Optimal temperature control in a batch polymerization reactor using nonlinear generalized predictive control

摘要

The application of Non-Linear Generalized predictive Control (NLGPC) to the free radical solution polymerization of styrene in a jacketed batch reactor has been realized.The dynamic behavior of polymerziation reactor is modelled and simulated for control purposes.The optimal temperature policies for mininmum time,desired conversion and molecular chain length were obtained at different initiator concentrations by applying the optimal control theory which is based on the Hamiltonian principle.The polynomial Nonlinear auto Regressive Integrated Moving Average with eXternal input (NARIMAX) model is used to relate the reactor temperature with heat input for nonlinear control algorithm.The linear (ARIMAX) and nonlinear (NARIMAX) models are utilized in the GPC algorithm for comparison.A Pseudo Random Binary Sequence (PRBS) signal was employed tooperate the system.The model paraters are evaluated by using Levenberg Marquart Method.The NLGPC,Linear Generalized Predictive Control (LGPC) and standard PID controllers are applied experimentally to the polymerziation reactor by using on-line computer control system.The performance of NLGPC control system was compared with LGPC and standard PID controller.It is concludied that the NLGPC control gives much better performance than the other.