JPH11343868A - Gas turbine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute operation corresponding to change with the lapse of time by estimating the flame temperature of a combustor, local air-fuel ratio, and a NOx quantity based on various operating conditions, and successively renewing the present operating conditions, in the control device for a gas turbine having the combustor consisting of diffusion and premixed burners. SOLUTION: Air is regulated in flow by guide vanes 5, and after being compressed into high pressure by a compressor 2, supplied to a combustor 3. Fuel is supplied to the combustor 3, after regulating the flow by diffusion and premixed fuel valve 6, 7. From the air and the fuel. combustion reacting high temperature gas is generated, and the gas is supplied to a gas turbine to be converted to power. In this case, in a control device 1, based on a fuel supply quantity, compressor discharge temperature, and gas turbine exhaust temperature respectively detected by respective detectors 10-13, the flame temperature of the combustor 3, local air-fuel ratio, and a NOx quantity are estimated, and in addition the estimated values are compared with the actual measured values detected with respective detectors 14, 15, to successively renew the present operating conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a heat source device such as a gas turbine using a low NOx combustor. In particular, it is necessary to adjust the fuel supply amount so as to achieve the set operation state in consideration of changes in the characteristics of each device due to aging, and to simultaneously reduce the amount of NOx generated during operation to an allowable value. Aim. Therefore, commercial power plants, cogeneration plants, private power plants, etc.
It is effective for operation monitoring equipment of a plant having heat source equipment and environmental protection equipment.

[0002]

2. Description of the Related Art In a conventional gas turbine operation adjustment, the gas turbine is operated according to a control set value based on an operation line set in advance by examining the performance of the combustor. Adjustment of control set value is being implemented.

[0003]

In the prior art, the control set value is not adjusted between the previous periodic inspection and the next periodic inspection, and the operation corresponding to the time-dependent characteristic change of the plant is not performed. Could not be implemented.

[0004]

In order to solve the above-mentioned problems, means for estimating a flame temperature, a local fuel-air ratio and an amount of generated NOx in a combustor, information from the means and a current operation state of the plant are provided. And means for adjusting the fuel valve opening so as to obtain an optimum fuel-air ratio by comparing the fuel cell and the fuel ratio of diffusion and premixing so that the NOx value becomes an allowable value.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where an embodiment of the present invention is applied to a gas turbine combined cycle power plant will be described below.

FIG. 1 shows an outline of the present invention.

[0007] The air volume is adjusted in accordance with the opening of the compressor inlet guide vanes 5, and becomes high pressure in the compressor 2.
Supplied to. The flow rate of the fuel is adjusted according to the degree of opening of the diffusion and premix fuel valves 6 and 7 and supplied to the combustor 3. Inside the combustor 3, high-pressure air from the compressor 2 and fuel from the fuel valves 6 and 7 generate combustion reaction high-temperature gas. The gas is supplied to the gas turbine 4 and converted into power.

The compressor inlet guide vane 5 is provided with a guide vane opening detector 8 for transmitting an opening signal to the control device 1. A fuel valve pressure gauge 9 is provided upstream of the fuel valves 6 and 7, and opening degree detectors 10 and 11 are provided for each valve, and each signal is transmitted to the control device 1. A compressor discharge temperature detector 12 is provided at the outlet of the compressor 2, and transmits a discharge air temperature signal to the control device 1. The exhaust temperature detector 13 and the NO
An x detector 14 and a rotation speed detector 15 are provided,
Each signal is transmitted to the control device 1.

Next, the contents of the control device 1 will be described. First, the fuel amount adjustment will be described with reference to FIG.
The fuel-air ratio is calculated by the following method. A signal from the compressor discharge air temperature detector 12 and a signal from the fuel-air ratio temporary setting generator 16 are input to a flame temperature calculator 17. The arithmetic unit 1
7 is set with a flame temperature calculation formula using the air temperature and the fuel-air ratio as arguments, and calculates the flame temperature calculation value into the exhaust temperature calculator 1.
8 is output. A calculation formula for adiabatic expansion is set in the arithmetic unit 18, and outputs the calculated exhaust gas temperature of the gas turbine 4 to a subtractor 19. The signal from the exhaust gas temperature detector 13 is input to the subtractor 19, and the difference between the two signals is output to the determiner 20. If the signal from the subtracter 19 is not within the allowable range, the fuel-air ratio initially updated by the fuel-air ratio updater 21 is updated, and then input to the flame temperature calculator 17 again, and the calculation is repeated until the signal reaches the allowable range. If the output of the subtractor 19 is within the allowable range, the output is determined to be the fuel-air ratio in the current plant operation state, and is output to the divider 23.

[0010] The fuel flow rate is calculated by the following method. The signal from the fuel valve pressure detector 9 and the signals from the diffusion and premixed fuel valve opening detectors 10 and 11 are combined with the fuel flow rate calculator 2
2 is input. The computing unit 22 is set with a flow rate calculation formula using the valve base pressure and the valve opening as arguments, and outputs the calculated fuel amount to the divider 23. The divider 23 divides the fuel amount and the fuel-air ratio to reduce the air amount by a subtractor 25.
Output to

The amount of air is calculated by the following method. Signals from the rotation speed detector 15 and the guide vane opening detector 8 are input to an air flow calculator 24. The computing unit 24 is set with a compressor air amount calculation formula having the rotation speed and the guide vane opening as arguments, and outputs the calculated air amount value to the subtractor 25. The output of the subtracter 25 is input to the determiner 26, and when the input value is 0, it is output as a signal 1 that holds the current operating state. When the signal of the subtractor 25 is other than 0,
Further, it is output to the decision unit 27. When the input value of the determiner 27 is positive, a signal 2 for increasing each fuel valve opening is output. When the input value of the judging device 27 is negative, a signal 3 for decreasing the opening of each fuel valve is output.

Next, adjustment of the premixed fuel ratio will be described with reference to FIG. The fuel amount information from the calculator 22 and the signal from the premixed fuel ratio provisional set value generator 30 in FIG. 2 are input to the multiplier 28 and output to the divider 29 as the premixed fuel amount. On the other hand, the signal from the tentative set value generator 30 is subtracted from 1.0 set in the constant generator 32 by a subtractor 31 and input to a multiplier 33 as a diffusion fuel ratio. Is multiplied by the fuel amount information from the controller and output to the divider 34 as a diffusion fuel amount. The air amount information from the divider 23 in FIG. 2 is input to the air distribution calculator 37. An empirical formula for air distribution for premixing and diffusion combustion obtained in advance by an element test or the like is set in the arithmetic unit 37, and outputs the amounts of premixing and diffusion air to the dividers 29 and 34, respectively. The premixed fuel-air ratio and the diffusion fuel-air ratio are calculated by the dividers 29 and 34, and the premixed combustion NOx
Generation amount calculator 35 and diffusion combustion NOx generation amount calculator 36
Output to The empirical formulas of the premixed and diffused combustion NOx generation amounts obtained in advance by element tests and the like are set in the arithmetic units 35 and 36.
The x generation amount is output to the adder 39.

The fuel / air ratio information from the determiner 20 and the local fuel / air ratio information from the dividers 29 and 34 in FIG. 2 are output to an interference combustion NOx generation amount calculator 38. The computing unit 38
Is set in advance, an empirical formula of the amount of NOx generated by interference combustion obtained by an element test or the like is set, and the amount of generated NOx generated by interference combustion is output to the adder 39. The adder 39
1 and the signal from the NOx detector 14 in FIG. 1 are subtracted by the subtractor 40, and the output is output to the determiner 41. When the output value is 0, it is output as a signal 4 for maintaining the current operation state. If the signal of the subtractor 40 is other than 0, it is further output to the decision unit 42. The determiner 42
Is positive, the signal 5 is output to increase the premixed fuel valve opening so as to increase the premixed fuel ratio and at the same time decrease the diffusion fuel valve opening. When the input value of the judgment unit 42 is negative, a signal 6 for decreasing the premixed fuel valve opening and simultaneously increasing the diffusion fuel valve opening so as to decrease the premixed fuel ratio is output.

[0014]

According to the above embodiment, the predicted values of the flame temperature, the local fuel-air ratio and the NOx amount in the combustor are compared with the measured values of the characteristics of the actual machine, and the optimum operating fuel is determined based on the obtained information. The current operating conditions can be sequentially updated so that the air ratio and the optimal premixed fuel ratio are obtained.

[Brief description of the drawings]

FIG. 1 is a system diagram of a gas turbine combined cycle power plant according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a fuel amount adjusting portion of the control device 1 of FIG. 1;

FIG. 3 is an explanatory diagram of a premixed fuel ratio adjustment portion of the control device 1 of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Control device, 2 ... Compressor, 3 ... Combustor, 4 ... Turbine, 5 ... Compressor inlet guide vane, 6 ... Diffusion fuel valve, 7 ... Premix fuel valve, 8 ... Guide vane opening detector, 9 ... Fuel valve pressure gauge, 10 ... Premixed fuel valve opening detector, 11 ... Diffusion fuel valve opening detector, 12 ... Compressor discharge air thermometer, 13 ... Exhaust temperature detector, 14 ... NOx detector, 15: rotation speed detector, 16: fuel / air ratio temporary set value generator, 17: flame temperature calculator, 18: exhaust temperature calculator, 19, 25, 31, 40 ...
Subtractor, 20, 26, 27, 41, 42...
... fuel-air ratio updater, 22 ... fuel flow rate calculator, 23, 29,
34: Divider, 24: Air flow rate calculator, 28, 33: Multiplier, 30: Premixed fuel ratio temporary set value generator, 32: Constant generator, 35: Premixed combustion NOx generation amount calculator, 36
... diffusion combustion NOx generation amount calculator, 37 ... air distribution calculation unit, 38 ... interference combustion NOx generation amount calculation unit, 39 ... adder.

Claims (3)

[Claims] 1. A control apparatus for a gas turbine having a combustor comprising a diffusion and a premix burner, wherein said combustion is performed on the basis of information on a fuel supply amount to each of said burners, a compressor discharge air temperature and a turbine exhaust temperature. Function to predict the flame temperature, local fuel-air ratio, and NOx amount in the heater, and to compare the output of this function with the measured values of each characteristic of the actual machine, and to sequentially update the current operating conditions based on the obtained information. And a control device for a gas turbine. 2. The fuel control apparatus according to claim 1, wherein the fuel flow rate calculation value obtained from the diffusion and premixing fuel flow rate control valve opening degree and the valve base pressure, and the fuel air ratio calculation value obtained from the flame temperature prediction value. Function to calculate the air flow rate from the calculated value and the air flow rate value obtained from the compressor rotation speed and the inlet guide vane opening degree information, and the optimal operating fuel-air ratio based on the information from this function A function of outputting an operation signal for each of the flow control valve opening degrees so as to adjust the flow rate of the fuel supplied into the combustor. 3. The control device according to claim 1, wherein the control unit controls the NO in the exhaust gas.
The x-concentration measurement value is compared with the calculated NOx amount obtained from the local fuel-air ratio prediction value, and the premixed fuel ratio is adjusted so as to be an allowable NOx value. A gas turbine control device having a function of outputting an operation signal of a valve opening degree.