A certain process in a chemical plant produces a low-pressure stream of 50 mol% acetone, 50 mol% water at 50 °C and 50 mmHg (absolute). You are tasked with removing most of the water so that the acetone can be used in another process elsewhere in the plant. The purified acetone stream must have a maximum of 10 mol% H2O, and your supervisor has asked that you achieve a minimum of 40% recovery of acetone. (Percent recovery is the percentage of all acetone fed to your process that ends up in the purified acetone product stream).
To achieve the desired separation, you design a 2-stage separation scheme. In the first stage, the feed is isothermally compressed to form a liquid phase that is 35 mol% acetone. The liquid is discarded, and the remaining vapor is isobarically cooled to 40 °C. This causes further condensation; the liquid phase is discarded, and the vapor phase is the purified acetone product.
Examine the efficacy of your process by doing the following:
(a) Determine the vapor pressures (in mmHg) of H20 and Acetone at the feed temperature and at the process outlet temperature.
(b) Determine the outlet pressure of the isothermal compression step (mmHg)
(c) Determine the composition of the purified product stream (mole fractions)
(d) Calculate the percentage recovery of the proposed process.
(e) Does this process meet the requested specifications for purity and recovery?