust cake formation and detachment. In practice, various surface finishes like singeing, calendering, etc. are used on empirical basis to improve the operating behaviour of textile filter media by modifying the surface texture. For targeted development and implementation of new filter media there is a need for a systematic investigation into the correlation between the surface structure of textile filter media and their operating behaviour on a quantitative basis.

In the current study, the structure of generated dust cake on model fabric filters is investigated by simulation for cake forming dust filtration via calculation of particle trajectories. The changes in the dust cake structure and in the operating behaviour of the filters are evaluated and analysed by systematic variation of the filter surface structure. For comparison, results of corresponding experimental investigations with differently structured needle felts are presented and discussed together with the simulation calculations...

Experiments on the rearrangement behaviour of dust in wall flow filters

S. Jüttermann*, M. Kaul, E. Schmidt, University of Wuppertal, Germany

Wall flow filters are used for exhaust aftertreatment in passenger cars and commercial vehicles in order to comply with the legal requirements regarding the emitted particulate mass. The particles to be separated are primarily carbon-based components that are formed in the engine compartment due to incomplete combustion. With increasing operating time, the backpressure behaviour of the diesel particulate filter (DPF) increases due to the high mass of separated particles. For optimum operating performance, the filter must be regularly regenerated actively and/or passively. As a result of the regeneration process diesel ash remains in the filter as a cumulative regeneration residue. This has a particular influence on the separation and backpressure behaviour of the DPF due to different deposition pattern.

The focus of this research project is to describe the storage and rearrangement of the diesel ash within the individual DPF channels and to develop an understanding of the processes inside the filter...

Investigation of the filtration kinetics of depth filter considering tomographic data

K. Hoppe*, Anhalt University of Applied Sciences; L. Wischemann, G. Schaldach, R. Zielke, W. Tillmann, M. Thommes, D. Pieloth, Dortmund University; D. Renschen, DMT GmbH &Co.KG, Germany

Fibrous depth filters are frequently used in various civil and industrial applications. The loading behavior of fibrous filters determines the evolution of pressure drop and filtration efficiency during their service time. The pressure drop limits the service time and determines the energy costs of the filtration system. For a sustainable and efficient filtration process, knowledge about the loading behavior inside the material is evident. It is well known that the structure of the filter media highly determines the loading behavior and offers the potential for optimizations.

In this work, a calculation method for the filtration kinetics of fibrous depth filters based on tomographic structural data is presented...

A new set-up for characterisation of particle and agglomerate detachment from an elastic single fibre exposed to airflow at low velocity

L. Poggemann*, F. Klingel, J. Meyer, A. Dittler, Karlsruhe Institute of Technology (KIT), Germany

Depth filters are used in air-conditioning and cleanroom technology for removal of particles from gases. In those applications the particles deposit and accumulate inside the fibrous filter media causing an increasing separation efficiency, pressure drop and hence more energy consumption. Currently filter systems consist of a static filter structure that is not able to adapt oneself to the changing process conditions. A new elastic fibre could be an opportunity to introduce a new kind of filter systems. Those filters could adapt its mutable fibre diameter and porosity to operation conditions, like particle load, particle diameter and flow velocity, in order to attain necessary collection efficiency with minimal pressure loss and less energy consumption.

Investigations on the single fibre collection efficiency of particles and the deposited particle structure on the fibre are done with a new constructed single fibre-stretching set-up during and after a controlled stretching process. The size, number and morphology of detached particles structures are characterised by an optical particle counter with two consecutively detectors, measuring volumes and a laser band technique for bigger agglomerates. These measuring systems and the single fibre are arranged perpendicular to the direction of aerosol flow. The stretching itself is done by a fibre-mounting with piezo-actuators for controlled movement. The fibre movement is varied in stretching velocity and the number of stretching cycles. Further investigations on stacked fibres should be done in the same way. At the end, the results of the single fibre experiments should be exemplary for all the fibres within a depth filter.

Preliminary tests with an elastic single fibre and glass particles at a test stand showed that...

Experimental characterization of reactive particle structure re-arrangement and detachment from a single fibre exposed to hot air flow

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

Depth filters are used in air-conditioning, cleanroom technology and exhaust gas treatment. Particles are separated inside a porous structure where they form particulate structures. High flow velocities are needed to detach particles adhering to the filter media, for example velocities greater than 1 m/s are needed for detaching particles of 10 µm in diameter. Velocities in filtration processes are lower because particle bounce occurs at [endif]--> 1 m/s, reducing separation efficiency. For this reason, detachment of separated particles does not happen in most filtration processes. New findings show that reactive components in deposited particle structures can cause deformation and detachment even at low flow velocities. Understanding of these phenomena is necessary to improve soot particle filtration in fibrous filters. In the scope of this project first experimental results regarding deformation and detachment of soot agglomerates on/from a single steel fiber exposed to hot air flow are presented...

Round robin test to evaluate the test method according to ISO 16890 – Air filters for general ventilation

T. Schuldt*, F. Schmidt, University Duisburg-Essen (UDE); E. Däuber, T. Engelke, Institute for Energy and Environmental Technology e.V. (IUTA), Germany

Since 1 July 2018 the standard for testing air filters for general ventilation is ISO 16890. Along with the introduction of new filter classes there are also new requirements for the test. One example is the electrical discharging of the filter: it is now performed with vaporized isopropyl alcohol (IPA) in a conditioning chamber. The previous method in Europe was the dipping of filter media into liquid IPA (EN 779). The reason for change was the observation that efficiencies of electret filter media treated with saturated IPA vapor resulted in significant lower efficiencies compared to measurements of filter media treated with liquid IPA (Cai 2010). Other changes include the use of DEHS (0,3 µm to 1,0 µm) and KCl (1,0 µm to 10,0 µm) aerosols to measure the filtration efficiency and the elimination of a dust-loading test (except for filters with ePM10 values below 50 % in which case a gravimetric efficiency has to be determined). To specify the reproducibility and to evaluate the test method according to ISO 16890 a round robin test was performed.

Eleven laboratories participated in the round robin test. One of them provided the filters which were equally manufactured and consisted of polypropylene fibers. Each laboratory was free to use their equipment with the exception that it had to fulfill the specifications laid out in ISO 16890. This resulted in the use of different optical particle counters (OPC), different atomizers, different conditioning chambers and so on – a perfect situation to evaluate a test method.

The measurements of the pressure differences and the filtration efficiency before and after IPA treatment showed...

Generation and characterisation of reactive and inert aerosols

J. Thieringer*, H. Werling, J. Meyer, A. Dittler, Karlsruhe Institute of Technology (KIT), Germany

Particle filters, e.g. diesel or gasoline particle filters (DPF/GPF), are applied to reduce emissions of combustion engines and have become a standard component in exhaust aftertreatment systems. The emission standards regarding particulate matter (PM) and particulate number (PN) concentrations are getting stricter hence a better understanding is essential for the optimisation of the exhaust treatment. Due to particle deposition and the resulting layer formation in the filters, the pressure drop and energy consumption increase during operation. In order to reduce these influences on the operating conditions, various process parameters and their effects on the filtration process of reactive-inert aerosols have to be identified.

To investigate the operational behaviour of cross-flow-filters, test aerosols are used to characterise the formation of particle layers and to determine structural layer changes due to break-up and rearrangement of deposited particulate matter. Due to the variety of reactive/inert aerosols, various particle size distributions (PSD) and morphologies are identified and have to be replicated. For the separation of reactive and inert particles, two different generation methods are used to produce different compositions of aerosols. The inert particles (ash) are generated with an oil-mist and a subsequent incineration in an oven. Due to the introduced oxygen, the hydrocarbons are fully oxidised to carbon dioxide and water vapour. The process parameters, oven temperature, oxygen concentration and residence time, are varied. The method for the generation of reactive particles (soot) is based on a soot generator where soot is formed with propane and a subsequent diffusion flame pyrolysis. In this process, stable operating points for the reactive particles were detected.

As expected, the inert aerosol properties, e.g. particle size and concentration, are...

Characterization of an electrostatically charged water spray for reducing fine dust emissions

M. Zillgitt*, E. Schmidt, University of Wuppertal, Germany

Handling with bulk materials, such as sand, gravel, coal or granules, dust is produced as a function of material-specific properties. From the perspective of process engineering the challenge here is to reduce the emission of the fine dust originating from diffuse sources, in particular PM2.5. Therefore, water dispersing systems are often used at conveyor belts, crushers or on stockpiles where water spray is generated by two-fluid nozzles. Dust particles are wetted depending on the droplet size distribution and the amount of water used. The binding between droplet and dust particle increases the particle mass and results in a faster sedimentation. However, due to the low inertia of dust particles (PM2.5), a large amount of water is necessary in order to achieve a sufficient separation efficiency.

For resource and energy efficiency, a new water dispersion system is developed. The goal is to increase the probability of precipitation while reducing water consumption...

Experimental methods in dust emission prediction

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

Dust emissions can be understood as the release of the particles from bulk solids in consequence of handling. These emissions can cause an explosive atmosphere, lead to long-term sickness or environmental pollution. In order to reduce all this kind of possible hazards reliable prediction methods of dust emissions during the handling of bulk solids have to be developed. For this reason, common experimental methods, representing different handling scenarios, are modified and used for investigations.

The paper deals with the experimental methods, their modifications and the first results gained...

Industrial tests of filter bags "3DESA filtrpatron" with increased filtering area

V.V. Chekalov*, DESA Co. Ltd., Russia

One of the ways to modernization of the existing equipment of dust filtration is to use in the filter houses the filter bags with increased by surface of filtration. The other way is concluded in use in bag filter houses the filter bags with increased by surface of filtration at development and design of new compact equipment of dust filtration.... DESA Co.Ltd. brings on the market the new technology 3D Economic System of Aspiration using in the filter houses the filter bags "3DESA filtrpatron" are made from nonwoven filtering materials Patent EP1459796 (golden medal salon INVENTIONS GENEVA 2013), patent RU 2283683.....


G9 - Short Oral Presentations

Day: 23 October 2019
Time: 14:45 - 16:00 h
Room 4B

Session Chair:
Prof. Gerd Mauschitz

Experimental assessment of deposition of synthetic fibrous dust within the ductwork of residential ventilation systems

N. Alessandria, S. Sedlar, G. Mauschitz, T. Laminger*, Technical University of Vienna; A. Svec, Fa. Adalbert Svec, Germany

New residential units are typically equipped with controlled room ventilation systems with heat recovery to ensure a reliable and controlled air exchange. With dust deposited within pipes, outlets, bends, reductions and filters, the rise in power demand causes higher operating costs. Furthermore, deposed dust layers can be a breeding ground for germs, fungi or other pollutants. Therefore, such systems require regular maintenance, best of all by professionals who carry out special hygiene inspections and cleanings. To minimize dust deposition within the ductwork, operation costs and additional hygienic problems, for example simulation tools and practical guidelines are absolutely essential.

Predictive models for dust deposits in pipes and fittings for room ventilation systems still are insufficient for complex dusts consisting of fibers and particulate materials. The aim of this project is therefore to assess residential ventilation systems regarding the dust deposits of various pipe fittings under controlled conditions....

Controlling specific properties of paper wet laids for air filtration by means of hydro-entanglement

R. Heidenreich*, Institute of Air Handling and Refrigeration (ILK); T. Schulze, Thüringisches Institut für Textil- und Kunststoff-Forschung e.V.; F. Gebauer, Papiertechnische Stiftung (PTS), Germany

Air filtration is a „Green Market“. But, this time filtration materials will be classified more by functional aspects than sustainable. Actual tendencies leading to small filter housings and lower use of energy. That’s why filter materials are more and more made by synthetic fibers. Technical features better can be adjusted with polymer chemistry. But this is not “Green”.

Therefore a research project was carried out to push possibilities of natural fibers – paper.

The project aim was to control the porosity of paper by reorienting its fibres through hydro-entanglement in the paper machine. The wet-laid nonwovens will be converted to novel and functionalized paper filter media that can be used to make deep filtration air filters from renewable raw materials and with performance characteristics and performance data comparable to synthetic- / glass-fibre-based filter media. The novel air filter media should offer high filtration efficiency and dust holding capacity as well as comparatively low pressure losses at high layer thickness. The results of the project showed that...

Deodorizing filters containing visible light photocatalysts for air purifiers

Y. Lee*, H. Kim, D. Lee, LG Hausys R&D Center, Republic of Korea

Indoor air quality has received tremendous attention these days because people generally spend more than 80 % of their time in indoors. This indicates that people are placed in more risky situation form inhalation of pollutants due to the level of pollutants in indoor environment is higher than in outdoor environment. The ventilation is known as the most convenient and effective solution to hedge the risk but it’s not in metropolis such as Seoul because the ventilation could migrate particulate matters from vehicular exhaust or industries. Therefore, air cleaning by air purifier is considered as the most feasible option to improve indoor air quality so air purifier market size has been skyrocketing.

At the current stage, photocatalytic decomposition has shown to be a promising and effective technology for pollution control. Unlike traditional method such as adsorption by activated carbon which merely relocates pollutants from indoor environment to deodorizing filter, photocatalysts actually disintegrate pollutants to CO2 and H2O. However, photocatalysts are still immature to replace activated carbon because the decomposition rate of pollutants by photocatalysts is quite slower than the adsorption rate of activated carbon. In addition, photocatalytic efficiency is decreased with decreasing pollutant concentration which represents indoor environment. Therefore, we believed that adsorbents and photocatalysts must be combinated to maximize the efficiency of indoor air quality improvement by air purifier...

Evaluation of filtration performance of filters with nanofibers and HEPA

A.I. P. Salussoglia*, V. G. Guerra, M.L. Aguiar, Federal University of São Carlos, Brazil

Air pollution is a serious environmental and public health problem that can be associated with cardiovascular and respiratory diseases, as reported by recent studies. Filter media is commonly used to control and removal particles from the air. Recently, the use of nanofibers applied to air filtration is increasing.

In this context, the aim of this study was evaluate the filtration performance of filters with nanofibers and HEPA. The results showed that collection efficiency and pressured drop of HEPA filter were...

Efficiency of collection of particulate matter and maximum pressure drop of precoating

B.K.S.A. Andrade*, M.L. Aguiar, Federal University of São Carlos; R. Sartim, Federal University of Espírito Santo, Brazil

A simple, cheaper and alternative pretreatment for increasing the collection efficiency of fine particulates in nonwoven filter media is precoating, which consists of coating the inside and the surface of the nonwoven filter media with a particulate material forming a layer of initial powder. This layer prevents the particles from penetrating the filter medium and causes clogging. It is also responsible for the clogging which is the initial formation of the pie, acting as a new filtering element ensuring surface filtration. Thus, the purpose of precoating is to assist in the separation of the micrometric and nanometric particles, as well as to ensure that the gas flows freely through the filter medium, improve the performance of the filter sleeves, increase filter media life and facilitate cleaning, promoting better detachment of the pie from the filter media. The choice of the powder to be used in precoating must be judicious because it has a direct influence on the filtration efficiency as well as obtaining the clogging point and the pressure loss at which this point is reached. Thus, the objective of this work was to determine the precoating powder and the precoating limit pressure drop, which ensures the clogging of the filter medium to obtain the best collection efficiency in fine particle filtration from the secondary dusting of the steel plant of a steel industry...

Collection efficiency of a bag after 3 years of use in a bag filter

C.R. de Lacerda, B.K.S.A. Andrade*, M.L. Aguiar, Federal University of São Carlos; R. Sartim, ArcelorMittal Global R&D, Brazil

One factor that must be taken into account when selecting the filtration bag is the quality of the seam, which can be a point of powder leakage and increase the concentration of particulate matter released into the atmosphere. The objective of this work was to characterize a bag made of aromatic polyimide (PI) fibers, after 3 years of use in the sintering unit of a steel mill, in order to evaluate the particle collection efficiency after this time, especially in the part that has the seam.

Filtration cycles were performed on the equipment based on VDI 3926, which simulates the industrial operation of a bag filter, in order to verify if the seam of the bag interferes in the collection efficiency of the submicron particulate matter. For comparison, the tests were performed on a bag with 3 years of use, both in the seamed part and in the seamless part. The powder from the primary sintering was used as the particulate mater, which was collected in the silo that is downstream of the bag filter. The following characteristics were obtained...

Effect of the temperature on the degradation of polyphenylene sulfide non-woven bag-filter media by NO2 gas with a continuous-flow exposure method

K. Fukui*, K. Ito, M.I.F. Rozy, T. Fukasawa, T. Ishigami, Hiroshima University, Japan

PPS non-woven fabric is one of the most cost-effective filter media used in processing the flue gas of waste incinerator facilities and coal-fired power plants at high temperatures (e.g., 140 – 200 °C) under presence of acid gases, owing to its excellent chemical, thermal, and mechanical properties. In general, though the service life of a PPS filter can reach several years, the degradation and deterioration of its mechanical and chemical properties progresses gradually throughout the lifetime of the filter. Oxidation and acid-base corrosion is thought to be the main factors causing the degradation of PPS filters.

Therefore, in this study, the durability of the PPS fabric filter media toward NO2 gas was examined in detail with a continuous-flow type exposure method which is specified in ISO16891:2016.

Moreover, we also suggest an empirical model to estimate the change in the degradation conversion of PPS by NO2 gas and the tensile strength of PPS filter media...

Modelling of the mechanical aging behaviour of PLA-based nonwovens and monofilaments under filter application-relevant conditions

C. Schippers, L. Tsarkova, Deutsches Textilforschungszentrum Nord-West gGmbH (DTNW); J. S. Gutmann, University Duisburg-Essen (UDE); L. Sinowzik*, R. Taubner, Saxon Textile Research Institute (STFI), Germany

Nonwovens and felts from synthetic fibers (polyester, polypropylene) or from glass fibers are the mostly used filter media in air filtration. These mterials offer high efficiency, long service life and a good price-performance ratio. However the modern growing trend to replacem petroleum-based fibers with bio-based and bio-degradable polymers dictates a new challenge for researchers, filter developers and manufatures. The research aims presented here at exploring PLA fibers as an alternative material for applications in air filtration. Particular focus is made on the characterisation of the mechanical properties of PLA under aging conditions, which are relevant for the applications as filter media. On the testing the filtration characteristics of the PLA nonwovens depend on the textile parameters as well as on the quantification of the biodegrabiity of the PLA-based materials...

Experimental study on the preparation of ceramic fiber filter element for hot gas filtration

L. Miao*, Z. Ji, X. Wu, Z. Liu, J. Lu, L. Cong, China University of Petroleum, China

In order to meet process requirements or environmental requirements, dust particles in various process gases and flue gases discharged into the atmosphere usually need to be separated directly under high temperature conditions.

High-temperature ceramic fiber filter element can meet the corresponding filtration performance requirements, and has good thermal stability, chemical stability, thermal shock resistance, fracture toughness and light weight. Therefore, it is one of the ideal hot gas filter media.

The work presents a study on the preparation of ceramic fiber filter element, aiming to improve the overall performance of the filter element, so that it can be better applied in the high-temperature gas-solid separation field...

Production and characterization of filter media obtained by electrospinning for applications in air filtration

D.P.F. Bonfim, V.G. Guerra, M.L. Aguiar*, Federal University of São Carlos, Brazil

Filtration process using fibrous filter media is widely used for the removal of particulate material from a stream of air because these have simplicity of use, low cost and can achieve high collection efficiency, however, the study is scarce when referring to filtration of nanoparticles. Moreover, the emergence of new materials with excellent chemical properties further favored the development of filtration technology, combined with the progress of the field of materials science and technology. New filter media producing technologies have emerged to achieve high particles collection efficiencies with low pressure drop as filters with nanofibers. The electrospinning process is the most used for the production of nanofibers and is distinguished from the other production processes by the versatility of processing different polymers, ability to control diameter, morphology, orientation and fiber structure. This method use electrostatic force to obtain fibers with high contact surface compared with those produced by other methods. One of the challenges to produce these filter media is the adjustment and control of several parameters which has influence on nanofiber production such as: polymer concentration, solvent ratio, collection time, tip to collector distance and the applied voltage. The polymer used was polyethylene terephthalate from post-consumer PET bottles in different solvent systems and concentrations. Such polymer has been outstanding owing to its mechanical properties favorable to the filtration tests since it guarantees adequate resistance for use in diverse applications, for both micro and nanofiltration. After the production of fibrous filter media, they were physically characterized (permeability, porosity, fiber diameter distribution), and the collection efficiencies..

Powder sampling with a pressure port of differential pressure gauge on the high pressure natural gas filter

X. Song*, X. Wu, C. Chang, S. Liu, D. Wang, Z. Ji, China University of Petroleum, China

Operating efficiency assessments of high-pressure natural gas filters are significant for the protection of pipelines and equipment. The conventional particulate measurement method setting a new isoaxial sampling nozzle in high-pressure natural gas pipelines will bring a safety challenge due to pipeline stress change. The work presents a study on the performance of powder sampling using pressure port for differential pressure gauges in an effort to provide a safe and convenient solution for the efficiency assessment of high-pressure natural gas filter.

The performance of powder sampling efficiency of the pressure port at various gas velocities and sampling velocities was characterized in...

Development and performance test of MIL-88 based filter structure using electrophoretic deposition

J.S. Lee*, J.H. Lee, S.H. Lim, Kookmin University, Republic of Korea

An indoor air quality (IAQ) monitoring has been increasing area of interest, because there are many reports of the harmful volatile organic compounds (VOCs) occurred in the house and building. So, development of air purifiers and filters for removing them is required.

In this study, filter structure was developed to adsorb and remove harmful indoor VOCs using metal organic framework embedded nickel foam fabricated by electrophoretic deposition. To confirm the adsorption, removal performance of VOCs, a filter chamber module including a UV module was developed and through the PID sensor, the excellent performance of adsorption and removal of the fabricated filter structure was confirmed...

Macro-scale simulation of fibrous liquid aerosol filters

J. Niessner*, A. Baumann, D. Hoch, Heilbronn University of Applied Sciences, Germany

Today, liquid aerosols are produced in many industrial processes like machining, manufacturing of catalysts or in pneumatic compressors. While the harmfulness of fine dust aerosols is well known the equally dangerous liquid aerosols (mist) receive less attention. In order to be prepared for future legal regulations we develop efficient mist filters with less energy consumption.

In our research, we couple micro-scale simulations of two-phase flow in a fibrous porous medium with macro-scale simulations to develop efficient filters for a stationary (oil mist separator) and a mobile (pneumatic truck compressor system) application. Because the computational effort to simulate mist deposition in a whole filter on the micro-scale would be much too high, on the macro-scale, the information of the micro-scale is adopted and the whole filter is considered as porous continuum. In other words, the output of the micro-scale becomes the input of the macro-scale. Specifically, parameters like porosity, intrinsic permeability as well as relative permeability - and capillary pressure – saturation relationship determined from micro-scale simulations are used as input to the macro-scale to simulate the filtration process on the domain of the whole filter. Furthermore, a source term of the liquid (oil) phase is derived from micro-scale simulations which may depend on parameters such as velocity and initial saturation. Thanks to this multi-scale coupling, it is possible to predict the pressure drop and the separation efficiency of a filter and figure out the factors to optimize these two properties.

Furthermore, different parameterizations of the capillary pressure – and the relative permeability - saturationships (e.g. Brooks & Corey and Van Genuchten) are compared. We also present the validation of our simulations by comparing both pressure drop and separation efficiency to measurement results....

Micro-scale simulation of fibrous liquid aerosol filters

D. Hoch*, A. Baumann, J. Niessner, Heilbronn University of Applied Sciences, Germany

Today aerosols are produced in many industrial processes like machining, manufacturing of catalysts or in pneumatic compressors. While the harmfulness of fine dust aerosols is well known the equally dangerous liquid aerosols (mist) receive less attention. In order to be prepared for future legal regulations we develop efficient mist filters with less energy consumption.

We present first results of micro-scale simulations of mist deposition on fibrous structures. In our framework, the fibrous structure is obtained from µCT scans. Micro-scale simulations provide information on fractional efficiency as well as parameters and constitutive relationships for macro-scale simulation used to investigate pressure drop. Therefore, the micro-scale simulation is closely linked to the macro-scale simulation.

The aim is to develop fibrous mist filters with less energy consumption (reduced pressure drop) and increased fractional efficiency compared to existing filters...


L8 - Short Oral Presentations

Day: 23 October 2019
Time: 14:45 - 16:00 h
Room 1A

Session Chair:
Prof. Wilhelm Höflinger

Characterization and Simulation of Porous Structures

Combined porous mesh metals for filters and capillary fencing devices

V. A. Devisilov*, Yu. M. Novikov, V.A. Bol'shakov, Bauman Moscow State Technical University, Russia

The paper is concerned with the essence and design-technological features of products from new types of porous mesh metals (PSM), made on the basis of a combination of various permeable and impermeable metallic materials interconnected by hot rolling in the vacuum. To create new materials using a combination of different types of metal grids. Therefore, the materials received the name - combined porous mesh metals (CPMM).

The author emphasizes the ideas that the technological problem is to create reliable products with predictable strength, filtration and structural characteristics. The technology of manufacturing products from CPMM is complex and includes a large number of technological operations, which are divided into operations for the manufacture of a material and an operation for manufacturing from it a finished product of the required purpose. Production of the material includes several operations for preparing the initial metal grids (washing, degreasing, marking, assembling the grid package) and complex technological operations for manufacturing the material, which consist in connecting the grids and embedded materials between themselves (vacuuming, heating to a predetermined temperature, rolling the grid package in vacuum and in hot condition, etc.). Each of the technological operations of manufacturing the material must be carried out in rigid ranges of modes - temperature, the degree of compression of the package, etc. A slight deviation from the mode leads to a marriage or a significant deviation from the specified parameters. A difficult problem is the interconnection of metallic grids of various types (differing in thickness, wire diameter, etc.), as well as solid metallic mortgage elements necessary for the formation of products from the material obtained. Because of numerous experiments and experiments, it was possible to achieve success and develop the technology for manufacturing the material CPMM.

The developed material and products from it are introduced at the enterprises of those industries that require highly reliable, efficient, with specified functional parameters of the construction of permeable materials.

A new filter phase separator (FPS) for the fuel tank (FT) of a space product has been created...

Geometrical model of the porous structure of the permeable material and the new experimental method of determinig its structural characteristics

V. A. Devisilov*, A.L. Sintsov, E. Yu. Sharai, Bauman Moscow State Technical University, Russia

In this paper, the author analyzed many of the geometric models of the porous medium used in analytical calculations. The analysis showed that the geometric structure, which summarizes the structural parameters that change along the axis of the capillary, into a single whole, is absent. In many situations, changes in these characteristics across the thickness of the porous element are not considered. The assumption of the constancy of structural parameters in many cases leads to difficulties in the development of porous models. This leads to the usefulness of formulating a new geometric model of a porous structure, which is devoid of the above-mentioned disadvantage. The author proposes a new geometric model of a porous structure, which has the form of a porous matrix consisting of...

Characterization of Porous Materials to Meet Regulatory Demands

Addressing liquid filtration regulatory complexity with HACCP

F. Lybrand*, C. Rich, T. Vest, Hollingsworth and Vose Company, USA

Demand for porous materials used in liquid filtration continues to grow. Pleated cartridges treat fluid streams utilizing many materials to achieve the optimal combination of efficiency, life and flux. With growth in demand comes growth in regulatory complexity. At the wellhead, waste water can be discharged – but determining the appropriate standards to follow is difficult. Municipalities can follow direct-to-potable reuse (“DPR”) guidance – but these are new, complex rules. Producers of food, beverages and pharmaceuticals can use many different liquid quality standards on a single product. These diverse demands are made more complex when the quality of porous materials enables the safety of downstream processes and product. Adopting a common, systematic approach to these questions lowers the cost of compliance and improves the performance of the entire filtration industry.

H&V has adopted Hazard Analysis Critical Control Point (“HACCP” – pronounced ‘Hass-sip’) as its quality management system and business process for analyzing product safety, product suitability, and plant capability in the regulated end markets which dominate liquid filtration. Creating a HACCP plan for products used in liquid filtration gives porous material producers and users a mutual framework to make statements about many questions that are crucial to end customers and regulators, including...

Depth Filtration and Adsorption

Metal porous filter development using additive manufacturing

N. Burns*, D. Travis, L. Geekie, A. Molyneux, Croft Additive Manufacturing Ltd; M. Burns, Croft Filters Ltd, UK

Metal foam and porous metal filters are formed using different manufacturing processes and are permeable for gaseous and liquid media. Industrial metal foams have a high strength and low weight with a large internal surface area and good thermal conductivity and are utilised by heat and automotive industries. Metal foams have a wide range of porosity and pore sizes.

Porous metal material formed from base metal and salt process can have a close range of pore sizes. Sintered metal porous filters are formed from metal spheres, usually of similar size, and fused together, which form regular interstitial spaces and thus have a regular ‘pore size and porosity.

Selective Laser Melting (SLM) Additive Manufacturing (AM) technology manufactures components layer by layer which delivers design freedom to produce complex geometry components. Another level of complexity that can be achieved in powder bed fusion AM systems is that of variable porosity. SLM AM utilises metallic powder of different sizes which are melted by the laser. By controlling the laser settings SLM AM can produce components with different levels of porosity.

In this study we have investigated the viability for AM technology to produce depth filters that have different aperture sizes through increasing and decreasing porosity in the filter in a metal foam format and a porous metal format...

Design of a multi-purpose fuel filter sytem to better understand the challenges of biodiesel filtration

B. Csontos*, H. Bernemyr, A. Christiansen Erlandsson, KTH Royal Institute of Technologies; M. Pach, H. Hittig, Scania CV AB, Sweden

Heavy duty transportation is a growing area where the reduction of fossil fuels would be highly beneficial for the environment. A feasible way in the truck industry to achieve lower greenhouse gas emissions is the use of renewable fuels. Since the most common propulsion system in heavy duty vehicles are diesel engines, suitable renewable fuels include biodiesel, also known as fatty acid methyl ester (FAME). Although there are regulations for biodiesel such as ASTM D6751 and EN 14214, due to known drawbacks such as its susceptibility to degradation or its bad cold flow properties, using biodiesel in trucks could still cause unwanted effects to the filter system. Furthermore, these standards are not applicable in every part of the world. Thus investigation of the contaminants which could create soft deposits and plug filters is required. From previous experiments it is known that soft deposits mainly consist of fuel degradation products such as metal carboxylates, or impurities from the biodiesel production. The aim of the work is to present a filter system where the interaction of deposits with the filter materials and with each other can be studied...

A probabilistic-statistical model of change in particle size distribution in fine filters

A.N. Grechushkin*, V.A. Lvov, Bauman Moscow State Technical University, Russia

Fine filters are widely used to remove dispersed contaminants in liquid purification systems. In some cases, it is not enough to calculate change in the mass concentration of contaminants, it is also necessary to know the change in particle size distribution of the dispersed phase, as well as to determine the rated filter fineness. The change in the mass concentration of the dispersed phase during filtration can be calculated with the sufficient reliability using empirical methods. In the same time, the change in the particle size distribution is often evaluated based on the operating experience with similar equipment. In practice it can lead to significant errors and sometimes to emergency situations.

The filtration of suspension is a continuous dynamic process that includes retaining particles in pores and carrying away the particles retained previously by flow hydrodynamic forces. Moreover, the influence of the latter increases as the pores are clogged with dispersed phase particles. When adhesion and cohesion forces have the same values, the membrane layer stops to retain particles of the dispersed phase. The change in concentration of dispersed phase particles can be represented as the transition of particles from...

Adsorption of humic acid from aqueous solution onto Fe3O4 magnetite: Effect of temperature

M.A. Zulfikar*, A. Rizqi Utami, M. Yudhistira Azis, H. Setiyanto, Institut Teknologi Bandung, Indonesia

Humic substance, which are present in peat water, adversely affect water quality in several ways: causing undesirable color and taste, binding with heavy metals and biocides and reacting with chlorine during water treatment to produce trihalomethanes, which affect human health very seriously and can even cause cancer. Therefore, the presence of humic acid in peat water has been a great concern and measures have to be taken to minimize the presence of humic acid in water resources. In this study, the sorption of humic acid from aqueous solution onto Fe3O4 magnetite under the influence of temperature has been investigated...


L9 - Short Oral Presentations II

Day: 23 October 2019
Time: 14:45 - 16:00 h
Room 1B

Session Chair:
Dr. Harald Anlauf

Backwashing Filters

HETA smart filtration 4.0

H. Hensel*, HETA Verfahrenstechnik GmbH, Germany

The aim was to develop a filtration system which is able to control the operating parameters and to optimize them automatically. This then should result in an improved, cost effective and environmentally friendly use of filtration equipment, raw material charge, energy and other resources! Use of the newly developed system should be possible for both new systems and inventory.

Through their lengthy professional experience of automated filtration processes, HETA Verfahrenstechnik GmbH already had the needed process engineering hardware know-how. This was then supplemented through intensive development work to provide the required control and software solutions- at Industry 4.0 level.

From test run directly into service: The promise of the HETA 4.0 automatic filter controlling system has already been proven in practical day-to-day service. Together with one of the leading chemical companies a test run scenario was developed. The test results have been so excellent that the customer immediately decided to incorporate the HETA 4.0 system in their standard production environment!

Meanwhile HETA applied for and been officially granted registered design status. Additionally the patent for HETA 4.0 is pending!

Self Cleaning Filters

Filtering of high solids concentration media using complex powerful to the flow

E.Y. Sharai*, V.A. Devisilov, Bauman Moscow State Technical University, Russia

The paper is concerned that the intensification and efficiency of filtration processes for high solids concentration media are of widespread interest in many industries, such as oil production, oil refining, chemical, medical, and food. One of the reasons that impede filtration may be a high viscosity of the raw liquid. It is known that the filtration rate is inversely proportional to the viscosity; therefore, filtering viscous liquids will occur much slower. In addition, filtering high solids concentration media is associated with high costs for creating the driving force of the process, fast clogging of the pores of the filter material, the need for frequent regeneration of the filter material. Many high solids concentration media, such as mineral oils, polymer solutions and melts, highly polluted waters, tend to overgrow the flow area of ​​the pore channel and, as a result, change their hydraulic characteristics due to the presence of helices and molecules of high molecular media, which makes filter regeneration difficult. Therefore, there is a need to replace the filter material with a new one. It is possible to intensify the filtration process by conducting preliminary preparation of the suspension, for example, by increasing the temperature of the medium or by decreasing the viscosity of the suspension by adding an appropriate solvent. In many technological processes, such methods are unacceptable. Relevant is the development and study of devices that allow you to increase the life of the filter material before regeneration, reduce energy costs to create the required pressure drop while maintaining the compactness of the device and the required cleaning fineness. The authors propose a method of filtering high solids concentration media and highly polluted liquids in...

Simulation of solid particle separation in self-cleaning filter with dynamic filtration

E. Y. Sharai*, V.A. Devisilov, Bauman Moscow State Technical University, Russia

Paper presents numerical analysis of solid particles separation from the liquid by the filter with rotating cylindrical filtering baffle. This filter, with the property of self-cleaning, is effective for separating both viscous and highly viscous media. А centrifugal force field appears in the working channel of the filter due to moving of flow being cleaned from outside to inside of rotating cylindrical baffle (opposite to the direction implemented with centrifugal filtration). Under the effect of centrifugal forces, solid particles with density greater than the density of the liquid tend to move in the opposite direction of the filtering surface and do not settle on it. Small particles and particles with the density less than the density of the liquid are trapped by filtering baffle.

Flow structures and particles separation was simulated using the CFD software tool (ANSYS CFX). The computational model is based on the Navier-Stokes equations, taking into account the Euler-Euler multiphase model for calculating the volume fraction of phases, and on the multiphase Lagrange model for finding particle trajectories. The simulation showed that separation efficiency can be significantly reduced due to the presence of turbulence and vortex formation in the manner of Gepler-Taylor vortices. The simulation also showed that...

Magnetic Separation

Applied colloidal aggregation: Separation of fine polymer particles from dilute suspensions by magnetic seeded filtration (Microplastics)

F. Rhein*, H. Nirschl, Karlsruhe Institute of Technology (KIT), Germany

Microplastics are nowadays a highly discussed topic: Whether through the decomposition of larger plastic waste or direct usage on a small particle scale, microplastics find their way into the natural ecosystem with still not fully understood consequences. This work investigates the separation of such contamination by magnetic seeded filtration on a laboratory scale and thus discusses an application example for the often theory-focused colloidal aggregation process. Magnetic seeded filtration consists of two steps: Firstly, fine paramagnetic particles are agglomerated with magnetic particles and secondly, these hetero-agglomerates are removed from the suspension by high gradient magnetic separation.

In the scope of this work, it could be shown that it is possible to reach high separation efficiencies of up to 10-2 vol%. Furthermore, a thorough parameter study identified the electrostatic interaction to be of dominating importance: Especially the pH value regulating the surface charge of the particles effects the process results dramatically. However, even with non-optimal pH setting resulting in repulsive surface charges, an agglomeration could be forced by the adjustment of the ionic strength. In addition, this work gives insight into the agglomeration kinetics: Time dependent separation efficiencies are measured and were able to be described by simplifying mathematical models. Thus, the process is opened up for further optimization, as process time and result can be balanced in a profound manner.

This presentation gives insight into the applicability of magnetic seeded filtration in general and offers operational guidelines that improve process results. Furthermore, the obstacles and major concerns for a large-scale implementation are discussed...

Investigation of magnetic separation for the cleaning of automatic transmission fluids

P. Rack*, M. Dedering, D. Feggeler, IBS-Filtran GmbH; R. Kirsch, Fraunhofer Institute for Industrial Mathematics (ITWM); E. von Lavante, University Duisburg-Essen (UDE), Germany

The growing demands on filter elements for automatic transmission fluids in terms of filter lifetime (longer service intervals), cleanliness level of the oil and lower pressure drop represent a great challenge for product designers. In order to ensure good performance of the filters at the widest possible range of operating conditions (e.g. cold start vs. high oil temperature) and facing more restrictive installation space specifications, intense research and development is required for product innovation and optimization.

The fact that the wear in automatic transmissions contains ferromagnetic shares suggests magnetic separation as a way to support the cleaning of the oil by the filter media. However, despite the constraints on the installation space mentioned, this introduces new degrees of freedom for the filter element design. Therefore, a purely empirical approach for the optimization of the device would lead to rather long and costly development cycles. On the other hand, customized simulation tools have proven their worth in accelerating the development of optimized filter elements.

The present work is devoted to the investigation of magnetic separation for cleaning automatic transmission fluids. The experimental methods used for the study and the algorithmic approach for the coupled simulation of fluid flow and particle transport are presented are illustrated by examples and the results are discussed...

Electrochemical Water Treatment

Electrodegradation of methylene blue using Ce(IV) mediated electrochemical oxidation: Effects of supporting electrolyte, potential oxidation and degradation time

H. Setiyanto*, F. M. Sari, M. A. Zulfikar, Bandung Institute of Technology; V. Saraswaty, Indonesian Institute of Sciences; N. Mufti, State University of Malang, Indonesia

Mediated Electrochemical Oxidation (MEO) is one of electrochemical method are widely used to degrade organic pollutans from waters. Dyes represents one of the problematic group. We have studied the degradation of methylene blue (MB) using MEO methode by batch system with Ce (IV) as mediator. Ce (IV) as mediator was made electrochemically from the oxidation of Ce (III). Ce (IV) can degrade textile dye waste by oxidizing them into simpler products so that the danger level is reduced. Voltammetric studies have been performed by the cyclic voltammetric technique using carbon paste electrodes as working electrodes, Ag/AgCl as comparative electrodes and platinum wires as auxiliary electrodes. The results show the potential of oxidation of Ce (III)/Ce(IV) and methylene blue at 1.25 volts and 0.27 volts. The study of methylene blue degradation was performed by electrolysis using platinum wire as anode and cathode. The total degradation...

Separation of crude oil from crude oil contaminated water using biowaste-waste polythene composite

K.A. Ibe*, E.E. Elemike, B.C. Okoro, Federal University of Petroleum Resources Effurun, Nigeria

Water is hydro part of the earth (hydrosphere) where a lot of activities that are of biological and economic significance to life take place. This exposes water to pollution by different pollutants such as crude oil, heavy metals and others. There are numerous methods and technologies for separating and removing these pollutants, but they are quite expensive.

A very cheap method of separating these pollutants especially crude oil involved the use of bio-waste (saw dust & egg shell) and waste high density polyethylene (HDPE) bag composite was explored. The composite was produced by extrusion of the high density polyethylene waste reinforced with saw dust and eggshells combined in different ratios using Jombo Extruder Mark 35mm at 250°C, and collected in receiving molds which were allowed to cool before scaling out. The prepared composites were immersed in simulated crude oil spill troughs containing 750g of crude oil of API 40.5 each. The highest percentage of crude oil adsorbed by one of the composites was about 37.0% while the least was about 25.2%. The highest values of crude oil separated from the simulated spill trough was appreciable but more so the preparation of the composites from the constituents used serves as a channel for recycling of wastes.


M6 - Short Oral Presentations

Day: 23 October 2019
Time: 14:45 - 16:00 h
Room 2

Session Chair:
Dr. Thomas Peters

Effect of ethanol concentration on filter cake characteristics in microfiltration of yeast suspension

N. Katagiri*, K. Tomimatsu, E. Iritani, Nagoya University, Japan

Microfiltration is widely used to remove microbial cells from the fermentation broth in the downstream processing of biotechnological products. Since the filtration behaviors are strongly affected by the properties of the microbial cell cake formed on the surface of the membrane, knowledge of the cake structure provides valuable information for the design and operation of filter equipment. In the alcohol fermentation process using a yeast strain, it is considered that cake characteristics are complicated because yeast cells are strongly influenced by external factors such as filtration pressure and alcohol concentration. In this study, we evaluated the membrane filtration properties, especially the cake characteristics, of yeast suspension containing ethanol and investigated the effects of pressure and ethanol concentration on separation of yeast...

Combination of ultrafiltration (UF) and powdered activated carbon (PAC) to remove micropollutants, antibiotic resistant bacteria and phosphorus from wastewater

M. Werner*, MICRODYN-NADIR GmbH, Germany

Nowadays the high usage of pharmaceuticals like antibiotics, analgesics or X-ray contrast agents for human and veterinary treatment leads to increasing concentrations in municipal wastewater and in the aquatic environment.

Apart from micropollutants, the global concern regarding the threat of antibiotic resistant bacteria (ARB) in the environment is growing. Due to a 40 % increase in global consumption of antibiotics over the last decade, combating antibiotic resistances represents a complex challenge.

Municipal and industrial wastewater, which is collected and treated in wastewater treatment plants, harbours various bacteria from environmental, human and animal origins. During the biological treatment process, a removal of micropollutants (up to 50 %) and ARB (up to 2-3 log levels) takes place. [3, 4] Despite the mentioned removal capability of conventional wastewater treatment plants, a significant amount of such substances still enters the aquatic environment by discharging treated wastewater into surface water bodies. Therefore, wastewater treatment plants play a major role regarding the removal, separation and distribution of micropollutants and ARB into receiving waterbodies.

To optimize wastewater treatment plants for the removal of micropollutants (>80 %), additional treatment processes (so called fourth treatment steps) have been implemented in several plants in Central Europe. [5, 6, 7] With currently established treatment technologies like Ozonation with subsequent sand filtration, granulated activated carbon filtration and powdered activated carbon filtration followed by sand filtration, an efficient reduction of micropollutants can be achieved. [5, 8, 9] Nevertheless, a complete separation of ARB cannot be guaranteed with these technologies.

This is where the “BIO-CEL® Activated Carbon process”, a combination of Powdered Activated Carbon (PAC) usage with submerged ultrafiltration membrane technology, developed by MICRODYN-NADIR steps in. This hybrid process takes advantage of established methods (adsorption and filtration) and provides an option to meet higher effluent requirements of treatment plants e.g. the complete separation of bacteria and germs.

Pilot plants with the BIO-CEL Activated Carbon process have been operational in North Rhine Westphalia and Hesse, Germany since 2016. An important partner is the Emschergenossenschaft and Lippeverband (EGLV), the largest wastewater management company and operator of wastewater treatment plants in Germany, which provided sites for pilot testing.

The BIO-CEL Activated Carbon process is...

Microsand cross flow filtration in cooling towers water circuit – a sustainable approach for HVAC systems

S. Roel Backes*, Evoqua Water Technologies GmbH, Germany

Acclimatization of buildings play a vital role on the expected comfort of the population and HVAC system guarantees the temperature control. With the purpose of saving energy, many HVAC systems are coupled to cooling towers, considered one of the most cost-effective cooling technologies for commercial air conditioning and industrial processes by allowing heat laden water to flow into the cooling tower through different panels exposing the heated water to air. Nines & Leed indicates in their essay sustainable operation of HVAC that “cooling towers are a common and critical component to most commercial, institutional, and industrial facilities and can represent up to 30 percent of a building's overall energy budget, and 50 percent of the water usage”:

And where does filtration come in this picture?

Removal of suspended solids and other contaminants contribute dramatically to the requirements of periodically adding of fresh water to the system “blowdown” because filtration reduces the concentration of pollutants. Eneref Institute published a report end 2018 examine the benefits of cross-flow microsand filtration based on own research, which found the technology to be a reliable, efficient and environmentally friendly means of eliminating submicron particulate in HVAC cooling tower and process cooling applications. According to the Eneref Institute cross-flow microsand filtration (CMF), is used to capture microscopic and even submicron particles. Traditional deep-bed multimedia, or sand, filters typically capture particles of 20 microns and above. While MMF can remove up to 90% of contaminant particles by weight, they leave unchecked all fine particles—the particulates that are most responsible for the fouling that supports Legionella and system inefficiency (95 % of particulates are less than 5 microns....

...A better understanding of water filtration systems will help building operators reduce the quantity of toxic chemicals discharged into the environment, increase both energy and water efficiency, and limit the growth opportunity for pathogens....

Application of antifouling filter media based on nanofibres in liquid filtration

I. Vincent*, D. Kimmer, L. Lovecka, M. Kovarova, L. Musilova, D. Vesela, Tomas Bata University , Czech Republic

Preparation of homogeneous modified nanofiber structures with the desired morphology1 and properties by electrospinning process and consequent exploitations in liquid filtration2,3 are presented.

Nanostructured materials applied for liquid filtration require additional filter reinforcing, rather poor mechanical properties of nanofibers being the reason. One of the possible reinforcing way can be insertion of nanofiber layer between two cellulosic filtration materials. Combination of cellulose fibers with nanononwoven textile (nNT) based on polymeric nanofibers in board filters results in excellent improvement of bacteria Serratia Marcescens removal measured in accordance with ASTM F838-05. Used bacteria were in sizes 0,5-0,8 × 0,9-2,0 µm. Proper anchorage of antifouling agent into filtration material is very important from the toxicity aspects and ecological point of view. Changes of antibacterial activity in time has been demonstrated on modified nNTs and origin ones. It has been proved the positive influence of silver particles anchored on nanofiber surface on flux improvement because of...

Integration of functional transmembrane proteins into a membrane for nanofiltration

M. Schwieters*, M. Mathieu, U. Glebe, A. Böker, Fraunhofer Institute for Applied Polymer Research IAP, Germany

Membrane processes for purification are of great industrial interest as they are easy to scale up and may be tailored to individual requirements. Indeed, membranes for highly specific applications are commercial standard, including those with pore sizes in the lower nanometer range. However, to enable filtration with considerable flux, operating nanofiltration membranes usually requires high transmembrane pressures. Current industrial nanofiltration is thus an energy- and cost-intensive process. To overcome this limitation, a new generation of ultrathin, bioinspired nanofiltration membranes is being investigated at Fraunhofer IAP. The new membranes are less than 10 nm thick, which allows for low-pressure nanofiltration and moreover makes our membranes interesting candidates to be applied in biomedical microdevices. The membranes consist of modified variants of the ß‑barrel-shaped channel protein FhuA acting as monodisperse filter pores. FhuA appears in nature as an iron transport protein in bacterial membranes of Escherischia coli (E. coli). In addition to its robust channel structure, the interior of the nanopores may be engineered to fullfil various separation requirements, e.g. size and chirality.

We pursue several approaches for the integration of FhuA into membranes...

Measuring methods for nano filtration membranes and filter materials

X. Puntigam, M. Kalmutzki, P. Pavlov, B. Arlt*, Anton Paar Germany GmbH, Germany

With Anton Paar instruments the surfaces of filters, membranes, coatings, thin films, and functionalized layers can be investigated on the macro, micro, and nano scale. Users can determine parameters including hardness and elastic modulus to creep, fatigue, stress-strain, wear rate, lubrication, and zeta potential, specific surface area and pore sizes among others.

Researchers concerned with the development and production of new materials as well as those concerned with the modification and optimization of material properties and production processes take advantage of different technologies, such as:

  • Indentation testing
  • Scratch testing
  • Tribometry
  • Coating thickness testing
  • Atomic force microscopy (AFM)
  • Surface charge analysis
  • Specific Surface area
  • Small-angle X-ray scattering (SAXS) | Grazing-incidence SAXS (GISAXS)
  • Pore sizes and their distribution

This overview presentation will shed light on exemplarily materials such as polymeric membranes and filters for waste water treatment.

Effect of spacer orientation on the performance of direct contact membrane distillation

Y. Taamneh*, Jordan University of Science and Technology, Jordan

The effect of the presence of spacers and their orientation on the flow pattern and heat transfer enhancement for a commercial direct contact membrane distillation module was conducted. In this research, both experimental and computational fluid dynamics (CFD) simulations are carried out when the two sets of spacer filaments are oriented at an angle of 45 o to the channel axis and also when the top filaments are oriented at an angle of 30o, 45o, 62o and 90o while the bottom filaments are being parallel to the direction of flow. Besides predicting the Nusselt number and the total drag coefficient, the simulated results allow deeper understanding of the role of spacer presence and its filaments orientation in permeate flux augmentation . It is found that the degree of enhancement in heat and mass transfer depends on filaments orientation of spacers. The simulated results show that...

Analytical photo-centrifugal filtration (ACF): Membrane resistance and filterability

S. Boldt, D. Lerche*, LUM GmbH, Germany; M. Loginov, INRAE - National Institute for Agriculture, Food, and Environment, France

Filtration has broad applications in academic and industrial research as well as in product development. In general, filter-nutsch or filter-pressure approaches are applied. Recently, an analytical photo-centrifugal set up was introduced as a new laboratory technique to characterize membranes and filterability of samples (suspensions, protein solutions, extracts, etc.).

Analytical centrifugal filtration (ACF) is based on continuous in-situ measurement of spatial resolved light transmission through a centrifugal filtration cell monitoring the volume decrease of the sample (top) or the filtrate increase (bottom) by STEP-Technology®). Centrifugal acceleration for dispersion separation can be simply set by programming rotor revolutions from 200 – 5000 rpm. Up to 12 samples (0,2 ml -1 ml) can be analyzed simultaneously. Different procedures can be applied to characterize membrane resistance and filterability of various sample types (diluted or concentrated macromolecule solutions or suspensions).

In this paper the basic measuring technique of ACF, the newly designed centrifugal filtration cells are described and corresponding quantitative analysis discussed...


F8 - Micro and Nanofiltration Media

Day: 23 October 2019
Time: 16:45 - 18:00 h
Room 2

Session Chair:
Dr. Christine Sun

Some aspects of application nanostructured filter media in air and water filtration

D. Kimmer*, I. Vincent, L. Lovecka, M. Kovarova, L. Musilova, Tomas Bata University ; J. Ondracek, Institute of Chemical Process Fundamentals of the CAS, v. v. i., Czech Republic

Procedures of preparation homogeneous nanofiber structures of the desired morphology1 and properties by electrospinning process and consequent exploitations in air and liquid filtration2 are presented.

Nanostructures applied in air filtration possess excellent filtration efficiency first of all in separation of ultrafine particles. Presented and compared have been the filtration properties of electrospun materials with homogenous structure in the whole manufactured width 140 cm. The minimum pressure drops of these materials varied from 6 to 8 Pa only. Values of filtration efficiency are measured in accordance with requests of EN 1822 for elimination of ultrafine particles in sizes 20 through 400 nm

To evaluate the influence of chemical composition of nanofibers on filtration efficiency in MPPS (maximum penetrating particle size), the nanostructure based on polyvinylidene fluoride, polyurethane, polylactide acid and polyamide 6 have been compared...

Low-cost porous ceramic filters for potential microfiltration and ultrafiltration applications

J.-H. Ha*, J. Lee, I.-H. Song, Korea Institute of Materials Science (KIMS), Republic of Korea

Recently porous ceramic filters have become a subject of special interest due to their outstanding thermal and chemical stability. To alleviate the manufacturing cost issues of porous ceramic filters, recent research is focused on the utilization of low cost raw materials.

In this study, we introduced porous ceramic filters prepared from low cost raw materials such as diatomite, kaolin, pyrophyllite, and silicon carbide. And we report the results of our efforts to determine whether we could prepare a low-cost ceramic filter that could control the average pore size, the largest pore size, the flexural strength and the air/water permeability effectively. The pore characteristics of the specimens were studied by scanning electron micrography, mercury porosimetry, capillary flow porosimetry, and a dead-end microfiltration system with particle counters...

Development of microfiltration membranes of biodegradable biomass plastics with the aid of surfactants and their application to depth filtration

T. Tanaka*, H. Minbu, A. Ochiai, M. Taniguchi, Niigata University, Japan

In the near future filter media should also be environmentally benign to achieve Sustainable Development Goals (SDGs). We have been developing microfiltration membranes of biodegradable biomass plastics by using thermally and/or nonsolvent-induced phase separation methods [J. Membr. Sci. 238 (2004) 65; Desalin. Water. Treat. 17 (2010) 176; J. Membr. Sci. 396 (2012) 101; J. Membr. Sci. 479 (2015) 85]. The biodegradable membranes are compostable after filtration to reduce the industrial wastes, and the use of biomass plastics will reduce that of the fossil resources.

In this paper we showed the development of microfiltration membranes of poly(L-lactic acid) (PLLA), one of the major biodegradable biomass plastics, with the aid of surfactants. The membranes were applied to depth filtration to avoid the formation of dense filter cake...


G10 - Filter Test Systems II

Day: 23 October 2019
Time: 16:45 - 18:00 h
Room 4A

Session Chair:
Prof. Achim Dittler

Investigation of regeneration stability of pulse-jet regenerated filter media under laboratory test conditions

P. Spanring, N.A. Nowak, T. Laminger*, G. Mauschitz, Vienna University of Technology, Austria

The usage of cleanable filter media with pulse-jet regeneration is widely used in industry. Dust becomes separated at the surface of the filter medium and by the forming dust cake. When a maximum pressure drop is reached a pulse-jet regeneration is triggered and the dust cake is detached from the filter medium surface. The remaining dust at the filter surface or within the filter medium leads to an increase of the filter medium air resistance.

The regeneration efficiency of the dust loaded filter medium will influence the following filtration cycle. Remaining dust leads to a faster rise of the pressure drop, respectively the filtration cycle duration becomes lower. Depending on various mechanisms of filter clogging the residual pressure drop will nearly never be constant, even after hundreds or thousands of filtration and regeneration cycles. Therefore, the life time of a filter media is either determined by reaching a maximum residual pressure drop or a minimum cycle duration time limit.

Still there is a need of quantification of stable, respectively unstable, filter operations. Therefore, in this work a detailed investigation of the fluctuations of residual pressure drop and cycle duration is done. Thereby, the frequency and intensity of arising fluctuations is used for the stability assessment. Lab-scale filter tests with various filter media (e.g. membranes, needle felts) under different constant operation conditions and cleaning intensities are tested using a VDI 3926 filter test rig with alumina-oxide test dust (Pural NF, Sasol) are done to obtain data on the evaluation of residual pressure drop and cycle duration. Frequency and intensity of deviation ratios of these parameters are calculated and investigated in order to clarify clogging and regeneration of the dust cake.

HEPA/ULPA filter leak testing for production control using solid PSL (Polystyrene-Latex) aerosol

M. Gahlert*, A. Rudolph, C. Peters, S. Große, Topas GmbH, Germany

HEPA (High Efficiency Particulate Air filter) and ULPA (Ultra Low Penetration Air filter) are typically used to clean up the ventilation air for clean room applications like electronic industry, hospitals and also protection of the environment. For such challenging application which could influence health of people and quality of goods, 100 % control of produced HEPA/ULPA filters has to be carried out to verify/confirm the absence of leaks according to the standard EN1822/ISO29463.

Leak testing each filter leaving the production demands an automated and rapidly measuring solution.

Topas GmbH developed a highly automated filter scanning system which combines flexibility and speed in a suitable way. The system itself adjusts the correct dilution and the aerosol amount as well as the correct aerosol material, according to the filter type properties and runs the highly automated test routine. A unique solution for each customer guarantees continuous development starting with the project and includes practically feedback.

The technical implementation of both, standard requirements and customer requirements, will be described in detail as state of the art in the paper...

Filter testing regarding separation efficiency in terms of airborne fungal spores

B. Führer*, C. Hartl , P. Lukas., G. Ettenberger, OFI Technology & Innovation Ltd.; M. Nachtnebel, J. Rattenberger, ZFE Graz Centre for Electron Microscopy, Austria

Allergenic bioaerosols, such as particles originating from animals, mites, fungal spores or plant pollen are ubiquitous in the air. The removal of allergenic bioaerosols from indoor air by air filtration is of high relevance for allergy sufferers. Currently, air filters are mostly tested with well-defined mineral particles or plasticizer aerosols such as ISO 12103-1 A2 fine dust or DEHS. These standardized test dusts represent the particle size of bioaerosols, but not their shape and physicochemical properties, which play an important role in the separation of small, respirable particles (<10 µm).

As biological particles have a different behaviour compared to non-biological particles it is important for filter design and testing to investigate the interactions between biological dusts and (biofunctional) filters also in terms of optimization. The aim was to develop a standardized method for testing filter media and modules with defined test dust containing fungal spores via a special designed filter test rig. The focus lay on comparison of biological separation efficiency with the separation efficiency of common non-biological test dusts as it is important to know about the biological risk of the particles exposed to the filter and to humans and not only number and size...


G11 - Modelling and Simulation

Day: 23 October 2019
Time: 16:45 - 18:00 h
Room 4B

Session Chair:
Prof. Paolo Tronville

Flow through randomly-oriented fibrous filters

J. Chaudhuri*, K. Boettcher, P. Ehrhard, Technical University Dortmund, Germany

Fibrous filters are often employed to remove dispersed aerosol particles from a gas stream due to low cost, high capture efficiency and low pressure drop. The performance of such a filter medium is judged based on its capture efficiency and its pressure drop characteristics. Estimating these parameters without setting up experimental investigations of each filter medium is beneficial for choosing and developing optimal filters.

In the present study, numerical simulations using ANSYS CFX are used to predict the pressure drop caused due to an air flow through a randomly oriented fibrous filter medium...

The influence of slip flow on filtration simulations on the nano scale

L. Cheng*, S. Linden, A. Wiegmann, Math2Market GmbH, Germany

Nanofibers are attractive to use in air filtration, due to the high surface-to-volume ratio, low flow resistance and enhanced filtration performance. However, the cost of nanofibers and slowing down in production process when using them leads to the desire to use as few nanofibers as possible. We treat such optimization issues by simulating filter media and filtration processes resolving the smallest scale.

The low pressure drop for nanofiber filters is explained with the slip flow effect, which states that in nano regime, the velocity of air at a surface does not vanish in the tangential direction. Since in our modeling, we convert a 3D fiber structure into voxels, applying a wall shear stress on such a staircase shape of the fiber surface is quite a challenge.

Previously, the slip-flow boundary condition could not be implemented directly into voxel-based flow solvers in a satisfactory fashion. In our previous work [1-5] we used two methods, the equivalent shrunk fiber and the equivalent permeable fiber, as workarounds. In the equivalent shrunk fiber method, the fiber is shrunk to make a flow possible in the fiber surface voxels. In the equivalent permeable fiber method, the nanofiber is permeable to make flow pass through it. However, there are limitations and disadvantages to both methods. They require either very high resolution of the structure or a lot of computational efforts to find the appropriate hypothetical permeabilities.

In this new approach, the expression of the slip velocity, which assumes the slip velocity proportional to the shear stress at the surface [6], is now reformulated for a locally quadratic velocity profile instead of the standard linear profile, and reimplemented in our flow solver. The direct simulation of the slip flow is then possible. The validations with analytic solutions are presented.

The influence of slip flow in nanofiber structures then is investigated and the results of flow and filtration simulations are compared with measurements...

Numerical and experimental investigations on loading-dependent particle deposition in electret filter media

M. Kerner*, S. Antonyuk, Technische Universität Kaiserslautern; K. Schmidt, IT for Engineering (it4e) GmbH; S. Schumacher, C. Asbach, Institute of Energy and Environmental Technology e.V. (IUTA), Germany

Electret filter media are commonly used in aerosol filtration to remove particles from gases. They provide a high initial particle removal efficiency combined with a low pressure drop as the fibers of the electret filter media are electrostatically charged. In addition to the mechanical deposition mechanisms (diffusion, impaction and interception), charged particles are deposited by the Coulomb effect and any (charged or uncharged) particles by dielectrophoresis. However, the particle deposition is reduced with increasing exposure time, since already deposited particles can either neutralize or shield the electrostatic charge of the microfibers and thus weaken the above-mentioned electrostatic effects.

In this work the experimental investigations of the loading-dependent particle deposition are performed exposing electret filter media to...


L10 - Centrifugal Sedimentation - Decanter Centrifuges

Day: 23 October 2019
Time: 16:45 - 18:00 h
Room 1A

Session Chair:
Dr. Harald Anlauf

About dynamic modeling and process simulation of solid bowl centrifuges

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

Solid bowl centrifuges such as decanting or tubular centrifuges are widely used in the chemical and pharmaceutical industry, food and biotechnology, minerals processing or wastewater treatment to separate dispersed particles from a continuous liquid phase. The design of those machines is based on simplified stationary black-box models which do not consider the physical behaviour of the separation process as well as the sediment build-up. Thus, the design and scale-up are not possible without countless pilot-scale experiments. However, this is very time consuming and costly. The advantage of dynamic modeling of solid bowl centrifuge is to significantly reduce service life and react quickly to product fluctuations. The resulting process intensification goes hand in hand with increased productivity coupled with reduced energy requirements and overall costs.

This work presents strategies for dynamic modeling of decanting and tubular centrifuges to forecast the separation process and the mechanical dewatering of incompressible and compressible sediments.

Dynamic simulation of mechanical dewatering of compressible cake in decanter centrifuges

P. Menesklou*, M. Gleiß, H. Nirschl, Karlsruhe Institute of Technology (KIT), Germany

Finely dispersed suspensions occur as intermediate or end products in many processes in the chemical, pharmaceutical and minerals processing industry. Continuous solid-bowl decanter centrifuges are frequently used for solid-liquid separation. The mathematical description of the cylindrical and conical parts is necessary in order to be able to predict the solids content profile of finely dispersed cake in decanter centrifuges. The reason for this is the influence of the transport behavior on the residence time of the compressed cake in the apparatus. As a result of the inadequate choice of process conditions, the formed sediment accumulates in the cylindrical part, the transportability of the sediment is influenced negatively and the process may succumb completely.

In this presentation a dynamic model for the simulation of the mechanical dewatering of a finely dispersed product in the conical part of the decanter centrifuge will be discussed...


L11 - Centrifugal Cake Filtration

Day: 23 October 2019
Time: 16:45 - 18:00 h
Room 1B

Session Chair:
Dr. Karsten Keller

The Krauss-Maffei peeler centrifuge with pneumatic cake discharge

G. Grim*, ANDRITZ KMPT GmbH, Germany

Filtration centrifuges typically apply the earth acceleration to discharge the cake downwards after the diverse process steps in the centrifugal field. This is valid for centrifuges with horizontal and with vertical axis. A peeler knife will transfer the cake to a moist powder, which will be conveyed out of the basket. Leaving the basket this powder will fall down to the next process equipment as a dryer or some type of packaging device, like bins or drums. To allow such a gravity powder transfer system, quite substantial pipe diameters are required to avoid blockage of this system.

The biggest disadvantage of the existing technology is that the transportation path from the centrifuge to the dryer is quite sensitive to crust formation and even blocking because an effective transportation force is missing. Often operators must manually interfere and remove product deposits, either inside of the centrifuge or in the downpipe to the dryer or at the inlet valve of the dryer.

In case of discrete batches, the amount of product which is forming the deposits is lost product, which must be removed by dissolving or flushing down by a cleaning in place ( CIP ) procedure before starting the next batch. If the product is very valuable and especially if the batches or campaigns are small, this amount of product might represent an important loss of yield and profit.

In total, the amount of residual product within the centrifuge is typically around 5% of the basket volume. The amount of residual product in the gravity powder transfer system is significantly more, even up to 20% of the basket volume.

ANDRITZ has developed and patented a new peeling and conveying system, which is not requiring any gravity discharge...

Determining the filtration properties of different protein crystals in the centrifugal field using low volume samples

B. Radel*, T.H. Nguyen, H. Nirschl, Karlsruhe Institute of Technology (KIT), Germany

Due to advances in the microbial production of target molecules, product titers after fermentation have increased in recent years. In the case of proteins, such high titers are a challenge for downstream processing. Typically, centrifugation and several chromatography steps separate the target protein from the impurities and the mother liquor. High titers in the mother liquor require large chromatography columns and large amounts of solvents making the downstream process expensive. Additional precautions regarding toxicity and explosive properties may be required when using organic solvents. Therefore, alternative methods such as selective preparative protein crystallization are becoming more and more interesting for the pharmaceutical industry. Another positive aspect of crystalline proteins is a longer shelf life and different drug release properties. After the crystallization step, the protein crystal must be separated from the mother liquor. Dead-end cake filtration is often used for this solid-liquid separation step. Compared to conventional crystals, protein crystals have a lower mechanical stability. Even at low pressures, crystal breakage or abrasion can occur, which worsens the filtration behavior.

In current research Nowotny et al. have modified the amino acid sequence of the enzyme alcohol dehydrogenase from Lactobacillus brevis in order to improve the crystallization properties. Kubiak et al. used cross-linking of lysozyme crystals, which increased the mechanical stability. For cost reasons, the screening of such modifications is typically carried out on a small scale with only a few milliliters of sample volume. Typical filtration experiments in e.g. a nutsche filter require much larger volumes.
To characterize the filtration behavior, we have developed a 3D printed filtration cell which, in combination with an optical analytical centrifuge, enables a filtration experiment with a sample volume of approx. 300µL. Thus, the influence of protein engineering and crystal modification on filtration can be determined on a small scale. The flux density function, which describes sedimentation and filtration properties as a function of the solids volume fraction, is calculated from experimental data obtained with the filtration cell.

Lysozyme and alcohol dehydrogenase crystals serve as model protein crystals. Since lysozyme is polymorphic, i.e. depending on the crystallization conditions the crystals are either isometric, rod-like or needle shaped, the influence of crystal size and morphology on the filtration can be investigated well. Both protein crystals show...

CENTRISTAR - A novel software for filter centrifuges

I. Nicolaou*, NIKIFOS Ltd, Cyprus

The reliable selection, performance calculation and optimization of Filter Centrifuges is a big filtration challenge due to the complex phenomenology and requires praxis oriented, physical based and reliable mathematical models for all steps: formation, washing and deliquoring of the filter cake. Such mathematical models should contain only suspension and cake specific parameters, which should be determined by a theory based analysis of test data. The test data should consider in most of the cases not only laboratory experiments (by using a filter nutsche or a bucket centrifuge) but at least one pilot test should be carried out, in order to minimize the scale-up error.

By not considering a physically based and praxis oriented theory for the steps cake formation, cake washing and cake deliquoring, filtration tests are carried out unsystematically. Such approach is usually too time consuming and uneconomical. Besides that, such a purely empirical approach does not give the possibility to judge and correct the test results with the consequence, that the scale-up often leads to an unreliable performance calculation of industrial centrifuges. Furthermore, performance predictions for different settings and/or changes of the suspension properties cannot be reliably predicted.

In this paper a novel theory, which is used for the planning of the filtration tests and the analysis of the experimental results as well as for the calculation of the performance of Industrial Centrifuges will be presented...


F9 - Filter Media - Modelling, Artificial Intelligence, Machine Learning

Day: 24 October 2019
Time: 09:00 - 10:15 h
Room 2

Session Chair:
Dr. Ralf Kirsch

Filtration modeling and simulation with GeoDict, from filter media to filter element

M. Azimian*, S. Linden, L. Cheng, A. Wiegmann, Math2Market GmbH, Germany

Several key parameters are essential as input data to precisely simulate the filtration characteristics of a filter element at macro scale, e.g. simulating the particle filtration through a pleated filter, as shown in the center in Fig. 1. Boundary conditions and flow conditions, as well as input parameters related to the micro-structure of the media, should be defined. The main input parameters for the macro-scale simulation, which are related to the micro-structure of the media, are: permeability of the media, maximum particle packing density and maximum flow resistivity for both the depth filtration regime and cake filtration regime (four parameters), and fractional filtration efficiencies. These parameters are routinely obtained by flat sheet experiments through the filter media. However, the GeoDict software, a pioneer modeling and simulation tool can be applied to obtain these input parameters, thus reducing the need for these time-consuming and costly experimental tests.

The study of the micro-structure of the filter media is the starting point to understand, analyze, and optimize a filter...

Identification of fiber characteristics of a filter media based on artificial intelligence (AI) with GeoDict

A. Grießer, R. Westerteiger, A. Wiegmann*, M. Azimian, Math2Market GmbH, Germany

The study of the micro-structure of the filter media is the starting point to understand, analyze and optimize a filter. The first simulation step on the media scale consists of processing of µCT-scan images of a real media to prepare a detailed 3D micro-structure model of the filter media.

µCT-scans are a powerful tool to gain deep insights and ideas for innovation and for quality control in material engineering. GeoDict provides the tools for a better understanding of CT-images and paves the way to overcome the challenges of modern material engineering. Nonwovens are used in many industries, including fibrous media for filtration, glass or carbon-fiber reinforced plastics used in mechanical applications, or gas-diffusion layers used in fuel cells.

The performance of nonwovens is governed mainly by the spatial distribution, orientation, length, curvature and center line of the individual fibers. For fibrous media with binder, the volume/weight percentage and the spatial distribution of the binder material are also essential. With GeoDict, binder can be segmented from fibers in CT-scans even if they have the same gray values.

Using nonwoven micro-structures modelled with GeoDict, a neural network is trained to label binder with artificial 3-D scans, for which the distribution of the binder is known. After the training, the neural network also recognizes the binder in 3-D scans of real nonwovens, which were scanned with µCT or FIB-SEM. The results are...

Optimizing spunbond nonwovens for filter media production using a novel approach of machine learning and fiber/fluid simulations

S. Gramsch*, A. Sarishvili, A. Schmeißer, Fraunhofer Institute for Industrial Mathematics ITWM, Germany

Nonwoven filter media are getting more and more important due to their versatile properties. Nonwovens are classified by their production process. Mainly, there are three different nonwoven production processes: dry-lay processes, wet-lay processes, and extrusion processes. In this paper, we focus on the simulation of spunbond processes that belong to the class of extrusion processes.

The Fraunhofer Institute for Industrial Mathematics ITWM has developed a simulation tool called FIDYST that simulates the fiber dynamics in the air and the laydown process of the fibers on a transport belt of spunbond production processes. Hereby, the final web quality depends mainly on the air stream, but also on the material properties of the fibers. Simulating an existing spunbond process is state of the art. Optimizing or designing a new spunbond production process with specific properties of the resulting filter media requires a huge amount of simulation runs. Hereby, performing the corresponding CFD simulations is a very time-consuming task. Additionally, the fiber dynamics simulations include stochastic forces due to the turbulent air stream. Hence, a statistically significant number of representative fibers must be simulated in order to get realistic results.

In this paper, we present a novel hybrid informed learning approach that generates an optimal design of experiments for the simulation runs based on machine learning techniques. Furthermore, the general simulation method for spunbond processes and its application to filter media production is demonstrated...


G12 - Measurement Techniques I

Day: 24 October 2019
Time: 09:00 - 10:15 h
Room 4A

Session Chair:
Prof. Achim Dittler

Investigation of low-cost PM-sensors regarding the suitability for emission measurement for pulse-jet cleaned filters

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

In the field of immission measurement, cheap and compact low-cost PM-sensors have been established for monitoring particle concentration with high temporal and spatial resolution. The accuracy of these sensors is subject to many environmental influences, such as varying aerosol properties, particle concentration or relative humidity.

Another possible application for low-cost PM-sensors could be the emission measurement for industrial dust separation, like pulse-jet cleaned filter bags. Several filter bags could be equipped with low-cost sensors to investigate the contribution of individual filter bags to the total emission. The suitability of the sensors is still subject of research. The behavior during the filtration process in a VDI test rig for filter media has been investigated for the two low cost sensors OPC-N2 from the supplier Alphasense and PMS7003 from the supplier Plantower. A Welas 2100 sensor from the supplier Palas serves as a reference for the experiements.

The sensors are able to...

Measuring PM2.5 for cleanable filter media in ISO 11057 or ASTM D6830 tests using an optical aerosol spectrometer Promo® LED

P. Gäng*, FilTEq - Filtration Testing Equipment and Services GmbH; Germany

Cleanable filter media for pulse­jet cleaned filters are tested for operational performance and for particulate emission, where the focus shifts more and more towards particles smaller 2.5 µm. The measured data include generally the total dust concentration in the clean gas as an average over a defined number of filtration cycles and also, as an option, the determination of PM2.5 emission.

For high performance filter media which show very little particle emission, the gravimetric determination of the PM2.5 values becomes very time consuming and results in measurements of six or more hours, when using an impactor or cyclone.

Optical Aerosol Spectrometers are increasingly used in environmental PM2.5 measurements and are also certified by authorities. These instruments offer a viable and very fast method to also determine total dust concentration and PM2.5­values in the laboratory using a specified test dust under defined conditions. A further advantage besides the time saving potential is the very good time resolution and fast measurements of particle size distributions at every stage of the testing.

In this presentation a fast and easy method is introduced to determine PM2.5 emission optically instead of gravimetrically, using an Aerosol Spectrometer Promo LED with a measuring range from 150 nm to 10 µm. Test results gained on an ISO11057 reference filter test rig show...

A setup for measuring passenger car brake dust particles emissions

M.J. Lehmann*, S.E. Pfannkuch, E. Thébault, A. Beck, MANN+HUMMEL GmbH, Germany

Every mechanical braking action creates particles through friction on the brake disc and brake pads. These particles contribute to the PM10 emissions of vehicles. Some get collected on the rims seen as grey dust, others are emitted to the ambient air. Thus there is a need for a brake dust particle filter. But first, measuring size and concentration of such brake dust is a quite challenging task. The particle generation happens in the short event of braking and depends on brake load and preconditioning of the brake (disc and pads), e.g. temperature, braking history, to name some. However, a defined way of testing brake dust particle emissions is the pre-requisite for later investigation of filtration performance.

For release of an automotive brake system specific standards are available regarding braking events. Furthermore a braking sequences can be based on standards like WLTP driving cycle. For particle measurement various techniques could be selected, e.g. DMA, impactor, particle counter. For reliable data, the integration of such equipment in the air flow through the brake testing chamber is crucial.

We are going to briefly review published activities regarding measuring brake dust particles. We will then focus on our own measurements and ongoing research. We will describe the challenges and discuss results. Thereby we will focus on the effect of specific braking events on particle emissions.


G13 - Filter Element Design

Day: 24 October 2019
Time: 09:00 - 10:15 h
Room 4B

Session Chair:
Dr. Matthias Waldenmaier

Associating filters by series for optimizing the retention capacity of nanoparticles

A. Charvet*, S. Pacault, D. Thomas, Lorraine University, France

At this time, because of their very high-efficiency, the fibrous filters are the most commonly dedusting systems used for individual and collective protection. High efficiency particulate air (HEPA) filters are used in many applications: containment in medical, pharmaceutical or nuclear facilities, cabin air treatment in automobiles and aircrafts, vacuum and so on. In addition to their high efficiency, these filters, usually non regenerable, may have an important lifetime (i.e. high dust retention capacity) to avoid too frequent replacements.

In the specific case of nanoparticle filtration, the morphology and the size of these particles induce, for the same area density of collected particles, a faster increase of the pressure drop during the filter clogging than for submicronic and micronic particles. This further reduces the lifetime of the fibrous filter and makes even more important the optimization of its retention capacity.

To further improve the filter performances, a possible solution is to fabricate fibres with diameter lower than 0.5 µm. As the collection efficiency is a decreasing function of the collector size, nanofiber filters could generally achieve a high collection efficiency. Overall, the solution consisting of adding a thin layer of nanofibers allows increasing the collection efficiency but not countering the pressure drop increase during particle loading and consequently the energy consumption. A possible solution to reduce the pressure drop increase is a better distribution of particles collected within the fibrous filter.

In this study, our approach consists in a series association of microfiber filters with various properties...

A sustainable, modular and lean solution for pocket filter assembly

J. Kowalczuk*, D. Ciocco, A. Schwartz, B. Laurent, et al., Bollhoff Attexor SA, Switzerland

The construction and building sector requires a constant increasing need for pocket filters to respect and achieve satisfying air conditioning requirements. These pocket filters are consumables produced in various sizes and quantities according to the market needs. In spite of a standardized emerging size representing the big volume, there is a lot of room for non standard sized pocket filter production.

The aim of this paper is to present a modular, sustainable and efficient pocket filter production solution based on riveting, stitching, clinching and stitch-folding as joining techniques. This solution is coupled to a decision making tool allowing the implementation of best practices in lean management...

Pre-filter design of high efficient multilayer filter medium for pulse cleanable filter elements for challenging atmospheric conditions

F. Heuzeroth*, Hengst SE, Germany

The filter medium is the most important part of any filter element. It is possible to distinguish filter media into two major classes.

Surface filter media separate the dispersed phase mainly on the first layer of its embodiment. Particles which are bigger than the pore size of the first media layer start to build a filter cake on top of the material. The interaction between the filter medium and the separated particles are very week.

Depth filter media are the second material class. These separate the particles, depending on their size either on top of the media or in the depth of the material. This enable depth filter media to store a high volume of particles or humidity with a comparable low influence on its pressure drop.

Surface filter media are very suitable for pulse cleaning applications due to the point of particle deposition. But they react very sensitive on challenging atmospheric conditions like sticky dust or high humidity in combination with fine dust or salt. These conditions can lead to irreversible blockage of the surface filter media which requires a complete change of the used filter stage in the final application. Especially in air intake systems for gas turbines or turbo compressors this will lead to a loss of production capacity and thus very high cost for the plant owner.

Based on this knowledge it was the aim to design a filter media which merges the advantages of a depth filter with the high efficiency and cleanability of a surface filter media. To achieve this contrary aims the design of the filter media is crucial...


L12 - Cake Filtration - Enhancement of Continuous Vacuum Filters

Day: 24 October 2019
Time: 09:00 - 10:15 h
Room 1A

Session Chair:
Prof. Gernot Krammer

CORES - Vacuum drum filter for highly corrosive media

W. Knobloch*, ANDRITZ KMPT GmbH, Germany

Vacuum drum filters are state of the art in highly corrosive applications like producing Titaniumdioxyd (TiO2) in sulfuric acid (H2SO4) processes or in processes where slurries with a high content of hydrochlorid acid ( HCl ) is used. Conventionally these filters are made out of carbon steel covered with rubber lining to protect the structural design of the machine against corrosive attack. Disadvantage of this rubber lining is a partly embrittlement with tendency for cracks in relatively short time and therefore high maintenance costs with unscheduled production interruption.

In the past Filters complete made out form GRP were not long-term useable because of structural weaknesses of this material by chemical attacks along the glass-fibers due to capillary effects. Also Filter complete made out from Thermoplastics failed because of poor material properties. The new CORES-Vacuum drum filters are designed in a different way. Structural design is, dependent on size, made out of steel or completely out of GRP. In addition all parts in contact with the product are covered with a layer out of corrosion resistant, not reinforced plastic, which is commonly used in such industries, like PP (Polypropylene) or PVC. Furthermore some internal wetted parts can be completely designed out of resistant plastic and will be welded together with external surfaces out of plastic to have a closed surface for these corrosive applications.

The process functions of a vacuum drum filter remains still the same, but corrosion resistance of these new CORES-Filters are significantly increased compared with traditional carbon-steel rubber lined execution or conventional GRP-Filters without Thermoplastic-layer coverage.

Proof-of-concept of a newly developed device for the coupled generation and separation of crystalline particles

L. Löbnitz, T. Dobler*, H. Nirschl, Karlsruhe Institute of Technology (KIT), Germany

Increasingly shorter product life cycles and the need for small customized product quantities require plant and process innovations. Plants with high flexibility and low production capacities meet this need and are therefore in the focus of current research. The devices and plants with low production quantities should, if possible, also meet the requirements of large-scale production. This allows piloting in small-scale plants and stable scale-up if higher production quantities are required. Continuous processes and safety issues play a major role here. Aspects of small-scale, safe and flexible equipment with continuous operation are therefore fundamental requirements in apparatus development.

The aim of this research is the development of a novel apparatus concept, which combines different functional steps of an entire production process...

Prediction of cake solids content in vacuum belt filters from temperature data

T. Kinnarinen*, H. Montonen, M. Huttunen, J. Ahola, T. Lindh, V. Karvonen, A. Häkkinen, Lappeenranta University of Technology (LUT), Finland

The scope of this paper covers continuous dewatering of mineral slurries in a pilot-scale vacuum belt filter, where the solids content of cake is predicted based on temperature measurements. In the experimental study, apatite slurries with different solid contents were filtered at a pressure range of 0.2-0.7 bar. The slurry feed rate and the rotational speed of the belt were varied in order to vary the cake thickness and dewatering time. In addition to temperature measurements with conventional temperature sensors and a manually operated infrared thermometer, thermal imaging of filter cakes was demonstrated by using a thermographic camera. The data collected from the process was then used to predict the solids content of apatite at the point of cake discharge. The measured values of cake solids content varied between 87 and 94 w-%. It was found that...


L13 - Depth Filtration and Adsorption - Granular Beds

Day: 24 October 2019
Time: 09:00 - 10:15 h
Room 1B

Session Chair:
Dr. Kyung-Ju Choi

Feedbacks on performance tests with Filtralite® media compared to conventional media filters at pilot scale

C. Helmer*, O. Danel, J.-F. Robin, A. Brehant, SUEZ Environment CIRSEE, France

More stringent standards for drinking water quality and a global trend towards resource degradation have driven research toward improving the performance of treatment plants. Filtration remains a key step for drinking water treatment, being effective for the elimination of turbidity, colour and microorganisms. SUEZ is focused on continuous optimization of filtration performances aimed at improving the filtered water quality and/or reducing operating costs (energy, chemicals, water savings…). To this end, various approaches have been considered including the optimization of pretreatments and the replacement of traditional granular media with new ones such as Filtralite® products. Filtralite® is composed of expanded clay aggregates whose particle size (0,5-8 mm) and particle density (1050-1800 kg/m3) can be specifically selected. It offers innovative solutions to water facilities both for drinking water and wastewater as a goal of physical filtration or biological treatment. The use of this filter media concerns both the building of new plants and the refurbishment of existing plants. Today, Filtralite® is implemented worldwide with references for biological treatment especially for denitrification. The performances of this media for particle retention has been less investigated. In this context, a study was conducted to answer the following key questions:

  • What are the performances of Filtralite for particle retention in comparison with filter media commonly used on drinking water treatment plants in terms of filtered water quality and productivity?
  • What is the impact of raw water quality on the performance of Filtralite media?
  • What is the impact of filtration flow rate on the performance of Filtralite media?

New approaches for phosphate recovery applying iron hydroxide containing material in adapted sorption processes

A. Gerbeth*, B. Gemende, T. Riedel, F. Hascher, N. Pausch, University of Applied Sciences Zwickau; M. Leiker, R. Heiduschke, E. Schimann, P.U.S. Produktions- und Umweltservice GmbH, Germany

The recovery of phosphorous compounds from municipal waste water has gained special attention in the last decade because of the serious environmental concerns regarding the direct application of sewage sludge as fertilizer in agriculture. The main problems are the heavy metal contamination and the unknown effects of pathogens and drugs as well as other residues (e.g. microplastics and nanoparticles) potentially accumulating in the field crops and thereby introduced into human food chains. On the other hand phosphorus is an essential nutrient for plants and indispensable in modern crop cultivation. Phosphorus resources are limited and raw minerals from various sources are contaminated with heavy metal ions like cadmium and uranium.

Due to these reasons several research institutions, consortia of municipal companies and industrial associations are focussing the topic of phosphorus recovery, supported by current attempts in changing EU (and German) legislation. Beside the treatment of ashes from sewage sludge incineration several methods based on sorption and precipitation processes have been investigated. Implemented in industrial scale (and economically competitive) are mainly processes generating MAP (magnesium ammonium phosphate). However, there are only limited data available on the commercial application of these products in the fertilizer industry and agriculture.

It is well known that iron hydroxide containing materials are capable of binding oxo-anions from aqueous solutions even at very low residual concentrations. Former investigations of the project partners proved that iron hydroxide containing residues from mining water treatment had similar binding capacities e.g. for phosphate like commercially available products, but significantly lower resource consumption and production costs. Adaption of agglomeration process led to microstructured materials with optimized sorption kinetics and capacities. However, the desorption process was still the limiting step. Since the quality of the phosphorus containing product is substantial for the commercial application the current work is focussing on the development of an integrated recycling process with optimized combination of sorption/induced precipitation of mainly calcium phosphate compounds and their separation from the waste water stream...

Performance of adsorption system for water desalination using metal organic framework

N. Genidi*, A.S. Hassan, Hamad Bin Khalifa University, Qatar

The increasing demands of water for food production, human needs and due to the water shortage in many regions leads to a significant attention worldwide for approaching innovative technologies for water desalination. Therefore, adsorption Desalination became one of the attractive methods for water desalination, as it is environmentally friendly, operates at low-grade heat resources and requires low energy consumption.... The present work evaluates the water uptake of aluminum fumarate that ...


F10 - Numerical Analysis of Filter Media Pore Size and Structure

Day: 24 October 2019
Time: 10:45 - 12:00 h
Room 2

Session Chair:
Dr. Ralf Kirsch

Simulation-enhanced bubble-point testing capabilities on wire meshes

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

The Bubble-Point Test according to BS 3321 is a standard testing procedure to examine the quality of woven filtration media by identifying the size of the largest pore. The implementation of this testing procedure is fast and easy compared to other quality tests.

Unfortunately the determination of maximum pore sizes with the Bubble-Point Test in its basic form is only valid for perfectly cylindrically shaped pores. To apply the procedure on woven wire meshes, showing a variety of pore geometries, the so called capillary correction factor is needed. This factor usually has to be determined empirically by conducting a vast number of laboratory measurements.

GKD uses numerical tools to replace the time consuming capillary correction factor determination process by a simulation model. This multiphase simulation model makes it possible to immediately find a sturdy value for the capillary correction factor with only one computation necessary, regardless of the filter pore geometry. Recently new discoveries have been made which make the method faster and eliminate possible sources of error.

Influence of fiber size distribution on the permeability of fibrous filters

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

Predicting the pressure drop in fibrous filters and as a consequence the permeability is of crucial importance to many applications in air treatment. Many studies have been led on this topic, but they almost always deal with single sized fibers. However fibrous filters consist of blend of coarse fibers ensuring the mechanical rigidity and fine ones responsible for the high filtration efficiency. Simulations of flows for perfectly characterized geometries seem to be the most efficient tool to investigate this problem.

The aim of the work is to use simulation as a tool to a thorough study of the parameters influencing the permeability values in case of air filtration operations. The numerical study is performed with the GeoDict® code (Math2Market, GmbH). The mean fiber diameter ranges from 1 to 5 micrometers, the variation coefficient (ratio standard deviation over mean diameter) from 20 to 40 % and the packing density from 1 % to 25 %. Calculations were carried out for different media configurations fixing each of these variable. The approach is based on...

A multi-scale study of the permeability of compressed nonwoven filter media

M. Kabel, R. Kirsch, S. Rief*, S. Staub, Fraunhofer Institute for Industrial Mathematics (ITWM), Germany

The deformation of filter media and its impact on their flow and filtration properties has become an aspect of increasing importance when predicting filter efficiency and lifetime. While the deformation of the media due to the flow during operation was the subject of many experimental and simulation studies, only a few works addressed the effects caused by deformations of nonwoven filter materials due to manufacturing.

In particular, the change of material properties due to compression was the object of research. Media compression occurs during calendering), combination of media with supporting or spacer meshes (see [3]) and pleating (see [4]). In each of these scenarios, it turned out that taking into account the changes in the material volume fraction of the nonwoven is essential for an appropriate computer-aided prediction of flow and filtration.

The present contribution is devoted to the investigation of the permeability of compressed nonwoven filter media, similar to a previous work that was motivated by a better understanding of flow-induced material compression (see [2]). A filter material used in oil filtration was chosen for the investigation...


G15 - Filter Medium Design

Day: 24 October 2019
Time: 10:45 - 12:00 h
Room 4B

Session Chair:
Dr. Matthias Waldenmaier

Innovative design, analysis and optimization of woven filter media through experimental and computational methods

M. Azimian*, J. Becker, A. Wiegmann, Math2Market GmbH; A. Mantler, F. Meyer, F. Edelmeier, Haver & Boecker OHG, Germany

Besides the know-how and experience existing in HAVER & BOECKER OHG, the GeoDict software from Math2Market GmbH is intensively used to determine which wire cloth configuration suits the best for the specific field of application. By simulating different cases, it is possible to optimize existing wire cloth specifications and develop new ones.

Geometrical characteristics such as type of weave, wire diameter and mesh counts have an enormous impact on the specific flow and filtration properties of a wire cloth. Using specific cloth parameters resulting from the type of weave, aperture width, pitch and wire diameter, HAVER & BOECKER can depict the structure of single-layer and multiple-layer cloths as a real 3D model (Fig. 1) using GeoDict. Geometric parameters such as the pore size distribution and bubble point are then determined with the PoroDict module of GeoDict. The behaviour of the respective cloth or cloth laminate in various fluids such as air, water and fuel as a function of flow rate or differential pressure is predicted by the FlowDict module.

The simulation of the calibration process is demonstrated here by digitally compressing the media. The wire diameter, pore sizes and the permeability of the structure are changed by calibration. The simulations predict the difference of these properties before and after the calibration process.

Moreover, filtration experiments are carried out at the IUTA in Duisburg using the single-pass filtration test rig MFP 1000 from Palas GmbH. The tests use ISO A2 fine test dust particles. For finding the pressure drop of the clean media, the samples are measured only under air flow, i.e. without injection of dust particles. Afterwards, the particles are injected with the air flow. For defining the standard deviation, the particle size distribution in the air was measured four times in the upstream flow and three times in the downstream flow of the filter media. In other words, three samples for each kind of filter media were used in the experiments to ensure the confidence in the accuracy of the results. The filtration tests are conducted for roughly 75 seconds. The accuracy of this filtration time may vary due to the time the user needs to adjust the sample and later to take the sample out of the apparatus.

The filtration of solid particles from the fluid is also simulated. Filter life-time simulations were carried out using single-pass filtration parameters, i.e. with a constant contaminant concentration. The simulated quantities are the pressure drop, filter efficiency and count/mass of the deposited solid particles as a function of time. Furthermore, the deposited volume of particles and the pressure drop are animated as a function of time. In these simulations, the solid particles are spherical. Simulations are done by HAVER & BOECKER and in consultation with Math2Market. One of the challenges is to find out a precise distribution for the restitution coefficient of different particle sizes when impacting the surface. As restitution coefficient is a function of material properties, impact velocity and angle, particle size and shape, it can have a considerable effect on the filtration results when considering it in the collision models.

The results, namely the filter efficiency and pressure drop, obtained from the simulations are compared and validated with the experimental data. Using the proposed modeling and simulation technique, it is possible to predict the flow and filtration behavior of woven media and to optimize the micro-structure which suits the best for the specific applications...

Novel sintered metal filter elements: Performance evaluation in biomass gasification conditions

S. Tuomi*, E. Kurkela, M. Nieminen, M. Kurkela, I. Hiltunen, VTT Technical Research Centre of Finland Ltd, Finland; H. Balzer, A. Wierhake, GKN Sinter Metals Filters GmbH, Germany

Filtration is an essential step in biomass gasification processes. In synthesis gas applications, where full removal of gas contaminants is required, the filter unit is typically placed upstream the catalytic reformer in the purpose of shielding the reformer from dust deposits and preventing plugging of the catalytic layer. In state-of-the-art biomass gasification concepts, the raw product gas is cooled down to ca. 500 °C prior to filtration. This results in increased oxygen consumption in the reformer as the gas must be reheated after filtration to reach the targeted reforming temperatures of 850-950 °C. To improve the biomass-to-fuel conversion efficiency of biomass gasification-synthesis plants, the latest R&D efforts in this field have been targeted at operating the filter unit at gasifier outlet temperature (750-850 °C), which would eliminate the intermediate cooling and reheating steps. According to VTT’s estimate, the overall efficiency from biomass to Fischer-Tropsch liquids could increase from 53% to 58 %, if the filter temperature was raised from the conventional 550 °C level to 850 °C.

Filter elements that are currently available for hot gas filtration at temperatures up to 1000 °C are manufactured from metal alloys, high temperature insulation wool or fine ceramic granules. However, these state-of-the-art filter elements have certain restrictions, such as low ductility, high pressure drop or deficient corrosion resistance. With the aim to generate a metal-based filter material withstanding mechanical loads and corrosive conditions, GKN has developed innovative filter elements out of a modified Iron-Chromium-Aluminium powder (material No. 1.4767 mod.). The focus of this work was on evaluating the performance and corrosion resistance of these novel filters in biomass gasification conditions at temperatures up to 750 °C...

Use of metallic filters to prevent the degradation of HEPA filters in case of vapour release

S. Bourrous*, M. Barrault, A. Brunisso, INRS Institut National de Recherche et de Sécurité, France

Most of the industrial activities dealing with hazardous matter, such as nuclear industry use glass fibres HEPA filter to prevent the release of any airborne pollution in the environment. This technology, used for many decades is well known and its limitations in terms of particle holding capacity / mechanical resistance is either balanced by the use of pre-filtration systems such as inertial devices (cyclones, impactors …) or less efficient fibrous filters (Charvet et al. 2018). In the specific context of the nuclear energy production cycle, purification of the exhaust air needs to be ensured even in incidental context with vapour release. In this context, fibrous filters exposed to liquid aerosol present a quick an important pressure drop increase (Charvet et al. 2010) leading, in certain cases, to a break of the filters and the release of contaminants. If the purification process could be affected or inefficient, a static confinement of the contaminated areas should be applied. This needs to be done without any use of mechanic/electronic device in order to ensure the reliability of the system.

In this context, the important pressure drop increase of a metallic filter could be used to break the ventilation and to prevent contamination release. In this context, the maximal pressure drop depends on the efficiency/structure of the filter media. In this work, 4 different metallic filter medium, with different filtration efficiencies, and fibrous structure (fibre diameters, packing density layered structure) previously loaded with a solid aerosol simulating a contaminant (fluorescein soda) have been exposed to a water aerosol. The pressure drop


G14 - Measurement Techniques II

Day: 24 October 2019
Time: 10:45 - 12:00 h
Room 4A

Session Chair:
Prof. Gerd Mauschitz

Measurement of the PM2.5 oil concentration in water-oil miscible metal working fluid droplet emissions and a new aerosol generator for high oil-water-droplet concentrations

T. Laminger*, W. Höflinger, Vienna University of Technology, Austria, J. Weber, M. Schmidt, L. Moelter, Palas Gmbh, Germany; R. Piringer, AUVA, Austria

Especially the PM2.5 oil content of these oil-water emulsion droplet fraction (including the oil vapour), which are transported into the human respiratory tract, cannot be measured easily. A measurement device using a short-cut cyclone together with a flame ionisation detector (FID) can detect the oil quantity of the PM2.5 droplets. Together with the use of an optical particle counter also the oil/water ratio of these droplets can be determined, which is usually different compared to the initial working fluid concentration (Wlaschitz, 2007).

This measurement device can be also used for a standard test rig (ÖNORM Z1263), which can evaluate the PM2.5 oil separation efficiency of different filter media. For this purpose an oil-water droplet aerosol generator must be used, which should be rather compact and which can produce high droplet concentrations to ensure sufficient oil masses up- and downstream the tested the filter.

For a droplet disperser using a rotation tool, which imitates a moulding cutter, several parameters influence the droplet emission besides the rotation speed. Especially, the diameter of the rotation tool and the roughness (linked with the number of cutting edges on the rotating surface) are relevant for the generated droplet amount. Using a standard cutter rotating device, with small diameter produces insufficient droplet concentrations. Therefore a new compact aerosol generator (Cooling Fluid Generator - CFG 3000, Palas) was build using a steel brush with many steel needles with comparable small diameter, which can produce very high amounts of droplets.

In this work this new measurement method of the PM2.5 oil concentration with the use of this new generator is shown and the increased number particle numbers of the generator for different operation parameters are investigated.

Benefits of single photometer technology in an automated filter tester

G. Patel*, ATI - Air Techniques International, USA

This presentation will explore the pros and cons of using a single photometer architecture for filter test equipment, and the impact the selected architecture has on equipment performance, reliability and total cost of ownership.

The photometer is a critical component to the operation of an automated filter tester and is used to determine the amount of aerosol that is penetrating the media during testing. The ratio of the aerosol that is challenging the media combined with the amount that is measured penetrating the media is determined to be the filter efficiency in percentile measurement.

There are two schools of thought when it comes to the number of photometers and the placement of the photometer(s) within an automated filter tester. One architecture is to incorporate two photometers; one on the upstream media under test and one on the downstream. Both photometers could be either in-line with the aerosol source or they could be partially sampling the aerosol. An alternative architecture would place a single photometer downstream of the measurement, in-line with the aerosol source. Test results have demonstrated...

Performance of two online particulate matter measurement principles in a fertilizer industrial prilling tower

E. Krauss *, M. L. Aguiar, Federal University of Sao Carlos, Brazil

Inorganic fertilizer producers usually employ prilling towers to get nutrients bound together in even size particles. As consequence of prilling, fine particulate matter (PM) is emitted being its concentration typically sampled manually applying gravimetric methods. This work evaluates the operational performance of two distinct online PM analyzers, electrodynamic analyzer (EDA) and optical scatter analyzer (OSA) in an fertilizer industrial prilling tower against manual sampling. The results show an artificial high emission reading on the EDA every 15 min, what was found to be injection of cleaning steam in the tower, affecting the response, besides manufacturer states the analyzer can deal with changes on relative humidity. The contamination on the sensors affects the reading on both analyzers at some extent but only the OSA indicates the need for cleaning (span test less than 80%) while the self-check responses on EDA is always at 100%. This false response could be probably due to not optimal flow of purge air injected in the probe of EDA rod to keep it clean. It is also observed that...


L14 - Cake Filtration - Enhancement of Filter Presses

Day: 24 October 2019
Time: 10:45 - 12:00 h
Room 1A

Session Chair:
Dr. Pascal Ginisty

Benefits of filter presses with artificial intelligence (AI) support in the chemical and mining industries

A. Decker*, ANDRITZ Separation GmbH, Germany

In the chemical and mining industries, efficient filtration is a key process step in achieving high product quality. One of the most common products used for filtration is the filter press, which has gone through a lot of changes over the decades. One of the latest innovations in filter press development is the move towards Industry 4.0 and the Industrial Internet of Things (IIoT) as well as Artificial Intelligence (AI). The ANDRITZ technology group has combined findings gathered from IIoT with automation solutions for the filter press, creating new mechanisms and features that promise an increase in product quality and a decrease in operating costs as a result of process optimization.

Intelligent filter press features include solutions to increase efficiency, reduce downtime, and also enhance safety and monitoring functions. The key distinguishing functions of intelligent filter presses are monitoring of dry substance, intelligent washing cycles, monitoring of oil and filtrate quality, and intelligent pressure control.

Two of these solutions use a Smart Sensor inside the filter press that monitors the press and constantly compares the values reported with the nominal values so that the filter press can be stopped automatically if there are deviations from the norm. This provides an opportunity to increase efficiency, for example by suggesting an automatic washing cycle to keep the quality of the end product at a constant, high level. And it also improves safety by stopping the filter press in case of a pressure loss. This feature increases operating safety enormously. In addition, the oil levels and oil quality are measured constantly, ensuring continuing smooth operation and reducing OPEX costs by avoiding unnecessary oil changes.

Another central function of the intelligent filter press that increases efficiency is the monitoring of dry substance with Smart Sensors inside the filter press during the process. This enables the operator to stop filtration at the right time and reduce fluctuations in the cake moisture content. The intelligent filter press is often combined with intelligent filter elements, such as the LENSER intelligent filter plate and the Metris addIQ SmartFILTERCLOTH, to increase its usability. The SmartFILTERCLOTH is a filter cloth tagged with an RFID chip to help monitor use and suggest replacing a filter cloth at the right time, thus ensuring ideal filter cloth service.

The intelligent filter press and its features will be explained in this lecture, and two cases will be presented showcasing the use of an intelligent filter press and the benefits of its intelligent features in two plants, one in the chemical and one in the mining industry...

In-situ cleaning process of chamber filter presses with sensor-controlled and demand-oriented automation

P. Morsch*, H. Anlauf, H. Nirschl, Karlsruhe Institute of Technology (KIT); R. Werner, D.U. Geier, T. Becker, Technical University of Munich, Germany

The cleaning of plants for the chemical industry is essential to avoid cross-contamination, especially in batch operation, and therefore safe production. This is especially true for solid-liquid separation processes and especially for filtration. These apparatus have special requirements for cleaning because of the difficult to clean surfaces of filter cloths. The cleaning of filters is therefore often designed conservatively, which is equivalent to excess cleaning. A demand-oriented cleaning method based on image evaluation offers a lot of potential for optimization in this area in particular in order to reduce the necessary cleaning agent, document the cleaning result and reduce the amount of waste water produced. The latter point is particularly interesting considering the trend of rising wastewater costs in recent years.

Basis of this demand-oriented cleaning is the development of an optical residue detection, coupled with an automated nozzle system with a pulsatory and/or continuously operated nozzle lance for chamber filters. The cleaning process is then carried out using the following points....

New pilot for sludge electrofiltration and electrodewatering

J. Desabres*, B. Demasures, CHOQUENET SAS; E. Vorobiev, Technical University of Compiègne, France

Electrofiltration can be effective for “difficult to dewater” sludges. However, the electrodewatering is not yet commonly used in industry because of different side effects related to the electrical current application.

A new pilot filter-press has been developed by CHOQUENET in order to study the applicability of electro-technology on various industrial sludges.

The experiments with hydrocarbon sludge, fish farming sludge, and drilling sludge were realized. This study revealed several technical issues that have been solved for an industrial commercialization of sludge electrofiltration and electrodewatering.


L15 - Depth Filtration and Adsorption - Modelling and Simulation

Day: 24 October 2019
Time: 10:45 - 12:00 h
Room 1B

Session Chair:
Dr. Lars Spelter

Modeling the dynamics of filtration processes under variable flow conditions

R. Kirsch, S. Osterroth*, Fraunhofer Institute for Industrial Mathematics (ITWM), Germany

For many years, the multi-pass efficiency test according to the standard ISO 16889 has been a well-established and widely accepted procedure to evaluate lifetime and (fractional) efficiency of filter elements. However, the continuous ingression of test dust at relatively high concentrations and the constant flow rate have been subject to some criticism. A major argument for this is that under real operating conditions, both the concentration of contaminants and the flow rate will not be constant in time and therefore, a static multi-pass test with high ingression rates can underestimate relevant effects such as the resuspension of captured particles into the liquid.

Several alternative multi-pass test procedures were proposed to resolve this issue by prescribing conditions such as a variable flow rate for (at least part of) the test duration, a reduced base upstream gravimetric level and so-called stabilization phases during which no test dust is injected at all. Examples include initiatives by companies and industrial standards. A common feature of these test methods is a periodic alternation of the flow rate between two values with relatively short transition stages (see Fig. 1, left). Therefore, the evaluation of the filter performance includes the efficiency properties for two different flow rates and the filtration behavior during rapid changes of the flow.

Specialized computer simulation tools have proven to be very useful for the innovation and optimization of filter element designs. However, filtration models developed and validated for static flow cannot be expected to describe the dynamics in the filtration process under cyclic flow conditions. For instance, it was observed that filter media (or elements) with almost the same performance in a static test can display a quite different efficiency behavior when tested under variable flow conditions (see Fig. 1, right).

The present work is devoted to the extension of filtration models to the case of unsteady flow rates. In the case of media flat sheets and for the sake of quick identification of parameters, a one-dimensional model is sufficient to test the extended models. In particular, the influence of the cyclic flow (transition stages between the two flow rates) and the stabilization phases on the efficiency performance factors are investigated. The modeling approach is presented and illustrated by examples...

A flexible approach for meso-scale filtration modelling based on open-source CFD

U. Heck*, M. Becker, DHCAE Tools GmbH, Germany

Modelling of flow problems by computational fluid dynamics became more and more state of the art in many applications. Starting with automotive and aerospace applications in the early 80s, CFD prove itself meanwhile as an indispensable tool in nearly every sector with typical fluid flow challenges such as plant engineering, medical product development, environment analysis or HVAC.

The general advantage of CFD is that the base solution methods are general and can be applied to a wide range of flow problems. However, in certain applications additional closure assumptions based on experimental data need to be integrated into the code to cover specific effects. These effects very often happen at smaller time or geometry scales which cannot be resolved in all details and within the same model. Filtration applications represent a typical multi-scale problem: the geometric dimensions of the filters are in the range of millimetres to metres, while the relevant physical effects considering the particle and fibre interactions take place in the micrometre length scale.

Overall, the requirements of a filter modelling can be widely spread: In some situations, it might be sufficient to estimate an initial loading or initial deposition profile of particles in the filter media without considering the increasing resistance. In other cases, it might be important to consider the filter cake build up and local resistance increment during the filtration process.

The Open-Source CFD toolbox OpenFOAM has been designed to extend the common CFD models for specific needs. DHCAE Tools develops a flexible filter modelling system to cover a wide range of filter applications on a meso-scale. The target is to investigate flow behaviour ahead of the filter media in combination with local effects at the filter, e.g. increasing local resistance and cake generation effects...

Predicting collision efficiencies of colloidal nanoparticles in single spherical and fibrous collectors: A numerical study

D. Segets*, University Duisburg-Essen (UDE), Germany; H. Lee , D. Pui, University of Minnesota; S.-C. Chen, Virginia Commonwealth University, USA

Herein we present an investigation of the deposition of colloids onto granular and fibrous collectors by computational fluid dynamics (CFD) simulations [1]. In particular the collision efficiency under unfavorable conditions, i.e., like-charged surfaces, was in focus. Particle trajectories were analyzed in a Lagrangian reference frame using a discrete phase model (DPM).

By user-defined functions (UDFs) we incorporated interception as important deposition mechanism and calculated interaction energies between particle and collector surfaces utilizing the extended Derjaguin‐Landau‐Verwey‐Overbeek (xDLVO) theory. Adhesive and hydrodynamic torques acting on deposited particles were compared through the developed UDFs to consider particle detachment. Within each DPM process, all abovementioned calculations on every particle are performed continuously, allowing to understand particle deposition under different physico-chemical conditions. Simulated data on collision efficiencies for the granular collector were in good agreement with theory and experiments. Simulations for the fibrous collector showed that...


F11 - Numerical Methods for Filter Media Characterization and Improvement

Day: 24 October 2019
Time: 13:00 - 14:15 h
Room 4B

Session Chair:
Dr. Andreas Wiegmann

Simulation of fine fiber generation in electrospinning and meltblown for filtration

D. Hietel*, W. Arne, R. Wegener, M. Wieland, Fraunhofer Institute for Industrial Mathematics (ITWM), Germany

Spinning processes for fibers, filaments and nonwovens differ in their mechanism to draw the melt or solution to generate the resulting fiber diameter. On the one hand there are processes like spunbond or staple fibers where simply the spinning speed in relation to the hole throughput determines the diameter which is typically above 10 microns. On the other hand there are processes like electrospinning or meltblown where additional acceleration steps lead to much finer diameters down to submicron or nano fibers. Their productivity in fine fiber generation enables a wide spectrum of nonwoven-based filtration applications.

In this paper we discuss the modeling and simulation of electrospinning and meltblown concerning the filament dynamics in these processes....

Improving depth-filter media using a new multi-scale approach

M. Kuhn*, C. Geerling, H. Briesen, Technical University of Munich; M. Azimian, A. Wiegmann, Math2Market GmbH, Germany

Depth filters are employed for various purposes, for the purification of liquids as well as the cleaning of gases. The technique is also used in different industries, such as energy conversion, waste water treatment, beverage technology, and air conditioning. With current manufacturing methods, precisely-defined gradient media for depth filters can be built. However, it remains unclear which gradients of local filtration properties are desirable for different applications. Therefore, we aim to contribute to a general design method for depth filter media with the present study. A multi-scale approach is introduced in which pore-scale simulations are combined with corresponding continuum models. The present work is based on two previous studies [1,2] conducted by separate research groups which combine their findings here.

Methodologically, pore-scale simulations (software: GeoDict, supplier: Math2Market) of depth filtration are conducted from which the parameters of continuum models are determined. A representative domain size for all pore-scale simulations is determined in a preliminary study. On the continuum scale, predictions are made with respect to the local separation properties of the filters, as described by the filter coefficient (software: Matlab, supplier: Mathworks). Based on optimal control solutions, the local filter coefficient is determined so that deposition within the filter media is homogeneous along the filter depth because inhomogeneous clogging is a known problem of depth filters. In the optimization, the constraint of a given overall filtration efficiency is applied. Subsequently, the optimized filter-coefficient trajectories are translated back to the pore scale and the results are validated. The described strategy is conducted for a fibrous filter medium (I), composed of fibers of two different diameters, as well as for a packed-bed filter which consists of a binary mixtures of spherical particles (II). For both case studies, it is found that...

Computer-aided study of the diesel-water separation efficiency of screen meshes

O.O. Elsayed*, R. Kirsch, S. Osterroth, Fraunhofer Institute for Industrial Mathematics (ITWM); S. Antonyuk, Technische Universität Kaiserslautern, Germany

In the last decade, many changes and regulations were applied in order to reduce the emissions out of diesel engines, which led to major changes in the chemical composition of the diesel by reducing its sulfur content. In addition, biodiesel fuel is of increasing importance in the automotive and energy sectors. These changes on the fuel helped to reduce hazardous emissions, but at the same time, they affected the performance of water-diesel separators due to their lower surface tension with water. Since water intrusion is inevitable due to transportation, storage, or clearances, it is important to improve the protection of the engines from moisture and to ensure efficient combustion processes (see e.g. [1], [2]). This in turn requires a good understanding of the transport and deposition of water droplets inside the coalescers. In order to use computer-aided engineering technology for the optimization of the separation process, reliable models for the prediction of the separation performance of the media are needed.

The fact that filtration and separation are by nature phenomena that connect several size scales imposes a challenge for both modeling and simulation. On the scale of the diesel fuel filter element, quantities like geometry of the medium, its (local) flow resistance and the (local) concentration of the water are relevant. On the other hand, properties of the separator material (e.g. wettability, contact angle), and microscale properties such as mesh geometry and local distribution of water droplets are influencing the deposition of water in/on the medium. This in turn changes the distribution of flow resistance and therefore, the transport of droplets towards the medium. It seems obvious that in order to obtain a macroscopic model, a detailed study of the separation process on the microscopic scale is mandatory.

The present work uses the Computational Fluid Dynamics (CFD) package OpenFOAM®, more precisely a variant of the module “interFoam”, to simulate the interaction of water droplets in a diesel fuel flow with a screen mesh. For the treatment of the liquid mixture, the module utilizes the Volume of Fluid method (VoF)...


G16 - Particles for Filter Testing

Day: 24 October 2019
Time: 13:00 - 14:15 h
Room 4A

Session Chair:
Prof. Thomas Laminger

New synthetic nano-aerosol for accelerated realistic ageing of air filters

J. A. Marval Díaz, L. Medina, E. Norata, P. Tronville*, Politecnico di Torino, Italy

To assess reliably the energy impact of air filters it is essential to ascertain changes of their airflow resistance during their whole service life and not just when they are clean. This is true in the case of current filters on the market and for future filter designs too.

An air filter’s ageing behavior is strongly dependent on the characteristics of the challenging aerosol during its service life and on the characteristics of the particles collected on the fibers. The relevant aerosol characteristics include its particle size distribution, the shape of the particles, and whether the particles are solid or liquid. The size (diameter) of aerosol particles is especially important in determining the kinetics of the air filter loading and clogging process. In general, the airflow resistance increases more significantly as the size of the loading aerosol decreases.

Current laboratory standards simulate the ageing of air filters by dispersion and loading of synthetic dusts with particle size distribution completely different from a typical urban atmospheric one. This is considered acceptable for rating filters and comparing their performance against each other, but it will not result in accurate prediction of the airflow resistance increase, likely to occur in a real environment. Therefore, the energy-use assessment cannot be reliably estimated by means of current laboratory test dusts.

We can better predict the impact on air filter resistance of their service time if we perform an accelerated ageing procedure by using synthetic aerosols with a thoughtful size distribution like, for example, a reasonable simulation of typical urban atmospheric aerosols. Knowing how a pressure drop realistically changes in time will allow to estimate optimal air filter changes and to establish a meaningful energy labeling system. ISO 16890-1:2016 defines...

...We describe various methods for generating nanoparticles having approximately the same particle size distribution of a typical urban aerosol, but at higher mass concentrations. The purpose is to allow accelerated ageing in a similar way to what happens in actual service conditions. The paper describes the thermal aerosol generator chosen to produce the desired particle size distribution of the synthetic aerosol in an existing test rig according to ISO 16890:2016 specifications. This generator produces a high amount of nanoparticles by burning a salt stick (e.g. made with KCl) with an oxy-propane flame. The salt vapor condenses in the air stream to form a cloud of ultrafine particles...

Comparison of different discharging methods and test aerosols for measuring the efficiency of electret filters

S. Schumacher*, R. Jasti, C. Asbach, Institute for Energy and Environmental Technology e.V. (IUTA); M. Kerner, S. Antonyuk, Technische Universität Kaiserslautern, Germany

Electret filters find many applications since they offer a high initial filtration efficiency combined with a low pressure drop. They carry electric charges on the fibers, which interact either directly with charged particles by Coulomb attraction (electrophoresis), or by interaction with induced dipoles in both charged and uncharged particles (dielectrophoresis). A well-known disadvantage of electret filters is that the charge stored on the fibers can drastically degrade with time under exposure to particles, gases or humidity. In order to assess this effect, the testing of particle filters for general ventilation according to EN 779 required the immersion of the filter media in liquid isopropyl alcohol (IPA). In contrast, ISO 16890 which recently replaced EN 779 requires discharging of the filters in IPA vapor saturated air. So far, there is only little knowledge about the comparability of the two methods.

In order to gain new insights, various filter types were immersed in liquid IPA and discharged with IPA saturated air. Before and after discharging, the fractional filtration efficiencies were determined with a sodium chloride (NaCl) aerosol. For several of the filter types, it turned out that...

Testing the efficiency of process filtration of viruses in gases with protein nanoparticle surrogates

M. Nazir*, Memsep Filtration Ltd., UK; R. Dalal, A. Kamble, S. Singh, A. Sharma, R. Dalal, FSP Technologies, India

The efficiency of virus filtration in gases is an area where the generation of accurate and representative data is difficult to replicate. Process filters to remove viruses and bacteria from gas streams are generally in the range of 0.2µm; an order of magnitude larger than many viruses. The adsorption and Brownian motion mechanisms of filtration allow a high retention of small particles in gases, and thus most viruses can be retained by current process filters. The Parenteral Drug Association1recommends that sterile gas filtration is carried out with filters that have been validated to remove bacteria in liquids; such PTFE membrane filters are also known to effectively remove coliphage viruses of 25nm in size and even particles of 3nm. Depth filters incorporating glassfibre media are also able to retain viruses in gases, albeit with a risk of breakthrough if the filter becomes wet. In recent years, research has focussed on ascertaining the virus retention efficiency of HEPA filters manufactured with polymeric nanofibre media.

Current methods to assess virus retention using surrogates are based on the retention of oil droplets and sodium particles; neither resembles the surface characteristics of viruses, which are critical to the efficiency of separation.

The use of protein nanoparticles as a surrogate is a practical and reproducible tool that challenges filters with particles that closely replicate the properties of viruses. Braas et. al., 20002 have shown, how such particles show a similar behaviour to adenovirus in aqueous phase, liquid-liquid separations and ion-exchange chromatography; this is indicative of similar surface properties and thereby adsorption characteristics to filter media. The aim of the current project is to explore the application of suitable surrogates based on protein nanoparticles to test the retention of viruses, with the surface properties of the chosen challenge particles taken into account...


L16 - Dewaterability of Sludges

Day: 24 October 2019
Time: 13:00 - 14:15 h
Room 1A

Session Chair:
Dr. Pascal Ginisty

Sludge solids concentration: Which are the limits ?

P. Ginisty*, IFTS - Institute of Filtration & Techniques of Separation, France; J.B. Kopp, Sewage Sludge Treatment Consulting KBKopp, Germany; A.K. Melsa, L. Spinosa, International Organization for Standardization - ISO TC275/WG6 Working Group

Sludge is produced by wastewater treatment and is in the form of a suspension with a water content of 95-99%. After thickening, sludge has still a water content of 92-97% and needs dewatering. The main objective of dewatering is to produce sludge that can be more easily transported and safely handled, valorized or disposed of. One of the greatest problems of parameters and tests usually adopted for sludge characterization is that they are generally specific to the method of treatment but not able to give fundamental information on the sludge in question (Spinosa, 2013). In particular, for the evaluation of performance of several sludge management operations, an important role is played by basic parameters, such as particle and floc size distribution, rheological properties and water distribution. The latter parameter gives important information on the availability of different types of water to be removed according to the type and intensity of their bonding to the solids. Scientific papers (Vesilind 1997,; Kopp 2000,; Vaxelaire, 2004) try to classify the different types of water introducing some terms, such as free water, bulk water, interstitial water, flock water, internal water, capillary bound water, vicinal water, surface water, water of hydration, intracellular water, physical or chemical bound water…., but most people seem to use these mentioned terms interchangeably and debates are quite confusing as most of the types of water proposed are difficult to be precisely defined and to quantified.

In the framework of ISO/TC 275 (International Standardization Committee devoted to sludge management) work, definition of terms needs to be clarified and a simpler classification is proposed with 2 main categories...

....The paper proposes to illustrate different concepts by pointing out experimental results obtained with a given wastewater sewage sludge: drainage tests, floc shearing/compression tests, dryness limit and thermogravimetric methods and will show how much the modification of floc structure can change the state of water in sludge and the kinetics and amount of free water removable by thickening and dewatering processes. Comparison of these values to dryness obtained at pilot and full scale centrifuge decanter will be made...

Why dewaterabilty of sewage sludge occurs upstream - A model to quantify the effects

J. B. Kopp*, Sewage Sludge Treatment Consulting KBKopp, Germany

Mechanical dewatering of sludge is a key technology to reduce disposal costs. It can be observed that ignition loss of sewage sludge in the last ten years increase continuously and dewatering results decrease even if god degree of degradation are achieved in anaerobic digesters. This can be explained by change in organic compound in primary sludge (PS) itself and increasing amount of waste activated sludge (WAS).

To optimize sludge dewatering processes, the dewaterability of sewage sludge needs to be understood. There are two categories of water in a sewage sludge suspension: the free water content with no physical binding to sludge particles. By mechanical dewatering of sewage sludge only this free water content can be separated. The second category is the bound water, which is the sum of internal water, surface water and chemical bound water. The internal water is bound in the interstices inside flocs and particles physically by capillary forces in pores up to approx. 10 µm. Surface water is bound on the surfaces of particles by physical and chemical adhesive forces. At least chemical bound water is fixed in cells, gels, EPS and by hydration. The structure of flocs mainly determines the amount of bound water and dewatering results. Therefore dewaterability occurs upstream. A model was generated to explain the main influences on dewaterabilty in wastewater treatment plant. Further the effect of new technologies like vacuum degassing, thermal hydrolysis and phosphorus precipitation as struvite on the water binding will be quantified...

Filtered dry stack tailings: The ‘state of play’ for high capacity tailings filter plants

R. Whittering*, Ausenco, UK; M. Pyle, G. Lane, Ausenco, Australia

Tailings storage facilities are generally the most significant environmental liability for mine permitting, operation and long-term closure. Tailings filtration and “dry stacking” reduces the risk of liquefaction, improves rehabilitation and minimises water consumption compared to conventional wet impoundments and is therefore considered to be environmental best practice for tailings management.

This paper describes the ‘state of play’ for current filtration technologies, industry trends, and key considerations for engineering filtration and stacking systems at high throughputs. Cost modelling completed as part of several case studies illustrate how material characteristics and project-specific drivers influence the stacking system selection, stack design, target moisture, filtration strategy, technology selection, reliability/maintainability and circuit de-coupling to ensure design objectives are realised whilst maximising project value...


L17 - Backwashing Filtration

Day: 24 October 2019
Time: 13:00 - 14:15 h
Room 1B

Session Chair:
Prof. Gernot Krammer

Cost and energy saving through automatic backwash filter in PE production

S. Schöpf, W. Watzinger*, Lenzing Technik GmbH, Germany

Evaporation is one of the most cost intensive and complex forms of chemical recovery, but sometimes unavoidable. Therefore it is important to keep the flow of this process step as small as possible.

High Density Poly Ethylene (HD-PE) production with hexane as carrier fluid is one example therefore. Typically after the catalytic reaction the HD-PE is fed into a hydro cyclone, whereas through the underflow the majority of worthy product is separated from the liquid, but the overflow of the hydro cyclone still contains a non-negligible amount of product plus wax-like intermediate stages of the reactant and is typically evaporated.

After several unsuccessful trials with disposable filters as well as standard backwash filters, a big chemical company, which is producing HD-PE on two sites in Germany, installed the Lenzing OptiFil®. Although the particles are very small at 5µm and below, the Lenzing OptiFil® provides a reliable barrier for the particles leading to the fact that...

Influencing parameters to improve the regeneration efficiency of backwashing filters

P. Morsch*, H. Anlauf, H. Nirschl, Karlsruhe Institute of Technology (KIT), Germany

In industrial solid/liquid separation, the removal of fine particles (≤ 10 µm) in a suspension with a low solids content (0.01-1 v/v %) is a challenging and demanding task. Especially the cake filtration is emphasised as advantageous principle for separation of such kind of suspension. This separation occurs in a wide array of industrial production applications such as metal processing and treatment industries and has some advantages compared to other separation principles. In order to achieve the required purity, different types of filters, such as candle and leaf filters, can be used. The selected filter will be used (semi-)discontinuously and the actual “filtration” process step is just as important as the subsequent “regeneration” of the filter cloth. In case of an improperly regenerated filter, the next filtration process becomes shorter until a subsequent regeneration is required. This behaviour is presented in the well-known filtrate flow – time – plot in figure 1. In the case of a properly regenerated filter (a), the filtrate flow at the beginning of each step is still equal whereas the initial filtrate flow decreases in the case of an improperly regenerated filter (b).

With respect to the field of applications, the removal procedure has revealed that there is potential for improvement. A properly regenerated filter cloth highly depends on the interaction between the particle system and the filter cloth. In order to guarantee the removal of the filter cake, the applied removal force has to be larger than the adhesive forces. Furthermore, to remove the filter cake in large fragments, the removal force has to be lower than the cohesive force. This effect come out by variation of the filter cake thickness. In case of a low filter cake thickness and/or very porous filter cakes the remaining filter cake on surface is much higher compared to a higher filter cake and/or a particle system with a higher specific flow resistance. The difference between that cases is give n through the cohesion by a constant adhesion.

This presentation shows the influence of selected process conditions during backwash filtration...

Assessment of filter media properties for automatic self-cleaning filters

T. Buchwald*; U. Peuker, Technical University Bergakademie Freiberg, Germany

Surface and sieve filtration are the dominant separation mechanisms in clarifying filtration, where large amounts of liquids need to be cleaned from small amounts of particular contaminants, while achieving high volumetric throughputs. In common cake filtration, these blocking mechanisms are only happening during the initial stages of filtration and are rarely relevant to the process. This is why the process of clarifying filtration has been studied very little in the past.

In automatic filters, filter candles are continuously cleaned by backwashing the filter medium with filtrate. The cleanability of the filter medium depends on the medium geometry as well as the separated particulate matter. There is no precise statement in literature whether the pressure pulse or the maximum pressure is the relevant parameter for cleaning efficiency. Furthermore, unlike in gas cleaning, there exist no standards for the evaluation of backwashable media in liquid filtration.

Within the framework of an industry-advised research project, a new experimental filtration apparatus was developed in which a planar filter medium can be backwashed repeatedly, after a specified criterion is reached. The new laboratory rig makes it possible to evaluate different filter media for their suitability as a filter medium in automatic backwash filters...


L18 - Froth Flotation and Liquid/Gas Separation

Day: 24 October 2019
Time: 13:00 - 14:15 h
Room 2

Session Chair:
Prof. Ioannis Nicolaou

Optimization of gas input in aqueous two-phase flotation (ATPF) for enzyme purification

L. Jakob*, J. Singer, H. Nirschl, Karlsruhe Institute of Technology (KIT), Germany

The purification of industrial enzymes from complex biosuspensions represents a major challenge for the bioprocess. Many separation steps are necessary to capture the target protein from the fermentation broth and to increase the purity up to the final product. During downstream processing, various processes are used, such as centrifugation, filtration, precipitation, extraction or chromatography, so that losses and energy costs of the individual steps sum up and the purification costs for enzymes usually represent more than 50% of the production costs.

In protein extraction from complex biosuspensions, aqueous two-phase systems (ATPS) ensure mild conditions and high selectivity against the target protein. ATPS are formed when a polymer or a lower alcohol is dissolved in water with another polymer or salt above the critical concentrations (mixing gap). During extraction, impurities (cells, cell debris, media components, ...) remain in the heavy lower phase while the target protein diffuses into the upper, lighter phase.

The flotation of enzymes in aqueous two-phase systems (aqueous two-phase flotation, ATPF) combines the selectivity of the extraction with the high mass transfer of the flotation. By introducing gas bubbles into the two-phase system, proteins with their hydrophobic part attach themselves to the gas-liquid interface and are transported to the upper phase after the bubbles have risen (see Fig.1). This allows to perfom "Capture" and "Clean" in one step. The ATPF was described for the first time2 in 2009 and promises to be an efficient alternative to conventional purification processes of biotechnological products by eliminating several separation steps warranting mild conditions.

However, more research is needed to develop the new technology on its way to an industrial use. Especially the gas input in the two-phase system has to meet several demands.

Within the research project, ATPF will be fundamentally investigated for its application potential for the purification of industrial enzymes...

Air separation from a hydraulic tank using special meshes

Z. Aouf, Abou Bekr Belkaid University, Algeria; J. Gorle*, Parker Hannifin, Finland

As a device to store the hydraulic oil, dissipate the excessive heat from the fluid, to condition the oil and supply it to the downstream components, the hydraulic tank is regarded as a multi-functional system in a hydraulic circuit. An appropriate design with the right installation of subsystems such as filters and indicators is critical to ensure a flawless operation of the hydraulic system. The air bubbles in the hydraulic flows, either through the leaks or due to the meta-stability of the fluid, not only produce the noise and vibrations, but also reduce the system’s efficiency and damage the components via stress corrosion. Deaeration of hydraulic tanks is therefore an absolute necessity.

In this work, the air bubbles in the return line flow is separated from the oil in a hydraulic tank using special meshes...


F12 - Advanced Filter Media for Gas Filtration

Day: 24 October 2019
Time: 14:45 - 16:00 h
Room 4B

Session Chair:
Prof. Arunangshu Mukhopadhyay

Pore Size of the spunlaced nonwovens and optimization of the parameters for air filtration application

A. Patnaik*, L. Maduna, Cape Peninsula University of Technology, South Africa

Nonwovens are widely used for various applications including air filtration. Generally needle-punched nonwovens are widely used for air filtration. One of the drawback of this process is the fibre breakages due to harsh needle action leading to poor service life of these filters. It is particularly important for filters used in coal fired power stations where durability of the filters played an important role. Other way of producing filters is by spunlacing process. In this process, the needles are replaced by the high speed water jets, therefore, damage caused to the fibres are minimal. This work explores the use of spunlacing process for manufacturing filters suitable for air filtration applications. The mean pore size of the nonwovens plays an important role in determining the filtration properties and pressure drop characteristics.

The aim of the study is to find out the optimized mean pore size suitable for filtration application in coal fired powered stations while using the spunlacing manufacturing technology...

smartMELAMINE® - The first melamine meltblown nonwoven

C. Löning*, smartMELAMINE d.o.o., Slovenia

smartMELAMINE® belongs to the class of high-performance materials, it does not burn, does not shrink and does not melt, remains stable even at higher temperatures and is UV-resistant. smartMELAMINE® is an excellent thermal and acoustic insulator and is also well suited for filtration due to the fine fibers and its chemical resistance.

smartMELAMINE® nonwoven is available also with very fine fibers, at around 1 - 2µm fiber diameter or even below, reaching filter classes up to F9.

Aramid type filters and other traditional filters in hot-gas filtration generally have much coarser fibers compared to smartMELAMINE®. With the addition of a smartMELAMINE® filter efficiency increased up to 10x.

smartMELAMINE® nonwoven can also be cut into short-cut fibers, which can then be quite easily dispersed in water and used in a wet laid process for the production of paper like filters. Due to its high temperature and chemical resistance it can be an adequate synthetic substitute to glass fibers.

There are different potential applications in the fields of thermal and acoustic insulation or filtration for the use in: automobiles, trains, buses, trucks and aircrafts; protective workwear; filtration; construction and various industrial applications.

Welstrat: An innovative filter media for hot gas filtration application

L. Joshi*, N. Shukla*, Welspun India Ltd., India

  • Welspun’s filter media made up of special blended synthetic fibers, singed and calendared delivers superior performance due to excellent acid, alkali and hydrolysis resistance over 100% polyester felt.
  • Welspun’s media is suitable for mid temperature range applications like F&B boilers and Ferrous alloys with thermal shrinkage less than 1% at 180 degrees for 1 Hr.
  • Its High permeability and lower mean pore size due to hybrid technology results in better efficiency and less energy consumption.
  • This paper also covers the comparative study of physical, chemical and performance properties of Welstrat and 100% PET and 100% M-Aramid material.


G17 - Monitoring and Control

Day: 24 October 2019
Time: 14:45 - 16:00 h
Room 4A

Session Chair:
Prof. Markus Lehner

A new methodology for continuous scanning of particle aerodynamic diameter and application to filtration performance assessment of a room air purifier

S. Payne*, J. Symonds, Cambustion Ltd; T. Johnson, Cambridge University, UK

The Aerodynamic Aerosol Classifier (AAC) is a novel instrument that classifies particles based on their aerodynamic diameter. This is accomplished by passing the aerosol between spinning concentric cylinders with a coaxial sheath flow. Particles that have aerodynamic diameters larger than the AAC setpoint are dominated by the centrifugal force and impact the outer cylinder surface, while smaller particles remain entrained in the sheath flow; only particles with a narrow range of aerodynamic diameters pass through the AAC classifier. Particle sizes between 25 nm and 6.7 microns can be selected independent of the aerosol charge state, with a high transmission efficiency limited only by diffusion and impaction losses.

This technique can be used to measure an aerosol’s aerodynamic size distribution by stepping the AAC setpoint while recording the classified particle number concentration (Johnson et al., 2018). However, similar to the Differential Mobility Particle Sizer (DMPS) this stepping procedure requires long measurement times to achieve reasonable spectral resolutions. To overcome this limitation, Johnson et al. (In Preparation) recently developed the scanning AAC inversion. Following a similar methodology as the Scanning Mobility Particle Sizer (SMPS) inversion (Wang & Flagan, 1990), this new approach allows the aerodynamic size distribution to be continuously measured by varying the classifier speed while measuring the classified particle concentration. By continuously varying the classifier speed following an exponential function, the change in the centrifugal force a particle experiences during its classifier residence time is independent of its inlet time. Furthermore, when the scan time is sufficiently longer than the scan speed ramping constant, the scanning AAC transfer function converges to the same shape as the steady state transfer function.

This study uses a scanning AAC to collect accelerated measurements of the ambient air particle size distributions in a room before and after the operation of a commercial room air purifier. A filter sample was taken from the air purifier and measurements of the size-dependent filtration efficiency were made, using the AAC to select monodisperse test particles by aerodynamic diameter. The aim was to assess the air purifier performance by comparing size-dependent penetration measurements with the full real-world ambient spectra...

VisionAir Clean for clean room air change rate optimization

J.W. Rajala*, S. O’Reilly, AAF Flanders, USA

A challenge and decision in the clean room design process is how to determine the required supply air volume to achieve the target cleanliness classification in a given application. Historically, these decisions are made based on experience and following practices and guidelines that have evolved from multiple sources which we can today say have been conservative at best.

Following these practices will supply enough clean air to meet the classification requirements, however at the expense of overdesigning the system with higher capital costs and by default, higher operating costs than necessary. Also, if the experience based approach leads to underestimating the supply air rate, the result could be contamination levels that are too high and costly work to fix the problem. AAF Flanders has developed a scientific approach to this problem for predicting the contamination in a clean room based on sources of particle generation, air filter efficiency and air change rate.

VisionAir Clean is a web based application that allows the user to see factors that impact indoor air quality and energy consumption related to the air filtration system. Starting from the PM 2.5 levels in the outdoor environment, this program displays the particle count in a room as a function of the air change rate and compares it to the selected cleanliness standard requirements. VisionAir Clean also accounts for particle generation within the clean spaces, such as people in various garment types and process related contamination, and shows the changes in contamination as inputs are modified. Filter test data are loaded into the program to estimate filter life and optimize the change-out cycle based on balancing the costs associated with the filter (purchase price, labor, disposal, etc…) and the energy consumption as the filter resistance increases with dust load. The energy cost impact due to resistance across housing components, such as dampers and diffusers, are also taken into account.

The output of this analysis is an optimized solution for air filtration applications, specifications, drawings and models of products, reports indicating total cost of ownership and air quality, a 3D visualization of the products and a technical library of relevant industry information...

Smart air filtration, air filters go digital - Chances and risks of new roads to market

T. Stoffel*, DELBAG GmbH, Germany

Many areas of our daily lives lead us to encounter the term “smart”. Smart phones, smart watches, smart illumination systems, smart vehicle and smart facility management cross our paths almost everywhere.
Once you understand the term smart as a digital and demand specific control system, it appears only a question of time until this terminology reaches the world of air filtration. Already today highly efficient air treatment systems are closely controlled and adjusted according to the actual ventilation requirements in the building. Measuring CO2 concentrations, for instance, makes it possible to adjust the amount of fresh air in the system, as much as dynamically controlling necessary heating and cooling loads. Contemporary air treatment systems are continuously checking and adjusting their operational configuration.
The mere measurement of CO2 concentrations does not automatically make any system smart, by any means. Just as important as determining the CO2 concentrations are the fine dust contaminations, VOCs, nitrogen oxides, ozone, carbon monoxide, relative humidity, etc. in occupied space. Each of these factors may also influence one another, which has to be respected. A comprehensive and continuous data analysis already makes it possible now to accustom the filtration performance to the current requirement of the air treatment system. Filter units can individually be activated for ventilating a building or they are selectively taken out of the main air stream.
This still does not make a filter smart. The intelligent feature in this set up is the air treatment system, that guides use, or non-use of the filter unit. Filtration only becomes truly smart, once the filter actively provides information about its current status into the air treatment control system. The future will introduce microchips in filter elements that provide precise information about the current pressure loss, humidity, and possible microbiological growth.
Sensors in the filter frames will make date of filter commissioning as well as the exact position of filter available to the operator of the facility. Hereby the filter can actively suggest and optimal change interval to the local facility management and can also forecast expected increase in pressure loss, the expected additional operational costs, the replenishing costs and calculate a break-even point. The data needed for replenishing are naturally web-based, making it easy to re-order in a B2B e-commerce channel, as to ensure next day filter delivery and filter commissioning. ... brave new filter world.
The leap from a smart filter unit to a fully digitalized filter order process is less than a stone throw. A strong development of digitalized markets - also known as e-commerce is to be observed in a vast number of industrial sectors. A continuous increase of online transactions will eventually change the access to the filter market mid-term and fundamentally transform the market for air filters...


L19 - Liquid/Liquid Separation

Day: 24 October 2019
Time: 14:45 - 16:00 h
Room 1A

Session Chair:
Dr. Harald Banzhaf

Automatic water disposal for heavy duty and industrial applications – removal of hydrocarbons to ensure environmental protection

L. Spelter*, J. Neumann, MANN+HUMMEL GmbH, Germany

Modern fuel injection systems need to be protected from particles and water, causing wear on the system. A state-of-the-art fuel-water separator can reliably ensure a high purification by using multiple stages. The separated water is temporarily stored in collection space and needs to be drained regularly.

A fully automatic drain system removes the water when the sensor detects a certain level in the water collection chamber. Since the drained water is usually not collected automatically (e.g. in an extra tank), it should be cleaned prior to the release into the environment. A suitable adsorber removes the HC from the water phase.

The water that is separated by the fuel-water separator can be either clear or turbid. Whilst low additivated fuels usually lead to a clear water phase, an ultra-low sulfur diesel (ULSD) contains a high amount of additives and the drained water will be turbid due to the formation of a diesel in water emulsion. Why is this important? The solubility limit of diesel in water is reasonably low, approximately < 10 mg/l acc. DIN EN ISO 9377-2 H53 but an emulsion contains in average > 200 mg/l HC with levels up to > 2500 mg/l.

Activated carbon (AC) is the commonly used material in either systems that are already running on the street or are in a concept status, but only little evidence is found in the literature that activated carbon is actually suitable for this application. Experiments show that....

A methodology for estimating water droplet sizes and predicting filter performance in diesel fuel and lube oil applications

M.F. Alzoubi, John Crane Inc., USA; E. Barega*, T. van der Linde, INDUFIL BV part of John Crane Inc, Netherlands

A presence of even a slight amount of water in diesel fuel or in lube oil applications is considered one of the major hurdles to customers for maintaining high performance and long life expectancy for diesel engines and machineries. Predicting and quantifying water droplet size distribution in-diesel and in-lube oil mixtures has an essential and critical role on affecting filtration efficiency. In order to achieve high performance for diesel engines and lube oil applications, it is critical for filter suppliers and designers to be familiar with the water particle size distribution that is needed to select a proper filter elements.

Furthermore, ensuring high and an effective filtration performance and aiming for energy savings is another imperative element to consider when designing liquid-liquid filters. This paper presents a modelling approach for predicting water droplet sizes generated in an emulsion of water-in-diesel in horizontal pipe, in an orifice and in pumping flow applications using an empirical model such as Brauner's equation and a thermo-physical property software...

Best practice for liquid-liquid separation with cartridge coalescers

C. Rodewald*, D. Steinberger, PALL GmbH, Germany

The validation of a coalescer system for liquid/liquid separation and the proper use of this technology to improve the chemical processes can play an important role for a sustainable improvement in the production.

A new coalescer media on its own is not the sole solution for a well working separation process. It is a streamlined service concept starting from the definition of the task with the plant until the installed unit, which allows the operator to get the highest benefit for process reliability and performance.

This presentation will explain the typical workflow to validate and to implement the liquid/liquid cartridge coalescer technology; from the qualification of the application up to sizing and design of the housings including the calculation of the cost benefit to the plant.

The liquid/ liquid cartridge coalescer technology is applicable to a variety of applications. The presentation will illustrate the benefits, through different case studies, such as debottlenecking of the distillation columns, reducing of the footprint of settlers, increasing the productivity by reactor draining, extending the life of the chemical and absorption treatment systems...


L20 - Enhancement of Backwashing and Cake Filtration Performance

Day: 24 October 2019
Time: 14:45 - 16:00 h
Room 1B

Session Chair:
Dr. Harald Anlauf

Investigation about cohesion and adhesion in backwashing filtration based on penetrometry and tension tests

Y. Feith*, P. Morsch, H. Anlauf, H. Nirschl, Karlsruhe Institute of Technology (KIT), Germany; P. Ginisty, IFTS - Institute of Filtration & Techniques of Separation, France

Various equipment in liquid-solid separation (filter press, leaf filter, candle filter, rotary drum filter, nutsche filter, filtering centrifuge, cartridge filters and more) use filter cloth to retain particles as valuable particles or contaminants. An incomplete cake discharge and/or filter cloth cleaning after the filtration process causes yield losses, cycle time increase, irregular cake formation, increase cleaning liquors volumes, decrease of filter cloth lifetime. As cake filtration, washing or deliquoring, cake discharge and filter cloth cleaning/regeneration is a key step of the process cycle time. The choice of adapted operating conditions such as filter cloth characteristics, suspension pretreatment to modify sludge properties (e.g. granulometry, morphology), pressure, flow rate and further are necessary to decrease the duration of these operations to a minimum.

To describe the detachment behaviour, measurements of the cohesion in the filter cake are carried out on the basis of penetrometry. These measurements are accompanied by tensile tests, which aim at measuring the adhesion between tissue and the first particle layers. Framework of this investigation is to compare the adhesion between different filter cloth – particle combinations (weave type, fiber diameter, mesh size, particle size/shape/distribution and more) and the cohesion of different particle systems (particle size/shape/distribution and more). Based on this, the ad-/ and cohesion measurements shall be used to describe the regeneration through filter cake discharge on a laboratory filter candle test setup. Main task is to found out the mechanism of discharge based on strength measurements.

The presentation includes the presentation of the project, the measuring equipment and test materials used (filter fabric and particle system) as well as the current status of the project. In addition to the measurements of co-/adhesion, selected backwashing processes in the chamber and backwash filter will be demonstrated...

Separation and dewatering of biological microparticles from low concentrated suspensions by using the energy efficient thin film filtration

Z. Lam*, H. Anlauf, H. Nirschl; Karlsruhe Institute of Technology (KIT), Germany

The cake filtration is considered to be a low cost process for the continuous separation of inorganic and organic particles and also provides a very gently product treatment. The continuous sedimentation in the centrifugal field or the precoat filtration on a vacuum drum filter is currently used for the separation of biological microparticles. Separation in a centrifugal field with a low density difference between the particles and the continuous phase requires a high centrifugal force to achieve the desired separation efficiency. Therefore a large amount of energy is required to accelerate the suspension. Using a filter press would cause a long filtration time due to the compressible materials which are used here. Also a discontinuous batch filtration process of the filter press reduces the overall throughput of the filtrate which leads to a less efficient process. An alternative separation method for biological microparticles as well as compressible particles would be the cake filtration, but a high filter cake causes a high filter cake resistance and results in a reduction of the throughput.

The aim of this project is to develop a continuous thin film filtration method for the cake filtration...

Amelioration of phosphoric acid separation from phosphogypsum crystals using physical and chemical techniques

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

This study was carried out to enhance the filtration rate of phosphoric acid from calcium sulfate dihydrate (gypsum) under simulated conditions of phosphoric acid production using Dihydrate process. The applied techniques physical and/or chemical techniques. In industry, better filtration rate of phosphoric acid filtration from phosphogypsum means higher production as well as less capital and operation costs. Physical technique is related to decreasing the cake thickness via increasing rotation speed of filter under the standard applied vacuum. Chemical techniques lead to modification of crystals by different additives which added individually. This include but not limited to surfactants, polymers, aluminum bearing materials, oxidizing agents, blending of two phosphate ores, …..etc.

Phosphoric acid is produced using standard continuous unit simulates Dihydrate process of single tank reactor. The specific optimum conditions of reaction and crystallization of each phosphate ore was applied. To understand effect of additive from fundamentals point of view, induction time was measured under different supersaturation ratios. This is the time elapsed between the achievement of supersaturation ratio and the appearance of a solid phase. The results show that...


M5 -

Day: 10 March 2022
Time: 09:00 - 10:15 h

Nothing found.

Make your FILTECH visit easy and effective ! Choose papers of your interest.

0 / 25 selected

Complete Conference Programme (PDF)