Dynamic Crossflow Filtration

Abstract

Abstract Dynamic crossflow filtration increases membrane performance through the use of membrane shear rates that are much higher than in conventional crossflow filtration. The production of these high shear rates requires specific modules with metal disks or rotors rotating at high speed near fixed membranes or rotating or vibrating membranes. The advantages and drawbacks of dynamic crossflow filtration will be discussed and currently available pilots and industrial dynamic filtration modules will be described. Specific methods for calculating the shear rate at membranes, which is the key factor governing permeate flux, will be presented for various types of modules. Recent applications of dynamic filtration published in the scientific literature, together with industrial case studies and comparisons with conventional crossflow will be reviewed. These systems can be advantageous for end‐of‐pipe treatment when the goal is to maximize retentate concentration in order to reach at least 65% of solid concentration. In pharmaceutical and biotechnological applications, where a high purity is required, the higher membrane selectivity of dynamic filtration (better solute transmission in microfiltration and higher microsolute rejection in nanofiltration and reverse osmosis) is an important asset. Industrial strategies of manufacturers of modules, New Logic Research (CA, USA), which has sold over 376 industrial vibrating modules; Bokela (Germany), which produces the rotating disk Dyno filter; and Metso Paper (Finland), which sells the Optifilter with rotors between, will be summarized.