AU2024202840A1

AU2024202840A1 - Installation and method for the liquefaction of hydrogen

Info

Publication number: AU2024202840A1
Application number: AU2024202840A
Authority: AU
Inventors: Gaertner Axelle; Guenego Bertille; Redon Emilien; Berry Lea; Morel Thomas
Original assignee: Air Liquide SA; LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Current assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date: 2023-05-26
Filing date: 2024-05-01
Publication date: 2024-12-12
Also published as: CA3236478A1; US20240393041A1; FR3149079A1; FR3149079B1

Abstract

The invention relates to an invention for the liquefaction of hydrogen, comprising a circuit (3) for supplying hydrogen to be cooled, a plurality of heat exchangers (4, 5, 6, 7, 17) arranged in heat exchange with the supply circuit (3), a first pre-cooling device (8), a second pre-cooling device (9) and a cooling system (10) in heat exchange with the set (4, 5) of exchangers, to reduce the temperature of the hydrogen to a temperature below the critical temperature of hydrogen, the first pre-cooling device (8) comprising a refrigerator having a closed refrigeration cycle for a first cycle gas comprising at least three components, a first centrifugal compressor (18), a cooling member (180), three phase separators (28, 48, 88) configured to separate the two-phase fluid, the refrigerator having a refrigeration cycle of the first pre cooling device (8) comprising a first expansion member (78) configured to expand the liquid produced by one of the phase separators (48) and to return this fluid to a first centrifugal compressor (18) via a passage through a heat exchanger of the set of exchangers. Figure for the abstract: Fig. 1 1/3 [Fig. 1] ISO 3 38 292 'o 111 123 30 [Fig. 2]

Description

1/3

[Fig. 1]

ISO 3 38

292

'o 111

123 30

[Fig. 2]

Installation and method for the liquefaction of hydrogen

This application claim priority from French Patent Application No. 2305241 filed on 26 May 2023, the contents of which are to be taken as incorporated herein by this reference. The invention relates to an installation and a method for the liquefaction of hydrogen. More particularly, the invention relates to a hydrogen liquefaction installation comprising a circuit for supplying hydrogen to be cooled, the circuit having an upstream end designed to be connected to a pressurized gaseous hydrogen source at a first initial temperature and a second end designed to be connected to at least one liquefied hydrogen collection member, the installation comprising a plurality of heat exchangers arranged in series, in heat exchange with the supply circuit, the installation comprising a first pre-cooling device in heat exchange with a first set of the heat exchanger(s), the first pre-cooling device being configured to reduce the temperature of the hydrogen from the first temperature to a second temperature which is lower than the first temperature and is between 120 K and 163 K, the installation comprising a second pre-cooling device in heat exchange with a second set of the heat exchangers and configured to reduce the hydrogen temperature from the second temperature to a third temperature below the second temperature and greater than or equal to 103 K, the installation comprising a cooling system in heat exchange with a third set of the heat exchangers and configured to reduce the temperature of the hydrogen from the third temperature to a fourth temperature, below the critical temperature of hydrogen, for example below 25 K. A hydrogen liquefier usually comprises a pre-cooling section for bringing the hydrogen to an intermediate temperature of about 80 K and a final section for cooling the hydrogen from about 80 K to 30 K. After being cooled in both sections, the hydrogen is liquefied. It is previously described to use a refrigerant, comprising a plurality of components including nitrogen and hydrocarbons, in a closed cycle for cooling the pre-cooling section. For hydrogen liquefaction it is previously described to provide liquefiers using a pre-cooling system and a cooling system (a refrigeration cycle comprising hydrogen and/or helium). The document "Optimal operation of large-scale liquid hydrogen plant utilizing mixed fluid refrigeration system" (Krasae et al. International Journal of Hydrogen Energy, Vol 39, no. 13, ISSN: 0360-3199) describes a liquefier in which the pre-cooling system consists of a mixed refrigerant (MR) cycle. This solution is unsatisfactory because it requires, notably, the use of a large number of components for the pre-cooling cycle.

Other previously described solutions consist in providing a pre-cooling system consisting of two cycles, namely a mixed refrigerant cycle and a nitrogen cycle. It is advantageous to carry out as much cooling as possible in the pre-cooling section, in order to limit the cooling to be carried out in the final section, where cooling is less effective because it is mostly based on the sensible heat of the hydrogen. Below a given temperature, there is a risk of demixing and/or freezing for the heaviest components of the cycle with the multi component refrigerant. For large-capacity hydrogen liquefiers, the previously described solutions exhibit a rather unsatisfactory energy performance. One aspect of this invention is to mitigate some or all of the drawbacks of the prior art as set out above. Another aspect of this invention relates to an installation for the liquefaction of hydrogen, comprising a circuit for supplying hydrogen to be cooled, having an upstream end designed to be connected to a source of gaseous hydrogen under pressure at a first initial temperature and a downstream end designed to be connected to at least one liquefied hydrogen collection member, the installation comprising a plurality of heat exchangers arranged in series in heat exchange with the supply circuit, the installation comprising a first pre-cooling device in heat exchange with a first set of the heat exchanger(s), the first pre-cooling device being configured to reduce the temperature of the hydrogen from the first temperature to a second temperature which is below the first temperature and is between 120 K and 163 K, the installation comprising a second pre-cooling device in heat exchange with a second set of the heat exchangers, configured to reduce the temperature of the hydrogen from the second temperature to a third temperature which is below the second temperature and is between 103 K and 80 K, the installation comprising a cooling system in heat exchange with a third set of the heat exchangers, configured to reduce the temperature of the hydrogen from the third temperature to a fourth temperature below the critical temperature of the hydrogen, below 25 K for example, wherein the second pre-cooling device comprises a refrigerator having a refrigeration cycle for a second cycle gas consisting of nitrogen, the first pre-cooling device comprising a refrigerator having a closed refrigeration cycle for a first cycle gas comprising at least three components including at least one first component that is more volatile than at least one second component, the at least one second component being more volatile than at least one third component, the refrigerator having a refrigeration cycle of the first pre-cooling device comprising a first centrifugal compressor for the first cycle gas, a cooling member for the compressed first cycle gas configured to produce a two-phase fluid, a first phase separator configured to separate the two-phase fluid, the second compression members configured to compress the gas and liquid from the first phase separator, a second phase separator configured to separate the two-phase fluid produced by the second compression members, a first duct in heat exchange with a heat exchanger of the first set and configured to cool and partially condense gas produced by the second phase separator and to transfer this partially condensed gas to a third phase separator of the refrigerator of the first pre-cooling device, the refrigerator having a refrigeration cycle of the first pre-cooling device comprising a first expansion member configured to expand the liquid produced by the second phase separator and to send this fluid to the first centrifugal compressor via a passage through a heat exchanger of the first set in which the refrigerator having a refrigeration cycle of the first pre-cooling device comprises a fourth phase separator configured to recover the liquid produced by the second phase separator and expanded by the first expansion member and to be additionally supplied with the liquid produced by the third phase separator. Another aspect of the invention relates to a method for the liquefaction of hydrogen, comprising the following steps: - cooling a flow of hydrogen, having a pressure of at least 20 bars abs and a first initial temperature, to a second temperature of 163 K or below in at least a first line of heat exchanger(s) cooled by a first pre-cooling device, - cooling the hydrogen flow from the second temperature to a third temperature of 103 K or below, in at least one heat exchanger cooled by a second pre-cooling device, - cooling the hydrogen flow from the third temperature to a temperature below the critical temperature of hydrogen, particularly below 25 K, in at least one heat exchanger cooled by a cooling system, and liquefying the hydrogen flow cooled to the temperature below the critical temperature in order to obtain a flow of liquid hydrogen, wherein the second pre-cooling device is a refrigerator having a refrigeration cycle for a second cycle gas consisting of nitrogen, - the first pre-cooling device being a refrigerator of a first closed refrigeration cycle using a first refrigerant fluid comprising at least three components, including at least a first component that is more volatile than at least a second component and at least a third component that is more volatile than the at least a second component, the first refrigeration cycle comprising at least two steps of partial condensation at different temperatures above the second temperature, to separate the first refrigerant fluid while producing a gas enriched in its more volatile components and a liquid enriched in its less volatile components, the first refrigeration cycle comprising:

- compression in a centrifugal compressor, where the whole flow of first refrigerant fluid is compressed from a pressure of between 1.1 bara and 10 bara, preferably between 1.5 and 6 bara, to a pressure of between 7 and 30 bara, preferably between 15 and 25 bara, - cooling of the first refrigerant fluid to form a two-phase fluid, - separation of this two-phase fluid in a first phase separator, - centrifugal compression of the gas from the first phase separator, and pressurization of the liquid from the first phase separator to a pressure of between 25 bara and 70 bara, preferably between 45 bara and 65 bara, - the sending of this compressed gas and this pressurized liquid to a second phase separator, and separation of the compressed gas and the pressurized liquid in the second phase separator to form a gas and a liquid, - cooling of this gas produced by the second phase separator in the first heat exchange line to at least the second temperature, in order to condense it partially, - the sending of this partially condensed gas to a third phase separator, - the cooling and expansion of the liquid formed in the second phase separator via a valve or a turbine to form an expanded fluid, and the return of this expanded fluid to the first heat exchange line to reheat it and form at least some of the fluid compressed in the centrifugal compressor, the method using a fourth phase separator receiving the liquid produced by the second phase separator and the liquid produced by the third phase separator. The installation according to the invention, although conforming to the generic definition given in the above preamble, is essentially characterized in that the second pre-cooling device comprises a refrigerator having a refrigeration cycle for a second cycle gas consisting of nitrogen, the first pre-cooling device comprising a refrigerator having a closed refrigeration cycle for a first cycle gas comprising at least three components, of which at least a first component is more volatile than at least a second component, the at least second component being more volatile than at least a third component, the refrigerator having a refrigeration cycle of the first pre-cooling device comprising a first centrifugal compressor for compressing the first cycle gas, a member for cooling the compressed first cycle gas, configured to produce a two-phase fluid, a first phase separator configured to separate the two-phase fluid, second compression members configured to compress the gas and the liquid from the first phase separator, a second phase separator configured to separate the two-phase fluid produced by the second compression members, and a first duct, in heat exchange with a heat exchanger of the first set and configured to cool and partially condense gas produced by the second phase separator and to transfer this partially condensed gas to a third phase separator of the refrigerator of the first pre-cooling device, the refrigerator having a refrigeration cycle of the first pre cooling device comprising a first expansion member configured to expand the liquid produced by the second phase separator and to send this fluid to the first centrifugal compressor via a passage through a heat exchanger of the first set. The combination of the first and second pre-cooling devices with the cooling system can improve the performance of the installation. In particular, the composition of the first cycle gas and the association of the three phase separators of the first pre-cooling device can improve the performance, notably in terms of energy, of the installation, while using a limited number of components in the first cycle gas. Additionally, embodiments of the invention may have one or more of the following features: - the refrigerator having a refrigeration cycle of the first pre-cooling device comprises a fifth phase separator, configured to receive the gas produced by the third phase separator of the refrigerator and expanded in an expansion member of the refrigerator of the first pre-cooling device, - the refrigerator having a refrigeration cycle of the first pre-cooling device comprises a fifth phase separator, configured to receive the gas produced by the third phase separator of the refrigerator and expanded in an expansion member of the refrigerator of the first pre-cooling device, - the first cycle gas consists of a mixture of three to six components chosen from among nitrogen, methane, ethane or ethylene, propane or propene, butane or butene, and pentane, - the refrigerator of the second pre-cooling device comprises, arranged in a cycle circuit, at least two centrifugal compressors in series, configured to compress the second cycle gas, at least one expansion turbine of the second cycle gas coupled to a rotating shaft which is preferably also coupled to a compressor, the cycle circuit further comprising a thermosiphon device comprising a phase separator reservoir configured to receive at least one flow of the second cycle gas expanded by the at least one expansion turbine and to return cycle gas toward the compressors, - the first cycle gas consists of a mixture composed of at least one light component chosen from the group comprising nitrogen and methane, at least one medium component chosen from the group comprising ethane, ethylene, propane, propene, butane, butene, and at least one heavy component which is pentane, or butane if the medium component is chosen from the group comprising ethane, ethylene, propane, and propene.

The present invention also relates to a process for hydrogen liquefaction, comprising the following steps: o cooling a flow of hydrogen, at not less than 20 bars abs and at a first initial temperature, to a second temperature of 163 K or below in at least a first heat exchanger line cooled by a first pre-cooling device, o cooling the hydrogen flow from the second temperature to a third temperature 103 K or below, in at least one heat exchanger cooled by a second pre-cooling device, o cooling the hydrogen flow from the third temperature to a temperature below the critical temperature of hydrogen, particularly below 25 K, in at least one heat exchanger cooled by a cooling system, and liquefying the hydrogen flow cooled to the temperature below the critical temperature in order to obtain a flow of liquid hydrogen, wherein the second pre-cooling device is a refrigerator having a refrigeration cycle for a second cycle gas consisting of nitrogen, o the first pre-cooling device being a refrigerator of a first closed refrigeration cycle using a first refrigerant fluid comprising at least three components, including at least a first component that is more volatile than at least a second component and at least a third component that is more volatile than the at least a second component, the first refrigeration cycle comprising at least two steps of partial condensation at different temperatures above the second temperature, to separate the first refrigerant fluid while producing a gas enriched in its more volatile components and a liquid enriched in its less volatile components, the first refrigeration cycle comprising: o compression in a centrifugal compressor, where the whole flow of first refrigerant fluid is compressed from a pressure of between 1.1 bara and 10 bara, preferably between 1.5 and 6 bara, to a pressure of between 7 and 30 bara, preferably between 15 and 25 bara, o cooling of the first refrigerant fluid to form a two-phase fluid, o separation of this two-phase fluid in a first phase separator, o centrifugal compression of the gas from the first phase separator, and pressurization of the liquid from the first phase separator to a pressure of between 25 bar and 70 bar, preferably between 45 bar and 65 bar, o the sending of this compressed gas and this pressurized liquid to a second phase separator, and separation of the compressed gas and the pressurized liquid in the second phase separator to form a gas and a liquid, o the cooling of this gas produced by the second phase separator in the first heat exchange line to at least the second temperature, in order to condense it partially, o the sending of this partially condensed gas to a third phase separator, o the cooling and expansion of the liquid formed in the second phase separator via a valve or a turbine to form an expanded fluid, and the return of this expanded fluid to the first heat exchange line to reheat it and form at least some of the fluid compressed in the centrifugal compressor. According to other possible distinctive features: - the method uses a fourth phase separator receiving the liquid produced by the second phase separator and the liquid produced by the third phase separator, - the method uses a fifth phase separator receiving the gas produced by the third phase separator and expanded, - the first cycle gas consists of a mixture of three to six components chosen from among nitrogen, methane, ethane or ethylene, propane or propene, butane or butene, and pentane, - the first cycle gas comprises, in moles, between 10% and 50% light component(s), between 30% and 70% medium component(s) and 10% and 35% heavy component(s), the total being equal to 100%, - - the gas supplied by the second phase separator contains, in moles, less than 20% heavy component(s) and possibly at least 20% light component(s), - the liquid supplied by the second phase separator contains at least 20% heavy component(s) and possibly less than 20% light component(s), - the gas supplied by the third phase separator contains less than 1% heavy component(s) and preferably at least 30% light component(s), - the liquid supplied by the third phase separator contains at least 5% heavy component(s) and preferably less than 30% light component(s), - the gas supplied by the second phase separator is cooled in the first heat exchanger line to a temperature of between 10°C and -40°C, and preferably between +5°C and -20°C (or alternatively cooled between 120 K and 163 K) and supplies the third phase separator at this temperature,

- the liquid supplied by the second phase separator is cooled to a temperature of between 30°C and -160°C, preferably between -50°C and -110°C, - the liquid supplied by the third phase separator is cooled in the first heat exchanger line to a temperature of not more than -50°C and is partially condensed before being sent to the fourth phase separator, - the cooling of the hydrogen flow from the second temperature to a third temperature and/or the cooling of the hydrogen flow from the third temperature to a temperature below the critical temperature of hydrogen comprises a cooling of the hydrogen flow to an intermediate temperature of between 113 K and 153 K, preferably between 123 K and 143 K, at which the hydrogen flow is sent to an adsorption purification unit operating at a cryogenic temperature, and then, if necessary, to a catalytic conversion unit for converting ortho hydrogen to para hydrogen, in order to produce a hydrogen flow having a para hydrogen content of between 30% and 55% before being re-cooled, - the method comprises the production of pre-cooling power by the second pre-cooling device

with the following steps: centrifugal compression of the second cycle gas in at least two compressors arranged in series, from an inlet pressure of between 1 and 5 bara to a pressure of between 10 and 50 bara and preferably between 15 and 25 bara, and expansion of the compressed second cycle gas at a temperature of between 173 K and 128 K in at least one valve or turbine to a pressure of between 1.1 and 2 bara, at least one expansion turbine providing mechanical work if necessary for driving at least one compressor, - the production of pre-cooling power by the second pre-cooling device comprises a transfer

of the expanded second cycle gas to a phase separator reservoir of a thermosiphon device and a return of the cycle gas from the reservoir to the intake of the compressors, - the expansion of the compressed second cycle gas to a pressure of between 1.1 and 2 bara is carried out in two expansion turbines in series, the pressure of the second cycle gas entering the first of the turbines being between 15 and 50 bara, the temperature of the second cycle gas entering the second of the turbines preferably being between 143 K and 103 K, - the first cycle gas consists of a mixture of three components: CH4, C2H6 or C3H8, C5H10, for example, expressed in moles as 53% CH4, 41% C3H8,, 6% C5H10, or the first cycle gas consists of a mixture of four components from among: CH4 and/or N2, C2H6 and/or C3H8, C5H10, for example, expressed in moles as 49% CH4, 11% C2H6, 31% C3H8 and 9% C5H10, or the first cycle gas consists of a mixture of CH4, C2H4, C3H8 and C5H12, for example, in respective proportions in moles of 24%, 39%, 22%, and 15%, or in respective proportions in moles of 6%, 33%, 26%,35%, or the first cycle gas consists of a mixture of five components: N2; CH4, C2H6; C3H8; C5H10 for example, in respective proportions in moles of 3%; 37%, 32%, 13% and 14% or in respective proportions in moles of 3%, 31%, 34%, 18%, 14%, or in respective proportions in moles of 3%, 33%, 37%, 13%, and 14%, - the cut-off temperature between the first (8) pre-cooling device and the second (9) pre cooling device, that is to say the temperature of the hydrogen flow between these two pre cooling portions, is between 148 K and 123 K, preferably between 138 K and 133 K. The invention may also relate to any alternative device or method comprising any combination of the features above or below within the scope of the claims. Unless the context requires otherwise, where the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification (including the claims), they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components, or group thereof. The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application. Other features and advantages are set out in the description below, provided with reference to the figures in which: Brief description of the figures The invention will be better understood upon reading the following description, which is given solely by way of example and with reference to the appended drawings, in which:

[Fig. 1] is a partial and schematic view illustrating a first example of the structure and operation of an installation according to the invention,

[Fig. 2] is a partial and schematic view illustrating a second example of the structure and operation of an installation according to the invention.

[Fig. 3] is a partial and schematic view illustrating the structure and operation of a detail of a liquefaction installation according to the invention, illustrating a first possible embodiment of a second pre-cooling device,

[Fig. 4] is a partial and schematic view illustrating the structure and operation of a detail of a liquefaction installation according to the invention, illustrating a second possible embodiment of a second pre-cooling device. Detailed description

Throughout the figures, the same reference signs relate to the same elements. In this detailed description, the following embodiments are examples. Although the description refers to one or more embodiments, this does not mean that the features apply only to a single embodiment. Individual features of different embodiments can also be combined and/or interchanged in order to provide other embodiments. The hydrogen liquefaction installation 1 illustrated in [Fig. 1] comprises a circuit 3 for supplying hydrogen to be cooled, having an upstream end designed to be connected to a source 2 of gaseous hydrogen under pressure at a first initial temperature, and a downstream end 23 designed to be connected to at least one liquefied hydrogen collection member 30. The gaseous hydrogen source 2 may comprise, for example, an electrolyzer. The hydrogen collection member 30 may comprise, for example, at least one cryogenic storage unit. The installation 1 preferably comprises a plurality of heat exchangers 4, 5, 6, 7, 17 arranged in series, in heat exchange with the supply circuit 3. The installation 1 comprises a first pre-cooling device 8 in heat exchange with a first set 4, 5 of the heat exchangers (in this illustrated example, the first two heat exchangers 4 and 5). The first pre-cooling device 8 is configured to produce and supply a cold power and to transfer it to the supply circuit 3 in order to reduce the hydrogen temperature from the first temperature to a second temperature below the first temperature and not higher than 163 K, for example to 120 K (the second temperature being between 120 K and 163 K, for example). The installation 1 comprises a second pre-cooling device 9 in heat exchange with a second set 4, 5, 6 of the heat exchangers (in this illustrated example, the first three heat exchangers 4, 5 and 6). The second pre-cooling device 9 is configured to produce and supply a cold power and to transfer it to the supply circuit 3 in order to reduce the hydrogen temperature from the second temperature to a third temperature below the second temperature and not higher than 103 K, for example to 80 K (the second temperature being between 113 K and 65 K, or preferably between 103 K and 80 K, for example). The second pre-cooling device 9 is refrigerator having a refrigeration cycle for a second cycle gas consisting of nitrogen (that is to say, essentially nitrogen, possibly with traces of impurities). As illustrated, the installation 1 further comprises a cooling system 10 in heat exchange with a third set 4, 5, 6, 7, 17 of the heat exchangers (in this illustrated example, five heat exchangers). The cooling system 10 is a cryogenic refrigerator configured to produce a cold power at one or more cold ends of its cycle, and to supply this cold power for the purpose of reducing the temperature of the hydrogen from the third temperature to a fourth temperature below the critical temperature of hydrogen, for example below 25 K.

The first pre-cooling device 8 is a refrigerator having a closed refrigeration cycle for a first cycle gas comprising at least three components (mixed refrigerants (MR)), of which at least one first component is more volatile than at least one second component, the at least one second component being more volatile than at least one third component. This refrigerator having a refrigeration cycle of the first pre-cooling device 8 comprises at least a first centrifugal compressor 18 for the first cycle gas and a cooling member 180 for the compressed first cycle gas (for example, a heat exchanger cooled by a heat transfer fluid such as water, for example). The compressed and cooled first cycle gas produces a two-phase fluid. The first pre-cooling device 8 (or refrigerator 8) comprises a first phase separator 28 configured to separate this two phase fluid. The first pre-cooling device 8 comprises ducts transferring the gas and liquid produced by the first phase separator 28 to second respective compression members 38, 58 (a compressor 38 and a pump 58) configured to compress, respectively, the gas and the liquid from the first phase separator 28. Preferably, the compression 38 of the gas from the first phase separator 28 is of the centrifugal type. This compression 38 and the pressurization 58 of the liquid from the first phase separator 28 can bring the fluids to a pressure of between 25 bara and 70 bar, or preferably between 45 bara and 65 bara. The cycle circuit 21 of thefirst pre-cooling device 8 comprises a second phase separator 48 configured to receive the flows of fluids produced by the second compression members 38, 58 and to separate the resulting two-phase fluid. The cycle circuit 21 of thefirst pre-cooling device 8 comprises a first duct 68 having an upstream end connected to the gas part of the second phase separator 48. This first duct 68 is in heat exchange with at least one heat exchanger 4, 5 of the first set of exchangers, and is configured to cool and partially condense gas produced by the second phase separator 48. A downstream end of this first duct 68 is connected to a third separator 88 of the cycle circuit of the first pre-cooling device 8 so as to transfer this partially condensed gas to it (via an expansion valve 188 if necessary). For example, the gas supplied by the second phase separator 48 is cooled in the first line 68 of heat exchanger(s) 4, 5 to a temperature of between 120 K and 163 K. In the embodiment of

[Fig. 1], the third separator 88 operates at a temperature below the temperature of the fourth separator 108. The cycle circuit 21 of the first pre-cooling device 8 comprises a second duct 98 having an upstream end connected to the liquid part of the second phase separator 48. This second duct 98 is in heat exchange with at least one heat exchanger 4, 5 of the first set of exchangers. The liquid supplied by the second phase separator 48 is, for example, cooled to a temperature of between -30°C and -160°C, preferably between -50°C and -110°C.

This second duct 98 preferably comprises a first expansion member 78 such as a valve configured to expand the liquid produced by the second phase separator 48 before this fluid is returned to the first centrifugal compressor 18 by passing through a heat exchanger of the first set 4, 5. As illustrated in [Fig. 1] and described in greater detail below, after expanding in the first expansion member 78 and before returning to the heat exchanger(s) 4, 5, the liquid supplied by the second phase separator 48 can pass through a fourth phase separator 108, if present, in the cycle circuit of the first pre-cooling device 8. As described above, the fourth phase separator 108, if present, can be configured to recover the liquid produced by the second phase separator 48 and expanded by the first expansion member 78, and to be supplied, additionally, with the liquid produced by the third phase separator 88 via an appropriate duct. For example, the liquid supplied by the third phase separator 88 is cooled in the exchanger(s) 5 (first heat exchanger line 4) to a temperature of not more than -50°C, and is partially condensed before being sent to the fourth phase separator 108. The first cycle gas consists of a mixture of three to six components chosen from among nitrogen, methane, ethane or ethylene, propane or propene, butane or butene, and pentane. This first cycle gas consists of a mixture composed of at least one light component chosen from the group comprising nitrogen and methane, at least one medium component chosen from the group comprising ethane, ethylene, propane, propene, butane and butene, and at least one heavy component which is pentane, or butane if the medium component is chosen from the group comprising ethane, ethylene, propane and propene. The first cycle gas comprises, for example, in moles, between 10% and 50% light component(s), between 30% and 70% medium component(s) and 10% and 35% heavy component(s), the total being equal to 100%. Thus, in operation, the whole flow of first refrigerant fluid can be compressed 18 from a pressure of between 1.1 bara and 10 bara, preferably between 1.5 and 6 bara, to a pressure of between 7 and 30 bara, preferably between 15 and 25 bara. The gas supplied by the second phase separator 48 can advantageously contain, in moles, less than 20% heavy component(s) and possibly less than 20% light component(s). Similarly, the liquid supplied by the second phase separator 48 can contain at least 20% heavy component(s) and possibly less than 20% light component(s). Similarly, the gas supplied by the third phase separator 88 can contain less than 1% heavy component(s) and preferably at least 30% light component(s).

Additionally, the liquid supplied by the third phase separator 88 can contain at least 5% heavy component(s) and preferably less than 30% light component(s). If the first cycle gas consists of a mixture of three components, namely: CH4, C2H6 or C3H8, C5H1, it may be composed in the following proportions, expressed in moles: 53% CH4; 41% C3H8, 6% C5H10. If the first cycle gas consists of a mixture of four components, from among: CH4 and/or N2, C2H6 and/or C3H8, C5H10, it may be composed of the following proportions, expressed in moles: 49% CH4; 11% C2H6,31% C3H8 and 9% C5H1O. Alternatively, the first cycle gas can consist of a mixture of four components, from among: CH4; C2H4, C3H8 and C5H12, for example in respective proportions in moles of 2 4 %; 39%, 22%, and 15%, or in respective proportions in moles of 6%, 33%, 26%, 35%. If the first cycle gas consists of a mixture of five components from among the following, or the first cycle gas consists of a mixture of these five components: N2, CH4, C2H6; C3H8; C5H10, it may be composed in the following respective proportions, expressed in moles: 3%; 37%, 32%, 13% and 14%, or in respective proportions of 3%, 31%, 34%, 18%, 14%, or in respective proportions of 3%, 33%, 37%, 13% and 14%. This structure of the first pre-cooling device 8 provides energy efficiency with a limited number of components of the mixture forming the first cycle gas. The second pre-cooling device 9 for a nitrogen cycle is shown schematically in [Fig. 1] and may have any appropriate structure and mode of operation. For example, the nitrogen undergoes a thermodynamic cycle with compression followed by cooling 4, 5, then expansion (in valve(s) or turbine(s)) 29 and reheating 6, 5, 4. As illustrated in [Fig. 3], the second pre-cooling device 9 may comprise, or consist of, a refrigerator with a cycle circuit. This cycle circuit may comprise at least two centrifugal compressors 19 in series, configured to compress the second cycle gas (nitrogen). The compression inlet pressure may be between 1 and 5 bara, and the outlet pressure may be between 10 and 50 bara, preferably between 15 and 25 bara. After passing through one or more exchanges 4, 5 of the installation, the nitrogen, having been compressed and cooled (to a temperature of between 173 K and 128 K, for example) can be expanded in at least one expansion turbine 29, which can be coupled to a rotating shaft, also coupled to a compressor 19 of the cycle. The nitrogen is, for example, expanded to a pressure of between 1.1 and 2 bara. This first pre-cooling device 9 may further comprise a thermosiphon device comprising a phase separator reservoir 39 configured to receive at least one flow of the second cycle gas expanded by the at least one expansion turbine 29, and to return cycle gas to the compressors 19 (via a counter-current passage through the exchanger(s) 6, 5, 4 for reheating). As illustrated, the separator reservoir 39 may also be supplied with fluid drawn from the cycle before the expansion 29. At this point, the nitrogen is, for example, at a temperature of between -130°C and -145°C. The embodiment of the second pre-cooling device 9 illustrated in [Fig. 4] differs from that of

[Fig. 3] solely in that the refrigerator comprises three centrifugal compressors 19 in series and two expansion turbines 29 in series. The first and second turbines 29 can be coupled to the second and third compressors 19 respectively. At the inlet of the first turbine 29, the nitrogen is, for example, at a temperature of between 100 and -130°C. At the outlet of the second turbine 29, the nitrogen is, for example, at a temperature of between -130 and -170°C. In operation, the cooling of the hydrogen 3 from the second temperature to the third temperature and/or the cooling of the hydrogen flow 3 from the third temperature to a temperature below the critical temperature of the hydrogen can include cooling to an intermediate temperature of between 113 K and 153 K, preferably between 123 K and 143 K. At this intermediate temperature, the hydrogen flow can be sent to an adsorption purification unit 11 operating at a cryogenic temperature, and then, if necessary, to a unit for the catalytic conversion of ortho hydrogen to para hydrogen, to produce a hydrogen flow having a para hydrogen content of between 30% and 55% before being re-cooled. This partially converted hydrogen can continue to be cooled by the cooling system 10 until it reaches liquefaction. It can be converted (from ortho to para) again along the downstream line of heat exchanger(s) (7). It can undergo a final expansion 100 downstream (valve(s) or turbine(s)). The embodiment of [Fig. 2] differs from that of [Fig. 1] solely in that the refrigerator having a refrigeration cycle of the first pre-cooling device 8 comprises a fifth phase separator 118. The cycle circuit is configured so that the fifth phase separator 118 is supplied with the gas produced by the third phase separator 88 of the refrigerator via a heat exchange with at least one heat exchanger 4, 5 and expanded in an expansion member 128. As illustrated, the gas and the liquid produced by the fifth phase separator 118 can supply the fourth phase separator 108 via a heat exchange with at least one heat exchanger 5. In this embodiment, for example, the gas supplied by the second phase separator 48 is cooled in the first line 68 of heat exchanger(s) 4 to a temperature of between 10°C and -40°C, and preferably between +5°C and -20°C, and supplies the third phase separator 88 at this temperature. In this embodiment, the fifth separator 118 operates at a lower temperature than the fourth separator 108, which itself operates at a lower temperature than the third separator 88. The cooling system 10 is illustrated schematically for the sake of simplicity. It may be composed of a cryogenic cycle radiator in which the cycle gas comprises, or consists of, at least one of hydrogen and helium. The cycle gas is subjected to a thermodynamic cycle (compression 101, cooling 4, 5, 6, expansion 102, heating 7, 6, 5, 7) to supply cold power at least at one end of the cycle. Any or all of the heat exchangers 4, 5, 6, 7, 17 can be multipass exchangers (co-current or counter-current) to provide simultaneous heating and cooling of the flow or flows. At least the cold parts of the first and second pre-cooling devices can be placed in a first insulated cold box. At least the cold parts of the cooling device can be placed in a second insulated cold box. The cut-off temperature between the first pre-cooling device 8 and the second pre-cooling device 9, that is to say the temperature of the hydrogen flow between these two pre-cooling portions, can be between 148 K and 123 K, preferably between 138 K and 133 K. The cut-off temperature between the first pre-cooling device 9 and the second pre-cooling device 10, that is to say the temperature of the hydrogen flow between these two pre-cooling portions, can be between 93 K and 73 K, preferably between 88 K and 81 K. The centrifugal compression or compressions can have a plurality of compression stages. The expansion or expansions can be provided by valve(s) and/or turbine(s). In the illustrated example, the pre-cooling and the cooling consist of two pre-cooling devices 8, 9 and a cooling device 10. Evidently, other cooling devices (and pre-cooling devices if necessary) can be envisaged (refrigeration loop(s), for example).

Claims

The claims defining the invention are as follows: 1. Installation for the liquefaction of hydrogen, comprising a circuit for supplying hydrogen to be cooled, having an upstream end designed to be connected to a source of gaseous hydrogen under pressure at a first initial temperature and a downstream end designed to be connected to at least one liquefied hydrogen collection member, the installation comprising a plurality of heat exchangers arranged in series in heat exchange with the supply circuit, the installation comprising a first pre-cooling device in heat exchange with a first set of the heat exchanger(s), the first pre-cooling device being configured to reduce the temperature of the hydrogen from the first temperature to a second temperature which is below the first temperature and is between 120 K and 163 K, the installation comprising a second pre-cooling device in heat exchange with a second set of the heat exchangers, configured to reduce the temperature of the hydrogen from the second temperature to a third temperature which is below the second temperature and is between 103 K and 80 K, the installation comprising a cooling system in heat exchange with a third set of the heat exchangers, configured to reduce the temperature of the hydrogen from the third temperature to a fourth temperature below the critical temperature of the hydrogen, below 25 K for example, wherein the second pre-cooling device comprises a refrigerator having a refrigeration cycle for a second cycle gas consisting of nitrogen, the first pre-cooling device comprising a refrigerator having a closed refrigeration cycle for a first cycle gas comprising at least three components including at least one first component that is more volatile than at least one second component, the at least one second component being more volatile than at least one third component, the refrigerator having a refrigeration cycle of the first pre-cooling device comprising a first centrifugal compressor for the first cycle gas, a cooling member for the compressed first cycle gas configured to produce a two-phase fluid, a first phase separator configured to separate the two-phase fluid, the second compression members configured to compress the gas and liquid from thefirst phase separator, a second phase separator configured to separate the two-phase fluid produced by the second compression members, a first duct in heat exchange with a heat exchanger of the first set and configured to cool and partially condense gas produced by the second phase separator and to transfer this partially condensed gas to a third phase separator of the refrigerator of the first pre cooling device, the refrigerator having a refrigeration cycle of the first pre-cooling device comprising a first expansion member configured to expand the liquid produced by the second phase separator and to send this fluid to the first centrifugal compressor via a passage through a heat exchanger of the first set in which the refrigerator having a refrigeration cycle of the first pre-cooling device comprises a fourth phase separator configured to recover the liquid produced by the second phase separator and expanded by the first expansion member and to be additionally supplied with the liquid produced by the third phase separator.
2. Installation according to Claim 1, characterized in that the refrigerator having a refrigeration cycle of the first pre-cooling device comprises a fifth phase separator, configured to receive the gas produced by the third phase separator of the refrigerator and expanded in an expansion member of the refrigerator of the first pre-cooling device.
3. Installation according to any one of Claims 1 to 2, wherein the first cycle gas consists of a mixture of three to six components chosen from among nitrogen, methane, ethane or ethylene, propane or propene, butane or butene, and pentane.
4. Installation according to any one of Claims I to 3, wherein the refrigerator of the second pre-cooling device comprises, arranged in a cycle circuit, at least two centrifugal compressors in series, configured to compress the second cycle gas, at least one expansion turbine of the second cycle gas coupled to a rotating shaft which is preferably also coupled to one of the compressors, the cycle circuit further comprising a thermosiphon device comprising a phase separator reservoir configured to receive at least one flow of the second cycle gas expanded by the at least one expansion turbine and to return cycle gas to the compressors.
5. Method for the liquefaction of hydrogen, comprising the following steps: - cooling a flow of hydrogen, having a pressure of at least 20 bars abs and a first initial temperature, to a second temperature of 163 K or below in at least a first line of heat exchanger(s) cooled by a first pre-cooling device, - cooling the hydrogen flow from the second temperature to a third temperature of 103 K or below, in at least one heat exchanger cooled by a second pre-cooling device, - cooling the hydrogen flow from the third temperature to a temperature below the critical temperature of hydrogen, particularly below 25 K, in at least one heat exchanger cooled by a cooling system, and liquefying the hydrogen flow cooled to the temperature below the critical temperature in order to obtain a flow of liquid hydrogen, wherein the second pre-cooling device is a refrigerator having a refrigeration cycle for a second cycle gas consisting of nitrogen, - the first pre-cooling device being a refrigerator of a first closed refrigeration cycle using a first refrigerant fluid comprising at least three components, including at least a first component that is more volatile than at least a second component and at least a third component that is more volatile than the at least a second component, the first refrigeration cycle comprising at least two steps of partial condensation at different temperatures above the second temperature, to separate the first refrigerant fluid while producing a gas enriched in its more volatile components and a liquid enriched in its less volatile components, the first refrigeration cycle comprising: - compression in a centrifugal compressor, where the whole flow of first refrigerant fluid is compressed from a pressure of between 1.1 bara and 10 bara, preferably between 1.5 and 6 bara, to a pressure of between 7 and 30 bara, preferably between 15 and 25 bara, - cooling of the first refrigerant fluid to form a two-phase fluid, - separation of this two-phase fluid in a first phase separator, - centrifugal compression of the gas from the first phase separator, and pressurization of the liquid from the first phase separator to a pressure of between 25 bara and 70 bara, preferably between 45 bara and 65 bara, - the sending of this compressed gas and this pressurized liquid to a second phase separator, and separation of the compressed gas and the pressurized liquid in the second phase separator to form a gas and a liquid, - cooling of this gas produced by the second phase separator in the first heat exchange line to at least the second temperature, in order to condense it partially, - the sending of this partially condensed gas to a third phase separator, - the cooling and expansion of the liquid formed in the second phase separator via a valve or a turbine to form an expanded fluid, and the return of this expanded fluid to the first heat exchange line to reheat it and form at least some of the fluid compressed in the centrifugal compressor, the method using a fourth phase separator receiving the liquid produced by the second phase separator and the liquid produced by the third phase separator.
6. Method according to Claim 5, wherein it uses a fifth phase separator receiving the gas produced by third phase separator and expanded.
7. Method according to any one of Claims 5 to 6, wherein the first cycle gas consists of a mixture of three to six components chosen from among nitrogen, methane, ethane or ethylene, propane or propene, butane or butene, and pentane.
8. Method according to any one of Claims 5 to 7, wherein the first cycle gas consists of a mixture composed of at least one light component chosen from the group of: nitrogen and methane, at least one medium component chosen from the group of: ethane, ethylene, propane, propene, butane, butene, and at least one heavy component which is pentane, or butane if the medium component is chosen from the group of: ethane, ethylene, propane, and propene.
9. Method according to Claim 8, wherein the first cycle gas comprises, in moles, between 10% and 50% light component(s), between 30% and 70% medium component(s) and 10% and 35% heavy component(s), the total being equal to 100%.
10. Method according to any one of Claims 5 to 9, wherein the cooling of the hydrogen flow from the second temperature to a third temperature comprises a cooling of the hydrogen flow to an intermediate temperature of between 113 K and 153 K, preferably between 123 K and 143 K, at which the hydrogen flow is sent to an adsorption purification unit operating at a cryogenic temperature, and then, if necessary, to a catalytic conversion unit for converting ortho hydrogen to para hydrogen, in order to produce a hydrogen flow having a para hydrogen content of between 30% and 55% before being re-cooled.
11. Method according to any one of Claims 5 to 10, comprising the production of pre cooling power by the second pre-cooling device with the following steps: centrifugal compression of the second cycle gas in at least two compressors arranged in series, from an inlet pressure of between 1 and 5 bara to a pressure of between 10 and 50 bara and preferably between 15 and 25 bara, and expansion of the compressed second cycle gas at a temperature of between 173 K and 128 K in at least one valve or turbine to a pressure of between 1.1 and 2 bara, at least one expansion turbine providing mechanical work if necessary for driving at least one compressor.
12. Method according to Claim 11, wherein the production of pre-cooling power by the second pre-cooling device comprises a transfer of the expanded second cycle gas to a phase separator reservoir of a thermosiphon device and a return of the cycle gas from the reservoir to the intake of the compressors.
13. Method according to Claim 11 or Claim 12, wherein the expansion of the compressed second cycle gas to a pressure of between 1.1 and 2 bara is carried out in two expansion turbines in series, the pressure of the second cycle gas entering the first of the turbines being between 15 and 50 bara, the temperature of the second cycle gas entering the second of the turbines preferably being between 143 K and 103 K.
14. Method according to any one of Claims 5 to 13, wherein the first cycle gas consists of a mixture of three components: CH4, C2H6 or C3H8, C5H10, for example, expressed in moles as 53% CH4, 41% C3H8,, 6% C5H10, or the first cycle gas consists of a mixture of four components fromamong: CH4 and/orN2, C2H6 and/orC3H8, C5H10, forexample, expressed in moles as 49% CH4, 11% C2H6, 31% C3H8 and 9% C5H10, or the first cycle gas consists of a mixture of CH4, C2H4, C3H8 and C5H12, for example, in respective proportions in moles of 24%, 39%, 22%, and 15%, or in respective proportions in moles of 6%, 33%, 26%,35%, or the first cycle gas consists of a mixture of five components: N2; CH4, C2H6; C3H8; C5H10 for example, in respective proportions in moles of 3%; 37%, 32%, 13% and 14% or in respective proportions in moles of 3%, 31%, 34%, 18%, 14%, or in respective proportions in moles of 3%, 33%,37%,13%, and 14%.
15. Method according to any one of Claims 5 to 14, wherein the cut-off temperature between the first pre-cooling device and the second pre-cooling device, that is to say the temperature of the hydrogen flow between these two pre-cooling portions, is between 148 K and 123 K, preferably between 138 K and 133 K.
16. Method according to any one of Claims 5 to 15, wherein the cut-off temperature between the second pre-cooling device and the cooling system, that is to say the temperature of the hydrogen flow between these two pre-cooling portions, is between 93 K and 73 K, preferably between 88 K and 81 K.