Vision-based cathode ray corona discharge performance judgment device and method

Abstract

The invention discloses a cathode ray corona discharge performance judgment device and method based on vision, the cathode ray corona discharge performance judgment device comprises a grating monochromator, a spherical mirror, a photomultiplier, a signal receiver and an image data processor, the grating monochromator splits corona discharge light, projects parallel light beams with different wavelengths to the spherical mirror at different diffraction angles, and outputs the parallel light beams with different wavelengths to the image data processor; the spherical mirror focuses the received parallel light beams at the slit to obtain a series of spectrums arranged according to the wavelength, the slit is provided with a photomultiplier, the photomultiplier emits electrons under light irradiation and impacts the anode to form an electric signal after the electrons are accelerated and amplified by the grid, and photoelectric conversion is realized. Therefore, better materials and structure types are brushed out, the energy consumption of the electric dust remover is reduced, the cathode wires which do not meet the installation requirements can be effectively found, accurate and rapid inspection and repair are achieved, the failed cathode wires can be rapidly recognized, and accurate and rapid maintenance and online monitoring are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas pollutant treatment and electrostatic precipitation, and particularly to a device and method for judging the corona discharge performance of a cathode wire based on vision. Background Art

[0002] Electrostatic precipitation is one of the mainstream technologies for dust removal in the flue gas field. Its basic principle is that corona discharge charges particulate matter, and dust is collected under the action of the electric field force. Therefore, strengthening electric field charging is very important for improving the performance of electrostatic precipitation.

[0003] Many documents have found that the corona discharge of electrostatic precipitators is not uniform, and the structures of the discharge electrode and the dust collecting electrode have a great influence on the electrostatic precipitation efficiency. A variety of discharge electrode structures have been proposed, including improvements in voltage, polarity, and structural form, etc. Hao Jiming et al. explored the simulation calculation method of the electrical parameters of the tubular barbed corona electrode of the electrostatic precipitator. Tsuchiya Yoshinaka et al. of Mitsubishi Heavy Industries, Japan, developed a new discharge electrode to make the current density distribution uniform, all of which have improved the electrostatic precipitation efficiency to a certain extent. There is an escape work for charges to break through the cathode surface, and the escape work has an important influence on the cathode discharge performance. WebneltA found that the escape work of the oxide cathode is very low and has the discharge characteristics of high current. Existing devices and methods cannot intuitively characterize the uniformity of corona discharge. In particular, there is no device that can intuitively detect the corona discharge intensity in all directions in space, so the corona discharge performance cannot be effectively optimized and improved.

[0004] CN202210872324.9 proposes to use oxide materials with high and low cathode escape work at the discharge end, which improves the discharge characteristics. However, the improvement of performance can only be measured by current measurement, and the degree of improvement in discharge performance cannot be directly shown, so the material screening efficiency is relatively low. 2018106004042 gives the measurement of the current uniformity of the anode plate of the electrostatic precipitator and the test of the spatial electric field strength, but the corona discharge intensity cannot be measured.

[0005] Existing devices and methods cannot intuitively characterize the uniformity of corona discharge. In particular, there is no device that can intuitively detect the corona discharge intensity in all directions in space, so the corona discharge performance cannot be effectively optimized and improved.

[0006] After the installation of the existing electrostatic precipitator, the number of cathode wires exceeds 50,000, and the number of thorn discharge points exceeds 4 million. It is impossible to efficiently inspect the installation quality, resulting in the inability to check the operating parameters of the electrostatic precipitator. Generally, an electrostatic precipitator is divided into 10 - 30 power supply zones. As long as the installation quality of one discharge point is poor, it will cause inefficiency or failure of one power supply zone. For example, generally in the design, the distance between the discharge point and the anode plate (pole pitch) is 190 ± 2 mm. The cathode wire is connected to the negative high voltage, and the anode plate is grounded. When the distance error between an individual discharge point and the anode plate exceeds 5 mm, this point will strongly discharge (on the side close to the anode plate), resulting in the high-voltage power supply being unable to raise the secondary voltage due to large local current, thus affecting the dust removal efficiency of the entire power supply zone.

[0007] When the electrostatic precipitator is in operation and during operation and maintenance, due to reasons such as thermal expansion and contraction and individual component failures, when the operating parameters of the high-voltage power supply are not good, due to the large number of cathode wires and anode plates, it is impossible to effectively carry out maintenance, and it is impossible to manually repair the fault points. Summary of the Invention

[0008] The purpose of the present invention is to solve the problems in the prior art and propose a device and method for judging the corona discharge performance of cathode wires based on vision, which can solve at least one of the above problems.

[0009] To achieve the above purpose, the present invention proposes a device for judging the corona discharge performance of cathode wires based on vision, including a grating monochromator, a spherical mirror, a photomultiplier tube, a signal receiver, and an image data processor. The grating monochromator disperses the light of the corona discharge, projects parallel light beams of different wavelengths onto the spherical mirror at different diffraction angles. The spherical mirror focuses the received parallel light beams at the exit slit to obtain a series of spectra arranged by wavelength. A photomultiplier tube is installed at the exit slit. The photomultiplier tube emits electrons under light irradiation and forms an electric signal after being accelerated and amplified by the grid and hitting the anode, realizing photoelectric conversion. The electric signal converted by the photomultiplier tube is transmitted to the image data processor through the signal receiver.

[0010] Preferably, the incident slit of the grating monochromator is on the same straight line as the central hole of the plate electrode, so that the light emitted during the corona discharge process passes through the hole and enters the slit, and the measured spectrum is a longitudinal spectrum.

[0011] Preferably, the peak wavelength of the spectrum passed by the grating monochromator is: 200.0 - 400.0 nm.

[0012] Preferably, the image data processor processes the corona discharge intensity data and picture data, controls the data acquisition and drawing, and forms a display of the discharge intensity photo on the image.

[0013] Preferably, the frequency of the corona discharge is 20-100 MHz.

[0014] As described above, for the usage method of a device for judging the performance of corona discharge of a cathode wire based on vision, in a dark environment, the corona discharge intensity is judged by the magnitude of the spectral peak at the characteristic wavelength within the range of 200.0-400.0 nm, which is positively correlated, and the specific quantitative relationship between the spectral peak and the discharge intensity is calibrated through experiments.

[0015] Advantages of the present invention: 1. Different materials and different structural types of the cathode wires of an electrostatic precipitator have a great influence on corona discharge. Changing the material and structural type can reduce the electron surface work function of the cathode wire and improve the thermionic emission ability. Under the same operating voltage, the current density of the electrostatic precipitator is larger, the dust charge is higher, and thus the energy consumption is lower; through the present invention, the corona discharge intensity can be effectively and quantitatively judged, so as to screen out better materials and structural types and reduce the energy consumption of the electrostatic precipitator; 2. There are a large number of cathode wires in an electrostatic precipitator. The number of cathode wires in one electrostatic precipitator can reach 30,000-50,000. After the electrostatic precipitator is installed, when the distance from the anode plate is too low due to reasons such as the installation or manufacturing quality of individual cathode wires, the operating voltage of the entire electric field cannot be raised, reducing the efficiency of the electrostatic precipitator. Due to the large number of cathode wires, the manual inspection workload is large and it is difficult to identify. Through the present invention, before the electrostatic precipitator is installed and put into operation, by performing no-load boosting and detecting through the present invention, the cathode wires that do not meet the requirements can be effectively found, realizing accurate and rapid inspection and repair; 3. There are a large number of cathode wires in an electrostatic precipitator. The number of cathode wires in one electrostatic precipitator can reach 30,000-50,000. After the electrostatic precipitator is installed, when the distance from the anode plate is too low due to reasons such as the installation or manufacturing quality of individual cathode wires, the operating voltage of the entire electric field cannot be raised, reducing the efficiency of the electrostatic precipitator. Due to the large number of cathode wires, the manual inspection workload is large and it is difficult to identify. Through the present invention, during the intermediate shutdown maintenance or on-line operation of the electrostatic precipitator, the failed cathode wires can be quickly identified, realizing accurate and rapid maintenance and on-line monitoring.

[0016] The features and advantages of the present invention will be described in detail through embodiments in conjunction with the drawings. Description of the Drawings

[0017] Figure 1 is the wavelength diagram of corona discharge; Figure 2 is the original ultraviolet photo of the spike wire of tungsten metal composite material; Figure 3 is the original ultraviolet photo of the spike wire of SPCC low-carbon steel material; Figure 4 is the visual recognition diagram of the ultraviolet photo of the spike wire of tungsten metal composite material; Figure 5 It is a visual recognition diagram of the ultraviolet photo of the barbed wire made of SPCC low-carbon steel material; Figure 6 It is a diagram of the photo shooting area; Figure 7 It is a plan view of the arrangement of the cathode wire and the anode plate. Specific implementation mode

[0018] A device for judging the corona discharge performance of a cathode wire based on vision according to the present invention includes a grating monochromator, a spherical mirror, a photomultiplier tube, a signal receiver and an image data processor. The grating monochromator disperses the light of the corona discharge, projects parallel light beams of different wavelengths onto the spherical mirror at different diffraction angles. The spherical mirror focuses the received parallel light beams at the exit slit to obtain a series of spectra arranged according to wavelengths. A photomultiplier tube is installed at the exit slit. The photomultiplier tube emits electrons under light irradiation and forms an electrical signal after being accelerated and amplified by the grid and hitting the anode, realizing photoelectric conversion. The electrical signal converted by the photomultiplier tube is transmitted to the image data processor through the signal receiver.

[0019] The incident slit of the grating monochromator is on the same straight line as the center hole of the plate electrode, so that the light emitted during the corona discharge passes through the hole and enters the slit, and the measured spectrum is a longitudinal spectrum.

[0020] The peak wavelength of the spectrum passed by the grating monochromator is: 200.0 - 400.0 nm.

[0021] Experiments show that the spectra of corona discharge mainly include 297.9, 316.8, 338.0, 367.8, 380.0 nm, etc., which belong to the ultraviolet spectrum. Experiments find that as the voltage increases, the spectral amplitude increases accordingly. There is a corresponding relationship between the spectral amplitude (light radiation intensity) and the discharge intensity. Therefore, the intensity of corona discharge can be judged according to the measured spectral amplitude.

[0022] The image data processor controls the data acquisition and drawing by processing the corona discharge intensity data and the picture data, and forms a display of the discharge intensity photo on the image.

[0023] The frequency of the corona discharge is 20 - 100 MHz.

[0024] The frequency range of corona discharge is related to factors such as the working voltage of the transmission line, the wire diameter and the environmental conditions. By analyzing the electromagnetic waves generated by corona discharge, the generation and development process of corona discharge can be understood, so as to carry out monitoring and control.

[0025] When corona discharge occurs in the electrostatic precipitator, the ionization region is mainly in the strong field range near the corona generation. There are ionization, excitation, recombination of particles and transitions from the excited state to the low energy state. Among them, the process of transition from the excited state to the low energy state will generate light radiation.

[0026] A method for using a device for judging the performance of corona discharge of a cathode wire based on vision. In a dark environment, the corona discharge intensity is judged by the magnitude of the spectral peak at the characteristic wavelength within the range of 200.0 - 400.0 nm, which is positively correlated. The specific quantitative relationship between the spectral peak and the discharge intensity is calibrated through experiments.

[0027] The dark environment is to avoid the interference of sunlight ultraviolet rays on the ultraviolet rays of corona discharge.

[0028] Embodiment 1: Under the working conditions of a secondary voltage of 50 kV, an RS spike wire and 480 anode plates, and a distance of 200 mm between the cathode wire and the anode plate, as Figure 7 shown, using a spike wire made of tungsten metal composite material, the discharge performance can be obtained through the device for judging the performance of corona discharge of the cathode wire based on vision as Figure 2 、 Figure 4 shown. Through quantitative data, the quantitative change of the discharge performance can be judged. After the bright spot ultraviolet rays in the figure are identified and converted, the maximum discharge point current intensity of the 4 discharge points representing one spike at the upper left corner is 3.33 μA.

[0029] Embodiment 2: Under the working conditions of a secondary voltage of 50 kV, an RS spike wire and 480 anode plates, and a distance of 200 mm between the cathode wire and the anode plate, as Figure 7 shown, using a spike wire made of SPCC low-carbon steel material, the discharge performance can be obtained through the device for judging the performance of corona discharge of the cathode wire based on vision as Figure 3 、 Figure 5 shown. Through quantitative data, the quantitative change of the discharge performance can be judged. After the bright spot ultraviolet rays in the figure are identified and converted, the maximum discharge point current intensity of the 4 discharge points representing one spike at the upper left corner is 2.53 μA.

[0030] The above embodiments are illustrative of the present invention, not restrictive of the present invention. Any scheme obtained by simply transforming the present invention belongs to the protection scope of the present invention.

Claims

1. A vision-based device for judging the performance of cathode wire corona discharge, characterized in that: It includes a grating monochromator, a spherical mirror, a photomultiplier tube, a signal receiver, and an image data processor. The grating monochromator disperses the light of corona discharge, projects parallel light beams of different wavelengths onto the spherical mirror at different diffraction angles. The spherical mirror focuses the received parallel light beams at the exit slit, obtaining a series of spectra arranged by wavelength. A photomultiplier tube is installed at the exit slit. The photomultiplier tube emits electrons under light irradiation, and after being accelerated and amplified by the grid, it impacts the anode to form an electrical signal, realizing photoelectric conversion. The electrical signal converted by the photomultiplier tube is transmitted to the image data processor through the signal receiver.

2. The visual-based cathode wire corona discharge performance judgment device according to claim 1, characterized in that: The incident slit of the grating monochromator is on the same straight line as the central hole of the plate electrode, so that the light emitted during the corona discharge process passes through the hole and enters the slit, and the measured spectrum is a longitudinal spectrum.

3. The visual-based cathode wire corona discharge performance judgment device according to claim 1, wherein: The peak wavelength of the spectrum passed by the grating monochromator is: 200.0 - 400.0 nm.

4. The visual-based cathode wire corona discharge performance judgment device according to claim 1, wherein: The image data processor controls the data acquisition and drawing by processing the corona discharge intensity data and picture data, and forms a display of the discharge intensity photo on the image.

5. The device for judging the corona discharge performance of a cathode ray based on vision according to claim 1, characterized in that: The frequency of corona discharge is 20 - 100 MHz.

6. The usage method of a visual-based cathode wire corona discharge performance judgment device according to any one of claims 1 to 5, characterized in that: In a dark environment, the corona discharge intensity is judged by the magnitude of the spectral peak at the characteristic wavelength within the range of 200.0 - 400.0 nm, showing a positive correlation. The specific quantitative relationship between the spectral peak and the discharge intensity is calibrated through experiments.

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