500675 Chemical and Equilibrium Separation Processes Workshop Four Question 1 (Example 12 on Page 49 of the Lecture Notes) A two-phase feed of 50 mol% benzene in a binary mixture with toluene with a specific enthalpy that is intermediate between the specific enthalpy of the saturated liquid and vapour is feed to a distillation column operating at 1 atm. The distillate is to be at least 96 mol% benzene and the bottom concentration less than 6 mol% benzene. Assuming that each stage is an equilibrium stage, calculate the total number of stages and the location of the feed to achieve the duty if the reflux ratio is to be 1.3 x the minimum. Further, calculate the recovery of toluene into the bottoms product. Graphical equilibrium data given in Figure 1. Page 1 of 1 0.9 0.8 0.7 0.6 Mole fratction of benzene in vapour, y 0.5 0.4 0.3 0.2 0.1 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Mole fraction of benzene in liquid, X Figure 1. Equilibrium curve of benzene-toluene system at 1 atm