The method was first published by Warren L. McCabe and Ernest Thiele in 1925, and is a graphical procedure of determining the number of trays within a distillation collumn. The Murphree tray efficiency modifies the equilibrium curve of the two components in order to better account for non-idealities.

The current implementation presented here allows for a Murphree efficiency to be applied to the classical McCabe-Thiele plot. Whilst it is relatively easy online to find McCabe-Thiele 'calculators', there are few that have implementations accounting for the Murphree plate efficiency.

• The molar heats of vaporization of the feed components are equal
• For every mole of liquid vaporized, a mole of vapor is condensed
• Heat effects such as heats of solution are negligible

We have already developed the McCabe-Thiele Graphical Method for cascades. The sameequations we used for the operating lines, q-line, and equilibrium curve can be used to solve for the compositions in each stage algebraically.