System and method for recovering gas containing CO2 and H2S

Patent metadata

Field	Value
Publication number	US-9840675-B2
Application number	US-201414763924-A
Country	US
Kind code	B2
Filing date	Jan 22, 2014
Priority date	Feb 21, 2013
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

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

The invention claimed is:

1. 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 CO2 and H 2 S, the method comprising:
extracting a part of an absorbent from the vicinity of a middle stage of the absorber as a semi-rich solution which has absorbed a part of CO 2 and H 2 S from the introduction gas to reduce a flow rate of the absorbent flowing down below the absorber, and introducing the semi-rich solution into the vicinity of a middle stage of the regenerator to be regenerated;
extracting the absorbent from a bottom portion of the absorber as a rich solution which has absorbed CO 2 and H 2 S from the introduction gas, and introducing the rich solution into the vicinity of a top portion of the regenerator to be regenerated;
extracting the regenerated absorbent from a bottom of the regenerator as a lean solution which has released CO2 and H2S;
performing heat exchange of the rich solution with the lean solution in a first heat exchanger;
branching the lean solution prior to the heat exchange in the first heat exchanger;
performing heat exchange of the branched lean solution with the semi-rich solution in a second heat exchanger; and
merging the branched lean solution after the heat exchange in the second heat exchanger with the lean solution after the heat exchange in the first heat exchanger, and introducing the merged lean solution into the vicinity of a top portion of the absorber so as to be reused;
wherein a part of the rich solution is introduced into the second heat exchanger through a bypass line during operation of not extracting the semi-rich solution, and is subjected to heat exchange with the branched lean solution in the second heat exchanger.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

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

Classifications

• B01D2252/20489

  with two or more hydroxyl groups · CPC title

• C10K1/004

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

• B01D53/1425

  Regeneration of liquid absorbents · CPC title

• B01D53/1468

  Removing hydrogen sulfide · CPC title

• B01D53/1462

  Removing mixtures of hydrogen sulfide and carbon dioxide · CPC title