Optimality for Batch Distillation Configurations

Abstract The paper examines a batch distillation column consisting of two separation sections with a vessel in between. The behavior of the column is analyzed using the infinite separation and the minimum reflux models. Using the minimum reflux model, the optimal control problem is solved when both products are pure throughout the separation process. It is shown that the minimum reflux/reboil ratio policy is optimal for the separation of an ideal mixture or any binary mixture, and that the optimal operation is at the steady state for a binary separation when there is no tangent pinch. Based on the optimal operation policy and the minimum reflux model, various batch configurations are compared with respect to separation time. Guidelines are provided which configuration is best for a given mixture.