Ortho-parahydrogen and parahydrogen-ortho-hydrogen catalytic conversion test system

Abstract

The invention provides an ortho-parahydrogen and parahydrogen-ortho-hydrogen catalytic conversion test system. A compression assembly of the ortho-parahydrogen and parahydrogen-ortho-hydrogen catalytic conversion test system is used for compressing normal-temperature hydrogen; the partial heat exchanger is used for carrying out step-by-step cooling on the hydrogen to obtain liquid hydrogen at a set temperature; a refrigerant medium of the heat exchanger comprises backflow liquid hydrogen and a refrigerant introduced from the outside; the liquid hydrogen flows through part of the heat exchangers, the liquid hydrogen is heated and rewarmed step by step through the hydrogen flowing through the heat exchangers, the hydrogen at the set temperature is obtained, the rewarmed hydrogen circularly flows back to the compression assembly, and closed circulation of the hydrogen is completed; the branch pipeline assembly comprises a plurality of branch pipelines, and each branch pipeline is used for collecting hydrogen or liquid hydrogen at the corresponding position and sending the hydrogen or liquid hydrogen into a gas chromatograph for analysis.

Description

Technical Field

[0001] This application relates to the technical field of test and analysis equipment, and particularly to a test system for ortho-para hydrogen and para-ortho hydrogen catalytic conversion. Background Art

[0002] Liquid hydrogen is considered a potential large-scale energy storage substance and form for future renewable energy development due to its high volumetric energy density, purity, cleanliness, and renewability. However, the energy consumption in the hydrogen liquefaction process accounts for about 40%-50% of its own calorific value, which limits the energy transfer efficiency of liquid hydrogen as an energy storage substance. In addition to further optimizing the hydrogen liquefaction process and improving the liquefaction efficiency, how to utilize the cold energy stored in liquid hydrogen and recover the work input during the liquefaction process is also an important way to improve the energy storage efficiency of liquid hydrogen.

[0003] For hydrogen under thermodynamic equilibrium conditions (equilibrium hydrogen), the component concentrations of ortho-hydrogen molecules and para-hydrogen molecules only vary with temperature. At room temperature, equilibrium hydrogen consists of approximately 75% ortho-hydrogen and 25% para-hydrogen; at 77 K, equilibrium hydrogen consists of approximately 50% ortho-hydrogen and 50% para-hydrogen; at 20 K, equilibrium hydrogen contains more than 99% para-hydrogen. However, due to the slow reaction kinetics, the spontaneous conversion process of ortho-hydrogen to para-hydrogen is relatively long. Without a catalyst, after undergoing the normal liquefaction process, the liquid hydrogen product still contains a relatively high concentration of ortho-hydrogen. During long-term storage, the spontaneous ortho-para hydrogen conversion is accompanied by a strong exothermic process, with a reaction heat of approximately 527 kJ / kg, which is higher than the latent heat of liquid hydrogen of 446 kJ / kg. This will cause excessive evaporation of liquid hydrogen, resulting in losses and even potential hazards.

[0004] Under the application requirements of hydrogen liquefaction, the ortho-para hydrogen catalytic reaction has been relatively well studied. With the in-depth research, researchers have also started to pay attention to the reverse process of this reaction. For example, at the application ends such as storage tanks and hydrogen fuel cells, along with the rewarming process, the slow para-ortho hydrogen reaction will occur. Accelerating this reaction to reach equilibrium can recover additional cold energy for use in storage tank insulation or the thermal management of hydrogen fuel cells. This is also an effective way to utilize the cold energy of liquid hydrogen and improve the energy storage efficiency of liquid hydrogen.

[0005] Currently, most of the existing test devices for ortho-para hydrogen catalytic conversion are designed as open systems. During the test process, an external hydrogen source needs to be connected, and the hydrogen needs to be discharged immediately after the test is completed. Such a process not only causes waste of hydrogen and cold energy, but also cannot achieve continuous testing due to limitations such as insufficient gas source, and cannot well analyze the contents of ortho-hydrogen and para-hydrogen, thus prolonging the test cycle. Summary of the Invention

[0006] The purpose of the embodiments of this application is to provide a test system for ortho-para hydrogen and para-ortho hydrogen catalytic conversion.

[0007] Embodiments of the present application adopt the following technical solutions: A normal - para hydrogen and para - normal hydrogen catalytic conversion test system, comprising: A compression assembly for compressing hydrogen at room temperature; A heat exchanger assembly, which includes a plurality of heat exchangers that are interconnected; one of the heat exchangers is connected to the compression assembly to receive the hydrogen that has been compressed and heated by the compression assembly; some of the heat exchangers are used to cool the hydrogen step by step to obtain liquid hydrogen at a set temperature; the refrigerant medium of the heat exchanger includes the refluxed liquid hydrogen and the externally introduced refrigerant; the liquid hydrogen flows through some of the plurality of heat exchangers to be heated and reheated step by step by the hydrogen flowing through the heat exchanger to obtain hydrogen at a set temperature, and the reheated hydrogen circulates back to the compression assembly to complete the closed - loop cycle of hydrogen; at least some of the plurality of heat exchangers are provided with normal - para hydrogen conversion reaction catalysts and para - normal hydrogen conversion reaction catalysts; A liquid hydrogen storage tank connected to another heat exchanger among the plurality of heat exchangers to store liquid hydrogen; A branch pipeline assembly, which includes a plurality of branch pipelines, and one end of each branch pipeline is respectively connected to the hydrogen outlet of the heat exchanger, the liquid hydrogen outlet of the heat exchanger, and the liquid hydrogen storage tank to collect hydrogen or liquid hydrogen at the corresponding positions; A gas chromatograph connected to the other end of each branch pipeline to analyze the hydrogen or liquid hydrogen from each branch pipeline, and thereby determine the concentrations of normal hydrogen and para hydrogen during the conversion process of normal hydrogen and para hydrogen at different temperatures.

[0008] In some embodiments, the heat exchanger assembly includes a first - stage heat exchanger, a second - stage heat exchanger, a third - stage heat exchanger, a fourth - stage heat exchanger, and a fifth - stage heat exchanger; the third - stage heat exchanger and the fourth - stage heat exchanger are the test - section heat exchangers for the normal - para hydrogen catalytic reaction and the para - normal hydrogen catalytic reaction; the fifth - stage heat exchanger is the equilibrium - section heat exchanger for the normal - para hydrogen catalytic reaction, and the second - stage heat exchanger is the equilibrium - section heat exchanger for the para - normal hydrogen catalytic reaction; The first - stage heat exchanger, the third - stage heat exchanger, and the fourth - stage heat exchanger all include a first flow channel, a second flow channel, and a third flow channel; the second - stage heat exchanger includes a second flow channel and a third flow channel; the fifth - stage heat exchanger includes a first flow channel and a third flow channel; The hydrogen compressed and heated by the compression assembly is successively cooled step by step through the first flow channel of the first - stage heat exchanger, the first flow channel of the third - stage heat exchanger, the first flow channel of the fourth - stage heat exchanger, and the first flow channel of the fifth heat exchanger to obtain liquid hydrogen, and the first flow channel of the fifth heat exchanger transports the liquid hydrogen to the liquid hydrogen storage tank; The liquid hydrogen in the liquid hydrogen storage tank is heated and rewarmed successively through the second flow path of the fourth-stage heat exchanger, the second flow path of the third-stage heat exchanger, the second flow path of the second-stage heat exchanger, and the second flow path of the first-stage heat exchanger to obtain rewarmed hydrogen; the refrigerant introduced from the outside is respectively introduced into the third flow path.

[0009] In some embodiments, the test section heat exchanger measures the ortho-para hydrogen catalytic reaction rate and the para-ortho hydrogen catalytic reaction rate under specific working conditions, and the equilibrium section heat exchanger enables the hydrogen flowing through the ortho-para hydrogen catalytic conversion reaction pipeline and the para-ortho hydrogen catalytic conversion reaction pipeline to reach reaction equilibrium.

[0010] In some embodiments, ortho-para hydrogen conversion reaction catalysts are respectively arranged in the first flow path of the third-stage heat exchanger, the first flow path of the fourth-stage heat exchanger, and the first flow path of the fifth-stage heat exchanger, and the liquid hydrogen at the outlet of the first flow path of the fifth-stage heat exchanger is in an equilibrium state; Para-ortho hydrogen conversion reaction catalysts are respectively arranged in the second flow path of the fourth-stage heat exchanger, the second flow path of the third-stage heat exchanger, and the second flow path of the second-stage heat exchanger, and the hydrogen at the outlet of the second flow path of the second-stage heat exchanger is in an equilibrium state.

[0011] In some embodiments, the ortho-para hydrogen conversion reaction catalyst is different from the para-ortho hydrogen conversion reaction catalyst.

[0012] In some embodiments, the compression assembly includes an active drive gas path, and by changing the circulation flow rate through the active drive gas path while changing the pressures on both sides, the reaction kinetic parameters of the ortho-para hydrogen catalytic conversion reaction and the para-ortho hydrogen catalytic conversion reaction processes under various working conditions are obtained.

[0013] In some embodiments, the heat exchanger assembly uses a multi-stage heat exchanger for step-by-step regenerative precooling, and the para-ortho hydrogen catalytic conversion reaction fully recovers the cold energy generated during the gasification process of liquid hydrogen.

[0014] In some embodiments, the test system further includes a vacuum cold box, and the third-stage heat exchanger, the fourth-stage heat exchanger, the fifth-stage heat exchanger, and the liquid hydrogen storage tank are all arranged in the vacuum cold box.

[0015] In some embodiments, the test system further includes a pressure regulating valve, and the pressure regulating valve is arranged between the inlet of the liquid hydrogen storage tank and the fifth-stage heat exchanger; the test system further includes a gas purifier, and the gas purifier is arranged between the air inlet of the compression assembly and the heat exchanger assembly to remove impurities in the rewarmed hydrogen; The test system further includes a gas flow meter, and the gas flow meter is arranged between the air inlet of the gas purifier and the heat exchanger assembly to detect the flow rate of the rewarmed hydrogen flowing back.

[0016] In some embodiments, a rewarming mechanism is provided on each of the sampling tubes or the gas chromatograph. The rewarming mechanism is used to rewarm the sampling gas from each of the sampling tubes, and the temperature range of the gas after rewarming is between 20°C and 25°C, and the rewarming speed is between 40°C / s and 50°C / s.

[0017] The beneficial effects of the embodiments of the present application are as follows: The closed-loop system is adopted to reduce the consumption and emission of hydrogen during the test. During the test, long-term continuous measurement can be achieved, avoiding experiments due to the interruption of the gas source, and effectively improving the experimental efficiency.

[0018] By designing the circulating gas path, the compression component is used to drive the gas to circulate in the closed system. By setting multiple heat exchangers, it not only meets the test requirements for the non-equilibrium state when hydrogen leaves the test section, but also ensures that the initial conditions of hydrogen entering the test section remain balanced during continuous testing. In this test system, the test requirements for both ortho-para hydrogen and para-ortho hydrogen catalytic conversion are satisfied at the same time.

[0019] The multi-stage heat exchanger is adopted, and through step-by-step regenerative precooling, the cold energy generated during the liquefaction process is effectively recovered. This not only effectively reduces the energy consumption during the steady-state operation process, but also can greatly shorten the time required for the precooling process, further improving the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments or related technologies. Obviously, the drawings described below are only some embodiments recorded in the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is a schematic structural diagram of the ortho-para hydrogen and para-ortho hydrogen catalytic conversion test system of the present application.

[0022] Reference numerals: 1. Compressor; 2. Gas storage; 3. First-stage heat exchanger; 4. Second-stage heat exchanger; 5. First-stage refrigerant cycle; 6. Third-stage heat exchanger; 7. Second-stage refrigerant cycle; 8. Fourth-stage heat exchanger; 9. Fifth-stage heat exchanger; 10. Throttle valve; 11. Liquid hydrogen storage tank; 12. Third-stage refrigerant cycle; 13. Gas flowmeter; 14. Gas purifier; 15. Gas chromatograph; 16. Ninth branch pipeline; 17. First branch pipeline; 18. Eighth branch pipeline; 19. Seventh branch pipeline; 20. Second branch pipeline; 21. Third branch pipeline; 22. Sixth branch pipeline; 23. Fourth branch pipeline; 24. Fifth branch pipeline; 25. Vacuum cold box. Detailed implementation manners

[0023] Reference is made herein to the various solutions and features of the present application with reference to the accompanying drawings.

[0024] It should be understood that various modifications can be made to the embodiments applied herein. Therefore, the above description should not be construed as a limitation, but only as an example of the embodiments. Those skilled in the art will think of other modifications within the scope and spirit of the present application.

[0025] The accompanying drawings included in and forming a part of the specification illustrate the embodiments of the present application and, together with the general description of the present application given above and the detailed description of the embodiments given below, are used to explain the principles of the present application.

[0026] These and other features of the present application will become apparent from the following description of the preferred forms of the embodiments given by way of non-limiting examples with reference to the accompanying drawings.

[0027] It should also be understood that although the present application has been described with reference to some specific examples, those skilled in the art can surely implement many other equivalent forms of the present application.

[0028] When combined with the accompanying drawings, the above and other aspects, features and advantages of the present application will become more apparent in view of the following detailed description.

[0029] Hereinafter, specific embodiments of the present application will be described with reference to the accompanying drawings; however, it should be understood that the embodiments applied are only examples of the present application and can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details from obscuring the present application. Therefore, the specific structural and functional details applied herein are not intended to be limiting, but only as a basis and representative basis for the claims to teach those skilled in the art to use the present application in substantially any suitable detailed structure in a variety of ways.

[0030] This specification may use phrases such as "in one embodiment", "in another embodiment", "in yet another embodiment", or "in other embodiments", all of which may refer to one or more of the same or different embodiments according to the present application.

[0031] The present application provides a normal - para hydrogen and para - normal hydrogen catalytic conversion test system, which is used to test the normal - para hydrogen conversion process and the para - normal hydrogen conversion process. The test of both reaction processes can be achieved through one test system.

[0032] Combined with Figure 1 , the test system includes a compression component, a heat exchanger component, a liquid hydrogen storage tank 11, a branch pipeline component, and a gas chromatograph 15.

[0033] The compression component is used to adiabatically compress the normal - temperature hydrogen entering the compression component. The temperature of the compressed hydrogen rises, that is, the temperature of the compressed hydrogen is higher than room temperature. When compressing, the equilibrium hydrogen at normal temperature enters the compression component, and the compression component compresses the equilibrium hydrogen, so that both the temperature and pressure of the hydrogen increase. By actively driving the gas path with the compression component, the circulating flow rate can be changed while changing the pressures on both sides to obtain the kinetic characteristics of the ortho - para hydrogen catalytic reaction under more working conditions.

[0034] In some embodiments, the compression component includes a compressor 1 and a gas reservoir 2. The gas reservoir 2 is connected to the compressor 1 to receive the hydrogen heated up after being compressed by the compressor 1 and stabilize the pressure of the test system. The compressor 1 includes a compressor lubricating oil supply system, which is not shown in the figure. The hydrogen after passing through the compressor 1 is discharged into the gas reservoir 2. The function of the gas reservoir 2 is to stabilize the pressure of the test system and reduce the damage to the compressor 1 caused by the exhaust pressure fluctuation. Due to adiabatic compression, the temperature of the hydrogen entering the gas reservoir 2 is higher than the ambient temperature. Subsequently, the high - temperature hydrogen flows out of the gas reservoir 2 and enters the heat exchanger component.

[0035] The heat exchanger component includes a plurality of heat exchangers, which are connected to each other. The heat exchanger can be a spiral - wound type or a plate - fin type heat exchanger, or other types of heat exchangers. One of the heat exchangers is connected to the gas reservoir 2 in the compression component to receive the hydrogen heated up after being compressed by the compression component. Some heat exchangers are used to cool the hydrogen step by step to obtain liquid hydrogen at a set temperature. That is, the hydrogen is cooled through a plurality of heat exchangers, and the cooling temperature decreases step by step, so that after being cooled by the last heat exchanger, liquid hydrogen at the set temperature is obtained.

[0036] The refrigerant medium of the heat exchanger includes the refluxed liquid hydrogen and the externally introduced refrigerant. The temperature of the liquid hydrogen is very low. The refluxed liquid hydrogen refers to the liquid hydrogen obtained after cooling and then entering the refrigerant flow channel of the heat exchanger to cool the hydrogen to be cooled in the heat exchanger. The refluxed liquid hydrogen provides cooling capacity in different temperature ranges for the heat exchanger in the refrigerant flow channels of different heat exchangers, so as to realize the utilization of the cooling capacity of the refluxed liquid hydrogen and the cascade cooling of the hydrogen to be cooled in the heat exchanger in different temperature ranges, and then realize the ortho-para hydrogen conversion reaction under different temperature conditions, obtain hydrogen with different concentrations of ortho hydrogen and para hydrogen under different temperature conditions, sample the hydrogen during the cooling process through the branch pipeline assembly, and analyze the different concentrations of ortho hydrogen and para hydrogen in the hydrogen. The refluxed liquid hydrogen returns to the compression assembly for compression after passing through the heat exchanger, realizing the closed cycle of hydrogen.

[0037] The introduction of the external refrigerant can be realized through the refrigerant assembly. The refrigerant assembly can include a flow controller and be equipped with other components required for the refrigeration cycle, such as a refrigerant compressor, a condenser, a regulating valve, etc. (not shown in the figure). Each stage of the heat exchanger should select a suitable working medium according to the selected temperature range. Optionally, the refrigerant can be liquid nitrogen, liquid helium, liquid hydrogen, LNG, or a mixed refrigerant, etc.

[0038] Adopting a closed cycle system reduces the consumption and emission of hydrogen during the test. During the test, long-term continuous measurement can be realized, avoiding experiments due to the interruption of the gas source, and effectively improving the experimental efficiency.

[0039] The liquid hydrogen flows through some of the multiple heat exchangers to gradually heat and rewarm the liquid hydrogen in a stepped manner through the hydrogen to be cooled flowing through the heat exchanger to obtain hydrogen at a set temperature. The rewarmed hydrogen circulates back to the compression assembly to complete the closed cycle of hydrogen. That is, while the liquid hydrogen is refluxing, the liquid hydrogen can also be gradually heated and rewarmed in a stepped manner through the hydrogen to be cooled in the heat exchanger, so that the liquid hydrogen can be continuously heated by the hydrogen to be cooled at different temperatures in different heat exchangers and converted into hydrogen. During this conversion process, the para-ortho hydrogen conversion reaction occurs, realizing the utilization of the heat released by the hydrogen to be cooled, and the ortho hydrogen and para hydrogen in the hydrogen will also change at any time. Sample the refluxed liquid hydrogen under different temperature conditions to obtain hydrogen with different concentrations of ortho hydrogen and para hydrogen, and sample the hydrogen with different concentrations of ortho hydrogen and para hydrogen through the branch pipeline assembly for testing and analysis.

[0040] At least some of the multiple heat exchangers are provided with an ortho-para hydrogen conversion reaction catalyst and a para-ortho hydrogen conversion reaction catalyst to ensure that when obtaining the equilibrium state of the liquid hydrogen, the possible evaporation loss and safety risk in the future are reduced. The ortho-para hydrogen conversion reaction catalyst and the para-ortho hydrogen conversion reaction catalyst are different. For example, the ortho-para hydrogen conversion reaction catalyst can but is not limited to using nano-scale iron hydroxide.

[0041] Specifically, a para - ortho hydrogen conversion reaction catalyst is provided in the flow channel for circulating the hydrogen to be cooled in some heat exchangers. The para - ortho hydrogen conversion reaction catalyst is used to accelerate the conversion of ortho - hydrogen in hydrogen to para - hydrogen. A para - ortho hydrogen conversion reaction catalyst is provided in the flow channel for circulating the reflux liquid hydrogen in some heat exchangers. The para - ortho hydrogen conversion reaction catalyst is used to accelerate the conversion of para - hydrogen in hydrogen to ortho - hydrogen during the rewarming process of liquid hydrogen.

[0042] By designing a circulating gas path and using a compression component to drive the gas to circulate in a closed - loop system, and by providing multiple heat exchangers, it not only meets the test requirement that hydrogen reaches a non - equilibrium state when leaving the test section but also ensures that the hydrogen entering the test section always maintains an equilibrium initial condition during continuous testing. When hydrogen passes through the test - section heat exchanger, it is in a non - equilibrium state, meeting the test requirement. When passing through the equilibrium - section heat exchanger, it is in an equilibrium state. At this stage, the para - ortho hydrogen is already in an equilibrium state, without increasing the load pressure of para - ortho hydrogen catalytic conversion in subsequent links. In this test system, the test requirements for both para - ortho hydrogen and ortho - para hydrogen catalytic conversion are met. In addition, by using a multi - stage heat exchanger and through step - by - step regenerative precooling, the cold energy generated during the liquefaction process is effectively recovered. This not only effectively reduces the energy consumption during steady - state operation but also can significantly shorten the time required for the precooling process, further improving the test efficiency.

[0043] The hydrogen to be cooled is continuously cooled by a multi - stage heat exchanger and then converted into liquid hydrogen, which can be stored in the liquid hydrogen storage tank 11. Specifically, the liquid hydrogen storage tank 11 is connected to the heat exchanger that finally cools the hydrogen to the set - temperature liquid hydrogen among the multiple heat exchangers. The liquid hydrogen storage tank 11 can adopt a heat - insulated storage tank to avoid the influence of the external environmental temperature on the temperature of the liquid hydrogen in the liquid hydrogen storage tank 11 and is used to store liquid hydrogen. The liquid hydrogen in the liquid hydrogen storage tank 11 can flow back into the refrigerant flow channels of some heat exchangers through a reflux pipeline. The refrigerant flow channels for circulating liquid hydrogen in each heat exchanger can be connected through a reflux pipeline. Similarly, the flow channels for circulating the hydrogen to be cooled in each heat exchanger can be connected through a forward - flow pipeline.

[0044] The branch pipeline assembly includes multiple branch pipelines. One end of each branch pipeline is respectively connected to the hydrogen outlet of the heat exchanger, the liquid - hydrogen outlet of the heat exchanger, and the liquid hydrogen storage tank 11 to collect hydrogen or liquid hydrogen at the corresponding positions. A branch pipeline can be set at the outlet of the flow channel for circulating the hydrogen to be cooled in the heat exchanger to collect the hydrogen cooled by the heat exchanger. A branch pipeline can be set at the outlet of the flow channel for circulating the rewarming liquid hydrogen in the heat exchanger to collect the hydrogen heated and rewarmed by the heat exchanger. A branch pipeline can also be set on the liquid hydrogen storage tank 11 to collect the liquid hydrogen in the liquid hydrogen storage tank 11. The hydrogen or liquid hydrogen collected through the branch pipeline can be transported to the gas chromatograph 15 for analysis.

[0045] Among them, the sampling tube of the branch pipeline (not shown in the figure) needs to meet the rewarming requirement before entering the gas chromatograph 15. Before the gas enters the chromatograph, it should be rewarmed to room temperature or above. A pressure reducing valve is provided on the branch pipeline, and the pressure reducing valve can control the gas flow rate entering the gas chromatograph 15. The sampling tubes on each branch pipeline can rewarm the sampled gas and need to meet the temperature requirement before entering the gas chromatograph 15; the pressure reducing valves on each branch pipeline can control the gas flow rate entering the gas chromatograph 15 to meet the test requirements of the gas chromatograph 15.

[0046] Specifically, the gas chromatograph 15 is connected to the other ends of each branch pipeline to analyze the hydrogen or liquid hydrogen from each branch pipeline, and then determine the concentrations of ortho-hydrogen and para-hydrogen during the ortho-para hydrogen conversion process at different temperatures. Combining the temperature, pressure at the inlet and outlet of the flow channel, the gas flow rate in the flow channel, the filling quantity of the catalyst and other boundary conditions at this time, the reaction rate of the ortho-para hydrogen catalytic reaction under this working condition can be measured, and relevant characteristic parameters of reaction kinetics can be obtained through analysis.

[0047] In some embodiments, the heat exchanger assembly includes a first-stage heat exchanger 3, a second-stage heat exchanger 4, a third-stage heat exchanger 6, a fourth-stage heat exchanger 8 and a fifth-stage heat exchanger 9. Of course, the number of heat exchangers can be adjusted according to the actual situation, and only this is taken as an example. Among them, the third-stage heat exchanger 6 and the fourth-stage heat exchanger 8 are the test-section heat exchangers for the ortho-para hydrogen catalytic reaction and the para-ortho hydrogen catalytic reaction. The fifth-stage heat exchanger 9 is the equilibrium-section heat exchanger for the ortho-para hydrogen catalytic reaction, and the second-stage heat exchanger 4 is the equilibrium-section heat exchanger for the para-ortho hydrogen catalytic reaction.

[0048] The first-stage heat exchanger 3, the third-stage heat exchanger 6 and the fourth-stage heat exchanger 8 all include a plurality of flow channels. For example, the first-stage heat exchanger 3, the third-stage heat exchanger 6 and the fourth-stage heat exchanger 8 all include a first flow channel, a second flow channel and a third flow channel. The second-stage heat exchanger 4 includes a second flow channel and a third flow channel; the fifth-stage heat exchanger 9 includes a first flow channel and a third flow channel. The first flow channel of each heat exchanger is used for circulating the hydrogen to be cooled, the second flow channel of each heat exchanger is used for circulating the return liquid hydrogen to be rewarmed, and the third flow channel of each heat exchanger is used for circulating the refrigerant introduced from the outside.

[0049] The hydrogen compressed and heated by the compression assembly is sequentially cooled step by step through the first flow channel of the first-stage heat exchanger 3, the first flow channel of the third-stage heat exchanger 6, the first flow channel of the fourth-stage heat exchanger 8 and the first flow channel of the fifth heat exchanger to obtain liquid hydrogen, and the first flow channel of the fifth heat exchanger transports the liquid hydrogen to the liquid hydrogen storage tank 11.

[0050] The liquid hydrogen in the liquid hydrogen storage tank 11 is heated and rewarmed successively through the second flow channel of the fourth-stage heat exchanger 8, the second flow channel of the third-stage heat exchanger 6, the second flow channel of the second-stage heat exchanger 4, and the second flow channel of the first-stage heat exchanger 3 to obtain the rewarmed hydrogen. The third flow channels are respectively filled with refrigerants introduced from the outside, and the refrigerants filled in the third flow channels of different heat exchangers can be the same or different.

[0051] The test section heat exchanger is used to test the ortho-para hydrogen catalytic reaction rate and para-ortho hydrogen catalytic reaction rate under specific working conditions, and the equilibrium section heat exchanger is used to make the hydrogen flowing through the ortho-para hydrogen catalytic conversion reaction pipeline and the para-ortho hydrogen catalytic conversion reaction pipeline reach reaction equilibrium.

[0052] In some embodiments, the third flow channels of the first-stage heat exchanger 3 and the second-stage heat exchanger 4 are respectively filled with a first refrigerant, and the first refrigerant provides the cooling capacity of the first temperature zone for the first-stage heat exchanger 3 and the second-stage heat exchanger 4. The third flow channel of the third-stage heat exchanger 6 is filled with a second refrigerant, and the second refrigerant provides the cooling capacity of the second temperature zone for the third-stage heat exchanger 6. The third flow channels of the fourth-stage heat exchanger 8 and the fifth-stage heat exchanger 9 are respectively filled with a third refrigerant, and the third refrigerant provides the cooling capacity of the third temperature zone for the fourth-stage heat exchanger 8 and the fifth-stage heat exchanger 9. The temperature of the first temperature zone, the temperature of the second temperature zone, and the temperature of the third temperature zone decrease in sequence, and the temperature of the third temperature zone can be 20K - 77K. This solves the problem that the existing test device cannot carry out research on the para-ortho hydrogen catalytic reaction in the temperature range of 20 - 230 K.

[0053] Combined with the attached Figure 1 , the high-temperature hydrogen flows out from the gas reservoir 2, flows through the 3a flow channel (the first flow channel) in the first-stage heat exchanger 3, and is cooled by the hydrogen flowing back in its 3b flow channel (the second flow channel) and the refrigerant of the first-stage refrigerant circulation 5 in the 3c flow channel (the third flow channel). A first branch pipeline 17 is arranged at the outlet of the 3a flow channel; the first-stage heat exchanger 3 can adopt a three-stream plate-fin heat exchanger, and its main purpose is to remove the compression heat. The refrigerant in the first-stage refrigerant circulation 5 can adopt a mixed working medium to provide the cooling capacity in the temperature range of 230K - 300K. After passing through the first-stage heat exchanger 3, the temperature of the hydrogen decreases to between 230K and 270K.

[0054] After flowing out of the first-stage heat exchanger 3, the hydrogen will successively pass through the third-stage heat exchanger 6, the fourth-stage heat exchanger 8, and the fifth-stage heat exchanger 9, and the temperature is reduced to the liquid hydrogen temperature zone, that is, near 20K. The test system also includes a pressure regulating valve, and the pressure regulating valve is arranged between the inlet of the liquid hydrogen storage tank 11 and the fifth-stage heat exchanger 9. The pressure regulating valve can but is not limited to adopt a throttle valve 10. In the embodiment of the present application, the pressure regulating valve is taken as the throttle valve 10 as an example for illustration. The hydrogen cooled to the liquid hydrogen temperature zone by the fifth-stage heat exchanger 9 becomes liquid hydrogen after being decompressed and expanded by the throttle valve 10.

[0055] By adjusting the refrigerant flow rate, the cooling capacity entering the test system can be changed. By adjusting the frequency of the compressor 1 in the compression assembly and the opening degree of the throttle valve 10, the hydrogen flow rate in the hydrogen circulation loop and the pressures on the incoming side and the return side can be changed. After the above operations, the system operating conditions change. Wait for the system to stabilize, and then the reaction rate of the ortho-para hydrogen catalytic reaction under the new operating conditions can be measured. By repeating this process, the characteristic parameters related to the reaction kinetics of the ortho-para hydrogen catalytic reaction within a certain range can be obtained.

[0056] Positive-para hydrogen conversion reaction catalysts are respectively arranged in the first flow channels of the third-stage heat exchanger 6, the fourth-stage heat exchanger 8, and the fifth-stage heat exchanger 9. The liquid hydrogen at the outlet of the first flow channel of the fifth-stage heat exchanger 9 is in an equilibrium state. Para-positive hydrogen conversion reaction catalysts are respectively arranged in the second flow channels of the fourth-stage heat exchanger 8, the third-stage heat exchanger 6, and the second-stage heat exchanger 4. The hydrogen at the outlet of the second flow channel of the second-stage heat exchanger 4 is in an equilibrium state.

[0057] During the above cooling process, hydrogen first flows through the 6a flow channel (the first flow channel) in the third-stage heat exchanger 6 and is cooled by the hydrogen flowing back in its 6b flow channel (the second flow channel) and the refrigerant in the second-stage refrigerant cycle 7 in its 6c flow channel (the third flow channel). A second branch pipeline 20 is connected to the outlet of the 6a flow channel; among them, the 6a flow channel is filled with an appropriate amount of positive-para hydrogen conversion reaction catalyst, and during the temperature reduction process, the ortho-para hydrogen catalytic reaction occurs. The third-stage heat exchanger 6 can adopt a three-stream plate-fin heat exchanger. The main purpose of the 6a flow channel is to test the reaction kinetics characteristics of the ortho-para hydrogen catalytic reaction in a specific temperature range (77K - 230K). To achieve this purpose, an appropriate amount of catalyst should be filled in the flow channel so that the outlet hydrogen can change between the equilibrium state and the non-equilibrium state within the range of system operating condition changes. The second-stage refrigerant cycle 7 can adopt liquid nitrogen to provide the cooling capacity in the 77K - 230K temperature range.

[0058] Secondly, hydrogen first flows through the 8a flow channel (the first flow channel) in the fourth-stage heat exchanger 8 and is cooled by the hydrogen flowing back in its 8b flow channel (the second flow channel) and the refrigerant in the third-stage refrigerant cycle 12 in its 8c flow channel (the third flow channel). A third branch pipeline 21 is arranged at the outlet of the 8a flow channel; among them, the 8a flow channel is filled with an appropriate amount of positive-para hydrogen conversion reaction catalyst, and during the temperature reduction process, the ortho-para hydrogen catalytic reaction occurs. The fourth-stage heat exchanger 8 can adopt a three-stream plate-fin heat exchanger. The main purpose of the 8a flow channel is to test the reaction kinetics characteristics of the ortho-para hydrogen catalytic reaction in a specific temperature range (20K - 77K). Similar to the third-stage heat exchanger 6, an appropriate amount of catalyst should also be filled in the 8a flow channel so that the outlet hydrogen can change between the equilibrium state and the non-equilibrium state within the range of system operating condition changes. The third-stage refrigerant cycle 12 can adopt liquid hydrogen or cryogenic helium to provide the cooling capacity in the 20K - 77K temperature range.

[0059] Finally, hydrogen first flows through the 9a flow path (the first flow path) in the fifth-stage heat exchanger 9 and is cooled by the refrigerant of the third-stage refrigerant cycle 12 in its 9c flow path (the third flow path). A fourth branch pipeline 23 is provided at the outlet of the 9a flow path; among them, the 9a flow path is filled with an excessive amount of ortho-para hydrogen conversion reaction catalyst, and the ortho-para hydrogen catalytic reaction reaches equilibrium. The fifth-stage heat exchanger 9 can adopt a two-stream plate-fin heat exchanger. The main purpose of the 9a flow path is to produce equilibrium hydrogen (para hydrogen concentration above 99%) near 20K. The hydrogen at the outlet is always in an equilibrium state within the range of system operating conditions.

[0060] The purpose of the appropriate amount of catalyst is to ensure that the ortho-para hydrogen is in a non-equilibrium state at the outlet of this section of the heat exchanger for real-time testing. The purpose of filling an excessive amount of catalyst is to ensure that the ortho-para hydrogen is in an equilibrium state at the outlet of this section of the heat exchanger and ensure that the ortho-para hydrogen is fully catalytically converted at this stage.

[0061] The saturated low-temperature hydrogen in the liquid hydrogen storage tank 11 flows back, successively passes through the fourth-stage heat exchanger 8, the third-stage heat exchanger 6, and then successively passes through the second-stage heat exchanger 4 and the first-stage heat exchanger 3, and continues to be reheated to room temperature. A fifth branch pipeline 24 is connected to the liquid hydrogen storage tank 11, and a sixth branch pipeline 22 is connected to the return pipeline between the liquid hydrogen storage tank 11 and the fourth-stage heat exchanger 8.

[0062] During this process, hydrogen first flows through the 8b flow path (the second flow path) in the fourth-stage heat exchanger 8 and is heated by the incoming hydrogen in its 8a flow path (the first flow path). A seventh branch pipeline 19 is connected to the outlet of the 8b flow path. Among them, the 8b flow path is filled with an appropriate amount of para-ortho hydrogen conversion reaction catalyst, and during the heating process, the para-ortho hydrogen catalytic reaction occurs. The main purpose of the 8b flow path is to test the reaction kinetic characteristics of the para-ortho hydrogen catalytic reaction in a specific temperature range (20K - 77K). To achieve this purpose, an appropriate amount of catalyst should be filled so that the hydrogen at the outlet can reach a non-equilibrium state and an equilibrium state within the range of system operating conditions.

[0063] Secondly, hydrogen flows through the 6b flow path (the second flow path) in the third-stage heat exchanger 6 and is heated by the hydrogen flowing back in its 6a flow path (the first flow path). An eighth branch pipeline 18 is connected to the outlet of the 6b flow path. Among them, the 6b flow path is filled with an appropriate amount of para-ortho hydrogen conversion reaction catalyst, and during the heating process, the para-ortho hydrogen catalytic reaction occurs. To achieve this purpose, an appropriate amount of catalyst should be filled so that the hydrogen at the outlet can change between an equilibrium state and a non-equilibrium state within the range of system operating conditions.

[0064] When the hydrogen at the outlet is in a non-equilibrium state, the eighth branch pipeline 18, the seventh branch pipeline 19, and the sixth branch pipeline 22 are used to test the concentrations of ortho-hydrogen and para-hydrogen in the hydrogen at this time. Combining the temperature, pressure at the inlet and outlet of the flow channel, the gas flow rate in the flow channel, the filling quantity of the catalyst, and other boundary conditions at this time, the reaction rate of the ortho-para hydrogen catalytic reaction and other reaction kinetic parameters under this working condition are obtained. During the para-ortho hydrogen conversion process, a catalyst is used to accelerate the conversion rate of para-hydrogen to ortho-hydrogen, which can improve the recovery efficiency of cold energy during the conversion process.

[0065] The embodiment of the present application can obtain the reaction kinetic parameters of the entire conversion process by testing the ortho-para hydrogen catalytic conversion reaction and the para-hydrogen catalytic conversion reaction process. And the present application pays more attention to the para-hydrogen catalytic conversion reaction process to fully recover the cold energy during the conversion process.

[0066] Then the hydrogen gas flows through the 4b flow channel (the second flow channel) in the second-stage heat exchanger 4 and is heated by the refrigerant of the first-stage refrigerant cycle 5 in its 4c flow channel (the third flow channel). A ninth branch pipeline 16 is connected to the outlet of the 4b flow channel. Among them, the 4b flow channel is filled with an excessive amount of para-ortho hydrogen conversion reaction catalyst, and the para-ortho hydrogen catalytic reaction reaches equilibrium. The second-stage heat exchanger 4 can adopt a plate-fin heat exchanger with two fluid streams. The main purpose of the 4b flow channel is to produce equilibrium hydrogen (para-hydrogen concentration 75%) near 230K, and the outlet hydrogen is always in an equilibrium state within the range of system working condition changes.

[0067] Filling the para-ortho hydrogen conversion reaction catalyst in the 4b flow channel, 6b flow channel, and 8b flow channel can increase the conversion rate of para-hydrogen to ortho-hydrogen and further improve the recovery efficiency of the cold energy released during the conversion process. The para-ortho hydrogen conversion reaction catalyst can adopt nano-chromium oxide.

[0068] Finally, the hydrogen gas flows through the 3b flow channel (the second flow channel) in the first-stage heat exchanger 3 and is heated by the incoming hydrogen gas in its 3a flow channel (the first flow channel). Although the temperature continues to rise at this time, within this temperature range (230K - 300K), the para-hydrogen concentration of the equilibrium hydrogen is close to the para-hydrogen concentration of the equilibrium hydrogen at room temperature, so it is considered that the para-ortho hydrogen conversion does not occur.

[0069] The embodiments of the present application adopt cascade refrigerant cooling. The refrigerant in the first-stage refrigerant cycle 5 can use Freon refrigerant as the refrigerant to provide cooling capacity of 230K - 300K. The refrigerant in the second-stage refrigerant cycle 7 uses hydrocarbons and nitrogen as the refrigerant to provide cooling capacity of 77K - 230K. The refrigerant in the third-stage refrigerant cycle 12 uses cryogenic helium or hydrogen as the refrigerant to provide cooling capacity of 20K - 77K. The first-stage refrigerant cycle 5 in the temperature range of 230K - 300K and the second-stage refrigerant cycle 7 in the temperature range of 77K - 230K can be set as a composite cycle. The refrigerant in the temperature range of 77K - 230K can provide cooling capacity for heat media such as hydrogen in the temperature range of 230K - 300K to achieve full utilization of the cooling capacity.

[0070] After returning to room temperature, the hydrogen enters the compression assembly for circulation. The equilibrium heat exchanger (the second-stage heat exchanger 4) at the end of the rewarming process enables the reflux hydrogen about to enter the compressor 1 to fully reach the reaction equilibrium. The reaction equilibrium means that the ortho-para hydrogen conversion reaches the equilibrium concentration at this parameter point under specific parameters.

[0071] When conducting the test, first turn on the first-stage refrigerant cycle 5, the second-stage refrigerant cycle 7, and the third-stage refrigerant cycle 12, then turn on the compressor 1, and use the throttle valve 10 to control the pressures on both the incoming and reflux sides of the hydrogen. After the pressure stabilizes, adjust the circulation flow rates of the first-stage refrigerant cycle 5, the second-stage refrigerant cycle 7, and the third-stage refrigerant cycle 12, that is, adjust the cooling capacity, so that the corresponding inlet and outlet temperatures of each heat exchanger are fixed at a certain value and do not fluctuate with time. Subsequently, according to the measurement requirements, sequentially open the hydrogen sampling branch pipelines at different nodes. When sampling is required, the valves on the corresponding branch pipelines can be opened. The hydrogen in the opened sampling branch enters the gas chromatograph 15 after being rewarmed. For example, an electric tracing heating belt can be used for heating and rewarming. By analyzing with the gas chromatograph 15, the concentrations of ortho-hydrogen and para-hydrogen in the hydrogen here can be measured to study the reaction kinetic related characteristic parameters of ortho-para hydrogen catalysis and para-ortho hydrogen catalysis within a certain range.

[0072] In some embodiments, the test system further includes a vacuum cold box 25. The third-stage heat exchanger 6, the fourth-stage heat exchanger 8, the fifth-stage heat exchanger 9, and the liquid hydrogen storage tank 11 are all arranged in the vacuum cold box 25 to ensure that the outside air will not affect the temperature of the above-mentioned heat exchangers at all levels and ensure the accuracy of the test results. That is, the heat exchangers in the liquid nitrogen temperature range and below should be placed in the vacuum cold box 25, and the vacuum cold box 25 can adopt the form of multi-layer vacuum insulation.

[0073] In some embodiments, the test system further includes a temperature sensor, a pressure sensor, and a flow sensor. Temperature sensors, pressure sensors, and flow sensors are provided at the outlets of the first flow channels and the second flow channels of each heat exchanger. The hydrogen sampling circuit (the first branch pipe 17, the second branch pipe 20, the third branch pipe 21, the fourth branch pipe 23) is used to test the concentrations of ortho-hydrogen and para-hydrogen in hydrogen at this time. Combining the temperature, pressure, and gas flow rate at the inlets and outlets of the flow channels collected by each sensor at this time, as well as boundary conditions such as the filling quantity of the catalyst in each flow channel, the reaction rate of the ortho-para hydrogen catalytic reaction under this working condition can be measured. Through analysis, relevant characteristic parameters of reaction kinetics can be obtained. Among them, the gas flow rate in the flow channel can be obtained by testing with a flowmeter, and the catalyst filling quantity can be obtained by weighing before filling.

[0074] In some embodiments, the test system further includes a gas purifier 14. The gas purifier 14 is arranged between the inlet of the compression assembly and the heat exchanger assembly to remove impurities in the hydrogen after rewarming. The test system further includes a gas flowmeter 13. The gas flowmeter 13 is arranged between the inlet of the gas purifier 14 and the heat exchanger assembly to detect the flow rate of the hydrogen flowing back after rewarming.

[0075] The hydrogen rewarmed to room temperature by the first-stage heat exchanger 3 enters the gas flowmeter 13, then enters the gas purifier 14 to filter out possible impurities, and finally is sucked into the compressor 1. For example, the gas purifier 14 can be of the adsorption type, catalytic type, membrane separation type, condensation type, and chemical reaction type, etc. The specific flowmeter selection should be determined according to the range and accuracy requirements. The main consideration for the gas purifier 14 is to remove gases such as oxygen, nitrogen, carbon dioxide, and water vapor that penetrate into the system in the pipeline system, aiming to ensure that the hydrogen can remain pure during long-term operation. The lubricating oil recovery and filtration system of the compressor 1 is not shown in Figure 1 shown.

[0076] In some embodiments, a rewarming mechanism is provided on each sampling tube or the gas chromatograph 15. The rewarming mechanism is used to rewarm the sampling gases from each sampling tube. The temperature range of the rewarmed gas is between 20°C and 25°C, and the rewarming speed is between 40°C / s and 50°C / s.

[0077] The above has described multiple embodiments of the present application in detail, but the present application is not limited to these specific embodiments. Based on the concept of the present application, those skilled in the art can make various variations and modifications to the embodiments, and these variations and modifications should all fall within the scope of protection required by the present application.

Claims

1. A test system for the catalytic conversion of ortho-parahydrogen and para-ortho-hydrogen, characterized in that: include: A compression component, which is used to compress hydrogen at room temperature; A heat exchanger assembly, comprising a plurality of heat exchangers, wherein the plurality of heat exchangers are interconnected; one of the heat exchangers is connected to the compression assembly to receive the hydrogen gas that has been heated after being compressed by the compression assembly; some of the heat exchangers are used to cool the hydrogen gas step by step to obtain liquid hydrogen at a set temperature; the refrigerant medium of the heat exchanger comprises refluxed liquid hydrogen and externally introduced refrigerant; the liquid hydrogen flows through some of the plurality of heat exchangers to heat the liquid hydrogen step by step and reheat it by the hydrogen gas flowing through the heat exchanger to obtain hydrogen gas at a set temperature, and the reheated hydrogen gas circulates and flows back to the compression assembly to complete a closed cycle of the hydrogen gas; at least some of the plurality of heat exchangers are provided with a normal-para hydrogen conversion reaction catalyst and a para-normal hydrogen conversion reaction catalyst; a liquid hydrogen storage tank connected to another heat exchanger among the plurality of heat exchangers to store liquid hydrogen; A branch pipeline assembly, comprising a plurality of branch pipelines, one end of each branch pipeline being respectively connected to the hydrogen outlet of the heat exchanger, the liquid hydrogen outlet of the heat exchanger and the liquid hydrogen storage tank, so as to collect hydrogen or liquid hydrogen at corresponding positions; A gas chromatograph is connected to the other end of each branch pipeline to analyze the hydrogen gas or liquid hydrogen from each branch pipeline, so as to determine the concentration of orthohydrogen and parahydrogen in the process of orthohydrogen and parahydrogen conversion at different temperatures.

2. The ortho-parahydrogen and para-ortho-hydrogen catalytic conversion test system according to claim 1, characterized in that: The heat exchanger assembly includes a first-stage heat exchanger, a second-stage heat exchanger, a third-stage heat exchanger, a fourth-stage heat exchanger and a fifth-stage heat exchanger; wherein the third-stage heat exchanger and the fourth-stage heat exchanger are test section heat exchangers for the normal-parahydrogen catalytic reaction and the para-normal hydrogen catalytic reaction; the fifth-stage heat exchanger is an equilibrium section heat exchanger for the normal-parahydrogen catalytic reaction, and the second-stage heat exchanger is an equilibrium section heat exchanger for the para-normal hydrogen catalytic reaction; The first-stage heat exchanger, the third-stage heat exchanger and the fourth-stage heat exchanger all include a first flow channel, a second flow channel and a third flow channel; the second-stage heat exchanger includes a second flow channel and a third flow channel; the fifth-stage heat exchanger includes a first flow channel and a third flow channel; The hydrogen compressed and heated by the compression assembly is sequentially cooled step by step through the first flow channel of the first-stage heat exchanger, the first flow channel of the third-stage heat exchanger, the first flow channel of the fourth-stage heat exchanger, and the first flow channel of the fifth heat exchanger to obtain liquid hydrogen. The first flow channel of the fifth heat exchanger transports the liquid hydrogen to the liquid hydrogen storage tank. The liquid hydrogen in the liquid hydrogen storage tank is heated and restored to temperature through the second flow channel of the fourth-stage heat exchanger, the second flow channel of the third-stage heat exchanger, the second flow channel of the second-stage heat exchanger and the second flow channel of the first-stage heat exchanger in sequence to obtain restored hydrogen; the third flow channels are respectively introduced with refrigerant introduced from the outside.

3. The ortho-parahydrogen and para-ortho-hydrogen catalytic conversion test system according to claim 2, characterized in that: The test section heat exchanger is used to test the normal-para hydrogen catalytic reaction rate and the para-normal hydrogen catalytic reaction rate under specific operating conditions, and the balance section heat exchanger allows the hydrogen flowing through the normal-para hydrogen catalytic conversion reaction pipeline and the para-normal hydrogen catalytic conversion reaction pipeline to reach reaction equilibrium.

4. The ortho-parahydrogen and para-ortho-hydrogen catalytic conversion test system according to claim 3, characterized in that: A catalyst for normal-para hydrogen conversion reaction is disposed in the first flow channel of the third-stage heat exchanger, the first flow channel of the fourth-stage heat exchanger, and the first flow channel of the fifth-stage heat exchanger, respectively, and liquid hydrogen at the outlet of the first flow channel of the fifth-stage heat exchanger is in an equilibrium state; The second flow channel of the fourth-stage heat exchanger, the second flow channel of the third-stage heat exchanger and the second flow channel of the second-stage heat exchanger are respectively provided with a para-ortho-hydrogen conversion reaction catalyst, and the hydrogen at the outlet of the second flow channel of the second-stage heat exchanger is in an equilibrium state.

5. The ortho-parahydrogen and para-ortho-hydrogen catalytic conversion test system according to claim 1, characterized in that: The normal-para hydrogen conversion reaction catalyst is different from the para-ortho hydrogen conversion reaction catalyst.

6. The ortho-parahydrogen and para-ortho-hydrogen catalytic conversion test system according to claim 1, characterized in that: The compression assembly includes an active driving gas circuit, which changes the circulation flow rate while changing the pressure on both sides to obtain reaction kinetic parameters of the ortho-parahydrogen catalytic conversion reaction and para-ortho-hydrogen catalytic conversion reaction process under various working conditions.

7. The ortho-parahydrogen and para-ortho-hydrogen catalytic conversion test system according to claim 2, characterized in that: The heat exchanger assembly adopts a multi-stage heat exchanger for stage-by-stage heat recovery and pre-cooling, and the para-ortho-hydrogen catalytic conversion reaction fully recovers the cold energy generated in the process of liquid hydrogen gasification.

8. The ortho-parahydrogen and para-ortho-hydrogen catalytic conversion test system according to claim 3, characterized in that: The test system also includes a vacuum cold box, and the third-stage heat exchanger, the fourth-stage heat exchanger, the fifth-stage heat exchanger and the liquid hydrogen storage tank are all arranged in the vacuum cold box.

9. The ortho-parahydrogen and para-ortho-hydrogen catalytic conversion test system according to claim 3, characterized in that: The test system further includes a pressure regulating valve, which is arranged between the inlet of the liquid hydrogen storage tank and the fifth-stage heat exchanger; the test system further includes a gas purifier, which is arranged between the air inlet of the compression assembly and the heat exchanger assembly to remove impurities in the hydrogen after reheating; The test system further comprises a gas flow meter, which is arranged between the gas inlet of the gas purifier and the heat exchanger assembly to detect the flow rate of hydrogen gas refluxed after rewarming.

10. The ortho-parahydrogen and para-ortho-hydrogen catalytic conversion test system according to claim 1, characterized in that: Each sampling tube or the gas chromatograph is provided with a rewarming mechanism, which is used to rewarm the sampled gas from each sampling tube. The gas temperature range after rewarming is between 20°C and 25°C, and the rewarming speed is between 40°C / s and 50°C / s.

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