MIXED SALT CO2 SORBENT, PROCESS FOR MAKING AND USES THEREOF

• US 20130195742A1
• Filed: 01/18/2013
• Published: 08/01/2013
• Est. Priority Date: 01/20/2012
• Status: Active Grant

• Current Assignee: Saudi Arabian Oil Company (Government of Saudi Arabia), Research Triangle Institute
• Original Assignee: Research Triangle Institute
• Inventors: HAMAD, Esam Zaki, AL-SADAT, Wajdi Issam, COLEMAN, Luke, SHEN, J.P., GUPTA, Raghubir
• Granted Patent: US 9,539,541 B2
• Time in Patent Office: Days
• US Class Current: 423/213.2
• CPC Class Codes: B01D 2251/30 Alkali metal compounds
• CPC Class Codes: B01D 2251/302 of lithium
• CPC Class Codes: B01D 2251/304 of sodium
• CPC Class Codes: B01D 2251/306 of potassium
• CPC Class Codes: B01D 2251/402 of magnesium
• CPC Class Codes: B01D 2251/60 Inorganic bases or salts
• CPC Class Codes: B01D 2251/602 Oxides
• CPC Class Codes: B01D 2251/606 Carbonates
• CPC Class Codes: B01D 2253/112 Metals or metal compounds not provided for in B01D2253/104 or B01D2253/106
• CPC Class Codes: B01D 2253/1124 Metal oxides
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2258/012 Diesel engines and lean burn gasoline engines
• CPC Class Codes: B01D 2259/4566 for use in transportation means
• 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 53/62 Carbon oxides
• CPC Class Codes: B01D 53/82 with stationary reactants
• CPC Class Codes: B01D 53/92 of engine exhaust gases exhaust or silencing apparatus for internal combustion engines, machines or engines in general, having means for purifying, rendering innocuous or otherwise treating exhaust gases F01N3/00
• CPC Class Codes: B01D 53/94 by catalytic processes
• CPC Class Codes: B01J 20/04 comprising compounds of alkali metals, alkaline earth metals or magnesium
• CPC Class Codes: B01J 20/041 Oxides or hydroxides
• CPC Class Codes: B01J 20/043 : Carbonates or bicarbonates, e.g. limestone, dolomite, aragonite
• CPC Class Codes: B01J 20/3085 : Chemical treatments not covered by groups B01J20/3007 - B01J20/3078
• CPC Class Codes: B01J 20/3433 : of sorbents or filter aids other than those covered by B01J20/3408 - B01J20/3425
• 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 2220/42 : Materials comprising a mixture of inorganic materials materials coated or impregnated on a carrier B01J20/32
• CPC Class Codes: Y02A 50/20 : Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/40 : of CO2

Abstract

The invention relates to a mixed salt composition which is useful as a CO₂ sorbent. The mixed salt composition comprises a Mg salt, and at least one Group IA element salt, where the Mg and Group IA element are present at a molar ratio of from 3:1 to 8:1. The resulting composition can adsorb about 20% or more of CO2 in a gas. Via varying the molar ratios of the components, and the Group IA element, one can develop compositions which show optional functionality at different conditions. The composition is especially useful in the adsorptive capture of CO₂ on mobile sources, such as transportation vehicles, where it can be recovered during regeneration of the adsorbent composition and the CO₂ used as a coolant gas, as a reactant in manufacture of fuel, and so forth.

Claims

1. A mixed salt composition useful as a sorbent for CO₂, comprising:

(i) a magnesium salt, and

(ii) at least one salt of a Group IA element wherein (i) said magnesium salt and (ii) said Group IA element salt are present in a molar ratio of from about 8;

1-3;

1.

2. The mixed salt composition of claim 1, wherein (i) and (ii) are present in a ratio of from 6:

1-4;

1.

3. The mixed salt composition of claim 1, wherein (i) is MgCO₃ or MgO.

4. The mixed salt composition of claim 3, wherein (i) is MgO.

5. The mixed salt composition of claim 1, wherein (ii) is a carbonate or a nitrate.

6. The mixed salt composition of claim 1, wherein (ii) is a Na, Li, K, or Rb salt.

7. The mixed salt composition of claim 1, wherein salt composition further comprises a sodium salt.

8. The mixed salt composition of claim 1, wherein (i) is Na₂CO₃ or NaNO₃.

9. The mixed salt composition of claim 1, of formula MgO:

Na₂CO₃;

NaNO₃.

10. A process for making the mixed salt composition of claim 1, comprising combining solutions of (i) a magnesium salt and (ii) a Group IA element salt to form a reaction mixture, under conditions favoring forming a precipitation product therefrom.

11. The process of claim 10, further comprising adding a precipitating agent.

12. The process of claim 10, wherein (i) is a solution of MgO, Mg(OH)₂, Mg(NO₃)₂, MgCl₂, or Mg(CH₃COO)₂.

13. The process of claim 10, wherein (i) is a solution of Mg(NO₃)₂.

14. The process of claim 10, wherein (i) and (ii) are selected so as to form MgO or MgCO₃ therefrom.

15. A method for removing CO₂ from a gas or gas mixture, comprising contacting the mixed salt composition of claim 1 with said gas or gas mixture at a temperature of from about 100°

C. to about 450°

C., for a time sufficient for said mixed salt composition to remove a portion of CO₂ therefrom.

16. The method of claim 15, wherein said temperature is from about 250°

C. to about 350°

C.

17. The method of claim 15, further comprising contacting said mixed salt composition with an inert gas to removed any CO₂ adsorbed therein.

18. The method of claim 17, wherein said inert gas is N₂.

19. The method of claim 17, comprising contacting said inert gas to said mixed salt composition at a temperature of about 500°

C.

20. The method of claim 15, further comprising placing said mixed salt composition on a mobile source and effecting adsorption of CO₂ from an internal combustion engine'"'"'s exhaust gas stream produced via combustion of hydrocarbon fuel on said mobile source.

21. The method of claim 20, comprising releasing the adsorbed CO₂ to regenerate the composition by heat exchange with the hot exhaust gas stream discharged from the engine.

22. The method of claim 20, wherein said mobile source is a transportation vehicle.

23. The method of claim 21, wherein said transportation vehicle is an automobile, truck, bus, train, or boat, and the fuel is gasoline or diesel fuel.