JP2005241178A - Combustion device of gas turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion device of a gas turbine excellent in flame keeping properties for stably keeping flame by forming a back-flow area of mixed gas in a combustion chamber in a well-balanced manner without irregularity in intensity. <P>SOLUTION: At a top part of an inner cylinder 10 of the combustion device, a plurality of first fuel injection holes 26 for injecting fuel F to the combustion chamber C are coaxially provided with the inner cylinder 10. For the first fuel injection holes 26, inside/outside air passages 28, 29 for supplying air CA to the combustion chamber C are provided inside and outside of the inner cylinder in a diameter direction. Part of fuel F is injected from the second fuel injection holes 32 to the inner air passage 28. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a backflow can type combustor used in a gas turbine.

A backflow can type combustor injects gaseous fuel and air into a combustion chamber in an inner cylinder, and forms a backflow region of an air-fuel mixture in the primary combustion region of the combustion chamber for combustion (for example, Patent Document 1).
JP 2002-206741 A

However, in the conventional combustor, unbalance is likely to occur in the reverse flow region formed in the primary combustion region of the combustion chamber due to the shape of the top of the inner cylinder and the restriction of the position of the axial swirler provided in the air passage. That is, a weak air-fuel mixture reverse flow region is formed at the center of the inner cylinder of the primary combustion region, and a strong air-fuel mixture reverse flow region is formed around the outer periphery. For this reason, the flame in the primary combustion region tends to become unstable.

  Accordingly, the present invention provides a combustor for a gas turbine excellent in flame holding ability, in which a backflow region of an air-fuel mixture in a primary combustion region is formed in a well-balanced manner without being strong and weak and can stably hold a flame. Objective.

  In order to achieve the above object, the present invention comprises an inner cylinder that forms a combustion chamber therein, and an outer cylinder that covers the outside of the inner cylinder, and a compressor is provided between the inner cylinder and the outer cylinder. A combustor in which an air introduction passage is formed to introduce air from the inner cylinder in a direction opposite to the outflow direction of the combustion gas from the inner cylinder toward the turbine, and is disposed concentrically with the inner cylinder at the top of the inner cylinder A plurality of first fuel injection holes for injecting fuel into the combustion chamber, and an inner side and an outer side arranged on the inner side and the outer side in the radial direction of the inner cylinder with respect to the first fuel injection hole to supply the air to the combustion chamber An air passage and a second fuel injection hole for injecting fuel into the inner air passage are provided.

  According to this configuration, the air passing through the outer air passage and the fuel injected from the first fuel injection hole are supplied as an air-fuel mixture to the outer peripheral portion of the combustion chamber in the inner cylinder. At the same time, the air passing through the inner air passage and the fuel injected from the second fuel injection hole are supplied to the central portion of the cylinder as an air-fuel mixture. For this reason, the backflow region of the air-fuel mixture in the central portion of the combustion chamber and the outer peripheral portion thereof is formed with good balance, and the flame can be stably held.

  In an embodiment of the present invention, the second fuel injection hole is connected to a fuel passage that supplies fuel to the first fuel injection hole. According to this configuration, the fuel passage configuration is simplified.

  In another embodiment of the present invention, the second fuel injection hole is arranged in the vicinity of the upstream side of the first fuel injection hole in the fuel passage. According to this configuration, it is possible to prevent the flame from flowing backward into the fuel supply device.

  According to the combustor of the present invention, the backflow region of the air-fuel mixture in the combustion chamber is formed in a well-balanced manner, the flame can be stably held, and the flame holding property is excellent.

Embodiments of a combustor for a gas turbine according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing a gas turbine to which a combustor of the present invention is applied. This gas turbine has a compressor 1, a combustor 2 and a turbine 3 as main components. The combustor 2 supplies fuel to the compressed air supplied from the compressor 1 for combustion, and supplies the turbine 3 with high-temperature and high-pressure combustion gas generated thereby. The compressor 1 is connected to the turbine 3 via the rotary shaft 5 and is driven by the turbine 3. The compressor 1 rotationally drives a load 7 such as a generator via a speed reducer 4. An exhaust gas boiler 8 is connected to the exhaust side of the turbine 3, and water supplied from a pipe 9 having a pump 9 a is heat-exchanged to supply steam to the combustor 2. Further, a part of water is supplied to the combustor 2 from the downstream side of the pump 9 a in the pipe 9.

  FIG. 2 is a vertical cross-sectional view of a main part of the combustor 2 according to the embodiment of the present invention. The combustor 2 includes an inner cylinder 10 that forms a combustion chamber C therein, an outer cylinder 11 that covers the outside of the inner cylinder 10, and a fuel injection device 20 that is attached to the top of the inner cylinder 10. ing. The combustion gas G generated in the combustion chamber C flows out in the direction of the arrow and travels toward the turbine 3 (FIG. 1). Between the inner cylinder 10 and the outer cylinder 11, air introduction for introducing the compressed air CA for combustion supplied from the compressor 1 (FIG. 1) in the direction opposite to the outflow direction of the combustion gas G in the inner cylinder 10. A passage 12 is formed. The combustor 2 protrudes substantially outward in the radial direction of the turbine 3 in FIG. 1, and the compressed air CA from the compressor 1 moves the air introduction passage 12 in FIG. 2 to the front end side of the combustor 2. After flowing toward the combustion chamber C, it is sent to the combustion region S near the top of the inner cylinder 10 in the combustion chamber C, where it is mixed with the fuel F injected from the fuel injection device 20, and the mixture is combusted to burn the combustion gas G. And flows out from the base end side of the combustor 2. The fuel F is a gas or a liquid.

  FIG. 3 is an enlarged bottom view of the fuel injection device 20, and FIG. 4 is a longitudinal sectional view of the device 20. As shown in FIG. 4, the fuel injection device 20 includes a first nozzle body 21 and a cylindrical second nozzle body 22 disposed around the first nozzle body 21. The first nozzle body 21 has a nozzle body 21a and a nozzle tip 21b at the tip thereof. The second nozzle body 22 includes a nozzle body 22a, a connecting member 22b at the tip thereof, an end plate 22c at the tip thereof, and a partition member 22d forming an inner peripheral wall of the nozzle body 22a. A fuel passage 24 for the fuel F is formed inside the second nozzle body 22, and a plurality of first fuel injection holes 26 are concentric with the inner cylinder 10 in the end plate 22c as shown in FIG. (6 pieces in FIG. 3) are formed. The fuel F shown in FIG. 4 is introduced into the fuel passage 24 from a nipple 27 provided on the side of the nozzle body 22a of the second nozzle body 22, and is fixed into the combustion chamber C from the first fuel injection hole 26. Injected at a diffusion angle θ1. The fuel passage 24 includes an annular space 24a between the nozzle body 22a and the partition member 22d, and a plurality of communication holes 24b provided in the connecting member 22b at equal intervals in the circumferential direction of the second nozzle body 22 and extending in the axial direction. And an annular lead-out space 24c provided in the end plate 22c.

  An inner air passage 28 and an outer air passage 29 for supplying the compressed air CA from the compressor 1 into the combustion chamber C are provided at the radially inner and outer positions of the inner cylinder 10 with respect to the first fuel injection hole 26. And are formed. In the illustrated embodiment, an annular inner air passage 28 is formed between the first nozzle body 21 and the second nozzle body 22 radially inward of the first fuel injection hole 26, and this is used as the second nozzle. 4 is communicated with the air introduction passage 12 through a plurality of introduction passages 30 penetrating in the radial direction, and the compressed air CA from the air introduction passage 12 is connected to the inside of the introduction passage 30 in FIG. It is configured to be introduced into the air passage 28. In this example, three introduction paths 30 are provided as shown in FIG. 3, and each introduction path 30 extends along the radial surface of the second nozzle body 22 and faces radially inward as shown in FIG. And is inclined so as to approach the tip of the second nozzle body 22.

  An axial swirler 39 composed of fixed vanes for supplying compressed air CA from the air introduction passage 12 into the combustion chamber C as a swirling flow is disposed around the outer periphery of the end plate 22 c of the inner cylinder 10. Thus, the outer air passage 29 is formed. A cylinder cover 31 having a plurality of air introduction holes 31a is provided at the top of the inner cylinder 10 in FIG. 2, and the compressed air CA from the air introduction passage 12 is introduced into the cylinder cover 31 through the air introduction holes 27a. A part of the compressed air CA in the cover 31 passes from the introduction passage 30 in FIG. 4 through the inner air passage 28 into the combustion chamber C, and the remaining compressed air CA is swirled from the axial swirler 39 into the combustion chamber C. To supply each.

  Further, at the lower end portion of the connecting member 22 b of the second nozzle body 22, a plurality of second passages that communicate the fuel passage 24 and the inner air passage 28 in the vicinity of the upstream side of the first fuel injection hole 26 in the fuel passage 24. The fuel injection hole 32 is formed concentrically with the inner cylinder 10. In this example, as shown in FIG. 3, six second fuel injection holes 32 are provided at equal intervals in the circumferential direction, and the circumferential position of every other second fuel injection hole 32 is the aforementioned introduction. It is the same as the road 30. These second fuel injection holes 32 communicate with the lead-out space 24c, a part of the fuel F is supplied from the lead-out space 24c to the inner air passage 28, and the fuel F is compressed air in the inner air passage 28. It is injected at a constant diffusion angle θ2 toward the central portion in the combustion chamber C together with CA.

  A water supply passage 33 is formed in the center of the first nozzle body 21 of the fuel injection device 20 shown in FIG. 2, and a part of the water W passing through the pipe 9 in FIG. 1 is passed through the water supply passage 33 in FIG. The tip 21b is supplied toward the center portion in the combustion chamber C. Further, a steam supply passage 35 is formed in the upper end plate 34 provided at the top of the fuel injection device 20 in FIG. 2, and the steam ST generated in the exhaust gas boiler 8 in FIG. Then, the gas is supplied into the combustion chamber C through the introduction path 30 and the axial swirler 39 of FIG. The combustor 2 may be of a type that does not supply the water W and the steam ST, or a type that supplies only one of the water W and the steam ST.

  In FIG. 2, on the peripheral wall of the inner cylinder 10, combustion air holes 36 for introducing combustion air from the air introduction passage 12 to the combustion area S in the inner cylinder 10, and air downstream of the combustion area S. And a dilution air hole 37 is provided. The fuel injection device 20 is attached to the upper end plate 34 with bolts via an attachment plate 38 fixed thereto.

  Next, the operation of the combustor 2 will be described. Compressed air CA supplied from the compressor 1 in FIG. 1 is supplied into the inner cylinder 10 from the axial swirler 39 via the air introduction passage 12 in FIG. 2, and a part of the compressed air CA is introduced from the introduction passage 30 in FIG. It is supplied into the inner cylinder 10 through the inner air passage 28. On the other hand, the fuel F passes through the fuel passage 24 and is injected from the first and second fuel injection holes 26 and 32 into the combustion chamber C to be mixed with the compressed air CA to become an air-fuel mixture, that is, the top of the combustion chamber C, that is, It is burned in the combustion region S inside the top of the inner cylinder 10.

  At this time, a part of the fuel F passing through the fuel passage 24 is injected into the inner air passage 28 from the second fuel injection hole 32, and is injected into the central portion of the combustion region S together with the compressed air CA passing therethrough. The reverse flow region of the air-fuel mixture formed in this combustion region S is formed with a good balance. That is, the fuel F from both the first and second fuel injection holes 26 and 32 forms a stronger air-fuel mixture reverse flow region S1 at the central portion of the top of the combustion chamber C than the conventional one. And the reverse flow region S2 of the air-fuel mixture formed in the outer periphery of the combustion chamber C around the outer periphery thereof is formed with a good balance in strength. For this reason, the flame is stably held and the flame holding property is excellent. Here, since the second fuel injection hole 32 is formed in communication with the fuel passage 24, the passage configuration is simplified. In addition, since the second fuel injection hole 32 is disposed in the vicinity of the upstream side of the first fuel injection hole 26 in the fuel passage 24, it is possible to prevent the flame from flowing backward into the back of the fuel supply device 20. The

It is a schematic block diagram which shows the gas turbine to which the combustor of this invention is applied. It is a longitudinal cross-sectional view of the principal part of the combustor concerning one Embodiment of this invention. It is a bottom view which expands and shows the fuel-injection apparatus of a combustor. It is a longitudinal cross-sectional view of the fuel injection device.

Explanation of symbols

10 Inner cylinder 11 Outer cylinder 12 Air introduction passage 24 Fuel passage 26 First fuel injection hole 28 Inner air passage 29 Outer air passage 32 Second fuel injection hole C Combustion chamber CA Air G Combustion gas F Fuel

Claims (3)

An inner cylinder that forms a combustion chamber inside and an outer cylinder that covers the outer side of the inner cylinder, and between the inner cylinder and the outer cylinder, combustion of air from the compressor toward the turbine from the inner cylinder A combustor having an air introduction passage for introducing the gas in the direction opposite to the gas outflow direction,
A plurality of first fuel injection holes arranged concentrically with the inner cylinder at the top of the inner cylinder and injecting fuel into the combustion chamber;
Inner and outer air passages disposed on the inner and outer sides in the radial direction of the inner cylinder with respect to the first fuel injection hole and supplying the air to the combustion chamber;
A gas turbine combustor including a second fuel injection hole for injecting fuel into the inner air passage.   The combustor of a gas turbine according to claim 1, wherein the second fuel injection hole is connected to a fuel passage that supplies fuel to the first fuel injection hole. The gas turbine combustor according to claim 2, wherein the second fuel injection hole is disposed in the vicinity of the upstream side of the first fuel injection hole in the fuel passage.

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