An Overview of Hydrodesulfurization and Hydrodenitrogenation

Abstract

Hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) of petroleum products and intermediates are reviewed to provide the basis for developing processes to produce gasoline and diesel oil with very low sulfur content. The reactivity, selectivity and inhibition (susceptibility of substrate molecules to inhibitors) in the catalytic process are very important to develop efficient processes. Recent advances in the understanding of active species, supports and supporting methods are also critically reviewed to suggest the design of catalysts with adequate activity to satisfy future regulations on transportation fuels. Details of the structures of the catalysts are not discussed, but the mechanisms of hydrodesulfurization and inhibition are summarized. Catalyst deactivation and reactor design are also briefly reviewed. New approaches to achieve deep hydrodesulfurization are proposed.

Effect of Polyethylene Glycol Addition on NiO-MoO₃/Al₂O₃ and NiO-MoO₃-P₂O₅/Al₂O₃ Hydrodesulfurization Catalyst

“…The reason for the selective improvement of HDS activity is not clear yet. However, one explanation is that the HDS reaction proceeds through the direct HDS route, which is not related to hydrogenation 10) . On the other hand, HDN and HDM reactions mainly occur after aromatic saturation and the active site of hydrogenation reaction is different from that of the HDS reaction 11) 13) .…”

Effects of Support on Formation of Active Sites and Hydrodesulfurization Activity of Rhodium Phosphide Catalyst

“…However, the effect of the support on the HDS activity of Rh2P catalyst remains unknown. The support affects the HDS activity of CoMo catalyst 31) and the acidity of the support enhances the sulfur tolerance of noble metalbased HDS catalyst 32)～34) . Since AlPO4 inhibits formation of Ni2P, Al2O3 is not suitable as a support for Ni2P catalyst 22) .…”

Desulfurization of Heavy Oil with Iron Oxide-based Catalysts Using Steam

“…Cyclic sulfur compounds including DBT are less reactive than acyclic sulfur compounds 1) . However, DBT was decomposed using the present catalyst in a steam atmosphere.…”

“…Heavy oil contains various types of sulfur compound. The structure of the sulfur compounds affects the ease of sulfur removal 1) . Acyclic sulfur compounds including thiols and disulfides can be easily removed.…”