Stripper theoretical stages, examples

In this chapter we will discuss single theoretical stage Bubble-Point and Dew Point calculations and give examples as to how these can be used in our work. Then weTl discuss the use of the Absorption Factor and Stripping Factor chart, which can be used to design distillation towers. In order to use this chart in that way it is necessary to consider a distillation tower as two separate towers. The top of the tower is considered an absorber. The chart is then used in a different way to design the lower part of the distillation tower as a stripper. 

In general, distillation columns should be operated at a low pressure. For example, Fig. 3.3 shows an isobutane-normal butane stripper. This fractionator is performing poorly. A computer simulation of the column has been built. The column has 50 actual trays. But in order to force the computer model to match existing operating parameters (reflux rate, product compositions), 10 theoretical separation stages (i.e., 10 trays, each 100 percent efficient) must be used in the model. This means that the trays are developing an actual tray efficiency of only 20 percent. 

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