Method and device for detecting flue gas

Abstract

The embodiment of the present application provides a flue gas detection method and device, the method comprises the following steps: obtaining real-time temperature and real-time pressure of flue gas; calculating initial gas absorption cross section according to the real-time temperature and the real-time pressure, the initial gas absorption cross section is used to indicate the absorption capacity of the gas contained in the flue gas to light under the temperature and pressure of the current measurement environment; correcting the initial gas absorption cross section based on a feedback adjustment algorithm to obtain a target gas absorption cross section; determining the composition and concentration of the gas contained in the flue gas according to the target gas absorption cross section. The flue gas detection method provided by the present application compensates the gas absorption cross section of the flue gas by measuring the temperature and pressure of the environment, and assists in compensating the absorption cross section change value by using a feedback adjustment algorithm, so that the concentration value calculated by the self-adaptive inversion algorithm can be corrected in real time, the influence of the temperature and pressure change in the measurement environment on the gas absorption cross section is further reduced, and the detection precision is improved.

Description

Technical Field

[0001] This invention relates to flue gas detection technology, and more particularly to a method and apparatus for detecting flue gas. Background Technology

[0002] With the development of industrial production, industrial production is closely related to flue gas emissions, making the detection of flue gas composition and concentration increasingly important. However, in actual measurement environments, flue gas temperature may vary depending on the dew point temperature of different gases or different reaction environments. Under different ambient temperatures and pressures, the absorption cross-section of gas molecules will also change. This means that changes in measurement temperature will affect the detection results, leading to significant errors in flue gas detection. Summary of the Invention

[0003] The present invention provides a method and apparatus for detecting flue gas, which solves the problem of large detection errors in the prior art.

[0004] In a first aspect, embodiments of the present invention provide a method for detecting flue gas, comprising:

[0005] Obtain the real-time temperature and pressure of the flue gas;

[0006] The initial gas absorption cross section is calculated based on the real-time temperature and the real-time pressure. The initial gas absorption cross section is used to indicate the ability of the gas contained in the flue gas to absorb light under the current temperature and pressure of the measurement environment.

[0007] The initial gas absorption cross section is corrected based on a feedback adjustment algorithm to obtain the target gas absorption cross section;

[0008] The composition and concentration of the gas contained in the flue gas are determined based on the target gas absorption cross section.

[0009] Optionally, calculating the initial gas absorption cross section based on the real-time temperature and the real-time pressure includes:

[0010] The temperature correction parameters of the absorption section are calculated based on the real-time temperature, and the pressure correction parameters of the absorption section are calculated based on the real-time pressure.

[0011] The target data is corrected based on the absorption cross-section temperature correction parameter and the absorption cross-section pressure correction parameter, wherein the target data is the gas absorption cross-section data under standard measurement conditions;

[0012] The initial gas absorption cross section is obtained based on the absorption cross section temperature correction parameter, the absorption cross section pressure correction parameter, and the corrected target data.

[0013] Optionally, after obtaining the initial gas absorption cross section, the method further includes:

[0014] The initial gas absorption cross section is inverted using the least squares method to obtain the first gas concentration;

[0015] The first gas concentration is corrected based on an adaptive algorithm to obtain a second gas concentration. The first gas concentration and the second gas concentration are preset values ​​of the gases contained in the flue gas. The accuracy of the second gas concentration is higher than that of the first gas concentration.

[0016] Optionally, the step of correcting the initial gas absorption cross section based on the feedback adjustment algorithm to obtain the target gas absorption cross section includes:

[0017] The initial gas absorption cross section is corrected based on the second gas concentration, the real-time temperature, and the real-time pressure to obtain the target gas absorption cross section.

[0018] Optionally, after obtaining the real-time temperature and pressure of the flue gas, the method further includes:

[0019] The flue gas is subjected to spectral analysis to obtain spectral information of the flue gas, and the spectral information includes at least one of the following: background spectrum, original spectrum and absorption spectrum;

[0020] The differential absorbance of the flue gas is determined based on the spectral information.

[0021] Optional,

[0022] The step of correcting the first gas concentration based on an adaptive algorithm to obtain the second gas concentration includes:

[0023] The first gas concentration is corrected based on an adaptive algorithm, and the concentration value of minimizing the error function in the gas absorption cross section is obtained by gradient descent method. The concentration value of minimizing the error function is used as the second gas concentration.

[0024] or

[0025] Alternatively, the gas absorption cross section can be solved by generating a second-order Hessian matrix using Newton's method to obtain the optimal concentration value, which is then used as the second gas concentration.

[0026] Secondly, embodiments of the present invention also provide a flue gas detection device, comprising: a sensing module, a measurement module, and an analysis module, wherein the analysis module is connected to the sensing module and the measurement module respectively;

[0027] The sensing module is used to acquire the real-time temperature and real-time pressure of the flue gas.

[0028] The measurement module is used to obtain the differential absorbance of the flue gas;

[0029] The analysis module is used to calculate an initial gas absorption cross section based on the real-time temperature and pressure of the flue gas. The initial gas absorption cross section is used to indicate the light absorption capacity of the gas contained in the flue gas under the current temperature and pressure of the measurement environment. The initial gas absorption cross section is corrected and compensated by a feedback adjustment algorithm to obtain a target gas absorption cross section. The composition and concentration of the gas contained in the flue gas are determined based on the difference between the target gas absorption cross section and the flue gas absorbance.

[0030] Optionally, the analysis module is also used to calculate the absorption cross-section temperature based on the real-time temperature, and to calculate the absorption cross-section pressure correction parameters based on the real-time pressure.

[0031] The target data is corrected based on the absorption cross-section temperature correction parameter and the absorption cross-section pressure correction parameter, wherein the target data is the gas absorption cross-section data under standard measurement conditions;

[0032] The initial gas absorption cross section is obtained based on the absorption cross section temperature correction parameter, the absorption cross section pressure correction parameter, and the corrected target data.

[0033] Optionally, the analysis module is further configured to invert the initial gas absorption cross section using the least squares method to obtain the first gas concentration;

[0034] The first gas concentration is corrected based on an adaptive algorithm to obtain a second gas concentration. The first gas concentration and the second gas concentration are preset values ​​of the gases contained in the flue gas. The accuracy of the second gas concentration is higher than that of the first gas concentration.

[0035] Optionally, the analysis module is further configured to correct the initial gas absorption cross section based on the second gas concentration, the real-time temperature, and the real-time pressure to obtain the target gas absorption cross section.

[0036] Optionally, the analysis module is also used for

[0037] The concentration of the first gas is corrected based on an adaptive algorithm, and the concentration value of the gas absorption cross section that minimizes the error function is obtained by gradient descent method. The concentration value of the minimized error function is then used as the concentration of the second gas.

[0038] or

[0039] Alternatively, the gas absorption cross section can be solved by generating a second-order Hessian matrix using Newton's method to obtain the optimal concentration value, which is then used as the second gas concentration.

[0040] Optionally, the sensing module includes a temperature sensor for acquiring the real-time temperature of the flue gas.

[0041] Optionally, the sensing module further includes a pressure sensor connected to the temperature sensor, which is used to acquire the real-time pressure of the flue gas.

[0042] Optionally, the measurement module includes a measurement light source, a gas sample cell, and a spectrometer. After the flue gas enters the gas sample cell, the spectrometer performs spectral analysis on the flue gas based on the measurement light source to obtain the spectral information of the flue gas.

[0043] Optionally, the device further includes a filtration module connected to the sensing module, the filtration module being used to filter the flue gas to remove impurities from the flue gas.

[0044] Optionally, the device further includes a display module connected to the analysis module, which is used to output the composition and concentration of the gas contained in the flue gas, as well as the real-time temperature and real-time pressure of the flue gas.

[0045] This invention provides a method and apparatus for detecting flue gas. The method includes: acquiring the real-time temperature and pressure of the flue gas; calculating an initial gas absorption cross section based on the real-time temperature and pressure, wherein the initial gas absorption cross section indicates the light absorption capacity of gases contained in the flue gas under the current measurement environment's temperature and pressure; correcting the initial gas absorption cross section based on a feedback adjustment algorithm to obtain a target gas absorption cross section; and determining the composition and concentration of gases contained in the flue gas based on the target gas absorption cross section. This invention provides a flue gas detection method that compensates for the gas absorption cross section of the flue gas by measuring ambient temperature and pressure, and uses a feedback adjustment algorithm to assist in compensating for changes in the absorption cross section. An adaptive inversion algorithm corrects the calculated concentration value in real time, further reducing the impact of temperature and pressure changes in the measurement environment on the gas absorption cross section and improving detection accuracy. Attached Figure Description

[0046] Figure 1 A schematic flowchart of a flue gas detection method provided in an embodiment of the present invention;

[0047] Figure 2 A schematic diagram of a flue gas detection device provided in an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of the structure of a flue gas detection device provided in an embodiment of the present invention;

[0049] Figure 4This is a flowchart of the calculation process of the analysis module in an embodiment of the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] Before discussing the exemplary embodiments in more detail, it should be noted that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the steps as sequential processes, many of these steps can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the steps can be rearranged. A process can be terminated when its operation is complete, but it may also have additional steps not included in the figures. A process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0052] Furthermore, the terms "first," "second," etc., may be used herein to describe various directions, actions, steps, or elements, but these directions, actions, steps, or elements are not limited by these terms. These terms are only used to distinguish a first direction, action, step, or element from another direction, action, step, or element. For example, without departing from the scope of this application, a first speed difference may be referred to as a second speed difference, and similarly, a second speed difference may be referred to as a first speed difference. Both the first speed difference and the second speed difference are speed differences, but they are not the same speed difference. The terms "first," "second," etc., should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0053] In this embodiment, differential optical absorption spectroscopy (DOAS) is generally used to identify gas molecules. The principle is to use the narrow-band absorption characteristics of the gas molecules to identify them and then deduce the concentration of the gas molecules based on the narrow-band absorption intensity. However, in current detection methods, the absorption cross-section of the gas changes due to temperature. Generally, as temperature increases, the peak value of the absorption cross-section decreases, the absorption peak width increases, and the absorption structure tends to be smoother, but the absorption lines remain evenly distributed and no peak shift occurs. To address this variation, a compensation algorithm can be added to compensate for the temperature-induced changes in the gas absorption cross-section when retrieving gas concentration, thereby improving accuracy. When pressure changes, the gas absorption cross-section also changes. Generally, as pressure increases, the absorption line width increases, and this also follows a certain pattern. Therefore, a compensation algorithm can be designed to eliminate the influence of pressure and temperature changes.

[0054] See Figure 1 , Figure 1 This is a schematic flowchart of a flue gas detection method provided in an embodiment of the present invention, as shown below. Figure 1 As shown in the figure, an embodiment of the present invention provides a method for detecting flue gas, comprising the following steps:

[0055] Step 110: Obtain the real-time temperature and pressure of the flue gas.

[0056] In this embodiment, the collected sample flue gas is filtered through a filter to remove dust and other large particulate impurities. Sensors are then used to obtain the real-time temperature and pressure of the sample flue gas. For example, a temperature sensor and a pressure sensor can be used to obtain the real-time temperature and pressure of the sample flue gas, respectively. The flue gas is then flowed into the DOAS measuring instrument. After the DOAS measuring instrument completes its detection, the flue gas flows out of the gas measurement system.

[0057] Step 120 calculates the initial gas absorption cross section based on the real-time temperature and the real-time pressure. The initial gas absorption cross section is used to indicate the ability of the gas contained in the flue gas to absorb light under the current temperature and pressure of the measurement environment.

[0058] In this embodiment, based on real-time flue gas temperature and pressure data, a correction coefficient for the gas absorption cross-section temperature and pressure is calculated, and this coefficient is used to correct the gas absorption cross-section data under the standard measurement environment.

[0059] Step 130: Correct the initial gas absorption cross section based on the feedback adjustment algorithm to obtain the target gas absorption cross section.

[0060] In this embodiment, the differential absorbance of the flue gas is calculated using data from the spectrometer and the original spectrum, and the initial gas absorption cross section is further corrected according to the feedback adjustment algorithm to finally obtain the target gas absorption cross section.

[0061] Step 140: Determine the composition and concentration of the gas contained in the flue gas based on the target gas absorption cross section.

[0062] In this embodiment, the final gas concentration can be determined by the differential absorbance calculated from the target gas absorption, as well as the real-time temperature and pressure values ​​of the flue gas obtained from temperature and pressure sensors.

[0063] Optionally, calculating the initial gas absorption cross section based on the real-time temperature and the real-time pressure includes:

[0064] The absorption section temperature is calculated based on the real-time temperature, and the absorption section pressure correction parameter is calculated based on the real-time pressure.

[0065] The target data is corrected based on the absorption cross-section temperature correction parameter and the absorption cross-section pressure correction parameter, wherein the target data is the gas absorption cross-section data under standard measurement conditions;

[0066] The initial gas absorption cross section is obtained based on the absorption cross section temperature correction parameter, the absorption cross section pressure correction parameter, and the corrected target data.

[0067] In this embodiment, since changes in ambient temperature and pressure cause changes in the gas absorption cross section, correction parameters for absorption cross section temperature and pressure are introduced to compensate for the changes in the gas absorption cross section caused by these factors, as shown below:

[0068]

[0069] Where σ(λ) is the gas differential absorption cross section parameter. For the temperature correction parameter of the absorption section, Let σ′(λ) be the pressure correction parameter for the absorption cross section, and σ′(λ) be the differential absorption cross section after compensation for temperature and pressure correction coefficients. The absorption cross section is related to the Lorenz widening and the Doppler widening, with the Lorenz widening mainly related to pressure and the Doppler widening mainly related to temperature, as described below:

[0070] Γ=Γ L +Γ D

[0071] Γ L =γ self P self +γ air Pair

[0072]

[0073] Where Γ is the measured half-width at half-maximum, Γ L For Lorenz half-width, Γ D For Doppler's half-width, γ self γ is the self-expansion coefficient. air Let be the air broadening factor, T be the temperature, and M be the molecular weight. The relationship between the broadening factor and temperature can be described as follows:

[0074]

[0075] Where n is the temperature correlation index, and T0 = 296 K. As shown in the above formula, temperature and pressure alter the gas absorption cross-section. In this embodiment, temperature and pressure correction coefficients are introduced to compensate for changes in the gas absorption cross-section, thereby improving the accuracy of gas concentration measurement.

[0076] Optionally, after obtaining the initial gas absorption cross section, the method further includes:

[0077] The first gas concentration is obtained by inverting the gas concentration using the least squares method, utilizing the differential absorbance and gas absorption cross section;

[0078] The first gas concentration is corrected based on an adaptive algorithm to obtain a second gas concentration. The first gas concentration and the second gas concentration are preset values ​​of the gases contained in the flue gas. The accuracy of the second gas concentration is higher than that of the first gas concentration.

[0079] In this embodiment, the relationship between the gas differential absorbance and the differential absorption cross section can be obtained according to the Lambert-Beer law as follows:

[0080]

[0081] Where OD(λ) is the differential absorbance of gas molecules at wavelength λ, σ i ′(λ) represents the differential absorption cross-section data of the i-th gas in the gas under test at wavelength λ after temperature and pressure correction, c i Let L be the concentration of the i-th gas in the gas to be measured, and L be the optical path length.

[0082] Assuming there are j types of gases to be measured, and the number of spectral data points is m (m > j), then the following formula holds:

[0083]

[0084] Since the number of equations m in the above equation is greater than the number of independent variables j, the above equation is an overdetermined equation, and the optimal solution can be calculated using the least squares method.

[0085]

[0086] Minimizing e yields the gas concentration c closest to the true value in the inversion band. i That is, the concentration of the first gas.

[0087] Optional,

[0088] The step of correcting the first gas concentration based on an adaptive algorithm to obtain the second gas concentration includes:

[0089] The first gas concentration is corrected based on an adaptive algorithm, and the concentration value of minimizing the error function in the gas absorption cross section is obtained by gradient descent method. The concentration value of minimizing the error function is used as the second gas concentration.

[0090] or

[0091] Alternatively, the gas absorption cross section can be solved by generating a second-order Hessian matrix using Newton's method to obtain the optimal concentration value, which is then used as the second gas concentration.

[0092] In this embodiment, an adaptive algorithm is employed to correct the concentration value obtained in step three using the least squares method, further improving its accuracy. The method can employ, for example, gradient descent, using gradient information to find the concentration value that minimizes the error function, which is the corrected concentration value; alternatively, Newton's method can be used, solving for the optimal concentration value using the inverse of the second-order Hessian matrix. By using an adaptive algorithm to correct the concentration value, the addition of a feedback loop and correction coefficient jointly compensates for changes in the absorption cross-section, further improving the accuracy of gas concentration measurement. Furthermore, the measurement system can still provide good detection results even when facing real-time and continuous changes in ambient temperature and pressure.

[0093] Specifically, in this embodiment, the gradient descent method is illustrated using the following example. In this example, a unique variable-scale gradient descent method is used to correct the concentration value. The optimization problem is as follows:

[0094] Where c i ∈[a i ,b i ] represents the set range of concentration values. This range can be set according to the actual situation, or it can be set according to the concentration value obtained in the previous step. Let the initial value C(0) be the concentration value obtained by the least squares method in the previous step, C * =C(0), k=0, find the partial derivative F′1=(f′1,f′2,…,f′j ), obtain

[0095]

[0096] where δ 0i is the step size. Calculate f[C(1)]. If f[C(1)] < f[C(0)], then update C * = C(1). In subsequent iterations, the step size is expressed as:

[0097]

[0098] where h is the number of iterations, m is a positive integer that can be determined according to the optimization objective function, and c 0i is the concentration of the i-th gas obtained by the least squares method in the previous step. In this method, 0 < α h < 1, and it decreases as the number of iterations h increases. For this example, an original parameter is introduced with the concentration value obtained in the previous step as the reference. This parameter also decreases as the number of iterations h increases, and when the measured concentration value is large, the step size is also longer, and when the measured concentration value is small, the step size also becomes shorter, meaning that the selection of the step size is adaptive and follows the gas concentration value. At the beginning of the search, it is hoped that the step size δ hi varies greatly to quickly search for the optimal point. As the number of iterations increases and gradually approaches the optimal point, it is hoped that the step size δ hi varies less to accurately search for the optimal solution; and if the measured gas concentration value is large, it means that the error range may also be large, so a larger step size is required to accelerate the search speed. On the contrary, if the measured gas concentration value is small, it means that the error range is not too large, so a smaller step size is required for accurate search. Therefore, by introducing this parameter, this purpose can be achieved.

[0099] [[ID=3​​​​​​​​​​​​​​​​At this point, the concentration value corrected by the adaptive algorithm is obtained, which is the second gas concentration. This concentration is then used to correct the gas absorption cross section σ through a feedback adjustment algorithm. i (λ) gives the gas absorption cross section σ′ after feedback correction. i (λ)

[0102]

[0103] Where P is pressure, R is Boltzmann's constant, and T is thermodynamic temperature. The second gas concentration is used. The gas absorption cross-section is corrected using a feedback loop in conjunction with temperature and absorption cross-section pressure correction parameters.

[0104]

[0105] This data represents the gas absorption cross-section after compensation by feedback and correction parameters for absorption cross-section temperature and pressure. The feedback mechanism, along with temperature and pressure corrections, compensates for changes in the absorption cross-section using a weighted method, with A1 and A2 representing their respective weights. These values ​​can be adjusted based on measurement conditions during practical applications. Over time, the system's measurement accuracy will increase, and it can adapt to real-time and continuous changes in ambient temperature and pressure, constantly correcting the gas absorption cross-section parameters and adjusting the measured concentration to ensure system accuracy.

[0106] Optionally, the step of correcting the initial gas absorption cross section based on the feedback adjustment algorithm to obtain the target gas absorption cross section includes:

[0107] The initial gas absorption cross section is corrected based on the second gas concentration, the real-time temperature, and the real-time pressure to obtain the target gas absorption cross section.

[0108] Optionally, after obtaining the real-time temperature and pressure of the flue gas, the method further includes:

[0109] The flue gas is subjected to spectral analysis to obtain spectral information of the flue gas, and the spectral information includes at least one of the following: background spectrum, original spectrum and absorption spectrum;

[0110] The differential absorbance of the flue gas is determined based on the spectral information.

[0111] In this embodiment, the spectrometer can obtain the background spectrum I. b Given the original spectrum I0(λ) and the absorption spectrum I(λ), the differential absorbance can be calculated as follows:

[0112]

[0113] This invention provides a method and apparatus for detecting flue gas. The method includes: acquiring the real-time temperature and pressure of the flue gas; calculating an initial gas absorption cross section based on the real-time temperature and pressure, wherein the initial gas absorption cross section indicates the light absorption capacity of gases contained in the flue gas under the current measurement environment's temperature and pressure; correcting the initial gas absorption cross section based on a feedback adjustment algorithm to obtain a target gas absorption cross section; and determining the composition and concentration of gases contained in the flue gas based on the target gas absorption cross section. This invention provides a flue gas detection method that compensates for the gas absorption cross section of the flue gas by measuring ambient temperature and pressure, and uses a feedback adjustment algorithm to assist in compensating for changes in the absorption cross section. An adaptive inversion algorithm corrects the calculated concentration value in real time, further reducing the impact of temperature and pressure changes in the measurement environment on the gas absorption cross section and improving detection accuracy.

[0114] In another embodiment, see Figure 2 , Figure 2 A schematic diagram of a flue gas detection device provided in an embodiment of the present invention includes: a sensing module, a measurement module, and an analysis module, wherein the analysis module is connected to the sensing module and the measurement module respectively;

[0115] The sensing module is used to acquire the real-time temperature and real-time pressure of the flue gas.

[0116] The measurement module is used to obtain the differential absorbance of the flue gas;

[0117] The analysis module is used to calculate an initial gas absorption cross section based on the real-time temperature and pressure of the flue gas. The initial gas absorption cross section is used to indicate the light absorption capacity of the gas contained in the flue gas under the current temperature and pressure of the measurement environment. The initial gas absorption cross section is corrected and compensated by a feedback adjustment algorithm to obtain a target gas absorption cross section. The composition and concentration of the gas contained in the flue gas are determined based on the difference between the target gas absorption cross section and the flue gas absorbance.

[0118] Optionally, the analysis module is also used to calculate the absorption cross-section temperature based on the real-time temperature, and to calculate the absorption cross-section pressure correction parameters based on the real-time pressure.

[0119] The target data is corrected based on the absorption cross-section temperature correction parameter and the absorption cross-section pressure correction parameter, wherein the target data is the gas absorption cross-section data under standard measurement conditions;

[0120] The initial gas absorption cross section is obtained based on the absorption cross section temperature correction parameter, the absorption cross section pressure correction parameter, and the corrected target data.

[0121] Optionally, the analysis module is further configured to invert the initial gas absorption cross section using the least squares method to obtain the first gas concentration;

[0122] The first gas concentration is corrected based on an adaptive algorithm to obtain a second gas concentration. The first gas concentration and the second gas concentration are preset values ​​of the gases contained in the flue gas. The accuracy of the second gas concentration is higher than that of the first gas concentration.

[0123] Optionally, the analysis module is further configured to correct the first gas concentration based on an adaptive algorithm, and obtain the concentration value of minimizing the error function in the gas absorption cross section by gradient descent method, and use the concentration value of minimizing the error function as the second gas concentration;

[0124] or

[0125] Alternatively, the gas absorption cross section can be solved by generating a second-order Hessian matrix using Newton's method to obtain the optimal concentration value, which is then used as the second gas concentration.

[0126] Optionally, the sensing module includes a temperature sensor for acquiring the real-time temperature of the flue gas.

[0127] Optionally, the sensing module further includes a pressure sensor connected to the temperature sensor, which is used to acquire the real-time pressure of the flue gas.

[0128] Optionally, the measurement module includes a measurement light source, a gas sample cell, and a spectrometer. After the flue gas enters the gas sample cell, the spectrometer performs spectral analysis on the flue gas based on the measurement light source to obtain the spectral information of the flue gas.

[0129] Optionally, the device further includes a filtration module connected to the sensing module, the filtration module being used to filter the flue gas to remove impurities from the flue gas.

[0130] Optionally, the device further includes a display module connected to the analysis module, which is used to output the composition and concentration of the gas contained in the flue gas, as well as the real-time temperature and real-time pressure of the flue gas.

[0131] In this embodiment, refer to Figure 3 , Figure 3 This is a schematic diagram of the structure of the flue gas detection device in an embodiment of the present invention, as shown below. Figure 3As shown, the incoming flue gas first flows through a filter to remove dust and other large particulate impurities. Then it flows through a temperature sensor to obtain real-time temperature information of the incoming flue gas. Next, it flows through a pressure sensor to obtain real-time pressure information of the incoming flue gas. Finally, it flows through the DOAS measurement unit, passes through the gas pool in the measurement unit, and then flows out of the gas measurement system.

[0132] The gas flows through the temperature sensor, and the real-time flue gas temperature data is transmitted to the analysis unit; the gas flows through the pressure sensor, and the real-time flue gas pressure data is transmitted to the analysis unit; in the DOAS measurement unit, the light emitted by the light source is transmitted to the gas cell, and after being scattered and absorbed by the flue gas in the gas cell, it is transmitted to the spectrometer through the optical fiber to obtain spectral data, which is then transmitted to the analysis unit.

[0133] See Figure 4 , Figure 4 This is a schematic diagram of the analysis module in an embodiment of the present invention. Specifically, the data obtainable from the spectrometer includes the background spectrum of the light source, the original spectrum, and the absorption spectrum obtained after scattering and absorption by the flue gas. The differential absorbance of the gas in the flue gas can be calculated based on this spectral information. Based on the real-time temperature and pressure data of the flue gas obtained from temperature and pressure sensors, the temperature and pressure correction parameters of the absorption cross-section are calculated, and the differential absorption cross-section of the gas is corrected and compensated. The concentration of the gas to be measured is inverted using the least squares method. An adaptive algorithm is used to correct the concentration value obtained in the previous step, resulting in a more accurate concentration value. The concentration value from the previous step is fed back to the position of the gas differential absorption cross-section, and the auxiliary correction parameters jointly compensate for the change in the gas differential absorption cross-section. The feedback mechanism is used to adjust the differential absorption cross-section, improving the concentration measurement accuracy. Based on real-time temperature and pressure data of flue gas, temperature and pressure correction coefficients for the gas absorption cross section are obtained, and these coefficients are used to correct the gas differential absorption cross section data. On the other hand, differential absorbance is calculated based on spectrometer data and raw spectral data. Gas concentration is then inverted using differential absorbance and gas differential absorption cross section to obtain a preliminary concentration value. This preliminary concentration value is then further corrected using an adaptive correction algorithm to obtain the final gas concentration. The concentration information obtained at this point is fed back to the gas differential absorption cross section correction position through a feedback loop. Together with the correction coefficient, it compensates for the impact of temperature and pressure changes on the gas absorption cross section, and this process is repeated over time.

[0134] The display screen shows the final gas concentration value obtained by the analysis unit, as well as the real-time temperature and pressure values ​​of the flue gas obtained by the temperature and pressure sensors.

[0135] This invention provides a flue gas detection device, comprising: a sensing module, a measurement module, and an analysis module. The analysis module is connected to both the sensing module and the measurement module. The sensing module acquires the real-time temperature and pressure of the flue gas. The measurement module acquires the differential absorbance of the flue gas. The analysis module calculates an initial gas absorption cross section based on the real-time temperature and pressure of the flue gas. This initial gas absorption cross section indicates the light absorption capacity of the gas contained in the flue gas under the current temperature and pressure of the measurement environment. A feedback adjustment algorithm is used to correct and compensate the initial gas absorption cross section to obtain a target gas absorption cross section. The composition and concentration of the gas contained in the flue gas are determined based on the target gas absorption cross section and the differential absorbance of the flue gas. This invention provides a flue gas detection method that compensates for the gas absorption cross section of the flue gas by measuring the ambient temperature and pressure, and uses a feedback adjustment algorithm to assist in compensating for changes in the absorption cross section. An adaptive inversion algorithm corrects the calculated concentration value in real time, further reducing the impact of temperature and pressure changes in the measurement environment on the gas absorption cross section and improving detection accuracy.

[0136] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method of detecting flue gas, characterized by, The method comprises the following steps: acquiring real-time temperature and real-time pressure of flue gas; calculating an initial gas absorption cross section according to the real-time temperature and the real-time pressure, the initial gas absorption cross section being used to indicate the absorption capacity of a gas contained in the flue gas to light under the temperature and pressure of the current measurement environment, the calculation of the initial gas absorption cross section according to the real-time temperature and the real-time pressure comprising: calculating an absorption cross section temperature correction parameter according to the real-time temperature, and calculating an absorption cross section pressure correction parameter according to the real-time pressure; correcting target data according to the absorption cross section temperature correction parameter and the absorption cross section pressure correction parameter, the target data being gas absorption cross section data under a standard measurement environment; obtaining an initial gas absorption cross section according to the absorption cross section temperature correction parameter, the absorption cross section pressure correction parameter and the corrected target data, the absorption cross section temperature correction parameter and the absorption cross section pressure correction parameter being represented by the following formula: wherein σ(λ) is a gas differential absorption cross-section parameter, is an absorption cross-section temperature correction parameter, is an absorption cross-section pressure correction parameter, and σ'(λ) is a differential absorption cross-section compensated by temperature and pressure correction factors. inverting the initial gas absorption cross section by a least square method to obtain a first gas concentration; correcting the first gas concentration based on an adaptive algorithm to obtain a second gas concentration, the first gas concentration and the second gas concentration being preset values of the gas contained in the flue gas, the accuracy of the second gas concentration being higher than that of the first gas concentration; correcting the initial gas absorption cross section based on a feedback regulation algorithm to obtain a target gas absorption cross section, the correction of the initial gas absorption cross section based on the feedback regulation algorithm to obtain the target gas absorption cross section comprising: correcting the initial gas absorption cross section according to the second gas concentration, the real-time temperature and the real-time pressure to obtain the target gas absorption cross section; The feedback-corrected gas absorption cross section σ i ′(λ) is expressed by the following equation: where P is the pressure, R is the Boltzmann constant, and T is the thermodynamic temperature, is the second gas concentration; correcting the gas absorption cross section by a feedback link together with the temperature and the absorption cross section pressure correction parameter, the correction of the gas absorption cross section by the feedback link together with the temperature and the absorption cross section pressure correction parameter being represented by the following formula: wherein, is the gas absorption cross-section data after jointly compensating by the feedback and absorption cross-section temperature, absorption cross-section pressure correction parameters, wherein the weighted method is adopted for jointly compensating the absorption cross-section variation by the feedback link and temperature and pressure, A1 and A2 are respective weighting values, which can be adjusted according to the measurement in the actual application process; determining the composition and the concentration of the gas contained in the flue gas according to the target gas absorption cross section.

2. The method of claim 1, wherein, After the acquisition of the real-time temperature and the real-time pressure of the flue gas, the method further comprises the following steps: performing spectral analysis on the flue gas to obtain spectral information of the flue gas, the spectral information comprising at least one of the following: background spectrum, original spectrum and absorption spectrum; determining the differential absorption of the flue gas based on the spectral information.

3. The method of claim 1, wherein, The correction of the first gas concentration based on the adaptive algorithm to obtain the second gas concentration comprises the following steps: correcting the first gas concentration based on the adaptive algorithm, and obtaining a concentration value of a minimized error function in the gas absorption cross section by a gradient descent method, the concentration value of the minimized error function being taken as the second gas concentration; or or generating a second-order Hessian matrix by a Newton method to solve the gas absorption cross section to obtain an optimal concentration value, the optimal concentration value being taken as the second gas concentration.

4. A detection device for flue gas, applied to the detection method for flue gas according to any one of claims 1-3, characterized in that, The method comprises the following steps: a sensing module, a measurement module and an analysis module, the analysis module being connected with the sensing module and the measurement module respectively; the sensing module is used to acquire real-time temperature and real-time pressure of flue gas; the measurement module is used to acquire differential absorption of flue gas; The analysis module is configured to calculate an initial gas absorption cross section according to the real-time temperature and the real-time pressure of the flue gas, the initial gas absorption cross section is used to indicate the absorption capacity of the gas contained in the flue gas to light under the temperature and pressure of the current measurement environment, the initial gas absorption cross section is corrected and compensated by a feedback adjustment algorithm to obtain a target gas absorption cross section, and the composition and concentration of the gas contained in the flue gas are determined according to the target gas absorption cross section and the differential absorption of the flue gas. The analysis module is further configured to calculate an absorption cross section temperature according to the real-time temperature and an absorption cross section pressure correction parameter according to the real-time pressure, correct target data according to the absorption cross section temperature correction parameter and the absorption cross section pressure correction parameter, the target data being gas absorption cross section data under a standard measurement environment, and obtain an initial gas absorption cross section according to the absorption cross section temperature correction parameter, the absorption cross section pressure correction parameter and the corrected target data.

5. The apparatus of claim 4, wherein, The analysis module is further configured to inverse the initial gas absorption cross section by a least square method to obtain a first gas concentration. The first gas concentration is corrected based on an adaptive algorithm to obtain a second gas concentration, the first gas concentration and the second gas concentration being preset values of the gas contained in the flue gas, and the accuracy of the second gas concentration being higher than that of the first gas concentration.

6. The apparatus of claim 5, wherein, The analysis module is further configured to correct the initial gas absorption cross section according to the second gas concentration, the real-time temperature and the real-time pressure to obtain a target gas absorption cross section.

7. The apparatus of claim 4, wherein The analysis module is further configured to correct the first gas concentration based on an adaptive algorithm and obtain a concentration value of a minimized error function of the gas absorption cross section by a gradient descent method, and take the concentration value of the minimized error function as the second gas concentration. Or Or solve the gas absorption cross section by a Newton method to generate a second-order Hessian matrix to obtain an optimal concentration value, and take the optimal concentration value as the second gas concentration.

8. The apparatus of claim 4, wherein, The sensing module includes a temperature sensor configured to obtain the real-time temperature of the flue gas.

9. The apparatus of claim 8, wherein, The sensing module further includes an air pressure sensor connected with the temperature sensor, and the air pressure sensor is configured to obtain the real-time pressure of the flue gas.

10. The apparatus of claim 4, wherein, The measurement module includes a measurement light source, a gas sample cell and a spectrometer, the spectrometer is configured to perform spectral analysis on the flue gas based on the measurement light source to obtain spectral information of the flue gas after the flue gas enters the gas sample cell.

11. The apparatus of claim 4, wherein, The device further includes a filtering module connected with the sensing module, and the filtering module is configured to filter the flue gas to exclude impurities in the flue gas.

12. The apparatus of claim 4, wherein, The device further includes a display module connected with the analysis module, and the display module is configured to output the composition and concentration of the gas contained in the flue gas and the real-time temperature and real-time pressure of the flue gas.

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