Thermal power plant boiler flame temperature measuring system and method

Abstract

The invention relates to the technical field of thermotechnical measurement, and discloses a thermal power plant boiler flame temperature measuring system and method.The thermal power plant boiler flame temperature measuring system comprises a sound wave emission module, a sound wave receiving module, a sound wave transmitting module and a sound wave receiving module, and the sound wave transmitting module is used for transmitting band-limited white noise generated after filtering of a band-pass filter into a thermal power plant boiler hearth through a loudspeaker; the sound signal is received by a microphone of the sound wave receiving module after passing through the flame in the hearth; the data acquisition module is used for collecting a transmitting signal of the sound wave transmitting module and a receiving signal of the sound wave receiving module, and processing and calculating the collected signals through a mutual turn-off function; the cooling device is used for protecting the sound wave guide pipe and key components of the measurement system through heat insulation and cooling measures, and it is ensured that the sound wave transmitting module, the sound wave receiving module and the data acquisition module conduct temperature measurement in a stable environment. According to the invention, through improving a signal processing algorithm and adjusting a measuring range, a single-path temperature measurement error is effectively reduced, and high-precision temperature measurement is ensured; the service life of the sensor can be obviously prolonged and the environmental adaptability of the system is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal measurement, and particularly to a system and method for measuring the temperature of a boiler flame in a thermal power plant. Background Art

[0002] As a key physical quantity for measuring the degree of hotness or coldness of an object or environment, temperature plays a crucial role in multiple fields, including daily life, agricultural breeding, industrial production, and medical and health care. Especially in flammable places such as computer rooms, granaries, and biomass warehouses, stable and effective temperature measurement means are required to prevent fires; in industries such as furnaces and metallurgy, accurate measurement of flame temperature is crucial for improving combustion efficiency and reducing pollutant emissions; while in environments such as vegetable greenhouses and hatchery production, it is necessary to maintain a stable temperature to promote the growth and development of crops and breeding objects. However, traditional temperature detection devices and technologies are relatively backward, usually relying on manual supervision or regular inspections, which not only consume a large amount of manpower and material resources, but also are difficult to meet the requirements of modern complex temperature measurement environments.

[0003] Contact temperature measurement methods such as thermocouples and high-temperature-resistant thermometers can provide relatively high temperature measurement accuracy, but they can only measure single-point temperature and are easily damaged in harsh environments, which are not suitable for long-term monitoring requirements. On the other hand, traditional non-contact temperature measurement methods such as radiation thermometry, although they do not need to directly contact the measured target and can provide high-precision measurement to a certain extent, are costly and easily interfered in dusty environments, and cannot effectively measure the internal temperature of the medium. With the progress of science and technology, acoustic thermometry, as a new non-contact temperature measurement technology, has attracted much attention due to its characteristics such as low cost, high temperature measurement accuracy, wide temperature measurement range, loose application environment, and good real-time performance. In particular, acoustic thermometry technology can also measure the internal temperature of the medium, which has significant advantages compared with traditional temperature measurement technologies.

[0004] However, current acoustic thermometry research mainly focuses on the tomographic imaging of two-dimensional temperature fields, and has not yet effectively solved the problem of low temperature resolution caused by insufficient single-path sampling rate, thus limiting the improvement of single-path temperature measurement accuracy. In addition, in the measurement of the temperature of a boiler flame in a thermal power plant, due to the importance of flue gas temperature to combustion economy and stability, accurate and reliable temperature measurement has become a key requirement in theoretical research and industrial applications. Although there are various temperature measurement methods, their applicability in high-temperature, strongly corrosive, and harsh flue gas environments still needs to be solved urgently. Therefore, it is particularly important to develop an efficient and accurate temperature measurement system and method suitable for complex working conditions. Summary of the Invention

[0005] In view of the above existing problems, the present invention is proposed.

[0006] Therefore, the present invention provides a system and method for measuring the flame temperature of a thermal power plant boiler to solve the problems of low temperature measurement accuracy in single-path acoustic temperature measurement in the prior art due to noise interference, signal attenuation, and algorithm limitations, the limitation that the traditional radiation temperature measurement method cannot measure the internal temperature of the medium in a dusty environment, and the problem that sensors are easily damaged or signal distortion occurs in harsh environments (high temperature, dusty, and fluctuating flue gas flow rate).

[0007] To solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides a system for measuring the flame temperature of a thermal power plant boiler, the system comprising an acoustic wave transmitting module, an acoustic wave receiving module, a data acquisition module, and a cooling device;

[0009] The acoustic wave transmitting module is used to transmit the band-limited white noise generated after being filtered by a band-pass filter into the furnace of the thermal power plant boiler through a loudspeaker, and the sound signal is received by the microphone of the acoustic wave receiving module after passing through the flame in the furnace;

[0010] The data acquisition module is used to collect the transmission signal of the acoustic wave transmitting module and the reception signal of the acoustic wave receiving module, and perform processing and calculation on the collected signals through a cross-correlation function;

[0011] The cooling device is used to protect the acoustic wave duct and the key components of the measurement system through heat insulation and cooling measures, ensuring that the acoustic wave transmitting module, the acoustic wave receiving module, and the data acquisition module perform temperature measurement in a stable environment.

[0012] As a preferred embodiment of the system for measuring the flame temperature of a thermal power plant boiler according to the present invention, wherein: the acoustic wave transmitting module is composed of a noise generator, a band-pass filter, a power amplifier, a loudspeaker, a range adjustment circuit, and a voltage follower;

[0013] The white noise signal generated by the noise generator is input into the band-pass filter for filtering to generate a band-limited white noise signal, and the band-limited white noise signal is amplified by the power amplifier;

[0014] The sound signal after passing through the power amplifier is divided into two paths. One path of the signal meets the voltage range requirements of the data acquisition card in the data acquisition module, and an additional dynamic range adjustment circuit will be added to automatically adjust the amplification factor according to the intensity of the signal received by the microphone, and then pass through the voltage follower and be sent to the data acquisition module for signal acquisition; the other path of the signal is transmitted into the furnace of the thermal power plant boiler through a loudspeaker.

[0015] As a preferred embodiment of the flame temperature measurement system for a thermal power plant boiler according to the present invention, the acoustic wave receiving module is composed of a microphone, an instrumentation amplifier, an amplification and filtering circuit, a range adjustment circuit, and a voltage follower;

[0016] The microphone receives the sound signal passing through the flame inside the furnace of the thermal power plant boiler, inputs the sound signal into the instrumentation amplifier for preliminary amplification processing, and then inputs it into the amplification and filtering circuit for further amplification and filtering;

[0017] The processed signal passes through the range adjustment circuit, automatically adjusts the amplification factor according to the signal intensity, and then reaches the data acquisition module through the voltage follower for signal acquisition.

[0018] As a preferred embodiment of the flame temperature measurement system for a thermal power plant boiler according to the present invention, a moving coil microphone is used as the sound signal receiving device.

[0019] As a preferred embodiment of the flame temperature measurement system for a thermal power plant boiler according to the present invention, the data acquisition module further includes:

[0020] The data acquisition module sends the collected data to the upper computer through the transmission port of the data acquisition card;

[0021] After the upper computer performs noise reduction and abnormal data rejection processing on the received signal, it calculates the acoustic wave propagation time using the cross-correlation algorithm, calculates the flame temperature according to the sound velocity-temperature model, and displays the temperature distribution as an intuitive image.

[0022] As a preferred embodiment of the flame temperature measurement system for a thermal power plant boiler according to the present invention, the calculation of the flame temperature includes:

[0023] The propagation speed of sound waves in flue gas depends on the temperature of the flue gas, and the formula is:

[0024]

[0025] Where C represents the propagation speed of sound in the medium, k represents the adiabatic index of the gas, R represents the gas constant, M represents the molecular weight of the gas, and T represents the gas temperature;

[0026] In practical applications, if the distance between the acoustic wave transmitting device and the receiving device is determined, the transit time of the acoustic wave between them can be measured, and the temperature relationship can be expressed as:

[0027]

[0028] Where D represents the distance between the transmitting device and the receiving device, B represents the sound constant, and τ represents the transit time of the acoustic wave.

[0029] As a preferred embodiment of the boiler flame temperature measurement system of the present invention, wherein: the cooling device includes:

[0030] The acoustic waveguide is embedded in the furnace wall and the outlet of the acoustic waveguide is on the inner side of the furnace wall;

[0031] The tail of the acoustic waveguide and the cooling chamber are fixed by a flange, and then the fixing plate at the tail of the acoustic waveguide is fixed to the outer wall of the furnace wall with expansion screws;

[0032] An asbestos gasket is placed on the flange between the cooling chamber and the acoustic waveguide for heat insulation, and the gap between the furnace wall and the acoustic waveguide is filled with refractory fiber or refractory cement insulation material.

[0033] In a second aspect, the present invention provides a method for measuring the flame temperature of a thermal power plant boiler, including:

[0034] An acoustic sensor array is arranged on the outer wall of the furnace of the thermal power plant boiler, and the acoustic sensor array collects the acoustic signals generated by the flame combustion;

[0035] After the acoustic signal is conditioned by a signal conditioning circuit, it is converted into a digital signal by a data acquisition card and transmitted to the upper computer. After the upper computer performs noise reduction and abnormal data rejection processing on the received signal, the cross-correlation algorithm is used to calculate the acoustic propagation time, and the flame temperature is calculated according to the sound speed-temperature model;

[0036] The temperature distribution is displayed as an intuitive image, and the operator evaluates and adjusts the combustion condition of the boiler according to the display result.

[0037] In a third aspect, the present invention provides an electronic device, including:

[0038] A memory and a processor;

[0039] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the method for measuring the flame temperature of the thermal power plant boiler are implemented.

[0040] In a fourth aspect, the present invention provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed by a processor, the steps of the method for measuring the flame temperature of the thermal power plant boiler are implemented.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a system and method for measuring the flame temperature of a thermal power plant boiler. By improving the signal processing algorithm and dynamic range adjustment, the single-path temperature measurement error is reduced to within 0.5%, significantly better than the 1.4% error of the traditional acoustic temperature measurement method, ensuring high-precision temperature measurement. In the system, the cooling device uses asbestos gaskets and refractory fibers for heat insulation, and combines with a positive pressure difference design, enabling the sensor to stably operate in a furnace with a temperature exceeding 1000°C, and the service life is extended by 3 times compared with traditional equipment, enhancing the environmental adaptability of the system. The cross-correlation algorithm based on Matlab supports millisecond-level temperature calculation and continuous monitoring, and at the same time, the hardware cost is only 1 / 5 of that of the radiation temperature measurement system, providing the advantages of real-time performance and low cost. In addition, by utilizing the ability of sound waves to penetrate the medium, the average temperature inside the flame is directly obtained, avoiding the limitation that the radiation method can only measure the surface temperature, and realizing the effective measurement of the temperature inside the flame. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0043] Figure 1 Schematic diagram of acoustic temperature measurement of the system according to the embodiment of the present invention;

[0044] Figure 2 Schematic diagram of the acoustic wave emission module of the system according to the embodiment of the present invention;

[0045] Figure 3 Schematic diagram of the acoustic wave receiving module of the system according to the embodiment of the present invention;

[0046] Figure 4 Schematic diagram of the moving coil microphone of the system according to the embodiment of the present invention;

[0047] Figure 5 Schematic diagram of the cooling device of the system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the following will make a detailed description of the specific embodiments of the present invention in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0049] Embodiment 1

[0050] Reference Figures 1 - 5 For an embodiment of the present invention, a system for measuring the flame temperature of a thermal power plant boiler is provided. As shown in Figure 1 the figure, it includes an acoustic wave emission module, an acoustic wave reception module, a data acquisition module, and a cooling device;

[0051] Specifically, the acoustic wave emission module is used to emit the band-limited white noise generated after being filtered by the band-pass filter into the furnace of the thermal power plant boiler through a loudspeaker. The sound signal is received by the microphone of the acoustic wave reception module after passing through the flame in the furnace;

[0052] Specifically, the data acquisition module is used to collect the emission signal of the acoustic wave emission module and the reception signal of the acoustic wave reception module, and perform processing and calculation on the collected signals through the cross-correlation function;

[0053] Specifically, the cooling device is used to protect the acoustic wave duct and the key components of the measurement system through heat insulation and cooling measures, ensuring that the acoustic wave emission module, the acoustic wave reception module, and the data acquisition module perform temperature measurement in a stable environment.

[0054] It should be noted that the present invention provides a system for measuring the flame temperature of a thermal power plant boiler. By improving the signal processing algorithm and dynamic range adjustment, the single-path temperature measurement error is reduced to less than 0.5%, significantly better than the 1.4% error of the traditional acoustic temperature measurement method, ensuring high-precision temperature measurement. In the system, the cooling device uses asbestos gaskets and refractory fiber heat insulation, combined with a positive pressure difference design, enabling the sensor to work stably in a furnace with a temperature exceeding 1000°C, and the service life is extended by 3 times compared with traditional equipment, enhancing the environmental adaptability of the system. The cross-correlation algorithm based on Matlab supports millisecond-level temperature calculation and continuous monitoring, and at the same time, the hardware cost is only 1 / 5 of that of the radiation temperature measurement system, providing the advantages of real-time performance and low cost. In addition, by utilizing the ability of acoustic waves to penetrate the medium, the average temperature inside the flame is directly obtained, avoiding the limitation that the radiation method can only measure the surface temperature, and realizing the effective measurement of the temperature inside the flame.

[0055] In the embodiment of the present application, the acoustic wave emission module is composed of a noise generator, a band-pass filter, a power amplifier, a loudspeaker, a range adjustment circuit, and a voltage follower;

[0056] Specifically, as shown in Figure 2The processing flow of the sound wave emission module shown is as follows: The white noise signal generated by the noise generator is input into the band-pass filter for filtering to generate a band-limited white noise signal, and the band-limited white noise signal is amplified by the power amplifier; The sound signal after passing through the power amplifier is divided into two paths. One path of the signal meets the voltage range requirements of the data acquisition card in the data acquisition module, and a dynamic range adjustment circuit will be added to automatically adjust the amplification factor according to the intensity of the signal received by the microphone, and then it is sent to the data acquisition module for signal acquisition through the emitter follower; The other path of the signal is emitted into the interior of the boiler furnace of the thermal power plant through the speaker.

[0057] It should be noted that the functions of the sound wave emission module in this embodiment include the generation, amplification, emission, etc. of sound wave signals. After being amplified by the power amplifier circuit, in order to meet the voltage range requirements of the data acquisition card, a dynamic range adjustment circuit will be added to automatically adjust the amplification factor according to the intensity of the signal received by the microphone, avoid signal oversaturation or insufficient amplitude, and ensure the stability of the time-of-flight (TOF) measurement.

[0058] In the embodiment of the present application, the sound wave receiving module is composed of a microphone, an instrumentation amplifier, an amplification and filtering circuit, a range adjustment circuit, and an emitter follower;

[0059] Specifically, as Figure 3 The processing flow of the sound wave receiving module shown is as follows: The sound signal passing through the flame inside the boiler furnace of the thermal power plant is received by the microphone, and the sound signal is input into the instrumentation amplifier for preliminary amplification processing and then input into the amplification and filtering circuit for further amplification and filtering; The processed signal passes through the range adjustment circuit to automatically adjust the amplification factor according to the signal intensity, and then it is sent to the data acquisition module for signal acquisition through the emitter follower.

[0060] It should be noted that for the design of the sound receiving device in the hardware part of the acoustic temperature measurement system, first, a microphone with higher sensitivity and excellent frequency response performance needs to be selected as the receiving sensor; second, since the sizes of different positions in the furnace are different, the signal energy received by the sound receiving system is also different. When the distance between the sound signal receiving / sending units is large, the received useful signal needs to be amplified to a sufficient amplitude, and when the distance is short, over-saturation must be avoided; third, due to the nature of the correlation function, the correlation function of single-wave signals of the same frequency is a single-wave signal of the same frequency, and the amplitude will not weaken. Therefore, when obtaining the time of flight (TOF) of sound waves, the correlation analysis method is adopted. Due to the existence of periodic signals, it will have a great impact on the measurement result and have a significant impact on the measurement accuracy, resulting in incorrect measurement results. Therefore, the periodic signals contained in the noise signal must be considered and removed as much as possible. Among them, AC sound is a common interference signal that needs to be removed; fourth, due to the existence of noise, there will also be high-frequency components in the output signal. To ensure and improve the measurement accuracy, various high-frequency components need to be removed.

[0061] Furthermore, a moving coil microphone is used as the sound signal receiving device;

[0062] It should be noted that a microphone is a receiving component for receiving sound signals and is widely used in many fields such as architectural acoustics and acoustic measurement. There are many classification methods for microphones. According to the energy conversion method, they can be divided into piezoelectric, capacitive, and electromagnetic types. For an electret microphone, the important factor in its sound-electricity conversion is the electric vibrating diaphragm, which is a very thin plastic diaphragm with a pure gold film evaporated on it. After passing through a high-voltage electric field electron tube, different polar charges exist on both sides. After the gold-plated side of the diaphragm faces outward through the metal shell, the other side of the diaphragm is separated from the metal plate through a thin insulating bushing, thus forming a capacitor between the metal film and the metal plate. When the electric vibrating plate encounters sound wave vibrations and the electric field at both ends of the capacitor changes, an alternating voltage exists. Moreover, its output impedance value is very high, greater than dozens of MΩ. The high impedance cannot be directly matched with the power amplifier chip, so a field-effect transistor needs to be connected to the microphone to transform the impedance. The characteristics of the field-effect transistor include a very high input impedance and a low noise coefficient, etc. However, the frequency response characteristics measured under close-range conditions are already very weak and it is difficult to meet the measurement effect requirements of the system. Therefore, this type of microphone requires a bias current to make it work, and it will be more troublesome to work in the actual production state. Therefore, this type of microphone cannot be used as the sound signal acquisition device in the temperature measurement system of this embodiment.

[0063] It should be noted that the diaphragm of a dynamic microphone is very light and thin, so it can vibrate along with the sound. The moving coil diaphragm will move along with the vibration of the diaphragm. The movable coil is suspended above the magnetic field. When the magnetic field moves, a small induced electromotive force will be generated. The intensity of the induced electromotive force is directly related to the vibration amplitude and frequency of the diaphragm. The electrical signal output by the movable coil is related to the received sound. Since the intensity of the signal corresponds to the frequency level, due to the function of the microphone, a dynamic microphone is used as the sound signal receiving device in the research of this embodiment, such as Figure 4 the schematic structural diagram of the dynamic microphone shown

[0064] In the embodiment of the present application, the data acquisition module further includes: the data acquisition module sends the collected data to the upper computer through the transmission port of the data acquisition card; after the upper computer performs noise reduction and abnormal data elimination processing on the received signal, it uses the cross-correlation algorithm to calculate the sound wave propagation time, calculates the flame temperature according to the sound speed-temperature model, and displays the temperature distribution in an intuitive image

[0065] Specifically, calculating the flame temperature includes:

[0066] The propagation speed of sound waves in flue gas depends on the temperature of the flue gas, and the formula is:

[0067]

[0068] where C represents the propagation speed of sound in the medium, k represents the adiabatic index of the gas, R represents the gas constant, M represents the gas molecular weight, and T represents the gas temperature

[0069] It should be noted that since the given mixed gas is constant is a constant, so the propagation speed of sound waves is controlled by the gas temperature. In practical applications, a sound wave transmitter and a sound wave receiver can be placed on both sides of the boiler. The transmitter emits a sound signal, which is detected and received by the receiver. Then, by emitting different frequency band signals multiple times on the same path and taking the average value, the influence of random errors is reduced, and finally the single-path temperature measurement error is less than 0.5%. The sound flight time (TOF) between the two is represented by τ. Since the distance D between the speaker and the microphone is already measured data, substituting C into the formula can solve the temperature between the speaker and the microphone

[0070] In practical applications, if the distance between the sound wave transmitting device and the receiving device is determined, the flight time of the sound wave between them can be measured, and the temperature relationship can be expressed as:

[0071]

[0072] Wherein, D represents the distance between the transmitting device and the receiving device, B represents the sound constant, and τ represents the acoustic wave transit time.

[0073] In the embodiments of the present application, as Figure 5 shown, the cooling device includes:

[0074] The acoustic waveguide is embedded in the furnace wall and the outlet of the acoustic waveguide is on the inner side of the furnace wall;

[0075] The tail of the acoustic waveguide and the cooling chamber are fixed by using a flange, and then the fixing plate at the tail of the acoustic waveguide is fixed to the outer wall of the furnace wall by using expansion screws;

[0076] An asbestos gasket is placed on the flange between the cooling chamber and the acoustic waveguide for heat insulation, and the gap between the furnace wall and the acoustic waveguide is filled with refractory fiber or refractory cement insulation material.

[0077] It should be noted that the combustion conditions in the boiler furnace of a thermal power plant are very harsh and the temperature is very high. In addition, due to the internal and external pressure differences, there will be a situation of flame impingement. At the same time, when the boiler is operating, a lot of smoke and dust will be generated, and the above situations will affect the temperature measurement. In extremely harsh cases, the measuring device will be damaged. Therefore, in order to actually apply the acoustic temperature measurement system, it is necessary to solve the problems of protecting the measuring instrument and on-site setting. Since the acoustic waveguide and the cooling chamber are welded, the setting of the acoustic waveguide is the setting of the cooling device.

[0078] It should be noted that the internal temperature of a boiler burning pulverized coal is very high, exceeding 1000 °C. Then the working process of the cooling device is as follows: The first sound chamber is connected to the inside of the boiler and requires heat convection; there is heat radiation inside and outside the second furnace, so this heat radiation will definitely affect the temperature in the sound chamber; the inside of the furnace wall is connected to the acoustic waveguide, so the heat generated by the furnace wall will diffuse outward. Generally speaking, the furnace wall is very thick, and the acoustic waveguide has a certain length, and the diameter of the tail of the acoustic waveguide is very narrow. However, there is a heat insulation device on the flange between the acoustic waveguides for relative heat insulation, so the heat of this part is very small and can be ignored. Because there is an air inlet in the cooling device, cold air will flow into the sound emission chamber. It is precisely because of the presence of cold air that the positive pressure difference between the inside of the furnace and the sound chamber is maintained. Generally, there is a slight negative pressure in the furnace, so it is not necessary to make the air flow in the emission chamber too large, so there will be no noise of strong air convection, which will cause deviation in the measurement result. This small positive pressure difference can prevent the influence of the convection generated by heat and cold on the temperature of the sound emission chamber. The heat shield between the two flanges between the sound chamber and the furnace can also prevent the influence of the furnace flame. In addition, in order to further protect the microphone, an additional insulating layer is added to the inside of the sound chamber 1.

[0079] In the embodiments of the present application, the existing measurement errors include:

[0080] (1) Influence of flue gas composition changes: The volume percentages of each flue gas component are important for the measurement results. Generally, the most basic components of flue gas are N 2 , O 2 , CO 2 , CO and H 2 O, etc., and the volume percentages of various gases are constantly changing. When the changes in flue gas composition are large, it has been experimentally observed that the results of acoustic flue gas temperature measurement will be affected, but the error generally does not exceed 1.4%.

[0081] (2) Influence of particulate matter: To analyze the influence of ash particle concentration on the calculation results, assuming that the ash particle concentrations of dry flue gas are 5000 mg / m 3 and 10000 mg / m 3 respectively, then the sound wave propagation speeds in them are 703.5 m / s and 703 m / s respectively, while the sound wave propagation speed without ash particles is 705 m / s. It can be seen that the influence of the change in ash particle concentration on the calculated temperature results does not exceed 0.4%.

[0082] (3) Influence of path distance: Since temperature and distance are in a square relationship, a 1% error in distance will cause a 2% error in temperature. Therefore, the accuracy of path distance measurement is crucial, especially for short-distance measurements with higher requirements.

[0083] (4) Influence of flue gas velocity: The flue gas velocity gradient in the measurement direction will affect the sound wave propagation speed. For example, if the flue gas temperature is 1000 °C and the sound wave propagation rate is 700 m / s, then a flue gas velocity of 1 m / s will cause a 0.3% error in the measured temperature. Theoretically, as long as the flue gas velocities in all directions in the path are measured, the error can be corrected.

[0084] This embodiment also provides a method for measuring the flame temperature of a thermal power plant boiler, including:

[0085] Arranging an acoustic sensor array on the outer wall of the furnace of the thermal power plant boiler to ensure that the acoustic signals generated by flame combustion can be comprehensively collected. After the system is started, the acoustic sensor array collects acoustic signals;

[0086] After the acoustic signals are conditioned by the signal conditioning circuit, they are converted into digital signals by the data acquisition card and transmitted to the upper computer. After the upper computer performs noise reduction and abnormal data rejection processing on the received signals, the cross-correlation algorithm is used to calculate the sound wave propagation time, and the flame temperature is calculated according to the sound speed-temperature model;

[0087] The temperature distribution is displayed in an intuitive image, and the operator evaluates and adjusts the boiler combustion condition according to the display results.

[0088] Exemplarily, if the measurement path of the acoustic temperature measurement device installed in a boiler is 6 m, the flue gas composition analysis is as follows:

[0089] N 2 : 82% (vol.); O 2 : 6% (vol.); CO 2 : 12% (vol.); H 2 O: 5% (wt)

[0090] If the measured time of flight of the acoustic wave pulse is 8.5 ms, then the average temperature on this path can be calculated. From the above flue gas composition analysis, we can get: k = 1.28, M = 29.24 g / mol. Combining with the flue gas constant R = 8314 kJ / kmol, the sound constant can be obtained: B = 364 m 2 / s2k;

[0091] The average temperature can be calculated from the equation: T = 1095.7 °C;

[0092] Therefore, from the above embodiments, it can be seen that the present invention realizes the single-path temperature measurement error reduced to less than 0.5% by improving the signal processing algorithm and dynamic range adjustment, which is significantly better than the 1.4% error of the traditional acoustic temperature measurement method, ensuring high-precision temperature measurement. In the system, the cooling device uses asbestos gaskets and refractory fiber insulation, and combines with the positive pressure difference design, enabling the sensor to work stably in a furnace with a temperature exceeding 1000 °C, and the service life is extended by 3 times compared with traditional equipment, enhancing the environmental adaptability of the system. The cross-correlation algorithm based on Matlab supports millisecond-level temperature calculation and continuous monitoring, and at the same time, the hardware cost is only 1 / 5 of that of the radiation temperature measurement system, providing the advantages of real-time performance and low cost. In addition, by utilizing the ability of sound waves to penetrate the medium, the average temperature inside the flame is directly obtained, avoiding the limitation that the radiation method can only measure the surface temperature, and realizing the effective measurement of the temperature inside the flame.

[0093] Embodiment 2

[0094] This embodiment provides an electronic device, which includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a carrier network, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a method for measuring the flame temperature of a thermal power plant boiler. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a button, a trackball, or a touchpad set on the computer device housing, or an external keyboard, a touchpad, or a mouse, etc.

[0095] This embodiment also provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by the processor, it implements the method proposed in the above embodiment.

[0096] The storage medium proposed in this embodiment and the method proposed in the above embodiment belong to the same inventive concept. For technical details not described in detail in this embodiment, reference can be made to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0097] Through the above description of the implementation manner, those skilled in the art can clearly understand that the present invention can be implemented by means of software and necessary general-purpose hardware. Of course, it can also be implemented by hardware, but in many cases, the former is a better implementation manner. Based on such an understanding, the technical solution of the present invention, in essence, or the part that makes a contribution to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a floppy disk, a read-only memory (ROM), a random access memory (RAM), a flash memory (FLASH), a hard disk, or an optical disc of a computer, etc., including several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the method of the embodiment of the present invention.

[0098] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

[0099] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present application can be implemented in various computer languages.

[0100] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0101] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device that implements the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0102] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0103] Although the preferred embodiments of the present application have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.

[0104] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A thermal power plant boiler flame temperature measurement system, characterized in that: The system includes an acoustic wave transmitting module, an acoustic wave receiving module, a data acquisition module and a cooling device; The sound wave transmitting module is used to transmit the band-limited white noise generated after filtering by the bandpass filter into the furnace of the thermal power plant boiler through the speaker, and the sound signal is received by the microphone of the sound wave receiving module after passing through the flame in the furnace; The data acquisition module is used to collect the transmission signal of the sound wave transmission module and the reception signal of the sound wave receiving module, and process and calculate the collected signals through a mutual shutoff function; The cooling device is used to protect the key components of the acoustic waveguide and the measuring system through heat insulation and cooling measures, ensuring that the acoustic wave transmitting module, the acoustic wave receiving module and the data acquisition module perform temperature measurement in a stable environment.

2. The thermal power plant boiler flame temperature measurement system according to claim 1, characterized in that: The acoustic wave transmitting module is composed of a noise generator, a bandpass filter, a power amplifier, a loudspeaker, a range adjustment circuit and a transmitter-follower; Inputting the white noise signal generated by the noise generator into the bandpass filter for filtering to generate a band-limited white noise signal, and amplifying the band-limited white noise signal through the power amplifier; The sound signal after passing through the power amplifier is divided into two paths. One signal is to meet the voltage range requirements of the data collection card in the data acquisition module. A dynamic range adjustment circuit will be added to automatically adjust the amplification factor according to the strength of the signal received by the microphone, and then it will be sent to the data acquisition module through the transmitter-follower device for signal collection; the other signal is transmitted into the furnace of the boiler of the thermal power plant through the speaker.

3. The thermal power plant boiler flame temperature measurement system according to claim 2, characterized in that: The sound wave receiving module is composed of a microphone, an instrument amplifier, an amplifying and filtering circuit, a range adjustment circuit and a transmitter-follower device; The microphone receives the sound signal passing through the flame inside the furnace of the thermal power plant boiler, inputs the sound signal into the instrument amplifier for preliminary amplification processing, and then inputs the sound signal into the amplification and filtering circuit for further amplification and filtering; The processed signal passes through the range adjustment circuit, automatically adjusts the amplification factor according to the signal strength, and then passes through the shooter follower to be sent to the data acquisition module for signal acquisition.

4. The thermal power plant boiler flame temperature measurement system according to claim 3, characterized in that: A dynamic microphone is used as a sound signal receiving device.

5. The thermal power plant boiler flame temperature measurement system according to claim 4, characterized in that: The data acquisition module also includes: The data acquisition module sends the collected data to the host computer through the transmission port of the data collection card; After the host computer performs noise reduction and abnormal data elimination processing on the received signal, it uses the cross-correlation algorithm to calculate the sound wave propagation time, calculates the flame temperature according to the sound speed-temperature model, and displays the temperature distribution in an intuitive image.

6. The thermal power plant boiler flame temperature measurement system according to claim 5, characterized in that: The calculation of flame temperature comprises: The propagation speed of sound waves in smoke depends on the temperature of the smoke, and the formula is: Among them, C represents the speed of sound propagation in the medium, k represents the adiabatic index of the gas, R represents the gas constant, M represents the gas molecular weight, and T represents the gas temperature; In practical applications, if the distance between the sound wave transmitter and the receiver is determined, the flight time of the sound wave between them can be measured, and the temperature relationship can be expressed as: Among them, D represents the distance between the transmitting device and the receiving device, B represents the sound constant, and τ represents the sound wave flight time.

7. The method for measuring the flame temperature of a thermal power plant boiler according to claim 6, characterized in that: The cooling device comprises: The acoustic waveguide is embedded in the furnace wall and the outlet of the acoustic waveguide is on the inner side of the furnace wall; Use flanges to fix the tail of the acoustic waveguide to the cooling chamber, and then use expansion screws to fix the fixing plate at the tail of the acoustic waveguide to the outer wall of the furnace wall; Asbestos pads are placed on the flange between the cooling chamber and the acoustic waveguide for heat insulation, and the gap between the furnace wall and the acoustic waveguide is filled with refractory fiber or refractory cement insulation materials.

8. A method for measuring the flame temperature of a boiler in a thermal power plant, characterized in that: include: Arrange an acoustic sensor array on the outer wall of the furnace of a thermal power plant boiler, wherein the acoustic sensor array collects acoustic wave signals generated by flame combustion; After the acoustic wave signal is conditioned by the signal conditioning circuit, it is converted into a digital signal by the data acquisition card and transmitted to the host computer. After the host computer performs noise reduction and abnormal data elimination on the received signal, it uses the cross-correlation algorithm to calculate the acoustic wave propagation time and calculates the flame temperature according to the sound speed-temperature model; The temperature distribution is displayed in an intuitive graphic format, and operators can evaluate and adjust the boiler combustion conditions based on the displayed results.

9. An electronic device, comprising a memory and a processor, characterized in that: The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the method according to claim 8 are implemented.

10. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that: When the computer executable instructions are executed by a processor, the steps of the method of claim 8 are implemented.

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