Carbon dioxide recovery system and method

Patent metadata

Field	Value
Publication number	US-9242204-B2
Application number	US-201013503573-A
Country	US
Kind code	B2
Filing date	Dec 17, 2010
Priority date	Dec 28, 2009
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

The carbon dioxide recovery system includes: a first steam line 21 a through which low-pressure steam 14 L is fed from an intermediate-pressure turbine 12 to a low-pressure turbine 13 ; a second steam line 21 b into which the low-pressure steam 14 L is branched from the first steam line 21 a ; a first regulation valve V 1 for regulating the opening of the low-pressure steam 14 L from 100% to 0%; a second regulation valve V 2 for regulating the opening of the low-pressure steam 14 L from 0% to 100% depending on the amount of control provided to the first regulation valve V 1 ; a first auxiliary turbine 22 A for recovering power using the low-pressure steam 14 L being fed; and a first steam feed line 25 L through which exhaust steam 23 discharged from the first auxiliary turbine 22 A is supplied as a source of heat to a reboiler 24.

First claim

The invention claimed is:

1. A carbon dioxide recovery system, comprising:
a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine;
a boiler for producing steam to drive the turbines;
a carbon dioxide recovery unit including a carbon dioxide absorber for allowing a carbon dioxide absorbent to absorb and reduce carbon dioxide in a combustion flue gas discharged from the boiler and a carbon dioxide regenerator for regenerating the carbon dioxide absorbent having absorbed carbon dioxide as a regenerated carbon dioxide absorbent;
a first steam line through which low-pressure steam is fed from the intermediate-pressure turbine to the low-pressure turbine;
a second steam line into which the low-pressure steam is branched from the first steam line;
a first regulation valve disposed on the first steam line to regulate an opening of an amount of steam of the low-pressure steam from 100% to 0%;
a second regulation valve disposed on the second steam line to regulate an opening of an amount of steam of the low-pressure steam from 0% to 100% depending on the amount of control provided to the first regulation valve;
a first auxiliary turbine coupled to the second steam line to recover power using the low-pressure steam being fed;
a first steam feed line through which exhaust steam discharged from the first auxiliary turbine is employed to be fed as a source of heat to a reboiler which is used to regenerate the carbon dioxide absorbent having absorbed carbon dioxide in the carbon dioxide regenerator;
a bleed line through which the low-pressure steam having been bled from the first auxiliary turbine is fed to the low-pressure turbine; and
a control device configured to control driving of the first auxiliary turbine by controlling an opening from 100% to 0% and from 0% to 100% in carbon dioxide recovery and non-recovery modes in response to a variation in operation load of the boiler or the turbines while a pressure of the exhaust steam supplied to the reboiler is maintained to take on a permissible value for a reboiler optimum pressure (about 0.33 MPa±0.05 MPa) with the first regulation valve and the second regulation valve being operated in response to each other.

2. A carbon dioxide recovery method including using the carbon dioxide recovery system according to claim 1 to recover carbon dioxide which has been absorbed in the carbon dioxide absorbent.

Assignees

• Iijima Masaki
• Mitsubishi Heavy Ind Ltd

Inventors

• Iijima Masaki

Classifications

• Y02C20/40

  of CO2 · CPC title

• B01D2252/20484

  with one hydroxyl group · CPC title

• B01D2252/20489

  with two or more hydroxyl groups · CPC title

• F23J2215/50

  Carbon dioxide · CPC title

• F01K17/02

  for heating purposes, e.g. industrial, domestic (F01K17/06 takes precedence; domestic- or space-heating systems, e.g. central-heating systems, in general F24D1/00, F24D3/00, F24D9/00) · CPC title