Operability analysis and nonlinear model predictive control of a styrene polymerization reactor

We show how bifurcation analysis is used to detect regions of infeasible steady-state operation in a jacketed, styrene polymerization reactor. The selected operating point is close to an infeasible region rendering single input-single output control of reactor temperature impossible, once model uncertainty is considered. We apply a multivariable nonlinear quadratic dynamic matrix control (NL-QDMC) strategy to this problem. The NL-QDMC algorithm incorporates an extended Kalman filter to handle state variable and parameter estimation; also included is an integrated white noise disturbance model. The initial case study is based on the use of coolant and monomer flow rates to regulate the reactor temperature, subject to noisy measurements, disturbances and varying process parameters. We also show results for the control of number average molecular weight and reactor temperature by manipulating coolant and initiator flow rates