Question

Separation of Acetone and Ethanol

A distillation column with a total condenser and partial reboiler is separating acetone and ethanol (equilibrium data is provided in the table below). The feed is 70 mole% acetone, flows at 1000 mol/h, and is a superheated vapor for which one mole of liquid must be vaporized on the feed plate to cool four moles of feed. We desire a bottoms composition of 5 mole% acetone and a distillate composition of 90 mole% acetone. The column operates at 1 atm. The equilibrium data is given in the table below. Answer the following questions.

a) What is the minimum number of stages needed for this separation (i.e. total reflux)?

b) What is the minimum reflux ratio?

c) If R = 2R_min, find the optimal feed stage and the number of stages if the column efficiency is 75%.

Acetone-Ethanol Equilibrium Data at 1 atm in terms of Acetone concentrations:

xA	0.1	0.15	0.2	0.25	0.3	0.35	0.4	0.5	0.6	0.7	0.8	0.9	1.0
yA	0.262	0.348	0.417	0.478	0.524	0.566	0.605	0.674	0.739	0.802	0.865	0.929	1.0

Answer 1