(110e) A Treatise of Filter Cake Washing Mechanisms In Pressure and Vacuum Filtration Systems

During many chemical and pharmaceutical process operations, cake washing is required since no filter system can remove all of the mother liquor by pressure or vacuum dewatering only.  The need for cake washing to produce a “clean cake” for further processing, drying or disposal can be for several reasons including the removal of the mother liquor, exchange of solvents, dissolution of soluble components and the displacement of insoluble contaminants. 

The topic of “how to most efficiently wash the cake” is one that many process engineers struggle with when considering the various techniques available to meet the economic, production and quality requirements of the operation.  Chemical engineering textbooks are notoriously shy on the subject and such information that is available is frequently lost in a host of theoretical equations.  This article introduces pragmatism into cake washing theory and will help to guide engineers during their decision-making processes.