ABSTRACT
Filtration is probably one of the oldest unit operations. The old forms of filtration by straining through porous materials were described by the earliest Chinese writers. A gravity filter used in a chemical process industry was described in an Egyptian papyrus which has its origin in about the third century anno domini. In vacuum operations after filtration is completed, the vacuum may be left on in order to remove some of the liquid. Similarly, in pressure filtration, compressed gas may be used to blow out a portion of the liquor. Filtration of non-Newtonian fluid-solid mixtures is a subject of great importance in such diverse fields as petrochemical and food processing industries. All the equations of non-Newtonian filtration reduce to the conventional filtration equations for Newtonian fluids by putting the flow behavior index N as unity and the fluid consistency index K as the viscosity y of Newtonians.
