Hydrogel-derived catalysts. Laboratory results on nickel-molybdenum and cobalt-molybdenum hydrotreating catalysts

Conventional nickel or cobalt modified molybdenum disulfide-containing hydrotreating catalysts are generally prepared by impregnation. While this route has proven to be quite successful and has led to a variety of commercial products, inherent in the pore volume impregnation technique are several potential limitations. These limitations may be chemical or economic in nature. In order to overcome these potential limitations, we have developed a new, one-step route to the oxidic form of these nickel or cobalt modified molybdenum disulfide-containing hydrotreating catalysts. This route consists of reacting the metals solutions directly with a precipitated alpha-alumina monohydrate (boehmite) hydrogel prior to extrusion. The metals-containing hydrogel is extruded directly to pellet form and subsequently dried and calcined. Catalysts formed appear to have benefits not seen with conventional catalysts. As an example, the metals efficiencies and utilization of these catalysts can exceed conventional catalysts by 25%. Volumetric performances of these catalysts can also be quite good. Surface areas of the new, gel-derived catalysts are significantly higher than conventional catalysts. Crush strengths of the gel catalyst pellets can show improved strength over conventionally-prepared catalysts. Possible reasons for the enhancements in properties are discussed as well as details of the experimental procedures required to prepare these catalysts.