JPH02157502A - Temperature monitoring device for boiler tube - Google Patents

Abstract

PURPOSE:To monitor the temperature of boiler tube correctly by a method wherein a computer converts the values of respective picture elements of picture data into temperatures based on the picture data consisting of the picture elements provided with values corresponding to the magnitudes of radiation energizes radiated from respective positions of boiler tubes, which are picked up by a camera, while the converted values of the temperatures are indicated on an indicating device. CONSTITUTION:When the distribution of radiation energy on the surface of a secondary superheater 2 is transmitted by the bundle 12 of optical fibers to a spectroscope 4 as a picture, the picture is analyzed spectrally into the distributions of radiation energies having wave lengths lambda1, lambda2 by filters 5, 6 and are converted into analog picture data respectively by a photoelectric conversion device 7. These analog picture data are converted by a converter 8 into digital picture data and are stored into a memory 9. The digital pictures, having wave lengths lambda1, lambda2 and stored in the memory 9, are read and sent into a computer 10 to obtain a temperature distribution and compare them with set temperatures previously determined whereby the indication of the change of the amount of a plant is transmitted to an indicating device 11 through signal cables 13. The indicating device 11 indicates the command of changing the amount of based on the indication.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for monitoring the temperature of a boiler tube of a boiler, and in particular monitors the temperature distribution of a boiler tube over a wide range and detects abnormalities such as boiler tube leaks at an early stage. This invention relates to a boiler tube temperature monitoring device suitable for preventive maintenance that provides detection and operation support.

[Conventional technology]

Conventional equipment only measures the temperature at the header of the boiler tube with a thermocouple or measures the steam temperature inside the tube, and does not measure the temperature or temperature distribution on the tube surface that comes into contact with the combustion gas. It had not been done. However, recent thermal power plants are often operated under intermediate loads with late-night startup and shutdown and large and rapid load fluctuations, and tubes, etc. that undergo large temperature changes are prone to problems such as tube leaks due to thermal fatigue. Temperature control as a form of preventive maintenance is becoming increasingly important.

Incidentally, related devices of this type are disclosed in Japanese Patent Application No. 58-221746, for example. There is one described in Japanese Patent Application No. 58-32774.

[Problem to be solved by the invention]

The boiler tube temperature in the above conventional technology is measured by measuring the temperature of each header part of the boiler tube with a thermocouple,
The temperature of boiler tubes that come in contact with combustion gas has not been measured over a wide range, so temperature control of boiler tubes is limited to This was done based on the experience and intuition of the staff.

However, in recent years, thermal power plants have been operating under intermediate loads with late-night start-ups and rapid load fluctuations, and the boiler tubes, which are subject to large temperature changes, are prone to leakage and other problems. Temperature control, such as measuring the temperature distribution of tubes, has become important for maintenance purposes.

An object of the present invention is to accurately monitor the temperature of a boiler tube and to use the method for preventive maintenance and life diagnosis.

[Means to solve the problem]

The above-mentioned problems require an imaging means for capturing light emitted by the boiler tube, a conversion means for converting the light captured by the imaging means into an electrical signal, a storage device for storing the electrical signal as image data, and the storage device. a computer that is connected to the computer and calculates the boiler tube temperature based on the image data; and a display device that is connected to the computer and displays the calculation results of the computer.

This is accomplished by a boiler tube temperature monitoring device comprising:

The boiler tube temperature monitoring device according to claim 1, wherein the imaging means is an optical fiber bundle including an objective lens and an image receiving lens.

The boiler tube temperature monitoring device according to claim 1 or 2, wherein the conversion means includes a photoelectric conversion device that converts light into an analog electrical signal, and an analog/digital conversion device that converts the analog electrical signal into a digital electrical signal. Good too.

The boiler tube temperature monitoring device according to any one of claims 1 to 3, wherein the imaging means is inserted into a cooling pipe, and the cooling pipe is attached to a furnace wall.

A spectroscope for branching the imaged light and a wavelength transmission filter connected to the spectrometer are provided between the imaging means and the conversion means, and the conversion means is connected to the wavelength transmission filter. It is good also as a boiler tube temperature monitoring device as described in 4.

The calculator includes a temperature distribution calculation means, a comparison calculation means for the set temperature and the measured temperature, a means for outputting an alarm based on the calculation result of the comparison calculation means, a temperature distribution coloring data creation means, a plant quantity change message output means, and a The boiler tube temperature monitoring device according to any one of claims 1 to 5, further comprising at least one of the life diagnosing means and means for outputting the data obtained by the means to the front claw device.

The boiler tube temperature monitoring device according to claim 6, wherein the plant amount is one or more of the following: fuel amount, air amount, water supply amount, exhaust gas recirculation amount, burner angle, and soot blower.

The boiler tube temperature monitoring device according to claim 6, wherein the remaining life diagnosis means calculates a remaining life index for remaining life diagnosis based on the measured boiler tube temperature and boiler operating time.

[Effect]

The boiler tube emits radiant energy from its surface according to its temperature. This radiant energy is captured in the form of light as an image by the imaging means, and the magnitude of the radiant energy of each pixel of this image is converted into an electrical signal by the converting means. The converted electrical signal is stored in the storage device as image data.

That is, the storage device stores image data consisting of pixels having values corresponding to the thickness of radiant energy emitted from each position of the imaged boiler tube.

Based on image data showing the magnitude of this radiant energy,
A computer converts the value of each pixel of the image data into a temperature, and outputs the signal to a display device. The output signal is displayed on a display device and is used for driving support and remaining life diagnosis.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A temperature monitoring device for a secondary superheater, which is an embodiment of the present invention, will be explained below with reference to FIG. A secondary superheater 2 is attached to the upper part of the furnace 1, and a cooling pipe 3 is attached to the furnace wall 1 at approximately the same height as the secondary superheater 2. An optical fiber bundle 12 equipped with an objective lens system and an image receiving lens system serving as imaging means is inserted into the cooling pipe 3 with the objective lens facing the secondary superheater 2, and the other end of the optical fiber bundle 12 is inserted into the cooling pipe 3. is connected to the input end of a spectrometer 4 located outside the furnace. A wavelength λ2 transmission filter 5 is connected to one of the two branched output ends of the spectrometer 4, and a wavelength λ2 transmission filter 6 is connected to the other output end. The output sides of the wavelength λ1 transmission filter 5 and the wavelength λ2 transmission filter 6 are each connected to a photoelectric conversion device N7, and the output side of the photoelectric conversion device 7 is connected to the input side of the analog/digital conversion device 8 via a signal cable 13. each connected. A photoelectric conversion device and an analog/digital conversion device constitute a conversion means. The photoelectric conversion device 7 is a monochrome ITV camera with γ correction removed. On the output side of the analog/digital conversion device 8 there is a digital image storage device 9. A computer 109 and a display device 11 are connected in series through a signal cable 13 in this order.

In the temperature monitoring device configured as described above, the radiant energy distribution on the surface of the secondary superheater 2 is transmitted as an image to the spectrometer 4 by the optical fiber bundle 12.

The image of the radiant energy distribution transmitted to the spectrometer 4 is transmitted to the wavelength λ□ transmission filter 5 connected to the spectrometer 4 and the wavelength λ
The two-transmission filter 6 separates the radiant energy into wavelengths λ1 and λ2, which are each converted into analog electrical signals by the photoelectric conversion device 7 to become analog image data.

The analog image data of each wavelength is converted into a digital electrical signal by the analog/digital converter fi8, becomes digital image data, and is stored in the digital image storage device 9. Wavelengths λ1 . The digital image of λ2 is calculated by computer 1.
0, and the temperature distribution is determined by the principle of the two-color pyrometer method. The obtained temperature distribution is compared with a predetermined set temperature, and based on the magnitude of the difference, an instruction to change the plan 1 to quantity is issued from the computer 10 via the signal cable 13, which is a signal output means. It is transmitted to the display device 11. The display device 11 displays a plant amount change instruction based on the transmitted instruction. Further, the display device 11 can also display the temperature distribution of the secondary superheater 2 calculated by the calculator 10 for each arbitrary set temperature range.

The details of the operation of the processing means included in the computer 10 will be explained below with reference to FIG.

(a) Temperature distribution calculation means 10a, each wavelength λ1. The relationship between the radiant energy of λ2 and the temperature is expressed by equations (1) and (2) based on the W i e n equation.

However, Rλ□(i-j); radiant energy at (i-j) coordinates of wavelength λ1 Rλ2 (i-j); radiant energy El at (i-j) coordinates of wavelength λ2; effective emissivity at wavelength λ. C2; Effective emissivity T (i-j) at wavelength λ2; Absolute temperature KC0 at (i-j) coordinates
;first radiation constant (=3.7403X10'erg-a&
/5) C2; second radiation constant ("1.4387cn-K)
The photoelectric conversion device 7 linearly converts radiant energy into an analog electrical signal, but it does not measure the absolute amount of radiant energy but the relative intensity, so the temperature can be calculated using the following equation (3). As shown in , the wavelength λ2. It is calculated using the ratio of radiant energy of λ.

In addition, the wavelength λ0. The effective emissivity of λ2 means that some of the radiant energy emitted from the surface of an object is absorbed by the gas etc. between the object and the objective lens of the optical fiber bundle 12.
This refers to the proportion of energy that reaches the objective lens out of the radiated energy.

By using the above formula (3), starting and stopping the boiler,
Even if the oxygen concentration in the furnace 1 changes due to load changes, etc., and the effective emissivity of the wavelength changes, the difference in the effective emissivity of the wavelengths λ1 and λ2 is considered to have a small fluctuation, so the error can be kept to a minimum. It will be done. Furthermore, although some errors are included, as shown in FIG. After calculating the relative intensity of the radiant energy of , correcting it to the absolute amount of radiant energy using the following equation (4), the temperature may be determined using the above equation (1).

γ R'λ> (i-j) = a (-Rλ1(j-j
))...(4) R'λ, (1・j); Absolute amount of radiant energy after correction Rλ, (i-j); Relative intensity of radiant energy before correction a, γ; Correction coefficient (b) Temperature distribution coloring Creation means 10b. A color is set for each arbitrary temperature range, and data for displaying the temperature distribution of the boiler tube in pseudo color on the display device 11 is created. For example, when displaying the temperature range from T to T2 in blue, and the temperature range from T to T4 in white, the temperature at each coordinate point of the temperature distribution data is made to correspond to the above colored temperature range, and according to the corresponding color, Data is set in each of the R, G, and B memories as shown in Table 1. The R, G, and B information of each coordinate point is transferred to a display device and colored.

(C) Comparison means 10c with the set temperature.

Compare the set temperature and the temperature at each point on the boiler tube. Specifically, the deviation between the set temperature T0 and the measured temperature T is determined as shown in equation (5) below.

Also, determine the maximum temperature from the temperature distribution of the boiler tube.

The minimum temperature and average temperature are determined.

ΔTt(i-j)=TotTt(i'j)
−(5) However, ΔTt(i”j); (i−j
) Coordinate temperature deviation Tot: Set temperature Tt (i-j) at time t; Temperature at (1 j) coordinate at time t When the boiler starts or stops, or when the load changes, the set temperature is Since it changes depending on the elapsed time, the set temperature for the elapsed time is the load change rate.

It is set based on past driving results, etc.

Based on the result of comparing the set temperature and the measured temperature using equation (5), the area of the boiler tube in the temperature region above the set temperature is calculated using equation (6) below.

5=Kn...(6) However, S: Area of temperature region above set temperature (a) Q: Distance from optical fiber bundle objective lens system to boiler tube (m) θ: Optical fiber bundle objective lens system Viewing angle P; Total number of pixels in the measurement field of view (d) Plant amount change message output means 10d and alarm output means 10f.

If there is an area above the set temperature in (C) above, an alarm will be output and the maximum temperature of the boiler tube will be set.

Minimum temperature, average temperature, area area above set temperature and 112
NextSuperheater temperature is high II, II Reduce the fuel amount II, 11 Lower the banner angle II, 1
1. Please reduce the amount of exhaust gas recirculation u, tt Please reduce the amount of secondary air. II. 11. Start the soot blower in the burner zone. 17. 11. Please increase the water supply flow rate.'' etc. are output on the display. do.

Based on this display, the operator changes the plant quantity in consideration of the operating state of the boiler. In the case of a warning, not only a simple image display but also an audio 2-blink signal or the like may be used.

(,) Boiler tube remaining life diagnosis means 10e. The boiler tube is managed using a function of temperature distribution at each point of the boiler tube and operating time as an index of remaining boiler tube life. the below described(
7) and (8), the remaining life [1, 2] is calculated and output to the display device 11.

The operator correlates the index with past driving performance and reflects it in driving.

L, ρ': f'Tp(t)dt...
(7) However, L engineering ρ: Remaining life index at position P 1° (amount of temperature received) L2P: Remaining life index at position P 2° (amount of temperature change received) to: Operation start time tl,; Current operation Time Tp(t); Tube temperature ΔTp(t
); Amount of change in tube temperature at position p at time t Note that the remaining life indices 1 and 2 are calculated for each position of the tube, which is set in advance.

The temperature of the boiler tube is monitored by repeating the above process. Furthermore, it is effective if the display device 11 not only displays the temperature distribution in color, but also displays trend graphs of the maximum temperature, R low temperature, average temperature, etc. with respect to the set temperature.

According to the above embodiment, since the surface temperature distribution of the boiler tube can be monitored, the temperature management of the boiler tube is facilitated, and the temperature distribution of the boiler tube at the time of starting/stopping the boiler and changing the load can be known, thereby improving the reliability of operation. improved. Also,
Temperature abnormalities can be detected early, improving safety and reducing the burden on operators. Furthermore, by comparing the data obtained with the device of this example, it became possible to diagnose the remaining life.

In addition, in the above embodiment, the imaging means is fixed, but if the tip of the optical fiber bundle equipped with an objective lens is rotatably installed, temperature monitoring in a wider range can be performed using - number of imaging means. It is also possible to do this.

Although the embodiment has been described above using the device configuration shown in FIG. 1, as shown in FIG. 4, the spectrometer 4 may be equipped with an objective lens 14 to measure the radiant energy of the boiler tube without going through an optical fiber bundle. . Also, as shown in FIG. 5, there are two optical fiber bundle spectrometers and a wavelength filter.

Photoelectric conversion device, analog/digital conversion device.

In place of the digital image storage device, a commercially available temperature distribution measuring device (Thermopure) equipped with a camera section 15 and a processor section 16 may be used.

〔Effect of the invention〕

According to the present invention, the surface temperature of the boiler tube is calculated based on the radiant energy emitted by the boiler tube, so the surface temperature of the boiler tube within the field of view of the imaging means is simultaneously monitored, and the number of monitoring points is reduced. In addition to being easy to use, it also makes it easy to detect high-temperature and low-temperature areas, which has the effect of preventing boiler tube accidents.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an overview of the device configuration of an embodiment of the present invention, FIG. 2 is a block diagram showing an overview of the configuration of a computer in the embodiment shown in FIG. 1, and FIG. 3 is an ITV as an imaging means. FIG. 4 is a perspective view showing another embodiment using a camera, FIG. 4 is a perspective view showing an example in which the device is constructed without using the optical fiber bundle of the embodiment shown in FIG. 1, and FIG. It is a perspective view showing an example. 1...Furnace, 2...Boiler tube (secondary superheater)
, 3... Cooling pipe, 4... Spectrometer, 5, 6... Wavelength transmission filter, 7... Conversion means (photoelectric conversion device), 8
...conversion means (analog/digital conversion equipment, 9.
...Storage device (digital image storage device), 10...
Computer, 11... Display device, 12... Imaging means (optical fiber bundle), 13... Signal cable, 14... Imaging means (objective lens).

Claims (1)

[Scope of Claims] 1. An imaging device that captures the light emitted by the boiler tube, a conversion device that converts the light captured by the imaging device into an electrical signal, and a storage device that stores the electrical signal as image data. A boiler tube temperature monitoring device comprising: a computer connected to the storage device to calculate a boiler tube temperature based on the image data; and a display device connected to the computer to display calculation results of the computer. 2. The boiler tube temperature monitoring device according to claim 1, wherein the imaging means is an optical fiber bundle equipped with an objective lens and an image receiving lens. 3. The conversion means comprises a photoelectric conversion device that converts light into an analog electrical signal, and an analog/digital conversion device that converts the analog electrical signal into a digital electrical signal. boiler tube temperature monitoring device. 4. The boiler tube temperature monitoring device according to any one of claims 1 to 3, wherein the imaging means is inserted into a cooling pipe, and the cooling pipe is attached to a furnace wall. 5. A spectroscope for branching the imaged light and a wavelength transmission filter connected to the spectrometer are provided between the imaging means and the conversion means, and the conversion means is connected to the wavelength transmission filter. A boiler tube temperature monitoring device according to any one of claims 1 to 4. 6. The computer includes a temperature distribution calculation means, a comparison calculation means for the set temperature and the measured temperature, a means for outputting an alarm based on the calculation result of the comparison calculation means, a temperature distribution coloring data creation means, and a plant quantity change message output means Boiler tube temperature monitoring according to any one of claims 1 to 5, further comprising at least one of the remaining life diagnosis means and means for outputting data obtained by the means to a display device. Device. 7. The boiler tube temperature monitoring device according to claim 6, wherein the plant amount is one or more of the following: fuel amount, air amount, water supply amount, exhaust gas recirculation amount, burner angle, and soot blower. 8. Boiler tube temperature monitoring according to claim 6, wherein the remaining life diagnosis means calculates a remaining life index for remaining life diagnosis based on the measured boiler tube temperature and boiler operating time. Device.