where is the warped time, is the initial still composition, and is the desired constant distillate composition.

VLE data is given by .

Finally, the reflux ratio is given by the following approximation:

.

This Demonstration plots the reflux ratio and the still composition as a function of warped time, . In addition, a parametric plot shows the behavior of the reflux ratio versus the still composition.

It is obvious that as the warped time increases, the still composition goes to zero (the light component in the still is depleted). Thus, in order to achieve constant distillate compositions, the reflux ratio has to be increased (up to excessively high values) and the cost of the batch distillation operation becomes very high.