Method and system for hydrogen purification

Abstract

A method comprising partially condensing and separating a feed stream comprising helium and hydrogen to produce a first intermediate pressure vapor stream and a first intermediate pressure liquid stream; flashing the first intermediate pressure liquid stream or a stream derived from the first intermediate pressure liquid stream to produce a low pressure vapor stream and a low pressure liquid stream; cooling the first intermediate pressure vapor stream by indirect heat exchange with the low pressure liquid stream to produce a first partially condensed intermediate pressure stream; and separating the first partially condensed intermediate pressure stream to produce a second intermediate pressure vapor stream and a second intermediate pressure liquid stream.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application 63 / 570,268, filed March 27, 2024, which is incorporated herein by reference. Background Technology

[0003] If decarbonized hydrogen sources can be found, hydrogen could become a means of reducing carbon intensity in sectors such as transportation, power generation, and chemicals. One potential low-carbon hydrogen source is natural hydrogen, primarily produced through geochemical processes such as serpentinization (the reaction of water with ferrous minerals). Hydrogen formed in this way can rise through geological layers until it is trapped by impermeable rocks, thus forming reservoirs. Rare gases such as helium and argon can similarly form underground through radioactive decay and be trapped. Natural hydrogen sources may require new purification processes because in industrial hydrogen sources (such as those from steam methane reforming), impurities that must be removed may have varying concentrations or be completely absent. Attached Figure Description

[0004] The invention will now be described in conjunction with the accompanying drawings, wherein the same numerals denote the same elements:

[0005] Figure 1 This is a schematic diagram depicting one embodiment of a hydrogen purification process according to one or more aspects of this disclosure.

[0006] Figure 2 This is a schematic diagram depicting another embodiment of a hydrogen purification process according to one or more aspects of this disclosure.

[0007] Figure 3 It is a description Figure 2 A schematic diagram of a variant in which the hydrogen feed does not require purification in the membrane before adsorption purification.

[0008] Figure 4A This is a schematic diagram depicting an alternative to hydrogen-helium separation, in which a hydrogen-helium stream is burned to generate electricity.

[0009] Figure 4B This is a schematic diagram depicting an alternative to hydrogen-helium separation, in which a hydrogen-helium stream is catalytically oxidized to convert hydrogen into water.

[0010] Figure 5 This is a schematic diagram of a helium recovery process, in which hydrogen is first fed in and burned to generate electricity, and helium is recovered from the combustion products.

[0011] Figure 6 This is a schematic diagram of an exhaust gas separation process in which methane, nitrogen, and / or argon are recovered from the exhaust gas stream, thereby allowing the remaining hydrogen-helium mixture to be recycled.

[0012] Figure 7 This is a schematic diagram of a low-temperature hydrogen purifier according to one or more aspects of this disclosure.

[0013] Figure 8 yes Figure 7 A schematic diagram of a variant that produces liquid hydrogen products.

[0014] Figure 9 yes Figure 8 A schematic diagram of a variant, in which the intermediate flash evaporator is omitted.

[0015] Figure 10 yes Figure 9 A schematic diagram of a variant in which the first medium-pressure flash evaporator is replaced by a medium-pressure distillation column.

[0016] Figure 11 yes Figure 8 A schematic diagram of a variant, in which the first intermediate-pressure flash evaporator is omitted.

[0017] Figure 12 This is a schematic diagram of a process for producing ammonia from a hydrogen feed stream containing helium impurities.

[0018] Figure 13 It is a description Figure 12 A schematic diagram of a variant in which hydrogen PSA is used to purify the hydrogen feed stream.

[0019] Figure 14 It is a description Figure 12 A schematic diagram of a variant in which a hydrogen feed stream reacts with a precursor to form a hydrogen carrier. Detailed Implementation

[0020] The following detailed description provides only preferred exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the detailed description of preferred exemplary embodiments below will provide those skilled in the art with a description of the implementability of the preferred exemplary embodiments of the invention. Various changes may be made to the function and arrangement of the elements without departing from the spirit and scope of the invention as set forth in the appended claims.

[0021] This disclosure relates to methods and systems for purifying hydrogen feed streams. The methods and systems may also include the recovery of byproducts (such as helium or argon) from the hydrogen feed stream.

[0022] As used herein, the article “a” or “an” when applied to any feature in the embodiments of the invention described in this specification and claims means one or more. The use of “a” and “an” does not limit the meaning to a single feature unless such limitation is explicitly stated. The article “the” preceding a singular or plural noun or noun phrase indicates a specific designated feature or a specific plurality of designated features and may have a singular or plural meaning depending on the context in which it is used.

[0023] The term “and / or” placed between the first entity and the second entity includes any of the following meanings: (1) only the first entity, (2) only the second entity, or (3) both the first entity and the second entity. The term “and / or” placed between the last two entities in a list of three or more entities means at least one entity in the list, including any particular combination of entities in the list. For example, “A, B and / or C” has the same meaning as “A and / or B and / or C” and includes the following combinations of A, B and C: (1) only A, (2) only B, (3) only C, (4) A and B but not C, (5) A and C but not B, (6) B and C but not A, and (7) A and B and C.

[0024] The adjective "any" means one, some, or all, without distinguishing the quantity.

[0025] The phrase "at least a part" means "a part or all". "At least a part of the flow" has the same composition as the flow from which it originates, and each substance in the flow has the same concentration.

[0026] As used herein, “first,” “second,” “third,” etc., are used to distinguish multiple steps and / or features and do not indicate the total number or relative position in time and / or space unless explicitly stated otherwise.

[0027] The term "lean" or "lean-containing" means that the molar percentage concentration of the indicated component is lower than that of the original stream from which it originates. "Lean" or "lean-containing" does not mean that the stream is completely free of the indicated component.

[0028] The term “rich” or “enriched” means that the molar percentage concentration of the indicated component is higher than that of the original stream from which it originated.

[0029] "Downstream" and "upstream" refer to the intended flow direction of the transferred process fluid. If the intended flow direction of the process fluid is from the first unit to the second unit, then the second unit is downstream of the first unit. In the case of recirculating flow, downstream and upstream refer to the first passage of the process fluid.

[0030] The term "indirect heat exchange" refers to the process of transferring sensible and / or latent heat between two or more fluids involved without bringing these fluids into physical contact with each other. Heat can be transferred through the walls of a heat exchanger or using an intermediate heat exchange fluid. The term "hot flow" refers to any flow that leaves a heat exchanger at a lower temperature than it entered. Conversely, "cold flow" is a flow that leaves a heat exchanger at a higher temperature than it entered.

[0031] The term "distillation column" includes fractionation columns, rectification columns, and stripping columns. "Distillation column" can refer to a single column or multiple columns connected in series or parallel, wherein the multiple columns can be any combination of the above column types. Each column may include one or more tray sections and / or packing sections.

[0032] According to this embodiment, the hydrogen feed stream may contain impurities such as helium, argon, carbon dioxide, nitrogen, water vapor, methane, and heavier hydrocarbons. Heavier hydrocarbons may include ethane, propane, butane, pentane, and hexane. The hydrogen feed stream may contain 7% to 99%, 20% to 99%, or 50% to 99% hydrogen by volume. The hydrogen feed stream may contain 0.1% to 20%, 1% to 17%, or 1% to 5% helium by volume. The hydrogen feed stream may originate from an underground reservoir.

[0033] The hydrogen feed stream can be purified in one or more membrane stages to produce at least one permeate stream enriched with fast gases (such as hydrogen and helium) and at least one residual stream enriched with slow gases (such as argon, nitrogen, and methane). Prior to purification in these one or more membrane stages, the hydrogen feed stream can be treated to remove heavy hydrocarbons, aromatic compounds, and / or water vapor, thereby protecting the membrane material. The hydrogen feed stream can be heated before entering the one or more membrane stages to prevent water condensation on the membrane.

[0034] At least one permeate stream can be further purified in a pressure swing adsorption (PSA) unit. If the hydrogen concentration in the hydrogen feed stream is high enough, the hydrogen feed stream can be directly fed into the PSA. The PSA produces a PSA product stream enriched with hydrogen and helium and a PSA tail stream enriched with impurities such as methane, argon, carbon dioxide, water vapor, and nitrogen. The PSA tail stream can be compressed and recycled to the one or more membrane stages. During compression, water vapor can be condensed and removed from the PSA tail stream.

[0035] The PSA product stream can be cooled and further purified in one or more cryogenic temperature-switching adsorption (CTSA) units to further remove impurities such as methane, argon, carbon dioxide, water vapor, and nitrogen. Multiple CTSA units can be arranged to operate at progressively lower temperatures. The PSA product stream can be cooled to temperatures ranging from 20 K to 120 K or 50 K to 80 K before being fed into the CTSA. Impurities are adsorbed onto the online bed, and the hydrogen-helium mixture exits the online bed. The online bed can utilize one or more high-surface-area adsorbents, including but not limited to zeolites, metal-organic frameworks (MOFs), alumina, silica gel, silica zeolites, activated carbon, Engelhard titanosilicon (ETS), and metal oxides. During the impurity removal steps from the PSA product stream, the adsorbent in the online bed becomes loaded with impurities, to the point where impurity removal efficiency decreases and the impurity level in the hydrogen-helium mixture may exceed specifications. At this point, the bed can be switched to regeneration mode, where regeneration gas is passed through the bed to remove impurities, and an impurity-enriched waste regeneration gas is generated. The regeneration gas may contain a portion of a hydrogen-helium mixture or pure hydrogen products. The bed can be regenerated at ambient temperature and pressure. Waste regeneration gas can be compressed and recycled to one or more membrane stages. Waste regeneration gas can be combined with PSA tail gas for compression in the same compressor.

[0036] Hydrogen-helium mixtures can be separated in cryogenic processes using any combination of flash separators and distillation columns. Cryogenic processes can be refrigerated using liquid nitrogen, liquid hydrogen, and / or by reducing the pressure of one or more streams in the process. Pressure reduction can be achieved in devices such as valves or expanders. The separation can be designed to produce a pure hydrogen product stream and a hydrogen-helium column overhead stream. The hydrogen-helium column overhead stream can have a helium to hydrogen molar ratio of approximately 3:1.

[0037] The hydrogen-helium overhead stream can be separated using several methods. Voltage can be applied to an electrochemical hydrogen pump or compressor to separate hydrogen from the overhead stream, producing a helium product stream and a second hydrogen product stream, which can be combined with the pure hydrogen product stream. The second hydrogen product stream can be generated at a higher pressure than the helium product stream. The helium product stream and / or the second hydrogen product stream may require dehydration. Alternatively, the hydrogen-helium overhead stream can be combusted to generate electricity and / or heat. Helium can be recovered from the combustion products, for example, using membrane and / or adsorption processes. Residual portions of the combustion product stream can be discharged or recycled, for example, by combining it with a PSA tail gas stream before compression. The hydrogen-helium overhead stream can be combusted with oxygen-enriched or pure oxygen to reduce the amount of nitrogen that must be removed from the combustion product stream. If the demand for electricity is insufficient, the hydrogen-helium overhead stream can be reacted with air in the presence of a catalyst to convert hydrogen into water, and the same downstream separation process can be used to recover helium.

[0038] The PSA product stream can be separated in a cryogenic process that produces a crude helium stream and liquid hydrogen products. The PSA product stream can be cooled and then purified by an adsorption process such as CTSA. When CTSA is regenerated, the waste regenerated gas stream can be recycled to an upstream purification step (such as a membrane or PSA). The waste regenerated gas stream can be recycled to a point in the process with a similar composition. The PSA product stream can be cooled and passed through an OP catalyst that catalyzes the conversion of orthohydrogen to secondary hydrogen. Maintaining a orthohydrogen to secondary hydrogen ratio close to the equilibrium value of liquid hydrogen reduces the exothermic reaction from orthohydrogen to secondary hydrogen that would otherwise increase the evaporation rate during the storage or transport of liquid hydrogen. The PSA product stream can be cooled and depressurized to produce a partially condensed hydrogen-helium mixture. Any combination of cooling, purification, OP catalytic reaction, and depressurization can be used to produce a partially condensed hydrogen-helium mixture. The partially condensed hydrogen-helium mixture can be separated to form a first medium-pressure vapor stream and a first medium-pressure liquid stream.

[0039] Partially condensed hydrogen-helium mixtures can be separated in any combination of flash vessels or distillation columns. A first intermediate-pressure liquid stream, or a stream originating from it, can be depressurized to form a partially condensed low-pressure stream, which can be separated to produce a low-pressure vapor stream and a low-pressure liquid stream. The partially condensed low-pressure stream can be separated in any combination of flash vessels or distillation columns. The low-pressure liquid stream may contain more than 97% hydrogen, or more than 98% hydrogen, or more than 99% hydrogen, or more than 99.97% hydrogen, or more than 99.9995% hydrogen. The low-pressure vapor stream can be used as a refrigerant, compressed and cooled to produce a circulating stream. The circulating stream can be combined with the partially condensed hydrogen-helium mixture. The low-pressure vapor stream can be circulated by combining with the partially condensed hydrogen-helium mixture. At least a portion of the circulating stream can be expanded to provide refrigeration to cool the PSA product stream. The first intermediate-pressure vapor stream can be cooled by heat exchange with the low-pressure liquid stream to form a first partially condensed intermediate-pressure stream. The first medium-pressure vapor stream can be cooled by indirect heat exchange with a low-pressure liquid stream, which can be integrated with a separation device for partial condensation of the low-pressure stream, a separate heat exchanger, or a heat exchanger integrated with other heat exchange loads in the cryogenic process. The medium-pressure stream from the first partial condensation can be separated to produce a crude helium vapor stream and a second medium-pressure liquid stream. The crude helium vapor stream can contain more than 10% helium, more than 50% helium, or more than 65% helium. The crude helium vapor stream can be further purified to produce pure helium products. The crude helium vapor stream can be further purified by combining with an oxidant and reacting it on a deoxygenating catalyst to react the oxidant with hydrogen; then the reaction products (such as water) can be removed by any suitable method (such as adsorption). The oxidant can contain oxygen, air, or oxygen-enriched air. The second medium-pressure liquid stream can be combined with the first medium-pressure liquid stream upstream or downstream of the first medium-pressure liquid stream at a pressure reduction. When the second medium-pressure liquid stream is combined with the first medium-pressure liquid stream downstream of the first medium-pressure liquid stream at a pressure reduction, the second medium-pressure liquid stream can be depressurized first. The second medium-pressure liquid stream can come into contact with the first medium-pressure vapor stream. In the case where the partially condensed hydrogen-helium column overhead stream is separated by a distillation column, the cooling of the first medium-pressure vapor stream can act as a condenser for the distillation column, and the second medium-pressure liquid stream can be used to wash hydrogen from the first medium-pressure vapor stream.

[0040] Before depressurization to form a partially condensed low-pressure flow, the first intermediate-pressure liquid flow can be reduced to one or more intermediate pressures connected in series or parallel. At each intermediate pressure stage, the intermediate-pressure flow can be partially condensed and separated to form an intermediate-pressure vapor flow and an intermediate-pressure liquid flow. The intermediate-pressure vapor flow can be heated, compressed, cooled, and circulated. The intermediate-pressure vapor flow can be heated by indirect heat exchange with a flow such as the overhead flow of a helium-hydrogen tower to provide cooling. The intermediate-pressure vapor flow can be circulated by merging with a partially condensed overhead flow of a hydrogen-helium tower. The intermediate-pressure liquid flow can be depressurized to produce a partially condensed low-pressure flow.

[0041] Waste streams (such as leachate streams, PSA tail gas, and / or waste regeneration gas streams) may contain significant amounts of valuable impurities (such as argon) or methane restricted by emission regulations. In these cases, water vapor and carbon dioxide can be removed from the waste stream in the TSA, the waste stream can be cooled to cryogenic temperatures, and, as needed, distilled sequentially in a series of columns to produce a second hydrogen-helium overhead stream, a nitrogen-enriched overhead stream, an argon-enriched overhead stream, and / or a methane-enriched bottom stream. For example, if nitrogen in the waste stream is negligible, a nitrogen-enriched overhead stream may not be necessary. The overhead streams can be indirectly heated to provide cooling through indirect heat exchange with the waste stream. The bottom streams exiting each column can be expanded to provide refrigeration. Additional refrigeration (such as liquid nitrogen or a closed-loop refrigeration cycle) can be used to cool the waste stream. The same heat exchanger system can also be used to cool the hydrogen-helium mixture prior to separation in the CTSA. The nitrogen-enriched overhead stream can be used to regenerate the TSA. Depending on purity, the second hydrogen-helium overhead stream can be combined with a hydrogen-helium mixture or the hydrogen-helium overhead stream. If the second hydrogen-helium tower overhead flow is recovered in this manner, the size of one or more membrane stages can be set to increase hydrogen leakage into one or more permeate streams, which can reduce the membrane size and / or increase the hydrogen concentration in one or more permeate streams.

[0042] Hydrogen feed streams can be used to produce ammonia. When the hydrogen feed stream contains helium impurities, these impurities can accumulate in the ammonia process, making an integrated hydrogen-helium separation step practical. In contrast, a typical ammonia process begins with a natural gas stream. If the natural gas stream contains commercially valuable helium, it can be separated upstream of the ammonia synthesis reactor because separating helium from methane and other hydrocarbons is simpler and less costly than separating it from hydrogen. However, in this disclosure, separating helium and hydrogen downstream of the ammonia synthesis reactor may be advantageous.

[0043] The hydrogen feed stream may contain hydrogen, helium, and other impurities such as water, carbon dioxide, oxygen, argon, methane, sulfur compounds, and heavier hydrocarbons. Other impurities can be removed upstream of the ammonia synthesis reactor, for example, using adsorption and / or absorption processes to produce a purified feed stream. Carbon dioxide and water can be removed via TSA. Impurities (such as methane) from the hydrogen feed stream can be washed with liquid nitrogen. The purified feed stream can be combined with nitrogen and, if necessary, compressed to produce the ammonia synthesis feed stream.

[0044] The ammonia synthesis reactor can operate at pressures ranging from 60 to 200 bar. In the reactor, hydrogen and nitrogen react in the presence of a catalyst to produce ammonia. The reaction product stream can then be cooled to condense at least a portion of the ammonia, forming a first ammonia product stream and an ammonia condenser overhead stream enriched with nitrogen, hydrogen, and helium. The ammonia condenser overhead stream can be indirectly heated by heat exchange with the reaction product stream. At least a portion of the ammonia condenser overhead stream can be recycled to the feed of the ammonia synthesis reactor and can be compressed as needed. At least a portion of the ammonia condenser overhead stream can be sent to an ammonia scrubbing column, which separates the stream to produce a first light component stream and a second ammonia product stream. The scrubbing column can recover ammonia from the overhead stream using a high-pressure water stream, from which the second ammonia product stream can then be vaporized. The first light component stream may contain unreacted hydrogen and nitrogen, as well as light inert components such as helium and argon. The first light component stream can be separated to form a nitrogen-rich light component stream and a nitrogen-lean light component stream. The first light component stream can be separated using any combination of membrane, adsorption, cryogenic distillation, or partial condensation. At least a portion of the nitrogen-rich light component stream can be discharged to prevent the accumulation of inert components such as argon. If the amount of argon in the discharge stream is commercially viable, it can be separated to form argon products. At least a portion of the nitrogen-rich light component stream can be recycled to the ammonia synthesis reactor. The nitrogen-lean light component stream can be separated to produce a hydrogen-rich light component stream and a helium-rich light component stream. The nitrogen-lean light component stream can be separated using any combination of membranes (such as palladium membranes), electrochemical processes (such as applying voltage to an electrochemical hydrogen pump / compressor), and / or cryogenic distillation. Separating the nitrogen-lean light component stream may include a step in which the nitrogen-lean light component stream or a stream derived from the nitrogen-lean light component stream is contacted with an adsorbent at a temperature below 30 K. Using the adsorbent at a temperature below 30 K can produce a helium-rich light component stream with a helium purity greater than 99.999%. The adsorbent can be regenerated using an electric heater or an internal coil with a flowing fluid at a temperature of 100 to 300 K. Retained impurities (such as hydrogen) can be recycled to the ammonia synthesis reactor. Retained impurities can also be recycled to a compressor upstream of the ammonia synthesis reactor. When both the first light component stream and the lean nitrogen light component stream are separated using cryogenic distillation and / or partial condensation, these two processes can be integrated into a single heat exchange network. The hydrogen-rich light component stream can be recycled to the ammonia synthesis reactor and can be compressed as needed. The hydrogen-rich light component stream can be recycled to the purified feed stream and can be compressed as needed. The helium-rich light component stream can be further purified, such as by reacting hydrogen impurities with oxygen followed by adsorption, to form helium products. Depending on the separation method used for the lean nitrogen light component stream and the end-user specifications of the helium products, the helium-rich light component stream can have sufficiently high purity to form helium products.

[0045] The hydrogen feed stream can be used to react with precursors to produce a hydrogen support, such as methylcyclohexane (MCH) via the hydrogenation of toluene. MCH can then be stored and / or transported in a dense liquid phase at a lower cost than gaseous hydrogen, and dehydrogenated at the endpoint to recover hydrogen. An ammonia synthesis reactor can be considered a hydrogenation reactor, where nitrogen is the precursor and ammonia is the hydrogen support. Hydrogenation and / or dehydrogenation reactions may require a catalyst. Any suitable compound can be chosen as the precursor, readily hydrogenated to form a hydrogen support readily dehydrogenated to recover hydrogen. Aromatic hydrocarbons and other unsaturated hydrocarbons can be used as suitable precursors. The hydrogenation reaction can be carried out at elevated temperatures and pressures to produce a reactor effluent containing unreacted precursors and hydrogen, the hydrogen support, and unreacted impurities from the hydrogen feed stream. The reactor effluent can be cooled to reduce the vapor pressure of the precursors and hydrogen support. The reactor effluent can be separated to produce a first hydrogen-rich support liquid stream and a reactor overhead effluent stream. The second hydrogen-rich carrier liquid stream can be recovered from the reactor effluent by cooling and / or washing with a stream of liquid water, resulting in a first light component stream with negligible concentrations of precursor and hydrogen carrier. If helium is present in the hydrogen feed stream, the high hydrogen conversion rate in the feed stream can lead to a significant helium concentration in the first light component stream. Similar to ammonia production, helium and hydrogen separation can be achieved using any combination of membrane, adsorption, absorption, and cryogenic separation methods to form a helium product and a hydrogen recycle stream to be returned to the hydrotreating reactor.

[0046] Figure 1This is a schematic diagram depicting one embodiment of a hydrogen purification process according to one or more aspects of this disclosure. A natural hydrogen feed stream 101 enters one or more membrane stages 110, thereby producing a permeate stream 111 enriched with methane, argon, and nitrogen, and a permeate stream 112 enriched with helium and hydrogen. Carbon dioxide and water can be removed from the permeate stream using a TSA 120, and the resulting purified permeate stream 121 is separated in a CH4 / N2 / Ar recovery section 130 to produce, as needed, methane 131, nitrogen 132, and argon 133 products, and a hydrogen-helium mixture 134, which can be combined with the permeate stream 112, or compressed in a recirculating compressor 135 and recycled to one or more membrane stages 110. The permeate stream 112 is compressed as needed to feed to a hydrogen PSA 140, thereby producing a PSA product stream 141 enriched with hydrogen and helium, and a PSA tail stream 142 enriched with methane, argon, carbon dioxide, water vapor, and nitrogen. PSA tail stream 142 can be recycled to one or more membrane stages 110. The PSA product stream 141 can then be cooled and fed to a cryogenic hydrogen purifier 150. Using a cryogenic separation system including one or more flash separators and / or distillation columns, the cryogenic hydrogen purifier 150 can produce a first hydrogen product stream 151, a cryogenic hydrogen purifier tail stream 152 that can be recycled to one or more membrane stages 110, and a hydrogen-helium column overhead stream 153. The cryogenic hydrogen purifier 150 can be integrated with the CH4 / N2 / Ar recovery section 130 by sharing a single insulated cold box, merging into a single multi-stream heat exchanger, and / or sharing a cooling utility 154. The hydrogen-helium column overhead stream 153 can then be separated in a hydrogen removal step 160, which can produce a second hydrogen product stream 161, a hydrogen removal tail stream 162 that can be recycled to one or more membrane stages 110, and / or a crude helium stream 163. The crude helium stream 163 can be purified in a helium PSA 170 to produce a helium product stream 171 and a helium PSA tail stream 172 that can be recycled to one or more membrane stages 110.

[0047] Figure 2Another embodiment is shown, which utilizes three membrane stages (210A, 210B, 210C) arranged such that each subsequent stage receives permeate from the preceding stage. The hydrogen concentration in each subsequent permeate stream is low, such that the first permeate stream 211 and the second permeate stream 212 are combined and fed into the hydrogen PSA 240, and the third permeate stream 213 is compressed and recycled back to the first membrane stage feed. The third permeate stream 214 can be reinjected into a suitable subsurface formation 215 or sent to the CH4 / N2 / Ar recovery section 230 to produce methane 231, nitrogen 232, and argon 233 products as needed. The PSA product stream 241 can then be cooled and further purified in the CTSA 250 to produce a hydrogen-helium mixture 251. When the CTSA is regenerated, the waste regeneration gas 252 can be compressed in the regeneration compressor 255 and used in the purging step of the hydrogen PSA 240 to increase hydrogen recovery. It is then combined with the third permeate stream 213, compressed in the recirculation compressor 235, and recycled as a recirculation stream 236 to the first membrane stage 210A. The water stream 237 can be condensed and separated in the recirculation compressor 235, for example, in a cooler after the compression stage. Additional recirculation streams can be compressed in the recirculation compressor 235, such as the tail gas stream 238 purified downstream of the helium stream. The hydrogen-helium mixture 251 can then be separated in the cryogenic hydrogen purifier 260, such as... Figure 1 As shown, this is to produce a helium-rich hydrogen-helium mixture 261 and a first hydrogen product stream 262. Figure 2 The final hydrogen-helium separation step is an electrochemical hydrogen pump / compressor 270, which produces a helium product stream 271 and a second hydrogen product stream 272. The second hydrogen product stream 272 may need to be dehydrated in a dehydration unit 280 before it can be combined with the first hydrogen product stream 262 exiting the cryogenic hydrogen purifier 260 to form a combined hydrogen product stream 273. In at least some embodiments, the hydrogen stream can be recycled to any point (not shown) upstream of the hydrogen PSA 240 to eliminate the need for the dehydration unit 280.

[0048] Figure 3 It shows Figure 2 A variation thereof, wherein the hydrogen feed stream 301 is at a sufficiently high hydrogen concentration to allow direct entry into the hydrogen PSA 340. Two membrane stages (310A, 310B) may be required (where the first permeate stream is fed to the second membrane stage 310B) to recycle the tail gas stream from the downstream process. The first permeate stream 311 can be compressed in the permeate compressor 315 before being combined with the hydrogen feed stream 301. The second permeate stream 312 can be compressed in the recirculation compressor 235 and recirculated to the first membrane stage 310A. At least a portion of the recirculated stream 236 can be reinjected into a suitable subsurface formation 339.

[0049] Figure 4A It shows Figure 2 and Figure 3 An alternative to hydrogen-helium separation involves burning a helium-rich hydrogen-helium mixture 261 in a generator 410 with an oxidant 402 (such as air, oxygen, or oxygen-enriched air) to generate electricity and / or heat 411. Flue gas 412 exiting the generator can be cooled in a heat exchanger 420 and compressed in a compressor 430. Water can be condensed and removed in one or two steps (421, 431). The cooled and compressed flue gas 432 can then be separated in a helium PSA 440 to produce a helium product stream 441, which can be recycled to... Figure 2 The helium PSA exhaust gas flow 238 of the circulating compressor 235 in the middle.

[0050] Figure 4B It shows Figure 2 and Figure 3 An alternative to hydrogen-helium separation in which the hydrogen-helium mixture is catalytically oxidized using deoxygenation catalyst 450.

[0051] Figure 5 A helium recovery process is illustrated, in which a hydrogen feedstock is first combusted to generate electricity, and helium is recovered from the combustion products. In a generator 510, a natural hydrogen feedstream 501 is first combusted with an oxidant 502 (such as air, oxygen, or oxygen-enriched air) to generate electricity and / or heat 511. The flue gas 512 can then be cooled in a heat exchanger 520 and compressed in a compressor 530, with water optionally removed in one or two steps (521, 531), as... Figure 4A and Figure 4B As shown. The cooled and compressed flue gas 532 can then enter one or more membrane stages (540A, 540B). When as... Figure 5 When using two membrane stages, a helium-rich first permeate stream 541, a second permeate stream 542, and a helium-depleted residual stream 543 are generated. The first permeate stream 541 can then be purified in a helium PSA 550 to produce a helium product stream 551 and a helium PSA tail stream 552 that can be discharged or compressed and recycled to the first membrane stage 540A. The second permeate stream 542 can be compressed in a permeate compressor 560 and recycled to the first membrane stage 540A to improve total helium recovery. The residual stream 543 can be expanded in an expander 560 to generate electricity, which can be used to provide at least a portion of the power required to compress the helium PSA tail stream 552. Carbon dioxide from the flue gas can be captured and utilized or sequestered.

[0052] Figure 6 This is a schematic diagram of a tail gas separation process, in which methane, nitrogen, and / or argon are recovered from the tail gas stream, allowing the recycling of the remaining hydrogen-helium mixture. Residual stream 611 (which can be equivalent to...) can be removed in the TSA 620. Figure 1 Stream 111 or Figure 2 or Figure 3Carbon dioxide and / or water vapor in stream 214 are used to prevent freezing at low temperatures. The treated permeate stream 621 can then be cooled in heat exchanger 630 by exchanging heat with the returned product stream and liquid nitrogen 623 (if necessary, liquid nitrogen 623 will exit heat exchanger 630 as at least partially vaporized nitrogen 624). Hydrogen product stream 625 (which may be equivalent to...) Figure 1 The first hydrogen product stream 151 and / or the second hydrogen product stream 161, or Figure 2 or Figure 3 The first hydrogen product stream 262 and / or the second hydrogen product stream 272 can also be cooled in heat exchanger 630 and further purified in cryogenic TSA 640. The cooled permeate stream 631 can be separated in the first distillation column 650 to produce a second hydrogen-helium column overstream 651, which can be heated in heat exchanger 630 and recycled to… Figure 1 The hydrogen-helium mixture 151, or Figure 2 or Figure 3 251 or Figure 2 or Figure 3 The helium-rich hydrogen-helium mixture 261 is present. The first bottom stream 652 from the first distillation column 650 can then enter the second distillation column 660 to produce a nitrogen-rich second overhead stream 661, which can be heated in the heat exchanger 630 and used to regenerate TSA 620. The second bottom stream 662 from the second distillation column 660 can then enter the third distillation column 670 to produce an argon-rich overhead stream 671 and a methane-rich third bottom stream 672. The nitrogen-rich second overhead stream 661, the argon-rich overhead stream 671, and the methane-rich third bottom stream 672 can then be heated in the heat exchanger 630 and sold, discharged, flared, or re-injected as needed.

[0053] Figure 7 This is a schematic diagram of a cryogenic hydrogen purifier according to one or more aspects of this disclosure. A first heat exchanger 710 cools the PSA product stream 707, which can be equivalent to... Figure 1 PSA product stream 141 or Figure 2 or Figure 3 The PSA product stream 251 is located in the process. Cooling load can be provided by reheating the stream from the downstream process and / or liquid nitrogen 708, which can exit as at least partially vaporized nitrogen 709. Impurities can be removed in CTSA 720 to produce a hydrogen-helium mixture 721. When CTSA 720 is regenerated, the waste regeneration gas 722 can be recycled to… Figures 1 to 3One or more membranes from any of the following can be used. The hydrogen-helium mixture 721 can then be further cooled and partially condensed in a second heat exchanger 730. The cooling load can be provided by reheating the stream and / or liquid hydrogen from the downstream process. Liquid hydrogen can be obtained from an on-site hydrogen liquefaction unit (not shown). The partially condensed hydrogen-helium mixture 731 can then be separated in a flash tank 740 to produce a helium-rich overhead stream 741 and a hydrogen-rich understream stream 742. The helium-rich overhead stream 741 can then be reheated to ambient temperature in the second heat exchanger 730 and the first heat exchanger 710 to provide the cooling load. Any residual hydrogen impurities can be removed from the heated helium-rich overhead stream 743, for example, by reacting it with an oxidant 744 (such as air) on a deoxygenation catalyst 750, to produce a crude helium stream 751. The crude helium stream 751 can enter a helium PSA 760 to produce a pure helium product 761. The lean helium tail stream 762 can be compressed and recycled to Figures 1 to 3 One or more membranes from any of the following methods. At least a portion of the heated helium-rich overhead stream 743 may be compressed (if desired) in the circulating compressor 745 and combined with the hydrogen-helium mixture 707 to increase the helium concentration in the stream entering CTSA 720. The hydrogen-rich understream stream 742 may be depressurized and fed to the stripping column 770. The reboiler of the stripping column 770 may be heated by the second heat exchanger 730. Helium may be stripped from the hydrogen-rich understream stream 742 to produce a liquid hydrogen product stream 771, which may be depressurized to provide more cooling load in the second and first heat exchangers. If the stripping column operates at a lower pressure, the hydrogen-rich understream stream 771 may be pumped and then vaporized at a higher pressure. In at least some embodiments, the hydrogen-rich understream stream 771 may be pumped to a pressure such that, after heating in the second heat exchanger 730 and the first heat exchanger 710, the resulting hydrogen product stream 772 is at a desired pressure for utilization, transport, or storage. In at least some embodiments, at least a portion of the hydrogen-rich column bottom stream 771 can be diverted and combined with an optional liquid hydrogen stream 773 (if additional refrigeration is required), heated in a second heat exchanger 730 and a first heat exchanger 710, compressed in a hydrogen product compressor 775, and combined with a hydrogen product stream 772. A second hydrogen-helium mixture 776 exits the top of the stripping column and can be reheated in the second heat exchanger 730 and the first heat exchanger 710, compressed in a recirculating compressor 745 (if required), and recycled to the PSA product stream 707. The first heat exchanger 710 and the second heat exchanger 730 can be combined in a single multi-stream heat exchanger.

[0054] Figure 8 yes Figure 7A schematic diagram of a variant that produces liquid hydrogen products. A partially condensed hydrogen-helium mixture 731 is passed through an OP catalyst 840, which catalyzes the conversion of orthohydrogen to secondary hydrogen to produce a secondary hydrogen-rich hydrogen-helium mixture 836. This mixture can then be depressurized and separated in a first intermediate-pressure flash evaporator 840 to produce a first intermediate-pressure vapor stream 841 and a first intermediate-pressure liquid stream 842. The first intermediate-pressure liquid stream 842 can then be depressurized and separated in an intermediate-pressure flash evaporator 850 to produce an intermediate-pressure vapor stream 851 and an intermediate-pressure liquid stream 852. The intermediate-pressure vapor stream 851 can be heated in a second heat exchanger 730 and a first heat exchanger 710, and compressed in a circulating compressor 855 to produce a circulating stream 856. The circulating stream 856 can be cooled in the first heat exchanger 710 and the second heat exchanger 730, depressurized, and fed into the first intermediate-pressure flash evaporator 840. At least a portion of the circulating stream 856 can be diverted to form a refrigerated stream 857. The refrigerated stream 857 can be expanded in the expander 865 and heated in the second heat exchanger 730 and / or the first heat exchanger 710, then returned to the recycle compressor 855. The intermediate-pressure liquid stream 852 can then be depressurized and separated in the low-pressure flash evaporator 860 to produce a low-pressure vapor stream 861 and a low-pressure liquid stream 862. The low-pressure vapor stream 861 can be heated in the second heat exchanger 730 and the first heat exchanger 710 and compressed in the recycle compressor 855 for recirculation. The low-pressure liquid stream 862 can be extracted as a liquid hydrogen product. The first intermediate-pressure vapor stream 841 can be cooled by indirect heat exchange in the intermediate-pressure flash evaporator 850 and the low-pressure flash evaporator 860 to produce a partially condensed intermediate-pressure stream 863. The partially condensed intermediate-pressure stream 863 can then be separated in the second intermediate-pressure flash evaporator 870 to produce a second intermediate-pressure vapor stream 871 and a second intermediate-pressure liquid stream 872. The second medium-pressure vapor stream 871 is enriched with helium and can be heated in the second heat exchanger 730 and the first heat exchanger 710 to generate a heated helium-rich overhead stream 843, which can be used as follows: Figure 7 Purification is performed as shown.

[0055] Figure 9 yes Figure 8 A schematic diagram of a variant, in which intermediate flash evaporation is omitted. The first intermediate-pressure liquid flow 842 can be combined with the second intermediate-pressure liquid flow 872, depressurized, and fed into the low-pressure flash evaporator 860. In an alternative embodiment (not shown), the first intermediate-pressure liquid flow 842 and the second intermediate-pressure liquid flow 872 can be depressurized and fed into the low-pressure flash evaporator 860, respectively.

[0056] Figure 10 yes Figure 9A schematic diagram of a variant, wherein the first intermediate-pressure flash evaporator is replaced by an intermediate-pressure distillation column. The hydrogen-helium mixture 836 rich in intermediate hydrogen can be depressurized and separated in the intermediate-pressure distillation column 1040. The second intermediate-pressure liquid stream 872 can enter the intermediate-pressure distillation column 1040 at the same location as the hydrogen-helium mixture 836, or it can be fed at a higher or lower location as needed. The intermediate-pressure distillation column 1040 can employ trays and / or packing as needed to improve helium and hydrogen separation. The overhead stream 1041 can be cooled by indirect heat exchange in the low-pressure flash evaporator 860. The bottom stream 1042 can be depressurized and fed into the low-pressure flash evaporator 860. The reboiler circulating stream 1043 can be heated and at least partially boiled in the second heat exchanger 730, and then returned to the intermediate-pressure distillation column 1040. The distillation column can also be replaced with... Figure 8 In the first intermediate-pressure flash evaporator, the bottom stream is fed into the intermediate-pressure flash evaporator 850, and the top stream is cooled by indirect heat exchange in the intermediate-pressure flash evaporator 850.

[0057] Figure 11 yes Figure 8 A schematic diagram of a variant, in which the first intermediate-pressure flash evaporator is omitted. The hydrogen-helium mixture 836 rich in secondary hydrogen can be cooled by indirect heat exchange in the intermediate-pressure flash evaporator 850 and the low-pressure flash evaporator 860 to produce a subcooled liquid stream 1163. The circulating stream 856 can be cooled, depressurized, and / or combined with the hydrogen-helium mixture 836 rich in secondary hydrogen, a partially condensed hydrogen-helium mixture 731 (not shown), or the subcooled intermediate-pressure liquid stream 1163 (not shown), or separately depressurized and fed to the intermediate-pressure flash evaporator 1170 (not shown). The subcooled liquid stream 1163 can be depressurized and fed to the intermediate-pressure flash evaporator 1170. The intermediate-pressure liquid stream 1172 can then be depressurized and fed to the intermediate-pressure flash evaporator 850. In at least some embodiments, the intermediate-pressure flash evaporator 1170 can be replaced by a distillation column. The distillation column can use a second heat exchanger 730 to provide the reboiler heating load, such as Figure 10 As shown.

[0058] Figure 12This is a schematic diagram of a process for producing ammonia from a hydrogen feed stream containing helium impurities. A pretreatment TSA 1210 removes CO2 and H2O from the hydrogen feed stream 1201 to produce a partially purified feed stream 1211. A liquid nitrogen scrubber 1220 contacts the partially purified feed stream 1211 with a liquid nitrogen stream 1231 to remove other impurities (such as methane) and produce a purified feed stream 1221 containing hydrogen and nitrogen, and a waste wash stream 1222. An air separation unit 1230 can supply the liquid nitrogen stream 1231. The purified feed stream 1221 can be combined with the nitrogen stream 1232 from the air separation unit 1230 to produce a medium-pressure synthetic ammonia feed stream 1234, which can be compressed as needed in a synthetic ammonia feed compressor 1235 to produce a synthetic ammonia feed stream 1237. The wastewater scrubbing stream 1222 can be vaporized and used for regeneration pretreatment TSA 1210, and can be discharged or flared as needed. The ammonia feed stream 1237 can then be reacted in the ammonia synthesis reactor 1240 in the presence of a catalyst to produce an ammonia-enriched reaction product stream 1241. The reaction product stream 1241 can then be cooled in a heat exchanger 1245 to condense at least a portion of the ammonia. The partially condensed reaction product stream 946 can be separated in an ammonia condenser 1250 to produce a first ammonia product 1251 and an ammonia condenser overhead stream 1252, which can be heated in the heat exchanger 1245 to provide at least a portion of the cooling required to cool the reaction product stream 1241. The heated ammonia condenser overhead stream 1253 can be diverted into a first recirculation stream 1254 and an ammonia scrubbing tower feed stream 1256, the first recirculation stream being returned to the ammonia synthesis reactor 1240 and the ammonia scrubbing tower feed stream being fed into an ammonia scrubbing tower 1260. The ammonia scrubber further recovers ammonia from the ammonia scrubber feed stream 1256, for example, by stripping with a high-pressure water stream to produce a second ammonia product 1261 and a first light component stream 1262. The first light component stream 1262 can be separated using a single-stage or multi-stage membrane 1270 to produce a nitrogen-rich light component stream 1271 and a nitrogen-lean light component stream 1272. The nitrogen-rich light component stream 1271 can be vented to purge inert components (such as argon) from the system that would otherwise accumulate. If commercially relevant amounts of argon are present in the nitrogen-rich light component stream 1271, further separation can be performed to recover argon (not shown). The nitrogen-lean light component stream 1272 can then be separated in a hydrogen-helium separator 1280 to produce a hydrogen-rich light component stream 1281 and a helium-rich light component stream 1282. The hydrogen-helium separator 1280 can include any combination of membranes, electrochemical processes, and / or cryogenic distillation. The hydrogen-rich light component stream 1281 can be recycled to the ammonia synthesis feed compressor 1235 and / or, after compression as needed, to the first recycle stream 1254. Any hydrogen impurities can be removed from the helium-rich light component stream 1282 by reacting it with an oxidant 1283 (such as air) on a deoxygenation catalyst 1285 to produce a crude helium stream 1286.The crude helium stream 1286 can be purified in helium PSA 1290 to produce pure helium product 1291 and helium PSA tail stream 1292. PSA tail stream 1292 can be recycled to ammonia synthesis reactor 1240 (not shown).

[0059] Figure 13 yes Figure 12 A schematic diagram of a variant is shown, in which a hydrogen PSA is used to purify the hydrogen feed stream. In at least some embodiments, particularly when the methane content in the hydrogen feed stream 1201 is low, the hydrogen PSA 1320 can separate the hydrogen feed stream 1201 to produce a purified feed stream 1221 and a hydrogen tail stream 1312. The air separation unit 1230 provides only gaseous nitrogen 1232 to be combined with the purified feed stream 1221, thereby producing a medium-pressure synthetic ammonia feed stream 1234. In at least some embodiments, the crude helium stream 1282 exiting the hydrogen-helium separator 1280 can have sufficient purity downstream for use without further purification.

[0060] Figure 14 yes Figure 12A schematic diagram of a variant in which a hydrogen feed stream reacts with a precursor to form a hydrogen support. The hydrogen feed stream may contain helium impurities. In at least some embodiments, the precursor is toluene, and the hydrogen support is methylcyclohexane (MCH). The purified feed stream 1421 containing hydrogen can be compressed in a hydrogenation reactor feed compressor 1435 and combined with the precursor 1430 (which may be pumped if desired) to form a hydrogenation reactor feed stream 1437. In the hydrogenation reactor 1440, hydrogen reacts with the precursor to form a hydrogen support, thereby producing a hydrogenation reactor effluent 1441 enriched with the hydrogen support and depleted in both the precursor and hydrogen. The hydrogenation reactor effluent 1441 can be cooled in a heat exchanger 1445 to reduce the amount of precursor and hydrogen support in the gas phase of the cooled hydrogenation reactor effluent 1446. The cooled hydrogen reactor effluent 1446 is then separated in the hydrogenation reactor effluent separator 1450 to form a hydrogen-rich carrier liquid 1451 and a hydrogen reactor overhead effluent 1452. The hydrogen reactor overhead effluent 1452 can provide cooling to the heat exchanger 1445. At least a portion of the heated hydrogen reactor overhead effluent 1453 can be diverted to form a first recirculation stream 1454 containing unreacted hydrogen, which can be compressed and returned to the hydrogenation reactor 1440. In at least some embodiments, the first recirculation stream 1454 can be recycled to the hydrogenation reactor feed compressor 1435. At least a portion of the heated hydrogen reactor overhead effluent 1453 can be diverted to form a scrubbing tower feed stream 1456. A second hydrogen-rich carrier liquid 1461 can be recovered from the scrubbing tower feed stream 1456 in the scrubbing tower 1460, for example, by washing with high-pressure water followed by stripping. The remaining gas exits the scrubbing tower 1460 as a first light component stream 1472 containing helium and hydrogen. In at least some embodiments, the concentrations of precursors and hydrogen carriers in the heated hydrogen reactor overhead effluent 1453 are low enough that a scrubbing tower can be omitted, and the scrubbing tower feed stream 1456 can form the first light component stream 1472 (not shown). This can be as follows: Figure 12 The first light component stream 1472 is separated to produce a hydrogen-rich light component stream 1281, a helium product 1291, and a helium PSA tail stream 1292.

[0061] Aspect 1: A method comprising partially condensing and separating a feed stream containing helium and hydrogen to generate a first medium-pressure vapor stream and a first medium-pressure liquid stream; depressurizing the first medium-pressure liquid stream or a stream derived from the first medium-pressure liquid stream to generate a low-pressure vapor stream and a low-pressure liquid stream; cooling the first medium-pressure vapor stream by indirect heat exchange with the low-pressure liquid stream to generate a first partially condensed medium-pressure stream; and separating the first partially condensed medium-pressure stream to generate a second medium-pressure vapor stream and a second medium-pressure liquid stream.

[0062] Aspect 2: According to the method of aspect 1, the low-pressure liquid flow contains more than 97% H2 by volume.

[0063] Aspect 3: According to the method of aspect 1 or 2, the partial condensation of the feed stream includes cooling the feed stream and depressurizing the feed stream.

[0064] Aspect 4: The method according to any one of Aspects 1 to 3, wherein the partial condensation of the feed stream further comprises a reaction that catalyzes the formation of secondary hydrogen from the positive hydrogen in the feed stream.

[0065] Aspect 5: The method according to any one of Aspects 1 to 4, the method further comprising depressurizing the first intermediate-pressure liquid flow to generate an intermediate-pressure vapor flow and an intermediate-pressure liquid flow; depressurizing the intermediate-pressure liquid flow to generate the low-pressure vapor flow and the low-pressure liquid flow; and cooling the first intermediate-pressure vapor flow by heat exchange with the intermediate-pressure liquid flow.

[0066] Aspect 6: According to the method of aspect 5, the method further includes compressing the intermediate pressure vapor stream to generate a compressed intermediate pressure vapor stream; heating the compressed intermediate pressure vapor stream to generate an intermediate pressure circulating stream; and merging the intermediate pressure circulating stream with the feed stream before separating to form the first intermediate pressure vapor stream and the first intermediate pressure liquid stream.

[0067] Aspect 7: The method according to any one of aspects 1 to 6, the method further comprising contacting the second medium-pressure liquid flow with the first medium-pressure vapor flow.

[0068] Aspect 8: The method according to any one of aspects 1 to 7, the method further comprising merging the second medium-pressure liquid flow with the first medium-pressure liquid flow.

[0069] Aspect 9: The method according to any one of Aspects 1 to 8, the method further comprising compressing the low-pressure steam stream to generate a compressed low-pressure steam stream; heating the compressed low-pressure steam stream to generate a low-pressure circulating stream; and merging the low-pressure circulating stream with the feed stream before separating to form the first medium-pressure steam stream and the first medium-pressure liquid stream.

[0070] Aspect 10: A method comprising cooling a feed stream containing helium and hydrogen to produce a subcooled hydrogen-helium mixture; depressurizing and separating the subcooled hydrogen-helium mixture or a stream derived from the subcooled hydrogen-helium mixture to produce a medium-pressure vapor stream and a medium-pressure liquid stream; and depressurizing the medium-pressure liquid stream or a stream derived from the medium-pressure liquid stream to produce a low-pressure vapor stream and a low-pressure liquid stream; wherein at least a portion of the cooling load for cooling the feed stream originates from cooling provided through indirect heat exchange with the low-pressure liquid stream.

[0071] Aspect 11: The method according to aspect 10, wherein the low-pressure liquid flow comprises more than 97% H2 by volume.

[0072] Aspect 12: The method according to aspect 10 or 11, the method further comprising compressing the low-pressure vapor stream to generate a compressed low-pressure vapor stream; heating the compressed low-pressure vapor stream to generate a low-pressure circulating stream; and combining the low-pressure circulating stream with the supercooled hydrogen-helium mixture before separating to form the medium-pressure vapor stream and the medium-pressure liquid stream.

[0073] Aspect 13: The method according to any one of Aspects 10 to 12, the method further comprising depressurizing the subcooled intermediate-pressure liquid stream to generate an intermediate-pressure vapor stream and an intermediate-pressure liquid stream; and depressurizing the intermediate-pressure liquid stream to generate the low-pressure vapor stream and the low-pressure liquid stream; wherein at least a portion of the cooling load for cooling the feed stream originates from cooling provided through indirect heat exchange with the intermediate-pressure liquid stream.

[0074] Aspect 14: The method according to aspect 13, the method further comprising compressing the intermediate pressure vapor stream to generate a compressed intermediate pressure vapor stream; heating the compressed intermediate pressure vapor stream to generate an intermediate pressure circulating stream; and combining the intermediate pressure circulating stream with the supercooled hydrogen-helium mixture before separating to form the intermediate pressure vapor stream and the intermediate pressure liquid stream.

[0075] Aspect 15: The method according to any one of Aspects 10 to 14, the method further comprising catalyzing a reaction in which positive hydrogen in the feed stream is formed into secondary hydrogen prior to cooling to produce a supercooled medium-pressure flow.

[0076] Aspect 16: A method for producing ammonia from a synthetic ammonia feed stream containing hydrogen, nitrogen, and helium, the method comprising reacting hydrogen and nitrogen in the synthetic ammonia feed stream to produce a crude ammonia stream; partially condensing and separating the crude ammonia stream to produce a first ammonia product stream and an ammonia condenser overhead stream; separating at least a portion of the ammonia condenser overhead stream to produce a second ammonia product stream and a first light component stream; separating the first light component stream to produce a nitrogen-rich light component stream and a nitrogen-lean light component stream; separating the nitrogen-lean light component stream to produce a hydrogen-rich light component stream and a helium-rich light component stream; and combining the hydrogen-rich light component stream with the synthetic ammonia feed stream.

[0077] Aspect 17: The method according to aspect 16, the method further comprising contacting a hydrogen feed stream containing helium, hydrogen and one or more impurities with a liquid nitrogen stream to produce a purified feed stream depleted of the one or more impurities and a waste liquid nitrogen stream enriched with the one or more impurities; wherein the ammonia synthesis feed stream comprises the purified feed stream.

[0078] Aspect 18: The method according to aspect 16 or 17, wherein the first light component stream is separated by selectively permeating the nitrogen-poor light component stream through a membrane.

[0079] Aspect 19: The method according to any one of Aspects 16 to 18, wherein separating the nitrogen-poor light component stream comprises contacting the nitrogen-poor light component stream or a stream derived from the nitrogen-poor light component stream with an adsorbent at a temperature below 30 K.

[0080] Aspect 20: The method according to aspect 19 further includes regenerating the adsorbent with regenerated gas to generate waste regenerated gas; and merging the waste regenerated gas with the synthetic ammonia feed stream.

[0081] Aspect 21: A method comprising reacting a purified feed stream containing hydrogen and helium with a precursor to produce a hydrogenation reactor effluent containing a hydrogen carrier; separating the hydrogenation reactor effluent to produce a liquid stream enriched with the hydrogen carrier and a hydrogenation reactor overhead effluent; separating the hydrogenation reactor overhead effluent or a stream derived from the hydrogenation reactor overhead effluent to produce a hydrogen-rich light component stream and a helium-rich light component stream; and combining the hydrogen-rich light component stream with the hydrogenation reactor feed stream.

[0082] Aspect 22: According to the method of aspect 21, the method further includes contacting a hydrogen feed stream containing helium, hydrogen, and one or more impurities with a liquid nitrogen stream to produce a purified feed stream leaning against the one or more impurities and a waste liquid nitrogen stream enriched with the one or more impurities; wherein the overhead effluent from the hydrogenation reactor is separated to produce a nitrogen-rich light component stream and the nitrogen-lean light component stream before separating the nitrogen-lean light component stream to produce the hydrogen-rich light component stream and the helium-rich light component stream.

[0083] Aspect 23: According to the method of aspect 22, wherein the overhead stream from the hydrogenation reactor is separated by selectively permeating the nitrogen-poor light component stream through a membrane.

[0084] Aspect 24: The method according to aspect 22 or 23, wherein the separation of the nitrogen-poor light component stream comprises contacting the nitrogen-poor light component stream or a stream derived from the nitrogen-poor light component stream with an adsorbent at a temperature below 30 K.

[0085] Aspect 25: The method according to aspect 24 further includes regenerating the adsorbent to generate waste regenerated gas; and combining the waste regenerated gas with the purified feed stream.

[0086] Example 1

[0087] Using Aspen Plus® process simulation software available from Aspen Technology Inc. Figure 7The process was simulated by computer. A summary of the selected stream data can be found in Table 1. The PSA product stream 707, containing approximately 99% H2 and 1% He by volume, was cooled, partially condensed, and separated to produce a helium-rich overhead stream 741 containing more than 63% He by volume. The hydrogen in the helium-rich overhead stream 741 was consumed by reacting with air, and the resulting water, nitrogen, and unreacted oxygen were removed by adsorption. The hydrogen-rich liquid stream 742 was purified in a stripping column 770 to a purity greater than 99.99% H2 by volume.

[0088] Table 1

[0089]

[0090] Example 2

[0091] Using Aspen Plus® process simulation software available from Aspen Technology Inc. Figure 8 The process was simulated using a computer. A summary of the selected flow data can be found in Table 2. Figure 7 Compared to the previous process, a higher purity helium was obtained in the second medium-pressure flash evaporator 870 due to the lower temperature achieved by further cooling through heat exchange with the intermediate-pressure and low-pressure liquid streams. The added cooling in the process also allowed for the extraction of liquid hydrogen products, also with a purity greater than 99.99% by volume.

[0092] Table 2

[0093]

[0094] Example 3

[0095] Using Aspen Plus® process simulation software available from Aspen Technology Inc. Figure 9The process was simulated by computer. A summary of the selected stream data can be found in Table 3. The hydrogen feed stream 901 contains CO2 and H2O impurities that must be removed by TSA, methane impurities that must be partially removed by liquid nitrogen washing, and 0.9% by volume of potentially valuable helium byproducts. This is higher than the helium concentration found in typical hydrogen streams produced by natural gas steam methane reforming, which typically contains less than about 100 ppmv of helium. The ammonia feed stream 937 contains a stoichiometric mixture of hydrogen and nitrogen, and less than 1% by volume of methane, argon, and helium. Note that the helium content in the first light component stream 962 has been concentrated to more than 7% by volume. Argon and methane are also concentrated in the first light component stream 962 and partially removed in one or more membranes 970. Partial condensation produces a helium-rich light component stream of 65% by volume and a hydrogen-rich light component stream of 99.5% by volume. Helium recovery was incorporated downstream of the ammonia synthesis reactor, utilizing the concentration of helium in the first light component stream to reduce the size of helium recovery equipment typically located on the natural gas stream upstream of a typical ammonia synthesis reactor.

[0096] Table 3

[0097]

[0098] While the principles of the invention have been described above in conjunction with preferred embodiments, it is to be clearly understood that this description is by way of example only and is not intended to limit the scope of the invention.

Claims

1. A method, the method comprising: Partial condensation and separation of the feed stream containing helium and hydrogen to produce a first medium-pressure vapor stream and a first medium-pressure liquid stream; The pressure of the first medium-pressure liquid flow or the flow originating from the first medium-pressure liquid flow is reduced to generate a low-pressure vapor flow and a low-pressure liquid flow; The first medium-pressure vapor stream is cooled by indirect heat exchange with the low-pressure liquid stream to produce a first partial condensation of the medium-pressure stream; as well as The first portion of the condensed medium-pressure flow is separated to generate a second medium-pressure vapor flow and a second medium-pressure liquid flow.

2. The method of claim 1, wherein the low-pressure liquid stream comprises more than 97% H2 by volume.

3. The method of claim 1, wherein the partial condensation of the feed stream comprises cooling the feed stream and depressurizing the feed stream.

4. The method of claim 1, wherein the partial condensation of the feed stream further comprises a reaction that catalyzes the formation of secondary hydrogen from the positive hydrogen in the feed stream.

5. The method according to claim 1, further comprising depressurizing the first intermediate-pressure liquid flow to generate an intermediate-pressure vapor flow and an intermediate-pressure liquid flow; Depressurize the intermediate-pressure liquid flow to generate the low-pressure vapor flow and the low-pressure liquid flow; and The first medium-pressure steam stream is cooled by heat exchange with the medium-pressure liquid stream.

6. The method of claim 5, further comprising compressing the intermediate pressure steam stream to generate a compressed intermediate pressure steam stream; Heating the compressed intermediate-pressure vapor stream to generate an intermediate-pressure circulating stream; and Before separating to form the first intermediate-pressure steam flow and the first intermediate-pressure liquid flow, the intermediate-pressure circulating flow is combined with the feed flow.

7. The method according to claim 1, further comprising contacting the second medium-pressure liquid flow with the first medium-pressure vapor flow.

8. The method according to claim 1, further comprising merging the second medium-pressure liquid flow with the first medium-pressure liquid flow.

9. The method of claim 1, further comprising compressing the low-pressure steam stream to generate a compressed low-pressure steam stream; Heating the compressed low-pressure steam stream to generate a low-pressure circulating stream; and The low-pressure circulating flow is combined with the feed flow before being separated to form the first medium-pressure steam flow and the first medium-pressure liquid flow.

10. A method, the method comprising: Cooling the feed stream containing helium and hydrogen to produce a supercooled hydrogen-helium mixture; The supercooled hydrogen-helium mixture or a stream derived from the supercooled hydrogen-helium mixture is depressurized and separated to produce a medium-pressure vapor stream and a medium-pressure liquid stream; as well as The medium-pressure liquid flow or the flow originating from the medium-pressure liquid flow is depressurized to generate a low-pressure vapor flow and a low-pressure liquid flow; At least a portion of the cooling load used to cool the feed stream originates from cooling provided through indirect heat exchange with the low-pressure liquid stream.

11. The method of claim 10, wherein the low-pressure liquid stream comprises more than 97% H2 by volume.

12. The method of claim 10, further comprising compressing the low-pressure steam stream to generate a compressed low-pressure steam stream; Heating the compressed low-pressure steam stream to generate a low-pressure circulating stream; and The low-pressure circulating stream is combined with the supercooled hydrogen-helium mixture before being separated to form the medium-pressure vapor stream and the medium-pressure liquid stream.

13. The method of claim 10, further comprising depressurizing the subcooled intermediate-pressure liquid flow to generate an intermediate-pressure vapor flow and an intermediate-pressure liquid flow; and The intermediate-pressure liquid flow is depressurized to generate the low-pressure vapor flow and the low-pressure liquid flow; At least a portion of the cooling load used to cool the feed stream originates from cooling provided through indirect heat exchange with the intermediate-pressure liquid stream.

14. The method of claim 13, further comprising compressing the intermediate pressure steam stream to generate a compressed intermediate pressure steam stream; Heating the compressed intermediate-pressure vapor stream to generate an intermediate-pressure circulating stream; and The intermediate-pressure circulating stream is combined with the supercooled hydrogen-helium mixture before being separated to form the intermediate-pressure vapor stream and the intermediate-pressure liquid stream.

15. The method of claim 10, further comprising catalyzing a reaction to form secondary hydrogen from the positive hydrogen in the feed stream prior to cooling to produce a supercooled medium-pressure flow.

16. A method for producing ammonia from a synthetic ammonia feed stream comprising hydrogen, nitrogen, and helium, the method comprising: The hydrogen and nitrogen in the ammonia synthesis feed stream are reacted to produce a crude ammonia stream. The crude ammonia stream is partially condensed and separated to produce a first ammonia product stream and an ammonia condenser column overhead stream. At least a portion of the ammonia condenser column overhead stream is separated to produce a second ammonia product stream and a first light component stream; The first light component stream is separated to produce a nitrogen-rich light component stream and a nitrogen-poor light component stream; The nitrogen-poor light component stream is separated to produce a hydrogen-rich light component stream and a helium-rich light component stream; as well as The hydrogen-rich light component stream is combined with the ammonia synthesis feed stream.

17. The method of claim 16, further comprising contacting a hydrogen feed stream containing helium, hydrogen and one or more impurities with a liquid nitrogen stream to produce a purified feed stream depleted of the one or more impurities and a waste liquid nitrogen stream enriched with the one or more impurities. The ammonia synthesis feed stream includes the purified feed stream.

18. The method of claim 16, wherein the first light component stream is separated by selectively permeating the nitrogen-poor light component stream through the membrane.

19. The method of claim 16, wherein the separation of the nitrogen-poor light component stream comprises contacting the nitrogen-poor light component stream or a stream derived from the nitrogen-poor light component stream with an adsorbent at a temperature below 30 K.

20. The method of claim 19, further comprising regenerating the adsorbent with a regeneration gas to generate waste regeneration gas; and The waste regenerated gas is combined with the synthetic ammonia feed stream.

21. A method, the method comprising: A purified feed stream containing hydrogen and helium is reacted with a precursor to produce a hydrogenation reactor effluent containing a hydrogen carrier. The effluent from the hydrogenation reactor is separated to produce a liquid stream enriched with the hydrogen carrier and an effluent from the top of the hydrogenation reactor column; Separate the effluent stream from the top of the hydrogenation reactor or the stream originating from the effluent stream from the top of the hydrogenation reactor to produce a hydrogen-rich light component stream and a helium-rich light component stream; as well as The hydrogen-rich light component stream is combined with the feed stream to the hydrogenation reactor.

22. The method of claim 21, further comprising contacting a hydrogen feed stream containing helium, hydrogen and one or more impurities with a liquid nitrogen stream to produce a purified feed stream depleted of the one or more impurities and a waste liquid nitrogen stream enriched with the one or more impurities; Prior to separating the nitrogen-poor light component stream to generate the hydrogen-rich light component stream and the helium-rich light component stream, the overhead effluent from the hydrogenation reactor is separated to generate the nitrogen-rich light component stream and the nitrogen-poor light component stream.

23. The method of claim 22, wherein the overhead stream from the hydrogenation reactor is separated by selectively permeating the nitrogen-poor light component stream through a membrane.

24. The method of claim 22, wherein the separation of the nitrogen-poor light component stream comprises contacting the nitrogen-poor light component stream or a stream derived from the nitrogen-poor light component stream with an adsorbent at a temperature below 30 K.

25. The method of claim 24, further comprising regenerating the adsorbent to generate waste regeneration gas; and The waste regenerated gas is combined with the purified feed stream.

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