Centrifuges solid-liquid separation

Crystals suspended in liquors emerging from crystallizers are normally passed to solid-liquid separation devices such as gravity settlers or thickeners that may subsequently feed filters to remove yet more liquid prior to drying. Here the transport processes of particle motion and the flow of fluids through porous media are important in determining equipment size, the operation of which may be intensified by application of a centrifugal force. 

Zeitsch, K., 2000. Centrifugal Filtration. In Solid-liquid separation, 4th edition. Ed. L. Svarovsky. Oxford Butterworth-Heinemann. 

A selection guide for sedimentation centrifuges by Lavanchy et at. (1964), which includes other types of solid-liquid separators, is shown in Figure 10.19, adapted to SI units. 

Hydrocyclones are used for solid-liquid separations as well as for solids classification, and liquid-liquid separation. It is a centrifugal device with a stationary wall, the centrifugal force being generated by the liquid motion. The operating principle is basically the same as that... 

Extracellular enzyme Cell removal (solid liquid separation) Centrifugation Filtration... 

Figure 4.15. Solid-liquid separation in industrial scale using centrifugation in continuous mode (A) or passage of the suspension through manifolds such as those shown in (B) mounted with filter cartridges (C) designed for tangential or cross-flow of liquid suspension. Panel A NIH Fredrick facility, with permission Panels B and C Milipore, MA, with permission.

Solid/liquid separation is usually required at the interface of the primary and secondary stages to allow optional upgrading of the crude coal liquids of the primary liquefaction stage, by removing mineral matter, unreacted coal, heavy products, and catalysts (111, 112). Distillation, anti-solvent extraction, and centrifugation have been conventionally employed in liquefaction processes (113, 114). 

The relative suitability of the common kinds of solid-liquid separation equipment is summarized in Table 11.3. Filtration is the most frequently used operation, but sedimentation as a method of pretreatment and centrifugation for difficulty filterable materials has many applications. Table 11.15 gives more detail about the kinds of filters appropriate to particular services. 

The use of centrifugal fields in chemical processing dates to the beginning of the industry with such physical transport operations as pumping, compression, and solid/liquid separations. Extending this use into mass and heat transport operations... 

Crystal morphology (i.e., both form and shape) affects crystal appearance solid-liquid separations such as filtration and centrifugation product-handling characteristics such as dust formation, agglomeration, breakage, and washing and product properties such as bulk density, dissolution kinetics, catalytic activity, dispersability, and caking. 

Clear-liquor advance is used for two purposes (1) to reduce the quantity of liquor that must be processed by the solid-liquid separation equipment (e.g., filter or centrifuge) that follows the crystallizer, and (2) to separate the residence time distributions of crystals and liquor. The reduction in liquor flow through the separation equipment can allow the use of smaller equipment for a fixed production rate or increased production through fixed equipment. Separating the residence time distributions of crystals and liquor means that crystals will have an average residence time longer than that of the liquor. This should, in principle, lead to the production of larger crystals, but because the crystallizer is otherwise well mixed, the crystal population density will have the same form as that for the MSMPR crystallizer (Eq. (54)). 

Solid liquid separation. The techniques available for the separation of sohds and hquid include filtration, centrifugation, and sedimentation. 

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