Spectral telemetering method and device for gas leakage of hydrogen-doped natural gas station

Abstract

The invention discloses a spectral remote measurement method and device for gas leakage of a hydrogen-doped natural gas station. The remote measurement device comprises a laser emission system, an optical receiving system, a signal processing and data acquisition system, a video acquisition system, a holder and a power supply. The optical receiving system is connected with the signal processing and data acquisition system; the signal processing and data acquisition system is connected with the video acquisition system; the laser emission system, the optical receiving system, the signal processing and data acquisition system, the video acquisition system and the power supply are arranged on the holder; the power supply is connected with the laser emission system, the optical receiving system, the signal processing and data acquisition system, the video acquisition system and the holder. The leakage gas cloud cluster is irradiated through the laser with the specific wavelength, the displacement of the Stokes Raman scattering spectral line is obtained, and qualitative detection of the leakage gas is achieved.

Description

Technical Field

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

[0002] The cost of building a new pure hydrogen pipeline is very high. The transportation of hydrogen blending through the existing natural gas pipeline network is an important means to achieve long-distance, large-scale, and low-cost transportation of hydrogen. However, as a type of flammable, explosive, toxic and harmful gas, hydrogen, methane, and hydrogen sulfide are very likely to cause major safety risks such as 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 hydrogen, methane, and hydrogen sulfide point-contact gas sensors, such as catalytic combustion, electrochemical, resistive, and optical sensors, which have the characteristics of high monitoring and detection accuracy and good economy, but they also have the problems of small monitoring and detection space coverage, short sensor life, and are easily affected by meteorological conditions and sensor installation locations, resulting in false alarms and missed alarms.

[0003] In response to the above problems, it is urgent to deploy a spectral remote sensing hydrogen, methane, and hydrogen sulfide gas leakage monitoring technology with a large coverage, high efficiency and accuracy, and real-time early warning on the basis of arranging 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 view of the above problems, the present invention discloses a gas leakage spectrum telemetry device for a hydrogen-doped 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 respectively 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 platform.

[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 a channel, an edge filter, a first beam splitter, a second beam splitter, a condenser lens, a band-pass filter, a first signal collector, a second signal collector, a third signal collector, a fourth signal collector, and a fifth signal collector;

[0014] The channel includes a channel entrance, a first crossroads, a second crossroads, a nitrogen channel, a water vapor channel, a hydrogen channel, a methane channel, and a hydrogen sulfide channel;

[0015] The edge filter is disposed at the channel entrance;

[0016] The first beam splitter is disposed at the first crossroads;

[0017] The second beam splitter is disposed at the second crossroads;

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

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

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

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

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

[0023] Furthermore, the channel is 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 includes a three-dimensional pan / tilt and a pan / tilt 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 gas leakage spectral telemetry method for a hydrogen-blended natural gas station, comprising:

[0036] The laser emission system emits a pulsed laser of a specific wavelength to irradiate the leaking gas cloud. Raman scattered light is generated after the photons collide inelastically with the leaking gas molecules.

[0037] The optical receiving system receives the Raman scattered light, converts it into an electrical signal after splitting and filtering, 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] Determine the type of leaked gas molecules based on the Raman scattering spectrum;

[0040] Determine the location of the gas leakage point 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 laser radar equation, the concentration of the leaked gas is measured according to the ratio of the Raman scattering signals of the leaked gas and atmospheric nitrogen measured simultaneously, thus realizing quantitative detection of the 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 underreporting, 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 partly become apparent from the description, or 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 briefly introduces 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 creative work.

[0050] Figure 1 A flow chart of a method for spectral remote sensing 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 transmitter; 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 gimbal; 14. gimbal drive circuit; 15. power supply; 16. focusing lens; 17. bandpass filter. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0055] Hydrogen-blended natural gas gathering and transportation stations are prone to leaking flammable, explosive, toxic and harmful gas media due to sealing failure, corrosion and perforation of equipment and facilities, which can lead to accidents such as fire, explosion and air pollution. Therefore, it is urgent to strengthen the monitoring and detection capabilities of gas leakage in 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 energy level difference of molecular transitions.

[0057] Figure 1 The flowchart of the method for spectral telemetry 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 in 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, and hydrogen sulfide. After the photons collide inelastically with the leaking gas molecules, the frequency of a small number of photons and the direction of the light change according to the different molecular scattering cross sections, generating Raman scattered light (Raman scattered light is a component different from the wavelength and frequency of the incident laser, and the scattering with a longer wavelength is Stokes Raman scattered light). Exemplarily, the wavelength of the pulsed laser is 355nm, the power is 60mJ, and the frequency is 20Hz.

[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 splitting and filtering, 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 amount 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 displacement amount depends on the type of molecule. Therefore, the type of molecule can be identified from the wavelength of the Stokes light. The Raman shift calculation formula is shown in formula (1). The leaked gas can be qualitatively detected according to the Raman spectrum displacement of common gases in natural gas gathering and transportation stations.

[0061]

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

[0063] Taking 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 scattering light wavelengths of some leaked gas molecules are as follows: the Raman scattering light wavelengths of nitrogen, water vapor, hydrogen, methane, and hydrogen sulfide gas are 607.31nm, 660.28nm, 683.01nm, 629.72nm, and 617.44nm, respectively.

[0064] S104. Determine the location of the gas leakage point according to 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 according to the ratio of the Raman scattered light of the leaked gas and the nitrogen measured simultaneously. Exemplarily, the Raman scattered light of the leaked gas and the nitrogen can be calculated according to the following laser radar equation (2).

[0066] Taking hydrogen as an example, the quantitative calculation method of 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 collection efficiency of the optical receiving system; Y(r) is the overlap function of the emitted laser beam and the field of view of the optical receiver (optical receiving system); A is the light receiving surface area of ​​the optical 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 leaking into the air and the atmospheric N2 were measured simultaneously by Raman lidar, and the Raman scattering light signals of the gas leaking 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 gas leakage spectral telemetry method for a hydrogen-blended natural gas station. The method irradiates a leaking gas cloud with a laser of a specific wavelength to obtain the displacement of the Stokes Raman scattering spectrum line, thereby realizing qualitative detection of the leaking gas. The method is combined with a laser radar equation to measure the concentration of the leaking gas according to the ratio of the Raman scattering signals of the leaking gas and atmospheric nitrogen measured simultaneously, thereby realizing quantitative detection of the leaking gas.

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

[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] A video acquisition system, used to acquire background visible light image data;

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

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

[0082] The invention discloses a gas leakage spectral telemetry device for a hydrogen-blended natural gas station, 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 underreporting, false alarm 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. Among them, the reflector can be arranged at a certain position of 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, used 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, used to expand the diameter of a parallel input beam to a parallel output beam of 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 arranged 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 Raman scattered light generated after monochromatic laser photons collide 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, and selectively detect 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 beam splitting 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] A condenser lens 16 is used to collect Raman scattered light of five gases: nitrogen, water vapor, hydrogen, methane, and hydrogen sulfide;

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

[0111] A first signal collector 9-1, 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 scattering 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, reduce the differences and interferences of the five gas spectra in the time domain, improve the gas identification resolution, and realize 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 dangerous 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 data acquisition device (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] A fifth AC amplifier 10-5 is used to amplify the hydrogen sulfide gas electrical signal and amplify the hydrogen sulfide gas weak Raman scattering signal to a voltage required by the A / D converter;

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

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

[0132] The central processing unit is 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 gases 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 later, which is convenient for visual monitoring and early warning of leaked gas, and the leakage point can be roughly traced 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 shooting;

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

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

[0144] Taking the use of Q-switched pulsed Nd:YAG laser (355nm, 60mJ, 20Hz) as a laser light source 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 gas) are collected by the telescope 6 and enter the main axis channel of the coaxial five-channel detection unit. After passing through the 355nm edge filter 7, the pump laser, laser-induced fluorescence signal, ambient light and other background noises less than 355nm are filtered out, and the Raman scattered light of the gas to be measured 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, and the first 400nm spectrometer 8-1 performs spectroscopic processing on the Raman scattered light of hydrogen (416.1nm), water vapor (407.8nm) with a wavelength greater than 400nm, and nitrogen (386.7nm), methane (395.6nm), hydrogen sulfide (390nm) with a wavelength 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, and after being focused by the focusing lens 16, it is transmitted 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 of 390nm. The second spectrometer 8-2 performs spectroscopic processing on the Raman scattered light of methane (395.6nm) with a wavelength greater than 390nm and nitrogen (386.7nm) and hydrogen sulfide (390nm) with a wavelength less than or equal to 390nm.

[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 the hydrogen sulfide Raman scattered light, and after being focused by the focusing lens 16, it is 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 substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas leakage spectral remote sensing device for a hydrogen-blended natural gas station, characterized in that: It includes: 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.

2. The gas leakage spectral 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 an axis.

3. The gas leakage spectral remote sensing device for hydrogen-blended natural gas station according to claim 1, characterized in that: 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.

4. The gas leakage spectral remote sensing device for hydrogen-blended natural gas station according to claim 3 is characterized in that: The coaxial five-channel detection unit includes channels, an edge filter sheet (7), a first beam splitter (8-1), a second beam splitter (8-2), a condenser lens (16), a band-pass filter sheet (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 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 sheet (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 sheet (17) are sequentially arranged on the nitrogen channel; The second signal collector (9-2), the condenser lens (16), and the band-pass filter sheet (17) are sequentially arranged on the water vapor channel; The third signal collector (9-3), the condenser lens (16), and the band-pass filter sheet (17) are sequentially arranged on the hydrogen channel; The fourth signal collector (9-4), the condenser lens (16), and the band-pass filter sheet (17) are sequentially arranged on the methane channel; The fifth signal collector (9-5), the condenser lens (16), and the band-pass filter sheet (17) are sequentially arranged on the hydrogen sulfide channel.

5. The gas leakage spectral remote sensing device for hydrogen-blended natural gas station according to claim 4, characterized in that: The channels are in a "卄" shape.

6. The gas leakage spectral remote sensing device for hydrogen-blended natural gas station according to claim 4, 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) comprises an analog-to-digital converter, a field programmable logic gate array, a central processing unit, a data acquisition device and a computer.

7. The gas leakage spectral 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).

8. The gas leakage spectral 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 driving circuit (14).

9. A method for spectral remote sensing of gas leakage in a hydrogen-blended natural gas station, characterized in that: include: The laser emission system emits a pulsed laser of a specific wavelength to irradiate the leaking gas cloud. Raman scattered light is generated after the photons collide inelastically with the leaking gas molecules. The optical receiving system receives the Raman scattered light, converts it into an electrical signal after splitting and filtering, 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; Determine the type of leaked gas molecules based on the Raman scattering spectrum; Determine the location of the gas leakage point 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.

10. The method for spectral remote sensing of gas leakage in a hydrogen-blended natural gas station according to claim 9, characterized in that: The Raman shift of the leaked gas molecules is determined by the following formula:

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