(559a) A New Method for Analyzing and Designing Filter Press Separations

Raymond Collins, Engineering and Process Sciences, The Dow Chemical Co., Midland, MI

A non-traditional model describing the separation of particulate
solids from a liquid suspension by pressure-driven flow through a permeable
barrier has been successfully applied to the design of several filter press
applications.  This flow model was derived
by applying fundamental physical principles to the unsteady, mixed-phase system
represented by cake filtration with a filter cloth.  The analysis has proven suitable for operating modes employing both constant applied pressure
and constant feed flow rate.  The design
procedure uses small-scale experiments to determine a
governing permeability function, which has a reproducible, characteristic dependence on the collected volume of filtrate with parametric dependence on the
properties of the solids, liquid and filter cloth.  The experimental method and various lab-scale
test filters will be described, and the utility of this method will be
demonstrated for a few common, large-scale applications in chemical
processing.   These include the removal of polymer fines from
wastewater, the deliquoring of biomass from a concentrated
sediment of fermentation broth, and the isolation and washing of micron-sized
solids used to manufacture energy materials.