Patent GB-1059884-A (GB)
Title: Process for the removal, wholly or in part, of straight chain hydrocarbons from hydrocarbon mixtures
Inventor: LAINE BERNARD MAURICE
IPC: C10G67/02
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 and 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 hydrogenation.  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 hydrogenated, 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.  The hydrogenation is carried out in the presence of a catalyst containing cobalt and molybdenum with or without iron, nickel metal, nickel/tungsten sulphide, or any other conventional hydrogenation or desulphurizing catalyst. There are employed for the hydrogenation a space velocity in the range 1-10 vol./vol./ hour, a hydrogen/hydrocarbon mole ratio in the range 0.1/ to 5/1, temperatures in the ranges 100-500 DEG  C. and pressures in the range 10-70 kgs./sq. cm.  Many species and strains of yeasts, moulds and bacteria are particularly mentioned.  According to an example, 40 litres of an aqueous mineral nutrient medium were introduced into a stainless steel fermenter kept at a temperature of 30 DEG  C., followed by 20 litres of inoculum from a culture of Candida lipolytica on mixed C9-C16 normal paraffinic hydrocarbons and 1.03 litres of heavy gas-oil. Agitation and aeration were such that the rate of aeration was 3 millimoles oxygen per litre of medium per minute.  The gas-oil recovered was washed with water, was dried by means of phosphorous pentoxide, and then was passed over 100 ml. of a conventional cobalt/molybdenum hydrogenation catalyst at a rate of 400 ml. per hour at 390 DEG  C. and a pressure of 70 kg. per sq. cm. with hydrogen at 100 ml. per hour.  The heavy gas-oil exhibited cloud points of +20 DEG  C. initially, +5 DEG  C. after recovery from the cultivated micro-organisms, and - 10 DEG  C. after the hydrogenation. In a further example, the micro-organism was continuously cultured in a medium containing 10% by weight of heavy gas-oil emulsified in 90% of the above-mentioned aqueous mineral medium.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 and 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 hydrogenation. 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 hydrogenated, 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.  The hydrogenation is carried out in the presence of a catalyst containing cobalt and molybdenum with or without iron, nickel meta, nickel/tungsten sulphide, or any other conventional hydrogenation or desulphurising catalyst.  There are employed for the hydrogenation a space velocity in the range 1-10 vol/vol/hour, a hydrogen/hydrocarbon mole ratio in the range 0.1/to 5/1, temperatures in the ranges 100-500 DEG C. and pressures in the range 10-70 kgs/sq. cm.  Many species and strains of yeasts, moulds and bacteria are particularly mentioned.  According to an example, 40 litres of an aqueous mineral nutrient medium consisting of diammonium phosphate, potassium chloride, magnesium sulphate, zinc sulphate, manganese sulphate, ferrous sulphate and yeast extract, were introduced into a stainless steel fermenter kept at a temperature of 30 DEG C. by water circulated through an external annulus.  20 litres inoculum from a culture of Candida lipolytica on mixed C9-C16 normal paraffinic hydrocarbons were then added such that the cellular density was about 1 gram/litre. 1.03 litres of heavy gas-oil, enough to carry the cellular density to 2 grams/litre, were then added to the fermenter.  The temperature of the culture was controlled at 30\sB1 DEG C., the pH at 4.  Agitation and aeration were such that the rate of aeration was 3 milli-moles oxygen per litre of medium per minute.  An automatic pH controller added 10 N ammonia when necessary. After 25 hours, when the cellular density was 18 grams/litre, a quantity of the culture was withdrawn from the fermenter, from which 300 millilitres of non-metabolized gas-oil was obtained by centrifuging at + 5 DEG C.  The gas-oil recovered was washed with water, was dried by means of phosphorous pentoxide, and then was passed over 100 ml. of a conventional cobalt/molybdenum hydrogenation catalyst at a rate of 400 ml. per hour at 390 DEG C. and a pressure of 70 kg. per sq. cm. with hydrogen at 100 ml. per hour.  The heavy gas-oil exhibited cloud points of + 20 DEG C. initially, + 5 DEG C. after recovery from the cultivated micro-organism was continuously cultured in a medium hydrogenation. In a further example, the micro-organism was continuously cultured in a medium containing 10% by weight of heavy gas-oil emulsified in 90% of the above-mentioned aqueous mineral medium.