Patent Application
20240393041
This application claims the benefit of priority under 35 U.S.C. § 119 (a) and (b) to French patent application No. FR2305241, filed May 26, 2023, which is herein incorporated by reference in its entirety.
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 known 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 known 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 known 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 known solutions exhibit a rather unsatisfactory energy performance.
One objective of this invention is to mitigate some or all of the drawbacks of the prior art as set out above.
To this end, the installation according to certain embodiments of the invention can include: a second pre-cooling device having a refrigeration cycle for a second cycle gas consisting/comprising of nitrogen, a first pre-cooling device 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 present invention also relates to a process for hydrogen liquefaction, comprising the following steps:
According to other possible distinctive features:
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.
Other features and advantages are set out in the description below, provided with reference to the figures in which:
Other features and advantages of the invention will become further apparent via, on the one hand, the following description and, on the other hand, several exemplary embodiments given by way of non-limiting indication and with reference to the attached schematic drawings, in which:
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 [
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 the first 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 the first 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 [
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 [
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, C5H10, 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% C5H10. 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 24%; 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 [
As illustrated in [
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 [
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 [
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).
While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed. Furthermore, if there is language referring to order, such as first and second, it should be understood in an exemplary sense and not in a limiting sense. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.
The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.
“Comprising” in a claim is an open transitional term which means the subsequently identified claim elements are a nonexclusive listing (i.e., anything else may be additionally included and remain within the scope of “comprising”). “Comprising” as used herein may be replaced by the more limited transitional terms “consisting essentially of” and “consisting of” unless otherwise indicated herein.
“Providing” in a claim is defined to mean furnishing, supplying, making available, or preparing something. The step may be performed by any actor in the absence of express language in the claim to the contrary.
Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.
Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value and/or to the other particular value, along with all combinations within said range.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR 2305241 | May 2023 | FR | national |
