Patent GB-675620-A (GB)
Title: Improvements in or relating to processes for the production of hydrocarbons and the hydrocarbons so produced
IPC: C10G69/04
Filed: 1950-04-12
Abstract: Alkyl benzothiophenes present in hydrocarbon fractions boiling between 180 DEG  and 375 DEG  C., obtained by catalytic cracking of a mineral oil material containing more than 0.75 per cent of sulphur, are converted into aromatics by hydrogenation in the presence of a desulphurizing catalyst which has no more than a slight tendency to hydrogenate aromatics, under conditions of temperature and pressure such that no substantial cracking of C-C bonds occurs.  The aromatic-rich products boil within the range of engine fuels of the nature of gasoline, kerosine and diesel oil.  The cracked fraction used as initial material preferably boils between 200 DEG  and 350 DEG  C.  The hydrogenation may be carried out in the vapour or liquid phase within the temperature range 320 DEG  to 425 DEG  C. and a pressure range of 20 to 200 atmospheres. Desirably the oil is allowed to flow in a thin layer over a stationary catalyst arranged in a vertical oven while passing a small volume of hydrogen through the oven.  The gas leaving the oven after removal of sulphuretted hydrogen should not exceed 500 litres (at N.T.P.) per volume of oil. A suitable catalyst consists of the oxides of cobalt and molybdenum supported on an aluminium oxide carrier (bauxite, activated alumina). Particularly suitable are catalysts with 5-10 per cent active metals and a cobalt : molybdenum ratio between 1 : 10 and 9 : 10, especially 1 : 5.  The carrier may be pretreated with hydrochloric acid.  Other suitable catalysts are listed in Specifications 488,651 and 657,400, [Group III].  In an example a "flashed" distillate of an oil having 2.5 per cent sulphur is catalytically cracked.  The fraction boiling between 205 DEG  and 300 DEG  C. (sulphur content 2.8 per cent) is hydrogenated at 375 DEG  C. and 50 atmospheres by trickling the oil at a speed of 2 kilograms per hour over a cobalt oxide-molybdenum oxide catalyst on alumina. The atomic ratio of cobalt to molybdenum is 1 : 5.  The volume of hydrogen having the reaction space per kilogram of initial material is 50 litres (at N.T.P.).  97 per cent by weight of a liquid reaction product containing 0.5 per cent sulphur is obtained.ALSO:Hydrocarbon fractions boiling between 180 DEG  and 375 DEG C obtained by catalytic cracking of a mineral oil material boiling above the gasoline range and containing more than 0.75 per cent of sulphur, are hydrogenated in the presence of a desulphurizing catalyst, which has no more than a slight tendency to hydrogenate aromatics, under conditions of temperature and pressure such that no substantial cracking of C-C bonds occurs but that the sulphur compounds present are decomposed with the formation of products boiling within the gasoline, kerosene or diesel oil engine fuel ranges.  The initial mineral oil material may be a kerosene or gas oil, and the cracked fraction preferably boils between 200 DEG and 350 DEG C The hydrogenation may be carried out in the vapour or liquid phase within the temperature range of 320 DEG  to 425 DEG C and a pressure range of 20 to 200 atmospheres Desirably the oil is allowed to flow in a thin layer over a stationary catalyst arranged in a vertical oven while passing a small volume of hydrogen through the oven.  The gas leaving the oven after removal of sulphuretted hydrogen should not exceed 500 litres (at N.T.P.) per kilogram of oil.  A suitable catalyst consists of the oxides of cobalt or molybdenum supported on an aluminium oxide carrier (bauxite, activated alumina).  Particularly suitable are catalysts with 5-10 per cent active metals, and a cobalt: molybdenum ratio between 1 : 10 and 9 : 10, especially 1 : 5.  The carrier may be pretreated with hydrochloric acid.  Other suitable catalysts are listed in Specifications 488,651 and 657,400.  Any alkyl benzothiophenes present in the initial material are decomposed to give aromatics. In examples (1) a "flashed" distillate of an oil having 2.5 per cent sulphur is catalytically cracked.  The fraction boiling between 205 DEG  and 300 DEG C (sulphur content 2.8 per cent) is hydrogenated at 375 DEG C and 50 atmospheres by trickling the oil at a speed of 2 kilograms per hour over a cobalt oxide-molybdenum oxide catalyst on alumina.  The atomic ratio of cobalt to molybdenum is 1 : 5.  The volume of hydrogen leaving the reaction space per kilogram of initial material is 50 litres (at N.T.P.). 97 per cent by weight of a liquid reaction product containing 0.15 per cent sulphur is obtained. Example (2) describes the treatment of a fraction from the same flashed distillate, said fraction boiling between 205 DEG  and 350 DEG C, of sulphur content 2.5 per cent. The desulphurized product has a sulphur content of 0.39 per cent. By sharp rectification this product was split into several fractions: 7 per cent formed a fraction boiling up to 205 DEG C (aromatics 81 per cent by volume), and a further 7 per cent boiled between 205 DEG  and 220 DEG C (aromatics 75 per cent by volume).  These were combined to give a product of octane number 86 (C.F.R. motor method).  A further 6 per cent boiled between 220 DEG  and 230 DEG C, and a further 17 per cent between 230 DEG  and 260 DEG C.  These were combined and mixed with an equal weight of straight-run gasoline (B.P. 140-220 DEG C) to give a motor kerosene of octane number 50 (C.F.R. motor method).  The remaining 63 per cent boiling above 260 DEG C had a Diesel index of 41 and could be used as a Diesel oil.