JP3278923B2 - Gas turbine power generator, control method for denitration device, and control device for denitration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a gas turbine power generator.
Device and control method of denitration device and control device of denitration device
You.

[0002]

2. Description of the Related Art Instead of diffusion combustion in which fuel and air are supplied from different injection ports and burned while being mixed in a combustion chamber,
Premixed combustion, in which fuel and air are premixed and then burned, is being used.

[0003] By using premixed combustion, the reaction region of combustion can be reduced, that is, the flame can be shortened, and high load combustion can be performed. Further, by using the fuel-lean premixed combustion method, it is possible to reduce NOx emissions. Such a lean premixed combustion method is being adopted in combustors of gas turbines and the like.

One problem of premixed combustion is that the flow velocity range in which a flame can be stably formed is narrow, and flashback and blowout are likely to occur. For this reason, in a combustor such as a gas turbine combustor in which the combustion amount greatly changes from startup to the maximum load, the mixing ratio of fuel and air is kept within a certain range where the NOx emission is low even when the load changes. Such an air flow control mechanism is required. For example, in the combustor described in U.S. Pat. No. 4,150,539, a method of controlling the air flow by moving a flame stabilizer in the axial direction of the combustor has been proposed.

[0005] By doing so, a stable premixed flame is always formed even when the load of the gas turbine changes, and NO
It is possible to reduce x emissions. However, the humidity and temperature of the atmosphere, the temperature of the combustion air, the properties of the fuel, and the calorific value also affect the stability of the premixed flame and the amount of NOx emission. For example, when the humidity in the atmosphere increases, the amount of NOx emission decreases, but flame stability decreases and misfiring easily occurs. To cope with such changes in atmospheric humidity,
Japanese Patent Application Laid-Open No. 2-33419 describes a method in which atmospheric humidity is detected, and the amount of air supplied to a premix combustion burner is changed based on the detection signal. However, it does not quantitatively describe how much the amount of air should be changed with respect to changes in atmospheric humidity, nor does it describe how to quantitatively determine the amount of change in air with respect to changes in atmospheric humidity. Since the atmospheric humidity varies considerably from region to region depending on the season, how to control the amount of air with respect to changes in the atmospheric humidity depends on each gas turbine device, seasonally, and region where it is installed. Decisions must be made based on driving results. Further, Japanese Patent Application Laid-Open No. 2-33419 does not describe a method for responding to a change in the amount of heat generated by the fuel, and therefore, when the atmospheric humidity and the amount of heat generated by the fuel change simultaneously, it is not possible to determine how much the air amount should be changed. .

[0006]

As described above, in the prior art, since the stability of the premixed flame and the NOx emission amount change due to the change in the atmospheric humidity, the air ratio of the premixed flame changes according to the change in the atmospheric humidity. Although it was recognized that it was necessary to change the air ratio, it was not quantitatively understood how much the air ratio should be changed. In addition, a method for quantitatively grasping the amount of change in the air ratio has not been proposed. Further, no consideration has been given to a control method when the atmospheric humidity and the fuel composition change simultaneously.

An object of the present invention is to provide a premixed combustion apparatus capable of minimizing a change in NOx emission due to an atmospheric temperature, a humidity, a change in fuel composition, and the like, always maintaining low NOx and maintaining good flame stability. It is to provide a combustion control method.

[0008]

SUMMARY OF THE INVENTION A gas turbine generator according to the present invention is provided.
The electric device ejects a mixed flow of fuel and air to form a flame
A combustor with a premixed combustion burner and a supply to the burner;
Air compressor and combustion gas discharged from the combustor.
A gas turbine connected to the air compressor driven by
Control the combustor according to the load fluctuation of the gas turbine
The central control room that sends the command and the gas turbine
Gas turbine power plant equipped with
The composition of the fuel flowing into the burner and the moisture concentration of the air
And the flame temperature obtained based on the air temperature and air ratio
If the calculated value is set in advance according to the gas turbine load,
And / or fuel supplied to the burner to fall within the range.
Has combustion control means for controlling the amount of air.
And Alternatively, the control method of the denitration apparatus
Connected to a combustion device having a request signal output means,
Denitration equipment that discharges exhaust gas from the equipment to the atmosphere
A control method, comprising:
Connect the ammonia flow control device to the basic control device
Air temperature, air humidity, air pressure, fuel composition, and combustion equipment
At least one of the amount of water supplied to the
Load request signal output means or ammonia flow control device
To correct the signal that controls the amount of ammonia injected
It is characterized by the following. Alternatively, the control device of the denitration apparatus of the present invention
The device is connected to a combustion device equipped with a load request signal output means.
Exhaust gas emitted from the combustion device to the atmosphere
A control device for a denitration apparatus, wherein the load request signal output means
The stage and the basic control device are connected, and the basic control device and the
Connect a near flow control device to control the air temperature, air humidity, air
Pressure, fuel composition, and amount of water supplied to the combustion device
At least one of the load request signal output means or
Means for inputting to the ammonia flow control device;
To control the amount of ammonia injection based on the input value
And means for correcting

As described above, in the prior art, if the atmospheric humidity, temperature, and fuel composition change simultaneously, it has been difficult to maintain an optimal combustion state with low NOx and good flame stability. This is because the combustion state of the flame is determined based on the mixture ratio of fuel and air.

On the other hand, the present invention seeks to determine the combustion state of the flame based on the flame temperature obtained by calculation. As the flame temperature, it is particularly desirable to determine the adiabatic flame temperature. The adiabatic flame temperature means the maximum temperature of the flame calculated. For adiabatic flame temperature, see LDSmoot and DTPratt, Pulverized-Coal
Combustion and Gasification, PLENUM PRESS, New York
(1979) and S. Gordonand B. McBride, Computer Program f
or Calculation of Complex ChemicalEquilibrium Comp
osition, NASA SP-273 (1971).

The present inventors have found that in premixed combustion with excess air, particularly preferably in premixed combustion with an air ratio of 1.0 or more and 2.2 or less, the composition of the fuel flowing into the burner, the moisture concentration of the air, and the air The flame temperature calculated from the temperature and the air ratio is used to calculate the NOx concentration and CO concentration discharged from the combustor,
Or, it has been found that it has a very good correlation with the limit of flame blowout, the limit of generation of vibration combustion, and the limit of flashback of flame.
The present invention has been found. The calculated adiabatic flame temperature shows the best correlation with these properties.

The findings of the present inventors will be described below.

[I] If the fuel composition and the flame temperature are the same, the NOx emission is almost the same even if the air ratio, the mixture temperature before combustion, and the moisture concentration in the mixture change.

[Ii] When the flame temperature is the same, the effect of the fuel composition on the NOx emission is as follows: the main component of the fuel and the calorific value of the fuel, or the main component of the fuel and the average number of carbon atoms in one molecule of the fuel, or If a physical quantity that can specify any of these quantities is known, it can be almost determined. In general, when the average number of carbon atoms in one fuel molecule increases, the NOx emission increases monotonously.

[Iii] If the jet velocity of the gas mixture is substantially the same, the flame temperature at which the flame blows out will change even if the fuel composition, the moisture concentration in the gas mixture, and the gas mixture temperature before combustion change. Almost the same.

[Iv] If the jet velocity of the gas mixture is substantially the same, the flame temperature at which oscillating combustion occurs even if the fuel composition, the water concentration in the gas mixture, and the gas mixture temperature before combustion change. Are almost the same.

[V] If the jet velocity or air flow rate of the gas mixture is substantially the same, the fuel composition, the water concentration in the gas mixture,
Even if the temperature of the air-fuel mixture before combustion changes, the flame temperature when the amount of emitted CO suddenly increases is almost the same.

From these facts, it is determined whether the combustion state is optimal even if the atmospheric humidity, temperature, and fuel composition change simultaneously.
It is possible to immediately determine what operation should be performed to keep the combustion state optimal. If it is possible to predict changes over time in the atmospheric humidity, temperature, and fuel composition, it is possible to know in advance the amount of fuel and the amount of air required to keep the combustion state optimal.

As a specific method of controlling the combustion state, for example, the following method is possible.

(A) For each load, the allowable range of the optimum flame temperature at which a flame with low NOx emission concentration and good stability is formed is input in advance to the control device, and the humidity and temperature of the combustion air are input. And the amount of fuel and / or the amount of air supplied to the burner is controlled such that the change in the temperature of the flame falls within an allowable range when the fuel composition changes.

(B) The relationship between the NOx emission concentration and the flame temperature, the relationship between the change rate of the NOx concentration emitted from the flame and the fuel calorific value or the average number of carbon atoms in one fuel molecule when the flame temperature is constant, and When the flame blows out, when vibration occurs, and when CO is generated, the relationship between the flame temperature and the ejection speed of the gas mixture of fuel and air or the flow rate of the gas mixture is made into a function and input to the control device in advance. By referring to these functions, the NOx emission concentration is low and the flame blows out,
The amount of fuel and / or the amount of air supplied to the burner is determined according to the load so that vibration or generation of CO does not occur.

[0022]

The object of the present invention is to judge and control the combustion state of a flame based on the calculated value of the flame temperature. The aim of the flame combustion control is to reduce the NOx emission concentration or CO emission concentration, to prevent the flame from blowing out, to prevent vibration or flashback. According to the present invention, the flame temperature is obtained by calculation based on the composition of the fuel flowing into the premixed combustion burner, the moisture concentration of the air, the temperature of the air, and the air ratio, and the combustion state is controlled based on the flame temperature. Even if the atmospheric humidity, temperature, and fuel composition change, the NOx emission concentration and CO emission concentration can always be reduced, and the combustion state can be controlled so that the flame does not blow out, vibrate, or flash back.

In determining the relationship between the combustion state and the calculated value of the flame temperature, it is desirable to further consider the composition of the fuel, the calorific value, and the like.

The flame to be controlled is a premixed flame in which fuel and air are mixed in advance and then burned. The fuel to be used may be either a gas or a liquid.
NG, LPG, city gas and the like can be used, and methanol, naphtha, ethanol, kerosene, light oil and the like can be used as the liquid fuel. In any case, it is desirable to use a fuel containing almost no nitrogen in the molecule. Maximum nitrogen content is 1%
It is desirable not to exceed.

According to the present invention, when the flame temperature is constant, the relationship between the change rate of the NOx concentration discharged from the flame and the calorific value of the fuel or the average number of carbon atoms in one molecule of the fuel is used for the denitration apparatus. The amount of supplied ammonia can also be controlled.

In the gas turbine power generator of the present invention, an air compressor, a combustor for burning fuel and high-pressure air supplied from the air compressor, and a fuel and air provided in the combustor are mixed in advance. A post-combustion burner of a premix combustion type, a gas turbine connected to the air compressor driven by combustion gas discharged from the combustor, and a control command to the combustor according to a load change of the turbine. And a generator connected to the turbine and a control device for controlling the fuel supply amount or air supply amount of the burner based on the adiabatic flame temperature.

In order to control the fuel supply amount or air supply amount of the burner based on the adiabatic flame temperature, it is assumed that the temperature, humidity, and fuel heat value of the combustion air flowing into the burner are certain representative values. The control unit of the central operating room is provided with a program in which the load of the turbine and the amount of air supplied to the premixed combustion burner, and the load of the turbine and the optimum combustion temperature in the premixed combustion burner at this time are associated with each other. Good.

Alternatively, assuming that the temperature, humidity, and fuel calorific value of the combustion air are assumed to be representative values, the load of the turbine and the amount of air supplied to the premix combustion burner, and the load of the turbine and the premix It has a program that relates the amount of fuel supplied to the combustion burner, and a program that relates the amount of air supplied to the premix combustion burner and the flame temperature at which the flame blows out at that time. At least one of a program relating the NOx emission concentration at this time and a program relating the fuel composition to be burned by the premixed combustion burner and the NOx emission concentration when the flame temperature is constant are transmitted to the control unit of the central operation room. It may be provided.

Further, assuming that the temperature, humidity, and fuel calorific value of the combustion air are representative values, the required load of the turbine and the amount of air supplied to the premixed combustion burner, and the required load of the turbine and Relationship between the program relating the amount of fuel supplied to the mixed combustion burner, the required load of the turbine and the range of the combustor outlet temperature at which the NOx emission concentration at this time is below the limit value and the misfire of the premixed combustion burner does not occur The attached program may be provided in the control unit of the central operation room.

As a control method of the gas turbine power generator, the actual gas concentration and temperature of the air supplied during the operation of the gas turbine and the gas temperature at the gas turbine inlet under the fuel calorific value are supplied. It is effective to compare the gas temperature at the gas turbine inlet with the gas concentration at the gas turbine when it is assumed that the moisture concentration in the air, the temperature and the fuel calorific value are certain representative values, and to control the fuel supply amount so that the temperature difference between them becomes small. It is.

Alternatively, the adiabatic flame temperature formed by the premixed combustion burner based on the actual moisture concentration, temperature, and fuel calorific value in the air supplied during operation of the gas turbine, and the adiabatic flame temperature in the supplied air. The moisture concentration, the temperature and the fuel calorific value are supplied to the premixed combustion burner by comparing the temperature with the adiabatic flame formed by the premixed combustion burner assuming a certain representative value so that the temperature difference between the two becomes small. A control method for changing the amount of fuel and / or the amount of air to be performed is effective.

By diagnosing the combustion state and displaying the result of the control on the display of the central operation room, an appropriate instruction can be given to the operator.

When one gas turbine is provided with a plurality of combustors, means for individually detecting the amount of air flowing into each combustor or means for individually detecting the combustion temperature in each combustor Is provided, the variation of the combustion temperature for each combustor can be corrected.

When the combustion control method of the present invention is used for a combustor provided with a flow path resistor against which a mixed gas jet of fuel and air collides as means for forming a premixed flame with a premixed burner, Since the temperature change of the premixed flame that heats the resistor is small, the flow path resistor is not rapidly heated,
Long life.

In the operating method of the gas turbine power generation equipment according to the present invention, if the adiabatic flame temperature of the premixed flame formed in the combustor is set to 1650K or more and 1970K or less, the premixed flame is not misfired. In addition, the amount of NOx emission can be reduced to a level at which a denitration device becomes unnecessary.

The present invention is also applicable to a combustor provided with a premix combustion burner and a diffusion combustion burner.

An invention for controlling the supply amount of fuel gas or combustion air based on the predicted value of the flame temperature has been made in a hot blast stove, and is described in JP-A-63-65230. However, the present invention does not consider the humidity of air at all.

[0038]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a system diagram of a gas turbine power generator according to an embodiment of the present invention.

The fuel is supplied from the fuel tank 39, vaporized by the vaporizer 72, and sent to the fuel supply pipe 71. After the flow rate of the fuel is controlled by the fuel flow rate control device 64, the fuel is sent to the gas turbine combustor 21. The fuel calorific value is measured by the fuel calorific value measuring device 1, and the fuel flow rate is measured by the fuel flow measuring device 2, respectively. Here, when the fuel to be used is a fuel having a low boiling point such as LNG, a part of the fuel is vaporized in the fuel tank, and the pressure in the fuel tank increases. At this time, in order to prevent the fuel tank from being destroyed, the pressure in the tank is measured by the fuel tank pressure measuring device 43, and when the pressure in the tank exceeds the limit value, the fuel tank pressure adjusting valve 12 is opened, and the gas in the tank is opened. Is discharged to the fuel supply pipe 71. Since the gas vaporized in the tank has many components having a low boiling point and is different from the composition of the fuel normally supplied, when the pressure regulating valve 12 in the fuel tank is opened, the fuel composition and the calorific value fluctuate.

When the fuel used is a water-soluble fuel such as methanol, the water content in the fuel affects flame stability and NOx emission concentration. In this case, a device 19 for measuring the water content in the fuel is required. When methanol, light oil, or the like is used as a fuel, the tank pressure measuring device 43, the tank pressure regulating valve 12, and the vaporizer 72 are not necessarily required.

The flow rate of the air 32 is measured by the air flow rate measuring device 7.
After the temperature and humidity are measured by the atmospheric temperature and humidity measuring device 8, the air is sucked into the air compressor 24 and becomes high-pressure air 33. The high-pressure air 33 is sent to the gas turbine combustor 21 after the pressure is measured by the air pressure measurement device 5 and the temperature is measured by the gas temperature measurement device 6 at the gas turbine combustor inlet. Here, when the amount of air sucked into the air compressor 24 can be calculated from the atmospheric temperature and humidity and the characteristics of the air compressor 24,
When the control device 65 is provided so that the amount of air sucked into the air compressor 24 is constant, the air flow measuring device 7 is not necessarily required.

The gas turbine combustor has an outer cylinder 22 and an inner cylinder 23.
Between the outer cylinder 22 and the inner cylinder 23.
3 flows as premixed combustion burners 59 as combustion air 58.
Supplied to Part of the high-pressure air 33 is air 5 for cooling the inner cylinder.
6 is supplied to the combustion chamber 61. A dilution air amount control device 42 is provided downstream of the combustion chamber 61. When the load on the gas turbine is small, a part of the combustion air 58 is discharged as diluted air 57 to the downstream side of the combustor. The fuel is supplied from the fuel nozzle 40, mixed with the combustion air 58, and burned by the premixed combustion burner 59. Due to the action of the flame stabilizer 60 provided in the premixed combustion burner 59, the flame stabilizer 6
A circulating stream of hot gas is formed downstream of zero and heat from this circulating stream stabilizes the premixed flame. The gas generated from the premixed flame is cooled by the inner cylinder cooling air 56 and the diluted air 57.
, And becomes a high-temperature combustion gas, and is led to the gas turbine 25 via the transition piece. Gas turbine 2
5 and the air compressor 2 connected to the gas turbine 25
4 and the high-temperature combustion gas 34 that has driven the generator 26 becomes a low-temperature combustion exhaust gas 35 and is guided to the flue gas denitration device 28. Nitrogen oxides in the low temperature flue gas 35 react with ammonia in the flue gas denitration device 28 and are converted to nitrogen. Ammonia is supplied from the ammonia tank 29, the flow rate is controlled by the ammonia flow rate control device 70, and the flow rate is measured by the ammonia flow rate measurement device 15.
8.

The low temperature flue gas 35 is also led to the waste heat recovery boiler 30. The steam turbine 27 is driven by the steam 36 generated in the waste heat recovery boiler 30. This steam turbine 27 is also connected to the generator 26. The steam 36 that drives the steam turbine 27 is converted into water 3 by the condenser 31.
7 and is supplied to the waste heat recovery boiler 30 again. Here, the positions of the waste heat recovery boiler 30 and the flue gas denitration device 28 may be reversed. The combustion exhaust gas 35 is supplied to the waste heat recovery boiler 30.
After that, the gas is mixed with the exhaust gas 69 from another gas turbine in the chimney 38 and released into the atmosphere.

In the gas turbine of FIG. 1, the fuel supply amount according to the load, the distribution ratio of the fuel supply amount supplied to each burner, the distribution of the fuel air 58 and the dilution air 57, and the flue gas denitration device 2
8 needs to be controlled. These flow rates and flow distribution are determined in accordance with a load request signal in a central operation room (not shown), and a fuel flow control signal, a fuel flow distribution control signal, an air flow distribution control signal, and an ammonia flow control signal are sent to the respective flow control devices. Is controlled.

FIG. 2 is a diagram showing a combustion control method in the gas turbine combustor 21 and a control method of the flue gas denitration device 28 when the gas turbine power generation equipment of FIG. 1 is used. The basic control device determines the fuel flow supplied to the combustor, the fuel flow distribution to each burner, and the air flow distribution of the air supplied to each burner and the dilution air based on the load demand. The basic control device determines the fuel flow rate, distribution, and air flow rate distribution based on a basic control plan input in advance. In the basic control plan, when the air temperature, humidity, pressure, flow rate, fuel composition, water content in fuel, and the like are set to planned values, the air flow distribution of air supplied to each burner and dilution air to the gas turbine load, The fuel flow supplied to the combustor and the fuel flow distribution to each burner are input. When the air temperature, humidity, pressure, flow rate, fuel composition, and water content in the fuel are all the same as the planned values, the fuel flow rate, distribution, and air flow rate distribution can be determined according to the basic control plan. NO
x It is necessary to correct the fuel flow, distribution, and air flow distribution so that the emission concentration does not fall below the limit value and the flame does not misfire. The control device according to the present invention has a function 1, which functions as a function of the relationship between the flame temperature and the NOx emission concentration, a function, which functions as a relationship between the fuel composition and the change in the NOx emission concentration 2, the flame temperature at which the flame blows out and the gas mixture. A function 3, which is a function of the relationship between the ejection speeds of the fuel cells, is input in advance, and the fuel flow rate, distribution, and air flow rate distribution are corrected based on these functions 1, 2, and 3. The corrected fuel flow, distribution, and air flow distribution are output to each control device. It is also output to the ammonia flow control device. The basic control device is controlled so that the flame temperature is kept substantially constant even when the air temperature, humidity, fuel composition, and water content in the fuel change so that a stable flame is formed with a low NOx emission concentration. You. However, even when the flame temperature is constant, the NOx emission concentration changes depending on the fuel composition, and therefore, it is necessary to control the flow rate of ammonia according to the change in the fuel composition. In the ammonia flow control device, the flame temperature output from the basic control device, the fuel composition when the flame temperature is constant, and the NOx
The ammonia supply amount is determined based on a function 2 that functions as a function of the change in the emission concentration.

FIG. 3 shows the basic control unit for controlling the fuel flow rate, distribution,
FIG. 4 is a diagram illustrating a method for determining an air flow distribution. First, the fuel flow, distribution, and air flow distribution of the basic control plan are output based on the load request. Next, the flame temperature of each burner is calculated based on the measurement results of the air temperature, humidity, pressure, flow rate, fuel composition, water content in fuel, and the fuel flow rate, distribution, and air flow rate distribution in the basic control plan. Next, referring to the functions 1, 2, and 3, when the fuel flow rate, distribution, and air flow rate distribution are set as the basic control plan values, it is determined whether the flame blowout does not occur or the NOx emission concentration does not exceed the limit value. . When it is determined that the flame blows out or the NOx emission concentration exceeds the limit value, the fuel flow rate, distribution, and air flow rate distribution are corrected. Next, the flame temperature is calculated based on the corrected fuel flow rate, distribution, air flow rate distribution and measurement results of the air temperature, humidity, pressure, flow rate, fuel composition, and water content in the fuel.
Refer to 2 and 3 to see if flame blowout occurs or NOx
It is determined whether the emission concentration does not exceed the limit value. Such operations are repeated, and after it is determined that the flame does not blow out and the NOx emission concentration does not exceed the limit value, the determined fuel flow rate, distribution, and air flow rate distribution are output. The fuel flow rate
Correction of distribution and air flow distribution may be performed for only one of them, or may be performed for all of them.

4 to 7 show examples of functions 1, 2, and 3. Here, it is shown in the form of a graph, but may be input in the control device in the form of a mathematical expression or a numerical value.

FIG. 4 is an example of the function 1, and shows the relationship between the adiabatic flame temperature and the NOx emission concentration at each burner. In function 1, the allowable upper limit of the NOx emission concentration in each burner is input in advance. Also, a certain representative property is specified for the fuel composition. Here, the heat value is designated as the representative property.

FIG. 5 is an example of the function 2, and is a diagram showing the relationship between the calorific value of fuel and the NOx emission concentration when the flame temperature is constant. Here, the ratio of the calorific value of the representative property value to the actual calorific value is plotted on the horizontal axis, and the NOx emission concentration ratio is plotted on the vertical axis.

Air temperature, humidity, pressure, flow rate, fuel composition,
The adiabatic flame temperature at each burner can be calculated from the measurement result of the water content in the fuel and the fuel flow rate, distribution, and air flow rate distribution. From the calculation result of the adiabatic flame temperature, based on FIG.
It can be determined whether the emission concentration is below the allowable limit. When the fuel calorific value is different from the representative property value, the NOx emission concentration obtained from FIG. 4 is corrected using FIG.

FIGS. 6 and 7 are examples of the function 3. FIG. FIG. 6 is a diagram showing the relationship between the ejection speed at each burner and the adiabatic flame temperature at which blowout occurs. Air temperature, humidity, pressure,
The adiabatic flame temperature and jet velocity at each burner can be obtained from the flow rate, fuel composition, the measurement result of the water content in the fuel, and the fuel flow rate, distribution, and air flow rate distribution. Can be determined. The horizontal axis in FIG. 6 may use the dilution air amount ratio, the amount of air supplied to each burner, the opening degree of the air flow control device, or the like instead of the ejection speed.
FIG. 7 is an example showing the relationship between the dilution air amount ratio and the adiabatic flame temperature at which blowout occurs at each burner.

FIG. 8 shows the basic control unit for controlling the fuel flow rate, distribution,
FIG. 9 is a diagram illustrating another example of a method for determining an air flow distribution.
Here, the functions 1, 2, and 3 are not used, and instead, the optimum adiabatic flame temperature at each burner and the allowable range of the adiabatic flame temperature at each load of the gas turbine are input in advance in the basic control plan. If the adiabatic flame temperature is within the allowable range, the flame does not blow out and the NOx emission concentration is low.

In this method, first, the fuel flow rate, distribution, and air flow rate distribution are output from the basic control plan according to the load request. Further, the allowable flame temperature and the allowable range of the adiabatic flame temperature are output. Next, the adiabatic flame temperature of each burner is calculated based on the measurement results of the air temperature, humidity, pressure, flow rate, fuel composition, water content in the fuel and the fuel flow rate, distribution, and air flow distribution, and the allowable adiabatic flame temperature is calculated. Compare with range. As a result of the comparison, when it is determined that the calculation result of the adiabatic flame temperature is outside the allowable range, the fuel flow rate, distribution, and air flow rate distribution are corrected, and the adiabatic flame temperature is calculated based on the correction result.
This operation is repeated so that the calculation result of the adiabatic flame temperature falls within the allowable range, and the fuel flow distribution and the air flow distribution are output.

When a diffusion combustion burner and a premix combustion burner are provided in the combustor 21, it is desirable to perform the control as shown in FIG. That is, according to the load request, the air flow distribution and the fuel flow distribution are output from the basic control plan. Also, the optimum gas turbine outlet temperature and the allowable range of the gas turbine outlet temperature at this time are output. The arithmetic unit calculates the air temperature, humidity, pressure, flow rate, fuel composition, and water content in the fuel based on the measurement results.
The fuel flow rate is determined and output so that the gas turbine outlet temperature matches the optimum temperature output from the basic control plan or falls within an allowable range. This method uses air flow distribution,
Since the fuel flow distribution is not changed, the flame temperature of each burner similarly changes by adjusting the fuel flow. Therefore, if the fuel flow rate is determined so that the gas turbine outlet temperature becomes the optimum value, the flame temperature of each burner also becomes the optimum value. This control method has a feature that the combustion state can be controlled so as to keep the flame temperature of each burner at an almost optimum state even if the amount of air supplied to each burner is not accurately known.

It is desirable that the allowable range of the adiabatic flame temperature, the calculated value, and the like be output to a display in the central control room.
FIG. 10 is an example of a result output to the display,
This is an example when the gas turbine power generator shown in Embodiment 1 is used. The relationship between the opening degree of the air flow control valve, the flame temperature when the flame blows out at that time, the flame temperature when the NOx emission exceeds a reference value, and the flame temperature under the optimum operation condition is shown. Also, the current operation state is shown. In this case, the current operating condition is that the flame temperature is slightly lower than the optimum value, and in order to obtain the optimum operating condition, the fuel supply amount is increased to increase the flame temperature, or the opening degree of the air flow control valve is increased. It turns out that it is necessary to increase.

In addition, it is also desirable to display the relationship between the required load and the optimum gas turbine outlet temperature. Of course, it is not limited to these.

[Embodiment 2] FIG. 11 shows a method of using the gas turbine power generator of Embodiment 1 to predict changes over time in air humidity, fuel calorific value, and gas turbine load, and control the combustion state based on the prediction results. This is an example. First, the changes over time in the air humidity, fuel heat value, and gas turbine load up to the present are measured and input to the temperature, heat value, and load change prediction device. The temperature, calorific value and load change predicting device are based on measurement results, past operation data, and factors affecting the temperature, calorific value, and load change, such as fuel tank pressure and weather forecast, based on the future air humidity. , Fuel calorific value and gas turbine load over time are predicted. The prediction result is input to the basic control device, and the basic control device refers to the functions 1, 2, and 3 and the basic control plan based on the input result, and predicts the air flow distribution, the fuel flow distribution, and the fuel supply amount. Is output.

By predicting the operating state in advance in this way, it is possible to quickly follow a sudden change in the amount of heat generated by the fuel.

By using the gas turbine power generator of the present invention, it is possible to minimize the change in NOx emission due to seasonal changes, fuel composition changes, installation areas, etc., to always maintain low NOx and to maintain good flame stability. Becomes possible. As a result, the amount of ammonia used in the denitration device installed in the gas turbine power generation equipment can be reduced. However, if the combustion state is controlled accurately using the gas turbine power generation device of the present invention, the denitration device can be eliminated. . Generally, in order to eliminate the need for a denitration device, the NO exhausted from the gas turbine combustor is required.
It is said that the x concentration needs to be 10 ppm or less in terms of 16% O ₂ .

FIG. 12 is a diagram showing an example of the relationship between the adiabatic flame temperature and the NOx concentration, and FIG. 13 is a diagram showing the relationship between the adiabatic flame temperature and the ejection speed. All are the results measured under atmospheric pressure. It is generally said that the NOx concentration increases in proportion to the 0.5 power of the pressure, and the combustion pressure in the gas turbine power generator is generally about 10 to 16 atm. In order to reduce the NOx concentration to 10 ppm or less when the combustion pressure is 10 atm, the NOx concentration at atmospheric pressure should be approximately 3.2 ppm or less, and to reduce the NOx concentration at 16 atm to 10 ppm or less. The NOx concentration at about 2.5 ppm or less. Based on the results of FIG.
Considering the condition that the NOx concentration is 10 ppm or less under 16 atm, the adiabatic flame temperature needs to be approximately 1890 to 1970K or less, depending on the combustor. On the other hand, when the adiabatic flame temperature becomes 1650-1720K or lower, the flame blows out regardless of the ejection speed. Therefore,
It is considered that maintaining the adiabatic flame temperature of the premixed flame provided in the gas turbine combustor between about 1650 to 1970 K is a necessary operating condition for eliminating the need for a denitration device.

An example of the experimental results that led to the present invention will be described below. FIG. 14 shows that the air preheating temperature is 29
8K to 667K, air ratio 0.7 to 1.9, air humidity 0.7.
[0094] The experimental results obtained by changing the ejection speed in the range of 5 to 12 n / s and the adiabatic flame temperature and NO
It is arranged in relation to x emission concentration. The numbers indicated by arrows at the measurement points in the figure are the air ratios. The air ratio of the measurement points without numbers is 1.2 to 1.9. Regarding an excess air flame having an air ratio of 1.05 or more, when the same fuel is used, if the flame temperature is the same, the NOx concentration is substantially the same even if the air preheating temperature, the air ratio, and the air humidity are different. is there. That is, if the combustion state is controlled so as to keep the flame temperature constant, the NOx concentration can always be kept low even if the air preheating temperature, the air ratio, and the air humidity change.

However, for a flame having an air ratio of 1.0 or less,
Since there is no correlation between the maximum flame temperature and the NOx concentration, the above-described method of controlling the combustion state is effective when forming a flame with excess air.

In FIG. 14, methane and propane were used as fuel. As can be seen from the figure, even if the flame temperature is constant, the NOx concentration changes if the fuel properties are different. NOx is easily emitted from propane flame, and when compared at the same flame temperature, the NOx concentration from the methane flame is about 2
5% higher. Further, in order to make the same as the NOx concentration from the methane flame, it is necessary to lower the flame temperature by 30 to 40K.

FIG. 15 is a graph showing NOx when the fuel composition is changed.
This is a result of organizing the concentration by the average number of carbon atoms in one fuel molecule. The NOx concentration from the ethane flame is almost the same as when the methane-propane mixed fuel having the same average carbon number is used, as in the case of organizing the fuel calorific value. from this result,
It is understood that the NOx concentration when the flame temperature is kept constant and the fuel composition is changed can be almost determined even if the fuel composition is unknown, if the calorific value of the fuel or the average number of carbon atoms in one fuel molecule is known.

FIG. 16 shows the relationship between the CO emission concentration and the air ratio measured by changing the air preheating temperature, the air humidity, and the fuel composition. When the air ratio is around 1.2, no CO is emitted from any of the flames.
The emission concentration increases rapidly. However, the air ratio at which the CO emission concentration sharply increases differs depending on the air preheating temperature, air humidity, and fuel composition.

FIG. 17 shows the results of FIG. 16 arranged by adiabatic flame temperature. The flame temperature when the CO emission concentration rises sharply is almost constant irrespective of the difference between the air preheating temperature, the air humidity, and the fuel composition. When the fuel composition is the same, the absolute value of the CO emission concentration can be substantially determined if the flame temperature is known.

FIG. 18 summarizes the relationship between the adiabatic flame temperature at which oscillating combustion occurs and the ejection speed. As for the oscillating combustion conditions, when the flame temperatures are arranged in the same manner as in the blowout limit shown in FIG. 13, one curve is obtained for each combustor.

The following conclusions are obtained by summarizing the above results.

(A) For a premixed flame having an air ratio of 1.05 or more using the same combustor, burner, and flame holding means, the combustion state is organized according to the flame temperature. The generation conditions are almost fixed without depending on the fuel composition, air humidity, and preheating temperature. If the calorific value of the fuel or the average number of carbon atoms in one molecule of the fuel is known, the NOx emission concentration is almost determined.

(B) Therefore, if the amount of fuel and / or the amount of air supplied to the burner is controlled so that the flame temperature does not change even if the fuel composition, air humidity, and preheating temperature change, the flame blows out and CO No generation or generation of oscillating combustion occurs.
Further, a change in the NOx emission concentration due to a change in the fuel composition can be minimized.

(C) When the effect of the calorific value of the fuel or the average number of carbon atoms in one molecule on the NOx emission concentration when the flame temperature is constant is known, and the combustion state is controlled as shown in (b) The NOx emission concentration is determined by detecting the change in the calorific value of the fuel or the average number of carbon atoms in one molecule of the fuel. Therefore, the amount of ammonia supplied to the flue gas denitration device is also determined.

[0073]

According to the present invention, a change in NOx emission due to a change in atmospheric temperature, humidity, fuel composition and the like is minimized, and a low N
Ox, and can maintain good flame stability.

[Brief description of the drawings]

FIG. 1 is a system diagram of a gas turbine power generator according to a first embodiment.

FIG. 2 is a conceptual diagram showing a combustion control method of a gas turbine combustor and a control method of an ammonia flow supplied to a denitration device.

FIG. 3 is a diagram showing an example of a method for determining a fuel flow, a fuel distribution, and an air flow distribution to be supplied to a gas turbine combustor by a control device that is a basis of the present invention.

FIG. 4 is a diagram illustrating an example of a function input to a control device, the function being a function of the relationship between the flame temperature and the NOx emission concentration.

FIG. 5 is a diagram illustrating an example of a function input to a control device, which is a function of a relationship between a change in NOx emission concentration and a fuel calorific value ratio when the flame temperature is constant.

FIG. 6 is a diagram illustrating an example of a function input to a control device, which is a function of a relationship between an ejection speed and a flame temperature at which blowout occurs.

FIG. 7 is a diagram illustrating an example of a function input to the control device, which is a function of a relationship between a dilution air amount ratio and a flame temperature at which blow-off occurs.

FIG. 8 is a diagram showing another example of a method for determining a fuel flow, a fuel distribution, and an air flow distribution to be supplied to a gas turbine combustor by a control device according to another example of the present invention.

FIG. 9 shows an example of a method for determining a fuel flow rate, a fuel distribution, and an air flow rate distribution to be supplied to a gas turbine combustor by a basic control device when a gas turbine power generator including a combustor having a diffusion combustion burner is used. FIG.

FIG. 10 is a diagram showing an example of a display method of a combustion diagnosis result.

FIG. 11 is a conceptual diagram showing an example of a method of predicting changes in a gas turbine load, air humidity, and fuel calorific value and controlling a combustion state.

FIG. 12 is a diagram showing a relationship between adiabatic flame temperature and NOx emission concentration.

FIG. 13 is a diagram showing a relationship between adiabatic flame temperature and ejection speed.

FIG. 14 is a view showing the relationship between the flame temperature of a premixed flame and the NOx emission concentration.

FIG. 15 is a view showing the relationship between the average carbon number in one molecule of fuel and the NOx emission concentration when the flame temperature of the premixed flame is constant.

FIG. 16 is a diagram showing the relationship between the air ratio of the premixed flame and the CO emission concentration when the air temperature, humidity, and fuel composition are different from each other.

FIG. 17 is a diagram showing the relationship between the flame temperature of a premixed flame and the CO emission concentration.

FIG. 18 is a diagram showing the relationship between the ejection speed and the flame temperature at which oscillating combustion occurs when the air temperature, humidity, and fuel composition are different.

[Explanation of symbols]

1 ... fuel calorific value measuring device, 2 ... fuel flow rate measuring device, 5 ...
Air pressure measuring device, 6 ... Gas turbine combustor inlet gas temperature measuring device, 7 ... Air flow measuring device, 8 ... Atmospheric temperature and humidity measuring device, 15 ... Ammonia flow measuring device, 19 ...
Moisture content measuring device for fuel, 21 gas turbine combustor, 24 air compressor, 25 gas turbine, 26 generator, 27 steam turbine, 28 denitrification device, 39 fuel tank, 40 fuel nozzle.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tadataka Murakami 4026 Kuji-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. Hitachi, Ltd., Hitachi Plant (72) Inventor Shigeru Azumidahata 3-1-1, Sakaimachi, Hitachi, Ibaraki Prefecture Hitachi, Ltd., Hitachi Plant (56) References JP-A-2-33419 (JP, A) JP-A Sho JP-A-51-5634 (JP, A) JP-A-52-84309 (JP, A) JP-A-7-57822 (JP, A) JP-A-3-36409 (JP, A) JP-A-61-212317 (JP, A) A) JP-A-63-88021 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23C 11/00 F23C 1/02

Claims (6)

(57) [Claims] 1. A combustor having a premixed combustion burner for emitting a mixed flow of fuel and air to form a flame, a compressor for supplying air to the burner, and a combustion gas discharged from the combustor. A gas turbine connected to the air compressor to be driven, a central operation room for sending a control command to a combustor in accordance with a load change of the gas turbine, and a generator connected to the gas turbine. In the gas turbine power generator, the calculated value of the flame temperature obtained based on the composition of the fuel flowing into the burner, the moisture concentration of the air, the temperature of the air, and the air ratio may be set in advance according to the load of the gas turbine. A gas turbine power generator, comprising: combustion control means for controlling the amount of fuel and / or air supplied to the burner so as to fall within the range. 2. A flame formed by a load of a gas turbine and an amount of air supplied to the premixed combustion burner to a control unit of the central operation room, and a flame formed by the load of the gas turbine and the premixed combustion burner. A gas turbine power generator, comprising: a program for associating the temperature with the temperature or the adiabatic flame temperature. 3. A flame formed by a fuel calorific value, a measurement result of air humidity and an air temperature, an amount of air supplied to the premixed combustion burner, a load of a gas turbine, and a flame formed by the premixed combustion burner. Means for determining at least one of a fuel supply amount, a fuel distribution ratio to each burner, and / or an air distribution ratio to each burner based on a program relating the temperature of the fuel or the adiabatic flame temperature. Characteristic gas turbine power generator. 4. The method of claim 1, comprising a flue gas denitration apparatus of reacting with the nitrogen oxides in the combustion exhaust gas discharged the reducing gas from the gas turbine, the heating value of the fuel when the flame temperature is the same, or Average carbon number and NOx in one fuel molecule
A gas turbine power generator, characterized in that a control unit of the flue gas denitration apparatus is provided with a program that associates the relation with the emission concentration. 5. A control method for a denitration device connected to a combustion device having a load request signal output means and discharging exhaust gas discharged from the combustion device to the atmosphere, wherein the control device is connected to the load request signal output means. An ammonia flow control device connected to the basic control device, and at least one of air temperature, air humidity, air pressure, fuel composition, and the amount of water supplied to the combustion device is output to the load request signal output means or the ammonia. A method for controlling a denitration device, comprising: correcting a signal input to a flow rate control device to control an ammonia injection amount. 6. A control device for a denitration device connected to a combustion device provided with a load request signal output means and discharging exhaust gas discharged from the combustion device to the atmosphere, wherein the load request signal output means and basic control Connect with the device,
The basic control device and the ammonia flow control device are connected, and at least one of air temperature, air humidity, air pressure, fuel composition, and the amount of water supplied to the combustion device is output to the load request signal output means or the ammonia flow rate. A control device for a denitration device, comprising: means for inputting to a control device; and means for correcting a signal for controlling an ammonia injection amount based on the input value input.