JPH0618038A - Combustor for gas turbine and method of operating the same - Google Patents

Abstract

PURPOSE:To enable stable operation over a long period of time by suppressing generation of NOx and CO to an exceedingly low level in full load range including rated load and partial load in a gas turbine and maintaining stable condition of combustion in a full range of operation. CONSTITUTION:A combustor liner 25 is received in a combustor containing casing 23, and a main burner and a pilot burner 33, respectively, are provided on a head portion 25a of the combustor liner 25. The pilot burner 33 comprises a diffusion combustion burner 36 and a plurality of premix lean combustion burners 37 disposed on the outer peripheral portion of the diffusion combustion burner 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine combustor for premixing fuel with air for combustion, and particularly to a low NO
TECHNICAL FIELD The present invention relates to a gas turbine combustor designed to be x and an operating method thereof.

[0002]

2. Description of the Related Art In a combustion region where the equivalence ratio of fuel and air is close to 1.0, the combustion temperature locally rises and a large amount of NOx is generated.
Therefore, the premixed lean combustion method with a reduced equivalence ratio is adopted as a means for suppressing the generation of NOx. However, since combustion is unstable only with this combustion method, it has been combined with the diffusion combustion method. The staged combustion method is adopted.

A conventional gas turbine combustor to which the two-stage combustion system is applied is disclosed in, for example, Japanese Patent Laid-Open No. 2-309123.

The gas turbine combustor 1 is constructed as shown in FIG. 9, and is arranged between a gas turbine (not shown) and the compressor 2. The discharge air compressed by the compressor 2 is guided to the combustion chamber 4 in the combustor liner 3 of the gas turbine combustor 1, mixed with fuel in the combustion chamber 4 and burned, and the combustion gas is transferred to the transition piece 5. It guides to a gas turbine through and drives this gas turbine to work.

The gas turbine combustor 1 is attached to a gas turbine casing 6 via a sleeve casing 7, and a head plate 8 is attached to a flange portion of the sleeve casing 7. A flow sleeve 9 for guiding the discharge air from the compressor 2 is provided between the head plate 8 and the sleeve casing 7.

A diffusion burn type pilot burner 10 is attached to the head plate 8, and a premixed lean burn type main burner 11 is provided on the outer peripheral portion of the pilot burner 10.

The pilot burner 10 is provided at its tip with a swirler 12 for stirring the air discharged from the compressor 2, and the swirler 12 is inserted into the head ring 13 of the combustor liner 3. Fuel A to the pilot burner 10 is supplied by a pilot fuel supply pipe (not shown) connected to the outer flange 14.

On the other hand, the main burner 11 is a premixed lean burn type burner, which is opposed to the fuel injection nozzles 15 of the pilot burner 10 which are provided on the outer peripheral side at equal pitches in the circumferential direction and the fuel injection side of this fuel injection nozzle 15. And a premixing pipe 16 arranged in the same manner.

The premixing pipe 16 is arranged between the combustor liner 3 and the flow sleeve 9, and a premixed fuel injection port 16 a which is divided into three parts is inserted into the combustor liner 3. Fuel is supplied to the inlet of the premixing pipe 16 from a fuel supply pipe 18 connected to the outside of the head plate 8 through a fuel injection nozzle 15, and a fuel B of a different system from the pilot burner 10 is supplied.

On the other hand, the discharge air C compressed by the compressor 2 flows between the combustor liner 3 and the flow sleeve 9,
A part of the cooling air C1 cools the combustor liner 3, and a part of the remaining cooling air C2 serves as the combustion air C2.
Of the swirler 12, is agitated with the fuel A injected from the pilot burner 10, and burns in the combustion chamber 4.

Further, the remaining discharge air is premixed air C.
3 flows in from the inlet of the premixing pipe 16. The inflowing premixed air C3 is premixed with the fuel B injected from the fuel injection nozzle 15 to become a premixed lean fuel, and the injection port 16
It is ejected from a to the combustion chamber 4 and burns. The premixed lean combustion of the main burner 11 is performed by the pilot burner 1 on the upstream side.
The combustion is maintained with the help of the flame holding function by the combustion of zero.

[0012]

PROBLEM TO BE SOLVED BY THE INVENTION Pilot burner 10
There is a conventional gas turbine combustor that employs a two-stage combustion system that combines diffuse combustion in the main burner 11 and premixed lean combustion in the main burner 11. This two-stage combustion system is Although this is an excellent combustion method that can achieve a significantly low NOx, further reduction of NOx is desired from the viewpoint of environmental protection.

NOx is generated by the reaction of nitrogen and oxygen in the air during the combustion process of fuel, and its generation largely depends on the local combustion temperature and the residence time in the temperature field. Therefore, in order to reduce NOx, it is effective means to lower the local combustion temperature as low as possible and to shorten the residence time in the temperature field.

In order to shorten the residence time, it is effective to make the gas turbine combustor 1 small to increase the flow velocity of the combustion gas, but at the same time, the combustion load factor becomes high and the metal temperature of the combustor liner 3 increases. Therefore, the cooling air flow rate of the gas turbine combustor 1 must be increased. Therefore, when the combustion air decreases or when the combustion air cannot be decreased, the metal temperature of the gas turbine combustor 1 becomes higher than the planned value, and damage or life of the gas turbine combustor 1 is reduced. Will cause a decline.

On the other hand, when the combustion temperature is lowered, the generation of NOx decreases exponentially. For example, when the fuel is natural gas,
Depending on the variation in the fuel composition, the combustion temperature will be N700 when the combustion temperature rises above 1700 ° C.
Ox starts to increase rapidly, and when it becomes lower than this temperature, it becomes N
Ox hardly occurs. Of course, the residence time may also be affected, but in the gas turbine combustor 1 used for a normal gas turbine, the residence time hardly affects in this temperature range.

Premixed lean combustion is a combustion system in which fuel and air are premixed before combustion and the premixed equivalence ratio is burned at 1.0 or less, but the equivalence ratio is 1700 ° C.
By selecting a value that does not exceed, it is possible to suppress the generation of NOx to an extremely low level.

Even in the above-described two-stage combustion system of diffusion combustion / premixed lean combustion, the equivalent ratio of premixing is selected so that the combustion temperature in premixed lean combustion does not exceed 1700 ° C. under the rated load condition. Therefore, almost no NOx is generated in this combustion, and most NOx generation in this two-stage combustion method depends on diffusion combustion.

Therefore, in order to reduce NOx, the ratio of the fuel flow rate to be used for diffusion combustion and premixed lean combustion is N
As little as possible on the diffusion combustion side where Ox is generated, NO
It is important to increase the amount on the premixed lean combustion side where x is rarely generated and to switch the fuel from the diffusion combustion to the premixed lean combustion on the low load side as much as possible.

First, the ratio of the fuel flow rate used for diffusion combustion and premixed lean combustion will be described. Since the flame temperature of the premixed lean combustion is low, the premixed lean combustion alone may cause misfire, or unstable combustion may occur even if the misfire does not occur, resulting in combustion oscillation and a large amount of CO. . Therefore, in order that the premixed lean combustion can maintain a stable combustion state, it is necessary to form a high-temperature combustion region by diffusion combustion and play a role of a flame holding function for the premixed lean combustion. For this reason, the ratio of the fuel flow rate to diffusion combustion cannot be made too low.

Next, the fuel switching from diffusion combustion to premixed lean combustion will be described.

Needless to say, if the switching is performed on the low load side as much as possible, it is possible to reduce the generation of NOx in the partial load that maximizes the switching point. Since the amount of fuel supplied to the diffusion combustion is small, the high-temperature combustion region formed by the diffusion combustion becomes narrow, and the flame holding function of the premixed lean combustion cannot be fully exerted.

As shown in FIG. 10, in the premixed lean combustion, the equivalence ratio of the premixed fuel becomes too low,
In combination with the narrow high-temperature combustion region, the premixed lean combustion causes misfiring or unstable combustion even if the misfiring does not occur, resulting in combustion oscillation, CO
Occurs in large quantities. Therefore, in order to maintain a stable combustion state in the premixed lean combustion, it is necessary to supply the minimum amount of fuel flow to the diffusion combustion, and it becomes impossible to switch the fuel on the low load side.

The premixed lean combustion method is an excellent combustion method as a means for reducing NOx, but it has the possibility of flashback in the premixing pipe, and if such a flashback phenomenon occurs, a serious accident will occur. As a result, the reliability of operation of the gas turbine is significantly reduced. Flashback occurs when the flow velocity of the premixed fuel becomes lower than the flame propagation velocity under the conditions of fuel composition, temperature, and equivalence ratio. For this reason, it is important to make the flow velocity in the premixing pipe faster than the flame propagation velocity, and further, in the premixing pipe 16, a smooth region where a region lower than the flame propagation velocity does not occur is generated. Shape is required.

As described above, most of NOx is generated by diffusion combustion, but since the proportion of the fuel flow rate used for diffusion combustion is large, the amount of NOx generated, including partial load, is still at a high level. The reduction of NOx in the turbine combustor 1 is not always sufficient.

When the fuel is switched from the pilot burner 10 to the main burner 11, the main burner 11
Is low, and CO may be generated or unstable combustion may occur at this time, which is not always sufficient in terms of operation reliability due to low CO and stable combustion. Further, even if the average flow velocity in the premixing pipe 16 is set to be higher than the flame propagation velocity, a region where the velocity is locally generated locally and the margin against flashback is not always sufficient.

The present invention has been made in consideration of the above-mentioned circumstances, and suppresses the generation of NOx and CO to an extremely low level in the entire load zone including the rated load and the partial load of the gas turbine, and performs the entire operation. An object of the present invention is to provide a highly reliable gas turbine combustor capable of maintaining a stable combustion state in a region and performing stable operation for a long time, and an operating method thereof.

Another object of the present invention is to provide a premixing tube with a margin against flashback of premixed lean combustion, to facilitate fuel control, to perform stable operation for a long period of time, and to reduce NOx and CO. (EN) Provided is a highly reliable gas turbine combustor and its operating method.

[0028]

In order to solve the above problems, a gas turbine combustor according to the present invention has a combustor liner housed in a combustor housing casing as set forth in claim 1. A main burner and a pilot burner are respectively provided in the head portion of the combustor liner, and the pilot burner is composed of a diffusion combustion burner and a plurality of premixed lean combustion burners arranged on the outer peripheral portion of the diffusion combustion burner.

In order to solve the above-mentioned problems, the gas turbine combustor according to the present invention has a premixed lean burner as described in claim 2, in which a fuel injection nozzle and fuel injection of this fuel injection nozzle are provided. And a premixing pipe installed facing each other, the premixing pipe has a straight tubular shape from the inlet portion to the middle of the pipe, the cross-sectional area smoothly decreases as it approaches the jet outlet, and the jet outlet is The premixed lean burner is arranged such that the main burner is curved in a tangential direction on the circumference of the pilot burner with a required inclination angle, and the main burner is arranged on the outer peripheral portion of the pilot burner. In the main burner, a plurality of fuel injection nozzles and a premixing pipe installed to face the fuel injection side of these fuel injection nozzles are multiply arranged around the combustor liner on the inner peripheral side and the outer peripheral side. Premixed tube on the outer peripheral side The ejection port is located downstream of the ejection port of the premixing pipe on the inner peripheral side, and further, as described in claim 4, the premixing pipe of the main burner has a straight tubular shape from the inlet portion to the middle of the pipe, The cross-sectional area decreases smoothly as it approaches the jet, and the axis of the jet connected to the cone-shaped head of the combustor liner is formed so as to be substantially perpendicular to the liner surface of the combustor liner. is there.

Further, in order to solve the above problems, in the gas turbine combustor according to the present invention, as described in claim 5, a fuel pressure control valve and a fuel flow rate control valve are sequentially installed in the turbine fuel supply system. , The turbine fuel supply system is branched from the downstream side of the fuel flow control valve into the pilot fuel supply system and the main fuel supply system, while the branched pilot fuel supply system is supplied from the downstream side of the pilot fuel distribution valve to the fuel for diffusion combustion. The system and the premixed lean combustion fuel supply system are branched and connected to each fuel pipe of the pilot burner, while the premixed lean combustion fuel supply system is provided with an on-off valve and a flow rate adjusting orifice. The other main fuel supply system is branched from the downstream side of the main fuel distribution valve into a plurality of premixed lean fuel supply systems and connected to each fuel pipe of the main burner, The premixed lean fuel supply system to be supplied to the fuel injection nozzle arranged in the circumferential side on - in which off valve and flow adjustment orifice is provided.

In order to solve the above-mentioned problems, the method of operating a gas turbine combustor according to the present invention is, as described in claim 6, in the process of igniting a gas turbine and diffusing the pilot burner during the process of increasing the rotation. Only the combustion burner is operated, and before the gas turbine reaches the no-load rated speed, a part of the pilot fuel supply system is switched so that the pilot burner operates both the diffusion combustion burner and the premixed lean combustion burner. In the load zone from no load to the required low load of the gas turbine, the combustion state in which both burners of the pilot burner are burned is continued, and the gas turbine with the required low load is located on the inner peripheral side of the main burner. Operate the injection nozzles and operate both the pilot burner and the main burner in the load range from the required low load to the intermediate load of the gas turbine. Further, the gas turbine operates the fuel injection nozzles arranged on the outer peripheral side of the main burner at the required intermediate load to operate the fuel injection nozzles arranged on the inner peripheral side and the outer peripheral side, and the gas turbine operates from the required intermediate load. The load zone up to the rated load is the operating method of the gas turbine combustor that operates by operating all fuel supply systems of the pilot burner and the main burner.

Further, in order to solve the above-mentioned problems, the method of operating a gas turbine combustor according to the present invention, as set forth in claim 7, before the gas turbine reaches the no-load rated speed, the pilot. When the premixed lean burn burner of the burner is operated, the equivalence ratio in the premixing pipe is larger than the minimum equivalence ratio at which the generation of CO rapidly increases. When operating the fuel injection nozzles arranged on the circumferential side, immediately before switching, the equivalence ratio in the premixing pipe of the pilot burner is NO.
The generation ratio of x is smaller than the equivalence ratio that rapidly increases, and immediately after switching, the equivalence ratio in the premixing pipe of the pilot burner and the equivalence ratio in the premixing pipe located on the inner peripheral side of the main burner are Is larger than the equivalence ratio that rapidly increases, and when the gas turbine operates the fuel injection nozzles arranged on the outer peripheral side of the main burner at the required intermediate load, the gas turbine is moved to the inner peripheral side of the main burner immediately before switching. The equivalence ratio in the premixing pipes arranged is smaller than the equivalence ratio in which the generation of NOx suddenly increases, and immediately after switching, the equivalence ratios in the premixing pipes arranged on the inner and outer peripheral sides of the main burner. Are both larger than the equivalence ratio at which CO generation increases rapidly, and are arranged on the inner and outer peripheral sides of the main burner when the gas turbine is at the rated load. The equivalence ratio in the premixing pipe is smaller than the equivalence ratio in which the generation of NOx increases rapidly, and the pilot burner uses a gas turbine with almost constant fuel in the load range from the required low load operation to the rated load operation. A method of operating a gas turbine combustor in which fuel is controlled so as to maintain a flow rate.

[0033]

In the gas turbine combustor of the present invention, a pilot burner and a main burner are respectively provided in the head portion of the combustor liner, while the pilot burner is provided with a diffusion combustion burner and a plurality of preliminary burners arranged on the outer peripheral portion of the diffusion combustion burner. Since the pilot burner has two burners of diffusion combustion and premixed lean burn, it is equipped with a mixed lean burn burner. By adjusting the combustion state in the gas turbine combustor with this pilot burner and the main burner, the gas turbine is controlled. NOx in the full load range including the rated load and partial load of
Is maintained at a very low level, a stable combustion state is maintained in all operating regions, stable operation can be secured for a long time, and reliability is high.

Further, while the pilot burner is provided with a premixed lean burner, the main burner is a premixed lean burner, and the main burner is arranged to face the fuel injection side of the fuel injection nozzle of each premixed lean burner. The mixing tube is claim 2.
According to the present invention, the flow velocity of the premixed lean fuel flowing in the premixing pipe can be constantly maintained at a speed higher than the fire propagation speed, the flashback phenomenon can be prevented, and the premixed lean combustion can be prevented. The premixing tube can have a tolerance against flashback, and fuel control is easy and stable operation can be secured for a long time.

According to the method of operating the gas turbine combustor, only the diffusion combustion burner of the pilot burners is operated during the process of ignition and rotation increase of the gas turbine, but this diffusion combustion has an excellent flame holding function. The rotation of the gas turbine is increased while maintaining a stable combustion state. Before the gas turbine reaches the unloaded rated speed,
By switching a part of the pilot fuel system, the pilot burner operates two systems of a diffusion combustion burner and a premixed lean burner.

Immediately after switching a part of the pilot fuel supply system, the fuel flow rate supplied to the diffusion combustion burner decreases, but the minimum fuel flow rate for stable combustion of the diffusion combustion burner is secured, This state is maintained even when the gas turbine reaches the unloaded rated speed.
Therefore, in comparison with the conventional pilot burner which uses only diffusion combustion, the flow rate of the fuel supplied to the diffusion combustion burner is significantly reduced in this pilot burner.
Since Ox decreases almost in proportion to the fuel flow rate, NOx reduction has already been achieved in the no-load operation state. Since the premixed lean burn burner of the pilot burner is installed on the outer circumference of the diffusion burner, the flame of diffusion combustion has a flame holding function against the lean lean burn of premixing. Since the generation of CO is larger than the equivalence ratio that rapidly increases, the generation of CO is small and a stable combustion state can be obtained.

When the fuel flow rate to the pilot burner is increased, the fuel is proportionally increased in the diffusion combustion burner and the premixed lean combustion burner, and the gas turbine is in a load operating state.
When the gas turbine requires a low load, the main fuel supply system is operated, and a portion of the fuel supplied to the pilot burner is summed to the fuel injection nozzles arranged on the inner peripheral side of the main burner. Switch without changing and operate the main burner.

First, immediately after switching to the main burner, the flow rate of fuel supplied to the diffusion combustion burner of the pilot burner is much smaller than that of the conventional diffusion combustion only pilot burner.
The occurrence of x is greatly reduced. Also, since the equivalence ratio in the premixing pipe is smaller than the equivalence ratio at which the generation of NOx rapidly increases, NOx is greatly reduced for the pilot burner as a whole, and fuel switching between the pilot burner and the main burner during partial load operation is performed. The peak of NOx generation immediately before can be suppressed to an extremely low level.

Immediately after the switching, the flow rate of fuel supplied to the diffusion combustion burner of the pyro-burner is reduced, so that NOx is further reduced. The equivalence ratio in the premixing pipe of the pilot burner and the equivalence ratio in the premixing pipe located on the inner peripheral side of the main burner are set to be larger than the equivalence ratio at which CO generation increases rapidly. Maintains a combustion state almost the same as that during no-load operation and maintains a sufficient flame holding function against combustion of the main burner, so that the main burner can secure stable combustion.

In the region where the load is further increased, the fuel supply amount to the pilot burner is controlled so as to be a substantially constant value, so that the combustion state of the pilot burner hardly changes and this state is maintained up to the rated load. ing. At a certain intermediate load, the valve opening of the on-off valve in the fuel supply system of the main burner is changed from closed to open, and a part of the fuel supplied to the fuel injection nozzle arranged on the inner peripheral side of the main burner. Is switched to the fuel injection nozzle arranged on the outer peripheral side without changing the total amount, and the two systems of the main burner are operated.

Immediately before the switching, the equivalence ratio in the premixing pipe arranged on the inner peripheral side of the main burner is smaller than the equivalence ratio at which the generation of NOx rapidly increases. Therefore, NOx is hardly produced in the main burner. However, there is only a small amount of NOx generated in the pilot burner.

Immediately after the switching, since the equivalence ratios in the premixing pipes arranged on the inner peripheral side and the outer peripheral side of the main burner are both larger than the equivalence ratio at which the CO generation abruptly increases, the CO generation does not occur. It is rarely seen, and the flame holding function of the pilot burner allows the main burner to maintain a stable combustion state.

Further, when the load rises and the operating condition is the rated load, the equivalence ratio in the premixing tube of the main burner is N.
Since the generation of Ox is smaller than the equivalence ratio that increases rapidly,
Similar to the above, almost no NOx is generated in the main burner, and only a small amount of NOx is generated in the pilot burner, and the NOx generation in the combustor as a whole can be suppressed to an extremely low level.

[0044]

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

FIG. 1 shows an assembled cross section of the gas turbine combustor of the present invention, and FIG. 2 shows a vertical cross section of the gas turbine combustor shown in FIG. FIG. 3 is a sectional view taken along the line III-III of the gas turbine combustor shown in FIG.

The gas turbine combustor 20 is the gas turbine 2
1 and the compressor 22, and several or a dozen or more are arranged along the circumferential direction in a gas turbine casing 23 that also serves as a combustor housing casing. The gas turbine combustor 20 is attached to a gas turbine casing 23 via a head plate 24.

The gas turbine combustor 20 has a combustor liner 25 housed in a gas turbine casing 23. The combustor liner 25 defines a combustion chamber 26 in a conical head portion inside thereof, and a combustion gas mixing area 27 is formed on the downstream side of the combustion chamber 26. The combustion gas is passed through a transition piece 28 to a gas turbine. The gas turbine 21 is driven by being supplied to the inlet side of the gas turbine 21.

On the other hand, the combustor liner 25 is covered with a flow sleeve 30 attached to the inner peripheral flange of the gas turbine casing 23 on the side of the head plate 24, and an air flow is provided between the flow sleeve 30 and the combustor liner 25. A passage 31 is formed, and the discharge air C from the compressor 22 is guided to the air passage 31. A guide vane 32 is installed in the middle of the air flow path 31, and the discharge air C is guided by the guide vane 32.

A pilot burner 33 is installed on the center side of the head plate 24, and a main burner 34 is installed on the peripheral side thereof. The pilot burner 33 is plugged into the top ring 35 of the combustor liner 25 and has a diffusion combustion burner 36 and a plurality of premixed lean combustion burners 37 arranged around the diffusion combustion burner 36. 36 and the premixed lean burn burner 37 are mounted on a pilot burner flange which is a header disc 38.

The header disk 38 is the head plate 24.
Is fixed so as to cover the central opening of the above, a diffusion combustion burner 36 is installed in the inner central portion thereof, and a plurality of premixed lean combustion burners 37 are installed in the periphery thereof. Two fuel supply pipes 39, 4 with mounting flanges are provided on the outer side of the header disk 38.
0 is connected, of which the central fuel supply pipe 39 is a fuel supply pipe for diffusion combustion and communicates with the diffusion combustion burner 36 via the central flow passage in the header disk 38. The diffusion fuel burner pipe 41 of the diffusion combustion burner 36 is passed through a sleeve-shaped diffusion combustion air pipe 42. Discharge air C from the compressor 22 is guided through the flow sleeve 30 to the diffusion combustion air pipe 42, and a diffusion combustion swirler 43 for stirring the discharge air is attached to the tip thereof.

The other fuel supply pipe 40 is a fuel supply pipe for premixed lean combustion and is communicated with a torus-shaped fuel header 44 formed in the header disk 38. The fuel header 44 is connected to the premixed lean burner 37. Fuel injection nozzle 4
5 are communicated with each other. The premixed lean combustion burner 37 is composed of a fuel injection nozzle 45 and a premixing pipe 46 which is arranged so as to face the fuel injection side.

Premixing Premixing tube 46 of lean burn burner 37
Has a straight pipe shape from the inlet to the middle of the pipe, and has a spout 46a.
The cross-sectional area decreases smoothly toward. Each premixing pipe 46
The jet outlets 46a are arranged in the circumferential direction, and are curved with a required inclination angle in the tangential direction on the circumference where the jet outlets 46a are arranged.

Reference numeral 47 is a reinforcing plate for reinforcing the pilot burner 33.

Further, the main burner 34 located outside the pilot burner 33 is provided with two systems of premixed lean burners 50 and 51 on the inner peripheral side and the outer peripheral side, respectively.
A plurality of premixed lean burners 50, 51 of each system are provided at equal pitches along the circumferential direction.

Of these, the premixed lean burn burner 50 on the inner peripheral side has a fuel injection nozzle 53 attached to the head plate 24 and a premixing pipe 54 arranged so as to face the fuel injection side of this nozzle. Each fuel injection nozzle 53 communicates with a torus-shaped inner fuel header 55 formed in the head plate 24, and an inner fuel supply pipe 56 with a connection flange communicates with the inner fuel header 55 from the outside of the head plate 24. ing.

Further, the premixing pipe 54 has a straight tubular shape from the inlet portion to the middle of the pipe, and is curved as the approaching the ejection port 54a and the cross-sectional area is smoothly reduced. The jet port 54a of the premixing pipe 54 is connected to the cone-shaped head portion 25a of the combustor liner 25, and at this time, the axis of the jet port 54a of the premixing pipe 54 is substantially perpendicular to the liner surface of the combustor liner 25. Is formed.

On the other hand, the premixed lean burn burner 51 on the outer peripheral side
Also has a fuel injection nozzle 57 attached to the head plate 24, and a premixing pipe 58 installed facing the fuel injection side of the nozzle 57. Each fuel injection nozzle 57 communicates with a torus-shaped outer fuel header 59 formed in the head plate 24. An outer fuel supply pipe 60 with a connecting flange is connected to and communicates with the fuel header 59 from the outside of the head plate 24.

Further, the premixed lean burn burner 51 on the outer peripheral side is provided.
The pre-mixing tube 58 of is a straight tube from the inlet to the middle of the tube,
As it approaches the ejection port 58a, it is curved and the cross-sectional area is smoothly reduced, and it is connected to the cone-shaped head portion 25a of the combustor liner 25. The jet port 58a of each premixing pipe 58 is located downstream of the jet port 54a of the inner peripheral side premixing pipe 54, and the axis of the jet port 58a is substantially perpendicular to the liner surface of the combustor liner 25. It is formed.

The premixing tubes 46, 54 and 58 are supported by the premixing tube support ring 62 via brackets as appropriate. Reference numeral 63 is a combustor liner support fitting.

In the combustor liner 25, the inside of the cone-shaped head portion 25a is formed as a combustion chamber 26, and a combustion gas mixing area 27 continues to the downstream side of the combustion chamber 26.
A part of the air discharged from the compressor 22 is blown into the mixing area 27 as cooling air C ₁ .

A turbine fuel supply system 65 for supplying fuel to the gas turbine combustor 20 is constructed as shown in FIG. A turbine fuel supply system 65 to which fuel is supplied from a fuel supply device (not shown) has a fuel pressure control valve 66 and a fuel flow control valve 67, and a pilot fuel supply system 68 and a main fuel are provided downstream of the fuel flow control valve 67. It is branched to the supply system 69.

One of the branched pilot fuel supply systems 68 is arranged from the downstream side of the pilot fuel distribution valve 70 to the diffusion combustion fuel supply system 71 and the premixed lean combustion fuel supply system 7.
2 is connected to the diffusion combustion fuel supply pipe 39 and the premixed lean combustion fuel supply pipe 40 of the pilot burner 33. An on / off valve 73 and a flow rate adjusting orifice 74 are installed in the fuel supply system 72 for premixed lean combustion.

The other main fuel supply system 69 is branched from the downstream side of the main fuel distribution valve 75 into an inner premixed lean fuel supply system 76 and an outer premixed lean fuel supply system 77, and the inner fuel of the main burner 34 is separated. It is connected to the supply pipe 56 and the outer fuel supply pipe 60, respectively. The outer premixed lean fuel supply system 77 is provided with an on-off valve 78 and a flow rate adjusting orifice 79, respectively.

By the way, the gas turbine combustors 20 are arranged on the circumference of the gas turbine in a number of several or a dozen or more. Among them, two gas turbine combustors 20, 2 are provided.
There are two igniters 80, one for each 0 (see FIG. 3).
Is attached. Two flame detectors 81, one in total, are attached to each of the two gas turbine combustors different from the gas turbine combustor 20 to which the igniter 80 is attached,
Further, the flame propagation pipe 8 is provided between all the gas turbine combustors 20.
Two are provided.

When the gas turbine is started, the igniter 80 is operated to ignite the gas turbine combustor 20 provided with the igniter 80. A part of the combustion gas flows into the adjacent gas turbine combustor through the flame propagation tube 82 and is ignited, and thereafter, all the gas turbine combustors 20 are ignited sequentially. The ignition state of the gas turbine combustor is detected by the flame propagation pipe 81 to confirm the completion of ignition of the gas turbine.

Next, the operation of the gas turbine combustor will be described.

The compressor 22 is driven integrally with the gas turbine 21, and the discharge air C compressed by the driving of the compressor 22 passes between the combustor liner 25 and the flow sleeve 30 and is directed to the top of the combustor. Flow, part of which is cooling air C ₁
As a result, the combustor liner 25 is cooled and mixed into the combustion gas, and the rest is the pilot burner 33 and the main burner 3.
4 is supplied as combustion air.

On the other hand, the turbine fuel is supplied to the gas turbine combustor 20 from an external fuel supply device (not shown) and burned in the combustion chamber 26, and the high-temperature and high-pressure combustion gas D is transferred from the gas turbine combustor 20 to the transition piece 28. It is guided to the gas turbine 21 through and drives the gas turbine 21 to expand and work.

Turbine fuel from the external fuel supply system is
Specifically, the pilot burner 33 and the main burner 3
4 to the combustion chamber 26 of the combustor liner 25. Among them, the pilot burner 33 has a diffusion combustion burner 36 and a premixed lean combustion burner 37, and the diffusion combustion fuel is supplied to the diffusion combustion burner 36 via a diffusion combustion fuel supply pipe 39.

Diffusion combustion burner tube 4 of diffusion combustion burner 36
A swirler 43 for diffusion combustion is provided at one end, and a fuel injection port 41a is provided on an inner ring of the swirler 43. Fuel is ejected from the fuel injection port 43a, and the ejected fuel is diffused and burned by the combustion air sent to the air passage portion 80 formed by the diffusion combustion burner pipe 41 and the diffusion combustion air pipe 42 located outside thereof. The mixed swirler 43 mixes, diffuses, and blows it out, and burns in the combustion chamber 26. In the diffusion combustion, the flame holding region 81 is formed at the center of the combustion region due to the stirring effect of the swirler 43 for diffusion combustion, and therefore has a function of maintaining stable combustion by itself.

The premixed lean burn burner 37 is provided around the diffusion burner 36, and is provided with a plurality of premixed lean burn fuel injection nozzles 45 mounted inside the header disk 38. Premixed lean burner fuel is supplied from the premixed lean burn fuel supply pipe 40 through the fuel header 44.

The supplied fuel for the premixed lean burner is jetted from the nozzle port of the fuel injection nozzle 45 into the premixing pipe 46. The ejected fuel is mixed with premixing air in the premixing pipe 46 and ejected from the ejection port 46 a of the premixing pipe 46.

The premixed fuel jetted out is the diffusion fuel flame region 8
A swirl flow is formed so as to enclose the flame of No. 2 and the diffusion combustion flame at the center plays a flame holding function against this premixed lean combustion. Therefore, the premixed lean burner 37 of the pilot burner 33 can maintain stable combustion.

By the way, since the premixing pipe 46 of the premixed lean burner 37 needs a length for sufficiently mixing the fuel and air, the diffusion combustion burner pipe 41 inside the premixed lean burner 37 is required. Becomes longer. In order not to reduce the rigidity of this diffusion combustion burner pipe 41, several reinforcing plates 47
Is fixed to the header disk 38, and the diffusion combustion burner tube 4 is
1 and the diffusion combustion air pipe 42 are joined.

On the other hand, in the main burner 34, the plurality of premixing pipes 54 are arranged on the inner peripheral side, and the other premixing pipes 58 are arranged on the outer peripheral side in the circumferential direction at equal pitches on the circumference, and the combustion is performed. It is located around the vessel liner 25. The injection port 54a of the premixing pipe 54 on the inner peripheral side is provided on the upstream side of the combustion chamber 26,
The injection port 58a of the premixing tube 58 on the outer peripheral side is inserted into the combustor liner 25 so as to be located immediately downstream thereof.

The premixing tubes 54 and 58 are attached to the supporting metal 8
4 are pinned to each two brackets 85 of a premix tube support ring 62 mounted to the top (head) of the combustor liner 25.

Like the fuel injection nozzle 45 of the pilot burner 33, the head plate 24 has a main burner 34.
Also, several fuel injection nozzles 53, 57 for premixed lean combustion are attached to the inner and outer circumferences, and the tip portions of these fuel injection nozzles respectively correspond to the premixing tubes 54, 58.
Is inserted at the entrance of the.

Inside the head plate 24, a torus-shaped inner fuel header 55 and an outer fuel header 59 are doubly provided, and the respective headers 55, 59 communicate with the fuel injection nozzles 53, 57. The inner and outer fuel headers 55 and 59 are connected to the outer and inner fuel supply pipes 56 and 60 of the head plate 24. Fuel for the premixed lean burn burner of the main burner 34 is supplied through these inner and outer fuel supply pipes 56 and 60.
The supplied fuel is ejected from the fuel injection nozzles 53 and 57 into the premixing pipes 54 and 58, and the ejected fuel is mixed with the premixing air in the premixing pipes 54 and 58, and the respective ejection ports 54a, It is ejected from the combustion chamber 26 from 58a.

The premixed fuel ejected from the inner premixing pipe 54 is directed to the combustion flame region of the pilot burner 33, and the ejected flows collide with each other at the center to decelerate and cooperate with the high temperature combustion atmosphere. Thus, a flame holding region for the premixed lean combustion of the main burner 34 can be formed in this region, and the premixed lean combustion can maintain stable combustion.

The premixed lean combustion in the outer premixing tube 58 has the same combustion mode as above, and the premixed fuel injected from the premixing tube 58 has a high temperature combustion region forming an upstream flame holding region. Since this is ejected to, it is possible to maintain stable combustion.

FIG. 5 shows the flow velocity distribution in the premixing pipes 46, 54 and 58 of the pilot burner 33 and the main burner 34. The cross-sectional area of the premixed fuel decreases and the flow velocity becomes faster as it approaches the injection port, and the pipe internal flow velocity is faster than the flame propagation velocity throughout the premixing pipes 46, 54, 58, and is locally decelerated because of the circular pipe shape. It has no area and has sufficient tolerance against flashback.

On the downstream side of the combustion area of the main burner 34, there is a combustion gas mixing area 27 in which the combustion gases of the pilot burner 33 and the main burner 34 and the cooling air C1 of the combustor liner 25 are mixed. Combustion gas D
Is guided to the gas turbine 21 through a transition piece 28 provided on the downstream side.

Further, the gas turbine combustor 20 is provided with several combustor liner support fittings 63 on the circumference of the top of the combustor, and the support rods 63a protruding from the flow sleeve 30 are attached to the combustor liner support fittings 63. Be fitted. The position of the combustor liner 25 is determined by inserting the end of the combustion gas mixing area 27 into the transition piece 28 located downstream of the combustor liner 25. The flow sleeve 30 is arranged coaxially with the combustor liner 25, and is attached to the gas turbine casing 23. The guide vanes 32 provided on the inner circumference of the flow sleeve 30 allow the discharge air to flow along the outer surface of the combustor liner 25 on the upper side thereof and cool the combustor liner 25.

A fuel supply system for supplying turbine fuel to the gas turbine combustor 20 is constructed as shown in FIG. In this fuel supply system 65, a fuel pressure control valve 66 and a fuel flow rate control valve 67 are provided from the upstream side, and the fuel supply system 65 downstream of the fuel flow rate control valve 67 supplies the pilot burner 33 with a pilot fuel supply system 68. And a main fuel supply system 69 for supplying to the main burner 34.

A pilot fuel distribution valve 70 is attached to the pilot fuel supply system 68, and a main fuel distribution valve 75 is attached to the main fuel supply system 69.

The pilot fuel supply system 68 is located downstream of the pilot fuel distribution valve 70, and again the diffusion fuel supply system 71 is provided.
And two systems 71 and 72 of a premixed lean fuel supply system 72
And one diffusion fuel supply system 71 is connected to each gas turbine combustor 20 via a fuel manifold pipe 86.
The fuel for diffusion combustion is supplied by being connected to the fuel supply pipe 39 of the diffusion combustion burner 36. The other premixed lean fuel supply system 72 is also provided with the fuel manifold pipe 86,
It has the same function. Premixed lean fuel supply system 72
Is provided with an on-off valve 73 and a flow rate adjusting orifice 74, which is connected to the fuel supply pipe 40 of the premixed lean burner 37 to supply the premixed lean fuel. Fuel distribution to the diffusion combustion burner 36 and the premixed lean combustion burner 37 is set in advance by the flow rate adjusting orifice 74.

The main fuel supply system 69 is also branched into two premixed lean fuel supply systems 76 and 77 on the downstream side of the main fuel distribution valve 75. One is the inner fuel supply pipe 5
Connected to 6 to supply premixed lean fuel. Like the pilot fuel supply system 68, the other premixed lean fuel supply system 77 is provided with an on-off valve 78 and a flow rate adjusting orifice 79, and the premixed lean fuel supply pipe 60 is provided.
To supply premixed lean fuel. In this premixed lean fuel supply system 76, 77, fuel distribution to the fuel injection nozzles 53, 57 is similarly set.

In the gas turbine combustor 20, the pilot burner 33 and the diffusion combustion burner 35 are used.
And a premixed lean burn burner 37, and the main burner 34 has two systems of the premixed lean burn burner 5
Since 0 and 51 are provided, these pilot burners 33
The main burner 34 and the main burner 34 have the effect of realizing low NOx and low CO.

FIGS. 6 (A) and 6 (B) show the operation plan of the equivalence ratio to the gas turbine load and the fuel flow rate in the operation of the gas turbine, and FIG. 7 shows the gas turbine load and the generation of NOx and CO. It shows a relationship.

The gas turbine 21 operates only the diffusion combustion burner 36 of the pilot burners 33 during the process of ignition and rotation up, but this diffusion combustion has an excellent flame holding function and maintains a stable combustion state. The rotation of the gas turbine 1 is increased.

Before the gas turbine 21 reaches the unloaded rated speed, the fuel supply system 72 of the pilot burner 33.
The opening degree of the on-off valve 73 is changed from closed to open, and a part of the fuel supplied to the diffusion combustion burner 36 is switched to the premixed lean combustion burner 37 without changing the total fuel flow rate. Burner 33 and diffusion combustion burner 36
And two systems 71 and 72 of the premixed lean burner 37 are operated.

Immediately after the fuel is switched, the diffusion combustion burner 36
Although the flow rate of fuel supplied to the
6 has a minimum flow rate for stable combustion,
This state is maintained even when the gas turbine 21 reaches the unloaded rated speed. Therefore, in comparison with the conventional pilot burner that only uses diffusion combustion, the flow rate of fuel supplied to the diffusion combustion burner 36 is significantly reduced in this pilot burner 33, and NOx is, as shown in FIG. Since it decreases almost in proportion to the fuel flow rate, the NOx reduction has already been achieved in the no-load operation state.

Since the premixed lean burner 37 is provided on the outer circumference of the diffusion burner 36, the flame of the diffused combustion has a flame holding function against the premixed lean burn, and further the premixed lean fuel burns. Since the equivalence ratio is larger than the equivalence ratio at which CO generation rapidly increases, CO generation is small and a stable combustion state can be obtained.

When the fuel flow rate to the pilot burner 33 is increased, the diffusion combustion burner 36 and the premixed lean burner 3
The fuel supplied to No. 7 increases proportionally to enter the load operation state. When the gas turbine 21 has a required low load, a part of the fuel supplied to the pilot burner 33 is switched to the fuel injection nozzle 53 arranged on the inner peripheral side of the main burner 34 without changing the total fuel flow rate. The main burner 34 is operated.

Immediately before switching to the main burner 34, the fuel flow rate supplied to the diffusion combustion burner 36 of the pilot burner 33 is much smaller than that of the conventional pilot burner of only diffusion combustion. The generation of NOx from 36 is greatly reduced. Further, the equivalence ratio in the premixing pipe 46 of the pilot burner 33 is smaller than the equivalence ratio at which the generation of NOx sharply increases, so the NOx of the pilot burner 33 as a whole is greatly reduced, and it is The peak of NOx generation immediately before fuel switching of the pilot burner 33 and the main burner 34 can be suppressed to an extremely low level.

Immediately before switching to the main burner 34, the flow rate of fuel supplied to the diffusion combustion burner 36 of the pilot burner 33 decreases, so that NOx further decreases. At this time, the diffusion combustion burner 36 secures the minimum fuel flow rate for stable combustion. The equivalence ratio in the premixing pipe 46 of the pilot burner 33 and the equivalence ratio in the premixing pipe 54 arranged on the inner peripheral side of the main burner 34 are CO
Is larger than the equivalence ratio that rapidly increases, and the pilot burner 33 maintains almost the same combustion state as during no-load operation. Since it retains its function, the main burner 34 can ensure stable combustion.

Further, in the region where the turbine load of the gas turbine 21 is increased, the fuel supply amount to the pilot burner 33 is controlled to be a substantially constant value, so that the combustion state of the pilot burner 33 hardly changes, This state is maintained until rated load operation. At a required intermediate load, the valve opening degree of the on-off valve 78 in the fuel supply system 77 of the main burner 34 is changed from closed to open, and the fuel injection nozzle 5 arranged on the inner peripheral side of the main burner 34 is opened.
A part of the fuel supplied to No. 3 is switched to the fuel injection nozzle 57 arranged on the outer peripheral side without changing the total amount, and the two systems 76 and 77 of the main burner 34 are operated.

Immediately before switching to the outer peripheral side of the main burner 34, the equivalence ratio in the premixing pipe 54 arranged on the inner peripheral side of the main burner 34 is smaller than the equivalence ratio at which the generation of NOx rapidly increases. , NOx in the main burner 34
Is hardly generated, and only a small amount of NOx is generated in the pilot burner 33.

Immediately before switching, the premixing tubes 54, 5 arranged on the inner and outer peripheral sides of the main burner 34 are arranged.
Since both of the equivalence ratios of 8 are larger than the equivalence ratio at which CO generation rapidly increases, almost no CO generation is observed,
Further, the flame holding function of the pilot burner 33 allows the main burner 34 to maintain a stable combustion state.

Further, when the turbine load of the gas turbine 21 increases and the load is rated, the main burner 3
Since the equivalence ratio of both premixing pipes 54 and 58 of No. 4 is smaller than the equivalence ratio at which the generation of NOx sharply increases, similar to the above, only NOx is produced in the main burner 34,
Generation of NOx can be suppressed to an extremely low level in the gas turbine combustor 20 as a whole.

Thus, this gas turbine combustor 20
The pilot burner 33 is installed in the gas turbine 21.
Before the engine reaches the no-load rated speed, most of the diffusion combustion fuel is switched to the premixed lean combustion fuel, and the distribution of the fuel flow rate does not change even in the load operation. Among the pilot burners 33, the fuel flow rate supplied to the diffusion combustion burner 36 can be significantly reduced as compared to the fuel flow rate supplied to the conventional pilot combustion only for diffusion combustion. Therefore, NOx hardly occurs in premixed lean combustion, most of it occurs in diffusion combustion, and
Considering that NOx is generated almost in proportion to the flow rate of the fuel supplied to the diffusion combustion burner 36, compared with the conventional combustion operation of the pilot burner only by diffusion combustion, the generation of NOx by the combustion in the pilot burner 33 is generated. Can be suppressed to an extremely low level over the full load operation range.

Compared to the turn-down ratio of the conventional pilot burner using only diffusion combustion, this pilot burner 33
Then, the turn-down ratio of the diffusion combustion burner 36 can be reduced because the fuel flow rate is small in the load operation region. Therefore, the fuel injection differential pressure of the diffusion combustion burner 36 can be made sufficiently high, so that a stable combustion state can be obtained in a wide operating range from the start of the gas turbine 21 to a partial load, and further the generation of CO can be reduced. can do.

When the fuel is switched, for example, the gas turbine 21
Before reaching the no-load rated speed, the pilot burner 33 switches from diffusion combustion to premixed lean combustion, the combustion state of the pilot burner 33 at a certain low load switches to combustion of the main burner 34, and the main burner By switching from one system to two systems of premixed lean combustion at 34
1 is stopped), the switching is reversed. Including the switching, the gas turbine combustor 20 in the gas turbine combustor 20 includes the premixed lean combustion of the pilot burner 33 and the main burner 34. Equivalent ratio is N
Ox is smaller than the air-fuel ratio that suddenly occurs, and CO
Since the fuel flow rate is controlled so as to fall within a range larger than the equivalence ratio at which NOx rapidly occurs, the generation of NOx and CO due to premixed lean combustion is extremely small.

Therefore, in the full load range of the gas turbine 21 from no load to the rated load, this gas turbine combustor can realize low NOx and low CO. Since the premixed lean combustion of the pilot burner 33 burns so as to enclose the diffusion combustion flame, the flame holding function against the premixed lean combustion is good, and the stable combustion state of the premixed lean combustion of the pilot burner 33 is obtained. Main burner 3
The flame holding function is similarly good for the premixed lean combustion of No. 4, and the main burner 34 can maintain a stable combustion state.

Pilot burner 33 and main burner 34
There are two fuel supply systems each for a total of four systems. Compared to the conventional system, one on-off valve is provided for each of the pilot fuel supply system 68 and the main fuel supply system 69, for a total of two systems.
However, it is not a complicated fuel control valve but a valve that operates simply by opening and closing with signals of rotation speed, load or fuel flow rate, despite the fact that the fuel supply system has increased. The fuel control system does not become complicated and can maintain the same level as before. Therefore, the gas turbine 2
1 can be controlled without impairing the operation reliability.

[0106]

As described above, in the gas turbine combustor according to the present invention, the pilot burner and the main burner are respectively provided on the head portion of the combustor liner,
The pilot burner is provided with a plurality of premixed lean burners arranged on the outer periphery of the diffusion combustion burner. Since the pilot burner has two burners, diffusion combustion and premixed lean burn, the pilot burner and the main burner use gas. By adjusting the combustion state in the turbine combustor, NOx and CO generation are maintained at extremely low levels in all load zones including the rated load and partial load of the gas turbine, and stable in all operating regions. Maintain the burning state,
It can secure stable operation for a long time and is highly reliable.

Further, while the pilot burner is equipped with a premixed lean burner, the main burner is a premixed lean burner, and the main burner is arranged to face the fuel injection side of the fuel injection nozzle of each premixed lean burner. The mixing tube is claim 2.
According to the present invention, the flow velocity of the premixed lean fuel flowing in the premixing pipe can be always kept stable above the fire propagation speed, the flashback phenomenon can be prevented, and the premixed lean combustion can be prevented. The premixing tube can have a margin against flashback, the fuel can be easily controlled, and stable operation can be secured for a long time.

Further, according to this method of operating the gas turbine combustor, the process of increasing the rotation from the ignition of the gas turbine, the process of reaching the no-load rated speed of the gas turbine, and the no-load of the gas turbine to the required low load. Diffusion combustion burner and premixing of the pilot burner according to the process of the load zone from the low load to the intermediate load required by the gas turbine, and the process of the load zone from the required intermediate load to the rated load. Since the lean burn burner and the premixed lean burn burner on the inner and outer circumferences of the main burner were appropriately adjusted and controlled according to the operation plan, NOx and CO were generated in all load zones including the rated load and partial load of the gas turbine. Can be suppressed to an extremely low level, and NOx and CO can be reduced. Even with this reduction in NOx and CO, it is possible to maintain a stable combustion state in the entire operating range and guarantee stable operation for a long period of time.

Further, the equivalence ratio of the premixed lean fuel guided in the premixing pipe of the premixed lean burner used in the pilot burner or main burner of the gas turbine combustor is from the start of the gas turbine to the rated operating state. Until,
Since the pilot burner has a sufficient flame holding function against the combustion of the main burner, the main burner can ensure stable combustion and the low N
Ox and CO can be reduced, and when the load on the gas turbine rises and the load is at the rated load, the equivalence ratio in both premixing tubes of the main burner is equivalent to the amount at which NOx generation rapidly increases. Since the ratio is smaller than the ratio, almost no NOx is generated in the main burner, and only a small amount of NOx is generated in the pilot burner, and the NOx generation can be suppressed to an extremely low level in the gas turbine combustor as a whole.

[Brief description of drawings]

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

2 is a vertical cross-sectional view of the gas turbine combustor shown in FIG.

3 is a cross-sectional view taken along the line III-III of the gas turbine combustor shown in FIG.

FIG. 4 is a system configuration diagram showing a fuel supply system to a gas turbine combustor according to the present invention.

FIG. 5 is a diagram showing the relationship between the in-pipe flow velocity in the premixing pipe used in the gas turbine combustor of the present invention and the flame propagation velocity.

FIG. 6A is a diagram showing a relationship between a turbine load and an equivalence ratio (air-fuel ratio) during gas turbine operation, and FIG. 6B is a diagram showing a relationship between a turbine load and a fuel flow rate.

FIG. 7 is a diagram showing the NOx amount and CO amount with respect to the gas turbine load of the gas turbine combustor of the present invention in comparison with the NOx amount and CO amount of the conventional gas turbine combustor.

FIG. 8 is a diagram showing the relationship between the generation of NOx and CO in the gas turbine combustor and the equivalence ratio.

FIG. 9 is a vertical sectional view showing a conventional gas turbine combustor.

10 (A) and 10 (B) are diagrams showing a plan of an equivalence ratio and a fuel flow rate in the operation of the gas turbine in the conventional gas turbine combustor, respectively.

[Explanation of symbols]

 20 Gas Turbine Combustor 21 Gas Turbine 22 Compressor 24 Head Plate 25 Combustor Liner 26 Combustion Chamber 27 Combustion Gas Mixing Region 30 Flow Sleeve 31 Air Flow Path 33 Pilot Burner 34 Main Burner 36 Diffusion Combustion Burner 37 Premixed Lean Burner 38 Header disk 39 Fuel supply pipe for diffusion combustion 40 Fuel supply pipe for premixed lean combustion 41 Diffusion fuel burner pipe 42 Air pipe for diffusion combustion 43 Diffusion combustion swirler 44 Fuel header 45,53,57 Fuel injection nozzle 46,54,58 Premixing pipe 50,51 Premixed lean burner 55 Inner fuel header 56 Inner fuel supply pipe 59 Outer fuel header 60 Outer fuel supply pipe 65 Turbine fuel supply system 66 Fuel pressure control valve 67 Fuel flow control valve 68 Pilot fuel supply system 69 Main fuel supply System 70 Pilot fuel distribution valve 71 Diffusion combustion fuel supply system 72 Premixed lean combustion fuel supply system 73, 78 On-off valve 74, 79 Flow rate adjustment orifice 75 Main fuel distribution valve 76 Inner premixed lean fuel supply system 77 Outside Premixed lean fuel supply system 80 Ignition device 81 Flame detector 82 Flame propagation tube

Claims (7)

[Claims] 1. A combustor liner is housed in a combustor housing casing, and a main burner and a pilot burner are provided at a head portion of the combustor liner. The pilot burner is a diffusion combustion burner and an outer peripheral portion of the diffusion combustion burner. A gas turbine combustor characterized by comprising a plurality of premixed lean burners arranged in the. 2. A premixed lean combustion burner has a fuel injection nozzle and a premixing pipe installed so as to face the fuel injection side of the fuel injection nozzle, and the premixing pipe extends from the inlet portion to the middle of the pipe. The gas according to claim 1, which is in the shape of a straight tube, the cross-sectional area of which decreases smoothly as it approaches the ejection port, and which is curved with a required inclination angle in the tangential direction on the circumference where the ejection port is arranged. Turbine combustor. 3. The main burner is a premixed lean combustion burner arranged on the outer peripheral portion of the pilot burner, and the main burner is installed so as to face a plurality of fuel injection nozzles and the fuel injection side of these fuel injection nozzles. A premixing tube is placed around the combustor liner in multiple layers on the inner and outer peripheral sides,
The gas turbine combustor according to claim 1, wherein the injection port of the premixing pipe on the outer peripheral side is located downstream of the injection port of the premixing pipe on the inner peripheral side. 4. The premixing pipe of the main burner has a straight tubular shape from the inlet to the middle of the pipe, the cross-sectional area of which is reduced smoothly as it approaches the ejection port, and it is connected to the cone-shaped head of the combustor liner. The gas turbine combustor according to claim 1, wherein an axis of the jet port is formed so as to be substantially perpendicular to a liner surface of the combustor liner. 5. A fuel pressure control valve and a fuel flow control valve are sequentially installed in the turbine fuel supply system, and the turbine fuel supply system is branched from a downstream side of the fuel flow control valve into a pilot fuel supply system and a main fuel supply system. The branched pilot fuel supply system is branched from the downstream side of the pilot fuel distribution valve to the diffusion combustion fuel supply system and the premixed lean combustion fuel supply system and connected to each fuel pipe of the pilot burner. An on-off valve and a flow control orifice are installed in the fuel mixture system for mixed lean combustion, while the other main fuel supply system is branched from the downstream side of the main fuel distribution valve into a plurality of premixed lean fuel supply systems. The premixed lean fuel supply system connected to each fuel pipe of the main burner and supplied to the fuel injection nozzle arranged on the outer peripheral side has an on-off valve and a flow adjustment orifice. A gas turbine combustor characterized in that the gas turbine combustor is provided. 6. In the process from ignition to rising of rotation of the gas turbine, only the diffusion combustion burner of the pilot burner is operated, and a part of the pilot fuel supply system is switched before the gas turbine reaches the no-load rated rotation speed. Then, the pilot burner operates both the diffusion combustion burner and the premixed lean burner, and the combustion state in which the burner burns both burners of the pilot burner in the load range from no load to the required low load of the gas turbine, The gas turbine operates the fuel injection nozzle located on the inner peripheral side of the main burner at the required low load, and the load range from the required low load to the intermediate load of the gas turbine is set at both the pilot burner and the main burner. In operation, the gas turbine operates the fuel injection nozzle located on the outer peripheral side of the main burner at the required intermediate load. The fuel injection nozzles on the inner and outer circumferences are operated together, and the gas turbine is operated by operating all fuel supply systems of the pilot burner and the main burner in the load range from the required intermediate load to the rated load. Characteristic gas turbine combustor. 7. When the premixed lean burn burner of the pilot burner is operated before the gas turbine reaches the no-load rated speed, the equivalence ratio in the premixing pipe is the minimum equivalence which causes a rapid increase in the generation of CO. When the gas turbine is operated by switching the fuel injection nozzle located on the inner peripheral side of the main burner at the required low load, the equivalence ratio in the premixing pipe of the pilot burner immediately before switching. Is smaller than the equivalence ratio at which the generation of NOx suddenly increases. Immediately after switching, the equivalence ratio in the premixing pipe of the pilot burner and the equivalence ratio in the premixing pipe arranged on the inner peripheral side of the main burner are If the gas turbine operates a fuel injection nozzle arranged on the outer peripheral side of the main burner at a required intermediate load, the generation ratio is larger than the equivalence ratio that rapidly increases. , Before switching straight, the equivalent ratio of the premixed tube is disposed on the inner peripheral side of the main burner N
The generation ratio of Ox is smaller than the equivalence ratio that rapidly increases, and immediately before switching, the equivalence ratios in the premixing pipes arranged on the inner peripheral side and the outer peripheral side of the main burner both rapidly increase CO generation. The equivalence ratio is larger than the equivalence ratio, and the equivalence ratio in the premixing pipes located on the inner and outer circumference sides of the main burner is smaller than the equivalence ratio at which the NOx generation increases rapidly when the gas turbine is at the rated load. In addition, the pilot burner performs fuel control so that the gas turbine maintains a substantially constant fuel flow rate in the load range from the required low load operation to the rated load operation. .