A high-pressure liquid hydrogen delivery system and method capable of suppressing supercritical transition

Abstract

The present invention discloses a high-pressure liquid hydrogen delivery system and method capable of suppressing supercritical transition. The system utilizes the para-orthohydrogen conversion phenomenon of liquid hydrogen itself to delay the supercritical transition phenomenon under high temperature and high pressure. The para-orthohydrogen catalytic converter is installed inside the liquid hydrogen storage tank, and the suppression of the supercritical transition is spontaneous, without the need to use additional cryogenic media or equipment. At the same time, the liquid hydrogen storage tank in the present invention can also reduce the amount of liquid hydrogen vaporized, effectively reducing the amount of liquid hydrogen loss in the preparation stage of the liquid hydrogen engine test. The overall system of the present invention is simple and the process is controllable, which can ensure that the liquid hydrogen storage tank outputs conventional liquid hydrogen, thereby improving the reliability of subsequent testing of equipment such as liquid hydrogen engines.

Description

Technical Field

[0001] The present invention relates to the field of hydrogen energy technology, and in particular to a high-pressure liquid hydrogen delivery system and method capable of suppressing supercritical transition. Background Art

[0002] Liquid hydrogen has many advantages as an engine fuel, such as zero carbon emissions, and can be widely used in aerospace, navigation and aviation vehicles. During the test of an engine fueled by liquid hydrogen, it is necessary to transport the liquid hydrogen in the ground liquid hydrogen storage tank to the engine test end in a relatively short time. In actual engineering, the liquid hydrogen in the liquid hydrogen storage tank is often input to the engine test end by pressurized delivery. In the pressurized delivery method, liquid hydrogen is pre-filled in the liquid hydrogen storage tank, and then high-pressure hydrogen is injected into the head space of the liquid hydrogen storage tank, thereby increasing the pressure in the tube and pressing the liquid hydrogen stored in the liquid hydrogen storage tank out of the outlet and into the engine test end. However, in actual applications, this approach has found that there is a large amount of supercritical hydrogen in the liquid hydrogen output from the liquid hydrogen storage tank, and the density of supercritical hydrogen is less than that of liquid hydrogen. Therefore, if supercritical hydrogen is delivered to the engine test end, the supply of hydrogen fuel will decrease, affecting normal engine testing. Therefore, it is crucial to prevent the delivery of supercritical hydrogen to it during the engine test period. However, due to the particularity and safety of liquid hydrogen experiments, no relevant technology has been found to inhibit the supercritical transition of liquid hydrogen pressurized delivery process. Summary of the invention

[0003] The purpose of the present invention is to provide a high-pressure liquid hydrogen transportation system that can suppress supercritical transition. By utilizing the secondary normal conversion endothermic phenomenon of liquid hydrogen itself, the supercritical transition speed of liquid hydrogen in the liquid hydrogen storage tank is reduced, ensuring that the liquid hydrogen storage tank can output conventional liquid hydrogen within a specified time.

[0004] The present invention intends to achieve the purpose of the present invention by the following technical scheme:

[0005] In a first aspect, the present invention provides a high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition, which comprises a pressurized hydrogen pipeline, a liquid hydrogen filling pipeline and a liquid hydrogen storage tank;

[0006] The inlet end of the pressurized hydrogen pipeline is connected to a high-pressure hydrogen source, and the outlet end is connected to the head space of the liquid hydrogen storage tank. A hydrogen valve is provided on the pressurized hydrogen pipeline;

[0007] The inlet end of the liquid hydrogen filling pipeline is connected to the bottom outlet of the liquid hydrogen storage tank, and the outlet end is connected to external equipment that needs to be supplied with liquid hydrogen. A liquid hydrogen valve is provided on the liquid hydrogen filling pipeline;

[0008] A fixing frame is installed in the liquid hydrogen storage tank, and a plurality of para-ortho-hydrogen conversion catalysts for converting para-hydrogen into ortho-hydrogen are installed on the fixing frame, and the para-ortho-hydrogen conversion catalysts are located below the initial liquid level formed after the liquid hydrogen storage tank is filled with liquid hydrogen.

[0009] As a preferred embodiment of the first aspect above, the high-pressure hydrogen source uses high-pressure hydrogen provided by a compressor or a high-pressure hydrogen cylinder group.

[0010] As a preferred embodiment of the first aspect above, each para-ortho-hydrogen conversion catalyst is in the shape of a vertically arranged long strip structure, a para-ortho-hydrogen conversion catalyst is coated on its surface, and the long strip structure as a whole extends downward from a position close to the initial liquid surface to form a para-ortho-hydrogen conversion catalytic region within a depth range below the initial liquid surface.

[0011] As a preferred embodiment of the first aspect, each secondary ortho-hydrogen conversion catalyst uses a porous medium as an attachment carrier of the secondary ortho-hydrogen conversion catalyst.

[0012] As a preferred embodiment of the first aspect, the fixing frame is a heat-conducting metal fixing frame; the fixing frame and the para-ortho-hydrogen conversion catalyst installed on the fixing frame form heat exchange contact, and the whole is located below the initial liquid level.

[0013] As a preferred embodiment of the first aspect, the para-ortho-hydrogen conversion catalysts installed on the fixing frame are evenly arranged on the inner cavity plane of the liquid hydrogen storage tank.

[0014] As a preferred embodiment of the above-mentioned first aspect, the pressurized hydrogen pipeline is provided with a hydrogen flow meter, a hydrogen temperature sensor and a hydrogen pressure sensor.

[0015] As a preferred embodiment of the above-mentioned first aspect, a liquid hydrogen flowmeter, a liquid hydrogen pressure sensor and a liquid hydrogen temperature sensor are provided on the liquid hydrogen filling pipeline.

[0016] As a preference of the above first aspect, the external device requiring liquid hydrogen supply is a liquid hydrogen engine.

[0017] In a second aspect, the present invention provides a method for delivering high-pressure liquid hydrogen required for testing a liquid hydrogen engine using the system described in any one of the schemes of the first aspect, which is specifically as follows:

[0018] First, liquid hydrogen is added into the liquid hydrogen storage tank and the initial liquid level after the filling is ensured to submerge the top of each secondary orthohydrogen conversion catalyst installed on the fixing frame, and the inner cavity of the liquid hydrogen storage tank is divided into a liquid phase area of ​​the liquid hydrogen storage tank and a gas phase area of ​​the liquid hydrogen storage tank by the liquid hydrogen level;

[0019] Then, the hydrogen valve is opened, and the hydrogen in the high-pressure hydrogen source is injected into the liquid hydrogen storage tank through the pressurized hydrogen pipeline to increase the pressure of the gas phase area of ​​the liquid hydrogen storage tank; the liquid hydrogen valve is opened and the valve opening is adjusted so that the liquid hydrogen at the bottom of the liquid phase area 8 of the liquid hydrogen storage tank is injected into the liquid hydrogen engine through the liquid hydrogen filling pipeline at the target flow rate under the pressure of the gas phase area of ​​the liquid hydrogen storage tank;

[0020] In the process of the liquid hydrogen level in the liquid hydrogen storage tank dropping, the liquid hydrogen near the two-phase interface in the liquid phase area of ​​the liquid hydrogen storage tank absorbs the heat of the pressurized hydrogen injected in the pressurized hydrogen pipeline and then heats up. This part of the heated liquid hydrogen undergoes endothermic para-ortho-conversion under the catalytic action of the para-ortho-hydrogen conversion catalyst and cools down. The supercritical transition of liquid hydrogen is suppressed by suppressing the heating rate of liquid hydrogen at the two-phase interface, thereby ensuring the normal testing of the subsequent liquid hydrogen engine.

[0021] Compared with the prior art, the present invention has the following outstanding and beneficial technical effects: utilizing the para-ortho-hydrogen conversion phenomenon of liquid hydrogen itself to delay the supercritical transition phenomenon under high temperature and high pressure, the overall system is simple and the process is controllable; the para-ortho-hydrogen catalytic converter is installed inside the liquid hydrogen storage tank, and the suppression of the supercritical transition is spontaneous, without the need to use additional cryogenic media or equipment; at the same time, the liquid hydrogen storage tank in the present invention can also reduce the vaporization amount of liquid hydrogen, effectively reducing the amount of liquid hydrogen loss in the preparation stage of liquid hydrogen engine testing.

[0022] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition according to the present invention.

[0024] In the figure: pressurized hydrogen pipeline 1, high-pressure hydrogen source 2, hydrogen valve 3, hydrogen flowmeter 4, hydrogen temperature sensor 5, hydrogen pressure sensor 6, liquid hydrogen storage tank 7, liquid phase area of ​​liquid hydrogen storage tank 8, gas phase area of ​​liquid hydrogen storage tank 9, fixing frame 10, para-orthohydrogen conversion catalyst 11, liquid hydrogen filling pipeline 12, liquid hydrogen flowmeter 13, liquid hydrogen pressure sensor 14, liquid hydrogen temperature sensor 15, liquid hydrogen valve 16. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation mode of the present invention is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0026] In the description of the present invention, it is to be understood that when an element is considered to be "connected" to another element, it may be directly connected to the other element or indirectly connected, that is, there are intermediate elements. On the contrary, when an element is said to be "directly" connected to another element, there are no intermediate elements.

[0027] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for the purpose of distinguishing descriptions, and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0028] like Figure 1 As shown, in a preferred embodiment of the present invention, a high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition is provided, and its components include a pressurized hydrogen pipeline 1, a high-pressure hydrogen source 2, a hydrogen valve 3, a hydrogen flowmeter 4, a hydrogen temperature sensor 5, a hydrogen pressure sensor 6, a liquid hydrogen storage tank 7, a liquid phase region 8 of the liquid hydrogen storage tank, a liquid phase region 9 of the liquid hydrogen storage tank, a fixing frame 10, a para-orthohydrogen conversion catalyst 11, a liquid hydrogen filling pipeline 12, a liquid hydrogen flowmeter 13, a liquid hydrogen pressure sensor 14, a liquid hydrogen temperature sensor 15 and a liquid hydrogen valve 16. The high-pressure liquid hydrogen delivery system is used to fill the liquid hydrogen in the liquid hydrogen storage tank to the test end of the liquid hydrogen engine, and the specific test end form in the liquid hydrogen engine can be selected according to the actual test needs, and is not limited to this.

[0029] The pressurized hydrogen pipeline 1 is mainly used to transport pressurized hydrogen to the liquid hydrogen storage tank. Its inlet end is connected to the high-pressure hydrogen source 2, and its outlet end is connected to the head space of the liquid hydrogen storage tank 7. The pressurized hydrogen pipeline 1 is provided with a hydrogen valve 3, a hydrogen flow meter 4, a hydrogen temperature sensor 5 and a hydrogen pressure sensor 6 in sequence from the inlet end to the outlet end. Among them, the function of the hydrogen valve 3 is to control the opening and closing of the entire pressurized hydrogen pipeline 1, the function of the hydrogen flow meter 4 is to detect the hydrogen flow in the pressurized hydrogen pipeline 1, the function of the hydrogen temperature sensor 5 is to detect the hydrogen temperature in the pressurized hydrogen pipeline 1, and the function of the hydrogen pressure sensor 6 is to detect the hydrogen pressure in the pressurized hydrogen pipeline 1.

[0030] It should be noted that the high-pressure hydrogen source 2 refers to a hydrogen source higher than normal pressure, and its specific pressure needs to be selected according to actual test needs, and is not limited to a specific pressure value. The high-pressure hydrogen source 2 can use high-pressure hydrogen provided by a compressor or a high-pressure hydrogen cylinder group. In this embodiment, a high-pressure hydrogen cylinder group is selected as the high-pressure hydrogen source 2 to provide pressurized hydrogen.

[0031] The liquid hydrogen filling pipeline 12 mainly transports the liquid hydrogen in the liquid hydrogen storage tank 7 to the liquid hydrogen engine to be tested. Its inlet end is connected to the bottom outlet of the liquid hydrogen storage tank 7, and its outlet end is connected to the external liquid hydrogen engine that needs to be supplied with liquid hydrogen. The liquid hydrogen filling pipeline 12 is provided with a liquid hydrogen flowmeter 13, a liquid hydrogen pressure sensor 14, a liquid hydrogen temperature sensor 15 and a liquid hydrogen valve 16 in sequence from the inlet end to the outlet end. Among them, the function of the liquid hydrogen valve 16 is to control the opening and closing of the entire liquid hydrogen filling pipeline 12, the function of the liquid hydrogen temperature sensor 15 is to detect the hydrogen temperature in the liquid hydrogen filling pipeline 12, the function of the liquid hydrogen pressure sensor 14 is to detect the hydrogen pressure in the liquid hydrogen filling pipeline 12, and the function of the liquid hydrogen flowmeter 13 is to detect the hydrogen flow in the liquid hydrogen filling pipeline 12.

[0032] The liquid hydrogen storage tank 7 is a closed tank body wrapped with an insulating material on the outside, and a liquid hydrogen filling port is arranged on the tube body. The inner cavity of the liquid hydrogen storage tank 7 is used to store liquid hydrogen to be filled into the liquid hydrogen engine. In practical applications, the inner cavity of the liquid hydrogen storage tank 7 is divided into a liquid hydrogen storage tank liquid phase area 8 and a liquid hydrogen storage tank gas phase area 9 by the liquid hydrogen liquid surface. When the liquid hydrogen filling pipeline 12 injects pressurized hydrogen into the liquid hydrogen storage tank gas phase area 9, the pressure of the liquid hydrogen storage tank gas phase area 9 will gradually increase, and then the liquid hydrogen in the liquid hydrogen storage tank liquid phase area 8 will be injected into the liquid hydrogen engine test end through the liquid hydrogen filling pipeline 12. This process can be called a liquid hydrogen pressurized transportation process.

[0033] Through the study of the liquid hydrogen pressurized delivery process, it is found that the main reason for the transformation of liquid hydrogen into supercritical hydrogen in the process is the temperature rise at the gas-liquid interface of the liquid phase region 8 and the gas phase region 9 of the liquid hydrogen storage tank. Since the triple point temperature and pressure of liquid hydrogen are 33.145K and 1.296MPa respectively, and the power of liquid hydrogen delivery is usually room temperature hydrogen with a pressure of up to more than ten megapascals provided by the high-pressure hydrogen source 2. Therefore, when the pressurized hydrogen enters the liquid hydrogen storage tank 7 for pressurization, in addition to the liquid hydrogen storage tank normally delivering liquid hydrogen to the engine test end, there is a temperature difference between the gas phase and the liquid phase at the gas-liquid interface, and the liquid hydrogen in contact with the pressurized hydrogen in the liquid hydrogen storage tank 7 will gradually transform into supercritical hydrogen. Since there is no latent heat of phase change when liquid hydrogen transforms into supercritical hydrogen, and the thermal conductivity of supercritical hydrogen is greater than that of liquid hydrogen, the heat of the pressurized hydrogen will be quickly transmitted to the lower part of the liquid hydrogen storage tank, so that more liquid hydrogen is transformed into supercritical hydrogen. Therefore, controlling the temperature rise of liquid hydrogen at the gas-liquid interface is the key to inhibiting the transformation of liquid hydrogen to supercritical hydrogen during the process of liquid hydrogen pressurization and transportation.

[0034] Compared with other cryogenic fluids, hydrogen is special because it exists in two states: orthohydrogen and parahydrogen. At room temperature, equilibrium hydrogen is a mixture of 75% orthohydrogen and 25% parahydrogen, called standard hydrogen. The ratio of orthohydrogen to parahydrogen in equilibrium is directly related to temperature. When the temperature is lower than room temperature and continues to decrease, the proportion of parahydrogen will increase. Therefore, when the liquid hydrogen near the gas phase of the liquid hydrogen storage tank absorbs the heat of the pressurized hydrogen and heats up, the proportion of parahydrogen corresponding to the current temperature decreases, so the orthohydrogen in the liquid hydrogen will be converted to parahydrogen. In the presence of a catalyst, the parahydrogen in the liquid hydrogen will be converted into orthohydrogen through para-ortho conversion. This para-ortho conversion is an endothermic reaction, and cold will be generated during the reaction. At the same time, since the parahydrogen content in conventional liquid hydrogen is often greater than 99%, the heat released during the conversion of liquid normal hydrogen exceeds the latent heat of vaporization of 447kJ / kg, so the cold generated by the endothermic heat of the para-ortho conversion can be used to suppress the supercritical transition rate of liquid hydrogen at the interface between the gas and liquid phases.

[0035] Based on the above principle, in this embodiment, a fixing frame 10 is installed in the liquid hydrogen storage tank 7, and a plurality of para-ortho-hydrogen conversion catalysts 11 for converting para-hydrogen into ortho-hydrogen are installed on the fixing frame 10, and the para-ortho-hydrogen conversion catalysts 11 are located below the initial liquid level formed after the liquid hydrogen storage tank 7 is filled with liquid hydrogen.

[0036] It should be noted that the initial liquid level in the liquid hydrogen storage tank 7 is adjusted according to the actual test liquid hydrogen usage and the tank body cavity volume, and does not limit the specific liquid level. Each liquid hydrogen storage tank 7 can determine the initial liquid level of its liquid hydrogen filling according to the actual test requirements, and the fixing frame 10 and the para-orthohydrogen conversion catalyst 11 can determine the installation height according to the determined initial liquid level to ensure that the para-orthohydrogen conversion catalyst 11 is located in the liquid phase area 8 of the liquid hydrogen storage tank as a whole. In the subsequent test process, the liquid hydrogen can be filled to the predetermined initial liquid level.

[0037] In addition, since the liquid hydrogen level in the liquid hydrogen storage tank 7 is not fixed, as the pressurized transportation proceeds, the liquid hydrogen level will continue to decline, the gas phase area 9 of the liquid hydrogen storage tank will continue to increase, and the liquid phase area 8 of the liquid hydrogen storage tank will continue to decrease. Therefore, in order to ensure that the liquid hydrogen below the liquid level can be suppressed by the secondary normal conversion during the liquid level decline, the secondary normal hydrogen conversion catalyst 11 can be designed to have a certain geometric height in the vertical direction of the liquid surface to increase the contact time between the liquid hydrogen and the catalyst. As a preferred implementation of the embodiment of the present invention, the shape of each secondary normal hydrogen conversion catalyst 11 installed on the fixed frame 10 is a vertically arranged long strip structure, and its surface is coated with a secondary normal hydrogen conversion catalyst. The secondary normal hydrogen conversion catalyst 11 of the long strip structure is arranged vertically in the long side direction, and its top should be located below the liquid surface but close to the liquid surface, so that the whole extends downward from a position close to the initial liquid surface, and a secondary normal hydrogen conversion catalytic area is formed within a depth range below the initial liquid surface. When the liquid hydrogen in the liquid hydrogen storage tank 7 begins to descend from the initial liquid level, since the para-ortho-hydrogen conversion catalyst 11 is arranged at a certain depth below the liquid level, the liquid hydrogen that has been heated by absorbing the heat of the hydrogen in the gas phase zone 9 of the liquid hydrogen storage tank can always contact the para-ortho-hydrogen conversion catalyst 11, thereby suppressing the supercritical transition of the liquid hydrogen at the interface between the gas and liquid phases through the para-ortho-conversion.

[0038] However, it should be noted that, in theory, the vertical arrangement depth of the para-orthohydrogen conversion catalyst 11 can extend from the initial liquid surface to the bottom of the inner cavity of the liquid hydrogen storage tank 7, thereby ensuring the liquid hydrogen supercritical transformation suppression effect during the entire liquid hydrogen pressurization and transportation process. However, in practical applications, considering the overall manufacturing cost and the supercritical transformation of liquid hydrogen caused by the actual temperature difference in the tank body cavity, it is not necessary to arrange the para-orthohydrogen conversion catalyst 11 within the entire vertical depth range, but only within a certain depth range below the initial liquid surface. As a preferred embodiment of the present invention, the arrangement depth range of the para-orthohydrogen conversion catalyst 11 with a long strip structure is: the top of the long strip structure is 1 to 10 cm below the initial liquid surface, and the bottom of the long strip structure is located at a height of 1 / 2 to 1 / 3 of the inner cavity of the liquid hydrogen storage tank 7.

[0039] It should be noted that the specific forms of the attached carrier and catalyst of the above-mentioned para-orthohydrogen conversion catalyst 11 are not limited, as long as they can catalyze the para-orthohydrogen conversion. As a preferred embodiment of the present invention, each para-orthohydrogen conversion catalyst 11 uses a three-dimensional structure with a large specific surface area such as a porous medium as an attached carrier of the para-orthohydrogen conversion catalyst, and the surface of the medium is coated with a para-orthohydrogen conversion catalyst.

[0040] In addition, as a preferred embodiment of the present invention, the fixing frame 10 preferably adopts a heat-conducting metal fixing frame, and the fixing frame 10 and the para-ortho-hydrogen conversion catalyst 11 installed on the fixing frame 10 need to form a heat exchange contact, and the fixing frame 10 and the para-ortho-hydrogen conversion catalyst 11 installed on the fixing frame 10 are located below the initial liquid level as a whole. In theory, the higher the metal thermal conductivity of the fixing frame 10, the higher the cooling capacity can be, so that the cooling capacity provided by the multiple para-ortho-hydrogen conversion catalysts 11 can be transferred to each other, maintaining the overall stability of the temperature in the area.

[0041] Furthermore, since heat transfer occurs on the entire gas-liquid interface, the ortho-parahydrogen conversion catalysts 11 installed on the fixing frame 10 should also be arranged as evenly as possible on the inner cavity plane of the liquid hydrogen storage tank 7 to avoid temperature heterogeneity within the horizontal area.

[0042] The operating principle of the above-mentioned high-pressure liquid hydrogen delivery system that can suppress supercritical transition is as follows:

[0043] The required pressurized hydrogen is supplied by the high-pressure hydrogen source 2, and the liquid hydrogen storage tank 7 is filled with an appropriate amount of liquid hydrogen in advance according to the test requirements. The hydrogen valve 3 is opened, and the room temperature and high pressure hydrogen from the high-pressure hydrogen source 2 enters the pressurized hydrogen pipeline 1, and after passing through the hydrogen valve 3, it flows through the hydrogen flowmeter 4, the hydrogen temperature sensor 5 and the hydrogen pressure sensor 6 in sequence, and then enters the liquid hydrogen storage tank 7, mixes with the low temperature hydrogen in the gas phase area 9 of the liquid hydrogen storage tank, and increases the pressure inside the liquid hydrogen storage tank 7. The liquid hydrogen valve 16 is opened, and under the action of the pressurized hydrogen, the liquid hydrogen at the bottom of the liquid phase area 8 of the liquid hydrogen storage tank enters the liquid hydrogen filling pipeline 12, flows through the liquid hydrogen flowmeter 13, the liquid hydrogen pressure sensor 14, the liquid hydrogen temperature sensor 15, the liquid hydrogen valve 16 in sequence, and is finally delivered to the liquid hydrogen engine test end. The liquid hydrogen in the liquid phase area 8 of the liquid hydrogen storage tank and the liquid hydrogen storage tank gas phase area 9 absorbs the heat of the pressurized hydrogen and starts to heat up. Since the pressure in the liquid hydrogen storage tank 7 is approximately equal to the pressure of the pressurized hydrogen, this part of the liquid hydrogen will directly transform into supercritical hydrogen when the temperature is greater than 33.145 K. Since the thermal conductivity of supercritical hydrogen is greater than that of liquid hydrogen, the supercritical transformation of liquid hydrogen will increase the heat transfer rate of the pressurized hydrogen, so it is key to slow down the temperature rise rate of the liquid hydrogen in the gas phase area 9 of the liquid hydrogen storage tank. In the liquid hydrogen storage tank 7, as the pressurized transportation proceeds, the volume of liquid hydrogen will continue to decrease, so the liquid hydrogen near the gas phase area 9 of the liquid hydrogen storage tank will contact the para-ortho-hydrogen conversion catalyst 11 located on the fixed frame 10. Since this part of the liquid hydrogen has absorbed the heat of the hydrogen in the gas phase area 9 of the liquid hydrogen storage tank, the temperature will rise, and the proportion of para-ortho-hydrogen is directly related to the temperature, so this part of the liquid hydrogen will undergo para-ortho-conversion when it contacts the para-ortho-hydrogen conversion catalyst 11, and because the para-ortho-conversion heat is greater than the vaporization heat of liquid hydrogen, the heating rate of this part of the liquid hydrogen will be greatly reduced, thereby inhibiting the supercritical transformation of liquid hydrogen in the liquid phase area 8 of the liquid hydrogen storage tank, and ultimately making the liquid hydrogen storage tank 7 output conventional liquid hydrogen, ensuring the normal test of the subsequent liquid hydrogen engine. At the same time, the liquid hydrogen storage tank in the present invention can also reduce the vaporization amount of liquid hydrogen, effectively reducing the loss of liquid hydrogen in the preparation stage of the liquid hydrogen engine test.

[0044] It should be noted that the filling flow and filling pressure finally output by the system need to be determined according to the actual test requirements. The pressure in the liquid hydrogen storage tank 7 and the liquid hydrogen pressure and flow finally output to the liquid hydrogen engine can be adjusted by adjusting the opening of the hydrogen valve 3 and the liquid hydrogen valve 16. In order to facilitate automatic adjustment, as a preferred implementation of the embodiment of the present invention, the above-mentioned hydrogen valve 3 and the liquid hydrogen valve 16 can adopt a solenoid valve that can automatically adjust the opening. The hydrogen valve 3, the hydrogen flow meter 4, the hydrogen temperature sensor 5, the hydrogen pressure sensor 6, the liquid hydrogen flow meter 13, the liquid hydrogen pressure sensor 14, the liquid hydrogen temperature sensor 15 and the liquid hydrogen valve 16 can be connected to the automatic control device, and the opening of the two valves is PID controlled according to the sensing data of each sensor, so that the final output liquid hydrogen pressure and flow meet the test requirements. Of course, this method of automatic control through solenoid valves and sensors is only a preferred implementation of the embodiment of the present invention. In actual applications, manual control can also be used, which is not limited.

[0045] Therefore, based on the above-mentioned high-pressure liquid hydrogen delivery system, the present invention can also provide a high-pressure liquid hydrogen delivery method required for liquid hydrogen engine testing, and the specific method is as follows:

[0046] First, liquid hydrogen is added into the liquid hydrogen storage tank 7 and the initial liquid level after the filling is ensured to submerge the top of each secondary orthohydrogen conversion catalyst 11 installed on the fixing frame 10. The inner cavity of the liquid hydrogen storage tank 7 is divided into a liquid hydrogen storage tank liquid phase area 8 and a liquid hydrogen storage tank gas phase area 9 by the liquid hydrogen liquid level;

[0047] Then, the hydrogen valve 3 is opened, and the hydrogen in the high-pressure hydrogen source 2 is injected into the liquid hydrogen storage tank 7 through the pressurized hydrogen pipeline 1 to increase the pressure of the gas phase area 9 of the liquid hydrogen storage tank; the liquid hydrogen valve 16 is opened and the valve opening is adjusted so that the liquid hydrogen at the bottom of the liquid phase area 8 of the liquid hydrogen storage tank is injected into the liquid hydrogen engine at a target flow rate through the liquid hydrogen filling pipeline 12 under the pressure of the gas phase area 9 of the liquid hydrogen storage tank;

[0048] In the process of the liquid hydrogen level in the liquid hydrogen storage tank 7 decreasing, the liquid hydrogen near the two-phase interface in the liquid phase region 8 of the liquid hydrogen storage tank absorbs the heat of the pressurized hydrogen injected in the pressurized hydrogen pipeline 1 and then heats up. This part of the heated liquid hydrogen undergoes endothermic secondary-normal conversion under the catalytic action of the secondary-normal hydrogen conversion catalyst 11 and cools down, thereby suppressing the supercritical transition of liquid hydrogen by suppressing the heating rate of liquid hydrogen at the two-phase interface, thereby ensuring the normal test of the subsequent liquid hydrogen engine.

[0049] Of course, it should be noted that although the system in the above embodiment of the present invention is used to transport liquid hydrogen to a liquid hydrogen engine, the system can also be used to supply liquid hydrogen to external equipment that needs to be supplied with liquid hydrogen, and is not limited to liquid hydrogen engines.

[0050] The above-described embodiment is only a preferred solution of the present invention, but it is not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition, characterized in that: It comprises a pressurized hydrogen pipeline (1), a liquid hydrogen filling pipeline (12) and a liquid hydrogen storage tank (7); The inlet end of the pressurized hydrogen pipeline (1) is connected to a high-pressure hydrogen source (2), and the outlet end is connected to the head space of a liquid hydrogen storage tank (7). A hydrogen valve (3) is provided on the pressurized hydrogen pipeline (1); The inlet end of the liquid hydrogen filling pipeline (12) is connected to the bottom outlet of the liquid hydrogen storage tank (7), and the outlet end is connected to external equipment that needs to be supplied with liquid hydrogen. The liquid hydrogen filling pipeline (12) is provided with a liquid hydrogen valve (16); A fixing frame (10) is installed in the liquid hydrogen storage tank (7), and a plurality of para-ortho-hydrogen conversion catalysts (11) for converting para-hydrogen into ortho-hydrogen are installed on the fixing frame (10), and the para-ortho-hydrogen conversion catalysts (11) are located below an initial liquid level formed after the liquid hydrogen is added to the liquid hydrogen storage tank (7); the long side direction of the para-ortho-hydrogen conversion catalysts (11) is arranged vertically, and the top of the para-ortho-hydrogen conversion catalysts (11) is located below the liquid level but close to the liquid level, so that the supercritical transition of liquid hydrogen at the gas-liquid two-phase interface is suppressed through the para-ortho-hydrogen conversion.

2. The high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition according to claim 1, characterized in that: The high-pressure hydrogen source (2) uses high-pressure hydrogen provided by a compressor or a high-pressure hydrogen cylinder group.

3. The high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition according to claim 1, characterized in that: Each of the para-ortho-hydrogen conversion catalysts (11) is in the shape of a vertically arranged long strip structure, the surface of which is coated with a para-ortho-hydrogen conversion catalyst, and the long strip structure as a whole extends downward from a position close to the initial liquid surface, forming a para-ortho-hydrogen conversion catalytic region within a depth range below the initial liquid surface.

4. The high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition according to claim 1, characterized in that: Each secondary orthohydrogen conversion catalyst (11) uses a porous medium as an attachment carrier for the secondary orthohydrogen conversion catalyst.

5. The high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition according to claim 1, characterized in that: The fixing frame (10) is a heat-conducting metal fixing frame; the fixing frame (10) and the secondary orthohydrogen conversion catalyst (11) installed on the fixing frame (10) form heat exchange contact, and the whole is located below the initial liquid surface.

6. The high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition according to claim 1, characterized in that: The ortho-parahydrogen conversion catalysts (11) mounted on the fixing frame (10) are evenly arranged on the inner cavity plane of the liquid hydrogen storage tank (7).

7. The high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition according to claim 1, characterized in that: The pressurized hydrogen pipeline (1) is provided with a hydrogen flow meter (4), a hydrogen temperature sensor (5) and a hydrogen pressure sensor (6).

8. The high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition according to claim 1, characterized in that: The liquid hydrogen filling pipeline (12) is provided with a liquid hydrogen flow meter (13), a liquid hydrogen pressure sensor (14) and a liquid hydrogen temperature sensor (15).

9. The high-pressure liquid hydrogen delivery system capable of suppressing supercritical transition according to claim 1, characterized in that: The device that needs to be supplied with liquid hydrogen externally is a liquid hydrogen engine.

10. A method for delivering high-pressure liquid hydrogen required for testing a liquid hydrogen engine using the system as claimed in any one of claims 1 to 9, characterized in that: First, liquid hydrogen is added to the liquid hydrogen storage tank (7) and the initial liquid level after the filling is ensured to submerge the top of each secondary orthohydrogen conversion catalyst (11) installed on the fixing frame (10), and the inner cavity of the liquid hydrogen storage tank (7) is divided into a liquid hydrogen storage tank liquid phase area (8) and a liquid hydrogen storage tank gas phase area (9) by the liquid hydrogen level; Then, the hydrogen valve (3) is opened, and the hydrogen in the high-pressure hydrogen source (2) is injected into the liquid hydrogen storage tank (7) through the pressurized hydrogen pipeline (1) to increase the pressure of the gas phase region (9) of the liquid hydrogen storage tank; the liquid hydrogen valve (16) is opened and the valve opening is adjusted so that the liquid hydrogen at the bottom of the liquid phase region (8) of the liquid hydrogen storage tank is injected into the liquid hydrogen engine at a target flow rate through the liquid hydrogen filling pipeline (12) under the pressure of the gas phase region (9) of the liquid hydrogen storage tank; In addition, during the process of the liquid hydrogen level in the liquid hydrogen storage tank (7) decreasing, the liquid hydrogen near the interface between the two phases in the liquid phase region (8) of the liquid hydrogen storage tank absorbs the heat of the pressurized hydrogen injected into the pressurized hydrogen pipeline (1) and then increases in temperature. This part of the heated liquid hydrogen undergoes endothermic secondary-normal conversion under the catalytic action of the secondary-normal hydrogen conversion catalyst (11) and decreases in temperature, thereby suppressing the supercritical transformation of the liquid hydrogen by suppressing the temperature increase rate of the liquid hydrogen at the interface between the two phases, thereby ensuring the normal test of the subsequent liquid hydrogen engine.

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