Solid-liquid mixing equipment selection

SELECTION, SCALE-UP, AND DESIGN ISSUES FOR SOLID-LIQUID MIXING EQUIPMENT 573... 

Binder liquid should wet the solid particles and not the interior walls or the mixing tools of the equipment. If parts of the mixer are wetted, build-up occurs which is difficult to remove. Different spray patterns are available with commercially available single or two phase nozzles (Fig. 7.22c and 7.23) and a suitable pattern should be selected to assure that liquid impinges only on the moving powder. Since the spray pattern depends critically on the cleanliness of the orifice area, as mentioned before, nozzles must be drip free and installed such that they remain clean or are blown free by the action of atomizing gas. This is particularly important for low capacity nozzles which are often preferred because the binder liquid should be always completely ab-... 

For gas-liquid-liquid reactions equipment similar to that used for liquid-liquid reactions are employed. The hydrodynamics in these reactors is extremely complex because of the three phases and their convoluted interactions. An example is the grazing behavior of small solid particles enhancing mass transfer at gas-liquid interfaces. The scale-up from laboratory to the production site thus poses numerous problems with respect to the reactant s mixing, temperature control (heat removal), catalyst selectivity, and its deactivation [1]. The performance of such processes can be predicted analytically only to a limited extent for reactors with well-defined flow patterns. 

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