Separation of carbon dioxide from gas mixtures by calcium based reaction separation

• US 8,226,917 B2
• Filed: 06/28/2006
• Issued: 07/24/2012
• Est. Priority Date: 02/06/2003
• Status: Active Grant

• Current Assignee: Ohio State University
• Original Assignee: Ohio State University
• Inventors: Fan, Liang-Shih, Gupta, Himanshu, Iyer, Mahesh V.
• Primary Examiner(s): Johnson, Edward
• Application Number:
  US11/994,316
• Publication Number:
  US 20080233029A1
• Time in Patent Office: 2,218 Days
• Field of Search: 423220-225, 423/244.01, 423/244.02, 423/244.03, 423/244.06, 423/244.08, 423/244.1
• US Class Current: 423/244.03
• CPC Class Codes: B01D 2251/404 of calcium
• CPC Class Codes: B01D 2253/10 Inorganic adsorbents
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• 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: B01D 53/508 by treating the gases with solids
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01J 20/041 Oxides or hydroxides
• CPC Class Codes: B01J 20/06 comprising oxides or hydroxides of metals not provided for in group B01J20/04
• CPC Class Codes: B01J 20/28057 Surface area, e.g. B.E.T specific surface area
• CPC Class Codes: B01J 20/28071 being less than 0.5 ml/g
• 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 20/3466 with steam
• 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 8/06 in tube reactors; the solid particles being arranged in tubes
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01F 11/06 of carbonates
• CPC Class Codes: C01P 2002/32 spinel-type (AB2O4)
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2006/12 : Surface area
• CPC Class Codes: C01P 2006/14 : Pore volume
• CPC Class Codes: C01P 2006/17 : Pore diameter distribution
• CPC Class Codes: C10J 2300/0996 : Calcium-containing inorganic materials, e.g. lime
• CPC Class Codes: C10J 2300/1807 : Recycle loops, e.g. gas, solids, heating medium, water
• CPC Class Codes: C10J 3/482 : Gasifiers with stationary fluidised bed
• CPC Class Codes: C10K 1/024 : by filtration
• CPC Class Codes: C10K 3/04 : reducing the carbon monoxide content , e.g. water-gas shift [WGS]
• CPC Class Codes: H01M 2008/1293 : Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 8/0668 : Removal of carbon monoxide or carbon dioxide
• CPC Class Codes: Y02C 20/40 : of CO2
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 20/151 : Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

A reaction-based process has been developed for the selective removal of carbon dioxide (CO₂) from a multicomponent gas mixture to provide a gaseous stream depleted in CO2 compared to the inlet CO₂ concentration in the stream. The proposed process effects the separation of CO₂ from a mixture of gases (such as flue gas/fuel gas) by its reaction with metal oxides (such as calcium oxide). The Calcium based Reaction Separation for CO₂ (CaRS—CO₂) process consists of contacting a CO₂ laden gas with calcium oxide (CaO) in a reactor such that CaO captures the CO₂ by the formation of calcium carbonate (CaCOa). Once “spent”, CaCO₃ is regenerated by its calcination leading to the formation of fresh CaO sorbent and the evolution of a concentrated stream of CO₂. The “regenerated” CaO is then recycled for the further capture of more CO₂. This carbonation-calcination cycle forms the basis of the CaRS—CO₂ process. This process also identifies the application of a mesoporous CaCO₃ structure, developed by a process detailed elsewhere, that attains >90% conversion over multiple carbonation and calcination cycles. Lastly, thermal regeneration (calcination) under vacuum provided a better sorbent structure that maintained reproducible reactivity levels over multiple cycles.

Claims

1. A method for separating carbon dioxide and sulfur dioxide from a flow of gas comprising carbon dioxide and sulfur dioxide, said method comprising the steps of:

(a) directing said flow of gas to a gas-solid contact reactor, said gas-solid contact reactor containing a sorbent comprising a metal oxide;

(b) reacting said carbon dioxide and said sulfur dioxide with said sorbent so as to convert at least a portion of said sorbent to a metal carbonate and at least a portion of said sorbent to a metal sulfate;

(c) directing at least a portion of said metal carbonate to a calcinator;

(d) calcining said metal carbonate so as to form said metal oxide and carbon dioxide; and

(e) replenishing said sorbent in said gas-solid reactor with said metal oxide formed in said calcinator.

2. The method according to claim 1, additionally comprising the step of:

separating said metal carbonate from said flow of gas in a cyclone.

3. The method according to claim 1, wherein said step of reacting said carbon dioxide and said sulfur dioxide with said sorbent occurs at a temperature in the range of from about 600 to about 650 degrees Celsius.

4. The method according to claim 1, additionally comprising the step of:

sequestering said carbon dioxide formed in said calcinator.

5. The method according to claim 1, wherein said metal oxide is calcium oxide that has a surface area of less than 22 m2/g, a pore volume of at least 0.005 cm3/g, and a mesoporous pore size distribution.

6. The method according to claim 1, wherein said step of calcining said metal carbonate is conducted under at least partial vacuum.

7. The method according to claim 1, wherein said step of calcining said metal carbonate is performed by steam.

8. The method according to claim 1, wherein said metal oxide is selected from the group consisting of:

ZnO, MgO, MnO2, NiO, CuO, PbO, and CaO.

9. The method according to claim 1, wherein said sorbent has a sorption capacity of at least about 70 grams of carbon dioxide per kilogram of sorbent.

10. The method according to claim 1, wherein said sorbent has a sorption capacity of at least about 300 grams of carbon dioxide per kilogram of sorbent.

11. The method according to claim 1, wherein said sorbent has substantially the same sorption capacity after calcining as said sorbent had prior to absorbing said carbon dioxide.

12. The method according to claim 1, wherein said step of calcining said metal carbonate occurs at a temperature in the range of from about 800 to about 850 degrees Celsius.

13. A facility practicing the method according to claim 1.