Patent GB-714584-A (GB)
Title: Combination sulphurisation/hydrogen sulphide adsorption process
Inventor: EVANS ERIC BERTRAM
IPC: C10K1/26
Filed: 1951-02-20
Abstract: In a combination process for the sulphurization of organic material such as terpenes (dipentene and alpha-pinene) or the production of thiophenes as in Specification 696,439 where two molar proportions of a mono-olefin or vinyl compound react with one atomic proportion of sulphur, which sulphurizations evolve hydrogen sulphide, and for the stripping of hydrogen sulphide from a gas mixture containing it, which mixture contains a proportion of the hydrogen sulphide evolved in the sulphurization reaction, the gas mixture containing hydrogen sulphide is passed through a bed of iron oxide to deposit sulphur thereon, the spent oxide is passed to the sulphurization reactor to supply sulphur thereto, and the regenerated iron oxide is returned to the hydrogen sulphide adsorption stage.  Gas streams from other sources such as oil refineries, gas works or tar distilleries may supply some of the hydrogen sulphide to be converted to sulphur.  The process which preferably takes place in vapour phase may be wholly fluidized.  The organic material, for example styrene, is then passed in vapour phase through a fluidized bed of sulphur supported on iron oxide, together with the catalyst which may be added separated, mixed with the feed, supported on the iron oxide or on some other support. The relatively sulphur-free oxide gravitates to the bottom and is withdrawn as a suspension in air and steam and passed to the adsorption stage.  The effluent gases from the sulphurization, for example styrene, diphenyl thiophene and hydrogen sulphide, are cooled and condensed, the hydrogen sulphide passing to the adsorption stage together with sufficient air or steam to oxidize the hydrogen sulphide to sulphur, and to fluidize the iron oxide.  The sulphurized oxide is removed from the top of the bed and returned to the sulphurization reactor as a suspension in nitrogen or flue gas.  The catalyst for the production of thiophene may be conventional rubber vulcanization accelerators such as alkyl or aryl mercaptans, xanthates, condensation products of aromatic amines with aliphatic aldehydes, mercaptobenzathiazole or diphenylguanidine.  The iron oxide, which may carry the catalyst, may itself be supported on silica gel.  Superheated steam may be used to assist volatilization of high boiling point products in the sulphurization reaction and if molten sulphur impedes fluidization an inert powdered diluent such as sand or clay may be added.  Specifications 554,227, 568,913; 586,914 590,456, 601,723, 623,264, and 712,618, [all in Group III] also are referred to.ALSO:In a combination process for the sulphurization of organic materials, such as fatty oils, such as lard or sperm oil, which sulphurization evolves hydrogen sulphide, and for stripping hydrogen sulphide from a gas mixture containing it, which mixture contains a proportion of the hydrogen sulphide evolved in the sulphurization reaction, the gas mixture is passed through a bed of iron oxide particles to strip the hydrogen sulphide and to deposit elemented sulphur on the oxide particles, which are then passed to the sulphurization reactor where they are contacted with the organic materials in the presence of a sulphurization catalyst thereby regenerating the iron oxide which is recycled to the hydrogen sulphide adsorption stage.  The process is also applicable to the sulphurization of petroleum fractions to remove mono- and diolefinic compounds as described in Specification 712,618.  Gas streams from other sources such as oil refineries, gas works or tar distilleries may supply some of the hydrogen sulphide to be converted to sulphur. The process which preferably takes place in the vapour phase, may be operated wholly on the fluidized technique.  The organic materials are then passed in vapour phase through a fluidized bed of sulphur supported on iron oxide in the presence of a catalyst.  The relatively sulphur-free oxide gravitates to the bottom and is removed as a light suspension in an air steam mixture and passed to the hydrogen sulphide adsorption stage.  The effluent gases from the sulphurization reaction are separated and the hydrogen sulphide and inert gases therefrom are employed to fluidize the iron oxide in the adsorption stage together with sufficient air or steam to oxidize the hydrogen sulphide.  The sulphurized oxide concentrates at the top of the bed, stratification being assisted by the inclusion of non-fluidized packings such as lumps of refractory, and is withdrawn as a nitrogen or flue gas suspension and returned to the reactor. The process is also applicable to the sulphurization of terpenes such as dipentene or alphapinene or to the production of thiophenes from mono-olefins or vinyl compounds as described in Specification 696,439, [Group IV (b)]. Conventional vulcanization accelerators such as alkyl or aryl mercaptans, or xanthates, condensation products of aromatic amines and aliphatic aldehydes, mercaptobenzothialyde and diphenylquanidine may be used as catalysts in the latter case. These may be introduced separately or mixed with the feed, carried on an inert support or supported on the iron oxide.  Further the iron oxide may itself be supported on a silica gel support and the catalyst incorporated.  Such a catalyst may be prepared by impregnating a silica hydrosol with a ferric salt, precipitating with ammonia, washing and calcining.  One per cent. of mercaptobenzothiazole may then be deposited from ethanol solution. An inert powdered diluent may be added to the sulphurization reactor if the presence of molten sulphur impedes fluidization. Specifications 554,227, 568,913, 586,914, 590,456, 601,723, 623,264 also are referred to.