Patent GB-479428-A (GB)
Title: Improvements in methods for the hydrogenation of hydrocarbons containing sulphur
IPC: C10G47/00
Filed: 1936-05-29
Abstract: <PICT:0479428/III/1> <PICT:0479428/III/2> Hydrocarbons containing sulphur are purified and converted into hydrocarbons of lower B.P. and M.W., with or without cracking, by hydrogenation in presence of catalysts not poisoned by sulphur, the hydrogenation being effected in a series of steps in successive catalytic chambers, the hydrogen sulphide content of the mixture issuing from each catalytic chamber being maintained between 0,1 and 1,0 per cent, and this hydrogen sulphide above 0,1 per cent being eliminated by absorbing substances in separate chambers before the mixture passes to the next catalytic chamber.  The activity of the catalyst is thus maintained at a maximum.  A suitable catalyst is a colloidal precipitate of molybdic, tungstic, or vanadic acid adsorbed on active carbon. The hydrogenation may be effected at atmospheric or higher pressure, e.g. up to more than 300 atmospheres, at 200 to above 600 DEG  C., in the liquid or vapour phase, and with hydrogen or hydrogenating gases. The absorption of hydrogen sulphide is effected physically, e.g. by adsorption, or chemically as by metals, oxides, or metallic salts; suitable metals are iron, nickel, cobalt, copper, manganese, antimony, tin, zinc, lead, aluminium, alloys of any 2 or more, cast iron or steel, preferably as powder, wire-gauze, turnings, or scrap; oxides specified are lime, magnesia, baryta, and oxides of iron, manganese, copper, zinc, chromium, nickel, cobalt, aluminium, lead, sodium, or potassium; suitable salts are natural carbonates or silicates of the metals of the above oxides, earths containing these metals or oxides, and the sub-sulphides of copper, antimony, bismuth, manganese, nickel, or cobalt.  The absorbents may be regenerated by treatment with steam, water-gas, residual hydrogen, air, or oxygen. Conveniently, a mixture of hydrocarbon vapour with hydrogenating gas is passed through a pipe 1, a vertical or horizontal tube 2 containing the catalyst, a tube 3 containing absorbent, and further tubes 2, 3 to an outlet 4; the used absorbent is regenerated by desulphurizing gases introduced by a pipe 5 and discharged through a pipe 6.  Each tube 3 may be replaced by tubes 3a, 3b which are used alternately so as to make the process continuous; the change-over may be effected automatically, e.g. by valves controlled by the composition of the gases issuing from the absorbers.  Should the absorbents reduce the proportion of hydrogen sulphide entering a hydrogenating tube below 0,1 per cent: (1) hydrogen sulphide may be added; or (2) receptacles containing a reducible sulphide, e.g. of copper or antimony, may be inserted between the chambers 3, 2 and a suitable byepass provided; or (3) the temperature of the chambers 3 may be lowered; or (4) the chambers 3 may be filled with different absorbents, or with the same absorbent in different states of saturation; or (5) an adjustable portion of the mixture may be sent through a byepass 11 direct from one chamber 2 to the next. The devices effecting this alteration of the residual hydrogen sulphide content may be controlled automatically.  The heating may be electric, by hot gases, or by that produced in the absorption chambers; suitably one or more chambers 3, with or without other heat-exchangers, are arranged as heat-exchangers in the pipe 1.  The crude oil may be divided into heavy and light fractions each of which is purified by hydrogenation at low pressure; the heavy fraction may be again fractionated and the fractions hydrogenated; the final heavy oil may then be submitted to high-pressure hydrogenation, fractionally distilled, and the heavy portion recirculated until converted wholly into light hydrocarbons.  In an example, 1000 litres of schist and oil containing 5 per cent of sulphur is converted into 1000--1050 litres of sulphur-free petrol; less than 1 per cent of methane is produced.