System and method for protecting components in a gas turbine engine with exhaust gas recirculation

Patent metadata

Field	Value
Publication number	US-9611756-B2
Application number	US-201314066488-A
Country	US
Kind code	B2
Filing date	Oct 29, 2013
Priority date	Nov 2, 2012
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

A system includes a gas turbine engine that includes a combustor section having one or more combustors configured to generate combustion products, a turbine section having one or more turbine stages between an upstream end and a downstream end, an exhaust section disposed downstream from the downstream end of the turbine section, and a fluid supply system coupled to the exhaust section. The one or more turbine stages are driven by the combustion products. The exhaust section has an exhaust passage configured to receive the combustion products as an exhaust gas. The fluid supply system is configured to route a cooling gas to the exhaust section. The cooling gas has a temperature lower than the exhaust gas. The cooling gas includes an extracted exhaust gas, a gas separated from the extracted exhaust gas, carbon dioxide, carbon monoxide, nitrogen oxides, or a combination thereof.

First claim

The invention claimed is:

1. A system, comprising:
a gas turbine engine, comprising:
a combustor section having one or more combustors configured to generate combustion products;
a turbine section having one or more turbine stages between an upstream end and a downstream end, wherein the one or more turbine stages are driven by the combustion products;
an exhaust section disposed downstream from the downstream end of the turbine section, wherein the exhaust section comprises an exhaust passage configured to receive the combustion products as an exhaust gas, and a manway configured to provide access to an interior of the exhaust section, wherein the manway comprises one or more openings fluidly coupled to the exhaust passage; and
a fluid supply system coupled to the exhaust section, wherein the fluid supply system is configured to process a cooling gas and to route the cooling gas to the exhaust section and through the manway to the interior of the exhaust section, wherein the cooling gas has a temperature lower than the exhaust gas, wherein at least a portion of the cooling gas is configured to exit the interior of the exhaust section into the exhaust passage through the one or more openings of the manway, wherein the cooling gas comprises an extracted exhaust gas, a gas separated from the extracted exhaust gas, carbon dioxide, carbon monoxide, nitrogen oxides, or a combination thereof, and the cooling gas comprises less than 10000 parts per million by volume (ppmv) of oxygen.

2. The system of claim 1 , wherein the exhaust section comprises a cooling gas passage coupled to the fluid supply system, and the cooling gas passage extends through at least one wall along the exhaust passage.

3. The system of claim 2 , wherein the cooling gas passage extends through at least one of an outer shroud cavity surrounding the exhaust passage, an inner shroud cavity surrounded by the exhaust passage, a vane protruding into the exhaust passage, a bearing cavity having a bearing assembly, or a combination thereof.

4. The system of claim 1 , wherein the gas turbine engine comprises a bearing assembly disposed within a bearing cavity of a bearing housing, and the fluid supply system is coupled to the bearing housing to route the cooling gas to the bearing housing.

5. The system of claim 1 , wherein the fluid supply system is coupled to an exhaust gas extraction system, an exhaust gas treatment system, an exhaust gas recirculation system, a carbon capture system, a gas separator, a gas purifier, a storage tank, a pipeline, or any combination thereof.

6. The system of claim 1 , wherein the gas turbine engine comprises:
a compressor section having an exhaust gas compressor driven by the turbine section, wherein the exhaust gas compressor is configured to compress and route the exhaust gas to the turbine combustor.

7. The system of claim 6 , comprising an exhaust gas extraction system coupled to the gas turbine engine, and a hydrocarbon production system coupled to the exhaust gas extraction system.

8. The system of claim 6 , wherein the gas turbine engine is a stoichiometric exhaust gas recirculation (SEGR) gas turbine engine.

9. A system, comprising:
a turbine exhaust section configured to mount downstream from a turbine section of a gas turbine engine, wherein the turbine exhaust section comprises an exhaust passage configured to receive exhaust gas from the turbine section, a cooling gas passage extending through a structure of the turbine exhaust section, and a manway configured to provide access to an interior of the turbine exhaust section, wherein the manway extends through a casing of the turbine exhaust section and the cooling passage; and
a fluid supply system coupled to the turbine exhaust section, wherein the fluid supply system is configured to process a cooling gas and to route the cooling gas to the cooling gas passage in the turbine exhaust section, wherein the cooling gas has a temperature lower than the exhaust gas, wherein the cooling gas comprises an extracted exhaust gas, a gas separated from the extracted exhaust gas, carbon dioxide, carbon monoxide, nitrogen oxides, or a combination thereof, and the cooling gas comprises less than 10000 parts per million by volume (ppmv) of oxygen.

10. The system of claim 9 , wherein the cooling gas passage is isolated from the exhaust passage.

11. The system of claim 9 , wherein the fluid supply system comprises a temperature control system, a pressure control system, a moisture removal system, a particulate removal system, or any combination thereof.

12. The system of claim 9 , wherein the manway comprises a seal configured to contain a flow of the cooling gas within the manway.

13. The system of claim 9 , wherein the turbine exhaust section comprises a vent coupled to the interior of the turbine exhaust section, wherein the vent is configured to withdraw the cooling gas from the interior of the turbine exhaust section.

14. A method, comprising:
combusting a fuel with an oxidant and an exhaust gas in a combustion portion of a turbine combustor to generate combustion products;
driving a turbine with the combustion products from the turbine combustor;
expanding and cooling the combustion products from the turbine through an exhaust passage in an exhaust section;
routing a cooling gas from a fluid supply system to the exhaust section, wherein the cooling gas comprises an extracted exhaust gas, a gas separated from the extracted exhaust gas, carbon dioxide, carbon monoxide, nitrogen oxides, or a combination thereof, and the cooling gas comprises less than 10000 parts per million by volume (ppmv) of oxygen;
routing the cooling gas from the fluid supply system to an inner shroud cavity of the exhaust section through a manway of the exhaust section; and
routing the cooling gas from the inner shroud cavity to the exhaust passage through one or more openings of the manway.

15. The method of claim 14 , comprising routing the cooling gas from the fluid supply system to an outer shroud cavity of the exhaust section, wherein the outer shroud cavity is disposed between an outer shroud and a casing of the exhaust section, and the outer shroud extends circumferentially about the exhaust passage.

16. The method of claim 14 , comprising routing the cooling gas from the fluid supply system to an internal vane cavity of a vane, wherein the vane extends into the exhaust passage of the exhaust section.

17. The method of claim 14 , wherein the inner shroud cavity of the exhaust section comprises an inner shroud that extends circumferentially about the inner shroud cavity, and the exhaust passage extends circumferentially about the inner shroud.

18. The method of claim 14 , wherein the inner shroud cavity comprises a bearing cavity of the exhaust section, wherein the bearing cavity comprises a bearing assembly.

19. The method of claim 14 , comprising sealing a flow of the cooling gas within the manway of the exhaust section.

20. The method of claim 14 , comprising venting the cooling gas directly from the inner shroud cavity of the turbine exhaust section after circulating the cooling gas through the inner shroud cavity.

Assignees

• Gen Electric
• Exxonmobil Upstream Res Co

Inventors

• Biyani Pramod K
• Leyers Scott Walter
• Miranda Carlos Miguel

Classifications

• F02M26/22

  with coolers in the recirculation passage · CPC title

• F01D25/30 Primary

  Exhaust heads, chambers, or the like · CPC title

• F02C7/18

  the medium being gaseous, e.g. air {(F02C7/125 takes precedence)} · CPC title

• Y02E20/16

  Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT] · CPC title

• F02C3/34

  with recycling of part of the working fluid, i.e. semi-closed cycles with combustion products in the closed part of the cycle · CPC title