WO2022254132A1

WO2022254132A1 - Method and plant for hydrogen liquefaction

Info

Publication number: WO2022254132A1
Application number: PCT/FR2022/051005
Authority: WO
Inventors: Florian JALIA; Rémi LINOTTE; Hamza FILALI; Davide DURI; Loïc PENIN; Pierre CHABERNAUD
Original assignee: Engie; Arianegroup Sas
Priority date: 2021-05-31
Filing date: 2022-05-27
Publication date: 2022-12-08
Also published as: FR3123420A1; FR3123420B1; AU2022285918A1; BR112023025068A2; EP4348138A1

Abstract

Method for hydrogen liquefaction comprising at least a pre-cooling step, wherein a hydrogen feed flow is cooled by a first refrigerant, a cooling step, wherein the hydrogen feed flow is cooled by a second refrigerant, and a step of expanding the hydrogen feed flow. Each of the first and second refrigerants is successively subjected to at least one compression and to at least one expansion in order to cool it, and a liquid phase of the first refrigerant cools the second refrigerant between at least three stages of said compression so that the second refrigerant does not exceed a temperature of 150 K, preferably 113 K, during said compression of the second refrigerant. A plant for the implementation of this method comprises a first refrigerant circuit (R1) containing a first refrigerant and a second refrigerant circuit (R2) containing a second refrigerant and comprising one or more compressors (C21, C22, C23) and a cooling device arranged together, and one or more expansion valves (JT2, E21, E22, E23). The cooling device is configured to cool the second refrigerant in the second refrigerant circuit (R2) with a liquid phase of the first refrigerant in the first refrigerant circuit (R1).

Description

Title of the invention: Hydrogen liquefaction process and installation

Technical area

This disclosure relates to the field of cryogenics, and more specifically that of the liquefaction of hydrogen.

Prior technique

[0002] In order to limit greenhouse gas emissions, hydrogen, preferably obtained by using non-carbon energy sources, is increasingly taken into consideration as an energy vector. However, to obtain an energy density which allows it to compete with hydrocarbons, in particular for transport applications, it is generally preferred to transport and store it in liquid form.

[0003] However, the liquefaction of hydrogen requires considerable energy consumption. Thus the specific energy consumption of the hydrogen liquefaction installations currently in service is approximately 12 to 15 kWh per kilogram of liquefied hydrogen. For example, the Linde ^® company, at its Leuna site, operates a liquefaction plant applying a Claude cycle to hydrogen, combined with pre-cooling exploiting the vaporization of liquid nitrogen, as described by Berstad, Stang and Neksà in “Comparison criteria for large-scale hydrogen liquefaction processes”, International Journal of Hydrogen Energy, vol. 34, no. 3, February 2009, pages 1560-1568. This installation has a specific energy consumption of 11.9 kWh per kilogram of liquefied hydrogen.

[0004] Several alternatives have been proposed to reduce the cost and energy consumption of hydrogen liquefaction. Thus, in “Large scale hydrogen liquefaction in combination with LNG re-gasification”, Proceedings of the 16th World Hydrogen Energy Conference 2006, p. 3326-3333, Kuendig, Lorhlein, Kramer and Huijsmans, proposed to replace, as a source of cold, the vaporization of liquid nitrogen by that of natural gas liquefied, thus achieving synergy with processes requiring natural gas in gaseous state. Other authors have proposed alternatives to the hydrogen Claude cycle. Thus, Matsuda and Nagami proposed, in “Study of large hydrogen liquefaction process” Hydrogen Energy, 1997, p. 175, to apply the Brayton cycle with helium, or even neon as refrigerant. The helium Brayton cycle was also proposed by Kuz'menko, Morkovkin and Gurov in "Concept of building medium-capacity hydrogen liquefiers with helium refrigeration cycle", Chemical and Petroleum Engineering, 2004, 40(1/2), p . 94-98. However, the helium Brayton cycle does not lend itself well to large-scale operation. For this reason, Valenti and Macchi have proposed, in “Proposal of an innovative, high-efficiency, large-scale hydrogen liquefier”, International Journal of Hydrogen Energy, 2008, 33(12), p. 3116-3121, a process applying four Joule-Brayton cycles in cascade. In practice, however, the energy efficiency of this process does not seem to be guaranteed.

[0005] Quack, in “Conceptual design of a high efficiency large capacity hydrogen liquefier”, AIP Conference Proceedings, 2002, 613, p. 255-263, proposed a process comprising an initial compression of hydrogen, followed by a pre-cooling with propane, a cooling applying a two-stage inverted Brayton cycle with "nelium" (mixture of helium and neon in proportion 4:1 molar), and expansion in a rotary gas expander. As part of the European IdealHY project, a hydrogen liquefaction process has been designed including pre-cooling with MR (acronym for “Mixed Refrigerant”, i.e. “mixed refrigerant”, designating a mixture comprising nitrogen and hydrocarbons), followed by "nelium" cooling and expansion liquefaction, while Krasae-in described, in "Optimal operation of a large-scale liquid hydrogen plant utilizing mixed fluid refrigeration System”, International Journal of Hydrogen Energy, 2014, 39(13), p. 7015-7029, a hydrogen liquefaction process comprising pre-cooling with MR and cooling applying a cascade of Joule-Brayton cycles to hydrogen, and theoretically allowing to obtain a specific energy consumption of only 5.35 kWh per kilogram of liquefied hydrogen for large-scale production of 100 metric tons per day.

[0006] European patent application specification EP 1 580506 A1 discloses a process and installation for liquefying hydrogen with a pre-cooling step using liquefied natural gas and a cooling step using a low-temperature compressed refrigerant. in compressors also cooled by liquefied natural gas, while Howe, Skinner and Finn disclosed, in "Advanced precooling for optimized hydrogen liquefaction", H2Tech, March 2021, other hydrogen liquefaction processes and installation with a step pre-cooling by a first refrigerant and a step of cooling by a second refrigerant. Finally, other hydrogen liquefaction processes and installations have been disclosed in Japanese patent application publications JP 2004-210597 A and JP S61 -140777. Disclosure of Invention

A first aspect of the present disclosure relates to a process for liquefying hydrogen offering lower specific energy consumption thanks to greater efficiency of a refrigerant compression step, and this with an adjustable flow rate of liquid hydrogen. [0008] For this, in the method according to this first aspect, which comprises a pre-cooling step, in which a hydrogen supply flow is cooled by a first refrigerant, a cooling step, in which the flow of hydrogen feed is cooled by a second cooler, and a step of expanding the hydrogen feed flow, each of the first and second coolers is successively subjected to at least one compression and at least one expansion in order to cool it, and a liquid phase of the first refrigerant cools the second refrigerant between at least three stages of a compression of the second refrigerant so that the second refrigerant does not exceed a temperature of 150 K, preferably 113 K, during said compression of the second refrigerant.

[0009] The expansion of the hydrogen feed rate can in particular be a substantially adiabatic expansion. By “substantially adiabatic” we mean, in the context of the present disclosure, an expansion in which the enthalpy does not vary substantially, for example does not vary more than 5%, or even 1%, insofar as this can be obtained by conventional means such as, in particular, Joule-Thomson effect valves, thermally insulated expansion valves.

[0010] Thanks to the division of the compression of the second refrigerant between at least three successive stages and to the use of the first refrigerant to cool the second refrigerant between at least three stages of this compression, it is thus possible to maintain the temperature of the second cooler below the threshold of 150 K, or even 113 K, thereby achieving a high degree of energy efficiency in the step of cooling the hydrogen feed flow by the second cooler.

[0011] The first refrigerant may in particular comprise nitrogen and/or argon. Thanks to the choice of nitrogen and/or argon as the first refrigerant, it is therefore possible to carry out said compression of the second refrigerant at a particularly low temperature, which makes it possible to increase the energy efficiency of the cycle of the second refrigerant.

The liquid phase of the first refrigerant can cool the second refrigerant upstream of each of said at least three stages of the compression of the second refrigerant, so that the initial temperature of the second refrigerant in each of said at least three stages is substantially identical, thus facilitating the use of common elements for said at least three compression stages.

[0013] The second refrigerant may comprise mainly, or even solely, hydrogen. Alternatively or in addition to hydrogen, the second refrigerant may nevertheless include neon and/or helium, in order to increase its density and therefore possibly allow it to be compressed in fewer stages.

[0014] In order to allow gradual cooling of the hydrogen feed rate over a wide temperature range, the second refrigerant can be divided into a first stream which is subjected to expansion to cool it and a second stream which is cooled by the first flow of the second refrigerant after the expansion of the first flow of the second refrigerant. The second flow of the second coolant can be subjected to expansion, in particular to substantially adiabatic expansion, after having been cooled by the first flow of the second coolant. [0015] In a similar manner and for the same reasons, the first refrigerant can also be divided into a first flow which is subjected to an expansion to cool it and a second flow which is cooled by the first flow of the first refrigerant after the expansion of the first flow of the first refrigerant. The first flow of the second coolant can also be subjected to expansion, in particular to substantially adiabatic expansion, after having been cooled by the first flow of the second coolant.

[0016] In order to improve the efficiency of the pre-cooling, the hydrogen supply flow can also be cooled by a third refrigerant during the pre-cooling stage. [0017] A second aspect of the present disclosure relates to a hydrogen liquefaction installation, which may be able to carry out the method of the first aspect and comprising for this purpose at least one hydrogen supply circuit, a first refrigerant, in particular in closed loop, containing a first refrigerant, a second refrigerant circuit, in particular in closed loop, containing a second refrigerant, a first set of heat exchangers traversed by the hydrogen supply circuit and by the first refrigerant circuit, a second set of heat exchangers traversed by the second refrigerant circuit and by the hydrogen supply circuit downstream of the first set of heat exchangers, and an expansion valve traversed by the supply circuit in hydrogen downstream of the second set of heat exchangers. In the present context, the term "expander" means any device capable of effecting an expansion of a fluid, whether with extraction of work, such as for example a turbine, or in a substantially adiabatic manner, such as for example an expansion valve. adiabatic. The terms “upstream” and “downstream” must be understood according to a normal direction of circulation of the fluid in each circuit. In order to achieve a high degree of energy efficiency in cooling a hydrogen feed stream, the first refrigerant circuit may include one or more compressors and one or more expanders, and the second refrigerant circuit may comprise at least three compressors and a cooling device arranged together so as to perform at least three compressions of the second refrigerant without exceeding a temperature of 150 K, preferably 113 K, and one or more expansion valves. The cooling device can be configured to cool the second refrigerant in the second refrigerant circuit with a liquid phase of the first refrigerant in the first refrigerant circuit, in particular in a vessel of the first refrigerant circuit. In particular, the second refrigerant circuit comprises several intermediate exchangers inserted between said at least three compressors of the second refrigerant circuit, and optionally arranged in the tank of the first refrigerant circuit, to maintain the temperature of the second refrigerant. In order to obtain a substantially identical intake temperature for each of said at least three compressors of the second refrigerant circuit, and thus facilitate the use of substantially identical elements for each of said at least three compressors of the second refrigerant circuit, one of said intermediate exchangers can be arranged upstream of each of said at least three compressors of the second refrigerant circuit.

[0019] Lubricant is normally present in the bearings of volumetric compressors typically used in hydrogen liquefaction installations and can escape into the flow of refrigerant. However, at the cryogenic temperatures at which the compressors of the second refrigerant circuit operate, these lubricant leaks could have deleterious effects in this second refrigerant circuit, and require a device for extracting this lubricant. In order to avoid this, said compressors of the second refrigerant circuit can be with magnetic bearings, in particular with active magnetic bearings. Also, to reduce wear, frequently associated with positive displacement compressors, they can be centrifugal compressors. They can also be electrically driven so as to be compatible with their total or partial immersion in the liquid phase of the first cooler at cryogenic temperature.

[0020] In order to ensure the isomeric stability, downstream of each heat exchanger, of the hydrogen of the feed flow, at least one heat exchanger of the first set or of the second set can be a catalytic exchanger, exposing the feed rate to a catalyst such as, for example, trivalent iron oxide, to effect an ortho-para catalytic conversion therein.

To maintain the temperature of the first refrigerant during its compression, and thus ensure a substantially isothermal compression, the compressors of the first refrigerant circuit can be cooled by water. However, air cooling is also possible for the compressors of the first circuit.

[0022] In order to ensure gradual and energy-efficient cooling, the second refrigerant circuit may comprise a branch, downstream of said compressors of the second refrigerant circuit, with a first branch comprising one or more of said expanders of the second refrigerant circuit in upstream of at least one of the heat exchangers of the second set downstream, and a second branch passing through at least one of the heat exchangers of the second set upstream of a confluence with the first branch of the second refrigerant circuit upstream of said compressors of the second refrigerant circuit.

In order to ensure gradual and energy-efficient pre-cooling, the first refrigerant circuit may comprise, analogously to the second refrigerant circuit, a branch, downstream of the compressors of the first refrigerant circuit, with a first branch comprising at least one of said expanders of the first refrigerant circuit upstream of at least one of the heat exchangers of the first set of heat exchangers, and a second branch passing through at least one of the heat exchangers of the first set of heat exchangers heat upstream of a confluence with the first leg of the first refrigerant circuit upstream of the compressors of the first refrigerant circuit. The installation may further comprise a third refrigerant circuit containing a third refrigerant and also passing through one or more heat exchangers of the first set of heat exchangers.

Brief description of the drawings

The description refers to the accompanying drawings in which:

[0026] [Fig. 1] Figure 1 is a schematic illustration of a hydrogen liquefaction installation according to a first embodiment.

[0027] [Fig. 2] Figure 2 is a schematic illustration of a hydrogen liquefaction installation according to a variant of the first embodiment.

[0028] [Fig. 3] Figure 3 is a schematic illustration of a hydrogen liquefaction installation according to a second embodiment.

Description of embodiments

The invention will be well understood and its advantages will appear better, on reading the following detailed description of embodiments shown by way of non-limiting examples. The temperature and pressure values given, by way of example, in this detailed description are absolute values.

[0030] Figure 1 illustrates a hydrogen liquefaction installation according to a specific embodiment. As illustrated, this installation may comprise a hydrogen supply circuit H, a first refrigerant circuit R1 and a second refrigerant circuit R2.

From an admission I, the hydrogen supply circuit H can pass successively through a first set of heat exchangers HX11, HX12, HX13 also crossed by the first refrigerant circuit R1, and a second set of heat exchangers HX21, HX22, HX23, HX24, HX25, HX26, also traversed by the second refrigerant circuit R2, before ending in a JTH expansion valve, for example in the form of an adiabatic expansion valve, opening into a TH phase separator with O liquid hydrogen outlet. It may also comprise a compressor of reinjection and/or ejector EJ, arranged at least upstream of the last heat exchanger HX26, and connected to the top of the phase separator TH through a recirculation pipe H1 to recover gaseous hydrogen from the phase separator TH and reinject it in the hydrogen supply circuit H upstream of the last heat exchanger HX26. Each of the heat exchangers can be a catalytic exchanger comprising a catalyst, such as for example trivalent iron oxide, to perform an ortho-para conversion in a flow of hydrogen circulating in the hydrogen supply circuit H.

The first refrigerant circuit R1 may be a closed-loop refrigerant circuit, containing a refrigerant such as, for example, nitrogen and/or argon, and possibly comprising a plurality of compressors C1 in series , a first regulator JT 1 , for example in the form of an adiabatic expansion valve, a tank T1 , and a second regulator E1 , for example in the form of a turbine, which can be centripetal or axial.

As illustrated, this first refrigerant circuit R1 may comprise, downstream of the compressors C1 and more precisely downstream of the first heat exchanger HX11 of the first set of heat exchangers, a branch S1 dividing the first refrigerant circuit FM into two branches FM 1 and FM 2. The second expansion valve E1 can be arranged on the first branch FM 1 of the first refrigerant circuit FM downstream of the branch S1. Downstream of the second expansion valve E1, the first branch FM 1 of the first refrigerant circuit FM can pass through the second heat exchanger HX12 of the first set of heat exchangers.

From the branch S1, the second branch R12 can pass through the second heat exchanger HX12 of the first set of heat exchangers. The first regulator JT 1 and the tank T 1 can be arranged on this second branch R12 downstream of the second heat exchanger HX12 of the first set of heat exchangers, and the third and second heat exchangers HX13, HX12 of the first set of The heat exchangers can be traversed by this second branch R12 of the first refrigerant circuit R1 in reverse order downstream of a gas outlet from this tank T 1 which then joins the first branch R11. The outlet of tank T 1 could however alternatively be a liquid outlet. Downstream of the confluence of the two branches R11 and R12, the first refrigerant circuit R1 can still pass through the first heat exchanger HX11 of the first set of heat exchangers before returning to the compressors C1. C1 compressors can be water-cooled compressors. It is for example possible for this to insert intermediate heat exchangers (not shown) between the compressors CM.

The first FM refrigerant circuit may also comprise at least one contaminant absorber, such as water or oxygen, in the liquid phase of the first refrigerant. This absorber can in particular take the form of a bed of powder to absorb the chemical species circulating in this first circuit of refrigerant FM and whose liquefaction temperature is higher than the temperature of the liquid phase in the tank T1, and be regenerable, for example by heating it. Thus, this absorber can make it possible to avoid the downstream propagation of pollutants which could, by solidifying, come to block the first circuit of refrigerant FM, in particular at the level of the heat exchangers HX11, HX12, HX13 of the first set of heat exchangers , or damage the JT1 , E1 regulators and/or the C1 compressors.

The second refrigerant circuit R2 can be a closed-loop refrigerant circuit, containing a refrigerant such as, for example, hydrogen. This second refrigerant circuit R2 may comprise a plurality of compressors C21, C22, C23, C24, a plurality of intermediate heat exchangers IC, a first expander JT2, for example in the form of an adiabatic expansion valve JT2, other expanders E21, E22 and E23, for example in the form of turbines, and two additional compressors C20a, C20b, each of which may comprise several stages.

[0038] The intermediate heat exchangers IC can be, as illustrated, arranged directly upstream and downstream of each of the compressors C21, C22, C23, C24 in the second refrigerant circuit R2, and partially or totally immersed in a liquid phase. of the first refrigerant in the tank T1, so as to allow compression of the second refrigerant at a cryogenic temperature, for example without exceeding 150 K, preferably 113 K, in any of these compressors C21, C22, C23 and C24. An intermediate heat exchanger IC being arranged upstream of each of the compressors C21, C22, C23, and C24, the respective inlet temperatures of each of these compressors C21, C22, C23 and C24 may be substantially identical. Downstream of the compressors C21, C22, C23 and C24 and of the intermediate heat exchangers IC, the second refrigerant circuit R2 can pass through the first heat exchanger HX21 of the second set of heat exchangers. In the second refrigerant circuit R2, a branch S2 dividing the second refrigerant circuit into a first branch R21 and a second branch R22 can be arranged downstream of the first heat exchanger HX21 of the second set of heat exchangers. The E21 expander can be arranged, downstream of the branch S2, on the first branch R21 of the second refrigerant circuit R2, which can then pass through the third heat exchanger HX23 of the second set of heat exchangers, in downstream of which the regulators E22 and E23 can be arranged successively. The first branch R21 can then pass through the heat exchangers HX24, HX23, HX22 and HX21 in reverse order.

[0040] Downstream of the branch S2, the second branch R22 of the second refrigerant circuit R2 can pass successively through the heat exchangers HX22, HX23, HX24, HX25 of the second set of heat exchangers. The JT2 expander can be arranged on the second branch R22 of the second refrigerant circuit, downstream of these heat exchangers and upstream of the last heat exchanger HX26 of the second set of heat exchangers, that the second branch R22 of the second circuit of refrigerant R2 passes through before passing through the heat exchangers HX25, HX24, HX23, HX22 and HX21 of the second set of heat exchangers in reverse order. The additional compressors C20a, C20b can be arranged at the end of the second branch R22 of the second refrigerant circuit R2 to allow the flow of refrigerant from this second branch R22 of the second refrigerant circuit R2 to join downstream that of the first branch R21 of the second refrigerant circuit R2 at a confluence upstream of compressors C21, C22, C23 and C24 and intermediate heat exchangers IC.

[0041] A heat shield (not shown), for example cooled with liquid nitrogen, can surround at least part of the second refrigerant circuit R2 and of the second set of heat exchangers HX21, HX22, HX23, HX24, HX25, HX26 in order to limit the thermal load. The second branch R22 of the second refrigerant circuit R2 may also include a buffer tank (not shown) downstream of the expander JT2 in order to absorb variations in speed.

In operation, this installation can implement a hydrogen liquefaction process in which a gaseous hydrogen supply flow introduced by the hydrogen supply circuit H at a pressure of, for example, 2, 1 MPa, and a temperature of, for example, 298 K, can be first cooled down to a temperature of, for example, 85 K, by the heat exchangers HX11 and HX12 of the first set of heat exchangers, then cooled further to a temperature of, for example, 82 K, by the last heat exchanger HX13 of the first set of heat exchangers. In addition, in order to ensure the isomeric stability of hydrogen at this temperature and to avoid its subsequent heating, this HX13 heat exchanger can operate, as a catalytic exchanger, an ortho-para catalytic conversion of the feed rate for y increase the rate of para-hydrogen, for example from 25 to 48%.

The flow of hydrogen to be liquefied then successively passes through the heat exchangers HX21, HX22, HX23, HX24 and HX25, where it is gradually cooled to a temperature of, for example, 26 K, and sees its rate of para-hydrogen gradually increase to, for example, 98% downstream of the HX25 heat exchanger. For this, it can go, for example, from a para-hydrogen rate of 48% upstream of the HX21 heat exchanger to a rate of 58% downstream of this HX21 heat exchanger, then to a rate of 67% in downstream of the HX22 heat exchanger, 77.5% downstream of the HX23 heat exchanger, and 96% downstream of the HX24 heat exchanger.

In the last heat exchanger HX26, the flow of hydrogen to be liquefied circulating through the supply circuit H can be further cooled, and its rate of para-hydrogen increased further up to, for example, 99%. Finally, its expansion, which can be substantially adiabatic, from a pressure of, for example, 2 MPa, upstream of the JTH expander to an outlet pressure of, for example, 0.2 MPa, makes it possible to further reduce its temperature. up to a temperature of, for example, 22.81 K. Downstream of the JTH expander, the flow of hydrogen circulating towards the tank TH can thus be liquid, for example, up to 98%. The remaining gaseous phase can be extracted from the top of the liquid hydrogen tank TH via line H1, and reinjected upstream of the last heat exchanger HX26 via ejector EJ.

[0045] In the first refrigerant circuit R1, the first refrigerant, which may in particular comprise nitrogen, can be compressed by the compressors C1, with a flow rate of, for example, 11.96 kg/s, from a pressure of, for example, 0.11 MPa, at a pressure of, for example, 5 MPa, and this in a substantially isothermal manner at a temperature of, for example, 285 K. Then, this first refrigerant can be cooled down to a temperature of, for example, 200 K, in the first heat exchanger HX11 of the first set of heat exchangers. At branch S1, downstream of this first heat exchanger HX11, the first refrigerant can be divided into two streams.

[0046] A first flow of the first refrigerant, which can comprise for example 70% of the total flow of the first refrigerant, can be directed through the first branch R11 of the first refrigerant circuit FM towards the expansion valve E1, where it can be expanded up to 'at a pressure of, for example, 0.12 MPa, so as to reduce its temperature to a temperature of, for example, 84 K, to then pass through the second heat exchanger HX12 of the first set of heat exchangers by absorbing heat.

A second flow of the first refrigerant, which may include the remainder of the flow of the first refrigerant, may be directed, through the second branch R12 of the first refrigerant circuit, to the second heat exchanger HX12 of the first set of exchangers of heat, to be cooled there to a temperature of, for example, 85 K, to then be expanded, in particular in a substantially adiabatic manner, at the expander JT1, and thus to liquefy it at least partially by reducing its temperature there to at, say, 80K. Downstream of the JT1 expander, this second flow of the first refrigerant, at least partially liquid, can be received in the tank T1, downstream of which it can still cross, in reverse order, the third and second heat exchangers HX13, HX12 of the first set of heat exchangers to be reheated there before joining the first flow of the first refrigerant. Downstream of this confluence of the two flows of the first refrigerant, the first refrigerant can still pass through the first heat exchanger HX11 of the first set of heat exchangers to be reheated there before returning to the compressors C1 of the first refrigerant circuit.

In the second refrigerant circuit R2, the second refrigerant, which can in particular be hydrogen, can be compressed by the compressors C21, C22, C23, and C24 with a flow rate of, for example, 0.666 kg/s , from a pressure of, for example, 0.45 MPa, to a pressure of, for example, 2.94 MPa, and this without exceeding a maximum temperature of, for example, 100 K, thanks to the passage of the second refrigerant through the intermediate exchangers IC upstream and downstream of each of the compressors C21, C22, C23 and C24. Each of the compressors C21, C22, C23 and C24 can be driven with a power of, for example, 140 kW. The respective speeds of compressors C21, C22,

C23 and C24 may rise in the direction of the flow of the second refrigerant. Thus, the compressor C21 can rotate at a first speed of, for example, 80,000 revolutions per minute, the compressor C22 can rotate at a second speed of, for example, 90,000 revolutions per minute, higher than the first speed, the compressor C23 can rotate at a third speed of, for example, 115,000 rpm, higher than the second speed, and the compressor C24 can rotate at a fourth speed of, for example, 125,000 rpm, higher than the third speed. After having been cooled to an initial temperature of, for example, 82 K, in the first intermediate exchanger IC, the first refrigerant can thus be compressed to pressures of, for example, 0.72 MPa, 1.16 MPa, 1.84 MPa and 2.96 MPa respectively downstream of compressors C21, C22, C23 and C24, reaching a temperature of, for example, 100 K downstream of each of these compressors C21, C22, C23 and C24, for then be cooled down to substantially the same initial temperature in each subsequent intermediate exchanger IC, with a pressure drop of, for example, 0.02 MPa in each intermediate exchanger IC.

Then, this first refrigerant can be cooled down to a temperature of, for example, 69 K, in the first heat exchanger HX21 of the second set of heat exchangers. The first refrigerant can then be split into two streams at branch S2. [0050] A first flow of the second refrigerant, which can comprise for example 88% of the total flow of the second refrigerant, can then be directed through the first branch R21 of the second refrigerant circuit R2 towards the expansion valve E21, where it can be expanded. to a pressure of, for example, 1.9 MPa, so as to reduce its temperature to a temperature of, for example, 60 K, to then pass through the third heat exchanger HX23 of the second set of heat exchangers. heat and be cooled there to, for example, 51 K, before being further gradually expanded to a pressure of, for example,

0.5 MPa, to expanders E22 and E23, so as to further reduce its temperature down to, for example, 31.5 K. It can then still pass through the fourth, third, second and first heat exchangers HX24, HX23, HX22 and HX21 in reverse order to absorb heat therein until reaching a temperature of, for example, 80 K at a pressure of, for example, 0.45 MPa.

A second flow of the second refrigerant, which may comprise the remainder of the flow of the second refrigerant, may be directed, through the second branch R22 of the second refrigerant circuit R2, to the second, third, fourth and fifth heat exchangers HX22, HX23, HX24, HX25 of the second set of heat exchangers, there to be successively cooled down to a temperature of, for example, 26 K, to then be expanded, in particular substantially adiabatically, down to a pressure of, for example, 0.17 MPa, at the JT2 expander, and thus reduce its temperature there to, for example, 22 K. Downstream of the JT2 expander, this second flow of the second refrigerant can still cross in reverse order the sixth, fifth, fourth, third, second and first heat exchangers HX26, HX25, HX24, HX23, HX22 and HX21 of the first set of heat exchangers to absorb heat therein until reaching a temperature of, for example, 80K at a pressure of, for example, 0.15 MPa. To allow it to join the first flow of the second refrigerant at the confluence of the two branches R21, R22 of the second circuit R2, before returning to the compressors C21, C22, C23, C24 and the intermediate exchangers IC, the second flow can still be compressed to the same pressure as the first flow in the additional compressors C20a, C20b. the additional compressor C20a can be a two-stage compressor, driven with a power of, for example, 25 kW, at a speed of, for example, 100,000 revolutions per minute, to compress this second flow to a pressure of, for example , 0.3 MPa and a temperature of, for example, 113 K, while the additional compressor C20b can also be a two-stage compressor, driven with a power of, for example, 25 kW, at a speed of, for example , 100,000 revolutions per minute, to compress this second flow to a pressure of, for example, 0.45 MPa and a temperature of, for example, 131.5 K.

Thus, the refrigeration cycle applied in the second refrigerant circuit R2 is a Claude cycle at two pressures. Although, for this first embodiment, it has been proposed to use hydrogen as the second refrigerant, it is also possible to use other refrigerants, such as helium, or even a mixture of hydrogen and neon. . In this alternative embodiment, in order to avoid the blocking of the second refrigerant circuit by solid neon, it would be preferable to separate the neon from the second refrigerant before its temperature drops below 25 K. For this, it is in particular conceivable to use the condensation of neon and its separation in the liquid phase. Similarly, it is also possible to use other substances alternatively or in addition to nitrogen as the first refrigerant, such as argon, for example. All pressures mentioned by way of example in this description must be understood as absolute pressures.

[0053] Figure 2 schematically illustrates a hydrogen liquefaction installation according to a variant of the first embodiment, in which the last heat exchanger HX13 of the first set of heat exchangers can be integrated into the tank T 1 of the first refrigerant circuit R1, so as to be partially or totally immersed therein in the liquid phase of the first refrigerant. The remaining elements of the installation illustrated in FIG. 2 are identical or equivalent to those of the installation of FIG. 1 and therefore receive the same references therein. Its operation is also analogous. Figure 3 schematically illustrates a hydrogen liquefaction installation according to a second embodiment, which may include a third refrigerant circuit R3. This third refrigerant circuit R3 can be a closed loop refrigerant circuit, containing a third refrigerant. This third refrigerant can be a mixed refrigerant, and in particular a mixed refrigerant comprising hydrocarbons. Such a mixed refrigerant can be formed by a mixture of nitrogen, methane, ethane, propane and butane.

The third refrigerant circuit R3 may comprise a set of compressors C3 upstream of a first phase separator T31, which may form a first branch of the third refrigerant circuit R3, dividing it into a first branch R31, which may comprise an additional compressor C3', and a second branch R32, which may include a pump P3. These two branches R31, R32 can join downstream of the compressor C3 'and the pump P3, upstream of a second phase separator T32, which can form a second branch of the third refrigerant circuit R3, dividing it into a third branch R33 and a fourth branch R34.

The third branch R33 may comprise a JT33 regulator, for example in the form of an adiabatic expansion valve, and cross, both upstream and downstream of this JT33 regulator, a first heat exchanger HX10 of the first set heat exchangers, which may include four heat exchangers HX10, HX11, HX12 and HX13 in this second embodiment, to then return upstream of the set of compressors C3.

The fourth branch R34 can also pass through the first heat exchanger HX10 of the first set of heat exchangers, upstream of a third phase separator T33, which can form a third branch of the third refrigerant circuit R3, dividing the fourth branch R34 into a fifth branch R35 and a sixth branch R36.

The fifth branch R35 may comprise a JT35 expander, for example in the form of an adiabatic expansion valve, and cross, both upstream and downstream of this JT35 expander, the second heat exchanger HX11 of the first set of heat exchangers. The sixth branch R36 may also include a JT36 regulator, for example in the form of an adiabatic expansion valve, and pass successively, upstream of this regulator, the second and third heat exchangers HX11, HX12 of the first set of heat exchangers, to cross them again, in reverse order, downstream of the JT36 expander, before joining the fifth branch R35.

The first heat exchanger HX10 of the first set of heat exchangers can still be crossed by the fourth branch R34 downstream of the confluence of the fifth and sixth branches R35, R36, upstream of a confluence of the fourth branch R34 with the third branch R33 upstream of the return to compressors C3.

[0061] Compared to that of the first embodiment, the first refrigerant circuit R1 can be simplified, and form only a single loop passing through, downstream of the compressors C1, the first to third heat exchangers HX10, HX11, HX12 in a first direction, to then cross them in reverse order downstream of a single regulator JT 1 , which can be in the form of an adiabatic expansion valve, and of the tank T 1 , before returning to the inlet C1 compressors. As in the variant of the first embodiment, a last heat exchanger HX13 of the first set of heat exchangers HX10, HX11, HX12, HX13 through which the hydrogen supply circuit H passes can be integrated into the tank T1 to be partially or totally immersed in the liquid phase of the first refrigerant.

The remaining elements of the installation according to this second embodiment may be identical or equivalent to those of the first embodiment and consequently receive the same marks.

In operation, in the third refrigerant circuit R3, the third refrigerant can first be compressed, in the compressors C3, for example from 0.1 MPa to 1.1 MPa. At this pressure, a liquid phase can appear, which can be separated from the gaseous phase of the third refrigerant in the first phase separator T31 of the third refrigerant circuit R3, to be diverted to the second branch R32 of the third refrigerant circuit R3 and be pumped there by the pump P3 up to a pressure of, for example, 2.2 MPa, while that the gaseous phase can be directed through the first branch R31, to be compressed there by the additional compressor C3' up to the same pressure as the liquid phase of the second branch R32. The separation of the phases and the pumping of the liquid phase by a pump, for the last increase in pressure, makes it possible to limit the energy consumption for this stage.

[0064] Downstream of the confluence of the first and second branches R31, R32 of the third refrigerant circuit R3, the gaseous and liquid phases can be separated again in the second phase separator T32, to direct the liquid phase through the third branch R33 and the gaseous phase through the fourth branch R34.

The liquid fraction of the third refrigerant directed through the third branch R33 of the third refrigerant circuit R3 can first be cooled down to a temperature of, for example, 182 K, in the first heat exchanger HX10 of the first set of heat exchangers, to then be expanded, in particular in a substantially adiabatic manner, up to a pressure of, for example, 0.1 MPa, in the JT33 expansion valve of the third branch R33, before crossing the first heat exchanger HX10 of the first set of heat exchangers to absorb heat therein, and then be returned to the compressors C3.

The gaseous fraction of the third refrigerant directed through the fourth branch R34 of the third refrigerant circuit R3 can first also be cooled down to a temperature of, for example, 182 K, in the first heat exchanger HX10 of the first set of heat exchangers to partially condense there before arriving at the third phase separator T33, in which liquid and solid phases can again be separated to be directed, respectively, through the fifth and sixth branches R35 , R36 of the third refrigerant circuit.

The liquid fraction of the third refrigerant directed through the fifth branch R35 of the third refrigerant circuit R3 can be cooled down to a temperature of, for example, 115 K in the second exchanger HX11 of the first set of heat exchangers. , to then be relaxed, in particular in a substantially adiabatic manner, up to a pressure of, for example, 0.1 MPa, in the JT35 regulator of the fifth branch R35, before crossing again, in reverse order, the second and first heat exchangers HX11, HX10 from the first set of heat exchangers to absorb heat there, and then be sent back to the C3 compressors.

The gaseous fraction of the third refrigerant directed through the sixth branch R36 of the third refrigerant circuit R3 can be cooled down to a temperature of, for example, 82 K by crossing the second and third heat exchangers HX11, HX12 of the first set of heat exchangers, to then be expanded, in particular substantially adiabatically, up to a pressure of, for example, 0.1 MPa, in the JT36 expander of the sixth branch R36, before crossing again , in reverse order, the third, second and first heat exchangers HX12, HX11, HX10 of the first set of heat exchangers to absorb heat therein, and then be returned to the compressors C3.

In the first refrigerant circuit R1, the first refrigerant can be compressed, for example from 0.1 MPa to 4 MPa, in the compressors C1, and then cooled down to, for example, 90 K, crossing the first, second and third heat exchangers HX10, HX11, HX12 of the first set of heat exchangers. It can then be expanded, in particular substantially adiabatically, in the single expander JT 1 of the first refrigerant circuit R1, so as to reduce its temperature to, for example, 78 K and liquefy it at least in part. before arriving in tank T 1.

A gaseous fraction of the first refrigerant can leave the tank T1 to cross, in reverse order, the third, second and first heat exchangers HX12, HX11, HX10 of the first set of heat exchangers to absorb heat therein. before returning to the C1 compressors of the first refrigerant circuit.

In the second refrigerant circuit R2, the second refrigerant can circulate in a manner substantially analogous to the first embodiment, while the gaseous hydrogen introduced into the hydrogen supply circuit H can first be cooled down to at, for example, 90 K, crossing the first, second and third heat exchangers HX10, HX11 and HX12 of the first set of heat exchangers, to then be cooled down to 80 K by passing through the last heat exchanger HX13 of the first set of heat exchangers which, as in the first embodiment, may be a catalytic exchanger capable of operating, as a catalytic exchanger, an ortho-para catalytic conversion of the feed flow to increase the para-hydrogen level therein, for example from 25 to 48 %. The subsequent steps of the cooling and liquefaction of the hydrogen circulating through the hydrogen supply circuit H can be analogous to those of the first embodiment.

Although the present invention has been described with reference to specific embodiments, it is obvious that various modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. Further, individual features of the various embodiments discussed may be combined in additional embodiments. Accordingly, the description and the drawings should be considered in an illustrative rather than restrictive sense.

Claims

[Claim 1] Process for liquefying hydrogen, comprising at least: a pre-cooling step, in which a hydrogen feed flow is cooled by a first cooler, a cooling step, in which the hydrogen feed is cooled by a second cooler, and a step of expansion, in particular substantially adiabatic expansion, of the hydrogen feed flow, and in which each of the first and second coolers is successively subjected to at least one compression and to at least one expansion in order to cool it, and a liquid phase of the first refrigerant cools the second refrigerant between at least three stages of a compression of the second refrigerant so that the second refrigerant does not exceed a temperature of 150 K, preferably 113 K , during said compression of the second refrigerant.

[Claim 2] A process for liquefying hydrogen according to claim 1, wherein the first coolant comprises nitrogen and/or argon.

[Claim 3] A process for liquefying hydrogen according to any one of claims 1 or 2, wherein the liquid phase of the first refrigerant cools the second refrigerant upstream of each of said at least three stages of compression of the second refrigerant.

[Claim 4] A method of liquefying hydrogen according to any one of claims 1 to 3, wherein the second refrigerant comprises hydrogen, neon and/or helium.

[Claim 5] A process for liquefying hydrogen according to any one of claims 1 to 4, wherein the second refrigerant is divided into a first stream which is subjected to expansion to cool it and a second stream which is cooled by the first flow of the second refrigerant after the expansion of the first flow of the second refrigerant.

[Claim 6] A process for liquefying hydrogen according to Claim 5, in which the second flow of the second refrigerant is subjected to expansion, in particular substantially adiabatic expansion, after having been cooled by the first flow of the second refrigerant.

[Claim 7] A process for liquefying hydrogen according to any one of claims 1 to 6, wherein the first refrigerant is divided into a first stream which is subjected to expansion to cool it and a second stream which is cooled by the first flow of the first refrigerant after the expansion of the first flow of the first refrigerant.

[Claim 8] A process for liquefying hydrogen according to Claim 7, in which the second flow of the first coolant is subjected to expansion, in particular to substantially adiabatic expansion, after being cooled by the first flow of the first coolant.

[Claim 9] A method of liquefying hydrogen according to any one of claims 1 to 8, wherein the hydrogen feed stream is also cooled by a third cooler during the pre-cooling step.

[Claim 10] Hydrogen liquefaction installation comprising at least: a hydrogen supply circuit (H), a first coolant circuit (RI) containing a first coolant, a second coolant circuit (R2) containing a second refrigerant, a first set of heat exchangers (HX10, HX11, HX12, HX13) through which the hydrogen supply circuit (H) and the first refrigerant circuit (RI) pass, a second set of heat exchangers (HX21 , HX22, HX23, HX24, HX25, HX26) crossed by the second refrigerant circuit (R2) and by the hydrogen supply circuit (H) downstream of the first set of heat exchangers (HX10, HX11, HX12, HX13), and an expansion valve, for example an adiabatic expansion valve (JTH), crossed by the hydrogen supply circuit (H) downstream of the second set of heat exchangers (HX21, HX22, HX23, HX24, HX25 , HX26), in which the first refrigerant circuit (RI) comprises one or more compressors (Cl) and one or more expanders (E1, JT1), and the second refrigerant circuit (R2) comprises at least three compressors (C21, C22, C23, C24) and a cooling device comprising several intermediate exchangers (IC) interposed between the di ts at least three compressors (C21, C22, C23, C24) of the second refrigerant circuit (R2) so as to carry out at least three compressions of the second refrigerant without exceeding a temperature of 150 K, preferably 113 K, and one or more expansion valves (JT2, E21, E22, E23), the cooling device being configured to cool the second refrigerant in the second refrigerant circuit (R2) with a liquid phase of the first refrigerant in the first refrigerant circuit (RI), in particular in a tank (Tl) of the first refrigerant circuit (RI).

[Claim 11] Hydrogen liquefaction plant according to Claim 10, in which one of the said intermediate exchangers (IC) is arranged upstream of each of the said at least three compressors (C21, C22, C23, C24) of the second refrigerant circuit .

[Claim 12] Hydrogen liquefaction plant according to any one of Claims 10 or 11, in which the said at least three compressors (C21, C22, C23, C24) of the second refrigerant circuit (R2) have magnetic bearings , in particular with active magnetic bearings.

[Claim 13] Hydrogen liquefaction plant according to any one of Claims 10 to 12, in which the said at least three compressors (C21, C22, C23, C24) of the second refrigerant circuit (R2) are centrifugal compressors .

[Claim 14] Hydrogen liquefaction plant according to any one of Claims 10 to 13, in which at least one heat exchanger (HX13, HX21, HX22, HX23, HX24, HX25, HX26) of the first set of heat exchangers or the second set of heat exchangers is a catalytic exchanger.

[Claim 15] Hydrogen liquefaction plant according to any one of Claims 10 to 14, in which the second refrigerant circuit (R2) comprises a branch (S2), downstream of the said at least three compressors (C21, C22 , C23, C24) of the second refrigerant circuit (R2), with a first branch (R21) comprising one or more of said expansion valves (E21, E22, E23) of the second refrigerant circuit (R2) and crossing downstream at least one of heat exchangers (HX21, HX22, HX23, HX24) of the second set, and a second branch (R22) passing through at least one of the heat exchangers (HX21, HX22, HX23, HX24, HX25, HX26) of the second set before joining the first branch (R21) of the second refrigerant circuit (R2) upstream of said compressors (C21, C22, C23) of the second refrigerant circuit (R2).

[Claim 16] Hydrogen liquefaction plant according to any one of Claims 10 to 15, in which the first refrigerant circuit (RI) comprises a branch (SI), downstream of the compressors (Cl) of the first refrigerant circuit, with a first branch (RI 1) comprising at least one of said expansion valves (El) of the first refrigerant circuit (RI) and passing downstream through at least one of the heat exchangers (HX12) of the first set of heat exchangers (HX11, HX12, HX13), and a second branch (R12) passing through at least one of the heat exchangers (HX12, HX13) of the first set of heat exchangers (HX11, HX12, HX13) before to join the first branch (Rll) of the first refrigerant circuit (RI) upstream of the compressors (Cl) of the first refrigerant circuit (RI).

[Claim 17] Hydrogen liquefaction plant according to any one of Claims 10 to 16, further comprising a third refrigerant circuit (R3) containing a third refrigerant and also passing through one or more heat exchangers (HX10, HX11 , HX12) of the first set of heat exchangers (HX10, HX11, HX12, HX13).