A method and device for spectral remote sensing of gas leakage in hydrogen-blended natural gas stations

Abstract

The present invention discloses a method and device for spectral remote sensing of gas leaks at hydrogen-blended natural gas stations. The remote sensing device comprises a laser emitting system, an optical receiving system, a signal processing and data acquisition system, a video acquisition system, a pan / tilt platform, and a power supply. The optical receiving system is connected to the signal processing and data acquisition system, which is in turn connected to the video acquisition system. The laser emitting system, optical receiving system, signal processing and data acquisition system, video acquisition system, and power supply are mounted on the pan / tilt platform, and the power supply is separately connected to the laser emitting system, optical receiving system, signal processing and data acquisition system, video acquisition system, and pan / tilt platform. The present invention utilizes laser light of a specific wavelength to illuminate a leaking gas cloud, obtain the shift of Stokes Raman scattering spectral lines, and achieve qualitative detection of leaked gas.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas remote sensing, and in particular relates to a method and device for spectral remote sensing of gas leakage in a hydrogen-blended natural gas station. Background Art

[0002] The cost of building new pure hydrogen pipelines is very high. Transporting hydrogen through the existing natural gas pipeline network is an important means of achieving long-distance, large-scale, and low-cost hydrogen transportation. However, hydrogen, methane, and hydrogen sulfide are flammable, explosive, toxic, and hazardous gases that are prone to leakage, fire, and explosion due to corrosion perforation, seal failure, and dynamic equipment failure, threatening the personal safety of station personnel. The station currently has point-contact gas sensors for hydrogen, methane, and hydrogen sulfide, such as catalytic combustion, electrochemical, resistive, and optical sensors. These sensors have the characteristics of high monitoring accuracy and good economic efficiency, but they also have the disadvantages of small monitoring and detection space coverage, short sensor life, and are easily affected by meteorological conditions and sensor installation location, resulting in false alarms and missed alarms.

[0003] To address the above issues, it is urgent to deploy a spectral remote sensing hydrogen, methane, and hydrogen sulfide gas leakage monitoring technology with large coverage, high efficiency and accuracy, and real-time early warning, based on the arrangement of point gas sensors at hydrogen-blended natural gas stations, to ensure the safety of station personnel and equipment facilities. Summary of the Invention

[0004] In order to solve the above problems, the present invention discloses a gas leakage spectrum remote sensing device for hydrogen-blended natural gas station, comprising: a laser emission system, an optical receiving system, a signal processing and data acquisition system, a video acquisition system, a pan-tilt platform and a power supply;

[0005] The optical receiving system is connected to the signal processing and data acquisition system;

[0006] The signal processing and data acquisition system is connected to the video acquisition system;

[0007] The laser emission system, optical receiving system, signal processing and data acquisition system, video acquisition system and power supply are arranged on the pan-tilt platform;

[0008] The power supply is connected to the laser emission system, the optical receiving system, the signal processing and data acquisition system, the video acquisition system and the pan-tilt head respectively.

[0009] Furthermore, the laser emission system includes: a laser emitter, an edge filter, a collimator and a laser beam expander;

[0010] The laser emitter, edge filter, collimator and laser beam expander are arranged in sequence on an axis.

[0011] Furthermore, the optical receiving system includes a telescope and a coaxial five-channel detection unit;

[0012] The telescope is connected to the coaxial five-channel detection unit.

[0013] Furthermore, the coaxial five-channel detection unit includes channels, edge filters, a first beam splitter, a second beam splitter, condenser lenses, band-pass filters, a first signal collector, a second signal collector, a third signal collector, a fourth signal collector, and a fifth signal collector;

[0014] The channels include channel inlets, a first cross intersection, a second cross intersection, nitrogen channels, water vapor channels, hydrogen channels, methane channels, and hydrogen sulfide channels;

[0015] The edge filter is arranged at the channel inlet;

[0016] The first beam splitter is arranged at the first cross intersection;

[0017] The second beam splitter is arranged at the second cross intersection;

[0018] The first signal collector, the condenser lens, and the band-pass filter are sequentially arranged on the nitrogen channel;

[0019] The second signal collector, the condenser lens, and the band-pass filter are sequentially arranged on the water vapor channel;

[0020] The third signal collector, the condenser lens, and the band-pass filter are sequentially arranged on the hydrogen channel;

[0021] The fourth signal collector, the condenser lens, and the band-pass filter are sequentially arranged on the methane channel;

[0022] The fifth signal collector, the condenser lens, and the band-pass filter are sequentially arranged on the hydrogen sulfide channel.

[0023] Furthermore, the channels are in a "卄" shape.

[0024] Furthermore, the signal processing and data acquisition system includes a first AC amplifier, a second AC amplifier, a third AC amplifier, a fourth AC amplifier, a fifth AC amplifier, and a central processing unit;

[0025] The first AC amplifier is connected to the first signal collector;

[0026] The second AC amplifier is connected to the second signal collector;

[0027] The third AC amplifier is connected to the third signal collector;

[0028] The fourth AC amplifier is connected to the fourth signal collector;

[0029] The fifth AC amplifier is connected to the fifth signal collector;

[0030] The first AC amplifier, the second AC amplifier, the third AC amplifier, the fourth AC amplifier, and the fifth AC amplifier are respectively connected to the central processing unit;

[0031] The central processing unit includes an analog-to-digital converter, a field programmable logic gate array, a central processing unit, a data acquisition device and a computer.

[0032] Furthermore, the video acquisition system is a visible light camera.

[0033] Furthermore, the pan-tilt platform includes a three-dimensional pan-tilt platform and a pan-tilt platform driving circuit;

[0034] The three-dimensional pan-tilt platform is connected to a pan-tilt platform driving circuit.

[0035] The present invention also discloses a method for spectral remote sensing of gas leakage in a hydrogen-blended natural gas station, comprising:

[0036] The laser emission system emits a pulsed laser of a specific wavelength, which irradiates the leaking gas cloud. The photons collide inelastically with the leaking gas molecules to produce Raman scattered light.

[0037] The optical receiving system receives the Raman scattered light, converts it into an electrical signal after spectroscopic and filtering processing, and sends the electrical signal to the signal processing and data acquisition system;

[0038] Based on the background visible light image data collected by the video acquisition system, the signal processing and data acquisition system processes the electrical signal to obtain a Raman scattering spectrum;

[0039] determining the molecular species of the leaked gas based on the Raman scattering spectrum;

[0040] Determining the location of a gas leak based on the source of the Raman scattered light signal;

[0041] The concentration of the leaked gas is determined based on the ratio of the Raman scattered light of the leaked gas and nitrogen measured simultaneously.

[0042] Furthermore, the Raman shift of the leaked gas molecules is determined by the following formula:

[0043]

[0044] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0045] 1) By irradiating the leaking gas cloud with a laser of a specific wavelength, the displacement of the Stokes Raman scattering spectrum line is obtained to achieve qualitative detection of the leaking gas;

[0046] 2) Combined with the lidar equation, the leaked gas concentration is measured based on the ratio of the Raman scattering signals of the leaked gas and atmospheric nitrogen, achieving quantitative detection of leaked gas;

[0047] 3) Realize remote sensing monitoring and detection of hydrogen, methane and hydrogen sulfide gas leaks, improve the monitoring and detection coverage area, efficiency and accuracy, and solve the problems of missed reports, false alarms and narrow coverage of traditional contact gas sensors.

[0048] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 A flow chart of a method for spectral remote detection of gas leakage in a hydrogen-blended natural gas station according to an embodiment of the present invention is shown;

[0051] Figure 2 A schematic diagram of a gas leakage spectral remote sensing device for a hydrogen-blended natural gas station according to an embodiment of the present invention is shown;

[0052] Figure 3 A schematic structural diagram of a coaxial five-channel detection unit according to an embodiment of the present invention is shown.

[0053] Figure numerals: 1. laser emitter; 2. edge filter; 3. collimator; 4. laser beam expander; 5. Fresnel lens; 6. telescope; 7. edge filter; 8-1. first spectrometer; 8-2. second spectrometer; 9-1. first signal collector; 9-2. second signal collector; 9-3. third signal collector; 9-4. fourth signal collector; 9-5. fifth signal collector; 10-1. first AC amplifier; 10-2. second AC amplifier; 10-3. third AC amplifier; 10-4. fourth AC amplifier; 10-5. fifth AC amplifier; 11. central processing unit; 12. visible light camera; 13. three-dimensional pan-tilt head; 14. pan-tilt head drive circuit; 15. power supply; 16. focusing lens; 17. bandpass filter. DETAILED DESCRIPTION

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0055] Hydrogen-blended natural gas gathering and transmission stations are prone to leaks of flammable, explosive, toxic, and hazardous gases due to seal failure, corrosion, and perforation in equipment and facilities, which can lead to fires, explosions, and air pollution. Therefore, it is urgent to strengthen the monitoring and detection capabilities for gas leaks at these stations.

[0056] Raman spectroscopy is a type of molecular vibration spectroscopy that obtains molecular structure information by measuring the change in the frequency of scattered light relative to the incident light. It is independent of the frequency of the incident photons and the difference in molecular transition energy levels.

[0057] Figure 1 The flowchart of the method for spectral remote detection of gas leakage in a hydrogen-blended natural gas station according to an embodiment of the present invention is shown. Figure 1 As shown, the present invention proposes a method for spectral remote sensing of gas leakage at a hydrogen-blended natural gas station, comprising the following steps:

[0058] S101. The laser emission system emits a pulsed laser of a specific wavelength. The laser irradiates a leaking gas cloud, such as hydrogen, methane, or hydrogen sulfide. Inelastic collisions between photons and leaking gas molecules cause a small number of photon frequencies and directions to change based on the molecular scattering cross sections, generating Raman scattered light. (Raman scattered light is a component with a different wavelength and frequency than the incident laser light; the longer-wavelength scattered light is Stokes Raman scattered light.) For example, the pulsed laser has a wavelength of 355 nm, a power of 60 mJ, and a frequency of 20 Hz.

[0059] S102. The optical receiving system receives the Stokes Raman scattered light signal generated by the leaking gas cloud, converts it into an electrical signal after spectroscopic and filtering processing, and sends the electrical signal to the signal processing and data acquisition system.

[0060] S103. Based on the background visible light image data collected by the video acquisition system, the signal processing and data acquisition system processes the electrical signal to obtain a Raman scattering spectrum. The displacement change generated by the Stokes Raman scattering light signal is obtained according to the Raman scattering spectrum to qualitatively detect the type of leaked gas molecules. The Stokes Raman scattering wavelength shift depends on the type of molecule, so the type of molecule can be identified from the wavelength of the Stokes light. The Raman shift calculation formula is shown in formula (1). Qualitative detection of leaked gas can be performed based on the Raman spectrum shift of common gases in natural gas gathering and transportation stations.

[0061]

[0062] Taking the use of a Q-switched pulsed Nd:YAG laser (355nm, 60mJ, 20Hz) as the laser light source as an example, under 355nm incident laser irradiation, the Raman scattered light wavelengths of some leaked gas molecules are as follows: nitrogen, water vapor, hydrogen, methane, and hydrogen sulfide gases have Raman scattered light wavelengths of 386.7nm, 407.8nm, 416nm, 395.6nm, and 390.9nm, respectively.

[0063] Taking the Nd:YAG laser (second harmonic wavelength 532nm, 5-7ns, 10Hz) as the laser light source as an example, under 355nm incident laser irradiation, the Raman scattered light wavelengths of some leaked gas molecules are as follows: nitrogen, water vapor, hydrogen, methane, and hydrogen sulfide gases have Raman scattered light wavelengths of 607.31nm, 660.28nm, 683.01nm, 629.72nm, and 617.44nm, respectively.

[0064] S104. Determine the location of the gas leak point based on the source of the Stokes Raman scattering light signal.

[0065] S105. Using the back echo signal of the stable nitrogen content in the atmosphere as a reference value, the concentration of the leaked gas is determined based on the ratio of the Raman scattered light of the leaked gas and the nitrogen measured simultaneously. For example, the Raman scattered light of the leaked gas and the nitrogen can be calculated according to the following lidar equation (2).

[0066] Taking hydrogen as an example, the quantitative calculation method for hydrogen leakage concentration is as follows:

[0067]

[0068] Among them, S Gas is the Raman scattered light signal of the leaked gas; SN2 is the Raman scattered light signal of nitrogen in the atmosphere; η is the photon efficiency of the detector (signal collector in the coaxial five-channel detection unit); P0 is the laser power; K is the acquisition efficiency of the optical receiving system; Y(r) is the overlap function of the transmitted laser beam and the field of view of the light receiver (optical receiving system); A is the light receiving surface area of ​​the light receiver; r is the telemetry distance (i.e., the distance between the leaking gas cloud and the telemetry device); N is the gas density; σ is the Raman scattering cross section; c is the speed of light; τ is the laser pulse width; α L is the extinction coefficient; α R is the extinction coefficient of Raman scattered light.

[0069] The Raman scattering light signals of the gas leaked into the air and the atmospheric N2 were measured simultaneously by Raman lidar, and the Raman scattering light signals of the gas leaked into the air and the atmospheric N2 were measured according to the S Gas (r) / S N2 (r) The concentration of leaked gases such as hydrogen, methane, and hydrogen sulfide can be obtained.

[0070] The present invention provides a spectral remote sensing method for gas leakage at a hydrogen-blended natural gas station. This method uses a laser of a specific wavelength to illuminate a leaking gas cloud, obtain the displacement of the Stokes Raman scattering spectrum line, and achieve qualitative detection of leaked gas. Combined with the lidar equation, the method measures the leaked gas concentration based on the ratio of the Raman scattering signals of the leaked gas and atmospheric nitrogen measured simultaneously, and achieves quantitative detection of leaked gas.

[0071] like Figure 2 As shown, based on the above-mentioned hydrogen-blended natural gas station gas leakage spectral remote sensing method, this embodiment proposes a hydrogen-blended natural gas station gas leakage spectral remote sensing device, including: a laser emission system, an optical receiving system, a signal processing and data acquisition system, a video acquisition system, a pan / tilt platform, and a power supply 15;

[0072] The optical receiving system is connected to the signal processing and data acquisition system;

[0073] The signal processing and data acquisition system is connected to the video acquisition system;

[0074] The laser emission system, optical receiving system, signal processing and data acquisition system, video acquisition system and power supply 15 are arranged on the pan-tilt platform;

[0075] The power supply 15 is connected to the laser emission system, the optical receiving system, the signal processing and data acquisition system, the video acquisition system and the pan / tilt head respectively.

[0076] A laser emission system, used for emitting lasers of a specific wave field;

[0077] An optical receiving system, used for receiving Raman scattered light and converting it into an electrical signal;

[0078] Signal processing and data acquisition system, used to process electrical signals, obtain Raman scattering spectra, and obtain the molecular species of leaked gas;

[0079] Video acquisition system, used to collect background visible light image data;

[0080] The gimbal is used to provide the required horizontal and vertical shooting angles;

[0081] The power supply 15 is used to provide power to the laser emission system, optical receiving system, signal processing and data acquisition system, video acquisition system, and pan / tilt head.

[0082] The present invention provides a gas leakage spectral telemetry device for hydrogen-blended natural gas stations, which realizes remote sensing monitoring and detection of hydrogen, methane and hydrogen sulfide gas leakage, improves the monitoring and detection coverage area, efficiency and accuracy, and solves the problems of missed reports, false reports and narrow coverage of traditional contact gas sensors.

[0083] In some embodiments, the laser emission system includes: a laser emitter 1, an edge filter 2, a collimator 3, a laser beam expander 4 and a reflector;

[0084] The laser emitter 1, edge filter 2, collimator 3, and laser beam expander 4 are sequentially arranged on an axis. A reflector can be arranged at a certain position in the laser light path according to actual needs to change the laser emission direction.

[0085] Laser transmitter 1, used for emitting pulsed monochromatic light of specific wavelength, frequency and power;

[0086] an edge filter 2 for filtering stray light other than a specific wavelength emitted by the laser transmitter 1;

[0087] A collimator 3, used for focusing and collimating the divergent laser beam emitted from the resonant cavity of the laser transmitter;

[0088] A laser beam expander 4 is used to expand the diameter of a parallel input beam to a parallel output beam with a larger diameter and divergence angle;

[0089] Reflector, used to change the direction of laser light propagation.

[0090] The laser emission system can emit lasers of specific wavelengths according to actual needs, making it easier to identify the types of leaking gas molecules.

[0091] In some embodiments, the optical receiving system includes a telescope 6 and a coaxial five-channel detection unit;

[0092] A Fresnel lens 5 is provided in the telescope 6;

[0093] The telescope 6 is connected to a coaxial five-channel detection unit.

[0094] A telescope 6, which is used to receive and collect the Raman scattered light generated after the collision of monochromatic laser photons with hydrogen-doped natural gas leakage gas;

[0095] A coaxial five-channel detection unit, which is used to divide the axially incident Raman scattered light into five channels for selective detection of five gases, namely nitrogen, water vapor, hydrogen, methane, and hydrogen sulfide.

[0096] As Figure 3 shown, in some embodiments, the coaxial five-channel detection unit includes a channel, an edge filter 7, a first beam splitter 8-1, a second beam splitter 8-2, a condenser lens 16, a band-pass filter 17, a first signal collector 9-1, a second signal collector 9-2, a third signal collector 9-3, a fourth signal collector 9-4, and a fifth signal collector 9-5;

[0097] The channel is in a "卄" shape and includes a channel entrance, a first cross intersection, a second cross intersection, a nitrogen channel, a water vapor channel, a hydrogen channel, a methane channel, and a hydrogen sulfide channel;

[0098] The edge filter 7 is arranged at the channel entrance;

[0099] The first beam splitter 8-1 is arranged at the first cross intersection;

[0100] The second beam splitter 8-2 is arranged at the second cross intersection;

[0101] The first signal collector 9-1, the condenser lens 16, and the band-pass filter 17 are sequentially arranged on the nitrogen channel;

[0102] The second signal collector 9-2, the condenser lens 16, and the band-pass filter 17 are sequentially arranged on the water vapor channel;

[0103] The third signal collector 9-3, the condenser lens 16, and the band-pass filter 17 are sequentially arranged on the hydrogen channel;

[0104] The fourth signal collector 9-4, the condenser lens 16, and the band-pass filter 17 are sequentially arranged on the methane channel;

[0105] The fifth signal collector 9-5, the condenser lens 16, and the band-pass filter 17 are sequentially arranged on the hydrogen sulfide channel. Among them, the band-pass filter 17 is close to the cross intersection.

[0106] The edge filter 7 is used to filter interference signals such as laser light sources and background scattered light;

[0107] The first beam splitter 8-1 is used to perform spectroscopic processing on the Raman scattered light of the leakage gas received and nitrogen and water vapor in the atmosphere;

[0108] The second spectrometer 8-2 is used to perform spectroscopic processing on the Raman scattered light of the leaked gas of hydrogen, methane and hydrogen sulfide after filtering out atmospheric nitrogen and water vapor;

[0109] The focusing lens 16 is used to focus the Raman scattered light of five gases: nitrogen, water vapor, hydrogen, methane, and hydrogen sulfide;

[0110] a bandpass filter 17 for selectively acquiring and passing Raman scattered light of leaked gas of a specific wavelength;

[0111] The first signal collector 9-1 is used to convert the weak Raman scattered light signal of nitrogen into an electrical signal;

[0112] The second signal collector 9-2 is used to convert the weak Raman scattered light signal of water vapor into an electrical signal;

[0113] The third signal collector 9-3 is used to convert the weak Raman scattered light signal of hydrogen into an electrical signal;

[0114] The fourth signal collector 9-4 is used to convert the weak Raman scattered light signal of methane gas into an electrical signal;

[0115] The fifth signal collector 9-5 is used to convert the weak Raman scattered light signal of hydrogen sulfide gas into an electrical signal.

[0116] The coaxial five-channel detection unit is used to detect the response gases of the nitrogen channel, water vapor channel, hydrogen channel, methane channel, and hydrogen sulfide channel respectively at the same time, reducing the differences and interference of the five gas spectra in the time domain, improving the gas identification resolution, and realizing the synchronous detection of nitrogen, the main gas component in the atmospheric environment, water vapor with strong noise interference, and methane, hydrogen and hydrogen sulfide, which are major hazardous gases in hydrogen-blended natural gas stations.

[0117] In some embodiments, the signal processing and data acquisition system includes a first AC amplifier 10 - 1 , a second AC amplifier 10 - 2 , a third AC amplifier 10 - 3 , a fourth AC amplifier 10 - 4 , a fifth AC amplifier 10 - 5 and a central processing unit 11 ;

[0118] The first AC amplifier 10-1 is connected to the first signal collector 9-1;

[0119] The second AC amplifier 10-2 is connected to the second signal collector 9-2;

[0120] The third AC amplifier 10-3 is connected to the third signal collector 9-3;

[0121] The fourth AC amplifier 10-4 is connected to the fourth signal collector 9-4;

[0122] The fifth AC amplifier 10-5 is connected to the fifth signal collector 9-5;

[0123] The first AC amplifier 10-1, the second AC amplifier 10-2, the third AC amplifier 10-3, the fourth AC amplifier 10-4, and the fifth AC amplifier 10-5 are respectively connected to the central processing unit 11;

[0124] The central processing unit 11 includes an analog-to-digital converter (A / D converter), a field programmable gate array (FPGA), a central processing unit (CPU), a personal digital assistant (PDA) and a computer (PC).

[0125] The first AC amplifier 10-1 is used to amplify the nitrogen electrical signal and amplify the nitrogen weak Raman scattering signal to the voltage required by the A / D converter;

[0126] The second AC amplifier 10-2 is used to amplify the water vapor electrical signal and amplify the water vapor weak Raman scattering signal to the voltage required by the A / D converter;

[0127] The third AC amplifier 10-3 is used to amplify the hydrogen electrical signal and amplify the hydrogen weak Raman scattering signal to the voltage required by the A / D converter;

[0128] The fourth AC amplifier 10-4 is used to amplify the methane gas electrical signal and amplify the methane gas weak Raman scattering signal to the voltage required by the A / D converter;

[0129] The fifth AC amplifier 10-5 is used to amplify the hydrogen sulfide gas electrical signal and amplify the weak Raman scattering signal of the hydrogen sulfide gas to the voltage required by the A / D converter;

[0130] Analog-to-digital converter, used to convert the input voltage signal into an output digital signal;

[0131] Field programmable logic gate array, used to realize signal acquisition control and signal processing;

[0132] Central processing unit, used to perform information processing and program execution;

[0133] Data collector, used for real-time data collection, storage, transmission and processing;

[0134] Computers are used for image,data processing, storage, and visualization.

[0135] The signal processing and data acquisition system is equipped with multiple AC amplifiers, which can simultaneously amplify the electrical signals of nitrogen, water vapor, hydrogen, methane, and hydrogen sulfide gas to the required voltage, and convert the voltage signals into output digital signals.

[0136] In some embodiments, the video acquisition system is a visible light camera 12 .

[0137] The visible light camera 12 is used to collect background visible light image data.

[0138] The collected background visible light image data is used to superimpose with the visualized Raman spectrum data in the later stage, which facilitates the visual monitoring and early warning effect of leaked gas, and roughly traces the leak point by comparing with the background visible light image data.

[0139] In some embodiments, the pan-tilt platform includes a three-dimensional pan-tilt platform 13 and a pan-tilt platform driving circuit 14;

[0140] The three-dimensional pan-tilt platform 13 is connected to a pan-tilt platform driving circuit 14 .

[0141] A three-dimensional pan-tilt platform 13 is used to provide angles that meet the requirements of horizontal and pitch field of view shooting;

[0142] The pan-tilt platform driving circuit 14 is used to accurately control the motor current and voltage of the three-dimensional pan-tilt platform 13.

[0143] The pan-tilt drive circuit 14 can accurately control the motor current and voltage of the three-dimensional pan-tilt platform 13 according to requirements to provide an optimal shooting angle.

[0144] Taking a Q-switched pulsed Nd:YAG laser (355nm, 60mJ, 20Hz) as an example, the pump laser, laser-induced fluorescence signal, ambient light, and Raman scattered light of the gas to be measured (hydrogen, water vapor, nitrogen, methane, hydrogen sulfide) are collected by a telescope 6 and enter the main axis channel of the coaxial five-channel detection unit. After passing through a 355nm edge filter 7, background noise such as pump laser, laser-induced fluorescence signal, and ambient light with wavelengths less than 355nm are filtered out, while Raman scattered light of the gas to be measured with wavelengths greater than 355nm is transmitted.

[0145] The Raman scattered light of the gas to be measured (hydrogen, water vapor, nitrogen, methane, hydrogen sulfide) propagates in the main axis channel. The first 400nm spectrometer 8-1 spectroscopically processes the Raman scattered light of hydrogen (416.1nm) and water vapor (407.8nm) with wavelengths greater than 400nm, and nitrogen (386.7nm), methane (395.6nm), and hydrogen sulfide (390nm) with wavelengths less than 400nm.

[0146] Among them, the 416nm bandpass filter 17 in the hydrogen channel is used to selectively acquire and pass hydrogen Raman scattered light, which is then focused by the condenser lens 16 and propagated to the photon counting type third signal collector 9-3 for measurement;

[0147] The water vapor channel 408nm bandpass filter 17 is used to selectively acquire and pass the water vapor Raman scattered light, and after being focused by the focusing lens 16, it is transmitted to the photon counting type second signal collector 9-2 for measurement;

[0148] After passing through the first spectrometer 8-1, the Raman scattered light signals of nitrogen, methane, and hydrogen sulfide continue to propagate along the main axis channel to the second spectrometer 8-2 at 390 nm. The second spectrometer 8-2 separates the Raman scattered light of methane (395.6 nm) with a wavelength greater than 390 nm and the Raman scattered light of nitrogen (386.7 nm) and hydrogen sulfide (390 nm) with a wavelength less than or equal to 390 nm.

[0149] The 387nm bandpass filter 17 in the nitrogen channel is used to selectively acquire and pass the nitrogen Raman scattered light, which is then focused by the focusing lens 16 and propagated to the photon counting type first signal collector 9-1 for measurement;

[0150] The 396nm bandpass filter 17 in the methane gas channel is used to selectively acquire and pass the methane Raman scattered light, which is then focused by the focusing lens 16 and propagated to the photon counting type fourth signal collector 9-4 for measurement;

[0151] The 390nm bandpass filter 17 in the hydrogen sulfide gas channel is used to selectively acquire and pass hydrogen sulfide Raman scattered light, which is then focused by the condenser lens 16 and then transmitted to the photon counting type fifth signal collector 9-5 for measurement.

[0152] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas leakage spectrum remote sensing device for hydrogen-blended natural gas station, characterized in that: Including: a laser emission system, an optical reception system, a signal processing and data acquisition system, a video acquisition system, a pan-tilt head, and a power supply (15); The optical reception system is connected to the signal processing and data acquisition system; The signal processing and data acquisition system is connected to the video acquisition system; The laser emission system, the optical reception system, the signal processing and data acquisition system, the video acquisition system, and the power supply (15) are arranged on the pan-tilt head; The power supply (15) is respectively connected to the laser emission system, the optical reception system, the signal processing and data acquisition system, the video acquisition system, and the pan-tilt head; The optical reception system includes a telescope (6) and a coaxial five-channel detection unit; The telescope (6) is connected to the coaxial five-channel detection unit; The coaxial five-channel detection unit includes channels, an edge filter (7), a first beam splitter (8-1), a second beam splitter (8-2), a condenser lens (16), a band-pass filter (17), a first signal collector (9-1), a second signal collector (9-2), a third signal collector (9-3), a fourth signal collector (9-4), and a fifth signal collector (9-5); The channels are in a "plus" shape; the channels include a channel entrance, a first cross intersection, a second cross intersection, a nitrogen channel, a water vapor channel, a hydrogen channel, a methane channel, and a hydrogen sulfide channel; The edge filter (7) is arranged at the channel entrance; The first beam splitter (8-1) is arranged at the first cross intersection; The second beam splitter (8-2) is arranged at the second cross intersection; The first signal collector (9-1), the condenser lens (16), and the band-pass filter (17) are sequentially arranged on the nitrogen channel; The second signal collector (9-2), the condenser lens (16), and the band-pass filter (17) are sequentially arranged on the water vapor channel; The third signal collector (9-3), the condenser lens (16), and the band-pass filter (17) are sequentially arranged on the hydrogen channel; The fourth signal collector (9-4), the condenser lens (16), and the band-pass filter (17) are sequentially arranged on the methane channel; The fifth signal collector (9-5), the condenser lens (16), and the band-pass filter (17) are sequentially arranged on the hydrogen sulfide channel.

2. The gas leakage spectrum remote sensing device for hydrogen-blended natural gas station according to claim 1, characterized in that: The laser emission system includes: a laser emitter (1), an edge filter (2), a collimator (3), and a laser beam expander (4); The laser emitter (1), the edge filter (2), the collimator (3), and the laser beam expander (4) are sequentially arranged on one axis.

3. The gas leakage spectrum remote sensing device for hydrogen-blended natural gas station according to claim 1, characterized in that: The signal processing and data acquisition system includes a first AC amplifier (10-1), a second AC amplifier (10-2), a third AC amplifier (10-3), a fourth AC amplifier (10-4), a fifth AC amplifier (10-5), and a central processing unit (11); The first AC amplifier (10-1) is connected to the first signal collector (9-1); The second AC amplifier (10-2) is connected to the second signal collector (9-2); The third AC amplifier (10-3) is connected to the third signal collector (9-3); The fourth AC amplifier (10-4) is connected to the fourth signal collector (9-4); The fifth AC amplifier (10-5) is connected to the fifth signal collector (9-5); The first AC amplifier (10-1), the second AC amplifier (10-2), the third AC amplifier (10-3), the fourth AC amplifier (10-4), and the fifth AC amplifier (10-5) are respectively connected to the central processing unit (11); The central processing unit (11) includes an analog-to-digital converter, a field programmable logic gate array, a central processing unit, a data acquisition unit, and a computer.

4. The gas leakage spectrum remote sensing device for hydrogen-blended natural gas station according to claim 1, characterized in that: The video acquisition system is a visible light camera (12).

5. The gas leakage spectrum remote sensing device for hydrogen-blended natural gas station according to claim 1, characterized in that: The pan-tilt platform comprises a three-dimensional pan-tilt platform (13) and a pan-tilt platform driving circuit (14); The three-dimensional pan-tilt platform (13) is connected to a pan-tilt platform drive circuit (14).

6. A method for spectral remote sensing of gas leakage at a hydrogen-blended natural gas station, used for the spectral remote sensing device for gas leakage at a hydrogen-blended natural gas station according to any one of claims 1 to 5, characterized in that: include: The laser emission system emits a pulsed laser of a specific wavelength, which irradiates the leaking gas cloud. The photons collide inelastically with the leaking gas molecules to produce Raman scattered light. The optical receiving system receives the Raman scattered light, converts it into an electrical signal after spectroscopic and filtering processing, and sends the electrical signal to the signal processing and data acquisition system; Based on the background visible light image data collected by the video acquisition system, the signal processing and data acquisition system processes the electrical signal to obtain a Raman scattering spectrum; determining the molecular species of the leaked gas based on the Raman scattering spectrum; Determining the location of a gas leak based on the source of the Raman scattered light signal; The concentration of the leaked gas is determined based on the ratio of the Raman scattered light of the leaked gas and nitrogen measured simultaneously.

7. The method for spectral remote sensing of gas leakage at a hydrogen-blended natural gas station according to claim 6, characterized in that: The Raman shift of the leaked gas molecules is determined by the following formula: 。

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