JPH11230549A - Gas turbine combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the fluctuation of a desired fuel flow ratio by controlling the flow of fuel to be supplied to a pilot burner, and controlling the flow of fuel to be supplied to a premixing burner and a fuel nozzle. SOLUTION: Air compressed with a compressor is divided to flow to a diffusing burner 80 and a premixing burner 90, and a fuel nozzle 11, which sprays fuel to the air flowing to the premixing burner 90, and a fuel nozzle 30, which sprays fuel to be premixed with the air flowing from a common header 10 to a diffusing burner 80, are arranged. Then, based on the ratio of the area of the nozzle hole of the fuel nozzle to jet fuel to the premixer 4 to the area of the nozzle hole of the fuel nozzle 30 to supply fuel to the diffusing burner 80, the flow of fuel is controlled, and also the ratio of the flow of the fuel to be supplied to a pilot burner is controlled within a fixed range. Hereby, the fluctuation of the desired fuel flow ratio can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas turbine combustor, and more particularly to a gas turbine combustor provided with a pilot burner and a premix burner.

[0002]

2. Description of the Related Art In recent years, in order to reduce the amount of nitrogen oxides (hereinafter referred to as NOx) emitted from a gas turbine combustor, there is a strong demand for a combustion method capable of suppressing the generation of NOx.

As a combustion method with a small amount of exhausted NOx, there is premixed combustion in which fuel and air are mixed in advance before a combustion reaction and then burned. In general, the NOx generation amount increases exponentially as the combustion flame temperature increases. By performing premixed combustion, it is possible to prevent the combustion flame temperature from locally increasing, so that by increasing the ratio of air to fuel and making the premixed air lean, the combustion flame temperature is reduced,
NOx emissions can be reduced. Therefore, in order to respond to the demand for lowering NOx, which has become increasingly strong in recent years, the ratio of operation in lean premixed combustion is increasing.

However, in general, lean premixed combustion has characteristics that a flame is easily blown out and combustion oscillation is easily generated as compared with diffusion combustion in which air and fuel are mixed and burned.
Operating range for stable combustion is narrow. Therefore, it is necessary to skillfully combine diffusion combustion and lean premixed combustion in order to reduce NOx while ensuring stable combustion.

Japanese Patent Publication No. Hei 6-502240 discloses a pilot burner for supplying diffusion fuel, a premix burner for supplying premixed fuel, and a fuel for supplying premixed fuel to be premixed in an air supply path of the pilot burner. It is described that each nozzle is provided. It is described that when the load is 40% or less, diffusion combustion is performed by a pilot, and when the load is 40% or more, premix combustion is performed by a pilot burner using the fuel nozzle and premix combustion is performed using a premix burner.

[0006]

However, when premix combustion is performed not only by the premix burner but also by the pilot burner, the ratio of the fuel flow rates supplied to the premix burner and the pilot burner is required to maintain stable combustion. It is important that is within a certain range. Generally, in order to reduce the emission NOx, it is desirable that the fuel concentration (fuel-air ratio) of each part of the combustor be uniform. Therefore, if the air flow supplied to the premix burner is several times (for example, 8 times) the air flow of the pilot burner as in a normal low NOx combustor, the fuel flow of the pilot burner during premix combustion is premixed. Desirably a fraction of the burner (eg, about 1/8).

However, in an actual combustor, the flow rate of fuel supplied to the pilot burner depends on the amount of NOx discharged during premixed combustion.
It is common to operate at a value lower than the fuel flow rate required from the viewpoint of reduction. This is because if combustion oscillation occurs in a state where the fuel-air ratio distribution in the combustor is uniform, an extremely large pressure amplitude may result. Therefore, the fuel flow ratio between the premix burner and the pilot burner during premix combustion is carefully set. However, when each fuel system has its own fuel system and controls the fuel flow, as is usually done, in a gas turbine composed of a plurality of combustor cans, there is a deviation in the fuel flow in each combustor can. This may cause a combustor can in which the fuel flow ratio is not as set. Further, when the fuel flow rate fluctuates due to the load change, there is a possibility that a time range in which the fuel flow rate does not become as set may appear due to the difference in the response characteristic of the fuel flow rate change of the fuel valve used for each fuel system.

Accordingly, an object of the present invention is to provide a gas turbine combustor which can easily suppress a change in a desired fuel flow rate ratio even when a fuel flow rate changes and can achieve stable combustion while reducing NOx emission. It is in.

Another object of the present invention is to provide a highly efficient or compact gas turbine capable of easily suppressing a change in a desired fuel flow rate ratio even when a fuel flow rate changes, and achieving stable combustion while reducing exhaust NOx. Is to do.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a combustion chamber for supplying and burning fuel and air, a pilot burner for supplying fuel and air to the combustion chamber, and an air supply for the pilot burner. A fuel nozzle for spraying fuel to be premixed, a premix burner for supplying a premixed gas of fuel and air to the combustion chamber, and a first fuel control means for controlling a flow rate of the fuel supplied to the pilot burner And second fuel control means for controlling both the fuel flow supplied to the premix burner and the fuel flow supplied to the fuel nozzle.

Specifically, for example, a diffusion burner is arranged at the center of the combustor, and one premix burner is provided around the diffusion burner.
In one or more gas turbine combustors, a fuel header for supplying fuel to a fuel nozzle of the premix burner has at least a portion of the fuel header facing a flow path of air flowing into the diffusion burner. And a fuel nozzle is disposed at a portion of the fuel header facing a flow path of air flowing into the diffusion burner, and fuel can be supplied from the fuel header to both the premix burner and the diffusion burner. I did it.

Alternatively, a combustion chamber for supplying and burning fuel and air, pilot air supply means for supplying air to the combustion chamber, and a pilot burner having a diffusion fuel nozzle for spraying fuel, and the air supply means Nozzle for spraying fuel to be premixed with air flowing through the fuel cell, premixed air supply means for supplying air to the combustion chamber, and premixed fuel nozzle for spraying fuel to be premixed with the air A burner, a fuel header for supplying fuel to the fuel nozzle and the premixed fuel nozzle, and a fuel flow control unit provided in a fuel supply path for supplying fuel to the header,
It is characterized by having.

[0013] More specifically, the fuel is supplied to the diffusion fuel nozzle in a range lower than the first partial load of the gas turbine, and the range exceeds the second partial load lower than the first load. And a control device that controls the fuel flow control means to supply fuel.

In this way, even when the fuel flow rate changes, the fluctuation of the desired fuel flow rate ratio can be easily suppressed, and the discharge N
Achieve stable combustion while reducing Ox.

[0015] The flow rate of fuel injected from the fuel nozzle increases or decreases in proportion to the amount of fuel supplied to the premix burner connected to the same fuel header. Also, for the fuel nozzle and the fuel nozzle of the premix burner, if the production of the fuel injection hole and the evaluation of the fuel ejection characteristics are appropriately performed, the fuel flow rate supplied to the premix burner and the air flow path to the diffusion burner The distribution can be accurately grasped. From this, when the maximum fuel flow rate is supplied to the premix burner in the operation range of the gas turbine combustor, the fuel supplied from the same fuel header to the air flow path of the diffusion burner can also be at the maximum flow rate. At this time, it is desirable that the fuel concentration obtained from the flow rate of the air flowing through the air flow path is equal to or lower than the concentration condition capable of holding the flame. For example,
When using natural gas as the fuel, determine the diameter and number of the fuel nozzles so that the weight ratio of the fuel ejected from the fuel nozzle arranged in the fuel header and the air flowing into the diffusion burner is 0.02 or less. It is desirable.

Alternatively, a combustion chamber for supplying and burning fuel and air, pilot air supply means for supplying air to the combustion chamber, and a pilot burner having a diffusion fuel nozzle for spraying fuel, and the air supply means Nozzle for spraying fuel to be premixed with air flowing through the fuel cell, premixed air supply means for supplying air to the combustion chamber, and premixed fuel nozzle for spraying fuel to be premixed with the air A burner, and a fuel header for supplying fuel to the fuel nozzle and the premixed fuel nozzle, wherein a length of a region where the fuel nozzle protrudes into the air passage is set such that the premixed fuel nozzle protrudes into the air passage. It is characterized in that it is configured to be shorter than the length of the region. Thereby, the pressure loss of the supply air by the nozzle installed in the flow path can be suppressed, and highly efficient gas turbine operation can be performed.

Alternatively, a combustion chamber for supplying and burning fuel and air, a diffusion fuel nozzle for spraying the fuel, and a flow formed between the nozzle and a cylindrical member located around the nozzle. A pilot burner provided with pilot air supply means for supplying air to the combustion chamber via a passage, a fuel nozzle for spraying fuel to be premixed with air flowing through the air supply means, and a pilot nozzle for supplying air to the combustion chamber. A premix burner having a mixed air supply means and a premix fuel nozzle for spraying fuel to be premixed into the air, and a fuel header for supplying fuel to the fuel nozzle and the premix fuel nozzle; The fuel outlet of the fuel nozzle is located on the axial center side of the combustion chamber from the fuel outlet of the premix nozzle, and is configured to be located on the upstream side of the air flow from the flow path.
It is characterized by the following.

As a result, the gas turbine combustor can be further suppressed in size and can be made compact. More preferably, the above-described nozzle length is employed.

Alternatively, there is provided a compressor for compressing and discharging air, a combustor for supplying and burning the air and fuel discharged from the compressor, and a turbine for supplying and driving the combustion gas. In the gas turbine, the combustor includes a combustion chamber for supplying and burning fuel and air, a pilot burner provided with pilot air supply means for supplying air to the combustion chamber, and a diffusion fuel nozzle for spraying fuel. A fuel nozzle for spraying fuel to be premixed with air flowing through the air supply means, a premixed air supply means for supplying air to the combustion chamber, and a premixed fuel nozzle for spraying fuel to be premixed in the air; A premixed burner, and a fuel header for supplying fuel to the fuel nozzle and the premixed fuel nozzle, wherein the fuel nozzle of the fuel nozzle has
The fuel supply port of the premixing nozzle is disposed on the outer peripheral side of the combustion chamber, and is disposed downstream of the air flow from a branch portion that branches the air supplied from the compressor into the pilot burner and the premix burner. , Characterized in that.

[0020] Thereby, the gas turbine combustor can be further suppressed in size and can be made compact. More preferably, the above-described nozzle length is employed.

Alternatively, a combustion chamber for supplying and burning fuel and air, a pilot burner for supplying fuel and air for diffusion combustion in the combustion chamber, and a fuel for premixing with air supplied to the pilot burner may be used. A fuel nozzle to be sprayed, a premix burner for supplying a premixed air of fuel and air to the combustion chamber, a diffusion fuel control means for controlling a flow rate of the fuel supplied to the pilot burner, and a supply to the premix burner. A plurality of premixed fuel control means for controlling the fuel flow rate, and one premixed fuel supply means of the plurality of premixed fuel control means comprises a fuel flow rate supplied to the premixed burner and a fuel flow rate supplied to the fuel nozzle. It is configured to be controlled together with the fuel flow rate.

Specifically, for example, by dividing the fuel header into a plurality of parts and connecting different fuel systems to the divided fuel headers, the fuel flow supplied to the divided fuel headers can be adjusted respectively. In addition, a fuel nozzle is provided in a portion of the divided fuel header that faces a flow path of air flowing into the diffusion burner only in a specific fuel header.

Further, a combustion chamber for supplying and burning fuel and air, a pilot burner for supplying fuel and air for diffusion combustion in the combustion chamber, and a fuel for premixing with air supplied to the pilot burner are provided. A method for operating a gas turbine combustor, comprising: a fuel nozzle to be sprayed; and a premix burner that supplies a premixed gas of fuel and air to the combustion chamber, wherein the first gas turbine load region includes A first stroke of diffusion combustion by a pilot burner, and a second load region higher than the first gas turbine load region; diffusion combustion by the pilot burner; premix combustion by the premix burner; The fuel is supplied to the pilot burner to perform premix combustion, and the load is changed by changing both the amount of fuel supplied to the premix burner and the fuel amount supplied to the fuel nozzle. And in a third load range higher than the second gas turbine load range, the diffusion combustion is stopped, premixed combustion is performed by the premixed burner, and fuel is supplied to the combustion nozzles by a pilot burner. And a third step of performing premix combustion.

With the above configuration, the premixed gas is supplied from the fuel header to the diffusion burner together with the premixed burner. Therefore, the fuel for diffusion combustion in the diffusion burner can be reduced, and the emission NOx is reduced. However, when the fuel for diffusion combustion is generally supplied to the diffusion burner, the premixed gas flows into the diffusion flame, and the effect of reducing the emission NOx is reduced.

Therefore, it is desirable to shut off the supply of fuel for diffusion combustion to the diffusion burner as much as possible. In this case, as described above, the fuel flow supplied from the fuel header of the premixed burner to the diffusion burner has an upper limit, but the entire premixed combustion becomes possible, and the premixed burner is provided by the amount of the fuel supplied to the diffusion burner. Can reduce the concentration of fuel to be burned.
On the other hand, as described above, the premixture injected from the diffusion burner is
Although it is a concentration that cannot maintain a flame by itself, it is burned by a diffusion combustion flame or a combustion flame of a premixed burner. Therefore, the total emission NOx is reduced.

[0026]

(Embodiment 1) An embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. FIG. Figure 1
2 is a cross-sectional view of the gas turbine combustor according to the present embodiment, FIG. 2 is a cross-sectional view showing the fuel header according to the present embodiment extracted from FIG. 1, and FIG. 3 is a cross-sectional view taken along the line AA of FIG. Show. In the combustor, a diffusion burner 80 with a swirler having a swirler blade 2 is arranged on a central axis, and a premix burner 90 having a ring-shaped flame stabilizer 3 and a premixer 4 is arranged on the outer periphery thereof. .

In FIG. 1 and the like, the combustor is installed in a gas turbine. Air 40 compressed by a compressor (not shown) is supplied. Further, a large number of combustors shown in FIG. 1 and the like are provided in the circumferential direction. Here, the supplied air and fuel are burned to generate combustion gas. Combustion gas generated from many combustors is supplied to a turbine (not shown) to drive the turbine. A generator is connected to the turbine, and the generator rotates to generate power when the turbine is driven. This embodiment will be described below by taking a gas turbine combustor constituting a gas turbine power plant with a low NOx emission as an example.

The fuel 50 is supplied to the diffusion burner 80 from the fuel supply device 210 by the fuel nozzle 1. The fuel 50 flows around the fuel nozzle, is jetted into a swirl flow 70 formed by the jet flow 60 passing through the swirl vanes 2, and diffusely burns.

On the other hand, the fuel nozzle 11
And a portion of the air 40 is supplied to the combustion chamber 200 and burned as a premixed air 41 by mixing with the air. The present embodiment shows an example in which the flame is ejected from the inner and outer circumferences of the ring-shaped flame stabilizer 3 and burns. As a result, the premixed gas is recirculated to the circulating flow 75 formed downstream of the ring-shaped flame stabilizer 3.
Premixed combustion stably due to the effect of

The premixer 4 has a plurality of fuel nozzles 11
Is disposed, and the fuel nozzle 11 supplies fuel to the fuel nozzle 1.
It is connected to the fuel header 10 which is set to 1. The fuel header 10 distributes the fuel flowing through the fuel adjusting means described later to each fuel nozzle. A part of the fuel header 10 faces the air flow path 20 of the air flowing to the diffusion burner 80, and a plurality of fuel nozzles 30 are arranged so as to jet fuel into the air flow path 20.

Thus, the air compressed by the compressor is:
It is branched so as to flow to the diffusion burner 80 and the premix burner 90. A fuel nozzle for spraying fuel to air flowing to the premix burner and a fuel nozzle 30 for spraying fuel to be premixed to air flowing from the common header to the diffusion burner are arranged.

The length of the area where the fuel nozzle 30 contacts the supply air is shorter than the length of the area where the fuel nozzle 11 of the premix burner contacts the supply air.

Further, the length from the header 10 to the fuel outlet 301 of the fuel nozzle 30 is formed to be shorter than the length from the header 10 to the fuel outlet 302 of the fuel nozzle 11. Fuel nozzle 3 of fuel nozzle 11
The fuel injection port 301 of the fuel nozzle 30 is located on the upstream side in the longitudinal direction of the combustor from the fuel nozzle 02.

The fuel injection port of the fuel nozzle 30 is arranged on the outer peripheral side of the combustion chamber from the fuel injection port of the fuel nozzle 11 of the premix burner. The air supplied from the compressor is disposed downstream of the air flow from a branching portion where the air supplied to the compressor is branched into the pilot burner and the premix burner.

The fuel header 10 is divided into four parts as shown in FIG. 3, and each of the divided parts 12, 13, 14, 15 is provided with eight fuel nozzles 11 for injecting fuel into the premixer 4.
In this embodiment, four fuel nozzles 30 for ejecting fuel into the air flow path 20 to the diffusion burner 80 are arranged. Also, each divided part 1
Reference numerals 2, 13, 14, and 15 are respectively connected to a fuel system (not shown), and are individually connected to fuel flow rate adjusting means (211, 21).
Adjustment is made possible by 2). However, the number of divisions, the number of fuel nozzles, and the number of fuel systems are not particularly limited. Unlike FIG. 3, the fuel header is not divided, and the flow rate may be adjusted by one fuel flow rate adjusting means. Note that a stop valve 213 is provided on the upstream mother system of each system having 211.

The premix burner is connected to a plurality of fuel systems, and a gas turbine combustor is configured to switch the premix burner to be operated according to the load. The fuel header is divided and arranged corresponding to each fuel system. In this case, the diameter and the number of injection holes of the same combination of fuel nozzles can be set for each fuel header. Each fuel header may have a different injection hole diameter or a different number of fuel nozzles. In the latter case, the flow rate of fuel flowing into the diffusion burner can be adjusted by adjusting the fuel flow rate supplied to each premixed fuel system.

It is desirable that the outlet of the diffusion burner has a flow rate higher than that at which the flame does not flash back.

The gas turbine combustor according to the present embodiment is operated by the diffusion burner 80 alone when the gas turbine load is small. When the load reaches a predetermined value in response to the increase in load, each of the divided portions 12, 13, 14,.
Then, the fuel is supplied to the premix burner 15 and the premix burner 90 is operated. However, the fuel supply order of the divided portions 12, 13, 14, 15 is not particularly limited. When the load becomes another predetermined load higher than the predetermined load, the supply of the diffusion fuel to the diffusion burner 80 is stopped.

When the premix burner 90 is used, when fuel is supplied to the fuel header 10, the premix fuel is supplied to the air from the fuel nozzle 11 to the premix burner 90, and the diffusion burner 80 is supplied from the fuel nozzle 30. Air flow path 2 to
The fuel 51 is jetted to zero for premixing. The fuel 51 passes through the air flow path 21 shown in FIGS.
The gas is sufficiently mixed with the air 42 until the pressure reaches 0, and is jetted as a jet flow 60 of a premixed gas. Therefore, in this embodiment, the premixed gas can be supplied to the diffusion burner 80 without adding a fuel system. Here, the distance of the air flow path from the fuel injection hole of the fuel nozzle 30 to the injection port from the diffusion burner 80 is set to 20.
When the thickness is 0 mm or more, the mixing state of fuel and air can be improved.

Here, when natural gas is used as fuel, the jet flow 60 of the premixed gas is set to a fuel concentration such that the weight ratio of fuel to air is not more than 0.02.
This cannot hold the flame by itself. However, the diffusion burner 8
Since the combustion flame of the premixed burner 90 is present around the zero, the jet 60 can be ignited and burned by these hot combustion gases. Also, the flow velocity when the jet flow 60 passes through the swirling blade 2 is set to be 40 m / s or more to prevent flashback.

Generally, the emission NOx when burned at the same fuel concentration is several times larger in diffusion combustion than in premix combustion. In this embodiment, since the jet flow 60 of the premixed gas is also supplied to the diffusion burner 80, the amount of diffusion fuel can be reduced by that amount, and the emission NOx decreases. However, when there is a diffusion flame in which a local high-temperature portion is formed, the effect of reducing the emission NOx is limited. Then, when the fuel supply from the fuel nozzle 1 is stopped (control means 212 is closed),
The entire combustor can be premixed combustion, and the emission NOx can be reduced more reliably.

The load is further increased to a higher load than the load that disclosed the premix combustion (one of the control means 211 is opened) and exceeds a predetermined load (for example, a predetermined load set from a range of 40% to 60% load). Then, the supply of fuel to the fuel nozzle 1 is stopped (the control means 212 is closed), and the operation shifts to the operation of only the premix combustion. The load is controlled by controlling the amount of fuel for premix combustion.

When the fuel nozzle 30 is disposed in the fuel header 10 and the lean premixed gas is supplied to the diffusion burner 80 as in this embodiment, the jet 60 of the diffusion burner 80 is a lean premixed gas. The fuel concentration of the premixed gas 41 can be reduced by the middle fuel flow rate, and the emission NOx decreases. The jet 60 of the lean premixed gas is ignited by the combustion flame of the premixed burner 90 and burns. Further, since the fuel concentration is low, the emission NOx from the portion is extremely small.

When the fuel supply from the fuel nozzle 1 is stopped (the control means 212 is closed) and the entire combustor is set to the premixed combustion, the exhausted NOx generally has a fuel concentration (fuel / air ratio) in the premixed gas. (In one example, the fourth power). Therefore, if fuel is not supplied to the diffusion burner 80,
Since the air flow rate flowing through the diffusion burner does not substantially act as combustion air, the fuel concentration in the premixed gas increases by that amount, and the exhaust NOx increases. On the other hand, when the fuel nozzle 30 is disposed on the fuel header 10 and the lean premixed gas is supplied to the diffusion burner 80 as in the present embodiment, the air flowing through the diffusion burner can act as combustion air, and Therefore, the emission NOx can be reduced. Note that the jet 60 of the diffusion burner 80 is a lean premixed gas, and is ignited by the combustion flame of the premixed burner 90 and burns. Further, since the fuel concentration is low, the emission NOx from the portion is extremely small.

According to this embodiment, the premix burner 90
And the fuel ratio of the diffusion burner 80 can be kept constant even at the time of load fluctuation when the total fuel flow supplied to the combustor changes.
In the combustor according to the present embodiment, the premix burner 90 is set so that the flow velocity of the gas discharged into the combustion chamber is increased, thereby preventing flashback in which the flame moves from the low flow velocity portion to the upstream side. On the other hand, the diffusion burner 80 basically prevents the flashback by lowering the fuel concentration, while securing the air flow rate of a certain level or more. Accordingly, the diffusion burner 80 is smaller than the premix burner 90 in both the air flow rate and the fuel concentration. On the other hand, in order to reduce the emission NOx, it is better to reduce the fuel-air ratio of the entire combustor.
Is set so as to approach the fuel-air ratio. In addition, the fuel flow rate is set so that flashback or combustion vibration does not occur. In the present embodiment, the fuel flow rate ratio at the time of total premixed combustion is determined by the area of the injection hole of the fuel nozzle 11 that ejects fuel to the premixer 4 and the fuel nozzle 3 that supplies fuel to the diffusion burner 80.
It can be easily set based on the ratio to the injection hole area of 0. Further, according to the present embodiment, the fuel flow ratio between the premix burner 90 and the diffusion burner 80 thus set maintains a constant value even when the fuel flow fluctuates when the load changes. Therefore, both reduction of exhaust NOx and prevention of unstable combustion can be easily achieved.

According to this embodiment, the discharge N
The fuel flow ratio between the premix burner and the diffusion burner that can achieve both Ox reduction and stable combustion can be easily set, and the emission N
Stable combustion can be achieved while reducing Ox. Further, there is an effect that the fuel flow rate ratio can be maintained even when the fuel flow rate changes. Further, according to the present embodiment, it is possible to supply the premixed air to the diffusion burner without adding a fuel system, and there is also an effect that the emission NOx can be reduced.

The length of the area where the fuel nozzle 30 contacts the supply air is shorter than the length of the area where the fuel nozzle 11 of the premix burner contacts the supply air.
During the operation, pressure loss due to supply air can be suppressed, and efficient operation can be performed.

Also, the length from the header 10 to the fuel ejection port 301 of the fuel nozzle 30 is shorter than the length from the header 10 to the fuel ejection port 302 of the fuel nozzle 11. .

The fuel injection port 301 of the fuel nozzle 30 is located on the upstream side in the longitudinal direction of the combustor from the fuel injection port 302 of the fuel nozzle 11. Further, the fuel outlet of the fuel nozzle 30 is disposed closer to the outer periphery of the combustion chamber than the fuel outlet of the fuel nozzle 11 of the premix burner.

For this reason, the distance over which the premixing air supplied from the fuel nozzle 30 diffuses can be sufficiently ensured while suppressing an increase in the size of the combustor, so that good premixing combustion with a pilot burner is possible. Becomes

Further, it is preferable to provide a fuel injection port 301 of the fuel nozzle 30 at a portion where the air flow path is bent. The diffusion of the fuel can be promoted by the turbulence of the air. Therefore, the size can be further reduced.

Further, as is usual, when each has a separate fuel system and controls each fuel flow rate,
In a gas turbine composed of a plurality of combustor cans,
It is possible to suppress the possibility that a combustor can may appear in which the fuel flow rate varies in each combustor can and the fuel flow rate ratio does not become as set. Further, when the fuel flow rate fluctuates due to a load change, it is possible to suppress the fuel flow rate ratio from deviating from the setting. Furthermore, even in the event that a problem occurs in the fuel valve and the flow rate of fuel supplied to the pilot burner becomes excessive, it is possible to suppress an increase in the fuel-air ratio of the premixed air in the section.

Incidentally, when the fuel flow rate of the premix burner excessively increases, the exhaust gas temperature rises immediately due to the large fuel flow rate to the section, and the exhaust gas temperature normally applied to the gas turbine becomes high. The time required for the protection control to be activated to prevent the operation from becoming active is short. On the other hand, it takes time for the pilot burner to detect an abnormality for the smaller fuel flow rate ratio and to activate the protection, and during that time, the state where the fuel-air ratio of the portion is large may continue. According to the present embodiment, such a situation can be suppressed.

(Embodiment 2) Another embodiment according to the present invention will be described. The configuration of the present embodiment can basically use almost the same form as the first embodiment. As explained in FIG. 1,
A plurality of fuel nozzles 11 for supplying fuel to the premixer 4 are arranged on the fuel header 10. The fuel header 10 is divided into four parts 12, 13, 14, and 15. In this embodiment, as shown in FIG. 4, the structure of the fuel header 10 is different from that of the first embodiment shown in FIG. That is, in the present embodiment, a plurality of fuel nozzles 30 are arranged so that fuel is injected into the air flow path 20 to the diffusion burner 80 only in the divided portion 12 of the fuel header 10.

Similarly to the first embodiment, the gas turbine combustor according to the present embodiment is also operated by the diffusion burner 80 alone when the gas turbine load is small, and each divided portion of the fuel header 10 is operated in response to an increase in the load. , And the premix burner 90 is operated. In a situation where the load is low, the premix burner 90 is first supplied with fuel to the divided portion 13, and is supplied with fuel in the order of 14 and 15 as the load is increased. Control means 2
11 opening). At this time, fuel is supplied to the diffusion burner 80 from the divided portion to the premix burner 90. And then
The supply of the diffusion fuel to the diffusion burner 80 is stopped (the control unit 212 is closed).

As described in the first embodiment of FIG. 1, when the fuel is supplied to the divided portion 12 of the fuel header 10, the fuel 51 is supplied to the air passage 20 from the fuel nozzle 30 to the diffusion burner 80.
Squirts. Even if the fuel supplied to the header 10 is changed, the fuel can be distributed to the fuel nozzles 30 and the fuel nozzles 30 at a fixed ratio with high accuracy. The fuel 51 passes through the air flow path 21 shown in FIGS.
The gas is sufficiently mixed with the air 42 until the pressure reaches 0, and is jetted as a jet flow 60 of a premixed gas. Here, the jet flow 60 of the premixed gas is preferably set to a fuel concentration at which the flame cannot be maintained by itself. In this embodiment, the fuel header 1
Since the premixed combustion flame by the fuel supplied from the 0 divided portions 13, 14, 15 is formed in the premixed burner 90, the fuel of the jet flow 60 is burned by the combustion flame.
For this reason, it is possible to suppress an increase in unburned components.

According to the present embodiment, the lean premix is supplied to the diffusion burner after the load of the gas turbine is increased and the fuel flow supplied to the premix burner is increased. The air-fuel mixture is combusted by the combustion flame of the premix burner, and has the effect of suppressing the generation of unburned components.

Since the premixed air by the fuel supplied from the fuel header of the premixed burner to the diffusion burner is lean, the distribution of fuel and air and the structure of the entire combustor and the structure of the gas turbine must be carefully examined. In order to minimize the generation of unburned components in the entire operation load region, the fuel header for the premixed burner is divided into a plurality of fuel headers, and different fuel systems are connected to the divided fuel headers. A fuel flow rate supplied to the divided fuel headers can be adjusted, and a fuel nozzle is provided in a part of the divided fuel headers facing a flow path of air flowing into a diffusion burner only to a specific fuel header. It is effective to provide. Here, a plurality of premix burners may be arranged around the diffusion burner. The number may be equal to or greater than the number of fuel systems connected to the divided fuel headers. In the latter case, the same fuel header supplies fuel to multiple premix burners.

In such a combustor, the number of operating premix burners is increased in response to an increase in the gas turbine load. In this case, the flow rate of the fuel for diffusion combustion supplied to the diffusion burner may be reduced depending on the number of premixed burners operated even when the gas turbine load is small.
In such a state, when the premixed gas is supplied from the diffusion burner, the fuel flow rate for diffusion combustion is reduced by the fuel flow rate of the premixed gas. . On the other hand, the flow rate of fuel supplied to the premix burner increases as the load on the gas turbine increases. For this reason, when the gas turbine load is large, the premixed gas supplied from the diffusion burner is reliably burned by the combustion flame of the premixed burner, and the generation of unburned components does not matter.

Therefore, the gas header is not operated when the gas turbine load is small, and the position of the fuel header connected to the premix burner that supplies the fuel when the gas turbine load is largest is facing the air flow path flowing into the diffusion burner. When the fuel nozzles are arranged in the fuel cell, the load increases and the flow rate of the diffusion fuel supplied to the premix burner increases, and then the premix gas can be supplied to the diffusion burner. It is also possible to completely stop the diffusion fuel flow almost simultaneously with supplying fuel to the premix burner. This allows
Unburned components discharged from the diffusion burner can be reliably reduced.

(Embodiment 3) Another embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a sectional view of the gas turbine combustor according to the present embodiment, and FIG. 6 is a view of FIG. 5 viewed from the downstream side.

The present embodiment is basically the same as Embodiments 1 and 2 in that a diffusion burner 80 provided with the swirling blades 2 is arranged on the central axis. Are arranged. The premix burner 10
0 is a fuel nozzle 101, a swirl vane 102, a premixer 1
04. However, the configuration and number of the premix burners 100 are not particularly limited.

The fuel nozzle 101 is connected to the fuel header 10. The fuel header 10 partially faces the air flow path 20 to the diffusion burner 80, and this air flow path 20
A plurality of fuel nozzles 30 are arranged so as to eject fuel to the fuel cell.

The fuel outlet of the fuel nozzle 30 is located closer to the axis of the combustion chamber than the fuel outlet of the fuel nozzle 101 of the premix burner. From fuel header 10 to fuel nozzle 10
The length of the fuel nozzle 30
Is short to the fuel outlet 303.

The length of the fuel nozzle 30 facing the air flow path is shorter.

Further, it is configured to be located on the upstream side of the air flow from the flow path formed between the fuel nozzle 1 of the pilot burner and the cylindrical member 151 located around the nozzle 1. This is not the case when the cylindrical member 151 is not as shown in FIG.

In the case of the present embodiment, fuel is supplied to the premix burner 100 sequentially as the load increases. Along with this, fuel is supplied from the fuel nozzle 30 to the diffusion burner 80 and is ejected as the jet flow 60 of the lean premixed gas, so that the emission NOx is reduced by the same operation as described in the first and second embodiments. .

According to the present embodiment, there is an effect that emission NOx combustion can be reduced in a gas turbine combustor in which a plurality of tubular premix burners having swirling vanes around a diffusion burner are arranged.

[0069]

According to the present invention, there is provided a gas turbine combustor capable of easily suppressing a change in a desired fuel flow rate ratio even when the present fuel flow rate changes, and achieving stable combustion while reducing NOx emissions. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view of a gas turbine combustor according to one embodiment of the present invention.

FIG. 2 is a sectional view of a fuel header in the configuration of FIG.

FIG. 3 is a sectional view taken along the line AA of FIG. 2;

FIG. 4 is a sectional view taken along line AA of FIG. 2 according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view of a gas turbine combustor according to another embodiment of the present invention.

6 is a view of the burner configuration of FIG. 5 as viewed from a downstream side of the combustor.

[Explanation of symbols]

1, 11, 30, 101: fuel nozzle, 2, 102: swirl vane, 3: ring flame stabilizer, 4, 104: premixer,
10: fuel header, 12, 13, 14, 15: divided portion of fuel header, 20, 21: air flow path to premix burner, 40, 42: air, 41: premixed gas, 50, 51
... fuel, 60 ... jet flow, 70 ... swirl flow, 75 ... circulation flow,
80: diffusion burner, 90, 100: premix burner.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasutaka Komatsu 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Fumiharu Moriwaki 3-1-1 Sachimachi, Hitachi-shi, Ibaraki No. 1 Inside Hitachi, Ltd. Hitachi Plant

Claims (7)

[Claims] 1. A combustion chamber for supplying and burning fuel and air, a pilot burner for supplying fuel and air to the combustion chamber, and a fuel for spraying fuel to be premixed with air supplied to the pilot burner A nozzle; a premix burner for supplying a premixed mixture of fuel and air to the combustion chamber; first fuel control means for controlling a flow rate of the fuel supplied to the pilot burner; and a supply to the premix burner. And a second fuel control means for controlling both the fuel flow rate to be supplied to the fuel nozzle and the fuel flow rate to be supplied to the fuel nozzle. 2. A combustion chamber for supplying and burning fuel and air, a pilot burner provided with pilot air supply means for supplying air to the combustion chamber, and a diffusion fuel nozzle for spraying fuel, and the air supply means. Nozzle for spraying a fuel to be premixed with the air flowing through the combustion chamber, premixed air supply means for supplying air to the combustion chamber, and a premixed burner provided with a premixed fuel nozzle for spraying the fuel to be premixed with the air A gas header comprising: a fuel header for supplying fuel to the fuel nozzle and the premixed fuel nozzle; and a fuel flow control means provided in a fuel supply path for supplying fuel to the header. Turbine combustor. 3. A combustion chamber for supplying and burning fuel and air, a pilot burner provided with pilot air supply means for supplying air to the combustion chamber, and a diffusion fuel nozzle for spraying fuel, and the air supply means. Nozzle for spraying a fuel to be premixed with the air flowing through the combustion chamber, premixed air supply means for supplying air to the combustion chamber, and a premixed burner provided with a premixed fuel nozzle for spraying the fuel to be premixed with the air And a fuel header for supplying fuel to the fuel nozzle and the premixed fuel nozzle, wherein the length of the area where the fuel nozzle projects into the air passage is the area where the premixed fuel nozzle projects into the air passage. A gas turbine combustor configured to be shorter than a length of the gas turbine. 4. A combustion chamber for supplying and burning fuel and air, a diffusion fuel nozzle for spraying the fuel, and a flow formed between the nozzle and a cylindrical member located around the nozzle. A pilot burner provided with pilot air supply means for supplying air to the combustion chamber via a passage; a fuel nozzle for spraying fuel to be premixed with air flowing through the air supply means; and a fuel nozzle for supplying air to the combustion chamber. A premix burner provided with a premix fuel nozzle for spraying fuel for premixing the air with the mixed air supply means, and a fuel header for supplying fuel to the fuel nozzle and the premix fuel nozzle; A gas, wherein the fuel nozzle of the fuel nozzle is located closer to the axis of the combustion chamber than the fuel nozzle of the premixing nozzle, and is located upstream of the air flow from the flow path. Turbine combustor. 5. A compressor for compressing and discharging air, a combustor for supplying and burning the air and fuel discharged from the compressor, and a turbine for supplying and driving the combustion gas. In the gas turbine, the combustor is a combustion chamber that supplies and burns fuel and air, a pilot burner that includes a pilot air supply unit that supplies air to the combustion chamber, and a diffusion fuel nozzle that sprays fuel. A fuel nozzle for spraying fuel to be premixed with air flowing through the air supply means; a premixed air supply means for supplying air to the combustion chamber; and a premixed fuel nozzle for spraying fuel to be premixed with the air. A premix burner, and a fuel header for supplying fuel to the fuel nozzle and the premix fuel nozzle. The fuel nozzle of the fuel nozzle has a fuel jet of the premix nozzle. A gas turbine, which is disposed on the outer peripheral side of a combustion chamber and downstream of an air flow from a branch portion that branches air supplied from the compressor into the pilot burner and the premix burner. . 6. A combustion chamber for supplying and burning fuel and air, a pilot burner for supplying fuel and air for diffusion combustion in the combustion chamber, and a fuel for premixing air supplied to the pilot burner. A fuel nozzle for spraying; a premix burner for supplying a premixed gas of fuel and air to the combustion chamber; a diffusion fuel control means for controlling a flow rate of the fuel supplied to the pilot burner; and a supply to the premix burner. A plurality of premixed fuel control means for controlling the fuel flow rate, and one of the plurality of premixed fuel control means includes a fuel flow rate supplied to the premixed burner and a fuel flow rate supplied to the fuel nozzle. A gas turbine combustor characterized in that it is configured to control with a fuel flow rate to be controlled. 7. A combustion chamber for supplying and combusting fuel and air, a pilot burner for supplying fuel and air for diffusion combustion in the combustion chamber, and a fuel for premixing air supplied to the pilot burner. A method for operating a gas turbine combustor, comprising: a fuel nozzle to be sprayed; and a premix burner that supplies a premixed gas of fuel and air to the combustion chamber, wherein the first gas turbine load region includes: A first stroke of diffusing and burning by the pilot burner; and a diffusing combustion by the pilot burner in a second load region higher than the first gas turbine load region; and a premixing combustion by the premix burner; The fuel is supplied to the pilot burner to perform premix combustion, and the load is changed by changing both the amount of fuel supplied to the premix burner and the fuel amount supplied to the fuel nozzle. And stopping the diffusion combustion in a third load region higher than the second gas turbine load region, performing premix combustion with the premix burner, supplying fuel to the combustion nozzle, and performing pilot combustion with a pilot burner. And a third step of mixing and burning the gas turbine combustor.