Oil refineries use hydrogen for removing undesired impurities in fuels. As heavier crude oil is upgraded to meet the market demand of cleaner fuels, hydrogen consumption is rapidly growing. To meet more and more stringent environmental regulations as well as to reduce costs, it becomes imperative to minimize hydrogen consumption.

Optimizing the structure of the hydrogen network is an essential task to efficiently reduce the use of hydrogen in oil refineries. Indeed, the quantity consumed is determined by the degree of impurity removal in the different hydrotreating (HDT) units, which operate sequentially one after the other in the refinement process.

Artelys Knitro can be employed to solve the complex nonlinear models for hydrogen network optimization. Compared to the original operations, the optimization allows to achieve a reduction of the hydrogen consumption up to 44% and a total annual cost saving up to 34%. In addition, the environmental impact of the hydrogen network (evaluated according the Eco-indicator 99) is shown to decrease by up to 38%.