JPH08135969A - Air flow rate regulator for gas turbine combustor - Google Patents

Abstract

PURPOSE: To provide a gas turbine combustor, permitting reduction of NOx, by a method wherein combustion air is supplied into a premixing device without disturbing the flow of combustion air in the premixing device to retain the mixing ratio of fuel to air in combustion zone so as to be uniform regardless of the flow rate of combustion air. CONSTITUTION: A flow regulating ring 18, having lattice type slits for dividing the flow passage of air which flows into a premixing device 15, is arranged at the combustion air intake unit 19 of the premixing device 15. A lid body, covering the flow regulating ring 18, or an air flow rate regulating valve 20, having a cylindrical shape and provided with lattice type slits, is arranged at the outer periphery of the flow regulating ring 18. The air flow rate regulating valve 20 is moved into the axial direction of a gas turbine combustor whereby the opening area of the flow regulating ring 18 is regulated and the flow rate of air, which flows into the premixing device 15, can be controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air flow controller for a gas turbine combustor having a premixer.

[0002]

BACKGROUND ART Exhaust gas discharged from a gas turbine combustor contains gases such as NOx, CO, and HC that cause air pollution, but these gases are subject to strict emission regulations. There is. At present, as a method of reducing NOx, by distributing fuel in multiple stages to reduce the combustion load per stage or to perform lean combustion,
The method of suppressing the generation of a partial high temperature region has become the mainstream.

In the case of a gas turbine combustor, due to structural restrictions, diffusion combustion in which fuel and air separately flow into the combustor from the upstream side of the combustor and burns, and fuel and air are mixed in advance. Then, a so-called two-stage combustion system with premixed combustion in which combustion is performed on the downstream side is adopted. In recent years, even lower N
In order to achieve Ox, the combustion ratio of premixed combustion tends to increase in the high load region.

Further, in a low NOx combustor of a gas turbine, in order to prevent unstable combustion, it is possible to adjust the flow rates of fuel and air so that the ratio of the fuel flow rate to the air flow rate becomes a set value. It is necessary and the flow rate of fuel is normally adjusted by a control valve or the like according to a change in load.

A method of adjusting the flow rate of combustion air flowing into the premixer is disclosed in Japanese Patent Laid-Open No. 61-195214. Therefore, this method will be described with reference to FIG. FIG. 4 is an explanatory view of a flow rate control valve for inflow air into the premixer of this known example.

That is, at the opening of the combustion air intake portion 19 of the premixer 15 in which the second-stage fuel nozzle 16 is installed, an air flow rate control valve 20 which is a lid for covering the opening is arranged. In this method, the air flow rate control valve 20 is moved so that the area of the opening changes, and the air flow rate flowing into the premixer 15 is adjusted. This makes it possible to control the ratio of the fuel flow rate to the air flow rate regardless of load changes.
It is designed to prevent the discharge of unburned fuel.

Further, when the air flow control valve is moved as described above, the change in the air flow caused by the movement is made insensitive to
A method for properly distributing the air flow rate is disclosed in JP-A-62-842.
No. 27 publication.

[0008]

In order to reduce NOx in a gas turbine combustor, a so-called premixed combustion ratio, which is obtained by premixing fuel and air, that is, a premixed combustion combustion ratio is increased. Doing is a very effective means. Also, low N in the entire load range of the gas turbine.
In order to realize Ox conversion, it is necessary to control the ratio between the fuel flow rate and the air flow rate, and for that purpose, the air flow rate supplied to the premixer as shown in the above-mentioned known example is adjusted. Method becomes essential.

When performing premixed combustion, the mixing ratio of fuel and air in the premixed gas supplied to the combustion region is
Being temporally constant and spatially uniform,
It is known to be advantageous in reducing NOx.

Further, in order to keep the mixing ratio of fuel and air uniform, it is preferable to increase the mixing distance. Therefore, in the above-mentioned known example, the fuel supply nozzle is arranged at the upstream position of the premixer. Then, the mixing distance to the combustion region is increased.

However, in the case of the above-mentioned known example, the fuel supply nozzle is installed at the curved portion of the premixer flow path, and this position is a region where the flow of combustion air is disturbed. Further, when the opening degree of the combustion air intake portion of the premixer is small, a large vortex is formed at the downstream position of the air flow rate control valve, which further disturbs the flow.

As described above, when the flow of the combustion air in the premixer is disturbed, it becomes impossible to keep the mixing ratio of the fuel and air uniform, and a fire enters the premixer. There is a risk of fire and extinguishing.

The present invention has been made in view of such circumstances, and the combustion air supplied to the premixer is disturbed regardless of the air flow rate and the flow of the combustion air in the premixer is disturbed. Instead, it is supplied into the premixer to maintain a uniform mixing ratio of fuel and air in the combustion region, thereby reducing NOx.
It is an object of the present invention to provide a gas turbine combustor that can be converted into a gas.

[0014]

The above object can be achieved as follows.

(1) A cylindrical diffusion combustion section liner having an opening for introducing air on its peripheral wall, and a plurality of fuels which are located at the head of the diffusion combustion section liner and which supply fuel to the inside of the diffusion combustion section liner. A premixer having a diffusion combustion chamber formed of a fuel nozzle, a plurality of fuel nozzles and a combustion air intake section at the head of an annular flow path formed on the outer peripheral side of the diffusion combustion section liner, and a premixer And a premixing combustion chamber for performing premixed combustion by the premixer, and is located on the outer peripheral side of the combustion air intake section of the premixer and has an opening of the combustion air intake section. In an air flow controller for a gas turbine combustor equipped with an annular lid that moves so that the area changes, a plurality of air turbines arranged in the axial direction of the gas turbine combustor are provided at the combustion air intake section of the premixer. An annular straightening plate with an opening is installed. To have it.

(2) In (1), each of the lid and the current plate is provided with a plurality of slits arranged in the axial direction of the gas turbine combustor.

(3) In (1), a plurality of lattice-shaped slits arranged in the axial direction of the gas turbine combustor are provided on each of the lid and the current plate.

(4) In (1), (2) or (3), the straightening vanes are provided with guide vanes extending toward the downstream side of the straightening vanes in the air flow direction.

[0019]

In the present invention, in the air flow controller of the gas turbine combustor, the combustion air intake portion of the premixer is
(1) An annular flow plate having a plurality of openings arranged in the axial direction of the gas turbine combustor, and (2) an annular lid body having a plurality of slits arranged in the axial direction of the gas turbine combustor. , And an annular current plate, or (3) an annular lid body and an annular current plate that respectively have a plurality of lattice-shaped slits arranged in the axial direction of the gas turbine combustor.

For this reason, the size of the vortex formed on the downstream side of each combustion air intake section becomes smaller than that on the flow path of the premixer, so that it is arranged on the downstream side of the combustion air intake section. At the position of the fuel supply nozzle, a flow field is formed by many small vortices. Therefore, the mixing ratio of fuel and air in the combustion region can be kept uniform,
Low NOx can be achieved.

Further, in the above (1), (2) or (3), since the straightening vanes are provided on the straightening vanes toward the downstream side in the air flow direction of the straightening vanes, the straightening action of the combustion air is improved. The effect is improved and the stability of the flame is increased.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram of a gas turbine plant equipped with an air flow controller according to this embodiment, and FIG. 2 is an enlarged view of a main part of FIG.

The feature of this embodiment lies in the air flow rate controller. First, an outline of a gas turbine plant equipped with the air flow rate controller of this embodiment will be described.

As shown in FIG. 1, the gas turbine plant is mainly composed of a gas turbine combustor 1 and a compressor 3 which is connected to a gas turbine 2 to obtain compressed air for combustion and cooling.

The compressed air discharged from the compressor 3 is guided to the gas turbine combustor 1 and burned together with the fuel in the combustion chamber 5 formed inside the combustor liner 4 of the gas turbine combustor 1 and generated at that time. The high-temperature and high-pressure combustion gas is injected into the gas turbine 2 through the transition piece 7 and drives the gas turbine 2. Then, it is configured to generate electric power by a generator (not shown) connected to the gas turbine 2.

The main structure of the gas turbine combustor 1 is composed of a combustor liner 4 for producing combustion gas, a fuel supply system and an air supply system, which are sealed by an outer cylinder 8 and an end cover 9. It is installed inside 10.

A diffusion combustion section 12 is provided on the upstream side of the combustor liner 4. That is, the diffusion combustion section liner 11 having a smaller diameter than that on the downstream side is provided, and the first stage fuel nozzle 13 for diffusion combustion and the inner cylinder 14 are installed in the diffusion combustion section liner 11, and the diffusion combustion section 12 is provided. Has been formed. Then, the diffusion combustion is performed in the diffusion combustion liner 11 by the fuel supplied from the first stage fuel nozzle 13.

A premixer 15 is installed on the outer circumferential side of the diffusion combustion liner 11 in the radial direction, and a second-stage fuel nozzle 16 for premix combustion is provided upstream of the premixer 15. The compressed air discharged from the compressor 3 is transferred to the outer cylinder 8 and the combustor liner 4.
Through the air flow path 17 formed by the premixer 15
The fuel that has flowed into the interior of the tank and is injected from the second-stage fuel nozzle 16 is mixed with the fuel in the premixer 15 to form a premixed gas.

The premixed gas is jetted into the combustion chamber 5 through the premixing combustion section 6, and heat energy is generated by the diffusion combustion in the diffusion combustion section liner 11, and the premixed combustion is performed in the combustion chamber 5.

Next, the air flow controller of this embodiment will be described.

In this embodiment, in the structure of such a gas turbine plant, the combustion air intake portion 19 of the premixer 15 has a grid-like shape for dividing the flow path of the air supplied to the premixer 15. This is a case where the rectifying ring 18 having slits is arranged, and the lid body covering the rectifying ring 18 on the outer peripheral side thereof, that is, the air flow rate control valve 20 having cylindrical and lattice-shaped slits is installed.

That is, by moving the air flow rate control valve 20 in the axial direction of the gas turbine combustor 1 (hereinafter simply referred to as the axial direction), the opening area of the rectifying ring 18 arranged in the combustion air intake portion 19 is increased. Is adjusted to control the flow rate of air supplied to the premixer 15.

The operation of the rectifying ring 18 and the air flow rate adjusting valve 20 both having the lattice-like slits thus configured will be described with reference to FIG. That is, FIG.
FIG. 4 is an enlarged view of a main part of this embodiment, in which a rectifying ring 18 is arranged in a combustion air intake part 19. The total area of the openings of the rectifying ring 18 was determined by the combustion performance of the premixer 15, that is, the design flow velocity at the outlet of the premixer 15.

In this embodiment, the slit portion, that is, the opening portion 18a and the closing portion 18b of the rectifying ring 18 have the same axial length and are arranged so as to cover the rectifying ring 18. The axial lengths of the slit portion, that is, the opening portion 20a and the closing portion 20b of the valve 20 are configured to be equal to those of the rectifying ring 18. In this way, the total area of the openings 20a of the air flow control valve 20 and the openings 18a of the rectifying ring 18 are
And the total area of

FIG. 2A shows a state in which the opening 18a of the rectifying ring 18 is closed, and FIG.
2 shows a state in which the air flow rate control valve 20 has moved in the axial direction from the state of FIG. 2A, and the opening 18a has been largely opened.

Normally, when the flow rate of air flowing into the premixer 15 is small, that is, when the opening of the opening 18a is small, a strong reverse flow region is generated on the downstream side of the air flow control valve 20, and this reverse flow causes premixing. It is possible to disturb the flow in the vessel 15.

However, in this embodiment, as shown in FIG. 2B, the opening 18a of the rectifying ring 18 is divided into equal parts in the axial direction. Therefore, the air flow control valve 20
The backflow region generated on the downstream side of the
The flow of combustion air inside is not disturbed.

Further, since the air is uniformly supplied to the combustion air intake section 19 from the flow direction regardless of the air flow rate, the air flow rate distribution in the flow direction becomes uniform. Furthermore,
Since the combustion air intake portion 19 has an enlarged flow path, a rectifying function works and air flow turbulence is reduced. That is, since it becomes possible to supply a premixed gas that is constant in time and spatially uniform to the premixed combustion region, a low N
Ox conversion can be achieved.

In this embodiment, the opening 18 of the rectifying ring 18 is used.
a and the shape of the opening 20a of the air flow rate control valve 20,
Although the holes have a lattice shape, that is, a rectangular shape, even if the shape of the opening is circular, the same effect as that of the present embodiment can be obtained.

Further, normally, the axial control range of the air flow rate control valve is the axial length of the opening of the combustion air intake portion. It is the axial length of the opening 18a. This is also the axial length of the opening 20a of the air flow rate control valve 20, but since the control range can be shortened in this way, it is also advantageous in terms of reliability.

Another embodiment of the present invention will be described with reference to FIG. FIG. 3 is an explanatory view of a main part of a gas turbine plant provided with the air flow rate controller of the present embodiment.
The main components such as the second stage fuel nozzle 16 and the air flow rate control valve 20 are the same as those in the above-described embodiment.

The feature of the present embodiment is that a guide vane 21 manufactured according to the flow path shape of the premixer 15 is attached to the closing portion 18b of the rectifying ring 18. This allows
As compared with the above-mentioned embodiment, the rectifying action of the combustion air was further improved, and the flame stability could be increased.

[0043]

According to the present invention, the combustion air supplied to the premixer is supplied to the premixer regardless of the air flow rate and without disturbing the flow of the combustion air in the premixer. Therefore, it becomes possible to supply the premixed gas that is temporally constant and spatially uniform to the combustion region at the outlet of the premixer, and it is possible to reduce the NOx.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an explanatory diagram of another embodiment of the present invention.

FIG. 4 is an explanatory diagram of a conventional combustion air flow rate regulator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gas turbine combustor, 2 ... Gas turbine, 3 ... Compressor, 4 ... Combustor liner, 5 ... Combustion chamber, 6 ... Premix combustion part, 7 ... Transition piece, 8 ... Outer cylinder, 9 ... End cover, 10 ... Pressure vessel, 11 ... Diffusion combustion liner, 1
2 ... Diffusion combustion part, 13 ... First stage fuel nozzle, 14 ... Inner cylinder, 15 ... Premixer, 16 ... Second stage fuel nozzle, 17 ...
Air flow path, 18 ... straightening ring, 18a ... opening, 18b
... Closing part, 19 ... Combustion air intake part, 20 ... Air flow control valve, 20a ... Opening part, 20b ... Closing part, 21 ... Guide vane.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Inoue, 502 Jinritsucho, Tsuchiura-shi, Ibaraki Hiritsu Seisakusho Co., Ltd. (72) Inventor Shigeyuki Akatsu 502, Jinritsucho, Tsuchiura-shi, Ibaraki Hiritsu Seisakusho, Ltd. In the Mechanical Research Laboratory (72) Inventor Tomoki Kogana, 502 Kintatecho, Tsuchiura City, Ibaraki Prefecture

Claims (4)

[Claims] 1. A cylindrical diffusion combustion section liner having a peripheral wall provided with an opening for introducing air, and a plurality of fuel supply units located at the head of the diffusion combustion section liner for supplying fuel to the inside of the diffusion combustion section liner. And a premixer having a plurality of fuel nozzles and a combustion air intake section at the head of an annular flow path formed on the outer peripheral side of the diffusion combustion section liner, It is located on the downstream side of the premixer and is provided with a premixing combustion chamber for performing premixed combustion by the premixer, and is located on the outer peripheral side of the combustion air intake part of the premixer, In an air flow controller of a gas turbine combustor having an annular lid body that moves so that the opening area of the intake air intake portion changes, the gas turbine combustor is provided in the combustion air intake portion of the premixer. Multiple elements arranged in the axial direction of An air flow controller for a gas turbine combustor, which is provided with an annular flow straightening plate having a number of openings. 2. Each of the lid and the current plate,
The air flow controller for a gas turbine combustor according to claim 1, wherein a plurality of slits arranged in the axial direction of the gas turbine combustor are provided. 3. Each of the lid and the current plate,
The air flow controller for a gas turbine combustor according to claim 1, wherein a plurality of lattice-shaped slits arranged in the axial direction of the gas turbine combustor are provided. 4. The air flow rate regulator for a gas turbine combustor according to claim 1, 2 or 3, wherein the flow straightening plate is provided with guide vanes extending toward a downstream side of the flow straightening plate in an air flow direction.