Optimal Scheduling of Pipeline Systems with a Resource-Task Network Continuous-Time Formulation

This work addresses the short-term scheduling problem involved in the pipeline transportation of refined petroleum products to distribution centers serving local markets. A new continuous-time formulation is proposed that can handle complex treelike systems involving multiple refineries and depots. The novelty concerns the modeling of the complex storage policy associated with the flow of multiple products inside the pipeline. This is accomplished through the use of real and accumulated volume resources for every product, coupled with filling, moving, and emptying tasks, under the scope of the resource-task network process representation. Computational studies are performed to compare the performance of the new approach to three models from the literature that rely on the concept of batches rather than events to model what is in reality a continuous system. The results show that the proposed approach is wider in scope with the typical drawback of being less efficient for structural subclasses of the general problem.