FILTRATE FLUX IN CROSS-FLOW MICROFILTRATION OF DILUTE SUSPENSION FORMING A HIGHLY COMPRESSIBLE FOULING CAKE-LAYER

The crossflow microfiltration characteristics of dilute suspension, wh ich produces a highly compressible fouling cake-layer and/or a highly viscous filtrate, is studied under constant pressure. With the filtrat ion conditions within a critical level, medium filtration at an earlie r stage ceases, and crossflow microfiltration follows the principle of thin-cake filtration after operation begins. An equation for flux, wh ich relates the cake resistance to a number of operational variables, is determined for the thin-cake filtration process by introducing a co ntrolling parameter composed of the shear stress exerted at the cake s urface and the coefficient of constant-pressure filtration. On the bas is of an empirical correlation of the flux-controlling parameters, the effects of both cake-compressibility and filtrate-viscosity on the fl ux are evaluated.