1 0.9 0.8 0.7 0.6 benzene mole fraction in vapor, y 0.5 0.4 0.3 0.2 0.1 0 o 0.1 0.2 0. 0.8 0.9 0.3 0.4 0.5 0.6 0.7 benzene mole fraction in liquid, X 1 Problem 1 A tray tower is to be designed to continuously distill 450 lbmol/h of a binary mixture of 60 mol% benzene and 40 mol% toluene. A liquid distillate and a liquid bottoms product of 95 mol% and 5 mol% benzene, respectively, are to be produced. The feed is preheated so that it enters the column with a molar percent vaporization equal to the distillate-to-feed ratio. Use the McCabe-Thiele method to compute the following, assuming a uniform pressure of 1 atm (101.3 kPa) throughout the column: (a) Minimum number of theoretical stages, Nmin; (b) Minimum reflux ratio, RD,min; and (c) Number of equilibrium stages N, for a reflux-to-minimum reflux ratio, Rp/RD,min of 1.3 and the optimal location of the feed stage. The relative volatility of benzene-tolune is a= 2.45. The VLE equilibrium curve can be generated by plotting y Vs x from Ox = 1+ (a 1)x