Separation of carbon dioxide (CO2) from gas mixtures by calcium based reaction separation (CaRS-CO2) process

• US 20060039853A1
• Filed: 02/06/2003
• Published: 02/23/2006
• Est. Priority Date: 02/06/2003
• Status: Active Grant

• Current Assignee: The Ohio State University Research Foundation
• Original Assignee: The Ohio State University Research Foundation
• Inventors: Gupta, Himanshu, Fan, Liang-Shih
• Granted Patent: US 7,067,456 B2
• Time in Patent Office: Days
• US Class Current: 423/637
• CPC Class Codes: B01D 2251/402 of magnesium
• CPC Class Codes: B01D 2251/404 of calcium
• CPC Class Codes: B01D 53/62 Carbon oxides
• 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 20/28057 Surface area, e.g. B.E.T specific surface area
• CPC Class Codes: B01J 20/28069 Pore volume, e.g. total pore volume, mesopore volume, micropore volume
• CPC Class Codes: B01J 20/28088 Pore-size distribution
• 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: C01F 11/06 of carbonates
• 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: C04B 2/10 Preheating, burning calcining or cooling decarbonation during burning of cement raw materials C04B7/43; obtaining CaO or MgO otherwise than by thermal decomposition of the corresponding carbonates C01F11/02, C01F5/02
• 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 40/40 Production or processing of lime, e.g. limestone regeneration of lime in pulp and sugar mills

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 (CaCO₃). 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

1-26. -26. (canceled)

27. A method for producing a sorbent, said method comprising the steps of:

obtaining a structurally altered high surface area calcium carbonate having a surface area of at least 25.0 m²/g, a pore volume of at least 0.05 cm³/g, and a mesoporous pore size distribution; and

calcining said structurally altered high surface area calcium carbonate so as to produce a sorbent having 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.

28. The method according to claim 27 wherein said calcining is conducted under at least partial vacuum.

29. The method according to claim 27 wherein said calcining is conducted by steam.

30. (canceled)

31. (canceled)