Logistics optimization for dispositions and depooling of distillates in oil-refineries: closing the production scheduling and distribution gap

At the edge of the manufacturing of crude-oil distillates into refined final products, the production scheduling and distribution gap can be reduced by optimizing production rundown switches of dispositions of distillates in a mixed-integer linear model (MILP) considering discrete time-steps of days, shifts or hours for a delivery horizon of weeks or months. From the process network down to the product distribution side, there are definitions on the assignments and amounts of distillates to be dispatched downstream for further process- and blend-shops considering diverse tank farms and nodes for the distribution. However, such integration of the refining process and tank storage systems can become intractable for industrial-sized problems with complex scheduling configurations considering time-varying rundown supply rates, product demands and pricing. For this, we propose to model the dispositions of distillates using unit-operations as modes of transportation from the distillation sources to the tanks of process-shops and blend-shops for downstream processing and blending before the primary distribution. Additionally, by solving with pooling (groups of tanks) first then post-solve to depool by disaggregating the pooled solution, the determination of the distillate dispositions to tank assignments is facilitated given that scaling to industrial-sized cases without tank aggregation is complicated as highlighted in the examples. Better prediction of the operations scheduling by using small discrete time-steps within a planning horizon allows opportunities for exploring the contract and spot market plays of the finished products.