Liquid hydrogen quality traceability system and method

Abstract

The present invention relates to the field of measurement technology, and in particular to a liquid hydrogen quality traceability system and method, comprising: S1: passing the liquid hydrogen to be measured into a liquid storage container through a pipeline, wherein the temperature of the pipeline is kept below the boiling point of hydrogen by a refrigeration system, and the tare weight of the liquid storage container is weighed to obtain the liquid hydrogen mass m L S2: Turn off the refrigeration system, wait until the pipeline temperature rises above the boiling point of hydrogen, then use high-purity inert gas to blow the vaporized residual hydrogen in the pipeline into the gas storage container, and record the mass of the high-purity inert gas introduced m a , using gas chromatography to measure the molar percentage w of the high-purity gas; S3: calculate the mass m of the residual hydrogen in the pipeline g , the total mass of the liquid hydrogen to be measured is obtained as m=m L +m g This method can trace the quality of liquid hydrogen with high precision and small systematic error, solving the long-standing problem of difficult liquid hydrogen quality traceability. It can very accurately trace the quality of hydrogen refueling machines, hydrogen refueling guns or liquid hydrogen pipelines.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and in particular to a liquid hydrogen quality tracing system and method. Background Art

[0002] Hydrogen boasts a wide range of sources, is clean and efficient, and has diverse applications. Hydrogen storage and transportation are key factors in the development of the hydrogen energy industry. Hydrogen storage is typically achieved in high-pressure gas, cryogenic liquid, solid, or liquid forms. However, in terms of energy density, economies of scale, and convenience, cryogenic liquid hydrogen offers significant advantages over gaseous hydrogen.

[0003] Currently, liquid hydrogen is primarily used in the military and aerospace sectors. With the increasing adoption of proton exchange membrane fuel cell vehicles (PEMFCs), its civilian application is rapidly expanding. Accurately measuring and tracing the quality of liquid hydrogen is crucial. Existing research on liquid hydrogen traceability is limited, and mass methods similar to those used for gaseous hydrogen are generally used. In theory, directly measuring liquid hydrogen mass with precision instruments is the most accurate. However, in practice, high-precision instruments require storage under specific conditions, such as constant temperature and humidity. Direct connection to the hydrogen source (such as a hydrogenation gun or liquid hydrogen pipeline) is not possible. A transmission line is required to connect the hydrogen source to the mass measurement instrument. Even if the line length is minimized, it still requires at least 2-3 meters. This line can result in small amounts of residual liquid hydrogen, leading to inaccurate measurement results. Current detection methods often ignore these trace amounts of residual hydrogen in the line. Chinese patent CN114087539A discloses a liquid hydrogen flow standard device based on dynamic and static weighing methods. This patent can more accurately measure the actual flow rate of liquid hydrogen by measuring the dynamic mass flow rate and the static mass flow rate and performing a weighted average calculation on the two mass flows. However, this method does not take into account the residual hydrogen in the pipeline. Instead, the residual hydrogen is emptied after each measurement. Such measurement results are bound to have systematic errors.

[0004] Based on this, this patent combines the quality traceability methods of liquid hydrogen and gaseous hydrogen, and discloses a liquid hydrogen quality traceability device and method based on the coupling of weighing method and chromatographic analysis method. Through high-precision balance weighing and gas chromatography standard material comparison analysis, the accuracy of liquid hydrogen quality traceability is greatly improved. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a method and apparatus for tracing the mass of liquid hydrogen, so as to at least achieve more accurate mass tracing of liquid hydrogen and trace the mass of liquid hydrogen to the SI unit kg.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] The hydrogen quality traceability method includes the following steps:

[0008] S1: The liquid hydrogen to be tested is passed into a liquid storage container through a pipeline. The temperature of the pipeline is kept below the boiling point of hydrogen by a refrigeration system. The tare weight of the liquid storage container is weighed to obtain the mass m of liquid hydrogen. L ;

[0009] S2: Turn off the refrigeration system, wait until the pipeline temperature rises above the boiling point of hydrogen, then use high-purity inert gas to blow the vaporized residual hydrogen in the pipeline into the gas storage container, and record the mass of the high-purity inert gas introduced m a , measuring the molar percentage w of the high-purity inert gas by gas chromatography;

[0010] S3: Calculate the mass m of residual hydrogen in the pipeline g , the total mass of the liquid hydrogen to be measured is m=m L +m g .

[0011] Furthermore, the mass of the residual hydrogen m g The calculation method is:

[0012] Calculate the mass of residual high-purity inert gas in the pipeline: m b = kπR 2 Lρ;

[0013] Calculate the mass of the high-purity inert gas in the gas storage container: m1=m a -m b ;

[0014] Calculate the molar amount of high-purity inert gas in the gas storage container: n1=m1 / M;

[0015] The mass of residual hydrogen m g =2.016*n g =2.016*(n1 / w-n1);

[0016] In the formula, k is the ratio of the pressure P of the high-purity inert gas to the standard pressure P0, k=P / P0; R is the inner diameter of the pipeline; L is the length of the pipeline; ρ is the density of the high-purity inert gas at normal pressure; and M is the relative molecular mass of the high-purity inert gas.

[0017] A liquid hydrogen quality traceability device, comprising a liquid inlet 1, a liquid hydrogen pipeline 2, a liquid hydrogen container 4, a weighing device 5, a hydrogen pipeline 6, a gas phase detection device 7, a high-purity gas pipeline 8, a gas storage container 17, and a refrigeration device 18;

[0018] The liquid inlet 1, the liquid hydrogen pipeline 2 and the high-purity gas pipeline 8 are connected via a first three-way valve 12;

[0019] The other end of the liquid hydrogen pipeline 2, the hydrogen pipeline 6 and the liquid hydrogen container 4 are connected via a second three-way valve 13;

[0020] The other end of the hydrogen pipeline 6, the gas storage container 17 and the gas phase detection device 7 are connected in sequence;

[0021] The refrigeration device 18 is used to control the temperature of the liquid hydrogen pipeline 2;

[0022] The weighing device 5 is used to weigh the weight of the liquid hydrogen container 4;

[0023] The hydrogen pipeline 6 is provided with a first one-way valve 14 facing the gas storage container 17;

[0024] The high-purity gas pipeline 8 is provided with a flow meter 15 and a second one-way valve 16 facing the first three-way valve 12;

[0025] The flow meter 15 is used to measure the mass of the gas passing through the second one-way valve 16;

[0026] The openings of the liquid hydrogen container 4 and the gas storage container 17 are provided with valves for controlling the inflow and outflow of substances.

[0027] Furthermore, the refrigeration device 18 is composed of a liquid helium reflux pipe 9, a liquid helium cooling pipe 10, a refrigerator 3 and a liquid helium outlet pipe 11 connected in sequence;

[0028] The liquid helium cooling pipe wraps the exterior of the liquid hydrogen pipe 2, the first three-way valve 12 and the second three-way valve 13;

[0029] The interior of the refrigeration device is filled with liquid helium.

[0030] Furthermore, the gas phase detection device 7 is a gas chromatograph.

[0031] Furthermore, the gas phase detection device 7 is connected to a gas standard substance.

[0032] The method for using the device comprises the following steps:

[0033] Step 1: Open the refrigerator 3 to reduce the temperature in the liquid hydrogen pipeline 2 to below the boiling point of hydrogen; open the first three-way valve 12 to connect only the liquid inlet 1 with the liquid hydrogen pipeline 2; open the second three-way valve 13 to connect only the liquid hydrogen pipeline 2 with the liquid hydrogen container 4;

[0034] Step 2: Open the valve of the liquid hydrogen container 4, and let the liquid hydrogen to be tested enter the liquid hydrogen container 4 from the liquid inlet 1. Then, close the valve of the liquid hydrogen container 4; measure the tare weight m of the liquid hydrogen container 4 by the weighing device 5. L ;

[0035] Step 3: Control the first three-way valve 12 to connect only the high-purity gas pipeline 8 with the liquid hydrogen pipeline 2; control the second three-way valve 13 to connect only the liquid hydrogen pipeline 2 with the hydrogen pipeline 6; close the refrigerator 3 to increase the temperature in the liquid hydrogen pipeline 2 to above the boiling point of hydrogen, and then pressurize high-purity inert gas into the inlet of the high-purity gas pipeline 8 under high pressure;

[0036] Step 4: Open the valve of the gas storage container 17, wait for the high-purity inert gas to blow the residual hydrogen in the pipeline and valve into the gas storage container 17, and then close the valve of the gas storage container 17; record the reading of the flow meter 15 m a ;

[0037] Step 5: After the hydrogen and high-purity inert gas in the gas storage container 17 are evenly mixed, the valve of the gas storage container 17 is opened to allow the mixture of hydrogen and high-purity inert gas to pass into the gas phase detection device 7 for analysis, and the molar percentage w of the high-purity inert gas in the mixture is measured;

[0038] The total mass m of the liquid hydrogen to be measured is calculated by the following formula:

[0039] Mass of high-purity inert gas sealed in the pipeline m b = kπR 2 Lρ;

[0040] The mass of high-purity inert gas in the mixed gas is m1=m a -m b ;

[0041] The molar amount of high-purity inert gas in the mixed gas is n1=m1 / M;

[0042] The mass m of hydrogen in the mixed gas g =2.016*n g =2.016*(n1 / w-n1);

[0043] The total mass of liquid hydrogen to be measured is m=m L +m g ;

[0044] In the formula, k is the ratio of the pressure P of the high-purity gas to the standard pressure P0, k=P / P0; R is the inner diameter of the liquid hydrogen pipeline 2, the high-purity gas pipeline 8 and the hydrogen pipeline 6; L is the length of the pipeline between the first one-way valve 14 and the second one-way valve 16 in the path through which the high-purity inert gas flows; ρ is the density of the high-purity inert gas at normal pressure; and M is the relative molecular mass of the high-purity inert gas.

[0045] In some preferred embodiments, the gas phase detection device includes a gas chromatograph, and the detector used may be a thermal conductivity detector TCD, a helium ionization detector PDHID, a plasma emission detector PED, a dielectric barrier discharge detector BID, etc. (when the detector is PDHID, PED or BID, helium cannot be introduced).

[0046] In some preferred embodiments, the weighing device 5 is a high-precision balance with a tare function, and the weighing sensitivity is 0.000001 g. Different sensitivities can be selected according to the weighing accuracy.

[0047] The high-purity inert gas should be a gas type that can be analyzed by the detection device 7;

[0048] In some preferred embodiments, the high-purity inert gas is any one of helium, nitrogen, argon, and carbon dioxide.

[0049] In some preferred embodiments, the liquid hydrogen container 4 and the gas storage container 17 need to be evacuated before use; specifically, after being evacuated by a molecular turbo pump equipped with an online mass spectrometer, the vacuum degree is less than 0.001 mbar or lower pressure, and the online mass spectrometry analysis shows that there is no air residue and no characteristic fragment ions of nitrogen and oxygen are detected, which is considered to be complete.

[0050] Furthermore, when the inner diameters of the liquid hydrogen pipeline 2, the high-purity gas pipeline 8, and the hydrogen pipeline 6 are inconsistent, m b =kπρ(R1 2 L1+R2 2 L2+R3 2 L3);

[0051] R1, R2 and R3 are the inner diameters of the liquid hydrogen pipeline 2, the high-purity gas pipeline 8 and the hydrogen pipeline 6 respectively;

[0052] The L1, L2 and L3 are the lengths of the high-purity inert gas flowing through the liquid hydrogen pipeline 2, the high-purity gas pipeline 8 and the hydrogen pipeline 6 respectively.

[0053] It is worth noting that, with the exception of the liquid hydrogen pipeline 2, which is at least 2 meters long, the lengths of the remaining pipelines involved in the present invention, including the liquid hydrogen pipeline 2, the high-purity gas pipeline 8, and the hydrogen pipeline 6, can be adjusted based on practical circumstances. The positions of the first and second one-way valves 14, 16 on the high-purity gas pipeline 8 and hydrogen pipeline 6 can also be adjusted based on practical circumstances. Theoretically, the closer the first one-way valve 14 is to the flowmeter 15 and the second one-way valve is to the gas storage container 17, the smaller the resulting error.

[0054] Furthermore, the device also has automatic control and communication functions. Specifically, the liquid hydrogen container 4 is also equipped with automatic monitoring and communication equipment, and the first three-way valve 12 and the second three-way valve 13 are equipped with automatic control and signal receiving equipment. When the automatic monitoring equipment detects that the liquid volume in the liquid hydrogen container 4 reaches 80%, the communication equipment sends a command to the signal receiving equipment of the first three-way valve 12 and the second three-way valve 13. The automatic control equipment controls the liquid inlet 1 of the first three-way valve 12 to close, and one side of the high-purity gas pipeline 8 to open. At the same time, the liquid hydrogen container 4 side of the second three-way valve 13 is closed, and the hydrogen pipeline 6 side is opened, thereby realizing automatic control of the detection process.

[0055] The beneficial effects of the present invention are:

[0056] The present invention combines a precision balance weighing method for liquid hydrogen mass with a chromatographic analysis method for determining the value of residual liquid hydrogen in the pipeline using a standard substance. The Stirling liquid helium cooling design allows the liquid hydrogen to remain in a uniform liquid state during its circulation in the pipeline. The low-flash rate storage tank and low-sensitivity balance ensure the accuracy of liquid hydrogen weighing. The residual liquid hydrogen in the pipeline is purged and collected using external high-purity gas, and accurately quantified using a standard substance coupled with a gas chromatograph. This combination effectively reduces the systematic error in liquid hydrogen traceability, enabling highly accurate quantitative analysis and quality traceability of liquid hydrogen from different sources, such as hydrogenators, hydrogenation guns, and hydrogen production plants, ensuring the accuracy and fairness of the measurement values during the liquid hydrogen trade handover process. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Schematic diagram of the process of the liquid hydrogen quality traceability method of the present invention;

[0058] Figure 2 This is a structural diagram of the liquid hydrogen traceability device of the present invention;

[0059] In the figure, 1. liquid inlet; 2. liquid hydrogen pipeline; 3. refrigerator; 4. liquid hydrogen container; 5. weighing device; 6. hydrogen pipeline; 7. gas phase detection device; 8. high-purity gas pipeline; 9. liquid helium reflux pipeline; 10. liquid helium cooling pipeline; 11. liquid helium outlet pipeline; 12. first three-way valve; 13. second three-way valve; 14. first one-way valve; 15. flow meter; 16. second one-way valve; 17. gas storage container; 18. refrigeration device. DETAILED DESCRIPTION

[0060] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0061] like Figure 2As shown, this embodiment provides a traceability device for detecting the quality of liquid hydrogen, including a liquid inlet 1, a liquid hydrogen pipeline 2, a refrigeration device 18 (including a liquid helium outlet pipeline 11, a liquid helium cooling pipeline 10, a liquid helium reflux pipeline 9 and a refrigerator 3), a liquid hydrogen container 4, a weighing device 5, a hydrogen pipeline 6, a gas phase detection device 7, a high-purity gas pipeline 8, a first three-way valve 12, a second three-way valve 13, a first one-way valve 14, a flow meter 15, a second one-way valve 16 and a gas storage container 17;

[0062] The first three-way valve 12 and the second three-way valve 13 are low-temperature solenoid valves (USA NOTON Norton), made of stainless steel 304 / 316, with a working pressure of (0.1-16.0) MPa);

[0063] The gas phase detection device 7 is: chromatograph-Agilent7890, equipped with TCD, PDHID, PED and BID detectors, and the chromatographic column is a capillary column filled with 5A molecular sieve;

[0064] The refrigerator 3 is: refrigerator - American ORTEC, model CryoTel;

[0065] The liquid hydrogen container 4 is a low-temperature liquid hydrogen storage tank made of carbon fiber composite material.

[0066] The refrigeration device 18 is composed of a liquid helium reflux pipe 9, a liquid helium cooling pipe 10, a refrigerator 3 and a liquid helium outlet pipe 11 connected in sequence;

[0067] The refrigerator is a Stirling refrigerator.

[0068] The liquid inlet 1, the liquid hydrogen pipeline 2 and the high-purity gas pipeline 8 are connected via a first three-way valve 12;

[0069] The liquid hydrogen pipeline 2, the hydrogen gas pipeline 6 and the liquid hydrogen container 4 are connected via a second three-way valve 13;

[0070] The refrigeration device wraps the exterior of the liquid hydrogen pipeline 2 , the first three-way valve, and the second three-way valve.

[0071] The hydrogen pipeline 6 connects the liquid hydrogen container 4 and the gas phase detection device 7;

[0072] The hydrogen pipeline 6 is provided with a first one-way valve 14;

[0073] The gas phase detection device includes a gas chromatograph.

[0074] The liquid hydrogen container 4 is placed on the weighing device 5;

[0075] The weighing device 5 is a high-precision balance with a tare function, and its sense of measurement is 0.00001 g.

[0076] The liquid hydrogen container is a liquid hydrogen cylinder with a vent valve at the bottle mouth;

[0077] The inner diameter R of the liquid hydrogen pipeline 2, the high-purity gas pipeline 8, and the hydrogen pipeline 6 is 3 / 4 inch (19.05 mm);

[0078] The high-purity gas pipeline 8 is provided with a flow meter 15 and a second one-way valve 16 .

[0079] The hydrogen pipeline 6 is provided with a gas storage container 17;

[0080] The gas storage container 17 is a gas storage cylinder, and the cylinder mouth is provided with a vent valve;

[0081] The gas phase detection device 7 is connected to hydrogen and nitrogen standard substances.

[0082] Example 2

[0083] The performance of the hydrogenation gun was tested using the apparatus described in Example 1. First, the entire device path was evacuated using a molecular turbopump equipped with an online mass spectrometer to a vacuum degree of less than 0.001 mbar. After online mass spectrometry analysis revealed no residual air, specifically, no characteristic fragment ions of nitrogen and oxygen were detected, the following method was followed:

[0084] S1: Close the first one-way valve 14 and the second one-way valve 16, and open the refrigerator 3, the first three-way valve 12 and the second three-way valve 13;

[0085] S2: When the temperature in the liquid hydrogen pipeline 2 drops below the boiling point of hydrogen, the liquid hydrogen to be tested is introduced from the liquid inlet 1 using a hydrogenation gun at a flow rate of 200 g / min, and the tare weight m of the liquid hydrogen container 4 is measured by the weighing device 5. L =1285.29382g, at this time the flow rate displayed by the hydrogenation gun is 1297.17 g;

[0086] S3: Close the refrigerator 3, and when the temperature in the liquid hydrogen pipeline 2 rises to above the boiling point of hydrogen, open the first one-way valve 14 and the second one-way valve 16, and pressurize high-purity nitrogen gas into the inlet of the high-purity gas pipeline 8 under high pressure;

[0087] S4: After the high-purity nitrogen gas blows the residual hydrogen in the pipeline and valve into the gas storage container 17; close the first one-way valve 14 and the second one-way valve 16; record the reading of the flow meter 15 m a =58.27 g;

[0088] S5: Open the vent valve of the gas storage container 17 to allow the mixture of hydrogen and high-purity nitrogen to pass into the detection device 7. Use the gas standard substance external standard method to measure the molar percentage of high-purity inert gas in the mixture, w = 90.16%;

[0089] The total mass m of the liquid hydrogen to be measured is calculated by the following formula:

[0090] Mass of high-purity inert gas sealed in the pipeline m b = kπR 2 Lρ;

[0091] The mass of high-purity inert gas in the mixed gas is m1=m a -m b ;

[0092] The molar amount of high-purity inert gas in the mixed gas is n1=m1 / 28;

[0093] In the mixed gas, R is the inner diameter of the pipeline, R=19.05 mm;

[0094] The mass m of hydrogen in the mixed gas g =2.016*n g =2.016*(n1 / w-n1);

[0095] Wherein, k is the ratio of the pressure P of the high-purity gas to the standard pressure P0, k=P / P0=5.37; R is the inner diameter of the liquid hydrogen pipeline 2, the high-purity gas pipeline 8 and the hydrogen pipeline 6; L=2.50m is the length of the pipeline between the first one-way valve 14 and the second one-way valve 16 in the flow path of the high-purity inert gas; ρ=1.25g / L is the density of the high-purity nitrogen under standard conditions.

[0096] Calculation shows that the total mass of liquid hydrogen to be measured is m=m L +m g =1285.29382+10.99723=1296.29105 g.

[0097] Comparative Example

[0098] The hydrogenation gun to be tested was directly connected to the liquid hydrogen cylinder via a 2.50m pipe. A refrigeration unit was used to maintain the pipe temperature below the boiling point of hydrogen at the current pressure. An equal amount of liquid hydrogen was added through the gun and tested using the same high-precision balance. The mass of the liquid hydrogen, m', was measured to be 1285.41342g.

[0099] It can be seen that the residual hydrogen mass in the pipeline accounts for 10.99723 / 1296.29105=0.848%. In high-precision detection or bulk liquid hydrogen trade, this part of the hydrogen mass cannot be ignored. Precision measurement ensures the accuracy of liquid hydrogen quantity traceability and guarantees the fairness of trade handover.

[0100] The foregoing description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. Liquid hydrogen quality traceability method, characterized by: The following steps are involved: S1: The liquid hydrogen to be tested is passed into a liquid storage container through a pipeline. The temperature of the pipeline is kept below the boiling point of hydrogen by a refrigeration system. The tare weight of the liquid storage container is weighed to obtain the mass m of liquid hydrogen. L ; S2: Turn off the refrigeration system, wait until the pipeline temperature rises above the boiling point of hydrogen, then use high-purity inert gas to blow the vaporized residual hydrogen in the pipeline into the gas storage container, and record the mass of the high-purity inert gas introduced m a , measuring the molar percentage w of the high-purity inert gas by gas chromatography; S3: Calculate the mass m of residual hydrogen in the pipeline g , the total mass of the liquid hydrogen to be measured is m=m L +m g ; The mass of residual hydrogen m g The calculation method is: Calculate the mass of residual high-purity inert gas in the pipeline: m b = kπR 2 Lρ; Calculate the mass of the high-purity inert gas in the gas storage container: m1=m a -m b ; Calculate the molar amount of high-purity inert gas in the gas storage container: n1=m1 / M; The mass of residual hydrogen m g =2.016*n g =2.016*(n1 / w-n1); In the formula, k is the ratio of the pressure P of the high-purity inert gas to the standard pressure P0, k=P / P0; R is the inner diameter of the pipeline; L is the length of the pipeline; ρ is the density of the high-purity inert gas at normal pressure; and M is the relative molecular mass or relative atomic mass of the high-purity inert gas.

2. Liquid hydrogen quality traceability equipment, characterized by: It includes a liquid inlet (1), a liquid hydrogen pipeline (2), a liquid hydrogen container (4), a weighing device (5), a hydrogen pipeline (6), a gas phase detection device (7), a high-purity gas pipeline (8), a gas storage container (17) and a refrigeration device (18); The liquid inlet (1), the liquid hydrogen pipeline (2) and the high-purity gas pipeline (8) are connected via a first three-way valve (12); The other end of the liquid hydrogen pipeline (2), the hydrogen pipeline (6) and the liquid hydrogen container (4) are connected via a second three-way valve (13); The other end of the hydrogen pipeline (6), the gas storage container (17) and the gas phase detection device (7) are connected in sequence; The refrigeration device (18) is used to control the temperature of the liquid hydrogen pipeline (2); The weighing device (5) is used to weigh the weight of the liquid hydrogen container (4); The hydrogen pipeline (6) is provided with a first one-way valve (14) facing the gas storage container (17); The high-purity gas pipeline (8) is provided with a flow meter (15) and a second one-way valve (16) facing the first three-way valve (12); The flow meter (15) is used to measure the mass of the gas passing through the second one-way valve (16); Valves for controlling the inflow and outflow of substances are provided at the openings of the liquid hydrogen container (4) and the gas storage container (17).

3. The device according to claim 2, characterized in that: The refrigeration device (18) is composed of a liquid helium reflux pipe (9), a liquid helium cooling pipe (10), a refrigerator (3) and a liquid helium outlet pipe (11) connected in sequence; The liquid helium cooling pipeline wraps the exterior of the liquid hydrogen pipeline (2), the first three-way valve (12) and the second three-way valve (13); The interior of the refrigeration device is filled with liquid helium.

4. The device according to claim 3, characterized in that: The gas phase detection device (7) is a gas chromatograph.

5. The device according to claim 4, characterized in that: The gas chromatograph is connected to a gas standard substance.

6. The method for using the device according to any one of claims 3 to 5, characterized in that: The following steps are involved: Step 1: turning on the refrigerator (3) to reduce the temperature in the liquid hydrogen pipeline (2) to below the boiling point of hydrogen; Opening the first three-way valve (12) allows only the liquid inlet (1) to communicate with the liquid hydrogen pipeline (2); opening the second three-way valve (13) allows only the liquid hydrogen pipeline (2) to communicate with the liquid hydrogen container (4); Step 2: Open the valve of the liquid hydrogen container (4), introduce the liquid hydrogen to be tested from the liquid inlet (1), and part of the liquid hydrogen to be tested enters the liquid hydrogen container (4), and then close the valve of the liquid hydrogen container (4); measure the tare weight m of the liquid hydrogen container (4) by the weighing device (5) L ; Step 3: Control the first three-way valve (12) so that only the high-purity gas pipeline (8) is connected to the liquid hydrogen pipeline (2); control the second three-way valve (13) so that only the liquid hydrogen pipeline (2) is connected to the hydrogen pipeline (6); close the refrigerator (3) to increase the temperature in the liquid hydrogen pipeline (2) to above the boiling point of hydrogen, and then pressurize high-purity inert gas from the inlet of the high-purity gas pipeline (8) under high pressure; Step 4: Open the valve of the gas storage container (17), wait for the high-purity inert gas to blow the residual hydrogen in the pipeline and valve into the gas storage container (17), and then close the valve of the gas storage container (17); record the reading of the flow meter (15) m a ; Step 5: After the hydrogen and high-purity inert gas in the gas storage container (17) are uniformly mixed, the valve of the gas storage container (17) is opened to allow the mixture of hydrogen and high-purity inert gas to pass into the gas phase detection device (7) for analysis, and the molar percentage w of the high-purity inert gas in the mixture is measured; The total mass m of the liquid hydrogen to be measured is calculated by the following formula: Mass of high-purity inert gas sealed in the pipeline m b = kπR 2 Lρ; The mass of high-purity inert gas in the mixed gas is m1=m a -m b ; The molar amount of high-purity inert gas in the mixed gas is n1=m1 / M; The mass m of hydrogen in the mixed gas g =2.016*n g =2.016*(n1 / w-n1); The total mass of liquid hydrogen to be measured is m=m L +m g ; In the formula, k is the ratio of the pressure P of the high-purity gas to the standard pressure P0, k=P / P0; R is the inner diameter of the liquid hydrogen pipeline (2), the high-purity gas pipeline (8) and the hydrogen pipeline (6); L is the length of the pipeline between the first one-way valve (14) and the second one-way valve (16) in the path through which the high-purity inert gas flows; ρ is the density of the high-purity inert gas at normal pressure; and M is the relative molecular mass of the high-purity inert gas.

7. The method of use according to claim 6, characterized in that: When the inner diameters of the liquid hydrogen pipeline (2), the high-purity gas pipeline (8), and the hydrogen pipeline (6) are inconsistent, m b = kπρ(R1 2 L1+R2 2 L2+R3 2 L3); R1, R2 and R3 are the inner diameters of the liquid hydrogen pipeline (2), the high-purity gas pipeline (8) and the hydrogen pipeline (6), respectively; L1, L2 and L3 are the lengths of the high-purity inert gas flowing through the liquid hydrogen pipeline (2), the high-purity gas pipeline (8) and the hydrogen pipeline (6), respectively.

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