Scheduling optimization of refinery operations based on production continuity

Production continuity is an important process characteristic which receives significant attentions in actual refinery process. However, there hasn't been a sufficient and comprehensive expression of production continuity in literatures of refinery scheduling. The core of this paper is to deal with the scheduling optimization problem of refinery operations based on production continuity. The quantitative performance evaluation criterion of production continuity is given, and the scheduling problem is formulated as a generalized disjunctive programming (GDP) model relied on discrete time representation. The model describes production continuity during different scheduling periods using disjunctive normal form and logic proposition as well as proposed heuristics, and optimizes refinery operations by maximizing production profit and continuity performance. The formulation approach is used to address the scheduling of a refinery. Case study shows that the optimal schedule obtained from the proposed model is more feasible and practical, which illustrates the model's efficiency.