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

Abstract

The application provides a low-temperature supercritical hydrogen storage system using two-stage series mixed refrigerant 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 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, a seventh heat exchange system and a hydrogen storage tank. The hydrogen passes through the hydrogen compression cooling system, the first heat exchange system, the second heat exchange system, the third heat exchange system, the fourth heat exchange system, the fifth heat exchange system, the sixth heat exchange system and the seventh heat exchange system in sequence and is converted into low-temperature supercritical hydrogen and stored in the 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 circulation 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 series mixed refrigerant. BACKGROUND

[0002] Hydrogen energy is a kind of green clean energy, which has the advantages of high efficiency, high calorific value, renewability and wide source, and is beneficial to solving the energy crisis and environmental pollution problems.

[0003] Hydrogen production and use is a complete system engineering, and hydrogen storage and transportation is an important part. The high-pressure gaseous storage method in the prior art is a method widely used at present, which stores hydrogen by pressurizing hydrogen to 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 in the prior art liquefies hydrogen into liquid hydrogen by 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, great technical difficulty and great evaporation loss in long-term storage.

[0004] Chinese patent CN109027660A discloses a supercritical hydrogen storage method and application of supercritical hydrogen, and specifically discloses that the storage method comprises the following steps: hydrogen gas meeting the pressure and purity is cooled to obtain supercritical hydrogen, and the supercritical hydrogen is input into a supercritical storage tank for storage, wherein the hydrogen is pre-cooled by liquid nitrogen LN, the temperature of the hydrogen is reduced to about 80K, and then the hydrogen enters two-stage turbine expansion pre-cooling. The number of refrigeration stages is selected and matched according to the actual system production amount, and finally the temperature of the hydrogen is cooled to a temperature greater than 33.145K to ensure the supercritical state. The process is complex, the cost is high, the stability and reliability need to be further verified, and the specific power consumption is 10kW / kg, which is relatively high.

[0005] Chinese patent CN110848559A discloses a supercritical liquid hydrogen storage system, and specifically discloses that the supercritical liquid hydrogen storage system includes a hydrogen treatment part for treating hydrogen into supercritical liquid hydrogen; the supercritical hydrogen storage part has a tank body for storing liquid hydrogen, and a cooling cover is arranged outside the tank body; the cooling part has a cooling unit for cooling the cooling cover, the supercritical hydrogen storage part includes an outer tank, a first heat insulation layer, a vacuum cavity, the cooling cover, a second heat insulation layer and an inner tank arranged in sequence from outside to inside, the cooling part includes a Stirling refrigerator, a temperature sensor and the cooling unit, the Stirling refrigerator has a cold head, the temperature sensor is arranged in the cooling cover, the temperature sensor is connected with the Stirling refrigerator, and the cooling unit includes a first cold lead, a second cold lead and a pulsating heat pipe, the first cold lead is connected with the cold head, the second cold lead is connected with the cooling cover, one end of the pulsating heat pipe is connected with the first cold lead, and the other end of the pulsating heat pipe is connected with the second cold lead, so as to realize cold exchange between the cold head and the cooling cover. Its process is complex, and the stability and reliability need to be further verified, and the hydrogen density is 40.13 kg / m 3 , which is relatively low.

[0006] Chinese patent CN208901068U discloses a supercritical hydrogen storage tank, and specifically discloses that the supercritical hydrogen storage tank includes an inner tank and an outer tank, a vacuum interlayer is arranged between the inner tank and the outer tank, and an insulating layer is arranged in the vacuum interlayer; the inner tank is provided with a filling pipe and an overpressure discharge pipeline, one end of the filling pipe is arranged at the bottom of the inner tank, the filling pipe is in communication with the inner tank, the other end of the filling pipe penetrates out of the outer tank, one end of the overpressure discharge pipeline is in communication with the inner tank, the other end of the overpressure discharge pipeline penetrates out of the outer tank, and a safety valve and a pressure gauge are arranged on the overpressure discharge pipeline; the outer tank is provided with a vacuum air exhaust pipe and a vacuum gauge, the vacuum air exhaust pipe is in communication with the vacuum interlayer, and the vacuum gauge is used for monitoring the vacuum degree of the vacuum interlayer. Its structure is complex, and the stability and reliability need to be further verified.

[0007] Chinese patent CN209705707U discloses a hydrogenation system based on cryogenic high-pressure hydrogen storage, and specifically discloses that the hydrogenation system includes 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, and the hydrogenation system further includes a cryogenic 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 cryogenic high-pressure hydrogen storage bottle through a pipeline, the outlet of the cryogenic high-pressure hydrogen storage bottle is connected with the other inlet of the mixer through a pipeline, and the outlet of the cryogenic high-pressure hydrogen storage bottle is also connected with the inlet of the vaporizer through a pipeline. Its process is complex, and the stability and reliability need to be further verified.

[0008] Chinese patent CN113446815A discloses a mixed refrigeration hydrogen liquefaction device and its use method, and specifically discloses that the hydrogen liquefaction device 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 in the pre-cooling section as the main cold quantity sources, the refrigerant refrigeration cycle is the main cold quantity source in the temperature range of 303K to 113K, the liquid nitrogen refrigeration cycle is the main cold quantity source in the temperature range of 130K to 80K, the hydrogen refrigeration cycle provides cold quantity in the temperature range of 80K to 20K, and most of the BOG generated in the 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 to provide a low-temperature supercritical hydrogen storage system using two-stage series mixed refrigerant refrigeration.

[0010] The application provides a low-temperature supercritical hydrogen storage system using two-stage series 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 divided in the first heat exchange system and the hydrogen from the hydrogen 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 divided in the second heat exchange system and the hydrogen from the first heat exchange system, and returning the pre-cooling mixed refrigerant after absorbing heat to the first heat exchange system to cool the hydrogen and the pre-cooling mixed refrigerant; a third heat exchange system for throttling and cooling the cooled pre-cooling mixed refrigerant from the second heat exchange system, using the throttled and cooled pre-cooling mixed refrigerant to cool the hydrogen and the 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 the hydrogen and the pre-cooling mixed refrigerant; a fourth heat exchange system for cooling the hydrogen from the third heat exchange system and the deep cooling mixed refrigerant from the deep cooling mixed refrigerant compression cooling system; 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, using the expanded and cooled deep cooling mixed refrigerant to cool the other part of the deep cooling mixed refrigerant and the 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 the hydrogen and the deep cooling mixed refrigerant; a sixth heat exchange system for dividing the cooled deep cooling mixed refrigerant from the fifth heat exchange system into two parts, expanding and cooling one part of the deep cooling mixed refrigerant, using the expanded and cooled deep cooling mixed refrigerant to cool the other part of the deep cooling mixed refrigerant and the hydrogen from the fifth heat exchange system, and returning the part of the deep cooling mixed refrigerant after absorbing heat to the fifth heat exchange system to cool the hydrogen and the deep cooling mixed refrigerant; a seventh heat exchange system for expanding and cooling the cooled deep cooling mixed refrigerant from the sixth heat exchange system, using the expanded and cooled deep cooling mixed refrigerant to finally cool the hydrogen from the sixth heat exchange system to obtain low-temperature supercritical hydrogen; and a hydrogen storage tank for storing the low-temperature supercritical hydrogen from the seventh 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, the sixth-stage heat exchange system and the seventh-stage heat exchange system in sequence, and finally enters the hydrogen storage tank.

[0011] In the low-temperature supercritical hydrogen storage system using two-stage serial mixed refrigerant refrigeration provided by the application, the hydrogen compression cooling system can further comprise 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 using two-stage serial mixed refrigerant refrigeration provided by the application, the pre-cooling mixed refrigerant compression cooling system can further comprise a first pre-cooling mixed refrigerant compressor, a first pre-cooling mixed refrigerant water cooler, a first gas-liquid separator, a second pre-cooling mixed refrigerant compressor, a second pre-cooling mixed refrigerant water cooler, a pre-cooling mixed refrigerant pump and a first mixer, the first pre-cooling mixed refrigerant compressor is used for compressing the pre-cooling mixed refrigerant, the first pre-cooling mixed refrigerant water cooler is used for cooling the pre-cooling mixed refrigerant compressed by the first pre-cooling mixed refrigerant compressor, the first gas-liquid separator is used for separating the pre-cooling mixed refrigerant cooled by the first pre-cooling mixed refrigerant water cooler into gas and liquid phases, the second pre-cooling mixed refrigerant compressor is used for compressing the gas-phase pre-cooling mixed refrigerant, the second pre-cooling mixed refrigerant water cooler is used for cooling the pre-cooling mixed refrigerant compressed by the second pre-cooling mixed refrigerant compressor, the pre-cooling mixed refrigerant pump is used for compressing the liquid-phase pre-cooling mixed refrigerant, and the first mixer is used for mixing the pre-cooling mixed refrigerant cooled by the second pre-cooling mixed refrigerant water cooler and the pre-cooling mixed refrigerant compressed by the pre-cooling mixed refrigerant pump.

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

[0014] In the low-temperature supercritical hydrogen storage system using two-stage series mixed refrigerant refrigeration provided by the application, the low-temperature supercritical hydrogen storage system can further have the following features: the first heat exchange system comprises 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 the throttling and cooling of the first throttling valve, and the first heat exchanger is used for cooling the pre-cooling mixed refrigerant from the second gas-liquid separator and the hydrogen compressed and cooled in the hydrogen compression cooling system by using the pre-cooling mixed refrigerant after the throttling and cooling of the first throttling valve.

[0015] In the low-temperature supercritical hydrogen storage system using two-stage series mixed refrigerant refrigeration provided by the application, the low-temperature supercritical hydrogen storage system can further have the following features: the second heat exchange system comprises 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 the throttling and cooling of 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 cooled in the first heat exchanger by using the pre-cooling mixed refrigerant after the throttling and cooling of the second throttling valve.

[0016] In the low-temperature supercritical hydrogen storage system using two-stage series 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 to throttle and cool the pre-cooling mixed refrigerant from the third heat exchanger, and the third heat exchanger is used to cool the hydrogen cooled in the second heat exchanger and the pre-cooling mixed refrigerant after being throttled and cooled by the third throttling valve.

[0017] In the low-temperature supercritical hydrogen storage system using two-stage series 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 to throttle and cool the pre-cooling mixed refrigerant from the third heat exchanger, and the third heat exchanger is used to cool the hydrogen cooled in the second heat exchanger and the pre-cooling mixed refrigerant after being throttled and cooled by the third throttling valve.

[0018] In the low-temperature supercritical hydrogen storage system using two-stage series 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 to throttle and cool the pre-cooling mixed refrigerant from the third heat exchanger, and the third heat exchanger is used to cool the hydrogen cooled in the second heat exchanger and the pre-cooling mixed refrigerant after being throttled and cooled by the third throttling valve.

[0019] In the low-temperature supercritical hydrogen storage system using two-stage series 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 to throttle and cool the pre-cooling mixed refrigerant from the third heat exchanger, and the third heat exchanger is used to cool the hydrogen cooled in the second heat exchanger and the pre-cooling mixed refrigerant after being throttled and cooled by the third throttling valve.

[0020] In the low-temperature supercritical hydrogen storage system using the two-stage series mixed refrigerant refrigeration provided by the application, the six-stage heat exchange system can further comprise a second separator, a second expander, a sixth heat exchanger, and a fifth mixer, the second separator is used for separating the cryogenic mixed refrigerant cooled by the fifth heat exchanger and entering the second expander and the sixth heat exchanger respectively, the second expander is used for expanding and cooling the cryogenic mixed refrigerant from the second separator, the sixth heat exchanger is used for cooling the cryogenic mixed refrigerant not expanded and cooled from the second separator and the hydrogen cooled in the fifth heat exchanger by using the cryogenic mixed refrigerant expanded and cooled by the second expander, and the fifth mixer is used for receiving the cryogenic mixed refrigerant after absorbing heat in the sixth heat exchanger.

[0021] In the low-temperature supercritical hydrogen storage system using the two-stage series mixed refrigerant refrigeration provided by the application, the six-stage heat exchange system can further comprise a second separator, a second expander, a sixth heat exchanger, and a fifth mixer, the second separator is used for separating the cryogenic mixed refrigerant cooled by the fifth heat exchanger and entering the second expander and the sixth heat exchanger respectively, the second expander is used for expanding and cooling the cryogenic mixed refrigerant from the second separator, the sixth heat exchanger is used for cooling the cryogenic mixed refrigerant not expanded and cooled from the second separator and the hydrogen cooled in the fifth heat exchanger by using the cryogenic mixed refrigerant expanded and cooled by the second expander, and the fifth mixer is used for receiving the cryogenic mixed refrigerant after absorbing heat in the sixth heat exchanger.

[0022] In the low-temperature supercritical hydrogen storage system using the two-stage series mixed refrigerant refrigeration provided by the application, the six-stage heat exchange system can further comprise a second separator, a second expander, a sixth heat exchanger, and a fifth mixer, the second separator is used for separating the cryogenic mixed refrigerant cooled by the fifth heat exchanger and entering the second expander and the sixth heat exchanger respectively, the second expander is used for expanding and cooling the cryogenic mixed refrigerant from the second separator, the sixth heat exchanger is used for cooling the cryogenic mixed refrigerant not expanded and cooled from the second separator and the hydrogen cooled in the fifth heat exchanger by using the cryogenic mixed refrigerant expanded and cooled by the second expander, and the fifth mixer is used for receiving the cryogenic mixed refrigerant after absorbing heat in the sixth heat exchanger.

[0023] In the low-temperature supercritical hydrogen storage system using the two-stage series mixed refrigerant refrigeration provided by the application, the six-stage heat exchange system can further comprise a second separator, a second expander, a sixth heat exchanger, and a fifth mixer, the second separator is used for separating the cryogenic mixed refrigerant cooled by the fifth heat exchanger and entering the second expander and the sixth heat exchanger respectively, the second expander is used for expanding and cooling the cryogenic mixed refrigerant from the second separator, the sixth heat exchanger is used for cooling the cryogenic mixed refrigerant not expanded and cooled from the second separator and the hydrogen cooled in the fifth heat exchanger by using the cryogenic mixed refrigerant expanded and cooled by the second expander, and the fifth mixer is used for receiving the cryogenic mixed refrigerant after absorbing heat in the sixth heat exchanger.

[0024] Effects of the application

[0025] The cryogenic supercritical hydrogen storage system utilizing a two-stage series mixed refrigerant cooling system according to the present invention comprises a hydrogen compression cooling system, a pre-cooled mixed refrigerant compression cooling system, a cryogenic mixed refrigerant compression cooling system, a primary heat exchange system, a secondary heat exchange system, a tertiary heat exchange system, a quaternary heat exchange system, a quinary heat exchange system, a sixth heat exchange system, a septum heat exchange system, and a hydrogen storage tank. This allows hydrogen to be converted into cryogenic supercritical hydrogen. Cryogenic supercritical hydrogen has the characteristics of high density and low evaporation loss. Therefore, this cryogenic supercritical hydrogen storage system utilizing a two-stage parallel mixed refrigerant cooling cycle has the characteristics of high storage density, good safety, no need for heavy and pressure-resistant containers, and low risk of hydrogen leakage. Furthermore, by using a pre-cooled mixed refrigerant to pre-cool the hydrogen and the cryogenic mixed refrigerant, the cooling effect of the mixed refrigerant can be fully utilized, reducing production costs, improving cooling efficiency, and ensuring good circulation performance of the mixed refrigerant within the system.

[0026] In summary, the low-temperature supercritical hydrogen storage system using a two-stage series mixed refrigerant provided by this invention has the characteristics of low cost, simplicity and ease of implementation, high storage density, no need for heavy and pressure-resistant containers, low risk of evaporation loss and leakage, good safety, and excellent cycle performance. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a low-temperature supercritical hydrogen storage system using a two-stage series mixed refrigerant cooling system in an embodiment of the present invention. Detailed Implementation

[0028] To make the technical means, creative features, objectives and effects of this invention easier to understand, the following embodiments are described in detail with reference to the accompanying drawings.

[0029] Example

[0030] Figure 1 This is a schematic diagram of a low-temperature supercritical hydrogen storage system that utilizes a two-stage series mixed refrigerant cooling system.

[0031] like Figure 1 As shown, this embodiment provides a low-temperature supercritical hydrogen storage system utilizing a two-stage series-connected mixed refrigerant cooling system, including a hydrogen compression cooling system, a pre-cooled mixed refrigerant compression cooling system, a cryogenic mixed refrigerant compression cooling system, a primary heat exchange system, a secondary heat exchange system, a tertiary heat exchange system, a quaternary heat exchange system, a quinary heat exchange system, a sixth heat exchange system, a septum heat exchange system, a septum heat exchange system, and a hydrogen storage tank. The details of each part are described below.

[0032] The hydrogen compression cooling system is used for hydrogen compression cooling, comprising 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. 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 hydrogen compression, 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 hydrogen cooling after each compression. The pressure of the compressed and cooled hydrogen is greater than the standard critical pressure of hydrogen.

[0033] The pre-cooled mixed refrigerant compression cooling system is used for pre-cooled mixed refrigerant compression cooling, comprising a first pre-cooled mixed refrigerant compressor C-201, a first pre-cooled mixed refrigerant water cooler WC-201, a first vapor-liquid separator V1, a second pre-cooled mixed refrigerant compressor C-202, a second pre-cooled mixed refrigerant water cooler WC-202, a pre-cooled mixed refrigerant pump P, and a first mixer MIX-1. The first pre-cooled mixed refrigerant compressor C-201 is used for pre-cooled mixed refrigerant compression. The first pre-cooled mixed refrigerant water cooler WC-201 is used for pre-cooled mixed refrigerant cooling after the compressor C-201. The first vapor-liquid separator V1 is used for pre-cooled mixed refrigerant cooling after the first pre-cooled mixed refrigerant water cooler WC-201, and the gas phase pre-cooled mixed refrigerant enters the second pre-cooled mixed refrigerant compressor C-202, and the liquid phase pre-cooled mixed refrigerant enters the pre-cooled mixed refrigerant pump P. The second pre-cooled mixed refrigerant compressor C-202 is used for gas phase pre-cooled mixed refrigerant compression. The second pre-cooled mixed refrigerant water cooler WC-202 is used for pre-cooled mixed refrigerant cooling after the second pre-cooled mixed refrigerant compressor C-202. The pre-cooled mixed refrigerant pump P is used for liquid phase pre-cooled mixed refrigerant compression. The first mixer MIX-1 is used for mixing the pre-cooled mixed refrigerant cooled by the second pre-cooled mixed refrigerant water cooler WC-202 and the pre-cooled mixed refrigerant compressed by the pre-cooled mixed refrigerant pump P.

[0034] When the pre-cooled mixed refrigerant passes through the pre-cooled mixed refrigerant compression cooling system, the pre-cooled mixed refrigerant is first compressed by the first pre-cooled mixed refrigerant compressor C-201, and then cooled by the first pre-cooled mixed refrigerant water cooler WC-201. The cooled pre-cooled mixed refrigerant enters the first gas-liquid separator V1 to be separated into gas and liquid phases. The gas-phase pre-cooled mixed refrigerant is compressed and cooled by the second pre-cooled mixed refrigerant compressor C-202 and the second pre-cooled mixed refrigerant water cooler WC-202. The liquid-phase pre-cooled mixed refrigerant is compressed by the pre-cooled mixed refrigerant pump P. The compressed gas-phase pre-cooled mixed refrigerant and the compressed liquid-phase pre-cooled mixed refrigerant are mixed by the first mixer MIX-1.

[0035] The deep-cooled mixed refrigerant compression cooling system is used for compressing and cooling the deep-cooled mixed refrigerant, and includes the first deep-cooled mixed refrigerant compressor C-301, the first deep-cooled mixed refrigerant water cooler WC-301, the second deep-cooled mixed refrigerant compressor C-302, the second deep-cooled mixed refrigerant water cooler WC-302, the third deep-cooled mixed refrigerant compressor C-303, and the third deep-cooled mixed refrigerant water cooler WC-303. In operation, the deep-cooled mixed refrigerant passes through the above devices in the above order in the deep-cooled mixed refrigerant compression cooling system. The first deep-cooled mixed refrigerant compressor C-301, the second deep-cooled mixed refrigerant compressor C-302, and the third deep-cooled mixed refrigerant compressor C-303 are used for compressing the deep-cooled mixed refrigerant, and the first deep-cooled mixed refrigerant water cooler WC-301, the second deep-cooled mixed refrigerant water cooler WC-302, and the third deep-cooled mixed refrigerant water cooler WC-303 are used for cooling the deep-cooled mixed refrigerant after each compression.

[0036] The primary heat exchange system is used for separating the cooled pre-cooled mixed refrigerant from the pre-cooled mixed refrigerant compression cooling system into gas and liquid phases, and throttling the liquid-phase pre-cooled mixed refrigerant to reduce the temperature. The pre-cooled mixed refrigerant after the temperature reduction is used for cooling the gas-liquid phase pre-cooled mixed refrigerant and the hydrogen from the hydrogen compression cooling system.

[0037] Specifically, the first 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 configured to separate the pre-cooled mixed refrigerant compressed and cooled by the pre-cooled mixed refrigerant compression and cooling system into gas-liquid two-phase, and then the gas-liquid two-phase pre-cooled mixed refrigerant enters the first heat exchanger HEX1. The first throttling valve VLV1 is configured to throttle and cool the liquid-phase pre-cooled mixed refrigerant from the first heat exchanger HEX1. The second mixer MIX-2 is configured to receive the pre-cooled mixed refrigerant throttled and cooled by the first throttling valve VLV1. The first heat exchanger HEX1 is configured to cool the gas-liquid two-phase pre-cooled mixed refrigerant from the second gas-liquid separator V2 and the hydrogen from the hydrogen compression and cooling system by using the pre-cooled mixed refrigerant throttled and cooled by the first throttling valve VLV1.

[0038] The second heat exchange system is configured to separate the pre-cooled mixed refrigerant cooled by the first heat exchange system into gas-liquid two-phase, throttle and cool the liquid-phase pre-cooled mixed refrigerant, and then the pre-cooled mixed refrigerant throttled and cooled is used to cool the gas-liquid two-phase pre-cooled mixed refrigerant and the hydrogen from the first heat exchange system. The pre-cooled mixed refrigerant after absorbing heat is returned to the first heat exchange system to cool the hydrogen and the pre-cooled mixed refrigerant.

[0039] Specifically, the second heat exchange system comprises a third gas-liquid separator V3, a second throttling valve VLV2, a third mixer MIX-3, and a second heat exchanger HEX2. The third gas-liquid separator V3 is configured to separate the pre-cooled mixed refrigerant cooled by the first heat exchanger HEX1 into gas-liquid two-phase, and then the gas-liquid two-phase pre-cooled mixed refrigerant enters the second heat exchanger HEX2. The second throttling valve VLV2 is configured to throttle and cool the liquid-phase pre-cooled mixed refrigerant from the second heat exchanger HEX2. The third mixer MIX-3 is configured to receive the pre-cooled mixed refrigerant throttled and cooled by the second throttling valve VLV2. The second heat exchanger HEX2 is configured to cool the gas-liquid two-phase pre-cooled mixed refrigerant from the third gas-liquid separator V3 and the hydrogen cooled in the first heat exchanger HEX1 by using the pre-cooled mixed refrigerant throttled and cooled by the second throttling valve VLV2.

[0040] The third heat exchange system is configured to throttle and cool the pre-cooled mixed refrigerant cooled by the second heat exchange system, and then the pre-cooled mixed refrigerant throttled and cooled is used to cool the pre-cooled mixed refrigerant and the hydrogen from the second heat exchange system. The pre-cooled mixed refrigerant after absorbing heat is returned to the second heat exchange system to cool the hydrogen and the pre-cooled mixed refrigerant.

[0041] Specifically, the third heat exchange system comprises a third throttling valve VLV3 and a third heat exchanger HEX3. The third throttling valve VLV3 is configured to throttle and cool the pre-cooling mixed refrigerant from the third heat exchanger HEX3. The third heat exchanger HEX3 is configured to cool the hydrogen cooled in the second heat exchanger HEX2 and the pre-cooling mixed refrigerant using the pre-cooling mixed refrigerant throttled and cooled by the third throttling valve VLV3.

[0042] For the first heat exchange system, the second heat exchange system, and the third heat exchange system, it is further noted that the pre-cooling agent is the pre-cooling mixed refrigerant, which comprises 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, mixes with the pre-cooling mixed refrigerant from the second throttling valve VLV2, and then enters the second heat exchanger HEX2 to cool the hydrogen. After that, the pre-cooling mixed refrigerant enters the second mixer MIX2 to mix with the pre-cooling mixed refrigerant from the first throttling valve VLV1, and then enters the first heat exchanger HEX1 to cool the hydrogen. After that, the pre-cooling mixed refrigerant enters the pre-cooling mixed refrigerant compression cooling system, so as to realize the recycling of the pre-cooling mixed refrigerant.

[0043] The fourth heat exchange system is configured to cool the hydrogen from the third heat exchange system and the deep cooling mixed refrigerant from the deep cooling mixed refrigerant compression cooling system.

[0044] Specifically, the fourth heat exchange system comprises a fourth heat exchanger HEX4. The fourth heat exchanger HEX4 is configured to cool the hydrogen cooled by the third heat exchanger and the deep cooling mixed refrigerant compressed and cooled by the deep cooling mixed refrigerant compression cooling system using the deep cooling mixed refrigerant.

[0045] The fifth heat exchange system is configured to divide the deep cooling mixed refrigerant cooled in the fourth heat exchange system into two parts, expand and cool one part of the deep cooling mixed refrigerant, and use the deep cooling mixed refrigerant after expansion and cooling to cool the other part of the deep cooling mixed refrigerant and the hydrogen from the fourth heat exchange system. The part of the deep cooling mixed refrigerant after absorbing heat returns to the fourth heat exchange system to cool the hydrogen and the deep cooling mixed refrigerant.

[0046] Specifically, the five-stage heat exchange system comprises a first separator TEE-1, a first expander E-1, a fifth heat exchanger HEX5, and a fourth mixer MIX-4. The first separator TEE-1 is configured to split the cryogenic mixed refrigerant cooled in the fourth heat exchanger HEX4 into two parts, and the two parts are respectively introduced into the first expander E-1 and the fifth heat exchanger HEX5. The first expander E-1 is configured to expand and cool the cryogenic mixed refrigerant from the first separator TEE-1. The fifth heat exchanger HEX5 is configured to cool the hydrogen gas cooled in the fourth heat exchanger HEX4 and the cryogenic mixed refrigerant not expanded and cooled in the first separator TEE-1 by using the cryogenic mixed refrigerant expanded and cooled in the first expander E-1. The fourth mixer MIX-4 is configured to receive the cryogenic mixed refrigerant after absorbing heat in the fifth heat exchanger HEX5.

[0047] The six-stage heat exchange system is configured to split the cryogenic mixed refrigerant cooled in the five-stage heat exchange system into two parts, expand and cool one part of the cryogenic mixed refrigerant, and cool the other part of the cryogenic mixed refrigerant and the hydrogen gas from the five-stage heat exchange system by using the cryogenic mixed refrigerant expanded and cooled. The part of the cryogenic mixed refrigerant after absorbing heat is returned to the five-stage heat exchange system to cool the hydrogen gas and the cryogenic mixed refrigerant.

[0048] Specifically, the six-stage heat exchange system comprises a second separator TEE-2, a second expander E-2, a sixth heat exchanger HEX6, and a fifth mixer MIX-5. The second separator TEE-2 is configured to split the cryogenic mixed refrigerant cooled in the fifth heat exchanger HEX5 into two parts, and the two parts are respectively introduced into the second expander E-2 and the sixth heat exchanger HEX6. The second expander E-2 is configured to expand and cool the cryogenic mixed refrigerant from the second separator TEE-2. The sixth heat exchanger HEX6 is configured to cool the hydrogen gas cooled in the fifth heat exchanger HEX5 and the cryogenic mixed refrigerant not expanded and cooled in the second separator TEE-2 by using the cryogenic mixed refrigerant expanded and cooled in the second expander E-2. The fifth mixer MIX-5 is configured to receive the cryogenic mixed refrigerant after absorbing heat in the sixth heat exchanger HEX6.

[0049] The seven-stage heat exchange system is configured to expand and cool the cryogenic mixed refrigerant cooled in the six-stage heat exchange system, and the cryogenic mixed refrigerant expanded and cooled is used to finally cool the hydrogen gas from the six-stage heat exchange system to obtain the low-temperature supercritical hydrogen.

[0050] Specifically, the seven-stage heat exchange system comprises a third expander E-3 and a seventh heat exchanger HEX7. The third expander E-3 is used to expand and cool the cooled cryogenic mixed refrigerant from the sixth heat exchanger HEX6. The seventh heat exchanger HEX7 is used to cool the hydrogen cooled in the sixth heat exchanger HEX6 using the cryogenic mixed refrigerant cooled by the third expander E-3, to obtain low-temperature supercritical hydrogen.

[0051] For the four-stage heat exchange system, the five-stage heat exchange system, the six-stage heat exchange system, and the seven-stage heat exchange system, it is further noted that the refrigerant is a cryogenic mixed refrigerant, and the composition is hydrogen, helium, and neon. After the cryogenic mixed refrigerant absorbs heat in the seventh heat exchanger HEX7, it enters the sixth heat exchanger HEX6 to cool the hydrogen, then enters the fifth mixer MIX-5 to mix with the cryogenic mixed refrigerant from the second expander E-2 after absorbing heat, the cryogenic mixed refrigerant mixed by the fifth mixer MIX-5 enters the fifth heat exchanger HEX5 to cool the hydrogen, then enters the fourth mixer MIX-4 to mix with the cryogenic mixed refrigerant from the first expander E-1 after absorbing heat, the cryogenic mixed refrigerant mixed by the fourth mixer MIX-4 enters the fourth heat exchanger HEX4 to cool the hydrogen, and then enters the cryogenic mixed refrigerant compression cooling system, so as to realize the recycling of the cryogenic mixed refrigerant.

[0052] The hydrogen storage tank CT is used to store the low-temperature supercritical hydrogen cooled in the seventh heat exchanger HEX7. 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 four-stage heat exchange system, the five-stage heat exchange system, the six-stage heat exchange system, and the seven-stage heat exchange system, and finally enters the hydrogen storage tank CT.

[0053] The working process of the low-temperature supercritical hydrogen storage system using the two-stage series mixed refrigerant refrigeration is as follows:

[0054] 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 cryogenic mixed refrigerant is introduced into the cryogenic mixed refrigerant compression cooling system.

[0055] The hydrogen gas sequentially passes through the first hydrogen gas compressor C-101, the first hydrogen gas water cooler WC-101, the second hydrogen gas compressor C-102, the second hydrogen gas water cooler WC-102, the third hydrogen gas compressor C-103, the third hydrogen gas water cooler WC-103, the fourth hydrogen gas compressor C-104, the fourth hydrogen gas water cooler WC-104, the fifth hydrogen gas compressor C-105, and the fifth hydrogen gas water cooler WC-105 in the hydrogen compression cooling system, to realize compression cooling.

[0056] The pre-cooling mixed refrigerant is 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 is separated into gas phase and liquid phase in the first gas-liquid separator V1. The separated gas phase 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 separated liquid phase pre-cooling mixed refrigerant is compressed by the pre-cooling mixed refrigerant pump P. The compressed gas phase pre-cooling mixed refrigerant and the compressed liquid phase pre-cooling mixed refrigerant are mixed by the first mixer MIX-1.

[0057] The cryogenic mixed refrigerant is sequentially compressed and cooled by the first cryogenic mixed refrigerant compressor C-301, the first cryogenic mixed refrigerant water cooler WC-301, the second cryogenic mixed refrigerant compressor C-302, the second cryogenic mixed refrigerant water cooler WC-302, the third cryogenic mixed refrigerant compressor C-303, and the third cryogenic mixed refrigerant water cooler WC-303 in the cryogenic mixed refrigerant compression cooling system.

[0058] Then, the hydrogen gas compressed and cooled by the hydrogen gas compression cooling system is 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. The separated gas phase and liquid phase pre-cooling mixed refrigerant is introduced into the first heat exchanger HEX1.

[0059] The liquid phase pre-cooling mixed refrigerant cooled by the first heat exchanger HEX1 is throttled by the first throttling valve VLV1. The throttled pre-cooling mixed refrigerant is introduced back into the first heat exchanger HEX1 as the refrigerant of the primary heat exchange system, and cools the hydrogen gas and the gas-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 rises after absorbing heat. The hydrogen gas cooled by the primary heat exchange system is introduced into the second heat exchanger HEX2.

[0060] The gas phase pre-cooling mixed refrigerant cooled by the primary heat exchange system is introduced into the third gas-liquid separator V3 in the secondary heat exchange system for gas-liquid separation. The separated gas phase and liquid phase pre-cooling mixed refrigerant is introduced into the second heat exchanger HEX2.

[0061] 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 into the second heat exchanger HEX2 as the refrigerant of the secondary heat exchange system, and the hydrogen gas and the gas-liquid two-phase pre-cooling mixed refrigerant in the second heat exchanger HEX2 are cooled. The pre-cooling mixed refrigerant as the refrigerant is heated after absorbing heat, and the hydrogen gas cooled by the secondary heat exchange system is introduced into the third heat exchanger HEX3.

[0062] The gas 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 is throttled by the third throttle valve VLV3. The pre-cooling mixed refrigerant after the throttling is introduced into the third heat exchanger HEX3 as the refrigerant of the tertiary heat exchange system, and the hydrogen gas in the third heat exchanger HEX3 is cooled. The pre-cooling mixed refrigerant as the refrigerant is heated after absorbing heat, and the hydrogen gas cooled by the third heat exchanger HEX3 is introduced into the fourth heat exchanger HEX4.

[0063] The pre-cooling mixed refrigerant after absorbing heat in the third heat exchanger HEX3 and the pre-cooling mixed refrigerant after being throttled by the second throttle valve VLV2 are introduced into the third mixer MIX-3 in the secondary heat exchange system to be mixed, and 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 gas and the pre-cooling mixed refrigerant in the secondary heat exchange system as the refrigerant, and is heated after absorbing heat.

[0064] The pre-cooling mixed refrigerant after absorbing heat in the second heat exchanger HEX2 and the pre-cooling mixed refrigerant after being throttled by the first throttle valve VLV1 are introduced into the second mixer MIX-2 in the primary heat exchange system to be mixed, and 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 gas and the pre-cooling mixed refrigerant in the primary heat exchange system as the refrigerant, and is heated after absorbing heat.

[0065] The pre-cooling mixed refrigerant after absorbing heat in the first heat exchanger HEX1 is introduced back into the pre-cooling mixed refrigerant compression cooling system to complete the closed loop circulation of the pre-cooling mixed refrigerant.

[0066] At the same time, the deep cooling mixed refrigerant compressed and cooled by the deep cooling mixed refrigerant compression cooling system is introduced into the fourth heat exchanger HEX-4 in the quaternary heat exchange system, and is cooled by the circulating backflow deep cooling mixed refrigerant.

[0067] The cryogenic mixed refrigerant cooled by the fourth heat exchanger HEX-4 is introduced into a first separator TEE-1 in the five-stage heat exchange system, a part of the cryogenic mixed refrigerant branched out is introduced into a fifth heat exchanger HEX5, another part of the cryogenic mixed refrigerant branched out is introduced into a first expander E-1 for expansion and temperature reduction, and the part of the cryogenic mixed refrigerant as the refrigerant of the five-stage heat exchange system is introduced into the fifth heat exchanger HEX5 after the expansion and temperature reduction, and cools the hydrogen and the cryogenic mixed refrigerant not subjected to the expansion and temperature reduction in the fifth heat exchanger HEX5, the part of the cryogenic mixed refrigerant as the refrigerant is raised in temperature after absorbing heat, and the hydrogen cooled by the fifth heat exchanger HEX5 is introduced into a sixth heat exchanger HEX6.

[0068] The cryogenic mixed refrigerant cooled by the fifth heat exchanger HEX-5 is introduced into a second separator TEE-2 in the six-stage heat exchange system, a part of the cryogenic mixed refrigerant branched out is introduced into a sixth heat exchanger HEX6, another part of the cryogenic mixed refrigerant branched out is introduced into a second expander E-2 for expansion and temperature reduction, and the part of 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 reduction, and cools the hydrogen and the cryogenic mixed refrigerant not subjected to the expansion and temperature reduction in the sixth heat exchanger HEX6, the part of the cryogenic mixed refrigerant as the refrigerant is raised in temperature after absorbing heat, and the hydrogen cooled by the sixth heat exchanger HEX6 is introduced into a seventh heat exchanger HEX7.

[0069] The cryogenic mixed refrigerant cooled by the sixth heat exchanger HEX-6 is introduced into a third expander E-3 in the seven-stage heat exchange system for expansion and temperature reduction, the part of the cryogenic mixed refrigerant as the refrigerant of the seven-stage heat exchange system is introduced into the seventh heat exchanger HEX7 after the expansion and temperature reduction, and cools the hydrogen in the seventh heat exchanger HEX7 to obtain low-temperature supercritical hydrogen, the part of the cryogenic mixed refrigerant as the refrigerant is raised in temperature after absorbing heat, and the obtained low-temperature supercritical hydrogen is introduced into a hydrogen storage tank CT and stored.

[0070] The cryogenic mixed refrigerant after absorbing heat in the seventh heat exchanger HEX7 is introduced into the sixth heat exchanger HEX6 of the six-stage heat exchange system, continues to cool the hydrogen and the cryogenic mixed refrigerant not subjected to the expansion and temperature reduction in the six-stage heat exchange system as the refrigerant, and is raised in temperature after absorbing heat.

[0071] The part of the cryogenic mixed refrigerant after absorbing the heat of the sixth heat exchanger HEX6 and the cryogenic mixed refrigerant after absorbing the heat introduced into the sixth heat exchanger HEX6 by the second expander E-2 is introduced into the fifth mixer MIX-5 in the six-stage heat exchange system for mixing, and the mixed cryogenic mixed refrigerant is introduced into the fifth heat exchanger HEX5 in the five-stage heat exchange system to continue to cool the hydrogen and the unexpanded and cooled cryogenic mixed refrigerant in the five-stage heat exchange system as the refrigerant and increase the temperature after absorbing the heat.

[0072] The part of the cryogenic mixed refrigerant after absorbing the heat of the fifth heat exchanger HEX5 and the cryogenic mixed refrigerant after absorbing the heat introduced into the fifth heat exchanger HEX5 by the first expander E-1 is introduced into the fourth mixer MIX-4 in the five-stage heat exchange system for mixing, and the mixed cryogenic mixed refrigerant is introduced into the fourth heat exchanger HEX4 in the four-stage heat exchange system to continue to cool the hydrogen and the unexpanded and cooled cryogenic mixed refrigerant in the four-stage heat exchange system as the refrigerant and increase the temperature after absorbing the heat.

[0073] The part of the cryogenic mixed refrigerant after absorbing the heat of the fourth heat exchanger HEX4 is introduced back into the cryogenic mixed refrigerant compression cooling system to complete the closed loop circulation of the cryogenic mixed refrigerant.

[0074] In the embodiment, the initial pressure of the 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 cryogenic mixed refrigerant can be set to obtain different total energy consumption, unit energy consumption, and energy consumption reduction percentage compared with the unit energy consumption of the traditional hydrogen liquefaction process, as shown in Table 1.

[0075] Table 1 Total energy consumption, unit energy consumption, and relative energy consumption reduction percentage of the system under different parameters

[0076]

[0077]

[0078] The parameter one can be set: in the pre-cooling mixed refrigerant, the molar component proportions of methane, ethane, propane, n-pentane, nitrogen and ethylene are 22.15%, 11.47%, 16.57%, 23.84%, 11.03% and 14.94% respectively, the pre-cooling mixed refrigerant molar flow is 78.44 kmol / h, in the deep cooling mixed refrigerant, the molar component proportions of hydrogen, neon and helium are 4.07%, 5.89% and 90.04% respectively, the deep cooling mixed refrigerant molar flow is 190.86 kmol / h, through simulation calculation, the total energy consumption of the low-temperature supercritical hydrogen storage system under the parameter is 6878 kW, the unit energy consumption is 6.878 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 44.98%-54.15%.

[0079] The parameter two can be set: in the pre-cooling mixed refrigerant, the molar component proportions of methane, ethane, propane, n-pentane, nitrogen and ethylene are 20.30%, 14.17%, 18.62%, 26.48%, 5.82% and 14.62% respectively, the pre-cooling mixed refrigerant molar flow is 64.40 kmol / h, in the deep cooling mixed refrigerant, the molar component proportions of hydrogen, neon and helium are 5.91%, 6.86% and 87.23% respectively, the deep cooling mixed refrigerant molar flow is 181.59 kmol / h, through simulation calculation, the total energy consumption of the low-temperature supercritical hydrogen storage system under the parameter is 6737 kW, the unit energy consumption is 6.737 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 46.10%-55.09%. Compared with the parameter one, the parameter two changes the mixed refrigerant component proportion, reduces the pre-cooling mixed refrigerant and the deep cooling mixed refrigerant molar flow, so that the system total energy consumption and unit energy consumption are reduced.

[0080] 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 20.53%, 5.95%, 18.06%, 22.50%, 7.31% and 23.65% respectively, the molar flow of the pre-cooling mixed refrigerant is 65.25 kmol / h, the molar component proportions of hydrogen, neon and helium in the deep cooling mixed refrigerant are 6.43%, 7.79% and 85.77% respectively, and the molar flow of the deep cooling mixed refrigerant is 175.80 kmol / h. Through simulation calculation, the total energy consumption of the low-temperature supercritical hydrogen storage system under the parameter three is 6696 kW, and the unit energy consumption is 6.696 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 46.43%-55.36%. Compared with the parameter one, the parameter two 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.

[0081] Therefore, the parameter three has better effect, and in actual situation, the parameter can also be set according to actual needs.

[0082] Effects of the embodiment

[0083] According to the low-temperature supercritical hydrogen storage system using two-stage series 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, a sixth heat exchange system, a seventh heat exchange system and a hydrogen storage tank, 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 using two-stage series mixed refrigerant refrigeration provided in the embodiment 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 a closed loop circulation in the system, the cooling of the hydrogen by the mixed refrigerant can be fully utilized, the production cost is reduced, and the cooling effect is improved.

[0084] Therefore, the low-temperature supercritical hydrogen storage system using two-stage series 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.

[0085] 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 cryogenic supercritical hydrogen storage system utilizing a two-stage series hybrid refrigerant, characterized by, The system comprises: a hydrogen compression cooling system for compressing and cooling hydrogen; a pre-cooling mixed refrigerant compression cooling system for compressing and cooling a pre-cooling mixed refrigerant; a deep cooling mixed refrigerant compression cooling system for compressing and cooling a deep cooling mixed refrigerant; a primary heat exchange system for splitting the cooled pre-cooling mixed refrigerant from the pre-cooling mixed refrigerant compression cooling system into gas-liquid two phases, and throttling the liquid phase pre-cooling mixed refrigerant to lower its temperature, the throttled pre-cooling mixed refrigerant being used to cool the gas-liquid two phase pre-cooling mixed refrigerant split in the primary heat exchange system and the hydrogen from the hydrogen compression cooling system; a secondary heat exchange system for splitting the cooled pre-cooling mixed refrigerant from the primary heat exchange system into gas-liquid two phases, and throttling the liquid phase pre-cooling mixed refrigerant to lower its temperature, the throttled pre-cooling mixed refrigerant being used to cool the gas-liquid two phase pre-cooling mixed refrigerant split in the secondary heat exchange system and the hydrogen from the primary heat exchange system, the pre-cooling mixed refrigerant after absorbing heat being returned to the primary heat exchange system to cool the hydrogen and the pre-cooling mixed refrigerant; a tertiary heat exchange system for throttling the cooled pre-cooling mixed refrigerant from the secondary heat exchange system, the throttled pre-cooling mixed refrigerant being used to cool the hydrogen and the pre-cooling mixed refrigerant from the secondary heat exchange system, the pre-cooling mixed refrigerant after absorbing heat being returned to the secondary heat exchange system to cool the hydrogen and the pre-cooling mixed refrigerant; a quaternary heat exchange system for cooling the hydrogen from the tertiary heat exchange system and the deep cooling mixed refrigerant from the deep cooling mixed refrigerant compression cooling system; a quinary heat exchange system for splitting the cooled deep cooling mixed refrigerant from the quaternary heat exchange system into two parts, and expanding one part of the deep cooling mixed refrigerant to lower its temperature, the expanded deep cooling mixed refrigerant being used to cool the other part of the deep cooling mixed refrigerant and the hydrogen from the quaternary heat exchange system, the part of the deep cooling mixed refrigerant after absorbing heat being returned to the quaternary heat exchange system to cool the hydrogen and the deep cooling mixed refrigerant; a senary heat exchange system for splitting the cooled deep cooling mixed refrigerant from the quinary heat exchange system into two parts, and expanding one part of the deep cooling mixed refrigerant to lower its temperature, the expanded deep cooling mixed refrigerant being used to cool the other part of the deep cooling mixed refrigerant and the hydrogen from the quinary heat exchange system, the part of the deep cooling mixed refrigerant after absorbing heat being returned to the quinary heat exchange system to cool the hydrogen and the deep cooling mixed refrigerant; a septenary heat exchange system for expanding the cooled deep cooling mixed refrigerant from the senary heat exchange system to lower its temperature, the expanded deep cooling mixed refrigerant being used to cool the hydrogen from the senary heat exchange system to obtain low-temperature supercritical hydrogen; and a hydrogen liquefier for liquefying the low-temperature supercritical hydrogen. a hydrogen storage tank for storing the low-temperature supercritical hydrogen from the seven-stage heat exchange system; wherein the hydrogen 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, the sixth-stage heat exchange system, the seventh-stage heat exchange system, and finally enters the hydrogen storage tank, the pre-cooling mixed refrigerant compression cooling system comprises a first pre-cooling mixed refrigerant compressor, a first pre-cooling mixed refrigerant water cooler, a first gas-liquid separator, a second pre-cooling mixed refrigerant compressor, a second pre-cooling mixed refrigerant water cooler, a pre-cooling mixed refrigerant pump, and a first mixer, the first pre-cooling mixed refrigerant compressor is configured to compress the pre-cooling mixed refrigerant, the first pre-cooling mixed refrigerant water cooler is configured to cool the pre-cooling mixed refrigerant compressed by the first pre-cooling mixed refrigerant compressor, the first gas-liquid separator is configured to separate the pre-cooling mixed refrigerant cooled by the first pre-cooling mixed refrigerant water cooler into gas-liquid two phases, the second pre-cooling mixed refrigerant compressor is configured to compress the gas-phase pre-cooling mixed refrigerant, the second pre-cooling mixed refrigerant water cooler is configured to cool the pre-cooling mixed refrigerant compressed by the second pre-cooling mixed refrigerant compressor, the pre-cooling mixed refrigerant pump is configured to compress the liquid-phase pre-cooling mixed refrigerant, the first mixer is configured to mix the pre-cooling mixed refrigerant cooled by the second pre-cooling mixed refrigerant water cooler and the pre-cooling mixed refrigerant compressed by the pre-cooling mixed refrigerant pump, the pre-cooling mixed refrigerant comprises methane, ethane, propane, n-pentane, nitrogen, and ethylene, the deep cooling mixed refrigerant comprises hydrogen, helium, and neon.

2. The low-temperature supercritical hydrogen storage system according to claim 1, wherein: wherein, 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 sequentially passes through the above devices in the hydrogen compression cooling system in sequence, and the hydrogen compressed and cooled by the hydrogen compression cooling system has a pressure 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 configured 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 configured to cool the hydrogen after each compression.

3. The low-temperature supercritical hydrogen storage system according to claim 1, wherein: wherein The deep cooling mixed refrigerant compression cooling system comprises 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 the deep cooling mixed refrigerant compression cooling system in sequence, 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, 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.

4. The cryogenic supercritical hydrogen storage system according to claim 1, wherein: wherein The primary heat exchange system comprises 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 throttled and cooled by the first throttling valve, The first heat exchanger is used for cooling the pre-cooling mixed refrigerant from the second gas-liquid separator and the hydrogen compressed and cooled in the hydrogen compression cooling system by using the pre-cooling mixed refrigerant throttled and cooled by the first throttling valve.

5. The cryogenic supercritical hydrogen storage system according to claim 4, wherein: wherein The secondary heat exchange system comprises 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 throttled and cooled by the second throttling valve, The second heat exchanger is used for cooling the pre-cooling mixed refrigerant from the third gas-liquid separator and the hydrogen cooled in the first heat exchanger by using the pre-cooling mixed refrigerant throttled and cooled by the second throttling valve.

6. The cryogenic supercritical hydrogen storage system according to claim 5, wherein: wherein The tertiary heat exchange system comprises 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, The third heat exchanger is used for cooling the hydrogen cooled in the second heat exchanger and the pre-cooling mixed refrigerant by using the pre-cooling mixed refrigerant throttled and cooled by the third throttling valve; The pre-cooling mixed refrigerant after absorbing heat in the third heat exchanger enters the third mixer and mixes with the pre-cooling mixed refrigerant from the second throttling valve, the pre-cooling mixed refrigerant after mixing in the third mixer cools the hydrogen gas passing through the second heat exchanger, enters the second mixer and mixes with the pre-cooling mixed refrigerant from the first throttling valve, the pre-cooling mixed refrigerant after mixing in the second mixer cools the hydrogen gas passing through the first heat exchanger, and then enters the pre-cooling mixed refrigerant compression cooling system, realizing the recycling of the pre-cooling mixed refrigerant.

7. The cryogenic supercritical hydrogen storage system of claim 1, wherein: wherein, the four-stage heat exchange system comprises a fourth heat exchanger, the fourth heat exchanger is configured to cool the hydrogen gas cooled by the three-stage heat exchange system and the deep cooling mixed refrigerant compressed and cooled by the deep cooling mixed refrigerant compression cooling system using the deep cooling mixed refrigerant; the five-stage heat exchange system comprises a first separator, a first expander, a fifth heat exchanger, and a fourth mixer, the first separator is configured to separate the deep cooling mixed refrigerant cooled by the fourth heat exchanger into the first expander and the fifth heat exchanger, the first expander is configured to expand and cool the deep cooling mixed refrigerant from the first separator, the fifth heat exchanger is configured to cool the hydrogen gas cooled in the fourth heat exchanger and the deep cooling mixed refrigerant not expanded and cooled from the first separator using the deep cooling mixed refrigerant expanded and cooled by the first expander, the fourth mixer is configured to receive the deep cooling mixed refrigerant after absorbing heat in the fifth heat exchanger.

8. The cryogenic supercritical hydrogen storage system of claim 7, wherein: wherein, the six-stage heat exchange system comprises a second separator, a second expander, a sixth heat exchanger, and a fifth mixer, the second separator is configured to separate the deep cooling mixed refrigerant cooled by the fifth heat exchanger into the second expander and the sixth heat exchanger, the second expander is configured to expand and cool the deep cooling mixed refrigerant from the second separator, the sixth heat exchanger is configured to cool the deep cooling mixed refrigerant not expanded and cooled from the second separator and the hydrogen gas cooled in the fifth heat exchanger using the deep cooling mixed refrigerant expanded and cooled by the second expander, the fifth mixer is configured to receive the deep cooling mixed refrigerant after absorbing heat in the sixth heat exchanger.

9. The cryogenic supercritical hydrogen storage system of claim 8, wherein: wherein the seven-stage heat exchange system comprises a third expander and a seventh heat exchanger, the third expander is configured to expand and cool the deep cooling mixed refrigerant cooled in the sixth heat exchanger, and the seventh heat exchanger is configured to cool the hydrogen gas cooled in the sixth heat exchanger using the deep cooling mixed refrigerant expanded and cooled by the third expander. The seventh heat exchanger is used for cooling the hydrogen cooled in the sixth heat exchanger by the deep cooling mixed refrigerant cooled by the third expander, to obtain the low-temperature supercritical hydrogen; After the deep cooling mixed refrigerant absorbs heat in the seventh heat exchanger, the deep cooling mixed refrigerant cools the hydrogen passed through the sixth heat exchanger, and then enters the fifth mixer to mix with the deep cooling mixed refrigerant from the second expander after absorbing heat, the deep cooling mixed refrigerant after mixing in the fifth mixer cools the hydrogen passed through the fifth heat exchanger, and then enters the fourth mixer to mix with the deep cooling mixed refrigerant from the first expander after absorbing heat, the deep cooling mixed refrigerant after mixing in the fourth mixer cools the hydrogen passed through the fourth heat exchanger, and then enters the deep cooling mixed refrigerant compression cooling system, to realize the recycling of the deep cooling mixed refrigerant.

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