Gas purification configurations and methods

• US 8,876,951 B2
• Filed: 09/29/2010
• Issued: 11/04/2014
• Est. Priority Date: 09/29/2009
• Status: Active Grant

• Current Assignee: Fluor Technologies Corporation (Fluor Corporation)
• Original Assignee: Fluor Technologies Corporation (Fluor Corporation)
• Inventors: Mak, John
• Primary Examiner(s): Jones, Christopher P
• Application Number:
  US13/498,084
• Publication Number:
  US 20130032029A1
• Time in Patent Office: 1,497 Days
• Field of Search: 95/92, 95/94, 951/36, 962/34, 926/18
• US Class Current: 95/92
• CPC Class Codes: B01D 2252/2026 Polyethylene glycol, ethers or esters thereof, e.g. Selexol
• CPC Class Codes: B01D 2252/20447 containing a piperazine-ring
• CPC Class Codes: B01D 2252/20468 containing a pyrrolidone-ring
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2256/22 Carbon dioxide
• CPC Class Codes: B01D 2257/304 Hydrogen sulfide
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2257/702 Hydrocarbons
• CPC Class Codes: B01D 2259/40086 by using a purge gas B01D2259/4009 takes precedence
• CPC Class Codes: B01D 53/0462 Temperature swing adsorption
• CPC Class Codes: B01D 53/1462 Removing mixtures of hydrogen sulfide and carbon dioxide
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: C10L 2290/544 Extraction for separating fractions, components or impurities during preparation or upgrading of a fuel
• CPC Class Codes: C10L 3/103 Sulfur containing contaminants
• CPC Class Codes: C10L 3/104 Carbon dioxide
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

Acid gas is removed from a feed gas in an absorber that produces a treated feed gas and a rich solvent. The treated feed gas is passed through an H2S scavenger bed, and the H2S scavenger bed is regenerated using H2S depleted acid gas flashed from the rich solvent. Most preferably, the off gas from the regenerating bed is injected into a formation.

Claims

1. A method of treating a feed gas that includes CO2 and H2S, comprising:

removing in an absorber CO2 from a feed gas using a flashed lean physical solvent to so form a treated gas and a rich solvent;

removing H2S from the treated gas using a molecular sieve bed to thereby form an H2S loaded molecular sieve bed;

flashing the rich solvent to produce the flashed lean solvent and a CO2-rich stream; and

regenerating the H2S loaded molecular sieve bed using the CO2-rich stream to thereby form an H2S-enriched CO2 product.

2. The method of claim 1 wherein H2S is removed from the CO2-rich stream prior to the step of regenerating the H2S loaded molecular sieve bed using an additional molecular sieve bed.

3. The method of claim 1 further comprising a step of removing water from the H2S-enriched CO2 product.

4. The method of claim 3 further comprising a step of compressing and re-injecting the H2S-enriched CO2 product.

5. The method of claim 1 further comprising a step of heating the CO2-rich stream for the step of regenerating the H2S loaded molecular sieve bed.

6. The method of claim 1 wherein the step of flashing the rich solvent comprises a step of vacuum flashing.

7. The method of claim 1 wherein the step of flashing the rich solvent is performed over multiple flashing stages, and wherein at least one of the multiple flashing stages produces a hydrocarbon-enriched vapor.

8. The method of claim 7 further comprising a step of compressing the hydrocarbon-enriched vapor and combining the compressed hydrocarbon-enriched vapor with the feed gas.

9. The method of claim 1 wherein substantially all of the CO2-rich stream is formed from the rich solvent without heating the rich solvent.

10. The method of claim 1 wherein the feed gas is dehydrated and chilled to condense and remove C5+ hydrocarbons from the feed gas.

11. A method of regenerating an H2S loaded molecular sieve bed, comprising:

contacting a molecular sieve bed with a treated feed gas from which CO2 has been removed to so form the H2S loaded molecular sieve bed; and

contacting the H2S loaded molecular sieve bed with the CO2 to thereby regenerate the molecular sieve bed and to thereby form an H2S-enriched CO2 product.

12. The method of claim 11 wherein H2S has been removed from the CO2 using an additional molecular sieve bed prior to the step of contacting the H2S loaded molecular sieve bed with the CO2.

13. The method of claim 11 further comprising a step of condensing and removing water from the H2S-enriched CO2 product.

14. The method of claim 11 further comprising a step of re-injecting the H2S-enriched CO2 product.