JPH0445652B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a monitoring device for a combustor of a gas turbine. In particular, the present invention relates to a gas turbine combustor monitoring device that can be effectively applied to multi-tube combustion type gas turbines, and can also be applied to combustors of various other types.

[Background of the invention]

Knowing the combustion state of the gas turbine combustor,
In other words, in order to monitor the combustor, it is necessary to know the combustion gas temperature within the combustor. However, since the temperature of combustion gas is extremely high at over 1000°C, direct measurement inside the combustor is extremely difficult.
Even if it were possible to measure it, it would be impossible to measure it continuously for a long time. This is because it is impossible to install a temperature sensor that can withstand such high temperature conditions for a long time. Additionally, if a temperature sensor is installed inside the combustor, there is a risk that it may peel off or break and flow into the turbine, causing an accident. Should be avoided. Therefore, at present, it is common practice to determine whether the combustor is normal or abnormal by measuring the temperature of the low-temperature (around 500℃) exhaust gas that has done work downstream of the combustor in the gas turbine. (combustor damage, misfire). In this case, if the combustor is normal, the exhaust gas temperature shows almost the same distribution, and if there is an abnormality in the combustor, the abnormality can be detected because the exhaust gas temperature becomes locally low. However, in this method, abnormalities in the combustor are determined by measuring the temperature at positions downstream of the combustor, so the temperature distribution does not change significantly unless the combustor is severely damaged. The problem is that abnormalities cannot be detected unless they cause damage. In addition, in a multi-tube combustion type gas turbine, all the combustion gas from the combustor of each cylinder flows into the turn section, and as a result of the combustion gas being disturbed by the rotation of the turbine blades and stator blades, each The abnormality of the combustor will be diluted, so to speak. Therefore, in practice, it is impossible to determine an abnormality unless a significant number of combustors are extensively damaged or misfired. Moreover, it has the disadvantage that the sensing response is slow.

FIG. 1 is an explanatory diagram of a multi-tube combustion type gas turbine. Based on this figure, the conventional example will be described in more detail. In this figure, a plurality of combustors 4a having the same shape and size are installed on the circumference of the rotor 11. Air 2 compressed by the compressor section 1 of the gas turbine passes through the turbine casing 3, flows into the combustor outer cylinder 4, and then flows into the combustor inner cylinder 5. Here, it is mixed and diffused with the fuel sprayed from the fuel nozzle 6, ignited by the spark plug 7, and combusted. The combustion gas 8 is transferred to the combustor inner cylinder 5
It flows into the turbine section 10 through the interior and transition piece 9 and rotates the rotor 11. Thereafter, the combustion gas 8 becomes exhaust gas 12 and is released into the atmosphere. The temperature measurements for general combustor monitoring described above are made at a location just before the exhaust gas 12 is released to the atmosphere. Therefore, it is only possible to grasp a state that is quite different from the gas state in the combustor 4a, and for this reason, various drawbacks and problems arise regarding combustor monitoring as described above.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned conventional drawbacks, to enable accurate and detailed monitoring of the combustor by accurately sensing the state of the combustor inner cylinder, and to provide a reliable monitoring device. It is an object of the present invention to provide a combustor monitoring device that is highly efficient and can also improve the reliability of operation and maintenance of a gas turbine.

[Summary of the invention]

The combustor monitoring device of the present invention measures the pressure difference between the inside and outside of the combustor and the change in combustion oscillation pressure that occurs during combustion for each combustor, instead of monitoring by temperature measurement, which is commonly performed. This feature is characterized in that the combustor is monitored by doing so.

[Embodiments of the invention]

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

FIG. 2 is a diagram showing one embodiment of this. This gas turbine combustor monitoring device measures the pressure difference P _C - P _B inside and outside the combustor and changes in combustion oscillation pressure within the combustor, and determines the state of the combustor based on these measured values. This is a configuration for monitoring.

Therefore, the condition can be directly known from the data of the pressure within the combustion, rather than the temperature of the exhaust gas as in the conventional case, so that accurate monitoring can be achieved. Moreover, since data on each combustor can be directly obtained, even if an abnormality occurs, it can be diagnosed quickly.

More specifically, the specific configuration of this embodiment is as follows. In FIG. 2, the compressed air compressed by the compressor section is transferred to the combustor outer cylinder 20.
guided inward. Next, air flows into the combustor inner cylinder 21 through a large number of air holes 22 provided in the axial and circumferential directions of the combustor inner cylinder 21, which is installed approximately concentrically within the combustor outer cylinder 20. Inflow. The air that has flowed in is mixed with the fuel injected from the fuel nozzle 23, diffused, and ignited by some means to burn, producing combustion gas. A flange 25 is attached to the outer periphery of the combustor outer cylinder 20 by welding (or equivalent means), and thereby a tube 24 having a diameter of about 10 mm or less is held so as to protrude into the combustor outer cylinder 20. A fitting connector 26 for positioning and fixing the tube 24 within the combustor outer cylinder 20 is screwed and fixed to the flange 25. The tube 24 is located between the inner side 20a of the combustor outer cylinder 20 and the combustor inner cylinder 21.
On one side of the space 28 formed by the outer side 21a, it is set and fixed at approximately 1/2 the position in the radial direction. This tube 24
, one end 24a is connected to the combustor outer cylinder 20 in this way.
The other end is guided to the pressure sensor 27. Due to this,
The pressure within the tube 24 becomes equal to the pressure in the space 28 within the combustor sheath 20. At the same time, this space 28
The pressure is measured by a pressure sensor 27. This pressure P _C is approximately equal to the pressure of compressed air 19 compressed in the compressor section. In addition, this pressure P _C shall be measured in each combustor in the case of a multi-tube combustion type combustor. (This will be discussed in detail in the next example with reference to FIG. 3).

Further, a tube 29 is provided on the outer periphery of the combustor outer cylinder 20 by the same means as described above.
One end 29a of this tube 29 is inserted all the way into the combustor inner cylinder 21, unlike the case described above. In this case, by using a large number of air holes 22 provided in the combustor inner cylinder 21, or by adding a dedicated hole for insertion,
One end 29a of the tube 29 is inserted into the combustor inner cylinder 21. Generally, it is preferable to use the existing air holes 22 because providing a dedicated hole for insertion may change the combustion characteristics of the combustor. Since there is a difference in the amount of elongation due to thermal expansion between the combustor outer cylinder 20 and the combustor inner cylinder 21 during operation, the air hole 22 into which the tube 29 is inserted is designed to accommodate the difference in thermal elongation from the outer diameter of the tube 29. The air hole 22 has a diameter such that the tube 29 will not come into contact with the combustor inner cylinder 21 even if this is taken into consideration. The other end of this tube 29 is connected to the
pressure sensors 30 and 3, respectively.
1 is installed. The pressure within the tube 29 up to the pressure sensors 30 and 31 is made equal to the pressure within the combustor inner cylinder.

It is known that normally, when the flow path of air suddenly changes, a pressure drop occurs due to friction loss in the flow path and the like. Due to a similar phenomenon in the combustor of a gas turbine, the pressure of the compressed air 19 that has flowed into the space 28 in the combustor outer cylinder 20 decreases in pressure when it flows into the combustor inner cylinder 21 through the air hole 22. occurs. As a result, the pressure within the combustor inner cylinder 21 becomes lower than that of the compressed air 19. This pressure drop is
Usually, it is 3 to 4% due to the design of the combustor.
From this, the combustor outer cylinder 20 is
By measuring the pressure P _C in the inner space 28 and the pressure P _B in the combustor inner cylinder 21 and calculating the pressure difference P _C −S _B , the state of the combustor can be grasped. (still,
The amount of insertion of the tube 29 for measuring the pressure inside the combustor inner cylinder 21 should be about 5 mm from the inner wall of the combustor inner cylinder 21, as if it is too deep, the tube will come into contact with the flame of combustion gas and burn out or melt. Insert it. ) It is also known that combustors produce combustion oscillations as a unique phenomenon. This is because when combustibles are mixed with air and combusted in a limited space (in this case, inside the combustor cylinder), a combustion reaction occurs because the mixing state of the combustibles and air differs depending on the location. Variations in time occur, which cause the air in the space to vibrate, resulting in vibrations in the air column that result in pressure fluctuations that can be sensed. This means that when there is no combustion, the fluctuation level (combustion oscillation value) is very low, and even when there is combustion,
During normal combustion, the combustion oscillation value is perceived as relatively low. However, during abnormal combustion, the combustion oscillation value becomes extremely high. Therefore, one branched end of the tube 29 inserted into the combustor inner cylinder 21 measures the internal pressure P _B of the combustor inner cylinder 21,
It is used to calculate the pressure drop of the combustor, but if the combustion oscillation value P _A is measured using the other method,
This will allow you to understand the combustion status.

Therefore, in this embodiment, as described above, the pressure difference P _C -P _B between the inside and outside of the combustor is determined by the detection of the pressure P C outside the combustor inner cylinder 21 by the tube 24 and the pressure sensor 27, and the detection of the pressure P _C outside the combustor inner cylinder 21 by the tube 24 and the pressure sensor 27. Measured by detecting the pressure P _B of the combustor inner cylinder 21a with the pressure sensor 30,
This data was used to determine the combustion status of the combustor. Furthermore, the combustion vibration value within the combustor is measured by the tube 24 and the pressure sensor 31, and the combustion state can be determined from this data.

Both types of data make it possible to directly and accurately grasp the combustion state of each combustor.

FIG. 3 shows another embodiment of the present invention, which is a system diagram showing an example in which the present invention is applied to a multi-tube combustion type combustor. In this figure, the output signals of combustor external cylinder internal pressure P _C , combustor internal cylinder internal pressure P _B , and combustion oscillation value _PA obtained from each combustor are as follows:
Each combustor is guided to a combustion state determination device 33. Here, the signals are discriminated, and if necessary, the turbine trip device 33a performs an operation to trip (abnormally stop) the turbine, and each display 33b displays the current status of each combustor. There is. Judgment as to whether or not the combustion state is abnormal in each case is made in the same manner as explained in the previous embodiment.

FIG. 4 is a system diagram for explaining the inside of the combustion state abnormality determination device 33. The pressure output signals P _A , P _B , P _C measured from each combustor are outputted to the discriminator 3
It leads me to 4,35. The discriminators 34 and 35 store initial operating values and design tolerances at various gas turbine loads. The stored data can be immediately compared with measured data. Regarding the combustion oscillation value P _A ,
The discrimination reference value P _{d nio} ~ _{P d nax} is calculated based on the data from the initial operation when the combustor was normal and the design allowable value, depending on the load at that time, and this value and the input signal value P _A We are starting to compare the
Furthermore, P _{a nio} to P _{a nax} are similarly determined for the combustor outer cylinder internal pressure P _C and the inner cylinder internal pressure P _B . Discriminator 35 between outer cylinder internal pressure P _C and inner cylinder internal pressure P _B
Comparisons within are made using the pressure drop, that is, the value of P _C −P _B .

The results obtained by the discriminator are determined depending on whether the value is below the reference value, within the range of the reference value, or exceeds the reference value, as shown in Figure 4.
Output in the case of is the combustion oscillation pressure P _A
is below the standard value, is also within the standard value, and is above the standard value. is the case where the combustor pressure difference P _C − P _B is below the standard value,
is also within the standard value, and is also above the standard value. Based on these results, ~
Each display is made with the necessary and sufficient conditions that both up to and through hold true. In other words, if both are normal (within tolerance)
If the combustion vibration is very low and the pressure drop is normal (and is), it is assumed that combustion is not occurring and a misfire is displayed. Similarly, if the combustion vibration is large and the pressure drop is normal (and is), abnormal combustion is displayed.

To specifically express the combustion oscillation value using numerical values, the combustion oscillation value is zero when there is no combustion, and is within the range of 0.02 to 0.35 Kg/cm ² during normal combustion. Furthermore, during abnormal combustion, the combustion oscillation value becomes larger than 0.035Kg/cm ² because the combustion is unstable. Therefore, it is possible to understand the combustion state from the above.

If the pressure drop changes, for example if the pressure drop decreases or becomes clogged, it means that the amount of compressed air flowing in has increased due to an increase in the flow path area, which may cause cracks or defects in the combustor inner cylinder. is possible. Therefore, a crack occurs and it is displayed as defective. The difference between crack occurrence and defects can be understood in more detail by paying attention to changes in combustion vibration. That is, when a crack occurs, the increase in the amount of air flowing in is not very large and there is no significant change in the combustion state, so the combustion oscillation value hardly changes. However, when a defect occurs, the combustion state becomes unstable due to a sudden increase in the amount of air inflow, and combustion vibration increases. From this, it is possible to further distinguish and detect both crack occurrence and defects by combining the combustion vibration discrimination result with the decrease in pressure drop.

Furthermore, if the pressure drop becomes large and the blockage occurs, the flow path resistance may increase due to a decrease in the flow path area, and foreign matter in the air or impurities contained in the fuel oil may be present in the combustor inner cylinder air hole. Since there is a possibility that the air hole is clogged, it is now indicated that the air hole is clogged. Based on various displays, a turbine trip instruction is displayed to stop the turbine depending on the situation.

It should be noted that more accurate monitoring may be possible if the discrimination reference value is changed from time to time, taking into account changes over time based on data during operation after the combustor inspection results.

In view of the above, in this embodiment, the combustor is monitored with necessary and sufficient conditions for measured values, so that the state of the combustor can be grasped in extremely detailed and accurate manner. Such detailed and accurate understanding is completely impossible with conventional technology.

〔Effect of the invention〕

As described above, according to the present invention, since the state of the combustor can be directly measured at the combustor, the state of the gas turbine combustor can be accurately and accurately grasped in detail. Therefore, the reliability of the combustor monitoring device is improved, and more accurate diagnosis becomes possible, which has the effect of improving the reliability of gas turbine operation and maintenance.

It goes without saying that the present invention is not limited to the illustrated embodiments.

[Brief explanation of the drawing]

FIG. 1 is a drawing for explaining a conventional example, and is a diagram showing the configuration around a general combustor. FIG. 2 is a sectional view of essential parts showing the first embodiment of the present invention. FIG. 3 is a system diagram showing a system of a monitoring device according to a second embodiment of the present invention. FIG. 4 is a partial detailed system diagram of the monitoring device.

Claims (1)

[Claims] 1. A device for monitoring the combustor of a gas turbine, which measures the pressure difference between the inside and outside of the combustor and the change in combustion oscillation pressure within the combustor, and determines the state of the combustor based on these measured values. A combustor monitoring device for a gas turbine, characterized in that it is configured to monitor. 2. Setting reference values for both the pressure difference and the combustion oscillation pressure fluctuation value, and monitoring the state of the combustor based on the deviation from the reference value of the measured value of the change in the pressure difference and combustion oscillation pressure. A combustor monitoring device for a gas turbine according to claim 1, characterized in that the combustor monitoring device is configured as follows. 3 Setting reference values for both the pressure difference and the combustion oscillation pressure fluctuation value, and monitoring the state of the combustor under necessary and sufficient conditions for the reference value of the measured value of the pressure difference and the change in the combustion oscillation pressure. A combustor monitoring device for a gas turbine according to claim 1, characterized in that the combustor monitoring device is configured as follows. 4. A gas turbine combustor according to any one of claims 1 to 3, characterized in that in a gas turbine having a plurality of combustors, each combustor is provided with the monitoring device. Monitoring equipment.