Removal of acid gases from gas mixtures using ion exchange resins

• US 5,797,979 A
• Filed: 01/23/1997
• Issued: 08/25/1998
• Est. Priority Date: 01/23/1997
• Status: Expired due to Term

• Current Assignee: National Institute for Strategic Technology Acquisition and Commercialization
• Original Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Inventors: Quinn, Robert
• Primary Examiner(s): SMITH, DUANE
• Application Number:
  US08/787,844
• Time in Patent Office: 579 Days
• Field of Search: 95/136, 95/139, 95/135, 95/137, 95/95, 95/97, 95/102, 95/148, 96/153, 96/108, 96/143, 96/144
• US Class Current: 95/97
• CPC Class Codes: B01D 2253/206 Ion exchange resins
• CPC Class Codes: B01D 2257/304 Hydrogen sulfide
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2259/40086 by using a purge gas B01D2259/4009 takes precedence
• CPC Class Codes: B01D 2259/4525 for storage and dispensing systems
• CPC Class Codes: B01D 53/02 by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: B01D 53/0446 Means for feeding or distributing gases
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A process is provided for selectively removing acid gases from a gas mixture by contacting said gas mixture with an anion exchange resin containing quaternary ammonium functionalities and moderately basic counteranions. The absorption process is reversible and the absorbent can be regenerated using an inert gas purge or by applying a vacuum.

Claims

1. A process for separating one or more acid gases from a gas stream containing said acid gas and at least one other component, comprising bringing said gas stream into contact with a macroreticular anion exchange resin containing quaternary ammonium functionalities and counter-anions which are the conjugate bases of acids having a pKa greater than 3 and less than 14, which anion exchange resin selectively absorbs, and thereby removes, said acid gas from the gas stream.

2. A process in accordance with claim 1 wherein said acid gas is selected from the group consisting of CO₂, H₂ S and mixtures thereof.

3. A process in accordance with claim 1 wherein said counter-anions are selected from the group consisting of fluoride, acetate and mixtures thereof.

4. A process in accordance with claim 1 wherein said anion exchange resin is utilized in the form of small beads consisting of a crosslinked polymer material.

5. A process in accordance with claim 2 wherein said gas mixture also contains a component selected from the group consisting of H₂, CH₄, N₂, O₂, CO, Ar and mixtures thereof.

6. A process in accordance with claim 1 which further comprises regenerating the anion exchange resin by desorbing the acid gas.

7. A process in accordance with claim 6 wherein said acid gas is desorbed from the anion exchange resin by reducing the pressure of acid gas above the absorbent by purging with an inert gas at ambient or slightly elevated temperature.

8. A process in accordance with claim 6 wherein said acid gas is desorbed from the anion exchange resin by placing the resin under a dynamic vacuum.

9. A process in accordance with claim 6 wherein said acid gas is desorbed from the anion exchange resin by purging with a humidified inert gas at ambient or slightly elevated temperature.