Sequential combustion arrangement with cooling gas for dilution

Abstract

A gas turbine with a sequential combustor arrangement as disclosed includes a first combustor with a first burner for admitting a first fuel into a combustor inlet gas during operation and a first combustion chamber for burning the first fuel, a dilution gas admixer for admixing a dilution gas to the first combustor combustion products leaving the first combustion chamber, a second burner for admixing a second fuel and a second combustion chamber. To assure a temperature profile after the dilution gas admixer and to increase the gas turbine's power and efficiency a vane and/or blade of the turbine has a closed loop cooling. The outlet of the closed loop cooling is connected to the dilution gas admixer for admixing the heated cooling gas leaving the vane and/or blade into the first combustor combustion products.

Claims

1. A gas turbine comprising: a compressor, a turbine, and a sequential combustor arrangement comprising: a first combustor with a first burner for admitting a first fuel into a first combustion chamber for burning the first fuel to form first combustor combustion products; a dilution gas admixer for admixing a dilution gas to the first combustor combustion products leaving the first combustion chamber; a second burner for admixing a second fuel in a second combustion chamber, wherein the first combustor, the dilution gas admixer, the second burner and the second combustion chamber are arranged sequentially and are in a fluid flow connection; a vane and/or blade of the turbine having a cooling loop which is connected to a compressor plenum for feeding compressed cooling fluid into the vane and/or blade to cool the vane and/or blade, the cooling loop of the vane and/or blade configured to internally cool the vane and/or blade without being discharged from the vane and/or blade into hot gas flowing around an exterior of the vane and/or blade, the cooling loop having an outlet connected to the dilution gas admixer, the outlet of the cooling loop being positioned and configured to pass the compressed cooling fluid that has flowed within the vane and/or blade of the turbine to the dilution gas admixer so that the compressed cooling fluid that is heated via flowing within the vane and/or blade to cool the vane and/or blade passes to the dilution gas admixer to he injected into the first combustion products as the dilution gas so that the compressed cooling fluid that was heated from passing within the vane and/or blade to cool the vane and/or blade is subsequently admixed with the first combustor combustion products via the dilution gas admixer to facilitate generation of a homogenous temperature profile for the admixed first combustion products and dilution gas to be fed to the second burner to reduce NOx emission values; the dilution gas admixer positioned upsteam of the second burner, with respect to a flow direction of the first combustor combustion products, and configured to receive the compressed cooling fluid from the outlet of the cooling loop and inject the dilution gas into the first combustor combustion products such that the compressed cooling fluid that was heated from passing within the vane and/or blade to cool the vane and or blade is admixed with the first combustor combustion products via, the dilution gas admixer to generate the homogenous temperature profile for the admixed first combustor combustion products and dilution gas to reduce NOx emission values for feeding the admixed first combustion products and dilution gas to the second burner; and an additional cooling loop to cool an additional vane and/or blade positioned upstream of the vane and/or blade, with respect to the flow direction of the first combustor combustion products, the additional cooling loop being connected to the compressor plenum to receive the compressed cooling fluid, being open to discharge from the additional vane and/or blade, and being connected to the gas admixer to provide additional compressed heated fluid to the first combustion products.

2. The gas turbine as claimed in claim 1, wherein the cooling loop has a cooling gas feed connecting the compressor plenum to the cooling loop.

3. The gas turbine as claimed in claim 2, wherein the cooling gas feed is arranged between a rotor and the sequential combustor arrangement.

4. The gas turbine as claimed in claim 2, wherein the cooling gas feed is arranged between a combustor casing and the sequential combustor arrangement.

5. The gas turbine as claimed in claim 1, comprising: a cooling channel for cooling at least one of a first combustion liner of the first combustor, a second combustor liner of the second combustor, a wall of the second burner, a mixing section, and the dilution gas admixer.

6. The gas turbine as claimed in claim 1, comprising: an ejector pump interposed between the outlet of the cooling loop and the dilution gas admixer.

7. The gas turbine as claimed in claim 1, comprising: at least one feed to the dilution gas admixer directly connected to the compressor plenum for additionally admixing compressor exit gas into the first combustor combustion products.

8. A method for operating a gas turbine having a compressor, a turbine and a sequential combustor arrangement with a first combustor having a first burner and a first combustion chamber, a dilution gas admixer, a second burner and a second combustion chamber, wherein the first combustor, the dilution gas admixer, the second burner, and second combustion chamber are arranged sequentially in a fluid now connection, the method comprising: compressing inlet gas in the compressor; burning a mixture in the first combustion chamber to obtain first combustor combustion products; passing compressed gas through a cooling loop of a vane and/or blade of the turbine so that the compressed gas is passed within the vane and/or blade to internally cool the vane and/or blade without the compressed gas passing through the vane and/or blade being discharged into hot gas flowing around an exterior of the vane and/or blade; feeding the compressed gas from the cooling loop of the vane and/or blade to the dilution gas admixer without recompression of the compressed gas after the compressed gas is passed through the cooling loop of the vane and/or blade to internally cool the vane and/or blade; generating a homogenous temperature profile of the first combustor combustion products and dilution gas to reduce NOx emission values by admixing dilution gas to the first combustor combustion products leaving the first combustion chamber in the dilution gas admixer for feeding the dilution gas admixed with the first combustor combustion products to the second burner to generate the homogenous temperature profile for the first combustor combustion products and dilution gas to reduce the NOx emission values, the dilution gas including the compressed gas fed to the dilution gas admixer from the cooling loop of the vane and/or blade to facilitate generation of the homogenous temperature profile for the admixed first combustor combustion products and dilution gas to reduce the NOx emission values; feeding the admixed dilution gas and the first combustor products having the homogenous temperature profile to the second burner; passing additional compressed gas through an additional cooling loop to cool an additional vane and/or blade positioned upstream of the vane and/or blade, with respect to a flow direction of the first combustor combustion products, the additional cooling loop being open to discharge from the additional vane and/or blade; and feeding the additional compressed gas from the additional cooling loop to the gas admixer to provide additional compressed heated fluid to the first combustor combustion products.

9. The method for operating a gas turbine according to claim 8, comprising: feeding the compressed gas from a compressor plenum into the cooling loop of the vane and/or blade.

10. The method for operating a gas turbine according to claim 8, comprising: feeding the compressed gas from a cooling gas feed to the cooling loop of the vane and/or blade, the cooling gas feed being arranged between a rotor and the sequential combustor arrangement.

11. The method for operating a gas turbine according to claim 8, comprising: feeding the compressed gas to the cooling loop from a cooling gas feed arranged between a combustor casing and the sequential combustor arrangement.

12. The method for operating a gas turbine as claimed in claim 8, the wherein the feeding of the compressed gas from the cooling loop of the vane and/or blade to the dilution gas admixer after the compressed gas is passed through the cooling loop of the vane and/or blade to internally cool the vane and/or blade comprises: passing the compressed gas from the cooling loop of the vane and/or blade through a cooling channel for cooling at least one of a first combustion liner, a second combustor liner, a wall of the second burner, and a mixing section before it is fed into the dilution gas admixer.

13. The method for operating a gas turbine as claimed in claim 8, comprising: increasing a pressure of the compressed gas leaving the cooling loop in an ejector pump before the compressed gas is fed into the dilution gas admixer.

14. The method for operating a gas turbine as claimed in claim 13, comprising: using compressed gas from a compressor plenum to increase the pressure of the compressed gas in the ejector pump.

15. The method for operating a gas turbine as claimed in claim 8, comprising: admixing the compressed gas taken directly from a compressor plenum with the first combustor combustion products in the dilution gas admixer.

16. The method for operating a gas turbine as claimed in claim 8, wherein: the passing of the compressed gas through the cooling loop of the vane and/or blade of the turbine is driven via a pressure drop of the first combustor.

17. A sequential combustor arrangement for a gas turbine comprising: a first combustor with a first burner for admitting a first fuel into a first combustion chamber for burning the first fuel to form first combustor combustion products; a dilution gas admixer positioned to receive the first combustor combustion products from the first combustion chamber; a second combustion chamber positioned downstream of the dilution gas admixer, with respect to a flow direction of the first combustor combustion products, wherein the first combustor, the dilution gas admixer, and the second combustion chamber are arranged sequentially and are in a fluid flow connection; a vane and/or blade of a turbine having a cooling loop configured to receive compressed cooling fluid within the vane and/or blade to cool the vane and/or blade, the cooling loop of the vane and/or blade configured to internally cool the vane and/or blade via the compressed cooling fluid without discharging the compressed cooling fluid from the vane and/or blade into hot gas flowing around an exterior of the vane and/or blade; the cooling loop having an outlet connected to the dilution gas admixer that is positioned and configured to pass the compressed cooling fluid from the vane and/or blade toward the dilution gas admixer so that the compressed cooling fluid that is heated via flowing within the vane and/or blade to cool the vane and/or blade is passable to the dilution gas admixer to be injected into the first combustor combustion products so that the compressed cooling fluid that was heated from passing within the vane and/or blade to cool the vane and/or blade is subsequently admixable with the first combustor combustion products via the dilution gas admixer to facilitate generation of a homogenous temperature profile for the admixed first combustor combustion products and dilution gas to reduce NOx emission values; the dilution gas admixer positioned and configured to receive the compressed cooling fluid from the outlet of the cooling loop and iniect the dilution gas into the first combustor combustion products such that the compressed cooling fluid that was heated from passing within the vane and/or blade to cool the vane and/or blade is admixed with the first combustor combustion products via, the dilution gas admixer to generate the homogenous temperature profile, for the admixed first combustor combustion products and dilution gas to reduce NOx emission values for feeding the admixed first combustor combustion products and dilution gas to the second burner; and an additional cooling loop to cool an additional vane and/or blade positioned upstream of the vane and/or blade, with respect to the flow direction of the first combustor combustion products, the additional cooling loop being connected to the compressor plenum to receive the compressed cooling fluid, being open to discharge from the additional vane and/or blade, and being connected to the gas admixer to provide additional compressed heated fluid to the first combustor combustion products.

18. The sequential combustor arrangement of claim 17, wherein the cooling loop has a Venturi nozzle at the oulet to increase a pressure of the compressed cooling fluid leaving the cooling loop.

19. The sequential combustor arrangement of claim 17, comprising: an ejector pump positioned to increase a pressure of the compressed gas before the compressed gas is fed into the dilution gas admixer.

20. The sequential combustor arrangement of claim 17, wherein the cooling loop is configured so that the compressed gas is passable through the vane and/or blade via a pressure drop of the first combustor so that the compressed cooling fluid that is heated via flowing within the vane and/or blade to cool the vane and/or blade is passable to the dilution gas admixer to be injected into the first combustion products without undergoing recompression.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure, its nature as well as its advantages, shall be described in more detail below with the aid of the accompanying schematic drawings.

(2) Referring to the drawings:

(3) FIG. 1 shows a gas turbine with a sequential combustion arrangement with a first burner, first combustion chamber, an admixer for admixing dilution gas, a second burner, a second combustion chamber and closed loop cooled vanes;

(4) FIG. 2 shows a gas turbine with a sequential combustion arrangement with a first burner, first combustion chamber, an admixer for admixing dilution gas, a second burner, a second combustion chamber and closed loop cooled vanes and a venturi nozzle to boost the pressure level of cooling gas leaving the closed loop cooling;

(5) FIG. 3 shows a gas turbine with a sequential combustion arrangement with a first burner, first combustion chamber, an admixer for admixing dilution gas, a second burner, a second combustion chamber and closed loop cooled vanes, and blades as well an ejector pump to boost the pressure level of cooling gas leaving the closed loop cooling.

EMBODIMENTS OF THE DISCLOSURE

(6) FIG. 1 shows a gas turbine 1 with a sequential combustor arrangement 4. It comprises a compressor 3, a sequential combustor arrangement 4, and a turbine 5.

(7) The sequential combustor arrangement 4 comprises a first burner 106, a first combustion chamber 101, and a dilution gas admixer 27 for admixing a dilution gas 33 to the hot gases leaving the first combustion chamber 101 during operation. Downstream of the admixer 27 the sequential combustor arrangement 4 further comprises a second burner 103, and a second combustion chamber 102. The first burner 106, first combustion chamber 101, admixer 27, second burner 103 and second combustion chamber 102 are arranged sequentially in a fluid flow connection. The sequential combustor arrangement 4 is housed in a combustor casing 31. The compressed gas 8 leaving the compressor 3 passes through a diffusor for at least partly recovering the dynamic pressure of the gas leaving the compressor 3.

(8) The turbine 5 comprises vanes 11, and blades 10. The vanes 11 are cooled with cooling gas flowing through a closed loop cooling 17. Cooling gas is fed to the closed loop cooling 17 from the compressor plenum 30 through cooling gas feeds 22. A cooling gas feed 22 can for example be arranged in the compressor plenum 30 in a region between the rotor 2 and the combustor arrangement 4, or in a region between the combustor arrangement 4 and the combustor casing 31.

(9) Open loop cooling gas 13 can be discharged from the vane 11 into the hot gas flow.

(10) During operation cooling gas which was heated in the closed loop cooling 17 is injected as dilution gas by the dilution gas admixer 27 into the first combustor combustion products 35. In this example dilution gas injection 110 is used for the dilution gas admixing.

(11) The sequential combustor arrangement 4 further comprises a first combustor liner 104 for guiding cooling gas along the walls of the first combustion chamber, and a second combustor liner 105 for guiding cooling gas along the walls of the second combustion chamber 102.

(12) A first fuel 28 can be introduced into the first burner 106 via a first fuel injection, mixed with compressed gas 8 which is compressed in the compressor 3, and burned in the first combustion chamber 101. Dilution gas 33 is admixed in the subsequent admixer 27. A second fuel 29 can be introduced into the second burner 103 via a second fuel injector, mixed with hot gas leaving the admixer 27 and burned in the second combustion chamber 102. The hot gas leaving the second combustion chamber 102 is expanded in the subsequent turbine 5, performing work. The turbine 5 and compressor 3 are arranged on a rotor 2.

(13) The remaining heat of the exhaust gas 7 leaving the turbine 5 can be further used in a heat recovery steam generator or boiler (not shown) for steam generation.

(14) In the example shown here compressed gas 8 is admixed as dilution gas 33. Typically compressed gas 8 is compressed ambient air. For gas turbines with flue gas recirculation (not shown) the compressor gas is a mixture of ambient air and recirculated flue gas.

(15) Typically, the gas turbine system includes a generator (not shown) which is coupled to a rotor 2 of the gas turbine 1. The gas turbine 1 further comprises a cooling system for the turbine 5, which is also not shown as it is not subject of the invention.

(16) The embodiment of FIG. 2 differs from the gas turbine of FIG. 1 in that the pressure of cooling gas returning from the closed loop cooling 17 of the second vane is boosted in a venturi nozzle 15 using compressed gas 8 from the compressor plenum as driving fluid 16 before it is fed into the admixer 27. Further, the cooling gas turbine from the first vane is used as cooling fluid to cool the walls of the second combustor liner 105 before it is fed into the admixer 27.

(17) The example of FIG. 2 further shows an additional dilution gas injection 33 upstream (with respect to the hot gases flowing through the combustor arrangement 4) of the location at which the heated cooling gas is injected in the admixer 27.

(18) The embodiment of FIG. 3 is also based on FIG. 1. It differs from the gas turbine of FIG. 1 in that the admixer 27 comprises a streamlined body 32 for injecting dilution gas 33 into the first combustor combustion products. At least part of the dilution gas 33 is first introduced into the streamlined body 32 and injected into first combustor combustion products 35 from the streamlined body 32. In the example shown the streamlined body 32 is arranged right at the entrance into the admixer 27. Embodiments in which the streamlined body 32 is arranged further downstream in the admixer 27 are also conceivable.

(19) The embodiment of FIG. 3 further comprises a closed loop cooling 17 for the first blade 10. Compressed gas 8 is fed via the blade cooling gas feed 12 to the closed loop cooling 17. The heated cooling gas returning from the first blade 10 is fed into the cooling channel of second combustor liner 105, flows along the second combustor liner 105 until it reaches the admixer 27 and is injected into the first combustor combustion products 35.

(20) The example further shows an injector pump 14 which is used to boost the pressure of the cooling gas returning from the closed loop cooling 17 of the second vane before it is injected via the admixer 27.

(21) For all shown arrangements can or annular architectures or any combination of the two is possible. Flame Sheet, EV, AEV or BEV burners can be used for can as well as for annular architectures.

(22) The mixing quality of the admixer II is crucial for a stable clean combustion since the burner system of the second combustion chamber 102 requires a prescribed inlet conditions.

(23) All the explained advantages are not limited to the specified combinations but can also be used in other combinations or alone without departing from the scope of the disclosure. Other possibilities are optionally conceivable, for example, for deactivating individual burners or groups of burners at part load operation. Further, the cooling gas and the dilution gas can be re-cooled in a cooling gas cooler before use as cooling gas, respectively as dilution gas.

LIST OF DESIGNATIONS

(24) 1 Gas Turbine

(25) 2 Rotor

(26) 3 Compressor

(27) 4 Sequential combustor arrangement

(28) 5 Turbine

(29) 7 Exhaust Gas

(30) 8 Compressed gas

(31) 9 Combustion Products

(32) 10 Blade

(33) 11 Vane

(34) 12 Blade cooling gas feed

(35) 13 Open loop cooling gas

(36) 14 Ejector pump

(37) 15 Venturi nozzle

(38) 16 Driving fluid

(39) 17 Closed loop cooling

(40) 22 Vane cooling gasfeed

(41) 27 Dilution gas admixer

(42) 28 First fuel injection

(43) 29 Second fuel injection

(44) 30 Compressor plenum

(45) 31 Combustor casing

(46) 32 Streamlined body

(47) 33 Dilution gas

(48) 34 Mixing section

(49) 35 First combustion products

(50) 36 Dilution gas control valve

(51) 101 First combustion chamber

(52) 102 Second combustion chamber

(53) 103 Second burner

(54) 104 First combustor liner

(55) 105 Second cornbustor liner

(56) 106 First burner

(57) 110 Dilution gas injection