CN-122016655-A - Gas detection device and method

CN122016655ACN 122016655 ACN122016655 ACN 122016655ACN-122016655-A

Abstract

The application discloses a gas detection device, which comprises a gas tank, wherein the gas tank comprises a main cavity body extending along a first direction and a side arm communicated with the middle part of the main cavity body and extending along a second direction, a first laser of a TDLAS module couples a TDLAS laser beam into the main cavity body through an emitting optical fiber and propagates along the first direction to form an absorption optical path, the laser beam absorbed by gas is collected to a first detector through a receiving optical fiber, a second laser of a Raman module guides and focuses a Raman laser beam into a detection point in the main cavity body along the second direction through an excitation optical fiber, the detection point is positioned on a TDLAS laser beam optical path, and the Raman scattered light is collected to a second detector through a collecting optical fiber. The device can realize the concurrent detection and data complementation of TDLAS detection and Raman detection, and improves the gas detection precision and reliability.

Inventors

LIU LIFU
WANG ZHONGWEI
FENG YANAN
QU XIANGWEN
WU QIANG
YU ZHIWEI
ZHANG HAN
QU YING
CHEN JIANLONG
ZHAO YUGANG
CHEN DONG

Assignees

杭州泽天春来科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260415

Claims (10)

1. A gas detection apparatus, characterized in that the gas detection apparatus comprises: A gas cell comprising a main cavity extending in a first direction and a side arm in communication with a middle of the main cavity extending in a second direction spatially orthogonal to the first direction; the temperature acquisition module is used for acquiring the temperature of the gas in the gas tank; The pressure acquisition module is used for acquiring the gas pressure in the gas tank; The TDLAS module comprises a first laser and a first detector, wherein the first laser couples a TDLAS laser beam into the main cavity through an emitting optical fiber, so that the TDLAS laser beam propagates in the main cavity along the first direction to form an absorption light path, the TDLAS laser beam after gas absorption is collected by a receiving optical fiber and transmitted to the first detector, and the emitting optical fiber and the receiving optical fiber are positioned on the same side to form a transceiving integrated structure; The Raman module comprises a second laser and a second detector, the second laser guides a Raman laser beam into the main cavity along a second direction through the side arm through the excitation optical fiber, the Raman laser beam is focused on a detection point in the main cavity, the detection point is located on a TDLAS laser beam optical path, after being collected and converged by the lens group, the Raman scattered light is transmitted to the second detector through the collection optical fiber, and the excitation optical fiber and the collection optical fiber are directed at the detection point at an angle of 180 degrees back.
2. A gas detection method, wherein the gas detection method employs the gas detection apparatus according to claim 1, the gas detection method comprising: Performing data alignment on the TDLAS measurement data obtained by the TDLAS module and the Raman measurement data obtained by the Raman module; And carrying out mutual verification on the Raman measurement data and the TDLAS measurement data based on data alignment, and carrying out concentration inversion on the basis of the TDLAS measurement data after verification to obtain the concentration of the target gas in the gas to be detected.
3. The gas detection method according to claim 2, wherein the cross-checking of the raman measurement data and the TDLAS measurement data based on the data alignment comprises performing a background subtraction of interfering gas spectral line overlaps on the TDLAS measurement data based on the raman measurement data, comprising the steps of: Acquiring a synchronous time series data set, wherein the synchronous time series data set comprises a plurality of data points, any one data point comprises interference gas concentration corresponding to the same time stamp, an original mixed signal, temperature data and pressure data, the interference gas concentration is acquired through the Raman module, the original mixed signal is acquired through the TDLAS module, and the original mixed signal comprises absorption spectrum signals generated by target gas and interference gas; constructing a regression vector based on the interfering gas concentration, temperature data, and pressure data in the data points; Performing inner product on the regression vector and a preset parameter vector to obtain a predicted interference signal, wherein the parameter vector comprises response coefficients of a system to each interference element in the regression vector; And subtracting the predicted interference signal from the original mixed signal of the data points to obtain a corrected target gas effective signal.
4. A gas detection method according to claim 3, further comprising updating the parameter vector, comprising the steps of: Calculating a prediction error based on the original mixed signal and the predicted interference signal; The prediction error is weighted by a gain on the basis of the old parameter vector, so that the old parameter vector is updated to a new parameter vector, and the predicted interference signal is calculated on the basis of the new parameter vector.
5. The method for detecting gas according to claim 4, wherein, The gain is a gain vector constructed by adopting a recursive least square method according to a current regression vector, a covariance matrix and a preset forgetting factor, and is adaptively updated based on the current regression vector, wherein the covariance matrix is updated on line according to the updated gain vector.
6. The method for detecting a gas according to claim 4 or 5, wherein, And triggering updating of the parameter vector when the concentration change is larger than a preset concentration threshold according to the concentration of the interference gas measured by the Raman module.
7. The gas detection method according to claim 2, wherein the mutual verification of the raman measurement data and the TDLAS measurement data based on the data alignment further comprises a weighted calibration raman quantification model based on the TDLAS measurement data, comprising the steps of: Acquiring a synchronous time series data set, wherein the synchronous time series data set comprises a plurality of calibration data points, and any one of the calibration data points comprises Raman measurement data and TDLAS measurement data corresponding to the same time stamp; inverting to obtain a first quantity of TDLAS measurement gas component concentrations based on TDLAS measurement data in the calibration data points, calculating to obtain a second quantity of Raman measurement gas component concentrations by using a preset Raman quantitative model based on Raman measurement data in the calibration data points, and splicing the TDLAS measurement gas component concentrations and the Raman measurement gas component concentrations into a label vector, wherein the TDLAS measurement gas component types are different from the Raman measurement gas component types; Substituting the label vector into a preset weighted objective function, The weighted objective function reflects errors between the respective component concentrations in the tag vector and predicted component concentrations calculated based on the updated raman quantitative model, and the TDLAS measured gas component weight is greater than the raman measured gas component weight when the errors are calculated; And updating the Raman quantitative model according to a preset updating law by taking the minimum weighted objective function as a target.
8. The method for detecting gas according to claim 7, wherein, The update law is expressed by the following formula: ; ; In the formula, A predicted component concentration vector representing a raman quantitative model; representing a transpose of the regression coefficient matrix; a raman spectral feature vector representing raman measurement data; representing the bias vector; representing a regression coefficient matrix before updating; Representing the updated regression coefficient matrix; Representing a learning rate; Representing a weight matrix; Representing the tag vector.
9. The gas detection method of claim 7, further comprising performing a transfer calibration of a raman gas component concentration measured by a non-TDLAS with the TDLAS measured gas component concentration by: ; In the formula, And A coefficient of relationship representing a linear relationship between the j-th raman measurement gas component concentration and the i-th TDLAS measurement gas component concentration; A correction coefficient representing a raman residual; representing the concentration of the j-th gas component predicted by the Raman module; Indicating the concentration of the i-th gas component measured by the TDLAS module, and q indicating the number of gas component species measured by the TDLAS module.
10. The gas detection method according to claim 2, characterized in that the gas detection method further comprises: And analyzing the background gas component and the proportion in real time through the Raman measurement data, dynamically calculating the line intensity and line width parameters of the TDLAS absorption spectral line by combining the pressure and the temperature measured in real time, and correcting the proportion coefficient in the concentration inversion algorithm according to the line intensity and line width parameters.

Description

Gas detection device and method Technical Field The application relates to the technical field of gas detection, in particular to a gas detection device and a gas detection method. Background At present, although tunable semiconductor laser absorption spectroscopy (TDLAS) can realize high-sensitivity detection on specific gases, monitoring species are limited, and the detection is easy to be interfered under complex background gas, pressure and temperature changes, so that measurement errors are large. The Raman spectrum can identify multiple components at the same time, but has weak signal and low quantitative precision, and is difficult to be independently used for high-precision monitoring. In the prior art, a scheme combining the two systems mostly adopts a discrete air chamber or an optical path, so that the problems of complex system, large volume, signal crosstalk and the like exist, and an effective mechanism for carrying out real-time and dynamic environment compensation on TDLAS measurement by utilizing Raman information is lacking, so that the application in variable industrial sites is restricted. Disclosure of Invention The embodiment of the application provides a gas detection device and a gas detection method, and the device can improve the gas detection precision through dual-mode co-point detection. In a first aspect, the present application provides a gas detection apparatus comprising: the gas tank comprises a main cavity extending along a first direction and a side arm communicated with the middle part of the main cavity and extending along a second direction which is orthogonal to the space of the first direction; The temperature acquisition module is used for acquiring the gas temperature in the gas pool; The pressure acquisition module is used for acquiring the gas pressure in the gas pool; The TDLAS module comprises a first laser and a first detector, the first laser couples a TDLAS laser beam into the main cavity through an emitting optical fiber, so that the TDLAS laser beam propagates in the main cavity along a first direction to form an absorption light path, the TDLAS laser beam after gas absorption is collected by a receiving optical fiber and transmitted to the first detector, and the emitting optical fiber and the receiving optical fiber are positioned on the same side to form a transceiving integrated structure; The Raman module comprises a second laser and a second detector, wherein the second laser guides a Raman laser beam into the main cavity body along a second direction through the excitation optical fiber, the Raman laser beam is focused at a detection point in the main cavity body, the detection point is positioned on a TDLAS laser beam optical path, after the Raman scattered light is collected and converged by the lens group, the Raman scattered light is transmitted to the second detector through the collection optical fiber, and the excitation optical fiber and the collection optical fiber point to the detection point at an angle of 180 degrees back. In a second aspect, the present application also provides a gas detection method, the gas detection method employing the gas detection apparatus as in the first aspect, the gas detection method comprising: Carrying out data alignment on the TDLAS measurement data obtained by the TDLAS module and the Raman measurement data obtained by the Raman module; and carrying out mutual verification on the basis of the data-aligned Raman measurement data and the TDLAS measurement data, and carrying out concentration inversion on the basis of the verified TDLAS measurement data to obtain the concentration of the target gas in the gas to be detected. In one embodiment, the cross-checking based on the data-aligned raman measurement data and TDLAS measurement data comprises performing an interference gas line-overlapped background subtraction on the TDLAS measurement data based on the raman measurement data, comprising the steps of: Acquiring a synchronous time sequence data set, wherein the synchronous time sequence data set comprises a plurality of data points, any one data point comprises interference gas concentration, an original mixed signal, temperature data and pressure data corresponding to the same time stamp, the interference gas concentration is acquired through a Raman module, the original mixed signal is acquired through a TDLAS module, and the original mixed signal comprises absorption spectrum signals generated by target gas and the interference gas; Constructing a regression vector based on the interference gas concentration, the temperature data and the pressure data in the data points; Carrying out inner product on the regression vector and a preset parameter vector to obtain a predicted interference signal, wherein the parameter vector comprises response coefficients of the system to each interference element in the regression vector; And deducting the predicted interference signal from the original mixed signal of