Regenerable CO.sub.2 /H.sub.2 O solid sorbent

• US 5,091,358 A
• Filed: 06/27/1990
• Issued: 02/25/1992
• Est. Priority Date: 06/27/1990
• Status: Expired due to Fees

• Current Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Birbara, Philip J., Nalette, Timothy A.
• Primary Examiner(s): KONOPKA, PAUL
• Application Number:
  US07/544,716
• Time in Patent Office: 608 Days
• Field of Search: 502/400, 502/411, 502/412, 502/415, 502/174, 502/176, 502/243, 502/344, 502/347, 502/348
• US Class Current: 502/412
• CPC Class Codes: B01D 2253/1124 Metal oxides
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• 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: B01J 20/0233 Compounds of Cu, Ag, Au
• 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 20/06 comprising oxides or hydroxides of metals not provided for in group B01J20/04
• CPC Class Codes: B01J 20/14 Diatomaceous earth
• CPC Class Codes: B01J 20/3071 Washing or leaching
• CPC Class Codes: B01J 20/3085 Chemical treatments not covered by groups B01J20/3007 - B01J20/3078
• CPC Class Codes: B01J 20/3204 Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/3225 involving a post-treatment of the coated or impregnated product
• CPC Class Codes: B01J 20/3236 containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
• 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 2220/56 Use in the form of a bed
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

This invention relates to a CO₂ /H₂ O sorbent comprised of silver oxide, a CO₂ sorption promoter, and a support. Preparation of this sorbent consists of impregnating the support with a silver compound, converting the silver compound to silver carbonate or silver oxide, and further impregnating the support with a CO₂ sorption promoter. Prior to use as a sorbent, the silver carbonate is converted to silver oxide via the application of heat; liberating CO₂ and H₂ O.

Claims

1. A method for preparing a regenerable CO₂ /H₂ O sorbent, which comprises:

a. preparing an aqueous solution of a silver compound dissolved in a solvent;

b. impregnating a support with the aqueous solution of silver compound to form an impregnated support;

c. reacting the silver compound in the impregnated support with an alkali metal compound thereby converting said silver compound to an insoluble silver compound;

d. washing the impregnated support;

e. preparing an aqueous solution of a CO₂ sorption promoter dissolved in a solvent, wherein said CO₂ sorption promoter is an alkali metal salt having a pH of at least 11;

f. further impregnating the impregnated support with the aqueous solution of the CO₂ sorption promoter; and

g. drying said further impregnated support.

2. A method as in claim 1 wherein the silver compound is selected from the group consisting of silver nitrate, silver fluoride, silver dichromate, silver iodide, silver sulfate, and silver phosphate.

3. A method as in claim 1 wherein the insoluble silver compound is selected from the group consisting of silver carbonate and silver oxide.

4. A method as in claim 1 wherein said alkali metal compound is selected from the group consisting of carbonates and hydroxides of cesium, potassium, and sodium.

5. A method as in claim 1 wherein said CO₂ sorption promoter is selected from the group consisting of carbonates of cesium, potassium, and sodium.

6. A method as in claim 1 wherein the solvent is selected from the group consisting of water, and aqueous solutions of ammonium hydroxide, nitric acid, and sodium thiosulfate.

7. A method as in claim 1 wherein the support is selected from the group consisting of alumina, calcined diatomaceous earth, and magnesia.

16. A method as in claim 1 wherein said regenerable CO₂ /H₂ O sorbent has between about 6 wt% and about 40 wt% silver compound, about 30 wt% and about 70 wt% CO₂ sorption promoter, with the balance being the support.

8. A method for preparing a regenerable CO₂ /H₂ O sorbent, which comprises:

a. preparing an aqueous solution of a silver compound dissolved in a solvent, wherein the silver compound is selected from the group consisting of silver oxide and silver carbonate;

b. impregnating a support with the aqueous solution of the silver compound to form an impregnated support;

c. preparing an aqueous solution of a CO₂ sorption promoter dissolved in a solvent, wherein said CO₂ sorption promoter is an alkali metal salt having a pH of at least 11;

d. further impregnating the impregnated support with the aqueous solution of the CO₂ sorption promoter; and

e. drying said further impregnated support.

9. A method as in claim 8 wherein said CO₂ sorption promoter is selected from the group consisting of carbonates of cesium, potassium, and sodium.

10. A method as in claim 8 wherein the solvent is selected from the group consisting of aqueous solutions of ammonium hydroxide, nitric acid, and sodium thiosulfate.

11. A method as in claim 8 wherein the support is selected from the group consisting of alumina, calcined diatomaceous earth, and magnesia.

17. A method as in claim 8 wherein said regenerable CO₂ /H₂ O sorbent has between about 6 wt% and about 40 wt% silver compound, about 30 wt% and about 70 wt% CO₂ sorption promoter, with the balance being the support.

12. A CO₂ /H₂ O solid sorbent comprising a support impregnated with a CO₂ sorption promoter and an insoluble silver compound, which comprises between about 30 wt% to about 70 wt% CO₂ sorption promoter, about 6 wt% to about 40 wt% silver compound, with the balance being the support, wherein said CO₂ sorption promoter is an alkali metal salt having a pH of at least 11.

13. A CO₂ /H₂ O solid sorbent as in claim 12 wherein the support is selected from the group consisting of alumina, calcined diatomaceous earth, and magnesia.

14. A CO₂ /H₂ O solid sorbent as in claim 12 wherein said CO₂ sorption promoter is selected from the group consisting of carbonates of cesium, potassium, and sodium.

15. A CO₂ /H₂ O solid sorbent as in claim 12 wherein said insoluble silver compound is selected from the group consisting of silver carbonate and silver oxide.