Design of integrated real-time optimization and model predictive control for distillation column

This paper presents two integration approaches of real time optimization (RTO) and model predictive control (MPC) with the application to a distillation column. In particular, we present the modified RTO/MPC integration in the 2-layer structure and 3-layer structure. The 2-layer structure is constructed based on the conventional hierarchical control layer. In the 3-layer structure, the quadratic programming (QP) layer is inserted to compute the feasible set points for the MPC layer. Then, we apply the design methods to the distillation column. The simulation results illustrate the differences in the transient responses of two integration structures. The stability test shows that the 3-layer structure gives better results than that of the 2-layer structure in enforcing the stability of the system.