Analysis and nonlinear model predictive control of the Chylla-Haase benchmark problem

A model based control solution is given for an industrial benchmark problem concerning temperature control of a semibatch polymerization reactor. The original model given by Chylla and Haase (1993) is critically analyzed. The simulation study carried out with a modified benchmark model treats a realistic industrial scenario where process knowledge is incomplete. Reaction kinetics and heat transfer coefficient are assumed to be unknown and measurement information is limited. The proposed control strategy is based on nonlinear model predictive control in combination with an extended Kalman filter. The process model used in both the controller and filter comprises a calorimetric reactor model and a nonlinear model of the cooling system. The control strategy is shown to be robust against parametric uncertainties and batch to batch variations. It is compared to PID control with and without compensation of the estimated heat of reaction.