A liquid hydrogen storage and supply system with low evaporation rate

Abstract

The application discloses a low-evaporation-rate liquid hydrogen storage and supply system, which comprises a first power generation type hydrogen heat exchanger, a second power generation type hydrogen heat exchanger and a liquid hydrogen storage tank, wherein a hydrogen liquefaction unit and a liquid hydrogen pressurizing unit are installed on the liquid hydrogen storage tank. The application utilizes conventional abandoned high-quality hydrogen cooling capacity for thermoelectric generation, has the advantages of no noise, high reliability, long service life and the like, and uses generated electric energy to reduce liquid hydrogen evaporation loss, greatly prolongs the storage time of liquid hydrogen medium, and improves the overall economy of the system. A new type of power generation type hydrogen heat exchanger is designed, efficient integration of multiple processes such as conversion of para-hydrogen, heat exchange of cold and heat sources and thermoelectric generation is realized, the system structure is simplified, and the system has the characteristics of significant light weight. In addition, the cold and heat sources with specific temperatures can also maintain the efficiency stability of the thermoelectric generation sheet. According to the operation characteristics of the hydrogen storage and supply system and the difference of the thermoelectric generation, multiple operation modes are designed, the electric energy utilization rate is comprehensively improved, and the overall evaporation rate of the system is reduced.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy equipment technology, and in particular to a liquid hydrogen storage and supply system with a low evaporation rate. Background Technology

[0002] Hydrogen storage technology, serving as a bridge between hydrogen production and utilization, refers to the technology of storing hydrogen in a stable form of energy for convenient use. The main hydrogen storage technologies include high-pressure gaseous hydrogen storage and liquefaction hydrogen storage. High-pressure gaseous hydrogen storage involves storing gaseous hydrogen at pressure above its critical temperature through compression. Gas tanks are typically used as containers, offering advantages such as low energy consumption, low cost, and rapid hydrogen filling and releasing. Furthermore, hydrogen release can be controlled via pressure-reducing valves. However, the hydrogen storage density of this technology is significantly affected by pressure, which is limited by the material of the storage tank. Liquefaction hydrogen storage involves compressing hydrogen gas and then cryogenically cooling it to 20K to liquefy it into liquid hydrogen, which is then stored in a specially designed insulated vacuum container. Compared to high-pressure gaseous hydrogen storage, cryogenic liquid hydrogen storage offers significantly higher mass and volumetric hydrogen storage densities, making it an ideal hydrogen storage method.

[0003] Liquid hydrogen storage faces two major technical challenges: First, hydrogen liquefaction consumes a large amount of energy, with actual engineering costs ranging from approximately 8-15 kWh / kg. Second, there is the issue of insulation in liquid hydrogen storage. Due to the large temperature difference between the liquid hydrogen inside the storage tank and the environment, high demands are placed on the selection of materials and design of the storage tank and its insulation. Despite these challenges, for small storage tanks with limited capacity, vacuum super-insulation or vacuum super-insulation with an external liquid nitrogen protective shield is typically used, resulting in an evaporation loss of approximately 0.4% / day. For large storage tanks with vacuum powder insulation, the evaporation loss is approximately 1% / day. In summary, liquefied hydrogen storage technology involves high-cost storage equipment and relatively complex safety technologies. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a liquid hydrogen storage and supply system with a low evaporation rate. This system can utilize the cooling capacity of hydrogen to generate electricity through a power generation hydrogen heat exchanger. At the same time, several different operating modes are designed according to the system's operating characteristics, which significantly reduces the evaporation rate of the liquid hydrogen storage and supply system.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A liquid hydrogen storage and supply system with a low evaporation rate includes a first power-generating hydrogen heat exchanger, a second power-generating hydrogen heat exchanger, and a liquid hydrogen storage tank. The liquid hydrogen storage tank is equipped with a hydrogen liquefaction unit and a liquid hydrogen pressurization unit. The input end of the first power-generating hydrogen heat exchanger is connected to an air inlet pipe and a hydrogen pipe a, respectively. The output end of the first power-generating hydrogen heat exchanger is connected to a hydrogen vent pipe and an air discharge pipe, respectively. The hydrogen pipe a is connected to the hydrogen liquefaction unit.

[0007] The input end of the second power generation type hydrogen heat exchanger is connected to hydrogen pipeline b and air supply pipeline respectively. The air supply pipeline is connected to the air intake pipeline, and hydrogen pipeline b is connected to the liquid hydrogen storage tank. The output end of the second power generation type hydrogen heat exchanger is connected to the hydrogen power system.

[0008] Preferably, the liquid hydrogen storage tank includes an inner shell and an outer shell, the liquid hydrogen pressurization unit is located between the inner shell and the outer shell, and a vacuum is drawn between the inner shell and the outer shell to achieve efficient heat insulation of the tank.

[0009] Preferably, the hydrogen liquefaction unit includes a hydrogen reliquefaction pipeline connected to the inner shell of the liquid hydrogen storage tank, and a hydrogen liquefaction valve and a cryogenic chiller are respectively installed on the hydrogen reliquefaction pipeline.

[0010] Preferably, the liquid hydrogen pressurization unit includes a liquid hydrogen circulation pipeline connected to the inner shell of the liquid hydrogen storage tank, and a liquid hydrogen pressurization pump and a throttle valve are respectively installed on the liquid hydrogen circulation pipeline.

[0011] Preferably, both the first and second power generation hydrogen heat exchangers include a cold fluid hydrogen channel and a hot fluid air channel. The cold fluid hydrogen channel is provided with a cold end of a power generation chip, and the hot fluid air channel is provided with a hot end of a power generation chip. The cold end and the hot end of the power generation chip are respectively connected to a P-type semiconductor and an N-type semiconductor through conductive sheets. A high thermal conductivity material is coated between the cold fluid hydrogen channel and the cold end of the power generation chip, and between the hot fluid air channel and the hot end of the power generation chip, to reduce contact thermal resistance.

[0012] Preferably, the cold fluid hydrogen channel is filled with a secondary positive hydrogen conversion catalyst, which is coated on the surface of a high thermal conductivity metal medium to increase the contact area.

[0013] Preferably, an air compressor, a dryer, and a second air valve are installed on the air intake pipe, and the dryer is filled with a highly absorbent adsorbent.

[0014] Preferably, hydrogen vent valve, first air valve and liquid hydrogen shut-off valve are installed on hydrogen pipeline a, air supply pipeline and hydrogen pipeline b respectively, and the first power generation hydrogen heat exchanger, cryogenic chiller, second power generation hydrogen heat exchanger and liquid hydrogen booster pump are connected to the energy storage unit through power lines.

[0015] Preferably, the hydrogen power system is a hydrogen engine or a hydrogen-oxygen fuel cell.

[0016] Preferably, the hot and cold fluids inside the first and second power generation hydrogen heat exchangers both adopt a counter-current heat exchange structure to improve heat exchange efficiency.

[0017] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention utilizes the high-quality hydrogen cooling capacity from conventional waste for thermoelectric power generation, which has advantages such as noiselessness, high reliability, and long lifespan. The generated electricity is used to reduce liquid hydrogen evaporation losses, significantly extending the storage time of liquid hydrogen and improving the overall economic efficiency of the system. A novel power-generating hydrogen heat exchanger is designed, achieving efficient integration of multiple processes such as positive hydrogen conversion, heat exchange between cold and heat sources, and thermoelectric power generation. This simplifies the system structure and exhibits significant lightweight characteristics. Furthermore, the cold and heat sources at specific temperatures can maintain the stable efficiency of the thermoelectric power generation unit. Based on the operating characteristics of the hydrogen storage and supply system and the differences in thermoelectric power generation, multiple operating modes are designed to comprehensively improve energy utilization and reduce the overall evaporation rate of the system. Attached Figure Description

[0018] To illustrate the technical solutions in the embodiments of the present invention or the prior art more specifically and intuitively, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0019] Figure 1 This is a schematic diagram of the structure of a liquid hydrogen storage and supply system with a low evaporation rate according to the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of the power generation type hydrogen heat exchanger of the present invention.

[0021] In the diagram: 1. Hydrogen venting pipeline; 2. Hydrogen venting valve; 3. First power generation type hydrogen heat exchanger; 4. Hydrogen reliquefaction pipeline; 5. Hydrogen liquefaction valve; 6. Cryogenic chiller; 7. Hydrogen pipeline b; 8. Liquid hydrogen shut-off valve; 9. Liquid hydrogen pump; 10. Second power generation type hydrogen heat exchanger; 11. Hydrogen power system; 12. Air intake pipeline; 13. Air supply pipeline; 14. Air exhaust pipeline; 15. Air compressor; 16. Dryer; 17. First air valve; 18. Second air valve; 19. Power line; 20. Liquid hydrogen circulation pipeline; 21. Liquid hydrogen booster pump; 22. Throttling valve; 23. Inner shell of liquid hydrogen storage tank; 24. Outer shell of liquid hydrogen storage tank; 25. Cold fluid hydrogen channel; 26. Neutral hydrogen conversion catalyst; 27. Cold end of power generation chip; 28. P-type semiconductor; 29. ​​N-type semiconductor; 30. Conductive sheet; 31. Hot end of power generation chip; 32. Hot fluid air channel. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] Reference Figure 1-2A liquid hydrogen storage and supply system with a low evaporation rate includes a hydrogen venting pipeline 1, a hydrogen venting valve 2, a first power-generating hydrogen heat exchanger 3, a hydrogen reliquefaction pipeline 4, a hydrogen liquefaction valve 5, a cryogenic chiller 6, a hydrogen pipeline b7, a liquid hydrogen shut-off valve 8, a liquid hydrogen pump 9, a second power-generating hydrogen heat exchanger 10, a hydrogen power system 11, an air intake pipeline 12, an air supply pipeline 13, an air exhaust pipeline 14, an air compressor 15, a dryer 16, a first air valve 17, a second air valve 18, a power cord 19, a liquid hydrogen circulation pipeline 20, a liquid hydrogen booster pump 21, a throttle valve 22, an inner shell of a liquid hydrogen storage tank 23, and an outer shell of a liquid hydrogen storage tank 24.

[0024] The first power generation type hydrogen heat exchanger 3 and the second power generation type hydrogen heat exchanger 10 include a cold fluid hydrogen channel 25, a secondary positive hydrogen conversion catalyst 26, a power generation plate cold end 27, a P-type semiconductor 28, an N-type semiconductor 29, a conductive plate 30, a power generation plate hot end 31, and a hot fluid air channel 32.

[0025] The hydrogen venting pipeline 1 is connected in sequence to the inner shell 23 of the liquid hydrogen storage tank, the hydrogen venting valve 2, and the cold fluid hydrogen channel 25 of the first power generation type hydrogen heat exchanger 3. It discharges the vapor BOG generated during liquid hydrogen storage and uses its sensible heat and secondary positive hydrogen conversion heat to generate electricity.

[0026] The hydrogen reliquefaction pipeline 4 is connected in sequence to the inner shell 23 of the liquid hydrogen storage tank, the hydrogen liquefaction valve 5, the cryogenic chiller 6, and the inner shell 23 of the liquid hydrogen storage tank. The cryogenic chiller 6 is used to reliquefy the vapor BOG generated during liquid hydrogen storage and transport it to the inner shell 23 of the liquid hydrogen storage tank for storage.

[0027] The hydrogen pipeline b7 is connected in sequence to the inner shell 23 of the liquid hydrogen storage tank, the liquid hydrogen shut-off valve 8, the liquid hydrogen pump 9, the cold fluid hydrogen channel 25 of the second power generation type hydrogen heat exchanger 10, and the hydrogen power system 11, so as to transport the liquid hydrogen medium to the hydrogen power system 11 and generate electricity by utilizing the sensible heat, latent heat and secondary positive hydrogen conversion heat of liquid hydrogen.

[0028] The front end of the air intake pipe 12 is connected to the air compressor 15 and the dryer 16, and the rear end is connected to the air supply pipe 13 and the air exhaust pipe 14 respectively; the air supply pipe 13 is connected in sequence to the first air valve 17, the hot fluid air passage 32 of the second power generation hydrogen heat exchanger 10, and the hydrogen power system 11; the air exhaust pipe 14 is connected in sequence to the second air valve 18 and the hot fluid air passage 32 of the first power generation hydrogen heat exchanger 3.

[0029] A stable temperature difference is formed between the cold fluid hydrogen channel 25 and the hot fluid air channel 32 in the first power generation hydrogen heat exchanger 3 and the second power generation hydrogen heat exchanger 10, so that electricity is generated while performing efficient heat exchange.

[0030] The first power-generating hydrogen heat exchanger 3 and the second power-generating hydrogen heat exchanger 10 both contain a cold fluid hydrogen channel 25 and a hot fluid air channel 32. The cold fluid hydrogen channel 25 contains a secondary positive hydrogen conversion catalyst 26, and a temperature difference type power generation plate is arranged between the two channels. The cold end 27 of the power generation plate is connected to the cold fluid hydrogen channel 25 to absorb cold energy, and the hot end 31 of the power generation plate is connected to the hot fluid air channel 32 to release heat. The cold end 27 and the hot end 31 of the power generation plate are directly equipped with P-type semiconductors 28 and N-type semiconductors 29 fixed by conductive sheets 30, forming an integral temperature difference type power generation plate.

[0031] A liquid hydrogen storage and supply system with a low evaporation rate has two operating modes, and the specific operating principles are as follows:

[0032] Mode 1

[0033] The liquid hydrogen storage and supply system is in a static state and does not supply liquid hydrogen to the outside. The liquid hydrogen storage tank discharges hydrogen gas generated by heat leakage to the outside. At this time, the first power generation type hydrogen heat exchanger 3 generates less electricity.

[0034] First, assume that all valves are closed and all devices are stopped.

[0035] (1) Open the second air valve 18, start the air compressor 15, and the outside air enters the air intake pipe 12. Under the action of the air compressor 15, it passes through the dryer 16 and enters the air exhaust pipe 14. Then it passes through the second air valve 18 and enters the hot fluid air passage 32 of the first power generation hydrogen heat exchanger 3, and then is vented.

[0036] (2) Open the hydrogen vent valve 2, and the low-temperature hydrogen in the upper gas phase space of the inner shell 23 of the liquid hydrogen storage tank enters the hydrogen vent pipeline 1. Then, it enters the cold fluid hydrogen channel 25 of the first power generation hydrogen heat exchanger 3 through the hydrogen vent valve 2, releases cold energy to generate electricity, and then vents.

[0037] (3) The electrical energy generated by the first power generation type hydrogen heat exchanger 3 is transmitted to the liquid hydrogen booster pump 21 through the power line 19. The liquid hydrogen booster pump 21 is then started, and the liquid hydrogen in the lower liquid phase space of the inner shell 23 of the liquid hydrogen storage tank is transported to the liquid hydrogen circulation pipeline 20. After being throttled by the throttle valve 22, it forms subcooled liquid hydrogen, which then re-enters the inner shell 23 of the liquid hydrogen storage tank, thus alleviating the hydrogen vaporization loss caused by the internal thermal stratification of the inner shell 23 of the liquid hydrogen storage tank.

[0038] Mode 2

[0039] The liquid hydrogen storage and supply system supplies liquid hydrogen to the outside, and a large amount of liquid hydrogen is vaporized. At this time, the second power generation type hydrogen heat exchanger 10 generates a lot of electricity, which can be used for hydrogen reliquefaction.

[0040] First, assume that all valves are closed and all devices are stopped.

[0041] (1) Open the first air valve 17 and start the air compressor 15. External air enters the air intake pipe 12. Under the action of the air compressor 15, it passes through the dryer 16 and enters the air supply pipe 13. Then it enters the hot fluid air channel 32 of the second power generation hydrogen heat exchanger 10 to absorb heat and finally enters the hydrogen power system 11 to generate power.

[0042] (2) Open the liquid hydrogen shut-off valve 8 and start the liquid hydrogen pump 9. The liquid hydrogen medium from the inner shell 23 of the liquid hydrogen storage tank passes through the liquid hydrogen shut-off valve 8 and the liquid hydrogen pump 9 in sequence, and then enters the cold fluid hydrogen channel 25 of the second power generation type hydrogen heat exchanger 10 to release cold energy and generate electricity, and then enters the hydrogen power system 11 to generate power.

[0043] (3) Part of the electrical energy generated by the second power generation type hydrogen heat exchanger 10 is transmitted to the liquid hydrogen booster pump 21 through the power line 19. The liquid hydrogen booster pump 21 is then started, and the liquid hydrogen in the lower liquid phase space of the inner shell 23 of the liquid hydrogen storage tank is transported to the liquid hydrogen circulation pipeline 20. After being throttled by the throttle valve 22, it forms subcooled liquid hydrogen, which then re-enters the inner shell 23 of the liquid hydrogen storage tank, thus alleviating the hydrogen vaporization loss caused by the internal thermal stratification of the inner shell 23 of the liquid hydrogen storage tank.

[0044] (4) Another part of the electrical energy generated by the second power generation type hydrogen heat exchanger 10 is transmitted to the cryogenic chiller 6 through the power line 19. Then the hydrogen liquefaction valve 5 is opened and the cryogenic chiller 6 is started. The cryogenic hydrogen in the upper gas phase space of the inner shell 23 of the liquid hydrogen storage tank enters the hydrogen reliquefaction pipeline 4 and is liquefied under the action of the cryogenic chiller 6. Then it continues to enter the inner shell 23 of the liquid hydrogen storage tank for storage.

[0045] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A liquid hydrogen storage and supply system with a low evaporation rate, comprising a first power-generating hydrogen heat exchanger (3), a second power-generating hydrogen heat exchanger (10), and a liquid hydrogen storage tank, characterized in that, The liquid hydrogen storage tank is equipped with a hydrogen liquefaction unit and a liquid hydrogen pressurization unit. The input end of the first power generation type hydrogen heat exchanger (3) is connected to an air inlet pipe (12) and a hydrogen pipe a, respectively. The output end of the first power generation type hydrogen heat exchanger (3) is connected to a hydrogen exhaust pipe (1) and an air discharge pipe (14), respectively. The hydrogen pipe a is connected to the hydrogen liquefaction unit. The input end of the second power generation type hydrogen heat exchanger (10) is connected to a hydrogen pipeline b (7) and an air supply pipeline (13). The air supply pipeline (13) is connected to an air intake pipeline (12), and the hydrogen pipeline b (7) is connected to a liquid hydrogen storage tank. The output end of the second power generation type hydrogen heat exchanger (10) is connected to a hydrogen power system (11). The first power generation hydrogen heat exchanger (3) and the second power generation hydrogen heat exchanger (10) both include a cold fluid hydrogen channel (25) and a hot fluid air channel (32). The cold fluid hydrogen channel (25) is provided with a cold end (27) of a power generation chip, and the hot fluid air channel (32) is provided with a hot end (31) of a power generation chip. The cold end (27) and the hot end (31) of the power generation chip are respectively connected to a P-type semiconductor (28) and an N-type semiconductor (29) through a conductive sheet (30). A high thermal conductivity material is coated between the cold fluid hydrogen channel (25) and the cold end (27) of the power generation chip, and between the hot fluid air channel (32) and the hot end (31) of the power generation chip. The cold fluid hydrogen channel (25) is filled with a secondary positive hydrogen conversion catalyst (26). Hydrogen vent valve (2), first air valve (17) and liquid hydrogen shut-off valve (8) are installed on hydrogen pipeline a, air supply pipeline (13) and hydrogen pipeline b (7) respectively. The first power generation hydrogen heat exchanger (3), cryogenic chiller (6), second power generation hydrogen heat exchanger (10) and liquid hydrogen booster pump (21) are connected to the energy storage unit through power line (19). The hydrogen power system (11) is a hydrogen engine or a hydrogen-oxygen fuel cell.

2. The liquid hydrogen storage and supply system with a low evaporation rate according to claim 1, characterized in that, The liquid hydrogen storage tank includes an inner shell (23) and an outer shell (24). The liquid hydrogen pressurization unit is located between the inner shell (23) and the outer shell (24). A vacuum is drawn between the inner shell (23) and the outer shell (24).

3. A liquid hydrogen storage and supply system with a low evaporation rate according to claim 2, characterized in that, The hydrogen liquefaction unit includes a hydrogen reliquefaction pipeline (4) connected to the inner shell (23) of the liquid hydrogen storage tank. A hydrogen liquefaction valve (5) and a cryogenic chiller (6) are installed on the hydrogen reliquefaction pipeline (4).

4. A liquid hydrogen storage and supply system with a low evaporation rate according to claim 3, characterized in that, The liquid hydrogen pressurization unit includes a liquid hydrogen circulation pipeline (20) connected to the inner shell (23) of the liquid hydrogen storage tank. A liquid hydrogen pressurization pump (21) and a throttle valve (22) are installed on the liquid hydrogen circulation pipeline (20).

5. A liquid hydrogen storage and supply system with a low evaporation rate according to claim 4, characterized in that, An air compressor (15), a dryer (16), and a second air valve (18) are respectively installed on the air intake pipe (12). The dryer (16) is filled with a highly absorbent adsorbent.

6. A liquid hydrogen storage and supply system with a low evaporation rate according to claim 5, characterized in that, The hot and cold fluids inside the first power generation type hydrogen heat exchanger (3) and the second power generation type hydrogen heat exchanger (10) both adopt a counter-current heat exchange structure.

Images