ABSTRACT
Hydrotreating is the catalytic addition of hydrogen over metal or sulfided metal catalysts. It is usually performed using a fixed bed reactor, with one or more catalyst beds. Hydrotreating is exothermic, and depending on the nature of the feed and extent of conversion, heat management can be very important. Many hydrotreating reactions are reversible and the hydrogenation–dehydrogenation equilibrium affects the conversion level that can be achieved. Catalytic hydrogenation is employed in different ways, both on its own, as well as in combination with other reactions. Most petroleum refineries have two or more hydrotreaters, because hydrotreating is used in so many different roles. Hydrotreating is applied to a wide range of feedstocks, from naphtha to reduced crude. For most feed materials the hydrotreating reactor is operated as a trickle bed reactor, with the oil feed in the liquid phase. Hydrodesulfurization is probably the most extensively studied of all of the hydrotreating reactions due to its importance in meeting transport fuel specifications.
