Cobalt-molybdenum hydrotreating

X-Ray Absorption Fine Structure, Mossbauer, and Reactivity Studies of Unsupported Cobalt-Molybdenum Hydrotreating Catalysts... 

Ferroflning A mild hydrotreating process for purifying lubricating oils. The catalyst contained cobalt, molybdenum, and iron (hence the name). Developed by the British Petroleum Company and first operated in Dunkirk, England in 1961. 

We begin with the structure of a noble metal catalyst. The emphasis is on the preparation of rhodium on aluminum oxide and the nature of the metal-support interaction. Next we focus on a promoted surface in a review of potassium on noble metals. This section illustrates how single crystal techniques have been applied to investigate to what extent promoters perturb the surface of a catalyst. The third study deals with the sulfidic cobalt-molybdenum catalysts used in hydrotreating reactions. Here we are concerned with the composition and structure of the catalytically active... 

Hydrotreating also produces some residuals in the form of spent catalyst fines, usually consisting of aluminum silicate and some metals (e.g., cobalt, molybdenum, nickel, tungsten). Spent hydrotreating catalyst is now listed as a hazardous waste (K171) (except for most support material). Hazardous constituents of this waste include benzene and arsenia (arsenic oxide, AS2O3). The support material for these catalysts is usually an inert ceramic (e.g., alumina, AI2O3). 

Hydrotreating Refining process to remove sulfur, nitrogen, and oxygen from petroleum feedstocks by contacting with hydrogen in the presence of a nickel/molyb-denum or cobalt/molybdenum on alumina catalyst. 

Authentic and synthetic solvent-refined coal filtrates were processed upflow in hydrogen over three different commercially available catalysts. Residual (>850°F bp) solvent-refined coal versions up to 46 wt % were observed under typical hydrotreating conditions on authentic filtrate over a cobalt-molybdenum (Co-Mo) catalyst. A synthetic filtrate comprised of creosote oil containing 52 wt % Tacoma solvent-refined coals was used for evaluating nickel-molybdenum and nickel-tungsten catalysts. Nickel-molybdenum on alumina catalyst converted more 850°F- - solvent-refined coals, consumed less hydrogen, and produced a better product distribution than nickel-tungsten on silica alumina. Net solvent make was observed from both catalysts on synthetic filtrate whereas a solvent loss was observed when authentic filtrate was hydroprocessed. Products were characterized by a number of analytical methods. 

Hydrotreating is carried out by charging the feed to the reactor together with a portion or all of the hydrogen produced in the catal3ffic reformer, djlatalysts suitable are tungsten-nickel sulfide, cobalt-molybdenum-alumina,... 

The catalysts developed for hydrotreating include cobalt, molybdenum, nickel, vanadium and tungsten oxides on alumina. Cobalt and molybdenum oxides on alumina catalysts are in greater use today, being highly selective, easy to regenerate and relatively resistant to poisons. 

Catalyst choice is strongly influenced by the nature of the feedstock to be hydrotreated. Thus, whereas nickel-promoted and cobalt—nickel-promoted molybdenum catalysts can be used for desulfurization of certain feedstocks and operating conditions, a cobalt-promoted molybdenum catalyst is generally preferred in this appHcation. For denitrogenation and aromatics saturation, nickel-promoted molybdenum catalysts usually are the better choice. When both desulfurization and denitrogenation of a feedstock are required, the choice of catalyst usually is made so that the more difficult operation is achieved satisfactorily. 

Cobalt in Catalysis. Over 40% of the cobalt in nonmetaUic appHcations is used in catalysis. About 80% of those catalysts are employed in three areas (/) hydrotreating/desulfurization in combination with molybdenum for the oil and gas industry (see Sulfurremoval and recovery) (2) homogeneous catalysts used in the production of terphthaUc acid or dimethylterphthalate (see Phthalic acid and otherbenzene polycarboxylic acids) and (i) the high pressure oxo process for the production of aldehydes (qv) and alcohols (see Alcohols, higher aliphatic Alcohols, polyhydric). There are also several smaller scale uses of cobalt as oxidation and polymerization catalysts (44—46). 

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