JP3852051B2 - Combustion diagnostic method and combustion diagnostic apparatus - Google Patents

Description

  The present invention relates to a combustion diagnostic method and a combustion diagnostic apparatus. More specifically, the present invention relates to a combustion diagnostic method and a combustion diagnostic apparatus that can perform combustion diagnosis with a simple configuration of the combustion state of the combustor.

  2. Description of the Related Art Conventionally, as a diagnostic system for diagnosing the combustion state of a combustor such as a gas turbine combustor, a method of spectroscopically analyzing flame emission in the combustor and estimating the combustion state from the information is known.

  In this method, generally, the flame emission is spectroscopically analyzed using an optical instrument such as a diffraction grating or a prism. However, these optical instruments are expensive and require special considerations for handling as precision instruments, so that there is a problem that setting and maintenance are not easy.

In addition, since the optical apparatus as described above is used, it is not easy to reduce the size of the apparatus, and the size and weight of the apparatus are often limited, and the vibration is often applied to an aircraft gas turbine engine, jet engine, etc. There is also a problem that it is often difficult to apply.
JP 2001-343280 A JP 2002-350235 A

  The present invention has been made in view of the problems of the prior art, and has a simple structure, vibration resistance, easy size reduction and handling, and a combustion diagnosis method and combustion diagnosis capable of grasping temporal fluctuations. The object is to provide a device.

The combustion diagnosis method of the present invention is a combustion diagnosis method for making a combustion diagnosis based on the self-light emission of a flame, and each self-light emission based on a light reception signal from each light receiving means provided corresponding to each self-light emission of the flame. The procedure for detecting the power spectrum of, the procedure for determining whether or not the peak value of the power spectrum exceeds a threshold value , and if at least one of the peak values exceeds the threshold value, combustion vibration has occurred And the following procedure.

A combustion diagnostic apparatus according to the present invention is a combustion diagnostic apparatus that performs a combustion diagnosis based on self-light emission of a flame, each light-receiving means provided corresponding to each self-light-emission of a flame, and a light reception signal from each light-receiving means And a combustion database, the arithmetic processing unit detects a power spectrum for each received light signal from each light receiving means, and from the spectral analysis unit A vibration combustion determination unit for determining combustion vibration based on at least one of the power spectrum, and the combustion database includes data necessary for determining combustion vibration from the power spectrum. To do.

Wherein said each light emission can be obtained, for example OH radicals, are CH radicals and _{C 2} radical.

  Since the present invention is configured as described above, it is possible to easily perform a flame spectral analysis without using a vibration-sensitive optical device, and to obtain an excellent effect that a combustion diagnosis can be performed based on the result. . Therefore, the excellent effect that the vibration resistance of the combustion diagnostic apparatus is improved is also obtained.

  Hereinafter, although the present invention is explained based on an embodiment, referring to an accompanying drawing, the present invention is not limited only to this embodiment.

Embodiment 1
FIG. 1 schematically shows a combustion diagnostic apparatus to which a combustion diagnostic method according to Embodiment 1 of the present invention is applied. The combustion diagnostic apparatus 1 receives, for example, a flame emission of a combustor K composed of a gas turbine combustor and outputs a signal corresponding thereto, an amplifier 3 that amplifies an output signal of the photoelectric conversion unit 2, and Based on the signal from the photoelectric conversion unit 2 amplified by the amplifier 3, the arithmetic processing device 4 that performs a calculation for diagnosing the combustion state of the combustor K, and the output device 5 that outputs a calculation result by the arithmetic processing device 4 And a combustion database 6 in which data to be referred to when the arithmetic processing unit 4 diagnoses the combustion state of the combustor K is stored in a predetermined format as a main component.

The photoelectric conversion unit 2 includes a plurality of optical sensors (light receiving means) 11, 12, and 13 having relatively high response speeds and different sensitivity wavelength ranges, and each of the optical sensors 11, 12, and 13 includes, for example, an optical fiber 7. It is configured to guide the flame emission of the combustor K. This is because flame emission in a gas turbine combustor generally includes self-emissions involving three types of molecules, such as OH radicals, C ₂ radicals and CH radicals, which are not continuous spectra. This is because it is limited to a specific wavelength range.

Here, the main light emission wavelength from the OH radical is about 260 nm (nanometers) to 315 nm (ultraviolet region), and the main light emission wavelength from the CH radical is about 427 nm to 432 nm (visible light region (blue)). ), And the main self-emission wavelength from the C ₂ radical is about 512 nm to 517 nm (visible light region (green)).

Correspondingly, the first optical sensor (hereinafter referred to as the first optical sensor) 11 is composed of an element having a sensitivity wavelength range corresponding to the main self-emission wavelength from the OH radical in the flame, and the second The optical sensor (hereinafter referred to as the second optical sensor) 12 is composed of an element having a sensitivity wavelength range corresponding to the main self-emission wavelength from the CH radical in the flame, and a third optical sensor (hereinafter referred to as the third optical sensor). (Referred to as an optical sensor) 13 is composed of an element having a sensitivity wavelength range corresponding to the main self-emission wavelength from the C ₂ radical in the flame.

  Here, as the first optical sensor 11, for example, a silicon carbide (SiC) photodiode (sensitivity wavelength range: 200 to 390 nm) is used. As the second optical sensor 12, for example, a Si photodiode (for example, S6428-01 (trade name) manufactured by Hamamatsu Photonics (sensitivity wavelength range: 400-540 nm)) having a sensitivity wavelength range adjusted in the above-described region is used. As the third optical sensor 13, for example, a Si photodiode (for example, S6429-01 (trade name) manufactured by Hamamatsu Photonics (sensitivity wavelength range: 480-600 nm)) having a sensitivity wavelength range adjusted in the above-described region is used.

  FIG. 2 shows the spectral sensitivity characteristics of a general ultraviolet sensor for reference. In the figure, a solid line L1 indicates the spectral sensitivity characteristic of the diamond light receiving element. A solid line L2 indicates the spectral sensitivity characteristic of the silicon carbide light receiving element. A solid line L3 indicates the spectral sensitivity characteristic of the gallium nitride light receiving element. A solid line L4 indicates the spectral sensitivity characteristic of the gallium phosphide light receiving element with a visible light wavelength suppression filter.

  The amplifier 3 amplifies the output signals of the optical sensors 11, 12 and 13 of the photoelectric conversion unit 2 to a necessary and sufficient level.

  FIG. 3 shows details of the arithmetic processing unit.

  The arithmetic processing unit 4 is a computer including a CPU and a memory (not shown), and causes the CPU to execute a program corresponding to processing to be described later, whereby the optical sensors 11, 12, 13 of the photoelectric conversion unit 2 amplified by the amplifier 3 are used. The flame emission of the combustor K is analyzed for each of the sensors 11, 12, and 13 based on the output of the sensor 11, that is, simply spectrally analyzed, whereby the flame emission spectrum (emission intensity) is analyzed for each sensor 11, 12, 13. A simple spectroscopic analysis unit 21 that detects each time, an air-fuel ratio detection unit 22 that detects the air-fuel ratio of the combustor K by comparing the analysis result of the simple spectroscopic analysis unit 21 with the combustion database 6, and detection by the air-fuel ratio detection unit 22 A determination unit 23 that compares the result with the combustion database 6 to determine whether there is an abnormality in the combustor K and outputs information indicating the determination result to the output device 5; It is as.

  Hereinafter, a method in which the spectral analysis unit 21 simply spectrally analyzes the flame emission of the combustor K based on the signal from the photoelectric conversion unit 2 amplified by the amplifier 3 will be described.

  The spectroscopic analysis unit 21 obtains the self-emission intensity of each radical according to the following procedure using the outputs (emission intensity (DC component)) of the optical sensors 11, 12, and 13 of the photoelectric conversion unit 2.

  For example, as described above, it is assumed that the second optical sensor 12 and the third optical sensor 13 are selected with overlapping sensitivity wavelength ranges of 480 nm to 540 nm. At this time, since only the second photosensor 12 has wavelength sensitivity with respect to CH radical self-emission (427 nm to 432 nm), when only the second photosensor 12 detects light, its output value is It shows the self-emission intensity of the CH radical.

Meanwhile, since both the sensors 12 and 13 has a wavelength sensitivity for self-emission from the _{C 2} radical (512nm~517nm), self-luminous intensity of _{C 2} radicals using those output values are determined.

Further, when both CH radicals and C ₂ radicals are self-luminous, the output value of the second photosensor 12 is the sum of the two self-luminous emission values. Therefore, by the output value of the second optical sensor 12 output value from the third optical sensor 13 (C ₂ by the radical) is subtracted, it is possible to obtain a self-emission intensity of the CH radical.

  In addition, the self-luminous intensity of the OH radical is obtained using the output value of the optical sensor 11.

  Next, a method in which the air-fuel ratio detection unit 22 detects the air-fuel ratio of the combustor K based on the self-luminous intensity of each radical obtained by the spectroscopic analysis unit 21 will be described.

As shown in FIG. 4, between the air-fuel ratio of the combustor K and the ratio of the self-luminous intensity of OH radicals, CH radicals, and C ₂ radicals (shown as OH, CH, and C2, respectively). Have a certain relationship. The combustion database 6 stores the relationship between the air-fuel ratio and the ratio of the self-luminous intensity of each radical as shown in FIG. 4 as a table or as a function. The air-fuel ratio of the combustor K is detected by comparing the analysis result with such a combustion database 6.

  Further, in the combustion database 6, not the relationship between the air-fuel ratio and the ratio of the self-luminous intensity of each radical, but the relationship between the air-fuel ratio and the output of each optical sensor 11, 12, 13 (luminescence intensity (DC component)). Information may be stored. In this case, the output (light emission intensity (DC component)) of each optical sensor 11, 12, 13 is directly input to the air-fuel ratio detection unit 22 via the amplifier 3, and the air-fuel ratio of the combustor K is detected. The However, in this case as well, the air-fuel ratio of the combustor K is still detected using the relationship between the air-fuel ratio shown in FIG. 4 and the ratio of the self-luminous intensity of each radical.

  The determination unit 23 refers to an operation state signal indicating an operation state (rotation speed, load, etc.) of the gas turbine input from a gas turbine control device (not shown), and a target sky corresponding to the operation state. By retrieving the fuel ratio from the combustion database 6 and comparing the detected air-fuel ratio with the target air-fuel ratio, the presence or absence of an abnormality in the combustor K (example of abnormality: the swirl of the swirler is damaged, The air flow rate is increased; the fuel nozzle is clogged and the fuel flow rate is decreased), and information indicating the determination result is output to the output device 5. That is, in the first embodiment, the combustion database 6 includes information about the correspondence relationship between the operating state of the gas turbine and the target air-fuel ratio.

  The output device 5 includes a monitor, an alarm device, and the like. When the determination unit 23 determines that there is an abnormality in the combustor K, the output device 5 notifies the occurrence of the abnormality using sound, light, and the like, and details of the abnormality It is assumed that information about is displayed on a monitor.

  Therefore, in the combustion diagnostic apparatus 1 of the first embodiment, the flame emission of the combustor K is guided to the photoelectric conversion unit 2 including the plurality of optical sensors 11, 12, and 13 having a relatively fast response speed and different wavelength sensitivities. Each of the photosensors 11, 12, and 13 is photoelectrically converted to the flame emission, and its output signal is amplified to an appropriate level by the amplifier 3, and the spectrum analysis unit 21 uses the amplified signal. The flame emission of the combustor K is simply spectrally analyzed, and the air-fuel ratio detection unit 22 determines the air-fuel ratio of the combustor K based on the flame emission spectrum (emission intensity (DC component)) which is the analysis result. The detection unit 23 determines whether or not there is an abnormality in the combustor K using the detection result, and the output device 5 outputs in accordance with the determination result in real time.

  Therefore, it is possible to detect in real time the fluctuation of the combustion state including the air-fuel ratio of the combustor K, and to immediately determine whether there is an abnormality. As a result, even when an abnormality occurs in the combustor K, it is possible to immediately cope with the abnormality, and it is possible to minimize adverse effects due to the abnormality.

  In addition, a plurality of optical sensors 11, 12, and 13 having vibration resistance and different sensitivity wavelength ranges can be used without using precision instruments such as diffraction gratings and prisms that are vulnerable to vibration and require special handling. Is used for simple spectral analysis by computation based on the output. As a result, the cost can be kept low, the structure is simplified despite the strong resistance to vibration, and the labor required for adjustment and maintenance of the device can be greatly reduced.

  In the first embodiment, the determination unit 23 determines whether the combustor K is abnormal based on the detection result of the air-fuel ratio detection unit 22. However, the present invention is not limited to this, and the air-fuel ratio detection unit 22 When it is possible to detect the air-fuel ratio of the combustor K with high accuracy and response speed, it is also possible to output the detection result to the control device of the gas turbine and thereby feedback control the fuel supply amount, etc. It is.

  In the first embodiment, the photoelectric conversion unit 2 is composed of a pair of optical sensors 11, 12, and 13. However, the present invention is not limited to this, and the optical sensors 11, 12, and 13 having different sensitivity wavelengths are used. For example, a set of photosensors 11, 12, 13 is assigned to each of a plurality of combustors of a gas turbine, the air-fuel ratio for each combustor is detected, and combustion is performed. When there is an air-fuel ratio imbalance between the combustors, the fuel supply amount of each combustor can be adjusted.

Embodiment 2
FIG. 5 is a functional block diagram showing a schematic configuration of the arithmetic processing unit 4A of the combustion diagnostic apparatus according to the second embodiment. As shown in the figure, the second embodiment is a modification of the first embodiment, and the arithmetic processing unit 4A can easily detect the vibration component of each light emission for each sensor 11, 12, 13 detected. The spectral analysis unit 21A is provided, and the combustion vibration determination unit 31 that determines the degree of combustion vibration of the combustor K based on the analysis result of the simple spectral analysis unit 21A is provided. The remaining configuration of the second embodiment is the same as that of the first embodiment. Hereinafter, the points of the second embodiment different from the first embodiment will be mainly described.

  The combustion vibration determination unit 31 detects the peak size in each power spectrum (vibration component (AC component)) of the flame emission of the combustor K using the analysis result of the simple spectroscopic analysis unit 21A, and the detection result is obtained. It collates with the combustion database 6, thereby determining the degree of combustion vibration, and outputs information corresponding to the determination result to the output device 5. That is, in the second embodiment, the combustion database 6 includes information indicating the relationship between the magnitude of the peak appearing in the power spectrum (vibration component (AC component)) of the flame emission of the combustor K and the degree of combustion vibration, for example, in a tabular format. Or as a function. And the combustion vibration determination part 31 determines with the combustion vibration having generate | occur | produced, when at least one of the peak values exceeds the threshold value.

  If this point is laid down, the power spectrum (vibration component (AC component)) of the flame emission becomes flat when the combustion vibration is small, and a peak corresponding to the degree appears when the combustion vibration becomes large. Therefore, the magnitude of the peak appearing in the power spectrum (vibration component (AC component)) is examined, and by comparing this with the combustion database 6, the degree of combustion vibration of the combustor K can be determined.

  That is, in the first embodiment, the air-fuel ratio detection unit 22 uses the light emission intensity of the OH radical, the CH radical, and the C2 radical, that is, the DC component of the output of each of the optical sensors 11, 12, 13. In contrast to detecting the air-fuel ratio, the combustion vibration determination unit 31 of the second embodiment uses the power spectrum of the flame emission of the combustor K, that is, the combustion vibration using the AC component of the output of each of the optical sensors 11, 12, 13. Determine the degree of.

  Such determination by the combustion vibration determination unit 31 can be performed in real time by selecting optical sensors 11, 12, and 13 that have a fast response speed. As a result, it is possible to immediately detect a sudden increase in combustion vibration, so that appropriate measures such as adjusting the resonance frequency of the combustor with a resonator to avoid combustor destruction are immediately implemented. It is also possible.

  Further, as in the first embodiment, by setting the part of the flame to be guided so as to be adapted to the sensitivity wavelength range of each of the optical sensors 11, 12, 13, the determination accuracy of the combustion vibration can be further improved. Is possible.

  As described above, the present invention has been described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made. For example, by combining the simple spectroscopic analysis unit 23 of the first embodiment and the simple spectroscopic analysis unit 23A of the second embodiment, it becomes possible to simultaneously detect the air-fuel ratio and the combustion vibration.

  The present invention is applicable when diagnosing the combustion state of, for example, a gas turbine combustor or a boiler.

1 is a block diagram schematically showing a combustion diagnostic apparatus to which a combustion diagnostic method according to Embodiment 1 of the present invention is applied. It is a graph which shows the wavelength sensitivity characteristic of the light receiving element which can be used for the same apparatus. And air-fuel ratio of the gas turbine combustor is a graph showing the relationship between the OH radicals, the ratio of the self-emission intensity of the CH radical and C ₂ radical. It is a functional block diagram which shows the detail of the arithmetic processing unit of the same apparatus. It is a functional block diagram which shows the detail of the arithmetic processing unit of the combustion diagnostic apparatus with which the combustion diagnostic method which concerns on Embodiment 2 of this invention was applied.

Explanation of symbols

K Combustor 1 Combustion diagnostic device 2 Photoelectric conversion unit 4 Arithmetic processing unit 6 Combustion database 11 Optical sensor 12 Optical sensor 13 Optical sensor 21 Simple spectroscopic analysis unit 22 Air-fuel ratio detection unit 23 Judgment unit 31 Combustion vibration determination unit

Claims (4)

A combustion diagnosis method for making a combustion diagnosis based on self-luminescence of a flame,
A procedure for detecting the power spectrum of each self-light emission based on the light reception signal from each light receiving means provided corresponding to each self-light emission of the flame,
Determining whether the peak value of the power spectrum exceeds a threshold;
And a procedure for determining that combustion vibration is occurring when at least one of the peak values exceeds a threshold value. _2. The combustion diagnosis method according to claim 1, wherein the self-light emission is an OH radical, a CH radical, and a C2 radical. A combustion diagnostic device that performs combustion diagnosis based on self-luminescence of a flame,
Each light receiving means provided corresponding to each self-light emission of the flame, an arithmetic processing device that performs arithmetic processing based on a light reception signal from each light receiving means, and a combustion database,
The arithmetic processing unit detects a power spectrum for each received light signal from each of the light receiving means, and a vibration combustion determination for determining combustion vibration based on at least one of the power spectrum from the spectral analysis unit And
A combustion diagnostic apparatus, wherein the combustion database includes data necessary for determining combustion vibration from a power spectrum. The spontaneous light, OH radical, a combustion diagnosis apparatus according to claim 3, characterized in that is a CH radical and C ₂ radical.

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