GB477663A - Improvements relating to the refining of lubricating oils - Google Patents

Abstract

<PICT:0477663/III/1> Hydrocarbon lubricating oils are refined, to improve their viscosity index, by blowing with air at a temperature between 350 DEG F. and 500 DEG F. until reaction ceases, and then treated with sulphuric acid or with a solvent having a selectivity for cyclic compounds of low viscosity index. The hydrocarbon oil may be a dewaxed or undewaxed distillate or residium of the lubricating oil range. The oxidation treatment usually takes from two to eight hours, about 1000 c.ft. of air being used for 42 gallons of oil. Specified selective solvents which may be employed are liquid sulphur dioxide, phenol, cresols, esters of phosphoric acid, aniline, furfurol, nitrobenzene and b .b <1>-dichlordiethyl ether. The treated oil may be subjected finally to a clay contact or clay percolation treatment at a temperature of at least 300 DEG F. In an example, a dewaxed raw distillate is blown with air for 4\ba1/2\be hours at 400 DEG F., cooled, treated with 98 per cent sulphuric acid and finally contacted with finely divided clay at 350 DEG F. Apparatus for carrying out the process may comprise a storage tank 1 from which the ore is supplied to a heated reaction vessel 3 into which air is blown through a pipe 4. The treated oil is passed through a cooler 5 and a storage tank 6 to an acid treating vessel 8, from which the raffinate is conducted to a clay treating vessel 12, the ore being circulated between the vessel 12 and a heating coil 13 to maintain the oil at the desired temperature. The product is passed through a filter 15 to a tank 16. U.S.A. Specification 1,927,823 is referred to.