High-precision chlorine online detector

Abstract

The invention relates to the technical field of chlorine gas detection, and relates to a high-precision chlorine gas online detector. Whether the pipeline needs to be cleaned or not is judged firstly, the pipeline needing to be cleaned is cleaned, then the humidity of the chlorine gas sample to be detected is collected through the pipeline heating temperature setting module, and the chlorine gas is subjected to segmented heating gradient heating dehumidification to reach the set chlorine gas allowable humidity. Meanwhile, the humidity of the sample gas subjected to primary heating and dehumidification is rechecked, it is ensured that dehumidification reaches the set chlorine allowable humidity, the gas which does not meet the requirement after rechecking is subjected to emergency heating and dehumidification, and the influence on chlorine concentration measurement caused by chlorine damage due to the fact that the gas is dissolved in water or condensed is reduced. And in order to eliminate the deviation of the light intensity attenuation degree caused by the influence of the environment temperature and humidity in the optical detection process, the light intensity attenuation degree is dynamically corrected through a dynamic correction module, so that the measurement accuracy is improved, and reliable data is provided for the subsequent safety management and control of chlorine.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of chlorine detection, and relates to a high-precision chlorine on-line detector. BACKGROUND

[0002] Chlorine is an important production raw material or by-product in the industrial field, and once leakage occurs, the safety of personnel life and the surrounding environment will be directly threatened. With the improvement of industrial automation level and the increasingly strict environmental protection policy, the safety control demand of chlorine is more urgent. How to detect high-precision chlorine on-line is of great significance for guaranteeing the safety of industrial production, protecting the ecological environment and maintaining the health of personnel life.

[0003] However, the prior art has the following problems: 1. The prior art uses fixed heating temperature to heat and dehumidify the heat tracing pipeline, does not set the heating temperature gradient of the segmented pipeline according to the initial humidity of the sample gas, and does not retest the humidity after initial heating to optimize the subsequent pipeline heating parameters. The fixed temperature may cause incomplete dehumidification, resulting in condensation and adhesion of water in the container wall to absorb the sample gas chlorine, causing the sample concentration to decrease and affecting the accuracy of chlorine concentration detection.

[0004] 2. The prior art only obtains the initial light intensity attenuation degree through a laser light source and a photoelectric detector, does not compensate and correct the light intensity attenuation degree in combination with the real-time temperature and humidity in the sample cell, and the laser absorption characteristics of chlorine molecules are significantly affected by the environmental temperature and humidity. It cannot match the real absorption characteristics of chlorine molecules, resulting in analysis deviation of the light intensity attenuation degree and causing the chlorine concentration value to be calculated incorrectly. SUMMARY

[0005] The application aims to overcome the deficiencies of the prior art and provide a high-precision chlorine on-line detector. By strictly controlling the temperature during the collection process, using temperature elevation, humidity retesting and other dehumidification methods to obtain dry and pure chlorine samples, and dynamically correcting the optical detection results, the chlorine concentration is monitored with high precision, and the safety of industrial production is effectively guaranteed.

[0006] The technical solution adopted by the application to solve the technical problems is: a high-precision chlorine on-line detector, comprising a sample gas collection module, a pipeline heating temperature setting module, a sample gas dehumidification processing module, a pretreatment module, an optical detection module and a dynamic correction module.

[0007] The connection relationship between the modules is: the sample gas collection module is connected with the pipeline heating temperature setting module, the sample gas dehumidification processing module is connected with the pipeline heating temperature setting module and the pretreatment module, and the optical detection module is connected with the pretreatment module and the dynamic correction module.

[0008] The sample gas collecting module judges whether the inner wall of the heat tracing sampling pipeline needs to be cleaned, and when the cleaning is needed, the heat tracing sampling pipeline is cleaned, and after the cleaning, the chlorine sample gas is extracted at a constant speed by the corrosion-resistant diaphragm pump.

[0009] The pipeline heating temperature setting module collects the humidity of the chlorine sample gas, and carries out difference analysis on the set allowed humidity of the chlorine gas to determine the heating temperature gradient.

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

[0011] The preprocessing module maintains a constant temperature in the gas filtering area, and carries out impurity filtering operation on the sample gas after the dehumidification treatment.

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

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

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

[0015] (2) The present application carries out difference analysis on the initial humidity and the set allowed humidity of the chlorine gas to determine the humidity deviation value, sets the heating temperature of each section of the pipeline according to the humidity deviation value, avoids energy waste caused by a single temperature, ensures that the sample gas is in a suitable detection state, and provides stable environmental conditions for high-precision concentration detection.

[0016] (3) The present application re-collects the temperature and humidity of the chlorine sample gas after the initial heating treatment of the chlorine sample gas, sets the heating temperature of the remaining pipeline area according to the re-collected temperature and humidity of the chlorine sample gas, prevents the humidity from not meeting the standard due to uneven heating, local temperature deficiency and other reasons after the initial heating and dehumidification, avoids the reduction of chlorine concentration caused by water absorption, and further ensures the authenticity and reliability of the subsequent measurement data.

[0017] (4) The application obtains the corresponding light intensity attenuation correlation coefficient according to the gas temperature and humidity in the sample cell, dynamically compensates and corrects the initial light intensity attenuation degree, converts the corrected light intensity attenuation degree into the chlorine concentration value through the electric signal, eliminates the interference of different sample cell temperature and humidity on the light intensity attenuation degree, and the corrected detection data is closer to the actual chlorine concentration, so that the detection precision is significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0019] Figure 1 It is a schematic diagram of system module connection of the application.

[0020] Figure 2 It is a specific flowchart of heating temperature determination in the application.

[0021] Figure 3 It is a specific way flowchart of dynamic correction module in the application. DETAILED DESCRIPTION

[0022] Various exemplary embodiments of the present application will now be described in detail below with reference to the accompanying drawings. Note that the relative arrangement, numerical expressions, and values of the components and steps set forth in these embodiments are not limiting to the scope of the present application unless otherwise specifically stated. Also, it should be understood that the sizes of the various parts shown in the drawings are not drawn to scale for the convenience of description.

[0023] The following description of at least one example embodiment is merely illustrative in nature and is in no way limiting to the scope of the application and its applications or uses. Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered part of the specification where appropriate.

[0024] In all examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not as limiting. Thus, other examples of the example embodiments can have different values.

[0025] The application first judges whether the pipeline needs to be cleaned, and then cleans the pipeline that needs to be cleaned, and then collects the humidity of the chlorine sample gas to be detected through the pipeline heating temperature setting module, and sets the heating gradient of the chlorine gas in sections to heat and dehumidify to reach the set allowable humidity of the chlorine gas. At the same time, the humidity of the sample gas after the initial heating and dehumidification is rechecked to ensure that the dehumidification reaches the set allowable humidity of the chlorine gas, and the gas that does not meet the requirements of the recheck is urgently heated and dehumidified to reduce the influence of the chlorine gas loss caused by the gas dissolved in water or condensation on the chlorine gas concentration measurement. And in order to eliminate the deviation of the light intensity attenuation degree in the optical detection process caused by the influence of the environment temperature and humidity, the light intensity attenuation degree is dynamically corrected through the dynamic correction module to improve the measurement accuracy and provide reliable data for the subsequent safety control of the chlorine gas.

[0026] Referring to Figure 1 As shown in the drawings, the application provides a high-precision chlorine online detector. The high-precision chlorine online detector comprises a sample gas collection module, a pipeline heating temperature setting module, a sample gas dehumidification processing module, a pretreatment module, an optical detection module and a dynamic correction module.

[0027] The connection relationship between the modules is that the sample gas collection module is connected with the pipeline heating temperature setting module, the sample gas dehumidification processing module is connected with the pipeline heating temperature setting module and the pretreatment module respectively, and the optical detection module is connected with the pretreatment module and the dynamic correction module respectively.

[0028] The sample gas collection module judges whether the inner wall of the heat tracing sampling pipeline needs to be cleaned, and when cleaning is needed, the heat tracing sampling pipeline is cleaned, and after cleaning, the chlorine sample gas is extracted at a constant speed by the corrosion-resistant diaphragm pump.

[0029] It should be noted that the method for judging whether the inner wall of the heat tracing sampling pipeline needs to be cleaned is as follows: a corrosion-resistant camera is used to collect real-time images inside the heat tracing sampling pipeline, the color images collected in real time are subjected to fog removal and noise reduction processing, and a spectrometer is used to collect characteristic spectrum images inside the heat tracing sampling pipeline.

[0030] The image visual texture features are extracted from the color images subjected to fog removal and noise reduction processing, and the spectral intensity features and reflectivity features are extracted from the characteristic spectrum images.

[0031] The color images subjected to fog removal and noise reduction processing and the characteristic spectrum images are compared with the original color images and the characteristic spectrum images of the clean pipeline respectively, the image visual texture features, the spectral intensity features and the inner wall reflectivity features are compared with the corresponding standard features of the clean pipeline, whether there is a difference is judged, if there is a difference, it is determined that the heat tracing sampling pipeline needs to be cleaned, otherwise it is determined that the heat tracing sampling pipeline does not need to be cleaned.

[0032] It should be noted that the method of determining whether there is a difference is as follows: the gray level co-occurrence matrix algorithm is used to process the color image after the de-fogging and de-noising processing to obtain a gray level co-occurrence matrix, the key parameters of the image visual texture features are calculated through the gray level co-occurrence matrix, the key parameters include energy parameters, contrast parameters and correlation parameters, the parameter difference values of the collected color image and the original color image are calculated, the calculated parameter difference values are compared with the set difference judgment rules, and whether the image visual texture features have differences is determined.

[0033] The calculation methods of the energy parameters, the contrast parameters and the correlation parameters are as follows: the original image gray level compression value and the pixel position relationship are determined, the pixel position relationship includes the relative distance and the angle between two pixels, the adjacent pixel pairs are extracted according to the pixel position relationship according to the original pixel matrix, the number of occurrences of each pixel pair is counted, the frequency matrix is formed, the probability matrix is obtained by normalizing the frequency matrix, that is, the gray level co-occurrence matrix, and the energy parameters, the contrast parameters and the correlation parameters are obtained by respectively bringing the gray level co-occurrence matrix into the existing standard calculation formulas of the energy parameters, the contrast parameters and the correlation parameters.

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

[0035] The spectral intensity features of the key bands are extracted from the real-time collected characteristic spectrum image, the standard spectral intensity features of the corresponding key bands in the clean pipeline original characteristic spectrum image are called, the difference value between the spectral intensity features and the standard spectral intensity features is calculated, the difference value is compared with the set difference threshold value, when the difference value exceeds the set difference threshold value, it is determined that the spectral intensity features have differences, otherwise it is determined that the spectral intensity features have no differences; wherein the key bands refer to the bands corresponding to the characteristic absorptions of chlorine gas reaction residues, dust adhesion and chlorine gas crystallization.

[0036] The parameters for calculating the inner wall reflectivity features are obtained through the characteristic spectrum image, wherein the parameters include the original light intensity count of the inner wall, the dark current light intensity count and the standard plate original light intensity count, the original light intensity count, the dark current light intensity count and the standard plate original light intensity count are brought into the reflectivity calculation formula to obtain the reflectivity corresponding to the collected characteristic spectrum image, the reflectivity is compared with the standard reflectivity calculated from the original characteristic spectrum image, if the reflectivity exceeds the set range of the standard reflectivity, it is determined that the inner wall reflectivity features have differences, otherwise it is determined that the inner wall reflectivity features have no differences. The set range of the reflectivity is between the standard reflectivity ± 5%.

[0037] In a specific example, the measurement method of the inner wall original light intensity count is: keeping the pipeline to be measured with the same light source, distance, and spectrometer parameters as the standard plate; converting the light signal received by the detector at this time into count, which is the inner wall original count.

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

[0039] The measurement method of the standard plate original count is: removing the pipeline, placing a 99% reflectivity polytetrafluoroethylene plate on the inner wall of the original pipeline, keeping the light source power, light source and detection distance, and spectrometer parameters consistent with the pipeline measurement; converting the light signal received by the detector at this time into count, which is the standard plate original count.

[0040] It should be noted that the reflectivity calculation formula is: , wherein is the reflectivity, is the inner wall original light intensity count, is the dark current light intensity count, is the standard plate original count, is the reflectivity of the standard plate.

[0041] The present application compares the image visual texture features, spectral intensity features, and inner wall reflectivity features of the heat tracing sampling pipeline with the corresponding standard features of the clean pipeline to determine whether the pipeline needs to be cleaned, ensures that the collected chlorine sample gas is not interfered by impurities, provides a pure sample gas basis for subsequent high-precision detection, and significantly reduces the detection deviation caused by sample gas pollution.

[0042] The pipeline heating temperature setting module collects the humidity of the chlorine sample gas and performs difference analysis on the set chlorine allowable humidity to determine the heating temperature gradient.

[0043] It should be noted that the specific content of the pipeline heating temperature setting module is as follows: a corrosion-resistant grid is installed at the gas inlet of the heat tracing sampling pipeline, each intersection of the grid is set as a collection point, the humidity of each collection point is collected, and the average humidity of each collection point is calculated as the initial humidity of the sample gas; difference analysis is performed on the initial humidity and the set chlorine allowable humidity to determine the humidity deviation value; the pipeline between the two humidity collection devices in the heat tracing sampling pipeline is divided into sections according to equal length, heating devices are arranged in the middle of each section of pipeline, and the heating temperature of each section of pipeline is set according to the humidity deviation value.

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

[0045] In a specific example: the initial humidity of the sample gas is 60% RH, the allowable humidity of chlorine is 45% RH, the pipeline between the two humidity collection devices is divided into three segments, the humidity deviation value is 15% RH, the equally divided humidity is 5% RH by dividing the deviation value by the number of segments of the heat tracing sampling pipeline, so the target humidity of the first segment is the difference between the initial humidity and the equally divided humidity: 55% RH, the target humidity of the second segment is the difference between the target humidity of the first segment and the equally divided humidity: 50% RH, and so on, and the target humidity of the third segment is the allowable humidity of chlorine: 45% RH.

[0046] It needs to be pointed out that the humidity target at the end of each segment of the pipeline is obtained by calculation to determine the heating temperature of each segment to set a temperature gradient that decreases step by step, which can reduce the temperature singleness of constant temperature and reduce resource waste.

[0047] S2, the chlorine humidity and pipeline heating temperature correlation mapping table corresponding to the segment length is extracted from the chlorine humidity and pipeline heating temperature correlation mapping table according to the segment length of the pipeline.

[0048] It needs to be pointed out that the chlorine humidity and pipeline heating temperature correlation mapping table is established as follows: a large number of chlorine sample gas humidity heating experiments are set, and the large number of chlorine sample gas humidity heating experiments are divided into heating experiments of different pipeline lengths.

[0049] Different initial humidities of chlorine are introduced into the heat tracing sampling pipeline corresponding to the heating experiment of different pipeline lengths, and the chlorine introduction speed is the same in different heating experiments.

[0050] The heat tracing sampling pipeline with different initial humidity of chlorine introduced into the heating experiment of the same pipeline length is heated at different heating temperatures, and the humidity of the heated chlorine sample gas is measured.

[0051] The chlorine sample gas humidity of different initial humidities at different heating temperatures in the heating experiment of different pipeline lengths is counted and integrated into the chlorine humidity and pipeline heating temperature correlation mapping table.

[0052] S3, the initial humidity and target humidity of each segment of the pipeline are brought into the screened chlorine humidity and pipeline heating temperature correlation mapping table to determine the heating temperature of each segment of the pipeline.

[0053] The initial humidity and the set allowable humidity of chlorine are analyzed by difference to determine the humidity deviation value, the heating temperature of each segment of the pipeline is set according to the humidity deviation value, the energy waste caused by single temperature is avoided, the sample gas is ensured to be in a suitable detection state, and a stable environmental condition is provided 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: 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.

[0056] 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.

[0057] This invention involves re-collecting the temperature and humidity of the chlorine sample gas after the initial heating treatment. The heating temperature of the remaining pipeline area is then set 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 process, and avoids the chlorine being absorbed by moisture and reducing its concentration. This ensures the authenticity and reliability of subsequent measurement data.

[0058] The pretreatment module maintains a constant temperature in the gas filtration area and performs impurity filtration on the dehumidified sample gas.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] The application adopts a specific wavelength laser light source that is completely matched with the absorption peak of chlorine molecules, and is based on the principle of molecular characteristic absorption: different gas molecules have exclusive absorption characteristics for specific wavelengths of light. Only when the wavelength of the laser light is completely matched with the absorption peak of chlorine molecules, can the chlorine molecules absorb the laser energy to the greatest extent, ensuring that the light intensity attenuation degree can accurately reflect the chlorine concentration, and avoiding the interference of other gases or impurities on light absorption.

[0063] It should be noted that the characteristic absorption wavelength of the strongest absorption peak of chlorine is 330 nm.

[0064] The dynamic correction module collects the temperature and humidity of the gas in the sample cell, obtains the corresponding light intensity attenuation correlation coefficient under the temperature and humidity by querying the preset temperature and humidity-light intensity attenuation correlation coefficient table, dynamically compensates and corrects the initial light intensity attenuation degree, obtains the corrected light intensity attenuation degree, and converts the corrected light intensity attenuation degree into an electrical signal to obtain the chlorine concentration value.

[0065] As shown in Figure 3 The main content of the dynamic correction module is: W1, real-time collection of the temperature and humidity of the sample cell, difference analysis of the temperature and humidity of the sample cell and the set allowed temperature and humidity range of chlorine not affected by the environment to obtain the temperature and humidity deviation value; wherein the standard temperature and humidity refers to the temperature and humidity under which the light intensity attenuation degree is not affected, and according to the general technical requirements of optical gas detection instruments, the allowed temperature and humidity range of chlorine not affected by the environment is: temperature: 21-25℃, humidity: 40%-50%RH.

[0066] It should be noted that the specific implementation of difference analysis is: when the temperature and humidity of the sample cell is higher than the maximum value of the set allowed temperature and humidity range of chlorine not affected by the environment, the temperature and humidity deviation value is obtained by subtracting the maximum value of the set allowed temperature and humidity range of chlorine not affected by the environment from the temperature and humidity of the sample cell; when the temperature and humidity of the sample cell is lower than the set allowed temperature and humidity range of chlorine not affected by the environment, the temperature and humidity deviation value is obtained by subtracting the minimum value of the set allowed temperature and humidity range of chlorine not affected by the environment from the temperature and humidity of the sample cell.

[0067] W2, query the temperature and humidity-light intensity attenuation correlation coefficient table to obtain the light intensity attenuation correlation coefficient corresponding to the temperature and humidity deviation value, and calculate the corrected light intensity attenuation degree by multiplying the light intensity attenuation correlation coefficient by the initial light intensity attenuation degree.

[0068] It should be noted that the temperature and humidity-light intensity attenuation correlation coefficient table is constructed by: setting chlorine gas concentration test experiments for sample cells with different temperature and humidity, and passing chlorine gas with the same concentration into sample cells with different temperature and humidity, and measuring the light intensity attenuation degree by the chlorine online detector.

[0069] The theoretical light intensity attenuation degree is determined according to the concentration of the chlorine gas introduced by the Lambert-Beer law, and the ratio of the theoretical light intensity attenuation degree to the measured light intensity attenuation degree is used as the light intensity attenuation correlation coefficient.

[0070] The light intensity attenuation correlation coefficients of different temperature and humidity sample pools are counted, the temperature and humidity deviation values are calculated by calculating the difference between different temperature and humidity and the allowed temperature and humidity range, and the temperature and humidity deviation values and the corresponding light intensity attenuation correlation coefficients are integrated into a temperature and humidity-light intensity attenuation correlation coefficient table.

[0071] W3, the corrected light intensity attenuation degree is converted into an electrical signal according to the Lambert-Beer law to obtain the chlorine gas concentration value.

[0072] It should be noted that in the process of electrical signal conversion, the high-precision analog-to-digital converter built in the optical detection module first converts the analog optical signal corresponding to the corrected light intensity attenuation degree into a digital electrical signal, and then substitutes it into the above-mentioned modified Lambert-Beer law formula , wherein is the concentration of the chlorine sample gas, is the optical path length of the sample pool, is the corrected light intensity attenuation degree, is the molar absorption coefficient of the chlorine molecule to the specific wavelength laser used in the present application, and is calibrated and determined by calibration experiment in the present experiment , and the chlorine gas concentration is obtained by operation, which is converted to ppm unit and displayed.

[0073] According to the present application, the corresponding light intensity attenuation correlation coefficient is obtained according to the gas temperature and humidity in the sample pool, the initial light intensity attenuation degree is dynamically compensated and corrected, the corrected light intensity attenuation degree is converted into an electrical signal to obtain the chlorine gas concentration value, the interference of different sample pool temperature and humidity on the light intensity attenuation degree is eliminated, the corrected detection data is more consistent with the actual chlorine gas concentration, and the detection precision is significantly improved.

[0074] The above formulas are all dimensionless values, and the formulas are obtained by software simulation of a large amount of data to obtain a formula closest to the actual situation, and the preset parameters in the formula are set by the person skilled in the art according to the actual situation.

[0075] The above embodiments can be realized by software, hardware, firmware or any combination thereof, in whole or in part. When realized by software, the above embodiments can be realized in the form of a computer program product in whole or in part.

[0076] Those skilled in the art can understand that the modules and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized 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 realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0077] In addition, each functional module in each embodiment of the present application can be integrated in one processing module, or each module can exist physically alone, or two or more modules can be integrated in one module.

[0078] The above is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0079] Finally, the above is only the preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high-precision chlorine on-line detector, characterized in that, The method comprises the following steps: A sample gas collection module is used to determine whether the inner wall of the heat tracing sampling pipeline needs to be cleaned, and the heat tracing sampling pipeline is cleaned when needed, and the chlorine sample gas is extracted at a constant speed by a diaphragm pump after cleaning; A pipeline heating temperature setting module is used to collect the humidity of the chlorine sample gas, and the heating temperature gradient is determined by difference analysis of the set chlorine allowed humidity; A sample gas dehumidification processing module is used to collect the temperature and humidity of the chlorine sample gas after the initial heating treatment, and the heating temperature of the remaining pipeline area is set if the re-collected humidity is greater than the set chlorine allowed humidity, otherwise the constant temperature is maintained; A pretreatment module is used to maintain a constant temperature in the gas filtration area, and impurity filtration is performed on the sample gas after dehumidification treatment; An optical detection module is used to emit a light beam through the sample cell using a specific wavelength laser light source that completely matches the absorption peak of chlorine molecules, and the initial light intensity attenuation is obtained by a high-precision photodetector; A dynamic correction module is used to collect the temperature and humidity of the gas in the sample cell, determine the light intensity attenuation correlation at the temperature and humidity according to the preset temperature and humidity-light intensity attenuation correlation table, dynamically compensate and correct the initial light intensity attenuation, obtain the corrected light intensity attenuation, and convert the corrected light intensity attenuation into an electrical signal to obtain the chlorine concentration value.

2. The high-precision chlorine on-line detector according to claim 1, characterized in 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 collect real-time images of the inner wall of the heat tracing sampling pipeline, and the color images collected in real time are subjected to fog removal and noise reduction processing, and a spectrometer is used to collect characteristic spectrum images of the heat tracing sampling pipeline; Image visual texture features are extracted from the color images subjected to fog removal and noise reduction processing, and spectral intensity features and reflectivity features are extracted from the characteristic spectrum images; The color images subjected to fog removal and noise reduction processing and the characteristic spectrum images are compared with the original color images and characteristic spectrum images of the clean pipeline, respectively, the image visual texture features, spectral intensity features and inner wall reflectivity features are compared with the corresponding standard features of the clean pipeline, and it is determined whether there is a difference, if there is a difference, it is determined that the heat tracing sampling pipeline needs to be cleaned, otherwise it is determined that the heat tracing sampling pipeline does not need to be cleaned.

3. The high-precision chlorine on-line detector according to claim 2, characterized in 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 images subjected to fog removal and noise reduction to obtain a gray level co-occurrence matrix, and the key parameters of the image visual texture features are calculated through the gray level co-occurrence matrix, wherein the key parameters include energy parameters, contrast parameters and correlation parameters, the parameter difference between the collected color images and the original color images is calculated, and the calculated parameter difference is compared with the set difference judgment rule to determine whether there is a difference in the image visual texture features; The spectral intensity features of the key wavebands are extracted from the real-time collected characteristic spectrum images, the standard spectral intensity features of the corresponding key wavebands in the original characteristic spectrum images of the clean pipeline are called, the difference between the spectral intensity features and the standard spectral intensity features is calculated, and the difference is compared with the set difference threshold value, if the difference exceeds the set difference threshold value, 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 of the inner wall reflectivity characteristics are obtained by the characteristic spectrum, wherein the parameters include the inner wall original light intensity count, the dark current light intensity count and the standard plate original light intensity count, the original light intensity count, the dark current light intensity count and the standard plate original light intensity count are brought into the reflectivity calculation formula to obtain the reflectivity corresponding to the collected characteristic spectrum, the reflectivity is compared with the standard reflectivity calculated from the original characteristic spectrum, if the reflectivity exceeds the set range of the standard reflectivity, it is judged that the inner wall reflectivity characteristics have differences, otherwise, it is judged that the inner wall reflectivity characteristics have no differences.

4. The high-precision chlorine on-line detector according to claim 1, characterized in that: The specific content of the pipeline heating temperature setting module is as follows: A corrosion-resistant grid is installed at the gas inlet of the heat tracing sampling pipeline, each intersection of the grid is set as a collection point, the humidity of each collection point is collected, and the average humidity of each collection point is calculated as the initial humidity of the sample gas; The initial humidity and the set allowable humidity of chlorine gas are analyzed by difference to determine the humidity deviation value; The pipeline between the two humidity collection devices in the heat tracing sampling pipeline is divided into segments according to equal length, a heating device is arranged in the middle of each segment, and the heating temperature of each segment is set according to the humidity deviation value.

5. The high-precision chlorine on-line detector according to claim 4, characterized in that: The heating temperature setting method of each segment is as follows: The humidity deviation value is equally divided according to the number of segments of the heat tracing sampling pipeline to obtain the target humidity at the end of each segment; According to the segment length, the chlorine gas humidity and pipeline heating temperature correlation mapping table corresponding to the segment length is extracted from the chlorine gas humidity and pipeline heating temperature correlation mapping table; The initial humidity and the target humidity of each segment are brought into the screened chlorine gas humidity and pipeline heating temperature correlation mapping table to determine the heating temperature of each segment.

6. The high-precision chlorine on-line detector according to claim 5, characterized in that: The chlorine gas humidity and pipeline heating temperature correlation mapping table is established as follows: A large number of chlorine gas sample humidity heating experiments are set, and the large number of chlorine gas sample humidity heating experiments are divided into heating experiments of different pipeline lengths; Different initial humidities of chlorine gas are introduced into the heat tracing sampling pipelines corresponding to the heating experiments of different pipeline lengths, and the introduction speed of chlorine gas is the same in different heating experiments; The heat tracing sampling pipelines with different initial humidity of chlorine gas introduced therein are heated at different heating temperatures, and the humidity of the heated chlorine gas sample is measured; The chlorine gas sample humidity of different initial humidities at different heating temperatures in different pipeline length heating experiments is counted and integrated into a chlorine gas humidity and pipeline heating temperature correlation mapping table.

7. The high-precision chlorine on-line detector according to claim 6, characterized in that: The heating temperature setting method of the remaining pipeline region is as follows: The humidity of the heated chlorine gas sample, the set allowable humidity of chlorine gas and the remaining pipeline length are brought into the chlorine gas humidity and pipeline heating temperature correlation mapping table to output the heating temperature, and the heating temperature of the remaining pipeline region is set to the output heating temperature.

8. The high-precision chlorine on-line detector according to claim 7, characterized in that: The setting value determination method of the constant temperature maintaining is as follows: When the re-collected chlorine gas sample humidity is lower than the set allowable humidity of chlorine gas, the heating temperature of the remaining pipeline region is maintained at the temperature of the re-collected heated chlorine gas sample according to the temperature of the re-collected heated chlorine gas sample.

9. The high-precision chlorine on-line detector according to claim 1, characterized in that: The main content of the dynamic correction module is: The temperature and humidity of the sample cell are collected in real time, and the temperature and humidity of the sample cell are compared with the set temperature and humidity range of the chlorine gas not affected by the environment to obtain a temperature and humidity deviation value; The temperature and humidity- light intensity attenuation correlation coefficient table is queried to obtain the light intensity attenuation correlation coefficient corresponding to the temperature and humidity deviation value, and the corrected light intensity attenuation degree is calculated by the product of the light intensity attenuation correlation coefficient and the initial light intensity attenuation degree; The corrected light intensity attenuation degree is converted into an electrical signal according to the Lambert-Beer law to obtain a chlorine concentration value.

10. The high-precision chlorine on-line detector according to claim 9, characterized in that: The temperature and humidity- light intensity attenuation correlation coefficient table is constructed in the following manner: Chlorine gas concentration test experiments are performed on sample cells with different temperatures and humidities, and the same concentration of chlorine gas is introduced into the sample cells with different temperatures and humidities, and the light intensity attenuation degree is measured by a chlorine online detector; The theoretical light intensity attenuation degree is determined according to the concentration of the introduced chlorine gas by the Lambert-Beer law, and the ratio of the theoretical light intensity attenuation degree to the measured light intensity attenuation degree is used as the light intensity attenuation correlation coefficient; The light intensity attenuation correlation coefficients of the sample cells with different temperatures and humidities are counted, the temperature and humidity deviation values are calculated by comparing the different temperatures and humidities with the allowed temperature and humidity range, and the temperature and humidity deviation values and the corresponding light intensity attenuation correlation coefficients are integrated into the temperature and humidity- light intensity attenuation correlation coefficient table.

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