CO;recovery system and CO;recovery method

• US 8,974,582 B2
• Filed: 02/13/2013
• Issued: 03/10/2015
• Est. Priority Date: 12/25/2009
• Status: Active Grant

• Current Assignee: Kansai Electric Power Company Incorporated, Mitsubishi Heavy Industries Engineering, Ltd. (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Kansai Electric Power Company Incorporated, Mitsubishi Heavy Industries, Ltd.
• Inventors: Nagayasu, Hiromitsu, Kamijo, Takashi, Yonekawa, Takahito, Tanaka, Hiroshi, Kishimoto, Shinya, Hirata, Takuya, Tsujiuchi, Tatsuya, Chiyomaru, Masaru, Nakayama, Koji, Tatsumi, Masahiko, Yagi, Yasuyuki, Kaibara, Kazuhiko
• Primary Examiner(s): LAWRENCE JR, FRANK M
• Application Number:
  US13/766,082
• Publication Number:
  US 20130164203A1
• Time in Patent Office: 755 Days
• Field of Search: 962/34, 962/43, 962/67, 951/49, 951/87, 951/88, 951/93, 951/99, 952/06, 952/09, 952/36, 423/220, 423/228, 423/229, 422169-171
• US Class Current: 96/188
• CPC Class Codes: B01D 2252/204 Amines
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/1418 Recovery of products
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A CO₂ recovery system includes an absorber 2 and a regenerator 3. The absorber 2 includes a CO₂ absorbing section 21 and a water-washing section 22. The CO₂ absorbing section 21 allows flue gas 101 to come into contact with a basic amine compound absorbent 103 so that the basic amine compound absorbent 103 absorbs CO₂ in the flue gas 101. The water-washing section 22 allows the decarbonated flue gas 101A in which the amount of CO₂ has been reduced in the CO₂ absorbing section 21 to come into contact with circulating wash water 104 and to be washed with the wash water 104 so that the amounts of the basic amine compounds entrained in the decarbonated flue gas 101A are reduced. The regenerator 3 releases CO₂ from the basic amine compound absorbent 103 the CO₂ absorbed therein.

Claims

1. A CO₂ recovery method, comprising the steps of:

bringing flue gas into contact with a basic amine compound absorbent so that the basic amine compound absorbent absorbs CO₂ contained in the flue gas;

washing the decarbonated flue gas in which an amount of CO₂ has been reduced with circulating wash water by bringing the decarbonated flue gas into contact with the wash water so that amounts of basic amine compounds entrained in the decarbonated flue gas are reduced;

releasing CO₂ from the basic amine compound absorbent containing the CO₂ absorbed therein; and

concentrating the wash water and delivering condensed water generated during concentration to the step of washing with the wash water;

wherein the step of washing the decarbonated flue gas in which an amount of CO₂ has been reduced with circulating wash water by bringing the decarbonated flue gas into contact with the wash water so that amounts of basic amine compounds entrained in the decarbonated flue gas are reduced is performed at a plurality of stages in a flow path through which the decarbonated flue gas flows upward, and wherein, in the step of concentrating the wash water, the wash water from the step of washing performed at an uppermost stage is concentrated to form a concentrated solution, the concentrated solution being delivered to the step of washing performed at a lower stage in the flow path, the condensed water being returned to the step of washing performed at the uppermost stage.