JP3771677B2 - Pilot ratio automatic adjustment device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic adjustment device for a pilot ratio of a gas turbine combustor using both a diffusion nozzle and a premixing nozzle.
[0002]
[Prior art]
In conventional gas turbines, NO _x premix combustors to advance uniformly mixed combustion air and fuel in order to reduce (main nozzle: M) but has been adopted stable for narrow stable range of combustion combustion Difficult to sustain.
[0003]
Therefore it is used in combination with diffusion nozzles having excellent stability of ignitability and flame, but the diffusion nozzle (pilot nozzle: P) is flame temperature higher concentration of the NO _x is generated high. In other words, the flame is stabilized increasing the ratio of the pilot nozzle, the smaller the internal pressure variation of the combustor tends to NO _x is increased.
[0004]
Increasing the ratio of the main nozzle makes the flame unstable, and the internal pressure fluctuation increases due to factors such as the ratio of fuel to air, premixed combustion, and diffusion combustion, but NO _x decreases as the pilot ratio decreases. There is a tendency. These compromises are investigated to determine the ratio of pilot to main fuel (P / M ratio).
[0005]
FIG. 9 shows the combustor of the gas turbine described above, wherein (a) is a schematic longitudinal sectional view of the inside, and (b) is a front view. The combustor 30 includes eight main nozzles that form a premixed mixture of fuel and air, that is, four main nozzles 32-A and four main nozzles 32-B, and a central portion of the combustor 30. A pilot nozzle 31 called diffusion combustion is provided in order to stabilize the combustion of the fuel-lean premixed gas.
[0006]
Combustion of the pilot nozzle 31 is referred to as the diffusion combustion, have been used conventionally, while having excellent stability of the ignitability and the flame, the flame temperature is high, high concentration of the NO _x is generated.
[0007]
In the premixed lean combustion in which the air and the fuel are uniformly mixed and burned in advance, the generation of NO _x can be significantly suppressed by selecting an appropriate ratio of fuel and air (fuel / air ratio). On the other hand, it is difficult to maintain stable combustion.
[0008]
Figure 8 shows the trend of the pressure change and NO _x for the pilot ratio (P / M ratio), and proceeds to the right increasing the pilot ratio, the tendency of the pressure fluctuation decreases, NO _x increases. If the pilot ratio is lowered, it moves to the left and shows the opposite trend.
[0009]
Current control is to set the pilot ratio commensurate with the CSO (load) as shown in FIG. 7 in advance, the internal pressure variation, only load parameters determine the optimum value from the NO _x measured data.
[0010]
FIG. 6 is a system diagram of this control. A signal corresponding to the magnitude of the load from the load signal generator 21 is directly input to the pilot nozzle signal generator 22 and the main nozzle signal generators 23-1 and 23-2, respectively. The opening of the control valves 24, 25-A, 25-B connected to the nozzles is controlled by the output signals from the signal generators.
[0011]
In FIG. 6, the main nozzles are two series of A and B, but this controls the fuel from ignition to full load operation, so the controllability becomes worse with only one main A and pilot (fire type) ) And main A is ignited, and main B is thrown in during the load operation. For this reason, there are usually two main burners. Above this, the number of fuel pipes to the manifold and combustor nozzles increases, and control becomes complicated.
[0012]
[Problems to be solved by the invention]
In the operation after setting the P / M ratio of the conventional gas turbine described above, since control is performed only with the load parameter, the internal pressure fluctuation exceeds the allowable value due to aging deterioration, environmental change, etc. There is too much room for the allowable value, and the NO _x value also fluctuates.
[0013]
Therefore, when setting the P / M ratio, the present invention takes in the internal pressure fluctuation and NO _x value as parameters without depending only on the load, and optimally reduces the NO _x according to the constant fluctuation within the allowable internal pressure fluctuation value. It is an object of the present invention to provide a pilot ratio automatic adjustment device for a gas turbine that can correct the pilot ratio so that it can be operated.
[0014]
[Means for Solving the Problems]
The present invention provides the following means in order to solve the aforementioned problems.
[0015]
A combustor in combination with the main nozzle of the pilot nozzle and premix, and controlling the ratio of fuel between the pilot nozzle and the main nozzle according to the load signal, the pilot ratio of the gas turbine to perform optimum low NO _x reduction NO in the adjustment device, the pressure fluctuation detecting device for detecting the internal pressure variation of the combustor, the detected NO _x apparatus for detecting the amount of NO _x, the signal of the internal pressure variation value from the pressure fluctuation detecting device, from the detected NO _x apparatus enter the signal and the load signal of the _x value, as compared to the reference NO _x value and the reference internal pressure variation value with the load signal, the pilot nozzle ratio can be set low NO _x in the internal pressure variation allowable range in the load A pilot ratio automatic adjustment device comprising: an arithmetic device that outputs a correction signal.
Alternatively, a combustor in which a combination of the main nozzle of the pilot nozzle and premix, and controlling the ratio of fuel between the pilot nozzle and the main nozzle according to the load signal, the gas turbine for optimal low NO _x reduction in pilot ratio adjusting apparatus, a pressure fluctuation detecting device for detecting the internal pressure variation of the combustor, the detected NO _x apparatus for detecting the amount of NO _x, the signal of the internal pressure variation value from the pressure fluctuation detecting device, the detected NO _x apparatus The NO _x value signal and the load signal are input from the reference signal , compared with a reference NO _x value and a reference internal pressure fluctuation value determined from the load signal , and a correction signal for the NO _x amount and the internal pressure fluctuation is output. an arithmetic unit for outputting a correction signal to the pilot nozzle ratio can be set low NO _x within the allowable fluctuation range, the ratio of fuel of the pilot nozzle Wherein adding the correction signal adder and the pilot ratio automatic adjustment device characterized by comprising a.
[0016]
The present invention performs automatic adjustment control as a control parameter for this or the like by detecting the combustor pressure fluctuations and NO _x to the pilot nozzle / main nozzles ratio control in addition to the non-load signal for optimum low NO _x reduction control .
[0017]
The configuration of the present invention will be described with reference to FIG. 4, and the operation thereof will be described with reference to the flowchart shown in FIG. In FIG. 4, first, in (1), the ratio between the pilot nozzle and the main nozzle (P / M ratio) is set, and the detection signals from the internal pressure fluctuation detection device and the NO _x detection device are detected, and the calculation device (2) input. In the arithmetic unit (2), the correction signal (3) is obtained and added to the addition correction means (4). The addition correction means (4) controls the pilot nozzle control valve (6), and the main nozzle control valve (5) is controlled according to the P / M ratio set in (1). The configuration of the present invention is the portions (1), (2), (3) indicated by the two-dot chain line in the figure, and an external input device (7) is connected to the arithmetic unit (2) as necessary. Is done.
[0018]
5, first, in S1 pressure variation, P / M ratio commensurate with the load based on the measured database of the NO _x is set. Next, in S2, this is input to the calculator. Pressure variation to the load in S3, to detect NO _x, the correction signal of P / M ratio is calculated in the calculator, the correction signal is output. In S4, this correction signal is input to the adding means, and in S5, the bias value is added to the pilot ratio signal to perform bias correction. Next, in S6, the fuel control valve connected to the nozzle is controlled by the bias correction signal. On the other hand, in S7, the fuel control valve connected to the main nozzle is controlled on the main nozzle side by a main nozzle opening / closing signal corresponding to the load. The P / M ratio is automatically adjusted according to the degree of opening of both nozzles.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 is a system diagram of a pilot ratio automatic adjusting apparatus according to an embodiment of the present invention. In FIG. 1, the portion surrounded by a two-dot chain line is the same system as the conventional example of FIG. 6, and the characteristic portions of the present invention are portions indicated by reference numerals 1 to 5 in the drawing. These features are described in detail below.
[0020]
In FIG. 1, the conventional control portion will be described again. Signals from the load control signal generator 21 are directly input to the pilot nozzle signal generator 22 and the main nozzle signal generators 23-1 and 23-2, respectively. Only the so-called load parameters for controlling the control valves 24, 25-A, 25-B by the signals from the signal generators were controlled. Therefore combustor aging of, internal pressure fluctuations due to environmental changes or the like, could not follow to changes of the NO _x value.
[0021]
In the gas turbine using both the diffusion nozzle and the premixing nozzle, as described with reference to FIG. 8, when the pilot ratio is increased, the internal pressure fluctuation is reduced, but NO _x is increased. Further, when the pilot ratio is lowered, NO _x is lowered, but the internal pressure fluctuation is increased. Therefore, the upper limit of the pilot ratio in the NO _x, the lower limit will be limited by the internal pressure variation. Therefore, the P / M ratio is set according to the load as shown in FIG.
[0022]
When atmospheric environment change, material deterioration, combustor performance deterioration, fuel component change, etc. occur, the pilot ratio determined previously does not necessarily fall within the respective limit values of NO _x and internal pressure fluctuations and become the optimum point. In the embodiment of the present invention is therefore, to detect the internal pressure variation and NO _x, respectively, and the upper limit being limited by the NO _x to the load convectively by these signals, the proper pilot within the limit determined by the internal pressure variation A correction signal is output and adjusted so that the ratio becomes the same.
[0023]
Next, returning to FIG. 1, features in the embodiment of the present invention will be described. The combustor internal pressure fluctuation monitor 2 detects the internal pressure fluctuation, the NO _x monitor 3 detects the NO _x value, and both these signals are input to the arithmetic unit 1. In the arithmetic unit 1, a load control signal 21 is also input, and as shown in FIG. 2, the input load signal is equal to or lower than the upper limit of NO _x and the internal pressure fluctuation signal is equal to or higher than the lower limit of internal pressure fluctuation. A correction signal 4 for setting the pilot ratio in the range is output.
[0024]
This correction signal 4 is input to the adder 5 and is added to the pilot nozzle signal set by the pilot nozzle signal generator 22 to correct this, and the P / M ratio after the change is shown by hatching as shown in FIG. Adjust so that it is within the appropriate range shown in. Figure 2 is a load which is three elements that control is P / M ratio relationship diagram of a P / M ratio versus load, an upper limit determined by the three factors have to take the internal pressure variation and NO _x as a parameter, the control range lower limit As described above, the P / M ratio is automatically determined with respect to the change in the oblique line.
[0025]
Figure 3 is a flow chart showing the internal processing of the arithmetic unit 1, signals from the NO _x sensor enters the NO _X monitor 3, the current of the NO _x value is obtained. The signal from the internal pressure fluctuation sensor enters the internal pressure fluctuation monitor 2, and the current internal pressure fluctuation value is obtained. These NO _x values and internal pressure fluctuation values are compared with the reference NO _x values and reference internal pressure fluctuation values in the current load signal, and checked in S10 and S13. If the NO _X value is smaller than the reference NO _X value, a signal (correction value “0”) that maintains the state is generated in S11, and if NO _X is higher than the reference NO _X value, a pilot ratio decrease signal is generated in S12. .
[0026]
If the internal pressure fluctuation is smaller than the reference internal pressure fluctuation value, a signal (correction value “0”) that maintains the state is generated in S14, and if the internal pressure fluctuation is higher than the reference internal pressure fluctuation value, a pilot ratio increase signal is generated in S15. . These signals enter the adder 5 (as the correction signal 4) and are added to the signal of the pilot nozzle signal generator 22. This signal is the upper limit determined by the NO _X shown in FIG. 2, the opening adjustment of the pilot nozzle control valve 9 is carried out in a lower limit determined by the internal pressure variation in the limiter 6.
[0027]
As described above, in the embodiment described above, the internal pressure fluctuation monitor 2 and the NO _x monitor 3 detect the internal pressure fluctuation and NO _x , and the arithmetic device 1 outputs a signal for correcting the pilot nozzle generator signal to correct the pilot ratio. since the way, reliably than only control strategy parameters for conventional load, to allow the operation at the optimum low NO _x in the internal pressure variation tolerance, the pilot ratio is automatically adjusted.
[0028]
【The invention's effect】
The present invention, in a pilot ratio automatic adjustment device for a gas turbine, a pressure fluctuation detecting device for detecting the internal pressure variation of the combustor, the detected NO _x apparatus for detecting the amount of NO _x, the internal pressure variation values from the pressure fluctuation detecting device A signal, a signal of NO _x value and the load signal from the NO _x detection device are inputted, and compared with a reference NO _x value and a reference internal pressure fluctuation value in the load signal , NO is within an allowable range of internal pressure fluctuation at the load. and an arithmetic unit that outputs a correction signal so as to obtain a pilot nozzle ratio that can set _x low , and further includes an adder that adds the correction signal to the fuel ratio of the pilot nozzle . The following effects can be achieved.
[0029]
(1) Enables an optimal low NO _x operation within the permissible internal pressure fluctuation value.
(2) P / M ratio adjustment at the time of start-up after regular inspection is not required, and only the confirmation is made.
[Brief description of the drawings]
FIG. 1 is a control system diagram of an automatic pilot ratio adjusting device according to an embodiment of the present invention.
FIG. 2 is a diagram showing an adjustment range of a pilot ratio of the pilot ratio automatic adjustment device according to the embodiment of the present invention.
FIG. 3 is a flowchart inside the arithmetic unit of the pilot ratio automatic adjustment device according to the embodiment of the present invention.
FIG. 4 is a block diagram showing a configuration of the present invention.
FIG. 5 is a diagram illustrating the operation of the present invention.
FIG. 6 is a control system diagram of a conventional pilot ratio adjusting device.
FIG. 7 is a diagram showing a relationship between a conventional pilot ratio and a load.
FIG. 8 is a diagram showing the relationship between the pilot ratio, NO _x , and internal pressure fluctuation of a conventional gas turbine combustor.
9A and 9B show a combustor of a gas turbine, in which FIG. 9A is a schematic sectional view of the inside, and FIG. 9B is a front view.
[Explanation of symbols]
1 arithmetic unit 2 PT change monitor 3 NO _x monitor 4 correction signals 5 adder 21 load control signal generator 22 the pilot nozzle signal generator 23-1, 23-2 main nozzles signal generator 24,25-A, 25-B Control valve

Claims (2)

A combustor in combination with the main nozzle of the pilot nozzle and premix, and controlling the ratio of fuel between the pilot nozzle and the main nozzle according to the load signal, the pilot ratio of the gas turbine to perform optimum low NO _x reduction NO in the adjustment device, the pressure fluctuation detecting device for detecting the internal pressure variation of the combustor, the detected NO _x apparatus for detecting the amount of NO _x, the signal of the internal pressure variation value from the pressure fluctuation detecting device, from the detected NO _x apparatus _{An x} value signal and the load signal are input, and compared with a reference NO _x value and a reference internal pressure fluctuation value determined from the load signal , a correction signal for the NO _x amount and the internal pressure fluctuation is output , and the internal pressure fluctuation is allowed at the load. pilot ratio automatic adjustment, characterized in that an arithmetic unit for outputting a correction signal to the pilot nozzle ratio can be set low NO _x in the range Apparatus. It has a combustor that uses a pilot nozzle and a premixed main nozzle in combination, and controls the fuel ratio between the pilot nozzle and the main nozzle according to the load signal to achieve an optimal low NO _x In the pilot ratio adjusting device of the gas turbine that performs the conversion, the internal pressure fluctuation detecting device that detects the internal pressure fluctuation of the combustor, and NO _x NO to detect quantity _x A detection device, a signal of an internal pressure fluctuation value from the internal pressure fluctuation detection device, the NO _x NO from the detector _x Input the value signal and the load signal, and the reference NO determined from the load signal _x Compared with the value and reference internal pressure fluctuation value, NO _x Output a correction signal of the amount and the internal pressure fluctuation, and within the allowable range of the internal pressure fluctuation at the load, NO _x A pilot ratio automatic adjustment comprising: an arithmetic unit that outputs a correction signal so that a pilot nozzle ratio can be set low, and an adder that adds the correction signal to the fuel ratio of the pilot nozzle apparatus.

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