Composition control in batch distillation: Binary and multicomponent mixtures

A strategy is proposed for the control of constant-distillate-composition o perations of batch distillation columns. The proposed control law is derive d in the framework of Nonlinear Internal Model Control. The distillate comp osition is estimated from selected tray temperature measurements by an obse rver. The same observer provides the estimate of the system states that are necessary for the computation of the control algorithm. Results are provid ed for binary and multicomponent separations of ideal and nonideal systems. Several sources of process/model mismatch are considered in order to provi de a realistic test scenario for,the proposed procedure. It is shown that t he proposed controller ensures fast and smooth transition from the startup phase to the production phase, and tight composition control until the end of the operation. Moreover, the tuning of the controller is performed very easily. Finally, the on-line computation of the control law is straightforw ard, which is a promising result toward practical implementation of the pro posed method.