A novel modelling approach to scheduling of multipurpose batch processes

Abstract A great number of mathematical models have been developed for scheduling of multipurpose batch processes in the last three decades. None of them allow consumption and production tasks related to the same states to take place at the same event. It also seems that most unit-specific event-based models are task-specific instead. In this work, we introduce a new definition of recycling tasks and develop two novel mathematical models using unit-specific and task-specific event-based approaches. Both models allow consumption tasks to take place at the same event points with their related production tasks that are not recycling tasks. The computational results indicate that both models solve all examples to optimality using significantly less number of event points. Furthermore, it seems that the proposed unit-specific event-based model obtains optimal solutions in up to one magnitude less computational time compared to the proposed task-specific event-based model and the model of Shaik and Floudas (2009).