System and method for cooling a fluid containing hydrogen or helium

Abstract

A system for cooling a feed stream containing hydrogen or helium with a mixed refrigerant includes a pre-cooling heat exchanger. A compression system has an inlet in fluid communication with the pre-cooling heat exchanger and receives a refrigerant vapor stream containing hydrogen and / or helium that is mixed with at least one other refrigerant such that the molecular weight of the mixture is greater than 6 kg / kgmol and increases its pressure. The compression system has an outlet in fluid communication with the pre-cooling heat exchanger. A first refrigerant separator receives fluid from the pre-cooling heat exchanger and has a liquid outlet and a vapor outlet in fluid communication with the pre-cooling heat exchanger. A refrigerant purifier has a purifier inlet in fluid communication with the vapor outlet of the first refrigerant separator and an outlet in fluid communication with the pre-cooling heat exchanger.

Description

Technical Field

[0001] Claims of Priority

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 342,338, filed May 16, 2022, the contents of which are incorporated herein by reference.

[0002]

[0002] The present disclosure generally relates to systems and methods for liquefying gases, and more particularly, to systems and methods for liquefying fluids containing hydrogen or helium.

Background Art

[0003]

[0003] Industrial gases such as natural gas or hydrogen are advantageously stored or transported in a liquid state because they occupy a much smaller volume (e.g., natural gas is 1 / 600 in the gaseous state and hydrogen is 1 / 848). The liquefied gas is usually evaporated at the site or in the system to return to the gaseous state for use.

[0004]

[0004] Gaseous hydrogen is converted to liquid hydrogen by cooling to below about 20 - 25K. Typical processes of cooling utilize a large amount of energy and can be very costly in terms of equipment expenses. This process involves a number of refrigeration cycles and may require multi-stage gas compression.

[0005]

[0005] Conventional hydrogen liquefaction systems generally use reciprocating compressors or screw compressors. Systems and / or processes that can use dynamic compressors for hydrogen liquefaction are desirable. Dynamic compressors are more reliable than reciprocating compressors and more efficient than screw compressors. Dynamic compressors include compressors that do not require a positive displacement type, such as centrifugal compressors, radial flow compressors, or axial flow compressors. In conventional liquefaction systems, dynamic compressors are not very suitable for low molecular weight gases (<6 kg / kgmol) such as hydrogen or helium.

[0006]

[0006] An example of a prior art hydrogen liquefaction system is presented in Beddome's U.S. Patent No. 3,992,167, which describes a process in which propane is added to hydrogen such that the compressed refrigerant cycle stream is 33% propane and 67% hydrogen. The additional component having a higher molecular weight than propane is desirable to allow more of the compression force to be used for hydrogen or helium, thereby improving the efficiency of the process, and to facilitate the separation of the additional component from hydrogen or helium. The process of Beddome's '167 patent also includes a single adsorption purification unit for the hydrogen stream to proceed to the coldest part of the process. This results in uncondensed hydrocarbons being released from the process when the adsorbent is regenerated. A process with near-zero hydrocarbon emissions is desirable and can be particularly important in response to environmental regulations.

[0007]

[0007] Grenier's U.S. Patent No. 5,579,655 describes a prior art process in which small amounts of saturated C 2 , C 3 , optionally C 4 , and C 5 hydrocarbons are mixed with hydrogen to form a mixed refrigerant. This process includes a separate hydrogen feed stream that is liquefied and does not mix with the mixed refrigerant stream, so a double cryogenic purifier at 75 - 80K is required. Since ethane is included in the mixed refrigerant, the purification of hydrogen from the small amount of mixed refrigerant components becomes more complex and a liquid propane scrubbing tower is required to perform the separation, leading to the need for a continuous hydrocarbon replenishment to compensate for hydrocarbon losses to the environment. The liquid propane scrubbing tower also adds cost and complexity to the process.

[0008]

[0008] U.S. Patent No. 10,928,127 to Cardella et al. describes a process using a mixed refrigerant for hydrogen liquefaction. The above-mentioned mixed refrigerant includes nitrogen, neon, argon, and hydrocarbons, but does not include hydrogen or helium. The mixed refrigerant of the invention described herein needs to include hydrogen or helium. Further, the process described in U.S. Patent No. 10,928,127 also uses an essentially pure hydrogen stream that requires a positive displacement compressor as a separate refrigerant in addition to the mixed refrigerant. The process described in U.S. Patent No. 10,928,127 does not achieve precooling the hydrogen feed to less than 85K. This increases the refrigeration load on the hydrogen refrigerant compared to a standard process using liquid nitrogen for precooling or the invention described herein.

[0009]

[0009] U.S. Patent No. 3,490,245 to Muenger describes a heat exchanger that removes trace impurities including carbon dioxide, hydrogen sulfide, carbon disulfide, and carbonyl sulfide from a purified stream by freezing them out of an ammonia synthesis feed. This type of heat exchanger has been proven to be used in place of an adsorption system to remove impurities that would otherwise freeze in the cold box heat exchanger. A freezing device is defined as a device that removes one or more impurities from a mixed stream by selectively freezing one or more specific components. The device described in U.S. Patent No. 3,490,245 is one example of a freezing device.

SUMMARY OF THE INVENTION

MEANS FOR SOLVING THE PROBLEM

[0010] The methods, apparatuses, and systems described and claimed below include multiple aspects of the subject matter that may be embodied separately or together. These aspects may be employed alone or in combination with other aspects of the subject matter described herein, and the descriptions of these aspects together are not intended to exclude claims in which these aspects are used separately or in a different combination than those described or claimed in the claims appended hereto.

[0011]

[0011] In one aspect, a system for cooling a supply stream that includes hydrogen or helium with a mixed refrigerant includes a pre-cooling heat exchanger having a supply stream cooling passage, a first refrigerant cooling passage, a second refrigerant cooling passage, and a refrigerant heating passage. A compression system has an inlet in fluid communication with the refrigerant heating passage and is configured to receive and increase the pressure of a refrigerant vapor stream of hydrogen and / or helium that is mixed with at least one other refrigerant such that the molecular weight of the mixture is greater than 6 kg / kgmol. The compression system has an outlet in fluid communication with the first refrigerant cooling passage. A first refrigerant separation device is configured to receive fluid from the first refrigerant cooling passage in the pre-cooling heat exchanger. A first refrigeration separation device has a liquid outlet and a vapor outlet in fluid communication with the refrigerant heating passage. A refrigerant purifier has a purifier inlet in fluid communication with the vapor outlet of the first refrigerant separation device and an outlet in fluid communication with the second refrigerant cooling passage. The second refrigerant cooling passage has an outlet in fluid communication with the refrigerant heating passage.

[0012] In another aspect, a method for liquefying a feed stream containing hydrogen or helium includes mixing a hydrogen or helium refrigerant with at least one additional refrigerant component having a molecular weight higher than that of hydrogen or helium to form a mixed refrigerant having a molecular weight of at least 6 kg / kgmol; compressing the mixed refrigerant using a dynamic compressor; separating at least one additional refrigerant component from the hydrogen or helium refrigerant at a temperature of 75 K or warmer to obtain the remaining hydrogen or helium refrigerant; and cooling the hydrogen or helium feed stream using the remaining hydrogen or helium refrigerant to produce liquid hydrogen or helium product from the feed stream.

[0013]

[0013] In yet another aspect, a system for cooling a cryogenic fluid supply stream that includes hydrogen or helium with a mixed refrigerant includes a precooling supply stream cooling passage, a low-pressure refrigerant heating passage, an intermediate-pressure refrigerant heating passage, a first refrigerant cooling passage, and a precooling heat exchanger having a second refrigerant cooling passage. The mixed gas compressor is configured to receive a mixed refrigerant vapor stream from the low-pressure refrigerant heating passage. The mixed gas aftercooler is in fluid communication with the mixed gas compressor. The mixing device has a first inlet, a second inlet, and a mixing device vapor outlet that are in fluid communication with the mixed gas aftercooler. The second inlet is configured to receive a mixed refrigerant vapor stream from the intermediate-pressure refrigerant heating passage. The first interstage compressor is in fluid communication with the mixing device vapor outlet. The first interstage aftercooler is in fluid communication with the first interstage compressor. The high-pressure accumulator is in fluid communication with the first interstage aftercooler and has a high-pressure accumulator vapor outlet and a high-pressure accumulator liquid outlet. The high-pressure accumulator vapor outlet is in fluid communication with the first refrigerant cooling passage, and the high-pressure accumulator liquid outlet is in fluid communication with the intermediate-pressure refrigerant heating passage. The first refrigerant separation device is in fluid communication with the first refrigerant cooling passage and has a first refrigerant separation device liquid outlet that is in fluid communication with the low-pressure refrigerant heating passage and a first refrigerant separation device vapor outlet that is in fluid communication with the second refrigerant cooling passage. The second refrigerant separation device is in fluid communication with the second refrigerant cooling passage and also has a second refrigerant separation device liquid outlet that is in fluid communication with the low-pressure refrigerant heating passage and a second refrigerant separation device vapor outlet. The refrigerant purifier has a purifier inlet and a purifier outlet that are in fluid communication with the second refrigerant separation device vapor outlet, and the purifier outlet is in fluid communication with the low-pressure refrigerant heating passage and the intermediate-pressure refrigerant heating passage.

Brief Description of the Drawings

[0014]

Figure 1

[0014] FIG. 8 is a process flow diagram showing a first embodiment of a precooling portion of an embodiment of the system of the present disclosure.

Figure 2

[0015] FIG. 12 is a process flow diagram showing an embodiment of a liquefaction portion of an embodiment of the system of the present disclosure.

Figure 3

[0016] It is a process flow diagram showing a second embodiment of a precooling portion of an embodiment of the system of the present disclosure.

Figure 4

[0017] It is a process flow diagram showing a third embodiment of a precooling portion of an embodiment of the system of the present disclosure.

Figure 5

[0018] It is a process flow diagram showing a fourth embodiment of a precooling portion of an embodiment of the system of the present disclosure.

Mode for Carrying Out the Invention

[0015]

[0019] It should be noted that in this specification, a line, conduit, pipe, passage, and similar structures, and the corresponding flows may be referred to with the same element numbers described in the figures.

[0016]

[0020] Also, as used in this specification, as is known in the art, a heat exchanger is a device or a region within a device where indirect heat exchange occurs between two or more flows at different temperatures or between a flow and the environment. In addition, all heat exchanges referred to in this specification may be incorporated into one or more heat exchanger devices, or each may be an individual heat exchanger device. As used in this specification, terms such as "communicate" and "communicating" refer to overall fluid communication unless otherwise specified. And two fluids in communication can exchange heat when mixed, but such an exchange will not be equal to heat exchange in a heat exchanger. That said, such an exchange may also occur within a heat exchanger.

[0017]

[0021] As used in this specification, terms such as "high," "intermediate," "warm," and "cold" are relative to a corresponding flow as is customary in the art.

[0018]

[0022] Any tower or building referred to in the following description can be, by way of non-limiting example only, a spray tower, a packed tower, a plate column, and / or any combination thereof.

[0019]

[0023] In this specification, reference numerals introduced in connection with the drawings may be repeated in one or more subsequent drawings without additional explanation in the specification that provides context for other features, for common elements or components.

[0020]

[0024] In the claims, letters (e.g., a, b, and c) are used to identify the claimed steps. These letters are used to aid in referring to method steps and are not intended to indicate the order in which the claimed steps are to be performed, unless and only to the extent that the order of performance is specifically indicated in the claims.

[0021]

[0025] The embodiments of the present disclosure described below provide processes and apparatus for the liquefaction of hydrogen or helium of a type that uses a refrigeration cycle in which the cycle fluid mainly comprises hydrogen or helium and a closed refrigeration cycle of an optional auxiliary refrigerant. The primary refrigeration cycle fluid is a mixture containing hydrogen or helium and at least one additional component having a higher molecular weight and a higher boiling point, and this additional component is compressed outside the cold box and used to provide cooling to the hydrogen or helium feed stream within the cold box. One or more additional components are removed from the refrigerant stream rich in hydrogen or helium within the cold box by a series of preferential and partial condensation steps, as well as adsorption and / or freezing and / or distillation below ambient temperature and warmer than about 75K. The removed components are flowed to the low pressure section, reheated, and recycled to return to a point in the compression train, providing cooling to the cold box. In at least one interstage compression cylinder, a processing step of controlled direct heat and mass transfer between hydrogen or helium and one or more additional components is included. This interstage compression cylinder operates as a direct contact mixing vessel to effect simultaneous heat and mass transfer, which ensures, in all scenarios, the evaporation of the high molecular weight component and the control of the mixed refrigerant stream composition, molecular weight, and thermal properties. The remaining ultra-cold purified hydrogen or helium is used as the primary refrigerant at a temperature of less than about 75 to 80K.

[0022]

[0026] Increasing the molecular weight of the compressed hydrogen or helium-containing stream by mixing with other components to be removed later allows the use of a dynamic compressor instead of a less reliable reciprocating compressor during the compression of the mixed refrigerant.

[0023]

[0027] In addition, in the embodiments described below, using components with a higher molecular weight than in the prior art improves the performance of the compressor while maintaining a relatively high hydrogen concentration in the mixture. The use of fluorinated hydrocarbons increases the molecular weight of the added components, which reduces the amount required to increase the molecular weight of the mixture, and as a result, the concentration of hydrogen or helium in the mixture can be increased.

[0024]

[0028] The embodiments disclosed below reduce the power required for the pre-cooling cycle of the auxiliary refrigerant by leveraging the auxiliary refrigeration function provided by higher molecular weight components. This auxiliary refrigeration function mainly occurs above about 190K. These improvements enhance the overall efficiency of the pre-cooling process. The excess auxiliary refrigeration function provided may exceed the requirements of the hydrogen / auxiliary refrigerant pre-cooling system, and this excess function can provide refrigeration to other processes or systems.

[0025]

[0029] The embodiments disclosed below also use a refrigerant mixture that does not contain hydrocarbons boiling at temperatures lower than about 190K. Eliminating ethane and ethylene from the mixtures presented in the prior art greatly simplifies and improves the separation of hydrocarbons from the hydrogen or helium stream before it is supplied to the cold final process. The figure descriptions refer to the case where hydrogen is the feed stream and the substance to be liquefied. When helium is used, there is no ortho-para conversion catalyst and the final temperature is lower, but the descriptions generally apply.

[0026]

[0030] In one embodiment, as shown in FIG. 1, a high-pressure hydrogen supply 101 at approximately 14 to 26 bar (1400 kPa to 2600 kPa) and at approximately ambient temperature is cooled in a precooling heat exchanger 1 to approximately 77 to 80 K and exits as a precooled hydrogen supply 102. As is known in the art, the precooling heat exchanger 1 is positioned inside a thermally insulated cold box 7. The precooling heat exchanger 1 can be filled with an ortho-para conversion catalyst 2 in a hydrogen cooling path to promote the conversion of a portion of the ortho-hydrogen in the high-pressure hydrogen supply 101 to para-hydrogen. The precooled hydrogen supply 102 is sent to an adsorption-type cryogenic purifier (51 shown in FIG. 2) similar to the second refrigerant purifier 23, and a hydrogen liquefaction process in which most of the hydrogen is liquefied is well known in the art (an example is shown in FIG. 2). A small portion of the precooled hydrogen supply is returned to the precooling heat exchanger 1 as a cold hydrogen recycle stream 103.

[0027]

[0031] The cold hydrogen recycle stream 103 is warmed in the precooling heat exchanger 1 to provide cooling for the high-pressure hydrogen supply 101. The cold hydrogen recycle is at a lower pressure than the high-pressure hydrogen supply 101. This stream can optionally be passed through a para-ortho conversion catalyst 3 to utilize the extra cooling capacity available from the conversion. The cold hydrogen recycle stream 103 exits the precooling heat exchanger 1 as a warm hydrogen recycle stream 104, which can be compressed and returned to the process as part of the high-pressure hydrogen supply 101.

[0028]

[0032] Often, an optional high-pressure auxiliary refrigerant 111, such as nitrogen, is cooled in the precooling heat exchanger 1 to form a cold high-pressure auxiliary refrigerant stream 112, which is expanded in the auxiliary refrigerant expander 4 to form a cold auxiliary refrigerant stream 113. The cold auxiliary refrigerant stream 113 provides cooling to the precooling heat exchanger 1 and exits as a warm low-pressure auxiliary refrigerant stream 114, which is compressed in the auxiliary refrigerant compressor 5 to form a hot compressed auxiliary refrigerant stream 115, which is cooled in the auxiliary refrigerant compressor aftercooler 6 to form the high-pressure auxiliary refrigerant supply 111. The auxiliary refrigerant compressor 5 and the aftercooler 6 can consist of two or more stages depending on the desired pressure rise. Similarly, the auxiliary refrigerant expander 4 can also consist of two or more stages. Alternatively, the cycle can be enhanced to include a more efficient arrangement, such as that shown in Figure 3.

[0029]

[0033] A low-pressure gas mixture 121 composed of hydrogen and / or helium and at least one other substance having a higher molecular weight and a boiling point exceeding 80 K is compressed in a first mixed gas compressor 11 and cooled in a first compressor aftercooler 12 to form a first intermediate pressure mixture 122, which can be sent to a mixing vessel 13. The first mixed gas compressor 11 can be a single-stage compressor, a compressor having two or more stages, or one or more of the lowest pressure stages of a multi-stage compressor. The mixing vessel 13 is designed to operate with or without a liquid level and includes a sparger and / or a heating coil, packing, or other devices for enhancing direct contact and heat and mass transfer between the inlet streams. Examples of these other substances include hydrocarbons, halogenated hydrocarbons, perfluorocarbons, neon, and other refrigerants. A second mixture 123 exits the mixing vessel 13, is compressed in a second mixed gas compressor 14, and cooled in a second compressor aftercooler 15 to form a second intermediate pressure mixture 124, which is supplied to a first phase separator or inter-stage separator 16 designed to remove any small amount of liquid that may form. The second mixed gas compressor 14 can be a single-stage compressor, a compressor having two or more stages, or one or more of the stages of a multi-stage compressor operating at a higher pressure than the first mixed gas compressor. The controlled action of the heat input to the mixing vessel 13 allows the second mixture 123 to operate at or near its saturation point or dew point conditions, maximizing the amount of the higher molecular weight component in the mixture. This increases the molecular weight of the second mixture and improves its ability to be compressed. A third mixture 125 exits the inter-stage separator 16, is compressed in a third mixed gas compressor 17, and cooled in a third compressor aftercooler 18 to form a high-pressure mixture 126, which is supplied to a second phase separator or high-pressure accumulator 19. The third compressor can be a single-stage compressor, a compressor having two or more stages, or one or more of the stages of a multi-stage compressor operating at a higher pressure than the second compressor. As shown in FIG. 1 and in all subsequent embodiments, the first mixed gas compressor 11, the second mixed gas compressor 14, and the third mixed gas compressor 17 are positioned outside the cold box 7.

[0030]

[0034] From the bottom of the inter-stage separation device 16, the first liquid 160 can emerge and be discharged through the first phase separator valve 41 to form a low-pressure first liquid 161. From the bottom of the high-pressure accumulator 19, a second liquid 162 mainly containing high-molecular-weight components in the original mixture can emerge and be discharged through the second phase separator valve 42 to form a low-pressure second liquid 163, which can be mixed with the low-pressure first liquid 161 to form a low-pressure mixed liquid 164.

[0031]

[0035] The low-pressure mixed liquid 164 can be distributed into four different flows: the mixing vessel recirculation flow 170, the mixing vessel refrigeration supply 166, the low-pressure gas mixture vessel refrigeration supply 167, and the low-pressure gas mixture vessel recirculation flow 172. The mixing vessel recirculation flow 170 is expanded through the mixing vessel valve 43 to form a low-pressure mixing vessel recirculation flow 171, which is returned to the mixing vessel 13. The mixing vessel refrigeration supply 166 is expanded through a mixing vessel refrigeration expansion device 45 such as a valve to form a cooled mixing vessel refrigerant 169, which provides cooling to the pre-cooling heat exchanger 1 and returns to the mixing vessel 13. A part 174 of the cooled mixing vessel refrigerant can be sent through the pre-cooling heat exchanger 1 as a separate flow, and as a result, it exits the pre-cooling heat exchanger 1 as a two-phase flow. This can reduce the temperature difference in the heat exchanger and improve efficiency. The low-pressure gas mixture vessel refrigeration supply 167 is expanded through a low-pressure mixture vessel refrigeration expansion device 46 such as a valve to form a cooled low-pressure gas mixture vessel refrigerant 168, which provides cooling to the pre-cooling heat exchanger 1 and returns to the low-pressure gas mixture vessel 24. The low-pressure gas mixture vessel recirculation flow 172 is expanded through the low-pressure gas mixture vessel valve 44 to form a decompressed gas mixture vessel recirculation flow 173, which is returned to the low-pressure gas mixture vessel 24. The liquid 175 accumulated from the mixing vessel 13 is pressurized using the mixing vessel pump 49 to form a pressurized accumulated liquid 176, which can be mixed with the first liquid 160 or the second liquid 162. The pump 49 and the mixing vessel 13 enable the molecular weight of the compressor supply flow to be controlled and maintained at a relatively high level. Alternatively, the accumulated liquid 175 can be mixed with the low-pressure gas mixture vessel supply 143 and supplied to the low-pressure gas mixture vessel 24 (not shown).

[0032]

[0036] From the top of the high-pressure accumulator 19, the second-phase separator vapor 127 exits, is cooled in the pre-cooling heat exchanger 1 to form the first cooled mixed refrigerant 128, which is supplied to the first mixed refrigerant separator 20. From the top of the first mixed refrigerant separator 20, the first mixed refrigerant vapor 129 exits, returns to the pre-cooling heat exchanger 1, where it is further cooled to form the second cooled mixed refrigerant stream 130, which is supplied to the second mixed refrigerant separator 21. From the top of the second mixed refrigerant separator 21, the second mixed refrigerant vapor 131 exits and is purified in a mixed refrigerant purifier 22 that essentially removes all mixture components having a boiling point above 80K. The mixed refrigerant purifier 22 can be an adsorption system that preferentially removes components of the mixture having a boiling point above 80K. The adsorption system generally consists of two or more adsorption beds such that while one or more beds are in operation, another one or more beds can be regenerated. Also, a freezing device, a distillation column, or other purification methods can be used as the refrigerant purifier. The freezing device will require similar regeneration. A mixed refrigerant purifier regeneration supply 191 is used to sweep away the impurities captured by the mixed refrigerant purifier 22 and regenerate it for a new supply step. The purifier regeneration supply generally consists of nitrogen, hydrogen, helium, or a mixture thereof. The regeneration is generally carried out at a lower pressure and higher temperature than the typical operating pressure and temperature of the purifier. When there are at least two mixed refrigerant purifiers, in the first purifier, it becomes possible to selectively remove trace amounts of heavier refrigerant components without removing lighter impurities introduced into the supply such as nitrogen or argon. The impurity-containing regeneration stream 192 can be recycled to the inlet of the first mixed gas compressor or the low-pressure gas mixing vessel 24. This enables the system to recover trace amounts of other substances in the mixed refrigerant removed in the refrigerant purifier 22. When hydrocarbons are used as the other substance, this ensures an essentially complete recovery of hydrocarbons and an essentially zero hydrocarbon emission, which is different from prior art processes.

[0033]

[0037] The purified hydrogen / helium stream 132 exits the mixed refrigerant purifier 22, returns to the pre-cooling heat exchanger 1 where it is further cooled, and exits as the cooled refrigerant 133, which is then further purified in the second refrigerant purifier 23. While the mixed refrigerant purifier 22 is designed to remove substances of higher molecular weight having boiling points above 80K, the second refrigerant purifier is similar to the mixed refrigerant purifier except that it is designed to remove lighter impurities including nitrogen and argon. The cryogenic refrigerant 134 leaves the second refrigerant purifier 23 and is supplied to the hydrogen liquefaction process. Similar to the mixed refrigerant purifier 22, a second refrigerant purifier regeneration supply 193 is used to regenerate the second refrigerant purifier 23. All or part of the second impurity-containing regeneration stream 194 can be recycled to a raw hydrogen purifier (not shown), or can be exhausted if nitrogen, argon, and other light impurities would increase to an unacceptable high concentration if not removed at all. Alternatively, part of the regeneration stream can be recycled to the compressor inlet depending on its pressure. The raw hydrogen purifier is a device placed upstream of the high-pressure hydrogen supply 101 and can be, for example, a pressure swing adsorption system that separates hydrogen from other components in a mixture produced by a hydrogen regeneration system such as a reformer or an electrolyzer. In one alternative form, the two refrigerant purifiers can be combined into a single unit. In that case, the regeneration stream can be recycled to the raw hydrogen purifier, or part of the regeneration stream can be recycled to the compressor inlet depending on its pressure.

[0034]

[0038] From the bottom of the first mixed refrigerant separator 20, the first mixed refrigerant liquid 181 exits and is expanded in a first mixed refrigerant liquid expansion device 47, such as a valve, to cool and reduce the pressure of the flow, forming a cooled low-pressure first mixed refrigerant liquid stream 182. From the bottom of the second mixed refrigerant separator 21, the second mixed refrigerant liquid 184 exits and is expanded in a second mixed refrigerant liquid expansion device 48, such as a valve, to cool and reduce the pressure of the flow, forming a cooled low-pressure second mixed refrigerant liquid stream 185. The cooled low-pressure first mixed refrigerant liquid stream 182 and the cooled low-pressure second mixed refrigerant liquid stream 185 combine to form a low-pressure mixed refrigerant recycle stream 183, which enters the pre-cooling heat exchanger 1 to provide cooling.

[0035]

[0039] The low-pressure refrigerant 141 is recycled from the hydrogen liquefaction process and enters the precooling heat exchanger 1 to provide cooling. The low-pressure refrigerant 141 mixes with the cooled low-pressure gas mixture vessel refrigerant 168 and the low-pressure mixed refrigerant recycle stream 183 within the precooling heat exchanger 1 and exits as the heated mixed refrigerant 142, which combines with the depressurized gas mixture vessel recycle stream 173 to produce the low-pressure gas mixture vessel supply 143, which enters the low-pressure gas mixture vessel 24.

[0036]

[0040] The intermediate-pressure refrigerant 151 exits the hydrogen liquefaction process and enters the precooling heat exchanger 1 to provide cooling. The intermediate-pressure refrigerant 151 mixes with the cooled mixed vessel refrigerant 169 within the precooling heat exchanger 1 and exits as the mixed vessel recycle supply 152, which enters the mixed vessel 13.

[0037]

[0041] FIG. 2 shows an exemplary cold final process for producing liquid hydrogen product. There are numerous variations that may be appropriate for the techniques of this disclosure relative to this configuration known in the art. The example shown in FIG. 2 is merely one of many possible options. The cold final configuration selected has no significant impact on the techniques of this disclosure or its use.

[0038]

[0042] The precooled hydrogen supply 102 from FIG. 1 enters a hydrogen supply purifier 51 similar to the second refrigerant purifier of FIG. 1. The hydrogen supply purifier removes any impurities in the hydrogen supply before the stream is further cooled. These impurities generally consist primarily of nitrogen and argon, as well as other trace components that may freeze in heat exchangers at lower temperatures. The purified hydrogen supply 201 exits the hydrogen supply purifier 51 and enters the first cold heat exchanger 53, where it is cooled and a portion of the ortho-hydrogen is converted to para-hydrogen by a conversion catalyst placed in the first cold heat exchanger catalyst passage 52 to produce the second purified hydrogen supply 202.

[0039]

[0043] The second purified hydrogen supply 202 exits the first cold heat exchanger 53 and enters the second cold heat exchanger 55, where a part of the ortho-hydrogen is converted to para-hydrogen by a conversion catalyst placed in the catalyst passage 54 of the second cold heat exchanger, generating the third purified hydrogen supply 203. The third purified hydrogen supply 203 exits the second cold heat exchanger 55 and enters the third cold heat exchanger 57, where a part of the ortho-hydrogen is converted to para-hydrogen by a conversion catalyst placed in the catalyst passage 56 of the third cold heat exchanger, generating the fourth purified hydrogen supply 204. The fourth purified hydrogen supply 204 exits the third cold heat exchanger 57 and enters the fourth cold heat exchanger 59, where a part of the ortho-hydrogen is converted to para-hydrogen by a conversion catalyst placed in the catalyst passage 58 of the fourth cold heat exchanger, generating the fifth purified hydrogen supply 205. The cold heat exchangers can be combined into one, two, or three heat exchangers with side supply ports and outlets as needed. In most cases, these heat exchangers will be combined to reduce capital costs, piping, connections, and the volume of the cold box. The combination of heat exchangers selected does not affect the technology of the present invention or its use.

[0040]

[0044] The fifth purified hydrogen supply 205 is expanded through an expansion device such as the hydrogen product expansion valve 60 to form a two-phase hydrogen supply 206, which is separated in the hydrogen product separator 61. Liquid hydrogen product 207 is removed from the bottom of the separator. Cold hydrogen vapor 208 is removed from the top of the separator and supplied to the fourth cold heat exchanger 59, the third cold heat exchanger 57, the second cold heat exchanger 55, and the first cold heat exchanger 53, where it is heated to provide cooling for the hydrogen supply. After exiting the fourth heat exchanger 59, the third heat exchanger 57, and the second heat exchanger 55, the cold hydrogen vapor 208 forms the first heated hydrogen vapor stream 209, the second heated hydrogen vapor stream 210, and the third heated hydrogen vapor stream 211, respectively, and exits the heat exchanger as the cold hydrogen recirculation stream 103 shown in FIGS. 1 and 2.

[0041]

[0045] The low-temperature refrigerant 134 leaves the second refrigerant purifier 23 shown in FIG. 1 and is supplied to the first cold heat exchanger 53 of FIG. 2, exiting as the first hydrogen refrigerant 221, which is split between the first expander supply 222 and the second cold heat exchanger refrigerant supply 223. The first expander supply 222 is expanded in the first hydrogen expander 62 to produce the first hydrogen expander product 224, which is used to effect cooling in the second cold heat exchanger 55, exiting as the heated first hydrogen expander product 225 and then exiting as the intermediate-pressure refrigerant 151 shown in FIGS. 1 and 2 after the first cold heat exchanger 53. The second cold heat exchanger refrigerant supply 223 is supplied to the second cold heat exchanger 55, exiting as the second hydrogen refrigerant 226, which is split between the second expander supply 227 and the third cold heat exchanger refrigerant supply 231. The second expander supply 227 is expanded in the second hydrogen expander 63 to produce the second hydrogen expander product 228, which is used to effect cooling in the third cold heat exchanger 57.

[0042]

[0046] The third cold heat exchanger refrigerant supply 231 is supplied to the third cold heat exchanger 57, exiting as the third hydrogen refrigerant 232, which is supplied to the hydrogen refrigerant expansion valve 64 to form the two-phase hydrogen refrigerant 233, which is separated in the refrigerant separator 65. Liquid refrigerant 237 is removed from the bottom of the separator, effecting cooling in the fourth cold heat exchanger 59, where it is at least partially evaporated and returned to the refrigerant separator as the second two-phase refrigerant 238. Cold hydrogen refrigerant vapor 234 is removed from the top of the refrigerant separator 65, mixed with the second hydrogen expander product 228 to form the cold refrigerant supply 229, which is supplied to the third cold heat exchanger 57, exiting as the second cold refrigerant supply 235, supplied to the second cold heat exchanger 55, exiting as the third cold refrigerant supply 236, supplied to the first cold heat exchanger 53, where it is heated to effect cooling for hydrogen supply. The cold refrigerant supply 229 exits the cold heat exchanger as the low-pressure refrigerant 141 shown in FIGS. 1 and 2. The heat exchangers 53, 55, 57, and 59 of FIG. 2 may be positioned within the cold box 7 of FIG. 1 or within one or more cold boxes of their own.

[0043]

[0047] Alternative forms of the process shown in FIG. 2 include processes in which the expander operates in series rather than in parallel, or processes in which the heat exchangers are combined in any of a number of possible configurations. When helium is used as the refrigerant and the process is used to liquefy hydrogen, it is not essential to produce liquid helium, and since there is no liquid refrigerant 237, the refrigerant separator 65 is also not essential. These changes do not affect the practice and advantages of the techniques described herein.

[0044]

[0048] FIG. 3 shows another exemplary warm final process with an improved auxiliary refrigerant cooling system. The auxiliary refrigerant can be nitrogen or other refrigerant having suitable refrigeration characteristics for the desired cycle. All numbers represent essentially the same flows or equipment as shown and previously described in FIG. 1. This alternative includes an improved auxiliary refrigerant refrigeration loop, where the precooled hydrogen feed 102 is mixed with the cooled refrigerant 133 and supplied to a single hydrogen purifier 33 to produce a combined precooled hydrogen stream 135. Other processes use an improved auxiliary refrigerant refrigeration loop or involve mixing of cold streams, while others are different.

[0045]

[0049] Combining the precooled hydrogen supply 102 and the purified hydrogen stream 132 to form the combined purifier feed 135 is advantageous in that only one cryogenic purifier is required for the two streams and the combined purifier product 136 is produced. The disadvantage is that both streams must be at the same pressure and the refrigerant and supply must be of the same substance. For example, if a helium refrigerant is used to liquefy hydrogen, the streams cannot be combined. The benefit of reducing capital costs by eliminating the second purifier and subsequent cold box reduction to determine if it is beneficial to mix the streams may be compared to the cost of reduced operating flexibility. In this case, a portion of the combined purifier product 136 is split to form the purified hydrogen supply 201 as shown in FIG. 2, while the remainder becomes the cryogenic refrigerant 134 as shown in FIG. 2.

[0046]

[0050] The improved auxiliary refrigerant refrigeration loop requires a cooled high-pressure auxiliary refrigerant stream 211, which is supplied to the pre-cooling heat exchanger 1. From the cooled high-pressure auxiliary refrigerant stream 211, a first auxiliary refrigerant portion 212 is taken out and expanded in the first auxiliary refrigerant expander 4 to form a first auxiliary refrigerant 213, which is returned to the pre-cooling heat exchanger 1, where it provides refrigeration. From the cooled high-pressure auxiliary refrigerant stream 211, at a temperature lower than the first portion 212, a second auxiliary refrigerant portion 214 is taken out and expanded in the second auxiliary refrigerant expander 5 to form a second auxiliary refrigerant 215, which is returned to the pre-cooling heat exchanger 1, where it provides refrigeration. The remaining auxiliary refrigerant 217 of the cooled high-pressure auxiliary refrigerant stream 211 exits the pre-cooling heat exchanger 1 at the lowest temperature and is expanded in the auxiliary refrigerant expansion valve 6 to form a cold auxiliary refrigerant 218, which is returned to the pre-cooling heat exchanger 1, where it provides refrigeration. The cold auxiliary refrigerant 218 is heated in the pre-cooling heat exchanger 1 to generate a heated low-pressure auxiliary refrigerant recirculation 219, which is compressed in the first auxiliary refrigerant compressor 7 to form a compressed first auxiliary refrigerant 220 and is cooled in the first auxiliary refrigerant compressor aftercooler 8 to generate a first intermediate-pressure auxiliary refrigerant recirculation 221. The first auxiliary refrigerant 213 and the second auxiliary refrigerant 215 are combined and heated in the pre-cooling heat exchanger 1 to generate a heated intermediate-pressure auxiliary refrigerant recirculation 216, which is combined with the first intermediate-pressure auxiliary refrigerant recirculation 221 to generate an intermediate-pressure auxiliary refrigerant 222. The intermediate-pressure auxiliary refrigerant 222 is compressed in the second auxiliary refrigerant compressor 9 to form a compressed intermediate-pressure auxiliary refrigerant 223 and is cooled in the second auxiliary refrigerant compressor aftercooler 10 to generate a cooled high-pressure auxiliary refrigerant stream 211. The first auxiliary refrigerant compressor and / or the second auxiliary refrigerant compressor can be one or more stages of a single-stage compressor, a compressor with two or more stages, or a multi-stage compressor such that the second auxiliary refrigerant compressor operates at a higher pressure than the first auxiliary refrigerant compressor.

[0047]

[0051] In one alternative form, the cooled portion of the high-pressure auxiliary refrigerant stream 211, the first portion 212, and the pressurized first auxiliary refrigerant portion 251 are withdrawn for use as refrigerant to an external process 31. The auxiliary refrigerant then returns to the process as the auxiliary refrigerant return stream 252. The external process 31 can be any process that can take advantage of the additional refrigeration between the temperature of the first auxiliary refrigerant portion 212 and the ambient temperature. Another alternative is that a portion of the first auxiliary refrigerant 213 can be withdrawn. This has the advantage of being at a lower temperature and not requiring an additional expansion device in the external process 31, as well as having a lower pressure and less driving force moving through the external process 31.

[0048]

[0052] In the process of FIG. 4, the warm mixed vessel refrigeration supply 165 is supplied to the precooling heat exchanger 1 and then expanded in the mixed vessel refrigeration expansion device 45. This allows the cooled mixed vessel refrigerant 169 to be colder than the temperature that would otherwise be possible, providing additional cooling to the process. Another variation shown in FIG. 4 is that the first mixed refrigerant liquid 181 is split and expanded in a first mixed refrigerant liquid expansion device 47B or a second mixed refrigerant liquid expansion device 47A, such as a valve, to cool and depressurize the stream to form a cooled low-pressure first mixed refrigerant liquid stream 182, or a second low-pressure mixed refrigerant recirculation stream 183A having a pressure higher than the cooled low-pressure first mixed refrigerant liquid stream 182. The cooled low-pressure first mixed refrigerant liquid stream 182 is combined with the cooled low-pressure second mixed refrigerant liquid stream 185 to form a cold mixed refrigerant recirculation stream 183B, which is mixed with the low-pressure refrigerant 141 in the precooling heat exchanger 1 to provide refrigeration to the process.

[0049]

[0053] Other potential configurations that enable the practice of the disclosed technology will be apparent to those skilled in the art.

[0054]

Example

[0050]

[0055] The following example shows, with reference to FIG. 5, one possible way to implement the present invention. The process produces 15 tons per day (625 kg / h) of liquid hydrogen product. The conditions and composition for the selected stream are shown in Table 1.

[0051]

[0056] The mixed refrigerant selected for this example is a mixture of hydrogen, propane, and isopentane. The molecular weight of the low-pressure gas mixture 121 is about 28 kg / kgmol, and the molecular weight of the second mixture 123 is about 11 kg / kgmol. These are high enough to use a dynamic compressor, which has higher reliability than a typical positive-displacement compressor used for hydrogen having a molecular weight of about 2 kg / kgmol. Other hydrocarbons, including halogenated and partially halogenated hydrocarbons, or other refrigerants can be used. Other compositions or ratios can also be used. Due to the conditions and refrigerant composition in the example, there is no flow in the streams 160, 167, 170, 172, or 175 shown in FIG. 4, so those streams are not shown in FIG. 5.

[0052]

[0057] The high-pressure hydrogen supply 101 is 373.5 kgmol / h. The warm hydrogen recycle stream 104 flow is 35.3 kgmol / h. This means that 338.2 kgmol / h of hydrogen is liquefied in the process. The liquid product flow is 15 metric tons per day, or 310.0 kgmol / h. The estimated losses are 7 - 10% or about 8.5% from the process to the trucks going outside the plant gate. Most of these losses can be recovered by appropriate equipment not described here and recycled back to the supply.

[0053]

[0058] The refrigeration required to produce the liquid product is provided by a low-pressure gas mixture 121 containing 51.4% hydrogen, 29.4% propane, and 19.2% isopentane, which is compressed in the first mixed gas compressor 11 from 1.2 bar (120 kPa) to 4.0 bar (400 kPa). This stream is mixed with the mixed vessel recirculation feed 152 in the mixing vessel 13 to form a second mixture 123, which is compressed to 34.1 bar (3410 kPa) and separated in the second phase separator 19. The second liquid 162 leaving the second phase separator 19 contains most of the isopentane, some propane, and a small amount of dissolved hydrogen. This stream is cooled to 199.8 K in the pre-cooling heat exchanger 1 and recycled to the mixing vessel 13.

[0054]

[0059] From the top of the second phase separator 19, a second phase separator vapor 127 exits and is cooled to 155.3 K in the pre-cooling heat exchanger 1 to form a first cooled mixed refrigerant 128, which is supplied to the first mixed refrigerant separator 20. From the bottom of the first mixed refrigerant separator 20, a first mixed refrigerant liquid 181 containing almost all of the remaining isopentane and most of the propane exits and is split into streams 183A and 182. Stream 183A is expanded to 4.1 bar (410 kPa) and has a molar flow rate of 45.4 kgmol / h, and stream 182 is expanded to 1.3 bar (130 kPa) and has a flow of 182.7 kgmol / h. Both streams provide cooling in the pre-cooling heat exchanger and are recycled to the first and second stages (183B and 183A) of the mixed gas compressor.

[0055]

[0060] From the top of the first mixed refrigerant separator 20, the first mixed refrigerant vapor 129 containing 99.98% hydrogen exits, returns to the precooling heat exchanger 1, where it is further cooled to 110.9K to form the second cooled mixed refrigerant stream 130, which is supplied to the second mixed refrigerant separator 21. From the bottom of the second mixed refrigerant separator 21, the second mixed refrigerant liquid 184 containing most of the remaining propane and having a flow rate of only 0.3 kgmol / h exits, is expanded in a second mixed refrigerant liquid expansion device 48 such as a valve, and after cooling and reducing the pressure of the flow, it forms a part of the returning refrigerant stream 183B described above.

[0056]

[0061] From the top of the second mixed refrigerant separator 21, the second mixed refrigerant vapor 131 exits and is purified in a mixed refrigerant purifier 22 that removes any remaining propane, which is less than 1 ppm in this example. The purified hydrogen stream 132 exits the mixed refrigerant purifier 22, returns to the precooling heat exchanger 1, where it is cooled to 80.1K, exits as the cooled refrigerant 133, and this is further purified in the second refrigerant purifier 23. The second refrigerant purifier is similar to the mixed refrigerant purifier 22 except that it removes 1 ppm of nitrogen from the original hydrogen supply. The cryogenic refrigerant 134 leaves the second refrigerant purifier 23 and is supplied to the hydrogen liquefaction process.

[0057]

[0062] After circulation in a closed loop through the liquefaction process, the pure hydrogen cryogenic refrigerant returns as two separate streams, a low-pressure stream 141 and an intermediate-pressure stream 151. The low-pressure refrigerant 141 at 1.3 bar (130 kPa) is recycled from the hydrogen liquefaction process, enters the precooling heat exchanger 1 to provide cooling, and is returned to the first stage of the mixed gas compressor. The intermediate-pressure refrigerant 151 at 4.1 bar (410 kPa) leaves the hydrogen liquefaction process, enters the precooling heat exchanger 1 to provide cooling, and is returned to the second stage of the mixed gas compressor.

Table 1

Table 2

[0058]

[0063] While the preferred embodiments of the present disclosure have been illustrated and described, it will be apparent to those skilled in the art that various modifications and variations can be made therein without departing from the spirit of the present disclosure. The scope of the present disclosure is defined by the following claims.

Claims

1. A system for cooling a supply stream containing hydrogen or helium with a mixed refrigerant, comprising: a. A pre-cooling heat exchanger having a supply stream cooling passage, a first refrigerant cooling passage, a second refrigerant cooling passage, and a refrigerant heating passage; b. A compression system having an inlet in fluid communication with the refrigerant heating passage, configured to receive a refrigerant vapor stream composed of hydrogen and / or helium, which is mixed with at least one other refrigerant such that the molecular weight of the mixture is greater than 6 kg / kgmol, and increase its pressure, and having an outlet in fluid communication with the first refrigerant cooling passage; c. A first refrigerant separation device configured to receive fluid from the first refrigerant cooling passage in the pre-cooling heat exchanger, and having a liquid outlet and a vapor outlet in fluid communication with the refrigerant heating passage; d. A refrigerant purifier having a purifier inlet in fluid communication with the vapor outlet of the first refrigerant separation device and an outlet in fluid communication with the second refrigerant cooling passage, wherein the second refrigerant cooling passage has an outlet in fluid communication with the refrigerant heating passage. A system comprising the above components.

2. The system according to claim 1, wherein the compression system includes a first stage compressor having an inlet and an outlet in fluid communication with the refrigerant heating passage, a first stage aftercooler configured to receive fluid from the first stage compressor and having an inlet and an outlet, and a high-pressure accumulator having an inlet in fluid communication with the outlet of the first stage aftercooler, having a vapor outlet and a liquid outlet, wherein the vapor outlet is in fluid communication with the first refrigerant cooling passage and the liquid outlet is in fluid communication with the compression system.

3. The system according to claim 2, further comprising an inter-stage separation device having an inlet in fluid communication with the outlet of the first stage aftercooler, and having a vapor outlet in fluid communication with the high-pressure accumulator and a liquid outlet in fluid communication with the compression system.

4. The refrigerant heating passage includes a low-pressure refrigerant heating passage and an intermediate-pressure refrigerant heating passage, and the compression system includes a mixed gas compressor having an inlet configured to receive fluid from the low-pressure refrigerant heating passage, a mixed gas aftercooler having an inlet configured to receive fluid from the mixed gas compressor, a first inlet configured to receive fluid from the mixed gas aftercooler, a second inlet configured to receive fluid from the intermediate-pressure refrigerant heating passage, a third inlet, and a mixing device vapor outlet in fluid communication with the first inter-stage compressor, a second inter-stage compressor configured to receive fluid from the vapor outlet of the inter-stage separation device, and a second inter-stage aftercooler configured to receive fluid from the second inter-stage compressor and guide the fluid to the high-pressure accumulator. The system further includes a simultaneous heat and mass transfer control system for maintaining control of the composition and thermal characteristics of the mixed refrigerant vapor exiting the mixing device vapor outlet, and the simultaneous heat and mass transfer control system includes i) a mixing vessel valve having a valve inlet configured to receive fluid from the inter-stage separation device liquid outlet and the high-pressure accumulator liquid outlet, and a valve outlet configured to direct fluid to the third inlet of the mixing device when the mixing vessel valve is open. ii) the mixed gas aftercooler, and / or iii) at least one of the first and / or second inter-stage aftercoolers including at least one of them. The system according to claim 3.

5. The system according to claim 4, wherein the mixing device includes a liquid outlet in fluid communication with the low-pressure refrigerant heating passage and / or the intermediate-pressure refrigerant heating passage.

6. A pump having a pump inlet in fluid communication with the mixing device liquid outlet and a pump outlet in fluid communication with the low-pressure refrigerant heating passage and / or the intermediate-pressure refrigerant heating passage, and the system according to claim 5 further includes a pump included in the simultaneous heat and mass transfer control system.

7. The system according to claim 4, wherein the mixing device includes a heating coil, and the heating coil is included in the simultaneous heat and mass transfer control system.

8. The system according to claim 1, wherein the refrigerant purifier is selected from the group consisting of an adsorbent, a freezing device, and a distillation column.

9. The system according to claim 1, wherein the first refrigerant purifier regeneration stream is recycled to the compression system.

10. The system according to claim 9, wherein the second refrigerant purification regenerant stream is removed from the liquefaction process by being excluded or recycled upstream of the supply stream cooling passage of the pre-cooling heat exchanger.

11. The system according to claim 1, wherein the pre-cooling heat exchanger has at least one auxiliary refrigerant cooling passage and at least one auxiliary refrigerant heating passage.

12. The system according to claim 11, wherein at least a portion of the auxiliary refrigerant is used to provide refrigeration to an external process or system.

13. The system according to claim 1, wherein the supply stream and the mixed refrigerant are purified in a combined purifier, and the resulting purifier product is divided into a portion of the purifier product that is directed to the supply stream cooling passage and another portion that is directed to the compression system.

14. The system according to claim 1, further comprising a thermally insulated cold box having an interior and an exterior, wherein the pre-cooling heat exchanger is positioned within the interior of the cold box and the compression system is positioned outside the cold box.

15. The system according to claim 1, further comprising a primary refrigerant expansion device that operates below ambient temperature, receives primary refrigerant from the liquid outlet of the first refrigerant separation device, reduces the temperature and pressure of the received primary refrigerant such that expanded primary refrigerant is provided, and is configured to direct the expanded primary refrigerant to the refrigerant heating passage.

16. A method for liquefying a supply stream containing hydrogen or helium, comprising: a. mixing a hydrogen or helium refrigerant with at least one additional refrigerant component having a molecular weight higher than that of hydrogen or helium to form a mixed refrigerant having a molecular weight of at least 6 kg / kgmol; b. compressing the mixed refrigerant using a compression system including at least one dynamic compressor or dynamic compressor stage; c. separating the at least one additional refrigerant component from the hydrogen or helium refrigerant at a temperature of at least 75 K to obtain a remaining hydrogen or helium refrigerant; and d. cooling the hydrogen or helium supply stream using the remaining hydrogen or helium refrigerant to produce a liquid hydrogen or helium product from the supply stream containing hydrogen or helium. The method includes the above steps.

17. The method according to claim 16, wherein the at least one additional refrigerant component is selected from the group consisting of hydrocarbons, partially fluorinated hydrocarbons, and fully fluorinated hydrocarbons containing at least three carbon atoms or neon.

18. The method according to claim 16, wherein step c. is achieved using partial condensation and adsorption.

19. Step c. is achieved using partial condensation and at least two adsorption steps operating at different temperatures, wherein in the at least two adsorption steps, the at least one additional component is removed at a first temperature, and impurities in the feed stream containing the hydrogen or helium are removed at a second temperature lower than the first temperature, and further comprising the step of discharging the removed impurities. The method according to claim 16.

20. The method according to claim 16, further comprising the step of using the at least one additional refrigerant component separated in step c. to provide refrigeration to the feed stream containing the hydrogen or helium in a heat exchanger.

21. The method according to claim 20, further comprising the step of taking the refrigeration provided by the at least one additional refrigerant out of the heat exchanger to a second process.

22. The method according to claim 21, wherein the refrigeration provided by the at least one additional refrigerant is taken out of the heat exchanger using an auxiliary refrigerant stream below ambient temperature.

23. The method according to claim 20, wherein the step of using the at least one additional refrigerant component separated in step c. to provide refrigeration to the feed stream containing the hydrogen or helium in a heat exchanger includes the step of removing a two-phase flow from the heat exchanger.

24. The method according to claim 16, wherein the step of cooling the hydrogen or helium feed stream is performed in a heat exchanger located within a cold box, and the step of compressing the mixed refrigerant using a compression system is performed outside the cold box.

25. A system for cooling a cryogenic fluid feed stream containing hydrogen or helium with a mixed refrigerant, a. A precooling heat exchanger having a precooling feed stream cooling passage, a low-pressure refrigerant heating passage, an intermediate-pressure refrigerant heating passage, a first refrigerant cooling passage, and a second refrigerant cooling passage; b. A mixed gas compressor configured to receive a mixed refrigerant vapor stream from the low-pressure refrigerant heating passage; c. A mixed gas aftercooler in fluid communication with the mixed gas compressor; d. A mixing device having a first inlet, a second inlet, and a mixing device vapor outlet in fluid communication with the mixed gas aftercooler, wherein the second inlet is configured to receive a mixed refrigerant vapor flow from the intermediate pressure refrigerant heating passage; e. A first stage compressor in fluid communication with the mixing device vapor outlet; f. A first stage aftercooler in fluid communication with the first stage compressor; g. A high-pressure accumulator in fluid communication with the first stage aftercooler, having a high-pressure accumulator vapor outlet and a high-pressure accumulator liquid outlet, wherein the high-pressure accumulator vapor outlet is in fluid communication with the first refrigerant cooling passage, and the high-pressure accumulator liquid outlet is in fluid communication with the intermediate pressure refrigerant heating passage; h. A first refrigerant separation device in fluid communication with the first refrigerant cooling passage, having a first refrigerant separation device liquid outlet in fluid communication with the low-pressure refrigerant heating passage and a first refrigerant separation device vapor outlet in fluid communication with the second refrigerant cooling passage; i. A second refrigerant separation device in fluid communication with the second refrigerant cooling passage, having a second refrigerant separation device liquid outlet in fluid communication with the low-pressure refrigerant heating passage and a second refrigerant separation device vapor outlet; j. A refrigerant purifier having a purifier inlet in fluid communication with the second refrigerant separation device vapor outlet and a purifier outlet, wherein the purifier outlet is in fluid communication with the low-pressure refrigerant heating passage and the intermediate pressure refrigerant heating passage; A system comprising.

26. k. A liquefied supply flow cooling passage configured to receive a pre-cooled supply flow from the pre-cooled supply flow cooling passage, a liquefied low-pressure refrigerant heating passage configured to guide refrigerant to the low-pressure refrigerant heating passage of the pre-cooling heat exchanger, a liquefied intermediate pressure refrigerant heating passage configured to guide refrigerant to the intermediate pressure refrigerant heating passage of the pre-cooling heat exchanger, a third refrigerant cooling passage in fluid communication with the purifier outlet, and a fourth refrigerant cooling passage configured to receive a first refrigerant portion from the third refrigerant cooling passage; l. A first expansion device configured to receive a second refrigerant portion from the third refrigerant cooling passage and guide the expanded second refrigerant portion to the liquefied intermediate pressure refrigerant heating passage; m. A second expansion device configured to receive the cooled first refrigerant portion from the fourth refrigerant cooling passage and guide the expanded cooled first refrigerant portion to the liquefied low-pressure refrigerant heating passage The system according to claim 25, further comprising **Claim 27** The liquefaction heat exchanger includes a first liquefaction heat exchanger having the third refrigerant cooling passage and a second liquefaction heat exchanger including the fourth refrigerant cooling passage, and the liquefaction supply flow cooling passage, the liquefaction low-pressure refrigerant heating passage, and the liquefaction intermediate-pressure refrigerant heating passage pass through both the first liquefaction heat exchanger and the second liquefaction heat exchanger. The system according to claim 26. **Claim 28** The system further includes a recirculation passage extending through the liquefaction heat exchanger and the precooling heat exchanger, and further includes a product expansion device and a product separation device. The product expansion device is configured to receive a liquid product stream from the liquefaction supply flow cooling passage and guide the resulting expanded product fluid stream to the product separation device. The product separation device has a product separation device vapor outlet in fluid communication with the recirculation passage and the product separation device liquid outlet. The system according to claim 26. **Claim 29** The system according to claim 25, further comprising a refrigerant expansion device having an inlet in fluid communication with the liquid outlet of the high-pressure accumulator and an outlet in fluid communication with the intermediate-pressure refrigerant heating passage. **Claim 30** The system according to claim 25, wherein the mixing device includes a sparger and / or a heating coil. **Claim 31** The precooling heat exchanger further includes a first auxiliary refrigerant heating passage, a second auxiliary refrigerant heating passage, and an auxiliary refrigerant cooling passage. k. A first auxiliary refrigerant compressor configured to receive a first auxiliary refrigerant vapor stream from the first auxiliary refrigerant heating passage. l. A first auxiliary rear cooler in fluid communication with the first auxiliary refrigerant compressor. m. A second auxiliary refrigerant compressor in fluid communication with the first auxiliary rear cooler and configured to receive a second auxiliary refrigerant vapor stream from the second auxiliary refrigerant heating passage. n. A second auxiliary rear cooler in fluid communication with the second auxiliary refrigerant compressor and having a second auxiliary rear cooler outlet configured to direct fluid to the auxiliary refrigerant cooling passage. o. A third expansion device having a third expansion device inlet in fluid communication with the auxiliary refrigerant cooling passage and a third expansion device outlet in fluid communication with the second auxiliary refrigerant heating passage. p. A fourth expansion device having a fourth expansion device inlet in fluid communication with the auxiliary refrigerant cooling passage and a fourth expansion device outlet in fluid communication with the first auxiliary refrigerant heating passage The system according to claim 25, further comprising

32. The system according to claim 25, wherein the mixed gas compressor and the first inter-stage compressor are a dynamic compressor or a stage of a dynamic compressor.

33. The mixing device includes a mixing device liquid outlet, k. An inter-stage separation device having an inter-stage separation device vapor outlet and an inter-stage separation device liquid outlet, in fluid communication with the first inter-stage compressor; l. A second inter-stage compressor in fluid communication with the inter-stage separation device vapor outlet; m. A second inter-stage aftercooler having an inlet in fluid communication with the second inter-stage compressor and an outlet in fluid communication with the high-pressure accumulator The system further comprising n. The mixed device liquid outlet, the inter-stage separation device liquid outlet, and the high-pressure accumulator liquid outlet are configured to combine the liquids exiting the mixed device, the inter-stage separation device, and the high-pressure accumulator, such that a combined refrigerant liquid flow is formed and is directed to the low-pressure refrigerant heating passage and the intermediate-pressure refrigerant heating passage. The system according to claim 25.

34. The system according to claim 33, wherein the precooling heat exchanger includes a combined refrigerant liquid flow cooling passage, and the combined refrigerant liquid flow is cooled in the combined refrigerant liquid flow cooling passage before being directed to the low-pressure refrigerant heating passage.

35. The system according to claim 33, wherein the mixed gas compressor, the first inter-stage compressor, and the second inter-stage compressor are a dynamic compressor or a stage of a dynamic compressor.

36. The system according to claim 25, wherein the first refrigerant separation device liquid outlet is also in fluid communication with the intermediate-pressure refrigerant heating passage.

37. The system according to claim 36, further comprising a fifth expansion device configured to receive fluid from the first refrigerant separation device liquid outlet and direct the expanded fluid to the intermediate-pressure refrigerant heating passage, and a sixth expansion device configured to receive fluid from the first refrigerant separation device liquid outlet and direct the expanded fluid to the low-pressure refrigerant heating passage.

38. The system according to claim 25, further comprising a refrigerant purifier line that is in fluid communication with the refrigerant purifier and the mixed gas compressor and is configured such that a refrigerant purifier regeneration stream is recirculated from the refrigerant purifier to the compression system.

39. The pre-cooling heat exchanger further includes an auxiliary refrigerant heating passage and an auxiliary refrigerant cooling passage, k. An auxiliary refrigerant compressor configured to receive a first auxiliary refrigerant vapor stream from the auxiliary refrigerant heating passage; l. An auxiliary aftercooler having an inlet in fluid communication with the auxiliary refrigerant compressor and an outlet in fluid communication with the auxiliary refrigerant cooling passage; m. A third expansion device having an inlet in fluid communication with the auxiliary refrigerant cooling passage and a third expansion device outlet in fluid communication with the auxiliary refrigerant heating passage The system according to claim 25, further comprising.

40. The system according to claim 39, wherein the mixed gas compressor, the first inter-stage compressor, and the auxiliary refrigerant compressor are dynamic compressors or stages of a single dynamic compressor.

41. The system according to claim 25, wherein the refrigerant purifier is selected from the group consisting of an adsorbent, a freezing device, and a distillation column.

42. The system according to claim 25, wherein the refrigerant purifier is a freezing device.

43. The system according to claim 42, further comprising a refrigerant purifier line that is in fluid communication with the freezing device and the mixed gas compressor and is configured such that a refrigerant purifier regeneration stream is recirculated from the freezing device to the compression system.

44. The system according to claim 42, wherein the refrigerant purifier is a purifier heat exchanger.

45. The system according to claim 44, wherein the purifier heat exchanger is a brazed aluminum heat exchanger or a tube heat exchanger.

46. The system according to claim 44, wherein the purifier heat exchanger includes a filter configured to capture frozen high molecular weight substances.

47. The refrigerant purifier is a first refrigerant purifier having a first refrigerant purifier outlet, and further includes a second refrigerant purifier having a second refrigerant purifier inlet in fluid communication with the first refrigerant purifier outlet, the first refrigerant purifier being configured to remove higher molecular weight impurities having a boiling point exceeding 80K, and the second refrigerant purifier being configured to remove lighter molecular weight impurities. The system according to claim 25.

48. The system according to claim 47, wherein the impurities having a higher molecular weight than the above contain hydrocarbons, and the impurities having a lower molecular weight than the above contain nitrogen and / or argon.

49. The system according to claim 48, further comprising a refrigerant purifier line that is in fluid communication with the first refrigerant purifier and the mixed gas compressor and is configured such that a refrigerant purifier regeneration stream containing the impurities having a higher molecular weight than the above is recycled from the freezing device to the compression system.

50. The system according to claim 49, wherein the second refrigerant purifier is configured to exhaust the impurities having a lower molecular weight than the above to the atmosphere.

51. The system according to claim 47, further comprising a purified refrigerant cooling passage in the pre-cooling heat exchanger that is configured to receive fluid from the first refrigerant purifier outlet and direct the cooled fluid to the second refrigerant purifier inlet.

52. The system according to claim 25, wherein the refrigerant purifier is configured to remove nitrogen and / or argon impurities and hydrocarbon impurities from the refrigerant stream.

53. The system according to claim 52, further comprising a refrigerant purifier line that is in fluid communication with the refrigerant purifier and the mixed gas compressor and is configured such that a refrigerant purifier regeneration stream containing nitrogen and / or argon impurities and hydrocarbon impurities is recycled from the freezing device to the compression system.

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