Reaction hydroprocessing units

A pre-treated Maya residue has been hydrotreated catalytically in a continuous hydroprocessing unit provided with a perfectly mixed reactor. A commercial catalyst, Topsoe TK-751, has been used and kinetic study of hydrodemetallation reactions has been performed. 

In hydroprocessing units, cracking reactions - those that break carbon-to-carbon bonds - can be grouped into three main categories ... 

Figure 7.12 illustrates the recycle gas circuit throughout a hydroprocessing unit. First, the reaction product is sent to a HPS, where the liquid products are recovered from the gas mixture. Then the gas stream is sent to a scrubbing unit in order to remove hydrogen sulfide and ammonia by contacting with an amine. 

Transition metal sulfide units occur in minerals in nature and play an important role in the catalytic activity of enzymes such as hydrogenase and nitrogenase. Industrial processes use transition metal sulfides in hydroprocessing catalysis. Both the metal and the sulfur sites in these compounds can undergo redox reactions which are an important part of their reactivity. Thus, the electronic situation of the ReS4 anion and related complexes is of considerable interest and has been evaluated applying quantum chemical methods. 

Reactors, Catalyst Beds and Quench Zones. As shown in Table 4, most hydroprocessing reactions are exothermic. The heat released in naphtha and kerosene hydrotreaters is relatively low, so units designed for these feeds may use just one reactor that contains a single catalyst bed. However, for heavier feeds and/or feeds that contain large amounts of sulfur, aromatics or... 

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