A Six Sigma Approach to Evaluating Vacuum Filtration Technologies

HEADNOTE

The appropriate testing procedures help direct the selection of vacuum filtration equipment and ensure optimum equipment operation.

Solid-liquid separation can be accomplished by pressure or vacuum filtration

in a batch or continuous mode. Generally, following filtration, the cake must be washed and subsequently dried to specifications. The technology choice process depends on a wide range of parameters, including the nature the solids (crystal size and distribution, shape and type), the liquids (temperature, viscosity and nature) and the process itself. This article examines the use of a continuous-indexing vacuum belt filter (CI-VBF) as a replacement for manually operated filter presses and offers insight into one plant's technology-selection process.

A specialty chemical plant was using several filter presses to produce various high-valued products in the form of thin filter cakes. Each unit contained 136 plates with a total filter area of 4,400 ft^sup 2^ (440 m^sup 2^). Unfortunately, the plant was experiencing a wide range of operating and process problems: