Pareto Profile Benchmark for Kinetics of Filtration and Extent of Dewatering of Fine and Colloidal Suspensions

Abstract

The time scale of the process and the extent of dewatering are principal performance measures of high pressure filtration of fine and colloidal suspensions which give rise to compressible filter cakes. Analysis of numerous filtration tests conducted under a wide range of suspension chemistry and process conditions suggests that it is not possible to improve the two performance measures simultaneously. As stipulated by the Pareto optimum, any improvement in the filtration kinetics can occur only at cost of reducing the extent of moisture removed from the filter cake and vice versa. The unique Pareto profilesthe curve of filtration kinetics versus extent of dewaterings is the fingerprint of the filtration behavior of a particulate solid in suspension. Accordingly, any physical-chemical scheme, which purports to improve the overall filtration process, should be benchmarked against the Pareto curve.

Enhancement of Colloidal Filtration: A New Combined Approach Based on Cake and Suspension Destabilization

“…On the other hand, flocculation leads to rapid filtration with the penalty of higher cake moisture. It is critical to assess the extent of moisture removal along with the filtration time, as it is observed that it is not easy to improve the extent of dewatering and the kinetics of the filtration process simultaneously in batch filtration carried until equilibrium by dispersion and flocculation of colloidal systems . One physical route for enhancing the performance of the filtration process is to follow methodologies in which cake formation over the membrane is prohibited.…”