Multi-component gas ndir synchronous monitoring and intelligent calibration method

Abstract

This application discloses a method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR, relating to the field of gas detection technology. It solves the technical problem of low accuracy in gas concentration detection results caused by overlapping absorption spectra between different gases in existing non-dispersive infrared gas detection technologies. The method includes: determining several first and second detection gases based on spectral absorption data; a first wavelength channel corresponding to the first detection gas; calculating the gas concentration of the first detection gas corresponding to the first spectral signal based on the first spectral signal and the incident spectral signal; selecting several interfering gases corresponding to each second detection gas based on the gas concentrations corresponding to the several first detection gases, and determining the second wavelength channel of the second detection gas; calculating the corresponding gas concentration of the second detection gas based on the second spectral signal, the incident spectral signal, and the gas concentrations corresponding to the interfering gases; thus improving the detection accuracy of gas concentration.

Description

Technical Field

[0001] This application belongs to the field of gas detection technology, specifically a method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR. Background Technology

[0002] Currently, nondispersive infrared (NDIR) gas detection technology is widely used in environmental monitoring, industrial process control, and other fields due to its advantages such as good selectivity, long service life, and high reliability. The basic principle of NDIR detection is based on Lambert-Beer's law, which utilizes the absorption characteristics of gases to infrared light of specific wavelengths to measure gas concentration.

[0003] However, in practical applications, especially in multi-component gas monitoring scenarios, different gases may exhibit overlapping absorption spectra in similar infrared bands, resulting in cross-interference. Existing solutions typically employ narrowband filters or complex algorithm compensation. However, narrowband filters are expensive and difficult to completely eliminate interference, while traditional algorithm compensation often relies on fixed interference models, making it difficult to adapt to complex and variable gas environments. Consequently, the accuracy and reliability of detection results are low when simultaneously monitoring multi-component gases. Summary of the Invention

[0004] This application provides a method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR, which solves the technical problem of low accuracy of gas concentration detection results caused by the overlap of absorption spectra between different gases in the application of existing non-dispersive infrared gas detection technology for multi-component gas detection.

[0005] To achieve the above objectives, this application adopts the following technical solution: Firstly, a method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR is provided, including: Acquire spectral absorption data of several gases to be tested, and determine several first detection gases and second detection gases based on the spectral absorption data; and a first wavelength channel corresponding to the first detection gas; the gases to be tested are gases to be detected in the gas sample to be detected, such as carbon dioxide, nitrogen dioxide and sulfur dioxide, etc. The first gas to be detected is detected, and the first spectral signal and the incident spectral signal under the first wavelength channel are acquired; the gas concentration of the first gas to be detected corresponding to the first spectral signal is calculated based on the first spectral signal and the incident spectral signal. Based on the gas concentrations corresponding to several first detection gases, select several interfering gases corresponding to each second detection gas, and determine the second wavelength channel of the second detection gas. Several second detection gases are detected, and the second spectral signal and incident spectral signal under the second wavelength channel corresponding to each second detection gas are obtained; the gas concentration of the corresponding second detection gas is calculated based on the second spectral signal, the incident spectral signal and the gas concentration of the interfering gas.

[0006] Based on the above technical solution, in the multi-component gas NDIR synchronous monitoring and intelligent calibration method provided in this application, the gas to be tested is divided into a first detection gas and a second detection gas by calculating the purity of the spectral absorption data. The first detection gas, which has high purity and is less affected by interference, is detected first. Then, for the second detection gas, which is severely affected by interference, the concentration of the first detection gas that has been measured is used as the known concentration of the interfering gas for calibration. The optimal detection channel is selected by combining the wavelength channel screening function, and the influence of the interfering gas is subtracted by iterative calculation. This method starts from the essential characteristics of spectral data, realizes the intelligent selection of detection objects and detection channels, and effectively solves the cross-interference problem in multi-component gas detection through a hierarchical calibration strategy, significantly improving the detection accuracy of gas concentration and the robustness of the system.

[0007] In conjunction with the first aspect described above, in one possible implementation, a plurality of first and second detection gases are determined based on the spectral absorption data; and a first wavelength channel corresponding to the first detection gas is included: Extract the absorption coefficients of the corresponding gas at different wavelengths from each spectral absorption data set; the spectral absorption data are obtained by consulting spectral databases or experimental measurements; the absorption coefficient represents the gas's ability to absorb light at that wavelength, i.e., its absorbance; construct an absorption coefficient matrix based on the absorption coefficients of each gas at different wavelengths; one form of expression for the absorption coefficient matrix includes: ; Where A is the absorption coefficient matrix. Let m be the absorption coefficient of the i-th gas at the j-th wavelength, m be the number of gas types, and n be the number of wavelengths. The purity of each gas to be tested at different wavelengths is generated based on the absorption coefficient matrix; the first wavelength channel corresponding to the first detection gas, the second detection gas, and the first detection gas is determined based on the purity.

[0008] In conjunction with the first aspect above, in one possible implementation, generating the purity of each gas to be tested at different wavelengths based on the absorption coefficient matrix includes: Obtain each element in the absorption coefficient matrix; select any element as the target element, and substitute the target element and all elements in its column into a set purity calculation function to obtain the purity corresponding to the target element; one expression of the purity calculation function includes: ; in, This represents the purity of the element in the i-th row and j-th column of the absorption coefficient matrix, i.e., the purity of the i-th gas at the j-th wavelength. The closer the purity value is to 1, the less interference from other gases there is when the concentration of the gas to be tested is detected at that wavelength, and the higher the accuracy of subsequent concentration detection. is the element in the i-th row and j-th column of the absorption coefficient matrix, that is, the absorption coefficient of the i-th gas at the j-th wavelength; The purity of each element in the absorption matrix is ​​calculated sequentially, that is, the purity of each gas to be tested at different wavelengths.

[0009] In conjunction with the first aspect above, in one possible implementation, determining the first detection gas, the second detection gas, and the first wavelength channel corresponding to the first detection gas based on purity includes: The purity of each gas to be tested is obtained at each wavelength. When the purity of the gas to be tested is greater than the set purity threshold, the gas to be tested is recorded as the first detection gas, and the wavelength corresponding to the purity is recorded as the preliminary wavelength channel. The preliminary wavelength channel is filtered to obtain the first wavelength channel; otherwise, it is recorded as the second detection gas.

[0010] In conjunction with the first aspect above, in one possible implementation, the preliminary wavelength channel screening to obtain the first wavelength channel includes: Select several initial wavelength channels corresponding to any first detection gas; Obtain a set wavelength step size; determine the wavelength neighborhood corresponding to the initial wavelength channel with the initial wavelength channel as the center and the wavelength step size as the radius; obtain the purity of the first detection gas at each wavelength within the wavelength neighborhood; substitute the purity into a set reference purity calculation function to obtain the reference purity corresponding to the initial wavelength channel; one expression of the reference purity calculation function includes: ; in, Let be the reference purity of the i-th gas to be tested at the j-th wavelength; For windows; D is the set wavelength step size. Specifically, when d=1, a window is constructed that only contains the initial wavelength channel and the first detection gas at the wavelength before and after the initial wavelength channel. The overall purity within this window is calculated as the reference purity. For the i-th gas to be tested, the weighting coefficient for the purity corresponding to the k-th wavelength in the d-th window of a certain initial wavelength channel; The initial wavelength channel with the highest reference purity value is selected as the first wavelength channel corresponding to the first detection gas, and the wavelength range corresponding to the window d of the reference purity value of the first wavelength channel is recorded as the half-width; the first wavelength channels corresponding to each first detection gas are obtained in sequence.

[0011] In conjunction with the first aspect above, in one possible implementation, the step of selecting several interfering gases corresponding to each second detection gas based on the gas concentrations corresponding to several first detection gases, and determining the second wavelength channel of the second detection gas, includes: Select any second detection gas as the target detection gas, obtain the absorption coefficient at different wavelengths in the spectral absorption data corresponding to the target detection gas, and record the wavelengths with non-zero absorption coefficients as candidate wavelength channels. Obtain the absorption coefficients of several gases to be tested in each candidate wavelength channel; when the absorption coefficient is not zero, the gas to be tested is recorded as a candidate interfering gas of the target detection gas in the corresponding candidate wavelength channel; When the candidate interfering gas is the first detection gas, the candidate interfering gas is recorded as the calibration interfering gas; otherwise, the candidate interfering gas is recorded as another interfering gas. Calculate the purity and reference purity of the target gas in each candidate wavelength channel; select the candidate wavelength channel based on the purity, reference purity and candidate interfering gas to obtain the second wavelength channel and the interfering gas corresponding to the second wavelength channel; Each second detection gas is sequentially used as the target detection gas, and its corresponding second wavelength channel and the interfering gas corresponding to the second wavelength channel are selected.

[0012] In conjunction with the first aspect above, in one possible implementation, selecting a second wavelength channel and the corresponding interfering gas based on the purity, reference purity, and candidate interfering gas for the candidate wavelength channel includes: A wavelength channel selection function is constructed based on the purity of each candidate wavelength channel, the reference purity, and the concentration of candidate interfering gases. The second wavelength channel is obtained by solving the wavelength channel selection function. One expression of the wavelength channel selection function includes: ; in, The second wavelength channel selected for the second detection gas, numbered g. Let g be the purity of the second detected gas at the candidate wavelength channel j. The reference purity of the second detected gas (g) in the candidate wavelength channel (j) is given by the value of g. To interfere with gas adaptability; , and For the corresponding weight coefficients, and ; The calibration interference gas and gas interference gas corresponding to the second wavelength channel are obtained and denoted as interference gas.

[0013] In conjunction with the first aspect above, in one possible implementation, the gas disturbance adaptability... One calculation method includes: ; in, This is the set of calibration interference gases for the candidate wavelength channel corresponding to number j; This is the set of other interfering gases in the candidate wavelength channel corresponding to number j; To calibrate the interfering gas collection The gas concentration corresponding to internal number i; The set standard gas concentration; The concentration penalty coefficient is set. Other interfering gases are penalized as specified; To calibrate the length of the interfering gas set, i.e., the number of internal standard interfering gases; The length of the set of other interfering gases is the number of internal standard interfering gases.

[0014] In conjunction with the first aspect described above, in one possible implementation, calculating the gas concentration of the first detected gas corresponding to the first spectral signal based on the first spectral signal and the incident spectral signal includes: The light intensity in the first spectral signal is extracted and recorded as the transmitted light intensity in the first wavelength channel, and the light intensity in the incident spectral signal is extracted and recorded as the incident light intensity in the first wavelength channel; the absorption coefficient of the first detection gas in the first wavelength channel is obtained; and the gas concentration of the first detection gas is calculated based on the Lambert-Beer law.

[0015] In conjunction with the first aspect above, in one possible implementation, the gas concentration of the corresponding second detection gas is calculated based on the second spectral signal, the incident spectral signal, and the gas concentration corresponding to the interfering gas, including: S1: Obtain the interfering gas corresponding to each second detection gas; S2: Obtain the second detection gas from all interfering gases, which contains only the standard interfering gas; S3: Acquire the second spectral signal and incident spectral signal of the second detection gas in the second channel; extract the light intensity from the second spectral signal and record it as the transmitted light intensity in the second channel, extract the light intensity from the incident spectral signal and record it as the incident light intensity in the second channel, acquire the absorption coefficient of the second detection gas in the second wavelength channel, and the gas concentration of each standard interfering gas in the interfering gas and its absorption coefficient in the second wavelength channel; calculate the gas concentration of the second detection gas based on the Lambert-Beer law; S4: Determine if there is a second detection gas whose gas concentration has not been calculated; if yes, obtain other interfering gases in the interfering gases corresponding to the remaining second detection gases whose gas concentration has not been calculated, and record the other interfering gases that are the same as the second detection gases whose gas concentration has been calculated as calibration interfering gases, and proceed to S2; if no, output the gas concentration of all second detection gases.

[0016] This application provides a method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR. It can divide the gas to be tested into a first detection gas and a second detection gas by calculating the purity of the spectral absorption data, prioritizing the detection of the first detection gas, which has high purity and is less susceptible to interference. Then, for the second detection gas, which is severely interfered with, the measured concentration of the first detection gas is used as a known concentration of the interfering gas for calibration. The optimal detection channel is selected by combining a wavelength channel selection function, and the influence of the interfering gas is subtracted through iterative calculation. This method, starting from the essential characteristics of spectral data, achieves intelligent optimization of the detection object and detection channel, and effectively solves the problem of cross-interference in multi-component gas detection through a hierarchical calibration strategy, significantly improving the detection accuracy of gas concentration and the robustness of the system.

[0017] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. 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 illustrating the steps of the multi-component gas NDIR synchronous monitoring and intelligent calibration method in this application. Detailed Implementation

[0020] The technical solutions of this application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] Please see Figure 1 The first aspect of this application provides a method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR, including: The method involves acquiring spectral absorption data of several target gases, determining several first and second detection gases based on the spectral absorption data, and identifying a first wavelength channel corresponding to the first detection gas. Specifically, the target gas refers to the target gas component in the gas sample whose concentration needs to be detected, such as carbon dioxide, sulfur dioxide, and nitric oxide. Spectral absorption data reflects the absorption characteristics of a gas to different wavelengths of infrared light and can usually be obtained in advance by consulting standard spectral databases, such as the HITRAN database, or through experimental measurements. This embodiment identifies the absorption characteristics and overlap of each target gas at different wavelengths by analyzing the spectral absorption data. The first detection gas refers to a gas whose spectral absorption signal is less affected by other target gases and has high purity at a specific wavelength channel; the second detection gas refers to a gas whose spectral absorption signal is significantly affected by other gases at all selectable wavelength channels. The first detection gas is detected, and the first spectral signal and incident spectral signal under the first wavelength channel are acquired. The gas concentration of the first detection gas corresponding to the first spectral signal is calculated based on the first spectral signal and the incident spectral signal. Since the first detection gas is minimally affected by interference under the selected first wavelength channel, its detection process is relatively independent and accurate. The NDIR sensor acquires the transmitted light intensity, i.e., the first spectral signal, and the incident light intensity, i.e., the incident spectral signal, under the first wavelength channel. Based on Lambert-Beer's law, the degree of light intensity attenuation is positively correlated with the gas concentration, so the accurate concentration of the first detection gas can be directly calculated. The concentration calculation result of the first detection gas will be used as a "known quantity" or "calibration benchmark" in subsequent steps to assist in calculating the concentration of the second detection gas, which is subject to severe interference.

[0022] Based on the gas concentrations corresponding to several first detection gases, several interfering gases corresponding to each second detection gas are selected, and the second wavelength channels of the second detection gases are determined. Specifically, this step is the key to establishing the interference model. For each second detection gas, the system analyzes its spectral absorption data to find out which wavelength channels have absorption, i.e., the absorption coefficient is not zero. These channels are the candidate wavelength channels. If other gases to be measured also have absorption in the candidate wavelength channels, they are marked as candidate interfering gases.

[0023] Several second detection gases are detected, and the second spectral signal and incident spectral signal under the corresponding second wavelength channel for each second detection gas are acquired. Based on the second spectral signal, the incident spectral signal, and the gas concentration of the interfering gas, the gas concentration of the corresponding second detection gas is calculated. Specifically, after determining the second wavelength channel and its corresponding interfering gas, the NDIR sensor collects the transmitted light intensity, the second spectral signal, and the incident light intensity under the second wavelength channel. Because the second spectral signal contains the absorption contribution of the interfering gas, this embodiment constructs a system of equations containing multiple variables or uses an iterative subtraction method to separate the absorption component of the interfering gas from the total absorption signal, thereby accurately calculating the true concentration of the second detection gas. Through the above steps, this embodiment achieves a detection process from easy to difficult, with step-by-step calibration, effectively eliminating cross-interference between multi-component gases and significantly improving the accuracy and reliability of concentration monitoring in complex gas environments.

[0024] Based on the above technical solution, in the multi-component gas NDIR synchronous monitoring and intelligent calibration method provided in this application, the gas to be tested is divided into a first detection gas and a second detection gas by calculating the purity of the spectral absorption data. The first detection gas, which has high purity and is less affected by interference, is detected first. Then, for the second detection gas, which is severely affected by interference, the concentration of the first detection gas that has been measured is used as the known concentration of the interfering gas for calibration. The optimal detection channel is selected by combining the wavelength channel screening function, and the influence of the interfering gas is subtracted by iterative calculation. This method starts from the essential characteristics of spectral data, realizes the intelligent selection of detection objects and detection channels, and effectively solves the cross-interference problem in multi-component gas detection through a hierarchical calibration strategy, significantly improving the detection accuracy of gas concentration and the robustness of the system.

[0025] In one possible implementation, several first and second detection gases are determined based on spectral absorption data; and a first wavelength channel corresponding to the first detection gas is defined, including: extracting the absorption coefficients of the corresponding gas at different wavelengths from each spectral absorption data; the spectral absorption data is acquired by consulting a spectral database or through experimental measurement; the absorption coefficient is the magnitude of the gas's ability to absorb light at that wavelength, i.e., the absorbance; an absorption coefficient matrix is ​​constructed based on the absorption coefficients of each gas at different wavelengths; one form of expression for the absorption coefficient matrix includes: ; Where A is the absorption coefficient matrix. Let m be the absorption coefficient of the i-th gas at the j-th wavelength, m be the number of gas types, and n be the number of wavelengths. The purity of each gas to be tested at different wavelengths is generated based on the absorption coefficient matrix. The purity is used to determine the first detection gas, the second detection gas, and the first wavelength channel corresponding to the first detection gas. In this embodiment, the continuous spectral curve is discretized and sampled within a preset wavelength range. Assuming there are m types of gases to be tested and n wavelength sampling points are preset, an m x n absorption coefficient matrix A can be constructed. The element aij in the matrix represents the absorption coefficient of the i-th gas at the j-th wavelength. The absorption coefficient is an inherent property characterizing the absorption capacity of a gas; the larger the value, the stronger the absorption of that wavelength of light. Expressed in matrix form, the absorption overlap of different gases at different wavelengths can be clearly shown, providing a data basis for subsequent interference analysis.

[0026] In one possible implementation, generating the purity of each gas to be tested at different wavelengths based on the absorption coefficient matrix includes: obtaining each element in the absorption coefficient matrix; selecting any element as the target element, and substituting the target element and all elements in its column into a set purity calculation function to obtain the purity corresponding to the target element; one expression of the purity calculation function includes: ; in, This represents the purity of the element in the i-th row and j-th column of the absorption coefficient matrix, i.e., the purity of the i-th gas at the j-th wavelength. The closer the purity value is to 1, the less interference from other gases there is when the concentration of the gas to be tested is detected at that wavelength, and the higher the accuracy of subsequent concentration detection. is the element in the i-th row and j-th column of the absorption coefficient matrix, that is, the absorption coefficient of the i-th gas at the j-th wavelength; The purity of each element in the absorption matrix is ​​calculated sequentially, that is, the purity of each gas to be tested at different wavelengths.

[0027] In one possible implementation, determining the first detection gas, the second detection gas, and the first wavelength channel corresponding to the first detection gas based on purity includes: acquiring the purity of each gas to be tested at each wavelength; when the gas to be tested has a purity greater than a set purity threshold, the gas to be tested is recorded as the first detection gas, and the wavelength corresponding to the purity is recorded as the preliminary wavelength channel; the preliminary wavelength channel is then filtered to obtain the first wavelength channel; otherwise, it is recorded as the second detection gas.

[0028] The set purity threshold is a key parameter for distinguishing between two types of gases. For example, it can be set to 0.8 or 0.9. If the purity of a gas exceeds the threshold at at least one wavelength, it indicates the existence of a "quasi-exclusive" absorption channel, which can be classified as the first gas to be detected and given priority for direct measurement.

[0029] In one possible implementation, the first wavelength channel is obtained by preliminary wavelength channel screening, including: selecting several initial wavelength channels corresponding to any first detection gas; Obtain a set wavelength step size; determine the wavelength neighborhood corresponding to the initial wavelength channel with the initial wavelength channel as the center and the wavelength step size as the radius; obtain the purity of the first detection gas at each wavelength within the wavelength neighborhood; substitute the purity into a set reference purity calculation function to obtain the reference purity corresponding to the initial wavelength channel; one expression of the reference purity calculation function includes: ; in, Let be the reference purity of the i-th gas to be tested at the j-th wavelength; For windows; D is the set wavelength step size. Specifically, when d=1, a window is constructed that only contains the initial wavelength channel and the first detection gas at the wavelength before and after the initial wavelength channel. The overall purity within this window is calculated as the reference purity. This is the weighting coefficient for the purity of the i-th gas at the k-th wavelength within the d-th window of a certain initial wavelength channel; in this embodiment, the weighting coefficient is calculated using the following formula. : ; in, The set adjustment coefficient is used to control the decay rate of the weighting coefficient; the adjustment coefficient in this embodiment... The weighting coefficients are distributed according to a Gaussian weighting pattern, maximizing the contribution at the center wavelength within the window and decreasing it as the wavelength moves further away. This Gaussian weighting mechanism ensures that points closer to the center wavelength contribute more, while points farther away contribute less. By calculating the reference purity of each initial wavelength channel and selecting the channel corresponding to the maximum value as the final first wavelength channel, the optimal detection channel with both high absorption intensity and good anti-interference stability can be effectively screened. This avoids the random errors of single-wavelength data and significantly improves the reliability of the first detected gas concentration measurement. The initial wavelength channel with the highest reference purity value is selected as the first wavelength channel corresponding to the first detection gas, and the wavelength range corresponding to the window d of the reference purity value of the first wavelength channel is recorded as the half-width; the first wavelength channels corresponding to each first detection gas are obtained in sequence.

[0030] In one possible implementation, several interfering gases corresponding to each second detection gas are selected based on the gas concentrations corresponding to several first detection gases, and a second wavelength channel for each second detection gas is determined, including: Select any second detection gas as the target detection gas, obtain the absorption coefficient at different wavelengths in the spectral absorption data corresponding to the target detection gas, and record the wavelengths with non-zero absorption coefficients as candidate wavelength channels. The absorption coefficients of several test gases at various candidate wavelength channels are obtained. When the absorption coefficient is not zero, the test gas is recorded as a candidate interfering gas of the target detection gas at the corresponding candidate wavelength channel. It can be understood that the candidate interfering gas corresponds to the target detection gas, and the target detection gas has several corresponding candidate interfering gases at each candidate wavelength. In conventional gas concentration detection, the gas concentration is usually calculated by the change in light intensity of the gas at a certain wavelength. Since multiple gases may absorb light at a certain wavelength, if the above method is used for gas concentration detection, the detected gas concentration will be affected by other gases that absorb light at that wavelength, which will lead to errors in the concentration of the detected gas. When the candidate interfering gas is the first detection gas, the candidate interfering gas is recorded as the calibration interfering gas; otherwise, the candidate interfering gas is recorded as another interfering gas. Calculate the purity and reference purity of the target gas in each candidate wavelength channel; select the candidate wavelength channel based on the purity, reference purity and candidate interfering gas to obtain the second wavelength channel and the interfering gas corresponding to the second wavelength channel; Each second detection gas is sequentially used as the target detection gas, and its corresponding second wavelength channel and the interfering gas corresponding to the second wavelength channel are selected.

[0031] In one possible implementation, a second wavelength channel and the corresponding interfering gas are obtained by selecting candidate wavelength channels based on purity, reference purity, and candidate interfering gases, including: A wavelength channel selection function is constructed based on the purity of each candidate wavelength channel, the reference purity, and the concentration of candidate interfering gases. The second wavelength channel is obtained by solving the wavelength channel selection function. One expression of the wavelength channel selection function includes: ; in, The second wavelength channel selected for the second detection gas, numbered g. Let g be the purity of the second detected gas at the candidate wavelength channel j. The reference purity of the second detected gas (g) in the candidate wavelength channel (j) is given by the value of g. To interfere with gas adaptability; , and For the corresponding weight coefficients, and ; and The weighting focuses on the stability and anti-interference potential of the spectral signal itself, while The weighting focuses on the manageability of the interference source. The calibration interference gas and gas interference gas corresponding to the second wavelength channel are obtained and denoted as interference gas.

[0032] In one possible implementation, the gas-disrupting fitness One calculation method includes: ; in, This is the set of calibration interference gases for the candidate wavelength channel corresponding to number j; This is the set of other interfering gases in the candidate wavelength channel corresponding to number j; To calibrate the interfering gas collection The gas concentration corresponding to internal number i; The set standard gas concentration is used to quantify the gas concentration and remove the dimensions. The concentration penalty coefficient is set to increase the difference in the adaptability of the interference gas corresponding to high and low concentrations of the calibration interference gas. The penalty factor for other interfering gases is set to increase the penalty for the presence of other interfering gases, and That is, when the only candidate interfering gas among the candidate wavelength channels is the calibration interfering gas, that type of candidate wavelength channel is preferred; when only candidate wavelength channels containing both calibration interfering gas and other interfering gases exist, the candidate wavelength channel with a larger proportion of calibration interfering gas is preferred; in this embodiment... , ; To calibrate the length of the interfering gas set, i.e., the number of internal standard interfering gases; The length of the set of other interfering gases is the number of internal standard interfering gases. It can be understood that, since the gas to be tested corresponding to the wavelength channel with high purity is selected as the first detection gas when screening the first detection gas, there is no case of no interfering gas in the second detection gas.

[0033] When there is no calibration interference gas in the candidate wavelength channel Only other interfering gases are present. When unknown interference cannot be subtracted, the fitness of this channel is set to 0, and this wavelength channel is avoided as much as possible. When only calibration interference gas exists in the candidate wavelength channel Ideally, this is the case when no other interfering gases are present. In this situation, fitness depends solely on the concentration of the calibration interfering gas. The lower the concentration, the closer its effect on the second detection gas is to a linear effect; therefore, wavelength channels with low average concentrations of calibration interfering gases are preferred for ease of calculation.

[0034] When calibration interference gas and other interference gases are present in the candidate wavelength channel at the same time, a penalty factor η2 is introduced. At this time, the fitness will decrease because the presence of unknown interference increases the uncertainty of concentration calculation.

[0035] In one possible implementation, calculating the gas concentration of the first detection gas corresponding to the first spectral signal based on the first spectral signal and the incident spectral signal includes: extracting the light intensity from the first spectral signal and recording it as the transmitted light intensity in the first wavelength channel; extracting the light intensity from the incident spectral signal and recording it as the incident light intensity in the first wavelength channel; obtaining the absorption coefficient of the first detection gas in the first wavelength channel; and calculating the gas concentration of the first detection gas based on the Lambert-Beer law.

[0036] Specifically, the Lambert-Beer law describes the quantitative relationship of light absorption by a gas. When a beam of light with intensity... When light passes through a gas chamber filled with the gas to be measured, the light intensity is attenuated due to gas absorption. The emitted light intensity is denoted as . According to Beer-Lambert law, the intensity of transmitted light... With incident light intensity The following relationship exists between them: ; in, The intensity of transmitted light. For the incident light intensity, For gas at wavelength The absorption coefficient below, For gas concentration, Let be the optical path length, i.e., the length of the gas chamber. Taking the natural logarithm of both sides of the above formula and performing mathematical transformations, we can derive the formula for calculating the gas concentration:

[0037] In this embodiment, since the purity of the first detection gas in the first wavelength channel is extremely high, the interference of other gases can be ignored. The gas concentration of each first detection gas can be calculated through the above steps. It is understood that during the measurement process, there may be some interference from equipment or gases that are not the gas to be measured. In order to calculate accurate values, these interferences need to be included in the calculation process. These are all relatively existing technologies, and will not be described in detail here.

[0038] In one possible implementation, the gas concentration of the corresponding second detection gas is calculated based on the second spectral signal, the incident spectral signal, and the gas concentration of the interfering gas, including: S1: Obtain the interfering gas corresponding to each second detection gas; S2: Obtain the second detection gas from all interfering gases, which contains only the standard interfering gas; S3: Obtain the second spectral signal and incident spectral signal of the second detection gas in the second channel; extract the light intensity from the second spectral signal and record it as the transmitted light intensity in the second channel, extract the light intensity from the incident spectral signal and record it as the incident light intensity in the second channel, obtain the absorption coefficient of the second detection gas in the second wavelength channel, and the gas concentration and absorption coefficient of each standard interfering gas in the interfering gas in the second wavelength channel; calculate the gas concentration of the second detection gas based on Lambert-Beer's law; specifically, for this type of second detection gas, its absorption equation can be expressed as: ; in, The absorption coefficient of the target second detection gas in the corresponding second wavelength channel. Its concentration to be determined; and These are the absorption coefficient and gas concentration of the calibrating interfering gas in the second wavelength channel, respectively; based on this, the gas concentration corresponding to the second detection gas can be calculated.

[0039] S4: Determine if there is a second detection gas whose concentration has not been calculated; if yes, obtain other interfering gases among the interfering gases corresponding to the remaining second detection gases whose concentrations have not been calculated, and record the other interfering gases that are the same as the second detection gases whose concentrations have been calculated as calibration interfering gases, and proceed to S2; if no, output the gas concentrations of all second detection gases; it can be understood that the interfering gas is a certain gas to be tested; it is worth noting that when there is a second detection gas whose concentration has not been calculated, there is another situation: when there are two second detection gases whose corresponding interfering gases each contain two other interfering gases, and these two interfering gases are the same two gases to be tested, the two second detection gases can be solved simultaneously; similarly, when there are three second detection gases whose corresponding interfering gases each contain three other interfering gases, and these three interfering gases are the same two gases to be tested, the two second detection gases can be solved simultaneously.

[0040] Specifically, after completing the calculation for the highest priority gas, the system checks if there are any remaining uncalculated gases. If so, the status of the interfering gas list is updated: components that were originally classified as "other interfering gases" are reclassified as "calibration interfering gases" if their concentrations were already calculated in the previous iteration. This dynamic update mechanism gradually decouples the originally complex multi-component coupled equations. For example, if the interfering source of gas B is gas A (known), and the interfering sources of gas C are both gas A and gas B, then in the first iteration, the concentration of gas B is calculated first; in the second iteration, gas B becomes a known quantity, thus making the equations for gas C solvable. Through this progressive iterative logic, this embodiment can effectively handle the complex cross-interference network between multi-component gases, significantly improving the robustness and accuracy of the overall detection system.

[0041] Some of the data in the above formula are calculated by removing dimensions and taking their numerical values. The formula is the closest to the real situation obtained by software simulation of a large amount of collected data. The preset parameters and preset thresholds in the formula are set by those skilled in the art according to the actual situation or obtained through simulation of a large amount of data.

[0042] The above embodiments are only used to illustrate the technical methods of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of this application without departing from the spirit and scope of the technical methods of this application.

Claims

1. A method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR, characterized in that, include: Acquire spectral absorption data of several gases to be tested, and determine several first detection gases and second detection gases based on the spectral absorption data; and a first wavelength channel corresponding to the first detection gas; The first gas to be detected is detected, and the first spectral signal and the incident spectral signal under the first wavelength channel are acquired; The gas concentration of the first detected gas corresponding to the first spectral signal is calculated based on the first spectral signal and the incident spectral signal; Based on the gas concentrations corresponding to several first detection gases, select several interfering gases corresponding to each second detection gas, and determine the second wavelength channel of the second detection gas. Several second detection gases are detected, and the second spectral signal and incident spectral signal of each second detection gas under the corresponding second wavelength channel are obtained; The gas concentration of the corresponding second detection gas is calculated based on the second spectral signal, the incident spectral signal, and the gas concentration of the interfering gas.

2. The method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR according to claim 1, characterized in that, Based on the spectral absorption data, several first and second detection gases are determined; and a first wavelength channel corresponding to the first detection gas is included: Extract the absorption coefficients of the gas to be tested at different wavelengths from each spectral absorption data; construct an absorption coefficient matrix based on the absorption coefficients of each gas to be tested at different wavelengths. The purity of each gas to be tested at different wavelengths is generated based on the absorption coefficient matrix; the first wavelength channel corresponding to the first detection gas, the second detection gas, and the first detection gas is determined based on the purity.

3. The method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR according to claim 2, characterized in that, The process of generating the purity of each gas under test at different wavelengths based on the absorption coefficient matrix includes: Obtain each element in the absorption coefficient matrix; select any element as the target element, and substitute the target element and all elements in its column into the set purity calculation function to obtain the purity corresponding to the target element; The purity of each element in the absorption matrix is ​​calculated sequentially, that is, the purity of each gas to be tested at different wavelengths.

4. The method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR according to claim 2, characterized in that, The determination of the first detection gas, the second detection gas, and the first wavelength channel corresponding to the first detection gas based on purity includes: The purity of each gas to be tested is obtained at each wavelength. When the purity of the gas to be tested is greater than the set purity threshold, the gas to be tested is recorded as the first detection gas, and the wavelength corresponding to the purity is recorded as the preliminary wavelength channel. The preliminary wavelength channel is filtered to obtain the first wavelength channel; otherwise, it is recorded as the second detection gas.

5. The method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR according to claim 4, characterized in that, The process of obtaining the first wavelength channel through preliminary wavelength channel screening includes: Select several initial wavelength channels corresponding to any first detection gas; Obtain the set wavelength step size; determine the wavelength neighborhood corresponding to the initial wavelength channel with the initial wavelength channel as the center and the wavelength step size as the radius; obtain the purity of the first detection gas at each wavelength within the wavelength neighborhood; substitute the purity into the set reference purity calculation function to obtain the reference purity corresponding to the initial wavelength channel; The initial wavelength channel with the highest reference purity value is selected as the first wavelength channel corresponding to the first detection gas; the first wavelength channels corresponding to each first detection gas are obtained sequentially.

6. The method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR according to claim 1, characterized in that, The step of selecting several interfering gases corresponding to each second detection gas based on the gas concentrations corresponding to several first detection gases, and determining the second wavelength channel of the second detection gas, includes: Select any second detection gas as the target detection gas, obtain the absorption coefficient at different wavelengths in the spectral absorption data corresponding to the target detection gas, and record the wavelengths with non-zero absorption coefficients as candidate wavelength channels. Obtain the absorption coefficients of several gases to be tested in each candidate wavelength channel; when the absorption coefficient is not zero, the gas to be tested is recorded as a candidate interfering gas of the target detection gas in the corresponding candidate wavelength channel; When the candidate interfering gas is the first detection gas, the candidate interfering gas is recorded as the calibration interfering gas; otherwise, the candidate interfering gas is recorded as another interfering gas. Calculate the purity and reference purity of the target gas in each candidate wavelength channel; select the candidate wavelength channel based on the purity, reference purity and candidate interfering gas to obtain the second wavelength channel and the interfering gas corresponding to the second wavelength channel; Each second detection gas is sequentially used as the target detection gas, and its corresponding second wavelength channel and the interfering gas corresponding to the second wavelength channel are selected.

7. The method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR according to claim 6, characterized in that, Based on the purity, reference purity, and candidate interfering gases, candidate wavelength channels are selected to obtain the second wavelength channel and the corresponding interfering gases, including: A wavelength channel selection function is constructed based on the purity of each candidate wavelength channel, the reference purity, and the concentration of candidate interfering gases. The second wavelength channel is obtained by solving the wavelength channel selection function. One expression of the wavelength channel selection function includes: ； in, The second wavelength channel selected for the second detection gas, numbered g. Let g be the purity of the second detected gas at the candidate wavelength channel j. The reference purity of the second detected gas (g) in the candidate wavelength channel (j) is given by the value of g. To interfere with gas adaptability; , and For the corresponding weight coefficients, and ; The calibration interference gas and gas interference gas corresponding to the second wavelength channel are obtained and denoted as interference gas.

8. The method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR according to claim 1, characterized in that, Calculating the gas concentration of the first detected gas corresponding to the first spectral signal based on the first spectral signal and the incident spectral signal includes: The light intensity in the first spectral signal is extracted and recorded as the transmitted light intensity in the first wavelength channel, and the light intensity in the incident spectral signal is extracted and recorded as the incident light intensity in the first wavelength channel; the absorption coefficient of the first detection gas in the first wavelength channel is obtained; and the gas concentration of the first detection gas is calculated based on Beer-Lambert's law.

9. The method for simultaneous monitoring and intelligent calibration of multi-component gas NDIR according to claim 1, characterized in that, The gas concentration of the corresponding second detection gas is calculated based on the second spectral signal, the incident spectral signal, and the gas concentration of the interfering gas, including: S1: Obtain the interfering gas corresponding to each second detection gas; S2: Obtain the second detection gas from all interfering gases, which contains only the standard interfering gas; S3: Acquire the second spectral signal and incident spectral signal of the second detection gas in the second channel; extract the light intensity from the second spectral signal and record it as the transmitted light intensity in the second channel, extract the light intensity from the incident spectral signal and record it as the incident light intensity in the second channel, acquire the absorption coefficient of the second detection gas in the second wavelength channel, and the gas concentration of each standard interfering gas in the interfering gas and its absorption coefficient in the second wavelength channel; calculate the gas concentration of the second detection gas based on Beer-Lambert's law; S4: Determine if there is a second detection gas whose gas concentration has not been calculated; if yes, obtain other interfering gases in the interfering gases corresponding to the remaining second detection gases whose gas concentration has not been calculated, and record the other interfering gases that are the same as the second detection gases whose gas concentration has been calculated as calibration interfering gases, and proceed to S2; if no, output the gas concentration of all second detection gases.

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