AU2023355501A1

AU2023355501A1 - Low-temperature refrigeration device

Info

Publication number: AU2023355501A1
Application number: AU2023355501A
Authority: AU
Inventors: Pierre BARJHOUX; Guillaume DELAUTRE; Fabien Durand; François LAGOUTTE
Original assignee: Air Liquide SA; LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Current assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date: 2022-10-03
Filing date: 2023-09-08
Publication date: 2025-05-15
Also published as: CA3267455A1; KR20250083515A; WO2024074263A1; CN119836551A; FR3140417A1; JP2025532157A; EP4599198A1; FR3140417B1

Abstract

The invention relates to a refrigeration device comprising a circuit for a working fluid and comprising a mechanism (3) for compressing the working fluid with at least one compressor, a mechanism (4, 7) for cooling the working fluid, a mechanism (6) for expanding the working fluid with at least one expansion turbine (6) and a mechanism (7) for heating the working fluid, the device comprising an insulated cold box (9) housing a heat exchanger (7) and the at least one turbine (6), the cold box (9) having a cylindrical shape extending in a longitudinal direction about a central axis (10), the at least one turbine (6) being arranged in the cold box (9) in a transversely offset manner with respect to its central longitudinal axis (10).

Description

Description Title of the invention: Low-temperature refrigeration device

The invention relates to a low-temperature refrigeration device. The invention relates more particularly to a device for refrigeration and/or liquefaction at low temperature, i.e. at a temperature of between minus 100 degrees centigrade and minus 273 degrees centigrade, the refrigeration device comprising a working circuit forming a loop and containing a working fluid, the working circuit comprising a mechanism for compressing the working fluid comprising at least one compressor, a mechanism for cooling the working fluid, a mechanism for expanding the working fluid comprising at least one expansion turbine, and a mechanism for heating the working fluid, the working circuit being configured to subject the working fluid to a determined thermodynamic cycle in which the working fluid reaches a relatively low temperature at a cold end of the cycle, the device comprising a refrigeration heat exchanger intended to extract heat from at least one member or fluid through heat exchange with the working fluid, the device comprising a thermally insulated cold box housing the refrigeration heat exchanger and the at least one expansion turbine, the cold box having a cylindrical overall shape extending in a longitudinal direction about a central axis, said axis preferably being horizontal in the use configuration, the at least one turbine being arranged in the cold box (9) in the vicinity of a first longitudinal end of the cold box, the at least one turbine being mounted longitudinally in the cold box between the refrigeration heat exchanger and the longitudinal end wall of the cold box. The invention relates in particular to cryogenic refrigerators or liquefiers comprising turbomachines using cryogenic turbines. These refrigerators also have cooling and/or heating heat exchangers between expansion stages and a cryogenic chamber referred to as a cold box (and thermally insulated, for example under vacuum)

. These refrigerators are mounted on a structure and one problem consists in maximizing the ratio between the capacity of the system (and therefore the number of components) and its dimensions in width and height. This optimization makes it possible either to increase the capacity of the system while remaining within a fixed transport size or to minimize the dimensions in relation to a fixed capacity. Another constraint consists in producing a reliable assembly that does not require any welding at the destination site of the refrigerator. In one known embodiment, the turbines are mounted on the side of the cold box. This makes it possible to mount a large number of turbines by separating the manufacturing of the turbines and of the cold box. The heat exchangers are installed in the vicinity of the turbines, without size limitation. However, this solution has the drawback that the turbines exceed the transport size. The turbines are therefore transported separately and connected (welded) at the destination site. The exchangers are mounted either directly on the turbines or on a separate support. This solution requires additional assembly costs and time after manufacturing. Another solution consists in installing equipment and in particular the turbines on the top of the cold box. However, this solution is not suitable for high-power turbines that require exchangers installed on a separate support. This requires the connecting pipework to be installed on site. Another solution consists in mounting a single turbine on the bottom of the cold box at the central axis of revolution. The heat exchanger of the turbine and the heat exchanger of the compressor may be combined into a single piece of equipment. In the case of a refrigerator producing very low temperatures, it is however necessary to provide a plurality of turbine stages.

The heat exchanger is installed adjacent to the chamber under vacuum, thereby degrading the capacity/dimensions ratio when there are a plurality of heat exchangers and/or if the diameter of the exchanger increases. An aim of the present invention is to overcome all or some of the abovementioned drawbacks of the prior art. To this end, the 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 at least one turbine is mounted so as to be transversely offset with respect to the central longitudinal axis of the cold box. In addition, embodiments of the invention may comprise one or more of the following features: - the at least one turbine is mounted at the end of a shaft of a motor also driving a compressor of the compression mechanism, the motor being situated outside the cold box, the end of the shaft bearing the turbine being mounted so as to pass through the end wall of the cold box in a fluid tight manner, - the end of the shaft bearing the turbine is mounted so as to pass through the end wall of the cold box in a fluid tight manner via a tubular tapping connection mounted so as to protrude on the outer surface of the longitudinal end wall of the cold box, - the longitudinal end wall of the cold box has a shape that is domed toward the outside of the cold box, - the device comprises at least one additional turbine arranged in the cold box in the vicinity of a second longitudinal end of the cold box, the at least one additional turbine being mounted longitudinally in the cold box between the refrigeration heat exchanger and the end wall of the second longitudinal end of the cold box, so as to be transversely offset with respect to the central longitudinal axis of the cold box,

- the device is arranged in and/or on a support,

- the working circuit comprises at least one heat exchanger situated outside the cold box and forming part of the mechanism for cooling the working fluid, said at least one heat exchanger being mounted in and/or on the support in a plane perpendicular to the longitudinal direction,

- the device comprises a plurality of heat exchangers situated outside the cold box and forming part of the mechanism for cooling the working fluid, said heat exchangers being mounted in and/or on the support in respective planes perpendicular to the longitudinal direction, - the support comprises at least one of: a set of one or more legs for supporting the cold box, a frame,

- the support is made up of a plurality of structures assembled in the longitudinal direction. 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. Further particular features and advantages will become apparent upon reading the description below, which is provided with reference to the figures, in which: Brief description of the figures The invention will be better understood upon reading the following description, which is given solely by way of example and with reference to the appended drawings, in which:

[Fig. 1] is a partial schematic top view of a refrigeration device according to a first exemplary embodiment,

[Fig. 2] is a partial schematic side view of the device from

[Fig. 1],

[Fig. 3] is a simplified schematic view of a detail of the device from [Fig. 1] symbolizing the working circuit,

[Fig. 4] is a simplified and partial schematic top view, in perspective, of a refrigeration device according to another exemplary embodiment. Detailed description Throughout the figures, the same references relate to the same elements. In this detailed description, the following embodiments are examples. Although the description refers to one or more embodiments, this does not mean that the features apply only to a single embodiment. Individual features of different embodiments can also be combined and/or interchanged to provide other embodiments within the context of the claims. The low-temperature refrigeration device 1 illustrated is, for example, a cryogenic refrigerator, i.e. which produces cooling power by cooling/liquefying a working fluid at a temperature of between minus 100 degrees centigrade and minus 273 degrees centigrade. The refrigeration device 1 is preferably at least partly arranged (mounted) in and/or on a rigid support 100. The refrigeration device 1 comprises a working circuit 2 forming a loop and containing a working fluid (for example at least one of: helium, nitrogen, argon, neon, hydrogen). As also illustrated in [Fig. 3], the working circuit 2 comprises, arranged in series, a mechanism 3 for compressing the working fluid comprising at least one compressor, a mechanism 4, 7 for cooling the working fluid (one or more heat exchangers, for example), a mechanism for expanding the working fluid comprising at least one expansion turbine 6, and a mechanism 7 for heating the working fluid. The working circuit 2 is configured to subject the working fluid to a determined thermodynamic cycle in which the working fluid reaches at least a relatively low temperature at a cold end of the cycle. The compressors 3 are preferably driven in rotation by one or more electric motors 13 (for example mounted on the rotary shaft

12 of the motor 13). Preferably, at least some of the turbines 6 are also coupled to the same rotary shaft 12 driving one or more compressors 3 in order to restore mechanical work thereto (motor-turbocompressor). The device 1 comprises one or more refrigeration heat exchangers 7 intended to extract heat from at least one member 8 or fluid through heat exchange with the working fluid at the cold end of the cycle. As illustrated, the refrigeration heat exchanger 7 can ensure heat exchange between the working fluid after it has been expanded in the working circuit (before it is returned to the compression mechanism) and a user fluid 8 to be cooled. The one or more exchangers 7 can ensure that the working fluid in the cycle is simultaneously cooled and reheated via a countercurrent exchange. Typically, a fluid 8 to be cooled can be placed in thermal exchange with the working fluid at a plurality of temperature levels between the ambient temperature and the coldest temperature of the cold end of the cycle. The expansion mechanism comprises at least one expansion turbine 6 and preferably a plurality of expansion turbines 6. The device 1 comprises a cold box 9, i.e. a thermally insulated chamber (for example under vacuum) housing at least some of the cryogenic components of the working circuit 2 and in particular the refrigeration heat exchanger 7 and the at least one expansion turbine 6 and the corresponding parts of the working circuit 2. As illustrated, the cold box 9 has a cylindrical overall shape that extends, in the use configuration, preferably in a horizontal longitudinal direction about a central axis 10 of revolution. For example, the cold box 9 has a cylindrical body, preferably of circular cross section, the two longitudinal ends (or bottoms) of which are domed, for example of elliptical overall shape. At least one turbine 6 and, as illustrated, preferably a plurality of turbines 6 are mounted in the cold box 9 in the vicinity of a first longitudinal end of the cold box 9. In other words, the one or more turbines 6 are mounted longitudinally in the cold box 9 between the refrigeration heat exchanger 7 and the longitudinal end wall 11 of the cold box 9. As illustrated, the turbine 6 or plurality of turbines 6 are mounted so as to be transversely offset with respect to the central longitudinal axis 10 of the cold box 9. In other words, one or more turbines 6 are not mounted at the center of the end wall 11 along the central longitudinal axis 10 of revolution of the cold box 9 but so as to be transversely and/or vertically offset. This configuration makes it possible to install a plurality of turbines 6 on the same cold box 9, even relatively large turbines 6, while at the same time limiting the bulk of the device 1 (in particular the height and width). In the example of [Fig. 1], [Fig. 2] and [Fig. 3], the device 1 comprises, mounted on the same longitudinal end of the cold box 9, two turbines 6. The two turbines 6 are mounted on either side of the central longitudinal axis 10, for example halfway up the cold box 9 or in the upper part of the cold box. Of course, this example is in no way limiting, one or more turbines 6 could be mounted on the lower part of the end wall 11. Similarly, just one or more than two turbines 6 could be mounted on an end wall 11. For example, four turbines 6 may be mounted on the same end wall 11 (bottom). For example, two turbines 6 on the lower part of the wall 11 (below and on either side of the central longitudinal axis 10) and two turbines 6 on the upper part of the wall 11 (above and on either side of the central longitudinal axis 10). As shown schematically in [Fig. 4], turbines 6 may be mounted at the two longitudinal ends of the cold box 9. The device 1 may thus comprise four turbines 6 distributed two on each longitudinal side of the cold box 9. This makes it possible to increase the number of machines (turbines 6) of the device and/or makes it possible to reduce the mechanical stresses imposed on each of the two end walls 11. As illustrated, the turbines 6 may be mounted at the end of a shaft 12 of a motor 13 also driving a compressor of the compression mechanism 3. The motors 13 are situated outside the cold box 9 and preferably mounted on the structure of the support 100. These motors 13 may be connected to the rigid support by bolting. This makes it possible to take up forces, in particular without weakening the cold box 9 through which the turbines 6 are mounted as described below. As illustrated, the end of the shaft 12 bearing the turbine 6 may be mounted so as to pass through the end wall 11 of the cold box 9 in a fluid-tight manner via a tubular tapping connection 14 mounted so as to protrude on the outer surface of the longitudinal end wall 11 of the cold box 9. The tubular tapping connection 14 is thus off-center (not on the central longitudinal axis 10). The tubular connector 14 provides a mechanical connection (for example by welding) with the elliptical surface of the end wall 11. To this end, the thicknesses may be adapted locally and/or reinforcements may be provided for example at the connections 14. As illustrated, the working circuit 2 comprises at least one heat exchanger 4 and preferably a plurality of non-cryogenic heat exchangers 4 situated outside the cold box 9 and forming part of the mechanism 4, 7 for cooling the working fluid and/or of the mechanism 7 for heating the working fluid. The heat exchangers 4 have, for example, a planar or oblong overall shape and are mounted in and/or on the support 100, preferably in respective planes perpendicular to the longitudinal direction (central axis 10). At least some of these heat exchangers 4 can ensure thermal exchange between the working gas and a fluid 15, for example water, in order to ensure cooling after compression. A countercurrent exchanger 7 can also ensure heat exchange between two flows of working gas having different temperatures. This improves the compactness of the device 1 (optimization of the cost and of the footprint of the entire system). As shown schematically in [Fig. 4], the heat exchangers 4 situated outside the cold box 9 may be distributed on either side of the cold box 9 (in the longitudinal direction). As illustrated, the support 100 may be made up of a structure or frame 102 comprising beams assembled and mounted on legs 101. The support 100 may be an entity made up of a plurality of substructures assembled in the longitudinal direction. The motor assemblies 13 with turbines 6 may be arranged along the longitudinal axis, on the same structure or on a separate structure. The above-described structure has good mechanical strength and excellent compactness. This structure may in particular be modular (depending on the number of turbines 6 and/or heat exchangers 4 to be provided). A plurality of items of equipment may be installed in the same (vertical) plane. In addition, one or more structures supporting these elements may be provided on the support 100.

Claims

Claims

[Claim 1] A device for refrigeration and/or liquefaction at low temperature, i.e. at a temperature of between minus 100 degrees centigrade and minus 273 degrees centigrade, the refrigeration device (1) comprising a working circuit (2) forming a loop and containing a working fluid, the working circuit (2) comprising a mechanism (3) for compressing the working fluid comprising at least one compressor, a mechanism (4, 7) for cooling the working fluid, a mechanism (6) for expanding the working fluid comprising at least one expansion turbine (6), and a mechanism (7) for heating the working fluid, the working circuit (2) being configured to subject the working fluid to a determined thermodynamic cycle in which the working fluid reaches a relatively low temperature at a cold end of the cycle, the device (1) comprising a refrigeration heat exchanger (7) intended to extract heat from at least one member or fluid (8) through heat exchange with the working fluid, the device comprising a thermally insulated cold box (9) housing the refrigeration heat exchanger (7) and the at least one expansion turbine (6), the cold box (9) having a cylindrical overall shape extending in a longitudinal direction about a central axis (10), said axis (10) being horizontal in the use configuration, the at least one turbine (6) being arranged in the cold box (9) in the vicinity of a first longitudinal end of the cold box (9), the at least one turbine (6) being mounted longitudinally in the cold box (9) between the refrigeration heat exchanger (7) and the longitudinal end wall (11) of the cold box (9), characterized in that the at least one turbine (6) is mounted so as to be transversely offset with respect to the central longitudinal axis (10) of the cold box (9) and in that the at least one turbine (6) is mounted at the end of a shaft (12) of a motor (13) also driving a compressor of the compression mechanism (3), the motor (13) being situated outside the cold box (9), the end of the shaft (12) bearing the turbine (6) being mounted so as to pass through the end wall (11) of the cold box (9) in a fluid-tight manner and in that the longitudinal end wall (11) of the cold box (9) has a shape that is domed toward the outside of the cold box (9).
[Claim 2] The device as claimed in claim 1, characterized in that the end of the shaft (12) bearing the turbine (6) is mounted so as to pass through the end wall (11) of the cold box (9) in a fluid-tight manner via a tubular tapping connection (14) mounted so as to protrude on the outer surface of the longitudinal end wall (11) of the cold box (9).
[Claim 3] The device as claimed in either one of claims 1 and 2, characterized in that it comprises at least one additional turbine (6) arranged in the cold box (9) in the vicinity of a second longitudinal end of the cold box (9), the at least one additional turbine (6) being mounted longitudinally in the cold box (9) between the refrigeration heat exchanger (7) and the end wall of the second longitudinal end of the cold box (9), so as to be transversely offset with respect to the central longitudinal axis (10) of the cold box.
[Claim 4] The device as claimed in any one of claims 1 to 3, characterized in that it is arranged in and/or on a support (100).
[Claim 5] The device as claimed in claim 4, characterized in that the working circuit (2) comprises at least one heat exchanger (4) situated outside the cold box (9) and forming part of the mechanism (4) for cooling the working fluid, said at least one heat exchanger (4) being mounted in and/or on the support (100) in a plane perpendicular to the longitudinal direction (10).
[Claim 6] The device as claimed in claim 3 or 5, characterized in that it comprises a plurality of heat exchangers (4) situated outside the cold box (9) and forming part of the mechanism (4) for cooling the working fluid, said heat exchangers (4) being mounted in and/or on the support (100) in respective planes perpendicular to the longitudinal direction (10).
[Claim 7] The device as claimed in any one of claims 4 to 6, characterized in that the support (100) comprises at least one of: a set of one or more legs (102) for supporting the cold box (13), a frame (102).
[Claim 8] The device as claimed in any one of claims 4 to 7, characterized in that the support (100) is made up of a plurality of structures assembled in the longitudinal direction.

WO2024/074263 WO 2024/074263 1/2 1/2 PCT/EP2023/074734 PCT/EP2023/074734

[Fig. 1]

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WO2024/074263 WO 2024/074263 2/2 2/2 PCT/EP2023/074734 PCT/EP2023/074734

[Fig. 3]

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