(51c) Optimization of Refinery Front-End Crude Process Production and Maintenance Schedule with Consideration of Risk and Resource Management

Studies on front-end crude transfer process (FCTP) scheduling problem of refinery have been highly attractive as a result of the rapidly developing petrochemical industry. FCTP scheduling is widely used to handle crude movement problems from crude imported by transportation vessels via berths, temporarily stored in the storage tanks (STs), transfer to the refinery through the long-distance pipeline (LDPL), blending in the charging tanks (CTs) on the refinery side, to continuous feeding to the crude distillation units (CDUs) for refining. Besides tackling various uncertainties in production and merchandising^1-3, the performance of one equipment will always decay with the process running. Consequently, maintenance activities have to be integrated with the production schedule to recover efficiency and to ensure the whole process runs normally^4,5. However, few works have considered the unexpected situation that may postpone the maintenance and the corresponding risk. Therefore, a well-scheduled production and maintenance plan should consider both the risk of delaying the maintenance job and resource availability at the time of conducting maintenance.

In this study, a new model for simultaneous production and maintenance scheduling of the FCTP systems has been developed. The proposed model covers the crude movement from vessel to the refinery processing, as well as the maintenance activities under the constrain of resource accessibility and risk-based management. the model can also handle multiple maintenance tasks at once with optimal deciding the best opportunity to isolate a unit for maintenance and resume its service after the maintenance. Real process regulations and requirements for crude storage, blending and movements, unit maintenance, and resource limitations are taken into consideration to assure the validity of the schedule in reality. The developed model has been tested over a set of case studies to verify efficacy and performance.

References:

[1] Zhang, S., Xu, Q., 2015. Refinery continuous-time crude scheduling with consideration of long-distance pipeline transportation. Comput. Chem. Eng. 75, 74–94.

[2] Xu, J., Qu, H., Wang, S., Xu, Q., 2017. A New Proactive Scheduling Methodology for Front-End Crude Oil and Refinery Operations under Uncertainty of Shipping Delay. Ind. Eng. Chem. Res. 56, 8041–8053.

[3] Assis, L.S., Camponogara, E., Menezes, B.C., Grossmann, I.E., 2019. An MINLP formulation for integrating the operational management of crude oil supply. Comput. Chem. Eng. 123,110-125.

[4] Qu, H., Wang, S., Xu, Q., 2019. Integrated Proactive and Reactive Scheduling for Refinery Front-End Crude Movement with Consideration of Unit Maintenance. Ind. Eng. Chem. Res. 58, 12192–12206.

[5] Panda, D., Ramteke, M., 2020. Dynamic hybrid scheduling of crude oil using structure adapted genetic algorithm for uncertainty of tank unavailability. Chem. Eng. Res. Des. 159, 78–91.