Nonlinear model predictive control of an industrial batch reactor subject to swelling constraint

This paper presents the application of nonlinear model predictive control (NMPC) to a simulated industrial batch reactor subject to safety and productivity constraints due to swelling. The catalyst used in the chemical process decomposes in the reactor; therefore it is fed in discrete time steps during the batch. Although the optimal reactor temperature profile, using a fixed catalyst dosing policy, is optimized off-line an on-line control solution is needed in order to accommodate the reaction rate and level disturbances which arise due to catalyst dosing uncertainty (feeding time and mass). The on-line control method is based on the shrinking horizon optimal control methodology and it uses a reaction and hydrodynamic model. It is concluded that the implemented shrinking horizon on-line optimization strategy is able to calculate the optimal temperature profile without causing level swelling.