Helium liquefied hydrogen device and method

Abstract

The present invention proposes a helium liquefied hydrogen device and method, wherein hydrogen passes through a first-stage heat exchanger and a mechanical low-temperature precooling cycle and a helium circulation precooling, undergoes positive-parallel conversion through the second, third, fourth and fifth heat exchangers, and exchanges heat with the cold helium coming out of the second turbine expander in the helium circulation, and enters the liquid hydrogen throttle valve for throttling, and the generated liquid hydrogen enters the liquid storage tank to complete the hydrogen liquefaction process. The present invention allows the helium entering and exiting the helium circulation cryogenic compressor unit to undergo mechanical low-temperature precooling, the helium is cryogenically compressed to reduce the compression work, and the turbine expander recovers the expansion work, thereby improving the thermodynamic efficiency of the system; the hydrogen liquefaction system only relies on the cold amount provided by the helium circulation system and the mechanical low-temperature precooling cycle, and can complete the liquefaction of hydrogen without compression, thereby improving the safety of the system; the helium circulation cryogenic compressor unit and the mechanical low-temperature compressor both use oil-free gas suspension centrifugal compressors, thereby avoiding the problems of oil removal and oil return, and the reliability is significantly improved.

Description

Technical Field

[0001] The present invention relates to the field of cryogenic refrigeration technology, and in particular to a helium liquefied hydrogen device and method. Background Art

[0002] The helium refrigeration hydrogen liquefaction cycle is an effective method for hydrogen liquefaction. The commonly used method is the Brayton cycle, which cools the helium to a temperature lower than the liquefaction temperature of hydrogen, and then cools and liquefies the hydrogen through a heat exchanger. In this process, in order to increase the liquefaction coefficient of the cycle, liquid nitrogen pre-cooling is usually used at the first heat exchanger. However, liquid nitrogen preparation usually uses gas separation technology, including compression, cooling, drying and separation. The preparation process is complicated and the liquefaction rate is low. If liquid nitrogen is not used for preparation, liquid nitrogen must be purchased separately. Liquid nitrogen is expensive. For large-scale industrial production, the use of liquid nitrogen pre-cooling will reduce the economy of the circulation system.

[0003] The compressor of the helium circulation system in the traditional helium refrigeration hydrogen liquefaction cycle usually uses room temperature compression. Because helium has a high adiabatic index and a small specific heat capacity, it is easy to generate higher compression heat during the room temperature compression process, causing a large compression temperature rise, consuming more compression work, resulting in reduced system efficiency and high unit energy consumption for hydrogen liquefaction. The compressor used in this system is usually a screw compressor. In order to ensure the stable and reliable operation of the screw compressor, it needs lubrication with lubricating oil. Therefore, the system requires precise oil removal and oil return equipment, which not only occupies a large area, but also if the oil removal is not precise enough, the prepared liquid hydrogen will be contaminated by the lubricating oil. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of low efficiency, poor economy and need for oil removal in the existing helium liquefied hydrogen system, and to provide a helium liquefied hydrogen device and method with low power consumption, economic energy saving and no oil pollution.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A helium liquefied hydrogen device, characterized in that it comprises a helium circulation system, a primary precooling system, a mechanical low-temperature precooling circulation system and a hydrogen liquefaction system; the primary precooling system provides precooling for the mechanical low-temperature precooling circulation system, the mechanical low-temperature precooling circulation system provides precooling for the hydrogen liquefaction system, and the helium circulation system provides cooling capacity for the hydrogen liquefaction process of the hydrogen liquefaction system; the helium liquefied hydrogen device comprises a helium circulation low-temperature compressor unit, a first low-temperature compressor, an intermediate heat exchanger, a second low-temperature compressor, an expansion pipeline throttle valve, a first A turbine expander, a second turbine expander, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a fifth heat exchanger, a second heat exchanger positive para-hydrogen conversion channel, a third heat exchanger positive para-hydrogen conversion channel, a fourth heat exchanger positive para-hydrogen conversion channel, a fifth heat exchanger positive para-hydrogen conversion channel, a first electromagnetic three-way valve, a liquid hydrogen throttle valve, a liquid hydrogen dewar, a liquid storage tank, a second electromagnetic three-way valve, a mechanical low-temperature compressor, an aftercooler, a third turbine expander, a regenerator, a sixth heat exchanger, a refrigeration compressor, a condenser, and a refrigeration throttle valve.

[0007] In some preferred embodiments, the process of the helium circulation system is that the high-pressure helium at the outlet of the helium circulation low-temperature compressor unit passes through the compression end of the first turbine expander and the compression end of the second turbine expander, then enters the expansion pipeline throttle valve for throttling, and then enters the expansion end of the first turbine expander and the expansion end of the second turbine expander for adiabatic expansion and refrigeration. The cold helium coming out of the expansion end of the second turbine expander passes through the fifth heat exchanger, the fourth heat exchanger, the third heat exchanger, the second heat exchanger and the first heat exchanger to cool the hydrogen, and then enters the helium circulation low-temperature compressor unit to complete the entire helium cycle.

[0008] In some preferred embodiments, the process of the primary precooling system is that the refrigeration compressor inhales low-temperature and low-pressure gaseous refrigerant from the sixth heat exchanger, isentropically compressed by the refrigeration compressor to become high-temperature and high-pressure superheated steam, and then enters the condenser for isobaric cooling to become supercooled liquid refrigerant. The liquid refrigerant is adiabatically throttled by the throttle valve to become a low-temperature and low-pressure two-phase refrigerant. The two-phase refrigerant absorbs the heat of the gas before entering the mechanical low-temperature compressor in the sixth heat exchanger to perform isobaric heat absorption and conversion into a gaseous refrigerant, completing the entire primary precooling.

[0009] In some preferred embodiments, the process of the mechanical low-temperature pre-cooling circulation system is that the high-pressure gas at the outlet of the mechanical low-temperature compressor enters the aftercooler for cooling, the cooled gas enters the compression end of the third turbine expander to increase the pressure, then enters the regenerator for heat exchange with the reflux gas, and then enters the expansion end of the third turbine expander for adiabatic expansion refrigeration, the low-temperature gas coming out of the expander enters the second electromagnetic three-way valve, the gas coming out of the first outlet of the second electromagnetic three-way valve is the helium of the helium circulation system and the hydrogen of the hydrogen liquefaction system, which are pre-cooled through the first heat exchanger, and the gas coming out of the second outlet of the second electromagnetic three-way valve is the helium circulation low-temperature compressor unit for heat exchange, the pre-cooled gas and the heat-exchanged gas are combined and then heat exchanged through the regenerator, and then cooled by the primary pre-cooling system through the sixth heat exchanger, and then enters the inlet of the mechanical low-temperature compressor to complete the entire mechanical low-temperature pre-cooling cycle.

[0010] In some preferred embodiments, the process of the hydrogen liquefaction system is that the hydrogen passes through the first-stage heat exchanger and is pre-cooled by a mechanical low-temperature pre-cooling cycle and a helium cycle, and then passes through the second heat exchanger positive para-hydrogen conversion channel, the third heat exchanger positive para-hydrogen conversion channel, the fourth heat exchanger positive para-hydrogen conversion channel and the fifth heat exchanger positive para-hydrogen conversion channel to fully exchange heat with the cold helium coming out of the second turbine expander in the helium cycle, and enters the liquid hydrogen throttle valve for throttling, and the liquid hydrogen produced after throttling enters the liquid hydrogen Dewar. After the liquid hydrogen Dewar stores a sufficient amount of liquid hydrogen, it can enter the liquid storage tank for storage, and the hydrogen produced again in the liquid hydrogen Dewar flows back to the first electromagnetic three-way valve between the fourth heat exchanger and the fifth heat exchanger for another cooling cycle, thereby completing the hydrogen liquefaction process.

[0011] Preferably, the hydrogen is purified hydrogen.

[0012] In some preferred embodiments, the helium circulation cryogenic compressor unit is an oil-free gas-suspended centrifugal compressor, which is supported by an air-suspended bearing or a magnetic hybrid bearing. Its compression is low-temperature compression. The helium circulation cryogenic compressor unit uses 1-4 centrifugal compressors in series to achieve 1-10 stages of compression. The compressor stages are pre-cooled by a mechanical low-temperature pre-cooling cycle. The compressor inlet temperature is between 10K and 250K, and the working fluid used is helium.

[0013] In some preferred embodiments, the mechanical low-temperature compressor is an oil-free air-suspended centrifugal compressor supported by air-suspended bearings or magnetic-gas hybrid bearings, and its compression is low-temperature compression, and the compressor inlet temperature is between 80K and 250K.

[0014] In some preferred embodiments, the helium circulation low-temperature compressor unit, the expansion pipeline throttle valve, the first turbine expander, the second turbine expander, the first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, the fifth heat exchanger, the second heat exchanger positive para-hydrogen conversion channel, the third heat exchanger positive para-hydrogen conversion channel, the fourth heat exchanger positive para-hydrogen conversion channel, the fifth heat exchanger positive para-hydrogen conversion channel, the first electromagnetic three-way valve, the liquid hydrogen throttle valve, the second electromagnetic three-way valve, the third turbine expander, the regenerator, the sixth heat exchanger, the refrigeration compressor, the condenser, and the refrigeration throttle valve are all arranged in a vacuum cold tank.

[0015] A helium liquefaction hydrogen method, characterized in that it includes a helium liquefaction hydrogen device, and the working fluid used in the mechanical low-temperature pre-cooling circulation system is air, nitrogen, neon, argon or helium.

[0016] In some preferred embodiments, the para-hydrogen conversion channel of the second heat exchanger, the para-hydrogen conversion channel of the third heat exchanger, the para-hydrogen conversion channel of the fourth heat exchanger and the para-hydrogen conversion channel of the fifth heat exchanger are all filled with para-hydrogen catalytic converter.

[0017] The advantages of the present invention using the above technical solution are:

[0018] (1) The present invention changes the traditional liquid nitrogen pre-cooling into mechanical low-temperature pre-cooling cycle pre-cooling, so that both parts of helium entering and leaving the helium circulation low-temperature compressor unit are pre-cooled by the mechanical low-temperature pre-cooling cycle. The low-temperature compression reduces the compression work by more than 70%, effectively improving the system efficiency.

[0019] (2) The present invention adopts a mechanical low-temperature precooling cycle to precool the helium circulation system and the hydrogen liquefaction system. The working fluid used in the mechanical low-temperature cycle is air, nitrogen, neon, argon or helium, which has the characteristics of being easy to obtain, cheap and pollution-free. In addition, a heat recovery cycle is adopted, which effectively reduces the compression work and expansion work, significantly reduces the irreversible loss, has good flexibility and high energy efficiency, and greatly improves the economy of the system.

[0020] (3) The hydrogen liquefaction system of the present invention relies only on the cooling capacity provided by the helium circulation system and the mechanical cryogenic circulation, and can complete the liquefaction of hydrogen without compression, thereby improving the safety of the system.

[0021] (4) The helium circulation cryogenic compressor unit and the mechanical cryogenic compressor in the present invention both adopt oil-free gas suspension centrifugal compressors, which have the advantages of being oil-free, having high heat transfer efficiency, being frictionless, having a long service life, having a high speed, having a compact structure, having a simple system, being stable and reliable in operation, and being energy-saving and efficient, thus avoiding the problem of requiring oil removal, and significantly improving reliability.

[0022] (5) The helium circulation cryogenic compressor unit described in the present invention uses two two-stage compression type centrifugal compressors connected in series to achieve four-stage compression. Mechanical low-temperature pre-cooling cycle pre-cooling is performed between the two compressors to keep the hydrogen at the inlet of the second compressor in a low-temperature state. Inter-stage cooling effectively reduces the compression heat, and low-temperature compression improves the thermodynamic performance of the system.

[0023] (6) The inlet of the mechanical low-temperature compressor of the present invention is precooled by a primary precooling system, and its compression is low-temperature compression, which further reduces the energy consumption of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flow chart of helium liquefied hydrogen with double-stage expansion recovery is provided for Example 1 of the present invention.

[0025] Figure 2 A flow chart of helium liquefaction and hydrogen recovery with single-stage expansion is provided for Example 2 of the present invention.

[0026] Figure 3 A flow chart of helium liquefied hydrogen with two-stage expansion recovery and a hydrogen compressor is provided for Example 3 of the present invention.

[0027] Figure 4 This is a flow chart of a mechanical low-temperature precooling cycle for precooling of a primary precooling system provided in an embodiment of the present invention.

[0028] Figure 5 The figure is a schematic diagram of the flow of a helium cycle cryogenic compressor unit provided in an embodiment of the present invention.

[0029] Figure 6 This is a schematic diagram of the flow of the helium cycle room temperature compressor unit.

[0030] In the figure above, the helium circulation system and the hydrogen liquefaction system 1, the helium circulation cryogenic compressor unit 4, the first cryogenic compressor 401, the intermediate heat exchanger 402, the second cryogenic compressor 403; the expansion pipeline throttle valve 101, the first turbine expander 102, the second turbine expander 103, the first heat exchanger 121, the second heat exchanger 122, the third heat exchanger 123, the fourth heat exchanger 124, the fifth heat exchanger 125, the second heat exchanger positive-para-hydrogen conversion channel 131, the third heat exchanger positive-para-hydrogen conversion channel 132, the fourth heat exchanger positive-para-hydrogen conversion channel 133, the fifth heat exchanger The heat device includes a positive-parahydrogen conversion channel 134, a first electromagnetic three-way valve 104, a liquid hydrogen throttle valve 105, a liquid hydrogen dewar 106, a liquid storage tank 107, a second electromagnetic three-way valve 108, a hydrogen compressor 109, a mechanical low-temperature compressor 201, an aftercooler 202, a third turbine expander 203, a regenerator 204, a sixth heat exchanger 205, a refrigeration compressor 206, a condenser 207, and a refrigeration throttle valve 208; a mechanical low-temperature circulation system 2, a hydrogen liquefaction normal temperature compressor unit 5, a first normal temperature compressor 501, an intermediate cooler 502, and a second normal temperature compressor 503. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] The helium liquefaction hydrogen process provided by the present invention with double-stage expansion recovery is shown in Figure 1 and Figure 4 , including a helium liquefaction circulation system and a hydrogen liquefaction system 1 and a mechanical low-temperature circulation system and a primary precooling system 2, and its working mode is as follows:

[0034] The process of the helium circulation system is as follows: the high-pressure helium at the outlet of the helium circulation low-temperature compressor unit 4 passes through the compression end of the first turbine expander 102 and the compression end of the second turbine expander 103, then enters the expansion pipeline throttle valve 101 for throttling, and then enters the expansion end of the first turbine expander 102 and the expansion end of the second turbine expander 103 for adiabatic expansion and refrigeration. The cold helium coming out of the expansion end of the second turbine expander 103 passes through the fifth heat exchanger 125, the fourth heat exchanger 124, the third heat exchanger 123, the second heat exchanger 122 and the first heat exchanger 121 to cool the hydrogen, and then enters the helium circulation low-temperature compressor unit 4 to complete the entire helium circulation.

[0035] The process of the primary precooling system is that the refrigeration compressor 206 inhales low-temperature and low-pressure gaseous refrigerant from the sixth heat exchanger 205, isentropically compressed by the refrigeration compressor 206 to become high-temperature and high-pressure superheated steam, and then enters the condenser 207 for isobaric cooling to become supercooled liquid refrigerant. The liquid refrigerant is adiabatically throttled by the throttle valve 208 to become a low-temperature and low-pressure two-phase refrigerant. The two-phase refrigerant absorbs the gas heat before entering the mechanical low-temperature compressor 201 in the sixth heat exchanger 205, and isobarically absorbs heat and is converted into a gaseous refrigerant to complete the entire primary precooling.

[0036] The process of the mechanical low-temperature precooling circulation system is as follows: the high-pressure gas at the outlet of the mechanical low-temperature compressor 201 enters the aftercooler 202 for cooling, the cooled gas enters the compression end of the third turbine expander 203 to increase the pressure, then enters the regenerator 204 for heat exchange with the reflux gas, and then enters the expansion end of the third turbine expander 203 for adiabatic expansion refrigeration, the low-temperature gas coming out of the expander 203 enters the second electromagnetic three-way valve 108, the gas coming out of the first outlet of the second electromagnetic three-way valve 108 is the helium of the helium circulation system and the hydrogen of the hydrogen liquefaction system, which are precooled through the first heat exchanger 121, and the gas coming out of the second outlet of the second electromagnetic three-way valve 108 is the helium circulation low-temperature compressor unit 4 for heat exchange, the precooled gas and the heat-exchanged gas are combined and then pass through the regenerator 204 for heat exchange, and then pass through the sixth heat exchanger 204 to be cooled by the primary precooling system, and then enter the inlet of the mechanical low-temperature compressor 201 to complete the entire mechanical low-temperature precooling cycle.

[0037] The process of the hydrogen liquefaction system is that the hydrogen passes through the first-stage heat exchanger 121 and is precooled by a mechanical low-temperature precooling cycle and a helium cycle, and then fully exchanges heat with the cold helium coming out of the second turbine expander 103 in the helium cycle through the second heat exchanger positive para-hydrogen conversion channel 131, the third heat exchanger positive para-hydrogen conversion channel 132, the fourth heat exchanger positive para-hydrogen conversion channel 133 and the fifth heat exchanger positive para-hydrogen conversion channel 134, and enters the liquid hydrogen throttle valve 104 for throttling. The liquid hydrogen generated after throttling enters the liquid hydrogen dewar 106, and the liquid hydrogen dewar 106 can enter the liquid storage tank 107 for storage after storing a sufficient amount of liquid hydrogen. The hydrogen generated again in the liquid hydrogen dewar 106 flows back to the first electromagnetic three-way valve 104 between the fourth heat exchanger 124 and the fifth heat exchanger 125 for cooling cycle again, thereby completing the hydrogen liquefaction process.

[0038] Example 2

[0039] The helium liquefaction hydrogen process provided by the present invention with single-stage expansion recovery is shown in Figure 2 and Figure 4 , including a helium liquefaction circulation system and a hydrogen liquefaction system 1 and a mechanical low-temperature circulation system and a primary precooling system 2, and its working mode is as follows:

[0040] The process of the helium circulation system is as follows: the high-pressure helium at the outlet of the helium circulation low-temperature compressor unit 4 passes through the compression end of the first turbine expander 102 and then enters the expansion pipeline throttle valve 101 for throttling, and then enters the expansion end of the first turbine expander 102 for adiabatic expansion and refrigeration. The cold helium coming out of the expansion end of the first turbine expander 102 passes through the fifth heat exchanger 125, the fourth heat exchanger 124, the second heat exchanger 122 and the first heat exchanger 121 to cool the hydrogen and then enters the helium circulation low-temperature compressor unit 4 to complete the entire helium cycle.

[0041] The process of the hydrogen liquefaction system is that the hydrogen passes through the first-stage heat exchanger 121 and is precooled by a mechanical low-temperature precooling cycle and a helium cycle, and then fully exchanges heat with the cold helium coming out of the first turbine expander 102 in the helium cycle through the second heat exchanger positive-parahydrogen conversion channel 131, the fourth heat exchanger positive-parahydrogen conversion channel 133 and the fifth heat exchanger positive-parahydrogen conversion channel 134, and enters the liquid hydrogen throttle valve 104 for throttling, and the liquid hydrogen generated after throttling enters the liquid hydrogen dewar 106, and the liquid hydrogen dewar 106 stores a sufficient amount of liquid hydrogen and can enter the liquid storage tank 107 for storage, and the hydrogen generated again in the liquid hydrogen dewar 106 flows back to the first electromagnetic three-way valve 104 between the fourth heat exchanger 124 and the fifth heat exchanger 125 for cooling cycle again, thereby completing the hydrogen liquefaction process.

[0042] The processes of the primary precooling system and the mechanical low-temperature precooling circulation system are the same as those in the first embodiment and will not be described in detail.

[0043] Example 3

[0044] The two-stage expansion recovery helium liquefied hydrogen process with hydrogen compressor provided by the present invention can be found in Figure 3 and Figure 4 , including a helium liquefaction circulation system and a hydrogen liquefaction system 1 and a mechanical low-temperature circulation system and a primary precooling system 2, and its working mode is as follows:

[0045] The process of the hydrogen liquefaction system is as follows: hydrogen is compressed by the hydrogen compressor 109 and then precooled by a mechanical low-temperature precooling cycle and a helium cycle in the first-stage heat exchanger 121, and then fully heat-exchanged with the cold helium coming out of the first turbine expander 102 in the helium cycle through the second heat exchanger positive-parahydrogen conversion channel 131, the fourth heat exchanger positive-parahydrogen conversion channel 133 and the fifth heat exchanger positive-parahydrogen conversion channel 134, and enters the liquid hydrogen throttle valve 104 for throttling. The liquid hydrogen generated after throttling enters the liquid hydrogen dewar 106, and the liquid hydrogen dewar 106 can enter the liquid storage tank 107 for storage after storing a sufficient amount of liquid hydrogen. The hydrogen generated again in the liquid hydrogen dewar 106 flows back to the first electromagnetic three-way valve 104 between the fourth heat exchanger 124 and the fifth heat exchanger 125 for cooling cycle again, thereby completing the hydrogen liquefaction process.

[0046] The processes of the helium circulation system, the primary precooling system and the mechanical low-temperature precooling circulation system are the same as those in the first embodiment and will not be described in detail.

[0047] The helium cycle cryogenic compressor unit provided by the present invention can be found in Figure 2 , including a first low-temperature compressor 401, an intermediate heat exchanger 402, and a second low-temperature compressor 403, and its working method is as follows:

[0048] The low-temperature helium at 80K or 120K enters the first low-temperature compressor 401 for two-stage compression, and then passes through the intermediate heat exchanger 402 for mechanical low-temperature circulation pre-cooling. After that, the helium is cooled to 80K or 120K again and enters the second low-temperature compressor 403 for two-stage compression; the helium circulation low-temperature compressor unit 4 adopts two two-stage compression type centrifugal compressors connected in series to achieve four-stage compression, and intermediate cooling and mechanical low-temperature circulation pre-cooling are performed between the two compressors.

[0049] As a comparison with the helium cycle low temperature compressor unit provided by the present invention, please refer to the helium cycle normal temperature compressor unit Figure 3 , including a first normal temperature compressor 501, an intercooler 502, and a second normal temperature compressor 503, and its working mode is as follows:

[0050] The 300K normal temperature helium enters the first normal temperature compressor 501 for two-stage compression, and then is cooled by the intermediate cooler 502. After that, the helium is cooled to 300K again and enters the second normal temperature compressor 503 for two-stage compression. The helium liquefaction normal temperature compressor unit 5 uses two two-stage compression type centrifugal compressors connected in series to achieve four-stage compression, and intermediate cooling is performed between the two compressors.

[0051] At the same compressor efficiency, pressure ratio, and helium mass flow rate, the comparison between normal temperature compression and low temperature compression is as follows:

[0052] Among them, the efficiency of the compressor is 75%, the suction pressure of the first compressor is 1.05bar, the pressure ratio of the first compressor is 3.38, the pressure ratio of the second compressor is 3.38, the total pressure ratio is 12, and the helium mass flow rate is 0.1kg / s:

[0053] (1) When using normal temperature compression and intermediate cooling measures, the inlet temperature of the first compressor is 300K, and the temperature of the helium after intermediate cooling is 300K. The calculation results are:

[0054] The power of the first compressor is 130.48 kW, the power of the second compressor is 130.74 kW, and the total power is 261.22 kW.

[0055] (2) When low-temperature compression and intermediate cooling are used, the inlet temperature of the first compressor is 80K, and the temperature of the helium after intermediate heat exchange is 80K. The calculation results are:

[0056] The power of the first compressor is 34.87kW, the power of the second compressor is 35.11kW, and the total power is 69.98kW.

[0057] (3) When low-temperature compression and intermediate cooling are used, the inlet temperature of the first compressor is 120K, and the temperature of the helium after intermediate heat exchange is 120K. The calculation results are:

[0058] The power of the first compressor is 52.25kW, the power of the second compressor is 52.51kW, and the total power is 104.76kW.

[0059] From the above calculation results, we can conclude that:

[0060] Compared with the intermediate cooling measures for compression at room temperature, the compression work of 80K low-temperature compression is reduced by 73.21% compared with the compression work of 300K room-temperature compression, and the compression work of 120K low-temperature compression is reduced by 59.9% compared with the compression work of 300K room-temperature compression; the reduction effect is obvious.

[0061] The present invention provides a helium liquefied hydrogen device and method, which replaces the traditional liquid nitrogen precooling with mechanical low-temperature precooling cycle precooling, so that the two parts of helium entering and exiting the helium circulation low-temperature compressor unit are precooled by the mechanical low-temperature precooling cycle, and the low-temperature compression reduces the compression work by more than 70%, effectively improving the system efficiency; the mechanical low-temperature precooling cycle is used to precool the helium circulation system and the hydrogen liquefaction system, and the working fluid used in the mechanical low-temperature cycle is air, nitrogen, neon, argon or helium, which has the characteristics of being easy to obtain, cheap and pollution-free, and adopts a heat recovery cycle, so that the compression work and expansion work are effectively reduced, the irreversible loss is significantly reduced, the flexibility is good, the energy efficiency is high, and the economy of the system is greatly improved; the hydrogen liquefaction system only relies on the cooling capacity provided by the helium circulation system and the mechanical low-temperature cycle, and can complete the hydrogen liquefaction without compression. Liquefaction improves the safety of the system; both the helium cycle cryogenic compressor unit and the mechanical cryogenic compressor use oil-free gas suspension centrifugal compressors, which have the advantages of oil-free, high heat transfer efficiency, no friction, long service life, high speed, compact structure, simple system, stable and reliable operation, energy saving and high efficiency, etc., avoiding the problem of oil removal, and reliability will be significantly improved; the helium cycle cryogenic compressor unit uses two two-stage compression type centrifugal compressors in series to achieve four-stage compression, and mechanical low-temperature pre-cooling cycle pre-cooling is performed between the two compressors to keep the hydrogen at the inlet of the second compressor in a low-temperature state. Interstage cooling effectively reduces the compression heat, and low-temperature compression improves the thermodynamic performance of the system; the inlet of the mechanical cryogenic compressor is pre-cooled by a primary pre-cooling system, and its compression is low-temperature compression, which further reduces the energy consumption of the system.

[0062] Of course, the helium liquefaction hydrogen device and method of the present invention may also have a variety of changes and modifications, and are not limited to the specific structure of the above-mentioned embodiment. In short, the protection scope of the present invention should include those changes or substitutions and modifications that are obvious to those of ordinary skill in the art.

Claims

1. A helium liquefied hydrogen device, characterized in that: It includes a helium circulation system, a primary precooling system, a mechanical low-temperature precooling circulation system and a hydrogen liquefaction system; The primary precooling system provides precooling for the mechanical low-temperature precooling circulation system, the mechanical low-temperature precooling circulation system provides precooling for the hydrogen liquefaction system, and the helium circulation system provides cooling capacity for the hydrogen liquefaction process of the hydrogen liquefaction system; The helium liquefied hydrogen device comprises a helium circulation cryogenic compressor unit, a first cryogenic compressor, an intermediate heat exchanger, a second cryogenic compressor, an expansion pipeline throttle valve, a first turbine expander, a second turbine expander, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a fifth heat exchanger, a second heat exchanger normal-parahydrogen conversion channel, a third heat exchanger normal-parahydrogen conversion channel, a fourth heat exchanger normal-parahydrogen conversion channel, a fifth heat exchanger normal-parahydrogen conversion channel, a first electromagnetic three-way valve, a liquid hydrogen throttle valve, a liquid hydrogen dewar, a liquid storage tank, a second electromagnetic three-way valve, a mechanical cryogenic compressor, an aftercooler, a third turbine expander, a regenerator, a sixth heat exchanger, a refrigeration compressor, a condenser, and a refrigeration throttle valve; The process of the mechanical low-temperature precooling circulation system is as follows: the high-pressure gas at the outlet of the mechanical low-temperature compressor enters the aftercooler for cooling, the cooled gas enters the compression end of the third turbine expander to increase the pressure, then enters the regenerator for heat exchange with the reflux gas, and then enters the expansion end of the third turbine expander for adiabatic expansion refrigeration, the low-temperature gas coming out of the expander enters the second electromagnetic three-way valve, the gas coming out of the first outlet of the second electromagnetic three-way valve is the helium of the helium circulation system and the hydrogen of the hydrogen liquefaction system, which are precooled through the first heat exchanger, and the gas coming out of the second outlet of the second electromagnetic three-way valve is the helium circulation low-temperature compressor unit for heat exchange, the precooled gas and the heat-exchanged gas are combined and then heat exchanged through the regenerator, and then cooled by the primary precooling system through the sixth heat exchanger, and then enters the inlet of the mechanical low-temperature compressor to complete the entire mechanical low-temperature precooling cycle.

2. A helium liquefied hydrogen device as claimed in claim 1, characterized in that: The process of the helium circulation system is as follows: the high-pressure helium at the outlet of the helium circulation low-temperature compressor unit passes through the compression end of the first turbine expander and the compression end of the second turbine expander, then enters the expansion pipeline throttle valve for throttling, and then enters the expansion end of the first turbine expander and the expansion end of the second turbine expander for adiabatic expansion and refrigeration. The cold helium coming out of the expansion end of the second turbine expander passes through the fifth heat exchanger, the fourth heat exchanger, the third heat exchanger, the second heat exchanger and the first heat exchanger to cool the hydrogen, and then enters the helium circulation low-temperature compressor unit to complete the entire helium circulation.

3. A helium liquefied hydrogen device as claimed in claim 1, characterized in that: The process of the primary precooling system is that the refrigeration compressor inhales low-temperature and low-pressure gaseous refrigerant from the sixth heat exchanger, isentropically compressed by the refrigeration compressor to become high-temperature and high-pressure superheated steam, and then enters the condenser for isobaric cooling to become supercooled liquid refrigerant. The liquid refrigerant is adiabatically throttled by the throttle valve to become a low-temperature and low-pressure two-phase refrigerant. The two-phase refrigerant absorbs the heat of the gas before entering the mechanical low-temperature compressor in the sixth heat exchanger to perform isobaric heat absorption and conversion into a gaseous refrigerant, completing the entire primary precooling.

4. A helium liquefied hydrogen device as claimed in claim 1, characterized in that: The process of the hydrogen liquefaction system is that hydrogen is precooled by a mechanical low-temperature precooling cycle and a helium cycle through a first-stage heat exchanger, and then fully heat-exchanged with the cold helium coming out of the second turbine expander in the helium cycle through the second heat exchanger positive para-hydrogen conversion channel, the third heat exchanger positive para-hydrogen conversion channel, the fourth heat exchanger positive para-hydrogen conversion channel and the fifth heat exchanger positive para-hydrogen conversion channel, and the liquid hydrogen generated after throttling by the liquid hydrogen throttle valve enters the liquid hydrogen dewar, the liquid hydrogen is stored in the liquid hydrogen dewar and then enters the liquid storage tank for storage, and the hydrogen generated again in the liquid hydrogen dewar flows back to the first electromagnetic three-way valve between the fourth heat exchanger and the fifth heat exchanger for another cooling cycle, thereby completing the hydrogen liquefaction process.

5. A helium liquefied hydrogen device as claimed in claim 1, characterized in that: The helium circulation cryogenic compressor unit is an oil-free gas suspension centrifugal compressor, which is supported by gas suspension bearings or magnetic hybrid bearings. Its compression is low-temperature compression. The helium circulation cryogenic compressor unit uses 1-4 centrifugal compressors in series to achieve 1-10 levels of compression. The compressor stages are pre-cooled by a mechanical low-temperature pre-cooling cycle. The compressor inlet temperature is between 10K and 250K, and the working fluid used is helium.

6. A helium liquefied hydrogen device as claimed in claim 1, characterized in that: The mechanical low-temperature compressor is an oil-free gas suspension centrifugal compressor, which is supported by gas suspension bearings or magnetic mixed bearings. Its compression is low-temperature compression, and the compressor inlet temperature is between 80K and 250K.

7. A helium liquefied hydrogen device as claimed in claim 1, characterized in that: The helium circulation cryogenic compressor unit, the expansion pipeline throttle valve, the first turbine expander, the second turbine expander, the first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger, the fifth heat exchanger, the second heat exchanger normal-parahydrogen conversion channel, the third heat exchanger normal-parahydrogen conversion channel, the fourth heat exchanger normal-parahydrogen conversion channel, the fifth heat exchanger normal-parahydrogen conversion channel, the first electromagnetic three-way valve, the liquid hydrogen throttle valve, the second electromagnetic three-way valve, the third turbine expander, the regenerator, the sixth heat exchanger, the refrigeration compressor, the condenser, and the refrigeration throttle valve are all arranged in a vacuum cold tank.

8. A method for liquefying hydrogen from helium, characterized in that: It comprises a helium liquefied hydrogen device according to any one of claims 1 to 7, wherein the working fluid used in the mechanical low-temperature pre-cooling circulation system is air, nitrogen, neon, argon or helium.

9. A helium liquefaction hydrogen method as claimed in claim 8, characterized in that: The normal-para-hydrogen conversion channel of the second heat exchanger, the normal-para-hydrogen conversion channel of the third heat exchanger, the normal-para-hydrogen conversion channel of the fourth heat exchanger and the normal-para-hydrogen conversion channel of the fifth heat exchanger are all filled with normal-para-hydrogen catalytic converter.

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