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Jorge Ancheyta , James G. In fact, the vast majority of the 64,, metric tons of sulfur produced worldwide in was byproduct sulfur from refineries and other hydrocarbon processing plants. An HDS unit in the petroleum refining industry is also often referred to as a hydrotreater. Although some reactions involving catalytic hydrogenation of organic substances were already known, the property of finely divided nickel to catalyze the fixation of hydrogen on hydrocarbon ethylene , benzene double bonds was discovered by the French chemist Paul Sabatier in Soon after Sabatier's work, a German chemist, Wilhelm Normann , found that catalytic hydrogenation could be used to convert unsaturated fatty acids or glycerides in the liquid phase into saturated ones.
He was awarded a patent in Germany in  and in Britain in ,  which was the beginning of what is now a worldwide industry.
Hydroprocessing of Heavy Oils and Residua (Chemical Industries)
In the mids, the first noble metal catalytic reforming process the Platformer process was commercialized. At the same time, the catalytic hydrodesulfurization of the naphtha feed to such reformers was also commercialized. In the decades that followed, various proprietary catalytic hydrodesulfurization processes, such as the one depicted in the flow diagram below, have been commercialized.
Currently, virtually all of the petroleum refineries worldwide have one or more HDS units. By , miniature microfluidic HDS units had been implemented for treating JP-8 jet fuel to produce clean feed stock for a fuel cell hydrogen reformer. Hydrogenation is a class of chemical reactions in which the net result is the addition of hydrogen H.
Hydroprocessing of Heavy Oils and Residua | Taylor & Francis Group
Hydrogenolysis is a type of hydrogenation and results in the cleavage of the C-X chemical bond , where C is a carbon atom and X is a sulfur S , nitrogen N or oxygen O atom. The net result of a hydrogenolysis reaction is the formation of C-H and H-X chemical bonds. Thus, hydrodesulfurization is a hydrogenolysis reaction. Using ethanethiol C 2 H 5 SH , a sulfur compound present in some petroleum products, as an example, the hydrodesulfurization reaction can be simply expressed as. For the mechanistic aspects of, and the catalysts used in this reaction see the section catalysts and mechanisms.
Occasionally, a combination of nickel and molybdenum called NiMo is used, in addition to the CoMo catalyst, for specific difficult-to-treat feed stocks, such as those containing a high level of chemically bound nitrogen. The image below is a schematic depiction of the equipment and the process flow streams in a typical refinery HDS unit. The liquid feed at the bottom left in the diagram is pumped up to the required elevated pressure and is joined by a stream of hydrogen-rich recycle gas. The resulting liquid-gas mixture is preheated by flowing through a heat exchanger.
Hydroprocessing of Heavy Oils and Residu
The preheated feed then flows through a fired heater where the feed mixture is totally vaporized and heated to the required elevated temperature before entering the reactor and flowing through a fixed-bed of catalyst where the hydrodesulfurization reaction takes place. The hot reaction products are partially cooled by flowing through the heat exchanger where the reactor feed was preheated and then flows through a water-cooled heat exchanger before it flows through the pressure controller PC and undergoes a pressure reduction down to about 3 to 5 atmospheres.
Most of the hydrogen-rich gas from the gas separator vessel is recycle gas, which is routed through an amine contactor for removal of the reaction product H 2 S that it contains. The H 2 S -free hydrogen-rich gas is then recycled back for reuse in the reactor section. Any excess gas from the gas separator vessel joins the sour gas from the stripping of the reaction product liquid.
The liquid from the gas separator vessel is routed through a reboiled stripper distillation tower. The bottoms product from the stripper is the final desulfurized liquid product from hydrodesulfurization unit.
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Many oil refineries employ hydroprocessing for removing sulfur and other impurities from petroleum feedstocks. Capable of handling heavier feedstocks than other refining techniques, hydroprocessing enables refineries to produce higher quality products from unconventional - and formerly wasted - sources.
Hydroprocessing of Heavy Oils and Residua illustrates how to obtain maximum yields of high-value products from heavy oils and residue using hydroprocessing technologies. While most resources on hydroprocessing concentrate ongas oil and lower boiling products, this book details the chemistry involved and the process modifications required for the hydroprocessing of heavy crude oils and residua.
Emphasizing the use of effective catalysts to ensure cleaner and more efficient industrial fuel processes, the book presents key principles of heterogeneous catalyst preparation, catalyst loading, and reactor systems. It explains how to evaluate and account for catalysts, reactor type, process variables, feedstock type, and feedstock composition in the design of hydroprocessing operations.