Sequential combustion with dilution gas mixer

Patent metadata

Field	Value
Publication number	US-9885481-B2
Application number	US-201414445162-A
Country	US
Kind code	B2
Filing date	Jul 29, 2014
Priority date	Aug 15, 2013
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

The invention refers to a sequential combustor arrangement including a first burner, a first combustion chamber, a dilution burner for admixing a dilution gas and a second fuel via a dilution-gas-fuel-admixer to the first combustor combustion products. The dilution-gas-fuel-admixer has at least one streamlined body which is arranged in the dilution burner for introducing the at least one second fuel into the dilution burner through at least one fuel nozzle, and which has a streamlined cross-sectional profile and which extends with a longitudinal direction perpendicularly or at an inclination to a main flow direction prevailing in the dilution burner. The streamlined body includes a dilution gas opening for admixing dilution gas into the first combustor combustion products upstream of the at least one fuel nozzle. The disclosure further refers to a method for operating a gas turbine with such a sequential combustor arrangement.

First claim

The invention claimed is:

1. A method for operating a gas turbine comprising a compressor, a sequential combustor arrangement and a turbine, the sequential combustor arrangement comprising a first burner, a first combustion chamber, a dilution burner having a dilution-gas-fuel-admixer, and a second combustion chamber arranged sequentially in a fluid flow connection with the first combustion chamber and the dilution burner, the method comprising:
compressing an inlet gas in the compressor;
admixing a first fuel with the compressed inlet gas to form a first mixture in the first burner;
burning the first mixture in the first combustion chamber to obtain first combustion products;
admixing a dilution gas and a second fuel, using the dilution-gas-fuel-admixer, with the first combustion products to form a second mixture;
burning the second mixture in the second combustion chamber to obtain second combustion products; and
expanding the second combustion products in the turbine;
wherein the dilution-gas-fuel-admixer comprises at least one streamlined body arranged in the dilution burner, the at least one streamlined body comprising at least one fuel nozzle for introducing the second fuel and a streamlined cross-sectional profile, the at least one streamlined body extending in a longitudinal direction from a first side of the dilution burner to a second side of the dilution burner perpendicularly or at an inclination to a main flow direction of the first combustion products entering the dilution burner, wherein the at least one streamlined body further comprises at least one dilution gas opening for introducing dilution gas into the first combustion products upstream of each of the at least one fuel nozzle and a vortex generator, the at least one dilution gas opening being formed as a slot, the slot extending along the at least one streamlined body in the longitudinal direction of the at least one streamlined body and having a slot height perpendicular to the longitudinal direction of the at least one streamlined body, wherein the slot height increases linearly from an inner slot height to an outer slot height along the longitudinal direction of the streamlined body.

2. The method as claimed in claim 1 , wherein a ratio of a mass flow of first combustion products entering the dilution burner to a mass flow of dilution gas admixed through the at least one dilution gas opening is in a range of 0.5 to 2, or alternatively the ratio is in a range of 0.7 to 1.5, and further alternatively the ratio is in a range of 0.9 to 1.1.

3. The method as claimed in claim 1 , wherein the dilution gas is introduced through the at least one dilution gas opening in a direction parallel to, or within a maximum deviation of 20° to, a flow direction of the first combustion products at a location of the at least one dilution gas opening.

4. The method as claimed in claim 1 , wherein the dilution gas is introduced through the at least one dilution gas opening at an average velocity which is the same as, or within a maximum deviation of 30% of, an average flow velocity of the first combustion products at a location of the at least one dilution gas opening.

5. The method as claimed in claim 1 , wherein the at least one dilution gas opening comprises at least two dilution gas openings, which extend from lateral surfaces of the at least one streamlined body.

6. A sequential combustor arrangement comprising:
a first burner;
a first combustion chamber;
a dilution burner comprising a dilution-gas-fuel-admixer for admixing a dilution gas and at least one fuel to first combustion products leaving the first combustion chamber during operation; and
a second combustion chamber arranged sequentially in a fluid flow connection with the first combustion chamber and the dilution burner;
wherein the dilution-gas-fuel-admixer comprises at least one streamlined body arranged in the dilution burner for introducing the at least one fuel into the dilution burner through at least one fuel nozzle, the at least one streamlined body having a streamlined cross-sectional profile and extending in a longitudinal direction from a first side of the dilution burner to a second side of the dilution burner perpendicularly or at an inclination to a main flow direction of the first combustion products entering the dilution burner, wherein the at least one streamlined body comprises at least one dilution gas opening for introducing dilution gas into the first combustion products upstream of each of the at least one fuel nozzle and a vortex generator, the at least one dilution gas opening being formed as a slot, the slot extending along the at least one streamlined body in the longitudinal direction of the at least one streamlined body and having a slot height perpendicular to the longitudinal direction of the at least one streamlined body, wherein the slot height increases linearly from an inner slot height to an outer slot height along the longitudinal direction of the streamlined body.

7. The sequential combustor arrangement as claimed in claim 6 , wherein the at least one dilution gas opening is capable of providing a mass flow of dilution gas such that during operation a ratio of a mass flow of the first combustion products to the mass flow of dilution gas is in a range of 0.5 to 2.

8. The sequential combustor arrangement as claimed in claim 6 , wherein the at least one dilution gas opening is configured to introduce dilution gas parallel to the main flow direction of the first combustion products entering the dilution burner.

9. The sequential combustor arrangement as claimed in claim 6 , wherein a ratio of a flow area for first combustion products to a flow area of the dilution gas opening is in a range of 1 to 10.

10. The sequential combustor arrangement as claimed in claim 6 , wherein the at least one dilution gas opening comprises at least two dilution gas openings for introducing dilution gas into the first combustion products, the at least one streamlined body further comprising two lateral surfaces wherein the at least two dilution gas openings extend along the lateral surfaces.

11. The sequential combustor arrangement as claimed in claim 6 , wherein the vortex generator is arranged on at least one lateral surface of the at least one streamlined body or, alternatively, the vortex generator is located on a trailing edge of the at least one streamlined body and includes at least two lobes extending in opposite transverse directions with respect to a central plane of the at least one streamlined body.

12. The sequential combustor arrangement as claimed in claim 7 , wherein the ratio of the mass flow of the first combustion products to the mass flow of dilution gas is in a range of 0.7 to 1.5.

13. The sequential combustor arrangement as claimed in claim 12 , wherein the ratio of the mass flow of the first combustion products to the mass flow of dilution gas is in a range of 0.9 to 1.1.

14. The sequential combustor arrangement as claimed in claim 1 , wherein a ratio of a flow area for the first combustion products to a flow area of the dilution gas opening is in a range of 1 to 10.

15. The sequential combustor arrangement as claimed in claim 14 , wherein the ratio of the flow area for the first combustion products to the flow area of the dilution gas opening is in a range of 2 to 7.

16. The sequential combustor arrangement as claimed in claim 15 , wherein the ratio of the flow area for the first combustion products to the flow area of the dilution gas opening is in a range of 4 to 6.

Assignees

• Ansaldo Energia Switzerland AG

Inventors

• Duesing Michael

Classifications

• F23R3/16

  with devices inside the flame tube or the combustion chamber to influence the air or gas flow · CPC title

• F02C7/228

  Dividing fuel between various burners · CPC title

• F23R3/34

  Feeding into different combustion zones · CPC title

• F23R3/26 Primary

  Controlling the air flow · CPC title

• F23R3/20 Primary

  incorporating fuel injection means · CPC title