Dynamic Loading of Porous Filters with Fine Particles

Abstract

Transient filtration of fine particles from an air stream is studied analytically. Transport of particles within the porous filter is viewed as a convective-dispersive phenomenon. Collector-particle and particle-particle interactions within the filter are considered and the reentrainment of deposited particles is assumed negligible compared with particle attachment. Relations governing the particles’ deposition and penetration, as well as filter’s resistance and performance are presented. These quantities are dependent upon physical properties of the porous filter (e.g. solidity, thickness), deposition coefficients and also dimensionless parameters like Peclet number and interception parameter. Additionally, an expression allowing the estimation of the clogging time of the filter is also presented. The models presented here are both useful to filter design and control of filtering operations.