(652e) Scheduling for Dynamic Risk and Resource Management for Simultaneous Front-End Refinery Production and Maintenance

The front-end crude transport process (FCTP) is a critical sector of a refinery, which covers both discrete and continuous operations such as crude unloading, storage, pipeline transportation, blending, and feeding to crude distillation units. As the rapid development of the petroleum refinery in recent years, the optimality study of the FCTP system has become a hot topic. In reality, the FCTP system should also be concerned for its operating safety, robustness, and agility under different uncertainties. Thus, unit maintenance plans, which aims at recovering performance-decaying unit performances and prevent potential risks from escalating into catastrophic disasters, should be dynamically prescribed subject to risk management control and resource availability, as well as be seamlessly integrated with ordinary optimal manufacturing schedules. Unfortunately, such important studies are still lacking.

In this study, a new scheduling model for dynamic risk and resource management for simultaneous production and maintenance in the FCTP system has been developed. The developed model will optimize the crude movement in the FCTP system with the minimum operating cost; meanwhile, it can adaptively and timely adjust the unit maintenance plan for the FCTP system, which can minimize the dynamic system risk score with the satisfactory of available dynamic resource constraints. Furthermore, the model is general and can be iteratively employed with rolling time horizon techniques to accomplish dynamic scheduling mechanism internal or external uncertainties. The scheduling model can also handle multiple maintenance tasks at once with identifying the best time to isolate a unit for maintenance and the best time to resume its duty as well. The developed model has been demonstrated through a series of case studies to assure its efficacy.