Facility for producing cryogenic fluids
By introducing pressurized chambers and pumping systems into cryogenic fluid production facilities, the problems of increased power and pressure drop and connection complexity caused by the vacuum pump being far from the cold box have been solved, achieving more efficient vacuum acquisition and explosion risk control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2026-04-10
AI Technical Summary
In existing cryogenic fluid production facilities, vacuum pumps need to be kept away from the cold box due to the risk of explosion, which leads to increased power, increased pressure drop, increased space occupation, and complicated connections.
A facility comprising a pressurized chamber and a pumping system is designed, with the pumping system arranged within the pressurized chamber. The housing is placed under vacuum via a connecting device to reduce pressure drop and limit the risk of explosion. An uncertified pumping system is used near the cold box.
This reduces the power and pressure drop of the pumping system, lowers the risk of explosion, simplifies connection complexity, and allows the pumping system to be placed closer to the cold box, ensuring the achievement of vacuum levels.
Smart Images
Figure CN121844172A_ABST
Abstract
Description
[0001] This invention relates to a facility for producing and / or storing cryogenic fluids.
[0002] Cryogenic fluid production facilities are known to be equipped with at least one cold box designed to be placed under vacuum. An example of such a facility is a hydrogen liquefaction unit. The vacuum is applied by at least one vacuum pump, which is typically located at a distance from the cold box (e.g., at least 5 meters away). This is because there is an explosion risk associated with dihydrogen ions that may be present in the atmosphere near the cold box.
[0003] Maintaining the vacuum pump at this distance from the cold chamber means that limitations must be imposed, such as unnecessarily increasing the pump's power and / or increasing the pressure drop between the suction point and the pump, thus creating additional difficulties in achieving the desired vacuum. Finally, this arrangement of the pump relative to the rest of the facility requires a larger footprint and complicates the assembly and support of the piping system that connects the pump to the cold chamber.
[0004] This invention aims to effectively address these drawbacks by providing a facility for the production and / or storage of cryogenic fluids, particularly liquefied hydrogen, the facility comprising:
[0005] - A group of one or more heat exchangers;
[0006] - A first cold box having an outer shell that houses at least one cryogenic unit, such as a portion of one or more heat exchangers in the group, the outer shell being designed to be kept under a vacuum;
[0007] - Pressurized chambers, especially sealed chambers;
[0008] - A pumping system fluidly connected to the housing for placing and / or maintaining the interior of the housing under a vacuum, characterized in that the pumping system is arranged in the pressurizable chamber.
[0009] Therefore, this invention enables a reduction in the power of the pumping system and / or a reduction in the pressure drop between the suction point (e.g., the housing) and the pumping system, while limiting the risk of explosion, particularly where the pumping system cannot be used in areas where such a risk exists. This reduction in the pressure drop between the suction point and the pumping system helps to achieve the desired vacuum level.
[0010] Therefore, this invention enables the use of pumping systems without certifications such as "UL NEMA", "NEC", "ATEX", "IEC Ex", etc., even in areas with explosion risks, i.e., near cold boxes. Thus, this invention allows pumping systems to be placed closer to cold boxes, particularly those responsible for bringing cryogenic fluids to temperatures below -150°C, and especially to temperatures below or equal to -250°C.
[0011] According to one embodiment, the pumping system is at risk of dihydrogen ignition, especially since it lacks certifications such as “UL NEMA”, “NEC”, “ATEX”, “IEC Ex”, etc.
[0012] In one embodiment, the pumping system is fluidly connected to the housing via a connection device to place and / or maintain the interior of the housing under a vacuum.
[0013] According to one embodiment, the pressurizable chamber is designed to be kept under pressure, particularly to be kept under pressure above atmospheric pressure.
[0014] According to one embodiment, the housing is fluidly isolated from the pressurized chamber.
[0015] According to one embodiment, the pressurizable chamber is separate from the outer shell.
[0016] According to one embodiment, a pressurizable chamber is arranged outside the housing.
[0017] According to one embodiment, the pressurizable chamber is separate from the pumping system.
[0018] According to one embodiment, the pumping system is arranged outside the housing.
[0019] According to one embodiment, the pressurizable chamber has a pressure measuring device, which in particular includes a Pirani vacuum gauge and is configured to measure the vacuum in the housing and / or the connecting device and / or the pumping system by means of, for example, fluid connection to the connecting device.
[0020] According to one embodiment, the pressure measuring device is at risk of dihydrogen ignition, especially since it lacks certifications such as “UL NEMA”, “NEC”, “ATEX”, “IEC Ex”, etc.
[0021] According to one embodiment, the pumping system has a primary pumping unit, specifically for generating a primary vacuum.
[0022] According to one embodiment, the primary pumping unit has a cooling circuit for the flow of a coolant (such as water).
[0023] According to one embodiment, the pressurized chamber has a cooling inlet and a cooling outlet for the flow of coolant from a coolant source located outside the pressurized chamber in the cooling circuit.
[0024] According to one embodiment, the pumping system has a secondary pumping unit, particularly for generating a secondary vacuum, which in particular has a diffusion pump, and the primary pumping unit and the secondary pumping unit are connected in series.
[0025] According to one embodiment, the pressurized chamber is configured to be flushed with a flushing gas, particularly a continuous flush, such as nitrogen or air, or dry air.
[0026] According to one embodiment, the flushing gas includes air intended for use with instruments, such as air referred to as "instrument air".
[0027] According to one embodiment, the flushing gas has an H2 impurity content of less than 0.1 ppm, particularly equal to 0 ppm.
[0028] According to one embodiment, the pressurized chamber has a flushing inlet and a flushing outlet for the flow of flushing gas through the pressurized chamber.
[0029] This arrangement allows the pressurized chamber to be kept under pressure while still allowing the heat generated by the pumping system to dissipate.
[0030] According to one embodiment, the flushing outlet is intended to be connected to a flushing duct that is specifically configured to allow flushing gas to be discharged at a distance from the facility, particularly at a distance greater than 5 meters.
[0031] According to one embodiment, the pressurizable chamber has a purge outlet for fluidly connecting the outlet of the pumping system to the outside of the pressurizable chamber, the purge outlet being specifically designed to connect to a purge conduit for discharging purge gas discharged from the pumping system at a distance from the facility.
[0032] According to one embodiment, the pressurizable chamber has a heater for heating the pumping system, which in particular has a semiconductor polymer core between two parallel copper conductors.
[0033] This arrangement allows for the heating of the pumping system to ensure optimized startup, especially when the facility is used for the first time.
[0034] According to one embodiment, the pressurized chamber has an access door.
[0035] According to one embodiment, the facility has:
[0036] - A circuit for the gas to be cooled, the circuit for the gas 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 (e.g., a cryogenic storage device), one or more heat exchangers of the group being configured to exchange heat with the circuit for the gas to be cooled;
[0037] - A precooling device that exchanges heat with at least a first portion of one or more heat exchangers in the group and is configured to precool the circuit for the gas to be cooled to a first given temperature.
[0038] - A cryogenic cooling device that exchanges heat with at least a second portion of one or more heat exchangers in the group and is configured to cool a circuit for the gas to be cooled to a second given temperature below a first temperature, the second portion of one or more heat exchangers in the group being arranged in a housing.
[0039] According to one embodiment, at least a portion of the cryogenic cooling device is arranged within the housing.
[0040] According to one embodiment, a first portion of one or more exchangers in the group is arranged in a first cold box or in a second cold box separate from the first cold box.
[0041] In one embodiment, the second cold box is configured to bring the cryogenic fluid to a temperature between -20°C and -150°C.
[0042] According to one embodiment, the second cold box is filled with perlite and / or flushed with nitrogen.
[0043] The present invention may also relate to any alternative device that includes any combination of the above or below features.
[0044] The invention will be better understood by reading the following description and by studying the accompanying drawings. These drawings are given by way of illustration only and do not limit the invention in any way.
[0045] [ Figure 1 ] Figure 1 It is a schematic representation of a facility according to the invention; and
[0046] [ Figure 2 ] Figure 2 It is based on Figure 1 A schematic representation of the details of the facilities.
[0047] refer to Figure 1 and Figure 2 The diagram shows a facility 1 for the production and / or storage of cryogenic fluids, particularly liquefied hydrogen. Figure 1 Facility 1 in the example is a hydrogen liquefaction unit.
[0048] Facility 1 includes:
[0049] - One or more heat exchangers 5, 6 in a group;
[0050] - A first cold box 4, which has an outer shell 7 that houses at least one cryogenic unit, such as a portion of one or more heat exchangers 5, 6 in the group, and the outer shell 7 is designed to be kept under a vacuum;
[0051] - Pressurized chambers 12, especially sealed chambers;
[0052] - Pumping system 11, which is fluidly connected to housing 7 for placing and / or maintaining the interior of housing 7 under vacuum.
[0053] As in Figure 1 As can be seen, the pumping system 11 is arranged in a pressurized chamber 12.
[0054] Pumping system 11 poses a risk of ignition from dihydrogen. For example, it lacks certifications such as “UL NEMA,” “NEC,” “ATEX,” or “IECEx,” and is therefore incompatible with such certifications. Consequently, pumping system 11 must not be placed near a cold box located in an area with a risk of explosion associated with dihydrogen.
[0055] The pumping system 11 is fluidly connected to the housing 7 via the connecting device 10 so as to place and / or maintain the interior of the housing 7 under a vacuum.
[0056] The pressurizable chamber 12 has a pressure measuring device 15, which specifically includes a Pirani vacuum gauge and is configured to measure the vacuum in the housing 7 and / or the connecting device 10 and / or the pumping system 11 by means of, for example, fluid connection to the connecting device 10.
[0057] The pressure measuring device 15 poses a risk of ignition by dihydrogen. For example, it lacks certifications such as “UL NEMA”, “NEC”, “ATEX”, or “IEC Ex”, and is therefore incompatible with such certifications.
[0058] The pumping system 11 has a primary pumping unit 13, which is specifically used to generate a primary vacuum.
[0059] The primary pumping unit 13 has a cooling circuit 16 for the flow of coolant (such as water). The pressurized chamber 12 has a cooling inlet and a cooling outlet for the flow of coolant from a coolant source located outside the pressurized chamber 12 in the cooling circuit 16.
[0060] The pumping system 11 has a secondary pumping unit 14, which is particularly used to generate a secondary vacuum. The secondary pumping unit 14 has a diffusion pump. The primary pumping unit 13 and the secondary pumping unit 14 are connected in series.
[0061] The pressurized chamber 12 is configured to be flushed with a flushing gas, particularly a continuous flushing gas, such as nitrogen or air, such as dry air, such as air referred to as "instrument air".
[0062] The pressurized chamber 12 has a flushing inlet 19 and a flushing outlet 17 for the flow of flushing gas through the pressurized chamber 12.
[0063] The flushing outlet 17 is intended to connect to a flushing duct that is specifically configured to allow flushing gas to be discharged at a distance from the facility, particularly at a distance greater than 5 meters.
[0064] The pressurized chamber 12 has a purge outlet 18 for fluidly connecting the outlet of the pumping system 11 to the outside of the pressurized chamber 12. The purge outlet 18 is specifically designed to connect to a purge conduit for discharging purge gas discharged from the pumping system 11 at a distance from the facility 1.
[0065] The pressurizable chamber 12 has at least one heater 20 for heating the pumping system 11, the heater 20 having in particular a semiconductor polymer core between two parallel copper conductors.
[0066] Facility 1 includes:
[0067] - A circuit 2 for the gas to be cooled, the circuit for the gas to be cooled 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 (e.g., cryogenic storage device 40), one or more heat exchangers 5, 6 of the group being configured to exchange heat with the circuit 2 for the gas to be cooled.
[0068] - A precooling device 8, which exchanges heat with at least a first portion 5 of one or more heat exchangers 5, 6 in the group, and is configured to precool the circuit 2 for the gas to be cooled to a first given temperature.
[0069] - A cryogenic cooling device 9, which exchanges heat with at least a second portion 6 of one or more heat exchangers 5, 6 in the group, and is configured to cool the circuit 2 for the gas to be cooled to a second given temperature below a first temperature, the second portion 6 of one or more heat exchangers 5, 6 in the group being arranged in a housing 7.
[0070] At least a portion of the cryogenic cooling device 9 is arranged in the housing 7.
[0071] The precooling device 8 includes a cooler having a refrigeration cycle for cooling the precoolant in the precooling circuit, which includes a unit 28 for compressing the precoolant.
[0072] The precooling circuit has an expansion unit 38 for expanding the precoolant.
[0073] The cryogenic cooling device 9 includes a refrigerator having a refrigeration cycle for cooling circulating gas in a circulation loop, the circulation loop including a unit 29 for compressing the circulating gas.
[0074] The circulation loop includes a unit for cooling the compressed circulating gas, an expansion unit 39 for expanding the compressed and cooled circulating gas, and a unit for heating the expanded circulating gas.
[0075] The second given temperature is between 48 K and 18 K, and the first given temperature is between 100 K and 70 K.
[0076] The first part 5 of one or more exchangers in the group is arranged in the first cold box 4 or the second cold box 3.
[0077] The second cold box 3 is filled with perlite and / or flushed with nitrogen, and is not intended to be placed under a vacuum.
[0078] The circuit 2 for the gas to be cooled has an expansion unit 23 located downstream of the downstream end 22. This expansion unit is specifically configured to control the pressure in the cryogenic storage device 40. The expansion unit 23 has, for example, an expansion valve, particularly a Joule-Thomson expansion valve.
[0079] Expansion unit 23 and expansion unit 39 for expanding the circulating gas are arranged in the second cold box 4.
[0080] Given that the dominant atmospheric pressure around the first and / or second cold boxes is approximately 1,000 bar, the dominant nitrogen pressure in the second cold box 3 is approximately 1,020 bar, while the pressure inside the outer shell of the first cold box 4 is approximately 5 x 10⁻⁶ bar. -6 millibar.
Claims
1. A facility (1) for producing and / or storing a cryogenic fluid, in particular liquefied hydrogen, comprising: - a set of one or more heat exchangers (5, 6); - a first cold box (4) having an enclosure (7) which houses at least one cryogenic unit, 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 chamber (12), in particular a sealed chamber; - a pumping system (11) fluidically connected to the enclosure (7) for putting and / or maintaining the inside of the enclosure (7) under vacuum, characterized in that the pumping system (11) is arranged in the pressurizable chamber (12).
2. The facility (1) as claimed in the preceding claim, wherein, The pumping system (11) is fluidically connected to the enclosure (7) by a connection device (10) in order to put and / or maintain the inside of the enclosure (7) under vacuum.
3. The facility (1) as claimed in the preceding claim, wherein, The pressurizable chamber (12) has a pressure measuring device (15), in particular comprising a Pirani gauge, and is configured to measure the vacuum in the enclosure (7) and / or in the connection device (10) and / or in the pumping system (11) by being fluidically connected to the connection device (10), for example.
4. The facility (1) according to one of the preceding claims, wherein The pumping system (11) has a primary pumping unit (13), in particular for generating a primary vacuum.
5. The facility (1) as claimed in the preceding claim, wherein, The pumping system (11) has a secondary pumping unit (14), in particular for generating a secondary vacuum, the secondary pumping unit (14) in particular having a diffusion pump, the primary pumping unit (13) and the secondary pumping unit (14) in particular being connected in series.
6. The facility (1) according to one of the preceding claims, wherein The pressurizable chamber (12) is configured to be purged, in particular continuously purged, with a purge gas, such as nitrogen or air, such as dry air.
7. The facility (1) according to one of the preceding claims, wherein The pressurizable chamber (12) has a purge outlet (18) for fluidically connecting an outlet of the pumping system (11) to the outside of the pressurizable chamber (12), the purge outlet (18) in particular being intended to be connected to a purge duct for discharging purge gas exiting the pumping system (11) at a distance from the facility (1).
8. The facility (1) according to one of the preceding claims, wherein The pressurizable chamber (12) has a heater (20) for heating the pumping system (11), the heater in particular having a semi-conductor polymer core between two parallel copper conductors.
9. The facility (1) according to one of the preceding claims, comprising: - a circuit (2) for a gas to be cooled, 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 installation (40), the set of one or more heat exchangers (5, 6) being configured to exchange heat with the circuit (2) for a gas to be cooled; - a pre-cooling device (8) which exchanges heat with at least a first portion (5) of the set of one or more heat exchangers (5, 6) and is configured to pre-cool the circuit (2) for the gas to be cooled to a first given temperature, - a cryogenic cooling device (9) which exchanges heat with at least a second portion (6) of the set of one or more heat exchangers (5, 6) and is configured to cool the circuit (2) for the gas to be cooled to a second given temperature lower than the first temperature, the second portion (6) of the set of one or more heat exchangers (5, 6) being arranged in the outer casing.
10. The facility (1) as claimed in the preceding claim, wherein, The first portion (5) of the set of one or more exchangers is arranged in the first cold box (4) or in the second cold box (3).