Two-Point Temperature Control Structure and Algorithm Design for Binary Distillation Columns

Abstract

In this paper the problem of designing a two-point linear temperature controller for the regulation of the product compositions in binary distillation columns is addressed. The combination of feedforward, feedback, and internal model control concepts yields a control design methodology with (i) criteria to choose the (decentralized and one- or two-way) decoupling structure and the temperature measurements location, (ii) a linear control system that consists of a static interaction compensator and a pair of decoupled proportional−integral controllers with feed-temperature-based setpoint adjustment, (iii) an implementation that requires the static dependencies of the measured tray temperatures on the feed temperature, the slopes of the operating lines, and the temperature-gradient-to-holdup quotients in the measurement trays, and (iv) a conventional-like tuning scheme that resembles the ones employed in linear first-order controllers and filters. The linear controller recovers the behavior of a material-bal...