System and method for recovering gas containing co2 and h2s

Patent metadata

Field	Value
Publication number	US-2015361364-A1
Application number	US-201414763924-A
Country	US
Kind code	A1
Filing date	Jan 22, 2014
Priority date	Feb 21, 2013
Publication date	Dec 17, 2015
Grant date	—

Abstract

The system is provided with: a first heat exchanger which is interposed at an intersection between a rich solution supply line and a lean solution supply line, which has absorbed CO 2 and H 2 S extracted from a bottom portion of an absorber, and a regenerated absorbent; a second heat exchanger which is interposed at an intersection between a semi-rich solution supply line and a branch line branched at the branch portion C from the lean solution supply line, and the lean solution; a merging portion which merges a branch line configured to supply the lean solution after heat exchange with the lean solution supply line; and a flow rate adjusting valve which is interposed in the lean solution supply line to adjust the distribution amount of the lean solution.

First claim

1 . A system for recovering a gas containing CO 2 and H 2 S, comprising:
an absorber which brings an introduction gas containing CO 2 and H 2 S into contact with an absorbent which absorbs CO 2 and H 2 S to absorb CO 2 and H 2 S from the introduction gas; an absorbent regenerator which extracts the absorbent, which has absorbed CO 2 and H 2 S, from a bottom portion of the absorber, introduces the absorbent from a top portion side via a rich solution supply line, and releases CO 2 and H 2 S by the heat of a reboiler to regenerate the absorbent; a lean solution supply line which returns the regenerated absorbent to the absorber; a semi-rich solution supply line which extracts the absorbent, which has absorbed a part of CO 2 and H 2 S from the vicinity of a middle stage of the absorber, and introduces the extracted absorbent into the vicinity of the middle stage of the regenerator; a first heat exchanger which is interposed at an intersection between the rich solution supply line and the lean solution supply line to perform the heat exchange between the absorbent, which has absorbed CO 2 and H 2 S extracted from the bottom portion of the absorber, and the regenerated absorbent; a second heat exchanger which is interposed at an intersection between the semi-rich solution supply line and a branch line branched at a branch portion of the lean solution supply line to perform heat exchange between the absorbent, which has absorbed CO 2 and H 2 S extracted from the vicinity of the middle stage of the absorber, and the regenerated absorbent; a merging portion which merges the branch line configured to supply the lean solution after the heat exchange in the second heat exchanger with the lean solution supply line; and a flow rate adjusting valve which is interposed in the lean solution supply line to adjust a distribution amount of the lean solution.

2 . The system for recovering a gas containing CO 2 and H 2 S according to claim 1 , comprising:
a first bypass line which bypasses the rich solution from the rich solution supply line side to the semi-rich solution supply line side on an upstream side of the first heat exchanger interposed in the rich solution supply line and introduces the rich solution to the second heat exchanger; a second bypass line which returns the rich solution, which is bypassed and heat-exchanged to the rich solution supply line side from the semi-rich solution supply line side on a downstream side of the second heat exchanger interposed in the semi-rich solution supply line, to the rich solution supply line; a control unit which performs the control of switching the bypass line by a gas type information to be introduced; and a flow rate adjusting valve which is provided on an extraction side of the semi-rich solution supply line, and stops the extraction of the semi-rich solution by the command from the control unit.

3 . A method for recovering a gas containing CO 2 and H 2 S using an absorber and a regenerator which recover CO 2 and H 2 S from an introduction gas containing CO 2 and H 2 S, the method comprising:
extracting a part of an absorbent from the vicinity of a middle stage of the absorber configured to absorb CO 2 and H 2 S from the introduction gas as a semi-rich solution, and reducing a flow rate of the absorbent flowing down below the absorber; introducing the absorbent, which is extracted from a bottom portion of the absorber, from the vicinity of a top portion of the regenerator, and introducing and regenerating the absorbent extracted from the vicinity of the middle stage of the absorber into the vicinity of the middle stage of the regenerator; performing the heat exchange of the absorbent extracted from the bottom portion with the lean solution from the regenerator using a first heat exchanger; branching the lean solution on the upstream side of the first heat exchanger, performing the heat exchange of the branched lean solution with the absorbent extracted from the vicinity of the middle stage of the absorber using a second heat exchanger, merging the lean solution after the heat exchange with the lean solution obtained by heat exchange in the first heat exchanger, and introducing the merged lean solution into the absorber so as to be reused.

4 . The method for recovering a gas containing CO 2 and H 2 S according to claim 3 ,
wherein a bypass line configured to introduce the rich solution into the second heat exchanger during operation of not extracting the semi-rich solution is provided, a part of the rich solution is introduced into the second heat exchanger, and the heat exchange is performed in the second heat exchanger by the branched lean solution.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Horizoe Kouji
• Katou Yuudai
• Murakami Moritoshi
• Yushima Masaki
• Ishida Kazuo

Classifications

• C10K1/005

  Carbon dioxide · CPC title

• C10K1/004

  Sulfur containing contaminants, e.g. hydrogen sulfide · CPC title

• B01D2252/2026

  Polyethylene glycol, ethers or esters thereof, e.g. Selexol · CPC title

• B01D53/1425

  Regeneration of liquid absorbents · CPC title

• B01D53/185

  Liquid distributors · CPC title