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Unformatted text preview: e in the bottoms = 0.004, giving 99.6 mol% toluene in the bottoms. The overhead vapor contains 0.449 mole fraction benzene. By material balances, F = 125 = D + B and 0.36F = 0.449D + 0.004B, D = 100.0 and B = 25.0 kmol/h. Exercise 7.18 (continued) Analysis: (b) (continued) Exercise 7.18 (continued)
Low-concentration Region Exercise 7.19
Subject: Normal and abnormal operation of a distillation column separating a methanol water mixture at 101 kPa. Given: Column with 7 theoretical plates, a total condenser, and a partial reboiler. A feed of 100 kmol/h of 50 mol% methanol in water is sent to plate 3 from the bottom. During normal operation, distillate is 90 mol% methanol and bottoms is 5 mol% methanol, with a reflux rate of 1 mole per mole distillate. During abnormal operation, the following data are obtained: Stream kmol/h mol% methanol Feed 100 51 Bottoms 62 12 Distillate 53 80 Reflux 94 Vapor-liquid equilibrium data are given at 101 kPa, where methanol is the more volatile species. Assumptions: Constant molar overflow. F...
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