Water electrolysis and low-temperature liquefaction systems

Abstract

In one aspect, a system includes a water stream in fluid communication with an electrolyzer, the electrolyzer including an anode chamber and a cathode chamber, a deep-space oxygen radiator in fluid communication with the anode chamber of the electrolyzer, a low-temperature heat exchanger including an oxygen storage tank in fluid communication with the deep-space oxygen radiator, an electrochemical hydrogen compressor in fluid communication with the cathode chamber, and a hydrogen storage tank in fluid communication with the electrochemical hydrogen compressor via the cooled hydrogen stream, wherein at least a portion of the cooled hydrogen stream is in first fluid communication with the expansion valve and the low-temperature heat exchanger, the hydrogen storage tank is in second fluid communication with the electrochemical hydrogen compressor via the warmed hydrogen stream, and the low-temperature heat exchanger is in fluid communication with the warmed hydrogen stream.

Description

[Technical Field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 62 / 984,293, filed March 2, 2020. The related applications are incorporated herein by reference in their entireties. [Background technology]

[0002] A very interesting emerging topic is the development of a system capable of producing liquid hydrogen and oxygen from water. This system, scalable to tens of tons per month and capable of operating without human involvement, could be used both on the lunar surface and in space. For example, recent statements from the National Space Council indicate that humans could return to the lunar surface as early as 2024. However, one of the key requirements of this initiative is to enable a sustainable exploration program. Sustainability is achieved in part by using local resources whenever possible. Current plans for in-situ resource utilization (ISRU) on the Moon focus on water ice estimated to reside in permanently shadowed craters in the polar regions. If this ice could be accessed and processed, most of the consumables needed for further exploration could be supplied locally rather than transported from Earth. Water and its oxygen and hydrogen components could be used for a variety of space applications, including drinking and cooling water, breathing oxygen, fuel cell reactants, and liquid oxygen and hydrogen, especially for rocket propellants. The application of propellants is particularly attractive because propellants typically constitute the majority of the liftoff mass of spacecraft and rockets, and liquid oxygen and liquid hydrogen form a particularly good chemical propellant combination that is practical to use. A lunar liquid oxygen and liquid hydrogen refueling station could enable refueling of the ascent and descent stages, a feature necessary for reuse.

[0003] While hydrogen and oxygen liquefaction systems have been in use on Earth for over 100 years, the local environment near the lunar poles makes these systems impractical for use in space. Therefore, a system is needed that can produce hydrogen and oxygen from water with little or no human intervention, and liquefy them for use as propellants on the lunar surface. Summary of the Invention

[0004] A water electrolysis and low-temperature liquefaction system is disclosed herein.

[0005] In one aspect, a water electrolysis and cryogenic hydrogen liquefaction system includes a water stream in fluid communication with an anode chamber of an electrolyzer, the electrolyzer including an anode chamber, a cathode chamber, an electrolyzer membrane and electrode assembly disposed between the anode chamber and the cathode chamber, a deep space oxygen radiator in fluid communication with the anode chamber of the electrolyzer via a separated oxygen stream, a cryogenic heat exchanger including an oxygen storage tank in fluid communication with the deep space oxygen radiator via the cooled oxygen stream, an electrochemical hydrogen compressor in fluid communication with the cathode chamber via a separated hydrogen stream, and a hydrogen storage tank in fluid communication with the electrochemical hydrogen compressor via a cooled hydrogen stream cooled by at least one recuperative heat exchanger and the at least one deep space hydrogen radiator. At least a portion of the cooled hydrogen stream is in first fluid communication with an expansion valve and a low-temperature heat exchanger located downstream of the expansion valve, the hydrogen storage tank is in second fluid communication with the electrochemical hydrogen compressor via a warmed hydrogen stream warmed by at least one recuperative heat exchanger, and the low-temperature heat exchanger is in fluid communication with the warmed hydrogen stream via the heat-exchanged hydrogen stream.

[0006] In another aspect, a method for electrolyzing water and forming liquid oxygen therefrom at low temperatures includes: directing a water stream to at least one of an anode chamber and a cathode chamber of an electrolyzer (the electrolyzer including an anode chamber, a cathode chamber, and an electrolyzer membrane and electrode assembly located between the anode chamber and the cathode chamber); directing a separated oxygen stream from the anode chamber of the electrolyzer to a deep space oxygen radiator; directing the cooled oxygen stream from the deep space oxygen radiator to an oxygen storage tank of a cryogenic heat exchanger; and directing a separated hydrogen stream from the cathode chamber to an electrochemical hydrogen compressor. and routing the cooled hydrogen stream from the electrochemical hydrogen compressor to a hydrogen storage tank, cooling the cooled hydrogen stream with at least one recuperative heat exchanger and at least one deep space hydrogen radiator upstream of the hydrogen storage tank; expanding at least a portion of the cooled hydrogen stream with an expansion valve to form a refrigerant hydrogen stream and routing the refrigerant hydrogen stream to a low-temperature heat exchanger; routing the warmed hydrogen stream from the hydrogen storage tank to the electrochemical hydrogen compressor, warming the warmed hydrogen stream through the at least one recuperative heat exchanger; and routing the heat-exchanged hydrogen stream from the low-temperature heat exchanger to the warmed hydrogen stream upstream of the electrochemical hydrogen compressor.

[0007] These and other features are exemplified by the following figures, detailed description and claims. [Brief explanation of the drawings]

[0008] The following figures are exemplary embodiments provided to explain the present disclosure. [Figure 1] FIG. 1 is a diagram of one embodiment of a water electrolysis and low-temperature liquefaction system. [Figure 2] FIG. 2 is a diagram of one embodiment of the electrochemical portion of a water electrolysis and low-temperature liquefaction system. DETAILED DESCRIPTION OF THE INVENTION

[0009] Systems and methods for producing liquid oxygen from water that can be used on the Moon are desirable. While many processes for hydrogen production are available on Earth, each has significant drawbacks for use on the Moon. For example, steam methane reformation and coal gasification require hydrocarbon feedstocks. Biological processes, such as biomass production by microorganisms or algae, are too complex for small-scale lunar applications. Furthermore, direct solar water splitting, while promising, is too low-level to be practical for early lunar exploration.

[0010] To address these challenges, a water electrolysis and low-temperature hydrogen liquefaction system has been developed that electrolyzes water to produce oxygen and hydrogen, and then uses the hydrogen as a refrigerant to cryogenically liquefy the oxygen. Specifically, the system includes an electrolyzer that produces oxygen and hydrogen from water. The hydrogen is sent to an electrochemical compressor that not only increases the pressure of the hydrogen stream but also provides the refrigeration capacity necessary to liquefy both the oxygen and hydrogen product streams. A system of expansion valves and heat exchangers is configured to enable the hydrogen to be used as a refrigerant to liquefy the oxygen.

[0011] While several options exist for compressing hydrogen, including piston and turbomechanical compressors, adsorption compressors, and electrochemical compressors, electrochemical compression offers many advantages due to its simplicity, reliability, scalability, and efficiency. Electrochemical hydrogen compressors can compress hydrogen produced in electrolyzers and hydrogen recycled through the system from pressures of, for example, 1 bar to 100 bar. Advantageously, this compression can be performed without traditional mechanical means utilizing moving parts, which can be noisy and vibrating, can introduce contaminants from improper service and maintenance, and can be inefficient. The specific energy of electrochemical compression of hydrogen is comparable to commercially available compressors, with the added benefit of essentially eliminating the need for routine maintenance or downtime.

[0012] The system offers several distinct advantages over current systems, including being quieter and more efficient than mechanical compression and not requiring high-speed turbomachinery, pistons with clearance seals, lubrication, or vibration reduction techniques. The electrolyzer and compressor can use direct current, reducing electrical integration losses with the solar cells. These cumulative advantages are expected to result in long-term operation without the need for human intervention and reduced maintenance.

[0013] This system is uniquely suited for terrestrial applications and can be used in space, for example, by utilizing water harvested from the lunar surface and / or solar power generation systems deployed on the moon. Furthermore, the local thermal environment can be used to pre-cool the propellant, minimizing the power requirements. For example, the system can use a novel deep-space radiator to pre-cool the product stream to low temperatures and a Joule-Thomson (JT) liquefaction cycle to liquefy oxygen using hydrogen as a refrigerant. This system and method have the advantage of producing oxygen and hydrogen propellants, enabling the launch of vehicles from the lunar surface.

[0014] FIG. 1 is a diagram illustrating a water electrolysis and low-temperature liquefaction system and method using a chemical process to produce hydrogen and oxygen from water and a thermodynamic process to cryogenically liquefy the oxygen. In the chemical process portion of the system, a water stream 8 can be introduced into an electrolyzer 10. There, the water stream 8 can be separated into a separated oxygen stream 12 and a separated hydrogen stream 16, which can be sent to an electrochemical hydrogen compressor 40. The electrochemical hydrogen compressor 40 can compress the separated hydrogen stream 16 to form a compressed hydrogen stream 42. The electrolyzer 10 can optionally include one or more electrolyzers. Similarly, the electrochemical hydrogen compressor 40 can optionally include one or more electrochemical compressors. The temperature of the compressed hydrogen stream 42 can be 250-400 Kelvin (K), or 250-350 K, and the pressure of the compressed hydrogen stream 42 can be 50 bar (bar) or more, or 50-200 bar, or 100-200 bar.

[0015] In the thermodynamic process portion of the system, oxygen is cryogenically liquefied using hydrogen as a refrigerant. A portion of the separated oxygen stream 12 is then introduced into a deep space radiator 20, where it can be cooled by rejecting heat to the ambient environment. The temperature of the separated oxygen stream 12 can be 200-400 K, or 250-350 K. The pressure of the separated oxygen stream 12 can be 10-50 bar, or 20-40 bar. The temperature of the oxygen downstream of the deep space radiator, e.g., the cooled oxygen stream 22, can be 100-200 K, or 100-175 K. The pressure of the cooled oxygen stream 22 can be 10-50 bar, or 20-40 bar. The pressures of the separated oxygen stream 12 and the cooled oxygen stream 22 can be the same, or the streams can experience a pressure drop through the deep space radiator 20 such that the cooled oxygen stream 22 has a lower pressure than the separated oxygen stream 12. The deep space oxygen radiator 20 can have at least one of a high-emissivity thermal coating and a sun shield to protect against incident solar radiation. The deep space radiator can provide controlled pre-cooling to temperatures below 150 K, or below 100 K. The deep space oxygen radiator 20 can have a heat exchange surface area of ​​0.5 square meters or less, or 0.05 to 0.3 square meters or less. A portion of the oxygen flow 12 can be diverted around the deep space oxygen radiator 20 as a bypass flow 14. The amount diverted relative to the relative amount of the separated oxygen flow 12 introduced into the deep space oxygen radiator 20 can be optimized to achieve a desired temperature of the cooled oxygen flow 22.

[0016] The cooled oxygen stream 22 is expanded to a low pressure and sent to the oxygen storage tank 30, where a refrigerant hydrogen stream 74 may be used to liquefy the cooled oxygen stream 22 by removing the heat of vaporization to form liquid oxygen. An oxygen expansion valve 28 (used in addition to or instead of a Joule-Thomson device) may be located upstream of the oxygen storage tank 30. The oxygen expansion valve 28 may reduce the pressure of the cooled oxygen stream 22 via an isentropic process to a pressure below 10 bar, or between 0.005 and 5 bar, or between 0.05 and 0.5 bar. This pressure is merely exemplary and may depend on the desired storage pressure.

[0017] The tubes may be integrated with the oxygen storage tank 30 to form a cryogenic heat exchanger. The tubes may be configured to remove the heat of vaporization of the cooled oxygen stream 22. The temperature of the oxygen in the oxygen storage tank 30 may be, but is not limited to, 100 K or less, or between 45 and 100 K. The volume of the oxygen storage tank 30 may be, but is not limited to, 25 to 150 liters, or between 50 and 100 liters. Oxygen may be supplied from the oxygen storage tank via a tank vent valve 32. A portion of the stored oxygen in the oxygen storage tank 30 may be withdrawn as a liquid drain 34 for oxygen removal as needed. Other typical storage tank components, such as a relief valve, drain and service lines, and instrumentation, are not shown.

[0018] Referring back to the hydrogen portion of the thermodynamic process section of the system, the compressed hydrogen stream 42 exiting the electrochemical hydrogen compressor 40 may be introduced into one or more recuperative heat exchangers or one or more hydrogen radiators to be pre-cooled, for example, before being sent to a low-temperature heat exchanger via the hydrogen expansion valve 38 or to a hydrogen storage tank 90 via the hydrogen storage expansion valve 88. For example, the compressed hydrogen stream 42 may be introduced into a first recuperative heat exchanger 50 to exchange heat with a low-pressure hydrogen stream to form a first reduced-temperature hydrogen stream 52. The first recuperative heat exchanger 50 may exchange 150-250 watts. The temperature of the first reduced-temperature hydrogen stream 52 may be 150-350 K, or 160-240 K.

[0019] The first reduced temperature hydrogen stream 52 may be routed to a deep space hydrogen radiator 60 to form a radiator-cooled hydrogen stream 62. Similar to the deep space oxygen radiator 20, the deep space hydrogen radiator 60 may have at least one of a high-emissivity coating or a sun shield. The deep space hydrogen radiator 60 may have a heat exchange surface area of ​​0.5 to 5 square meters. The deep space hydrogen radiator 60 may provide controlled pre-cooling to temperatures below 180K, below 150K, or between 120 and 180K.

[0020] The radiator-cooled hydrogen stream 62 may be introduced into a second recuperative heat exchanger 70 to form a further reducing-temperature hydrogen stream 72. The second recuperative heat exchanger 70 may exchange 50-150 watts. The temperature of the further reducing-temperature hydrogen stream 72 may be between 50-100K, or between 55-80K.

[0021] A first portion of the further reduced temperature hydrogen stream 72 may be introduced into the hydrogen expansion valve 38 to reduce its pressure to form a refrigerant hydrogen stream 74 for cooling the oxygen storage tank 30. The refrigerant hydrogen stream 74 may have a pressure of 10 bar or less, or between 0.005 and 5 bar, or between 0.05 and 0.5 bar. The refrigerant hydrogen stream 74 may have a temperature of 100 K or less, or between 20 and 100 K.

[0022] The refrigerant hydrogen stream 74 may be sent to a cryogenic heat exchanger and used to cool the oxygen in the oxygen storage tank 30. The cryogenic heat exchanger may be a tube-on-tank heat exchanger in which the refrigerant hydrogen stream 74 may be wrapped around the oxygen storage tank 30. The heat-exchanged hydrogen stream 76 may have an elevated temperature compared to the refrigerant hydrogen stream 74. The temperature of the heat-exchanged hydrogen stream 76 may be between 90 and 250 K, or between 100 and 200 K.

[0023] A second portion of the further reduction-temperature hydrogen stream 72 may be introduced into a third recuperative heat exchanger 80 to form a final reduction-temperature hydrogen stream 82. The third recuperative heat exchanger 80 may exchange 10 to 50 watts. The temperature of the final reduction-temperature hydrogen stream 82 may be 20 to 80 K, or 20 to 45 K. The pressure of the final reduction-temperature hydrogen stream 82 may be 50 bar or more, or 50 to 200 bar, or 100 to 200 bar. The pressure of the final reduction-temperature hydrogen stream 82 may be the same as the pressure of the compressed hydrogen stream 42, or the final reduction-temperature hydrogen stream 82 may experience a pressure drop through a heat exchanger / radiator and have a lower pressure after each cooling event.

[0024] It should be noted that each recuperative heat exchanger can independently include one or more tube-in-tube, expanded foam, perforated-plate, or plate-fin heat exchangers. Additionally, each recuperative heat exchanger can include one or more recuperative heat exchangers arranged in series or parallel.

[0025] The final reduction-temperature hydrogen stream 82 may be sent to a hydrogen storage tank 90. ​​A hydrogen storage expansion valve 88 may be disposed upstream of the hydrogen storage tank 90. ​​The hydrogen storage expansion valve 88 may expand the final reduction-temperature hydrogen stream 82 via Isenthal-Pick expansion. The hydrogen storage expansion valve 88 may reduce the pressure of the final reduction-temperature hydrogen stream 82 to, for example, 10 bar or less, or 0.005 to 5 bar, or 0.05 to 0.5 bar. The temperature of the final reduction-temperature hydrogen stream 82 in the hydrogen storage tank 90 may be between 34 and 14 K. The volume of the hydrogen storage tank is not particularly limited and may be, for example, 100 to 500 liters, or 150 to 350 liters.

[0026] The expansion valves 28, 38, 88 may each independently be a Joule-Thomson (JT) valve or other expansion device including a fixed orifice or line restriction. The expansion valves 28, 38, 88 may each independently utilize a fixed flow restriction and / or incorporate a heating element to reduce the risk of clogging. Additionally, an upstream purification unit may be added as needed to further reduce the risk of clogging. Alternative refrigeration cycles, including the Claude cycle, may use an isentropic expansion device such as a turbine or piston.

[0027] Each storage tank may independently be vacuum jacketed or sized to hold approximately 20 days of product from system operation. Each storage tank may independently utilize low-conductivity backing and multi-layer insulation to minimize parasitic heat leakage. Each storage tank may independently utilize an axial spray bar to distribute the supplied fluid and maintain isothermal storage conditions. Each storage tank may independently include an internal temperature rake to obtain the stratification and liquid level of each tank. Each storage tank may independently utilize common cryogenic fluid management equipment such as diffusers, fill ports, drain ports, vents, abatement devices, and vaporizers.

[0028] A portion of the hydrogen stored in the hydrogen storage tank 90 may be removed as a liquid drain 94 for hydrogen removal as needed. A portion of the stored hydrogen may be removed from the hydrogen storage tank 90 as a hydrogen recycle stream 92. The hydrogen recycle stream 92 may be introduced into the third recuperative heat exchanger 80. Heat may flow from the further reduced temperature hydrogen stream 72 (HP stream 72) to the hydrogen recycle stream 92 (LP stream 92), effectively cooling the HP stream 72. The LP stream 92 may exit the third recuperative heat exchanger 80 as a first warmed hydrogen stream 84. The first warmed hydrogen stream 84 may have a temperature of 45-80 K, or 50-75 K.

[0029] The first warmed hydrogen stream 84 and the heat-exchanged hydrogen stream 76 may be introduced into the second recuperative heat exchanger 70. Heat may flow from the radiator-cooled hydrogen stream 62 to the first warmed hydrogen stream 84, effectively cooling the radiator-cooled hydrogen stream 62. The first warmed hydrogen stream 84 may exit the second recuperative heat exchanger 70 as the second warmed hydrogen stream 78. The second warmed hydrogen stream 78 may have a temperature between 80 and 210 K, or between 90 and 180 K.

[0030] The second warmed hydrogen stream 78 may be introduced into the first recuperative heat exchanger 50. Heat may flow from the compressed hydrogen stream 42 to the second warmed hydrogen stream 78, effectively cooling the compressed hydrogen stream 42. The second warmed hydrogen stream 78 may exit the first recuperative heat exchanger 50 as a third warmed hydrogen stream 54. The third warmed hydrogen stream 54 may have a temperature of 200-350K, or 250-300K.

[0031] The third warmed hydrogen stream 54 may be combined with the separated hydrogen stream 16 and introduced into the electrochemical hydrogen compressor 40 .

[0032] 1 is based on a Joule-Thompson refrigeration cycle, those skilled in the art will understand that other refrigeration cycles may be used. For example, the present technology applies to a variety of other hydrogen refrigerant-based cycles, including Claude cycles using turboexpanders, dual pressure cycles, multi-stage cycles, and multi-pressure cycles.

[0033] FIG. 2 further illustrates the chemical processing portion of the system. While FIG. 2 illustrates water being supplied to the cathode chamber 160 of the electrolyzer 10, it should be noted that the system can be reconfigured to supply water to the anode chamber 120 of the electrolyzer 10. In FIG. 2, water stream 8 can be sent to the cathode chamber 160 of the electrolyzer 10. There, the water can contact an electrolyzer MEA including an electrolyzer proton exchange membrane 140 with catalytic electrodes, electrolyzer anode 130 and electrolyzer cathode 150, located on either side to facilitate electrochemical half-reactions. The water is transported through the electrolyzer proton exchange membrane 140 and contacts the electrolyzer anode 130, where it is separated into oxygen and hydrogen using a small voltage, allowing the water to be electrochemically split into oxygen and hydrogen. A separated oxygen stream 12 can exit the anode chamber 120 of the electrolyzer 10. The separated oxygen stream 12 can have a pressure of 10 to 40 bar.

[0034] At the electrolyzer anode 130, depending on the polarity of the applied voltage, protons that were separated from water at the anode can be sent back across the electrolyzer proton exchange membrane 140, and electrons can be bussed via an external circuit. The protons driven through the electrolyzer proton exchange membrane 140 can combine with electrons bussed from the external circuit at the electrolyzer cathode 150 of the electrolyzer MEA to form molecular hydrogen in the electrolyzer cathode chamber 160. A quantity of water, which may or may not be removed before being sent to the electrochemical hydrogen compressor 40, can be transported across the electrolyzer proton exchange membrane 140. For example, the separated hydrogen stream 16 can be sent to one or more hydrogen phase separators 194, with respective buoyancies allowing hydrogen to exit the top and bottom of the phase separators. The separated hydrogen can be sent to a regenerative heat exchanger 196 to remove waste heat from the electrolysis process before being introduced into the electrochemical hydrogen compressor 40. The separated water may be sent to a heat exchanger (not shown) at least before being reintroduced into the electrolyzer 10 .

[0035] At least one of the anode side chamber 120 or the cathode side chamber 160 can include at least one of a woven screen or a plate with open channels. At least one of the anode side chamber 120 or the cathode side chamber 160 can include expanded sheet metal that can function as a fluid flow field.

[0036] An electrolyzer power supply 170 can be used to apply a voltage to the electrolyzer MEA. The applied voltage can be 2 volts (V) or less, or 1.2-2 volts, or 1.5-2 volts. The power source can be a solar array, a direct current (DC) power source, a wind turbine (if terrestrial), a battery (e.g., a flow battery), a fuel cell, etc.

[0037] The separated oxygen stream 12 may be saturated with water vapor. The separated oxygen stream 12 may be sent to an oxygen dryer 190 to remove water from the stream before being sent to a deep space oxygen radiator 20. The oxygen dryer 190 may be a membrane-based dryer (such as a hollow fiber membrane dryer). The separated oxygen stream 12 may flow through a heat exchanger 188 before entering the oxygen dryer 190. In the oxygen dryer 190, the separated oxygen stream 12 flows on the shell side, the purge gas flows inside the membrane, and water vapor from the separated oxygen stream 12 may diffuse across the membrane for recycling back into the system forming the saturated oxygen stream 186. Here, the oxygen can be cooled by expanding the slipstream through a flow restrictor to improve the water removal efficiency of the oxygen dryer 190. After drying, the separated oxygen stream 12 may contain less than 30 parts per million by weight of water (ppm) by weight, based on the total weight of the stream.

[0038] As shown in FIG. 2 , the saturated oxygen stream 186 may be mixed with the hydrogen stream 202 from the hydrogen phase separator 194 and the hydrogen from the third warmed hydrogen stream 54 from the liquefaction process. The respective hydrogen streams may be combined in various ways upstream of one or more units, as needed. For example, to conserve water, one or more of the hydrogen streams may be sent to a catalytic reactor 192 to combine any remaining oxygen with the hydrogen to produce water. One or more of the hydrogen streams may be sent to a regenerative heat exchanger 196 to raise the gas temperature above the water saturation temperature before entering the catalytic reactor 192. The oxygen concentration in the hydrogen may be less than 2.3 wt %, based on the total weight of the stream at the inlet to the catalytic reactor 192. In the catalytic reactor 192, the hydrogen and oxygen may combine to form water vapor. Upon exiting the catalytic reactor 192, the hydrogen and water streams may be sent to a regenerative heat exchanger 196, where the heat of reaction may heat the incoming hydrogen stream. Upon exiting the regenerative heat exchanger 196, the hydrogen and water streams may be sent to a low-pressure hydrogen phase separator 198 before the separated hydrogen streams are sent to the electrochemical hydrogen compressor 40. Additionally, the hydrogen used to purify (purge) the hydrogen dryer 290 may be sent to the low-pressure hydrogen phase separator 198. The hydrogen dryer 290 may be a membrane-based dryer. Instead of expanding the product gas and treating the cold purge stream, the purge gas can be taken from the hydrogen returned from the liquefaction process as the third warmed hydrogen stream 54. The purge gas and water vapor from the hydrogen dryer 290 flow to the low-pressure hydrogen phase separator 198, allowing for 100% by weight recovery of the water and purge gas.

[0039] FIG. 2 illustrates that the separated hydrogen stream 16, the third warmed hydrogen stream 54, and the additional hydrogen stream may be routed to a low-pressure chamber 220 of the electrochemical hydrogen compressor 40 to form a hydrogen-rich gas mixture on the anode side of the electrochemical hydrogen compressor 40. The pressure in the low-pressure chamber 220 may be atmospheric, subatmospheric, or between 0.2 kilopascals (kPa) and 50 megapascals (MPa), or between 100 kilopascals and 5 MPa, or between 0.1 and 1 MPa. Note that the upper pressure limit of the low-pressure chamber 220 may be limited by the pressure threshold of the membranes. Exceeding the pressure threshold may result in mechanical failure of one of the membranes.

[0040] The hydrogen-rich gas mixture in the low-pressure chamber 220 can be exposed to the compressor MEA. The compressor MEA can use a small voltage to electrochemically compress hydrogen from the low-pressure anode side of the compressor MEA to high pressure on the cathode side of the compressor MEA. The reduction potential of the electrochemical reaction, characterized by the Nernst equation, can carry a value equivalent to that required for ideal isothermal compression. An additional small voltage can be applied to fill the ohmic resistance of the compressor PEM 240 and accelerate the catalytic effect at the electrode. Hydrogen can be evaporated from the cell's cathode along with water and transported across the compressed PEM 240 along with the protons. The transported water emerges from the cathode in liquid form, and the high-pressure hydrogen gas can become saturated with water vapor at the operating pressure and temperature of the high-pressure chamber 260.

[0041] The hydrogen-rich gas mixture in the low-pressure chamber 220 contacts the compressor MEA. The compressor MEA may include a compressor proton exchange membrane 240 with catalytic electrodes, compressor anode 230 and compressor cathode 250, positioned on either side to facilitate an electrochemical half-reaction. Hydrogen from the low-pressure chamber 220 in contact with the anode may split into protons and electrons via electrochemical reaction (1). TIFF0007820301000001.tif7160 Protons formed from reaction (1) are driven across the compressor proton exchange membrane 240 by the polarity of the applied voltage, and electrons formed from reaction (1) can be bused through an external circuit. The protons driven through the compressor proton exchange membrane 240 can be combined with electrons bused from the external circuit at the compressor cathode 250 of the compressor MEA by electrochemical reaction (2). TIFF0007820301000002.tif7160

[0042] A compressor power supply 270 may be used to apply a voltage to the compressor MEA. The applied voltage may be 1 volt (V) or less, or 0.8 volts or less, or 0.5 volts or less, or 0.01 to 0.2 volts. The power source may be a solar cell, a direct current (DC) power source, a windmill (if terrestrial), a battery (e.g., a flow battery), a fuel cell, etc.

[0043] 2 shows that hydrogen can be collected in a high-pressure chamber 260. At least one of the high-pressure chamber 260 or the low-pressure chamber 220 can include at least one of a woven screen or a plate with open channels or pores. For example, the low-pressure side of the cell can include a porous plate to provide support for the membrane under high differential pressure. At least one of the high-pressure chamber 260 or the low-pressure chamber 220 can include expanded sheet metal that can function as a fluid flow field.

[0044] The reformed hydrogen may become saturated with water vapor at the temperature and pressure of the high pressure chamber 260. The pressure of the high pressure chamber 260 may be 5-100 MPa, or 10-50 MPa, or 10-20 MPa. Note that the maximum pressure of the high pressure chamber 260 may be limited solely by the mechanical robustness of the high pressure chamber 260 and the ability of the compressor MEA to withstand the pressure differential across the compressor proton exchange membrane 240.

[0045] A certain amount of liquid condensed water may be recovered from the high pressure chamber 260 via a phase split located upstream of the hydrogen dryer 290. The condensed water may be recycled, for example, by introducing the recovered water from the hydrogen dryer 290 into the electrochemical hydrogen compressor 40, where the humidified hydrogen from the hydrogen dryer 290 may be sent to a phase separator 198 and the dry hydrogen 42 may be sent to the first recuperative heat exchanger 50.

[0046] The electrochemical hydrogen compressor 40 may further include a bleed system capable of removing dissolved gases and non-pumpable dissolved gases (e.g., nitrogen or hydrogen). For example, a bleed provision 294 may be incorporated into the anode side of the electrochemical hydrogen compressor 40. If the concentration of a gas originally dissolved in the feed water, such as nitrogen, increases, the bleed provision 294 may discharge it from the subsystem. For example, hydrogen contained in the bleed stream may be combined with oxygen introduced via an ejector and supplied to a catalytic oxidizer, and liquid water may be recovered via a pump and returned to the electrolyzer 10. Inert gases and small amounts of water vapor may be discharged from the bleed provision 294.

[0047] Each electrode (electrolyzer anode 130, electrolyzer cathode 150, compressor anode 230, or compressor cathode 250) can independently be in direct physical contact with its respective proton exchange membrane and cover 90-100% of the surface area of ​​the proton exchange membrane. Each electrode can independently include a catalyst layer. The catalyst layer can include at least one of platinum, palladium, rhodium, carbon, gold, tantalum, tungsten, ruthenium, iridium, osmium, or silver. The catalyst can include a bound catalyst. The binder can include at least one of a fluororesin or particulate carbon. The catalyst and optional binder can be deposited directly on the surface of the proton exchange membrane. The catalyst can be disposed on the gas diffusion layer, either throughout the gas diffusion layer or on the surface of the gas diffusion layer that contacts the proton exchange membrane. The gas diffusion layer can be porous. The gas diffusion layer can be a mesh. The gas diffusion layer can include a graphite-based material. The gas diffusion layer may include a plurality of fibers, such as carbon fibers. The gas diffusion layer may be electrically conductive.

[0048] Each proton exchange membrane can independently include an electrolyte such as a proton-conducting ionomer or an ion exchange resin. The proton-conducting ionomer can include a polymer complexed with at least one of an alkali metal salt, an alkaline earth metal salt, a protonic acid, or a protonic acid salt. The complexed polymer can include at least one of a polyether, a polyester, a polyimide, or a polyoxyalkylene (e.g., poly(ethylene glycol), poly(ethylene glycol monoether), or poly(ethylene glycol diether)).

[0049] The compressor proton exchange membrane 240 of the electrochemical hydrogen compressor 40 may comprise the same or different material as the electrolyzer proton exchange membrane 140 of the electrolyzer 10. For example, each proton exchange membrane may independently comprise an ionomeric polyelectrolyte comprising a certain amount of ionic groups in a hydrophobic backbone or a certain amount of pendant groups spaced from the hydrophobic backbone, such as hydrocarbon-based resins and fluororesins. The hydrocarbon-based ion exchange resin may comprise at least one of a phenolic resin or polystyrene. The hydrocarbon-based ion exchange resin may be sulfonated, for example, sulfonated poly(xylylene oxide). The hydrocarbon-based ion exchange resin may comprise at least one proton-conducting molecule, for example, a fullerene molecule, a carbon fiber, or a carbon nanotube. The proton-conducting molecule may comprise at least one proton-dissociating group, for example, —OSOH, —OPO(OH), —COOH, —OH, —SOH, —CH, or —SOH. The proton-conducting molecules can form the proton exchange membrane alone, or they can be present in a mixture with at least one binder polymer, such as a fluorine-based polymer (e.g., polyfluoroethylene (e.g., polytetrafluoroethylene), or poly(vinylidene fluoride)), or poly(vinyl alcohol)). Because the proton exchange membrane of the electrochemical hydrogen compressor 40 does not have significant amounts of oxygen, oxidation is less of a concern, and the proton exchange membrane can include a hydrocarbon-based ion exchange resin.

[0050] The fluorocarbon-type ion exchange resin may comprise at least one hydrate of tetrafluoroethylene-perfluorosulfonylethoxyvinyl ether or tetrafluoroethylene-hydroxyl group-containing (perfluorovinyl ether) copolymer. The fluorocarbon-type ion exchange resin may have at least one of sulfonic acid functional groups, carboxylic acid functional groups, or phosphoric acid functional groups. The fluorocarbon-type ion exchange resin may be a sulfonated fluororesin (e.g., lithium salt of perfluoroethylene sulfonic acid). An example of a fluorocarbon-type ion exchange resin is Nafion®, available from DuPont. TM There is.

[0051] Described below are non-limiting aspects of the present disclosure.

[0052] First Aspect. A water electrolysis and low-temperature hydrogen liquefaction system includes: a water stream in fluid communication with an anode chamber of an electrolyzer, the electrolyzer including the anode chamber, a cathode chamber, and an electrolyzer membrane and electrode assembly located between the anode chamber and the cathode chamber; a deep-space oxygen radiator in fluid communication with the anode chamber of the electrolyzer via a separated oxygen stream; a low-temperature heat exchanger including an oxygen storage tank in fluid communication with the deep-space oxygen radiator via a cooled oxygen stream; an electrochemical hydrogen compressor in fluid communication with the cathode chamber via a separated hydrogen stream; and a hydrogen storage tank in fluid communication with the electrochemical hydrogen compressor via a hydrogen stream cooled by at least one recuperative heat exchanger and at least one deep-space hydrogen radiator. At least a portion of the cooled hydrogen stream is in first fluid communication with an expansion valve and the low-temperature heat exchanger located downstream of the expansion valve, the hydrogen storage tank is in second fluid communication with the electrochemical hydrogen compressor via a heated hydrogen stream that is warmed by the at least one recuperative heat exchanger, and the low-temperature heat exchanger is in fluid communication with the heated hydrogen stream via the heat-exchanged hydrogen stream.

[0053] Aspect 2. The system of aspect 1, wherein the electrochemical hydrogen compressor includes a low-pressure chamber, a high-pressure chamber, and a compressor membrane and electrode assembly positioned between the low-pressure chamber and the high-pressure chamber, wherein the separated hydrogen stream is in fluid communication with the low-pressure chamber and the cooled hydrogen stream is in fluid communication with the high-pressure chamber.

[0054] Aspect 3. The system of aspect 1 or aspect 2, wherein the expansion valve is a Joule-Thomson valve.

[0055] Aspect 4. The system of any of aspects 1 to 3, further comprising an oxygen expansion valve located along the cooled oxygen flow upstream of the oxygen storage tank, the oxygen expansion valve optionally being a Joule-Thomson valve.

[0056] Aspect 5. The system of any of aspects 1 to 4, further comprising a hydrogen storage expansion valve located along the cooled hydrogen flow upstream of the hydrogen storage tank, the hydrogen storage expansion valve optionally being a Joule-Thomson valve.

[0057] A sixth aspect: In the system of any one of the first to fifth aspects, the at least one recuperative heat exchanger includes a first recuperative heat exchanger, a second recuperative heat exchanger, and a third recuperative heat exchanger, the first recuperative heat exchanger being in first fluid communication with the electrochemical hydrogen compressor via a compressed hydrogen stream, the deep space hydrogen radiator being in first fluid communication with the first recuperative heat exchanger via a first reduced temperature hydrogen stream, and the second recuperative heat exchanger being in first fluid communication with the electrochemical hydrogen compressor via a radiator-cooled hydrogen stream. , in the first fluid communication with the deep space hydrogen radiator, the third recuperative heat exchanger in the first fluid communication with the second recuperative heat exchanger via a further reduced-temperature hydrogen stream, the hydrogen storage tank in the first fluid communication with the third recuperative heat exchanger via a final reduced-temperature hydrogen stream, and the cooled hydrogen streams include the compressed hydrogen stream, the first reduced-temperature hydrogen stream, the radiator-cooled hydrogen stream, the further reduced-temperature hydrogen stream, and the final reduced-temperature hydrogen stream.

[0058] Aspect 7. The system of aspect 6, wherein the warmed hydrogen streams include a hydrogen recycle stream, a first warmed hydrogen stream, a second warmed hydrogen stream, and a third warmed hydrogen stream, the hydrogen storage tank is in the second fluid communication with the third recuperative heat exchanger via the hydrogen recycle stream, the third recuperative heat exchanger is in the second fluid communication with the second recuperative heat exchanger via the first warmed hydrogen stream, the second recuperative heat exchanger is in the second fluid communication with the first recuperative heat exchanger via the second warmed hydrogen stream, and the first recuperative heat exchanger is in the second fluid communication with the electrochemical hydrogen compressor via the third warmed hydrogen stream.

[0059] Aspect 8. The system of any one of aspects 1 to 7, further comprising a dryer located along the separated oxygen flow upstream of the deep space oxygen radiator.

[0060] Aspect 9. The system of any one of aspects 1 to 8, further comprising a catalytic reactor in fluid communication with the at least one recuperative heat exchanger or the electrolyzer, and also in fluid communication with the electrochemical hydrogen compressor.

[0061] Aspect 10: In the system of any one of aspects 1 to 9, the low-temperature heat exchanger is a shell-in-tube heat exchanger.

[0062] Eleventh aspect: A method for electrolyzing water and producing liquid oxygen therefrom at low temperatures using, for example, any one or more of the systems of the first to tenth aspects, the method including: sending a water flow to at least one of an anode chamber or a cathode chamber of an electrolytic cell, wherein the electrolytic cell includes the anode chamber, the cathode chamber, and an electrolytic membrane and electrode assembly located between the anode chamber and the cathode chamber; sending a separated oxygen flow from the anode chamber of the electrolytic cell to a deep-space oxygen radiator; sending the cooled oxygen flow from the deep-space oxygen radiator to an oxygen storage tank of a low-temperature heat exchanger; sending a hydrogen stream; sending a cooled hydrogen stream from the electrochemical hydrogen compressor to a hydrogen storage tank, cooling the cooled hydrogen stream with at least one recuperative heat exchanger and at least one deep space hydrogen radiator upstream of the hydrogen storage tank; expanding at least a portion of the cooled hydrogen stream in an expansion valve to form a refrigerant hydrogen stream; sending the refrigerant hydrogen stream to the low-temperature heat exchanger; sending a warmed hydrogen stream from the hydrogen storage tank to the electrochemical hydrogen compressor, warming the warmed hydrogen stream via the at least one recuperative heat exchanger; and sending a heat-exchanged hydrogen stream from the low-temperature heat exchanger to the warmed hydrogen stream upstream of the electrochemical hydrogen compressor.

[0063] Aspect 12. The method of aspect 11, wherein the electrochemical hydrogen compressor includes a low-pressure chamber, a high-pressure chamber, and a compressor membrane and electrode assembly located between the low-pressure chamber and the high-pressure chamber, the method comprising passing the separated hydrogen stream into the low-pressure chamber and passing the cooled hydrogen stream from the high-pressure chamber.

[0064] Aspect 13. The method of aspect 11 or aspect 12, wherein the expansion valve is a Joule-Thomson valve.

[0065] Aspect 14. The method of any of aspects 11 to 13, further comprising expanding the cooled oxygen stream upstream of the oxygen storage tank through an oxygen expansion valve, which is optionally a Joule-Thomson valve.

[0066] Aspect 15. The method of any of aspects 11 to 14, further comprising expanding the cooled hydrogen stream upstream of the hydrogen storage tank through a hydrogen storage expansion valve, which is optionally a Joule-Thomson valve.

[0067] Aspect 16. The method of any of aspects 11 to 15, wherein the at least one recuperative heat exchanger includes a first recuperative heat exchanger, a second recuperative heat exchanger, and a third recuperative heat exchanger, and the method includes cooling the compressed hydrogen stream of the first recuperative heat exchanger to form a first reduced-temperature hydrogen stream, cooling the first reduced-temperature hydrogen stream of the deep-space hydrogen radiator to form a radiator-cooled hydrogen stream, cooling the radiator-cooled hydrogen stream of the second recuperative heat exchanger to form a further reduced-temperature hydrogen stream, and cooling the further reduced-temperature hydrogen stream of the third recuperative heat exchanger to form a final reduced-temperature hydrogen stream. The cooled hydrogen streams include the compressed hydrogen stream, the first reduced-temperature hydrogen stream, the radiator-cooled hydrogen stream, the further reduced-temperature hydrogen stream, and the final reduced-temperature hydrogen stream.

[0068] Aspect 17. The method of aspect 16, wherein the warmed hydrogen streams include a hydrogen recycle stream, a first warmed hydrogen stream, a second warmed hydrogen stream, and a third warmed hydrogen stream, the method comprising removing the hydrogen recycle stream from the hydrogen storage tank, warming the hydrogen recycle stream in the third recuperative heat exchanger to form the first warmed hydrogen stream, warming the first warmed hydrogen stream in the second recuperative heat exchanger to form the second warmed hydrogen stream, warming the second warmed hydrogen stream in the first recuperative heat exchanger to form the third warmed hydrogen stream, and sending the third warmed hydrogen stream to the electrochemical hydrogen compressor.

[0069] Aspect 18. The method of any one of aspects 11 to 17, further comprising drying the separated oxygen stream in a dryer before sending the separated oxygen stream to the deep space oxygen radiator.

[0070] Aspect 19. The method of any of aspects 11 to 18, further comprising passing the warmed hydrogen stream or the separated water vapor stream from the separated oxygen stream to a catalytic reactor to form a reduced oxygen stream, and passing the reduced oxygen stream to the electrochemical hydrogen compressor.

[0071] Aspect 20: In the method according to any one of aspects 11 to 19, the low-temperature heat exchanger is a shell-in-tube heat exchanger.

[0072] The compositions, methods and articles may alternatively comprise, consist of, or consist essentially of any suitable material, step, or ingredient disclosed herein. The compositions, methods and articles may additionally or alternatively be configured to be free of, or substantially free of, any material (or species), step, or ingredient that is not necessary to achieve the function or purpose of the compositions, methods and articles.

[0073] As used herein, "a," "an," "the," and "at least one" do not denote limitations of quantity and are intended to cover both the singular and the plural, unless the context clearly dictates otherwise. For example, "an element" has the same meaning as "at least one element," unless the context clearly dictates otherwise. The term "at least one" means that a list includes not only each element individually, but also combinations of two or more elements of the list, and combinations of at least one element of the list with a similar element not named. The term "combination" is also inclusive of blends, mixtures, alloys, reaction products, and the like.

[0074] The term "or" means "and / or" unless the context clearly dictates otherwise. References throughout this specification to "one aspect," "one embodiment," "another embodiment," "some embodiments," etc. mean that a particular element (e.g., a feature, structure, step, or characteristic) described in connection with an embodiment is included in at least one embodiment described herein and may or may not be present in other embodiments. In addition, it will be understood that the described elements may be combined in any suitable manner in the various embodiments.

[0075] The endpoints of all ranges directed to the same ingredient or property are inclusive, independently combinable, and include all intermediate points and ranges. For example, a range "up to 25 wt% or 5-20 wt%" includes the endpoints and all intermediate values ​​in the "5-25 wt%" range, such as 10-23 wt%.

[0076] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0077] All cited patents, patent applications, and other references are incorporated herein by reference in their entirety, except that if a term in this application contradicts or conflicts with a term in the incorporated document, the term in this application will control over the conflicting term in the incorporated document.

[0078] While particular embodiments have been described, presently unforeseen or foreseeable alternatives, modifications, variations, improvements, and substantial equivalents may occur to applicant or those skilled in the art. Accordingly, the appended claims, as filed and as they may be amended, are intended to embrace all such alternatives, modifications, variations, improvements, and substantial equivalents.

Claims

1. a water stream in fluid communication with an anode chamber of an electrolytic cell, the electrolytic cell including the anode chamber, a cathode chamber, and an electrolytic cell membrane and electrode assembly located between the anode chamber and the cathode chamber; a deep-space oxygen radiator in fluid communication with the anode chamber of the electrolyzer via a separated oxygen stream, the deep-space oxygen radiator pre-cooling the separated oxygen stream; a cryogenic heat exchanger including an oxygen storage tank in fluid communication with the deep space oxygen radiator via a cooled oxygen stream; an electrochemical hydrogen compressor in fluid communication with the cathode chamber via a separated hydrogen stream; at least one recuperative heat exchanger and at least one deep space hydrogen radiator for pre-cooling the hydrogen stream compressed by the electrochemical hydrogen compressor; a hydrogen storage tank in fluid communication with the electrochemical hydrogen compressor via a hydrogen flow cooled by the at least one recuperative heat exchanger and the at least one deep space hydrogen radiator; at least a portion of the cooled hydrogen stream is in first fluid communication with an expansion valve and the low-temperature heat exchanger downstream of the expansion valve; the cryogenic heat exchanger uses at least a portion of the cooled hydrogen stream as a refrigerant to cryogenically liquefy the cooled oxygen stream in the oxygen storage tank; the hydrogen storage tank is in second fluid communication with the electrochemical hydrogen compressor via a heated hydrogen stream heated by the at least one recuperative heat exchanger; The water electrolysis and low-temperature liquefaction system, wherein the low-temperature heat exchanger is in fluid communication with the warmed hydrogen stream via a heat-exchanged hydrogen stream.

2. 2. The system of claim 1, wherein the electrochemical hydrogen compressor includes a low-pressure chamber, a high-pressure chamber, and a compressor membrane and electrode assembly positioned between the low-pressure chamber and the high-pressure chamber, the separated hydrogen stream being in fluid communication with the low-pressure chamber and the cooled hydrogen stream being in fluid communication with the high-pressure chamber.

3. The system of claim 1 or 2, wherein the expansion valve is a Joule-Thomson valve.

4. 4. The system of claim 1, further comprising an oxygen expansion valve located along the cooled oxygen flow upstream of the oxygen storage tank, the oxygen expansion valve being a Joule-Thomson valve.

5. 5. The system of claim 1, further comprising a hydrogen storage expansion valve located along the cooled hydrogen flow upstream of the hydrogen storage tank, the hydrogen storage expansion valve being a Joule-Thomson valve.

6. the at least one recuperative heat exchanger includes a first recuperative heat exchanger, a second recuperative heat exchanger, and a third recuperative heat exchanger; the first recuperative heat exchanger is in first fluid communication with the electrochemical hydrogen compressor via a compressed hydrogen stream; the deep space hydrogen radiator is in first fluid communication with the first recuperative heat exchanger via a first reduced-temperature hydrogen stream; the second recuperative heat exchanger is in first fluid communication with the deep space hydrogen radiator via a radiator-cooled hydrogen flow; the third recuperative heat exchanger is in the first fluid communication with the second recuperative heat exchanger via a further reduced-temperature hydrogen stream; the hydrogen storage tank is in first fluid communication with the third recuperative heat exchanger via a final reduced temperature hydrogen stream; 6. The system of claim 1, wherein the cooled hydrogen streams include the compressed hydrogen stream, the first reduced-temperature hydrogen stream, the radiator-cooled hydrogen stream, the further reduced-temperature hydrogen stream, and the final reduced-temperature hydrogen stream.

7. the warmed hydrogen streams include a hydrogen recycle stream, a first warmed hydrogen stream, a second warmed hydrogen stream, and a third warmed hydrogen stream; the hydrogen storage tank is in second fluid communication with the third recuperative heat exchanger via the hydrogen recycle stream; the third recuperative heat exchanger is in second fluid communication with the second recuperative heat exchanger via the first warmed hydrogen stream; the second recuperative heat exchanger is in second fluid communication with the first recuperative heat exchanger via the second warmed hydrogen stream; 7. The system of claim 6, wherein the first recuperative heat exchanger is in second fluid communication with the electrochemical hydrogen compressor via the third warmed hydrogen stream.

8. The system of any preceding claim, further comprising a dryer located along the separated oxygen flow upstream of the deep space oxygen radiator.

9. 9. The system of claim 1, further comprising a catalytic reactor in fluid communication with the at least one recuperative heat exchanger or the electrolyzer, and also in fluid communication with the electrochemical hydrogen compressor.

10. The system according to any one of claims 1 to 9, wherein the low-temperature heat exchanger is a shell-in-tube heat exchanger.

11. A method for electrolyzing water and producing liquid oxygen therefrom at low temperatures, comprising: sending a water flow to at least one of an anode chamber or a cathode chamber of an electrolytic cell, the electrolytic cell including the anode chamber, the cathode chamber, and an electrolytic membrane and electrode assembly located between the anode chamber and the cathode chamber; directing a separated oxygen stream from the anode chamber of the electrolyzer to a deep space oxygen radiator; the deep space oxygen radiator pre-cooling the separated oxygen stream; delivering a cooled oxygen stream from the deep space oxygen radiator to an oxygen storage tank of a cryogenic heat exchanger; directing the separated hydrogen stream from the cathode chamber to an electrochemical hydrogen compressor; sending a cooled hydrogen stream from the electrochemical hydrogen compressor to a hydrogen storage tank, and pre-cooling the cooled hydrogen stream with at least one recuperative heat exchanger and at least one deep space hydrogen radiator upstream of the hydrogen storage tank; expanding at least a portion of said cooled hydrogen stream in an expansion valve to form a refrigerant hydrogen stream, and passing said refrigerant hydrogen stream to said cryogenic heat exchanger; the cryogenic heat exchanger liquefies the cooled oxygen stream in the oxygen storage tank using the refrigerant hydrogen stream; delivering a heated hydrogen stream from the hydrogen storage tank to the electrochemical hydrogen compressor and warming the heated hydrogen stream through the at least one recuperative heat exchanger; and sending a heat-exchanged hydrogen stream from the cryogenic heat exchanger to the warmed hydrogen stream upstream of the electrochemical hydrogen compressor.

12. 12. The method of claim 11, wherein the electrochemical hydrogen compressor includes a low-pressure chamber, a high-pressure chamber, and a compressor membrane and electrode assembly located between the low-pressure chamber and the high-pressure chamber, the method comprising passing the separated hydrogen stream into the low-pressure chamber and passing the cooled hydrogen stream from the high-pressure chamber.

13. 13. The method of claim 11 or 12, wherein the expansion valve is a Joule-Thomson valve.

14. 14. The method of any of claims 11 to 13, comprising expanding the cooled oxygen stream upstream of the oxygen storage tank through an oxygen expansion valve, the oxygen expansion valve being a Joule-Thomson valve.

15. 15. The method of any of claims 11 to 14, comprising expanding the cooled hydrogen stream upstream of the hydrogen storage tank through a hydrogen storage expansion valve, the hydrogen storage expansion valve being a Joule-Thomson valve.

16. the at least one recuperative heat exchanger includes a first recuperative heat exchanger, a second recuperative heat exchanger, and a third recuperative heat exchanger; The method comprises: cooling the compressed hydrogen stream in the first recuperative heat exchanger to form a first reducing temperature hydrogen stream; cooling the first reduced-temperature hydrogen stream of the deep space hydrogen radiator to form a radiator-cooled hydrogen stream; cooling the radiator-cooled hydrogen stream in the second recuperative heat exchanger to form a further reducing-temperature hydrogen stream; and cooling the further reducing-temperature hydrogen stream in the third recuperative heat exchanger to form a final reducing-temperature hydrogen stream; 16. The method of any of claims 11 to 15, wherein the cooled hydrogen streams comprise the compressed hydrogen stream, the first reduced-temperature hydrogen stream, the radiator-cooled hydrogen stream, the further reduced-temperature hydrogen stream, and the final reduced-temperature hydrogen stream.

17. the warmed hydrogen streams include a hydrogen recycle stream, a first warmed hydrogen stream, a second warmed hydrogen stream, and a third warmed hydrogen stream; The method comprises: removing the hydrogen recycle stream from the hydrogen storage tank; warming the hydrogen recycle stream in the third recuperative heat exchanger to form the first warmed hydrogen stream; warming the first warmed hydrogen stream in the second recuperative heat exchanger to form the second warmed hydrogen stream; warming the second warmed hydrogen stream in the first recuperative heat exchanger to form the third warmed hydrogen stream; and sending said third warmed hydrogen stream to said electrochemical hydrogen compressor; 17. The method of claim 16, comprising:

18. The method of any of claims 11 to 17, comprising drying the separated oxygen stream in a dryer before sending the separated oxygen stream to the deep space oxygen radiator.

19. 19. The method of any of claims 11 to 18, comprising passing the warmed hydrogen stream or the separated water vapor stream from the separated oxygen stream to a catalytic reactor to form a reduced oxygen stream, and passing the reduced oxygen stream to the electrochemical hydrogen compressor.

20. The method according to any one of claims 11 to 19, wherein the low-temperature heat exchanger is a shell-in-tube heat exchanger.

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