Residue Curves for Different Activity Coefficient Models

This Demonstration plots the residue curve passing through a location chosen by the user for a ternary mixture of chloroform, acetone, and methanol at 1 atm.

This mixture presents liquid-phase deviation from ideal behavior, which is taken into consideration by using activity coefficients as predicted by one of the following three models: Wilson, NRTL (non-random two-liquids), and UNIQUAC (UNIversal QUAsi-Chemical).

Residue curve map computation is essential in understanding the distillation behavior of ternary mixtures. Such a calculation also allows the determination of binary and ternary azeotropes, which appear naturally as saddle points, stable nodes, and unstable nodes.