Hydrogen liquefaction device and method

Abstract

The invention relates to the technical field of liquid hydrogen, and discloses a hydrogen liquefying device and method.The device comprises a mixed refrigerant suction tank, a mixed refrigerant compressor, a mixed refrigerant cooler and a first heat exchanger which are communicated in sequence, and further comprises a mixed refrigerant throttling valve communicated with the first heat exchanger. The problems that in the prior art, hydrogen liquefaction efficiency is low, energy consumption is high, and equipment is complex are solved.

Description

Technical Field

[0001] This invention relates to the field of liquid hydrogen technology, specifically a hydrogen liquefaction device and method. Background Technology

[0002] Hydrogen energy is a clean secondary energy source with abundant supply, green and low-carbon characteristics, and wide applications. It is an important alternative energy source in the construction of future energy systems and is widely used in industries such as manufacturing and transportation. Currently, hydrogen energy plays an important role in the adjustment of my country's future energy structure and is a key development direction for strategic emerging industries and future industries.

[0003] Hydrogen can exist in three states: gaseous, liquid, and solid. At a pressure of 101 kPa and a temperature of -252.87℃, gaseous hydrogen can transform into colorless liquid hydrogen. Liquid hydrogen has significant advantages such as high storage density, high transportation efficiency, and low storage and transportation pressure. Transporting liquid hydrogen is 6 to 8 times more efficient than transporting gaseous hydrogen. From a technical perspective, cryogenic liquid hydrogen has a greater cost advantage and is the inevitable choice for large-scale hydrogen energy applications in the future. Currently, domestic liquid hydrogen technology is still in its early stages. Liquid hydrogen for civilian use is costly, inefficient, energy-intensive, and requires complex equipment. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a hydrogen liquefaction device and method, which solves the problems of low hydrogen liquefaction efficiency, high energy consumption and complex equipment in the prior art.

[0005] The technical solution adopted by the present invention to solve the above problems is:

[0006] A hydrogen liquefaction device includes a mixed refrigerant intake tank, a mixed refrigerant compressor, a mixed refrigerant cooler, and a first heat exchanger connected in sequence, and also includes a mixed refrigerant throttling valve connected to the first heat exchanger.

[0007] As a preferred technical solution, the first heat exchanger includes a first mixed refrigerant circulation channel, a second mixed refrigerant circulation channel, a mixed refrigerant cooler, the first mixed refrigerant circulation channel, a mixed refrigerant throttle valve, the second mixed refrigerant circulation channel, and a mixed refrigerant suction tank connected in sequence.

[0008] As a preferred technical solution, the system includes a circulating hydrogen refrigerant compressor, a hydrogen cooler, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a fifth heat exchanger, a first and second intermediate hydrogen converter, a third intermediate hydrogen converter, a liquid hydrogen storage tank, a third turbine expander, a feedstock hydrogen pipeline, and a liquid hydrogen product pipeline. The circulating hydrogen refrigerant compressor, hydrogen cooler, first heat exchanger, second heat exchanger, third heat exchanger, fourth heat exchanger, fifth heat exchanger, third turbine expander, liquid hydrogen storage tank, and liquid hydrogen product pipeline are connected in sequence. The connecting pipeline between the hydrogen cooler and the first heat exchanger is connected to the feedstock hydrogen pipeline. The first heat exchanger is connected to the first intermediate hydrogen converter, the second heat exchanger is connected to the second intermediate hydrogen converter, and the third heat exchanger is connected to the third intermediate hydrogen converter.

[0009] As a preferred technical solution, the first heat exchanger includes a first hydrogen flow channel and a second hydrogen flow channel; the second heat exchanger includes a third hydrogen flow channel and a fourth hydrogen flow channel; the third heat exchanger includes a fifth hydrogen flow channel and a sixth hydrogen flow channel; the fourth heat exchanger includes a seventh hydrogen flow channel; and the fifth heat exchanger includes an eighth hydrogen flow channel. The circulating hydrogen refrigerant compressor, the hydrogen cooler, the first hydrogen flow channel, the first and second hydrogen converter, the second hydrogen flow channel, the third hydrogen flow channel, the second and second hydrogen converter, the fourth hydrogen flow channel, the fifth hydrogen flow channel, the third and second hydrogen converter, the sixth hydrogen flow channel, the seventh hydrogen flow channel, the eighth hydrogen flow channel, and the third turbine expander are connected in sequence.

[0010] As a preferred technical solution, the fifth heat exchanger includes a fourth hydrogen flash vapor channel, the fourth heat exchanger includes a third hydrogen flash vapor channel, the second heat exchanger includes a second hydrogen flash vapor channel, and the first heat exchanger includes a first hydrogen flash vapor channel. The gas phase of the liquid hydrogen storage tank, the fourth hydrogen flash vapor channel, the third hydrogen flash vapor channel, the second hydrogen flash vapor channel, the first hydrogen flash vapor channel, and the circulating hydrogen refrigerant compressor are connected in sequence.

[0011] As a preferred technical solution, it includes a first turbine expander unit, a first hydrogen refrigerant pipeline, a first hydrogen expansion pipeline, and a fourth heat exchanger including a fourth expansion hydrogen flow channel. The connecting pipeline between the sixth and seventh hydrogen flow channels, the first hydrogen refrigerant pipeline, the first turbine expander unit, the first hydrogen expansion pipeline, and the fourth expansion hydrogen flow channel are connected in sequence.

[0012] As a preferred technical solution, it includes a second turbine expander, a second hydrogen refrigerant pipeline, a second hydrogen expansion pipeline, and a fifth heat exchanger including a fifth expansion hydrogen flow channel. The connecting pipeline between the seventh and eighth hydrogen flow channels, the second hydrogen refrigerant pipeline, the second turbine expander, the second hydrogen expansion pipeline, and the fifth expansion hydrogen flow channel are connected in sequence.

[0013] As a preferred technical solution, the fourth heat exchanger includes a fourth expansion hydrogen flow channel, the third heat exchanger includes a third expansion hydrogen flow channel, the second heat exchanger includes a second expansion hydrogen flow channel, the first heat exchanger includes a first expansion hydrogen flow channel, and the fifth expansion hydrogen flow channel, the fourth expansion hydrogen flow channel, the third expansion hydrogen flow channel, the second expansion hydrogen flow channel, the first expansion hydrogen flow channel, and the circulating hydrogen refrigerant compressor are connected in sequence.

[0014] As a preferred technical solution, the system includes a liquid nitrogen supply pipeline and a nitrogen pipeline. The second heat exchanger includes a liquid nitrogen vaporization channel, and the first heat exchanger includes a nitrogen reheating channel. The liquid nitrogen supply pipeline, the liquid nitrogen vaporization channel, the nitrogen reheating channel, and the nitrogen pipeline are connected in sequence.

[0015] A hydrogen liquefaction method uses the aforementioned hydrogen liquefaction device to liquefy hydrogen. The mixed refrigerant sequentially passes through a mixed refrigerant suction tank, a mixed refrigerant compressor, a mixed refrigerant cooler, a first mixed refrigerant circulation channel, a mixed refrigerant throttle valve, a second mixed refrigerant circulation channel, and the mixed refrigerant suction tank to provide cooling capacity of the mixed refrigerant to a first heat exchanger.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) The present invention has the advantages of high hydrogen liquefaction efficiency, low energy consumption and simple equipment;

[0018] (2) The hydrogen liquefaction device of the present invention is suitable for the needs of large-scale hydrogen liquefaction production. According to the characteristics of hydrogen liquefaction, the hydrogen precooling of the present invention adopts mixed refrigerant refrigeration and liquid nitrogen precooling. The circulating hydrogen refrigeration system is subcooled, and the cooling capacity at high temperature is supplied through the mixed refrigerant system and liquid nitrogen respectively, which reduces the energy consumption provided by the circulating hydrogen refrigeration. The raw material hydrogen is converted, cooled and liquefied by a three-stage positive and negative hydrogen converter, and the negative hydrogen content in the liquid hydrogen is ≥95%.

[0019] (3) The present invention sets up two-stage hydrogen expansion and liquid hydrogen turbine expansion to recover pressure energy. At the same time, due to the JT effect, the hydrogen flash vapor generated during the production of liquid hydrogen is added to the heat exchange network to further reduce energy consumption. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a hydrogen liquefaction device according to the present invention.

[0021] The labels and their corresponding names in the attached diagram are as follows: 1. Circulating hydrogen refrigerant compressor; 2. Hydrogen cooler; 3. First heat exchanger; 4. Second heat exchanger; 5. Third heat exchanger; 6. Fourth heat exchanger; 7. Fifth heat exchanger; 8. First anisotropic hydrogen converter; 9. Second anisotropic hydrogen converter; 10. Third anisotropic hydrogen converter; 11. First turbine expander unit; 12. Second turbine expander unit; 13. Liquid hydrogen storage tank; 14. Third turbine expander unit; 15. Liquid nitrogen supply line; 16. Mixed refrigerant suction tank; 17. Mixed refrigerant compressor; 18. Mixed refrigerant cooler; 19. Mixed refrigerant throttle valve; 20. Raw material hydrogen pipeline; 21. Liquid hydrogen product pipeline; 22. Nitrogen pipeline; 23. First hydrogen refrigerant pipeline; 24. First hydrogen expansion pipeline; 25. Second hydrogen refrigerant pipeline; 26. Second hydrogen expansion pipeline. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0023] Example 1

[0024] like Figure 1 As shown, an apparatus for hydrogen liquefaction using mixed refrigerant refrigeration and liquid nitrogen precooling includes a circulating hydrogen refrigerant compressor, a hydrogen cooler, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a fifth heat exchanger, a first and second intermediate hydrogen converter, a third and second intermediate hydrogen converter, a first turbine expander unit, a second turbine expander unit, a liquid hydrogen storage tank, a third turbine expander unit, a liquid nitrogen supply pipeline, a mixed refrigerant suction tank, a mixed refrigerant compressor, a mixed refrigerant cooler, a mixed refrigerant throttle valve, a raw material gas hydrogen pipeline, a liquid hydrogen product pipeline, a nitrogen pipeline, a first hydrogen refrigerant pipeline, a first hydrogen expansion pipeline, a second hydrogen refrigerant pipeline, and a second hydrogen expansion pipeline.

[0025] The mixed refrigerant system includes a mixed refrigerant suction tank 16, a mixed refrigerant compressor 17, a mixed refrigerant cooler 18, a mixed refrigerant throttle valve 19, and a first mixed refrigerant circulation channel and a second mixed refrigerant circulation channel of the first heat exchanger 3, which are used to provide the cooling capacity of the mixed refrigerant to the first heat exchanger 3.

[0026] The mixed refrigerant intake tank 16, mixed refrigerant compressor 17, mixed refrigerant cooler 18, first mixed refrigerant circulation channel of first heat exchanger 3, mixed refrigerant throttle valve 19, and second mixed refrigerant circulation channel of first heat exchanger 3 are connected in sequence.

[0027] The nitrogen refrigeration pipeline includes a liquid nitrogen supply pipeline 15, a liquid nitrogen vaporization channel for the second heat exchanger 4, a nitrogen reheating channel for the first heat exchanger 3, and a nitrogen pipeline 22.

[0028] The liquid nitrogen supply pipeline 15 is sequentially connected to the liquid nitrogen vaporization channel of the second heat exchanger 4, the nitrogen reheating channel of the first heat exchanger 3, and the nitrogen pipeline 22, and is used to provide the cooling capacity of liquid nitrogen refrigerant to the second heat exchanger 4 and the first heat exchanger 3.

[0029] The circulating hydrogen refrigeration system includes a circulating hydrogen refrigerant compressor 1, a hydrogen cooler 2, a first turbine expander unit 11, a second turbine expander unit 12, a third turbine expander unit 14, a first hydrogen refrigerant pipeline 23, a first hydrogen expansion pipeline 24, a second hydrogen refrigerant pipeline 25, a second hydrogen expansion pipeline 26, an expansion hydrogen flow channel, and a hydrogen flash vapor flow channel.

[0030] The expansion hydrogen flow channels include the first expansion hydrogen flow channel of the first heat exchanger 3, the second expansion hydrogen flow channel of the second heat exchanger 4, the third expansion hydrogen flow channel of the third heat exchanger 5, the fourth expansion hydrogen flow channel of the fourth heat exchanger 6, and the fifth expansion hydrogen flow channel of the fifth heat exchanger 7.

[0031] The hydrogen flash vapor flow path includes a first expansion hydrogen flow path of the first heat exchanger 3, a second expansion hydrogen flow path of the second heat exchanger 4, a third expansion hydrogen flow path of the fourth heat exchanger 6, and a fourth expansion hydrogen flow path of the fifth heat exchanger 7.

[0032] The first heat exchanger 3 includes a first gaseous hydrogen flow channel, a second gaseous hydrogen flow channel, a nitrogen reheat flow channel, a first mixed refrigerant circulation flow channel, a second mixed refrigerant circulation flow channel, a first expanded hydrogen flow channel, and a first hydrogen flash vapor flow channel.

[0033] The second heat exchanger 4 includes a third gaseous hydrogen flow channel, a fourth gaseous hydrogen flow channel, a liquid nitrogen vaporization flow channel, a second expansion hydrogen flow channel, and a second hydrogen flash vapor flow channel.

[0034] The third heat exchanger 5 includes a fifth hydrogen flow channel, a sixth hydrogen flow channel, and a third expansion hydrogen flow channel.

[0035] The fourth heat exchanger 6 includes a first gas hydrogen flow channel, a fourth expansion hydrogen flow channel, and a third hydrogen flash vapor flow channel.

[0036] The fifth heat exchanger 7 includes an eighth gas hydrogen flow channel, a fifth expansion hydrogen flow channel, and a fourth hydrogen flash vapor flow channel.

[0037] The raw material gas hydrogen pipeline 20 merges with the circulating hydrogen pipeline after the hydrogen cooler 2 and enters the first heat exchanger 3. It is sequentially connected to the first gas hydrogen flow channel of the first heat exchanger 3, the first positive and negative hydrogen converter 8, the second gas hydrogen flow channel of the first heat exchanger 3, the third gas hydrogen flow channel of the second heat exchanger 4, the second positive and negative hydrogen converter 9, the fourth gas hydrogen flow channel of the second heat exchanger 4, the fifth gas hydrogen flow channel of the third heat exchanger 5, the third positive and negative hydrogen converter 10, the sixth gas hydrogen flow channel of the third heat exchanger 5, the seventh gas hydrogen flow channel of the fourth heat exchanger 6, the eighth gas hydrogen flow channel of the fifth heat exchanger 7, and the third turbine expander unit 14. After expansion by the third turbine expander unit 14, it is sequentially connected to the liquid hydrogen storage tank 13 and the liquid hydrogen product pipeline 21.

[0038] Furthermore, the top gas phase of the liquid hydrogen storage tank 13 is sequentially connected to the fourth hydrogen flash vapor channel of the fifth heat exchanger 7, the third hydrogen flash vapor channel of the fourth heat exchanger 6, the second hydrogen flash vapor channel of the second heat exchanger 4, the first hydrogen flash vapor channel of the first heat exchanger 3, and the circulating hydrogen refrigerant compressor 1.

[0039] Furthermore, a first hydrogen refrigerant pipeline 23 is separated between the sixth hydrogen flow channel of the third heat exchanger 5 and the seventh hydrogen flow channel of the fourth heat exchanger 6, and is sequentially connected to the first turbine expander unit 11, the first hydrogen expansion pipeline 24, and the fourth expansion hydrogen flow channel of the fourth heat exchanger 6.

[0040] Furthermore, a second hydrogen refrigerant pipeline 25 is separated between the seventh hydrogen flow channel of the fourth heat exchanger 6 and the eighth hydrogen flow channel of the fifth heat exchanger 7, and is sequentially connected to the second turbine expander unit 12, the second hydrogen expansion pipeline 26, and the fifth expansion hydrogen flow channel of the fifth heat exchanger 7.

[0041] Furthermore, the fifth expansion hydrogen flow channel of the fifth heat exchanger 7, the fourth expansion hydrogen flow channel of the fourth heat exchanger 6, the third expansion hydrogen flow channel of the third heat exchanger 5, the second expansion hydrogen flow channel of the second heat exchanger 4, the first expansion hydrogen flow channel of the first heat exchanger 3, and the circulating hydrogen refrigerant compressor 1 are connected in sequence.

[0042] Furthermore, the mixed refrigerant consists of nitrogen, methane, ethylene, and propane.

[0043] Furthermore, the hydrogen gas is pre-cooled to below -150°C using a mixed refrigerant through the first heat exchanger 3.

[0044] Furthermore, liquid nitrogen is used to pre-cool hydrogen to below -190°C through the first heat exchanger 3 and the second heat exchanger 4.

[0045] Furthermore, the temperature and pressure of the raw material hydrogen gas are the same as those of the circulating hydrogen pipeline after the hydrogen cooler 2.

[0046] Furthermore, the hydrogen volume content of the raw material gas is 99.999%.

[0047] Furthermore, the hydrogen cooler 2 and the mixed refrigerant cooler 18 are water-cooled.

[0048] Furthermore, the third turbine expander unit 14 is a hydraulic turbine expander unit.

[0049] A method for liquefying hydrogen using a mixed refrigerant and precooling with liquid nitrogen, comprising the following steps;

[0050] The hydrogen used for liquefaction has a pressure of not less than 1.4 MPa and a purity of 99.999% (volume fraction).

[0051] In the first step, the raw material hydrogen gas is mixed with the circulating hydrogen gas and then enters the first heat exchanger 3. The hydrogen gas is cooled to -150°C by using the cold energy of the mixed refrigerant, nitrogen gas, the first expansion hydrogen gas flow channel, and the first hydrogen flash vapor flow channel.

[0052] In the second step, the hydrogen passes through the first positive and secondary hydrogen converter 8, where a portion of the positive hydrogen is converted into secondary hydrogen. This conversion process is an exothermic reaction, and the temperature of the hydrogen increases.

[0053] In the third step, hydrogen gas re-enters the first heat exchanger 3 to replenish cooling energy and lower the temperature to -150℃.

[0054] In the fourth step, hydrogen enters the second heat exchanger 4, where it is cooled to -190°C by utilizing the cold energy from liquid nitrogen vaporization, the second expansion hydrogen flow channel, and the second hydrogen flash vapor flow channel.

[0055] In the fifth step, the hydrogen passes through the second positive and negative hydrogen converter 9, where most of the positive hydrogen is converted into negative hydrogen. This conversion process is an exothermic reaction, and the temperature of the hydrogen increases.

[0056] In the sixth step, hydrogen gas re-enters the second heat exchanger 4 to replenish cooling energy and lower the temperature to -190℃.

[0057] In the seventh step, hydrogen enters the third heat exchanger 5, where the cold energy of the third expansion hydrogen flow channel is used to cool the hydrogen to -200 to -220°C.

[0058] In the eighth step, the hydrogen passes through the third positive and negative hydrogen converter 10, where most of the positive hydrogen is converted into negative hydrogen. At this point, the negative hydrogen content is ≥95%. This conversion process is an exothermic reaction, and the temperature of the hydrogen increases.

[0059] In the ninth step, hydrogen gas re-enters the third heat exchanger 5 to replenish cooling energy and lower the temperature to -200 to -220°C.

[0060] In the tenth step, the hydrogen gas is separated into two streams. One stream enters the fourth heat exchanger 6, where it is cooled to -228 to -248°C using the cooling energy of the fourth expansion hydrogen flow channel and the third hydrogen flash vapor flow channel. The other stream of hydrogen gas enters the first turbine expander unit 11, expands and cools down, and then merges into the fourth expansion hydrogen flow channel to provide cooling for the fourth heat exchanger 6.

[0061] In the eleventh step, the hydrogen gas, cooled to -228 to -248°C, is separated into two streams. One stream enters the fifth heat exchanger 7, where it is liquefied and subcooled to -253°C using the cold energy of the fifth expansion hydrogen flow channel and the fourth hydrogen flash vapor flow channel. The other stream of hydrogen gas enters the second turbine expander unit 12, expands and cools down, and then merges into the fifth expansion hydrogen flow channel to provide cooling for the fifth heat exchanger 7.

[0062] In the twelfth step, the supercooled liquid hydrogen enters the third turbine expander unit 14, expands to 115-120 kPa, and then enters the liquid hydrogen storage tank 13. The liquid hydrogen is then transported to the next process through the liquid hydrogen pipeline at the bottom of the liquid hydrogen storage tank 13.

[0063] Mixed refrigerant refrigeration cycle: After being pressurized by the mixed refrigerant compressor and cooled by the mixed refrigerant cooler, the mixed refrigerant enters the first heat exchanger to liquefy. After being throttled and subcooled by the mixed refrigerant throttling valve, it returns to the first heat exchanger to provide cooling. The vaporized and reheated mixed refrigerant enters the mixed refrigerant suction tank, and after separation, it enters the mixed refrigerant compressor for the next cycle.

[0064] Nitrogen cooling: Liquid nitrogen pre-cools hydrogen gas through the second heat exchanger and the first heat exchanger.

[0065] As described above, the present invention can be implemented well.

[0066] All features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A hydrogen liquefaction device, characterized in that, It includes a mixed refrigerant suction tank (16), a mixed refrigerant compressor (17), a mixed refrigerant cooler (18), and a first heat exchanger (3) connected in sequence, and also includes a mixed refrigerant throttle valve (19) connected to the first heat exchanger (3).

2. The hydrogen liquefaction device according to claim 1, characterized in that, The first heat exchanger (3) includes a first mixed refrigerant circulation channel, a second mixed refrigerant circulation channel, a mixed refrigerant cooler (18), a first mixed refrigerant circulation channel, a mixed refrigerant throttle valve (19), a second mixed refrigerant circulation channel, and a mixed refrigerant suction tank (16) connected in sequence.

3. The hydrogen liquefaction device according to claim 2, characterized in that, Includes a circulating hydrogen refrigerant compressor (1), a hydrogen cooler (2), a second heat exchanger (4), a third heat exchanger (5), a fourth heat exchanger (6), a fifth heat exchanger (7), a first and second intermediate hydrogen converter (8), a second and third intermediate hydrogen converter (9), a third and second intermediate hydrogen converter (10), a liquid hydrogen storage tank (13), a third turbine expander unit (14), a raw material gas hydrogen pipeline (20), a liquid hydrogen product pipeline (21), a circulating hydrogen refrigerant compressor (1), a hydrogen cooler (2), a first heat exchanger (3), a second heat exchanger (4 ...5), a third turbine expander unit (6), a third turbine expander unit (7), a raw material gas hydrogen pipeline (20), a liquid hydrogen product pipeline (21), a circulating hydrogen refrigerant compressor (1), a hydrogen cooler (2), a first heat exchanger (3), a third turbine expander unit (4), a third turbine expander unit (5), a third turbine expander unit (6), a third turbine expander unit (7), a raw material gas hydrogen pipeline (20), a circulating hydrogen refrigerant compressor (1), a hydrogen cooler (2), a first heat exchanger (3), a third turbine expander unit (4), a third turbine expander unit (5), a third turbine expander unit (6), a third turbine expander unit (7), a raw material gas hydrogen pipeline (21), a first hydrogen product hydrogen pipeline (2), a third turbine expander unit (2), a third turbine expander unit (2), a third turbine expander unit (2), a third turbine expander unit (2), a third turbine expander unit (2), a third turbine expander unit (2), a third turbine expander unit (2), a third turbine expander unit (2), a third turbine expander unit (2), a third turbine expander unit (2), a third turbine expand Heat exchanger (4), third heat exchanger (5), fourth heat exchanger (6), fifth heat exchanger (7), third turbine expander (14), liquid hydrogen storage tank (13), and liquid hydrogen product pipeline (21) are connected in sequence. The connecting pipeline between hydrogen cooler (2) and first heat exchanger (3) is connected to raw material gas hydrogen pipeline (20). First heat exchanger (3) is connected to first neutral hydrogen converter (8). Second heat exchanger (4) is connected to second neutral hydrogen converter (9). Third heat exchanger (5) is connected to third neutral hydrogen converter (10).

4. The hydrogen liquefaction device according to claim 3, characterized in that, The first heat exchanger (3) includes a first hydrogen flow channel and a second hydrogen flow channel; the second heat exchanger (4) includes a third hydrogen flow channel and a fourth hydrogen flow channel; the third heat exchanger (5) includes a fifth hydrogen flow channel and a sixth hydrogen flow channel; the fourth heat exchanger (6) includes a seventh hydrogen flow channel; and the fifth heat exchanger (7) includes an eighth hydrogen flow channel. The circulating hydrogen refrigerant compressor (1), the hydrogen cooler (2), the first hydrogen flow channel, the first positive and negative hydrogen converter (8), the second hydrogen flow channel, the third hydrogen flow channel, the second positive and negative hydrogen converter (9), the fourth hydrogen flow channel, the fifth hydrogen flow channel, the third positive and negative hydrogen converter (10), the sixth hydrogen flow channel, the seventh hydrogen flow channel, the eighth hydrogen flow channel, and the third turbine expander (14) are connected in sequence.

5. A hydrogen liquefaction device according to claim 4, characterized in that, The fifth heat exchanger (7) includes a fourth hydrogen flash vapor channel, the fourth heat exchanger (6) includes a third hydrogen flash vapor channel, the second heat exchanger (4) includes a second hydrogen flash vapor channel, the first heat exchanger (3) includes a first hydrogen flash vapor channel, and the gas phase of the liquid hydrogen storage tank (13), the fourth hydrogen flash vapor channel, the third hydrogen flash vapor channel, the second hydrogen flash vapor channel, the first hydrogen flash vapor channel, and the circulating hydrogen refrigerant compressor (1) are connected in sequence.

6. A hydrogen liquefaction device according to claim 5, characterized in that, The first turbine expander (11), the first hydrogen refrigerant pipeline (23), and the first hydrogen expansion pipeline (24) are included. The fourth heat exchanger (6) includes the fourth expansion hydrogen flow channel, the connecting pipeline between the sixth and seventh hydrogen flow channels, the first hydrogen refrigerant pipeline (23), the first turbine expander (11), the first hydrogen expansion pipeline (24), and the fourth expansion hydrogen flow channel are connected in sequence.

7. A hydrogen liquefaction device according to claim 6, characterized in that, The system includes a second turbine expander (12), a second hydrogen refrigerant pipeline (25), a second hydrogen expansion pipeline (26), and a fifth heat exchanger (7) including a fifth expansion hydrogen flow channel, a connecting pipeline between the seventh and eighth hydrogen flow channels, the second hydrogen refrigerant pipeline (25), the second turbine expander (12), the second hydrogen expansion pipeline (26), and the fifth expansion hydrogen flow channel connected in sequence.

8. A hydrogen liquefaction device according to claim 6, characterized in that, The fourth heat exchanger (6) includes a fourth expansion hydrogen flow channel, the third heat exchanger (5) includes a third expansion hydrogen flow channel, the second heat exchanger (4) includes a second expansion hydrogen flow channel, the first heat exchanger (3) includes a first expansion hydrogen flow channel, and the fifth expansion hydrogen flow channel, the fourth expansion hydrogen flow channel, the third expansion hydrogen flow channel, the second expansion hydrogen flow channel, the first expansion hydrogen flow channel, and the circulating hydrogen refrigerant compressor 1 are connected in sequence.

9. A hydrogen liquefaction device according to any one of claims 2 to 8, characterized in that, The system includes a liquid nitrogen supply pipeline (15) and a nitrogen pipeline (22). The second heat exchanger (4) includes a liquid nitrogen vaporization channel, and the first heat exchanger (3) includes a nitrogen reheating channel. The liquid nitrogen supply pipeline (15), the liquid nitrogen vaporization channel, the nitrogen reheating channel, and the nitrogen pipeline (22) are connected in sequence.

10. A method for liquefying hydrogen, characterized in that, Hydrogen liquefaction is performed using a hydrogen liquefaction device according to any one of claims 2 to 9. The mixed refrigerant passes sequentially through a mixed refrigerant suction tank (16), a mixed refrigerant compressor (17), a mixed refrigerant cooler (18), a first mixed refrigerant circulation channel, a mixed refrigerant throttle valve (19), a second mixed refrigerant circulation channel, and a mixed refrigerant suction tank (16), thereby providing the cooling capacity of the mixed refrigerant to the first heat exchanger (3).

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