JPH08610Y2 - Gas turbine combustor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention is a two-stage combustion type having a pilot combustion region for diffusively burning a primary fuel and a premixed combustion region for burning a premixed fuel and air. In the improvement of the gas turbine combustor, the catalyst combustor is provided between the pilot combustion region and the premixed combustion region, and the secondary fuel for catalytic combustion is supplied to the latter stage of the pilot combustion region. It relates to a gas turbine combustor.

[Conventional technology]

As a conventional combustor for supplying combustion gas to a gas turbine to drive the gas turbine, as shown in FIG. 5, a pilot combustion region 3 provided with a swirler 2 and a primary fuel F ₁ from a pilot burner ₁ are primary. Flame is maintained by combustion,
Next, by burning the mixture of the secondary fuel F ₂ and air in advance in the premixed combustion region 4 having a diameter D ₂ larger than the diameter D ₁ of the pilot combustion region 3, that is, the main combustion region, the combustion is performed. A combustor designed to reduce the NO _x content in the gas G is used as a diffusion / premix type two-stage combustor.

In the case of this combustor, about 600 in pilot combustion zone 3
From 700 to 1300 in premixed combustion zone 4
Combustion is carried out at a temperature of ℃, and a high temperature combustion gas G of about 1300 ℃ is supplied to the gas turbine inlet at the latter stage (not shown).

Next, as shown in FIG. 4, preheating to burn at about 400 to 500 ° C. while supplying the primary fuel F ₁ and the fuel air A as shown in FIG. 4 to further reduce NO _x than the above. A premixed combustion region 5 and a catalytic combustion region 7 composed of a catalytic combustor 6 are provided, and secondary fuel F ₂ and combustion air A are supplied to the catalytic combustion region 7 to perform combustion at 500 to 1300 ° C. Performing catalytic combustors have also been used.

In the case of this combustor, by using the catalytic combustor 6,
Although it has the effect of reducing NO _x , the catalyst is exposed to a high temperature of 1300 ° C for a long time, and a catalyst that can withstand such high temperature combustion for a long time has not been obtained at present. In addition, this high temperature catalytic combustor 6 is inevitably relatively large, and such a large catalytic combustor 6 is not effective for supporting the catalyst, and therefore the catalyst is easily destroyed. There was a problem in the durability of the catalyst.

In other words, in the conventional catalytic combustor, NO _x can be reduced by effectively combusting, but there is a problem that the catalyst has to react at a high temperature, and therefore the catalyst deteriorates quickly. In addition, there was a problem in mechanical strength.

On the other hand, a catalytic combustion type gas turbine combustor having a catalytic combustion unit is proposed in Japanese Patent Laid-Open No. 59-107119.
However, in this gas turbine combustor, a large number of mixed gas supply pipes are pierced in the catalytic combustion part and ejected to the rear of the catalyst for combustion, so the absolute amount of the catalyst decreases as much as the pipes are provided, As a result, there is a problem that endurance is reduced.

[Purpose of device]

The purpose of the present invention is to maintain the endurance of the catalytic combustor as designed, reduce NO _x over a wide range from partial load to rated operation, and reduce the size of the catalytic combustor to further improve its durability. It is to provide a gas turbine combustor capable of improving the fuel consumption.

[Constitution of device]

That is, the gas turbine combustor of the present invention uses the primary fuel
It has a pilot combustion region 3 in which F ₁ is diffused and burned, and a premixed combustion region 4 in which the premixed tertiary fuel F ₃ and air are burned, and a secondary fuel F ₂ is provided behind the pilot combustion region 3. Of the catalyst combustor 7 at the rear of the portion for supplying the secondary fuel F ₂ and at the front of the premixed combustion region 4.
Is provided.

The gas turbine combustor according to the present invention has the flame holding property of the primary fuel F ₁ by diffusion combustion, and at the same time the secondary fuel F ₂ is burned with low NO _{x in} the latter stage of the pilot combustion region 3 by lean premixed combustion. I am trying to let you.

Then, by providing the catalytic combustor 7 on the downstream side of the diffusion premix combustor that supplies the secondary fuel F ₂ in the latter stage of the pilot combustion region 3, the secondary fuel F ₂ is reduced during the partial load operation of the gas turbine. When the combustion efficiency of the premixed combustion is reduced, the unburned portion is burned in the downstream catalytic combustor 7 to maintain the outlet temperature of the catalytic combustor 7 as high as possible to improve the combustion efficiency of the tertiary fuel F ₃ . Is configured to be able to.

Since the combustor according to the present invention can mainly perform lean premixed combustion, the gas temperature at the inlet of the catalytic combustor 7 is as high as about 850 to 1000 ° C in normal operation.
However, at such a temperature, even if the catalyst deteriorates, the activity of the catalyst is high, so that it is possible to continue the combustion with high combustion efficiency for a long time.

Further, the reducing function of the catalyst reduces the NO _x generated in the premixed combustion on the upstream side to N ₂ gas, which can further reduce the NO _x .

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of a gas turbine combustor according to an embodiment of the present invention.

First, in the gas turbine combustor shown in FIG. 1, in the inner cylinder 11 provided inside the heat-resistant outer cylinder 10, the pilot burner is provided in the pilot combustion region 3 provided with the swirler 2 as in the conventional example shown in FIG. The primary fuel F ₁ from No. ₁ is flame-held and primary burned. Then, in the premixed combustion region 4 having a diameter D ₂ larger than the diameter D ₁ of the pilot combustion region 3, main combustion is performed with the premixed tertiary fuel F ₃ and air.

Therefore, in the present invention, in particular, the secondary fuel F ₂ is burned at the end portion of the diameter D ₁ on the pilot combustion region 3 side of the two-stage combustor consisting of the pilot combustion region 3 and the premixed combustion region 4 described above. The catalytic combustor 13 is installed.

In the gas turbine combustor having the above configuration,
Preheating and flame holding by diffusion combustion are performed in the pilot combustion region 3 where the primary fuel F ₁ is burned, and the burning temperature is 40
It is maintained at about 0-500 ℃.

Next, in the catalytic combustion region 7, the secondary fuel F ₂ is catalytically burned to uniformly burn at 500 to 1000 ° C., and the combustion gas generated by this catalytic combustion is mixed with the tertiary fuel F ₃ in the premixed combustion region 4. Is added and burned to generate a combustion gas G having a temperature of 1000 to 1300 ° C., which is introduced into the gas turbine.

FIG. 3 (A) shows a preferable temperature range of each part of the gas turbine combustor, and the temperature of the catalytic combustion region 7 is
It is about 850-1000 ℃.

FIG. 3B shows the relationship between the NO _x generation amount and the combustion efficiency of each part of the combustor drawn corresponding to FIG.

Since the present invention is configured as described above, the temperature of the catalytic combustion region 7 can be lowered to 850 to 1000 ° C., and the combustion in the premixed combustion region 4 provided on the downstream side of this region 7 can be performed. The temperature can be lowered to about 1000 to 1300 ° C.

As described above, in the present invention, by providing the catalytic combustor 13 at the end of the pilot combustion region 3, uniform combustion is performed at a relatively low temperature, and uniform combustion is performed at a low temperature. Since it does not generate high-temperature combustion gas of 1500 ° C or higher, it does not generate high-concentration NO _x .

That is, since the catalytic combustor 13 reacts uniformly at a low temperature of 1000 ° C. or less, the combustion gas generated from the catalytic combustor 13 at a uniform temperature is further uniformly premixed with the tertiary fuel F ₃ and air. Will be introduced. Therefore, even in this premixed combustion region 4, uniform combustion is performed. As a result, 1500
Since it becomes difficult to generate high-temperature combustion gas above ℃, the amount of NO _x generated also decreases.

On the other hand, the diameter D ₁ of the catalytic combustor 13 is equal to the diameter D ₂ of the premix combustion region 4.
Therefore, the catalytic combustor 13 can be downsized and the reaction temperature of the catalyst can be suppressed to about 1000 ° C.
Its durability is improved.

Next, Fig. 2 shows NOx against gas turbine load (%).
The generated amount is shown in a diagram. The case of the embodiment of the present invention in FIG. 1 is A, the case of the conventional diffusion premix two-stage combustion of FIG. 5 is B, and the conventional diffusion combustor. The case of is shown in each diagram of C, and by adopting the combustor of the present invention also from these diagrams, the generation amount of NO _x is remarkably improved as compared with the conventional one as the gas turbine load increases. I understand.

[Effect of device]

As described above, the gas turbine combustor of the present invention comprises the pilot combustion region 3 for diffusively burning the primary fuel F ₁ and the premixed combustion region 4 for burning the premixed tertiary fuel F ₃ and air. 2 at the rear of the pilot combustion area 3
The secondary fuel F ₂ is supplied, and a catalytic combustor 7 is provided behind the portion for supplying the secondary fuel F ₂ and in front of the premixed combustion region 4.

Therefore, the durability of the catalytic combustor 7 can be maintained as designed, and low NO _x combustion can be performed over a wide range from partial load to rated operation.

Further, since the catalytic combustor can be made smaller than the conventional one, there is an advantage that it is excellent in manufacturability and durability and can be manufactured at a low price.

Furthermore, the temperature rise in the part of the catalytic combustor 7 is about 500 to 100.
Since the temperature can be controlled within the range of 0 ° C., it does not reach 1300 ° C. unlike the conventional catalyst combustor, and the durability of the catalyst is further improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a gas turbine combustor according to an embodiment of the present invention, and FIG. 2 is a NO _x generation amount with respect to a gas turbine load of the combustor according to the embodiment of FIG. FIG. 3 (A) is a diagram showing a preferable combustion temperature in the gas turbine combustor of FIG. 1, and FIG. 3 (B) is NO _x drawn corresponding to FIG.
It is a figure which shows the production amount and combustion efficiency. 4 and 5 are vertical sectional views of different conventional combustors. 3 ... Pilot combustion region, 4 ... Premixed combustion region, 7
...... Catalytic combustion area, 13 ...... Catalytic combustor, F ₁ …… Primary fuel, F ₂ …… Secondary fuel, F ₃ …… Tertiary fuel.

Claims (1)

[Scope of utility model registration request] 1. A pilot combustion region (3) for diffusively burning a primary fuel (F ₁ ) and a premixed combustion region (4) for burning a premixed tertiary fuel (F ₃ ) and air. And having a secondary fuel (F ₂ ) supplied to the rear part of the pilot combustion region (3) and behind the part supplying the secondary fuel (F ₂ ), the premixed combustion region (4) A gas turbine combustor in which a catalytic combustor (7) is provided in the front part of the gas turbine combustor.