Installation for producing a cryogenic fluid

Abstract

The invention relates to an installation (1) for producing a cryogenic fluid, in particular liquefied hydrogen, comprising: - a set of one or more heat exchangers (5, 6) - a first cold box (4) comprising an enclosure (7) which contains at least one cryogenic member such as a portion of the set of one or more heat exchangers (5, 6), the enclosure (7) being intended to be kept under vacuum; - a pressurizable, in particular sealed vessel (12); - a pumping system (11) fluidically connected to the enclosure (7), for placing and / or keeping the inside of the enclosure (7) under vacuum, characterized in that the pumping system (11) is disposed in the pressurizable vessel (12).

Description

Cryogenic fluid production facility

[0001] The present invention relates to an installation for producing and / or storing a cryogenic fluid.

[0002] Cryogenic fluid production installations are known that are equipped with at least one cold box intended to be placed under vacuum. An example of such an installation is a hydrogen liquefier. The vacuum is created by at least one vacuum pump, which is generally located at a distance from the cold box, for example at least 5 meters from it. Indeed, near the cold box, there is a risk of explosion linked to the possible presence of dihydrogen in the atmosphere.

[0003] Keeping the vacuum pump at such a distance from the cold box involves limitations such as unnecessarily increasing the pump power and / or increasing the pressure drop between the draw-off point and the pump, generating additional difficulty in obtaining the desired vacuum. Finally, such an arrangement of the pump relative to the rest of the installation requires a larger footprint and complicates the installation and maintenance of the pipes connecting the pump to the cold box.

[0004] The present invention aims to effectively overcome these drawbacks by proposing an installation for producing and / or storing a cryogenic fluid, in particular liquefied hydrogen, comprising: a set of heat exchanger(s); a first cold box comprising an enclosure in which at least one cryogenic member is arranged, such as a part of the set of heat exchanger(s), the enclosure being intended to be maintained under vacuum; a pressurizable box, in particular a sealed box; a pumping system fluidically connected to the enclosure, for placing and / or maintaining the interior of the enclosure under vacuum, characterized in that the pumping system is arranged in the pressurizable box.

[0005] The invention thus makes it possible to reduce the power of the pumping system and / or to reduce the pressure drop between the draw-off point, for example the enclosure, and the pumping system, while limiting the risks of explosion, in particular if the pumping system cannot be used in an area where such risks exist. Such a reduction in the pressure drop between the draw-off point and the pumping system makes it possible to promote the desired vacuum level.

[0006] The invention therefore makes it possible to use a pumping system that would not be certified "UL NEMA", "NEC", "ATEX", "IEC Ex" or equivalent, even in an area with a risk of explosion, that is to say close to the cold box. The invention thus makes it possible to bring the pumping system closer to the cold box, in particular the cold box responsible for passing the cryogenic fluid to a temperature below -150 °C, in particular to a temperature below or equal to -250 °C.

[0007] According to one embodiment, the pumping system presents a risk of ignition of dihydrogen, in particular by being devoid of “UL NEMA”, “NEC”, “ATEX”, “IEC Ex” or equivalent certification.

[0008] According to one embodiment, the pumping system is fluidically connected to the enclosure by a connection device, to place and / or maintain the interior of the enclosure under vacuum.

[0009] According to one embodiment, the pressurizable box is intended to be maintained under pressure, in particular intended to be maintained at a pressure higher than atmospheric pressure.

[0010] According to one embodiment, the enclosure is fluidically isolated from the pressurizable box.

[0011] According to one embodiment, the pressurizable box is separate from the enclosure.

[0012] According to one embodiment, the pressurizable box is arranged outside the enclosure.

[0013] According to one embodiment, the pressurizable box is separate from the pumping system.

[0014] According to one embodiment, the pumping system is arranged outside the enclosure.

[0015] According to one embodiment, the pressurizable box comprises a pressure measuring device, comprising in particular a Pirani gauge, configured to measure the vacuum in the enclosure and / or in the connection device and / or in the pumping system, for example by being fluidically connected to the connection device.

[0016] According to one embodiment, the pressure measuring device presents a risk of ignition of dihydrogen, in particular by not being certified “UL NEMA”, “NEC”, “ATEX”, “IEC Ex” or equivalent.

[0017] According to one embodiment, the pumping system comprises a primary pumping group, in particular intended to generate a primary vacuum.

[0018] According to one embodiment, the primary pumping unit comprises a cooling circuit to allow the circulation of a cooling fluid such as water.

[0019] According to one embodiment, the pressurizable box comprises a cooling inlet and a cooling outlet, for the circulation of the cooling fluid in the cooling circuit from a source of cooling fluid located outside the pressurizable box.

[0020] According to one embodiment, the pumping system comprises a secondary pumping group intended in particular to generate a secondary vacuum, the secondary pumping group comprising in particular a diffusion pump, the primary pumping group and the secondary pumping group being in particular mounted in series.

[0021] According to one embodiment, the pressurizable box is configured to be swept, in particular continuously, with a sweeping gas such as nitrogen or air such as dry air.

[0022] According to one embodiment, the sweep gas comprises air intended for instruments, for example air known as “instrument air”.

[0023] According to one embodiment, the sweep gas has an H2 impurity level of less than 0.1 ppm, in particular equal to 0 ppm.

[0024] According to one embodiment, the pressurizable box comprises a sweep inlet and a sweep outlet to allow the circulation of the sweep gas through the pressurizable box.

[0025] Such an arrangement allows the pressurizable box to be kept under pressure while allowing the heat generated by the pumping system to be evacuated.

[0026] According to one embodiment, the sweep outlet is intended to be connected to a sweep pipe, in particular configured to allow the sweep gas to be evacuated at a distance from the installation, in particular at a distance greater than 5 meters.

[0027] According to one embodiment, the pressurizable box comprises a purge outlet, for fluidically connecting an outlet of the pumping system to the outside of the pressurizable box, the purge outlet being intended in particular to be connected to a purge pipe for evacuating the purge gas leaving the pumping system remotely from the installation.

[0028] According to one embodiment, the pressurizable box comprises a heater for heating the pumping system, the heater comprising in particular a semiconducting polymer core between two parallel copper conductors.

[0029] Such an arrangement makes it possible to heat the pumping system to ensure an optimized start-up, particularly when commissioning the installation.

[0030] According to one embodiment, the pressurizable box includes a maintenance door.

[0031] According to one embodiment, the installation comprises: a gas circuit to be cooled having an upstream end intended to be connected to a gas source and a downstream end intended to be connected to at least one receiving system, for example cryogenic storage, the set of heat exchanger(s) being configured to be in heat exchange with the gas circuit to be cooled; a pre-cooling device in heat exchange with at least a first part of the set of heat exchanger(s) and configured to pre-cool the gas circuit to be cooled to a first determined temperature, a cryogenic cooling device in heat exchange with at least a second part of the set of heat exchanger(s) and configured to cool the gas circuit to be cooled to a second determined temperature lower than the first temperature, the second part of the set of heat exchanger(s) being arranged in the enclosure.

[0032] According to one embodiment, at least part of the cryogenic cooling device is arranged in the enclosure.

[0033] According to one embodiment, the first part of the exchanger assembly(s) is arranged in the first cold box or in a second cold box separate from the first cold box.

[0034] According to one embodiment, the second cold box is configured to pass the cryogenic fluid to a temperature between -20°C and -150°C.

[0035] According to one embodiment, the second cold box is perlite and / or flushed with nitrogen.

[0036] The invention may also relate to any alternative device comprising any combination of the above or below features.

[0037] The invention will be better understood by reading the following description and examining the accompanying figures. These figures are given only for illustrative purposes but in no way limit the invention.

[0038] This is a schematic representation of an installation according to the invention; and

[0039] This is a schematic representation of a detail of the installation according to the.

[0040] With reference to Figures 1 and 2, an installation 1 for producing and / or storing a cryogenic fluid, in particular liquefied hydrogen, is shown. The installation 1 is, for example, a hydrogen liquefier.

[0041] The installation 1 comprises: a set of heat exchanger(s) 5, 6; a first cold box 4 comprising an enclosure 7 in which at least one cryogenic member is arranged such as a part of the set of heat exchanger(s) 5, 6, the enclosure 7 being intended to be maintained under vacuum; a pressurizable box 12, in particular sealed; a pumping system 11 fluidly connected to the enclosure 7, to place and / or maintain the interior of the enclosure 7 under vacuum.

[0042] As seen in the figure, the pumping system 11 is arranged in the pressurizable box 12.

[0043] The pumping system 11 presents a risk of ignition of dihydrogen. For example, it does not have “UL NEMA”, “NEC”, “ATEX”, or “IEC Ex” certification, for example being incompatible with these certifications. The pumping system 11 cannot therefore be placed near the cold box, which is located in an area in which there is a risk of explosion linked to dihydrogen.

[0044] The pumping system 11 is fluidically connected to the enclosure 7 by a connection device 10, to place and / or maintain the interior of the enclosure 7 under vacuum.

[0045] The pressurizable box 12 comprises a pressure measuring device 15, comprising in particular a pirani gauge, configured to measure the vacuum in the enclosure 7 and / or in the connection device 10 and / or in the pumping system 11, for example by being fluidically connected to the connection device 10.

[0046] The pressure measuring device 15 presents a risk of ignition of dihydrogen. For example, it does not have “UL NEMA”, “NEC”, “ATEX”, or “IEC Ex” type certification, for example being incompatible with these certifications.

[0047] The pumping system 11 comprises a primary pumping group 13, in particular intended to generate a primary vacuum.

[0048] The primary pumping unit 13 comprises a cooling circuit 16 for allowing the circulation of a cooling fluid such as water. The pressurizable box 12 comprises a cooling inlet and a cooling outlet, for the circulation of the cooling fluid in the cooling circuit 16 from a source of cooling fluid located outside the pressurizable box 12.

[0049] The pumping system 11 comprises a secondary pumping group 14 intended in particular to generate a secondary vacuum, the secondary pumping group 14 comprising in particular a diffusion pump, the primary pumping group 13 and the secondary pumping group 14 being in particular mounted in series.

[0050] The pressurizable box 12 is configured to be swept, in particular continuously, with a sweeping gas such as nitrogen or air such as dry air, such as air known as “instrument air”.

[0051] The pressurizable box 12 has a sweep inlet 19 and a sweep outlet 17 to allow circulation of the sweep gas through the pressurizable box 12.

[0052] The sweep outlet 17 is intended to be connected to a sweep pipe, in particular configured to allow the sweep gas to be evacuated at a distance from the installation, in particular at a distance greater than 5 meters.

[0053] The pressurizable box 12 comprises a purge outlet 18, for fluidically connecting an outlet of the pumping system 11 to the outside of the pressurizable box 12, the purge outlet 18 being in particular intended to be connected to a purge pipe for evacuating the purge gas leaving the pumping system 11 at a distance from the installation 1.

[0054] The pressurizable box 12 comprises at least one heater 20 for heating the pumping system 11, the heater 20 comprising in particular a semi-conducting polymer core between two parallel copper conductors.

[0055] The installation 1 comprises: a gas circuit to be cooled 2 having an upstream end 21 intended to be connected to a gas source and a downstream end 22 intended to be connected to at least one receiving system, for example a cryogenic storage 40, the set of heat exchanger(s) 5, 6 being configured to be in heat exchange with the gas circuit to be cooled 2;a pre-cooling device 8 in heat exchange with at least a first part 5 of the heat exchanger(s) assembly 5, 6 and configured to pre-cool the gas circuit to be cooled 2 to a first determined temperature, a cryogenic cooling device 9 in heat exchange with at least a second part 6 of the heat exchanger(s) assembly 5, 6 and configured to cool the gas circuit to be cooled 2 to a second determined temperature lower than the first temperature, the second part 6 of the heat exchanger(s) assembly 5, 6 being arranged in the enclosure 7.;

[0056] At least part of the cryogenic cooling device 9 is arranged in the enclosure 7.

[0057] The pre-cooling device 8 comprises a refrigerator with a refrigeration cycle of a pre-cooling fluid in a pre-cooling circuit, the pre-cooling circuit comprising a member 28 for compressing the pre-cooling fluid.

[0058] The pre-cooling circuit comprises an expansion member 38 for the pre-cooling fluid.

[0059] The cryogenic cooling device 9 comprises a cycle refrigerator for refrigerating a cycle gas in a cycle circuit, the cycle circuit comprising a member 29 for compressing the cycle gas.

[0060] The cycle circuit comprises a cooling member for the compressed cycle gas, an expansion member 39 for the compressed and cooled cycle gas and a heating member for the expanded cycle gas.

[0061] The second determined temperature is between 48 K and 18 K and the first determined temperature is between 100 K and 70 K.

[0062] The first part 5 of the exchanger assembly(s) is arranged in the first cold box 4 or in a second cold box 3.

[0063] The second cold box 3 is perlite and / or swept with nitrogen, in particular without being intended to be placed under vacuum.

[0064] The circuit 2 of gas to be cooled is provided with an expansion member 23 downstream of the downstream end 22, being in particular configured to regulate the pressure in the cryogenic storage 40, the expansion member 23 comprising for example an expansion valve, in particular a Joule-Thomson expansion valve.

[0065] The expansion member 23 and the expansion member 39 of the cycle gas are arranged in the second cold box 4.

[0066] Considering that the atmospheric pressure prevailing around the first and / or the second cold box is approximately 1,000 bar, then the nitrogen pressure prevailing in the second cold box 3 is approximately 1,020 bar, while the pressure inside the enclosure of the first cold box 4 is approximately equal to 5.10-6 mbar.

Claims

Installation (1) for producing and / or storing a cryogenic fluid, in particular liquefied hydrogen, comprising: a set of heat exchanger(s) (5, 6); a first cold box (4) comprising an enclosure (7) in which at least one cryogenic member is arranged, such as a part of the set of heat exchanger(s) (5, 6), the enclosure (7) being intended to be maintained under vacuum; a pressurizable box (12), in particular a sealed box; a pumping system (11) fluidically connected to the enclosure (7), for placing and / or maintaining the interior of the enclosure (7) under vacuum, characterized in that the pumping system (11) is arranged in the pressurizable box (12). Installation (1) according to the preceding claim, the pumping system (11) being fluidically connected to the enclosure (7) by a connection device (10), to place and / or maintain the interior of the enclosure (7) under vacuum. Installation (1) according to the preceding claim, the pressurizable box (12) comprising a pressure measuring device (15), comprising in particular a pirani gauge, configured to measure the vacuum in the enclosure (7) and / or in the connection device (10) and / or in the pumping system (11), for example being fluidically connected to the connection device (10). Installation (1) according to one of the preceding claims, the pumping system (11) comprising a primary pumping group (13), in particular intended to generate a primary vacuum. Installation (1) according to the preceding claim, the pumping system (11) comprising a secondary pumping group (14) in particular intended to generate a secondary vacuum, the secondary pumping group (14) in particular comprising a diffusion pump, the primary pumping group (13) and the secondary pumping group (14) being in particular mounted in series. Installation (1) according to one of the preceding claims, the pressurizable box (12) being configured to be swept, in particular continuously, with a sweeping gas such as nitrogen or air such as dry air. Installation (1) according to one of the preceding claims, the pressurizable box (12) comprising a purge outlet (18), for fluidically connecting an outlet of the pumping system (11) to the outside of the pressurizable box (12), the purge outlet (18) being in particular intended to be connected to a purge pipe for evacuating the purge gas leaving the pumping system (11) at a distance from the installation (1). Installation (1) according to one of the preceding claims, the pressurizable box (12) comprising a heater (20) for heating the pumping system (11), the heater comprising in particular a semiconducting polymer core between two parallel copper conductors. Installation (1) according to one of the preceding claims, comprising: a circuit of gas to be cooled (2) having an upstream end (21) intended to be connected to a gas source and a downstream end (22) intended to be connected to at least one receiving system, for example cryogenic storage (40), the set of heat exchanger(s) (5, 6) being configured to be in heat exchange with the circuit of gas to be cooled (2);a pre-cooling device (8) in heat exchange with at least a first part (5) of the heat exchanger(s) assembly (5, 6) and configured to pre-cool the gas circuit to be cooled (2) to a first determined temperature, a cryogenic cooling device (9) in heat exchange with at least a second part (6) of the heat exchanger(s) assembly (5, 6) and configured to cool the gas circuit to be cooled (2) to a second determined temperature lower than the first temperature, the second part (6) of the heat exchanger(s) assembly (5, 6) being arranged in the enclosure.; Installation (1) according to the preceding claim, the first part (5) of the set of exchanger(s) being arranged in the first cold box (4) or in a second cold box (3).

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