Online optimization implementation on model predictive control in chemical process

Multi-layer model predictive control has become the mainstream method in industrial process control. Based on this control structure, original steady-state optimization was embodied in two main situations according to different desired values obtained from the operator or upper process optimization. An optimization problem with a compound objective function was proposed to calculate the target for MPC, which could degenerate into linear or quadratic form or the combination of both due to diverse process requirements. In order to ensure that ultimate optimal target was feasible and critical variables were not saturated, adjustment measure was taken when it was infeasible. Aiming at ensuring the consistency of variables between optimization implementation and MPC, the optimal target was transformed into incremental form. Simulation results of the constrained CSTR system showed that the optimization implementation layer provided appropriate optimal target effectively for MPC towards various process requirements, which demonstrated feasibility of the proposed method. ©All Rights Reserved