1. Introduction Process engineering deals with, among others, production and operations optimization. The operational level is not only an important contribution to improve profit margins, but also a decisive level for process efficiency and efficacy. One of the activities included in the operational level is inventory management. A poor inventory management can shut down a factory for several days or run poorly a supply chain. On the other hand, if there is an optimal inventory management at the operational level, it is possible to improve the profit of a company as well its efficiency. The major part of the existing literature focuses on inventory management of end products from manufacturing industries. This is related with end products, where discrete quantities are managed. Nevertheless, other inventory types are more common in the process industry, such as petroleum, petroleum derivatives or petrochemical products, which are managed in bulk liquid quantities. These products are usually stored in tanks located in tank farms where upstream and downstream operations contribute to their inventory management. The petroleum supply chain (PSC) involves many entities at different locations which perform different processes and tasks. Besides improving the refining process, which is the core activity, the supply chain requires high level logistics management so as to reduce costs and fulfil the market properly. Therefore, inventory management is