Installation and method for producing liquefied hydrogen

Abstract

This patent describes an installation for producing liquefied hydrogen. The installation includes a hydrogen circuit where gas is cooled by heat exchangers and then stored in a cryogenic facility. A cooling system, featuring a cryogenic refrigerator housed within a thermally insulated cold box, provides the necessary cooling for this process. The installation further includes a withdrawal pipe that carries cold fluid from the storage facility. A portion of this pipe passes through the cold box, establishing a heat-exchange relationship. Control valves on the withdrawal pipe manage the flow of this cold fluid. This allows the system to selectively transfer the fluid's cooling capacity (frigories) to the cold box, thereby assisting the primary refrigeration system and improving the installation's overall efficiency.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a § 371 of International PCT Application PCT / EP2023 / 054362, filed Feb. 22, 2023, which is herein incorporated by reference in its entirety.FIELD OF THE INVENTION

[0002] The invention relates to an installation and to a method for producing liquefied hydrogen.

[0003] The invention relates more particularly to an installation for producing liquefied hydrogen comprising a circuit of hydrogen to be cooled comprising an upstream end intended to be connected to a source of gaseous hydrogen and a downstream end connected to a cryogenic storage means of the installation, the storage means being configured to collect and store liquefied hydrogen, the installation comprising a set of one or more heat exchangers in heat exchange with the circuit of hydrogen to be cooled, the installation comprising a cooling device in heat exchange with all or some of the set of one or more heat exchangers, said cooling device comprising a cryogenic refrigerator arranged at least partially in a first thermally insulated cold box, the installation further comprising at least one withdrawal line having an upstream first end connected to the storage means and a downstream second end connected to a recovery or discharge zone.BACKGROUND OF THE INVENTION

[0004] Hydrogen is liquefied by virtue of methods using heat exchangers cooled by refrigeration systems using working fluids subjected to thermodynamic cycles producing cold via compressors, turbines or expansion valves. The fluid to be liquefied is brought to a temperature of 20 K by the refrigeration system from a temperature of approximately 80 K, which is achieved in an upstream pre-refrigeration system.

[0005] This (refrigeration / pre-refrigeration) equipment, which comprises heat exchangers, is at least partially integrated into one or more thermally insulated enclosures under vacuum in order to be insulated from the external environment (cold boxes).

[0006] A cryogenic liquid product storage means is included in these liquefaction installations in order to maintain continuity of liquid supply in the event of a shutdown of the installation. These cryogenic storage means generate losses through evaporation of liquid due to inputs of heat. This cold gas is either vented or recirculated in the liquefier.

[0007] These refrigeration / liquefaction systems generally involve cooling (that is to say cooling starting from a hot state, for example at ambient temperature) initially starting from hydrogen pre-cooled in the upstream refrigeration system down to temperatures of around 80 K, then by virtue of the refrigeration cycle of the refrigerator to 20 K.

[0008] These cooling operations are relatively long and expensive in terms of energy.SUMMARY OF THE INVENTION

[0009] An aim of the present invention is to overcome all or some of the abovementioned drawbacks of the prior art.

[0010] In an effort to overcome the deficiencies of the prior art discussed, supra,, the installation according to the invention, which is otherwise in accordance with the generic definition thereof given in the preamble above, is essentially characterized in that the withdrawal line comprises, between its first and second ends, a portion passing through the first cold box and in heat exchange therewith, the installation comprising a set of one or more valves for controlling the flow of fluid in the withdrawal line in order to control or not control the transfer of cold energy from a flow of fluid withdrawn from the storage means to the first cold box.

[0011] The installation and its method make it possible to accelerate the cooling of at least one cold box (20 K or more) by using hydrogen from the liquefied hydrogen storage means. This is particularly advantageous when the liquefier is shut down for maintenance. Cold from the storage means makes it possible to keep the liquefier or some of its components, for example one or more heat exchangers and / or other components, at a cold temperature.

[0012] In addition, embodiments of the invention may have one or more of the following features:

[0013] the cryogenic refrigerator is able to switch between an active first state in which it supplies a first cooling power to the first cold box and a shut-down second state in which it supplies a cooling power of zero or of less than the first cooling power to the first cold box, the installation comprising an electronic controller controlling the set of one or more valves and configured to open one or more valves and to circulate fluid from the storage means in the withdrawal line when the refrigerator is in its second state in order for the first cold box to be cooled to, or kept cold at, a predetermined temperature level,

[0014] the withdrawal line comprises a portion passing through a heat exchanger located in the first cold box,

[0015] the heat exchanger located in the first cold box and in heat exchange with the withdrawal line forms part of the set of one or more heat exchangers in heat exchange with the circuit of hydrogen to be cooled, that is to say that said exchanger also comprises a passage through which the circuit of hydrogen to be cooled passes in heat exchange,

[0016] the first end of the withdrawal line is connected to the upper part of the storage means and configured to recover the boil-off gases from said storage means,

[0017] the first end of the withdrawal line is connected to the lower part of the storage means (8) and configured to recover cryogenic liquid from said storage means,

[0018] the installation comprises a pre-cooling device in heat exchange with the circuit of hydrogen to be cooled between the upstream end of the circuit of hydrogen to be cooled and the first cold box, the pre-cooling device being in heat exchange with the hydrogen circuit via at least one heat exchanger of the set of one or more heat exchangers and which is arranged in a second thermally insulated cold box forming part of the installation,

[0019] the installation comprises a withdrawal line having an upstream first end connected to the storage means and a downstream second end connected to a recovery or discharge zone, said withdrawal line comprising, between its first and second ends, a portion passing through the second cold box and in heat exchange therewith, the installation comprising a set of one or more valves for controlling the flow of fluid in the withdrawal line in order to control or not control the transfer of cold energy from the flow of fluid to the second cold box.

[0020] The invention also relates to a method for producing liquefied hydrogen using an installation comprising a circuit of hydrogen to be cooled comprising an upstream end connected to a source of gaseous hydrogen and a downstream end connected to a cryogenic storage means, a set of one or more heat exchangers in heat exchange with the circuit of hydrogen to be cooled, a cooling device in heat exchange with at least some of the set of one or more heat exchangers, said cooling device comprising, arranged at least partially in a first thermally insulated cold box, a cryogenic refrigerator, the installation further comprising at least one withdrawal line having an upstream first end connected to the storage means and a downstream second end connected to a recovery or discharge zone, the withdrawal line comprising, between its first and second ends, a portion passing through the first cold box and in heat exchange therewith, the method comprising a step of stopping or reducing the amount of cold produced by the cooling device in the first cold box and a step of withdrawing fluid from the storage means and of circulating this fluid in the first cold box in order for at least one component in the first cold box to be cooled or kept cold.

[0021] According to other possible particular features:

[0022] the installation comprises a pre-cooling device in heat exchange with the circuit of hydrogen to be cooled between the upstream end of the circuit of hydrogen to be cooled and the first cold box, the pre-cooling device being in heat exchange with the hydrogen circuit via at least one heat exchanger of the set of one or more heat exchangers and arranged in a second thermally insulated cold box forming part of the installation, the method comprising a step of withdrawing fluid from the storage means and of circulating this fluid in the second cold box in order for at least one component therein to be cooled or kept cold,

[0023] during the step of withdrawing fluid from the storage means and of circulating this fluid in the second cold box, the latter is cooled to or kept at a temperature of between 200 and 77 K, and in particular 80 K,

[0024] during the step of withdrawing fluid from the storage means and of circulating this fluid in the first cold box, the latter is cooled to or kept at a temperature of between 77 and 20 K, and in particular 20 K.

[0025] The method may also have at least one of the following operating parameters:

[0026] the hydrogen to be cooled supplied by the hydrogen source is at a pressure of between 10 and 50 bar and a temperature of between 200 and 300 K,

[0027] the hydrogen at the outlet of the second cold box in the circuit of hydrogen to be cooled has a pressure of between 10 and 50 bar and a temperature of between 70 and 100 K, for example between 80 and 90 K,

[0028] the hydrogen at the outlet of the first cold box in the circuit of hydrogen to be cooled has a pressure of between 1 and 2 bar and a temperature of between 18 and 25 K, for example between 20 and 22 K,

[0029] the hydrogen in the withdrawal line at the outlet of the storage means has a pressure of between 1 and 2 bar and a temperature of between 20 and 100 K.

[0030] 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.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, claims, and accompanying drawings. It is to be noted, however, that the drawings illustrate only several embodiments of the invention and are therefore not to be considered limiting of the invention's scope as it can admit to other equally effective embodiments.

[0032] Other particular features and advantages will become apparent upon reading the following description, provided with reference to the figures, in which:

[0033] FIG. 1 shows a schematic partial view illustrating a first example of a structure and of operation of the invention;

[0034] FIG. 2 shows a schematic partial view illustrating a second example of a structure and of operation of the invention.DETAILED DESCRIPTION OF THE INVENTION

[0035] The installation 1 for producing liquefied hydrogen illustrated in FIG. 1 comprises a circuit 2 of hydrogen to be cooled comprising an upstream end 21 intended to be connected to a source of hydrogen (electrolyzer, gaseous hydrogen network, installation for production by reforming or the like) and a downstream end 22 connected to a cryogenic storage means 8.

[0036] The storage means 8 is a cryogenic storage means configured to collect and store liquefied hydrogen produced by the upstream liquefaction unit. To this end, the installation 1 comprises a set of one or more heat exchangers 3, 4 in heat exchange with the circuit 2 of hydrogen to be cooled. At least some of this or these exchangers 3, 4 are cooled by a cooling device comprising a cryogenic refrigerator 5. The cryogenic refrigerator may conventionally have a system that subjects a working fluid (comprising hydrogen and / or helium) to a thermodynamic (compression, cooling, expansion, reheating, etc.) cycle in a working circuit. The working circuit comprises, to this end, one or more compressors, one or more expansion valves or turbines and a set of heat exchangers. At one end of the cycle, the working fluid reaches a cryogenic temperature and is placed in heat exchange with the circuit of hydrogen to be cooled.

[0037] At least some of the components of the refrigerator, in particular heat exchangers, valves, turbines operating at cryogenic temperature, are arranged in a first thermally insulated cold box 15.

[0038] The installation 1 also has at least one withdrawal line 9, 10 having an upstream first end connected to the storage means 8 and a downstream second end connected to a recovery or discharge zone located outside the first cold box, for example at ambient temperature.

[0039] That is to say that the second end of the withdrawal line that discharges the fluid used to cool the cold box (or at least some of its components) is located outside the cold box, for example in a recovery zone that is separate from and warmer than the cold box.

[0040] The withdrawal line 9, 10 comprises, between its first and second ends, a portion passing through the first cold box 15 and in heat exchange therewith. In addition, the installation 1 comprises a set of one or more valves 19 for controlling the flow of fluid in the withdrawal line 9, 10 in order to control or not control the transfer of cold energy from a flow of fluid withdrawn from the storage means 8 to the first cold box 15.

[0041] In this example, the installation 1 comprises two withdrawal lines 9, 10, the first end of which is connected to the upper part of the storage means 8 in order to recover boil-off gas. At the second end, this recovered boil-off gas is generally vented or recirculated in the installation 1 (for example in the circuit 2 of hydrogen to be cooled (at the upstream end and / or further downstream, for example at the inlet of the first cold box 15)). However, when the installation 1 is shut down, this flow of boil-off gas is generally vented.

[0042] In the present installation 1, a withdrawal line 9 comprises a portion passing through the first cold box 15, for example through a heat exchanger 4 located in the first cold box 15. Thus, in particular when the installation 1 is shut down, this flow of cold gas withdrawn from the storage means 8 may be used to cool, and to compensate for the thermal losses of, the first cold box 15. The first cold box 15 may be kept cold and ready to restart without a prior cooling phase (or with reduced cooling).

[0043] For example, the cryogenic refrigerator 5 is able to switch between an active first state in which it supplies a first cooling power to the first cold box 15 and a shut-down second state in which it supplies a cooling power of zero or of less than the first cooling power to the first cold box 15. The installation 1 may comprise an electronic controller 11 controlling the set of one or more valves 19 and configured to open one or more valves 19 and to circulate fluid from the storage means (8) in the withdrawal line 9, 10 when the refrigerator 5 is in its second state in order for the first cold box 15 to be cooled to, or kept cold at, a predetermined temperature level.

[0044] As illustrated, the installation 1 may comprise a pre-cooling device 6 in heat exchange with the circuit 2 of hydrogen to be cooled upstream of the first cold box 15. This pre-cooling device may be provided in order to pre-cool the hydrogen (for example from ambient temperature to approximately 80 K) before the hydrogen in the circuit 2 is cooled and liquefied to a lower temperature in the first cold box 15 (for example approximately 20 K). The pre-cooling device may have, for example, a cold source such as a flow of cryogenic liquid placed in heat exchange with at least one exchanger 3 of the set of heat exchangers (liquid nitrogen loop or other mixture of refrigerants, for example).

[0045] As illustrated, the pre-cooling device 6 may be in heat exchange with the hydrogen circuit 2 via at least one heat exchanger 3 arranged in a second thermally insulated cold box 16. The second cold box 16 may contain other cold components.

[0046] In addition, a withdrawal line 10 may pass through this second cold box 16 in order to release cold thereto, for example in a heat exchanger 3. As previously, a set of one or more valves 19 for controlling the flow of fluid may be provided in order to control the transfer of cold energy from the flow of fluid to the second cold box 16. As previously, the flow of fluid withdrawn from the storage means may be used for cooling the second cold box 16 and in particular at least one heat exchanger 3 and / or other component.

[0047] After passing through the second cold box 16, the downstream end of the withdrawal line 10 may be connected to a recovery or discharge zone outside the cold box 16 (outside the cold boxes).

[0048] In the example in FIG. 1, the first end of the one or more withdrawal lines 9, 10 is connected to the upper part of the storage means 8 in order to recover boil-off gas.

[0049] Of course, and as illustrated in FIG. 2, a withdrawal line 9 may have a first end connected to the lower part of the storage means in order to withdraw liquid therefrom. This liquid may be used as described above to cool one or more cold boxes 15, 16.

[0050] In addition, the configurations of FIG. 1 and FIG. 2 could be combined. That is to say that the installation 1 may have one or more withdrawal lines 9, 10 tapping off liquid and gas from the storage means in order to cool one or more of the cold boxes 15, 16.

[0051] Optionally, the same flow may cool a plurality of cold boxes in series.

[0052] In one possible example of operation, the gaseous hydrogen supplied by the source to the upstream end 21 of the circuit 2 of hydrogen to be cooled is at a pressure (in bar abs) of around 10 to 50 bar and a temperature of around 300 K.

[0053] After pre-cooling in the second cold box 16, the gaseous hydrogen in the circuit 2 may have a pressure (in bar abs) of around 10 to 50 bar and a temperature of around 80 to 90 K.

[0054] After cooling in the first cold box 15, the hydrogen in the circuit 2 may be liquid and may have a pressure (in bar abs) of around 1 to 2 bar and a temperature of around 20 to 22 K (the same is true of the liquid stored in the storage means 8).

[0055] The boil-off gas withdrawn from the storage means 8 has, for example, a pressure (in bar abs) of around 1 to 2 bar and a temperature of around 25 to 100 K. After passing through the first cold box 15 (and cooling the latter), the boil-off gas may be at a pressure of around 1 bar (abs) and a temperature of between 80 and 300 K. The flow of boil-off gas exiting the second cold box 16 has, for example, a pressure (in bar abs) of around 1 to 2 bar and a temperature of around 80 to 300 K. In the case in which liquid is withdrawn from the storage means 8 (pressure of around 1 bar abs and temperature of around 20 to 22 K), after heat exchange in the second cold box 16, its pressure may be reduced (1 bar abs) and its temperature increased (up to 30 to 300 K, for example).

[0056] The invention may be applied to an installation for liquefying a gas other than hydrogen, for example helium.

[0057] 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.

[0058] The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.

[0059] “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.

[0060] “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.

[0061] 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.

[0062] 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.

[0063] All references identified herein are each hereby incorporated by reference into this application in their entireties, as well as for the specific information for which each is cited.

Claims

1-12. (canceled)13. An installation for producing liquefied hydrogen comprising:a circuit of hydrogen to be cooled comprising an upstream end configured to be connected to a source of gaseous hydrogen and a downstream end connected to a cryogenic storage means of the installation, the cryogenic storage means being configured to collect and store liquefied hydrogen;a set of one or more heat exchangers in heat exchange with the circuit of hydrogen to be cooled;a cooling device in heat exchange with all or some of the set of one or more heat exchangers, said cooling device comprising a cryogenic refrigerator arranged at least partially in a first thermally insulated cold box, the cryogenic refrigerator having a system that subjects a working fluid comprising hydrogen and / or helium to a thermodynamic compression, cooling, expansion or reheating cycle in a working circuit, the working circuit comprising one or more compressors, one or more expansion valves or turbines, and a set of heat exchangers;a first withdrawal line having an upstream first end connected to the storage means and a downstream second end connected to a recovery or discharge zone located outside the first cold box, the first withdrawal line comprising, between the upstream first end and the downstream second end, a portion passing through the first cold box and in heat exchange therewith;a set of one or more valves configured to control the flow of fluid in the first withdrawal line thereby controlling a transfer of cold energy from a flow of fluid withdrawn from the storage means to the first cold box, the cryogenic refrigerator being able to switch between an active first state in which the cryogenic refrigerator supplies a first cooling power to the first cold box and a shut-down second state in which the cryogenic refrigerator supplies a cooling power of zero or of less than the first cooling power to the first cold box; andan electronic controller configured to control the set of one or more valves and configured to open at least one valve of the set of one or more valves and to circulate fluid from the storage means in the first withdrawal line when the cryogenic refrigerator is in the second state in order for the first cold box to be cooled to, or kept cold at, a predetermined temperature level,wherein the downstream second end of the first withdrawal line is located outside the cryogenic refrigerator and outside the working cycle.

14. The installation as claimed in claim 13, wherein the first withdrawal line comprises a portion passing through a heat exchanger located in the first cold box.

15. The installation as claimed in claim 14, wherein the heat exchanger located in the first cold box and in heat exchange with the first withdrawal line forms part of the set of one or more heat exchangers in heat exchange with the circuit of hydrogen to be cooled, such that said heat exchanger also comprises a passage through which the circuit of hydrogen to be cooled passes in heat exchange.

16. The installation as claimed in claim 13, wherein the first end of the first withdrawal line is connected to the upper part of the storage means and configured to recover the boil-off gases from said storage means.

17. The installation as claimed in claim 13, wherein the first end of the first withdrawal line is connected to the lower part of the storage means and configured to recover cryogenic liquid from said storage means.

18. The installation as claimed in claim 13, further comprising a pre-cooling device in heat exchange with the circuit of hydrogen to be cooled between the upstream end of the circuit of hydrogen to be cooled and the first cold box, the pre-cooling device being in heat exchange with the hydrogen circuit via at least one heat exchanger of the set of one or more heat exchangers and which is arranged in a second thermally insulated cold box forming part of the installation.

19. The installation as claimed in claim 18, further comprising a second withdrawal line having an upstream first end connected to the storage means and a downstream second end connected to a recovery or discharge zone, said second withdrawal line comprising, between its first and second ends, a portion passing through the second cold box and in heat exchange therewith, the installation comprising a set of one or more valves for controlling the flow of fluid in the second withdrawal line in order to control or not control the transfer of cold energy from the flow of fluid to the second cold box.

20. A method for producing liquefied hydrogen, the method comprising the steps of:providing the installation as claimed in claim 13;stopping or reducing the amount of cold produced by the cooling device in the first cold box;withdrawing fluid from the storage means and circulating said fluid in the first cold box in order for the first cold box and at least the at least one first component in the first cold box to be cooled or kept cold.

21. The method as claimed in claim 20, wherein the installation further comprises a pre-cooling device in heat exchange with the circuit of hydrogen to be cooled between the upstream end of the circuit of hydrogen to be cooled and the first cold box, the pre-cooling device being in heat exchange with the hydrogen circuit via at least one heat exchanger of the set of one or more heat exchangers and arranged in a second thermally insulated cold box forming part of the installation, the second cold box comprising, for example, at least one second additional component, the method comprising a step of withdrawing fluid from the storage means and of circulating this fluid in the second cold box in order for the second cold box and for example at least one heat exchanger and / or the at least one second additional component therein to be cooled or kept cold.

22. The method as claimed in claim 21, wherein, during the step of withdrawing fluid from the storage means and of circulating this fluid in the second cold box, the latter is cooled to or kept at a temperature of between 200 and 77 K, and in particular 80 K.

23. The method as claimed in claim 20, wherein, during the step of withdrawing fluid from the storage means and of circulating this fluid in the first cold box, the latter is cooled to or kept at a temperature of between 77 and 20 K, and in particular 20 K.

24. The method as claimed in claim 21, further comprising at least one of the following operating parameters:the hydrogen to be cooled supplied by the hydrogen source is at a pressure of between 10 and 50 bar and a temperature of between 200 and 300 K,the hydrogen at the outlet of the second cold box in the circuit of hydrogen to be cooled has a pressure of between 10 and 50 bar and a temperature of between 70 and 100 K, for example between 80 and 90 K,the hydrogen at the outlet of the first cold box in the circuit of hydrogen to be cooled has a pressure of between 1 and 2 bar and a temperature of between 18 and 25 K, for example between 20 and 22 K,the hydrogen in the withdrawal line at the outlet of the storage means has a pressure of between 1 and 2 bar and a temperature of between 20 and 100 K.

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