STUDY OF ADAPTIVE INFERENTIAL CONTROL FOR A DISTILLATION COLUMN

Abstract

Distillation processes are difficult to control because product compositions cannot be measured on-line rapidly and economically. Due to this fact inferential control has been studied, that uses secondary measurements, such as temperature etc. to infer compositions. Success of inferential control scheme depends heavily on the availability of a good estimator. Adaptive control strategy can be applied to the inferential control system for giving more robust control. In recent years industrial interest in batch distillation has increased significantly. Many articles dealing with batch distillation have appeared in the literature, but little attention has been paid to he problems of control. The objective of the present work was to design an estimator for batch distillation system for inferential control and study the performance of estimator. Steady state model of estimator was studied computation technique and computer program was developed for estimator. Response of estimator for several inputs was studied. It was observed that the steady state model for estimator was good enough to predict reasonably accurate value of top product composition of all the components using measured values of top and bottom tray temperature. The response of estimator was foundsatisfactory and being a critical component, of the inferential control closed-loop system of a batch distillation column this estimator may be used for the design of the control system.