Cake formation and flux decline in centrifugal filter basket

摘要

Cake formation and filtration flux in a centrifugal filter basket are simulated using a Lagrangian-Eulerian model. The particle migration in the filter basket is analyzed based on the Newton's second law of motion and the hindered settling theory. The variations of particle concentration profiles in the filter basket under various rotating speeds are then simulated and discussed. The sedimentation effect of particles may result in a heterogeneous filter cake, i.e., more larger particles exist near the cake bottom while more smaller ones near the cake surface. An increase in rotating speed causes the filter cake to grow quicker and to be more heterogeneous. Based on the Kozeny-Carman equation, the average specific filtration resistance of cake can be evaluated, and the filtration flux can then be calculated by the basic filtration theory. The filtration flux increases with increasing rotating speed due to a higher filtration pressure. Centrifugal filtration experiments are carried out using a particulate sample, Talc. The simulated results of particle size distribution in cake, the average specific filtration resistance of cake and the filtration flux agree very well with the experimental data.