In the 1970’s, chemical operations that I have been exposed to used acetone and benzene for the main slurry solid-liquid separation process as well as for cleaning. In the 1980’s, there was a push to minimizing solvent use and research was looking more towards using water as the process liquid, but you still had open filter presses, rotary drum filters where the entire plant was “white” from titanium dioxide or pharma stearates. Fast forward to the present and we all know that processes remain open with filter presses, vacuum filters and centrifuges. Our job these days is to find solid-liquid separation process solutions that can be contained contain for high solids slurries (greater than 10% solids) during filtration, cake washing and dewatering/drying. The discussion in this Tech Brief looks at batch and continuous operations.

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