Continuous filtration without gas throughput — using membrane filter media: A feasibility study

Abstract

During the process of the cake forming wet filtration with conventional filter cloths two disadvantages are inevitable. These are: (a) the high gas throughput during the dewatering of the filter cake and (b), the passing through of particles at the beginning of the cake formation. Depending on the application there are high costs to reach a sufficient dewatering pressure difference in spite of high air consumption or to reach a sufficient clarity of the filtrate due using thickeners or clarifying filters. By using microporous membranes as membrane filter cloths a process of cake forming filtration (with a following filter cake dewatering) was developed with which the gas throughput and the passing through of particles can be prevented completely. Analogous to conventional (woven) filter cloths these membranes can be used on conventional filter apparatuses (eg drum filters). According to the filtration product almost the same rates of mass throughput and moisture content have been reached with the membrane filter cloth as with conventional filter cloths.