In the production of diethyl ether, assume that it is necessary to purify a stream at 1500 kPa containing 75 mol% diethyl ether, 20 mol% ethanol, and 5 mol% dimethyl ether.

Assume that the UNIQUAC model adequately predicts the thermodynamics of this system.

1. Use the residue curve plotting routine on your simulator to plot the residue curves.

2. Suggest a method for separating this mixture into three relatively pure components.

3. How would your answer to Part (b) change if the stream contained 85 mol% diethyl ether, 10 mol% ethanol, and 5 mol% dimethyl ether?

4. Examine the effect of changing the pressure of the distillation columns. Suggest a much simpler method for achieving the necessary separation.