Question

(a) A distillation column is designed to separate an acetone/acetic acid mixture at101.3 kPa. The feed has a composition of 40 mol% acetone and enters the column at 1300 mol

h-1 at its bubble point. The recovery of acetone is 90%, and the distillate composition is required to be 95 mol % acetone. The column operates at a reflux ratio of R=1.20. The vapour-liquid equilibrium (VLE) molar compositions are given in Table Q1. Find distillate and bottoms molar flow rates and bottoms molar composition.[6 marks] (b) Using McCabe-Thiele method, determine the number of theoretical stages required and the feed plate location for the process described in (a). (c) A batch distillation of an acetone/acetic acid mixture containing 50 mol% acetoneends up with the half of the initial amount of liquid remaining with 25 mol%acetone. Using Rayleigh equation given below, estimate the average relativevolatility of the mixture (a).[5 marks] \begin{array}{l} \text { Operating line for rectifying section }\\ y_{n+1}=\frac{R}{R+1} x_{n}+\frac{x_{D}}{R+1} \end{array} \begin{array}{l} \text { Rayleigh Equation }\\ \ln \frac{L_{1}}{L}=\frac{1}{\alpha-1}\left(\ln \frac{x_{1}}{x}+\alpha \ln \frac{1-x}{1-x_{1}}\right) \end{array}

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