In the production of diethyl ether, it is necessary to purify a stream of equimolar diethyl ether and water that is available at 1500 kPa. Suggest a method for achieving this separation. Use the UNIQUAC model for the K-value. Would your answer be different if, for example, only 99 mol% purity were needed instead of 99.9 mol%? What do you learn and how does your answer change if the four models for K-values in Problem 12.14 are used? What do you learn from this comparison?

Problem 12.14

In the production of dimethyl carbonate from methanol, it is necessary to separate methanol from formal (also known as methylal—C₃H₈O₂). However, an azeotrope exists between these two components. Using a process simulator, examine the equilibrium curves (x-y plots) between 100 kPa and 1000 kPa to determine a strategy for purifying these two components. Compare your results for the following thermodynamic packages for the K-value:

1. Ideal

2. NRTL

3. UNIFAC

4. SRK

What do you learn from this comparison?