JPH09324657A - Gas turbine equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas turbine equipment which is favorable for contributing toward a stability of a system with a governor-free operation and securing a stable combustion under the time of fluctuated cycles of a system. SOLUTION: A combustion device 11 having a diffused combustion and a premixed combustion and a controller of a flow rate control valve 17 of diffused combustion fuel, and a flow rate control valve 16 of premixed combustion fuel is provided. Then, the flow rate of the fuel for diffused combustion is changed on the basis of a fuel control instruction (control signal) which is guided with a frequency change of the system and a request load which is set in advance. At the same time, the flow rate of the premixed combustion is changed independent of a fuel control instruction to remove and abrupt change of the premixed combustion fuel.

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 having premixed combustion and diffusion combustion, and more particularly to a gas turbine equipment for preventing misfire even if frequency fluctuations occur in the system.

[0002]

2. Description of the Related Art In recent gas turbine equipment, in order to reduce the NOx concentration discharged from the environment, there is a need to reduce the NOx concentration.
As described in Japanese Patent No. 215338, a low NOx combustor is used which is a combination of premixed combustion and diffusion combustion, and diffusion combustion generally controls gas turbine speed and load until premixed combustion is used. And the spark for premixed combustion,
Used for flame holding of premixed combustion flames. Regarding the control method of the combustor, JP-A-4-124522, JP-A-5-149544, and JP-A-4-124522.
As described in the publication, FIG.
As in 6, the injection amount of the premixed combustion fuel is determined based on the premixed combustion fuel command value.

[0003]

Governor-free control is one of the factors contributing to the load stability of gas turbine equipment in recent years. When power plants in the same grid operate at the same power arbitration rate, when the load increases or decreases in a short cycle,
The power generation output is instantaneously increased or decreased according to the fluctuation of the frequency of the grid. In this way, the power stations in the same grid are governor-free controlled to stabilize the frequency on the grid. However, the system frequency fluctuates due to various factors, and especially in the case of a system where nuclear power plants and coal-fired power plants occupy a high proportion, the output of the power plant cannot fully respond to load changes, so system stability is high. Is bad, and the amplitude of the system frequency is large. In the conventional gas turbine equipment described in JP-A-4-124522, when vibration of the system frequency occurs,
As shown in FIG. 17, the fuel control command (load required by the system) oscillates to perform the speed control, which causes the diffusion and premix combustion fuel command value to oscillate. Since the premixed combustion has a narrow flame-air ratio stable range of the flame, when the premixed combustion fuel command value oscillates, as shown in FIG. An IFC device (Internal Flow Cont) which is a device for adjusting the flow rate.
and an IGV device (Inlet Guide) that is a device for adjusting the intake air flow rate of the gas turbine compressor.
Vane) delays the timing of each operation, the fuel-air ratio of premixed combustion deviates from the proper range, and the flame becomes unstable due to vibration,
There is a problem that the flame of premixed combustion is lost. On the other hand, as shown in FIGS. 18 and 19, by limiting the fuel control command, high-frequency minute fluctuations in the fuel flow rate for premix combustion are removed, and misfire of the premix combustion flame is prevented. Compared to free operation, the contribution to system stability is lower.

An object of the present invention is to provide a gas turbine facility which contributes to system stability by governor-free operation of a gas turbine even when the system frequency fluctuates and which ensures stable combustion.

[0005]

The above object includes a combustor having diffusion combustion and premixed combustion, and a control device for controlling the flow rate control valve for diffusion combustion fuel and the flow rate control valve for premixed combustion fuel. , While varying the flow rate of the diffusion combustion fuel based on the fuel control command derived from the system frequency variation and the preset required load, and varying the flow rate of the premixed combustion fuel independently of the fuel control command, It is solved by eliminating sudden fluctuations. Further, a combustor having diffusion combustion and a plurality of premixed combustions, a control device for controlling the flow control valve for the diffusion combustion fuel and the flow control valve for the plurality of premixed combustion fuels supplied to the plurality of premixed combustions are provided. The flow rate of the diffusion combustion fuel is varied based on a fuel control command derived from the system frequency variation and a preset required load, and the flow rates of a plurality of premixed combustion fuels are independent of the fuel control command. It is solved by making it fluctuate and eliminating sudden fluctuations. Further, the problem is solved by including the IGV device and the IFC device, operating the IGV device and the IFC device independently of the fuel control command, and subordinating the flow control operation of the fuel for premixed combustion.

The present invention can form a signal excluding the high frequency minute fluctuation component of the fuel control command, whereby the flow rate of the fuel flow control valve for premixed combustion is fluctuated independently of the fuel control command, and the gas is controlled. Excludes sudden fluctuations in fuel flow rate due to the fuel flow control valve for premixed combustion during turbine / governor-free operation, and makes the operation of the IFC device and IGV device dependent on the operation of the fuel flow control valve for premixed combustion. By doing so, even when the system frequency fluctuates, the governor-free operation contributes to system stability, the premixed combustion fuel-air ratio can be maintained in the combustible range, and a stable premixed combustion flame can be formed. Further, by providing the combustor with a plurality of systems for supplying the fuel for premixed combustion, the equipment of the IFC device can be omitted, and the system can be simplified and inexpensively constructed.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of gas turbine equipment showing an embodiment of the present invention. 1, in the gas turbine equipment, a generator 5 is directly connected to a shaft of a gas turbine 3 composed of a compressor 1, a turbine 2, and a combustion device 7, and a tachometer 8 is provided between the gas turbine 3 and the generator 5. Is installed in. The gas turbine controller 9 provides information on the bus frequency from the generator 5, the gas turbine speed from the tachometer 8, and the exhaust gas temperature from the exhaust gas thermometer 10 inserted in the gas turbine exhaust gas 4. And based on this, for the purpose of being within the allowable temperature range of the gas turbine equipment, increasing the thermal efficiency of the gas turbine as high as possible, and decreasing the NOx concentration of the gas turbine exhaust gas 4 as low as possible, By controlling the IGV device 6 to adjust the compressor intake air flow rate and controlling the combustion device 7, the input fuel amount and the premixed combustion fuel-air ratio are adjusted to control the gas turbine speed and load.

FIG. 2 shows details of the combustion device 7 of FIG.
The combustor 11 includes a diffusion combustion nozzle 20, a premixing combustion nozzle 21, and an IFC device 12. The IFC device 12 operates by the IFC drive device 13 that receives the command signal from the gas turbine control device 9, and adjusts the premixed combustion fuel-air ratio. The diffusion combustion nozzle 20 and the premix combustion nozzle 21 are respectively connected to a diffusion combustion fuel pipe and a premix combustion fuel pipe branched from a fuel pipe connected to a fuel source (not shown). Fuel flow control valve for diffusion combustion 17 installed in the fuel pipe for diffusion combustion and fuel flow control valve 16 for premixed combustion installed in the fuel pipe for premix combustion
Receives a command signal from the gas turbine control device 9,
The fuel flow rate for diffusion combustion and the fuel flow rate for premixed combustion are adjusted respectively. The fuel pressure control valve 15 for diffusion combustion installed in the fuel pipe for diffusion combustion and the fuel pressure control valve 14 for premixed combustion installed in the fuel pipe for premixed combustion receive signals from the gas turbine control device 9. , The fuel pressures of the diffusion combustion fuel flow rate control valve 17 and the premixed combustion fuel flow rate control valve 16 are adjusted to adjust the diffusion combustion fuel pressure control valve 15 and the premixed combustion fuel pressure control valve, respectively. 14 controllability is enhanced. Since, for example, 14 same combustors 11 are installed for one gas turbine 3, a combustor 11 for diffusion combustion installed in the fuel pipe for diffusion combustion and a fuel pipe for premixed combustion are installed in the combustor 11. By the installed premixed fuel manifold 18, the fuel pipes are branched by the number of combustors and are connected to the combustors 11.

FIG. 3 shows the details of the circuit in the gas turbine controller 9 of FIG. The gas turbine controller controls the bus frequency from the generator 5 in FIG. 1, the gas turbine speed from the tachometer 8 and the exhaust gas temperature from the exhaust gas thermometer 10 inserted in the gas turbine exhaust gas. The information is fetched, and the fuel control command 23 is guided by the calculator 22 together with the required load. By branching this signal in two directions and passing the change rate limiter 24 in one direction, a sudden change in the fuel control command as indicated by the solid line rather than the broken line in FIG. 4 is eliminated. In FIG. 4, the broken line and the solid line respectively show the fuel control command values before and after passing through the change rate limiter 24 in the present embodiment, and the alternate long and short dash line shows the maximum increase / decrease amount in the stable premixed combustion range. . Further, the computing unit sampling time in the figure represents the time from the computing unit 28 outputting the fuel control command 23, to the fetching of the various gas turbine operation information again and the outputting of the combustion control command 23. Data as shown in the graph of FIG. 5, that is, the diffusion fuel ratio (diffusion fuel command value / combustion control command) with respect to the combustion control command value is input into the function generator 27, and the data passes through the change rate limiter 24. The signal is acquired and the diffusion fuel ratio is calculated. The premixed fuel command value is determined by multiplying the diffusion fuel ratio and the signal passed through the change rate limiter 24 by the multiplier 25, and further subtracting the signal from the signal passed through the change rate limiter 24 by the subtractor 26. To do. The premixed fuel command value in this case is a premixed fuel command without abrupt changes as shown in FIG. On the other hand, the difference between the signal that has not passed through the rate-of-change limiter 24 and the signal that has passed through the rate-of-change limiter 24 is calculated by the subtractor 28, and this is converted into the signal output from the multiplier 25 by the adder 29. By adding, the diffusion fuel command value is determined. The diffusion fuel command value in this case is a diffusion fuel command as shown in FIG. The IGV device and the IFC device are controlled by the signal passing through the rate-of-change limiter 24 at a variation rate depending on the premix fuel command value. Further, when the shaft protection signal 55 issued when the gas turbine has to be brought to an emergency stop, the fuel control command passes through the rate-of-change limiter 24 and the signal is not restricted. The premix fuel command can be set to 0, and the gas turbine is stopped at the same time as the conventional example.

As described above, according to the present embodiment, the fuel flow rate fluctuation during the gas turbine / governor-free operation is as shown in FIG. 6, and the rapid fluctuation which causes the misfire of the premixed combustion is eliminated, Further, by substituting the operation of the IFC device and the operation of the IGV device with the operation of the fuel flow rate control valve for premixed combustion, it is possible to eliminate the timing difference between the operation of the IGV device, the operation of the IFC device, and the premixed fuel command. Governor-free operation contributes to system stability even when the system frequency fluctuates, keeps the premixed combustion fuel-air ratio in the combustible range, prevents premixed combustion misfire, and forms a stable premixed combustion flame. it can.

FIG. 7 shows another embodiment of the present invention. The difference between this embodiment and the embodiment of FIG. 1 is that the IFC device 12 is not provided in this embodiment, and that the premixed combustion fuel flow rate control valve 16 and its control system are those of the embodiment of FIG.
Although it was a formula, there are four formulas in this embodiment. Hereinafter, description will be made with reference to the drawings. 7, the same reference numerals as those of the embodiment of FIG. 1 indicate the same or corresponding portions. The difference between FIG. 7 and FIG. 1 is not the combustion device 7,
The combustion device 30 is installed, and the gas turbine control device 40 is installed instead of the gas turbine control device 9.

FIG. 8 shows details of the combustion device 30 of FIG. 8 and FIG. 2 indicate the same or corresponding parts. The difference between FIG. 8 and FIG. 2 is that the IFC device 12 and the IFC drive device 13 are not installed, and the pipes are divided into four directions between the premixed combustion fuel pressure control valve 14 and the combustor 31. The first pipe in which the primary premixed fuel flow rate control valve 36 is installed is connected to the primary premixed combustion nozzle 32 to control the primary premixed fuel flow rate, and the secondary premixed fuel flow rate control valve 37 is installed. The second pipe is connected to the secondary premixed combustion nozzle 33 to control the secondary premixed fuel flow rate, and the third pipe in which the tertiary premixed fuel flow rate control valve 38 is installed is the tertiary premixed combustion nozzle. 34 to control the third-order premixed fuel flow rate, and to control the fourth-order premixed fuel flow rate control valve 39.
The fourth pipe where is installed is the quaternary premixed combustion nozzle 3
5 is connected to control the quaternary premixed fuel flow rate. In the combustion device 30, the premixed combustion fuel-air ratio is adjusted by controlling the primary, secondary, tertiary, and quaternary premixed fuel flow rates as shown in FIG. Further, since, for example, 14 combustors 31 are installed as in the first embodiment of FIG. 1,
Primary premix fuel manifold 51, secondary premix fuel manifold 52, and tertiary premix fuel manifold 53
Then, the fuel pipes are branched by the number of combustors by the fourth-order premixed fuel manifold 54 and connected to the combustors 31, respectively.

FIG. 10 shows the gas turbine controller 4 of FIG.
Details of the circuit within 0 are shown. The same symbols in FIG. 10 and FIG.
Identical or equivalent parts are shown. The gas turbine control device 40 includes a bus frequency from the generator 5 in FIG. 7, a gas turbine rotation speed from the tachometer 8, and an exhaust gas temperature from the exhaust gas thermometer 10 inserted in the gas turbine exhaust gas. Information is taken in as information, and the required load is also added to the computing unit 2
At 2, the fuel control command 23 is introduced. This signal is 2
By branching in one direction and passing one through the change rate limiter 24, the change rate is limited in the same manner as in FIG. 3, and based on this, the multiplier 41 and the fuel control command are spread as shown in the graph of FIG. The function generator 42 for calculating the fuel ratio determines the primary premixed fuel command value, and the multiplier 43 and the function generator 44 for calculating the diffusion fuel ratio from the fuel control command as shown in the graph of FIG. The third premix fuel command value is determined by the multiplier 45 and the function generator 46 that calculates the diffusion fuel ratio from the fuel control command as shown in the graph of FIG. 47 and a function generator 48 for calculating the diffusion fuel ratio from the fuel control command as shown in the graph of FIG. 14 determines the quaternary premixed fuel command value.
In addition, from the signal not passing through the rate-of-change limiter 24, the adder 4
9 and the subtracter 50 subtract the premixed fuel command value to determine the diffusion fuel command value. The IGV device is controlled by a signal that has passed through the rate-of-change limiter 24 at a rate of change depending on the premix fuel command value. Also, the shaft protection signal 55 issued when the gas turbine must be stopped in an emergency
Is input, the fuel control command is the change rate limiter 24.
Since there is no restriction on the signal, the premix fuel command can be set to 0 at the same time as the conventional example, and the gas turbine can be stopped at the same time as the conventional example.

As described above, according to the present embodiment, the fuel flow rate fluctuation during the gas turbine / governor-free operation is as shown in FIG. 15, and the rapid premixed fuel command that causes the misfire of the premixed combustion is generated. It is possible to eliminate fluctuations and eliminate the timing lag between the operation of the IGV device and the premix fuel command,
Since the misfire of the premixed combustion can be prevented and the IFC device does not have to be equipped, the system can be simplified and the cost can be reduced.

In the examples shown in FIGS. 9, 11, 12, 13, and 14, the premixed fuel command is the primary premixed fuel command value, the secondary premixed fuel command value, and the tertiary premixed fuel command. The value generator and the fourth-order premixed fuel command value are equally divided into one or two or three or four, but the function generators 42, 44,
By arbitrarily changing the input formulas of 46 and 48, the gas turbine can be operated while preventing misfire of premixed combustion in the same manner as in the above example even in a state where the gas is not equally divided. Further, the present embodiment can be applied not only to control of the primary, secondary, tertiary, and quaternary premixed fuel flow rates but also to control of a plurality of premixed fuel flow rates equal to or higher than the quaternary premixed fuel flow rate. Needless to say.

[0016]

As described above, according to the present invention,
During governor-free operation of the gas turbine, even if the frequency of the system fluctuates, abrupt fluctuations in the flow rate of the fuel for premixed combustion that would cause misfire of premixed combustion are eliminated.
By substituting the operation of the FC device and the operation of the IGV device with the operation of controlling the flow rate of the fuel for premixed combustion, it is possible to eliminate the timing difference between the operation of the IGV device, the operation of the IFC device, and the premixed fuel command. The free operation contributes to system stability, keeps the premixed combustion fuel-air ratio in the combustible range, prevents misfire of the premixed combustion, and can form a stable premixed combustion flame. Further, by providing a plurality of systems for supplying the fuel for premixed combustion to the combustor,
The equipment of the IFC device can be omitted, the system can be simplified, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a gas turbine facility showing an embodiment of the present invention.

FIG. 2 is a detailed view of a combustion device according to an embodiment of the present invention.

FIG. 3 is a detailed view of a gas turbine control device according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating fuel control commands before and after passing through a rate-of-change limiter according to an embodiment of the present invention.

FIG. 5 is a diagram showing a diffusion fuel ratio with respect to a fuel control command value in one embodiment of the present invention.

FIG. 6 is a diagram showing a fuel command value according to an embodiment of the present invention.

FIG. 7 shows another embodiment of the present invention.

FIG. 8 is a detailed view of a combustion device according to another embodiment of the present invention.

FIG. 9 is a fuel command value for a gas turbine load according to another embodiment of the present invention.

FIG. 10 is a detailed view of a gas turbine control device according to another embodiment of the present invention.

FIG. 11 is a diagram showing a ratio of a primary premixed fuel command value to a fuel control command value in another embodiment of the present invention.

FIG. 12 is a diagram showing a secondary premixed fuel command value ratio with respect to a fuel control command value in another embodiment of the present invention.

FIG. 13 is a diagram showing a tertiary premixed fuel command value ratio with respect to a fuel control command value in another embodiment of the present invention.

FIG. 14 is a diagram showing a fourth-order premixed fuel command value ratio with respect to a fuel control command value in another embodiment of the present invention.

FIG. 15 is a diagram showing a fuel flow rate according to another embodiment of the present invention.

FIG. 16 is a diagram illustrating a fuel command value with respect to a gas turbine load.

FIG. 17 is a diagram for explaining a conventional fuel control command and a diffusion / premixed combustion fuel command value.

FIG. 18 is a diagram for explaining the limitation of fuel control command, diffusion, and fuel flow rate for premix combustion.

FIG. 19 is a diagram for explaining fuel control command limits, diffusion, and fuel flow rate for premix combustion.

FIG. 20 is a diagram for explaining a timing shift due to a delay in response to a premix fuel command.

[Explanation of symbols]

1 Compressor 2 Turbine 3 Gas Turbine 5 Generator 6 IGV Device 7, 30 Combustion Device 8 Tachometer 9, 40 Gas Turbine Control Device 10 Exhaust Gas Thermometer 11, 31 Combustor 12 IFC Device 16, 36, 37, 38 , 39 Premixed combustion fuel flow rate control valve 17 Diffusion combustion fuel flow rate control valve 22 Calculator 23 Fuel control command 24 Change rate limiter 25, 41, 43, 45, 47 Multiplier 26, 28, 50 Subtractor 27, 42, 44, 46, 48 Function generator 29, 49 Adder

Claims (6)

[Claims] 1. A combustor having diffusion combustion and premixed combustion, a fuel flow control valve for diffusion combustion that supplies fuel to the diffusion combustion, and a fuel flow control for premixed combustion that supplies fuel to the premixed combustion. Valve, an IGV device for adjusting the intake air flow rate of the gas turbine compressor, the control valves, and the IG
A control device for controlling the V device and a means for detecting a frequency fluctuation of the system are provided, and the flow rate of the diffusion combustion fuel flow rate control valve is fluctuated based on the frequency fluctuation and a fuel control command derived by a preset required load. In addition, the gas turbine equipment is characterized in that the flow rate of the fuel flow control valve for premixed combustion is changed independently of the fuel control command to eliminate a sudden change. 2. The IFC device according to claim 1, wherein the IFC device adjusts an air flow rate for premixed combustion in order to maintain the premixed combustion fuel-air ratio in a combustible range, and the IFC device is provided independently of the fuel control command. A gas turbine facility characterized in that it is operated and is subordinate to the operation of a fuel flow control valve for premixed combustion. 3. A combustor having diffusive combustion and a plurality of premixed combustions, a fuel flow control valve for diffusive combustion for supplying fuel to the diffusive combustion, and a plurality of premixers for supplying fuel to the plurality of premixed combustions. A mixed combustion fuel flow rate control valve, an IGV device for adjusting the intake air flow rate of the gas turbine compressor, a control device for controlling the control valves and the IGV device, and means for detecting frequency fluctuations in the system, The fuel flow rate of the diffusion combustion fuel flow rate control valve is varied based on a fuel control command derived from the frequency variation and a preset required load, and the flow rates of the plurality of premixed combustion fuel flow rate control valves are controlled by the fuel control. A gas turbine facility characterized by changing independently of the command and eliminating sudden changes. 4. The gas turbine equipment according to claim 1 or 3, wherein the IGV device is operated independently of the fuel control command and is subordinate to the operation of a fuel flow control valve for premixed combustion. . 5. The control device according to claim 1, wherein the difference between the change rate limiter for limiting the change rate of the fuel control command and the fuel control command before and after the change rate limiter. , A function generator that generates a diffusion fuel ratio for the fuel control command, a multiplier that multiplies both outputs of the change rate limiter and the function generator, and a subtractor and a multiplier And a subtractor for subtracting the output of the multiplier from the output of the rate-of-change limiter to output a premixed fuel command value. Gas turbine equipment to do. 6. The control device according to claim 3, wherein the control device includes a change rate limiter that limits a change rate of the fuel control command, and a plurality of function generators that generate a diffusion fuel ratio with respect to the fuel control command. , Multiplying the outputs of the rate-of-change limiter and the outputs of the function generators to output a plurality of premixed fuel command values, and adding the outputs of the plurality of multipliers A gas turbine facility comprising: an adder and a subtractor that obtains a difference between the fuel control command and the output of the adder and outputs a diffusion fuel command value.