Process for removing carbon dioxide from combustion gases

• US 6,689,332 B1
• Filed: 02/20/1996
• Issued: 02/10/2004
• Est. Priority Date: 09/16/1992
• Status: Expired due to Fees

• Current Assignee: Kansai Electric Power Company Incorporated, Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Kansai Electric Power Company Incorporated, Mitsubishi Jukogyo Kabushiki Kaisha (Mitsubishi Heavy Industries, Ltd.)
• Inventors: Karasaki, Mutsunori, Mitsuoka, Shigeaki, Shimojo, Shigeru, Iijima, Masaki, Mimura, Tomio, Yoshida, Kunihiko
• Primary Examiner(s): Silverman, Stanley S.
• Assistant Examiner(s): Vanoy, Timothy C.
• Application Number:
  US08/603,186
• Time in Patent Office: 2,912 Days
• Field of Search: 423/220, 423/228, 423/229, 252/387, 106/14.05
• US Class Current: 423/220
• 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: 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

A process for removing CO₂ from a combustion gas which comprises bringing a combustion gas containing oxygen and CO₂ and a CO₂ absorbent solution into contact at the atmospheric pressure, thereby allowing the CO₂ absorbent solution to absorb CO₂ from the combustion gas, and, in the ensuing step, heating the absorbent solution that has absorbed CO₂ to liberate CO₂ and regenerate the CO₂ absorbent solution, and circulating the regenerated solution for reuse. An aqueous solution of a hindered amine selected from the group consisting of 2-amino-2-methyl-1-propanol (AMP), 2-(ethylamino)-ethanol (EAE), 2-(methylamino)-ethanol (MAE), and 2-(diethylamino)-ethanol (DEAE) is used as the CO₂ absorbent solution, and carbon steel is used in building the members of the equipment that contact the aqueous hindered amine solution. The absorbent solution contains cupric carbonate which is a corrosion inhibitor.

Claims

1. A process for removing carbon dioxide from a combustion gas which comprises:

in an apparatus made from carbon steel, bringing a combustion gas which contains oxygen gas and carbon dioxide into contact with an aqueous solution of a hindered amine selected from the group consisting of 2-amino-2-methyl-1-propanol (AMP), 2-(ethylamino)-ethanol (EAE), 2-(methylamino)-ethanol (MAE), and 2-(diethylamino)-ethanol (DEAE) containing cupric carbonate, at the atmospheric pressure,

allowing the aqueous solution to absorb carbon dioxide from the combustion gas, and, in the ensuing step,

heating the aqueous solution that has absorbed carbon dioxide, to liberate carbon dioxide and regenerate the aqueous solution, and

circulating the regenerated solution for reuse.

2. The process as claimed in claim 1, wherein the hindered amine is 2-amino-2-methyl-1-propanol.

3. The process as claimed in claim 1, wherein the hindered amine is 2-(methylamino)-ethanol.

4. The process as claimed in claim 1, wherein the hindered amine is 2-(diethylamino)-ethanol.

5. The method according to claim 1, wherein the concentration of the aqueous hindered amine solution used as the carbon dioxide absorbent solution is 25-65%.

6. The process of claim 1, wherein the aqueous solution is 30 wt % of the hindered amine.

7. A process for reducing the corrosion rate of carbon steel from an aqueous solution of a hindered amine selected from the group consisting of 2-amino-2-methyl-1-propanol (AMP), 2-(ethylamino)-ethanol (EAE), 2-(methylamino)-ethanol (MAE), and 2-(diethylamino)-ethanol (DEAE) containing cupric carbonate employed in a process for removing carbon dioxide from a combustion gas which comprises:

in an apparatus made from carbon steel, bringing the combustion gas containing oxygen gas and carbon dioxide into contact with the aqueous solution at the atmospheric pressure,

allowing the aqueous solution to absorb carbon dioxide from the combustion gas, and, in the ensuing step,

heating the aqueous solution that has absorbed carbon dioxide, to liberate carbon dioxide and regenerate the aqueous solution, and

circulating the regenerated solution for reuse.

8. The process as claimed in claim 7, wherein the hindered amine is 2-amino-2-methyl-1-propanol.

9. The process as claimed in claim 7, wherein the hindered amine is 2-(methylamino)-ethanol.

10. The process as claimed in claim 7, wherein the hindered amine is 2-(diethylamino)-ethanol.

11. The method according to claim 7, wherein the concentration of the aqueous hindered amine solution used as the carbon dioxide absorbent solution is 25-65%.

12. The process of claim 7, wherein the aqueous solution is 30 wt % of the hindered amine.