26.8-6. 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 components as calculated. The feed is below the boiling point, so that q = 1.1. The operating reflux ratio is 3.0. Assume that Raoult's law applies and use vapor-pressure data from Problem 26.8-3. 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 = 27.77 mol/h, XAD = 0.95, XBD = 0.05, XCD = 0, XDD =0; W = 72.222 mol/h, XAW = 0.0500, XBW 0.2577, xcw=0.2077, XDW = 0.4846;