11 for benzene and 9213 the result is component kmolh

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Unformatted text preview: d 92.13. The result is: Component kmol/h Mole fraction Benzene 69.65 0.44 Toluene 88.57 0.56 Total: 158.22 1.00 For a distillate of 97 wt% benzene, the mole fraction for benzene, the more volatile of the two components, is, 97 7811 . xD = = 0.974 97 3 + 78.11 92.13 With a reflux ratio of 3.5, from Eq. (7-7), the slope of the rectifying section operating line is, L/V = R/(1 + R) = 3.5/4.5 = 0.778 The q-line is a horizontal line at y = 0.44. For 14 plates with 50% efficiency, the column has the equivalent of 7 equilibrium stages + 1 for the partial reboiler. The McCabe-Thiele construction is shown on the next page, where it is seen that it is possible to obtain the desired distillate composition. (b) and (c) From the McCabe-Thiele diagram, the mole fraction of benzene in the bottoms is xB = 0.24. As a weight fraction, this corresponds to, 0.24(78.11) = 0.211 weight fraction or 21.1 wt% benzene 0.24(7811) + 0.76(92.13) . Compute the distillate rate by overall molar material balances. Overall total ma...
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