Method of recovering carbon dioxide and recovery apparatus

Patent metadata

Field	Value
Publication number	US-9545601-B2
Application number	US-201414473617-A
Country	US
Kind code	B2
Filing date	Aug 29, 2014
Priority date	Apr 24, 2012
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

The carbon dioxide recovery method and apparatus are capable of reducing energy for regenerating the absorbing liquid and operating cost. An absorption column has first and second absorbing sections that a gas is supplied through the first absorbing section to the second absorbing section and the absorbing liquid absorbs carbon dioxide. A regeneration column regenerating the absorbing liquid has first and second regenerating sections. The first regenerating section has an external heating implement and the second regenerating section is heated by the gas discharged from the first regeneration section. Circulation mechanism has a circulation system circulating the absorbing liquid between the second absorbing section and the first regenerating section, and a branch path branched from the circulation system. A part of the absorbing liquid circulating the circulation system flows from the second absorbing section through the first absorbing section and the second regenerating section successively to the first regenerating section.

First claim

What is claimed is:

1. A carbon dioxide recovery apparatus, comprising:
an absorption column configured to bring a gas into contact with an absorbing liquid and to allow the absorbing liquid to absorb carbon dioxide contained in the gas, the absorption column having a first absorbing section and a second absorbing section which are arranged to supply the gas from the first absorbing section to the second absorbing section;
a regeneration column that regenerates the absorbing liquid, configured to heat the absorbing liquid having carbon dioxide absorbed in the absorption column to cause the absorbing liquid to release the carbon dioxide, the regeneration column having a first regenerating section having an external heating implement and a second regenerating section arranged to be heated by heat from gas discharged from the first regenerating section; and
a circulating mechanism comprising a circulation system configured to circulate the absorbing liquid between the second absorbing section and the first regenerating section, and a branch flow system branched from the circulation system to cause a part of the absorbing liquid circulated in the circulation system to flow from the second absorbing section through the first absorbing section and the second regenerating section successively, and be directed to the first regenerating section,
wherein the branch flow system has a first path branched from the circulation system to supply the absorbing liquid from the second absorbing section to the first absorbing section, a second path for supplying the absorbing liquid from the first absorbing section to the second regenerating section, and a third path extended from the second regenerating section to be joined with the circulation system, and the circulation system has a first path and a second path which are branched from each other and cause the absorbing liquid of the first regenerating section to return to the second absorbing section,
the first path of the branch flow system has a cooler for cooling the absorbing liquid to be supplied into the first absorbing section,
the circulating mechanism has a first heat exchanger, a second heat exchanger, and a third heat exchanger,
wherein the first heat exchanger makes heat exchange between the first path of the circulation system and the third path of the branch flow system,
wherein the second heat exchanger makes heat exchange between the absorbing liquid to be supplied from the second absorbing section to the first regenerating section in the circulation system, and the absorbing liquid in the second path of the circulation system, and
wherein the third heat exchanger makes heat exchange, at the downstream side of the first heat exchanger in the first path of the circulation system, between the first path of the circulation system and the second path of the branch flow system.

2. The carbon dioxide recovery apparatus according to claim 1 , wherein the second regenerating section has no external heating implement.

3. The carbon dioxide recovery apparatus according to claim 1 , wherein a temperature at which the absorbing liquid flowing in the branch flow system is supplied to the second regenerating section is lower than a temperature at which the absorbing liquid circulated in the circulation system is supplied to the first regenerating section.

4. The carbon dioxide recovery apparatus according to claim 1 , wherein the circulation system further has a path and a heat exchanger for heating a part of the absorbing liquid to be supplied from the second absorbing section to the first regenerating section, using afterheat in the external heating implement of the regeneration column.

5. The carbon dioxide recovery apparatus according to claim 1 , wherein the absorption column has two columns independent from each other into which the first absorbing section and the second absorbing section are distributed, respectively, and the regeneration column has two columns independent from each other into which the first regenerating section and the second regenerating section are distributed, respectively.

6. The carbon dioxide recovery apparatus according to claim 1 , wherein the regeneration column further has a third regenerating section which is heated by heat from gas discharged from the second regenerating section, and the branch flow system of the circulating mechanism is configured to cause the absorbing liquid to pass from the first absorbing section to the second regenerating section through the third regenerating section.

7. The carbon dioxide recovery apparatus according to claim 1 , wherein the regeneration column further has a third regenerating section which is heated by heat from gas discharged from the second regenerating section, and the branch flow system of the circulating mechanism has an additional path which is branched from the branch flow system to cause a part of the absorbing liquid circulating in the circulating system to pass from the second absorbing section through the first absorbing section and the third regenerating section successively and to be directed then to the first regenerating section.

8. The carbon dioxide recovery apparatus according to claim 1 , wherein the circulation system and the branch flow system are connected to each other in such a manner that the absorbing liquid which is supplied from the second absorbing section to the first regenerating section in the circulation system is joined with the absorbing liquid in the third path of the branch flow system at the downstream side of the second heat exchanger.

9. The carbon dioxide recovery apparatus according to claim 8 , wherein the circulation system has a tank in which the absorbing liquid to be supplied from the second absorbing section into the first regenerating section is stored at the upstream side of the second heat exchanger.

Assignees

• Ihi Corp

Inventors

• Nakamura Shiko
• Yamanaka Yasuro
• Takano Kenji
• Okuno Shinya

Classifications

• C01B32/50

  Carbon dioxide · CPC title

• B01D53/1406

  Multiple stage absorption · CPC title

• B01D53/1425

  Regeneration of liquid absorbents · CPC title

• B01D53/62 Primary

  Carbon oxides · CPC title

• B01D53/96

  Regeneration, reactivation or recycling of reactants · CPC title