When a nickel on silica-alumina catalyst is sulfided, two of the principal changes observed in the hydrocracking of n-decane are: (1) the over-all rate of reaction increases greatly and (2) the predominant reaction changes from isomerization to cracking. This type of cracking is similar to that observed with the silica-alumina support alone. It is concluded from these and other observations that the catalyst before sulfiding contains both nickel metal and nickel salts of the silica-alumina acid sites. On sulfiding, the nickel metal is converted to nickel sulfide, and the HzS reacts with the nickel-silica-alumina salts to regenerate the original strong acid sites of the silica-alumina support.
Paraho shale oil is too high in nitrogen (2.2%) and other contaminants to be used directly as a fuel in most current applications. The key to successful shale oil refining is a hydrotreating process to remove these contaminants. In this study, nitrogen was reduced to concentrations as low as 1 ppm in the hydrotreated whole oil in a single catalytic stage using a catalyst containing nickel, tungsten, silica, and alumina. However, it is economically preferable to hydrotreat at less severe conditions to convert the shale oil to a premium synthetic crude containing about 500 ppm of nitrogen. This synthetic crude resembles a typical hydrorefined petroleum gas oil and is suitable for downstream processing to specification transportation fuels in conventional modern refineries.fois chapter presents results of a Chevron Research Company study sponsored by the U.S. Department of Energy (DOE) to demonstrate the feasibility of converting whole shale oil to a synthetic crude resembling a typical petroleum distillate. The synthetic crude thus produced then can be processed, in conventional petroleum-refining facilities, to transportation fuels such as high-octane gasoline and diesel and jet fuels. The raw shale oil feed used in this study is a typical Colorado shale oil produced in a surface retort in the so-called indirectly heated mode.Crude shale oil is an important potential source of transportation fuels when properly refined. However, although it is low in sulfur compared with mid-East crudes, it is much higher in nitrogen than typical petroleum crudes. The shale oil used in this study contains 2.2 wt % nitrogen; typical petroleum crudes contain less than 0.3% nitrogen. 0-8412-0456-X/79/33-179-025$06.75/l
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