Selection of Filtration Equipment

It may be difficult to choose the right filtration equipment for a crystallization process. The selection of filtration equipment involves balancing the process specihcations and objectives with the capabilities and characteristics of the various equipment alternatives. Wakeman and Tarleton [49] provide guidelines for the selection of hltration equipment. Important process-related factors are the slurry character, production throughput, process conditions, performance requirements. 

For estimating filtration rate (therefore, operating pressure and size of the filter), washing characteristics, and other important features, small-scale tests such as the leaf or pressure bomb tests described earlier are usually essential. In the conduct and interpretation of such tests, and for advice on labor requirements, maintenance schedule, and selection of accessory equipment the assistance of a dependable equipment vendor is advisable. 

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 shiny or pumpable suspension of sohds in a hquid, several methods of mechanical separation may be suitable, and these are classified into setfiiug and filtration... 

Some asceptic processes are developed initially in non-sterile facilities and need to be re-designed to produce a sterile product. Thus the type, size and material used for vessels, piping and tubing (particularly product contact surfaces), the selection of appropriate equipment for each unit process i.e. mixing, filtration, filling, etc., the use of disposable or re-usable equipment, the order of unit operations, the fluid transfer between unit operations and... 

Testing procedures were established for each vendor selected for on-site demonstration of filtration equipment. These procedures were based on the need for testing data to properly complete the final equipment specifications and purchase justification. 

The type of filtration equipment you select for use depends upon which of the two components, the solid or the liquid, you are trying to isolate. In i. general ... 

Theory alone, however, can never be the basis for selection of a filter. Filtration belongs to the physical sciences, and thus conclusions must be based on experimental assay. It is, however, helpful in understanding why a slurry is more suitable for one design of filtration equipment than another. Methods of optimization in the field can also be predicted by having a background in the theory. 

For a particulate application involving SLS, how to choose the best equipment, to use batch or continuous operation, which filter medium to select, and what is the optimum operating conditions are concerns of engineers. Although theories are available for some SLS operations, solutions for equipment selection, process design, and optimization are still very much dependent on test and experience, and are frequently qualitative or semi-qualitative. In this section, strategy and decision networks for selection of SLS equipment, introduction of filter media, centrifugal pumps for filtration operation, and selection of filter aids by cycle analysis will be discussed. 

Appropriate selection of filter media is one of the most important factors to ensure efhcient performance of filtration equipment. The filtration performance requirements are apphcation specific and may include (Cheremisinoff et al. 1983) ... 

Because the influence of gravity is so important to most filtration operafimis, the second classification basis is used in this chapter. The operating principles and important features of filtration equipment are described in diis chapter with the intent of providing the reader a background in the versatility and selection opticms available. 

Final filtration equipment selection should be based on the ability to meet all objectives of the application within economic constraints. 

Filtration may also serve as the preparatory step for the operation following it. The latter stages may be drying or incineration of solids, concentration or direct use of the filtrate. Filtration equipment must be selected on the basis of their ability to deliver the best feed material to the next step. Dry, thin, porous, flaky cakes are best suited for drying where grinding operations are not employed. In such cases, the cake will not ball up, and quick drying can be achieved. A clear, concentrated filtrate often aids downstream treatment, whereby the filter can be operated to increase the efficiency of the downstream equipment without affecting its own efficiency. 

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