Displacement Washing of Filter Cakes With a Fine Particle Top Layer

Abstract

Displacement washing of filter cakes is a critical process in various filtration applications and the presence of a top layer of fine particles from preceding cake filtration may influence washing efficiency. To investigate the effect of such a top layer on the displacement washing process, filter cakes with solid volume fractions ranging from 15 % to 33 % are formed from crushed, irregularly shaped limestone particles of about 10 to 250 µm to minimize or induce segregation effects due to sedimentation superimposed on cake filtration. The structural properties of the filter cakes are measured using X-ray microscopy and dynamic image analysis. To predict the influence of cake structure on displacement washing, an advection–dispersion model is employed. Comparison between prediction and experimental data shows good agreement, highlighting the impact of cake structure on washing efficiency and providing valuable insights for optimizing displacement washing processes in industrial applications.