(8l) Integrated Scheduling of Refinery Production and Pipeline-based Multi-oil Product Distribution

Refinery production and product distribution systems are two critical sectors and highly correlated in the entire refinery supply chain. If they were simultaneously scheduled in an integrated way, it could not only increase the industrial profitability, but also reduce the management risks for both sectors. For instances, based on stable supplies of oil products from refineries, inventories of distribution center could be kept in reasonable lower levels to reduce the inventory cost; meanwhile, based on a reliable demand from distribution center, the refinery plant could avoid unnecessary overproductions. Therefore, refinery production and product distribution should and could be optimally integrated if at any possibility. Certainly, such simultaneous scheduling work presents a big challenge.

Existing publications either focused on the strategic and tactical decision level for the upstream and midstream, or, sequentially or simply considered the scheduling problem with a discrete framework. However, there is still a lack of the systematic and integrated study dealing with a detailed continuous-time and continuous-slot scheduling with long-distance pipeline system. In this study, a continuous-time based integrated MINLP model is developed to optimize the scheduling of both refinery manufacturing operation and multi-oil product distribution. The general objective is to maximize the total profit; meanwhile, operation and product specifications, inventory limits, transportation constraints and production demands should be satisfied. The scope of this modeling work includes two main parts: refinery and long-distance pipeline distribution parts. The refinery part includes crude distillation, reforming, cracking, hydrotreating, blending, gas processing, and sulfur recovering facilities. The long-distance pipeline distribution part connecting the refinery plant and multiple depots, which send out multi-oil product to local consumer markets. Each depot contains various oil-product storage tanks and mixing tanks dedicated to hold pure products and mixtures respectively. Important operating features such as feed and product blending, multiple depots receiving oil product simultaneously, brine settling time, and interface mixing between two kinds of products inside pipeline have been fully modelled or constrained. The efficacy of the developed integrated scheduling model is demonstrated by a detailed case study.