Simple Trial-and-Error Algorithm to Determine Distillation Boundaries

Consider a ternary mixture of chloroform, acetone, and benzene at 1 atm. There is only one azeotrope (labeled in the ternary diagram). This binary azeotrope ( mole % chloroform and mole % acetone) is a saddle point; benzene is a stable node while both chloroform and acetone are unstable nodes. The distillation lines can be easily plotted for various values of the parameter (see Details). There are two distillation regions for this particular mixture, which are separated by a distillation boundary. This Demonstration shows how one can use trial and error to determine an approximate location of this boundary by varying . Indeed, the length of a distillation line reaches a maximum when corresponds to the distillation boundary. Values of the lengths of the trajectories are given in the ternary plot. A good choice for this case is .