Hydromethanation of a carbonaceous feedstock

• US 9,127,221 B2
• Filed: 05/31/2012
• Issued: 09/08/2015
• Est. Priority Date: 06/03/2011
• Status: Active Grant

• Current Assignee: Sure Champion Investments Limited
• Original Assignee: GreatPoint Energy, Inc.
• Inventors: Sirdeshpande, Avinash
• Primary Examiner(s): Akram, Imran
• Application Number:
  US13/484,918
• Publication Number:
  US 20120305848A1
• Time in Patent Office: 1,195 Days
• US Class Current: 1/1
• CPC Class Codes: C10J 2300/0903 Feed preparation
• CPC Class Codes: C10J 2300/093 Coal
• CPC Class Codes: C10J 2300/0956 Air or oxygen enriched air
• CPC Class Codes: C10J 2300/0976 as steam
• CPC Class Codes: C10J 2300/0986 Catalysts
• CPC Class Codes: C10J 2300/1621 Compression of synthesis gas
• CPC Class Codes: C10J 2300/1628 Ash post-treatment
• CPC Class Codes: C10J 2300/1823 for synthesis gas
• CPC Class Codes: C10J 3/463 in stationary fluidised beds
• CPC Class Codes: C10K 1/003 of acid contaminants, e.g. acid gas removal
• CPC Class Codes: C10K 1/04 by cooling to condense non-gaseous materials C10K1/001 takes precedence

Abstract

The present invention relates to processes for hydromethanating a carbonaceous feedstock to an acid gas-depleted methane-enriched synthesis gas, with improved efficiency of the acid gas removal treatment.

Claims

1. A process for generating a sweetened gas stream from a non-gaseous carbonaceous material, the process comprising the steps of:

(a) preparing a carbonaceous feedstock from the non-gaseous carbonaceous material;

(b) introducing the carbonaceous feedstock and a hydromethanation catalyst into a hydromethanation reactor;

(c) reacting the carbonaceous feedstock in the hydromethanation reactor at a first pressure condition in the presence of carbon monoxide, hydrogen, steam and hydromethanation catalyst to produce a methane-enriched raw product gas and a solid by-product char;

(d) withdrawing a methane-enriched raw product gas stream of the methane-enriched raw product gas from the hydromethanation reactor, wherein the methane-enriched raw product gas stream comprises methane, carbon monoxide, hydrogen, carbon dioxide, hydrogen sulfide, steam and heat energy;

(e) introducing the methane-enriched raw product stream is introduced into a first heat exchanger unit to recover heat energy and generate a cooled methane-enriched raw product stream;

(f) optionally steam shifting at least a portion of the carbon monoxide in the cooled methane-enriched raw product stream to generate a hydrogen-enriched raw product stream;

(g) dehydrating the cooled methane-enriched raw product stream, or if present the hydrogen-enriched raw product stream, to generate a substantially dehydrated raw product stream;

(h) compressing the dehydrated raw product stream to a second pressure condition to generate a compressed dehydrated raw product stream, wherein the second pressure condition is higher than the first pressure condition; and

(i) removing a substantial portion of the carbon dioxide and a substantial portion of the hydrogen sulfide from the compressed dehydrated raw product stream to produce the sweetened gas stream, wherein the sweetened gas stream comprises a substantial portion of the hydrogen, carbon monoxide (if present in the compressed dehydrated raw product stream) and methane from the compressed dehydrated raw product stream.

2. The process of claim 1, wherein the first pressure condition is about 600 psig (about 4238 kPa) or less.

3. The process of claim 2, wherein the first pressure condition is about 400 psig (about 2860 kPa) or greater.

4. The process of claim 2 wherein the second pressure condition is about 720 psig (about 5066 kPa) or greater.

5. The process of claim 4, wherein the second pressure condition is about 1000 psig or less (about 6996 kPa).

6. The process of claim 1, wherein the first pressure condition is about 400 psig (about 2860 kPa) or greater.

7. The process of claim 1, wherein the second pressure condition is about 720 psig (about 5066 kPa) or greater.

8. The process of claim 7, wherein the second pressure condition is about 1000 psig or less (about 6996 kPa).

9. The process of claim 1, wherein the second pressure condition is about 1000 psig or less (about 6996 kPa).

10. The process of claim 1, wherein the second pressure condition is about 20% higher or greater than the first pressure condition.

11. The process of claim 10, wherein the second pressure condition is about 35% higher or greater than the first pressure condition.

12. The process of claim 10, wherein the first pressure condition is about 600 psig (about 4238 kPa) or less;

the first pressure condition is about 400 psig (about 2860 kPa) or greater;

the second pressure condition is about 720 psig (about 5066 kPa) or greater; and

the second pressure condition is about 1000 psig or less (about 6996 kPa).

13. The process of claim 11, wherein the second pressure condition is about 50% higher or greater than the first pressure condition.

14. The process of claim 11, wherein the first pressure condition is about 600 psig (about 4238 kPa) or less;

the first pressure condition is about 400 psig (about 2860 kPa) or greater;

the second pressure condition is about 720 psig (about 5066 kPa) or greater; and

the second pressure condition is about 1000 psig or less (about 6996 kPa).

15. The process of claim 13, wherein the second pressure condition is less than or about equal to 100% higher than the first pressure condition.

16. The process of claim 13, wherein the first pressure condition is about 600 psig (about 4238 kPa) or less;

the first pressure condition is about 400 psig (about 2860 kPa) or greater;

the second pressure condition is about 720 psig (about 5066 kPa) or greater; and

the second pressure condition is about 1000 psig or less (about 6996 kPa).