EXHAUST GAS TREATMENT SYSTEM

• US 20140041523A1
• Filed: 08/09/2012
• Published: 02/13/2014
• Est. Priority Date: 08/09/2012
• Status: Abandoned Application

• Current Assignee: Mitsubishi Heavy Industries, Ltd.
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Tsujiuchi, Tatsuya, Honjo, Shintaro, Yonekawa, Takahito, Sugita, Satoru, Ito, Motofumi, Kamijo, Takashi, Nagayasu, Tatsuto, Okamoto, Takuya, Wu, Tiffany
• Application Number:
  US13/571,001
• Publication Number:
  US 20140041523A1
• Time in Patent Office: Days
• US Class Current: 96/218
• CPC Class Codes: B01D 2252/204 Amines
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2258/0283 Flue gases
• CPC Class Codes: B01D 53/1425 Regeneration of liquid absorbents
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01D 53/343 Heat recovery
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01D 53/78 with gas-liquid contact
• CPC Class Codes: C01B 32/50 Carbon dioxide
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/10 Process efficiency
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2
• CPC Class Codes: Y02P 20/50 Improvements relating to the production of bulk chemicals

Abstract

There is provided an exhaust gas treatment system including a CO₂ recovery unit with further enhanced energy efficiency. An exhaust gas treatment system (1) of the present invention includes: a CO₂ recovery unit (10) including a CO₂ absorption column (11), an absorbing solution regeneration column (16), and a reboiler (21); and an exhaust gas heat exchanger (5) provided on a gas upstream side of the CO₂ recovery unit (10). Heat exchange is performed between process condensate discharged from the CO₂ absorption column (11) and steam condensate discharged from the reboiler (21) in a heat exchanger (22). The heated process condensate is fed to the absorbing solution regeneration column (16). Heat exchange is performed between the cooled steam condensate and exhaust gas in the exhaust gas heat exchanger (5) so that the steam condensate is heated while the exhaust gas is cooled.

Claims

1. An exhaust gas treatment system provided on a downstream side of a boiler which combusts fuel to heat water and generate water vapor, comprising:

a CO₂ recovery unit including;

a CO₂ absorption column for bringing exhaust gas containing CO₂ generated in the boiler into contact with a CO₂ absorbing solution so that the CO₂ absorbing solution absorbs the CO₂ and thereby the CO₂ is removed out of the exhaust gas;

an absorbing solution regeneration column for desorbing the CO₂ from the CO₂ absorbing solution which absorbed the CO₂ to regenerate the CO₂ absorbing solution; and

a reboiler for heating the CO₂ absorbing solution discharged from the absorbing solution regeneration column with water vapor and feeding the vaporized CO₂ absorbing solution to the absorbing solution regeneration column; and

an exhaust gas heat exchanger provided on a gas upstream side of the CO₂ recovery unit, wherein

the water vapor is supplied from the boiler to the reboiler, where heat exchange is performed between the CO₂ absorbing solution and the water vapor so that the water vapor is cooled into steam condensate,

heat exchange is performed between the CO₂ absorbing solution discharged from the CO₂ absorption column and the steam condensate discharged from the reboiler in a heat exchanger so that the CO₂ absorbing solution is heated while the steam condensate is cooled,

the CO₂ absorbing solution heated in the heat exchanger is fed to the absorbing solution regeneration column, and

heat exchange is performed between the cooled steam condensate and the exhaust gas in the exhaust gas heat exchanger so that the steam condensate is heated while the exhaust gas is cooled.

2. The exhaust gas treatment system according to claim 1, wherein the CO₂ absorbing solution is process condensate discharged from a water washing section in the CO₂ absorption column.

3. The exhaust gas treatment system according to claim 1, wherein the CO₂ absorbing solution is a solution discharged from a bottom portion of the CO₂ absorption column.

4. The exhaust gas treatment system according to claim 1, wherein heat exchange is performed between the CO₂ absorbing solution and the exhaust gas in the exhaust gas heat exchanger so that the CO₂ absorbing solution is heated while the exhaust gas is cooled, and the heated CO₂ absorbing solution is supplied to the absorbing solution regeneration column.

5. The exhaust gas treatment system according to claim 1, wherein the steam condensate heated in the exhaust gas heat exchanger is supplied to the reboiler.

6. The exhaust gas treatment system according to claim 1, wherein the steam condensate heated in the exhaust gas heat exchanger is supplied to the boiler.