Gas leakage detection system based on intermediate infrared laser

Abstract

The invention discloses a fuel gas leakage detection system based on mid-infrared laser, relates to the technical field of fuel gas detection, and aims to solve the problems that a large-area region is difficult to cover quickly and only close-range detection can be carried out in an existing laser fuel gas leakage detection method. The gas leakage detection system comprises a laser emission module, an infrared imaging detector module and a data processing module, the laser emission module is used for emitting an intermediate infrared laser beam to a to-be-detected area; the infrared imaging detector module is used for collecting an infrared spectrum signal of the to-be-detected area in real time; the infrared spectrum transmitting module is used for transmitting the infrared spectrum signal to the data processing module; and the data processing module is used for processing the received infrared spectrum signal to obtain a gas leakage detection result of the to-be-detected area. The method is suitable for detecting gas leakage in a natural gas pipeline and a liquefied petroleum gas storage tank area.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, and more specifically to the field of image-based gas detection technology. Background Technology

[0002] Gas leaks pose a serious safety hazard during the production, storage, transportation, and use of natural gas. They can cause explosions, fires, and poisoning, posing a significant threat to life, property, and the environment. Therefore, gas leak detection technology is of great importance.

[0003] Laser gas leak detection is a conventional gas leak detection technique that primarily utilizes the absorption properties of laser light by gas molecules. It involves drawing gas from the area to be detected into the instrument to determine the location and concentration of the leak. However, this method has several drawbacks, specifically: One drawback is that it is difficult to quickly cover a large area, and each time only a small amount of inhaled gas can be analyzed, resulting in low detection efficiency.

[0004] The second drawback is that it can only perform short-range detection, and cannot detect gas leaks in hard-to-reach or dangerous areas, thus failing to meet the need for efficient, remote, and large-area monitoring of gas leaks. In summary, existing laser gas leak detection methods have limitations in rapidly covering large areas and can only perform short-range detection. Summary of the Invention

[0005] This invention specifically addresses the limitations of existing laser gas leak detection methods, such as difficulty in quickly covering large areas and limitation to short-range detection. This invention provides the following solution: Option 1: A gas leak detection system, comprising a laser emitting module, an infrared imaging detector module, and a data processing module; The laser emitting module is used to emit a mid-infrared laser beam toward the area to be detected; The infrared imaging detector module is used to acquire the infrared spectral signal of the area to be detected in real time; and to send the infrared spectral signal to the data processing module. The data processing module is used to process the received infrared spectral signal to obtain the gas leak detection result of the area to be detected.

[0006] Furthermore, in one embodiment of the present invention, the infrared imaging detector module includes an imaging optical system and an infrared detector array; The imaging optical system is used to acquire the light signal of the area to be detected in real time and send it to the infrared detector array. The infrared detector array is used to perform photoelectric conversion on the optical signal to obtain an infrared spectral signal.

[0007] Furthermore, in one embodiment of the present invention, the mid-infrared laser beam is a laser beam with a wavelength of 3.3μm, 3.4μm or 3.5μm, or a laser beam consisting of a combination of the above-mentioned wavelengths or a combination of wavelength ranges.

[0008] Furthermore, in one embodiment of the present invention, the multiple band combinations are combinations of a 3.3μm band with any other one or more other bands.

[0009] Furthermore, in one embodiment of the present invention, the gas leak detection system further includes a data display output module; The data processing module is used to send the obtained gas leak detection results to the data display module; The data display output module is used to display the received gas leak detection results.

[0010] Furthermore, in one embodiment of the present invention, the gas leak detection result is one or more of the following: the type of leaked gas, the location of the leak, or the concentration of the leak.

[0011] Furthermore, in one embodiment of the present invention, the data processing module includes the following units: The noise cancellation unit is used to filter out stray light signals in the received infrared spectral signal to obtain a net spectral signal. ; Relative absorption intensity Acquisition unit for background spectrum under leak-free conditions The net spectral signal pass

[0012] Obtaining relative absorption strength ; The leaked gas type acquisition unit is used to determine the relative absorption intensity through correlation analysis. The similarity value is calculated with the standard spectra of each gas in the standard gas spectrum database. If the similarity value is >95%, it is confirmed that there is a leak of the gas type corresponding to the standard spectrum in the area to be detected.

[0013] Furthermore, in one embodiment of the present invention, the data processing module further includes a leakage location acquisition unit, used to determine the leakage location based on the relative absorption intensity of all similarity values ​​> 95%. Obtain the corresponding net spectral signal in the on-spectrum. The location in the detection area is identified as an area with abnormal concentration, which is the location of the gas leak.

[0014] Furthermore, in one embodiment of the present invention, the data processing module further includes a leaked gas concentration acquisition unit, used to, based on the acquired leaked gas type, through...

[0015] Obtain the corresponding leaked gas concentration ,in The intensity of resonance fluorescence; This is the calibration coefficient.

[0016] The gas leak detection system and method described in this invention are based on mid-infrared laser, effectively alleviating the problems of existing laser gas leak detection methods, such as difficulty in quickly covering large areas and limitation to short-range detection. This enables gas leak detection with a large detection range and over long distances. Specific beneficial effects include: The gas leak detection system described in this invention is used to detect gas leaks in an area to be inspected. The difference between this system and existing technologies lies in the limitations of existing technologies, such as difficulty in quickly covering large areas and limitation to short-range detection. To address these issues, this invention constructs a gas leak detection system comprising a laser emission module, an infrared imaging detector module, and a data processing module. It eliminates the need to draw gas into the instrument for detection, rapidly scanning large areas via laser telemetry, significantly shortening detection time and improving efficiency. Furthermore, it enables remote detection of inaccessible or hazardous areas, overcoming the distance limitations of traditional detection methods and allowing for the timely detection of potential gas leak hazards.

[0017] The method described in this invention is applicable to the detection of gas leaks in natural gas pipelines and liquefied petroleum gas storage tank areas. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the gas leak detection system described in Embodiment 1.

[0019] Figure label: Laser emission module 1; Infrared imaging detector module 2; Data processing module 3; Data display output module 4; Gas leak area 5. Detailed Implementation

[0020] Various embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. The embodiments described with reference to the drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] Implementation Method 1: The gas leak detection system described in this implementation method, such as... Figure 1 As shown, it includes a laser emission module, an infrared imaging detector module, and a data processing module; The laser emitting module is used to emit a mid-infrared laser beam toward the area to be detected; The infrared imaging detector module is used to acquire the infrared spectral signal of the area to be detected in real time; and to send the infrared spectral signal to the data processing module. The data processing module is used to process the received infrared spectral signal to obtain the gas leak detection result of the area to be detected.

[0022] In this embodiment, the infrared imaging detector module includes an imaging optical system and an infrared detector array; The imaging optical system is used to acquire the light signal of the area to be detected in real time and send it to the infrared detector array. The infrared detector array is used to perform photoelectric conversion on the optical signal to obtain an infrared spectral signal.

[0023] In this embodiment, the laser emission module preferably uses a quantum cascade laser (QCL), which can stably output a laser beam with the required wavelength and power, and precisely guide the laser to the area to be detected through collimation and focusing optical elements.

[0024] In this embodiment, the data processing module obtains the detection result based on the contrast difference in optical properties between the gas molecules and the surrounding air in the received infrared spectral signal.

[0025] The contrast difference is due to the fact that the gas molecules have a significant absorption band in the mid-infrared region (typically 2–20 μm). By absorbing the energy of the mid-infrared laser, they transition to a higher energy level, thus creating a contrast difference with the surrounding air.

[0026] The gas molecules exhibit distinct absorption bands in the mid-infrared region. Specifically, CH4 absorbs mid-infrared laser beams at wavelengths of 3.31 μm and 7.66 μm; CO absorbs at 4.65 μm; CO2 absorbs at 4.26 μm; H2S absorbs mid-infrared laser beams at 7.6–8.0 μm; and propane / butane absorbs at 3.3–3.5 μm.

[0027] In this embodiment, the data processing module obtains the detection result based on the received infrared spectral signal. The detection result includes, but is not limited to, the leak location or leak concentration. The data processing module stores the detection result. The data processing module also sends the detection result to the data display module.

[0028] The gas leak detection system described in this embodiment is a long-range, highly efficient, and convenient gas leak detection technology that effectively alleviates the problems of existing laser gas leak detection methods, such as difficulty in quickly covering large areas and limitation to short-range detection. The gas leak detection system described in this embodiment includes a laser emission module, an infrared imaging detector module, and a data processing module. It rapidly scans and detects large areas using laser telemetry, greatly shortening detection time and improving detection efficiency. Furthermore, it can remotely detect inaccessible or dangerous areas, breaking through the distance limitations of traditional detection methods and enabling timely detection of potential gas leak hazards.

[0029] This embodiment provides Example 1, which applies the gas leak detection system to a natural gas pipeline area for gas leak detection.

[0030] The laser emitting module emits a mid-infrared laser beam in the 7.6μm band to scan the ground area above the underground natural gas pipeline. When the laser beam passes over an area with a natural gas leak, the leaking methane molecules absorb the laser energy, creating a significant contrast with the surrounding air. The infrared imaging module captures this contrast difference, generates an infrared spectral signal, and transmits it to the data processing module. The data processing module analyzes the image, calculates the natural gas leak rate in the area based on the contrast, and clearly displays the specific coordinates and leak rate of the leak location on a display screen. Based on this information, inspection personnel can quickly locate the leak and take appropriate repair measures, preventing potential safety accidents.

[0031] This embodiment provides Example 2, which applies the gas leak detection system to a liquefied petroleum gas storage tank area for gas leak detection.

[0032] Since liquefied petroleum gas (LPG) mainly consists of propane and butane, the laser emission module simultaneously emits mid-infrared laser beams in the 3.3-3.4 μm (for propane) and 3.3-3.5 μm (for butane) bands to comprehensively scan the tank area. During the scan, the infrared imaging module detected abnormal contrast in one area. The data processing module analyzed the received infrared spectral signals, determining that there was a leak of both propane and butane in that area, and calculated the leakage rates for propane and butane respectively. Through further data processing, the leak source was located at a valve connection point of a certain tank. Based on the detection results, the inspection personnel quickly repaired the leaking valve, effectively ensuring the safe operation of the tank area.

[0033] Implementation Method 2: This implementation method further defines the gas leak detection system described in Implementation Method 1. In this implementation method, the mid-infrared laser beam is a laser beam with a wavelength of 3.3μm, 3.4μm, or 3.5μm, or a laser beam consisting of a combination of multiple wavelengths or a combination of wavelength ranges.

[0034] In this embodiment, if the main component of the gas in the area to be detected is methane, the preferred wavelength of the mid-infrared laser beam is 3.3 μm, which can balance sensitivity and anti-interference. In this embodiment, if the main component of the gas in the detection area is propane, then the preferred wavelength of the mid-infrared laser beam is 3.4 μm.

[0035] In this embodiment, if the main component of the gas in the detection area is butane, the preferred wavelength of the mid-infrared laser beam is 3.5 μm.

[0036] In this embodiment, a mid-infrared laser beam with a wavelength of 3.4 μm is emitted into the area to be detected to detect total alkane, which can achieve rapid screening.

[0037] In this embodiment, if the main component of the gas in the detection area is liquefied petroleum gas, it is preferable to use the mid-infrared laser beam with a wavelength range of 3.3-3.4μm and 3.3-3.5μm as the laser combination, which can identify propane and butane respectively, effectively avoiding misjudgment that may occur when detecting with a single wavelength; the main components of the liquefied petroleum gas are propane and butane.

[0038] This embodiment further defines the band of the mid-infrared laser beam and provides an example of the band scheme for the mid-infrared laser beam. This method provides a variety of selectable mid-infrared laser beam bands. By selecting a mid-infrared laser with a high absorption coefficient for different gas components, the contrast difference between gas molecules and the surrounding air in the area to be detected can be accurately obtained, thereby improving the accuracy of detection.

[0039] Implementation Method 3: This implementation method further defines the gas leak detection system described in Implementation Method 3. In this implementation method, the multiple band combinations are combinations of a 3.3μm band with any one or more other bands.

[0040] This embodiment further defines the mid-infrared laser beam and provides an example of a mid-infrared laser beam scheme. This method combines a 3.3μm mid-infrared laser beam with any other mid-infrared laser beam of one or more other wavelengths as a laser combination, which can perform dual verification and is suitable for detection areas with high precision requirements.

[0041] Implementation Method 4: The gas leak detection method described in this implementation method is based on the following system, which includes a laser emission module, an infrared imaging detector module, and a data processing module; The laser emitting module is used to emit a mid-infrared laser beam toward the area to be detected; The infrared imaging detector module is used to acquire the infrared spectral signal of the area to be detected in real time; and to send the infrared spectral signal to the data processing module. The data processing module internally stores a computer program that implements the following method: Phase 1: Eliminating noise interference; Step S1: Filter out stray light signals from the obtained infrared spectral signal to obtain the net spectral signal. ; Step S2, based on the background spectrum under leak-free conditions The net spectral signal pass

[0042] Obtaining relative absorption strength ; Phase Two: Obtain the type of leaked gas in the area to be detected; Step S3, the relative absorption intensity is determined by correlation analysis. The similarity value is calculated with the standard spectra of each gas in the standard gas spectrum database. If the similarity value is >95%, the type of leaked gas in the area to be detected is obtained. Phase 3: Using a multi-pixel detector to locate the leak; Step S4, based on the obtained relative absorption intensity By using a multi-pixel array to identify areas of abnormal concentration in the area to be detected, the location of the leak can be obtained.

[0043] Phase Four: Obtain the leakage concentration; Step S5, based on the obtained type of leaked gas, through

[0044] Obtain the corresponding leaked gas concentration ,in The intensity of resonance fluorescence; This is the calibration coefficient.

[0045] In this embodiment, the similarity value in stage two is preferably cosine similarity or similarity based on Euclidean distance.

[0046] In this embodiment, the third stage upgrades "single-point detection" to "two-dimensional area array imaging detection," which directly captures the distribution pattern of leaked gas through spatial resolution advantages, and then inverts the location of the leak.

[0047] In this embodiment, it is preferable to visualize the obtained leak location through the data display module, specifically as follows: Step A1: Set calibration targets in the area to be detected, and obtain the physical coordinates of each calibration target and the multi-pixel coordinates in the multi-pixel array; obtain the transformation coefficient based on the physical coordinates and multi-pixel coordinates; Step A2: Based on the obtained conversion coefficient, the pixel coordinates of the obtained leak location are converted to obtain the corresponding physical coordinates. The physical coordinates are then superimposed on the electronic map to complete the visualization output of the leak location.

[0048] The calibration target is preferably set with three or more infrared light sources with known GPS coordinates in the area to be detected; In this embodiment, the standard spectrum described in stage two includes the wavelength, peak shape, and full width at half maximum (FWHM) data of the characteristic peaks.

[0049] In this embodiment, the standard gas spectrum database mentioned in Phase Two comes from laboratory calibration or international standard spectrum libraries.

[0050] In this embodiment, the calibration coefficients described in stage four are related to the excitation light intensity, detector efficiency, optical path length, and the "fluorescence quantum yield" of the gas, and are calibrated experimentally. The fluorescence quantum yield refers to the proportion of excited-state molecules that return to the ground state through resonance fluorescence.

Claims

1. A gas leak detection system, characterized in that, It includes a laser emission module, an infrared imaging detector module, and a data processing module; The laser emitting module is used to emit a mid-infrared laser beam toward the area to be detected; The infrared imaging detector module is used to acquire the infrared spectral signal of the area to be detected in real time; and to send the infrared spectral signal to the data processing module. The data processing module is used to process the received infrared spectral signal to obtain the gas leak detection result of the area to be detected.

2. The gas leak detection system according to claim 1, characterized in that, The infrared imaging detector module includes an imaging optical system and an infrared detector array; The imaging optical system is used to acquire the light signal of the area to be detected in real time and send it to the infrared detector array. The infrared detector array is used to perform photoelectric conversion on the optical signal to obtain an infrared spectral signal.

3. The gas leak detection system according to claim 1, characterized in that, The mid-infrared laser beam is a laser beam with a wavelength of 3.3μm, 3.4μm, or 3.5μm, or a laser beam consisting of a combination of multiple wavelength bands or a combination of wavelength ranges.

4. The gas leak detection system according to claim 3, characterized in that, The multiple band combinations are combinations of the 3.3μm band with any one or more other bands.

5. The gas leak detection system according to any one of claims 1 to 4, characterized in that, The gas leak detection system also includes a data display output module; The data processing module is used to send the obtained gas leak detection results to the data display module; The data display output module is used to display the received gas leak detection results.

6. The gas leak detection system according to claim 1, characterized in that, The gas leak detection result is one or more of the following: the type of leaked gas, the location of the leak, or the concentration of the leak.

7. The gas leak detection system according to claim 6, characterized in that, The data processing module includes the following units: The noise cancellation unit is used to filter out stray light signals in the received infrared spectral signal to obtain a net spectral signal. ; Relative absorption intensity Acquisition unit for background spectrum under leak-free conditions The net spectral signal pass Obtaining relative absorption strength ; The leaked gas type acquisition unit is used to calculate the similarity value between the relative absorption intensity A and the standard spectrum of each gas in the standard gas spectrum database through correlation analysis. If the similarity value is >95%, it is confirmed that there is a leak of the gas type corresponding to the standard spectrum in the area to be detected.

8. The gas leak detection system according to claim 7, characterized in that, The data processing module also includes a leak location acquisition unit, used to determine the leakage location based on the relative absorption intensity of all similarity values ​​> 95%. Obtain the corresponding net spectral signal in the on-spectrum. The location in the detection area is identified as an area with abnormal concentration, which is the location of the gas leak.

9. The gas leak detection system according to claim 7, characterized in that, The data processing module also includes a leaked gas concentration acquisition unit, used to, based on the acquired leaked gas type, through... Obtain the corresponding leaked gas concentration ,in The intensity of resonance fluorescence; This is the calibration coefficient.

Images