Transition Metal Sulfide Catalysts for Petroleum Upgrading – Hydrodesulfurization Reactions

Abstract

Environmental catalysis researchers worldwide have focused much attention on the development of catalytic systems capable of reducing the sulfur amount present in petroleum feedstocks until levels globally established by the recently enacted environmental protection laws. In this regard, the maximum sulfur content present in diesel fuel to obtain an Ultra Low Sulfur Diesel (ULSD) is of 10 ppm in the European Union from the beginning of 2009 with the entry into force of the Euro V fuel standard directive. Meanwhile this limit is slightly higher in the United States, 15 ppm, regulated by the Environmental Protection Agency (EPA) (Hsu & Robinson, 2006). Thus, the development of highly active and selective HDS catalysts, capable of processing these feeds, is one of the most important problems that the petroleum industry has to face nowadays.