Nano-structure supported solid regenerative polyamine and polyamine polyol absorbents for the separation of carbon dioxide from gas mixtures including the air

• US 7,795,175 B2
• Filed: 07/19/2007
• Issued: 09/14/2010
• Est. Priority Date: 08/10/2006
• Status: Active Grant

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Goepert, Alain, Meth, Sergio, Olah, George A., Prakash, G. K. Surya
• Primary Examiner(s): Johnson; Edward M
• Application Number:
  US11/780,244
• Publication Number:
  US 20080293976A1
• Time in Patent Office: 1,153 Days
• Field of Search: 502/400, 502/401
• US Class Current: 502/401
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/025 with wetted adsorbents; Chromatography analytical chromatography G01N30/00 - G01N30/96; for liquids B01D15/08
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01J 20/103 comprising silica
• CPC Class Codes: B01J 20/28007 with size in the range 1-100 nanometers, e.g. nanosized particles, nanofibers, nanotubes, nanowires or the like carbon nanostructures B01J20/205
• CPC Class Codes: B01J 20/28061 being in the range 100-500 m2/g
• CPC Class Codes: B01J 20/3021 Milling, crushing or grinding
• CPC Class Codes: B01J 20/3204 Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/3251 comprising at least two different types of heteroatoms selected from nitrogen, oxygen or sulphur
• CPC Class Codes: B01J 20/3253 comprising a cyclic structure not containing any of the heteroatoms nitrogen, oxygen or sulfur, e.g. aromatic structures
• CPC Class Codes: B01J 20/3272 Polymers obtained by reactions otherwise than involving only carbon to carbon unsaturated bonds
• CPC Class Codes: B01J 20/3425 of sorbents or filter aids comprising organic materials
• CPC Class Codes: B01J 20/3483 by thermal treatment not covered by groups B01J20/3441 - B01J20/3475, e.g. by heating or cooling
• CPC Class Codes: B01J 20/3491 by pressure treatment
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C07C 1/20 starting from organic compounds containing only oxygen atoms as heteroatoms
• CPC Class Codes: C07C 11/02 Alkenes
• CPC Class Codes: C07C 29/04 by hydration of carbon-to-carbon double bonds
• CPC Class Codes: C07C 29/149 with hydrogen or hydrogen-containing gases
• CPC Class Codes: C07C 31/04 Methanol
• CPC Class Codes: C07C 31/08 : Ethanol
• CPC Class Codes: C07C 31/10 : containing three carbon atoms
• CPC Class Codes: C07C 41/09 : by dehydration of compounds containing hydroxy groups
• CPC Class Codes: C07C 43/043 : Dimethyl ether
• CPC Class Codes: Y02C 20/40 : of CO2
• CPC Class Codes: Y02P 20/151 : Reduction of greenhouse gas [GHG] emissions, e.g. CO2
• CPC Class Codes: Y02P 20/50 : Improvements relating to the production of bulk chemicals

Abstract

The invention relates to regenerative, supported amine sorbents that includes an amine or an amine/polyol composition deposited on a nano-structured support such as nanosilica. The sorbent provides structural integrity, as well as high selectivity and increased capacity for efficiently capturing carbon dioxide from gas mixtures, including the air. The sorbent is regenerative, and can be used through multiple operations of absorption-desorption cycles.

Claims

1. A solid carbon dioxide sorbent for absorbing carbon dioxide from a gas mixture and which is capable of releasing the absorbed carbon dioxide when treated for regeneration, the sorbent comprising an amine in an amount of at least 25% by weight of the sorbent and nano-sized solid particles having a primary particle size that is less than about 100 nm for providing structural integrity and support for the amine and a high surface area for amine-gas contact.

2. The sorbent according to claim 1, wherein the nano-structured support is a nanosilica, silica-alumina and the like fumed or precipitated oxide, calcium silicate, carbon nanotube, or mixture thereof.

3. The sorbent according to claim 1, wherein the amine is a primary, secondary, or tertiary amine or alkanolamine, aromatic amine, or mixtures or combinations thereof.

4. The sorbent according to claim 1, wherein the amine is monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine, 2-(2-aminoethylamino)-ethanol, diisopropanolamine, 2-amino-2-methyl-1,3-propanediol, triethanolamine, tetraethylenepentamine, pentaethylenehexamine, or polyethyleneimine.

5. The sorbent according to claim 4, wherein the amine is a linear or branched polyethyleneimine having a molecular weight greater than 600.

6. The sorbent according to claim 1, in which the amine is present in an amount of about 25% to 75% by weight of the sorbent.

7. The sorbent according to claim 1, which further comprises a polyol in an amount up to about 25% by weight of the sorbent.

8. The sorbent according to claim 7, wherein the polyol is selected from the group consisting of glycerol, oligomers of ethylene glycol, polyethylene glycol, polyethylene oxides, and ethers, modifications and mixtures thereof.

9. The sorbent according to claim 1, wherein the nano-sized particles are nanosilica, the amine is polyethyleneimine in an amount of about 25% to 75% by weight of the sorbent, and the sorbent further comprises polyethylene glycol in an amount up to 25% by weight of the sorbent.

10. The sorbent according to claim 1, which releases absorbed carbon dioxide when treated for regeneration.

11. The sorbent according to claim 10, wherein the sorbent is treated with sufficient heat, reduced pressure, vacuum, gas purge, or a combination thereof to release a substantial amount or all the absorbed carbon dioxide.

12. A method for preparing the sorbent of claim 1, which comprises dispersing the nano-sized particles in a solvent to form a suspension;

dissolving the amine in the solvent to form an amine solution;

combining the suspension and the amine solution; and

removing the solvent to form the sorbent.

13. The method according to claim 12, which further comprises adding a polyol in the amine solution or the suspension before combining the solution and the suspension.

14. The method according to claim 12, which further comprises adding a polyol to the suspension;

drying the suspension after the addition of the polyol to form a supported polyol;

dispersing the supported polyol in the solvent; and

combining the dispersed supported polyol and the amine solution prior to removing the solvent to form the sorbent.

15. A method for continuously capturing and separating carbon dioxide from a gas mixture with a sorbent, which comprises exposing the sorbent according to claim 1 to the gas mixture to effect absorption of carbon dioxide by the sorbent and treating the sorbent that contains absorbed or entrapped carbon dioxide to release a substantial amount or all the absorbed carbon dioxide.

16. The method according to claim 15, wherein the sorbent is provided in a fixed, moving, or fluidized bed and the gas and bed are in contact for a sufficient time to trap the carbon dioxide in the sorbent.

17. The method according to claim 15, wherein the sorbent is treated with sufficient heat, reduced pressure, vacuum, gas purge, or a combination thereof to release the absorbed carbon dioxide.

18. The method according to claim 17, wherein the sorbent is treated when up to 90% of the amine is complexed with carbon dioxide.

19. The method according to claim 15, which further comprises reacting the released carbon dioxide to form useful products.

20. The method according to claim 19, wherein carbon dioxide is used to produce methanol by (a) electrochemical reduction of carbon dioxide in water or (b) reducing carbon dioxide under conditions sufficient to produce an intermediate compound and catalytically hydrogenating the intermediate compound with hydrogen under conditions sufficient to form methanol.

21. The method according to claim 20, wherein the intermediate compound is methyl formate.

22. The method according to claim 19, which further comprises reducing the carbon dioxide under conditions sufficient to carbon monoxide, reacting the carbon monoxide with methanol under conditions sufficient to obtain methyl formate, and catalytically hydrogenating the methyl formate under conditions sufficient to produce methanol.

23. The method according to claim 19, which further comprises dehydrating the methanol under conditions sufficient to produce dimethyl ether.

24. The method according to claim 23, which further comprises heating the dimethyl ether in the presence of an acidic-basic or zeolitic catalyst under conditions sufficient to form ethylene and/or propylene.

25. The method according to claim 24, which further comprises converting the ethylene and/or propylene under conditions sufficient to higher olefins, a synthetic hydrocarbons, aromatics, or a product produced therefrom, for use as a feedstock for chemicals or as transportation fuel.

26. The method according to claim 24, which further comprises hydrating the ethylene or propylene under conditions sufficient to form ethanol or propanol.