Solid/liquid separation equipments filters

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. 

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)). 

Figure 5.2 Flowchart for the selection of solid/liquid separation equipment the region highlighted in the top half of the flowchart is performed by the equipment selection module of FDS (Filter Design Software, 2005).

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. 

The Air Quality Control Systems (AQCS) using lime/limestone wet scrubbing have three basic types of chemical process equipment (1) scrubbers, (2) reaction tanks, and (3) solid-liquid separators, in addition to several auxiliary pieces of equipment such as pumps, demisters, and reheaters. The SO2 in the flue gas is transferred into the liquid in the scrubber, the sulfur in the liquid is converted to solid calcium sulfite, and calcium sulfate in the reaction tanks and solid calcium sulfite and sulfate are separated from the liquid and disposed from the solid-liquid separators such as clarifiers, vacuum filters, and ponds. 

The simplest type of extraction equipment is the stirred tank, coupled with a solid-liquid separation step such as a screen, filter, or centrifuge to separate the marc from the extract. This equipment is readily available in a wide variety of sizes and can be operated as a single-batch extractor or run in series in a countercurrent mode as shown in Figure 11.6. 

Solid-liquid separation systems generally consist of four stages including pretreatment, solid concentration in thickeners, solid separation in filters or centrifuges, and post-treatment by expression and washing operations. There are different types of SLS equipment served for different functions in relation to the four stages. Product specification, characteristics of solid-liquid suspension, solid settling velocity, rate of cake... 

As shown in Fig. 11.1-1, the solids—liquid separation device is the link between the solids formation equipment and the diying operation, Thus, predictable and reliable operation is essential in this stage of the processing sequence. Continuous or baich-automatic centrifuges nad continuous vacuum filters are typically used to recover solid material from continuous crystal I ization operations. Many factors are considered in [ha final selection of the device. In any case, an equipment testing program is always essential to determine the capacity and performance of solids separation equipment. 

The cold frit is crushed in equipment which is preferably totally enclosed to prevent personal contact with the irritant alkaline dust. Leaching is then carried out with water to remove sodium silicate and excess sodium hydroxide. About 7 tons of water per ton of zircon are appropriate, this quantity being divided between several successive leaching operations. Solid-liquid separation is by decantation between each leach. The sodium zirconate is finally filtered off in a fairly dry condition. It is advisable not to use a larger excess of water or peptization of colloidal zirconium com-... 

Abstract Industrial filtration operations involving textile filter media are found in the production of countless items that we encounter in our everyday lives, and yet more operations are engaged in protecting the environment. The chapter attempts to provide a brief overview of the filtration mechanisms that are involved both in industrial dust collection and solid-liquid separation processes, and the equipment types that are engaged in each. The chapter also describes the types of textile filter media that are employed in the various operations, their component strengths and weaknesses, and some of the finishing treatments that are applied to enhance their efficiency. 

Grimwood C., 2005. Filtering centrifuges, in Solid/Liquid Separation Scale-up of Industrial Equipment , Eds. R.J. Wakeman and E.S. Tarleton, pp. 314—374, Elsevier, Oxford. 

Particle characterization, i.e. the description of the primary properties of particles in a particulate system, underlies all work in particle technology. Primary particle properties such as the particle size distribution, particle shape, density, surface properties and others, together with the primary properties of the liquid (viscosity and density) and also with the concentration and the state of dispersion, govern the other, secondary properties such as the settling velocities of the particles, the permeability of a bed or the specific resistance of a filter cake. Knowledge of these properties is vital in the design and operation of equipment for solid-liquid separation. 

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