8 653 11955 19699 7680 12019 mole fraction feed

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Unformatted text preview: 0 1.000 Bottoms 0.0053 0.9947 1.0000 Use the McCabe-Thiele method, based on methanol mole fractions, to find the number of equilibrium stages needed. The slope of the rectifying section operating line is given by Eq. (77). L/V = R/(R + 1)=0.947/(1.947)=0.486. This line intersects the 45o line at x = 0.915. The slope of the stripping section operating line is given by Eq. (7-12). L / V = VB + 1 / VB = (1.138 + 1)/1.138 = 1.88. This line intersects the 45oi line at x = 0.0056. The McCabe-Thiele diagram is given below in two parts to achieve accuracy. From the two parts of the diagram, it is observed that the two operating lines do not intersect on the q-line. This is probably because the assumption of constant molar overflow is not valid and the operating lines have some curvature. Assuming the feed stage in the actual column is near the optimal location, the questionable McCabe-Thiele diagram gives 5 equilibrium stages in the stripping section, one of which is the partial reboiler, and 4.2 equilibrium stages in the rectifying section. Thus, the total equilibrium stages in the colu...
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This note was uploaded on 09/08/2008 for the course CHE 244 taught by Professor Selebi during the Spring '06 term at Lehigh University .

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