JPH06264772A - Gas turbine and operation thereof - Google Patents

Abstract

PURPOSE:To prolong the life span by way of reducing ununiformity of gas temperature and preventing high frequency thermal shock by separately controlling an overall air flow rate and an overall fuel flow amount of each combustor by way of measuring gas temperature at outlet parts of a plural number of the combustors and thereafter, in accordance with the result of this measurement. CONSTITUTION:A gas turbine is furnished with a plural number of combustors 42. In this case, at the time of driving the gas turbine, temperature at an outlet part of each of the combustors 42 is respectively measured by each gas temperature sensor 41. Thereafter, in accordance with each measured gas temperature, by a control judgement device 45, an air flow rate control device 43 and a fuel flow rate control device 44 are respectively controlled. Consequently, it is possible to prevent generation of ununiformity in gas temperature and to lengthen a life span by preventing a turbine blade from causing thermal embrittlement due to high frequency thermal shock.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine having a plurality of combustors, and more particularly to preventing thermal embrittlement of turbine blades due to high frequency thermal shock caused by nonuniform temperature of gas flowing out from each combustor. And a method of operating the same.

[0002]

2. Description of the Related Art A conventional technique for a gas turbine having a plurality of combustors will be described.

The air taken in from the outside is compressed by the compressor, enters the compressed air chamber, and flows into each combustor.
In the compressed air chamber, the combustors are annularly arranged, and the symmetrical arrangement of the combustors equalizes the amount of compressed air flowing into each combustor. The compressed air that has flowed into the combustor is mixed with fuel and combusted, and passes through the combustor outlet as a high-temperature burned gas to enter the turbine body to rotate the turbine at a high speed. At this time, the high-temperature gas from each combustor flows into the turbine from a region corresponding to each combustor in which the circumference of the turbine is divided. This conventional technique is disclosed in JP-A-48
-64310, etc. In such a gas turbine, each part of the turbine blade receives the hot gases from the plurality of combustors alternately as the turbine rotates at high speed. Therefore, when there is a difference in the high temperature gas temperature of each combustor, each part of the turbine blade is subjected to high-frequency thermal shock, which shortens the life of the turbine blade.

In order to prevent the high-frequency thermal shock on the turbine blade according to the prior art, a mechanism for optimizing the combustion state of the combustor to make the temperature of the hot gas from each combustor uniform is disclosed in Japanese Patent Laid-Open No. Sho 61-61. As described in JP-A-210233, the total fuel flow rate entering each combustor is controlled by adjusting a fuel control valve provided for each combustor, and the air flow rate distribution and the fuel flow rate distribution of each combustor are controlled. By so doing, combustion was optimized and the temperature of the high temperature gas flowing into the turbine from each combustor was made uniform.

[0005]

However, in the prior art, the total air flow rate flowing into the combustor cannot be controlled for each combustor, and the gas temperature of each combustor is prevented so as to prevent high-frequency thermal shock applied to the turbine blades. There was a problem that the optimization of the combustion state for homogenizing was not sufficiently achieved.

It is an object of the present invention to reduce the non-uniformity of the temperature of the gas flowing out from each combustor, reduce the high frequency thermal shock on the turbine blade, and improve the life of the turbine blade and the gas turbine operating method. To provide.

[0007]

A first gas turbine operating method according to the present invention is a gas turbine having a plurality of combustors.
In the bin, the operating method is to control the total air flow rate and the total fuel flow rate of each combustor, and the air flow rate distribution and the fuel flow rate distribution in each combustor based on the gas temperature at the outlet of each combustor.

A second gas turbine operating method according to the present invention is the operating method of the first gas turbine operating method, wherein each gas temperature is controlled so as to fall within a desired allowable temperature range.

A third gas turbine operating method according to the present invention is the operating method of the first gas turbine operating method, wherein each gas temperature is controlled to be uniform.

According to a fourth method of operating a gas turbine of the present invention, in a gas turbine having a plurality of combustors, the total air flow rate of each combustor is determined based on the gas temperature flowing out from each combustor and passing through the turbine. This is an operating method for controlling the total fuel flow rate, the air flow rate distribution in each combustor, and the fuel flow rate distribution.

A fifth gas turbine operating method according to the present invention is the operating method of the fourth gas turbine operating method, wherein each gas temperature is controlled so as to fall within a desired allowable temperature range.

A fifth gas turbine operating method according to the present invention is the operating method of the fourth gas turbine operating method, wherein each gas temperature is controlled to be uniform.

A first gas turbine according to the present invention has a plurality of combustors, a sensor section for measuring a gas temperature is provided at an outlet section of each combustor, and each combustion is performed based on the measured value of the sensor section. It is configured by providing a device for determining the air flow rate distribution between the burners and the fuel flow rate, a device for controlling the air flow rate of each combustor based on the result of the device, and a device for controlling the fuel flow rate of each combustor.

A second gas turbine according to the present invention has a plurality of combustors, is provided with a sensor section for measuring the gas temperature flowing out from each combustor and passing through the gas turbine, and the measured value of the sensor section is set. By providing a device for determining the air flow rate distribution and fuel flow rate between each combustor based on the above, a device for controlling the air flow rate for each combustor based on the result of the device, and a device for controlling the fuel flow rate for each combustor Composed.

[0015]

According to the first gas turbine operating method, the combustion state of each combustor is known by measuring the gas temperature at the outlet of each combustor, and the thermal shock is applied to the turbine blade by changing the air flow rate and the fuel flow rate. It is possible to control the gas temperature at the outlet of each combustor so as not to apply heat, and to prevent thermal shock applied to the turbine blades.

According to the second gas turbine operating method, in the first gas turbine operating method, the thermal shock applied to the turbine blade is reduced by controlling the gas temperature at the outlet of each combustor within a desired allowable range. can do.

According to the third gas turbine operating method, by the action of the first gas turbine operating method, it is possible to eliminate the thermal shock applied to the turbine blade by uniformly controlling the gas temperature at each combustor outlet. it can.

According to the fourth gas turbine operating method, the combustion state of each combustor is known by measuring the temperature of the gas flowing out from each combustor and passing through the gas turbine. By changing the flow rate, the gas temperature at each combustor outlet can be controlled, and thermal shock on the turbine blades can be prevented.

According to the fifth gas turbine operating method, the thermal shock applied to the turbine blade is controlled by controlling the gas temperature at each combustor outlet within a desired allowable range by the action of the fourth gas turbine operating method. Can be reduced.

According to the sixth gas turbine operating method, by the action of the fourth gas turbine operating method, it is possible to eliminate the thermal shock applied to the turbine blade by uniformly controlling the gas temperature at each combustor outlet. it can.

According to the first gas turbine, the first to third gas turbine operating methods can be realized, and the thermal shock applied to the turbine blade can be prevented.

According to the second gas turbine, the fourth to sixth gas turbine operating methods can be realized, and the thermal shock applied to the turbine blade can be prevented.

[0023]

FIG. 1 shows a flow chart of a first embodiment of the operating method of the present invention. Start the gas turbine (step 1). The gas temperature is measured (step 2). After measuring the gas temperature, determine whether control is necessary (step 3), and if necessary, total air flow rate and total fuel flow rate of each combustor,
And controlling the air and fuel distribution between the combustors (step 4). After that, if the gas turbine is judged to be stopped (step 5), if it is stopped, it is stopped as it is (step 6), and if it is continuously operated, steps 2 to 5 are repeated. In the flow of this operation method, control is performed when a predetermined standard is reached by detecting the gas temperature, and unnecessary work is reduced. Considering the cause of the difference in gas temperature of each combustor, in addition to differences in air flow rate, fuel flow rate, air distribution, fuel flow rate, individual differences between combustors due to manufacturing errors, and secular change It is considered that there are individual differences in each combustor due to. Since the difference in these causes does not appear as the difference in the resulting gas temperature difference, according to the gas turbine operating method of the present embodiment, the difference in the life of each combustor due to the individual difference is reduced to the same level. Therefore, it is possible to synchronize the combustor replacement time and reduce the number of operation stoppages.

FIG. 2 shows a flowchart of a second embodiment of the operating method of the present invention. First, after starting the gas turbine (step 1), then measuring the gas temperature (step 2)
I do. After measuring the gas temperature, it is judged whether or not each gas temperature is within a desired allowable range (step 13). If it is out of the allowable range, the total air flow rate and total fuel flow rate of each combustor, and the air distribution and fuel distribution of the combustor are controlled so that each gas temperature falls within the allowable range (step 4). After that, it is judged whether the gas turbine is stopped (step 5)
When it is stopped (step 6), it is stopped as it is, and when it is continuously operated, the processes of steps 2, 4, 5 and 13 are repeated. In addition to the effect of the first embodiment, this operating method can reduce the thermal shock applied to the turbine blade by keeping the gas temperature within the allowable range. Since the gas temperature is measured in the operating method of the present invention, the absolute value of the gas temperature can be measured together with the difference in the gas temperature. Therefore, the life span of the turbine blade is further improved by considering the allowable temperature range not only by limiting the thermal shock but also by considering the upper limit for preventing thermal destruction of the turbine blade. In addition to the turbine blades, thermal embrittlement of the high temperature components can be avoided by considering the upper limit of the thermal destruction prevention of the high temperature components of the gas turbine in contact with the flow path of the burnt gas.

FIG. 3 shows a flowchart of a third embodiment of the operating method of the present invention. After starting the gas turbine (step 1), the gas temperature is measured (step 3). After measuring the gas temperature, it is judged whether or not each gas temperature is uniform (step 23). If not uniform, the total air flow rate and total fuel flow rate of each combustor, and the air distribution and fuel distribution of the combustor are controlled so that the gas temperature becomes uniform (step 4). After that, when the gas turbine is judged to be stopped, if it is stopped, it is stopped as it is (step 5), and if it is continuously operated, the processing of steps 2, 4, 5 and 23 is repeated. In this operating method, in addition to the effect of the first embodiment, the thermal shock applied to the turbine blade can be eliminated by making the gas temperature uniform.

FIG. 4 shows a block diagram of an example of measuring the gas temperature at the combustor outlet as a first embodiment of the temperature measuring method. A gas temperature sensor 41 is provided at the outlet of each combustor 42.
To measure the gas temperature. The measured signal is input to the control determination device 45. The control determination device 45 determines the control value based on the measured temperature, and the result is sent to the air flow rate control device 43 and the fuel flow rate control device 44. The air flow rate control device 43 and the fuel flow rate control device 44 control the air flow rate and the fuel flow rate according to the received signals. In this example, since the temperature of the gas flowing into the turbine is measured directly, accurate measurement can be performed. Further, FIG. 5 shows a conceptual diagram of an example of measuring the temperature of gas after passing through a turbine as a second embodiment of temperature measurement. The difference from the first embodiment of this example is that the temperature sensor 41 measures the combustion gas temperature after rotating the turbine 51. The flow of control after measurement is the same as in the first embodiment. In this example, the accuracy is inferior to that of directly measuring the gas temperature at the combustor outlet portion, but the gas temperature is lower than that at the combustor outlet portion, so that the durability of the sensor used is limited and the failure is reduced.

An embodiment of the control judgment device 45 is shown in FIG.
The measurement signal 66 of each sensor enters the average value circuit 61 and the average value of the combustion gas temperature is obtained. The subtracter 62 determines the difference between the gas temperature of each combustor and the average combustion gas temperature.
The signal of this difference enters the control judging device 63 and the control value judging device 64. The controller 65 controls according to the result of the control value determiner 64 by the signal of the control determiner 63. In the control value judging device 64, if necessary, a measured value of another physical quantity, for example, a signal 67 such as NOx or CO concentration can be inputted and used for judgment. This makes it possible to reduce the non-uniformity of the gas temperature while maintaining low NOx and CO concentrations, and prevent thermal embrittlement of the turbine blade.

An embodiment of the air flow rate distribution device is shown in FIGS. 7, 8 and 9. In the embodiment of FIG. 7, the compressed air chamber 7
3, a device for flow rate control is provided at the tip of the outer cylinder 72 of each combustor. A throttle valve 81 as shown in FIG.
The example of the opening / closing valve 91 as shown in FIG. 9 is shown. Figure 8
In the first embodiment of the air distribution device, the air distribution can be controlled by the opening degree of the throttle valve, and in the second embodiment of the air distribution device of FIG. 9, the air distribution can be controlled by the opening / closing angle of the opening / closing blade 92. In FIG. 10, a flow rate control device is provided in the compressed air chamber 73 so as to surround the transition piece 102, and the flow rate of air entering each combustor is controlled according to the opening / closing angle of the baffle plate 101.

[0029]

According to the present invention, the following effects occur.

By controlling the total air flow rate and the total fuel flow rate of each combustor individually based on the gas temperature, it is possible to prevent the gas temperature from becoming non-uniform and reduce the thermal embrittlement of the turbine blade due to high frequency thermal shock. The life can be improved. Also,
By controlling the gas temperature so as not to exceed the allowable value, it is possible to prevent thermal embrittlement of the high temperature parts of the gas turbine and improve the life. Further, by suppressing the individual difference of each combustor, making the life of each combustor uniform, and synchronizing the replacement time, it is possible to reduce the number of times the gas turbine is stopped for maintenance or the like.

[Brief description of drawings]

FIG. 1 is a flowchart of a first embodiment of a gas turbine operating method according to the present invention.

FIG. 2 is a flowchart of a second embodiment of the gas turbine operating method of the present invention.

FIG. 3 is a flowchart of a third embodiment of the gas turbine operating method of the present invention.

FIG. 4 is a block diagram of a first embodiment of a temperature measuring method according to the present invention.

FIG. 5 is a block diagram of a second embodiment of the method for measuring temperature according to the present invention.

FIG. 6 is a block diagram of an embodiment of a control determination device of the present invention.

FIG. 7 is a sectional view of a first embodiment of an air flow distribution device of the present invention.

FIG. 8 is an explanatory diagram of a second embodiment of the air flow distribution device of the present invention.

FIG. 9 is an explanatory view of a third embodiment of the air flow distribution device of the present invention.

FIG. 10 is an explanatory view of a fourth embodiment of the air flow distribution device of the present invention.

[Explanation of Codes] 1 ... Startup, 2 ... Gas temperature measurement, 3 ... Control judgment, 4 ... Control, 5 ... Stop judgment, 6 ... Stop.

Claims (8)

[Claims] 1. A method of operating a gas turbine having a plurality of combustors, wherein the total air flow rate and the total fuel flow rate of each combustor and the inside of each combustor are determined based on the gas temperature at the outlet of each combustor. A method of operating a gas turbine, comprising controlling the air flow rate distribution and the fuel flow rate distribution of the gas turbine. 2. The total air flow rate and total fuel flow rate of each combustor and the air flow rate distribution and fuel flow rate distribution within each combustor so that each gas temperature is within a desired allowable range. How to operate a controlled gas turbine. 3. A gas for controlling the total air flow rate and the total fuel flow rate of each combustor, and the air flow rate distribution and the fuel flow rate distribution in each combustor so that the temperature of each gas becomes uniform. How to operate a turbine. 4. A method of operating a gas turbine having a plurality of combustors, wherein the total air flow rate and the total fuel flow rate of each combustor and the above-mentioned each are based on the gas temperature flowing out from each combustor and passing through the turbine. A gas turbine operating method for controlling air flow distribution and fuel flow distribution in a combustor. 5. The total air flow rate and total fuel flow rate of each combustor, and the air flow rate distribution and fuel flow rate distribution in each combustor so that each gas temperature falls within a desired allowable temperature range. Method of operating a gas turbine for controlling gas. 6. A gas for controlling a total air flow rate and a total fuel flow rate of each combustor and an air flow rate distribution and a fuel flow rate distribution in each combustor so that each gas temperature becomes uniform. How to operate a turbine. 7. A gas turbine having a plurality of combustors, wherein a sensor unit for measuring a gas temperature is provided at an outlet of each combustor, and a total air flow rate of each combustor is determined based on a measured value of the sensor unit. A device for determining a total fuel flow rate, a device for controlling a total air flow rate of each combustor, a device for controlling a total fuel flow rate of each combustor, and a device for controlling an air flow rate distribution of each combustor. And a device for controlling a fuel flow rate distribution of each of the combustors. 8. A gas turbine having a plurality of combustors, wherein a sensor section for measuring the gas temperature of the burnt gas flowing out from each combustor and passing through the gas turbine is provided, and the sensor section is provided based on the measurement value of the sensor section. A device for determining the total air flow rate and the total fuel flow rate of each combustor, a device for controlling the total air flow rate of each combustor based on the result of the device, a device for controlling the total fuel flow rate of each combustor, and a combustion A gas turbine comprising: a device for controlling an air flow distribution of a combustor and a device for controlling a fuel flow distribution of a combustor.