Methanation process with intermittent reactivation of catalyst
AssigneeUnion Oil Company of California
InventorHarry H. Dobashi
Life of this patent
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Abstract
A process is provided for the hydrogenation of carbon monoxide and/or carbon dioxide to form methane (methanation), using certain sulfur-sensitive nickel-alumina catalysts having a relatively low ratio of nickel surface area to nickel mass. It has been found that when such catalysts become deactivated as a result of sulfur poisoning, they can be reactivated to substantially fresh activity by reduction with hydrogen. Other nickel-alumina methanation catalysts having higher nickel surface areas are found to be essentially non-regenerable by hydrogen reduction following sulfur deactivation.
Claims10
A methanation process wherein:
- 1. a stream of contaminated feed gas comprising hydrogen and carbon monoxide and/or carbon dioxide is contacted with a nickel-alumina catalyst at temperatures between about 600.degree. and 1500.degree. F to produce methane;
- 2. said catalyst has a total nickel content between about 15 and 60% by weight, calculated as Ni, one portion of said nickel content being in an active metallic state, and another portion thereof being nickel aluminate, the nickel specific surface area of said catalyst in its freshly reduced state being between about 5 and 50 m.sup.2 /gm of Ni;
- 3. said feed gas is contaminated with H.sub.2 S or a sulfur compound which yields H.sub.2 S upon hydrogenation, whereby said catalyst becomes at least partially deactivated;
- 4. said deactivated catalyst is reactivated with essentially no removal of sulfur therefrom by contacting the same with a substantially sulfur-free stream of reactivating gas consisting essentially of hydrogen, said reactivation contacting being carried out at between about 800.degree. and 1500.degree. F and continued for at least about 5 hours;
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- 5. the resulting reactivated catalyst is again placed on-stream for methanation as defined in (1) above.
A methanation process wherein:
- 1. a stream of contaminated feed gas comprising hydrogen and carbon monoxide and/or carbon dioxide is contacted with a nickel-alumina catalyst at temperatures between about 600.degree. and 1500.degree. F to produce methane;
- 2. said catalyst has a total nickel content between about 25 and 50% by weight, calculated as Ni, one portion of said nickel content being in an active metallic state, and another portion thereof being nickel aluminate, the nickel specific surface area of said catalyst in its freshly reduced state being between about 10 and 35 m.sup.2 /gm of Ni;
- 3. said feed gas is contaminated with H.sub.2 S or a sulfur compound which yields H.sub.2 S upon hydrogenation, whereby said catalyst becomes at least partially deactivated;
- 4. said deactivated catalyst is reactivated with essentially no removal of sulfur therefrom by contacting the same with a substantially sulfur-free stream of reactivating gas consisting essentially of hydrogen, said reactivation contacting being carried out at between about 800.degree. and 1500.degree. F and continued for at least about 5 hours;
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- 5. the resulting catalyst is again placed on-stream for methanation as defined in (1) above.
Dependencies are inferred from the claim text.