Temperature detection system and method for boiler heating surface

Abstract

The invention relates to the technical field of temperature measurement, in particular to a temperature detection system and method for a boiler heating surface. The sensor fixing device is used for fixing the fiber grating sensor on the heating surface of the target boiler; and the temperature detection device is used for guiding the target light source to enter the fiber grating sensor, receiving the multiple groups of reflection spectrum central wavelengths after multiple times of incidence, and calculating the current wall temperature of the target boiler heating surface based on the multiple groups of reflection spectrum central wavelengths. Therefore, the technical problems that in the prior art, the stability of working in a high-temperature environment for a long time is poor, distributed continuous temperature monitoring is difficult to achieve, consequently, the temperature detection result is difficult to meet the requirement for boiler refined operation management, installation is tedious, and the cost is high are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature measurement, and in particular to a temperature detection system and method for a boiler heating surface. Background Art

[0002] In the related art, a thermocouple sensor can be used to detect the temperature of the boiler heating surface tube, so as to adjust the boiler operation based on the detected temperature, thereby ensuring the boiler safety and improving the operation efficiency.

[0003] However, in the related art, when thermocouple sensors work for a long time in a high temperature environment, their stability is easily affected. In addition, in a complex boiler pipeline layout, the wiring of a large number of thermocouple sensors is extremely cumbersome, which not only increases the installation cost, but also may cause signal transmission interference and an increase in fault points due to wiring problems. In addition, it is difficult for thermocouple sensors to achieve distributed continuous temperature monitoring, and it is difficult to fully and accurately reflect the temperature field distribution of the boiler heating surface tubes. It cannot meet the high requirements for temperature monitoring in the refined operation management of modern boilers, and needs to be improved urgently. Summary of the invention

[0004] The present invention provides a temperature detection system and method for the heating surface of a boiler to solve the technical problems in the related art, such as poor stability when working in a high-temperature environment for a long time, difficulty in achieving distributed continuous temperature monitoring, which makes it difficult for the temperature detection results to meet the needs of refined operation management of the boiler, and cumbersome installation and high cost.

[0005] The first aspect of the present invention provides a temperature detection system for a boiler heating surface, comprising: a fiber grating sensor; a sensor fixing device for fixing the fiber grating sensor on a target boiler heating surface; a temperature detection device for guiding a target light source to be incident on the fiber grating sensor, receiving multiple groups of reflection spectrum center wavelengths after multiple incidents, and calculating the current wall temperature of the target boiler heating surface based on the multiple groups of reflection spectrum center wavelengths.

[0006] According to the above technical means, the embodiment of the present invention can use the sensor fixing device to install the fiber grating sensor on the boiler heating surface, and use the thermo-optical effect and thermal expansion effect of the fiber grating sensor to detect the wall temperature of the boiler heating surface by collecting the central wavelength of the reflection spectrum reflected after the target light source is incident. There is no need for complicated installation procedures, and temperature detection results that meet the needs of refined operation management of the boiler can be obtained to ensure boiler safety and improve operating efficiency.

[0007] Optionally, in one embodiment of the present invention, a high-temperature thermal conductive silicone grease coating is provided on the installation contact surface of the fiber grating sensor.

[0008] According to the above technical means, the embodiment of the present invention can discharge air with poor thermal conductivity through the high-temperature thermal conductive silicone grease coating to adapt to temperature fluctuations caused by changes in the load in the furnace.

[0009] Optionally, in one embodiment of the present invention, the sensor fixing device is a pipe clamp structure consisting of an upper clamping plate and a lower clamping plate, and an elliptical opening is provided on the sensor fixing device.

[0010] According to the above technical means, the embodiment of the present invention can use a tube clamp structure to fix the fiber optic Bragg grating sensor, which is easy to install. An elliptical opening is provided on the sensor fixing device to avoid errors caused by expansion of the tube clamp due to changes in ambient temperature, while preventing stress concentration during the manufacturing and heating process, ensuring that the tube clamp is not easily deformed.

[0011] Optionally, in one embodiment of the present invention, it further includes: a calibration module, used to calibrate the fiber grating sensor before measuring the current wall temperature using the temperature detection device.

[0012] According to the above technical means, the embodiment of the present invention can first calibrate the fiber Bragg grating sensor to calibrate the fiber Bragg grating sensor in advance to ensure the accuracy of the temperature measurement result.

[0013] Optionally, in one embodiment of the present invention, the calibration module includes: a heating unit, used to heat the target boiler until the temperature of the fiber Bragg grating sensor fixed on the heating surface of the target boiler reaches a target calibration range; a sampling unit, used to perform multiple temperature measurements within the target calibration range based on a target step size to obtain multiple groups of sampling data; and a calibration unit, used to calibrate the fiber Bragg grating sensor based on the multiple groups of sampling data to obtain the current wall temperature using the calibrated fiber Bragg grating sensor.

[0014] According to the above technical means, the embodiment of the present invention can obtain calibration signals of the fiber Bragg grating sensor at different temperatures through multiple sampling and calculation within the calibrated temperature range.

[0015] Optionally, in one embodiment of the present invention, it also includes: a compensation grating sensor that meets preset temperature and stress sensitivity characteristics; a correction device for correcting the current wall temperature based on the reflection wavelength data of the compensation grating sensor to obtain the actual wall temperature of the target boiler heating surface.

[0016] According to the above technical means, the embodiment of the present invention can correct the current wall temperature to eliminate the influence of the cross-sensitivity problem on the temperature detection result, thereby obtaining a more accurate actual wall temperature.

[0017] Optionally, in one embodiment of the present invention, the correction device includes: a first construction unit, used to construct a first relationship model between the first reflection wavelength drift of the fiber grating sensor and the temperature change and stress change; a second construction unit, used to construct a second relationship model between the second reflection wavelength drift of the compensation grating sensor and the temperature change and stress change; a calculation unit, used to calculate the corrected reflection wavelength drift based on the actual reflection wavelength drift of the fiber grating sensor, the actual reflection wavelength drift of the compensation grating sensor, the first relationship model and the second relationship model; a correction unit, used to correct the current temperature using the corrected reflection wavelength drift to obtain the actual temperature of the target boiler area to be measured.

[0018] According to the above technical means, the embodiment of the present invention can use the data of the compensation grating and the data of the fiber Bragg grating sensor under specific conditions to perform temperature correction to eliminate the influence of the cross-sensitivity problem on the temperature detection result, thereby obtaining a more accurate actual wall temperature.

[0019] The second aspect of the present invention provides a method for detecting the temperature of a boiler heating surface, comprising the following steps: guiding a target light source to be incident on a fiber grating sensor; receiving multiple groups of reflection spectrum center wavelengths after multiple incidents; and calculating the current wall temperature of the target boiler heating surface based on the multiple groups of reflection spectrum center wavelengths.

[0020] A third aspect of the present invention provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the temperature detection method for the heating surface of a boiler as described in the above embodiment.

[0021] A fourth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the temperature detection method for the heating surface of a boiler as described in the above embodiment.

[0022] A fifth aspect of the present invention provides a computer program product, including a computer program, which, when executed, is used to implement the above method for detecting the temperature of the heating surface of a boiler.

[0023] The embodiment of the present invention can use the sensor fixing device to install the fiber Bragg grating sensor on the boiler heating surface, and use the thermal optical effect and thermal expansion effect of the fiber Bragg grating sensor to detect the wall temperature of the boiler heating surface by collecting the central wavelength of the reflection spectrum reflected after the target light source is incident. There is no need for complicated installation procedures, and the temperature detection results that meet the needs of refined operation and management of the boiler can be obtained to ensure the safety of the boiler and improve the operation efficiency. Therefore, the technical problems in the related technology that the stability of long-term operation in a high temperature environment is poor, it is difficult to achieve continuous temperature monitoring, so that the temperature detection results are difficult to meet the needs of refined operation and management of the boiler, and the installation is cumbersome and the cost is high are solved.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 A schematic structural diagram of a temperature detection system for a heating surface of a boiler provided according to an embodiment of the present invention; Figure 2 A schematic flow chart of a temperature detection system for a boiler heating surface according to an embodiment of the present invention; Figure 3 A schematic diagram of a temperature calculation process according to an embodiment of the present invention; Figure 4 A flow chart of a method for detecting the temperature of a heating surface of a boiler according to an embodiment of the present invention; Figure 5 It is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0027] The following describes the temperature detection system and method of the boiler heating surface of the embodiment of the present invention with reference to the accompanying drawings. In view of the technical problems that the stability of the related technology mentioned in the above background technology is poor when working in a high temperature environment for a long time, it is difficult to realize the continuous temperature monitoring of the distribution, so that the temperature detection result is difficult to meet the needs of the refined operation management of the boiler, and the installation is cumbersome, the cost is high, etc., the present invention provides a temperature detection system for the heating surface of the boiler, in which a fiber grating sensor can be installed on the heating surface of the boiler by using a sensor fixing device, and the thermal optical effect and thermal expansion effect of the fiber grating sensor are used to realize the wall temperature detection of the heating surface of the boiler by collecting the central wavelength of the reflection spectrum reflected after the incident target light source, without the need for complex installation procedures, and the temperature detection result that meets the needs of the refined operation management of the boiler can be obtained, so as to ensure the safety of the boiler and improve the operation efficiency. Thus, the technical problems that the stability of the related technology is poor when working in a high temperature environment for a long time, it is difficult to realize the continuous temperature monitoring of the distribution, so that the temperature detection result is difficult to meet the needs of the refined operation management of the boiler, and the installation is cumbersome, the cost is high, etc. are solved.

[0028] Specifically, Figure 1 A schematic structural diagram of a temperature detection system for a boiler heating surface provided in an embodiment of the present invention.

[0029] like Figure 1 As shown, the temperature detection system 10 of the boiler heating surface includes: a fiber grating sensor 100, a sensor fixing device 200 and a temperature detection device 300.

[0030] Specifically, the sensor fixing device 200 is used to fix the fiber grating sensor 100 on the heating surface of the target boiler.

[0031] In the actual implementation process, the embodiment of the present invention can use the sensor fixing device 200 to fix the fiber Bragg grating sensor 100. Among them, the sensor fixing device 200 can bear the weight of the sensor and its connecting cable, and ensure that the sensor can remain stable after installation, and at the same time, it can also withstand the high temperature of the target boiler.

[0032] Optionally, in one embodiment of the present invention, a high-temperature thermal conductive silicone grease coating is provided on the installation contact surface of the fiber grating sensor 100 .

[0033] The fiber grating sensor 100 may be composed of a tubular structure of a fiber grating and an armored fiber grating, wherein the tubular structure used for armoring the fiber grating may be a stainless steel tube of a specific specification, wherein the specification of the tubular structure may be determined by the core size of the fiber grating. For example, the embodiment of the present invention may use a 304 stainless steel tube with an inner diameter of 1 mm to armor a fiber core with a diameter of 600 mm. m fiber Bragg grating. Among them, fiber Bragg grating is FBG (Fiber Bragg Grating); after broadband light enters the fiber Bragg grating FBG, most of the frequency band light directly passes through this area, and only a part of the frequency band light will be reflected back. This part of the reflected light has a specific wavelength, also known as the Bragg wavelength, which is expressed in It indicates that, by utilizing the characteristics of fiber Bragg grating, the embodiment of the present invention can detect the wall temperature of the boiler heating surface; By reasonably arranging gratings with different central wavelengths on the same channel, for example, by using wavelength division multiplexing technology, multiple fiber grating sensors with different central wavelengths are arranged in series on a single optical fiber. A fiber grating sensor is arranged every 50 cm along the direction of the water-cooled wall tubes on the heating surface of the boiler. The spacing distance can be set according to the specific conditions of the specific boiler. Each sensor is connected in series on the same armored optical fiber by fusion splicing, thereby realizing distributed temperature detection of the heating surface of the target boiler.

[0034] For another example, the embodiments of the present invention can also use a single multi-core optical fiber (7 cores or 19 cores) to integrate multiple grating arrays, each core is independently engraved with a periodic grating, the spacing between the gratings of each core is adjustable (minimum 5mm), and multi-dimensional signal demodulation is achieved through wavelength division multiplexing (WDM) and space division multiplexing (SDM) technology. Among them, a single optical fiber can achieve 7×N measurement points (7 cores×N gratings), the spatial resolution is improved to 5mm, and it can capture small temperature gradient changes; reduce the number of optical fiber layouts, reduce system complexity, and avoid signal crosstalk caused by multiple optical fiber entanglement.

[0035] In addition, during packaging, the embodiments of the present invention can also introduce a real-time compensation mechanism based on laser heat injection feedback, integrate a reference grating and a temperature measurement grating in parallel in the fiber Bragg grating sensor packaging layer, perform periodic thermal excitation on the reference grating through feedback laser, and use the Kalman filter algorithm to separate the temperature signal from the wavelength drift caused by mechanical stress / aging. This reduces the long-term temperature measurement error and maintains accuracy in variable operating conditions where the boiler is frequently started and stopped. This extends the life of the fiber Bragg grating sensor to more than 3 years.

[0036] In terms of packaging structure, for example, the embodiment of the present invention can also design a three-layer composite packaging structure: Inner layer: Aluminum nitride ceramic capillary (thermal conductivity ≥ 180 W / m·K) directly covers the grating; Middle layer: polyimide-graphene composite film (temperature resistant to 800°C) provides mechanical protection; Outer layer: Magnetic shape memory alloy (Fe-Ni-Ga) substrate, activated by a magnetic field to conform to the boiler surface.

[0037] Based on the above magnetic flexible packaging, the thermal response time can be shortened, and the instantaneous over-temperature signal before the boiler tube burst can be captured. The flexible packaging allows the sensor to fit the curved surface with a diameter of >20mm, and the installation strength is higher.

[0038] In addition to the above-mentioned magnetic flexible package, the embodiments of the present invention may also involve an anti-interference embedded package structure, such as a composite package using gradient thermal conductivity and electromagnetic shielding: Inner layer: High thermal conductivity silicon carbide fiber braided layer (thermal conductivity 200 W / m·K), quickly transmits temperature signals; Middle layer: Polyetheretherketone (PEEK) coating doped with metal nanoparticles to shield high-frequency electromagnetic interference in the boiler combustion chamber; Outer layer: Pre-loaded spring buckle structure enables the sensor to be adaptively fitted to the heated surface with micro-pressure (fitting force 0.5~2N adjustable).

[0039] Based on the above composite packaging, the thermal response time can be shortened and the instantaneous temperature change of the boiler under variable load conditions can be captured in real time; the electromagnetic interference suppression ratio is improved, which is suitable for high electromagnetic noise scenarios such as plasma ignition boilers.

[0040] Furthermore, before installing the fiber grating sensor 100, the embodiment of the present invention can apply high-temperature thermal grease to the contact portion between the fiber grating sensor 100 and the water-cooled wall of the boiler, that is, a high-temperature thermal grease coating is provided on the installation contact surface of the fiber grating sensor 100 to discharge air with poor thermal conductivity to adapt to temperature fluctuations caused by load changes in the furnace, wherein the thermal grease can be a high-temperature thermal grease with a thermal conductivity of 2.5 W / m·K.

[0041] Optionally, in one embodiment of the present invention, the sensor fixing device 200 is a pipe clamp structure consisting of an upper clamping plate and a lower clamping plate, and an elliptical opening is provided on the sensor fixing device 200 .

[0042] The structure of the sensor fixing device 200 can be a special pipe clamp, such as a standard double-bolt pipe clamp, which can be made of 304 stainless steel and has an elliptical opening on the side. The elliptical opening on the side of the pipe clamp can be used to prevent the pipe clamp from expanding due to changes in ambient temperature and avoid stress concentration during manufacturing and heating, ensuring that the pipe clamp is not easily deformed. The clamping structure of the pipe clamp can also be used to eliminate cross-effects to improve the accuracy of temperature detection results.

[0043] During installation, the fiber Bragg grating is a pressure-sensitive element, and a preload is applied during installation to eliminate zero drift. Therefore, the embodiment of the present invention can first obtain the preload that the fiber Bragg grating sensor 100 can withstand, wherein the preload can be provided by the manufacturer. Then, the fiber Bragg grating sensor 100 can be installed according to the preload using the sensor fixture 200. On this basis, the embodiment of the present invention can determine the initial calibration temperature under specific preload conditions, for example, at room temperature of 25°C, the initial center wavelength of the fiber Bragg grating sensor 100 is measured to be 1529nm, which serves as the basic data for subsequent measurement and calibration.

[0044] The grating area of ​​the fiber grating sensor 100 is not gold-plated to ensure its stability and thermal conductivity in a high temperature environment.

[0045] The temperature detection device 300 is used to guide the target light source to enter the fiber grating sensor 100, receive multiple sets of reflection spectrum center wavelengths after multiple incidents, and calculate the current wall temperature of the target boiler heating surface based on the multiple sets of reflection spectrum center wavelengths.

[0046] The temperature detection device 300 can be understood as a fiber Bragg grating demodulation system, including a target light source (such as a tunable light source), a fiber circulator and a spectrometer.

[0047] The temperature detection device 300 can achieve actual measurement and error control of the irregular wall temperature of the boiler heating surface by allowing a tunable light source to emit wide-band light, which reaches the grating through the optical fiber. The light at the center wavelength of the fiber grating is guided by the optical fiber circulator and reflected to the spectrometer. Finally, the center wavelengths of multiple reflection spectra are recorded and the average value is taken as the output signal.

[0048] The embodiment of the present invention can calculate the parameter value corresponding to the central wavelength of the reflected light based on the central wavelength of the reflected spectrum recorded by the spectrometer and the fiber grating sensing principle formula, substitute it into the formula considering the thermal effect to calculate the temperature change and add the initial calibration temperature to calculate the real-time temperature.

[0049] For example, the calculation process of the current wall temperature can be as follows: First, the embodiment of the present invention can obtain the central wavelength of the reflection spectrum from the spectrometer According to the coupled mode theory, the central wavelength of the reflection spectrum is It can be expressed as: , in, is the center wavelength of the reflection spectrum, is the effective refractive index of the optical fiber core, is the grating period, which is determined by the period of the interference fringes used for exposure during the manufacturing process; By differentiating the above formula, we can get: , in, It represents a finite change increment. According to mathematical principles and grating coupled mode theory, the reflection wavelength drift of the fiber grating can be calculated by changing the effective refractive index and grating period. , that is, the difference between the wavelength at the current temperature and the wavelength at the initial calibration temperature; Since the single-point stress can be considered unchanged by armored optical fiber and sensor deployment, the fiber Bragg grating parameter changes caused by thermal expansion effect and thermo-optical effect are expressed as: , , in, is the thermal expansion coefficient of the optical fiber, is the optical fiber thermo-optic coefficient. By substituting the above two equations into have to: , Then the temperature change is: , Calculate the temperature change Then add the preset initial calibration temperature, such as room temperature 25 , get the current wall temperature.

[0050] Optionally, in one embodiment of the present invention, the boiler heating surface temperature detection system 10 further includes: a calibration module.

[0051] The calibration module is used to calibrate the fiber grating sensor 100 before measuring the current wall temperature using the temperature detection device 300.

[0052] As a possible implementation method, the embodiment of the present invention can set a suitable temperature calibration range and step size, use a tubular heating furnace to continuously heat the fiber Bragg grating sensor 100, collect multiple sets of data after reaching each target temperature, and take the average value as the sensor signal at the corresponding temperature, thereby completing the calibration of the fiber Bragg grating sensor 100 and ensuring measurement accuracy.

[0053] Optionally, in one embodiment of the present invention, the calibration module includes: a heating unit, a sampling unit and a calibration unit.

[0054] The heating unit is used to heat the target boiler until the temperature of the fiber grating sensor 100 fixed on the heating surface of the target boiler reaches the target calibration range.

[0055] The sampling unit is used to perform multiple temperature measurements within a target calibration range based on a target step size to obtain multiple groups of sampling data.

[0056] The calibration unit is used to calibrate the fiber Bragg grating sensor 100 based on the multiple sets of sampling data, so as to obtain the current wall temperature using the calibrated fiber Bragg grating sensor 100.

[0057] For example, the embodiment of the present invention can set the calibration range to 25°C-720°C (including 25°C and 720°C) with a step size of 1°C, and use a heating unit, such as a tubular heating furnace, to continuously heat the fiber Bragg grating sensor 100. When the target temperature within the calibration range is reached, the temperature is maintained, and data sampling is performed using a sampling unit, with 50 sets of data collected each time; the calibration unit then takes an average of the 50 sets of data collected, and uses the average value as the signal of the current sensor at the temperature. In this way, sampling and calculation operations are performed at each target temperature point within the entire calibration range of 25°C-720°C, and calibration signals of the fiber Bragg grating sensor 100 at different temperatures are obtained. These calibration signals are used for subsequent temperature measurement and calibration.

[0058] Among them, the target calibration range can be obtained by the initial calibration temperature, such as room temperature, and the upper limit temperature of the boiler. For example, the lower limit temperature of the target calibration range can be room temperature, which is in line with the actual application scenarios and environmental conditions, and is convenient for the calculation and calibration of subsequent temperature changes; the upper limit temperature can be 720°C. Because some nickel-based boilers or boilers with new cooling systems can make the design temperature of the boiler water-cooled wall not exceed 650°C, considering the safety factor and possible temperature fluctuations in actual operation, the calibration upper limit can be set to 720°C to ensure the reliability and measurement accuracy of the sensor under extreme working conditions.

[0059] The step size can be 1°C, which can meet the needs of refined boiler operation management, especially in high temperature areas (>500°C). A smaller step size can improve the fitting accuracy of the calibration curve and ensure the accuracy of temperature measurement. Specifically, the target calibration range and step size can be set accordingly by those skilled in the art according to actual conditions, and no specific restrictions are made here.

[0060] Optionally, in one embodiment of the present invention, the boiler heating surface temperature detection system 10 further includes: a compensation grating sensor and a correction device.

[0061] Among them, a compensation grating sensor meets preset temperature and stress sensitivity characteristics.

[0062] The correction device is used to correct the current wall temperature based on the reflection wavelength data of the compensation grating sensor to obtain the actual wall temperature of the heating surface of the target boiler.

[0063] The embodiment of the present invention can also use a double grating compensation method to eliminate cross effects.

[0064] To this end, the embodiment of the present invention may also configure a fiber Bragg grating sensor having different characteristics from the fiber Bragg grating FBG, including a different grating period, a different core material or a different grating writing method, as a compensation grating sensor.

[0065] Based on the data obtained by the fiber grating sensor 100 and the compensation grating sensor when measuring temperature, the embodiment of the present invention can use the correction device to perform corresponding calculations to correct the current wall temperature and obtain a more accurate actual wall temperature.

[0066] For example, the compensation grating sensor of the embodiment of the present invention can be packaged in a coaxial silicon nitride ceramic sleeve (temperature resistant to 1200°C), which only senses environmental noise (such as vibration, electromagnetic interference), and is physically isolated from the fiber grating sensor 100 but in the same temperature field. It is suitable for scenarios where the vibration interference on the heating surface of the boiler is caused by the impact of medium flow; the independent packaging design of the compensation grating sensor can also avoid wavelength drift caused by high-temperature oxidation and extend its service life. In the subsequent use process, the differential calculation of the dual grating wavelength drift can be used to eliminate non-temperature related interference.

[0067] Optionally, in one embodiment of the present invention, the correction device includes: a first construction unit, a second construction unit, a calculation unit and a correction unit.

[0068] The first construction unit is used to construct a first relationship model between the first reflection wavelength drift of the fiber grating sensor 100 and the temperature change and stress change.

[0069] The second construction unit is used to construct a second relationship model between the second reflection wavelength drift of the compensation grating sensor and the temperature change and stress change.

[0070] The calculation unit is used to calculate the corrected reflection wavelength drift based on the actual reflection wavelength drift of the fiber grating sensor 100, the actual reflection wavelength drift of the compensation grating sensor, the first relationship model and the second relationship model.

[0071] The correction unit is used to correct the current temperature by using the correction reflection wavelength drift to obtain the actual temperature of the target boiler to be measured area.

[0072] In the actual implementation process, the first construction unit can establish the first reflection wavelength drift value of the fiber Bragg grating FBG, that is, the fiber Bragg grating sensor 100 through experimental testing. Temperature change and stress variation The first relational model of , in, and The temperature and stress sensitivity coefficients of the grating are measured in the fiber grating sensor 100. The temperature and stress sensitivity coefficients are determined by the material properties of the optical fiber and the manufacturing process of the grating. At the same time, the second construction unit can be tested experimentally to establish the second reflection wavelength drift of the compensation grating sensor. Temperature change and stress variation The second relational model: , in, and To compensate for the temperature and stress sensitivity coefficients of the grating sensor; The calculation unit can perform correction calculations. In actual measurement, the first reflection wavelength drift of the fiber grating sensor 100 is measured simultaneously. and compensate for the drift of the second reflection wavelength of the grating sensor ; According to the above two models, the stress variation is eliminated by solving the equations The reflection wavelength drift only related to the temperature change is obtained. ; Then the correction unit is based on Calculate temperature change , plus the initial calibration temperature to obtain the corrected accurate wall temperature.

[0073] In addition, the embodiment of the present invention can also perform wall temperature correction by constructing a temperature-stress-aging multi-parameter fusion compensation model.

[0074] Among them, in the temperature-stress-aging multi-parameter fusion compensation model, real-time stress separation: based on the vibration spectrum analysis of the reference grating, combined with the finite element model to invert the stress distribution of the boiler tube wall; aging factor iterative correction: through periodic self-checking of the grating reflection spectrum width change, the coating aging degree is quantified, and the compensation coefficient is dynamically updated; ambient temperature gradient compensation: auxiliary thermocouples are deployed in different areas of the boiler to calibrate the nonlinear error of the fiber Bragg grating temperature drift.

[0075] The embodiment of the present invention can obtain the actual wall temperature through the temperature-stress-aging multi-parameter fusion compensation model, so as to support manual calibration and reduce labor costs.

[0076] Combination Figure 2 and Figure 3 As shown, the working principle of the temperature detection system for the heating surface of a boiler according to an embodiment of the present invention is described in detail by taking an embodiment as an example.

[0077] Based on the above structure, the embodiment of the present invention realizes distributed temperature detection by rationally arranging gratings with different central wavelengths on the same channel, and eliminates cross-sensitivity items introduced by stress by designing the optical fiber armor and the temperature detection device 300, thereby realizing accurate measurement of the wall temperature.

[0078] Taking a boiler of a large enterprise as an example, the thermocouple sensor in the related technology has not been solved. In the previous temperature monitoring of the boiler, the problems such as poor stability, cumbersome wiring, and difficulty in achieving distributed continuous monitoring have been exposed. Figure 2 The embodiment of the present invention may include the following steps: Step S201: Preparation for installation of the fiber grating sensor 100 .

[0079] The embodiment of the present invention can prepare a 304 stainless steel tube with an inner diameter of 1 mm for armoring a core diameter of 600 mm. m FBG sensor; the special pipe clamp of the sensor fixing device 200 has the same structure as the standard double-bolt pipe clamp, is made of 304 stainless steel, has an elliptical opening on the side, and has a high-temperature thermal conductive silicone grease with a thermal conductivity of 2.5 W / m·K.

[0080] Install the sensor fixture 200: Fix the fiber Bragg grating sensor 100 with a special pipe clamp and tighten it with bolts. The elliptical opening on the side of the pipe clamp is used to avoid errors caused by the expansion of the pipe clamp due to changes in ambient temperature, and to prevent stress concentration during manufacturing and heating, so as to ensure that the pipe clamp is not easily deformed.

[0081] The installation method does not interfere with the operation of the water-cooled wall tubes, does not change the structure of the water-cooled wall tubes, is easy to install, and is conducive to the combing of optical fibers.

[0082] Apply thermal grease: Before installing the fiber grating sensor 100, apply high-temperature thermal grease to the contact portion of the fiber grating sensor 100 with the water-cooled wall to discharge air with poor thermal conductivity to adapt to temperature fluctuations caused by changes in the load in the furnace.

[0083] By using stainless steel pipes of specific specifications, special pipe clamps, and high-temperature thermal conductive silicone grease with specific thermal conductivity, this unique combination of sensor installation supporting materials provides a solid foundation for accurate measurement from the hardware level. The special design of the pipe clamp effectively eliminates the errors and stress concentration introduced by the expansion of the pipe clamp, and the high-temperature thermal conductive silicone grease can adapt to the complex temperature fluctuation environment in the furnace. These material properties together constitute a unique advantage that is different from other traditional measurement methods, and realize high-precision adaptation of wall temperature measurement under complex working conditions of the boiler heating surface.

[0084] Step S202: applying a preload force to the fiber grating sensor 100 and determining an initial wavelength.

[0085] According to the information provided by the manufacturer of the fiber Bragg grating sensor 100, a suitable preload force is applied to eliminate the zero drift. The center wavelength of the fiber Bragg grating sensor 100, 1529 nm, is selected as the initial wavelength under the conditions of room temperature 25°C, preload force applied, and no gold plating in the grating area.

[0086] When installing the fiber grating sensor 100, the pressure-sensitive characteristic of the fiber grating sensor 100 is utilized to apply a preload and determine the initial wavelength, which can provide basic data for subsequent precise measurements.

[0087] Step S203: Calibration experiment.

[0088] The embodiment of the present invention can set the calibration range to 25°C-720°C with a step size of 1°C, and use a tubular heating furnace to continuously heat the fiber Bragg grating sensor 100. When the target temperature within the calibration range is reached, the temperature is maintained and data sampling is performed, with 50 groups of data collected each time. The average value of the 50 groups of data collected is taken and used as the signal of the fiber Bragg grating sensor 100 at the temperature. In this way, sampling and calculation operations are performed at each target temperature point within the entire calibration range of 25°C-720°C, and calibration signals of the fiber Bragg grating sensor 100 at different temperatures are obtained. These calibration signals are used for subsequent temperature measurement and calibration.

[0089] Repeat the above process to complete the calibration of each temperature point within the entire calibration range.

[0090] The calibration experiment uses rigorous temperature range settings and step lengths, as well as multiple data acquisition and averaging methods to ensure the accuracy and reliability of the sensor signal.

[0091] Step S204: actual measurement.

[0092] The embodiment of the present invention can construct a demodulation system (temperature detection device 300) based on the fiber grating sensor 100, which includes a tunable light source, a fiber circulator and a spectrometer.

[0093] The tunable light source emits a wide-bandwidth light, which reaches the grating through the optical fiber. The light at the center wavelength of the fiber grating is guided by the fiber circulator, and the fiber circulator isolates the light path, so that the light at the center wavelength of the fiber grating is reflected to the spectrometer. The center wavelength of the multiple reflection spectra is recorded and the average value is taken as the output signal to realize the actual measurement and error control of the irregular wall temperature of the boiler heating surface.

[0094] Step S205: Temperature calculation and correction.

[0095] During normal operation of the boiler, the embodiment of the present invention can collect and average the central wavelength of the reflection spectrum once every 10 minutes.

[0096] The temperature calculation can be done as follows: Figure 3 As shown, the following steps are included: Step S1: Obtain the central wavelength of the reflection spectrum from the spectrometer According to the coupled mode theory, the central wavelength of the reflection spectrum is It can be expressed as: , in, is the effective refractive index of the optical fiber core, is the grating period, which is determined by the period of the interference fringes used for exposure during the manufacturing process.

[0097] Step S2: By differentiating the above formula, we can get: , in, It represents a finite change increment. According to mathematical principles and grating coupled mode theory, the reflection wavelength drift of the fiber grating can be calculated by changing the effective refractive index and grating period. , that is, the difference between the wavelength at the current temperature and the wavelength at the initial calibration temperature.

[0098] Step S3: Since the single-point stress can be considered unchanged by armoring the optical fiber and deploying sensors, the fiber Bragg grating parameter changes caused by thermal expansion effect and thermo-optical effect are expressed as: , , in, is the thermal expansion coefficient of the optical fiber, is the thermal-optical coefficient of the optical fiber.

[0099] Step S4: Substitute the above two equations into have to:

[0100] Step S5: Temperature change:

[0101] Step S6: Calculate the temperature change After that, add the initial calibration temperature room temperature 25 , get the current wall temperature.

[0102] After the calculation is completed, the cross-effect is eliminated.

[0103] The embodiment of the present invention can use a double grating compensation method to eliminate the cross-effect, and the specific process is as follows: A fiber Bragg grating sensor having different characteristics from the fiber Bragg grating FBG, including different grating period, different core material or different grating writing method, is used as a compensation grating, and a compensation grating sensor is constructed, wherein the sensitivity characteristics of the compensation grating to temperature and stress are different from those of the measurement grating.

[0104] Through experimental testing, the first reflection wavelength drift of the fiber Bragg grating sensor 100 is established. Temperature change and stress variation The first relational model: , in, and The temperature and stress sensitivity coefficients of the measurement grating of the fiber grating sensor 100 are determined by the material properties of the optical fiber and the manufacturing process of the grating.

[0105] At the same time, through experimental testing, the second reflection wavelength drift of the compensation grating sensor is established Temperature change and stress variation The second relational model: , in, and To compensate for the temperature and stress sensitivity coefficient of the grating.

[0106] Correction calculation, in actual measurement, simultaneously measure the reflection wavelength drift of the fiber grating sensor 100 and the compensation grating sensor and .

[0107] According to the above two models, the stress variation is eliminated by solving the equations The reflection wavelength drift only related to the temperature change is obtained. .

[0108] according to Calculate temperature change , plus the initial calibration temperature to obtain the corrected accurate wall temperature.

[0109] The embodiments of the present invention can establish an accurate relationship model between the reflection wavelength drift and the temperature and stress changes by introducing compensation gratings with different characteristics, and effectively eliminate stress interference by solving a set of equations, thereby obtaining the accurate wall temperature. This measurement and correction mechanism greatly improves the accuracy and scientificity of the boiler heating surface wall temperature measurement, and brings new breakthroughs and directions to boiler operation monitoring technology.

[0110] In summary, the embodiment of the present invention can achieve accurate measurement and error control of the irregular wall temperature of the boiler heating surface by using a fiber Bragg grating sensor 100 with a fiber Bragg grating FBG and a series of measurement methods such as installation preparation, preload force application, and calibration experiment, so as to more accurately grasp the temperature of the heating surface tube and ensure its normal working state. And through the correlation calculation between the wavelength and temperature of the fiber Bragg grating sensor 100 and the method of eliminating cross-effects such as double grating compensation, the temperature is measured and corrected to obtain the precise wall temperature of the boiler heating surface, which meets the high requirements of modern boiler refined operation management for temperature monitoring and overcomes the limitation that traditional thermocouple sensors are difficult to fully and accurately reflect the temperature field distribution.

[0111] According to the temperature detection system of the boiler heating surface proposed in the embodiment of the present invention, the fiber grating sensor can be installed on the boiler heating surface by using the sensor fixing device, and the thermal optical effect and thermal expansion effect of the fiber grating sensor can be used to detect the wall temperature of the boiler heating surface by collecting the central wavelength of the reflection spectrum reflected after the target light source is incident. There is no need for complicated installation procedures, and the temperature detection results that meet the needs of refined operation and management of the boiler can be obtained to ensure the safety of the boiler and improve the operation efficiency. Therefore, the technical problems in the related technology that the stability of long-term operation in a high temperature environment is poor, it is difficult to achieve continuous temperature monitoring, so that the temperature detection results are difficult to meet the needs of refined operation and management of the boiler, and the installation is cumbersome and the cost is high are solved.

[0112] Next, the temperature detection method of the heating surface of a boiler proposed in accordance with an embodiment of the present invention will be described with reference to the accompanying drawings.

[0113] Figure 4 It is a flow chart of a method for detecting the temperature of a boiler heating surface according to an embodiment of the present invention.

[0114] like Figure 4 As shown, the temperature detection method of the boiler heating surface uses the above-mentioned temperature detection system of the boiler heating surface, wherein the method comprises the following steps: In step S401, a target light source is guided to enter a fiber grating sensor.

[0115] In step S402, multiple groups of reflection spectrum center wavelengths after multiple incidents are received.

[0116] In step S403, the current wall temperature of the heating surface of the target boiler is calculated based on the multiple sets of reflection spectrum center wavelengths.

[0117] It should be noted that the above explanation of the embodiment of the temperature detection system for the heating surface of a boiler is also applicable to the temperature detection method for the heating surface of a boiler of this embodiment, and will not be repeated here.

[0118] According to the temperature detection method of the boiler heating surface proposed in the embodiment of the present invention, the fiber grating sensor can be installed on the boiler heating surface by using the sensor fixing device, and the thermal optical effect and thermal expansion effect of the fiber grating sensor can be used to detect the wall temperature of the boiler heating surface by collecting the central wavelength of the reflection spectrum reflected after the target light source is incident. There is no need for complicated installation procedures, and the temperature detection results that meet the needs of refined operation and management of the boiler can be obtained to ensure the safety of the boiler and improve the operation efficiency. Therefore, the technical problems in the related technology that the stability of long-term operation in a high temperature environment is poor, it is difficult to achieve continuous temperature monitoring, so that the temperature detection results are difficult to meet the needs of refined operation and management of the boiler, and the installation is cumbersome and the cost is high are solved.

[0119] Figure 5 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. The electronic device may include: A memory 501 , a processor 502 , and a computer program stored in the memory 501 and executable on the processor 502 .

[0120] When the processor 502 executes the program, the temperature detection method of the boiler heating surface provided in the above embodiment is implemented.

[0121] Furthermore, the electronic device further comprises: The communication interface 503 is used for communication between the memory 501 and the processor 502 .

[0122] The memory 501 is used to store computer programs that can be executed on the processor 502 .

[0123] The memory 501 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0124] If the memory 501, the processor 502 and the communication interface 503 are implemented independently, the communication interface 503, the memory 501 and the processor 502 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 5 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0125] Optionally, in a specific implementation, if the memory 501, the processor 502 and the communication interface 503 are integrated on a chip, the memory 501, the processor 502 and the communication interface 503 can communicate with each other through an internal interface.

[0126] The processor 502 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention.

[0127] This embodiment also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, the temperature detection method of the heating surface of the boiler as described above is implemented.

[0128] An embodiment of the present invention further provides a computer program product, including a computer program. When the computer program is executed by a processor, the method for detecting the temperature of a heating surface of a boiler provided in an embodiment of the present invention is implemented.

[0129] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0130] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0131] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0132] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or N wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways as necessary and then storing it in a computer memory.

[0133] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0134] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0135] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0136] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A temperature detection system for a boiler heating surface, characterized in that: include: Fiber Bragg Grating Sensors; A sensor fixing device, used for fixing the fiber grating sensor on the heating surface of the target boiler; A temperature detection device is used to guide a target light source to be incident on the fiber grating sensor, receive multiple groups of reflection spectrum center wavelengths after multiple incidents, calculate the current wall temperature of the target boiler heating surface based on the multiple groups of reflection spectrum center wavelengths, and construct a temperature-stress-aging multi-parameter fusion compensation model, so as to perform preset real-time stress separation, aging factor iterative correction and ambient temperature gradient compensation operations based on the temperature-stress-aging multi-parameter fusion compensation model, so as to obtain the boiler tube wall stress distribution corresponding to the target boiler, the aging factor correction parameter and the temperature gradient compensation parameter corresponding to the target boiler coating, and fuse the boiler tube wall stress distribution, the aging factor correction parameter and the temperature gradient compensation parameter to obtain the corresponding multi-parameter fusion compensation parameter, so as to use the multi-parameter fusion compensation parameter to correct the current wall temperature and obtain the current actual wall temperature of the target boiler heating surface.

2. The temperature detection system for the boiler heating surface according to claim 1, characterized in that: A high-temperature heat-conducting silicone grease coating is provided on the installation contact surface of the fiber grating sensor.

3. The temperature detection system for the boiler heating surface according to claim 1, characterized in that: The sensor fixing device is a pipe clamp structure composed of an upper clamping plate and a lower clamping plate, and an elliptical opening is arranged on the sensor fixing device.

4. The temperature detection system for the boiler heating surface according to claim 1, characterized in that: Also includes: The calibration module is used to calibrate the fiber grating sensor before using the temperature detection device to measure the current wall temperature.

5. The temperature detection system for the boiler heating surface according to claim 4, characterized in that: The calibration module comprises: A heating unit, used for heating the target boiler until the temperature of the fiber grating sensor fixed on the heating surface of the target boiler reaches a target calibration range; A sampling unit, used to perform multiple temperature measurements within the target calibration range based on a target step length to obtain multiple groups of sampling data; A calibration unit is used to calibrate the fiber grating sensor based on the multiple groups of sampling data, so as to obtain the current wall temperature using the calibrated fiber grating sensor.

6. The temperature detection system for the boiler heating surface according to claim 1, characterized in that: Also includes: Compensated grating sensors that meet preset temperature and stress sensitivity characteristics; A correction device is used to correct the current wall temperature based on the reflection wavelength data of the compensation grating sensor to obtain the actual wall temperature of the target boiler heating surface.

7. The temperature detection system for the boiler heating surface according to claim 6, characterized in that: The correction device comprises: A first construction unit is used to construct a first relationship model between the first reflection wavelength drift of the fiber Bragg grating sensor and the temperature change and stress change; A second construction unit is used to construct a second relationship model between the second reflection wavelength drift of the compensation grating sensor and the temperature change and stress change; a calculation unit, configured to calculate a corrected reflection wavelength drift amount based on an actual reflection wavelength drift amount of the fiber grating sensor, an actual reflection wavelength drift amount of the compensation grating sensor, the first relationship model, and the second relationship model; The correction unit is used to correct the current temperature using the corrected reflection wavelength drift to obtain the actual temperature of the target boiler's test area.

8. A method for detecting the temperature of a boiler heating surface, characterized in that: Using the temperature detection system for the heating surface of a boiler as claimed in any one of claims 1 to 7, wherein the method comprises the following steps: guiding a target light source to be incident on a fiber Bragg grating sensor; Receive multiple sets of reflected spectrum center wavelengths after multiple incidents; The current wall temperature of the heating surface of the target boiler is calculated based on the central wavelengths of the multiple groups of reflection spectra, and a temperature-stress-aging multi-parameter fusion compensation model is constructed, so as to perform preset real-time stress separation, aging factor iterative correction and ambient temperature gradient compensation operations based on the temperature-stress-aging multi-parameter fusion compensation model, so as to obtain the boiler tube wall stress distribution corresponding to the target boiler, the aging factor correction parameters and the temperature gradient compensation parameters corresponding to the target boiler coating, and fuse the boiler tube wall stress distribution, the aging factor correction parameters and the temperature gradient compensation parameters to obtain the corresponding multi-parameter fusion compensation parameters, so as to use the multi-parameter fusion compensation parameters to correct the current wall temperature and obtain the current actual wall temperature of the heating surface of the target boiler.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the temperature detection method for the heating surface of a boiler as claimed in claim 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the temperature detection method for the heating surface of a boiler as claimed in claim 8.

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