Low-temperature supercritical hydrogen storage system using two-stage parallel mixed refrigerant refrigeration

Abstract

The application provides a low-temperature supercritical hydrogen storage system using a two-stage parallel mixed refrigerant for refrigeration, comprising a hydrogen compression cooling system, a pre-cooling mixed refrigerant compression cooling system, a deep cooling mixed refrigerant compression cooling system, a first-stage heat exchange system, a second-stage heat exchange system, a third-stage heat exchange system, a fourth-stage heat exchange system, a fifth-stage heat exchange system and a sixth-stage heat exchange system. The hydrogen passes through the hydrogen compression cooling system, the first-stage heat exchange system, the second-stage heat exchange system, the third-stage heat exchange system, the fourth-stage heat exchange system, the fifth-stage heat exchange system and the sixth-stage heat exchange system in sequence and is converted into low-temperature supercritical hydrogen and stored in a hydrogen storage tank. The pre-cooling mixed refrigerant is used for pre-cooling the hydrogen and the deep cooling mixed refrigerant, the cooling of the hydrogen by the mixed refrigerant can be fully utilized, the production cost is reduced, the cooling effect is improved, and the circulating performance of the mixed refrigerant in the system is good.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of hydrogen storage, in particular to a low-temperature supercritical hydrogen storage system using a two-stage parallel mixed refrigerant refrigeration method. BACKGROUND

[0002] Hydrogen energy is a clean, efficient and renewable green energy, which has the characteristics of high combustion heat value, large energy density, wide sources, various utilization forms and energy storage, and is conducive to improving the energy structure, promoting the energy revolution and realizing the development goal of “carbon neutralization and carbon peak”.

[0003] Hydrogen production, hydrogen storage, hydrogen transportation and hydrogen addition are a complete system engineering. Hydrogen storage is an important part of hydrogen application. The high-pressure gaseous storage method in the prior art is a widely used method at present. The hydrogen is stored in a high-pressure state. Although the high-pressure gaseous storage method is low in cost, simple and easy to implement, it has low storage density, needs thick and heavy pressure-resistant containers and is prone to leakage. The low-temperature liquid hydrogen storage method liquefies hydrogen into liquid hydrogen through compression and cooling. Although the low-temperature liquid hydrogen storage method is good in safety and excellent in cycle performance, the hydrogen liquefaction needs to reach a low temperature of-253 DEG C, and the liquidization process has high energy consumption and cost, large technical difficulty and large evaporation loss in long-term storage. Compared with high-pressure gaseous hydrogen, the low-temperature supercritical hydrogen has larger storage density and is not affected by temperature rise during refueling, which is conducive to improving the hydrogen energy utilization efficiency. In addition, the supercritical hydrogen does not need to reach the low temperature of-253 DEG C of liquid hydrogen, so that energy can be saved, and problems such as liquid hydrogen evaporation are avoided.

[0004] Chinese patent CN115854651A discloses a hydrogen liquefaction method and device using a refrigerator for precooling, and specifically discloses that the hydrogen liquefaction device comprises a high-pressure hydrogen source, a pressure reducing valve, a first ortho-para hydrogen conversion reactor, a second ortho-para hydrogen conversion reactor, a first throttling valve, a third ortho-para hydrogen conversion reactor, a second throttling valve and a liquid hydrogen storage tank which are connected in sequence. The first ortho-para hydrogen conversion reactor, the second ortho-para hydrogen conversion reactor and the third ortho-para hydrogen conversion reactor are respectively connected with a first refrigerator, a second refrigerator and a third refrigerator. The first refrigerator, the second refrigerator and the third refrigerator each use one or more refrigerators. The device has a complex process, and the stability and reliability need to be further verified.

[0005] Chinese patent CN115615138A discloses a hydrogen liquefaction system based on nitrogen and neon circulation expansion refrigeration, and specifically discloses: the hydrogen liquefaction system comprises a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a fifth heat exchanger, a supercooler, a first nitrogen turboexpander, a second nitrogen turboexpander, a first neon turboexpander, a second neon turboexpander, a hydrogen turboexpander, a hydrogen cryogenic purifier, an ejector, and a liquid hydrogen storage tank. The comprehensive energy consumption of the invention is 10 KWh / kg of liquid hydrogen, which is relatively high, and the process is complex, and the stability and reliability need to be further verified.

[0006] Chinese patent CN115682628A discloses a hydrogen liquefaction system and process based on mixed refrigerant precooling, and specifically discloses: the hydrogen liquefaction system comprises a hydrogen liquefaction pipeline, a precooling cold box module, a normal and para hydrogen conversion module, a supercooling cold box module, a liquid hydrogen storage module, a mixed refrigerant compression module, and a hydrogen refrigerant compression module; wherein: the hydrogen liquefaction pipeline connects the precooling module, the normal and para hydrogen conversion module, the supercooling module, and the liquid hydrogen storage module in sequence; the mixed refrigerant compression module is connected with the precooling cold box module and used to provide mixed refrigerant to the precooling cold box module; and the hydrogen refrigerant compression module is connected with the supercooling cold box module and used to provide hydrogen refrigerant to the supercooling cold box module. The hydrogen liquefaction system uses a mixed refrigerant cycle in the precooling stage and a hydrogen refrigeration cycle in the supercooling stage, the flow rate and pressure of the refrigerant are optimized, the energy consumption is effectively reduced, the heat exchange characteristics of the liquefaction process are improved, and the heat exchange efficiency is improved, but the process is complex, the cost is high, and the stability and reliability need to be further verified.

[0007] Chinese patent CN209705707U discloses a hydrogenation system based on deep cooling high pressure hydrogen storage, and specifically discloses: the hydrogenation system comprises a liquid hydrogen storage tank, a liquid hydrogen booster pump, a vaporizer, a high-pressure gas hydrogen bottle, a mixer, a hydrogenation machine, and a central controller; the liquid hydrogen storage tank is connected with the inlet of the liquid hydrogen booster pump through a pipeline; the outlet of the vaporizer is connected with the inlet of the high-pressure gas hydrogen bottle through a pipeline; the outlet of the high-pressure gas hydrogen bottle is connected with one inlet of the mixer through a pipeline; the outlet of the mixer is connected with the inlet of the hydrogenation machine through a pipeline; the hydrogenation system further comprises a deep cooling high pressure hydrogen storage bottle for forming and storing supercritical hydrogen; the outlet of the liquid hydrogen booster pump is connected with the inlet of the deep cooling high pressure hydrogen storage bottle through a pipeline; the outlet of the deep cooling high pressure hydrogen storage bottle is connected with the other inlet of the mixer through a pipeline; and the outlet of the deep cooling high pressure hydrogen storage bottle is also connected with the inlet of the vaporizer through a pipeline. The process is complex, and the stability and reliability need to be further verified.

[0008] Chinese patent CN113446815A discloses a mixed refrigeration hydrogen liquefaction equipment and its use method, and specifically discloses that the hydrogen liquefaction equipment comprises a normal-pressure pre-cooling cold box II, a vacuum deep cooling cold box III, a hydrogen refrigeration circulating compressor set, a nitrogen circulating refrigeration unit, a mixed refrigerant circulating refrigeration unit, a mixed refrigerant process and a nitrogen circulating refrigeration process are used as main cold quantity sources in a pre-cooling section, a refrigerant refrigeration cycle is a main cold quantity source in a 303K to 113K temperature zone, a liquid nitrogen refrigeration cycle is a main cold quantity source in a 130K to 80K temperature zone, a hydrogen refrigeration cycle provides cold quantity in a 80K to 20K temperature zone, and most of BOG generated in a storage part is recovered through an ejector. The product is liquid hydrogen, there is evaporation loss, the liquefaction cost is high, the process is complex, and the stability and reliability need to be further verified. SUMMARY

[0009] The present application is carried out in order to solve the above problems, and aims at providing a low-temperature supercritical hydrogen storage system using a two-stage parallel mixed refrigerant refrigeration.

[0010] The application provides a low-temperature supercritical hydrogen storage system using two-stage parallel mixed refrigerant refrigeration, which has the following characteristics: a hydrogen compression cooling system for compressing and cooling hydrogen; a pre-cooling mixed refrigerant compression cooling system for compressing and cooling pre-cooling mixed refrigerant; a deep cooling mixed refrigerant compression cooling system for compressing and cooling deep cooling mixed refrigerant; a first heat exchange system for dividing the cooled pre-cooling mixed refrigerant from the pre-cooling mixed refrigerant compression cooling system into gas-liquid two-phase, throttling and cooling the liquid-phase pre-cooling mixed refrigerant, and using the throttled and cooled pre-cooling mixed refrigerant to cool the gas-liquid two-phase pre-cooling mixed refrigerant, hydrogen from the hydrogen compression cooling system, and deep cooling mixed refrigerant from the deep cooling mixed refrigerant compression cooling system; a second heat exchange system for dividing the cooled pre-cooling mixed refrigerant from the first heat exchange system into gas-liquid two-phase, throttling and cooling the liquid-phase pre-cooling mixed refrigerant, and using the throttled and cooled pre-cooling mixed refrigerant to cool the gas-liquid two-phase pre-cooling mixed refrigerant, hydrogen from the first heat exchange system, and deep cooling mixed refrigerant, and returning the pre-cooling mixed refrigerant after absorbing heat to the first heat exchange system to cool hydrogen, pre-cooling mixed refrigerant, and deep cooling mixed refrigerant; a third heat exchange system for throttling and cooling the cooled pre-cooling mixed refrigerant from the second heat exchange system, and using the throttled and cooled pre-cooling mixed refrigerant to cool hydrogen, deep cooling mixed refrigerant, and pre-cooling mixed refrigerant from the second heat exchange system, and returning the pre-cooling mixed refrigerant after absorbing heat to the second heat exchange system to cool hydrogen, pre-cooling mixed refrigerant, and deep cooling mixed refrigerant; a fourth heat exchange system for dividing the cooled deep cooling mixed refrigerant from the third heat exchange system into two parts, expanding and cooling one part of the deep cooling mixed refrigerant, and using the expanded and cooled deep cooling mixed refrigerant to cool the other part of the deep cooling mixed refrigerant and hydrogen from the third heat exchange system, and returning the part of the deep cooling mixed refrigerant after absorbing heat to the third heat exchange system to cool hydrogen, pre-cooling mixed refrigerant, and deep cooling mixed refrigerant; a fifth heat exchange system for dividing the cooled deep cooling mixed refrigerant from the fourth heat exchange system into two parts, expanding and cooling one part of the deep cooling mixed refrigerant, and using the expanded and cooled deep cooling mixed refrigerant to cool the other part of the deep cooling mixed refrigerant and hydrogen from the fourth heat exchange system, and returning the part of the deep cooling mixed refrigerant after absorbing heat to the fourth heat exchange system to cool hydrogen and deep cooling mixed refrigerant; a sixth heat exchange system for expanding and cooling the cooled deep cooling mixed refrigerant from the fifth heat exchange system, and using the expanded and cooled deep cooling mixed refrigerant to cool hydrogen from the fifth heat exchange system to obtain low-temperature supercritical hydrogen; and a hydrogen storage tank for storing the low-temperature supercritical hydrogen from the sixth heat exchange system.The hydrogen passes through the hydrogen compression cooling system, the first-stage heat exchange system, the second-stage heat exchange system, the third-stage heat exchange system, the fourth-stage heat exchange system, the fifth-stage heat exchange system and the sixth-stage heat exchange system in sequence and finally enters the hydrogen storage tank.

[0011] In the low-temperature supercritical hydrogen storage system provided by the application, the hydrogen compression cooling system comprises a first hydrogen compressor, a first hydrogen water cooler, a second hydrogen compressor, a second hydrogen water cooler, a third hydrogen compressor, a third hydrogen water cooler, a fourth hydrogen compressor, a fourth hydrogen water cooler, a fifth hydrogen compressor and a fifth hydrogen water cooler, the hydrogen passes through the above-mentioned devices in sequence in the hydrogen compression cooling system, the pressure of the hydrogen compressed and cooled by the hydrogen compression cooling system is greater than the standard critical pressure, the first hydrogen compressor, the second hydrogen compressor, the third hydrogen compressor, the fourth hydrogen compressor and the fifth hydrogen compressor are used for compressing the hydrogen, and the first hydrogen water cooler, the second hydrogen water cooler, the third hydrogen water cooler, the fourth hydrogen water cooler and the fifth hydrogen water cooler are used for cooling the hydrogen compressed each time.

[0012] In the low-temperature supercritical hydrogen storage system provided by the application, the pre-cooled mixed refrigerant compression cooling system comprises a first pre-cooled mixed refrigerant compressor, a first pre-cooled mixed refrigerant water cooler, a first gas-liquid separator, a second pre-cooled mixed refrigerant compressor, a second pre-cooled mixed refrigerant water cooler, a pre-cooled mixed refrigerant pump and a first mixer, the first pre-cooled mixed refrigerant compressor is used for compressing the pre-cooled mixed refrigerant, the first pre-cooled mixed refrigerant water cooler is used for cooling the pre-cooled mixed refrigerant compressed by the first pre-cooled mixed refrigerant compressor, the first gas-liquid separator is used for separating the pre-cooled mixed refrigerant cooled by the first pre-cooled mixed refrigerant water cooler into gas and liquid phases, the second pre-cooled mixed refrigerant compressor is used for compressing the gas-phase pre-cooled mixed refrigerant, the second pre-cooled mixed refrigerant water cooler is used for cooling the pre-cooled mixed refrigerant compressed by the second pre-cooled mixed refrigerant compressor, the pre-cooled mixed refrigerant pump is used for compressing the liquid-phase pre-cooled mixed refrigerant, and the first mixer is used for mixing the pre-cooled mixed refrigerant cooled by the second pre-cooled mixed refrigerant water cooler and the pre-cooled mixed refrigerant compressed by the pre-cooled mixed refrigerant pump.

[0013] In the low-temperature supercritical hydrogen storage system using two-stage parallel mixed refrigerant refrigeration provided by the application, the deep cooling mixed refrigerant compression cooling system can further comprise a first deep cooling mixed refrigerant compressor, a first deep cooling mixed refrigerant water cooler, a second deep cooling mixed refrigerant compressor, a second deep cooling mixed refrigerant water cooler, a third deep cooling mixed refrigerant compressor, and a third deep cooling mixed refrigerant water cooler, the deep cooling mixed refrigerant sequentially passes through the above devices in order in the deep cooling mixed refrigerant compression cooling system, the first deep cooling mixed refrigerant compressor, the second deep cooling mixed refrigerant compressor, and the third deep cooling mixed refrigerant compressor are used for compressing the deep cooling mixed refrigerant, and the first deep cooling mixed refrigerant water cooler, the second deep cooling mixed refrigerant water cooler, and the third deep cooling mixed refrigerant water cooler are used for cooling the deep cooling mixed refrigerant after each compression.

[0014] In the low-temperature supercritical hydrogen storage system using two-stage parallel mixed refrigerant refrigeration provided by the application, the primary heat exchange system can further comprise a second gas-liquid separator, a first throttling valve, a second mixer, and a first heat exchanger, the second gas-liquid separator is used for separating the pre-cooling mixed refrigerant compressed and cooled by the pre-cooling mixed refrigerant compression cooling system into gas-liquid two phases and entering the first heat exchanger, the first throttling valve is used for throttling and cooling the liquid-phase pre-cooling mixed refrigerant from the first heat exchanger, the second mixer is used for receiving the pre-cooling mixed refrigerant after being throttled and cooled by the first throttling valve, and the first heat exchanger is used for cooling the pre-cooling mixed refrigerant from the second gas-liquid separator, the hydrogen compressed and cooled in the hydrogen compression cooling system, and the deep cooling mixed refrigerant compressed and cooled in the deep cooling mixed refrigerant compression cooling system by using the pre-cooling mixed refrigerant after being throttled and cooled by the first throttling valve.

[0015] In the low-temperature supercritical hydrogen storage system using two-stage parallel mixed refrigerant refrigeration provided by the application, the secondary heat exchange system can further comprise a third gas-liquid separator, a second throttling valve, a third mixer, and a second heat exchanger, the third gas-liquid separator is used for separating the pre-cooling mixed refrigerant cooled by the first heat exchanger into gas-liquid two phases and entering the second heat exchanger, the second throttling valve is used for throttling and cooling the liquid-phase pre-cooling mixed refrigerant from the second heat exchanger, the third mixer is used for receiving the pre-cooling mixed refrigerant after being throttled and cooled by the second throttling valve, and the second heat exchanger is used for cooling the pre-cooling mixed refrigerant from the third gas-liquid separator, and the hydrogen and the deep cooling mixed refrigerant cooled in the first heat exchanger by using the pre-cooling mixed refrigerant after being throttled and cooled by the second throttling valve.

[0016] In the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration provided by the application, the third heat exchange system can further comprise a third throttling valve and a third heat exchanger, the third throttling valve is used for throttling and cooling the pre-cooling mixed refrigerant from the third heat exchanger, and the third heat exchanger is used for cooling the hydrogen cooled in the second heat exchanger, the pre-cooling mixed refrigerant and the deep cooling mixed refrigerant by using the pre-cooling mixed refrigerant throttled and cooled by the third throttling valve.

[0017] In the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration provided by the application, the third heat exchange system can further comprise a third throttling valve and a third heat exchanger, the third throttling valve is used for throttling and cooling the pre-cooling mixed refrigerant from the third heat exchanger, and the third heat exchanger is used for cooling the hydrogen cooled in the second heat exchanger, the pre-cooling mixed refrigerant and the deep cooling mixed refrigerant by using the pre-cooling mixed refrigerant throttled and cooled by the third throttling valve.

[0018] In the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration provided by the application, the third heat exchange system can further comprise a third throttling valve and a third heat exchanger, the third throttling valve is used for throttling and cooling the pre-cooling mixed refrigerant from the third heat exchanger, and the third heat exchanger is used for cooling the hydrogen cooled in the second heat exchanger, the pre-cooling mixed refrigerant and the deep cooling mixed refrigerant by using the pre-cooling mixed refrigerant throttled and cooled by the third throttling valve.

[0019] In the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration provided by the application, the third heat exchange system can further comprise a third throttling valve and a third heat exchanger, the third throttling valve is used for throttling and cooling the pre-cooling mixed refrigerant from the third heat exchanger, and the third heat exchanger is used for cooling the hydrogen cooled in the second heat exchanger, the pre-cooling mixed refrigerant and the deep cooling mixed refrigerant by using the pre-cooling mixed refrigerant throttled and cooled by the third throttling valve.

[0020] In the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration provided by the application, the six-stage heat exchange system comprises a third expander and a sixth heat exchanger, the third expander is used for expanding and cooling the cryogenic mixed refrigerant cooled in the fifth heat exchanger, and the sixth heat exchanger is used for cooling the hydrogen cooled in the fifth heat exchanger by using the cryogenic mixed refrigerant cooled by the third expander, so as to obtain the low-temperature supercritical hydrogen.

[0021] In the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration provided by the application, the six-stage heat exchange system comprises a third expander and a sixth heat exchanger, the third expander is used for expanding and cooling the cryogenic mixed refrigerant cooled in the fifth heat exchanger, and the sixth heat exchanger is used for cooling the hydrogen cooled in the fifth heat exchanger by using the cryogenic mixed refrigerant cooled by the third expander, so as to obtain the low-temperature supercritical hydrogen.

[0022] In the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration provided by the application, the six-stage heat exchange system comprises a third expander and a sixth heat exchanger, the third expander is used for expanding and cooling the cryogenic mixed refrigerant cooled in the fifth heat exchanger, and the sixth heat exchanger is used for cooling the hydrogen cooled in the fifth heat exchanger by using the cryogenic mixed refrigerant cooled by the third expander, so as to obtain the low-temperature supercritical hydrogen.

[0023] Effects of the application

[0024] According to the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration provided by the application, because the hydrogen gas compression cooling system, the pre-cooling mixed refrigerant compression cooling system, the cryogenic mixed refrigerant compression cooling system, the first-stage heat exchange system, the second-stage heat exchange system, the third-stage heat exchange system, the fourth-stage heat exchange system, the fifth-stage heat exchange system and the sixth-stage heat exchange system are included, the hydrogen gas is converted into the low-temperature supercritical hydrogen, the low-temperature supercritical hydrogen has the characteristics of high density and difficult evaporation loss, so that the low-temperature supercritical hydrogen storage system has the characteristics of high storage density, good safety, no need of thick and heavy pressure-resistant container and difficult hydrogen leakage, and the hydrogen gas and the cryogenic mixed refrigerant are pre-cooled by using the pre-cooling mixed refrigerant, the cooling of the hydrogen gas by the mixed refrigerant can be fully utilized, the production cost is reduced, the cooling effect is improved, and the mixed refrigerant has good circulation performance in the system.

[0025] In summary, the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration provided by the present application has the characteristics of low cost, simplicity, high storage density, no need for thick and heavy pressure-resistant containers, less evaporation loss and leakage, good safety, and excellent cycle performance. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration in the embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the present application is specifically described below in conjunction with the drawings.

[0028] EMBODIMENT

[0029] Figure 1 is a schematic diagram of the low-temperature supercritical hydrogen storage system using the dual-stage parallel mixed refrigerant refrigeration.

[0030] As shown in Figure 1 The present embodiment provides a low-temperature supercritical hydrogen storage system using dual-stage parallel mixed refrigerant refrigeration, which comprises a hydrogen compression cooling system, a pre-cooling mixed refrigerant compression cooling system, a deep cooling mixed refrigerant compression cooling system, a first heat exchange system, a second heat exchange system, a third heat exchange system, a fourth heat exchange system, a fifth heat exchange system, a sixth heat exchange system, and a hydrogen storage tank. Each part is specifically described below.

[0031] The hydrogen compression cooling system is used for compressing and cooling hydrogen, and comprises a first hydrogen compressor C-101, a first hydrogen water cooler WC-101, a second hydrogen compressor C-102, a second hydrogen water cooler WC-102, a third hydrogen compressor C-103, a third hydrogen water cooler WC-103, a fourth hydrogen compressor C-104, a fourth hydrogen water cooler WC-104, a fifth hydrogen compressor C-105, and a fifth hydrogen water cooler WC-105 connected in sequence by pipelines. In operation, hydrogen passes through the above devices in the above order in the hydrogen compression cooling system. The first hydrogen compressor C-101, the second hydrogen compressor C-102, the third hydrogen compressor C-103, the fourth hydrogen compressor C-104, and the fifth hydrogen compressor C-105 are used for compressing hydrogen, and the first hydrogen water cooler WC-101, the second hydrogen water cooler WC-102, the third hydrogen water cooler WC-103, the fourth hydrogen water cooler WC-104, and the fifth hydrogen water cooler WC-105 are used for cooling hydrogen after each compression. The pressure of hydrogen after compression and cooling is greater than the standard critical pressure of hydrogen.

[0032] The pre-cooling mixed refrigerant compression cooling system for compressing and cooling the pre-cooling mixed refrigerant comprises a first pre-cooling mixed refrigerant compressor C-201, a first pre-cooling mixed refrigerant water cooler WC-201, a first gas-liquid separator V1, a second pre-cooling mixed refrigerant compressor C-202, a second pre-cooling mixed refrigerant water cooler WC-202, a pre-cooling mixed refrigerant pump P, and a first mixer MIX-1. The first pre-cooling mixed refrigerant compressor C-201 is used to compress the pre-cooling mixed refrigerant, and the first pre-cooling mixed refrigerant water cooler WC-201 is used to cool the pre-cooling mixed refrigerant compressed by the first pre-cooling mixed refrigerant compressor C-201. The first gas-liquid separator V1 is used to separate the pre-cooling mixed refrigerant cooled by the first pre-cooling mixed refrigerant water cooler WC-201 into gas and liquid phases, the gaseous pre-cooling mixed refrigerant enters the second pre-cooling mixed refrigerant compressor C-202, and the liquid pre-cooling mixed refrigerant enters the pre-cooling mixed refrigerant pump P. The second pre-cooling mixed refrigerant compressor C-202 is used to compress the gaseous pre-cooling mixed refrigerant, and the second pre-cooling mixed refrigerant water cooler WC-202 is used to cool the pre-cooling mixed refrigerant compressed by the second pre-cooling mixed refrigerant compressor C-202. The pre-cooling mixed refrigerant pump P is used to compress the liquid pre-cooling mixed refrigerant. The first mixer MIX-1 is used to mix the pre-cooling mixed refrigerant cooled by the second pre-cooling mixed refrigerant water cooler WC-202 and the pre-cooling mixed refrigerant compressed by the pre-cooling mixed refrigerant pump P.

[0033] When the pre-cooling mixed refrigerant passes through the pre-cooling mixed refrigerant compression cooling system, the pre-cooling mixed refrigerant is first compressed by the first pre-cooling mixed refrigerant compressor C-201, then cooled by the first pre-cooling mixed refrigerant water cooler WC-201, and the cooled pre-cooling mixed refrigerant enters the first gas-liquid separator V1 to be separated into gas and liquid phases. The gaseous pre-cooling mixed refrigerant is compressed and cooled by the second pre-cooling mixed refrigerant compressor C-202 and the second pre-cooling mixed refrigerant water cooler WC-202, and the liquid pre-cooling mixed refrigerant is compressed by the pre-cooling mixed refrigerant pump P. The compressed and cooled gaseous pre-cooling mixed refrigerant and the compressed liquid pre-cooling mixed refrigerant are mixed by the first mixer MIX-1.

[0034] The deep cooling mixed refrigerant compression cooling system is used for compressing and cooling the deep cooling mixed refrigerant, and comprises a first deep cooling mixed refrigerant compressor C-301, a first deep cooling mixed refrigerant water cooler WC-301, a second deep cooling mixed refrigerant compressor C-302, a second deep cooling mixed refrigerant water cooler WC-302, a third deep cooling mixed refrigerant compressor C-303, and a third deep cooling mixed refrigerant water cooler WC-303 connected in sequence through pipelines. In operation, the deep cooling mixed refrigerant passes through the above devices in the above sequence. The first deep cooling mixed refrigerant compressor C-301, the second deep cooling mixed refrigerant compressor C-302, and the third deep cooling mixed refrigerant compressor C-303 are used for compressing the deep cooling mixed refrigerant, and the first deep cooling mixed refrigerant water cooler WC-301, the second deep cooling mixed refrigerant water cooler WC-302, and the third deep cooling mixed refrigerant water cooler WC-303 are used for cooling the deep cooling mixed refrigerant after each compression.

[0035] The primary heat exchange system is used for dividing the pre-cooling mixed refrigerant after cooling in the pre-cooling mixed refrigerant compression cooling system into gas-liquid two phases, and throttling and cooling the liquid phase pre-cooling mixed refrigerant, and the throttled and cooled pre-cooling mixed refrigerant is used for cooling the gas-liquid two phase pre-cooling mixed refrigerant, the hydrogen after compression and cooling in the hydrogen compression cooling system, and the deep cooling mixed refrigerant after compression and cooling in the deep cooling mixed refrigerant compression cooling system.

[0036] Specifically, the primary heat exchange system comprises a second gas-liquid separator V2, a first throttling valve VLV1, a second mixer MIX-2, and a first heat exchanger HEX1. The second gas-liquid separator V2 is used for dividing the pre-cooling mixed refrigerant after compression and cooling in the pre-cooling mixed refrigerant compression cooling system into gas-liquid two phases and entering the first heat exchanger HEX1. The first throttling valve VLV1 is used for throttling and cooling the liquid phase pre-cooling mixed refrigerant from the first heat exchanger HEX1. The second mixer MIX-2 is used for receiving the pre-cooling mixed refrigerant after throttling and cooling in the first throttling valve VLV1. The first heat exchanger HEX1 is used for cooling the gas-liquid two phase pre-cooling mixed refrigerant from the second gas-liquid separator V2, the hydrogen after compression and cooling in the hydrogen compression cooling system, and the deep cooling mixed refrigerant after compression and cooling in the deep cooling mixed refrigerant compression cooling system by using the pre-cooling mixed refrigerant after throttling and cooling in the first throttling valve VLV1.

[0037] The secondary heat exchange system is used to divide the pre-cooling mixed refrigerant cooled in the primary heat exchange system into gas-liquid two-phase, and to throttle and cool the liquid-phase pre-cooling mixed refrigerant, the pre-cooling mixed refrigerant after throttling and cooling is used to cool the gas-liquid two-phase pre-cooling mixed refrigerant, hydrogen from the primary heat exchange system and deep cooling mixed refrigerant, and the pre-cooling mixed refrigerant after absorbing heat is returned to the primary heat exchange system to cool the hydrogen, pre-cooling mixed refrigerant and deep cooling mixed refrigerant.

[0038] Specifically, the secondary heat exchange system comprises a third gas-liquid separator V3, a second throttle valve VLV2, a third mixer MIX-3 and a second heat exchanger HEX2. The third gas-liquid separator V3 is used to divide the pre-cooling mixed refrigerant cooled in the first heat exchanger HEX1 into gas-liquid two-phase, and the pre-cooling mixed refrigerant enters the second heat exchanger HEX2. The second throttle valve VLV2 is used to throttle and cool the liquid-phase pre-cooling mixed refrigerant from the second heat exchanger HEX2. The third mixer MIX-3 is used to receive the pre-cooling mixed refrigerant after throttling and cooling in the second throttle valve VLV2. The second heat exchanger HEX2 is used to cool the gas-liquid two-phase pre-cooling mixed refrigerant from the third gas-liquid separator V3, and hydrogen and deep cooling mixed refrigerant cooled in the first heat exchanger HEX1 by using the pre-cooling mixed refrigerant after throttling and cooling in the second throttle valve VLV2.

[0039] The tertiary heat exchange system is used to throttle and cool the pre-cooling mixed refrigerant cooled in the secondary heat exchange system, the pre-cooling mixed refrigerant after throttling and cooling is used to cool hydrogen, deep cooling mixed refrigerant and pre-cooling mixed refrigerant from the secondary heat exchange system, and the pre-cooling mixed refrigerant after absorbing heat is returned to the secondary heat exchange system to cool the hydrogen, pre-cooling mixed refrigerant and deep cooling mixed refrigerant.

[0040] Specifically, the tertiary heat exchange system comprises a third throttle valve VLV3 and a third heat exchanger HEX3. The third throttle valve VLV3 is used to throttle and cool the pre-cooling mixed refrigerant from the third heat exchanger HEX3. The third heat exchanger HEX3 is used to cool hydrogen, pre-cooling mixed refrigerant and deep cooling mixed refrigerant cooled in the second heat exchanger HEX2 by using the pre-cooling mixed refrigerant after throttling and cooling in the third throttle valve VLV3.

[0041] For the primary heat exchange system, the secondary heat exchange system, and the tertiary heat exchange system, it is also necessary to point out that the pre-cooling agent is a pre-cooling mixed refrigerant composed of methane, ethane, propane, n-pentane, nitrogen, and ethylene; the pre-cooling mixed refrigerant after absorbing heat in the third heat exchanger HEX3 enters the third mixer MIX-3 and is mixed with the pre-cooling mixed refrigerant from the second throttling valve VLV2, the pre-cooling mixed refrigerant after mixing in the third mixer MIX-3 enters the second heat exchanger HEX2 to cool the hydrogen and the cryogenic mixed refrigerant passing through, and then enters the second mixer MIX2 to mix with the pre-cooling mixed refrigerant from the first throttling valve VLV1, the pre-cooling mixed refrigerant after mixing in the second mixer MIX2 enters the first heat exchanger HEX1 to cool the hydrogen and the cryogenic mixed refrigerant passing through, and then enters the pre-cooling mixed refrigerant compression cooling system, so as to realize the recycling of the pre-cooling mixed refrigerant.

[0042] The quaternary heat exchange system is used to divide the cryogenic mixed refrigerant cooled in the tertiary heat exchange system into two parts, and one part of the cryogenic mixed refrigerant is expanded and cooled, and the cryogenic mixed refrigerant after expansion and cooling is used to cool the other part of the cryogenic mixed refrigerant and the hydrogen from the tertiary heat exchange system, and one part of the cryogenic mixed refrigerant after absorbing heat returns to the tertiary heat exchange system to cool the hydrogen, the pre-cooling mixed refrigerant, and the cryogenic mixed refrigerant passing through.

[0043] Specifically, the quaternary heat exchange system includes a first separator TEE-1, a first expander E-1, a fourth heat exchanger HEX4, and a fourth mixer MIX-4. The first separator TEE-1 is used to divide the cryogenic mixed refrigerant cooled in the third heat exchanger HEX3 and enter the first expander E-1 and the fourth heat exchanger HEX4 respectively. The first expander E-1 is used to expand and cool the cryogenic mixed refrigerant from the first separator TEE-1. The fourth heat exchanger HEX4 is used to cool the hydrogen cooled in the third heat exchanger HEX3 and the cryogenic mixed refrigerant not expanded and cooled from the first separator TEE-1 by using the cryogenic mixed refrigerant after expansion and cooling in the first expander E-1. The fourth mixer MIX-4 is used to receive the cryogenic mixed refrigerant after absorbing heat in the fourth heat exchanger HEX4.

[0044] The quinary heat exchange system is used to divide the cryogenic mixed refrigerant cooled in the quaternary heat exchange system into two parts, and one part of the cryogenic mixed refrigerant is expanded and cooled, and the cryogenic mixed refrigerant after expansion and cooling is used to cool the other part of the cryogenic mixed refrigerant and the hydrogen from the quaternary heat exchange system, and one part of the cryogenic mixed refrigerant after absorbing heat returns to the quaternary heat exchange system to cool the hydrogen and the cryogenic mixed refrigerant passing through.

[0045] Specifically, the five-stage heat exchange system comprises a second separator TEE-2, a second expander E-2, a fifth heat exchanger HEX5, and a fifth mixer MIX-5. The second separator TEE-2 is configured to split the cryogenic mixed refrigerant cooled by the fourth heat exchanger HEX4 into two parts, one of which enters the second expander E-2 and the other of which enters the fifth heat exchanger HEX5. The second expander E-2 is configured to expand and cool the cryogenic mixed refrigerant from the second separator TEE-2. The fifth heat exchanger HEX5 is configured to cool the hydrogen cooled by the fourth heat exchanger HEX4 and the cryogenic mixed refrigerant not expanded and cooled in the second separator TEE-2 using the cryogenic mixed refrigerant expanded and cooled by the second expander E-2. The fifth mixer MIX-5 is configured to receive the cryogenic mixed refrigerant after absorbing heat in the fifth heat exchanger HEX5.

[0046] The six-stage heat exchange system is configured to expand and cool the cryogenic mixed refrigerant cooled by the five-stage heat exchange system, and the cryogenic mixed refrigerant after being expanded and cooled is used to cool the hydrogen from the five-stage heat exchange system to obtain low-temperature supercritical hydrogen.

[0047] Specifically, the six-stage heat exchange system comprises a third expander E-3 and a sixth heat exchanger HEX6. The third expander E-3 is configured to expand and cool the cryogenic mixed refrigerant cooled by the fifth heat exchanger HEX5. The sixth heat exchanger HEX6 is configured to cool the hydrogen cooled by the fifth heat exchanger HEX5 using the cryogenic mixed refrigerant cooled by the third expander E-3 to obtain low-temperature supercritical hydrogen.

[0048] For the four-stage heat exchange system, the five-stage heat exchange system, and the six-stage heat exchange system, it should be further noted that the refrigerant is a cryogenic mixed refrigerant, and the composition is hydrogen, helium, and neon. After the cryogenic mixed refrigerant after absorbing heat in the sixth heat exchanger HEX6 cools the hydrogen passing through the fifth heat exchanger HEX5, it is mixed with the cryogenic mixed refrigerant after absorbing heat in the second expander E-2 in the fifth mixer MIX-5. After the cryogenic mixed refrigerant mixed in the fifth mixer MIX-5 cools the hydrogen passing through the fourth heat exchanger HEX4, it is mixed with the cryogenic mixed refrigerant after absorbing heat in the first expander E-1 in the fourth mixer MIX-4. After the cryogenic mixed refrigerant mixed in the fourth mixer MIX-4 cools the hydrogen passing through the third heat exchanger HEX3, it is first cooled by the hydrogen passing through the second heat exchanger HEX2, and then cooled by the hydrogen passing through the first heat exchanger HEX1. After that, it enters the cryogenic mixed refrigerant compression cooling system, thereby realizing the recycling of the cryogenic mixed refrigerant.

[0049] The hydrogen storage tank CT is used to store the low-temperature supercritical hydrogen cooled in the sixth heat exchanger HEX6. The hydrogen gas sequentially passes through the hydrogen compression cooling system, the first-stage heat exchange system, the second-stage heat exchange system, the third-stage heat exchange system, the fourth-stage heat exchange system, the fifth-stage heat exchange system, and the sixth-stage heat exchange system, and finally enters the hydrogen storage tank CT.

[0050] The working process of the low-temperature supercritical hydrogen storage system using the two-stage parallel mixed refrigerant refrigeration is as follows:

[0051] First, the hydrogen gas is introduced into the hydrogen compression cooling system, the pre-cooling mixed refrigerant is introduced into the pre-cooling mixed refrigerant compression cooling system, and the deep cooling mixed refrigerant is introduced into the deep cooling mixed refrigerant compression cooling system.

[0052] The hydrogen gas sequentially passes through the first hydrogen compressor C-101, the first hydrogen water cooler WC-101, the second hydrogen compressor C-102, the second hydrogen water cooler WC-102, the third hydrogen compressor C-103, the third hydrogen water cooler WC-103, the fourth hydrogen compressor C-104, the fourth hydrogen water cooler WC-104, the fifth hydrogen compressor C-105, and the fifth hydrogen water cooler WC-105 in the hydrogen compression cooling system to achieve compression cooling.

[0053] The pre-cooling mixed refrigerant is first compressed by the first pre-cooling mixed refrigerant compressor C-201 and then cooled by the first pre-cooling mixed refrigerant water cooler WC-201 in the pre-cooling mixed refrigerant compression cooling system. The cooled pre-cooling mixed refrigerant enters the first gas-liquid separator V1 for gas-liquid separation. The gaseous pre-cooling mixed refrigerant is compressed by the second pre-cooling mixed refrigerant compressor C-202 and cooled by the second pre-cooling mixed refrigerant water cooler WC-202. The liquid pre-cooling mixed refrigerant is compressed by the pre-cooling mixed refrigerant pump P. The compressed gaseous pre-cooling mixed refrigerant and the compressed liquid pre-cooling mixed refrigerant are mixed by the first mixer MIX-1.

[0054] The deep cooling mixed refrigerant sequentially passes through the first deep cooling mixed refrigerant compressor C-301, the first deep cooling mixed refrigerant water cooler WC-301, the second deep cooling mixed refrigerant compressor C-302, the second deep cooling mixed refrigerant water cooler WC-302, the third deep cooling mixed refrigerant compressor C-303, and the third deep cooling mixed refrigerant water cooler WC-303 in the deep cooling mixed refrigerant compression cooling system to achieve compression cooling.

[0055] Then, the hydrogen compressed and cooled by the hydrogen compression and cooling system and the deep cooling mixed refrigerant compressed and cooled by the deep cooling mixed refrigerant compression and cooling system are introduced into the first heat exchanger HEX1 in the primary heat exchange system. The pre-cooling mixed refrigerant mixed by the first mixer MIX-1 is introduced into the second gas-liquid separator V2 in the primary heat exchange system for gas-liquid separation, and the gaseous phase and the liquid phase pre-cooling mixed refrigerant after the separation are introduced into the first heat exchanger HEX1.

[0056] The liquid phase pre-cooling mixed refrigerant cooled by the first heat exchanger HEX1 is throttled by the first throttle valve VLV1, and the pre-cooling mixed refrigerant after the throttling is introduced back into the first heat exchanger HEX1 as the refrigerant of the primary heat exchange system and cools the hydrogen, the deep cooling mixed refrigerant and the gaseous-liquid two-phase pre-cooling mixed refrigerant in the first heat exchanger HEX1. The pre-cooling mixed refrigerant as the refrigerant is heated and its temperature is raised, and the hydrogen and the deep cooling mixed refrigerant cooled by the primary heat exchange system are introduced into the second heat exchanger HEX2.

[0057] The gaseous phase pre-cooling mixed refrigerant cooled by the first heat exchanger HEX1 is introduced into the third gas-liquid separator V3 in the secondary heat exchange system for gas-liquid separation, and the gaseous phase and the liquid phase pre-cooling mixed refrigerant after the separation are introduced into the second heat exchanger HEX2.

[0058] Further, the liquid phase pre-cooling mixed refrigerant cooled by the second heat exchanger HEX2 is throttled by the second throttle valve VLV2, and the pre-cooling mixed refrigerant after the throttling is introduced back into the second heat exchanger HEX2 as the refrigerant of the secondary heat exchange system and cools the hydrogen, the deep cooling mixed refrigerant and the gaseous-liquid two-phase pre-cooling mixed refrigerant in the second heat exchanger HEX2. The pre-cooling mixed refrigerant as the refrigerant is heated and its temperature is raised, and the hydrogen and the deep cooling mixed refrigerant cooled by the secondary heat exchange system are introduced into the third heat exchanger HEX3.

[0059] The gaseous phase pre-cooling mixed refrigerant cooled by the second heat exchanger HEX2 is introduced into the third heat exchanger HEX3 in the tertiary heat exchange system, and then throttled by the third throttle valve VLV3. The pre-cooling mixed refrigerant after the throttling is introduced back into the third heat exchanger HEX3 as the refrigerant of the tertiary heat exchange system and cools the hydrogen, the deep cooling mixed refrigerant and the pre-cooling mixed refrigerant in the third heat exchanger HEX3. The pre-cooling mixed refrigerant as the refrigerant is heated and its temperature is raised, and the hydrogen cooled by the third heat exchanger HEX3 is introduced into the fourth heat exchanger HEX4.

[0060] The pre-cooling mixed refrigerant after absorbing the heat in the third heat exchanger HEX3 and the pre-cooling mixed refrigerant after being throttled and cooled by the second throttle valve VLV2 are introduced into the third mixer MIX-3 in the secondary heat exchange system to be mixed, the mixed pre-cooling mixed refrigerant is introduced into the second heat exchanger HEX2 in the secondary heat exchange system to continue to cool the hydrogen and the pre-cooling mixed refrigerant in the secondary heat exchange system as the refrigerant, and the temperature of the pre-cooling mixed refrigerant is increased after absorbing the heat.

[0061] The pre-cooling mixed refrigerant after absorbing the heat in the second heat exchanger HEX2 and the pre-cooling mixed refrigerant after being throttled and cooled by the first throttle valve VLV1 are introduced into the second mixer MIX-2 in the primary heat exchange system to be mixed, the mixed pre-cooling mixed refrigerant is introduced into the first heat exchanger HEX1 in the primary heat exchange system to continue to cool the hydrogen and the pre-cooling mixed refrigerant in the primary heat exchange system as the refrigerant, and the temperature of the pre-cooling mixed refrigerant is increased after absorbing the heat.

[0062] The pre-cooling mixed refrigerant after absorbing the heat in the first heat exchanger HEX1 is introduced back to the pre-cooling mixed refrigerant compression cooling system to complete the closed loop circulation of the pre-cooling mixed refrigerant.

[0063] Then, the cryogenic mixed refrigerant after being cooled by the tertiary heat exchange system is introduced into the first separator TEE-1 in the quaternary heat exchange system to be divided, a part of the cryogenic mixed refrigerant is introduced into the fourth heat exchanger HEX4, another part of the cryogenic mixed refrigerant is introduced into the first expander E-1 to be expanded and cooled, and the part of the cryogenic mixed refrigerant is introduced into the fourth heat exchanger HEX4 as the refrigerant of the quaternary heat exchange system after being expanded and cooled, and the hydrogen and the cryogenic mixed refrigerant not being expanded and cooled in the fourth heat exchanger HEX4 are cooled, the part of the cryogenic mixed refrigerant as the refrigerant is increased in temperature after absorbing the heat, and the hydrogen after being cooled by the fourth heat exchanger HEX4 is introduced into the fifth heat exchanger HEX5.

[0064] The cryogenic mixed refrigerant after being cooled by the fourth heat exchanger HEX4 is introduced into the second separator TEE-2 in the quinary heat exchange system to be divided, a part of the cryogenic mixed refrigerant is introduced into the fifth heat exchanger HEX5, another part of the cryogenic mixed refrigerant is introduced into the second expander E-2 to be expanded and cooled, and the part of the cryogenic mixed refrigerant is introduced into the fifth heat exchanger HEX5 as the refrigerant of the quinary heat exchange system after being expanded and cooled, and the hydrogen and the cryogenic mixed refrigerant not being expanded and cooled in the fifth heat exchanger HEX5 are cooled, the part of the cryogenic mixed refrigerant as the refrigerant is increased in temperature after absorbing the heat, and the hydrogen after being cooled by the fifth heat exchanger HEX5 is introduced into the sixth heat exchanger HEX6.

[0065] The cryogenic mixed refrigerant cooled by the fifth heat exchanger HEX5 is introduced into the third expander E3 in the six-stage heat exchange system for expansion and temperature drop. The cryogenic mixed refrigerant, as the refrigerant of the six-stage heat exchange system, is introduced into the sixth heat exchanger HEX6 after the expansion and temperature drop, and cools the hydrogen in the sixth heat exchanger HEX6 to obtain low-temperature supercritical hydrogen. The cryogenic mixed refrigerant, as the refrigerant, is heated after absorbing heat, and the obtained low-temperature supercritical hydrogen is introduced into the hydrogen storage tank CT and stored.

[0066] The cryogenic mixed refrigerant after absorbing heat in the sixth heat exchanger HEX6 is introduced into the fifth heat exchanger HEX5 of the five-stage heat exchange system, and continues to cool the hydrogen and the cryogenic mixed refrigerant without expansion and temperature drop in the five-stage heat exchange system as the refrigerant, and is heated after absorbing heat.

[0067] The part of the cryogenic mixed refrigerant after absorbing heat in the fifth heat exchanger HEX5 and the cryogenic mixed refrigerant after absorbing heat in the fifth heat exchanger HEX5 introduced by the second expander E-2 are introduced into the fifth mixer MIX-5 in the five-stage heat exchange system for mixing. The mixed cryogenic mixed refrigerant is introduced into the fourth heat exchanger HEX4 in the four-stage heat exchange system, and continues to cool the hydrogen, the pre-cooling mixed refrigerant and the cryogenic mixed refrigerant without expansion and temperature drop in the four-stage heat exchange system as the refrigerant, and is heated after absorbing heat.

[0068] The part of the cryogenic mixed refrigerant after absorbing heat in the fourth heat exchanger HEX4 and the cryogenic mixed refrigerant after absorbing heat in the fourth heat exchanger HEX4 introduced by the first expander E-1 are introduced into the fourth mixer MIX-4 in the four-stage heat exchange system for mixing. The mixed cryogenic mixed refrigerant is introduced into the third heat exchanger HEX3 in the three-stage heat exchange system, and continues to cool the hydrogen, the pre-cooling mixed refrigerant and the cryogenic mixed refrigerant in the three-stage heat exchange system as the refrigerant, and is heated after absorbing heat.

[0069] The part of the cryogenic mixed refrigerant after absorbing heat in the third heat exchanger HEX3 is introduced into the second heat exchanger HEX2 in the two-stage heat exchange system, and continues to cool the hydrogen, the pre-cooling mixed refrigerant and the cryogenic mixed refrigerant in the two-stage heat exchange system as the refrigerant, and is heated after absorbing heat.

[0070] The part of the cryogenic mixed refrigerant after absorbing heat in the second heat exchanger HEX2 is introduced into the first heat exchanger HEX1 in the one-stage heat exchange system, and continues to cool the hydrogen, the pre-cooling mixed refrigerant and the cryogenic mixed refrigerant in the one-stage heat exchange system as the refrigerant, and is heated after absorbing heat.

[0071] The part of the cryogenic mixed refrigerant after absorbing heat in the first heat exchanger HEX1 is introduced back into the cryogenic mixed refrigerant compression cooling system to complete the closed loop circulation of the cryogenic mixed refrigerant.

[0072] In the present embodiment, the initial pressure of hydrogen is 110 kPa, the initial temperature is 35℃, and the flow rate is 100 kg / h. Different components and flow rates of the pre-cooling mixed refrigerant and the deep cooling mixed refrigerant can be set to obtain different total energy consumption, unit energy consumption, and energy consumption reduction percentage compared to the unit energy consumption of the traditional hydrogen liquefaction process, as shown in Table 1.

[0073] Table 1 Total energy consumption, unit energy consumption, and relative energy consumption reduction percentage of the system under different parameters

[0074]

[0075]

[0076] Parameter one can be set as follows: in the pre-cooling mixed refrigerant, the molar component proportions of methane, ethane, propane, n-pentane, nitrogen, and ethylene are 17.39%, 5.07%, 18.60%, 24.05%, 6.01%, and 28.87%, respectively, and the molar flow rate of the pre-cooling mixed refrigerant is 66.19 kmol / h; in the deep cooling mixed refrigerant, the molar component proportions of hydrogen, neon, and helium are 6.02%, 11.39%, and 82.59%, respectively, and the molar flow rate of the deep cooling mixed refrigerant is 170.23 kmol / h. Through simulation calculation, it is obtained that the total energy consumption of the present low-temperature supercritical hydrogen storage system under the present parameters is 6573 kW, the unit energy consumption is 6.573 kWh / kg, and the energy consumption is reduced by 47.42%-56.18% compared to the unit energy consumption of the traditional hydrogen liquefaction process (hydrogen liquefaction: 12.5-15 kWh / kg).

[0077] Parameter two can be set as follows: in the pre-cooling mixed refrigerant, the molar component proportions of methane, ethane, propane, n-pentane, nitrogen, and ethylene are 16.34%, 8.54%, 19.62%, 29.25%, 7.11%, and 19.15%, respectively, and the molar flow rate of the pre-cooling mixed refrigerant is 64.14 kmol / h; in the deep cooling mixed refrigerant, the molar component proportions of hydrogen, neon, and helium are 5.55%, 8.25%, and 86.21%, respectively, and the molar flow rate of the deep cooling mixed refrigerant is 183.07 kmol / h. Through simulation calculation, it is obtained that the total energy consumption of the present low-temperature supercritical hydrogen storage system under the present parameters is 6467 kW, the unit energy consumption is 6.467 kWh / kg, and the energy consumption is reduced by 48.26%-56.89% compared to the unit energy consumption of the traditional hydrogen liquefaction process (hydrogen liquefaction: 12.5-15 kWh / kg). Compared to parameter one, parameter two changes the component proportion of the mixed refrigerant, reduces the molar flow rate of the pre-cooling mixed refrigerant, and increases the molar flow rate of the deep cooling mixed refrigerant, so that the total energy consumption and the unit energy consumption of the system are both reduced.

[0078] The parameter three can be set: the molar component proportions of methane, ethane, propane, n-pentane, nitrogen and ethylene in the pre-cooling mixed refrigerant are 18.44%, 12.11%, 19.04%, 27.88%, 4.62% and 17.91% respectively, the molar flow of the pre-cooling mixed refrigerant is 63.89 kmol / h, the molar component proportions of hydrogen, neon and helium in the deep cooling mixed refrigerant are 7.67%, 11.89% and 80.44% respectively, and the molar flow of the deep cooling mixed refrigerant is 166.21 kmol / h. According to the simulation calculation, the total energy consumption of the low-temperature supercritical hydrogen storage system under the parameter three is 6438 kW, and the unit energy consumption is 6.438 kWh / kg. Compared with the unit energy consumption of the traditional hydrogen liquefaction process (hydrogen liquefaction: 12.5-15 kWh / kg), the energy consumption is reduced by 48.50%-57.08%. Compared with the parameter one, the parameter three changes the mixed refrigerant component ratio and reduces the molar flow of the pre-cooling mixed refrigerant and the deep cooling mixed refrigerant, so that the total energy consumption and the unit energy consumption of the system are reduced.

[0079] Therefore, the parameter three has better effect, and in actual situation, the parameter can also be set according to actual needs.

[0080] Effects of the embodiment

[0081] According to the low-temperature supercritical hydrogen storage system using two-stage parallel mixed refrigerant refrigeration provided in the embodiment, because the system includes a hydrogen compression cooling system, a pre-cooling mixed refrigerant compression cooling system, a deep cooling mixed refrigerant compression cooling system, a first heat exchange system, a second heat exchange system, a third heat exchange system, a fourth heat exchange system, a fifth heat exchange system and a sixth heat exchange system, the hydrogen is converted into low-temperature supercritical hydrogen, the low-temperature supercritical hydrogen has the characteristics of high density and not easy to evaporate and lose, so that the low-temperature supercritical hydrogen storage system has the characteristics of high storage density, good safety, not needing thick and heavy pressure-resistant containers and not easy to have hydrogen leakage, and in the embodiment, the pre-cooling mixed refrigerant throttling refrigeration and the deep cooling mixed refrigerant expansion method are used, the mixed refrigerant is in closed loop circulation in the system, and the hydrogen and the deep cooling mixed refrigerant are pre-cooled by the pre-cooling mixed refrigerant, so that the cooling of the hydrogen by the mixed refrigerant can be fully utilized, the production cost is reduced, and the cooling effect is improved.

[0082] Therefore, the low-temperature supercritical hydrogen storage system using two-stage parallel mixed refrigerant refrigeration provided in the embodiment has the characteristics of low cost, simplicity, high storage efficiency, good storage effect, high storage density, not needing thick and heavy pressure-resistant containers, not easy to have evaporation loss and leakage, good safety and excellent circulation performance.

[0083] The above embodiment is a preferred case of the present application and does not limit the protection scope of the present application.

Claims

1. A low-temperature supercritical hydrogen storage system utilizing a two-stage parallel mixed refrigerant cooling system, characterized in that, include: Hydrogen compression and cooling system, used to compress and cool hydrogen; A pre-cooled mixed refrigerant compression cooling system is used to compress and cool a pre-cooled mixed refrigerant. Cryogenic mixed refrigerant compression cooling system, used to compress and cool cryogenic mixed refrigerants; A primary heat exchange system is used to split the precooled mixed refrigerant, after it has been cooled from the precooled mixed refrigerant compression cooling system, into a gas-liquid two-phase system, and to throttle and cool the liquid phase of the precooled mixed refrigerant. The throttled and cooled precooled mixed refrigerant is used to cool the gas-liquid two-phase precooled mixed refrigerant, the hydrogen from the hydrogen compression cooling system, and the cryogenic mixed refrigerant from the cryogenic mixed refrigerant compression cooling system. The secondary heat exchange system is used to split the pre-cooled mixed refrigerant cooled from the primary heat exchange system into a gas-liquid two-phase system, and to throttle and cool the liquid phase of the pre-cooled mixed refrigerant. The pre-cooled mixed refrigerant after throttling and cooling is used to cool the gas-liquid two-phase pre-cooled mixed refrigerant, the hydrogen from the primary heat exchange system, and the cryogenic mixed refrigerant. After absorbing heat, the pre-cooled mixed refrigerant returns to the primary heat exchange system to cool the hydrogen, the pre-cooled mixed refrigerant, and the cryogenic mixed refrigerant that it has passed through. A three-stage heat exchange system is used to throttle and cool the pre-cooled mixed refrigerant after it has been cooled from the two-stage heat exchange system. The throttled and cooled pre-cooled mixed refrigerant is used to cool the hydrogen, the cryogenic mixed refrigerant, and the pre-cooled mixed refrigerant from the two-stage heat exchange system. After absorbing heat, the pre-cooled mixed refrigerant returns to the two-stage heat exchange system to cool the hydrogen, the pre-cooled mixed refrigerant, and the cryogenic mixed refrigerant that it has passed through. A four-stage heat exchange system is used to split the cryogenic mixed refrigerant cooled from the three-stage heat exchange system into two parts, and to expand and cool one part of the cryogenic mixed refrigerant. The expanded and cooled cryogenic mixed refrigerant is used to cool the other part of the cryogenic mixed refrigerant and the hydrogen from the three-stage heat exchange system. After absorbing heat, a part of the cryogenic mixed refrigerant returns to the three-stage heat exchange system to cool the hydrogen, the pre-cooled mixed refrigerant, and the cryogenic mixed refrigerant that have passed through it. A five-stage heat exchange system is used to split the cryogenic mixed refrigerant cooled from the four-stage heat exchange system into two parts, and to expand and cool one part of the cryogenic mixed refrigerant. The expanded and cooled cryogenic mixed refrigerant is used to cool the other part of the cryogenic mixed refrigerant and the hydrogen from the four-stage heat exchange system. After absorbing heat, a part of the cryogenic mixed refrigerant returns to the four-stage heat exchange system to cool the hydrogen and the cryogenic mixed refrigerant that have passed through it. The six-stage heat exchange system is used to expand and cool the cryogenic mixed refrigerant after it has been cooled from the five-stage heat exchange system. The expanded and cooled cryogenic mixed refrigerant is then used to finally cool the hydrogen from the five-stage heat exchange system to obtain cryogenic supercritical hydrogen. A hydrogen storage tank for storing the cryogenic supercritical hydrogen from the sixth-stage heat exchange system; The hydrogen gas sequentially passes through the hydrogen compression and cooling system, the primary heat exchange system, the secondary heat exchange system, the tertiary heat exchange system, the quaternary heat exchange system, the quinary heat exchange system, and the sixth heat exchange system before finally entering the hydrogen storage tank. The precooled mixed refrigerant compression and cooling system includes a first precooled mixed refrigerant compressor, a first precooled mixed refrigerant water cooler, a first gas-liquid separator, a second precooled mixed refrigerant compressor, a second precooled mixed refrigerant water cooler, a precooled mixed refrigerant pump, and a first mixer. The first pre-cooled mixed refrigerant compressor is used to compress the pre-cooled mixed refrigerant. The first pre-cooled mixed refrigerant water cooler is used to cool the pre-cooled mixed refrigerant after it has been compressed by the first pre-cooled mixed refrigerant compressor. The first gas-liquid separator is used to separate the pre-cooled mixed refrigerant, after it has been cooled by the first pre-cooled mixed refrigerant water cooler, into two phases: gas and liquid. The second pre-cooled mixed refrigerant compressor is used to compress the gaseous pre-cooled mixed refrigerant. The second pre-cooled mixed refrigerant water cooler is used to cool the pre-cooled mixed refrigerant after it has been compressed by the second pre-cooled mixed refrigerant compressor. The pre-cooled mixed refrigerant pump is used to compress the liquid-phase pre-cooled mixed refrigerant. The first mixer is used to mix the precooled refrigerant cooled by the second precooled refrigerant water cooler and the precooled refrigerant compressed by the precooled refrigerant pump. The pre-cooling refrigerant mixture comprises methane, ethane, propane, n-pentane, nitrogen, and ethylene, with the molar percentages of methane, ethane, propane, n-pentane, nitrogen, and ethylene being 18.44%, 12.11%, 19.04%, 27.88%, 4.62%, and 17.91%, respectively. The cryogenic mixed refrigerant compression and cooling system includes a first cryogenic mixed refrigerant compressor, a first cryogenic mixed refrigerant water cooler, a second cryogenic mixed refrigerant compressor, a second cryogenic mixed refrigerant water cooler, a third cryogenic mixed refrigerant compressor, and a third cryogenic mixed refrigerant water cooler. The cryogenic mixed refrigerant passes sequentially through the above-mentioned equipment in the cryogenic mixed refrigerant compression and cooling system. The first cryogenic mixed refrigerant compressor, the second cryogenic mixed refrigerant compressor, and the third cryogenic mixed refrigerant compressor are used to compress the cryogenic mixed refrigerant. The first cryogenic mixed refrigerant water cooler, the second cryogenic mixed refrigerant water cooler, and the third cryogenic mixed refrigerant water cooler are used to cool the cryogenic mixed refrigerant after each compression. The cryogenic mixed refrigerant is composed of hydrogen, helium, and neon, with the molar proportions of hydrogen, neon, and helium being 7.67%, 11.89%, and 80.44%, respectively.

2. The low-temperature supercritical hydrogen storage system according to claim 1, characterized in that: in, The hydrogen compression and cooling system includes a first hydrogen compressor, a first hydrogen water cooler, a second hydrogen compressor, a second hydrogen water cooler, a third hydrogen compressor, a third hydrogen water cooler, a fourth hydrogen compressor, a fourth hydrogen water cooler, a fifth hydrogen compressor, and a fifth hydrogen water cooler. The hydrogen gas passes through the above-mentioned equipment sequentially in the hydrogen compression and cooling system, and the pressure of the hydrogen gas after compression and cooling by the hydrogen compression and cooling system is greater than the standard critical pressure. The first hydrogen compressor, the second hydrogen compressor, the third hydrogen compressor, the fourth hydrogen compressor, and the fifth hydrogen compressor are used to compress the hydrogen. The first hydrogen water cooler, the second hydrogen water cooler, the third hydrogen water cooler, the fourth hydrogen water cooler, and the fifth hydrogen water cooler are used to cool the hydrogen after each compression.

3. The low-temperature supercritical hydrogen storage system according to claim 1, characterized in that: in, The primary heat exchange system includes a second gas-liquid separator, a first throttle valve, a second mixer, and a first heat exchanger. The second gas-liquid separator is used to separate the pre-cooled mixed refrigerant, after compression and cooling by the pre-cooled mixed refrigerant compression and cooling system, into gas and liquid phases, which then enter the first heat exchanger. The first throttling valve is used to throttle and cool the liquid-phase pre-cooled refrigerant mixture from the first heat exchanger. The second mixer is used to receive the pre-cooled mixed refrigerant after it has been throttled and cooled by the first throttling valve. The first heat exchanger is used to cool the pre-cooled mixed refrigerant from the second gas-liquid separator, the hydrogen compressed and cooled in the hydrogen compression and cooling system, and the cryogenic mixed refrigerant compressed and cooled in the cryogenic mixed refrigerant compression and cooling system using the pre-cooled mixed refrigerant cooled by the first throttling valve.

4. The low-temperature supercritical hydrogen storage system according to claim 3, characterized in that: in, The secondary heat exchange system includes a third gas-liquid separator, a second throttle valve, a third mixer, and a second heat exchanger. The third gas-liquid separator is used to separate the pre-cooled mixed refrigerant, after being cooled by the first heat exchanger, into gas and liquid phases, which then enter the second heat exchanger. The second throttling valve is used to throttle and cool the liquid-phase pre-cooled refrigerant mixture from the second heat exchanger. The third mixer is used to receive the pre-cooled mixed refrigerant after it has been throttled and cooled by the second throttling valve. The second heat exchanger is used to cool the pre-cooled mixed refrigerant from the third gas-liquid separator, as well as the hydrogen and the cryogenic mixed refrigerant cooled in the first heat exchanger, using the pre-cooled mixed refrigerant cooled by the second throttling valve.

5. The low-temperature supercritical hydrogen storage system according to claim 4, Its features are: The three-stage heat exchange system includes a third throttling valve and a third heat exchanger. The third throttling valve is used to throttle and cool the pre-cooled mixed refrigerant from the third heat exchanger. The third heat exchanger is used to cool the hydrogen, the precooled mixed refrigerant, and the cryogenic mixed refrigerant after they have been cooled in the second heat exchanger by using the precooled mixed refrigerant cooled by the third throttle valve; After absorbing heat in the third heat exchanger, the pre-cooled mixed refrigerant enters the third mixer and mixes with the pre-cooled mixed refrigerant from the second throttle valve. The pre-cooled mixed refrigerant after being mixed in the third mixer enters the second heat exchanger to cool the hydrogen and the cryogenic mixed refrigerant that have passed through it. Then, it enters the second mixer to mix with the pre-cooled mixed refrigerant from the first throttle valve. The pre-cooled mixed refrigerant after being mixed in the second mixer enters the first heat exchanger to cool the hydrogen and the cryogenic mixed refrigerant that have passed through it. Finally, it enters the pre-cooled mixed refrigerant compression and cooling system, realizing the recycling of the pre-cooled mixed refrigerant.

6. The low-temperature supercritical hydrogen storage system according to claim 1, characterized in that: in, The four-stage heat exchange system includes a first separator, a first expander, a fourth heat exchanger, and a fourth mixer. The first separator is used to split the cryogenic mixed refrigerant, after being cooled by the three-stage heat exchange system, so that it enters the first expander and the fourth heat exchanger respectively. The first expander is used to expand and cool the cryogenic mixed refrigerant from the first separator. The fourth heat exchanger is used to cool the hydrogen gas that has been cooled in the three-stage heat exchange system and the cryogenic mixed refrigerant that has not been expanded and cooled in the first separator using the cryogenic mixed refrigerant that has been expanded and cooled by the first expander. The fourth mixer is used to receive the cryogenic mixed refrigerant after it has absorbed heat in the fourth heat exchanger.

7. The low-temperature supercritical hydrogen storage system according to claim 6, characterized in that: in, The five-stage heat exchange system includes a second separator, a second expander, a fifth heat exchanger, and a fifth mixer. The second separator is used to split the cryogenic mixed refrigerant, after being cooled by the fourth heat exchanger, so that it enters the second expander and the fifth heat exchanger respectively. The second expander is used to expand and cool the cryogenic mixed refrigerant from the second separator. The fifth heat exchanger is used to cool the hydrogen gas that has been cooled in the fourth heat exchanger and the cryogenic mixed refrigerant that has not been expanded and cooled in the second separator using the cryogenic mixed refrigerant that has been expanded and cooled in the second expander. The fifth mixer is used to receive the cryogenic mixed refrigerant after it has absorbed heat in the fifth heat exchanger.

8. The low-temperature supercritical hydrogen storage system according to claim 7, characterized in that: in, The six-stage heat exchange system includes a third expander and a sixth heat exchanger. The third expander is used to expand and cool the cryogenic mixed refrigerant after it has been cooled from the fifth heat exchanger. The sixth heat exchanger is used to cool the hydrogen gas that has been cooled in the fifth heat exchanger using the cryogenic mixed refrigerant that has been cooled by the third expander, in order to obtain the low-temperature supercritical hydrogen. After absorbing heat in the sixth heat exchanger, the cryogenic mixed refrigerant enters the fifth heat exchanger to cool the hydrogen in the fifth heat exchanger. Then, it enters the fifth mixer to mix with the cryogenic mixed refrigerant that has absorbed heat from the second expander. After being mixed in the fifth mixer, the cryogenic mixed refrigerant enters the fourth heat exchanger to cool the hydrogen. Then, it enters the fourth mixer to mix with the cryogenic mixed refrigerant that has absorbed heat from the first expander. After being mixed in the fourth mixer, the cryogenic mixed refrigerant enters the three-stage heat exchange system to cool the hydrogen. It then enters the second-stage heat exchange system to cool the hydrogen, and then enters the first-stage heat exchange system to cool the hydrogen. Finally, it enters the cryogenic mixed refrigerant compression and cooling system, thus achieving the recycling of the cryogenic mixed refrigerant.

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