Patent GB-648317-A (GB)
Title: Improvements in or relating to a process of synthesizing hydrocarbons
IPC: C07C1/04
Filed: 1947-08-08
Abstract: Hydrocarbons are synthesized from carbon monoxide and hydrogen by passing the gases upwardly through a powdered iron catalyst at such velocity as to maintain a dense turbulent phase superimposed by a light dispersed phase, withdrawing synthesis products from the latter, withdrawing part of the catalyst as a downwardly moving column directly from the dense phase and introducing it to an oxidizing zone wherein oxidizing gas is passed upwardly at such velocity as to maintain catalyst in dense turbulent phase under oxidation conditions, removing gases from the upper part of said zone, separately removing catalyst as a downwardly moving column, reducing it, and employing it for further synthesis.  The reduction <PICT:0648317/IV (b)/1> <PICT:0648317/IV (b)/2> may be effected in a reducing gas passed upwardly at such velocity as to maintain the catalyst in dense phase turbulent condition. Part or all of the reduced catalyst may be repeatedly subjected to the oxidizing and reducing treatment before return to the synthesis zone.  The oxidation and reduction steps may employ a multi-stage counter-current system wherein the catalyst at 400 DEG  F. or less moves downwards from stage to stage against the oxidizing gas stream and leaves at 1400-1600 DEG  F., then passing down against cold reducing gas introduced into the lowest stage of the reducer. Suitable catalysts are prepared from iron oxide, iron nitrate, precipitated iron carbonate or iron carbonyl by decomposition, addition of promoters, and in some cases carriers, and reduction, if desired after sintering.  They should have a particle size of mainly 10-200 m .  The synthesis gas preferably contains a 2 : 1 H2 : CO molar ratio and may be obtained from natural gas and oxygen, carbon dioxide and/or steam.  Synthesis is effected at about 450-650 DEG  F. and 50-500 or more p.s.i. in reactor 14. Catalyst is withdrawn by standpipe 44 and is dispersed into conduit 47 by oxidizing gas introduced at 49.  Oxidizer 48 operates at 750-2000 DEG  F., sulphur and carbon being removed as oxides and iron oxidized to ferric oxide. Standpipe 55 leads the catalyst to reducer 58, the reduced catalyst finally being returned to reactor 14 by standpipe 62 and conduit 65. Fig. 2 shows counter-current oxidizer and reducer 68, 78 respectively, catalyst being fed to the top zone by line 67 and flowing down through downcomers 73, 73a, 73b, &c., while oxidizing gas fed by line 71 passes through plates 72, 72a, 72b, &c. at a velocity to maintain the catalyst fluidized.  Oxidized catalyst passes by line 77 to the reducer at about 1200-1300 DEG  F. and leaves for recycling to the oxidizer or synthesizer.  The Specification as open to inspection under Sect. 91 comprises the desulphurization only of hydrocarbon or synthesis gases by contact with the iron catalyst.  This subject-matter does not appear in the Specification as accepted.ALSO:<PICT:0648317/III/1> <PICT:0648317/III/2> Hydrocarbons are synthesized from carbon monoxide and hydrogen by passing the gases upwardly through a powdered iron catalyst at such velocity as to maintain a dense turbulent phase superimposed by a light dispersed phase, withdrawing synthesis products from the latter, withdrawing part of the catalyst as a downwardly moving column directly from the dense phase and introducing it to an oxidizing zone wherein oxidizing gas is passed upwardly at such velocity as to maintain catalyst in dense turbulent phase under oxidation conditions, removing gases from the upper part of said zone, separately removing catalyst as a downwardly-moving column, reducing it and employing it for further synthesis.  The reduction may be effected in a reducing gas passed upwardly at such velocity as to maintain the catalyst in dense phase turbulent condition. Part or all of the reduced catalyst may be repeatedly subjective to the oxidizing and reducing treatment before return to the synthesis zone.  The oxidation and reduction steps may employ a multi-stage counter-current system wherein the catalyst at 400 DEG F. or less moves downwards from stage to stage against the oxidizing gas stream and leaves at 1400-1600 DEG  F., then passing down against cold reducing gas introduced into the lowest stage of the reducer. Suitable catalysts are prepared from iron oxide, iron nitrate, precipitated iron carbonate or iron carbonyl by decomposition, addition of promoters, and in some cases carriers, and reduction, if desired after sintering.  They should have a particle size of mainly 10-200 m .  Synthesis is effected at about 450-650 DEG  F. and 50-500 or more p.s.i. in reactor 14. Catalyst is withdrawn by standpipe 44 and is dispersed into conduit 47 by oxidizing gas introduced at 49. Oxidizer 48 operates at 750-2000 DEG  F., sulphur and carbon being removed as oxides and iron oxidized to ferric oxide.  Standpipe 55 leads the catalyst to reducer 58, the reduced catalyst finally being returned to reactor 14 by standpipe 62 and conduit 65.  Fig. 2 shows counter-current oxidizer and reducer 68, 78, respectively, catalyst being fed to the top zone by line 67 and flowing down through downcomers 73, 73a, 73b, &c. while oxidizing gas fed by line 71 passes through plates 72, 72a, 72b, &c. at a velocity to maintain the catalyst fluidized.  Oxidized catalyst passes by line 77 to the reducer at about 1200-1300 DEG  F. and leaves for recycling to the oxidizer or synthesizer.  The Specification as open to inspection under Sect. 91 comprises the desulphurization only of hydrocarbons or synthesis gases by contact with the iron catalyst.  This subject-matter does not appear in the Specification as accepted.