A feed containing 50 mol% A and 50 mol% B is fed to a distillation column. A reflux ratio of 1.3 is maintained. The overhead product is 95% A and the bottoms is 5% A. Find the number of theoretical stages and the optimum feed stage. Assume that a total condenser is used. The column is to operate at 1 atm. Equilibrium data is given as:
Equilibrium Data at 1 atm:
0.0 0.1 0.2 0.3 0.5 0.6 0.7 1
0.0 0.3 0.5 0.7 0.85 0.9 0.95 1
Enthalpy-Concentration Diagram:
Enthalpy (kcal/kmol) Mol frn A
Saturated Liquid Saturated Vapor
6900 15600 0.1
6200 15100 0.2
5700 15000 0.3
4900 4600 0.4
4600 14100 0.5
4000 13800 0.6
3800 13400 0.7
3500 12800 0.8
3200 12100 0.9
3000 11400 1
2800 9700