On‐line multivariable adaptive control of a binary distillation column

Abstract

Abstract An experimental evaluation of the simultaneous control of top and bottom product compositions of a binary distillation column utilizing multi‐variable self‐tuning control algorithms is presented. The study was carried out using an 8‐tray, 22.86 cm diameter methanol–water pilot scale column with continuous capacitance analysis of top product composition and bottom composition analyzed on a 3 minute cycle, by a gas chromatograph. Column control is studied for ±25% step disturbances in feed flow rate. Terminal composition regulation using both ‘positional’ and ‘incremental’ forms of a generalized minimum variance self‐tuning control algorithm is compared with that achieved using a conventional digital PI/PID multiloop control strategy.