GB762111A - Improvements in or relating to process for refining hydrocarbon oils - Google Patents

Abstract

Hydrocarbon oils boiling within the range of about 300-650 DEG F and containing mercaptans and phenols, are refined by solvent extracting with liquid SO2 at a temperature below about 35 DEG F., and then treating the SO2-free raffinate with free oxygen at a temperature below about 120 DEG F., in the presence of a catalyst comprising cupric chloride, water and an inert carrier, to produce a substantially mercaptan-free oil. The hydrocarbon oils may be straight-run petroleum fraction or may be derived from the thermal or catalytic cracking, or the hydrodesulphurization, of a petroleum fraction; the oils may be kerosenes, heated oils, burning oils, furnace oils, diesel fuels or jet fuels. Examples of suitable inert carriers are Fullers' earth, silica gel, diatomaceous earth, pumice, charcoal, coke and alumina. Apparatus is described in which a virgin petroleum heater oil is de-aerated, for example by vacuum treatment, dehydrated, for example by contact with calcium chloride, rock salt, magnesium silicate or alumina gel or by vacuum distillation and extracted with liquid SO2 at 10 DEG F. The extract phase thus obtained contains phenols and aromatic hydrocarbons. The extract and raffinate phases are freed of SO2 and the latter is purified and returned for re-use. The raffinate is washed with aqueous caustic alkali to remove traces of SO2 and then freed from traces of caustic alkali solution, for example by contact with rock salt, excelsior, fibre glass or steel wool. Air or oxygen is injected into the SO2-free raffinate and a slurry is made with a portion of the raffinate and a catalyst made up of about 20 per cent cupric chloride about 12 per cent water and the remainder attapulgus clay. The main body of oxygenated raffinate is contacted with the catalyst slurry at 90 DEG F., freed of catalyst, water-washed and dehydrated by contact with rock salt. N, N1-disalicylidene-1, 2-diamino-propane may be added as metal deactivator to the refined oil thus obtained. For comparison purposes, the effect of deferring the extraction with liquid SO2 until after the treatment with oxygen in the presence of the cupric chloride-containing catalyst is described.