A liquid hydrogen recovery system

Abstract

The application discloses a liquid hydrogen recovery system, comprising: a conversion module, the conversion module comprising an ejector, a pressure-resistant shell and a para-hydrogen conversion coil pipe packaged in the pressure-resistant shell; a para-hydrogen conversion catalyst is filled in the para-hydrogen conversion coil pipe; the para-hydrogen conversion coil pipe has two inlets and one outlet; the pressure-resistant shell has one inlet and one outlet, and the ejector is connected to the outlet of the pressure-resistant shell; a storage module, the storage module comprising a liquid hydrogen recovery tank and a liquid hydrogen pump installed in the liquid hydrogen recovery tank; the evaporated hydrogen gas of the target liquid hydrogen storage tank is liquefied again by the conversion module and collected in the storage module. The application can concentrate the high-pressure exhaust gas of the liquid hydrogen storage tank and recover the liquid hydrogen by using the endothermic process of para-hydrogen conversion to construct the liquid hydrogen recovery system, thereby reducing the evaporation loss of the liquid hydrogen.

Description

Technical Field

[0001] This invention relates to the field of liquid hydrogen zero-evaporation storage technology, and more specifically to a mobile liquid hydrogen recovery device. Background Technology

[0002] Hydrogen energy, as a highly efficient, widely distributed, and promising new energy source, can generate heat through combustion to produce mechanical work in heat engines, serve as an energy material in fuel cells, or be converted into solid hydrogen for use as a structural material. Hydrogen energy is characterized by its high calorific value, non-toxicity, and lack of pollution, making it an important vehicle for achieving a green and low-carbon energy transition.

[0003] Cryogenic liquid hydrogen storage, which stores hydrogen in liquid form through a hydrogen liquefaction cycle, offers high hydrogen density and relatively good safety, making it a superior hydrogen storage option. Currently, hydrogen liquefaction cycles mainly include the Linde-Hampson system, the Claude system, the JT throttling liquefaction cycle, helium-cooled hydrogen liquefaction cycles, and hydrogen expansion-cooled hydrogen liquefaction cycles. However, hydrogen liquefaction consumes a significant amount of energy, requiring processes such as compression, precooling, heat exchange, turbine expansion, and throttling valve expansion. The energy consumed is approximately 15.2 kWh / kg, almost half the lower heating value produced by hydrogen combustion. To reduce liquid hydrogen loss and ensure the economic efficiency and safety of liquid hydrogen storage, how to safely, efficiently, and even achieve zero-evaporation storage of liquid hydrogen has always been an important research direction. After liquefaction, hydrogen is stored in liquid hydrogen storage tanks. Liquid hydrogen storage employs various insulation methods to passively suppress liquid hydrogen evaporation, including conventional external insulation, high-vacuum insulation, vacuum powder insulation, high-vacuum multilayer insulation, and cryogenic cold shield insulation. There are also active liquid hydrogen zero-evaporation storage technologies that utilize energy from refrigeration units to provide cooling for heat transfer. Currently, the connection between the hydrogen liquefaction unit and the liquid hydrogen storage tank is merely a simple physical pipeline connection. Furthermore, due to the low boiling point and high evaporation rate of liquid hydrogen, long-term storage always faces the risks of hydrogen evaporation and pressurization within the tank, as well as gaseous hydrogen leakage, posing certain safety hazards.

[0004] Patent application CN116123816A discloses a hydrogen liquefaction and zero-evaporation storage system. This system introduces cryogenic helium from a helium refrigeration circuit into a liquid hydrogen storage tank after cooling by an adjustable refrigeration unit. The system uses a cryogenic helium spiral pipeline to control the subcooling of the liquid hydrogen in the tank and to recondense the flash vapor. Patent application CN216202458U discloses a zero-evaporation liquid hydrogen storage tank. The tank has a refrigerator and condenser installed on its inner liner. It draws evaporated hydrogen vapor to the area where the refrigerator is located. Since the refrigerator and condenser are fixed, the drawn-in hydrogen vapor is captured and liquefied into liquid hydrogen upon contact with the condenser. The liquid hydrogen then drips back to the surface under gravity, achieving zero evaporation. Most patents require additional active refrigeration devices and pipelines, increasing equipment and operating costs. Therefore, reducing the cost of active cooling technology for evaporated hydrogen recovery is a pressing issue in the field of liquid hydrogen recovery and is of great significance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a liquid hydrogen recovery system that maximizes the recovery of liquid hydrogen without the need for an external cold source.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A liquid hydrogen recovery system, comprising:

[0008] The conversion module includes an ejector, a pressure-resistant housing, and a secondary-positive hydrogen conversion coil encapsulated in the pressure-resistant housing; the secondary-positive hydrogen conversion coil is filled with a secondary-positive hydrogen conversion catalyst; the secondary-positive hydrogen conversion coil has two inlets and one outlet; the pressure-resistant housing has one inlet and one outlet, and the ejector is connected to the outlet of the pressure-resistant housing;

[0009] The storage module includes a liquid hydrogen recovery tank and a liquid hydrogen pump installed inside the liquid hydrogen recovery tank; the evaporated hydrogen from the target liquid hydrogen storage tank is liquefied again and collected in the storage module through a conversion module;

[0010] The two inlets of the bis-positive hydrogen conversion coil are connected to the exhaust port of the target liquid hydrogen storage tank and the exhaust port of the liquid hydrogen recovery tank, respectively; the outlet of the bis-positive hydrogen conversion coil is connected to the ejector port of the ejector; the inlet of the pressure-resistant shell is connected to the liquid hydrogen pump, the outlet of the pressure-resistant shell is connected to the ejector inlet, and the outlet of the ejector is connected to the liquid inlet of the liquid hydrogen recovery tank.

[0011] The tert-orthohydrogen conversion coil is filled with a tert-orthohydrogen conversion catalyst. Through tert-orthohydrogen conversion, hydrogen is liquefied, and the liquefied hydrogen products are then collected in the storage module. This not only solves the safety hazards caused by heat leakage and pressurization explosion in liquid hydrogen storage tanks, but also utilizes the cold energy released during conversion to liquefy hydrogen, reducing additional cold energy input and lowering energy consumption.

[0012] The ejector includes a converging nozzle, a mixing chamber, and a diffuser. The converging nozzle is typically composed of a small orifice, and fluid ejection is achieved by controlling the velocity and pressure of the inlet fluid. The mixing chamber mixes the inlet fluid and the main fluid, achieving the required pressure and mixing effect through sufficient energy exchange. The diffuser is shaped like a Venturi tube, which thoroughly mixes the fluids and converts kinetic energy back into pressure energy. High-speed, high-energy liquid hydrogen fluid enters the converging nozzle through the ejector inlet. The jet then enters the mixing chamber through the converging nozzle. Due to the reduced nozzle cross-sectional area, the flow velocity increases, and the pressure decreases, forming a low-pressure region within the mixing chamber. This low-pressure region attracts low-pressure liquid hydrogen fluid into the ejector mixing chamber. Due to the impact and agitation of the high-pressure fluid, the two fluids mix and finally flow out from the diffuser, flowing into the liquid hydrogen recovery tank through a pipeline.

[0013] Furthermore, the tert-orthohydrogen conversion coil has a multi-layer serpentine structure. This multi-layer serpentine structure extends the path of the tert-orthohydrogen conversion, allowing for more complete release of cold energy, and the curved shape effectively reduces pipe resistance and improves transmission efficiency.

[0014] Furthermore, the mobile module includes a chassis and rollers. The chassis is used to mount and support the conversion module and the storage module, and the rollers enable the entire device to be moved, reducing the cost of laying a large number of pipelines and installing complex and expensive equipment for liquid hydrogen recovery. Through the mobile and detachable structure, the system can be moved quickly and operate continuously, improving work efficiency.

[0015] Furthermore, the secondary-positive hydrogen conversion coil is filled with a secondary-positive hydrogen conversion catalyst. Through secondary-positive hydrogen conversion, hydrogen is liquefied, and the liquefied hydrogen products are then collected in the storage module. This not only solves the safety hazards caused by heat leakage and pressurization explosion in liquid hydrogen storage tanks, but also utilizes the cold energy released during conversion to liquefy hydrogen, reducing additional cold energy input and lowering energy consumption.

[0016] Furthermore, the damping plate bundle consists of a fixed pulley, a fixed-length rope, and a low-center-of-gravity wave-damping plate. The fixed pulley and the low-center-of-gravity wave-damping plate are connected by the fixed-length rope. The fixed pulley changes the direction of the force, the low-center-of-gravity wave-damping plate resists liquid impact, and the fixed-length rope is used for fixing devices and transmitting tension. The overall structure ensures a stable liquid surface, reduces damage to the inner wall of the liquid, and reduces the heat generated by liquid hydrogen evaporation.

[0017] Furthermore, the pressure-resistant shell inlet is connected to a distributed configuration nozzle, which is a lotus-shaped diversion structure, and there are two of them. This ensures that liquid hydrogen enters the pressure-resistant shell evenly, reduces the impact of uneven temperature rise in the space on the low-temperature environment, and thus provides a stable low-temperature environment for the tert-orthohydrogen conversion.

[0018] Furthermore, the low-center-of-gravity baffle plate has a bottom-heavy, top-light structure with a circular bottom. In its upright state, the center of gravity is closest to the bottom of the liquid hydrogen recovery tank, and the center of gravity is always at its lowest when rotating. When an external force is applied, the line of action of gravity deviates from the fulcrum, and gravity generates a torque on the fulcrum, i.e., a resisting torque. As the tilt angle of the low-center-of-gravity baffle plate continuously increases, the offset of the line of action of gravity increases accordingly, and the resisting torque also increases accordingly, ultimately achieving a balance with the external force torque, thereby resisting external interference, ensuring a stable liquid surface, and reducing the generation of heat of vaporization of liquid hydrogen.

[0019] Furthermore, the secondary-to-positive hydrogen conversion catalyst is a porous catalyst, which can be a metal catalyst such as palladium, rhodium, iridium or an organic catalyst such as carbene, imine, etc., catalyzing the conversion of secondary hydrogen into solid particulate matter of positive hydrogen at low temperature without energy consumption, but is not limited to the above types.

[0020] Furthermore, the connecting pipes of the conversion module and the storage module are both equipped with switch valves.

[0021] Furthermore, the recovery storage tank is a detachable storage tank mainly composed of positive hydrogen, consisting of a liquid hydrogen vapor cold shield and an external insulation layer. The liquid hydrogen vapor cold shield provides a cold barrier for the tank body and does not require additional cold shield equipment. The external insulation layer provides thermal insulation protection for the tank body. Beneficial effects

[0022] 1. Utilizing the principle of cold release through tert-orthohydrogen conversion, the released cold energy is used to liquefy liquid hydrogen vapor, which is then collected in a liquid hydrogen recovery tank, maximizing the recovery of liquid hydrogen. The left-side pipeline of the tert-orthohydrogen converter coil is designed with a multi-layered serpentine structure, extending the path of the tert-orthohydrogen conversion and allowing for more complete cold energy release. The curved shape effectively reduces pipeline resistance and improves transmission efficiency. The conversion module itself provides cryogenic liquid hydrogen fluid, providing a low-temperature environment for tert-orthohydrogen conversion. It features a distributed nozzle configuration, which innovatively adopts a lotus-shaped structure and a three-dimensional layered delivery method, ensuring uniform spatial distribution of the incoming liquid hydrogen fluid, guaranteeing uniform temperature rise within the pressure-resistant shell, and reducing cold energy dissipation.

[0023] 2. The damping plate bundle, through the combination of low center of gravity baffles, fixed pulleys and fixed-length ropes, reduces liquid impact, ensures a stable liquid surface, and reduces the generation of heat of vaporization of liquid hydrogen. The leftmost and rightmost baffles serve as the first impact surface to resist liquid impact, further reducing damage to the inner wall of the container.

[0024] 3. This system reduces the cost of laying a large number of pipelines and installing complex and expensive equipment for liquid hydrogen recovery by using mobile devices and detachable structures, ensuring that the system can be moved quickly, operate continuously, and improve work efficiency. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort. In the drawings:

[0026] Figure 1 This is a schematic diagram of the portable liquid hydrogen recovery device of the present invention;

[0027] Figure 2 This is a schematic diagram of the conversion module structure of the present invention;

[0028] Figure 3 This is a schematic diagram of the storage module structure of the present invention;

[0029] Figure 4 This is a schematic diagram of the working of the damping plate bundle of the present invention;

[0030] Figure 5 This is a schematic diagram of the distributed nozzle structure of the present invention;

[0031] Wherein: 11-Neutral-positive hydrogen conversion coil; 12-Pressure-resistant shell; 101-Neutral-positive hydrogen conversion coil inlet; 102-Pressure-resistant shell inlet; 103-Neutral-positive hydrogen conversion coil outlet; 104-Pressure-resistant shell outlet; 105-Distributed configuration nozzle; 106-Contraction nozzle; 107-Mixing chamber; 108-Diffuser; 109-Ejector inlet; 110-Ejector drain port; 111-Ejector outlet; 112-Stop valve; 2 1-Liquid hydrogen recovery tank; 22-Damping plate bundle; 201-Liquid hydrogen recovery tank exhaust port; 202-Liquid hydrogen recovery tank outlet; 203-Liquid hydrogen recovery tank inlet; 204-Liquid hydrogen pump; 205-Fixed pulley; 206-Low center of gravity baffle plate; 207-Fixed length rope; 208-Liquid hydrogen vapor cooling shield; 209-External insulation layer; 301-Chassis; 302-Roller; 1061-Main pipeline; 1062-Medium pipeline; 1063-Small pipeline. Detailed Implementation

[0032] To enhance understanding of the present invention, the invention will be further described in detail below with reference to the accompanying drawings. These embodiments are only used to explain the invention and do not constitute a limitation on the scope of protection of the invention.

[0033] Figure 1The schematic diagram of the present invention is shown. A liquid hydrogen recovery system includes a conversion module and a storage module. To facilitate the movement of the liquid hydrogen recovery system, a mobile module can be added, on which the conversion module and the storage module are mechanically fixed.

[0034] The conversion module includes: a secondary-positive hydrogen conversion coil 11, a pressure-resistant shell 12, a secondary-positive hydrogen conversion coil inlet 101, a pressure-resistant shell inlet 102, a secondary-positive hydrogen conversion coil outlet 103, a pressure-resistant shell outlet 104, a distributed configuration nozzle 105, a converging nozzle 106, a mixing chamber 107, a diffuser 108, an ejector inlet 109, an ejector outlet 110, an ejector outlet 111, a shut-off valve 112, a large pipeline 1061, a medium pipeline 1062, and a small pipeline 1063.

[0035] The storage module includes: a liquid hydrogen recovery tank 21, a damping plate bundle 22, a liquid hydrogen recovery tank exhaust port 201, a liquid hydrogen recovery tank outlet 202, a liquid hydrogen recovery tank inlet 203, a liquid hydrogen pump 204, a fixed pulley 205, a low center of gravity baffle plate 206, a fixed length rope 207, a liquid hydrogen vapor cooling shield 208, an external insulation layer 209, and a shut-off valve.

[0036] The moving module includes: chassis 301 and wheels 302.

[0037] The present invention proposes a mobile liquid hydrogen recovery system, the specific working process of which is as follows:

[0038] Monitoring of existing liquid hydrogen storage tanks indicates that the secondary hydrogen content in long-term liquid hydrogen storage tanks can exceed 99%. Hydrogen is a diatomic molecule; based on the relative spin directions of the two hydrogen nuclei, a hydrogen molecule can be divided into ortho-hydrogen (Ortho-H) and para-hydrogen (Para-H). Normally, hydrogen is a mixture of ortho-hydrogen and para-hydrogen, and the equilibrium percentage between them depends only on temperature. Para-hydrogen is a more stable form at low temperatures; at the saturation temperature of 20.4 K for liquid hydrogen at one atmosphere, the para-hydrogen content is 99.82%. When deviating from the equilibrium concentration, ortho-hydrogen and para-hydrogen spontaneously interconvert, always accompanied by the release or absorption of heat during the conversion process.

[0039] Due to long-term storage, the external target liquid hydrogen storage tank experiences heat leakage, causing the temperature to rise. Liquid hydrogen evaporates, and the vapor rises. When the pipeline shut-off valve 112 is opened, the vapor enters the intermediate-positive hydrogen conversion coil 11 through the connection pipeline between the exhaust port of the target liquid hydrogen storage tank and the inlet 101 of the intermediate-positive hydrogen conversion coil. At the same time, liquid hydrogen vapor in the liquid hydrogen recovery tank 21 also enters the intermediate-positive hydrogen conversion coil 11 through the connection pipeline between the exhaust port 201 of the liquid hydrogen recovery tank and the inlet 101 of the intermediate-positive hydrogen conversion coil. The liquid hydrogen vapor at the inlet of the left serpentine tube comes into full contact with the intermediate-positive hydrogen conversion catalyst filled in the coil, resulting in intermediate-positive hydrogen conversion. The conversion releases cold energy, and the liquid hydrogen vapor at the inlet above the coil absorbs the cold energy and liquefies into liquid hydrogen. Since the intermediate-positive hydrogen conversion cannot be completely completed, the unliquefied liquid hydrogen vapor mixes with the liquid hydrogen and flows to the outlet 103 of the intermediate-positive hydrogen conversion coil. When the liquid hydrogen pump 204 is turned on, the cryogenic liquid hydrogen fluid is drawn from the bottom of the liquid hydrogen recovery tank 21 and flows from bottom to top. It is transported through pipelines and enters the pressure-resistant shell 12 through the liquid hydrogen recovery tank outlet 202. It then flows to the distributed configuration nozzle 105, which is lotus-shaped. The cryogenic liquid hydrogen fluid is sprayed evenly downwards through the large pipeline 1061, the medium pipeline 1062, and the small pipeline 1063, and finally flows out from the pressure-resistant shell outlet 104.

[0040] The pressure-resistant housing outlet 104 is connected to the ejector inlet 109. Liquid hydrogen cryogenic fluid flows to the contraction nozzle 106, which consists of a small orifice. The speed and pressure of the liquid hydrogen cryogenic fluid are controlled to achieve ejection. The liquid hydrogen cryogenic fluid is ejected into the mixing chamber 107, where a low-pressure region is formed. This low-pressure region attracts the liquid hydrogen and vapor mixture flowing from the tert-orthohydrogen conversion coil outlet 103. This mixture then enters the mixing chamber 107 through the connected ejector inlet 110. In the mixing chamber 107, two streams of liquid hydrogen fluid are mixed. Through continuous impact and stirring by the high-pressure liquid hydrogen cryogenic fluid, sufficient energy exchange is carried out. After reaching the required pressure and mixing effect, the mixture flows to the diffuser 108, which is shaped like a venturi tube. The diffuser 108 fully mixes the cryogenic liquid hydrogen fluid and converts the kinetic energy back into pressure energy. Finally, it flows out from the ejector outlet 111 and enters the liquid hydrogen recovery tank 21 through the inlet 203 of the connected liquid hydrogen recovery tank, completing the entire process. After passing through the liquid hydrogen pump 204, a new cycle begins.

[0041] In the damping plate bundle 22, the low-center-of-gravity baffle 206, when upright, has its center of gravity closest to the bottom contact point of the liquid hydrogen recovery tank 21, resulting in the lowest center of gravity. When an external force is applied, the line of action of gravity deviates from the fulcrum, generating a torque on the fulcrum, i.e., a resisting torque. As the tilt angle of the low-center-of-gravity baffle continuously increases, the deviation of the line of action of gravity increases accordingly, and the resisting torque also increases, ultimately achieving balance with the external force torque, thereby resisting external interference. During the operation and movement of the mobile liquid hydrogen recovery device, the low-center-of-gravity baffle 206 is impacted by the liquid in the positive direction, causing it to rotate around its axis in the positive direction. The fixed pulley 205 acts as a fulcrum, pulling the fixed-length rope 207. The rightmost low-center-of-gravity baffle 206, under the action of the fixed-length rope 207, is pulled to rotate around its axis in the opposite direction, resisting the liquid impact, and vice versa, ensuring a stable liquid surface, reducing the generation of heat from liquid hydrogen evaporation, and minimizing damage to the inner wall of the storage tank.

[0042] The above specific embodiments are only for illustrating the technical concept and structural features of the present invention, and are intended to enable those skilled in the art to implement them. However, the above content does not limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit and essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A liquid hydrogen recovery system, characterized by, include: The conversion module includes an ejector, a pressure-resistant housing, and a secondary-orthohydrogen conversion coil encapsulated in the pressure-resistant housing. The bis-orthohydrogen conversion coil has two inlets and one outlet; the pressure-resistant housing has one inlet and one outlet, and the ejector is connected to the outlet of the pressure-resistant housing; The storage module includes a liquid hydrogen recovery tank and a liquid hydrogen pump installed inside the liquid hydrogen recovery tank; the evaporated hydrogen from the target liquid hydrogen storage tank is liquefied again and collected in the storage module through a conversion module; The two inlets of the bis-positive hydrogen conversion coil are connected to the exhaust ports of the target liquid hydrogen storage tank and the liquid hydrogen recovery tank, respectively; the bis-positive hydrogen conversion coil is filled with a bis-positive hydrogen conversion catalyst; the outlet of the bis-positive hydrogen conversion coil is connected to the ejector port of the ejector; the inlet of the pressure-resistant shell is connected to the liquid hydrogen pump, the outlet of the pressure-resistant shell is connected to the ejector inlet, and the outlet of the ejector is connected to the liquid inlet of the liquid hydrogen recovery tank; A damping plate bundle is also provided inside the liquid hydrogen recovery tank; the damping plate bundle consists of a fixed pulley, a fixed-length rope and a low-center-of-gravity wave-damping plate; the low-center-of-gravity wave-damping plate is oscillatingly installed inside the liquid hydrogen recovery tank, and one or more low-center-of-gravity wave-damping plates constitute a oscillating unit, and the upper ends of two adjacent sets of oscillating units are connected by the fixed-length rope sleeved on the fixed pulley. The low-center-of-gravity baffle plate has a bottom-heavy and top-light structure. The bottom is circular. When it is upright, the center of gravity is closest to the contact point with the bottom of the liquid hydrogen recovery tank. The center of gravity is always the lowest when rotating. Vapor enters the intermediate-positive hydrogen conversion coil through the connecting pipe between the exhaust port of the target liquid hydrogen storage tank and the inlet of the intermediate-positive hydrogen conversion coil. Simultaneously, liquid hydrogen vapor in the liquid hydrogen recovery tank also enters the intermediate-positive hydrogen conversion coil through the connecting pipe between the exhaust port of the liquid hydrogen recovery tank and the inlet of the intermediate-positive hydrogen conversion coil. The intermediate-positive hydrogen conversion coil has a multi-layer serpentine structure. The liquid hydrogen vapor at the inlet of the left serpentine tube comes into full contact with the intermediate-positive hydrogen conversion catalyst filled in the coil, resulting in intermediate-positive hydrogen conversion. The conversion releases cold energy. The liquid hydrogen vapor at the inlet above the coil absorbs the cold energy and liquefies into liquid hydrogen. The unliquefied liquid hydrogen vapor mixes with the liquid hydrogen and flows to the outlet of the intermediate-positive hydrogen conversion coil.

2. The liquid hydrogen recovery system of claim 1, wherein, The secondary-positive hydrogen conversion catalyst is a porous catalyst.

3. The liquid hydrogen recovery system of claim 1, wherein, The pressure-resistant housing inlet is connected to a distributed configuration nozzle.

4. The liquid hydrogen recovery system of claim 3, wherein, The distributed nozzle configuration has a lotus-shaped diversion structure, and there are two of them, which ensures that liquid hydrogen enters the pressure-resistant shell evenly.

5. The liquid hydrogen recovery system of any one of claims 1-4, wherein, Also includes: A mobile module, which carries the conversion module and the storage module.

6. The liquid hydrogen recovery system of claim 5, wherein, The mobile module includes a chassis and rollers. The chassis is used to mount and support the conversion module and the storage module, and the rollers enable the overall movement of the device.

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