High-precision chlorine on-line detector

Abstract

The present application relates to chlorine detection technical field, and it relates to a kind of high-precision chlorine on-line detector.The present application is by first judging whether pipeline needs cleaning and the pipeline needing cleaning is cleaned, then the humidity of the chlorine sample gas to be detected is collected by pipeline heating temperature setting module, the humidity of the chlorine is set to heating gradient heating and dehumidification to reach the set chlorine allowable humidity.Meanwhile, the humidity of the sample gas after initial heating and dehumidification is rechecked, to ensure that the dehumidification reaches the set chlorine allowable humidity, and the gas that does not meet the requirements of recheck is urgently heated and dehumidified, to reduce the influence of chlorine loss caused by gas dissolved in water or condensation on chlorine concentration measurement.And in order to eliminate the deviation caused by the influence of ambient temperature and humidity on the light intensity attenuation degree in the process of optical detection, the light intensity attenuation degree is dynamically corrected by dynamic correction module to improve the accuracy of measurement and provide reliable data for subsequent safety control of chlorine.

Description

Technical Field

[0001] This invention relates to the field of chlorine detection technology, and specifically to a high-precision online chlorine detector. Background Technology

[0002] Chlorine gas, as an important raw material or byproduct in industrial production, poses a direct threat to human life and the surrounding environment should a leak occur. With increasing industrial automation and stricter environmental policies, the need for chlorine safety management is becoming more urgent. Online high-precision chlorine detection is crucial for ensuring industrial production safety, protecting the ecological environment, and safeguarding human health.

[0003] However, the existing technology has the following problems: 1. The existing technology uses a fixed heating temperature to heat and dehumidify the heat tracing pipeline. It does not set a heating temperature gradient for the segmented pipeline according to the initial humidity of the sample gas, nor does it re-measure the humidity after the initial heating to optimize the subsequent pipeline heating parameters. The fixed temperature may lead to incomplete dehumidification, which causes moisture to condense and adhere to the inner wall of the container and absorb chlorine gas from the sample gas, resulting in a decrease in sample concentration and affecting the accuracy of chlorine concentration detection.

[0004] 2. Existing technology only obtains the initial light intensity attenuation through laser light source and photodetector, without compensating for the light intensity attenuation by combining the real-time temperature and humidity in the sample cell. The laser absorption characteristics of chlorine molecules are significantly affected by the ambient temperature and humidity, which cannot match the true absorption characteristics of chlorine molecules, resulting in deviation in the light intensity attenuation analysis and miscalculation of chlorine concentration value. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing technologies and provide a high-precision online chlorine detector. By strictly controlling the temperature during the data acquisition process and using multiple dehumidification methods such as temperature increase and humidity re-detection to obtain dry and pure chlorine samples, and by dynamically correcting the optical detection results, the chlorine concentration can be monitored with high precision, effectively ensuring industrial production safety.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a high-precision online chlorine detector, including a sample gas acquisition module, a pipeline heating temperature setting module, a sample gas dehumidification treatment module, a pretreatment module, an optical detection module, and a dynamic correction module.

[0007] The connection relationships between the modules are as follows: the sample gas acquisition module is connected to the pipeline heating temperature setting module; the sample gas dehumidification module is connected to both the pipeline heating temperature setting module and the pretreatment module; and the optical detection module is connected to both the pretreatment module and the dynamic correction module.

[0008] The sample gas acquisition module determines whether the inner wall of the heated sampling pipeline needs cleaning. When cleaning is required, the heated sampling pipeline is cleaned, and after cleaning, chlorine sample gas is extracted at a constant speed using a corrosion-resistant diaphragm pump.

[0009] The pipeline heating temperature setting module collects the humidity of the chlorine sample gas, performs difference analysis between it and the set allowable humidity of chlorine, and determines the heating temperature gradient.

[0010] The sample gas dehumidification module re-collects the temperature and humidity of the chlorine sample gas after the initial heating treatment. If the re-collected humidity is greater than the set allowable humidity for chlorine, the heating temperature of the remaining pipeline area is set; otherwise, a constant temperature is maintained.

[0011] The pretreatment module maintains a constant temperature in the gas filtration area and performs impurity filtration on the dehumidified sample gas.

[0012] The optical detection module uses a laser light source with a specific wavelength that perfectly matches the absorption peak of chlorine molecules to emit a beam that passes through the sample cell, and the initial light intensity attenuation is obtained by a high-precision photodetector.

[0013] The dynamic correction module collects the gas temperature and humidity in the sample cell, obtains the corresponding light intensity attenuation correlation coefficient under the given temperature and humidity by querying the preset temperature and humidity-light intensity attenuation correlation coefficient table, performs dynamic compensation correction on the initial light intensity attenuation, obtains the corrected light intensity attenuation, and converts the corrected light intensity attenuation into an electrical signal to obtain the chlorine concentration value.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention compares the visual texture features, spectral intensity features and inner wall reflectivity features of the image with the corresponding standard features of the clean pipeline by real-time image acquisition of the heat tracing sampling pipeline, determines whether the pipeline needs to be cleaned, ensures that the collected chlorine sample gas is free from impurities, provides a pure sample gas basis for subsequent high-precision detection, and significantly reduces the detection deviation caused by sample gas contamination.

[0015] (2) The present invention performs a difference analysis between the initial humidity and the set allowable humidity of chlorine to determine the humidity deviation value. Based on the humidity deviation value, the heating temperature of each section of the pipeline is set to avoid energy waste caused by a single temperature, and to ensure that the sample gas is in a suitable detection state, so as to provide a stable environmental condition for high-precision concentration detection.

[0016] (3) After the initial heating treatment of the chlorine sample gas, the temperature and humidity of the chlorine sample gas are collected again. The heating temperature of the remaining pipeline area is set according to the temperature and humidity of the newly collected chlorine sample gas. This prevents the humidity from not meeting the standard due to uneven heating or insufficient local temperature during the initial heating and dehumidification. It also prevents the chlorine from being absorbed by the moisture and reducing its concentration, thereby ensuring the authenticity and reliability of the subsequent measurement data.

[0017] (4) The present invention obtains the corresponding light intensity attenuation correlation coefficient based on the gas temperature and humidity in the sample cell, performs dynamic compensation correction on the initial light intensity attenuation, and converts the corrected light intensity attenuation into an electrical signal to obtain the chlorine concentration value, thereby eliminating the interference of different temperature and humidity in the sample cell on the light intensity attenuation. The corrected detection data is more consistent with the actual chlorine concentration, significantly improving the detection accuracy. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the system module connections of the present invention.

[0020] Figure 2 This is a schematic diagram illustrating the specific process for determining the heating temperature in this invention.

[0021] Figure 3 This is a schematic diagram illustrating the specific process of the dynamic correction module in this invention. Detailed Implementation

[0022] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. Furthermore, it should be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale.

[0023] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification.

[0024] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0025] This invention first determines whether pipelines require cleaning and cleans those that do. Then, a pipeline heating temperature setting module collects the humidity of the chlorine sample gas to be tested. The chlorine is then dehumidified in stages using a set heating gradient to reach the set permissible humidity level. Simultaneously, the humidity of the sample gas after the initial dehumidification is rechecked to ensure that the dehumidification reaches the set permissible humidity level. Gases that do not meet the recheck requirements are subjected to emergency heating and dehumidification to reduce the impact of chlorine loss due to gas dissolution or condensation on chlorine concentration measurement. Furthermore, to eliminate the deviation in light intensity attenuation caused by ambient temperature and humidity during the optical detection process, a dynamic correction module dynamically corrects for light intensity attenuation, improving measurement accuracy and providing reliable data for subsequent safe management of chlorine.

[0026] Please see Figure 1 As shown, this invention provides a high-precision online chlorine detector. It includes a sample gas acquisition module, a pipeline heating temperature setting module, a sample gas dehumidification module, a pretreatment module, an optical detection module, and a dynamic correction module.

[0027] The connection relationships between the modules are as follows: the sample gas acquisition module is connected to the pipeline heating temperature setting module; the sample gas dehumidification module is connected to both the pipeline heating temperature setting module and the pretreatment module; and the optical detection module is connected to both the pretreatment module and the dynamic correction module.

[0028] The sample gas acquisition module determines whether the inner wall of the heated sampling pipeline needs cleaning. When cleaning is required, the heated sampling pipeline is cleaned, and after cleaning, chlorine sample gas is extracted at a constant speed using a corrosion-resistant diaphragm pump.

[0029] It should be noted that the method for determining whether the inner wall of the heat tracing sampling pipeline needs to be cleaned is as follows: a corrosion-resistant camera is used to acquire real-time images of the inside of the heat tracing sampling pipeline, the real-time acquired color images are dehazed and noise-reduced, and a spectrometer is used to acquire characteristic spectral maps of the inside of the heat tracing sampling pipeline.

[0030] Visual texture features are extracted from the color image after dehazing and noise reduction, and spectral intensity and reflectance features are extracted from the feature spectral map.

[0031] The color image and feature spectrum after defogging and noise reduction are compared with the original color image and feature spectrum of the clean pipeline. The visual texture features, spectral intensity features, and inner wall reflectivity features of the image are compared with the corresponding standard features of the clean pipeline to determine whether there are differences. If there are differences, the heat tracing sampling pipeline is determined to need cleaning; otherwise, the heat tracing sampling pipeline is determined not to need cleaning.

[0032] It should be noted that the method for determining whether there is a difference is as follows: The gray-level co-occurrence matrix algorithm is used to process the color image after dehazing and noise reduction to obtain the gray-level co-occurrence matrix. The key parameters of the image visual texture features are calculated through the gray-level co-occurrence matrix, including energy parameters, contrast parameters, and correlation parameters. The parameter difference between the acquired color image and the original color image is calculated. The calculated parameter difference is compared with the set difference judgment rules to determine whether there is a difference in the image visual texture features.

[0033] The calculation methods for energy parameters, contrast parameters, and correlation parameters are as follows: Determine the gray-level compression values ​​and pixel position relationships of the original image, where the pixel position relationships include the relative distance and angle between two pixels. Based on the original pixel matrix, extract adjacent pixel pairs according to the pixel position relationships, count the number of occurrences of each pixel pair, form a frequency matrix, normalize the frequency matrix to obtain the probability matrix, which is the gray-level co-occurrence matrix. Substitute the gray-level co-occurrence matrix into the existing standard calculation formulas for energy parameters, contrast parameters, and correlation parameters to obtain the energy parameters, contrast parameters, and correlation parameters, respectively.

[0034] In a specific instance, the difference judgment rule is as follows: when the difference in energy parameter, contrast parameter, or correlation parameter is greater than the set range of the corresponding parameter, it is determined that there is a difference in the visual texture features of the image; otherwise, it is determined that there is no difference in the visual texture features of the image. The set range can be ±2% of the standard energy parameter, standard contrast parameter, and standard correlation parameter.

[0035] The spectral intensity features of key bands are extracted from the real-time acquired feature spectrum. The standard spectral intensity features of the corresponding key bands are retrieved from the original feature spectrum of the clean pipeline. The difference between the spectral intensity features and the standard spectral intensity features is calculated. The difference is compared with the set difference threshold. If the difference exceeds the set difference threshold, it is determined that there is a difference in the spectral intensity features; otherwise, it is determined that there is no difference in the spectral intensity features. The key bands refer to the bands corresponding to the absorption of features such as chlorine reaction residue, dust adhesion, and chlorine crystallization.

[0036] The parameters for calculating the reflectivity characteristics of the inner wall are obtained through characteristic spectral maps. These parameters include the original light intensity count of the inner wall, the dark current light intensity count, and the original light intensity count of the standard plate. These counts are then substituted into the reflectivity calculation formula to obtain the reflectivity corresponding to the acquired characteristic spectral map. The reflectivity is compared with the standard reflectivity calculated from the original characteristic spectral map. If the reflectivity exceeds the set range of the standard reflectivity, a difference in the reflectivity characteristics of the inner wall is determined; otherwise, no difference is determined. The set range for the reflectivity is within ±5% of the standard reflectivity.

[0037] In one specific instance, the method for measuring the original light intensity count on the inner wall is as follows: the pipeline is kept with the same light source, distance, and spectrometer parameters as the standard plate; the count converted from the light signal received by the detector at this time is the original count on the inner wall.

[0038] The method for measuring dark current intensity counting is as follows: the light inlet of the spectrometer is completely blocked to ensure that no external light enters; at this time, the detector generates dark current only due to its own electron thermal motion, and the converted count is the dark current count.

[0039] The method for measuring the original count of the standard plate is as follows: Remove the pipeline, place a 99% reflective PTFE plate on the inner wall of the original pipeline, and ensure that the light source power, light source and detection distance, and spectrometer parameters are exactly the same as when measuring the pipeline. The detector receives the light signal at this time, and the converted count is the original count of the standard plate.

[0040] It should be noted that the formula for calculating reflectance is: ,in It's reflectivity. It is the original light intensity count of the inner wall. It is a dark current light intensity count. This is the original count of the standard board. It is the reflectivity of the standard plate.

[0041] This invention acquires real-time images of the heated sampling pipeline and compares the visual texture features, spectral intensity features, and inner wall reflectivity features of the images with the corresponding standard features of clean pipelines to determine whether the pipeline needs cleaning. This ensures that the collected chlorine sample gas is free of impurities, providing a pure sample gas basis for subsequent high-precision detection and significantly reducing detection deviations caused by sample gas contamination.

[0042] The pipeline heating temperature setting module collects the humidity of the chlorine sample gas, performs difference analysis between it and the set allowable humidity of chlorine, and determines the heating temperature gradient.

[0043] It should be added that the specific contents of the pipeline heating temperature setting module are as follows: an embedded corrosion-resistant mesh is installed at the gas inlet of the heat tracing sampling pipeline, and each intersection of the mesh is set as a sampling point. Humidity is collected at each sampling point, and the average humidity of each sampling point is calculated as the initial humidity of the sample gas. The difference between the initial humidity and the set allowable humidity of chlorine is analyzed to determine the humidity deviation value. The pipeline between the two humidity sampling devices in the heat tracing sampling pipeline is divided into sections of equal length, and a heating device is set in the middle of each section. The heating temperature of each section is set according to the humidity deviation value.

[0044] like Figure 2As shown, the heating temperature setting method for each section of the pipeline is as follows: S1, the humidity deviation value is divided equally according to the number of sections of the heat tracing sampling pipeline to obtain the target humidity at the end of each section of the pipeline.

[0045] In a specific example: the initial humidity of the sample gas is 60%RH, and the allowable humidity of chlorine is 45%RH. The pipeline between the two humidity acquisition devices is divided into three sections. The calculated humidity deviation value is 15%RH. The deviation value is divided by the number of sections of the heat tracing sampling pipeline to obtain an equal humidity of 5%RH. Therefore, the target humidity of the first section is the difference between the initial humidity and the equal humidity: 55%RH. The target humidity of the second section is the difference between the target humidity of the first section and the equal humidity: 50%RH. And so on. The target humidity of the third section is the allowable humidity of chlorine: 45%RH.

[0046] It should be added that the humidity target at the end of each pipeline section is obtained by calculation in order to determine the heating temperature of each section and set a temperature gradient that decreases segment by segment. This can reduce the uniformity of constant temperature and reduce resource waste.

[0047] S2. Extract the chlorine humidity and pipeline heating temperature correlation mapping table corresponding to the segment length from the chlorine humidity and pipeline heating temperature correlation mapping table based on the segment length of the pipeline.

[0048] It should be noted that the mapping table between chlorine humidity and pipeline heating temperature is established as follows: a large number of chlorine sample gas humidity heating experiments are set up, and the large number of chlorine sample gas humidity heating experiments are divided into heating experiments with different pipeline lengths.

[0049] Chlorine gas with different initial humidity was introduced into the heat tracing sampling pipelines corresponding to different pipeline lengths for heating experiments, and the chlorine gas introduction rate was the same in different heating experiments.

[0050] The heating sampling pipelines of the same pipeline length, which were filled with chlorine gas of different initial humidity, were heated at different heating temperatures, and the humidity of the chlorine gas sample after heating was measured.

[0051] The humidity of chlorine sample gas under different initial humidity and different heating temperatures in heating experiments with different pipeline lengths was statistically analyzed and integrated into a mapping table relating chlorine humidity to pipeline heating temperature.

[0052] S3. Input the initial humidity and target humidity of each pipeline section into the screened chlorine humidity and pipeline heating temperature correlation mapping table to determine the heating temperature of each pipeline section.

[0053] This invention performs a difference analysis between the initial humidity and the set allowable humidity for chlorine gas to determine the humidity deviation value. Based on the humidity deviation value, the heating temperature of each section of the pipeline is set to avoid energy waste caused by a single temperature, ensure that the sample gas is in a suitable detection state, and provide stable environmental conditions for high-precision concentration detection.

[0054] The sample gas dehumidification module re-collects the temperature and humidity of the chlorine sample gas after the initial heating treatment. If the re-collected humidity is greater than the set allowable humidity for chlorine, the heating temperature of the remaining pipeline area is set; otherwise, a constant temperature is maintained.

[0055] It should be noted that the heating temperature setting method for the remaining pipeline area is as follows:

[0056] Re-collect the temperature and humidity of the heated chlorine sample. Input the humidity of the chlorine sample, the set allowable humidity of chlorine, and the remaining pipeline length into the chlorine humidity and pipeline heating temperature correlation mapping table to output the heating temperature. Set the heating temperature of the remaining pipeline area to the output heating temperature.

[0057] It should be noted that the method for determining the setting value of maintaining a constant temperature is as follows: when the humidity of the re-collected chlorine sample is lower than the set allowable humidity of chlorine, the heating temperature of the remaining pipeline is maintained at the temperature of the re-collected chlorine sample based on the temperature of the re-collected and heated chlorine sample.

[0058] This invention re-collects the temperature and humidity of the chlorine sample gas after the initial heating treatment, and sets the heating temperature of the remaining pipeline area based on the re-collected temperature and humidity of the chlorine sample gas. This prevents the humidity from failing to meet the standard due to uneven heating or insufficient local temperature during the initial heating and dehumidification, and avoids the chlorine being absorbed by moisture and reducing its concentration, thereby ensuring the authenticity and reliability of subsequent measurement data.

[0059] The pretreatment module maintains a constant temperature in the gas filtration area and performs impurity filtration on the dehumidified sample gas.

[0060] It should be noted that a filtration assembly is installed in the gas filtration area. The filtration assembly adopts a two-stage filtration design: the first stage is a stainless steel corrosion-resistant metal mesh with a pore size of 5μm, used to intercept larger particulate impurities; the second stage is a polytetrafluoroethylene (PTFE) microporous membrane with a pore size of 0.22μm, used to filter out fine particles and oil. After the sample gas enters the pretreatment module from the dehumidification module, it first flows through the metal mesh, then through the PTFE microporous membrane, and finally outputs clean sample gas.

[0061] The gas filtration area of ​​this invention needs to maintain a constant temperature. The core purpose is to prevent the sample gas from condensing or changing its state due to temperature fluctuations during the filtration process, and to ensure that the humidity of the sample gas is consistent with the humidity output by the sample gas dehumidification module, so as to provide a stable environment for subsequent optical detection.

[0062] The optical detection module uses a laser light source with a specific wavelength that perfectly matches the absorption peak of chlorine molecules to emit a beam that passes through the sample cell and is received by a high-precision photodetector to obtain the initial light intensity attenuation.

[0063] This invention employs a laser light source with a specific wavelength that perfectly matches the absorption peak of chlorine molecules. The core principle is based on the molecular characteristic absorption principle: different gas molecules have unique absorption characteristics for light of specific wavelengths. Only when the laser wavelength perfectly matches the absorption peak of chlorine molecules can chlorine molecules absorb laser energy to the maximum extent, ensuring that the light intensity attenuation accurately reflects the chlorine concentration and avoiding interference from other gases or impurities on light absorption.

[0064] It should be noted that the characteristic absorption wavelength of the strongest absorption peak of chlorine is 330 nm.

[0065] The dynamic correction module collects the gas temperature and humidity in the sample cell, obtains the corresponding light intensity attenuation correlation coefficient under the given temperature and humidity by querying the preset temperature and humidity-light intensity attenuation correlation coefficient table, performs dynamic compensation correction on the initial light intensity attenuation, obtains the corrected light intensity attenuation, and converts the corrected light intensity attenuation into an electrical signal to obtain the chlorine concentration value.

[0066] like Figure 3 As shown, the main contents of the dynamic correction module are: W1, real-time acquisition of the temperature and humidity of the sample cell, and analysis of the difference between the temperature and humidity of the sample cell and the set allowable temperature and humidity range for chlorine gas to be unaffected by the environment, to obtain the temperature and humidity deviation value; wherein the standard temperature and humidity refers to the environment under which the light intensity attenuation will not be affected. Referring to the general technical requirements for optical gas detection instruments, the allowable temperature and humidity range for chlorine gas to be unaffected by the environment is specified as: temperature: 21℃-25℃, humidity: 40%RH-50%RH.

[0067] It should be noted that the specific implementation method of the difference analysis is as follows: when the temperature and humidity of the sample cell are higher than the maximum value of the set allowable temperature and humidity range for chlorine to be unaffected by the environment, the temperature and humidity deviation value is obtained by subtracting the temperature and humidity of the sample cell from the maximum value of the set allowable temperature and humidity range for chlorine to be unaffected by the environment; when the temperature and humidity of the sample cell are lower than the set allowable temperature and humidity range for chlorine to be unaffected by the environment, the temperature and humidity deviation value is obtained by subtracting the minimum value of the set allowable temperature and humidity range for chlorine to be unaffected by the environment from the temperature and humidity of the sample cell.

[0068] W2. Query the temperature and humidity-light intensity attenuation correlation coefficient table to obtain the light intensity attenuation correlation coefficient under the corresponding temperature and humidity deviation value. Calculate the corrected light intensity attenuation by multiplying the light intensity attenuation correlation coefficient by the initial light intensity attenuation.

[0069] It should be noted that the temperature and humidity-light intensity attenuation correlation coefficient table is constructed by setting up chlorine gas concentration test experiments in sample cells with different temperatures and humidity, introducing the same concentration of chlorine gas into the sample cells with different temperatures and humidity, and measuring the light intensity attenuation using an online chlorine gas detector.

[0070] The theoretical light intensity attenuation is determined based on the concentration of chlorine gas introduced using the Lambert-Beer law, and the ratio of the theoretical light intensity attenuation to the measured light intensity attenuation is used as the correlation coefficient for light intensity attenuation.

[0071] The correlation coefficients of light intensity attenuation in sample cells with different temperatures and humidity levels were statistically analyzed. The temperature and humidity deviation values ​​were calculated by calculating the difference between different temperatures and humidity levels and the allowable temperature and humidity ranges. The temperature and humidity deviation values ​​and the corresponding correlation coefficients of light intensity attenuation were integrated into a table of temperature and humidity-light intensity attenuation correlation coefficients.

[0072] W3. The corrected light intensity attenuation is converted into an electrical signal according to the Lambert-Beer law to obtain the chlorine concentration value.

[0073] It should be noted that during the electrical signal conversion process, the high-precision analog-to-digital converter built into the optical detection module first converts the analog optical signal corresponding to the corrected light intensity attenuation into a digital electrical signal, and then substitutes it into the above-mentioned modified Lambert-Beer law formula. ,in The concentration of chlorine gas in the sample. The optical path length of the sample cell. This is the corrected light intensity attenuation. The molar absorptivity of chlorine molecules for the specific wavelength laser used in this invention was determined through a calibration experiment. The chlorine concentration is calculated, converted to ppm, and then displayed.

[0074] This invention obtains the corresponding light intensity attenuation correlation coefficient based on the gas temperature and humidity in the sample cell, dynamically compensates and corrects the initial light intensity attenuation, and converts the corrected light intensity attenuation into an electrical signal to obtain the chlorine concentration value. This eliminates the interference of different sample cell temperatures and humidity on the light intensity attenuation, and the corrected detection data is closer to the actual chlorine concentration, significantly improving detection accuracy.

[0075] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0076] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0077] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0078] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0079] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0080] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-precision online chlorine detector, characterized in that, include: The sample gas acquisition module determines whether the inner wall of the heat-traced sampling pipeline needs to be cleaned. When cleaning is required, the heat-traced sampling pipeline is cleaned, and after cleaning, chlorine sample gas is extracted at a constant speed through a diaphragm pump. The pipeline heating temperature setting module collects the humidity of chlorine sample gas, performs difference analysis between it and the set allowable humidity of chlorine gas, and determines the heating temperature gradient. The specific contents of the pipeline heating temperature setting module are as follows: An embedded corrosion-resistant mesh is installed at the gas inlet of the heat tracing sampling pipeline. Each intersection of the mesh is set as a sampling point. Humidity is collected at each sampling point, and the average humidity at each sampling point is calculated as the initial humidity of the sample gas. The initial humidity was compared with the set allowable humidity for chlorine to determine the humidity deviation value. The pipeline between the two humidity acquisition devices in the heat tracing sampling pipeline is divided into sections of equal length. A heating device is installed in the middle of each section, and the heating temperature of each section is set according to the humidity deviation value. The heating temperature setting method for each section of the pipeline is as follows: The humidity deviation value is divided equally according to the number of segments of the heat tracing sampling pipeline to obtain the target humidity at the end of each segment; Based on the segment length of the pipeline, extract the corresponding chlorine humidity and pipeline heating temperature correlation mapping table from the chlorine humidity and pipeline heating temperature correlation mapping table. The initial humidity and target humidity of each pipeline section are input into the screened chlorine humidity and pipeline heating temperature correlation mapping table to determine the heating temperature of each pipeline section. The sample gas dehumidification module re-collects the temperature and humidity of the chlorine sample gas after the initial heating treatment. If the re-collected humidity is greater than the set allowable humidity for chlorine, the heating temperature of the remaining pipeline area is set; otherwise, a constant temperature is maintained. The pretreatment module maintains a constant temperature in the gas filtration area and performs impurity filtration on the dehumidified sample gas. The optical detection module uses a laser light source with a specific wavelength that perfectly matches the absorption peak of chlorine molecules to emit a beam that passes through the sample cell, and the initial light intensity attenuation is obtained by a high-precision photodetector. The dynamic correction module collects the gas temperature and humidity in the sample cell, determines the light intensity attenuation correlation coefficient under the given temperature and humidity according to the preset temperature and humidity-light intensity attenuation correlation coefficient table, performs dynamic compensation correction on the initial light intensity attenuation, obtains the corrected light intensity attenuation, and converts the corrected light intensity attenuation into an electrical signal to obtain the chlorine concentration value.

2. The high-precision online chlorine detector according to claim 1, characterized in that: The method for determining whether the inner wall of the heat tracing sampling pipeline needs cleaning is as follows: A corrosion-resistant camera is used to acquire real-time images of the heat tracing sampling pipeline. The real-time acquired color images are then dehazed and noise-reduced. At the same time, a spectrometer is used to acquire characteristic spectral maps of the heat tracing sampling pipeline. Visual texture features are extracted from the color image after dehazing and noise reduction, and spectral intensity and reflectance features are extracted from the feature spectral map. The color image and feature spectrum after defogging and noise reduction are compared with the original color image and feature spectrum of the clean pipeline. The visual texture features, spectral intensity features, and inner wall reflectivity features of the image are compared with the corresponding standard features of the clean pipeline to determine whether there are differences. If there are differences, the heat tracing sampling pipeline is determined to need cleaning; otherwise, the heat tracing sampling pipeline is determined not to need cleaning.

3. The high-precision online chlorine detector according to claim 2, characterized in that: The method for determining whether a difference exists is as follows: The gray-level co-occurrence matrix algorithm is used to process the dehazing and noise reduction color image to obtain the gray-level co-occurrence matrix. The key parameters of the image visual texture features are calculated through the gray-level co-occurrence matrix, including energy parameters, contrast parameters, and correlation parameters. The parameter difference between the acquired color image and the original color image is calculated. The calculated parameter difference is compared with the set difference judgment rules to determine whether there is a difference in the image visual texture features. Extract the spectral intensity features of key bands from the real-time acquired feature spectrum map, retrieve the standard spectral intensity features of the corresponding key bands from the original feature spectrum map of the clean pipeline, calculate the difference between the spectral intensity features and the standard spectral intensity features, compare the difference with the set difference threshold, and if the difference exceeds the set difference threshold, it is determined that there is a difference in the spectral intensity features; otherwise, it is determined that there is no difference in the spectral intensity features. The parameters for calculating the reflectivity characteristics of the inner wall are obtained by using the characteristic spectral map. These parameters include the original light intensity count of the inner wall, the dark current light intensity count, and the original light intensity count of the standard plate. The original light intensity count, dark current light intensity count, and original light intensity count of the standard plate are substituted into the reflectivity calculation formula to obtain the reflectivity corresponding to the acquired characteristic spectral map. The reflectivity is compared with the standard reflectivity calculated from the original characteristic spectral map. If the reflectivity exceeds the range set by the standard reflectivity, it is determined that there is a difference in the reflectivity characteristics of the inner wall; otherwise, it is determined that there is no difference in the reflectivity characteristics of the inner wall.

4. The high-precision online chlorine detector according to claim 1, characterized in that: The mapping table relating chlorine humidity to pipeline heating temperature is established as follows: A large-scale chlorine gas sample humidity heating experiment was set up, and the large-scale chlorine gas sample humidity heating experiment was divided into heating experiments with different pipeline lengths. Chlorine gas with different initial humidity was introduced into the heat tracing sampling pipelines corresponding to heating experiments of different pipeline lengths, and the chlorine gas introduction rate was the same in different heating experiments. The heating sampling pipelines with different initial humidity of chlorine gas were heated at different heating temperatures in the heating experiment of the same pipeline length, and the humidity of the chlorine gas sample after heating was measured. The humidity of chlorine sample gas under different initial humidity and different heating temperatures in heating experiments with different pipeline lengths was statistically analyzed and integrated into a mapping table relating chlorine humidity to pipeline heating temperature.

5. A high-precision online chlorine detector according to claim 4, characterized in that: The method for setting the heating temperature of the remaining pipeline area is as follows: Re-collect the temperature and humidity of the heated chlorine sample. Input the humidity of the chlorine sample, the set allowable humidity of chlorine, and the remaining pipeline length into the chlorine humidity and pipeline heating temperature correlation mapping table to output the heating temperature. Set the heating temperature of the remaining pipeline area to the output heating temperature.

6. The high-precision online chlorine detector according to claim 5, characterized in that: The method for determining the setting value for maintaining a constant temperature is as follows: When the humidity of the re-collected chlorine sample is lower than the set allowable humidity for chlorine, the heating temperature of the remaining pipeline area is maintained at the temperature of the re-collected chlorine sample, based on the temperature of the re-collected and heated chlorine sample.

7. The high-precision online chlorine detector according to claim 1, characterized in that: The main contents of the dynamic correction module are: The temperature and humidity of the sample cell are collected in real time. The difference between the temperature and humidity of the sample cell and the set allowable temperature and humidity range for chlorine gas that is not affected by the environment is analyzed to obtain the temperature and humidity deviation value. The light intensity attenuation correlation coefficient is obtained by consulting the temperature and humidity-light intensity attenuation correlation coefficient table for the corresponding temperature and humidity deviation value. The corrected light intensity attenuation is calculated by multiplying the light intensity attenuation correlation coefficient with the initial light intensity attenuation. The corrected light intensity attenuation was converted into an electrical signal according to the Lambert-Beer law to obtain the chlorine concentration value.

8. A high-precision online chlorine detector according to claim 7, characterized in that: The table of correlation coefficients between temperature / humidity and light intensity attenuation is constructed as follows: An experiment was set up to test the chlorine gas concentration in sample cells with different temperatures and humidity. The same concentration of chlorine gas was introduced into the sample cells with different temperatures and humidity, and the light intensity attenuation was measured by an online chlorine gas detector. The theoretical light intensity attenuation is determined by the Lambert-Beer law based on the concentration of chlorine gas introduced, and the ratio of the theoretical light intensity attenuation to the measured light intensity attenuation is used as the correlation coefficient of light intensity attenuation. The correlation coefficients of light intensity attenuation in sample cells with different temperatures and humidity levels were statistically analyzed. The temperature and humidity deviation values ​​were calculated by calculating the difference between different temperatures and humidity levels and the allowable temperature and humidity ranges. The temperature and humidity deviation values ​​and the corresponding correlation coefficients of light intensity attenuation were integrated into a table of temperature and humidity-light intensity attenuation correlation coefficients.

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