Solid-liquid, suspension separation, equipment selection

Depending on the task of the separation process, a large number of different types of equipment for the solid-liquid separation are available. Criteria for the selection are, inter alia, the filtration properties of the crop and the size of the particles, the suspension density, and the mode of operation, batchwise or continuous. Two main types of solid-liquid separations can be distinguished, cake forming filtration under pressure and centrifugation. In both cases, the crystals form a filter cake on a medium through which the mother liquor has to pass. The resistance is the rate-limiting step for the filtration and the characteristic property of the suspension. 

Preliminary Selections Assembling background information permits tentative selection of promising equipment and rules out clearly unsuitable types. If the material to be processed is a slurry or pumpable suspension of sohds in a liquid, several methods of mechanical separation m be suitable, and these are classified into settling and filtration methods as shown in Fig. 18-196. If the material is a wet solid, removal of hquid by various methods of expression should be considered. 

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