Abstract
For short-term scheduling of crude oil operations in refinery, often crude oil residency time constraint and charging-tank-switch-overlap constraint are ignored by mathematical programming models to make the problem solvable. Thus, a schedule obtained by such mathematical programming models is infeasible and cannot be deployed. To solve this problem, this work studies the short-term scheduling problem of crude oil operations in a control theory perspective. The system is modeled by a hybrid Petri net and a short-term schedule is seen as a series of control commands. With this model, schedulability analysis is carried out and schedulability conditions are presented. These conditions can be used as constraints for finding a realizable and optimal refining schedule. Moreover, based on the proposed approach, a detailed schedule can be easily obtained given a realizable refining schedule. In this way, the complexity for the short-term scheduling problem of crude oil operations in refinery is greatly reduced and effective techniques and tools for practical applications can be obtained.
Note to Practitioners-Because of the complexity of short-term scheduling for oil refinery processes, it lacks effective techniques and software tools for practical applications. This paper presents a unique methodology for the short-term scheduling problem of crude oil operations. By studying this problem in a control theory perspective, schedulability conditions are developed by considering all constraints, some of which are ignored by a mathematical programming method. With the schedulability conditions, a detailed short-term schedule can be easily found. Thus, it can be applied to solve industrial-size problems.