Short-term scheduling of a large-scale oil-refinery operations: Incorporating logistics details



Refineries are increasingly concerned with improving the scheduling of their operations to achieve better economic performances by minimizing quality, quantity, and logistics give away. In this article, we present a comprehensive integrated optimization model based on continuous-time formulation for the scheduling problem of production units and end-product blending problem. The model incorporates quantity, quality, and logistics decisions related to real-life refinery operations. These involve minimum run-length requirements, fill-draw-delay, one-flow out of blender, sequence-dependent switchovers, maximum heel quantity, and downgrading of better quality product to lower quality. The logistics giveaways in our work are associated with obtaining a feasible solution while minimizing violations of sequence-dependent switchovers and maximum heel quantity restrictions. A set of valid inequalities are proposed that improves the computational performance of the model significantly. The formulation is used to address realistic case studies where feasible solutions are obtained in reasonable computational time. © 2010 American Institute of Chemical Engineers AIChE J, 2011