Profile position control of batch distillation based on a nonlinear wave model

Abstract

Batch distillation poses challenging operation and control problems caused by a great change in process gain and a very nonlinear response in distillate composition during the operation. A nonlinear wave model captures an essential dynamic characteristic of the batch distillation column. A profile position control strategy based on the nonlinear wave model is proposed for the control of batch distillation columns. The profile position and distillate composition are estimated from selected tray temperature measurements by observers, which are based on the combination of the nonlinear wave propagation model and the quasi-dynamic model by Quintero-Marmol and Luyben (Chem. Eng. Sci. 1992, 47, 887). This control strategy has been applied to binary and multicomponent separation of ideal and nonideal mixtures. The proposed control scheme is shown to deal with severe nonlinear and varying process gains of batch operation and to be robust to model-plant mismatches.