McCabe-Thiele method stripping section

The McCabe-Thiele method employs the simplifying assumption that the molal overflows in the stripping and the rectification sections are constant. This assumption reduces the rectifying and stripping operating line equations to ... 

The McCabe-Thiele method assumes that the liquid on each tray and the vapor above it are in equilibrium, and that between the trays the molar composition of the down-flowing liquid and the up-flowing vapor are related by the operation lines, Eq. (3.3.16) for the rectification section and Eq. (3.3.18) for the stripping section (Figure 3.3.13). 

Figure 8.1.20. Vapor-liquid equilibrium curve, operating lines for enriching section and stripping section and construction of ideal stages and q Une for a feed consisting of vapor and liquid in a multistage distillation column having ideal equilibrium stages the McCabe-Thiele method.

The procedure in the stripping section is very similar. An equilibrium tie-line relates the reboiler concentration Xb with the vapor concentration 3 above the reboiler liquid. A line drawn from A 2 through establishes the liquid concentration Xi on the first plate in the bottom of the column. This procedure is repeated until the principal operating line is reached. Generally, only a part of a theoretical plate is required for the last step. This will have to be counted as a theoretical plate since partial plates are not practical in a real column. The separation called for in Example 6.8 and solved with the aid of the Ponchon-Savarit method shows a requirement of 4 theoretical plates in the rectifying section and 5 theoretical plates in the stripping section. The results are identical to those determined when the McCabe-Thiele method was utilized in Example 6.8 because the partial plates in both methods were counted as full plates. 

Combine material-balances information from the McCabe-Thiele graphical method with interphase mass-transfer considerations to determine the packed height of the rectifying and stripping sections of a continuous-contact binary distillation tower. 

The conventional McCabe-Thiele graphical method for analysis of binary mixtures was applied to determine the number of theoretical plates necessary for the separation, 11,3 theoretical plates are required for the rectifying section, and 9.4 for the stripping section. Thus a total of 20,7 theoretical plates are required. Since the value of chosen was 70 per... 

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