Installation and method for producing liquefied hydrogen
Patent Information
- Application Number
- EP2023707886
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-02-22
- Publication Date
- 2025-12-31
AI Technical Summary
The existing processes for producing liquefied hydrogen are energy-intensive and costly due to long and inefficient cooling operations, particularly when the liquefaction system is shut down for maintenance, leading to thermal losses and the need for prolonged re-cooling.
The installation incorporates a withdrawal pipe with a transiting portion through a cold box for thermal exchange, allowing for controlled fluid flow using valves to utilize stored liquefied hydrogen to maintain cold temperatures, thereby accelerating cooling and reducing energy consumption during system downtime.
This approach enables faster cooling and reduced energy costs by utilizing stored liquefied hydrogen to keep components at low temperatures, minimizing thermal losses and eliminating the need for extensive re-cooling when the system is restarted.
Smart Images
Figure EP2023054362_29082024_PF_FP_ABST
Abstract
Description
Installation and process for the production of liquefied hydrogen
[0001] The invention relates to a plant and a method for producing liquefied hydrogen.
[0002] The invention relates more particularly to a liquefied hydrogen production installation comprising a hydrogen circuit 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 of the installation, the storage being configured to collect and store liquefied hydrogen, the installation comprising a set of heat exchanger(s) in heat exchange with the hydrogen circuit to be cooled, the installation comprising a cooling device in heat exchange with all or part of the set of heat exchanger(s), 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 pipe having a first upstream end connected to the storage and a second downstream end connected to a recovery or discharge zone.,
[0003] Hydrogen is liquefied using processes that use 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 20K by the refrigeration system from a temperature of approximately 80K, obtained in an upstream pre-refrigeration system.
[0004] These devices (refrigeration / pre-refrigeration) which include heat exchangers are integrated at least in part in one or more thermally insulated vacuum enclosures in order to be isolated from the external environment (cold boxes).
[0005] A storage facility for the produced cryogenic liquid is included in these liquefaction facilities to maintain a continuous supply of liquid in the event of a shutdown. These cryogenic storage facilities generate losses through liquid evaporation due to heat input. This cold gas is either vented or recirculated into the liquefier.
[0006] The cooling (i.e. cooling from a hot state, for example at room temperature) of these refrigeration / liquefaction systems is generally carried out initially using pre-cooled hydrogen in the upstream refrigeration system to temperatures of around 80K, then using the refrigerator's refrigeration cycle to 20K.
[0007] These cold weather sessions are relatively long and costly in terms of energy.
[0008] An aim of the present invention is to overcome all or part of the drawbacks of the prior art noted above.
[0009] To this end, the installation according to the invention, moreover in accordance with the generic definition given in the preamble above, is essentially characterized in that the withdrawal pipe comprises between its first and second ends, a portion passing through the first cold box and in heat exchange with the latter, the installation comprising a set of valve(s) for controlling the flow of fluid in the withdrawal pipe to control or not the transfer of frigories from a flow of fluid withdrawn from storage to the first cold box.
[0010] The installation and its process make it possible to accelerate the cooling of at least one cold box (20K or more) by using hydrogen from the liquefied hydrogen storage. This is particularly advantageous when the liquefier is shut down for maintenance. Cold from the storage 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.
[0011] Furthermore, embodiments of the invention may include one or more of the following features: the cryogenic refrigerator is switchable between a first operating state in which it provides a first cold power in the first cold box and a second off state in which it provides a cold power that is zero or less than the first cold power in the first cold box, the installation comprising an electronic controller controlling the set of valve(s) and configured to ensure opening of the valve(s) and circulation of fluid from the storage in the draw-off pipe when the refrigerator is in its second state to cool or keep the first cold box cold at a determined temperature level, the draw-off pipe comprises a portion passing through a heat exchanger located in the first cold box,the heat exchanger located in the first cold box and in heat exchange with the withdrawal pipe is part of the set of heat exchanger(s) in heat exchange with the hydrogen circuit to be cooled, that is to say that said exchanger also comprises a passage in which the hydrogen circuit to be cooled passes in heat exchange, the first end of the withdrawal pipe is connected to the upper part of the storage and configured to recover the vaporization gases from said storage, the first end of the withdrawal pipe is connected to the lower part of the storage (8) and configured to recover cryogenic liquid from said storage, the installation comprises a pre-cooling device in heat exchange with the hydrogen circuit to be cooled between the upstream end of the hydrogen circuit 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 heat exchanger(s) and which is arranged in a second thermally insulated cold box and forming part of the installation, the installation comprises a withdrawal pipe having a first upstream end connected to the storage and a second downstream end connected to a recovery or discharge zone, said withdrawal pipe comprising between its first and second ends, a portion passing through the second cold box and in heat exchange with the latter, the installation comprising a set of valve(s) for controlling the flow of fluid in the withdrawal pipe to control or not the transfer of frigories from the flow of fluid to the second cold box.,
[0012] The invention also relates to a method for producing liquefied hydrogen using an installation comprising a hydrogen circuit to be cooled comprising an upstream end connected to a source of gaseous hydrogen and a downstream end connected to a cryogenic storage, a set of heat exchanger(s) in heat exchange with the hydrogen circuit to be cooled, a cooling device in heat exchange with at least part of the set of heat exchanger(s), 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 pipe having a first upstream end connected to the storage and a second downstream end connected to a recovery or discharge zone, the withdrawal pipe comprising between its first and second ends,a portion passing through the first cold box and in heat exchange with the latter, the method comprising a step of stopping or reducing the quantity of cold produced by the cooling device in the first cold box and a step of withdrawing fluid from the storage and circulating this fluid in the first cold box to cool or keep cold at least one component in the first cold box.,
[0013] According to other possible features: - the installation comprises a pre-cooling device in heat exchange with the hydrogen circuit to be cooled between the upstream end of the hydrogen circuit 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 heat exchanger(s) 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 and circulating this fluid in the second cold box to cool or keep cold at least one component in the latter, during the step of withdrawing fluid from the storage and circulating this fluid in the second cold box the latter is cooled or kept at a temperature of between 200 and 77K and in particular 80K,during the step of withdrawing fluid from storage and circulating this fluid in the first cold box, the latter is cooled or maintained at a temperature between 77 and 20K and in particular 20K.,
[0014] The method may further comprise 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 300K, the hydrogen at the outlet of the second cold box in the hydrogen circuit to be cooled has a pressure of between 10 and 50 bar and a temperature of between 70 and 100K, for example between 80 and 90K, the hydrogen at the outlet of the first cold box in the hydrogen circuit to be cooled has a pressure of between 1 and 2 bar and a temperature of between 18 and 25K, for example between 20 and 22K, the hydrogen in the withdrawal line at the outlet of the storage has a pressure of between 1 and 2 bar and a temperature of between 20 and 100K.
[0015] 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.
[0016] Other features and advantages will appear on reading the description below, made with reference to the figures in which:
[0017] represents a schematic and partial view illustrating a first example of structure and operation of the invention,
[0018] represents a schematic and partial view illustrating a second example of structure and operation of the invention.
[0019] The liquefied hydrogen production installation 1 illustrated in the comprises a hydrogen circuit 2 to be cooled comprising an upstream end 21 intended to be connected to a hydrogen source (electrolyzer, gaseous hydrogen network, reforming production installation or other) and a downstream end 22 connected to a cryogenic storage 8.
[0020] The storage 8 is of the cryogenic type configured to collect and store liquefied hydrogen produced by the upstream liquefaction unit. For this purpose, the installation 1 comprises a set of heat exchanger(s) 3, 4 in heat exchange with the hydrogen circuit 2 to be cooled. At least a portion of this or these exchanger(s) 3, 4 are cooled by a cooling device comprising a cryogenic refrigerator 5. The cryogenic refrigerator may conventionally comprise a system subjecting a working fluid (comprising hydrogen and / or helium) to a thermodynamic cycle (compression, cooling, expansion, reheating, etc.) in a working circuit. The working circuit comprises for this purpose one or more compressors, one or more turbines or expansion valve(s) and a set of heat exchangers. At one end of the cycle, the working fluid reaches a cryogenic temperature and is put into heat exchange with the hydrogen circuit to be cooled.
[0021] 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.
[0022] The installation 1 further comprises at least one withdrawal pipe 9, 10 having a first upstream end connected to the storage 8 and a second downstream end connected to a recovery or discharge zone located outside the first cold box, for example at ambient temperature.
[0023] That is, the second end of the draw-off line that discharges the fluid used to cool the cold box (or at least part of its components) is located outside the cold box, for example in a recovery zone separate from the cold and warmer box.
[0024] The withdrawal pipe 9, 10 comprises, between its first and second ends, a portion passing through the first cold box 15 and in heat exchange with the latter. In addition, the installation 1 comprises a set of valve(s) 19 for controlling the flow of fluid in the withdrawal pipe 9, 10 to control or not the transfer of frigories from a flow of fluid withdrawn from the storage 8 to the first cold box 15.
[0025] In this example, the installation 1 comprises two withdrawal pipes 9, 10, the first end of which is connected to the upper part of the storage 8 to recover vaporization gas (“Boil-off” gas). At the second end, this recovered vaporization gas is generally vented or recirculated in the installation 1 (for example in the hydrogen circuit 2 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 vaporization gas is generally vented.
[0026] In the present installation 1, a withdrawal pipe 9 comprises a portion passing through the first cold box 15, for example in a heat exchanger 4 located in the first cold box 15. Thus, in particular when the installation 1 is stopped, this flow of cold gas withdrawn from the storage 8 can be used to cool and compensate for the thermal losses of the first cold box 15. The first cold box 15 can be kept cold ready to restart without a prior cooling phase (or with reduced cooling).
[0027] For example, the cryogenic refrigerator 5 is switchable between a first operating state in which it provides a first cold power in the first cold box 15 and a second stopping state in which it provides a cold power that is zero or less than the first cold power in the first cold box 15. The installation 1 may comprise an electronic controller 11 controlling the set of valve(s) 19 and configured to ensure opening of the valve(s) 19 and circulation of fluid from the storage (8) in the withdrawal pipe 9, 10 when the refrigerator 5 is in its second state to cool or keep the first cold box 15 cold at a determined temperature level.
[0028] As illustrated, the installation 1 may comprise a pre-cooling device 6 in heat exchange with the hydrogen circuit 2 to be cooled upstream of the first cold box 15. This pre-cooling device may be provided to ensure pre-cooling of the hydrogen (for example from ambient temperature to approximately 80k) before the hydrogen of the circuit 2 is cooled and liquefied to a lower temperature in the first cold box 15 (for example approximately 20k). The pre-cooling device may comprise, for example, a cold source such as a flow of cryogenic liquid put into heat exchange with at least one exchanger 3 of the set of heat exchangers (liquid nitrogen loop or other mixture of refrigerants for example).
[0029] 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.
[0030] In addition, a withdrawal pipe 10 can pass through this second cold box 16 to release cold there, for example into a heat exchanger 3. As previously, a set of fluid flow control valve(s) 19 can be provided to control the transfer of frigories from the fluid flow to the second cold box 16. As previously, the fluid flow withdrawn from the storage can be used for cooling the second cold box 16 and in particular at least one heat exchanger 3 and / or other component.
[0031] After passing through the second cold box 16, the downstream end of the withdrawal pipe 10 can be connected to a recovery or discharge zone outside the cold box 16 (outside the cold boxes).
[0032] In the example of the first end of the withdrawal pipe(s) 9, 10 is connected to the upper part of the storage 8 to recover vaporization gas.
[0033] Of course, and as illustrated in the, a withdrawal pipe 9 may have a first end connected to the lower part of the storage to withdraw liquid therefrom. This liquid may be used as described above to cool one or more cold boxes 15, 16.
[0034] Furthermore, the configurations of the set could be combined. That is, the installation 1 may comprise one or more withdrawal pipes 9, 10 taking liquid and gas from the storage to cool one or more of the cold boxes 15, 16.
[0035] The same flow can possibly cool several cold boxes in series.
[0036] In a possible operating example, the gaseous hydrogen supplied by the source at the upstream end 21 of the hydrogen circuit 2 to be cooled is at a pressure (in bar abs) of the order of 10 to 50 bar and a temperature of the order of 300K.
[0037] After pre-cooling in the second 16 cold box, the hydrogen gas of circuit 2 can have a pressure (in bar abs) of the order of 10 to 50 bar and a temperature of the order of 80 to 90K.
[0038] After cooling in the first 15 cold box, the hydrogen in circuit 2 can be liquid and can have a pressure (in bar abs) of the order of 1 to 2 bar and a temperature of the order of 20 to 22K (same for the liquid stored in storage 8).
[0039] The vaporization gas withdrawn from the storage 8 has for example a pressure (in bar abs) of the order of 1 to 2 bar and a temperature of the order of 25 to 100K. After passing into the first cold box 15 (and cooling of the latter) the vaporization gas can be at a pressure of the order of 1 bar (abs) and a temperature of between 80 and 300K. The flow of vaporization gas leaving the second cold box 16 has for example a pressure (in bar abs) of the order of 1 to 2 bar and a temperature of the order of 80 to 300K.
[0040] In the case where liquid is drawn from storage 8 (pressure of the order of 1 bar abs and temperature of the order of 20 to 22K), after heat exchange in the second cold box 16 its pressure can be reduced (1 bar abs) and its temperature increased (up to 30 to 300K for example).
[0041] The invention can be applied to a liquefaction installation for a gas other than hydrogen, for example helium.
Claims
Liquefied hydrogen production plant comprising a hydrogen circuit (2) to be cooled comprising an upstream end (21) intended to be connected to a source of gaseous hydrogen and a downstream end (22) connected to a cryogenic storage (8) of the plant (1), the storage (8) being configured to collect and store liquefied hydrogen, the plant (1) comprising a set of heat exchanger(s) (3, 4) in heat exchange with the hydrogen circuit (2) to be cooled, the plant (1) comprising a cooling device in heat exchange with all or part of the set of heat exchanger(s) (3, 4), said cooling device comprising a cryogenic refrigerator (5) arranged at least partially in a first thermally insulated cold box (15), the plant (1) further comprising at least one first pipe (9,10) withdrawal having a first upstream end connected to the storage (8) and a second downstream end connected to a recovery or discharge zone located outside the first cold box (15), the first withdrawal pipe (9, 10) comprising between its first and second ends, a portion passing through the first cold box (15) and in heat exchange with the latter, the installation (1) comprising a set of valve(s) (19) for controlling the flow of fluid in the first withdrawal pipe (9, 10) to control or not the transfer of frigories of a flow of fluid withdrawn from the storage (8) to the first cold box (15), the cryogenic refrigerator (5) being switchable between a first operating state in which it provides a first cold power in the first cold box (15) and a second stopping state in which it provides a cold power zero or less than the first cold power in the first cold box (15),the installation (1) comprising an electronic controller (11) controlling the set of valve(s) (19) and configured to ensure opening of the valve(s) (19) and circulation of fluid from the storage (8) in the first withdrawal pipe (9, 10) when the refrigerator (5) is in its second state to cool or keep cold the first cold box (15) at a determined temperature level., Installation according to claim 1, characterized in that the first withdrawal pipe (9, 10) comprises a portion passing through a heat exchanger (4) located in the first cold box (15). Installation according to claim 2, characterized in that the heat exchanger (4) located in the first cold box (15) and in heat exchange with the first withdrawal pipe (9, 10) is part of the set of heat exchanger(s) (3, 4) in heat exchange with the hydrogen circuit (2) to be cooled, that is to say that said exchanger also comprises a passage in which the hydrogen circuit (2) to be cooled passes in heat exchange. Installation according to any one of claims 1 to 3, characterized in that the first end of the first withdrawal pipe (9, 10) is connected to the upper part of the storage (8) and configured to recover the vaporization gases from said storage (8). Installation according to any one of claims 1 to 4, characterized in that the first end of the first withdrawal pipe (9, 10) is connected to the lower part of the storage (8) and configured to recover cryogenic liquid from said storage (8). Installation according to any one of claims 1 to 5, characterized in that it comprises a pre-cooling device (6) in heat exchange with the hydrogen circuit (2) to be cooled between the upstream end (21) of the hydrogen circuit (2) to be cooled and the first cold box (15), the pre-cooling device being in heat exchange with the hydrogen circuit (2) via at least one heat exchanger (3) of the set of heat exchanger(s) and which is arranged in a second cold box (16) which is thermally insulated and forming part of the installation (1). Installation according to claim 6, characterized in that it comprises a second withdrawal pipe (10) having a first upstream end connected to the storage (8) and a second downstream end connected to a recovery or discharge zone, said second withdrawal pipe (10) comprising between its first and second ends, a portion passing through the second cold box (16) and in heat exchange with the latter, the installation (1) comprising a set of valve(s) (19) for controlling the flow of fluid in the second withdrawal pipe (10) to control or not the transfer of frigories from the flow of fluid to the second cold box (16). A method for producing liquefied hydrogen using an installation (1) comprising a circuit (2) of hydrogen to be cooled comprising an upstream end (21) connected to a source of gaseous hydrogen and a downstream end (22) connected to a cryogenic storage (8), a set of heat exchanger(s) (3, 4) in heat exchange with the circuit (2) of hydrogen to be cooled, a cooling device in heat exchange with at least part of the set of heat exchanger(s) (3, 4), said cooling device comprising, arranged at least partially in a first thermally insulated cold box (15), a cryogenic refrigerator (5), the first cold box (15) of the installation comprising at least one component, for example at least one heat exchanger of the set of heat exchangers, the installation (1) further comprising at least one first pipe (9,10) withdrawal having a first upstream end connected to the storage (8) and a second downstream end connected to a recovery or discharge zone located outside the first cold box, the first withdrawal pipe (9, 10) comprising between its first and second ends, a portion passing through the first cold box (15) and in heat exchange with the latter, the method comprising a step of stopping or reducing the quantity of cold produced by the cooling device in the first cold box (15) and a step of withdrawing fluid from the storage (8) and circulating this fluid in the first cold box (15) to cool or keep cold the first cold box (15) and for example at least one component in the first cold box (15)., Method according to claim 8, characterized in that the installation (1) comprises a pre-cooling device (16) in heat exchange with the hydrogen circuit (2) to be cooled between the upstream end (21) of the hydrogen circuit (2) to be cooled and the first cold box (15), the pre-cooling device (16) being in heat exchange with the hydrogen circuit (2) via at least one heat exchanger (3) of the set of heat exchanger(s) and arranged in a second thermally insulated cold box (16) forming part of the installation (1), the second cold box (16) comprising for example at least one additional component, the method comprising a step of withdrawing fluid from the storage (8) and circulating this fluid in the second cold box (16) to cool or keep the second cold box (16) cold and for example at least one heat exchanger and / or additional component in the latter. Method according to claim 9, characterized that, during the step of withdrawing fluid from the storage (8) and circulating this fluid in the second (16) cold box, the latter is cooled or maintained at a temperature between 200 and 77K and in particular 80K. Method according to any one of claims 8 to 10, characterized during the step of withdrawing fluid from the storage (8) and circulating this fluid in the first cold box (15), the latter is cooled or maintained at a temperature between 77 and 20K and in particular 20K. Method according to any one of claims 9 or 10, characterized by 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 300K, the hydrogen at the outlet of the second cold box (16) in the circuit (2) of hydrogen to be cooled has a pressure of between 10 and 50 bar and a temperature of between 70 and 100K, for example between 80 and 90K, the hydrogen at the outlet of the first cold box (15) in the circuit (2) of hydrogen to be cooled has a pressure of between 1 and 2 bar and a temperature of between 18 and 25K, for example between 20 and 22K, the hydrogen in the withdrawal pipe (9, 10) at the outlet of the storage (8) has a pressure of between 1 and 2 bar and a temperature of between 20 and 100K.