Liquid nitrogen and liquid neon combined cold storage system applied to liquid hydrogen energy storage

Abstract

The utility model provides a liquid nitrogen and liquid neon combined cold storage system applied to liquid hydrogen energy storage and a cold storage method, and particularly relates to the technical field of low-temperature energy storage, the liquid nitrogen and liquid neon combined cold storage system applied to liquid hydrogen energy storage comprises a cold storage unit, the cold storage unit comprises a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger, when the hydrogen is liquefied again, the high-pressure liquid neon, the normal-pressure liquid neon and the normal-pressure liquid nitrogen of the cold storage unit are used for providing pre-cooling cold for the hydrogen, the high-pressure liquid neon, the normal-pressure liquid neon and the normal-pressure liquid nitrogen of the cold storage unit are used as cold storage working media, the high-pressure liquid neon, the normal-pressure liquid neon and the normal-pressure liquid nitrogen of the cold storage unit are used for providing pre-cooling cold for the hydrogen when the hydrogen is liquefied again. And gradient heat exchange is used for cold release and cold storage, so that a cold release temperature area of liquid hydrogen can be matched to the maximum extent, high-quality cold energy of 27K, 40K and 77K low-temperature areas is recycled, the heat exchange temperature difference is reduced, and the low-temperature high-quality cold energy recycling rate is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of low-temperature energy storage, and in particular to a liquid nitrogen and liquid neon combined cold storage system applied to liquid hydrogen energy storage. Background Art

[0002] Liquid hydrogen has the advantages of high storage density, low transportation cost and low working pressure. It has gradually become an effective means of large-scale energy storage over long distances, with large capacity and for a long time, as well as coupling water electrolysis to produce hydrogen to absorb abandoned electricity, smooth fluctuations and shift peaks to fill valleys.

[0003] Since the hydrogen liquefaction temperature is as low as 20K, the power consumption of the liquefaction process reaches 12-15kWh / kg. The lower the temperature of the hydrogen, the greater the cooling exergy and the greater the irreversibility. Therefore, before re-vaporizing and using the hydrogen, certain measures must be taken to reduce the waste of high-quality cooling exergy to improve the efficiency and energy utilization of the entire process, so as to achieve cost reduction and efficiency improvement.

[0004] At present, most of the liquid hydrogen energy storage systems are about coupling multiple heat exchange units or cold energy power generation devices. For example, patent CN114232005A discloses a storage method for coupling water electrolysis hydrogen production, liquid nitrogen pre-cooling hydrogen liquefaction system, liquid hydrogen-liquid nitrogen and liquid hydrogen-coolant heat exchange system, and air separation system. CN 218888212 U discloses a distributed liquid hydrogen energy storage system that uses photovoltaic, wind power, and tidal energy to electrolyze water to produce hydrogen, and uses a liquid neon expansion generator set to recover liquid hydrogen cold energy. Since the method of using multiple cold energy power generation devices will increase the complexity of the entire system, and the output energy is subject to the parameters of each node, it is difficult to plan uniformly, and the current system using multiple heat exchange units cannot match the temperature zone below 77K of liquid hydrogen well.

[0005] In view of this, the utility model provides a liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage, which uses normal pressure liquid nitrogen, high pressure liquid neon and normal pressure liquid neon to match various temperature zones of liquid hydrogen, and can achieve high-quality cold energy recovery in the low temperature zone of liquid hydrogen. Utility Model Content

[0006] In order to solve the problem that the cold energy recovery system cannot recover the cold energy in the low temperature zone of liquid hydrogen, the utility model proposes a liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage.

[0007] The utility model is realized by the following technical solutions:

[0008] The utility model proposes a liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage, comprising a cold storage unit, a liquefaction unit and a power supply unit, wherein:

[0009] The cold storage unit comprises a first compressor, a first storage tank, a second storage tank, a third storage tank, a fourth storage tank, a fifth storage tank, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger and a fifth heat exchanger, one outlet end of the first storage tank is sequentially connected to a first heat exchange side of the first heat exchanger, a first heat exchange side of the second heat exchanger and the fifth storage tank, one outlet end of the second storage tank is sequentially connected to the first compressor, the second heat exchange side of the first heat exchanger, the first heat exchange side of the third heat exchanger and the fourth storage tank, another outlet end of the second storage tank is sequentially connected to the third heat exchange side of the first heat exchanger, the second heat exchange side of the third heat exchanger, the first heat exchange side of the fourth heat exchanger and the third storage tank, and the first heat exchange side of the fifth heat exchanger is connected to a carbon dioxide source;

[0010] The liquefaction unit includes a hydrogen production device, a precooling heat exchanger, a normal-parahydrogen converter, a final-stage heat exchanger and a liquid hydrogen storage tank;

[0011] The power supply unit includes a storage module and a power supply module;

[0012] When the cold storage unit stores cold, the outlet end of the hydrogen production device is sequentially connected to the first heat exchange side of the precooling heat exchanger, the positive-parahydrogen converter, the first heat exchange side of the final heat exchanger and the liquid hydrogen storage tank, and the outlet end of the liquid hydrogen storage tank is sequentially connected to the second heat exchange side of the fourth heat exchanger, the third heat exchanger of the third heat exchanger, the second heat exchange side of the second heat exchanger, the fourth heat exchange side of the first heat exchanger, the second heat exchange side of the fifth heat exchanger and the power supply module;

[0013] When the cold storage unit releases cold, the outlet end of the hydrogen production device is connected in sequence to the second heat exchange side of the fifth heat exchanger, the fourth heat exchange side of the first heat exchanger, the second heat exchange side of the second heat exchanger, the third heat exchange side of the third heat exchanger and the second heat exchange side of the fourth heat exchanger, the first heat exchange side of the final heat exchanger and the liquid hydrogen storage tank.

[0014] Furthermore, it also includes a circulation unit, which includes a second compressor and a first expander, and the outlet end of the second compressor is connected in sequence to the second heat exchange side of the precooling heat exchanger, the first expander, the second heat exchange side of the final stage heat exchanger, the third heat exchange side of the precooling heat exchanger, and is connected back to the inlet end of the second compressor.

[0015] Furthermore, a throttle valve is provided between the first heat exchange side of the final stage heat exchanger and the liquid hydrogen storage tank.

[0016] Furthermore, a third compressor is provided between the hydrogen production device and the first heat exchange side of the precooling heat exchanger and the fourth heat exchange side of the first heat exchanger.

[0017] Furthermore, the power supply module includes a hydrogen steam turbine and a fuel cell stack, and the first heat exchange side of the fifth heat exchanger is connected to the hydrogen steam turbine and the fuel cell stack in sequence.

[0018] Furthermore, a fourth compressor is provided between the storage module and the second heat exchange side of the fourth heat exchanger.

[0019] Furthermore, the cold storage method of the liquid nitrogen and liquid neon combined cold storage system applied to liquid hydrogen energy storage comprises the following steps:

[0020] When the cold storage unit stores cold, the liquid hydrogen in the storage module releases cold through the second heat exchange side of the fourth heat exchanger, the third heat exchange side of the third heat exchanger, the second heat exchange side of the second heat exchanger, the fourth heat exchange side of the first heat exchanger and the second heat exchange side of the fifth heat exchanger in turn. The nitrogen in the first storage tank is pre-cooled by the first heat exchanger and cooled again by the second heat exchanger in turn and converted into liquid nitrogen and stored in the fifth storage tank. After a part of the neon in the second storage tank is compressed by the first compressor, the high-pressure neon is pre-cooled by the first heat exchanger and cooled again by the third heat exchanger in turn and converted into high-pressure liquid neon and stored in the fourth storage tank. Another part of the neon in the second storage tank is pre-cooled by the first heat exchanger and cooled by the third and fourth heat exchangers and converted into normal-pressure liquid neon and stored in the third storage tank. Carbon dioxide is cooled by heat exchange with hydrogen through the fifth heat exchanger.

[0021] When the cold storage unit releases cold, the pressurized hydrogen passes through the first heat exchanger, the second heat exchanger, the third heat exchanger, and the fourth heat exchanger in turn to exchange heat with liquid nitrogen, normal pressure liquid neon, and high pressure liquid neon for step-by-step cooling, and then passes through the final heat exchanger for heat exchange and is converted into liquid hydrogen and stored in the liquid hydrogen storage tank.

[0022] Beneficial effects of the utility model:

[0023] (1) The liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage proposed in the utility model utilizes atmospheric pressure neon, high pressure neon and atmospheric pressure nitrogen to recover liquid hydrogen cold energy through cascade heat exchange, which can match the cold release temperature zone of liquid hydrogen to the maximum extent, utilize cascade cold storage to reduce the heat exchange temperature difference, and improve the high-quality cold energy recovery rate in the low-temperature zone. Finally, the recovered cold energy is used to cool the hydrogen when it is liquefied again, so as to increase the liquid hydrogen output and reduce the liquefaction power consumption.

[0024] (2) The liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage proposed in the utility model uses liquefied carbon dioxide as a supplementary working fluid to further recover the coldness of the high-temperature zone of liquid hydrogen, and pre-cools the high-temperature zone of the liquefied carbon dioxide or outputs it separately to the outside for power generation and refrigeration, thereby improving the utilization of cold energy.

[0025] (3) The cold storage unit of the liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage proposed in the utility model is an independent unit, and the recovered cold energy is stored in the form of liquid neon and liquid nitrogen, which can be suitable for long-term and long-distance deployment, and the system flexibility is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of the liquid nitrogen and liquid neon combined cold storage system applied to liquid hydrogen energy storage of the utility model;

[0027] Figure 2 It is a schematic diagram of the cold storage process of the liquid nitrogen and liquid neon combined cold storage system applied to liquid hydrogen energy storage of the utility model;

[0028] Figure 3 It is a schematic diagram of the cooling process of the liquid nitrogen and liquid neon combined cooling storage system applied to liquid hydrogen energy storage of the utility model;

[0029] Figure 4 for Figure 2 and Figure 3 Composite heat transfer curve of

[0030] In the figure: hydrogen production device 1, third compressor 2, precooling heat exchanger 3, normal-parahydrogen converter 4, final heat exchanger 5, second compressor 6, first expander 7, throttle valve 8, liquid hydrogen storage tank 9, storage module 10, fourth compressor 11, hydrogen steam turbine 12, fuel cell stack 13, first storage tank 14, second storage tank 15, third storage tank 16, fourth storage tank 17, fifth storage tank 18, fifth heat exchanger 19, first heat exchanger 20, second heat exchanger 21, third heat exchanger 22, fourth heat exchanger 23;

[0031] The realization of the purpose, functional features and advantages of the present invention will be further described in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] In order to more clearly and completely illustrate the technical solution of the present invention, the present invention is further described below in conjunction with the accompanying drawings.

[0033] Please refer to Figure 1-Figure 4 The utility model proposes a liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage, including a cold storage unit, a liquefaction unit and a power supply unit, wherein:

[0034] It includes a cold storage unit, a liquefaction unit and a power supply unit, wherein:

[0035] The cold storage unit includes a first compressor, a first storage tank 14, a second storage tank 15, a third storage tank 16, a fourth storage tank 17, a fifth storage tank 18, a first heat exchanger 20, a second heat exchanger 21, a third heat exchanger 22, a fourth heat exchanger 23 and a fifth heat exchanger 19, one outlet end of the first storage tank 14 is sequentially connected to a first heat exchange side of the first heat exchanger 20, a first heat exchange side of the second heat exchanger 21 and the fifth storage tank 18, one outlet end of the second storage tank 15 is sequentially connected to the first compressor, the second heat exchange side of the first heat exchanger 20, the first heat exchange side of the third heat exchanger 22 and the fourth storage tank 17, the other outlet end of the second storage tank 15 is sequentially connected to the third heat exchange side of the first heat exchanger 20, the second heat exchange side of the third heat exchanger 22, the first heat exchange side of the fourth heat exchanger 23 and the third storage tank 16, and the first heat exchange side of the fifth heat exchanger 19 is connected to a carbon dioxide source;

[0036] The liquefaction unit includes a hydrogen production device 1, a precooling heat exchanger 3, a normal-parahydrogen converter 4, a final-stage heat exchanger 5 and a liquid hydrogen storage tank 9;

[0037] The power supply unit includes a storage module 10 and a power supply module;

[0038] When the cold storage unit stores cold, the outlet end of the hydrogen production device 1 is sequentially connected to the first heat exchange side of the precooling heat exchanger 3, the normal-parahydrogen converter 4, the first heat exchange side of the final heat exchanger 5 and the liquid hydrogen storage tank 9, and the outlet end of the liquid hydrogen storage tank 9 is sequentially connected to the second heat exchange side of the fourth heat exchanger 23, the third heat exchange side of the third heat exchanger 22, the second heat exchange side of the second heat exchanger 21, the fourth heat exchange side of the first heat exchanger 20, the second heat exchange side of the fifth heat exchanger 19 and the power supply module;

[0039] When the cold storage unit releases cold, the outlet end of the hydrogen production device 1 is connected in sequence to the second heat exchange side of the fifth heat exchanger 19, the fourth heat exchange side of the first heat exchanger 20, the second heat exchange side of the second heat exchanger 21, the third heat exchange side of the third heat exchanger 22 and the second heat exchange side of the fourth heat exchanger 23, the first heat exchange side of the final stage heat exchanger 5 and the liquid hydrogen storage tank 9.

[0040] In this embodiment:

[0041] The first compressor is used to pressurize neon gas;

[0042] The liquid hydrogen storage tank 9 is used to store liquid hydrogen;

[0043] The precooling heat exchanger 3 is used for precooling hydrogen;

[0044] The final heat exchanger 5 is used to further cool the low-temperature hydrogen to convert it into liquid hydrogen;

[0045] The ortho-parahydrogen converter is filled with ortho-parahydrogen catalyst for completing the ortho-parahydrogen conversion;

[0046] The first heat exchanger 20, the second heat exchanger 21, the third heat exchanger 22 and the fourth heat exchanger 23 are used to recover low-temperature hydrogen and liquid hydrogen cold energy through heat exchange, and store the cold energy in the form of high-pressure liquid neon, normal-pressure liquid neon and normal-pressure liquid nitrogen;

[0047] The fifth heat exchanger 19 is used to recover the low-temperature hydrogen cold energy and store the low-temperature cold energy in the form of liquid carbon dioxide;

[0048] The first storage tank 14 and the second storage tank 15 are used to store nitrogen and neon respectively;

[0049] The third storage tank 16, the fourth storage tank 17 and the fifth storage tank 18 are used to store normal pressure liquid neon, high pressure liquid neon and normal pressure liquid nitrogen respectively;

[0050] The power supply module is used for hydrogen power generation;

[0051] In a specific embodiment, when hydrogen is initially liquefied, it will be precooled by the precooling heat exchanger 3, cooled again by the normal-parahydrogen converter 4 and the final heat exchanger 5, and converted into liquid hydrogen and stored in the liquid hydrogen storage tank 9. The liquid hydrogen storage tank 9 is filled into the user's storage module 10, and then the storage module 10 is stored on-site or transported to an area where electricity is needed. When electricity is needed, the liquid hydrogen and the low-temperature hydrogen will be heat exchanged by the fourth heat exchanger 23, the third heat exchanger 22, the second heat exchanger 21, the first heat exchanger 20, and the fifth heat exchanger 19 in turn, and the cold energy will be transferred to the high-pressure neon, atmospheric neon, atmospheric nitrogen and carbon dioxide. A part of the neon in the second storage tank 15 will be pressurized. , after being cooled by the first heat exchanger 20 and the third heat exchanger 22, it will be converted into high-pressure liquid neon and stored in the fourth storage tank 17, and another part of the neon in the second storage tank 15 will directly pass through the first heat exchanger 20, the third heat exchanger 22 and the fourth heat exchanger 23 for heat exchange and cooling, and be converted into normal-pressure liquid neon and stored in the third storage tank 16. The nitrogen in the first storage tank 14 will pass through the first heat exchanger 20 and the second heat exchanger 21 for heat exchange and cooling, and be converted into normal-pressure liquid nitrogen and stored in the fifth storage tank 18. Finally, the carbon dioxide in the fifth heat exchanger 19 can be stored separately to the outside after absorbing the cold energy of hydrogen. The process of converting nitrogen and neon into liquid nitrogen and liquid neon is the cold storage process of the cold storage unit;

[0052] When the hydrogen is liquefied again, the hydrogen will enter the first heat exchanger 20, the second heat exchanger 21, the third heat exchanger 22 and the fourth heat exchanger 23 in turn to exchange heat with high-pressure liquid neon, normal-pressure liquid neon and normal-pressure liquid nitrogen, and finally cool down to liquid hydrogen through the final heat exchanger 5 and store in the liquid hydrogen storage tank 9, while the liquid neon and liquid nitrogen are converted into neon and nitrogen and enter the first storage tank 14 and the second storage tank 15. The process of converting liquid neon and liquid nitrogen into nitrogen and neon is the cold release process of the cold storage unit. The cold storage unit, as an independent unit, stores and releases cold with liquid hydrogen and hydrogen respectively to circulate and transfer cold energy, thereby simplifying the entire energy storage system. At the same time, since the cold storage and release process of the cold storage unit in the entire system can be regarded as a thermal siphon cycle, especially in the high-pressure neon cycle, a high-pressure environment can be maintained to reduce the compression power consumption required for subsequent high-pressure neon. In one embodiment, high-pressure liquid hydrogen releases cold through the fourth heat exchanger 23, the third heat exchanger 22, the second heat exchanger 21, and the first heat exchanger 20 in sequence. In the first heat exchanger 20, atmospheric pressure nitrogen, high-pressure neon, and atmospheric pressure neon are cooled to about 77-78K. In the second heat exchanger 21, atmospheric pressure nitrogen is cooled to obtain liquid nitrogen. In the third heat exchanger 22, the incoming 77K high-pressure neon gas and atmospheric pressure neon gas are cooled to 40K to obtain high-pressure liquid neon (generally 1.465MPa high-pressure liquid neon). In the fourth heat exchanger 23, 40K atmospheric pressure neon is cooled to obtain liquid nitrogen. The hydrogen is cooled to 27K to obtain atmospheric pressure liquid neon. When the next liquefaction is performed, the pressurized hydrogen is cooled by atmospheric pressure liquid nitrogen, high pressure liquid neon, and atmospheric pressure liquid neon in turn using the recovered 77K, 40K, and 27K cold. The utility model uses atmospheric pressure neon, high pressure neon, and atmospheric pressure nitrogen to recover the cold energy of liquid hydrogen, which can match the cold release temperature zone of liquid hydrogen to the maximum extent, uses stepped cold storage to reduce the heat exchange temperature difference, and improves the high-quality cold energy recovery rate in the low-temperature zone. Finally, the recovered cold energy is used to cool the hydrogen when it is liquefied again, so as to increase the output of liquid hydrogen and reduce the power consumption of liquefaction.

[0053] In one embodiment, the working fluid may be selected or the temperature and pressure may be adjusted according to the specific situation, and different temperature zones may be set to maximize the recovery and utilization of the high-quality cold energy of liquid hydrogen while improving the recovery efficiency and reducing the cost.

[0054] Furthermore, it also includes a circulation unit, which includes a second compressor 6 and a first expander 7. The outlet end of the second compressor 6 is connected in sequence to the second heat exchange side of the precooling heat exchanger 3, the first expander 7, the second heat exchange side of the final heat exchanger 5, the third heat exchange side of the precooling heat exchanger 3, and is connected back to the inlet end of the second compressor 6.

[0055] In this embodiment:

[0056] The second compressor 6 and the first expander 7 are used for helium refrigeration;

[0057] In a specific embodiment, the fourth heat exchange side of the precooling heat exchanger 3 is connected to a nitrogen source, which provides cold energy for the hydrogen in the precooling heat exchanger 3. The second compressor 6, the first expander 7, the precooling heat exchanger 3 and the final heat exchanger 5 form a helium refrigeration circuit, and cool the hydrogen in the precooling heat exchanger 3 and the final heat exchanger 5, respectively, so that the hydrogen can be converted into liquid hydrogen.

[0058] In one embodiment, due to the irreversible heat transfer loss during the cold storage and release process, the cold energy obtained from one cold storage is insufficient to cool the hydrogen to the liquefaction temperature. Therefore, the helium refrigeration circuit of the circulation unit is required to provide cold energy for further liquefaction, or the cold energy of the liquid hydrogen is recovered multiple times by the cold storage unit, and then the cold storage unit is used to cool the hydrogen to reduce the burden on the circulation unit.

[0059] Furthermore, a throttle valve 8 is provided between the first heat exchange side of the final stage heat exchanger 5 and the liquid hydrogen storage tank 9 .

[0060] In this embodiment:

[0061] The throttle valve 8 is used for throttling and reducing the pressure of liquid hydrogen;

[0062] In a specific embodiment, the throttle valve 8 is arranged between the final stage heat exchanger 5 and the liquid hydrogen storage tank 9, so that the cooled low-temperature hydrogen is further throttled and depressurized to obtain liquid hydrogen which is stored in the liquid hydrogen storage tank 9, so as to facilitate the subsequent filling of liquid hydrogen into the storage module 10 for subsequent power generation.

[0063] Furthermore, a third compressor 2 is provided between the hydrogen production device 1 and the first heat exchange side of the precooling heat exchanger 3 and the fourth heat exchange side of the first heat exchanger 20 .

[0064] In this embodiment:

[0065] The third compressor 2 is used to compress hydrogen;

[0066] In a specific implementation, the third compressor 2 pressurizes the hydrogen, and the high-pressure hydrogen is more easily cooled and converted into liquid hydrogen after entering the pre-cooling heat exchanger 3 and the final-stage heat exchanger 5 .

[0067] Furthermore, the power supply module includes a hydrogen steam turbine 12 and a fuel cell stack 13, and a first heat exchange side of the fifth heat exchanger 19 is connected to the hydrogen steam turbine 12 and the fuel cell stack 13 in sequence.

[0068] In this embodiment:

[0069] The hydrogen steam turbine 12 is used to recover hydrogen pressure to generate electricity;

[0070] The fuel cell stack 13 is used for hydrogen reaction to generate electricity;

[0071] In a specific embodiment, high-pressure hydrogen will drive the hydrogen turbine 12 to generate power, releasing the pressure potential energy maintained by compression at low temperature. After passing through the hydrogen turbine 12, the high-pressure hydrogen enters the fuel cell stack 13 to react and generate power.

[0072] Furthermore, a fourth compressor 11 is provided between the storage module 10 and the second heat exchange side of the fourth heat exchanger 23 .

[0073] In this embodiment:

[0074] The fourth compressor 11 is used for compressing cryogenic hydrogen or liquid hydrogen;

[0075] In a specific embodiment, the fourth compressor 11 compresses low-temperature hydrogen and liquid hydrogen, and can use smaller compression work to maintain the pressure potential energy of low-temperature hydrogen and liquid hydrogen in a low-temperature environment. When the temperature is subsequently restored, greater expansion work can be obtained, thereby increasing the power of the hydrogen turbine 12 and obtaining more electricity.

[0076] Furthermore, the cold storage method of the liquid nitrogen and liquid neon combined cold storage system applied to liquid hydrogen energy storage comprises the following steps:

[0077] When the cold storage unit stores cold, the liquid hydrogen in the storage module 10 sequentially passes through the second heat exchange side of the fourth heat exchanger 23, the third heat exchange side of the third heat exchanger 22, the second heat exchange side of the second heat exchanger 21, the fourth heat exchange side of the first heat exchanger 20 and the second heat exchange side of the fifth heat exchanger 19 to release cold. The nitrogen in the first storage tank 14 is sequentially pre-cooled by the first heat exchanger 20 and cooled again by the second heat exchanger 21 and converted into liquid nitrogen and stored in the fifth storage tank 18. After a part of the neon in the second storage tank 15 is compressed by the first compressor, the high-pressure neon is sequentially pre-cooled by the first heat exchanger 20 and cooled again by the third heat exchanger 22 and converted into high-pressure liquid neon and stored in the fourth storage tank 17. Another part of the neon in the second storage tank 15 is pre-cooled by the first heat exchanger 20 and cooled by the third heat exchanger 22 and the fourth heat exchanger 23 and converted into normal-pressure liquid neon and stored in the third storage tank 16. The carbon dioxide is heat-exchanged and cooled with the hydrogen through the fifth heat exchanger 19.

[0078] When the cold storage unit releases cold, the pressurized hydrogen passes through the first heat exchanger 20, the second heat exchanger 21, the third heat exchanger 22, and the fourth heat exchanger 23 in turn to exchange heat with liquid nitrogen, normal pressure liquid neon, and high pressure liquid neon for step-by-step cooling, and then passes through the final heat exchanger 5 for heat exchange and is converted into liquid hydrogen and stored in the liquid hydrogen storage tank 9.

[0079] In a specific implementation, when the cold storage unit releases cold, due to the existence of the carbon dioxide phase change temperature plateau, if all the cold capacity of the liquid carbon dioxide is used for hydrogen pre-cooling, a temperature crossover problem will occur. For example, reducing the carbon dioxide flow rate to achieve a reasonable heat exchange composite curve will not have a significant gain in the outlet temperature and flow rate of the cooled hydrogen. Therefore, under normal circumstances, it is usually considered to output the liquefied carbon dioxide separately, or connect it to an external liquid carbon dioxide energy storage and power generation, rather than using liquefied carbon dioxide to pre-cool the hydrogen. Of course, the heat exchange effect and cost can be comprehensively considered according to different working conditions, and the flow rate of carbon dioxide can be adjusted for pre-cooling. Using liquefied carbon dioxide as a supplementary working fluid can further recover the cold capacity of the high-temperature zone of liquid hydrogen.

[0080] Of course, the present utility model may have many other implementations. Based on the present implementation, other implementations obtained by ordinary technicians in this field without any creative work are all within the scope of protection of the present utility model.

Claims

1. A liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage, characterized in that: It includes a cold storage unit, a liquefaction unit and a power supply unit, wherein: The cold storage unit comprises a first compressor, a first storage tank, a second storage tank, a third storage tank, a fourth storage tank, a fifth storage tank, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger and a fifth heat exchanger, one outlet end of the first storage tank is sequentially connected to a first heat exchange side of the first heat exchanger, a first heat exchange side of the second heat exchanger and the fifth storage tank, one outlet end of the second storage tank is sequentially connected to the first compressor, the second heat exchange side of the first heat exchanger, the first heat exchange side of the third heat exchanger and the fourth storage tank, another outlet end of the second storage tank is sequentially connected to the third heat exchange side of the first heat exchanger, the second heat exchange side of the third heat exchanger, the first heat exchange side of the fourth heat exchanger and the third storage tank, and the first heat exchange side of the fifth heat exchanger is connected to a carbon dioxide source; The liquefaction unit includes a hydrogen production device, a precooling heat exchanger, a normal-parahydrogen converter, a final-stage heat exchanger and a liquid hydrogen storage tank; The power supply unit includes a storage module and a power supply module; When the cold storage unit stores cold, the outlet end of the hydrogen production device is sequentially connected to the first heat exchange side of the precooling heat exchanger, the positive-parahydrogen converter, the first heat exchange side of the final heat exchanger and the liquid hydrogen storage tank, and the outlet end of the liquid hydrogen storage tank is sequentially connected to the second heat exchange side of the fourth heat exchanger, the third heat exchanger of the third heat exchanger, the second heat exchange side of the second heat exchanger, the fourth heat exchange side of the first heat exchanger, the second heat exchange side of the fifth heat exchanger and the power supply module; When the cold storage unit releases cold, the outlet end of the hydrogen production device is connected in sequence to the second heat exchange side of the fifth heat exchanger, the fourth heat exchange side of the first heat exchanger, the second heat exchange side of the second heat exchanger, the third heat exchange side of the third heat exchanger and the second heat exchange side of the fourth heat exchanger, the first heat exchange side of the final heat exchanger and the liquid hydrogen storage tank.

2. The liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage according to claim 1 is characterized in that: It also includes a circulation unit, which includes a second compressor and a first expander. The outlet end of the second compressor is sequentially connected to the second heat exchange side of the precooling heat exchanger, the first expander, the second heat exchange side of the final heat exchanger, the third heat exchange side of the precooling heat exchanger, and is connected back to the inlet end of the second compressor.

3. The liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage according to claim 1 is characterized in that: A throttle valve is also provided between the first heat exchange side of the final stage heat exchanger and the liquid hydrogen storage tank.

4. The liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage according to claim 1 is characterized in that: A third compressor is also provided between the hydrogen production device and the first heat exchange side of the precooling heat exchanger and the fourth heat exchange side of the first heat exchanger.

5. The liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage according to claim 1 is characterized in that: The power supply module includes a hydrogen steam turbine and a fuel cell stack, and the second heat exchange side of the fifth heat exchanger is connected to the hydrogen steam turbine and the fuel cell stack in sequence.

6. The liquid nitrogen and liquid neon combined cold storage system for liquid hydrogen energy storage according to claim 1 is characterized in that: A fourth compressor is also provided between the storage module and the second heat exchange side of the fourth heat exchanger.

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