ULTRA CLEANING OF COMBUSTION GAS INCLUDING THE REMOVAL OF CO2

• US 20100064889A1
• Filed: 11/20/2009
• Published: 03/18/2010
• Est. Priority Date: 08/06/2004
• Status: Active Grant

• Current Assignee: General Electric Technology GmbH (GE Aerospace)
• Original Assignee: EIG, Inc.
• Inventors: Gal, Eli
• Granted Patent: US 8,308,849 B2
• Time in Patent Office: Days
• US Class Current: 95/183
• CPC Class Codes: B01D 2251/2062 Ammonia
• CPC Class Codes: B01D 2252/102 Ammonia
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01D 53/75 Multi-step processes
• CPC Class Codes: F23J 15/006 Layout of treatment plant
• CPC Class Codes: F23J 15/06 of coolers
• CPC Class Codes: F23J 2215/50 Carbon dioxide
• CPC Class Codes: F23J 2219/50 Sorption with semi-dry devices, e.g. with slurries
• 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
• CPC Class Codes: Y02E 20/32 Direct CO2 mitigation

Abstract

Ultra cleaning of combustion gas to near zero concentration of residual contaminants followed by the capture of CO₂ is provided. The high removal efficiency of residual contaminants is accomplished by direct contact cooling and scrubbing of the gas with cold water. The temperature of the combustion gas is reduced to 0-20 degrees Celsius to achieve maximum condensation and gas cleaning effect. The CO₂ is captured from the cooled and clean flue gas in a CO₂ absorber utilizing an ammoniated solution or slurry in the NH₃—CO₂—H₂O system. The absorber operates at 0-20 degrees Celsius. Regeneration is accomplished by elevating the pressure and temperature of the CO₂-rich solution from the absorber. The CO₂ vapor pressure is high and a pressurized CO₂ stream, with low concentration of NH₃ and water vapor is generated. The high pressure CO₂ stream is cooled and washed to recover the ammonia and moisture from the gas.

Claims

1-32. -32. (canceled)

33. A method for removing CO₂ from a combustion gas stream, comprising:

cooling the gas stream to a first temperature in the range of 0-20 degrees Celsius;

cooling an ammoniated solution or slurry to a second temperature in the range of 0-20 degrees Celsius;

absorbing CO₂ from the cooled gas stream using the cooled ammoniated solution or slurry to provide a CO₂ rich ammoniated solution or slurry;

pressurizing the CO₂ rich ammoniated solution or slurry to a first pressure in the range of 30-2000 psi; and

heating the pressurized CO₂ rich ammoniated solution or slurry to a third temperature in the range of 50-200 degrees Celsius to separate CO₂ from the pressurized ammoniated solution or slurry, wherein the first pressure and third temperature are selected to prevent ammonia from escaping the liquid phase during the separation of CO₂ from the pressurized ammoniated solution or slurry and the separated CO₂ is in a form of a pressurized gas in the range of the first pressure.

34. The method of claim 33, wherein the first temperature is in the range of 0-10 degrees Celsius.

35. The method of claim 33, wherein the second temperature is in the range of 0-10 degrees Celsius.

36. The method of claim 33, wherein the first and second temperatures are in the range of 0-10 degrees Celsius.

37. The method of claim 33, wherein the ammoniated solution or slurry used to absorb the CO₂ is a CO₂ lean solution or slurry containing NH3, CO2 and H2O or their aqueous species.

38. The method of claim 37, wherein the CO₂-lean solution or slurry has a NH₃/CO₂ mole ratio in the range of 1.5-4.0.

39. The method of claim 37, wherein the species in the NH₃—

CO₂—

H₂O solution or slurry are concentrated such to contain dissolved species and suspended solids in the form of ammonium bicarbonate, NH₄HCO₃, crystals.

40. The method of claim 33, wherein the ammoniated solution or slurry with the absorbed CO₂ is a CO₂-rich solution having a NH₃/CO₂ mole ratio in the range of 1.0-2.0.

41. The method as of claim 33, wherein the first pressure is in the range of 150-400 psi.

42. The method of claim 33, wherein the third temperature is in the range of 100 to 150 degrees Celsius.

43. The method of claim 33, further comprising:

washing residual ammonia from the cooled gas stream using water after absorbing CO₂ from the cooled gas stream.

44. The method of claim 43, further comprising:

washing residual ammonia from the cooled gas stream using an acidic solution after absorbing CO₂ from the cooled gas stream and after washing the cooled gas stream with water.

45. The method of claim 33, further comprising:

washing residual ammonia from the cooled gas stream using an acidic solution after absorbing CO₂ from the cooled gas stream.

46. The method of claim 33, wherein cooling the gas stream to the first temperature is performed by wet and direct cooling.

47. The method of claim 33, wherein cooling the gas stream to the first temperature is performed in a series of cooling stages.

48. The method of claim 47, wherein at least one cooling stage in the series of cooling stages includes a direct contact cooler.

49. The method of claim 33, wherein absorbing CO₂ from the cooled gas stream using the cooled ammoniated solution or slurry is performed in a series of absorber stages.

50. A method for removing CO2 from a combustion gas stream, comprising:

cooling the gas stream to a first temperature in the range of 0-20 degrees Celsius in a series of cooling stages;

cooling an ammoniated solution or slurry to a second temperature in the range of 0-20 degrees Celsius;

applying the cooled ammoniated solution or slurry to the gas stream in a series of absorbing stages to absorb CO₂ from the cooled gas stream and provide a CO₂ rich ammoniated solution or slurry;

pressurizing the CO₂ rich ammoniated solution or slurry to a first pressure in the range of 30-2000 psi; and

heating the pressurized CO₂ rich ammoniated solution or slurry to a third temperature in the range of 50-200 degrees Celsius to separate CO₂ from the pressurized ammoniated solution or slurry, wherein the first pressure and third temperature are selected to prevent ammonia from escaping the liquid phase during the separation of CO₂ from the pressurized ammoniated solution or slurry and the separated CO2 is in a form of a pressurized gas.

51. The method of claim 50, further comprising:

washing residual ammonia from the cooled gas stream using an acidic solution after absorbing CO₂ from the cooled gas stream.

52. A system for removing CO2 from a combustion gas stream, comprising:

means for cooling the gas stream to a first temperature in the range of 0-20 degrees Celsius;

means for cooling an ammoniated solution or slurry to a second temperature in the range of 0-20 degrees Celsius;

means for absorbing CO₂ from the cooled gas stream using the cooled ammoniated solution or slurry to provide a CO₂ rich ammoniated solution or slurry;

means for pressurizing the CO₂ rich ammoniated solution or slurry to a first pressure in the range of 30-2000 psi; and

means for heating the pressurized CO₂ rich ammoniated solution or slurry to a third temperature in the range of 50-200 degrees Celsius to separate CO₂ from the pressurized ammoniated solution or slurry, wherein the first pressure and third temperature are selected to prevent ammonia from escaping the liquid phase during the separation of CO₂ from the pressurized ammoniated solution or slurry and the separated CO2 is in a form of a pressurized gas.