Char Methanation Catalyst and its Use in Gasification Processes

• US 20100121125A1
• Filed: 09/18/2009
• Published: 05/13/2010
• Est. Priority Date: 09/19/2008
• Status: Active Grant

• Current Assignee: Sure Champion Investments Limited
• Original Assignee: GreatPoint Energy, Inc.
• Inventors: Hippo, Edwin J., Robinson, Earl T., Smith, Jeffery, Raman, Pattabhi K., Reiling, Vincent G., Mims, Charles, Nahas, Nicholas Charles
• Granted Patent: US 8,502,007 B2
• Time in Patent Office: Days
• US Class Current: 585/733
• CPC Class Codes: B01J 21/18 Carbon
• CPC Class Codes: B01J 21/20 Regeneration or reactivation
• CPC Class Codes: B01J 23/04 Alkali metals
• CPC Class Codes: B01J 23/92 of catalysts comprising metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
• CPC Class Codes: B01J 35/31 Density
• CPC Class Codes: B01J 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: B01J 35/613 10-100 m2/g
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 37/009 Preparation by separation, e.g. by filtration, decantation, screening
• CPC Class Codes: B01J 37/0201 Impregnation
• CPC Class Codes: B01J 38/72 including segregation of diverse particles
• CPC Class Codes: C10J 2300/093 Coal
• CPC Class Codes: C10J 2300/0956 Air or oxygen enriched air
• CPC Class Codes: C10J 2300/0959 Oxygen
• CPC Class Codes: C10J 2300/0973 Water
• CPC Class Codes: C10J 2300/0986 Catalysts
• CPC Class Codes: C10J 2300/1662 to methane (SNG) production of synthetic natural gas C10L3/08
• CPC Class Codes: C10J 2300/1671 with the production of electricity
• CPC Class Codes: C10J 2300/1675 making use of a steam turbine
• CPC Class Codes: C10J 2300/1687 with steam generation
• CPC Class Codes: C10J 2300/1807 : Recycle loops, e.g. gas, solids, heating medium, water
• CPC Class Codes: C10J 2300/1884 : with one stream being synthesis gas
• CPC Class Codes: C10J 3/00 : Production of combustible gases containing carbon monoxide from solid carbonaceous fuels destructive distillation processes C10B
• CPC Class Codes: C10J 3/482 : Gasifiers with stationary fluidised bed
• CPC Class Codes: C10L 3/08 : Production of synthetic natural gas
• CPC Class Codes: Y02P 20/52 : using catalysts, e.g. selective catalysts
• CPC Class Codes: Y02P 20/584 : Recycling of catalysts

Abstract

The invention provides processes for generating a methane-enriched gas from a gas mixture comprising carbon monoxide and hydrogen such as gas streams generated by gasification of an alkali metal catalyst-loaded carbonaceous feedstock, and a char methanation catalyst useful in such processes.

Claims

1. A process for the production of a methane-enriched gas, comprising the steps of:

(a) introducing a gaseous mixture comprising hydrogen and carbon monoxide into a reaction zone containing a carbon-alkali metal methanation catalyst,

(b) reacting at least a portion of the hydrogen with at least a portion of the carbon monoxide in the reaction zone, under suitable temperature and pressure, in the presence of the carbon-alkali metal methanation catalyst, to produce a methane-enriched gaseous mixture, and

(c) recovering a methane-enriched gas from the reaction zone,

wherein the carbon-alkali metal methanation catalyst comprises a carbon char comprising a carbon content and an ash content, the carbon content being from about 25% to about 75% (by weight, dry basis), the carbon char further comprising;

(i) a total elemental oxide content of from about 65% to about 98% (based on the weight of the ash content, dry basis),

(ii) a molar ratio of alkali metal to carbon (AIM/C) of from about 0.1 to about 0.6,

(iii) a BET surface area of from about 10 to about 400 m²/g,

(iv) an average particle size of from about 25 μ

m to about 2500 μ

m, and

(v) an average particle density of from about 0.2 to about 1.75 g/cc.

2. The process of claim 1, wherein the carbon char is prepared by gasifying a carbonaceous material in the presence of steam and an alkali metal gasification catalyst.

3. The process of claim 1, wherein the carbon char is a solid by-product resulting from the gasification of a carbonaceous material in the presence of steam and an alkali metal gasification catalyst.

4. The process of claim 1, wherein the alkali metal is potassium.

5. The process of claim 1, wherein the gaseous mixture in step (a) is a gaseous product stream obtained from the gasification of a carbonaceous material in a gasifying reactor in the presence of steam and an alkali metal gasification catalyst.

6. The process of claim 5, wherein the alkali metal is potassium.

7. A process for the production of a methane-enriched gaseous product, comprising the steps of:

(a) gasifying a carbonaceous material in a gasifying reactor, in the presence of steam and an alkali metal gasification catalyst, to produce a gaseous product stream and an alkali metal-containing solid char product;

(b) withdrawing the alkali metal-containing solid char product from the gasifying reactor;

(c) introducing a gaseous mixture comprising hydrogen and carbon monoxide into a reaction zone containing at least a portion of the alkali metal-containing solid char product as a methanation catalyst,

(d) reacting at least a portion of the hydrogen with at least a portion of the carbon monoxide in the reaction zone, under suitable temperature and pressure, in the presence of the alkali metal-containing solid char product to produce a methane-enriched gaseous product, and

(e) recovering a methane-enriched gaseous product from the reaction zone.

8. The process of claim 7, wherein the alkali metal-containing char product comprises a carbon content and an ash content, the carbon content being from about 25% to about 75% (by weight, dry basis), the alkali metal-containing char product further comprising:

(i) a total elemental oxide content of from about 65% to about 98% (based on the weight of the ash content, dry basis),

(ii) a molar ratio of alkali metal to carbon of from about 0.1 to about 0.6,

(iii) a BET surface area of from about 10 to about 400 m²/g,

(iv) an average particle size of from about 25 to about 2500 μ

m, and

(v) an average particle density of from about 0.2 to about 1.75 g/cc.

9. The process of claim 7, wherein the gaseous mixture in step (c) is the gaseous product stream from step (a).

10. The process of claim 9, wherein the gaseous product stream comprises methane, carbon monoxide, carbon dioxide and hydrogen.

11. The process of claim 10, wherein the gaseous product stream comprises at least about 20 mol % methane based on the moles of methane, carbon dioxide, carbon monoxide and hydrogen in the second gas stream.

12. The process of claim 11, wherein the gaseous product stream comprises at least about 50 mol % methane plus carbon dioxide, based on the moles of methane, carbon dioxide, carbon monoxide and hydrogen in the second gas stream.

13. The process of claim 8, wherein the gaseous mixture in step (c) is the gaseous product stream from step (a).

14. The process of claim 13, wherein the gaseous product stream comprises methane, carbon monoxide, carbon dioxide and hydrogen.

15. The process of claim 14, wherein the gaseous product stream comprises at least about 20 mol % methane based on the moles of methane, carbon dioxide, carbon monoxide and hydrogen in the second gas stream.

16. The process of claim 15, wherein the gaseous product stream comprises at least about 50 mol % methane plus carbon dioxide, based on the moles of methane, carbon dioxide, carbon monoxide and hydrogen in the second gas stream.