Removal of carbon dioxide from air

• US 8,133,305 B2
• Filed: 11/05/2008
• Issued: 03/13/2012
• Est. Priority Date: 11/05/2007
• Status: Active Grant

• Current Assignee: Carbon Sink, Inc.
• Original Assignee: Kilimanjaro Energy, Inc.
• Inventors: Lackner, Klaus S., Wright, Allen B.
• Primary Examiner(s): Chiesa, Richard L
• Application Number:
  US12/265,556
• Publication Number:
  US 20090120288A1
• Time in Patent Office: 1,224 Days
• Field of Search: 95/95, 95/96, 951/06, 95114-116, 951/39, 96143-146, 961/53, 423/230, 423/231, 422/122, 422/177, 422/178, 502/11, 502/414
• US Class Current: 95/139
• CPC Class Codes: B01D 2253/10 Inorganic adsorbents
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2253/206 Ion exchange resins
• CPC Class Codes: B01D 2257/304 Hydrogen sulfide
• CPC Class Codes: B01D 2257/406 Ammonia
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/0462 Temperature swing adsorption
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

The present invention provides a method and apparatus for removing a contaminant, such as carbon dioxide, from a gas stream, such as ambient air. The contaminant is removed from the gas stream by a sorbent which may be regenerated using a humidity swing, a thermal swing, or a combination thereof. The sorbent may be a substrate having embedded positive ions and individually mobile negative ions wherein the positive ions are sufficiently spaced to prevent interactions between the negative ions. Where a thermal swing is used, heat may be conserved by employing a heat exchanger to transfer heat from the regenerated sorbent to an amount of sorbent that is loaded with the contaminant prior to regeneration.

Claims

1. A method for removing carbon dioxide from a gas stream, comprising

placing said gas stream in contact with a substrate having a surface in which cations are physically embedded, wherein anions which are individually mobile are included on said surface, and wherein carbon dioxide from said gas stream becomes attached to said substrate by reacting with said anions;

and

releasing the carbon dioxide from said substrate to a contained environment by use of a humidity swing.

2. The method as recited in claim 1, wherein the cations that are embedded have a minimum spacing to prevent said anions from interacting with each other.

3. The method as recited in claim 1, wherein said anions are substrate is formed by ion implanting a cation material onto a neutral substrate material.

4. The method as recited in claim 3, wherein said cation material comprises a metal oxide or metal hydroxide.

5. The method as recited in claim 1, wherein said substrate is formed by sputtering an action material onto a neutral substrate material.

6. The method as recited in claim 1, wherein said substrate includes a zeolite material.

7. The method as recited in claim 1, wherein said substrate is formed of a non-electroactive material to which positive ions are added.

8. The method as recited in claim 1, wherein said substrate includes activated alumina as a material.

9. The method as recited in claim 1, wherein said substrate includes activated magnesia as a material.

10. The method as recited in claim 1, wherein said substrate includes activated iron oxide as a material.

11. A method of extracting CO₂ from a gas stream comprising exposing a sorbent to said gas stream so as to at least partially saturate said sorbent with CO₂, and releasing said captured CO₂ so as to regenerate said sorbent, wherein said sorbent comprises positive ions that are immobile and spaced such that carbonate ions are unstable in the presence of two single positive charges, and further wherein said sorbent is a metal oxide or metal hydroxide.

12. The method of claim 11, wherein said metal oxide or metal hydroxide is selected from the group consisting of:

aluminum hydroxide, magnesium hydroxide, iron(III) oxide, activated alumina, activated magnesia, and activated iron oxides.

13. The method of claim 11, wherein said gas stream is ambient air.

14. A method of extracting CO₂ from a gas stream comprising exposing a sorbent to said gas stream so as to at least partially saturate said sorbent with CO₂, and releasing said captured CO₂ so as to regenerate said sorbent, wherein said sorbent comprises positive ions that are immobile and spaced such that carbonate ions are unstable in the presence of two single positive charges, and further wherein said sorbent is a zeolite.

15. The method of claim 14, wherein said gas stream is ambient air.

16. The method of claim 14, wherein said zeolite releases captured CO₂ when exposed to a thermal swing, a water swing, a humidity swing, a voltage swing, or a thermal swing and a humidity swing.