CARBON DIOXIDE SORBENTS

• US 20110150730A1
• Filed: 12/20/2010
• Published: 06/23/2011
• Est. Priority Date: 12/22/2009
• Status: Active Grant

• Current Assignee: ExxonMobil Research & Engineering Company (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Research & Engineering Company (Exxon Mobil Corporation)
• Inventors: Berluche, Enock, Baugh, Lisa S., Li, Quanchang, Calabro, David C.
• Granted Patent: US 8,470,074 B2
• Time in Patent Office: Days
• US Class Current: 423/228
• CPC Class Codes: B01D 2252/20415 Tri- or polyamines
• CPC Class Codes: B01D 2252/20421 Primary amines
• CPC Class Codes: B01D 2252/20426 Secondary amines
• CPC Class Codes: B01D 2252/20431 Tertiary amines
• CPC Class Codes: B01D 2252/20436 Cyclic amines
• CPC Class Codes: B01D 2258/0283 Flue gases
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01D 53/1493 Selection of liquid materials for use as absorbents
• CPC Class Codes: B01J 20/103 comprising silica
• CPC Class Codes: B01J 20/265 modified or post-treated polymers polymer carriers or substrates subjected to further impregnating or coating B01J20/3208
• CPC Class Codes: B01J 20/2803 Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
• CPC Class Codes: B01J 20/2805 Sorbents inside a permeable or porous casing, e.g. inside a container, bag or membrane
• CPC Class Codes: B01J 20/28057 Surface area, e.g. B.E.T specific surface area
• CPC Class Codes: B01J 20/28083 being in the range 2-50 nm, i.e. mesopores
• CPC Class Codes: B01J 20/28097 being coated, filled or plugged with specific compounds
• CPC Class Codes: B01J 20/3204 Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/3272 Polymers obtained by reactions otherwise than involving only carbon to carbon unsaturated bonds
• CPC Class Codes: C08G 73/0206 Polyalkylene(poly)amines
• CPC Class Codes: C08G 73/0213 Preparatory process
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/151 : Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

Improved CO₂ sorbents comprised of a mesoporous silica functionalized with a polyamine are obtained by the in-situ polymerization of azetidine. Also included herein are processes utilizing the improved CO₂ sorbents wherein CO₂ is chemisorbed onto the polyamine portion of the sorbent and the process is thermally reversible.

Claims

1. A functionalized adsorbent material for adsorbing CO₂ from CO₂-containing gaseous streams, which adsorbent material comprises a mesoporous silica having at least a portion of its pores functionalized with in-situ polymerized cyclic amine in which the density of amine sites of the in-situ polymerized cyclic amine is below 20.0 mmol amine/gram.

2. The functionalized adsorbent material of claim 1 wherein the density of amine sites of the in-situ polymerized cyclic amine is from about 16.5 to about 19.0 mmol amine/gram.

3. The functionalized adsorbent material of claim 1 wherein the cyclic amine of the in-situ polymerized cyclic amine is azetidine and the resulting in-situ polymerized cyclic amine is poly(azetidine).

4. The functionalized adsorbent material of claim 1 wherein the in-situ polymerized cyclic amine has a branched structure and contains primary, secondary, and tertiary amine sites.

5. The functionalized adsorbent material of claim 4 wherein the ratios of primary:

secondary;

tertiary amines in the in-situ polymerized cyclic amine ranges from between about 2;

96;

2 to about 46;

8;

46.

6. The functionalized adsorbent material of claim 1 wherein the functionalized adsorbent material has a BET surface area from about 100 m²/g to about 1500 m²/g, and a pore volume from about 0.3 cc/g to about 1.8 cc/g.

7. The functionalized adsorbent material of claim 1 further comprising one or more additional components selected from the group consisting of amorphous silica binder, aluminum oxide binder, residual polymerization solvent, and residual polymerization initiator.

8. A method of preparing a functionalized adsorbent material comprised of a cyclic amine polymer for removing CO₂ from CO₂-containing gaseous streams, which method comprises:

forming a mixture comprised of a cyclic amine, a BrCnsted acid initiator in a solvent, and a mesoporous silica;

forming the cyclic amine polymer in the presence of the mesoporous silica; and

retrieving the resultant functionalized adsorbent material from the mixture as a solid;

wherein the resulting cyclic amine polymer has an amine density of below about 20.0 mmol amine/gram.

9. The method of claim 8 wherein the cyclic amine polymer has a density of amine sites from about 16.5 to about 19.0 mmol amine/gram.

10. The method of claim 8 wherein the cyclic amine is azetidine and the cyclic amine polymer is poly(azetidine).

11. The method of claim 8 wherein the BrCnsted acid initiator is selected from the group consisting of acetic acid and perchloric acid.

12. The method of claim 8 wherein the molar ratio of cyclic amine to Brø

nsted acid initiator is from about 8;

1 to about 30;

1.

13. The method of claim 8 wherein the mixture is at a temperature of from about 20°

C. to about 120°

C.

14. The method of claim 8 wherein the solvent is selected from the group consisting of toluene and methanol.

15. The method of claim 8 wherein the resultant functionalized adsorbent material has a BET surface area from about 100 m²/g to about 1500 m²/g, and a pore volume from about 0.3 cc/g to about 1.8 cc/g.

16. A method for removing CO₂ from a CO₂-containing gaseous stream, which method comprises contacting said stream with an effective amount of a functionalized adsorbent material comprising a mesoporous silica material having at least a portion of its pores functionalized with in-situ polymerized cyclic amine in which the density of amine sites of the in-situ polymerized cyclic amine is below 20.0 mmol amine/gram.

17. The method of claim 16 wherein the in-situ polymerized cyclic amine is poly(azetidine).

18. The method of claim 17 wherein the in-situ polymerized cyclic amine has a branched structure and contains primary, secondary, and tertiary amine sites.

19. The method of claim 18 wherein the ratios of primary:

secondary;

tertiary amines in the in-situ polymerized cyclic amine ranges from between about 2;

96;

2 to about 46;

8;

46.

20. The method of claim 16 wherein the functionalized adsorbent material has a BET surface area from about 100 m²/g to about 1500 m²/g, and a pore volume from about 0.3 cc/g to about 1.8 cc/g.

21. The method of claim 17 wherein the functionalized adsorbent material further comprises one or more additional components selected from the group consisting of amorphous silica binder, aluminum oxide binder, residual polymerization solvent, and residual polymerization initiator.

22. A method for removing CO₂ from a CO₂-containing gaseous stream, which method comprises contacting said gaseous stream with an effective amount of a liquid phase sorbent comprising an aqueous solution of a polymerized cyclic amine in which the density of amine sites of the polymerized cyclic amine is below about 20.0 mmol amine/gram.

23. The method of claim 22 wherein the polymerized cyclic amine is poly(azetidine).

24. The method of claim 23 wherein the poly(azetidine) has a branched structure and contains primary, secondary, and tertiary amine sites.

25. The method of claim 24 wherein the ratios of primary:

secondary;

tertiary amines in the polymerized cyclic amine ranges from between about 2;

96;

2 to about 46;

8;

46.

26. The method of claim 25 wherein the polymerized cyclic amine comprises from about 1% to about 30% of the total weight of the liquid phase sorbent.

27. The method of claim 26 wherein the contacting is performed at a temperature from about 15°

C. to about 120°

C.

28. The method of claim 27 wherein the liquid phase sorbent is comprised of water;

the chemisorption products comprise a mixture of carbamate, bicarbonate, and carbonate species; and

the chemisorption products maintain solubility in water.