Patent GB-1059885-A (GB)
Title: Process for the removal, wholly or in part, of straight chain hydrocarbons from hydrocarbon mixtures
Inventor: VERNET CHARLES
IPC: C10G67/14
Filed: 1962-12-31
Abstract: In a process for the removal, wholly or in part, of straight chain hydrocarbons from hydrocarbon mixtures, a micro-organism capable of growth in the presence of a hydrocarbon feedstock consisting of a mixture of straight-chain hydrocarbons with other hydrocarbons is cultivated in the presence of the feedtock, an aqueous nutrient medium and a gas containing free oxygen, thereafter the micro-organism is separated from the hydrocarbon residue and the hydrocarbon residue is subjected to a caustic wash.  By the process waxes may be removed wholly or in part from a wax-containing petroleum gas oil, the gas oil of reduced wax content obtained, with or without an intervening refining treatment, being subjected to the caustic wash, whereby the unsatisfactory cloud point caused by esters formed during the cultivation is reduced. The straight-chain hydrocarbons may be paraffins and/or olefins.  The feedstock may be a petroleum fraction containing 3-45% by weight of straight chain hydrocarbons, kerosine, gas oils or lubricating oils, refined or unrefined.  There may be employed for the caustic wash (1) a 30-50% by weight aqueous solution of sodium or potassium hydroxide at a ratio of hydrocarbon to treating medium in the range 1 : 1 to 1 : 5 by volume, or (2) a 15-25% by weight alcoholic solution of sodium or potassium hydroxide at a ratio of hydrocarbon to treating medium in the range 2 : 1 to 1 : 2 by volume.  The caustic wash is carried out using a reaction temperature in the range 60-100 DEG  C., e.g. by boiling under reflux. Many species and strains of yeasts, moulds and bacteria are mentioned; the preferred micro-organism is Candida lipolytica.ALSO:In a process for the removal, wholly or in part, of straight chain hydrocarbons from hydrocarbon mixtures, a micro-organism capable of growth in the presence of a hydrocarbon feedstock consisting of a mixture of straight chain hydrocarbons with other hydrocarbons is cultivated in the presence of the feedstock, an aqueous nutrient medium and a gas containing free oxygen, thereafter the micro-organism is separated from the hydrocarbon residue and the hydrocarbon residue is subjected to a caustic wash.  By the process waxes may be removed wholly or in part from a wax-containg petroleum gas oil, the gas oil of reduced wax content obtained, with or without an intervening refining treatment, being subjected to the caustic wash, whereby the unsatisfactory cloud point caused by esters formed during the cultivation is reduced.  The straight chain hydrocarbons may be paraffins and/or olefins.  The feedstock may be petroleum fraction containing 3-45% by weight of straight chain hydrocarbons, kerosine, gas oils or lubricating oils, refined or unrefined. There may be employed for the caustic wash (1) a 30-50% by weight aqueous solution of sodium or potassium hydroxide at a ratio of hydrocarbon to treating medium in the range 1:1 to 1:5 by volume, or (2) a 15-25% by weight alcoholic solution of sodium or potassium hydroxide at a ratio of hydrocarbon to treating medium in the range 2;1 to 1;2 by volume. The caustic wash is carried out using a reaction temperature in the range 60-100 DEG C., e.g. by boiling under reflux.  Many species and strains of yeast, moulds and bacteria are mentioned; the preferred micro-organism is Candida hipolytica.