HYDROCRACKING PROCESS

1429291 Hydrocracking; obtaining lubricating oil SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 5 March 1973 [7 March 1972] 10522/72 Heading C5E A lubricating oil is prepared from a mixture of heavy hydrocarbons which contains nitrogen and aromatics by adding a nitrogen compound and then hydrocracking in the presence of a catalyst comprising one or more metals from Group VIII or from the Cr and Mn sub-groups on a support of one or more oxides of elements of Groups II, III and IV, and fractionating the product. The feed may be a wax distillate, a slack wax, a deasphalted residual fraction of petroleum, or a solvent raffinate from such a residual fraction or from a heavy cracked oil. The nitrogen compound may be ammonia or an organic compound that is reduced to ammonia in the hydrocracking step (many listed). At least part of the nitrogen may be ammonia separated from the product and recycled. The catalyst may be that of Specification 1,390,359 or Specification 1,398,384 but others are also disclosed. The cracked product may be hydrofinished before fractionation. By adjusting the nitrogen content of the feed, one can obtain satisfactory yields of lubricating oil of a given VI from varied feeds without needing to change the catalyst. The product generally needs to be dewaxed.