JPH1089691A - Combustor for gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further reduce NOx by making premix gas by a main burner uniform. SOLUTION: A main burner 12 is mounted on an annular integrated evaporation ring 16, and a fuel injected from the main burner 12 is spreaded also peripherally to make fuel distribution uniform and hence ensure further reduction of NOx. Further, a pilot burner 11 is mounted on a base end of a lean premixing pilot chamber 14 on the tip end of which burner a torch burner 33 is mounted. Hereby, also the fuel from the pilot burner 11 is previously mixed with air into a lean state for combustion to reduce NOx from the pilot burner 11. An igniting diffusion combustion torch burner 33 is separately provided to ensure ignitability and safety of combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a combustor for a gas turbine, and more particularly to an improvement in a NOx (nitrogen oxide) generated by combustion by a main burner.

[0002]

2. Description of the Related Art In a gas turbine used for power generation or the like, it is necessary to comply with environmental regulations, one of which is regulation of exhaust NOx.

[0003] Conventionally, exhaust gas denitration has been performed to cope with exhaust NOx, and water and steam have been injected into the combustor.

[0004] However, such a method for reducing exhaust NOx requires special equipment for this purpose, which requires equipment costs and also maintenance costs.

In view of this, it has been attempted to reduce NOx by controlling the combustion of a combustor for a gas turbine. For example, as shown in FIG. 5, a central portion of a liner 2 of a combustor 1 for a gas turbine is used. A pilot burner 3 for diffusion combustion is disposed at a position, and a plurality of main burners 5 are disposed around an evaporating pipe 4 for lean premix combustion. The pilot burner 3 holds a flame for ignition. In the main burner 5, the evaporating pipe 4 sufficiently evaporates the fuel and mixes the air to reduce NOx by lean combustion.

[0006]

However, in such a combustor 1 for a gas turbine, although the combustion by the main burner 5 is made to be a lean premixed combustion, the NOx can be reduced, but the evaporating pipe 4 is not used. Looking at the fuel distribution in the circumferential direction at the outlet portion of FIG. 2, as shown in FIG. 2 (b), the premixed gas has shading in the portion where the main burner 5 is arranged and the portion between the portions, and the There is a problem that the generation of NOx cannot be suppressed in some parts.

When the amount of NOx generated from the main burner is reduced, the amount of NOx generated by the diffusion combustion of the pilot burner 3 may become a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and aims to provide a combustor for a gas turbine which can make the premixed air by a main burner uniform and further reduce NOx. Is what you do.

Another object of the present invention is to provide a gas turbine combustor capable of reducing NOx from a pilot burner.

[0010]

According to a first aspect of the present invention, there is provided a gas turbine combustor.
In a combustor for a gas turbine having a pilot burner and a plurality of main burners, the main burner is provided in an evaporating ring formed integrally in a ring shape.

According to this combustor for a gas turbine, the main burner is mounted on the evaporating ring formed in an annular shape, and the fuel injected from the main burner also spreads in the circumferential direction. And NOx is further reduced.

According to a second aspect of the present invention, in the gas turbine combustor according to the first aspect of the present invention, the evaporating ring formed integrally with the annular partition partitions an adjacent main burner. And a partition plate protruding to an intermediate portion of the evaporating ring.

According to this gas turbine combustor, a partition plate protruding to the intermediate portion of the evaporating ring is provided between the main burners adjacent to the evaporating ring formed in an annular shape. The fuel and the air injected from the main burner are mixed in advance in the portion where the partition plate is located, and further spread in the circumferential direction in front of the partition plate so that the fuel distribution is made more uniform to reduce NOx. I have.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the gas turbine combustor for lean premixing of the pilot burner disposed at the center of the main burner is provided. The present invention is characterized in that a torch burner for holding an ignition flame is provided at a front end of the lean premixing chamber.

According to this gas turbine combustor, the fuel distribution in the circumferential direction of the main burner is made uniform, the pilot burner is mounted on the base end of the lean premixing chamber, and the torch burner is mounted on the front end thereof. The fuel from the pilot burner is also premixed with air and burned in a lean state to reduce NOx, and a separate torch burner for diffusion combustion for ignition is provided to improve ignitability and combustion. Stability is ensured, and total emission NOx is further reduced.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of a combustor for a gas turbine according to the present invention, in which (a) is a central longitudinal sectional view, and (b) is a side view of a left half.

The gas turbine combustor 10 includes a pilot burner 11 and a plurality of main burners 12. The pilot burner 11 is provided at the center of the end of the liner 13 via a pilot chamber 14. ,
Air corresponding to the stoichiometric ratio is supplied from the swirler 15 to maintain a stable flame due to diffusion combustion and to reliably ignite the main burner 12.

On the other hand, the main burners 12 are arranged at equal intervals around the pilot burner 11. These main burners 12 are formed integrally with the end of the liner 13 in an annular shape and are used for a double tubular lean premix combustion. Attached via an evaporating ring 16, a swirler 17 is provided around each main burner 12 so as to supply air necessary for forming a lean premix.

In the gas turbine combustor 10 configured as described above, the fuel injected from each of the main burners 12 is injected into a space connected to one of the annular evaporating rings 16. Compared to a case where fuel is injected into a tubular evaporator tube independent for each main burner, the fuel is more likely to spread in the circumferential direction and is uniformly mixed with air.

Therefore, looking at the fuel distribution on the outlet side of each main burner 12, as shown in FIG. 2 (a), the portion where the main burner 12 is disposed and the main burner 12
The change in the concentration of the premixed gas is slight in the portion between and a uniform premixed gas is produced.

As a result, the amount of NOx generated from the region of the premixed gas having a high concentration is suppressed, the combustion can be performed in a leaner premixed state, and the amount of generated NOx can be reduced.

Further, since the premixed gas is continuously formed in the circumferential direction from the annularly connected evaporating rings 16, the ignitability of the pilot burner 11 by the flame is also improved, and a stable lean premixed combustion state is obtained. Can be.

Next, a gas turbine combustor according to another embodiment of the present invention will be described with reference to FIG.

In the combustor 20 for a gas turbine, a partition plate 21 is provided between the main burners 12 of the annularly integrated evaporating ring 16 to which the main burner 12 is attached, and protrudes to the middle of the evaporating ring 16.

The other components are the same as those of the gas turbine combustor 10 described above, and therefore, the same portions are denoted by the same reference numerals and description thereof is omitted.

The evaporating ring 16 provided with such a partition plate 21
Then, the fuel injected from the main burner 12 first
After being preliminarily mixed with air by the high fuel injection pressure in the space partitioned by the partition plates 21 on both sides, these premixed air spread in the circumferential direction in front of the partition plate 21 and are mixed more uniformly, and Can be eliminated.

As a result, the amount of NOx generated from the region of the premixed gas having a high concentration is suppressed, the combustion can be performed in a more uniform and lean premixed state, and the amount of generated NOx can be reduced.

Next, a gas turbine combustor according to another embodiment of the present invention will be described with reference to FIG.

In the gas turbine combustor 30, in addition to the gas turbine combustors 10 and 20 described in the above two embodiments, the amount of NOx generated by the main burner 12 can be suppressed, and the pilot burner 11
This also suppresses the generation of NOx.

For this reason, in the combustor 30 for a gas turbine, the pilot burner 11 disposed at the center of the liner 13 is provided with a pilot chamber 14 provided in the liner 13 and an evaporating pipe 31 attached to an end thereof. It is provided through. A swirler 15 for taking in air is provided around the pilot burner 11, and a swirler 32 for taking in air is also provided in the pilot chamber 14 at the tip of the evaporating tube 31.

Further, a torch burner 33 is attached to the base end of the pilot chamber 14.
An igniter 34 is mounted on the side of the pilot chamber 14 close to the igniter 3.

In the gas turbine combustor 30, a control device (not shown) is provided for controlling the amount of fuel supplied to the pilot burner 11. At the time of ignition, first, the fuel supplied from the torch burner 33 is supplied to the igniter 34 by the igniter 34. The combustion state by the diffusion flame is ignited and the fuel and the air from the pilot burner 11 and the swirler 15 are controlled in such a state that the diffusion combustion occurs in a state close to the stoichiometric ratio by the pilot burner. When the fuel is supplied to the main burner 12 in order to put the gas turbine into a load state from the combustion state using only the fuel 11, the fuel supply amount is reduced in the pilot burner 11, and the evaporating pipe 31 and the pilot chamber 14 are discharged by the flame. Lean fuel that forms a pre-fuel mixture that is leaner than the stoichiometric fuel-air mixture without being present With a coupling chamber, the Tochibana 34 controls to supply the fuel to the diffusion combustion to form a mixture close to the stoichiometric ratio for retaining the flame.

Further, similarly to the gas turbine combustors 10 and 20 of the above embodiments, the control unit controls the amount of fuel supplied to the plurality of main burners 12 and, for example, according to the load applied to the gas turbine. Staging control for controlling the number of main burners 12 to be used is performed, and the ignition by the flame from the pilot burner 11 is ensured and the lean premixed combustion state is always maintained, so that the generation of NOx is suppressed to a low level and the stable combustion state is maintained. To ensure that

The other components are the same as those of the gas turbine combustors 10 and 20 already described, so that the same components are denoted by the same reference numerals and description thereof is omitted.

Therefore, in the combustor 30 for a gas turbine, in a state where combustion is caused by the fuel supplied from the main burner 12, the evaporating ring 16 is
A uniform premixed gas is formed in the circumferential direction of the fuel and the air without forming a flame in the inside, a lean premixed combustion occurs, the generation of NOx is suppressed, and the evaporating pipe 31 and the pilot chamber 14 are also provided in the pilot burner 11. However, a premixed mixture of fuel and air is formed without forming a flame, lean premixed combustion occurs, NOx is suppressed, and the amount of NOx generated in the entire combustor 30 for the gas turbine is further reduced. it can.

On the other hand, by making the combustion in the pilot burner 11 a lean premixed combustion, it becomes difficult to secure the stability and ignitability of the flame, which are functions necessary for the pilot burner 11, Since the torch burner 33 is provided in the chamber 14 to secure a stable flame due to diffusion combustion, it is possible to secure stable combustion in the pilot burner 11 using the small flame by the torch burner 33 as a fire.

[0037]

According to the gas turbine combustor according to the first aspect of the present invention, the main burner is attached to the evaporating ring integrally formed as described above. As a result, the fuel injected from the main burner can also be spread in the circumferential direction to make the fuel distribution uniform, and by suppressing the generation of NOx from the dense portion due to the uneven fuel distribution, the NOx
Can be reduced.

Further, even if the fuel distribution is made uniform in a conventional combustor having an independent evaporating tube for each main burner, the distribution in the circumferential direction is not maintained because the premixed gas at the outlet of the evaporating tube is discontinuous. Although there was a limit to elimination, in this gas turbine combustor, the premixed gas from each main burner had circumferential continuity and uniformity. An improved and stable lean premixed combustion state can be ensured, and NOx can be reduced.

According to the gas turbine combustor according to the second aspect of the present invention, the partition plate protruding to the intermediate portion of the evaporating ring between the main burners adjacent to the evaporating ring formed in an annular shape is provided. Because it is provided, the fuel and air injected from the main burner are mixed in advance in the portion where the partition plate of the evaporating ring is present, and furthermore, spread in the circumferential direction in front of the partition plate to further uniform the fuel distribution. Thus, NOx can be reduced.

Furthermore, according to the gas turbine combustor according to the third aspect of the present invention, the fuel distribution in the circumferential direction of the main burner is made uniform, and the pilot burner is connected to the base end of the lean premixing chamber. The torch burner is attached to the tip of the burner, so that the fuel from the pilot burner can be mixed with air in advance and burned in a lean state, so that NOx from the pilot burner can be reduced and diffusion for ignition can be performed. By providing a separate torch burner for combustion, ignitability and combustion stability can be ensured, and the total emission NOx can be further reduced.

[Brief description of the drawings]

FIG. 1 shows a gas turbine combustor according to an embodiment of the present invention, in which (a) is a longitudinal sectional view at the center and (b) is a side view of a left half.

FIG. 2 is an explanatory diagram showing a fuel distribution in a circumferential direction of a main burner according to an embodiment of the combustor for a gas turbine of the present invention, as compared with a conventional fuel burner.

3A and 3B show another embodiment of the gas turbine combustor of the present invention, in which FIG. 3A is a longitudinal sectional view at the center and FIG. 3B is a side view of the left half.

FIG. 4 shows a further embodiment of the combustor for a gas turbine according to the present invention, in which (a) is a central longitudinal sectional view,
(B) is a side view of the left half.

FIG. 5 shows a conventional gas turbine combustor.
(A) is a center longitudinal cross-sectional view, (b) is a side view of the left half.

[Explanation of symbols]

 Reference Signs List 10 combustor for gas turbine 11 pilot burner 12 main burner 13 liner 14 pilot chamber 15 swirler 16 evaporator ring 17 swirler 20 combustor for gas turbine 21 partition plate 30 combustor for gas turbine 31 evaporator tube 32 swirler 33 torch burner 34 Igniter

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F23R 3/28 F23R 3/28 D 3/34 3/34

Claims (3)

[Claims] 1. A gas turbine combustor having a pilot burner and a plurality of main burners, wherein the main burner is provided in an evaporating ring integrally formed in a ring shape. . 2. The evaporating ring formed integrally with the annular body is provided with a partition plate that partitions between an adjacent main burner and protrudes to an intermediate portion of the evaporating ring. Combustors for gas turbines. 3. A pilot burner disposed at the center of the main burner is provided via a lean premixing chamber, and a torch burner for holding an ignition flame is provided at a front end of the lean premixing chamber. The combustor for a gas turbine according to claim 1 or 2, wherein: