Hydrogen liquefaction installation and process

Abstract

The invention relates to a hydrogen liquefaction plant and method comprising a hydrogen supply circuit (2) feeding a cryogenic storage tank (8) equipped with a withdrawal line (11) for supplying hydrogen to a reservoir (12), the plant (1) comprising a set of heat exchanger(s) (3, 4, 5) in heat exchange with the supply circuit (2) and with a cooling device comprising a cryogenic refrigerator (7) with a cycle refrigeration system for a cycle gas in a cycle circuit (70), the cycle gas comprising a mixture comprising at least 50% by mole of helium and less than 50% by mole of hydrogen, the cycle circuit (70) of the refrigerator (7) comprising a compression element (17) having at least one centrifugal compressor, a cooling element (3, 4), an expansion element (27, 37) and an expansion element (5, 4, 3) heating, the installation (1) comprising at least one pipe (9,10) vaporization gas recovery for recovering gaseous hydrogen, the vaporization gas recovery line (9, 10) being connected to the cycle circuit (70) to reinject this vaporization gas into the cycle circuit, the installation (1) further comprising a transfer line (13) connecting the cycle circuit (70) to the supply circuit (2) and configured to allow the transfer of cycle gas into the supply circuit (2). Abbreviated figure: Fig. 1,

Description

Title of the invention: Hydrogen liquefaction installation and method

[0001] The invention relates to an installation and a method for liquefying hydrogen.

[0002] The invention relates more particularly to a liquefaction installation of hydrogen comprising a hydrogen supply circuit having an upstream end intended to be connected to a source of gaseous hydrogen and a downstream end connected to at least one cryogenic storage of liquefied hydrogen of the installation, the cryogenic storage being equipped with a withdrawal line configured to allow the supply of liquefied hydrogen to at least one tank to be filled, for example a mobile tank, the installation comprising an assembly of heat exchanger(s) in thermal exchange with the supply circuit and a cooling device in thermal exchange with at least part of the assembly of heat exchanger(s) configured to cool the supply circuit, the cooling device comprising a cryogenic refrigerator with a cycle gas refrigeration system in a cycle circuit, the cycle gas comprising a mixture comprising at least 50% by mole of helium and less than 50% by mole of hydrogen,The refrigerator cycle circuit includes a cycle gas compression unit comprising at least one centrifugal compressor, a cycle gas cooling unit, a cycle gas expansion unit, and a cycle gas heating unit. The installation includes at least one vaporization gas recovery line configured to recover gaseous hydrogen, for example, generated during the supply of liquefied hydrogen to at least one tank to be filled. The vaporization gas recovery line is connected to the cycle circuit to reinject this vaporization gas into the cycle circuit.

[0003] For the liquefaction of hydrogen, it is known to use hydrogen cycle refrigerators. However, the low molar mass of hydrogen makes its compression by centrifugal compressors inefficient. A known solution consists of adding a heavier compound to the cycle circuit for compression; this heavier compound (neon or hydrocarbon) is separated before the final expansions of the refrigeration cycle. This complicates the installation.

[0004] Another known solution is to use a cycle gas comprising or consisting of helium. This requires a closed refrigeration cycle or poses problems with helium migration.

[0005] Furthermore, the recovery of hydrogen vaporization gas requires expensive or complex dedicated devices.

[0006] One object of the present invention is to overcome all or part of the disadvantages of the prior art noted above.

[0007] To this end, the installation according to the invention, which also conforms to the generic definition given in the preamble above, is essentially characterized in that the installation further comprises a transfer line connecting the cycle circuit to the supply circuit and configured to allow the transfer of cycle gas into the supply circuit.

[0008] Furthermore, embodiments of the invention may include one or more of the following features: - the installation includes a first vaporization gas recovery line connecting the cryogenic storage to the cycle circuit configured to transfer vaporization gas from the cryogenic storage to the cycle circuit, - the installation includes a second vaporization gas recovery line comprising a downstream end connected to the cryogenic storage and / or the cycle circuit and an upstream end configured to be connected to a tank to be filled and / or a tank filling circuit, the second recovery line being configured to transfer vaporization gas from a tank to be filled and / or a tank filling circuit to the cryogenic storage and / or the cycle circuit, - the cycle circuit includes, downstream of a pressure-reducing device, a phase separator pot, - at least one vaporization gas recovery line is connected to the phase separator pot, - the supply circuit includes a final expansion device located between the heat exchanger assembly(ies) and the cryogenic storage.

[0009] The invention also relates to a hydrogen liquefaction process using an installation according to any one of the preceding claims, the process comprising a step of recovering vaporization gas consisting mainly of hydrogen in the refrigerator cycle circuit, a step of transferring a determined quantity of cycle gas into the supply circuit and a step of recovering vaporization gas consisting mainly of helium from the cryogenic storage to the cycle circuit.

[0010] According to other possible features, the installation is configured to maintain a helium level in the cycle circuit above a determined threshold.

[0011] The invention may also relate to any alternative device or method comprising any combination of the above or below features within the scope of the claims.

[0012] Other features and advantages will become apparent from the following description, given with reference to the figures in which: Brief description of the figures

[0013] The invention will be better understood upon reading the following description, given solely by way of example and made with reference to the accompanying drawings in which:

[0014] [Fig. 1] is a schematic and partial view illustrating an example of the structure and operation of an installation according to the invention. Detailed description

[0015] In all figures, the same references refer to the same elements.

[0016] In this detailed description, the following are examples. The fact that the description refers to one or more embodiments does not mean that the features apply only to a single embodiment. Simple features from different embodiments can also be combined and / or interchanged to provide other embodiments.

[0017] The illustrated hydrogen liquefaction installation 1 conventionally comprises a hydrogen supply circuit 2 having an upstream end intended to be connected to a source of gaseous hydrogen (for example at ambient temperature and at a pressure between a few bar and 40 bar) and a downstream end connected to at least one cryogenic storage 8 of the liquefied hydrogen.

[0018] As schematically shown, the cryogenic storage 8 can be equipped with at least one withdrawal line 11 configured to allow the supply of liquefied hydrogen to at least one tank 12 to be filled, for example mobile tanks.

[0019] The installation 1 includes, for example in at least one cold box, a set of heat exchangers 3, 4, 5 in heat exchange with the supply circuit 2 and a cooling device in heat exchange with at least part of the set of heat exchangers 3, 4, 5 configured to cool the supply circuit 2 for the purpose of hydrogen liquefaction.

[0020] Downstream of the set of exchangers 3, 4, 5n the supply circuit may include a final expansion device 6 (turbine and / or valve for example).

[0021] The cooling device may include at least one pre-cooling system 14 (for example nitrogen cycle or other) configured to pre-cool the hydrogen from the supply circuit 2 to a pre-cooling temperature (for example 80K).

[0022] The cooling device includes a cryogenic refrigerator 7 configured to further cool the hydrogen for its liquefaction, for example to a temperature of 20K.

[0023] The refrigerator 7 is of the type with a cycle refrigeration gas in a cycle circuit 70.

[0024] The cycle gas comprises a mixture comprising at least 50% by mole of helium and less than 50% by mole of hydrogen, for example 80% helium and 20% hydrogen.

[0025] The mixture has a density at the compressor inlet compatible with a centrifugal compression technology.

[0026] Classically, the cycle circuit 70 of the refrigerator 7 includes a cycle gas compression element 17 comprising one or more centrifugal type compressors, a cycle gas cooling element 3, 4 (for example the one or more counter-current multi-pass heat exchangers), a cycle gas expansion element 27, 37 (one or more turbine and / or expansion valve(s)) and a cycle gas heating element 5, 4, 3 (for example the same counter-current heat exchangers).

[0027] As illustrated, the cycle circuit 70 may include, at its colder end, downstream of an expansion member 37, a phase separator pot 47. The phase separator pot 47 may form a thermosiphon supplying cooling power to at least one heat exchanger 5 via the cycle gas flow. A gas outlet from the separator pot 47 may return a gas flow to the compression member 17.

[0028] The illustrated installation 1 includes a first vaporization gas recovery line 10 connecting the cryogenic storage 8 to the cycle circuit 70, for example at the separator pot 47. This first recovery line 10 is configured to transfer vaporization gas from the cryogenic storage 8 to the cycle circuit 70.

[0029] As illustrated, the installation 1 includes, in this example, a second vaporization gas recovery line 9 configured to recover vaporization gases (hydrogen) collected in the tanks 12 to be filled and / or in the circuitry intended for filling these tanks 12 (loading bay for example).

[0030] This second recovery line 9 includes an upstream end configured to be connected to a tank 12 to be filled and / or a filling circuit for a tank 12 to be filled and a downstream end connected to the installation 1. In this example, the downstream end of the second recovery line 9 is connected to the separator pot 47 (via the first recovery line 10).

[0031] Of course, the downstream end of the second recovery line 9 could be connected directly to the separator pot 47 or to the cryogenic storage 8 or to another location in the cycle circuit 70.

[0032] This second recovery line 9 is configured to allow the recovery of vaporized hydrogen in tanks 12 to be filled and / or in the filling circuitry of the latter in the installation and in particular in the cycle circuit 70.

[0033] Installation 1 further includes a transfer line 13 connecting the cycle circuit 70 to the supply circuit 2 and configured to allow the transfer of cycle gas into the supply circuit 2. For example, the transfer line 13 draws the cycle gas after pre-cooling and is connected to the already pre-cooled supply circuit 2.

[0034] Thus, in operating configuration, the helium and hydrogen mixture of the cycle gas can be compressed in the centrifugal compressor(s) 17 offering better efficiency compared to a cycle gas consisting solely of hydrogen (due to the relatively higher molar mass of helium).

[0035] Vaporized hydrogen can be recovered from the tank 12 or the loading bay via the second recovery line 9. This gas, essentially composed of hydrogen, can be admitted into the cycle circuit 70 without requiring a separate dedicated recovery system (the same applies to the vaporization gas from the cryogenic storage 8).

[0036] Adding hydrogen to the cycle circuit 70 can eventually decrease the relative proportion of helium in the cycle circuit 70.

[0037] However, installation 1 allows the transfer of the cycle gas into the feed circuit 2 via the transfer line 13. This feed gas 2 therefore receives a fraction of helium. This feed gas, which contains helium, after a final expansion 6, can produce liquid hydrogen and, in particular, subcooled liquid hydrogen (liquid hydrogen at a temperature below its saturation temperature).

[0038] The cooled and at least partially liquefied fluid is poured into the cryogenic storage 8. The gaseous or vaporized portion in the storage contains proportionally more helium. This helium-rich vaporization gas can be supplied to the cycle circuit 70 via the first recovery line 10. This makes it possible to maintain a proportion of helium in the cycle gas above the minimum threshold, for example, 50%.

[0039] All or part of the pipes 13, 9, 10 or circuits may include one or more valves to control the circulation or flow rate of fluid. The assembly may be controlled by an electronic device comprising a microprocessor.

[0040] Compared to an installation using a refrigerator with a closed refrigeration cycle, the liquid hydrogen produced by the open-cycle installation according to the invention may contain a small proportion of residual helium. For example, 0.5% by mole in the liquid hydrogen produced at 20 K. However, this fraction of helium can be easily separated if necessary.

Claims

1.

2. Demands Hydrogen liquefaction installation comprising a hydrogen supply circuit (2) having an upstream end intended to be connected to a source of gaseous hydrogen and a downstream end connected to at least one cryogenic liquefied hydrogen storage (8) of the installation, the cryogenic storage (8) being equipped with a withdrawal line (11) configured to allow the supply of liquefied hydrogen to at least one tank (12) to be filled, for example a mobile tank, the installation (1) comprising an assembly of heat exchanger(s) (3, 4, 5) in heat exchange with the supply circuit (2) and a cooling device in heat exchange with at least part of the assembly of heat exchanger(s) (3, 4, 5) configured to cool the supply circuit (2), the cooling device comprising a cryogenic refrigerator (7) with a cycle refrigeration of a cycle gas in a cycle circuit (70),the cycle gas comprising a mixture comprising at least 50% by mole of helium and less than 50% by mole of hydrogen, the refrigerator (7) cycle circuit (70) comprising a cycle gas compression unit (17) having at least one centrifugal compressor, a cycle gas cooling unit (3, 4), a cycle gas expansion unit (27, 37) and a cycle gas heating unit (5, 4, 3), the installation (1) comprising at least one vaporization gas recovery line (9, 10) configured to recover gaseous hydrogen, for example, generated during the supply of liquefied hydrogen to at least one tank (12) to be filled, the vaporization gas recovery line (9, 10) being connected to the cycle circuit (70) to reinject this vaporization gas into the cycle circuit,the installation (1) further comprising a transfer line (13) connecting the cycle circuit (70) to the supply circuit (2) and configured to allow the transfer of cycle gas into the supply circuit (2). Installation according to claim 1, characterized in that it comprises a first vaporization gas recovery line (10) connecting the cryogenic storage (8) to the cycle circuit (70) configured to transfer vaporization gas from the cryogenic storage (8) to the cycle circuit (70).

3. Installation according to claim 1 or 2, characterized in that it comprises a second vaporization gas recovery line (9) including a downstream end connected to the cryogenic storage (8) and / or the cycle circuit (70) and an upstream end configured to be connected to a tank (12) to be filled and / or a tank (12) filling circuitry, the second recovery line (9) being configured to transfer vaporization gas from a tank (12) to be filled and / or a tank (12) filling circuitry to the cryogenic storage (8) and / or the cycle circuit (70).

4. Installation according to any one of the preceding claims, characterized in that the cycle circuit (70) comprises, downstream of a decompression member (37), a phase separator pot (47).

5. Installation according to claim 4, characterized in that at least one vaporization gas recovery line (9, 10) is connected to the phase separator pot (47).

6. Installation according to any one of the preceding claims, characterized in that the supply circuit (2) includes a final expansion device (6) located between the heat exchanger assembly (3, 4, 5) and the cryogenic storage (8).

7. A hydrogen liquefaction process using an installation according to any one of the preceding claims, the process comprising a step of recovering vaporization gas consisting mainly of hydrogen in the cycle circuit (70) of the refrigerator (7), a step of transferring a determined quantity of cycle gas into the feed circuit (2) and a step of recovering vaporization gas consisting mainly of helium from the cryogenic storage to the cycle circuit (70).

8. Method according to the preceding claim, characterized in that the installation is configured to maintain a helium level in the cycle circuit (70) above a determined threshold.

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