Hydrogen leakage on-line detection system and method based on quadrupole rod mass spectrometry technology

Abstract

The invention discloses a hydrogen leakage on-line detection system and method based on a quadrupole mass spectrometry technology, and belongs to the technical field of hydrogen detection.The detection system comprises a gas inlet module, a dynamic dilution module, a six-way valve quantitative sample injection module and a quadrupole mass spectrometry detection system, and rapid and sensitive quantitative detection of hydrogen can be achieved; the usage amount of gas standard substances and samples is saved, and the method is green, efficient and energy-saving. The detection method comprises the following steps: establishing a calibration curve, and calculating the concentration value of an unknown hydrogen sample according to the absolute signal intensity value of the unknown hydrogen sample. The gas standard substance with high concentration is diluted on line to obtain samples with different concentrations, and quantitative detection of trace hydrogen components can be reliably realized for samples with different pressures such as pipelines / gas cylinders, ambient air and the like. The device can be used for on-line measurement of hydrogen components in various industrial gases in high-pressure pipelines or steel cylinders, on-line monitoring of hydrogen leakage in hydrogen related places such as hydrogen refueling stations, and on-line measurement of hydrogen components in scenes such as closed spaces and field exploration.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen detection, and in particular relates to an online hydrogen leakage detection system and method based on quadrupole mass spectrometry technology. Background Art

[0002] hydrogen( Hydrogen is a single substance formed by the element hydrogen. At room temperature and pressure, hydrogen is a colorless, tasteless, odorless, non-toxic, highly flammable, and poorly soluble gas. It is widely used in the chemical, petroleum, laboratory, medical, fuel cell, aerospace, and food and pharmaceutical industries. With its unique advantages, such as high energy density, environmental friendliness, and high diffusivity, hydrogen is considered a potential alternative to traditional energy sources, effectively reducing CO2 emissions while maintaining high efficiency. Therefore, accurate monitoring of hydrogen concentration is crucial for optimizing process flows and ensuring compliance with final product specifications.

[0003] However, due to its small size, explosiveness, and low reactivity, hydrogen molecules can easily leak into the environment, causing serious casualties and property damage. Therefore, rapid and highly sensitive detection of trace hydrogen in ambient air, enabling early warning before accidents occur, is crucial. However, precisely because of its small molecular weight, hydrogen's inherent properties make detection, quantification, and monitoring of trace amounts more challenging than other gases.

[0004] At present, the most widely used hydrogen sensor on the market is the hydrogen sensor for detecting hydrogen leaks. However, this sensor technology has many defects: long response time (>1 second), insufficient accuracy, poor repeatability, and sensitivity to interferences (such as and CO, etc.), have low selectivity, limited service life (6-12 months), and require high temperature operation (power-consuming heating elements).

[0005] Existing spectroscopic technologies, such as tunable diode laser absorption spectroscopy (TDLAS) and Raman spectroscopy, have a detection limit of >50 ppm, failing to meet the ideal requirement for early leak detection. Although hydrogen detection technology based on gas chromatography can achieve a detection limit of <1 ppm, it has disadvantages such as a complex valve system, a bulky and inconvenient system operation, and time-consuming chromatographic separation and detection of samples (generally >5 minutes).

[0006] In short, the various detection technologies currently available on the market have problems such as short lifespan, poor selectivity, bulky and inconvenient system operation, long detection time, and detection limits that cannot reach the ppb level. They have not yet been able to truly achieve highly sensitive early detection and early warning of hydrogen leaks. Summary of the Invention

[0007] The application aims to provide a hydrogen leakage online detection system and method based on quadrupole mass spectrometry technology, so as to solve the problems of short service life, poor selectivity, large system, inconvenient operation, long detection time and ppb level detection limit of the existing detection technology.

[0008] The application aims to achieve the above-mentioned purpose by the following technical solutions. The application aims to achieve the above-mentioned purpose by the following technical solutions. The six-way valve quantitative sampling module comprises a six-way valve, and the six-way valve is provided with a quantitative ring with a sampling amount of 10 mL. The high-pressure air inlet module and the ambient air inlet module are respectively connected with the gas inlet end of the second mass flow controller through pipelines, and the gas inlet end of the first mass flow controller is connected with dilution gas. The quadrupole mass spectrometry detection system comprises, in sequence along the flow path, a quartz inert capillary and a quadrupole mass spectrometry detector, a turbo molecular pump and a vortex pump. The interfaces of the six-way valve are respectively connected with the dynamic dilution module, the carrier gas module and the mass flow meter.

[0009] Further, a three-way joint is arranged between the static mixer and the first mass flow controller and the second mass flow controller, and the outlet ends of the first mass flow controller and the second mass flow controller are respectively connected with the gas inlet end of the static mixer through the three-way joint.

[0010] Further, the high-pressure air inlet module comprises pipeline gas, a high-pressure sample bottle, a gas standard substance gas bottle and a high-pressure multi-position selection valve, the pipeline gas, the high-pressure sample bottle and the gas standard substance gas bottle are respectively connected with the high-pressure multi-position selection valve through pipelines, the high-pressure multi-position selection valve is connected with the gas inlet end of the second mass flow controller through a pipeline, and a first pressure reducing valve is arranged between the high-pressure multi-position selection valve and the second mass flow controller.

[0011] Further, the ambient air inlet module comprises, in sequence, ambient air, a diaphragm pump, a digital pressure gauge and a first back pressure valve, and the outlet end of the ambient air inlet module is located at the rear end of the first pressure reducing valve.

[0012] Further, a second back pressure valve and a digital pressure gauge are arranged in the flow path between the dynamic dilution module and the six-way valve.

[0013] Furthermore, the dilution gas and the carrier gas are both 99.9999% nitrogen, and a second pressure reducing valve is provided between the dilution gas and the first mass flow controller.

[0014] Furthermore, a T-joint is provided between the six-way valve and the quartz inert capillary tube, one interface of the T-joint is used for exhaust, and heating devices are respectively provided outside the six-way valve, quantitative loop and quartz inert capillary tube.

[0015] Furthermore, the detection conditions of the quadrupole mass spectrometer are preferably as follows: the scanning mode is the multiple ion detection mode, the pumping speed of the molecular turbo pump is 60 L / s, the secondary electron multiplier (SEM) detector voltage is 1000 V, the emission current is 800 μA, the dwell time and interval time are 160 ms and 150 ms respectively, the electron energy is 70 eV, and the total system pressure is maintained at arrive mbar.

[0016] The temperature of the six-port valve and the sample loop was set to 100 °C to ensure that there would be no adsorption of the sample. The sampling purge time (30 s) and injection time (30 s) were controlled by a computer program.

[0017] The carrier gas flow rate was 30 mL / min; the flow rate of gas standards and samples was 30 mL / min.

[0018] A method for online detection of hydrogen leaks based on quadrupole mass spectrometry technology comprises the following steps: S1: High-purity nitrogen was used as the carrier gas and the operation was carried out under the set conditions for more than 24 h; S2: Adjust the quadrupole mass spectrometer and set Scanned ion fragments M / Z (mass-to-charge ratio) = 2; S3: Obtain hydrogen gas standard substances with different concentrations in the range of 0~200 ppm ( ) response value, the step S3 includes sub-steps S31-S33: S31: 199.35 ppm was obtained by gravimetric method Gas reference materials, S32: 199.35 ppm The gas standard substance is mixed with the diluent gas (nitrogen) and the dynamic dilution module at different dilution ratios to obtain different concentrations, and no less than 7 concentration points are obtained. Each concentration point is sampled continuously for more than 7 times by quantitative loop injection. The signal intensity of different concentrations is obtained by injection analysis. The signal intensity is the partial pressure value of hydrogen response, and the unit is mbar; S33: subtracting the corresponding baseline response value from the obtained signal intensities of different concentrations to obtain absolute signal intensity values ​​of different concentrations; S4: According to the different concentration values in S3, and the corresponding absolute intensity signal value fitting least squares linear regression curve, that is, the calibration curve is obtained, and the linear regression equation: y = ax + b is obtained, wherein x is the absolute signal intensity value, the unit is mbar; y is the concentration value, the unit is ppm, a is the slope, and b is the intercept; S5: According to the formula , wherein is the standard deviation of the measured value of the 10 blank samples, s is the slope of the calibration curve in step S4, wherein the slope of the calibration curve is consistent with the slope of the linear regression equation, and the LOD is the detection limit, and the ppb level detection limit can be obtained through steps S3-S5; S6: According to the absolute signal intensity value of the unknown hydrogen sample, the concentration value of the unknown sample can be calculated by substituting the linear regression equation in S4.

[0019] The beneficial effects of the present application are: 1) The system and method proposed in the present application are different from the traditional online sampling method, and the amount of sample consumed is small (only 10 mL), the use amount of gas standard substance and sample is saved, and it is green, efficient, green and energy-saving.

[0020] 2) High-concentration gas standard substance is diluted on-line to obtain different concentrations. Different concentrations can be obtained by mixing different dilution ratios through high-precision dynamic dilution module and dilution gas. Multiple bottles of gas standard substances with different concentrations are not required, and the cost is reduced.

[0021] 3) The sample detection is fast, and the detection period of one sample is < 30 s, and the whole detection process is green and efficient.

[0022] 4) The system and method proposed in the present application are not only suitable for low-concentration hydrogen content measurement, but also suitable for high-concentration hydrogen content measurement. When measuring high-concentration hydrogen components, the detector in the quadrupole mass spectrometer is selected as a Faraday detector.

[0023] 5) The system and method proposed in the present application can be used for online measurement of hydrogen components in high-pressure pipelines or steel cylinders of industrial gases, online monitoring of hydrogen leakage in hydrogenation stations and other hydrogen-related places, and online measurement of hydrogen components in closed spaces, field exploration and other scenes. At the same time, other M / Z values (mass-to-charge ratio values) are added in the system software, and the simultaneous measurement of other gas components can also be realized. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a schematic diagram of a hydrogen leakage online detection system based on a quadrupole mass spectrometry technology; In the figure, 11-high-pressure sample bottle, 12-gas standard material cylinder, 13-high-pressure multi-position selector valve, 14-dilution gas, 15-diaphragm pump, 16-digital pressure gauge, 17-first back pressure valve, 18-first pressure reducing valve, 19-second pressure reducing valve, 2-dynamic dilution module, 21-first mass flow controller, 22-second mass flow controller, 23-static mixer, 31-six-way valve, 32-quartz inert capillary, 33-quadrupole mass spectrometer, 34-turbomolecular pump, 35-vortex pump, 36-T-connector, 41-third mass flow controller, 42-second back pressure valve, 43-mass flow meter. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0026] Example 1: like Figure 1 As shown, an online detection system for hydrogen leakage based on quadrupole mass spectrometry technology includes an intake module, a dynamic dilution module 2, a six-way valve quantitative injection module and a quadrupole mass spectrometry detection system arranged in sequence along the flow path, wherein the intake module includes a high-pressure intake module and an ambient air intake module, and the dynamic dilution module 2 includes a first mass flow controller 21, a second mass flow controller 22 and a static mixer 23; The high-pressure air intake module and the ambient air intake module are respectively connected to the air intake end of the second mass flow controller 22 through pipelines, and the air intake end of the first mass flow controller 21 is connected to the dilution gas 14.

[0027] The six-way valve quantitative injection module includes a six-way valve 31 , and the six-way valve 31 is provided with a quantitative loop with an injection volume of 10 mL.

[0028] Through the above technical solution, the detection system of the present application can detect gas samples of different pressures. When high-pressure gas needs to be detected, the high-pressure air inlet module is connected, and the high-pressure gas sample in the pipeline gas or high-pressure gas cylinder enters the first pressure reducing valve 18 through the high-pressure multi-position selection valve 13 to be reduced to 0.5 MPa (0.2~0.5 MPa), and then enters the quadrupole mass spectrometry detection system through the dynamic dilution module 2 to detect the hydrogen content.

[0029] When the ambient air needs to be detected, the ambient air inlet module is connected, the ambient air is pressurized to 0.3 MPa (0.2-0.5 MPa) by the diaphragm pump 15, the pressurization condition can be monitored by the digital pressure gauge 16 to ensure that the sample pressure and flow rate are consistent each time, and then the pressure is controlled and maintained by the first back pressure valve 17. The pressurized ambient air enters the four-pole mass spectrometry detection system through the dynamic dilution module 2, the six-way valve quantitative sampling module, and the four-pole mass spectrometry detection system to detect the hydrogen content.

[0030] The high-pressure gas inlet module and the ambient air inlet module can realize the sampling of samples with different pressures, and the detection system can reliably and quantitatively detect samples with different pressures in the pipeline gas, high-pressure gas cylinder and ambient air.

[0031] The four-pole mass spectrometry detection system comprises, in sequence along the flow path, a quartz inert capillary 32 and a four-pole mass spectrometer 33, a turbo molecular pump 34 and a scroll pump 35; a T-shaped joint 36 is arranged between the six-way valve 31 and the quartz inert capillary 32. Only a small amount of sample gas (about 20 mL / min according to the specific settings of the instrument) enters the vacuum chamber of the mass spectrometer for detection, and the excess sample gas is discharged through one port of the T-shaped joint 36.

[0032] The turbo molecular pump and the scroll pump 35 are used for vacuum pumping to realize efficient and stable high-vacuum environment and ensure the normal operation of the detector. Specifically, the scroll pump 35 is used as a front-stage pump to reduce the air pressure in the vacuum chamber from atmospheric pressure to a medium-vacuum range; the turbo molecular pump is used as a rear-stage pump to further reduce the vacuum degree to a super-high-vacuum state required for work, to transfer momentum to gas molecules through high-speed rotating blades, to reduce ion collision, background interference and molecular reaction, to improve the accuracy and resolution of mass spectrometry analysis, to shorten the vacuum establishment time, and to enhance the reliability of the system.

[0033] Further, the ports of the six-way valve 31 are connected with the dynamic dilution module 2, a carrier gas module, and a mass flow meter 43. The carrier gas module comprises, in sequence, a carrier gas and a third mass flow controller 41, the third mass flow controller 41 is used for controlling the flow rate of the carrier gas, and the flow rate is preferably 30 mL / min, the carrier gas is 99.9999% nitrogen gas without hydrogen impurities. The mass flow meter 43 is used for monitoring the flow rate of the sample.

[0034] Further, the second back pressure valve 42 and the digital pressure gauge 16 are arranged in the flow path between the dynamic dilution module 2 and the six-way valve 31, for controlling the sampling pressure and flow rate to ensure that the sampling pressure and flow rate are consistent each time.

[0035] Furthermore, heating devices are provided outside the six-way valve 31 and the quartz inert capillary 32. The quartz inert capillary 32 is heated to 120°C by the heating devices, and the temperature of the six-way valve 31 and the quantitative loop is set to 100°C (the temperature control range is 30-300°C) to ensure that no adsorption occurs to the sample.

[0036] Preferably, the detection conditions of the quadrupole mass spectrometer are as follows: the scanning mode is the multiple ion detection mode, the pumping speed of the molecular turbo pump is 60 L / s, the secondary electron multiplier (SEM) detector voltage is 1000 V, the emission current is 800 μA, the dwell time and interval time are 160 ms and 150 ms respectively, the electron energy is 70 eV, and the total system pressure is maintained at arrive The sample purge time (30 s) and injection time (30 s) were controlled by the computer program of the quadrupole mass spectrometer, and the flow rate of the gas standard substance cylinder and sample bottle was 30 mL / min.

[0037] Furthermore, a three-way joint is provided between the static mixer 23 and the first mass flow controller 21 and the second mass flow controller 22, and the outlet ends of the first mass flow controller 21 and the second mass flow controller 22 are respectively connected to the air inlet end of the static mixer 23 through the three-way joint.

[0038] Through the above technical solution, when it is necessary to dilute the high-concentration gas standard substance cylinder 12 online to obtain different concentrations, the gas standard substance cylinder 12 enters the static mixer 23 through the high-pressure multi-position selector valve and the second mass flow controller 22, and the other dilution gas 14 (99.9999% nitrogen) enters the static mixer 23 through the first mass flow controller 21. At this time, the high-concentration gas standard substance cylinder 12 is diluted by the dilution gas 14 and mixed evenly in the static mixer 23. Different concentrations can be obtained by mixing the dilution gas 14 with the high-precision dynamic dilution module 2 according to different dilution ratios.

[0039] Example 2: Based on the detection system of Example 1, an online hydrogen leak detection method based on quadrupole mass spectrometry technology includes the following steps: S1: Use high-purity nitrogen as the carrier gas and run under set conditions for more than 24 hours. Use the carrier gas to stabilize the flow path and check the air tightness of the system.

[0040] S2: Adjust the quadrupole mass spectrometer and set The scanned ion fragment M / Z (mass-to-charge ratio) = 2; in this embodiment, the total pressure of the detection system is set at mbar.

[0041] S3: obtaining hydrogen gas standard substances with different concentrations in the range of 0-200 ppm, ) response values, the step S3 includes sub-steps S31-S33: S31: using the gravimetric method to prepare 199.35 ppm of gas standard substance, S32: mixing the 199.35 ppm of gas standard substance with different dilution ratios by dilution gas (nitrogen) and a dynamic dilution module to obtain different concentrations, obtaining not less than 7 concentration points, each concentration point is continuously quantitatively loop sampled for more than 7 times, and different concentrations are respectively sampled and analyzed to obtain signal intensities, the signal intensity is the partial pressure value of hydrogen response, and the unit is mbar; S33: subtracting the corresponding baseline response value from the obtained signal intensity at different concentrations to obtain the absolute signal intensity value at different concentrations; S4: fitting a least square linear regression curve according to the different concentration values in S3 and the corresponding absolute intensity signal values, that is, obtaining a calibration curve, and simultaneously obtaining a linear regression equation: y = ax + b, wherein x is the absolute signal intensity value, the unit is mbar; y is the concentration value, the unit is ppm, a is the slope, and b is the intercept; S5: according to the formula , wherein is the standard deviation of the measurement values of 10 blank samples, s is the slope of the calibration curve in step S4, wherein the slope of the calibration curve is consistent with the slope of the linear regression equation, and the LOD is the detection limit, and the ppb level detection limit can be obtained through steps S3-S5; S6: the concentration value of the unknown sample can be calculated by substituting the absolute signal intensity value of the unknown hydrogen sample into the linear regression equation in S4.

[0042] The experimental data of step S3 is shown in Table 1, and 7 groups of samples with different concentrations are obtained.

[0043] Table 1: Calibration curve of 7 concentrations and absolute signal intensity values Fitting a least square linear regression curve according to the different concentration values of the seven groups of samples and the corresponding absolute intensity signal values, that is, obtaining a calibration curve. At the same time, a linear regression equation is obtained: ; Wherein x is the absolute signal intensity value, the unit is mbar; y is the concentration value, the unit is ppm.

[0044] The measurement values of 10 blank samples in step S5 are shown in Table 2, wherein the standard deviation formula is well known and is not described herein. The standard deviation of the measurement values of 10 blank samples is obtained by the standard deviation formula, As .

[0045] Table 2 Measurement data of 10 blank samples According to the formula , wherein, is the standard deviation of the measurement values of 10 blank samples, is ; s is the slope of the calibration curve in step S4, and is taken as , and the LOD (limit of detection) is 0.373 ppm.

[0046] The limit of detection is 0.373 ppm = 373 ppb, so that the limit of detection can reach the ppb level. At the same time, by increasing the total pressure, the sample amount of the instrument system can be further increased, and the limit of detection of the method can be improved The accuracy verification of the calibration curve in step S4 is as follows: 5.056 ppm Gas standard substance is used as the measured gas, and the corresponding signal intensity is obtained by sample analysis, and then the absolute signal intensity value is obtained. The absolute signal intensity value is brought into y of the linear regression equation, and the calibration curve calculation result is 5.190 ppm, and the relative deviation is 2.66%; 9.691 ppm Gas standard substance is used as the measured gas, and the hydrogen content is tested by the method, and the calibration curve calculation result is 9.383 ppm, and the relative deviation is 3.18%; 19.548 ppm Gas standard substance is used as the measured gas, and the hydrogen content is tested by the method, and the calibration curve calculation result is 19.750 ppm, and the relative deviation is 1.03%; It can be seen that the method of the present application is accurate and reliable.

[0047] The relative deviation calculation formula is as follows: ; In the formula, b (%) is the relative deviation, is the calibration curve calculation value, is the certified value of the standard substance. The linear range of the calibration curve is preferably: (2.072~199.35 ppm ).

[0048] The linear regression equation of the calibration curve in step S4 is: ; wherein = 0.9999, The value of the determination coefficient is in the range of 0 to 1, and in the linear regression equation of the present embodiment, the value is close to 1, indicating that the curve has a good fitting effect on the data.

[0049] Through the above detection method, the quadrupole mass spectrometry system has unprecedented sensitivity (detection limit = 0.373 ppm), speed (response time = 0.672 seconds), high precision (199.35 ppm, %RSD = 0.27%), excellent accuracy (relative deviation < 4%) and an expansion uncertainty of about 10% (corresponding to a 5.056 ppm hydrogen sample). The system has high selectivity, and other gases have no interference on the hydrogen component. The system breaks through the limitations of traditional online analysis methods, consumes only 10 mL of sample for analysis, and completes the analysis in 30 seconds, which is green and efficient. It can effectively provide real-time leak detection solutions for hydrogen filling stations and closed spaces.

[0050] Further, the system and method proposed by the present application are not only suitable for low-concentration hydrogen content measurement, but also suitable for high-concentration hydrogen content measurement. When measuring high-concentration hydrogen components, the detector of the quadrupole mass spectrometer can be a Faraday detector.

[0051] Further, by adding other M / Z values (mass-to-charge ratio values) in the software of the quadrupole mass spectrometer, simultaneous measurement of other gas components can also be realized, expanding the application range.

[0052] The above only describes the preferred embodiments of the present application, and it should be understood that the present application is not limited to the forms disclosed herein, and should not be considered as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concepts described herein by the above teachings or related art or knowledge. Any modification and change made by those skilled in the art without departing from the spirit and scope of the present application shall be within the protection scope of the appended claims of the present application.

Claims

1. An online hydrogen leak detection system based on quadrupole mass spectrometry technology, characterized by: The invention comprises an air intake module, a dynamic dilution module (2), a six-way valve quantitative injection module and a quadrupole mass spectrometry detection system arranged in sequence along the flow path, wherein the air intake module comprises a high-pressure air intake module and an ambient air air intake module, and the dynamic dilution module (2) comprises a first mass flow controller (21), a second mass flow controller (22) and a static mixer (23); The high-pressure air intake module and the ambient air intake module are respectively connected to the air intake end of the second mass flow controller (22) through pipelines, and the air intake end of the first mass flow controller (21) is connected to the dilution gas (14); The six-way valve quantitative injection module includes a six-way valve (31), and the six-way valve (31) is provided with a quantitative loop with a 10 mL injection volume; The quadrupole mass spectrometry detection system includes a quartz inert capillary (32) and a quadrupole mass spectrometry detector (33), a turbomolecular pump (34) and a vortex pump (35) arranged in sequence along the flow path; The interfaces of the six-way valve (31) are connected to the dynamic dilution module (2), the carrier gas module and the mass flow meter (43) through pipelines respectively, and the carrier gas module includes carrier gas and a third mass flow controller (41) in sequence.

2. The online hydrogen leak detection system based on quadrupole mass spectrometry technology according to claim 1, characterized in that: A three-way joint is provided between the static mixer (23) and the first mass flow controller (21) and the second mass flow controller (22), and the outlet ends of the first mass flow controller (21) and the second mass flow controller (22) are connected to the air inlet end of the static mixer (23) through the three-way joint.

3. The online hydrogen leak detection system based on quadrupole mass spectrometry technology according to claim 1, characterized in that: The high-pressure air inlet module comprises pipeline gas, a high-pressure sample bottle (11), a gas standard substance cylinder (12) and a high-pressure multi-position selector valve (13); the pipeline gas, the high-pressure sample bottle (11) and the gas standard substance cylinder (12) are respectively connected to the high-pressure multi-position selector valve (13) through pipelines; the high-pressure multi-position selector valve (13) is connected to the air inlet end of the second mass flow controller (22) through a pipeline; a first pressure reducing valve (18) is provided between the high-pressure multi-position selector valve (13) and the second mass flow controller (22).

4. The online hydrogen leak detection system based on quadrupole mass spectrometry technology according to claim 3, characterized in that: The ambient air intake module comprises ambient air, a diaphragm pump (15), a digital pressure gauge (16), and a first back pressure valve (17) in sequence, and the outlet end of the ambient air intake module is located at the rear end of the first pressure reducing valve (18).

5. The online hydrogen leak detection system based on quadrupole mass spectrometry technology according to claim 1, characterized in that: A second back pressure valve (42) and a digital pressure gauge (16) are provided in the flow path between the dynamic dilution module (2) and the six-way valve (31).

6. The online hydrogen leak detection system based on quadrupole mass spectrometry technology according to claim 5, characterized in that: The diluent gas (14) and the carrier gas both use 99.9999% nitrogen, which contains no hydrogen impurities. A second pressure reducing valve (19) is provided between the diluent gas (14) and the first mass flow controller (21).

7. The online hydrogen leak detection system based on quadrupole mass spectrometry technology according to claim 1, characterized in that: A T-shaped joint (36) is provided between the six-way valve (31) and the quartz inert capillary (32), one interface of the T-shaped joint (36) is used for exhaust, and heating devices are respectively provided outside the six-way valve (31) and the quartz inert capillary (32).

8. A method for online detection of hydrogen leaks based on quadrupole mass spectrometry, comprising the method for online detection of hydrogen leaks based on quadrupole mass spectrometry according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: High-purity nitrogen was used as the carrier gas and the operation was carried out under the set conditions for more than 24 h; S2: Adjust the quadrupole mass spectrometer and set Scanned ion fragments M / Z (mass-to-charge ratio) = 2; S3: Obtain hydrogen gas standard substances with different concentrations in the range of 0~200 ppm ( ) response value, the step S3 includes sub-steps S31-S33: S31: 199.35 ppm was obtained by gravimetric method Gas reference materials, S32: 199.35 ppm The gas standard substance is mixed with the diluent gas and the dynamic dilution module at different dilution ratios to obtain different concentrations, and no less than 7 concentration points are obtained. Each concentration point is sampled continuously for more than 7 times by quantitative loop injection. The signal intensity of different concentrations is obtained by injection analysis. The signal intensity is the partial pressure value of hydrogen response, and the unit is mbar; S33: subtracting the corresponding baseline response value from the obtained signal intensities of different concentrations to obtain absolute signal intensity values ​​of different concentrations; S4: Fit the least squares linear regression curve according to the different concentration values ​​in S3 and the corresponding absolute intensity signal values ​​to obtain the calibration curve, and at the same time obtain the linear regression equation: y = ax + b, where x is the absolute signal intensity value in mbar; y is the concentration value in ppm, a is the slope, and b is the intercept; S5: According to the formula , where is the standard deviation of the measurement values ​​of 10 blank samples, s is the slope of the calibration curve in step S4, wherein the slope of the calibration curve is consistent with the slope of the linear regression equation, LOD is the detection limit, and the ppb level detection limit can be obtained through steps S3 to S5; S6: Based on the absolute signal intensity value of the unknown hydrogen sample, the concentration value of the unknown sample can be calculated by substituting it into the linear regression equation in S4.

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