Patent GB-484127-A (GB)
Title: Improvements in or relating to the production of valuable hydrocarbon products by the treatment with hydrogenating gases of liquid or semi-liquid carbonaceous materials
Filed: 1936-11-27
Abstract: Valuable hydrocarbon products, e.g. lubricating-oil, Diesel oil, and motor fuels are obtained from initial materials comprising liquid, semi-solid, or fusible distillable carbonaceous materials by treating the materials in the liquid phase with hydrogenating gases in the presence of hydrogenating catalysts in a concentration of at least 10 per cent with a throughput of 0,2 to 1,5 kilograms of material per litre of reaction space and under pressures of at least 50 atmos, and temperatures between 270 and 420 DEG  C., the said conditions being co-ordinated so that the content of asphaltic substances is reduced by at least 90 per cent and less than 5 per cent of gaseous hydrocarbons and less than 25 per cent of products boiling below 350 DEG  C. are formed.  The process is referred to as "low temperature" hydrogenation and may be followed by further hydrogenation under more drastic conditions.  The reaction temperature is preferably maintained below 380 DEG  C. until the asphalt content of the reacting materials is reduced below 2 per cent.  The temperature of the reaction zone, which may comprise a series of reaction vessels, is preferably increased and decreased in steps in "saw toothed" fashion so that the final temperature is 80-100 DEG  C. higher than the initial but temperatures above 380 DEG  C. should only be employed for less than one fifth of the total reaction time.  The temperature is regulated by the introduction of cooling gases or oils or by cooling conduits between reaction vessels.  1000-5000 Cubic metres of hydrogen are employed per ton of material treated. In the process asphaltic substances are reduced without fouling the catalyst which may therefore be stationarily arranged in the reaction space and in concentration up to 100 per cent of the reaction space. Materials containing up to 20 per cent asphalt may be treated and the suitability of the material for treatment may be determined (a) by microscopic inspection-a material which is clear and homogeneous under a microscope with a magnification of 200-300 is suitable, (b) by distillation under vacuo without foaming before reaching a temperature of 325 DEG  C.  Materials not complying with the above requirements may be made suitable for treatment (a) by a refining hydrogenation at temperatures below 300 DEG  C. (b) by treatment with selective solvents, (c) by addition of diluents, e.g. cyclic hydrocarbons unaffected by the subsequent treatment which can be employed cyclically, e.g. naphthalene, anthracene, pyrene; hydrogenated polynuclear aromatic hydrocarbons, e.g. tetrahydronaphthalene; tars and tar middle oils the oxygen contents of which are reduced in the process.  The low temperature hydrogenation stage is preferably carried out in presence of diluents poor in hydrogen and the further stages in presence of diluents rich in hydrogen.  The usual hydrogenation catalysts may be employed particularly sulphides prepared by decomposition of thio salts or by sulphidizing at high temperatures or by precipitating polysulphides from solution. Catalysts of weak hydrogenating activity are preferably used in the first stages followed by catalysts of strong hydrogenating activity in the later stages.  The low temperature hydrogenation products may be worked up (a) by elimination of wax to give lubricating oil and by subsequent hydrogenation of the wax (b) by distillation into fractions of high octane and cetene numbers.  In examples:  (1) Brown coal low temperature tar of sp. gr. 0,952 and containing 7 per cent asphalt and 50 per cent middle oil is hydrogenated at 350 DEG  C. in presence of a catalyst comprising molybdic acid, zinc oxide, and magnesia which has been pretreated at 400 DEG  C. with hydrogen sulphide, with a throughput of 0,6 kg. initial material per litre catalyst space per hour.  A product of sp. gr. 0,880 and containing 7 per cent gasoline, 44 per cent middle oil, and 49 per cent heavy oil free from asphalt is obtained, 3 per cent gases being also formed.  The product is further treated at 360 DEG C. with hydrogen in presence of tungsten disulphide as catalyst and a product is obtained of sp. gr. 0,830 and containing 9 per cent gasoline, 52 per cent middle oil, and 39 per cent heavy oil.  23,5 Per cent wax is separated from the heavy oil giving a lubricating oil having a viscosity index of 57.  (2) A heavy coal oil containing 11,4 per cent asphalt is diluted with its own weight of tetrahydronaphthalene mixed with 2 per cent fuller's earth treated with ammonium bicarbonate and filtered. The filtrate is then similarly treated with hydrogen at 340-365 DEG  with a throughput of 0,25 kg. per litre catalyst space per hour. The products are diluted with their own weight of decahydronaphthalene and hydrogenated at 380-405 DEG  C. in presence of tungsten disulphide and a lubricating oil of Engler viscosity 1,6. and viscosity index 63 is obtained.  (3) A brown-coal tar is treated and a residue boiling above 325 DEG  C. is dewaxed with propane and the hard and soft wax obtained is destructively hydrogenated at 410 DEG  C. in presence of tungsten disulphide on bleaching earth pretreated with hydrogen fluoride.  (6) In the hydrogenation of a brown-coal tar, the temperatures are regulated so that they increase in the first vessel from 340-360 DEG C., in the first half of the second vessel from 360-380 DEG  C. and in the second half of the second vessel from 380-410 DEG  C.  (7) In the hydrogenation of a browncoal tar the temperature of the reaction is controlled by the introduction of cooling agents so that the temperature graph follows a sawtoothed line and the following successive temperatures are obtained-352-347-365-359-373 DEG  C. Definition.-A catalyst is said to have strong hydrogenating activity if it is capable of bringing per litre reaction space from 150-250 litres of hydrogen into reaction in the hydrogenation of a middle oil of sp. gr. 0,840 and b.p. range 200-350 DEG  C., which is passed at 405 DEG  C. and 200 atmos. pressure over the stationarily arranged catalyst in question with a throughput of 1,5 kg. oil per litre of catalyst per hour and 3 cubic metres of hydrogen per kg. oil.