Hierarchically coordinated economic MPC plantwide control of mixed continuous-batch units in process industries with application to a beet sugar plant

Abstract

This paper deals with the optimal operation of processes that combine batch and continuous units. The proposed approach is based on a hierarchical architecture with two layers. The lower layer manages the optimal operation of the batch units in a noncentralized fashion, whereas the upper layer is concerned with the scheduling of the batch units and with their smooth integration with the continuous ones. The strategy has been applied to a challenging problem found at the interface of the fed-batch crystallizers with the upstream evaporation section in beet sugar factories. The presented approach aims at designing a system that can effectively perform the plantwide economic optimization, specifically addressing the issue of energy efficiency, while complying with all process and operational constraints.