JPH0814562A - Combustion equipment for gas turbine - Google Patents

Abstract

PURPOSE:To diminish the quantity of nitrogen oxide produced, by a construction wherein a lobe mixer dividing inner and outer flows in a plurality in the circumferential direction and mixing them is provided in a pilot chamber and pilot combustion gas and unburnt gas of main fuel are guided inward and outward in a state of being divided in a plurality in the circumferential direction and are mixed. CONSTITUTION:In a main combustion mode, fuel is sent into a main fuel jetting means 34 from a main fuel supply pipe 35 and jetted in an atomized state and also it is mixed with air sent into a main stage 33 and is sent out onto the downstream side. It is guided to be in a state of being narrowed inward as it flows toward the downstream side, in a part in the vicinity of a lobe mixer 40. In the lobe mixer 40, a combustion flow from a pilot stage 26 is divided in a plurality in the circumferential direction and guided to be in a state of being expanded outward as it flows toward the downstream side, on the basis of the shape of this mixer. According to this constitution, the inner and outer flows are put in a state of intersecting each other and mixed effectively and stable combustion is produced in the whole area inside a combustor liner 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus for a gas turbine, and more particularly to improving flame holding performance when the production of nitrogen oxides during combustion is reduced.

[0002]

2. Description of the Related Art A combustion apparatus for a gas turbine is required to reduce the amount of nitrogen oxides in the combustion gas.

As a method of reducing the amount of nitrogen oxides in the combustion gas, a technique is used in which a fuel diluted with a large amount of air and vaporized is burned (by premixing and prevaporizing).

[0004]

In such a gas turbine combustion apparatus, the fuel injected from the pilot fuel injection valve of the pilot combustor is burned and the diluted unburned gas is ignited efficiently. It is necessary to burn, but based on the fact that the unburned gas is diluted, the ignition of the diluted lean unburned gas due to the combustion flame of the pilot combustor and the continuous combustion are likely to become unstable. Challenges remain.

The present invention has been made in view of these problems. In addition to reducing the amount of nitrogen oxides produced during combustion, the present invention has made unburned in a lean state of the main fuel due to the combustion flame of the pilot combustor. Assures ignition of gas,
It is intended to improve flame holding performance during overall combustion.

[0006]

A pilot combustor for burning fuel injected from a pilot fuel injection valve inside a pilot chamber, and a premixer arranged concentrically around the pilot combustor. As a combustion apparatus for a gas turbine having, a premixer forms a ring-shaped main stage around a pilot chamber and extends to a downstream side of the premixing pre-evaporation pipe, and is arranged upstream of the main stage to distribute fuel into an air stream. A main fuel injection means for injecting, at the downstream end of the pilot chamber, the pilot combustion gas is divided into a plurality of parts in the circumferential direction and guided to the outside, and the mixed flow of the main stage is divided into a plurality of parts in the circumferential direction to the inside. A configuration including a lobe mixer for inducing and mixing is adopted.

[0007]

The fuel injected from the pilot fuel injection valve is combusted inside the pilot chamber and sent out in the pilot chamber in the downstream direction. At the lobe mixer, the pilot combustion gas is divided into a plurality of parts. , It is guided to the state where it spreads outward as it goes downstream. The fuel injected from the main fuel injection means is diluted and evaporated by mixing with air, and is sent to the downstream inside the premixing pre-evaporating pipe. It is guided to a narrowed state. By alternately intersecting the internal and external flows, the two fluids are mixed, the combustion flame of the pilot combustor ignites the unburned gas, and vortices are formed at the intersections of the two fluids. By staying, the combustion flame inside the pilot chamber is guided to the place where the fluid stays, and flame holding is performed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a gas turbine combustion apparatus according to the present invention will be described below with reference to FIGS.

As shown in FIGS. 1 to 3, inside a casing 1 of a gas turbine combustion apparatus, there is a pilot combustor 2 for centrally performing pilot combustion, and a periphery of the pilot combustor 2. Is provided with a premixer 3 arranged concentrically with each other, and a combustor liner 4 arranged downstream thereof.

The pilot combustor 2 is connected to a pilot fuel pipe 21 of a pilot fuel supply system to inject pilot fuel, and a pilot fuel injection valve 22, and is connected downstream of the pilot fuel injection valve 22 and ejected. Chamber 23 for burning the burned fuel
And an intake port 24 for taking in a required amount of air into the pilot chamber 23 while swirling, and a spark plug 25 for penetrating fuel jetted in a side portion of the pilot chamber 23 and the like. , A pilot stage 26 for burning pilot fuel.

The premixer 3 is arranged around the pilot chamber 23 of the pilot combustor 2 at a radial interval and extends to the downstream side, and a premixing pre-evaporation pipe 31 is provided. Sleeve 32 which is arranged at a space inside and surrounds the pilot fuel injection valve 22.
And a main stage 33 formed in an annular shape between the premix pre-evaporation pipe 31 and the isolation sleeve 32 for performing pre-mix pre-evaporation, and an air flow from a plurality of circumferentially opened jet holes arranged upstream of the main stage 33. A main fuel injection means 34 such as a fuel spray ring for injecting fuel into the inside, and a main fuel supply pipe 35 of a main fuel supply system which is connected to the main fuel injection means (fuel spray ring) 34 and supplies the main fuel. To have.

At the downstream end of the pilot chamber 23, as shown in FIGS. 1 and 2, a lobe mixer 40.
Are placed together. The lobe mixer 40 has a corrugated side wall continuous in the circumferential direction, and is set so that the corrugation gradually increases toward the downstream side, and the corrugation is formed in a state of protruding both inward and outward.

When the ignition mode is selected in the gas turbine combustor having the above-described structure, the fuel is supplied only to the pilot combustor 2 to burn mainly in the pilot chamber 23. Is done. That is, the fuel required for ignition is sent from the pilot fuel pipe 21 to the pilot fuel injection valve 22 to be ejected in the form of spray, and the pilot stage 2
By operating the spark plug 25 with the fuel concentration of 6 increased, the pilot fuel is ignited to generate the pilot flame Fp, and the combustion state is continued.

Next, when the main combustion mode is selected, the fuel required for continuous combustion is sent from the main fuel supply pipe 35 to the main fuel injection means 34 to be ejected in the form of spray, and also sent to the main stage 33. Dilution and evaporation are promoted by mixing with air to be sent to the downstream side, but in the vicinity of the lobe mixer 40, as shown by the broken line arrow in FIG. It

In the lobe mixer 40, the combustion flow (pilot flame Fp) from the pilot stage 26 is divided into a plurality of portions in the circumferential direction based on the shape thereof, and the lobe mixer 40 is provided with a downstream portion as shown by a solid arrow in FIG. As you go, you will be guided to a state where it spreads outward.

Therefore, these internal and external flows alternately cross each other, the two fluids are mixed, and the pilot flame Fp ignites the unburned gas. As shown in FIG. The main combustion flame Fm is formed in the interior of the combustion chamber, and the combustion spreads throughout the interior of the combustor liner 4. Even when the premixed pre-evaporation of the main fuel is promoted to obtain low-nitrogen oxides and the fuel is diluted, the fuel concentration is relatively high at the intersection of the internal and external flows. The combustion gas is surely ignited, and the main combustion flame Fm is easily formed.

At the intersection of the two fluids, the direction of the inner and outer flows changes at intervals in the circumferential direction.
As indicated by the arrow, a vortex V is formed at each location and the fluid stays at this location. Therefore, in the interior of the pilot chamber 23, a part of the pilot flame Fp stays in the vortex V portion and is retained. A flame is generated and the occurrence of the blowout phenomenon is prevented.

[0018]

The gas turbine combustion device according to the present invention has the following excellent effects. (1) Since the pilot chamber is provided with a lobe mixer that divides the internal and external flows into a plurality of circumferentially divided portions and mixes them, the pilot combustion gas and the unburned gas of the main fuel are guided inward and outward in a state where the pilot combustion gas and the main fuel are divided into a plurality of portions in the circumferential direction. Then, the unburned gas is ignited reliably by the formation of the main combustion flame, the amount of nitrogen oxides produced during combustion is reduced, and efficient combustion is possible. (2) In the lobe mixer portion, the pilot combustion gas and the unburned gas are guided inward and outward, so that a vortex is formed at the intersection of both fluids and the fluid is accumulated, whereby the pilot flame is retained. Since the flame is held by being guided to a location, it is possible to improve the flame holding performance during the entire combustion even when the fuel is lean, and to continue the combustion in a stable state.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a gas turbine combustion apparatus according to the present invention.

FIG. 2 is a front sectional view showing an embodiment of a gas turbine combustion device according to the present invention.

3 is a right side view of a lobe mixer portion in FIG. 2. FIG.

[Explanation of symbols]

 1 casing 2 pilot combustor 3 premixer 4 combustor liner 21 pilot fuel pipe 22 pilot fuel injection valve 23 pilot chamber 24 intake port 25 spark plug 26 pilot stage 31 premix preevaporation pipe 32 isolation sleeve 33 main stage 34 main Fuel injection means (fuel spray ring) 35 Main fuel supply pipe 40 Lobe mixer Fp Pilot flame Fm Main combustion flame V Vortex

Claims (1)

[Claims] 1. A pilot combustor (2) for combusting fuel injected from a pilot fuel injection valve (22) inside a pilot chamber (23), and is arranged concentrically around the pilot combustor. A premixer (3) comprising a premixer (3) forming an annular main stage (33) around the pilot chamber and extending downstream to a premix preevaporator pipe (31). , A main fuel injection means (34) arranged upstream of the main stage for injecting fuel into the air flow, and at the downstream end of the pilot chamber, the pilot combustion gas is divided into a plurality of circumferentially divided parts and guided to the outside. In addition, the lobe mixer (40) that divides the mixed flow of the main stage in the circumferential direction and guides the mixed flow inward to mix them.
A combustor for a gas turbine, comprising: