Activity hydroprocessing units

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. 

The ex-situ presulfided catalysts having an oxysulfide form of active metals can be converted into a sulfided form during the activation stage in a hydroprocessing reactor, providing a quick and convenient start-up of the commercial units. 

Production planning is an important activity in modem refineries. The modem refinery is a combination of many complex units such catalytic reforming, fluid catalytic cracking (FCC), hydroprocessing, etc. While it is possible to tune each unit to an optimal yield, the optimum yield of a particular unit may not reflect a true optimum because of the demands and prices for the wide range of products that the refiner produces. Therefore, it is important to consider each unit in the context of the whole refinery. The activity of choosing feedstock to refinery (and... 

---