ation. 11.7-6. Distillation of Multicomponent Alcohol Mixture. A feed of 30 mol % methanol (A), 20% ethanol (B), 15% n-propanol (C), and 35% n-butanol (D) is distilled at 101.32 kPa abs pressure to give a distillate composition containing 95.0 mol% methanol and a residue composition containing 5.0% methanol and the other com- ponents as calculated. The feed is below the boiling point, so that q = 1.1. The oper ating reflux ratio is 3.0. Assume that Raoult's law applies and use vapor-pressure data from Problem 11.7-3. Calculate the following: (a) Composition and amounts of distillate and bottoms for a feed of 100 mol/h. (b) Top and bottom temperatures and number of stages at total reflux. (Also, calculate the distribution of the other components.) (c) Minimum reflux ratio, number of stages at R = 3.00, and feed-tray location. Ans. (a) D=27.778 mol/h, XAD = 0.95, XBD = 0.05, XCD = 0, XDD = 0; W = 72.222 mol/h, xaw 0.0500, xgw = 0.2577, xcw=0.2077, xpw = 0.4846; = (b) 65.5°C top temperature, 94.3°C bottom, N = 9.21 stages, XCD 3.04 X 10-5, xDD = 8.79 x 10-7 (trace compositions): = (c) R = 2.20, N = 16.2 stages, N, = 7.6, m N, 8.6, feed on stage 8.6 from top = " uid feed at its