Cake Forming Filtration of Suspensions from the theory based analysis of test data to the reliable performance prediction of filters and filter centrifuges

Prof. Ioannis Nicolaou, Nikifos Ltd, Cyprus

The operation of Filters and Filter Centrifuges (in the following both types called Filters) like Nutsche Filters, Filter Presses , Belt, Drum, Disc and Pan Filters, Candle and Pressure Leaf filters, Vertical Basket, Peeler and Inverting Filter Centrifuges involves cake forming filtration of suspension with the optional steps of cake deliquoring and cake washing. There is a great need for a reliable filter selection, a reliable design of the selected filter and an optimal operation of such filters for different setting parameters but also under consideration of changes of the suspension behavior. This task can only be accomplished by the use of physically based and practice oriented (half empirical) mathematical models which include parameters with a physical meaning and not depending on the filter settings (so called material specific parameters). Such equations are the basis for the characterization of the suspension filterability as well as for the washing and deliquoring efficiency through analysis of experimental data on a laboratory or/and pilot scale. Further more such equations are a guide for a systematic experimental procedure with minimal number of experiments and the basis for 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 presented. 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, which are necessary for the determination of the efficiency parameters, will be discussed. The theory based analysis of the experimental data with the use of practice oriented software will be presented. The user friendly data correction with the help of theory based graphs as very important part of the data analysis and the reliable determination of the efficiency parameters will be demonstrated by presenting test series with different suspensions. Finally, based on the reliably determined efficiency parameters for the cake formation and for the optional steps of cake washing and cake deliquoring (main task of the test data analysis modules of the programs) the performance calculation for Filters (FILOS Software) and Filtering Centrifuges (CENTRISTAR Software) for different material and setting parameters will be demonstrated.

Session: K2 - Keynote Lecture II
Day: 13 March 2018
Time: 14:45 - 16:00 h

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