Stagewise contacting

The internal devices may be gnoaped into two general categories tray-type and pecking-fype. The former provides a stagewise contacting mude whereas the latter provides a counlerearrem mode. In the present section the tray-type devices will be considered. 

Contacting Columns. A tall cylindrical column or tower can be filled with packing for continuous contact of two or more phases or fabricated with a number of trays at fixed distances apart for stagewise contact operation. Such columns, either alone or in series, are commonly specified for separations-in gas absorption, distillation, extraction, and humidification. 

The equilibrium curve is plotted in Fig. 7.3-5 from the terminal points ot each experimentally determined tie line on the triangular diagram.The use of Fig. 7.3-5 in determining either the number of theoretical stages needed (for stagewise contact) or the number of transfer units needed (for packed column contact) will be discussed shortly. 

Stagewise contact with controlled coalescence redispersion cycles Tray column Pulsed sieve column. Pulsed Mixer-Settler-cascade, Extraction tower with controlled cycle Scheibel column, ARD-Extractor, Leisibach column, Mixer-Settler cascade ... 

Stagewise contact. In this category are included those arrangements of equipment where solvent and mixture to be separated are intimately contacted, allowed to approach equilibrium, and separated. The operation may then be repeated and with a variety of flowsheets. 

In this chapter only stagewise contact with single solvents is considered. 

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