JP2001153363A - Gas turbine combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas turbine combustor which is contrived to reduce the occurrence of NOx and can improve the service life of gas turbine equipment by preventing the intrusion of a frame into a premixing duct. SOLUTION: For the gas turbine combustor having at least two or more fuel systems from which fuel is supplied at variable quantities when the combustor is operated, a lower limit is provided for the minimum fuel flow rate when the fuel is supplied to the system to which the fuel is supplied at the maximum flow rate.

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 air and fuel for combustion, and more particularly to a gas turbine combustor for reducing the amount of NOx generated.

[0002]

2. Description of the Related Art In recent years, gas turbine combustors applied to recent thermal power plants employ lean premixed combustion in order to achieve environmental pollution regulation values of NOx concentration. . In lean premixed combustion, the amount of NOx emitted is small because fuel and air are mixed and burned in a fuel-lean state in advance, but the mixture range in which stable and low NOx combustion is performed is narrow. To the rated load. For this reason,
A multi-stage combustion system in which the number of fuel control systems is increased is employed.

[0003] As a multi-stage combustion system, for example, there is a gas turbine employing a two-stage system. FIG. 5 schematically shows a gas turbine combustor having two fuel systems.

As shown in FIG. 5, a fuel system is provided on the upstream side of the combustor liner 1 having a cylindrical shape.
Diffusion fuel system 2 for introducing diffusion fuel a into combustor liner 1
And a premixed fuel system 3 for introducing the premixed fuel b into the combustor liner 1.

The diffusion fuel system 2 includes a diffusion fuel pipe 4 for supplying diffusion fuel a from a fuel supply source (not shown). The diffusion fuel pipe 4 is provided at the center of the upstream side of the combustor liner 1 for diffusion combustion. Connected to pilot nozzle 5. Then, the diffusion fuel a is introduced into the combustor liner 1 through the pilot nozzle 5.

On the other hand, the premixed fuel system 3 has a premixed fuel pipe 6 for introducing fuel from a fuel supply source (not shown). A premixing duct 7 for mixing air and fuel in advance is provided on the outer peripheral side of the combustor liner 1. A premixing combustion main nozzle 8 provided in the center of the premixing duct 7 on the upstream side is provided. The mixed fuel pipe 6 is connected. And
The premixed fuel “b” is supplied to the combustor liner 1 through the nozzle 8.
Supplied to

In the fuel system of the gas turbine combustor having such a configuration, the diffusion fuel a is introduced via the diffusion combustion pilot nozzle 5 in a small load range such as at the time of ignition or at night when the power supply is small. Secure the flame.
Further, when the load on the gas turbine increases, the throttle of the diffusion combustion pilot nozzle 5 is adjusted to reduce the amount of diffusion fuel a introduced, and the premix fuel b is supplied from the premix combustion main nozzle 8.

[0008] By employing such a two-stage system, the premixed fuel b stably performs lean premixed combustion by the type of diffusion flame, so that the generation of NOx can be suppressed.

In order to further reduce the amount of NOx generated, it is effective to reduce the proportion of fuel supplied to diffusion combustion. However, if the kind of fire is small, the flammability deteriorates when the premixed flame is thin. Therefore, in order to improve the combustibility, the premixed fuel system 3 was divided into two systems. FIG. 6 shows another example of the multistage combustion system using the control system of the gas turbine combustor. Since FIG. 6 is almost the same as FIG. 5, the same parts are denoted by the same reference numerals and the description is omitted.

As shown in FIG. 6, the premixed fuel system 3
A first premixed fuel system 9 for introducing the premixed fuel b from the outer peripheral surface of the fuel unit liner 1 and a premixed fuel b from an upstream side of the combustor liner 1 and near the diffusion fuel introduction unit. And a second premixed fuel system 10. The first premixed fuel system 9 is the same as the premixed fuel system 3 shown in FIG.

In the second premixed fuel system 10, a small premixed duct 11 is provided on the outer peripheral side of the diffusion combustion pilot nozzle 5 upstream of the combustor liner 1. A pilot nozzle 12 for premixed combustion is provided upstream of the small premixed duct 11, and the pilot nozzle 12 for premixed combustion is connected to a premixed fuel pipe 13 for supplying fuel from a fuel supply source (not shown). You. Then, the premixed fuel b also enters the fuel liner 1 from the second premixed fuel system 10.
Is supplied.

In the gas turbine combustor having such a fuel system, fuel is not supplied from the first premixed fuel system 9 in a range where the load during operation of the gas turbine is small, and the diffusion combustion pilot nozzle 5 Pilot nozzle 12 for the premixed combustion of the second premixed fuel system 10 with the diffusion flame of
To introduce and burn the premixed fuel b.

On the other hand, in the range where the load is large, the diffusion fuel a is introduced from the diffusion fuel system 2 and the premixed fuel b is introduced from the second premixed fuel system 10. Then, the premixed fuel b introduced from the first premixed fuel system 9 is stably burned by these flames.

As described above, the first and second premixed fuel systems 9 and 10 are operated in response to a change in load during operation of the gas turbine.
NOx generation can be further reduced by changing the fuel supply amount from the fuel cell.

[0015]

However, the premixed combustion as described above is effective in suppressing the generation of NOx, but the flame easily propagates in the premixed gas and the flame in the combustor liner 1 Penetrates into the premixing ducts 7 and 11,
Once invaded, there is a problem that the walls of the ducts 7 and 11 are burned.

As described above, in order to prevent the flame in the combustor liner 1 from entering the ducts 7 and 11, the injection speed of the premixed fuel b gas is made sufficiently higher than the speed at which the flame propagates. ing. However, in spite of such a contrivance, a problem that a flame invades the ducts 7 and 11 was often observed.

The present invention has been made to solve such a problem, and aims to reduce the amount of NOx generated, prevent a flame from entering the premixing duct, and improve the product life. An object is to provide a turbine combustor.

[0018]

In order to achieve the above object, the present inventors have investigated in detail the mechanism by which a flame in a combustor enters a duct.

Normally, when the ratio of the diffusion fuel a and the premixed fuel b is shifted from the state of multi-stage premix combustion to the direction in which the diffusion fuel a decreases, a flame is generated when the diffusion fuel a becomes smaller than a certain ratio. It becomes unstable, and the premixed fuel a repeats misfire and reignition. The pressure change in the combustor liner 1 at that time is such that the pressure decreases due to rapid volume reduction at the time of misfire, and conversely, the pressure increases at the time of re-ignition due to explosive combustion. When the pressure rise at the time of this reignition is large, the high-temperature gas in the combustor liner 1 instantaneously flows back into the premixed ducts 7 and 11 to ignite the premixed fuel b, and the combustion in the premixed ducts 7 and 11 is started. The cause was clarified by the study of the present inventors. The present invention has been completed based on such knowledge.

That is, the invention according to claim 1 provides a gas turbine combustor having at least two or more fuel systems for one combustor, and having a variable fuel supply amount from each system during operation. Is characterized in that when fuel is supplied to a system having a maximum fuel flow rate, a lower limit of the minimum fuel flow rate is set.

According to a second aspect of the present invention, there is provided a gas turbine combustor having at least three or more fuel systems for one combustor and having a variable fuel supply from each system during operation. When fuel is supplied to the system having the highest flow rate, the lower limit of the minimum fuel flow rate is set to be a function of the fuel flow rate which is the second lowest after the minimum fuel flow rate.

The invention according to claim 3 is the invention according to claim 1 or 2
The gas turbine combustor as described, wherein the fuel is a diffusion fuel or a premixed fuel.

According to a fourth aspect of the present invention, in the gas turbine combustor according to the first aspect, the lower limit of the minimum fuel flow rate is a function of the atmospheric temperature.

According to a fifth aspect of the present invention, in the gas turbine combustor according to the first aspect, the lower limit of the minimum fuel flow rate is a function of the compressor discharge temperature.

According to a sixth aspect of the present invention, in the gas turbine combustor according to the first aspect, the lower limit of the minimum fuel flow rate is a function of the atmospheric humidity.

According to a seventh aspect of the present invention, in the gas turbine combustor according to the second aspect, the lower limit of the minimum fuel flow rate is set to be a function of the fuel flow rate and the ambient temperature which are the second lowest fuel flow rate. And

According to an eighth aspect of the present invention, in the gas turbine combustor according to the second aspect, the lower limit of the minimum fuel flow rate is a function of the fuel flow rate and the compressor discharge temperature that is the second lowest fuel flow rate after the minimum fuel flow rate. It is characterized by.

According to a ninth aspect of the present invention, in the gas turbine combustor according to the second aspect, the lower limit of the minimum fuel flow rate is a function of the fuel flow rate and the atmospheric humidity which are the second lowest fuel flow rate and the second lowest fuel flow rate. And

According to a tenth aspect of the present invention, in the gas turbine combustor according to the first or second aspect, the fuel flow rate is measured and controlled.

According to an eleventh aspect of the present invention, in the gas turbine combustor according to the first or second aspect, control is performed by a valve opening signal of a flow control valve provided in each fuel system instead of actually measuring the fuel flow rate. Features.

In the case of multistage premixed combustion in which there are two or more fuel systems, when the fuel is supplied to the system having the largest fuel flow rate, it is preferable to set a lower limit for the minimum fuel flow rate. For example, when diffusion fuel and premixed fuel are used as the fuel, that is, when the fuel systems 2 and 3 shown in FIG. 5 of the conventional example are provided, the high-temperature gas in the combustor liner 1 It is necessary to prevent misfiring and reignition of the premixed fuel b in order to prevent the premixed fuel b from igniting the premixed fuel by flowing backward. More specifically, the misfire / reignition of the premixed fuel a can be avoided by introducing and operating the diffusion fuel a at or above the lower limit flow rate so that the premixed fuel b shown in FIG. 5 does not cause misfire / reignition. .

It has been experimentally found that the limit flow rate of repetition of misfire and re-ignition of the premixed fuel b varies depending on the temperature and humidity of the combustion air. In a gas turbine, since the temperature of combustion air is the compressor discharge temperature, the amount of NOx generated is reduced by changing the lower limit of the flow rate of the diffusion fuel a according to the compressor discharge temperature.
The flame can be prevented from entering the premixing ducts 7 and 11.
Further, since the compressor discharge temperature is a function of the atmospheric temperature, the atmospheric temperature may be used as a numerical value for control. Further, since the humidity of the combustion air is the same as the atmospheric humidity, the lower limit of the flow rate of the diffusion fuel is changed according to the atmospheric humidity to reduce the amount of NOx generated and prevent the flame from entering the duct.

Next, a gas turbine combustor having three or more fuel systems will be described. In the case of such multistage premixed combustion, the ratio of the three fuel systems was varied from the normal premixed combustion state, and the distribution in which unstable combustion of misfiring and reignition occurred was investigated. The premixed fuel system supplying the maximum flow rate is defined as the first system, and the fuel system having the minimum fuel flow rate is defined as the second system.
The third system was the system with the second lowest fuel flow after the system. The relationship between the two is shown on the graph of FIG. 7 with the second fuel flow rate on the horizontal axis and the third fuel flow rate on the vertical axis. Note that the horizontal axis represents the second fuel flow rate and the vertical axis represents the third fuel flow rate.

As shown in FIG. 7, the misfire / reignition limit line 13
Is obtained as one curve, and this misfire re-ignition limit line 1
It has been experimentally found that 3 is divided into an unstable combustion range and a stable combustion range. From this experimental fact, in order to prevent the flame from entering the premixing duct due to a sudden change in pressure due to misfiring and reignition, the second fuel flow rate and the third fuel flow rate are adjusted and unstable combustion is performed. It is necessary to keep out of the area.

Further, it has been experimentally found that the fuel flow range limit line 13 of the second system and the third system in which misfire and re-ignition are repeated changes depending on the temperature and humidity of the combustion air. In a gas turbine, the temperature of the combustion air is the compressor discharge temperature. For this reason, by changing the lower limit of the flow rate of the diffusion fuel in accordance with the compressor discharge temperature, it is possible to reduce the amount of generated NOx and to prevent the flame from entering the duct. Since the compressor discharge temperature is a function of the atmospheric temperature, the atmospheric temperature may be used as a numerical value for control. Furthermore, since the humidity of the combustion air is the same as the atmospheric humidity, the lower limit of the flow rate of the diffusion fuel is changed according to the atmospheric humidity,
It is possible to reduce the amount of generated NOx and to prevent the flame from entering the premix duct.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

First Embodiment (FIGS. 1 and 2) In this embodiment, a gas turbine combustor having two fuel systems will be described with reference to FIGS.

FIG. 1 is a view schematically showing a gas turbine combustor provided with two fuel systems and provided with means for controlling the fuel flow rate in these fuel systems.

As shown in FIG. 1, a fuel system is provided upstream of the cylindrical combustor liner 20. The fuel system is a diffusion fuel system 2 for introducing the diffusion fuel a into the combustor liner 20.
1 and a premixed fuel system 22 for introducing a premixed fuel b into the combustor liner 20.

The diffusion fuel system 21 is provided with a diffusion fuel pipe 23 for supplying the diffusion fuel a into the combustor liner 20 from a fuel supply source (not shown), and the flow rate of introducing the diffusion fuel a into the diffusion fuel pipe 23 is adjusted. Diffusion fuel flow control valve 24
Is provided. The downstream end of the diffusion fuel pipe 23 is connected to a diffusion combustion pilot nozzle 25 provided at the center of the upstream side of the combustor liner 20, and the diffusion fuel a is supplied through the pilot nozzle 25 into the combustion liner 20. Will be introduced.

On the other hand, the premixed fuel system 22 is provided with a premixed fuel pipe 26 for supplying fuel from a fuel supply source (not shown). A mixed fuel flow control valve 27 is provided.
Downstream of the premixed fuel pipe 26 is a combustor liner 20.
Is connected to a premixing duct 28 arranged on the outer peripheral side of the combustor liner 20. Supplied to

Each of the fuel systems 21 and 22 is provided with means for controlling the amount of fuel a and b introduced. As a control means, the flow control valve 24 of the diffusion fuel system 21 includes:
A diffusion fuel opening degree setting device 30 for detecting and adjusting the opening degree of the flow rate control valve 24 to adjust the flow rate of the diffusion fuel a is connected. This diffusion fuel opening degree setting device 30 is connected to a minimum opening signal transmitter 31 for transmitting the lower limit amount for introducing the diffusion fuel a.

On the other hand, the flow control valve 2 of the premixed fuel system 22
Similarly, a premix fuel opening degree setting device 32 that detects and adjusts the opening of the flow control valve 27 to vary the flow rate of the premix fuel b is connected to 7. The premixed fuel opening degree setting device 32 is connected to the diffusion fuel opening degree setting device 30, and the premixed fuel b
The flow rate of the diffusion fuel a can be varied in accordance with the flow rate fluctuation of.

FIG. 2 shows the minimum opening signal transmitter 3 shown in FIG.
FIG. 1 is a diagram schematically showing a gas turbine combustor in which a sensor 33 and a function calculator 34 are connected.

As shown in FIG. 2, the sensor 33 detects the atmospheric temperature, the compressor discharge temperature or the atmospheric humidity, and the lower limit opening obtained from the detected sensor signal is calculated by the function calculator 34. A signal is transmitted to the opening signal transmitter 31.

In the gas turbine combustor having such a fuel system, the diffusion combustion pilot nozzle 2
5 to introduce a diffusion fuel a to secure a flame. And
When the load on the gas turbine increases, the amount of diffusion fuel a supplied from the diffusion combustion pilot nozzle 25 is reduced, and the premix fuel b is introduced from the premix combustion main nozzle 29. With the introduction of the premixed fuel b, the diffused fuel opening degree setting unit 30 receives a signal from the premixed fuel opening degree setting unit 32 that the premixed fuel opening degree is not zero. When receiving this signal, based on the signal from the minimum opening signal transmitter 31,
The fuel flow of the diffusion fuel b is controlled so as not to fall below the lower limit.

During operation of the gas turbine, particularly in a low load range where the amount of power supply is small, such as at night, the supply of the premixed fuel b is reduced by the signal from the premixed fuel opening degree setting device 32 to reduce the ignition time. Similarly, the flame is secured by introducing the diffusion fuel a.

According to the present embodiment, the premixed fuel b is changed by opening and closing the flow control valves 24 and 27 by the signals of the opening degree setting devices 31 and 32 according to the load of the gas turbine to change the fuel introduction amount. In addition, since lean premix combustion is performed stably by the type of diffusion flame, NOx generation can be suppressed.

A sensor 33 for detecting the atmospheric temperature, compressor discharge temperature or atmospheric humidity shown in FIG. 2 is installed, and the amount of fuel introduced into the combustor liner 20 is varied based on a function obtained from this signal. Thus, the optimum lower limit value is always given to the combustion condition, the flame is prevented from entering the premixing duct 28, and the life of the gas turbine combustor can be improved.

In this embodiment, the fuel flow rate signal is not picked up, and the flow rate is controlled by signals from the opening degree transmitters 30, 31, and 32. Instead of the opening degree transmitters 30, 31, 32, as another embodiment, a flow meter is provided in each of the fuel systems 21, 22 to measure the fuel flow rate, and the measured value is fed back to each of the fuel systems 21, 22. By doing so, the fuel flow rate may be controlled. Further, the opening degree transmitters 30, 31, 3
2 may be controlled based on a signal from the flowmeter 2 and an actual measurement value from the flow meter, and the setting accuracy of setting devices provided in the fuel systems 21 and 22 can be further improved.

Further, in this embodiment, although there are two fuel systems, a sturbine combustor is shown.
The present invention is not limited to the system, and can be applied to a gas turbine combustor having two or more fuel systems.

Second Embodiment (FIGS. 3 and 4) In this embodiment, a gas turbine combustor having three fuel systems will be described with reference to FIGS. FIG. 3 is a view obtained by dividing the premixed fuel system 22 of FIG. 1 according to the first embodiment, and has substantially the same configuration as that of FIG. I do.

FIG. 3 is a view schematically showing a gas turbine combustor provided with three fuel systems and provided with means for controlling the fuel flow rate in the fuel system.

As shown in FIG. 3, the premixed fuel system 22
Is a first premixed fuel system 35 for introducing the premixed fuel b from the outer peripheral surface of the fuel liner 20 and a premixed fuel b from the vicinity of the diffusion fuel introduction portion on the upstream side of the combustor liner 20. And a second premixed fuel system 36 to be introduced.

The first premixed fuel system 35 is the same as the premixed fuel system 22 of the first embodiment shown in FIG.

The second premixed fuel system 36 is provided with a premixed fuel pipe 37 for supplying a premixed fuel b into the combustor liner 20 from a fuel supply source (not shown). A premix fuel flow control valve 38 for controlling the flow of b is provided. The downstream side of the premixed fuel pipe 38 is connected to a small premixed duct 39 disposed on the outer peripheral side of the combustor liner 20.
The premixed fuel b is introduced into the combustor liner 20 via a premixed combustion pilot nozzle 40 installed at the upstream center of the combustor.

Each fuel system 21, 35, 36 is provided with means for controlling the amount of fuel a, b introduced.

As a control means, similarly to the fuel system shown in FIG. 1 of the first embodiment, the diffusion fuel system 21 is connected to the diffusion fuel opening setting device 30 and the diffusion fuel opening setting device 30. A minimum opening signal transmitter 31. Further, the first premixed fuel system 35 includes a premixed fuel opening degree setting device 32.

On the other hand, the flow control valve 38 of the second premixed fuel system 36 detects and adjusts the opening of the flow control valve 38 and adjusts the flow rate of the premixed fuel b to set the premixed fuel opening. Device 41 is connected. This premix fuel opening degree setting device 41
Is connected to the minimum opening signal transmitter 31 of the diffusion fuel system 21 and the premix fuel opening degree setting device 32 of the first premix fuel system 35, so that the flow rate fluctuation of the premix fuel b can be controlled. Accordingly, the flow rate of the diffusion fuel a can be changed.

FIG. 4 shows the minimum opening signal transmitter 3 shown in FIG.
FIG. 1 is a diagram schematically showing a gas turbine combustor having a fuel system to which a sensor 33 and a function calculator 34 are connected.

As shown in FIG. 4, the sensor 33 detects the atmospheric temperature, the compressor discharge temperature or the atmospheric humidity, and the lower limit opening obtained from the detected sensor signal is calculated by the function calculator 34. A signal is transmitted to the opening signal transmitter 31.

In the gas turbine combustor having such a fuel system, the premixed fuel b is supplied from the premixed combustion main nozzle 29 in a small load range where the power supply is relatively small, such as during ignition or at night. Instead, the premixed fuel b of the second premixed fuel system 36 is burned by the diffusion flame from the pilot nozzle 25 for diffusion combustion. In the range where the load is large, the premixed fuel b of the first premixed fuel system 35 is stably burned by the flame from the diffusion combustion pilot nozzle 25 and the premixed duct 39 of the second premixed fuel system 36. This achieves low NOx. In such a range where the load is large, the premixed fuel opening degree setter 41 receives the signal that the premixed fuel opening degree is not 0 from the premixed fuel opening degree setter 32 of the first premixed fuel system 35, and According to a signal from the opening signal transmitter 31, the flow rate of the diffusion fuel a is controlled so as not to fall below the lower limit. The minimum opening signal transmitter 31 receives the signal from the diffusion fuel opening setting device 30 and transmits the lower limit value of the premixed fuel b in the second premixed fuel system 36 according to a function contained therein.

The sensor 33 shown in FIG. 4 detects the atmospheric temperature, the compressor discharge temperature or the atmospheric humidity. The lower limit opening obtained from the signal detected by the sensor 33 is calculated by the function calculator 34 and a signal is transmitted to the minimum opening signal transmitter 31.

According to this embodiment, the sensor 3 for detecting the atmospheric temperature, the compressor discharge temperature or the atmospheric humidity shown in FIG.
3 is installed, and the amount of fuel introduced into the combustor liner 20 is varied by a function obtained from this signal. That is, the flow control valves 24, 27, 38 are opened and closed according to the signals of the opening degree setting devices 31, 32, 41 in accordance with the load of the gas turbine, and premixed into the first premixed fuel system 35 having the maximum fuel flow. When the fuel b is supplied, the lower limit of the flow rate of the premixed fuel b in the second premixed fuel system 36, which is the minimum fuel flow rate, is set as a function of the fuel flow rate of the diffusion fuel a in the diffusion fuel system 21. Since the optimum lower limit of the fuel flow rate is always given to the combustion conditions, it is possible to prevent the intrusion of the flame into the premixing duct 28, thereby improving the life of the gas turbine combustor.

In the present embodiment, the opening degree transmitter 3
Although the flow rate is controlled by signals from 0, 32, and 41 and the fuel flow rate signal is not picked up, as another embodiment, a flow meter for measuring the fuel flow rate is provided in each of the fuel systems 21, 35, and 36. The values measured by the meter are
The fuel flow rate may be controlled by feeding back to 35 and 36. Further, based on the signals from the opening degree transmitters 30, 32 and 41 and the measured values from the flow meter, each fuel system 2
It is also possible to further improve the setting accuracy of the setting devices provided in 1, 35 and 36.

In this embodiment, the gas turbine combustor having three fuel systems has been described.
The present invention is not limited to the system, and can be applied to a gas turbine combustor having three or more fuel systems.

[0067]

As described above, according to the present invention,
By changing the amount of fuel introduced according to the load of the gas turbine, NOx generation is reduced, and a lower limit of the flow rate of the fuel system on the ignition side is set, resulting from sudden pressure fluctuation due to misfiring and reignition of premixed fuel. To prevent the intrusion of flames into the premixing duct and prevent the premixing duct from burning.
The product life of the gas turbine combustor can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a gas turbine combustor according to a first embodiment of the present invention, which includes two fuel systems and a means for controlling a fuel flow rate in these fuel systems.

FIG. 2 is a schematic diagram showing a gas turbine combustor in which a sensor 33 and a function calculator 34 are connected to the minimum opening signal transmitter 31 shown in FIG.

FIG. 3 is a schematic view showing a gas turbine combustor according to a second embodiment of the present invention, which includes three fuel systems and a means for controlling a fuel flow rate in these fuel systems.

FIG. 4 is a schematic diagram showing a gas turbine combustor in which a sensor 33 and a function calculator 34 are connected to the minimum opening signal transmitter 31 shown in FIG. 3;

FIG. 5 is a schematic diagram showing a conventional gas turbine combustor provided with two fuel systems.

FIG. 6 is a schematic diagram showing a conventional gas turbine combustor provided with two fuel systems.

FIG. 7 is a graph showing a limit at which a flame becomes unstable when there are three or more fuel systems in the present invention.

[Description of Signs] 20 Combustor liner 21 Diffusion fuel system 22 Premixed fuel system 23 Diffusion fuel pipe 24 Diffusion fuel flow control valve 25 Diffusion combustion pilot nozzle 26 Premixed fuel pipe 27 Premixed fuel flow control valve 28 Premixed duct 29 Main nozzle for premixed combustion 30 Diffusion fuel opening setter 31 Minimum opening signal transmitter 32 Premixed fuel opening setter 33 Sensor 34 Function calculator 35 First premixed fuel system 36 Second premixed fuel System 37 Premixed fuel pipe 38 Premixed fuel flow control valve 39 Premixed duct 40 Premixed combustion pilot nozzle 41 Premixed fuel opening degree setting device a Diffusion fuel b Premixed fuel

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F23N 5/00 F23N 5/00 U F23R 3/30 F23R 3/30 3/34 3/34 (72) Invention Person Yasunori Iwai 2-4-2 Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Keihin Works Co., Ltd. Person Yasuo Okamoto 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture F-term in Toshiba Keihin Works (reference) 3K003 EA07 FA01 FA07 FB05 3K065 TA01 TA13 TA18 TA12 TB12 TB13 TC08 TF01 TN01 TN03 TN10 TN11

Claims (11)

[Claims] 1. A gas turbine combustor having at least two or more fuel systems for one combustor and having a variable fuel supply amount from each system during operation, the system having the largest fuel flow rate A gas turbine combustor having a minimum fuel flow lower limit when fuel is supplied. 2. A gas turbine combustor having at least three or more fuel systems for one combustor and varying the amount of fuel supplied from each system during operation, the system having the largest fuel flow rate A gas turbine combustor characterized in that when fuel is supplied, the lower limit of the minimum fuel flow rate is a function of the next lowest fuel flow rate. 3. The gas turbine combustor according to claim 1, wherein the fuel is a diffusion fuel or a premixed fuel. 4. The gas turbine combustor according to claim 1, wherein the lower limit of the minimum fuel flow rate is a function of the atmospheric temperature. 5. The gas turbine combustor according to claim 1, wherein a lower limit of the minimum fuel flow rate is a function of a compressor discharge temperature. 6. The gas turbine combustor according to claim 1, wherein the lower limit of the minimum fuel flow rate is a function of the atmospheric humidity. 7. The gas turbine combustor according to claim 2, wherein the lower limit of the minimum fuel flow rate is a function of the fuel flow rate and the ambient temperature which are the second lowest fuel flow rate. . 8. The gas turbine combustor according to claim 2, wherein the lower limit of the minimum fuel flow rate is a function of the fuel flow rate and the compressor discharge temperature which are smaller than the minimum fuel flow rate. Combustor. 9. The gas turbine combustor according to claim 2, wherein the lower limit of the minimum fuel flow rate is a function of the fuel flow rate and the atmospheric humidity next to the minimum fuel flow rate. . 10. The gas turbine combustor according to claim 1, wherein the fuel flow rate is measured and controlled. 11. The gas turbine combustor according to claim 1, wherein the fuel flow rate is controlled by a valve opening signal of a flow control valve provided in each fuel system instead of actually measuring the fuel flow rate. vessel.