MULTIVARIABLE INTEGRAL CONTROLS FOR FIXED-BED REACTORS

A multivariable control system that regulates reactor product concentration to the set point is developed and tested on a laboratory reactor in which an exothermic reaction occurs. The system comprises a product concentration estimator and a multivariable proportional-integral controller that adjusts the flow rate and temperature of an injected quench stream. Estimator and control calculations are made by an on-line digital computer. The control system is shown by experiment to achieve excellent regulation of unmeasured concentration upon sustained step-like disturbances in feed concentration of 20 %. Hot-spot temperature is also controlled. The control system has the added feature of returning one of the manipulated inputs (the quench flow rate) to its nominal value so that the full range of this input is available to combat repeated step-like disturbances. © 1979, American Chemical Society. All rights reserved.