JP2002201966A - Premixing combustor for gas turbine and its fuel supply control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a premixing combustor for a gas turbine and its fuel supply control method having a multiple fuel supply system which can make sure ignition and rise up and realize low NOx and high combustion efficiency in a almost full operating range of 20 to 100% load regardless of changing of an air intake condition. SOLUTION: A pilot part having a pilot nozzle 26 is arranged in the center of a combustor 2. In an annular primary premixed gas passage 27 having a primary fuel nozzle 24, its inflow hole 27a into its combustion chamber is arranged downstream from an opening part 23a of the pilot nozzle 26. In an annular secondary premixed gas passage 28 having a secondary fuel nozzle 25, its inflow hole 28a into its combustion chamber is arranged downstream further from the opening part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a premix combustor for a gas turbine in which the concentration of nitrogen oxides (NOx) in exhaust gas is reduced, and a fuel supply control method therefor.

[0002]

2. Description of the Related Art In a conventional combustor for a gas turbine, diffusion combustion capable of obtaining stable combustion is used, so that the adiabatic flame temperature has reached about 2000 ° C. Therefore, even when a fuel having a low nitrogen component, such as natural gas, is used as fuel, it is inevitable that so-called thermal NOx is generated due to oxidation of nitrogen in the air.

[0003] Since this thermal NOx can be reduced by lowering the flame temperature, instead of diffusion combustion, the fuel is preliminarily mixed with combustion air to make a lean mixed gas, which is burned at a relatively low temperature. A technique for suppressing the generation of NOx by performing mixed combustion has been attempted.

[0004] However, when the fuel gas becomes lean, there is a problem that the stable combustion range is narrowed, and it is difficult to reliably ignite and stably burn. To solve this problem,
Japanese Patent Application Laid-Open No. 63-217141 discloses a technique in which diffusion combustion and premix combustion are used in combination, and the premix combustion is stabilized by controlling the flow rate of combustion air according to the load.

Further, Japanese Patent Application Laid-Open Nos.
JP-A-340273 and JP-A-8-128636 disclose an ignition gas ejection hole at the center and primary and secondary combustion premixed gas ejection holes provided concentrically around the ignition gas ejection hole. A technology has been disclosed in which by controlling the supply, a combustion device having a relatively simple structure can perform premixed combustion from ignition to stable combustion, thereby achieving low NOx.

[0006]

However, in the case of such a combustor having a large number of fuel supply systems, since the combustion spaces are separated, there is a problem that the combustion space at the time of ignition is narrow and the ignitable range is narrow. . If the ignitable range is narrow and ignition does not take place, a large amount of premixed gas may flow into the combustor without forming a flame, and may cause deflagration when ignited. It was necessary to perform advanced combustion control in the ignition system in order to prevent ignition and to ensure ignition without ignition delay and subsequent smooth acceleration.

In the conventional premixed combustor, fluctuations in intake conditions (pressure and temperature) are not taken into consideration. For example, NOx is reduced only in the operating range of 70 to 100% load.
Although low NOx properties below 0 ppm have been achieved, it has been difficult to achieve low NOx and high combustion efficiency over a wide operating range.

Accordingly, the present invention enables reliable ignition and start-up, and despite the change in intake conditions, the load 20 to
An object of the present invention is to provide a premixed combustor for a gas turbine having a multi-system fuel supply system capable of realizing low NOx and high combustion efficiency in almost the entire operation range of 100% and a fuel supply control method therefor. .

[0009]

In order to solve the above-mentioned problems, a premixed combustor for a gas turbine according to the present invention comprises a pilot portion having a pilot nozzle disposed at the center of the combustor, and a pilot portion provided at an outer peripheral portion thereof. A primary premixed gas passage having a primary fuel nozzle disposed therein, and a secondary premixed gas passage having a secondary fuel nozzle disposed further around the primary premixed gas passage,
A fuel supply system that is branched and connected to each of a pilot nozzle, a primary fuel nozzle, and a secondary fuel nozzle via a fuel cutoff valve, and that supplies fuel independently to each nozzle. In the mixed combustor, the inlet of the combustion chamber of the primary premixed gas passage is disposed downstream of the opening of the combustion chamber of the pilot section, and the inlet of the combustion chamber of the secondary premixed gas passage is further downstream thereof. A flow control valve is disposed in each of the branch passages to the primary fuel nozzle and the secondary fuel nozzle of the fuel supply system, and when a predetermined load or a turbine speed is higher, the pilot nozzle, the primary fuel nozzle, the secondary fuel nozzle, In addition to supplying fuel to all of the fuel nozzles, adjust the flow control valve that guides fuel to the secondary fuel nozzles according to load fluctuations, and adjust the intake conditions and turbine speed or negative speed. It is preferably provided with a fuel control system for regulating the flow rate control valve for guiding the fuel to the primary fuel nozzles in response to.

[0010] On the other hand, the fuel supply control method for a gas turbine premixed combustor according to the present invention comprises a fuel cutoff valve for controlling the pilot nozzle, primary fuel nozzle, and secondary fuel nozzle of the gas turbine premixed combustor. A fuel supply method for a gas turbine premixed combustor for supplying fuel by a fuel supply system branched and connected to each other, wherein the premixed combustor includes a pilot flame, a primary premixed flame, and a secondary premixed flame. A premixed combustor in which the next premixed flame is shifted from the upstream side to the downstream side to form a three-layer structure, and under a predetermined load or a condition of a turbine rotation speed or more, the pilot nozzle, the primary fuel nozzle, the secondary fuel While supplying fuel to all of the nozzles, the amount of fuel supplied to the secondary fuel nozzles is adjusted according to load fluctuations, and the amount of fuel supplied to the primary fuel nozzles is adjusted according to intake conditions. It is characterized in.

By arranging the opening of the combustion chamber of the pilot section and the inlet of the combustion chamber of each of the primary and secondary premixed gas passages as described above, a diffusion flame which becomes a fire at the upstream center of the combustion chamber, A primary premixed flame is formed on the outer periphery, a secondary premixed flame is further formed on the outer periphery of the primary premixed flame, and a flame is formed in three layers, so that a lean premixed gas which is normally difficult to burn can be reliably burned. Therefore, low NOx and high combustion efficiency can be realized, and reliable ignition and startup can be realized.

Since a three-layered flame is thus formed, it is easy to ensure the flame stability of each flame.
The method of supplying fuel to the fuel nozzle can be simplified, and the fuel supply amount can be easily adjusted. Furthermore, when the load is high, the fuel supply amount of the secondary fuel is adjusted in accordance with the load fluctuation, and the fuel supply amount of the primary fuel is adjusted in accordance with the intake condition and the turbine speed or the load, so that each of the fuel supply amounts is reduced with a lean air-fuel ratio. Since a stable flame can be formed while burning, it is possible to realize operation with low NOx and high combustion efficiency in a wide operation range.

In the premixed combustor according to the present invention, since the pilot flame is formed by a diffusion flame, it is possible to form a stable flame without being influenced by intake conditions without fine adjustment of the flow rate. . Therefore, it is preferable to simplify the configuration of the fuel supply system and improve reliability by arranging switching means for switching the fixed orifice and the fuel supply amount stepwise in the branch passage to the pilot nozzle of the fuel supply system. .

The premixed combustor for a gas turbine according to the present invention further includes a judging means for judging an ignition state of the pilot section based on a rise in turbine speed, exhaust gas temperature, pressure or load, and only fuel is supplied to the pilot nozzle at the time of starting. When the load or turbine speed is equal to or less than a predetermined value, it is preferable to adjust a flow control valve that guides fuel to the primary fuel nozzle according to the load variation.

On the other hand, in the fuel supply control method according to the present invention, at the time of starting, fuel is supplied only to the pilot nozzle, and its flow rate is adjusted by using a fixed orifice, so that the turbine speed, the exhaust gas temperature, the pressure, or the load are adjusted. The pilot fuel ignition is determined by the rise of the pilot fuel, and after the pilot fuel ignition is determined, the fuel supply to the primary fuel nozzle is started, and the fuel supply amount is increased to reduce the turbine rotational speed to the specified rotational speed. Increase
In load operation after reaching the specified turbine speed,
In the operating range below the predetermined load, the fuel supply to the secondary fuel nozzle is shut off, the fuel supply amount to the primary fuel nozzle is adjusted according to the load fluctuation, and when the load exceeds the predetermined load in the operating range. Preferably, the amount of fuel supplied to the pilot nozzle is increased.

Since the ignition of the pilot fuel can be reliably determined, it is possible to prevent a large amount of fuel from flowing into the combustor at the time of non-ignition, and it is possible to reliably prevent deflagration. In addition, after confirming the ignition of the pilot fuel, by shifting to acceleration control, it is possible to prevent the inflow of a large amount of unignited premixed air, reliably prevent deflagration, and suppress sudden acceleration after ignition. It is possible. Furthermore, even during light load operation, the spatial equivalence ratio in the combustion chamber can be maintained almost constant, and low NOx and low C
O combustion can be achieved over a wide operating range.

[0017]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In order to facilitate understanding of the description, the same constituent elements are denoted by the same reference numerals as much as possible in each drawing, and redundant description will be omitted.

FIG. 1 is a longitudinal sectional view showing a preferred embodiment of a premixed combustor for a gas turbine according to the present invention.
FIG. 2 is an end view of the combustor.

The combustor 2 is a can-type combustor having a substantially cylindrical inner cylinder 22 disposed inside a substantially cylindrical outer cylinder 21.
In FIG. 1, air compressed by a compressor 1 described later is guided from the right end to a space 21 a between the outer cylinder 21 and the inner cylinder 22 to reverse the flow, and is guided into the inner cylinder 22 for combustion. This is a backflow type combustor that flows out of the tank and is supplied to a turbine 3 described later. That is, the inside of the inner cylinder 22 forms a combustion chamber (hereinafter, referred to as a combustion chamber 22 as necessary).

In FIG. 1, three systems of fuel supply pipes L1 to L3, which will be described later, are connected to the left end inside the outer cylinder 21 and communicate with a pilot nozzle 23, a primary fuel nozzle 24, and a secondary fuel nozzle 25, respectively. . Here, the pilot nozzle 23 has an opening 23a at the center of the upstream side (indicating the left side of the figure) of the combustion chamber 22, and the ignition device 26 near the opening 23.
Is arranged. On the outer periphery of the pilot nozzle 23,
An annular air passage 26a having a turning plate 26s is formed. A plurality of primary fuel nozzles 24 are arranged around the outside of the air passage 26a, and an annular passage (hereinafter, referred to as a primary premix passage) 27 having a swirl plate 27s is arranged downstream thereof. The inflow hole 27a of the mixing passage 27 into the combustion chamber 22 is disposed downstream of the opening 23a of the pilot nozzle 23 in the flow direction. Also,
A plurality of secondary fuel nozzles 25 are arranged on the outer periphery of the primary fuel nozzle 24, and a swirl plate 28s
(Hereinafter referred to as a secondary premixing passage) 28
The inflow hole 28a of the secondary premix passage 28 into the combustion chamber 22 is provided with the inflow hole 27a of the primary premix passage 27.
It is arranged further downstream in the flow direction. As a result,
The opening 23a and the inflow holes 27a and 28a are arranged concentrically from the center of the combustion chamber 22, as shown in FIG.

FIG. 3 is a schematic diagram showing a gas turbine power generation system using the premixed combustor 2. Combustor 2
Is disposed between the compressor 1 and the turbine 3, injects fuel into the air compressed by the compressor 1 and burns it, and rotates the turbine 3 with the obtained high-temperature gas to obtain an output. For example, a generator 4 is connected to an output shaft of the turbine 3.

The above-described fuel supply lines L1 to L1 of the combustor 2
L3 is a part of the fuel supply system 6, and is branched and connected at a downstream side of a gas compressor 61 connected to a supply pipe of city gas and a shutoff valve 62 arranged at a downstream side thereof. The line L1 connected to the pilot nozzle 23 is further connected to two lines L10 and L11, each having fixed orifices 64 and 65 having different set flow rates, and connected again as one line on the downstream side. Have been. Here, the solenoid valve 63 is connected to the line L11.
Is arranged. Primary and secondary fuel nozzles 24, 2
Electromagnetic flow control valves 66 and 67 are arranged on the lines L2 and L3 connected to 5, respectively.

The controller 5 for controlling the operation of this system receives the rotation speed of the turbine 3, the output of the generator 4, the intake conditions (temperature, pressure), the exhaust gas temperature, etc., and inputs the valves 62, 66, 67, Valve 63 and gas compressor 61
Controls the operation of.

Hereinafter, the operation of the combustor 2 will be described together with the fuel supply control method according to the present invention. First, control at the time of starting will be described with reference to FIG. FIG. 4 is a time chart showing the control at the time of starting. Hereinafter, unless otherwise specified, the control is performed by the controller 5.

At time t ₀ , a starter motor (not shown) is driven to rotate the turbine 3 and the compressor 1 directly connected thereto.

When the rotation speed of the turbine 3 reaches a predetermined rotation speed (at time t ₁ ), the ignition device 26 is turned on, and thereafter, at time t ₂ , the gas shutoff valve 62 is opened. However, times t ₁ and t ₂ may be at the same time. At this time, the line L
2. The flow control valves 66 and 67 and the solenoid valve 63 on L3 are all set to the closed state. By opening the gas shut-off valve 62, the city gas compressed by the gas compressor 61 is sent to the pilot nozzle 23 after the flow rate is adjusted by the fixed orifice via the lines L1 and L10.
In this way, fuel is supplied to the pilot section, and the ignition device 2
6 ignites in the combustion chamber 22 to form a diffusion flame.

By driving the turbine 3 by guiding the high-temperature gas obtained in the combustion chamber 22 to the turbine 3 by the diffusion flame thus formed, the rotation speed of the turbine 3 increases. By detecting the increase in the number of revolutions, the success or failure of ignition of the pilot portion can be reliably determined. Also, when ignition is successful, the temperature of the exhaust gas,
Since the outlet pressure of the compressor 1 and the load of the generator 4 also increase,
The success or failure of ignition may be determined based on these changes.

When it is determined that the ignition has succeeded (at time t ₃ ), the flow control valve 66 on the line L 2 is opened, and the opening thereof is gradually increased, so that the fuel supplied to the primary fuel nozzle 24 is reduced. Increase the amount. Thus, the fuel supplied from the primary fuel nozzle 24 is supplied from the compressor 1 to the space 2.
It mixes with the combustion air introduced through 1 a and is introduced into the combustion chamber 22 through the primary premixing passage 27. Then, the flame is ignited and burned by the diffusion flame of the pilot portion formed inside, and a stable primary premixed flame is formed on the outer periphery and downstream of the diffusion flame. By increasing the fuel supply amount in this way, the rotation speed of the turbine 3 can be increased, and a smooth start-up can be performed.

In the present invention, by using the fixed orifice for adjusting the supply amount of the pilot fuel, the reproducibility of the supply amount is higher and the flow rate can be reliably set as compared with the case where the fuel supply amount is controlled by the control valve. As a result, reliable and stable ignition can be realized. To perform the same control with a control valve, an expensive control valve with an actuator is required.However, the fixed orifice has a simple configuration and can be realized at low cost, which has the advantage of reducing equipment costs and improving maintainability. .

Next, the fuel control method during the partial load operation will be described. First, the basic concept of fuel control will be described with reference to FIG. FIG. 5 is a graph schematically illustrating the relationship between the load factor and the fuel supply amount together with the fuel supply type.

First, when the load is low (for example, when the load is less than 50%), only the pilot fuel gas and the primary fuel gas are supplied to perform combustion. Even in this low load region, for example, 30%
In the above load region, combustion is performed by increasing the amount of pilot fuel gas. When the load is high, the secondary fuel gas is added to perform combustion in three stages.

Next, specific control will be described with reference to FIGS. FIG. 6 shows the flow rate of each fuel gas with respect to the generated power (load) rate, and FIG. 7 shows the equivalent ratio of each fuel gas with respect to the generated power (load) rate. Here, FIG.
FIG. 7A is a graph when the intake air temperature is 15 ° C.
(B) is a graph when the intake air temperature is 40 ° C.

When the intake air temperature is 15 ° C., as shown in FIGS. 6 and 7, the amount of power generated by the generator 4 is about 50%.
In the following low load range, combustion is performed by supplying only the pilot fuel gas and the primary fuel gas. In the present invention, the supply amount of the pilot fuel gas is maintained substantially constant regardless of the load by adjusting the gas supply amount of the pilot fuel gas using the fixed orifice. Therefore, the diffusion flame formed in the central portion on the upstream side can be maintained in a stable state at the full load. Further, the solenoid valve 63 on the pilot fuel gas supply line L11 is operated to use only the fixed orifice 64 on the line L10 for adjusting the fuel supply amount when the load is about 30% or less. By using the fixed orifice 65 on L11 together and switching the supply amount of the pilot fuel gas to two stages, as shown in FIG. 7A, the equivalence ratio in the pilot portion is maintained substantially constant even in a high load region. can do. Note that if the pilot equivalent ratio can be set to a desired range in the entire load region, it is possible to simplify to only one fixed orifice without providing two fixed orifices as shown in FIG. . Alternatively, a method may be adopted in which two different orifices are prepared and the flow rate is adjusted to a predetermined flow rate by switching each of them.

In this low load range, the total gas supply amount is adjusted to a value corresponding to the load by adjusting the opening of the flow rate control valve on the primary fuel gas supply line L2 according to the load (the amount of generated power). Adjust so that By forming the primary premixed flame on the outer periphery on the downstream side of the pilot diffusion flame, the primary premixed gas can stably burn in a wide equivalent ratio range.

In a high-load region where the load is about 50% or more, the secondary fuel gas is supplied by opening the flow control valve 67 on the secondary fuel gas supply line L3, and operation is performed by three systems. In this case, the opening of the flow control valve 67 for adjusting the supply amount of the primary fuel gas is adjusted according to the inlet air condition and the turbine speed or the load while adjusting the opening of the flow control valve 67 according to the load. , So that the equivalent ratio with respect to the load becomes substantially constant. As a result, the combustion flame temperature of the primary premixed flame can be kept constant, and the generation of thermal NOx can be suppressed.

The secondary premixed flame formed on the outer periphery on the downstream side of the primary premixed flame can be burned at a leaner equivalence ratio by the pilot diffusion flame and the primary premixed flame. Therefore, generation of thermal NOx is suppressed, and high combustion efficiency can be obtained. Further, since the combustion temperature of the primary premixed flame on the inner peripheral side is kept substantially constant, a stable flame can be formed.

As a result, in the premixed combustor for a gas turbine according to the present embodiment, low NOx operation with a NOx concentration of 10 ppm (O ₂ = 16%) over almost the entire operation range with a load of 20 to 100% and 99.5% It is possible to realize the high combustion efficiency operation described above.

The timing of switching between the two-system operation and the three-system operation according to the load and the stepwise switching of the gas supply amounts of the pilot fuel gas and the primary fuel gas may be provided with an offset between when the load increases and when the load decreases. preferable.

That is, when the load is increased, when the load becomes 32% or more, the supply amount of the pilot gas is increased in a stepwise manner, the supply amount of the primary fuel gas is reduced by that amount, and the load is further reduced. The supply of the secondary fuel gas is started at the point in time when it becomes 55% or more, and the supply amount of the primary fuel gas is reduced accordingly. On the other hand, when the load decreases, the load becomes 50
%, The supply of the secondary fuel gas is stopped, and the supply amount of the primary fuel gas is increased by that amount. Further, when the load is reduced to about 28% or less, control is performed such that the supply amount of the pilot gas is reduced stepwise and the supply amount of the primary fuel gas is increased accordingly.

By providing an offset in this manner, even if the load periodically increases and decreases near the set value for switching,
Since the switching operation is not performed frequently, unnecessary wear and damage of valves and the like that operate at the time of switching can be prevented.
System reliability is improved. Further, the state of the flame in the combustion chamber 22 does not change frequently, and a stable combustion state can be maintained.

When the intake air temperature rises to 40.degree.
As shown in (b), the operable generated power range is shifted to a lower side of the generated power than in the case of 15 ° C. shown in FIG. 7 (a). By performing the control of switching the fuel supply of each system as described above, the entire equivalence ratio can be maintained almost constant in the entire operation range, and a stable flame is formed to reduce the NO
x, it is possible to achieve low CO combustion.

[0042]

As described above, according to the premixed combustor of the present invention, in the premixed combustor which performs combustion by combining diffusion combustion and premixed combustion using three fuel supply systems, By disposing a diffusion flame, which becomes a pilot flame, a primary premixed flame downstream, and a secondary premixed flame further downstream, combustion at a leaner equivalence ratio than normal becomes possible, and NOx concentration Low level of 10ppm (O ₂ = 16%)
With NOx, it is possible to achieve a high combustion efficiency of 99.5% or more.

According to the fuel supply control method of the present invention, the combustion flame temperature of the primary premixed flame is kept constant by adjusting the fuel supply amount to the primary fuel nozzle according to the intake condition. The secondary premixed flame can be formed with a lower equivalent ratio, and low NOx and high combustion efficiency can be realized.

Further, by supplying fuel to the pilot combustion nozzle through the fixed orifice, the fuel supply amount at the time of ignition can be always maintained substantially constant, so that reliable ignition can be performed.

Then, by supplying the primary fuel after confirming the ignition of the pilot, reliable ignition and smooth acceleration can be realized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a premixed combustor for a gas turbine according to the present invention.

FIG. 2 is a view showing an end face of the combustor of FIG. 1;

FIG. 3 is a schematic configuration diagram illustrating a gas turbine power generation system using the premixed combustor of FIG. 1;

FIG. 4 is a time chart showing control at the time of starting the combustor of FIG. 1;

FIG. 5 is a diagram showing a relationship between a load factor and a fuel supply amount.

FIG. 6 is a diagram illustrating a relationship between a generated power amount and a fuel flow rate.

FIG. 7 is a diagram showing a generated power amount and an equivalent ratio of each gas.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Premix combustor, 3 ... Turbine, 4 ... Generator, 5 ... Controller, 6 ... Fuel supply system, 21 ... Outer cylinder, 22 ... Inner cylinder, 23 ... Pilot nozzle, 24 ... Primary fuel Nozzle, 25: secondary fuel nozzle, 26: ignition device,
27: primary premix passage, 28: secondary premix passage, 64
65: fixed orifice, 66, 67: flow control valve.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoichiro Okubo 41-41, Chuchu-Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central Research Laboratory Co., Ltd. 41, Yokomichi, Toyota Central Research Institute Co., Ltd. (72) Inventor Yoshinori Iwata, Yoshinori Iwata 41, Yoji, Chukuji, Nagakute-cho, Aichi-gun, Aichi Japan 1 Motomachi Toyota City Inside Motomachi Plant of Toyota Motor Corporation (72) Inventor Hiroshi Sato Inside Tokyo Gas Co., Ltd. 27F Shinjuku Park Tower 3-7-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo

Claims (5)

[Claims] 1. A pilot section having a pilot nozzle disposed in the center of a combustor, a primary premixed gas passage having a primary fuel nozzle disposed on an outer peripheral section thereof, and a secondary premixed gas passage having a primary fuel nozzle disposed on an outer peripheral section thereof. Via a secondary premixed gas passage having a fuel nozzle, and a fuel cutoff valve, the pilot nozzle, the primary fuel nozzle, and the secondary fuel nozzle are branched and connected to each other, and independently supply fuel to each nozzle. A premixed combustor for a gas turbine, comprising: a fuel supply system; and a combustion chamber inflow hole of the primary premixed gas passage downstream of an opening of the combustion chamber of the pilot section, and a fuel injection system further downstream of the pilot chamber. The inflow hole of the combustion chamber of the next premix gas passage is arranged, and a flow control valve is arranged in each of the branch passages of the fuel supply system to the primary fuel nozzle and the secondary fuel nozzle. Is and, in certain load or turbine speed above conditions, the pilot nozzle, the primary fuel nozzles,
While supplying fuel to all of the secondary fuel nozzles, adjusting the flow control valve that guides the fuel to the secondary fuel nozzles according to load fluctuations, and adjusting the flow rate to the primary fuel nozzles according to the intake conditions and the turbine speed or load. A premix combustor for a gas turbine, comprising a fuel control device for adjusting a flow control valve for guiding fuel. 2. The gas turbine according to claim 1, further comprising a switching means for stepwise switching a fuel supply amount to the fixed orifice and the pilot nozzle in a branch passage of the fuel supply system to the pilot nozzle. Premixed combustor. 3. The engine further comprises a determination means for determining an ignition state of the pilot section based on an increase in turbine speed, exhaust gas temperature, pressure, or load. The premixed combustor for a gas turbine according to claim 1, wherein in the case of a number, a flow control valve for guiding fuel to the primary fuel nozzle is adjusted according to a load change. 4. A fuel supply system supplies fuel through a fuel cutoff valve to a pilot nozzle, a primary fuel nozzle, and a secondary fuel nozzle of a premixed combustor for a gas turbine, which are branched and connected to the fuel nozzle. A fuel supply control method for a gas turbine premixed combustor, wherein the premixed combustor includes a pilot flame, a primary premixed flame, and a secondary premixed flame formed in a three-layer structure from an upstream side to a downstream side. In a premixed combustor, fuel is supplied to all of the pilot nozzle, the primary fuel nozzle, and the secondary fuel nozzle under the condition of a predetermined load or a turbine speed or more, and the fuel to the secondary fuel nozzle is supplied to the pilot nozzle. The supply amount is adjusted according to the load fluctuation, and the fuel supply amount to the primary fuel nozzle is adjusted according to the intake condition and the turbine speed or the load. Fuel supply control method of. 5. At startup, fuel is supplied only to the pilot nozzle, the flow rate is adjusted using a fixed orifice, and ignition of the pilot fuel is determined based on a rise in turbine speed, exhaust gas temperature, pressure or load. After the pilot fuel ignition was determined, fuel supply to the primary fuel nozzle was started and the amount of fuel supplied was increased to increase the turbine speed to the specified speed, and reached the specified turbine speed. In later load operation,
In an operation range equal to or less than a predetermined load, the fuel supply to the secondary fuel nozzle is shut off, the fuel supply amount to the primary fuel nozzle is adjusted according to the load variation, and a predetermined load within the operation range is reduced. 5. The fuel supply control method for a premixed combustor for a gas turbine according to claim 4, wherein the fuel supply amount to the pilot nozzle is increased when the pressure exceeds the limit.