Chapter 7, Problem 7.46P

A mixture containing 65.0 mole% acetone (Ac) and the balance acetic acid (AA) is separated in a continuous distillation column at 1 atm. A ?owchart for the operation is as follows:

The stream from the top of the column is a vapor that passes though a condenser. The condensed liquid is divided into two equal streams: one is taken off as the overhead product (distillate) and the other (the re?ux) is returned to the column. The stream from the bottom of the column is a liquid that is partially vaporized in a reboiler. The liquid stream emerging from the reboiler is taken off as the bottoms product, and the vapor is returned to the column as boilup. Negligible heat is lost from the column, so that the only places in the system where external heat transfer takes place are the condenser and the reboiler.

Thermodynamic Data
$\hat{H}\left(\text{cal/mol}\right)$
Acetone			Acetic Acid
T(°C)	${\hat{H}}_1$	${\hat{H}}_{\text{v}}$	${\hat{H}}_1$	${\hat{H}}_{\text{v}}$
56.8	0	7205	0	5723
63.0	205	7322	194	6807
67.5	354	7403	335	6884
98.7	1385	7946	1312	7420

1. Taking 100 mol of feed as a basis, calculate the net heat requirement (cal) for the process. (You may neglect heats of mixing, although doing so for dissimilar liquids like acetone and acetic acid may introduce some error.)
2. For the same basis, calculate the required heat input to the reboiler and the required heat removal from the condenser.

Suppose that instead of the condensed liquid from the top of column being split into two equal streams to form the re?ux and the overhead product, it is split into two streams, with the re?ux being 3 times the overhead product. As before, take a basis of 100 mol of feed and determine the net heating requirements (cal) for the process and the heat removed in the condenser and added in the reboiler.