A strategy for predictive control of a mixed continuous batch process

This paper deals with the on-line control of mixed processes composed of continuous and batch units in which some continuous variables must be kept as close as possible at prescribed values and the batch units must be scheduled in order to avoid bottlenecks in production. In particular, a pilot plant is considered with product recycle involving simultaneous continuous and scheduling decisions. The problem is of hybrid nature and can be formulated as a hybrid predictive control model in terms of integer and continuous variables. However, as the system must be controlled in real-time, an alternative formulation is proposed based on a hierarchical view of the problem and the use of flow patterns and time of occurrence of events in the batch units. The paper describes the process, the control problem formulation, and provides results of some test in the pilot plant.