A pressure swing liquid hydrogen storage and supply system and method

Abstract

This invention discloses a pressure-switching liquid hydrogen storage and supply system and method, relating to the field of hydrogen-air fuel cell technology. The system includes a liquid hydrogen storage tank, a temperature controller, and a fuel cell. This invention sets different pressures in the liquid hydrogen storage tank to achieve multiple beneficial modes. By increasing the internal pressure of the liquid hydrogen storage tank, the liquid hydrogen is forced into a subcooled state, absorbing more external heat and reducing liquid hydrogen evaporation losses. By depressurizing the high-pressure liquid hydrogen, it is rapidly transformed into a lower-temperature cryogenic gas-liquid mixture, and multiple layers of cooling shields at different temperatures are strategically placed to reduce radiative heat transfer between the inner and outer tanks, improving the insulation performance of the liquid hydrogen storage tank. The generated hydrogen can supply the low-power operation mode of the fuel cell. By reducing the internal pressure of the liquid hydrogen storage tank, the high-pressure liquid hydrogen is forced into a superheated state, rapidly generating a large amount of evaporated hydrogen, which is used to supplement the fuel cell when hydrogen consumption increases sharply, significantly improving the system's hydrogen supply response capability.

Description

Technical Field

[0001] This invention relates to the field of hydrogen-air fuel cell technology, and specifically to a pressure-switched liquid hydrogen storage and supply system and method. Background Technology

[0002] Low-carbon development in aviation is a crucial direction for low-carbon development in the transportation sector, and hydrogen-powered aircraft have become one of the main development directions. For example, a new generation of hydrogen-powered aircraft is expected to enter service in the 2030s, making aviation one of the most important future applications of liquid hydrogen, and significantly impacting all aspects of the aviation supply chain. The emergence of hydrogen-powered aircraft fueled by liquid hydrogen represents a major breakthrough in the field of zero-emission aviation. Using high-energy-density liquid hydrogen as fuel, these aircraft have higher combustion efficiency and fewer emissions, bringing hope for future air transport. During flight, hydrogen-powered aircraft engage in various flight scenarios, including taxiing, takeoff, climb, cruise, descent, approach, and landing, and the demand for hydrogen fuel in fuel cells varies accordingly. As a key component connecting the liquid hydrogen fuel tank and the fuel cell, the hydrogen fuel storage and supply device needs to be dynamically adjusted in real time according to changes in the flow rate demand of the fuel cell stack, enabling it to rapidly deliver hydrogen fuel and control parameters such as temperature, pressure, and flow rate under various complex operating conditions. However, since liquid hydrogen storage and supply technology in the aviation field is still in its infancy, there is currently no mature high-precision control technology or method for hydrogen fuel state, which to some extent limits the rapid promotion and breakthrough of liquid hydrogen technology in the aviation field. Summary of the Invention

[0003] The purpose of this invention is to overcome the deficiencies in the prior art and provide a pressure-switching liquid hydrogen storage and supply system and method. This invention increases the sensible cooling capacity of liquid hydrogen by increasing the internal pressure of the liquid hydrogen storage tank, and utilizes the state transition of high-pressure liquid hydrogen to construct three layers of cooling shields with different temperature zones. By reducing the internal pressure of the liquid hydrogen storage tank, the overall hydrogen supply of the system is rapidly increased, meeting the dynamic requirements of the fuel cell system.

[0004] The specific technical solution adopted in this invention is as follows:

[0005] In a first aspect, the present invention provides a pressure-switching liquid hydrogen storage and supply system, including a liquid hydrogen storage tank, a temperature controller, and a fuel cell; the temperature controller has a first passage, a second passage, and a third passage that can form a heat exchange contact.

[0006] The liquid hydrogen storage tank includes an inner tank and an outer tank, and the interval area between the inner tank and the outer tank is a vacuum environment; along the direction away from the inner tank, a cryogenic liquid hydrogen cold screen, a cryogenic hydrogen cold screen and a neutron conversion cold screen are sequentially installed in the interval area, and the three cold screens are located in different temperature zones.

[0007] The inner tank is equipped with an electric heater, and its top is connected to an venting pipe and a high-pressure hydrogen pipeline, while its bottom is connected to a low-pressure hydrogen pipeline and a liquid hydrogen pipeline. A hydrogen venting valve is installed on the venting pipe located outside the liquid hydrogen storage tank. The inner tank is connected in sequence to a second hydrogen valve, a first pressure reducing valve, the third passage of a temperature controller, and a pressure equalizer, all located outside the liquid hydrogen storage tank, via a high-pressure hydrogen pipeline. The inner tank is connected in sequence to a second liquid hydrogen valve, the second passage of a temperature controller, a pressure equalizer, the second pressure reducing valve, and a fuel cell, all located outside the liquid hydrogen storage tank, via a liquid hydrogen pipeline. The inner tank is connected in sequence to a first liquid hydrogen valve, a throttle, and a gas-liquid separator, all located within the interval area, via a low-pressure hydrogen pipeline. The cryogenic liquid hydrogen obtained after passing through the gas-liquid separator enters a cryogenic liquid hydrogen cooling screen through a first branch, and the resulting cryogenic hydrogen enters a cryogenic hydrogen cooling screen through a second branch. The two branches flowing out from the cryogenic liquid hydrogen cooling screen and the cryogenic hydrogen cooling screen merge and enter a positive-negative conversion cooling screen, subsequently connected in sequence to the first hydrogen valve, the third passage of a temperature controller, and a pressure equalizer, all located outside the liquid hydrogen storage tank.

[0008] A circulation medium pipeline is provided between the temperature controller and the fuel cell. The circulation medium pipeline is sequentially connected to the cooling channel of the fuel cell, the circulation medium valve, the circulation pump, the first channel of the temperature controller, and the cooling channel of the fuel cell to form a circulation loop.

[0009] Preferably, the throttle body is heat-insulated externally.

[0010] Preferably, the electric heater is embedded in the inner tank.

[0011] Preferably, the circulating medium pipeline is filled with ethylene glycol solution or liquid carbon dioxide as the working medium.

[0012] Preferably, the interior of the intermediate-to-hydrogen conversion cold screen is filled with particulate intermediate-to-hydrogen conversion catalyst.

[0013] Preferably, the vent pipe is connected to the outside.

[0014] Secondly, the present invention provides a control method for the pressure-swinging liquid hydrogen storage and supply system described in any of the first aspects, as follows:

[0015] All valves are closed, all equipment is stopped, the liquid hydrogen storage tank has completed liquid hydrogen filling and the internal liquid hydrogen is under high pressure;

[0016] S1: Open the first liquid hydrogen valve, the first hydrogen valve, and the second pressure reducing valve. Use the electric heater to maintain the high pressure state of the inner tank. The high-pressure liquid hydrogen enters the low-pressure hydrogen pipeline through the first liquid hydrogen valve.

[0017] S2: In the low-pressure hydrogen pipeline, high-pressure liquid hydrogen first enters the throttle for adiabatic throttling, transforming from high-pressure liquid hydrogen into a lower-temperature low-pressure gas-liquid two-phase mixture, and then flows into the gas-liquid separator for gas-liquid separation.

[0018] S3: Cryogenic liquid hydrogen flows out from the bottom of the gas-liquid separator and enters the cryogenic liquid hydrogen cooling screen through the first branch. Since its temperature is lower than that of the liquid hydrogen in the inner tank, it can effectively cool the liquid hydrogen in the inner tank and will slowly vaporize itself. Meanwhile, cryogenic hydrogen flows out from the top of the gas-liquid separator and enters the cryogenic hydrogen cooling screen through the second branch.

[0019] S4: Hydrogen flowing out from the low-temperature hydrogen cooling screen mixes with liquid hydrogen from the low-temperature liquid hydrogen cooling screen to form new low-temperature hydrogen, which then enters the intermediate-positive conversion cooling screen together. Under the action of the intermediate-positive hydrogen conversion catalyst, intermediate-positive conversion occurs and external heat is absorbed. The low-temperature liquid hydrogen cooling screen, low-temperature hydrogen cooling screen, and intermediate-positive conversion cooling screen effectively separate the ambient temperature of the interval area from the liquid hydrogen temperature, reducing the radiative heat exchange.

[0020] The system will then select one of three operating modes based on the hydrogen fuel demand of the fuel cell, as follows:

[0021] When the fuel cell has a low demand for hydrogen fuel, the system operates in a low-power mode, as follows:

[0022] S51: The hydrogen gas that has been converted in the Zhongzheng conversion cold screen enters the third channel of the temperature controller through the first hydrogen valve to absorb heat;

[0023] S61: After the hydrogen reaches the required temperature for the fuel cell in the temperature controller, it enters the equalizer and then the pressure is reduced by the second pressure reducing valve. After reaching the required pressure for the fuel cell, it enters the fuel cell and is converted into electrical energy.

[0024] When the fuel cell's hydrogen fuel demand is normal, the system operates in standard mode, as follows:

[0025] S52: Open the second liquid hydrogen valve; the liquid hydrogen in the inner tank enters the liquid hydrogen pipeline under the action of pressure difference, and first enters the second channel of the temperature controller to absorb heat, completing vaporization and heating.

[0026] S62: The hydrogen gas that has been converted in the Zhongzheng conversion cold screen enters the third channel of the temperature controller through the first hydrogen valve to absorb heat;

[0027] S72: After the two streams of hydrogen in the second and third channels of the temperature controller reach the temperature required by the fuel cell, they enter the equalizer for pressure equalization and mixing. Then, the pressure is reduced by the second pressure reducing valve. After reaching the pressure required by the fuel cell, the hydrogen enters the fuel cell and is converted into electrical energy.

[0028] When the fuel cell has a high demand for hydrogen fuel, the system operates in a high-power mode, as follows:

[0029] S53: Open the second liquid hydrogen valve; the liquid hydrogen in the inner tank enters the liquid hydrogen pipeline under the action of pressure difference, and first enters the second channel of the temperature controller to absorb heat, completing vaporization and heating.

[0030] S63: Open the second hydrogen valve and the first pressure reducing valve. The pressure in the inner tank drops rapidly. Some of the liquid hydrogen will vaporize rapidly and reach a new equilibrium state. The hydrogen produced by vaporization enters the first pressure reducing valve through the second hydrogen valve for pressure reduction. Then it mixes with the hydrogen from the first hydrogen valve and enters the third channel of the temperature controller to absorb heat.

[0031] S73: After the two streams of hydrogen in the second and third channels of the temperature controller reach the temperature required by the fuel cell, they enter the equalizer for equalization and mixing. Then, the pressure is reduced by the second pressure reducing valve. After reaching the pressure required by the fuel cell, the hydrogen enters the fuel cell and is converted into electrical energy.

[0032] During operation in the three operating modes, the circulating medium valve is opened and the circulating pump is started. The circulating medium in the circulating medium pipeline first enters the cooling channel of the fuel cell to absorb heat, and then enters the circulating pump through the circulating medium valve to be pressurized. After being pressurized, it enters the first channel of the temperature controller to release heat, and finally returns to the cooling channel of the fuel cell to absorb heat again, and the cycle repeats.

[0033] The significant and beneficial technical effects of this invention compared to existing technologies are as follows: By setting different pressures in the liquid hydrogen storage tank, multiple beneficial modes can be achieved. Increasing the internal pressure of the liquid hydrogen storage tank induces the liquid hydrogen into a supercooled state, allowing it to absorb more external heat and reducing liquid hydrogen evaporation losses. Depressurizing the high-pressure liquid hydrogen rapidly transforms it into a lower-temperature cryogenic gas-liquid mixture, and by strategically incorporating multiple layers of cooling shields at different temperatures, the radiative heat transfer between the inner and outer tanks is reduced to a limited extent, improving the thermal insulation performance of the liquid hydrogen storage tank. The generated hydrogen can then supply the low-power operation mode of the fuel cell. Furthermore, reducing the internal pressure of the liquid hydrogen storage tank induces the high-pressure liquid hydrogen into a superheated state, rapidly generating a large amount of evaporated hydrogen, which can be used to supplement the fuel cell when hydrogen consumption increases sharply, significantly improving the system's hydrogen supply response capability.

[0034] The following will further explain the concept, specific structure and technical effects of the present invention with reference to the accompanying drawings, so as to fully understand the purpose, features and effects of the present invention. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of a pressure-switching liquid hydrogen storage and supply system according to the present invention.

[0036] In the diagram: Liquid hydrogen storage tank 1, inner tank 2, outer tank 3, electric heater 4, low-pressure hydrogen pipeline 5, first liquid hydrogen valve 6, throttle valve 7, gas-liquid separator 8, cryogenic liquid hydrogen cooling screen 9, cryogenic hydrogen cooling screen 10, neutron conversion cooling screen 11, first hydrogen valve 12, hydrogen vent valve 13, high-pressure hydrogen pipeline 14, second hydrogen valve 15, first pressure reducing valve 16, liquid hydrogen pipeline 17, second liquid hydrogen valve 18, temperature controller 19, pressure equalizer 20, second pressure reducing valve 21, fuel cell 22, circulating medium pipeline 23, circulating medium valve 24, circulating pump 25. Detailed Implementation

[0037] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Technical features in the various embodiments of the present invention can be combined accordingly without mutual conflict.

[0038] In the description of this invention, it should be understood that when an element is considered to be "connected" to another element, it can be a direct connection to the other element or an indirect connection, i.e., there is an intermediate element. Conversely, when an element is said to be "directly" connected to another element, there is no intermediate element.

[0039] In the description of this invention, it should be understood that the terms "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features.

[0040] In the description of this invention, it should be understood that the terms "low pressure" and "high pressure" in the components "low-pressure hydrogen pipeline 5, high-pressure hydrogen pipeline 14" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the pressure limitation of the indicated technical features.

[0041] In the description of this invention, it should be understood that the expression "low temperature" in the components "low temperature liquid hydrogen cooling screen 9, low temperature hydrogen cooling screen 10" is only used for distinguishing descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the temperature limitation of the indicated technical features.

[0042] like Figure 1As shown, this invention provides a pressure-switching liquid hydrogen storage and supply system, which mainly includes a liquid hydrogen storage tank 1, an inner tank 2, an outer tank 3, an electric heater 4, a low-pressure hydrogen pipeline 5, a first liquid hydrogen valve 6, a throttle valve 7, a gas-liquid separator 8, a cryogenic liquid hydrogen cooling screen 9, a cryogenic hydrogen cooling screen 10, a neutral-to-positive conversion cooling screen 11, a first hydrogen valve 12, a hydrogen vent valve 13, a high-pressure hydrogen pipeline 14, a second hydrogen valve 15, a first pressure reducing valve 16, a liquid hydrogen pipeline 17, a second liquid hydrogen valve 18, a temperature controller 19, a pressure equalizer 20, a second pressure reducing valve 21, a fuel cell 22, a circulating medium pipeline 23, a circulating medium valve 24, and a circulating pump 25.

[0043] The temperature controller 19 has a first passage, a second passage, and a third passage that can form a heat exchange contact and are complementaryly connected.

[0044] The structure and connection method of each component of the present invention will be described in detail below.

[0045] In this invention, the liquid hydrogen storage tank 1 includes an inner tank 2 and an outer tank 3 nested within each other. The inner tank 2 is nested within the inner cavity of the outer tank 3, with a certain gap between them. The gap area between the inner tank 2 and the outer tank 3 is evacuated to create a vacuum environment, and multiple layers of cold shields and radiation shields are installed within the gap area. Specifically, along the direction gradually moving away from the inner tank 2, a cryogenic liquid hydrogen cold shield 9, a cryogenic hydrogen cold shield 10, and a positron conversion cold shield 11 are sequentially installed within the gap area, with each of the three cold shields located in a different temperature zone. That is, the cryogenic liquid hydrogen cold shield 9 is closest to the inner tank 2, and the positron conversion cold shield 11 is farthest from the inner tank 2. The cryogenic liquid hydrogen cold shield, the cryogenic hydrogen cold shield, and the positron conversion cold shield are arranged sequentially from the inside out, dividing the ambient temperature and the internal liquid hydrogen temperature into multiple temperature zones, which can effectively reduce radiative heat transfer.

[0046] In a preferred embodiment of the present invention, the interior of the neutronic conversion cooling screen 11 is filled with particulate neutronic hydrogen conversion catalyst to promote the neutronic conversion of hydrogen and further release cooling capacity. The cryogenic liquid hydrogen cooling screen 9, the cryogenic hydrogen cooling screen 10, and the neutronic conversion cooling screen 11 should all cover the inner tank 2 as much as possible.

[0047] In this invention, the inner tank 2 is equipped with an electric heater 4, which regulates the internal pressure of the liquid hydrogen storage tank 1 by heating and vaporizing liquid hydrogen. The top of the inner tank 2 is connected to an venting pipe and a high-pressure hydrogen pipeline 14, and the bottom is connected to a low-pressure hydrogen pipeline 5 and a liquid hydrogen pipeline 17. A hydrogen venting valve 13 is installed on the venting pipe located outside the liquid hydrogen storage tank 1. The venting pipe is used to vent hydrogen and prevent overpressure. The inner tank 2 is connected in sequence to a second hydrogen valve 15, a first pressure reducing valve 16, the third passage of a temperature controller 19, and a pressure equalizer 20 located outside the liquid hydrogen storage tank 1 via the high-pressure hydrogen pipeline 14. The high-pressure hydrogen pipeline 14 is used to quickly replenish hydrogen fuel for the fuel cell 22. The inner tank 2 is connected in sequence to the second liquid hydrogen valve 18, the second passage of the temperature controller 19, the equalizer 20, the second pressure reducing valve 21, and the fuel cell 22, all located outside the liquid hydrogen storage tank 1, via a liquid hydrogen pipeline 17. The liquid hydrogen pipeline 17 is used to vaporize the liquid hydrogen inside the liquid hydrogen storage tank 1 to supply the fuel cell 22 for power generation. The inner tank 2 is connected in sequence to the first liquid hydrogen valve 6, the throttle 7, and the gas-liquid separator 8, all located in the interval area, via a low-pressure hydrogen pipeline 5. The cryogenic liquid hydrogen obtained after passing through the gas-liquid separator 8 enters the cryogenic liquid hydrogen cooling screen 9 through the first branch, and the resulting cryogenic hydrogen enters the cryogenic hydrogen cooling screen 10 through the second branch. The two branches flowing out from the cryogenic liquid hydrogen cooling screen 9 and the cryogenic hydrogen cooling screen 10 merge and enter the positive conversion cooling screen 11, which is then connected in sequence to the first hydrogen valve 12, the third passage of the temperature controller 19, and the equalizer 20, all located outside the liquid hydrogen storage tank 1.

[0048] In a preferred embodiment of the present invention, the electric heater 4 can be embedded in the inner tank 2 to reduce heat loss and improve safety. The exterior of the throttle should be insulated to convert the high-pressure liquid hydrogen inside into a low-pressure gas-liquid two-phase mixture under insulated conditions, thereby reducing the overall temperature.

[0049] In this invention, a circulation medium pipeline 23 is provided between the temperature controller 19 and the fuel cell 22. Specifically, the circulation medium pipeline 23 is sequentially connected to the cooling channel of the fuel cell 22, the circulation medium valve 24, the circulation pump 25, the first channel of the temperature controller 19, and the cooling channel of the fuel cell 22 to form a circulation loop. The circulation medium pipeline 23 can utilize the heat generated by the operation of the fuel cell 22 to heat the cryogenic hydrogen and liquid hydrogen.

[0050] In a preferred embodiment of the present invention, the circulating medium pipeline 23 may be filled with ethylene glycol solution or liquid carbon dioxide as the working medium.

[0051] Utilizing the aforementioned pressure-swing liquid hydrogen storage and supply system, this invention also provides a control method (i.e., operating principle), which is as follows:

[0052] The system mainly includes three different operating modes. First, it is assumed that all valves are closed, all devices are stopped, liquid hydrogen storage tank 1 has completed liquid hydrogen filling and the internal liquid hydrogen is under high pressure.

[0053] 1. Low power operation mode: Fuel cell 22 has a low demand for hydrogen fuel.

[0054] (1) Open the first liquid hydrogen valve 6, the first hydrogen valve 12, and the second pressure reducing valve 21. Use the electric heater 4 to maintain the high pressure state of the inner tank 2. The high pressure liquid hydrogen enters the low pressure hydrogen pipeline 5 through the first liquid hydrogen valve 6.

[0055] The "high pressure state" here can be specified as a pressure threshold as needed. "High pressure liquid hydrogen" is "high pressure" relative to the liquid hydrogen pressure in the rest of the system.

[0056] (2) In the low-pressure hydrogen pipeline 5, the high-pressure liquid hydrogen first enters the throttle 7 for adiabatic throttling, and is transformed from high-pressure liquid hydrogen into a low-pressure gas-liquid two-phase mixture with a lower temperature. Then it flows into the gas-liquid separator 8 for gas-liquid separation.

[0057] The terms "high pressure" and "low pressure" here are relative pressure states.

[0058] (3) Low-temperature liquid hydrogen flows out from the bottom of the gas-liquid separator 8 and enters the low-temperature liquid hydrogen cooling screen 9 through the first branch. Since its temperature is lower than that of the liquid hydrogen in the inner tank 2, it can effectively cool the liquid hydrogen in the inner tank 2 and slowly vaporize. Low-temperature hydrogen flows out from the top of the gas-liquid separator 8 and enters the low-temperature hydrogen cooling screen 10 through the second branch.

[0059] The term "cryogenic liquid hydrogen" here refers to "cryogenic temperature" relative to the temperature of liquid hydrogen in the rest of the system.

[0060] (4) The hydrogen flowing out from the low-temperature hydrogen cooling screen 10 mixes with the liquid hydrogen from the low-temperature liquid hydrogen cooling screen 9 to form new low-temperature hydrogen and enter the intermediate-positive conversion cooling screen 11 together. Under the action of the intermediate-positive hydrogen conversion catalyst, intermediate-positive conversion occurs and external heat is absorbed. The low-temperature liquid hydrogen cooling screen 9, the low-temperature hydrogen cooling screen 10, and the intermediate-positive conversion cooling screen 11 effectively separate the ambient temperature of the interval area from the liquid hydrogen temperature, reducing the radiative heat exchange.

[0061] (5) The hydrogen gas that has been converted in the Zhongzheng conversion cooling screen 11 enters the third channel of the temperature controller 19 through the first hydrogen valve 12 to absorb heat.

[0062] (6) After the hydrogen reaches the temperature required by the fuel cell 22 in the temperature controller 19, it enters the equalizer 20 and then the pressure is reduced by the second pressure reducing valve 21. After reaching the pressure required by the fuel cell 22, it enters the fuel cell 22 and is converted into electrical energy.

[0063] (7) Open the circulating medium valve 24 and start the circulating pump 25. The circulating medium in the circulating medium pipeline 23 first enters the cooling channel of the fuel cell 22 to absorb heat, and then enters the circulating pump 25 through the circulating medium valve 24 to be pressurized. After being pressurized, it enters the first channel of the temperature controller 19 to release heat, and finally returns to the cooling channel of the fuel cell 22 to absorb heat again, and repeats the cycle.

[0064] 2. Standard operating mode: Fuel cell 22 has normal hydrogen fuel requirements.

[0065] (1) Open the first liquid hydrogen valve 6, the first hydrogen valve 12, and the second pressure reducing valve 21. Use the electric heater 4 to maintain the high pressure state of the inner tank 2. The high pressure liquid hydrogen enters the low pressure hydrogen pipeline 5 through the first liquid hydrogen valve 6.

[0066] (2) In the low-pressure hydrogen pipeline 5, the high-pressure liquid hydrogen first enters the throttle 7 for adiabatic throttling, and is transformed from high-pressure liquid hydrogen into a low-pressure gas-liquid two-phase mixture with a lower temperature. Then it flows into the gas-liquid separator 8 for gas-liquid separation.

[0067] (3) Low-temperature liquid hydrogen flows out from the bottom of the gas-liquid separator 8 and enters the low-temperature liquid hydrogen cooling screen 9 through the first branch. Since its temperature is lower than that of the liquid hydrogen in the inner tank 2, it can effectively cool the liquid hydrogen in the inner tank 2 and slowly vaporize. Low-temperature hydrogen flows out from the top of the gas-liquid separator 8 and enters the low-temperature hydrogen cooling screen 10 through the second branch.

[0068] (4) The hydrogen flowing out from the low-temperature hydrogen cooling screen 10 mixes with the liquid hydrogen from the low-temperature liquid hydrogen cooling screen 9 to form new low-temperature hydrogen and enter the intermediate-positive conversion cooling screen 11 together. Under the action of the intermediate-positive hydrogen conversion catalyst, intermediate-positive conversion occurs and external heat is absorbed. The low-temperature liquid hydrogen cooling screen 9, the low-temperature hydrogen cooling screen 10, and the intermediate-positive conversion cooling screen 11 effectively separate the ambient temperature of the interval area from the liquid hydrogen temperature, reducing the radiative heat exchange.

[0069] (5) Open the second liquid hydrogen valve 18. The liquid hydrogen in the inner tank 2 enters the liquid hydrogen pipeline 17 under the action of pressure difference. It first enters the second channel of the temperature controller 19 to absorb heat and complete vaporization and heating.

[0070] (6) The hydrogen gas that has been converted in the Zhongzheng conversion cooling screen 11 enters the third channel of the temperature controller 19 through the first hydrogen valve 12 to absorb heat.

[0071] (7) After the two streams of hydrogen in the second and third channels of the temperature controller 19 reach the required temperature of the fuel cell 22, they enter the equalizer 20 for equalization and mixing. Then, the pressure is reduced by the second pressure reducing valve 21. After reaching the required pressure of the fuel cell 22, the hydrogen enters the fuel cell 22 and is converted into electrical energy.

[0072] (8) Open the circulating medium valve 24 and start the circulating pump 25. The circulating medium in the circulating medium pipeline 23 first enters the cooling channel of the fuel cell 22 to absorb heat, and then enters the circulating pump 25 through the circulating medium valve 24 to be pressurized. After being pressurized, it enters the first channel of the temperature controller 19 to release heat, and finally returns to the cooling channel of the fuel cell 22 to absorb heat again, and repeats the cycle.

[0073] 3. High-power operation mode: Fuel cell 22 has a high demand for hydrogen fuel.

[0074] (1) Open the first liquid hydrogen valve 6, the first hydrogen valve 12, and the second pressure reducing valve 21. Use the electric heater 4 to maintain the high pressure state of the inner tank 2. The high pressure liquid hydrogen enters the low pressure hydrogen pipeline 5 through the first liquid hydrogen valve 6.

[0075] (2) In the low-pressure hydrogen pipeline 5, the high-pressure liquid hydrogen first enters the throttle 7 for adiabatic throttling, and is transformed from high-pressure liquid hydrogen into a low-pressure gas-liquid two-phase mixture with a lower temperature. Then it flows into the gas-liquid separator 8 for gas-liquid separation.

[0076] (3) Low-temperature liquid hydrogen flows out from the bottom of the gas-liquid separator 8 and enters the low-temperature liquid hydrogen cooling screen 9 through the first branch. Since its temperature is lower than that of the liquid hydrogen in the inner tank 2, it can effectively cool the liquid hydrogen in the inner tank 2 and slowly vaporize. Low-temperature hydrogen flows out from the top of the gas-liquid separator 8 and enters the low-temperature hydrogen cooling screen 10 through the second branch.

[0077] (4) The hydrogen flowing out from the low-temperature hydrogen cooling screen 10 mixes with the liquid hydrogen from the low-temperature liquid hydrogen cooling screen 9 to form new low-temperature hydrogen and enter the intermediate-positive conversion cooling screen 11 together. Under the action of the intermediate-positive hydrogen conversion catalyst, intermediate-positive conversion occurs and external heat is absorbed. The low-temperature liquid hydrogen cooling screen 9, the low-temperature hydrogen cooling screen 10, and the intermediate-positive conversion cooling screen 11 effectively separate the ambient temperature of the interval area from the liquid hydrogen temperature, reducing the radiative heat exchange.

[0078] (5) Open the second liquid hydrogen valve 18. The liquid hydrogen in the inner tank 2 enters the liquid hydrogen pipeline 17 under the action of pressure difference. It first enters the second channel of the temperature controller 19 to absorb heat and complete vaporization and heating.

[0079] (6) Open the second hydrogen valve 15 and the first pressure reducing valve 16. The pressure in the inner tank 2 drops rapidly, and some liquid hydrogen will quickly vaporize to reach a new equilibrium state. The hydrogen produced by vaporization enters the first pressure reducing valve 16 through the second hydrogen valve 15 for pressure reduction, and then flows into the low-pressure hydrogen pipeline 5, mixes with the hydrogen from the first hydrogen valve 12, and enters the third channel of the temperature controller 19 together to absorb heat.

[0080] (7) After the two streams of hydrogen in the second and third channels of the temperature controller 19 reach the required temperature of the fuel cell 22, they enter the equalizer 20 for equalization and mixing. Then, the pressure is reduced by the second pressure reducing valve 21. After reaching the required pressure of the fuel cell 22, the hydrogen enters the fuel cell 22 and is converted into electrical energy.

[0081] (8) Open the circulating medium valve 24 and start the circulating pump 25. The circulating medium in the circulating medium pipeline 23 first enters the cooling channel of the fuel cell 22 to absorb heat, and then enters the circulating pump 25 through the circulating medium valve 24 to be pressurized. After being pressurized, it enters the first channel of the temperature controller 19 to release heat, and finally returns to the cooling channel of the fuel cell 22 to absorb heat again, and repeats the cycle.

[0082] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A pressure-swinging liquid hydrogen storage and supply system, characterized in that, It includes a liquid hydrogen storage tank (1), a temperature controller (19), and a fuel cell (22); the temperature controller (19) has a first passage, a second passage, and a third passage that can form a heat exchange contact. The liquid hydrogen storage tank (1) includes an inner tank (2) and an outer tank (3) fitted together. The space between the inner tank (2) and the outer tank (3) is a vacuum environment. Along the direction away from the inner tank (2), a cryogenic liquid hydrogen cooling screen (9), a cryogenic hydrogen cooling screen (10) and a neutron conversion cooling screen (11) are arranged in sequence in the space. The three cooling screens are located in different temperature zones. The inner tank (2) is equipped with an electric heater (4), and its top is connected to an venting pipe and a high-pressure hydrogen pipeline (14), respectively. Its bottom is connected to a low-pressure hydrogen pipeline (5) and a liquid hydrogen pipeline (17), respectively. A hydrogen venting valve (13) is provided on the venting pipe located outside the liquid hydrogen storage tank (1). The inner tank (2) is connected in sequence to the second hydrogen valve (15), the first pressure reducing valve (16), the third passage of the temperature controller (19), and the equalizer (20) located outside the liquid hydrogen storage tank (1) via the high-pressure hydrogen pipeline (14). The inner tank (2) is connected in sequence to the second liquid hydrogen valve (18), the second passage of the temperature controller (19), and the equalizer (20) located outside the liquid hydrogen storage tank (1) via the liquid hydrogen pipeline (17). The inner tank (2) is connected to the second pressure reducing valve (21) and the fuel cell (22) in sequence through the low-pressure hydrogen pipeline (5) to the first liquid hydrogen valve (6), the throttle (7), and the gas-liquid separator (8) located in the interval area; the cryogenic liquid hydrogen obtained after passing through the gas-liquid separator (8) enters the cryogenic liquid hydrogen cooling screen (9) through the first branch, and the obtained cryogenic hydrogen enters the cryogenic hydrogen cooling screen (10) through the second branch. The two branches flowing out from the cryogenic liquid hydrogen cooling screen (9) and the cryogenic hydrogen cooling screen (10) merge and enter the positive conversion cooling screen (11), and then are connected in sequence to the first hydrogen valve (12), the third passage of the temperature controller (19), and the equalizer (20) located outside the liquid hydrogen storage tank (1); A circulation medium pipeline (23) is provided between the temperature controller (19) and the fuel cell (22). The circulation medium pipeline (23) is connected in sequence to the cooling channel of the fuel cell (22), the circulation medium valve (24), the circulation pump (25), the first channel of the temperature controller (19), and the cooling channel of the fuel cell (22) to form a circulation loop.

2. The pressure-switching liquid hydrogen storage and supply system according to claim 1, characterized in that, The throttle (7) is externally insulated.

3. The pressure-switching liquid hydrogen storage and supply system according to claim 1, characterized in that, The electric heater (4) is embedded in the inner tank (2).

4. The pressure-switching liquid hydrogen storage and supply system according to claim 1, characterized in that, The circulating medium pipeline (23) is filled with ethylene glycol solution or liquid carbon dioxide as the working medium.

5. A pressure-switching liquid hydrogen storage and supply system according to claim 1, characterized in that, The interior of the intermediate-to-hydrogen conversion cold screen (11) is filled with particulate intermediate-to-hydrogen conversion catalyst.

6. The pressure-switching liquid hydrogen storage and supply system according to claim 1, characterized in that, The drainage pipe is connected to the outside.

7. A control method for the pressure-swinging liquid hydrogen storage and supply system according to any one of claims 1 to 6, characterized in that, Specifically as follows: All valves are closed, all devices are stopped, and the liquid hydrogen storage tank (1) has completed liquid hydrogen filling and the liquid hydrogen inside is under high pressure. S1: Open the first liquid hydrogen valve (6), the first hydrogen valve (12), and the second pressure reducing valve (21). Use the electric heater (4) to maintain the high pressure state of the inner tank (2). The high pressure liquid hydrogen enters the low pressure hydrogen pipeline (5) through the first liquid hydrogen valve (6). S2: In the low-pressure hydrogen pipeline (5), the high-pressure liquid hydrogen first enters the throttle (7) for adiabatic throttling, and is transformed from high-pressure liquid hydrogen into a low-pressure gas-liquid two-phase mixture with a lower temperature. Then it flows into the gas-liquid separator (8) for gas-liquid separation. S3: Low-temperature liquid hydrogen flows out from the bottom of the gas-liquid separator (8) and enters the low-temperature liquid hydrogen cooling screen (9) through the first branch. Since its temperature is lower than that of the liquid hydrogen in the inner tank (2), it can effectively cool the liquid hydrogen in the inner tank (2) and will slowly vaporize itself. Low-temperature hydrogen flows out from the top of the gas-liquid separator (8) and enters the low-temperature hydrogen cooling screen (10) through the second branch. S4: Hydrogen flowing out from the low-temperature hydrogen cooling screen (10) mixes with liquid hydrogen from the low-temperature liquid hydrogen cooling screen (9) to form new low-temperature hydrogen and enter the intermediate-positive conversion cooling screen (11). Under the action of the intermediate-positive hydrogen conversion catalyst, intermediate-positive conversion occurs and external heat is absorbed. The low-temperature liquid hydrogen cooling screen (9), the low-temperature hydrogen cooling screen (10), and the intermediate-positive conversion cooling screen (11) effectively separate the ambient temperature of the interval area from the liquid hydrogen temperature, reducing the radiative heat exchange. The system will then select one of three operating modes based on the hydrogen fuel demand of the fuel cell (22), as follows: When the fuel cell (22) has a low demand for hydrogen fuel, the system operates in a low-power mode, as follows: S51: The hydrogen gas that has been converted in the Zhongzheng conversion cold screen (11) enters the third channel of the temperature controller (19) through the first hydrogen valve (12) to absorb heat; S61: After the hydrogen reaches the temperature required by the fuel cell (22) in the temperature controller (19), it enters the equalizer (20), and then the pressure is reduced by the second pressure reducing valve (21) until it reaches the pressure required by the fuel cell (22) and enters the fuel cell (22) to be converted into electrical energy. When the fuel cell (22) has a normal hydrogen fuel requirement, the system is in standard operating mode, as follows: S52: Open the second liquid hydrogen valve (18); the liquid hydrogen in the inner tank (2) enters the liquid hydrogen pipeline (17) under the action of pressure difference, and first enters the second channel of the temperature controller (19) to absorb heat, and completes vaporization and heating; S62: The hydrogen gas that has been converted in the Zhongzheng conversion cold screen (11) enters the third channel of the temperature controller (19) through the first hydrogen valve (12) to absorb heat; S72: After the two streams of hydrogen in the second and third channels of the temperature controller (19) reach the temperature required by the fuel cell (22), they enter the equalizer (20) for equalization and mixing. Then, they are depressurized by the second pressure reducing valve (21) and enter the fuel cell (22) to be converted into electrical energy after reaching the pressure required by the fuel cell (22). When the fuel cell (22) has a high demand for hydrogen fuel, the system operates in a high-power mode, as follows: S53: Open the second liquid hydrogen valve (18); the liquid hydrogen in the inner tank (2) enters the liquid hydrogen pipeline (17) under the action of pressure difference, and first enters the second channel of the temperature controller (19) to absorb heat, and completes vaporization and heating; S63: Open the second hydrogen valve (15) and the first pressure reducing valve (16). The pressure in the inner tank (2) drops rapidly. Some liquid hydrogen will vaporize rapidly and reach a new equilibrium state. The hydrogen produced by vaporization enters the first pressure reducing valve (16) through the second hydrogen valve (15) for pressure reduction. Then it mixes with the hydrogen from the first hydrogen valve (12) and enters the third channel of the temperature controller (19) to absorb heat. S73: After the two streams of hydrogen in the second and third channels of the temperature controller (19) reach the temperature required by the fuel cell (22), they enter the equalizer (20) for equalization and mixing. Then, they are depressurized by the second pressure reducing valve (21) and enter the fuel cell (22) to be converted into electrical energy after reaching the pressure required by the fuel cell (22). During the operation of the three operating modes, the circulating medium valve (24) is opened and the circulating pump (25) is started. The circulating medium in the circulating medium pipeline (23) first enters the cooling channel of the fuel cell (22) to absorb heat, and then enters the circulating pump (25) through the circulating medium valve (24) to be pressurized. After being pressurized, it enters the first channel of the temperature controller (19) to release heat, and finally returns to the cooling channel of the fuel cell (22) to absorb heat again, and repeats the cycle.

Images