Gas storage and / or transport tank including a protrusion.

Abstract

Gas storage and / or transport tank including a protrusion.The invention relates to a tank (1) for the transport and / or storage of a first gas, comprising a wall (2) delimiting a compartment (3) having a lower volume (4) intended to contain the first gas in liquid form and an upper volume (5) intended to contain the first gas in gaseous form, the wall (2) having an upper portion (9) contributing to delimiting the upper volume (5) of the compartment (3), characterized in that said tank (1) comprises a protrusion (16) positioned outside the compartment (3) and provided with a partition (17) delimiting an internal space (18), the upper portion (9) of the wall (2) comprising an opening (19) leading on the one hand into the upper volume (5) of the compartment (3) and on the other hand into the internal space (18) of the protrusion (16), the internal space (18) of the protrusion (16) containing at least in part a liquefaction device (20) for the first gas containing a second gas different from the first gas. (Figure 1).

Description

Title of the invention: Gas storage and / or transport tank comprising a protrusion.

[0001] The present invention relates to the field of transport and storage of a liquefied gas, for example hydrogen. It relates more particularly to installations for a sealed and thermally insulated tank for the storage and / or transport of the liquefied gas.

[0002] The liquefied gas is transported by sea in sealed, thermally insulated storage tanks installed on transport vessels. The gas is kept in liquid form to increase the quantity of gas transported per tank, as the volume occupied by one kilogram of gas in liquid form is much smaller than the volume occupied by one kilogram of gas in gaseous form. These tanks maintain the liquefied gas at very low temperatures, and more specifically for hydrogen, at a temperature below -250°C, the temperature at which hydrogen is in liquid form at atmospheric pressure.

[0003] The tank has a sealed wall that delimits the liquefied gas storage volume. This wall is subject to a heat flux that tends to warm the tank's contents, resulting in the evaporation of the liquefied gas. The tank is said to be thermally insulating insofar as the structure of the sealed wall is configured to minimize this heat flux and the vaporization of the liquefied gas.

[0004] The liquefied gas is thus present in the tank in a two-phase liquid-vapor equilibrium state. Part of the liquefied gas is in the vapor phase, thus forming a boiled-off gas (BOG) in an upper part of the tank volume, the liquefied gas being mainly in the liquid phase, this liquid phase extending into a lower part of the tank volume.

[0005] It is desirable to minimize the presence of evaporation gas in the storage tank. Several systems are therefore designed to condense this evaporation gas. Reliquefaction systems, for example, draw the evaporation gas out of the tank, cool it using heat exchangers external to the tank, and then reintroduce it into the tank. This process requires a significant amount of energy, as the evaporation gas heats up as it leaves the tank.

[0006] There are also subcooling systems that work by recovering liquid gas from the tank, subcooling it, and then spraying it onto the evaporation gas inside the tank to cool and liquefy this evaporation gas. For example, the liquefied gas in liquid phase is pumped from the bottom of the tank, The gas is subcooled outside the tank and then directed to spray nozzles located against the upper wall, which spray it into the upper part of the tank where the evaporation gas resides. This system also requires high energy consumption because, during the extraction of the liquid gas by the pumps, a significant amount of heat is injected into the liquid gas, necessitating a greater subcooling effort.

[0007] The invention falls within this context and aims to offer an alternative to these systems by presenting a tank comprising a housing for the transport and / or storage of a gas. This tank is equipped with a protrusion positioned outside the tank housing and in fluidic communication with said housing. The protrusion notably contains a liquefaction device enabling the gas located in the upper part of the tank to be liquefied in gaseous form, while consuming less energy than the traditional systems described in the prior art.

[0008] The present invention thus has as its main object a tank for the transport and / or storage of a first gas, comprising a wall delimiting a compartment whose lower volume is intended to contain the first gas in liquid form and whose upper volume is intended to contain the first gas in gaseous form, the wall having an upper part participating in delimiting the upper volume of the compartment, characterized in that said tank includes a protrusion positioned outside the compartment and provided with a partition delimiting an internal space, the upper part of the wall comprising an opening leading on the one hand into the upper volume of the compartment and on the other hand into the internal space of the protrusion, the internal space of the protrusion containing at least in part a device for liquefying the first gas containing a second gas different from the first gas.

[0009] The first gas transported and / or stored in the tank is typically a gas with a very low boiling point, often at temperatures expressed in negative degrees Celsius, such as dihydrogen. During transport and / or storage, this first gas is predominantly in liquid form within the tank. However, heat transfer occurs through the tank wall, which can warm the first gas and lead to its partial vaporization.

[0010] It should therefore be noted that inside the tank housing, the first gas exists in both liquid and gaseous form. The first gas in liquid form, due to gravity, remains at the bottom of the housing, referred to as the lower volume of the housing, while the first gas in gaseous form occupies the top of the tank, designated as the upper volume of the housing.

[0011] It is understood that, depending on the quantity of gas in gaseous and liquid form, the lower and upper volumes fluctuate. As will become apparent from the description of the invention, the objective is to control the rise in The tank pressure must not rise to a high pressure (typically a maximum pressure of around 2 bar) due to reliquefaction of the evaporated gas or its consumption, while simultaneously limiting the energy consumption associated with managing the evaporated gas, i.e., the gas in its gaseous form. In other words, the invention aims to enable the delivery of a maximum amount of gas in liquid form while ensuring minimal energy consumption for processing the gas in its gaseous state.

[0012] When the tank has the shape of a rectangular parallelepiped, the tank wall comprises an upper partition, an opposing lower partition, and lateral partitions connecting the lower partition to the upper partition. It is thus understood that, depending on the upper volume of the housing, the upper part of the wall comprises the upper partition and a more or less substantial upper portion of the lateral partitions. The same reasoning applies to a prismatic tank.

[0013] The upper part of the wall comprises an internal surface in contact with the first gas in gaseous form and delimiting the upper volume of the housing. It also comprises an external surface opposite the internal surface and at least partially in contact with the environment outside the tank. The protrusion is located on this external surface; therefore, the protrusion is outside the tank housing.

[0014] The protrusion is arranged to encircle the opening in the upper part of the wall. More precisely, its partition covers the opening, thus allowing communication between the internal space of the protrusion and the tank housing via this opening. As a result, the first gas in gaseous form can pass from the upper volume of the housing to the internal space of the protrusion.

[0015] The liquefaction device, located in the internal space of the protrusion, contains a second gas whose boiling point is lower than or equal to that of the first gas. For example, when the first gas is dihydrogen, the second gas could be helium, the normal boiling point of dihydrogen being -252.8°C and the boiling point of helium being -268.9°C. In this example, the liquefaction temperature of dihydrogen being between -250.24°C and -252.83°C, the temperature of the cold source can be between -252°C and -259°C, preferably between -255°C and -259°C.

[0016] This liquefaction device is designed to cool and liquefy the first gas in its gaseous form within the internal space of the protrusion in order to convert it into a liquid first gas. Once liquefied, the gas can return by gravity to the tank housing through the opening or through another opening provided for this purpose. The protrusion allows the first gas liquefaction operation to be located outside the tank, which, for example, makes it possible to operate the heat exchange means allowing this liquefaction less exposed to the movements of the first gas in liquid form within the tank, while offering a location protected from the outside to prevent the means of heat exchange from being too sensitive to ambient temperatures, which thus helps to limit the energy consumption related to the management of first gas in gaseous form within the tank.

[0017] According to an optional feature of the invention, the liquefaction device includes a heat exchange surface disposed within the internal space of the protuberance.

[0018] This heat exchange surface allows heat exchange between the first gas and the second gas and therefore constitutes the part of the liquefaction device which allows the liquefaction of the first gas.

[0019] The heat exchange surface is thus positioned within the internal space of the protrusion, enabling heat exchange when the first gas, in its gaseous form, occupies this internal space. Upon contact with the heat exchange surface, the first gas can transfer heat. Having released heat, the first gas liquefies and can fall by gravity into the internal space of the protrusion before being expelled and falling back into the tank housing. To be expelled from the internal space of the protrusion, the first gas can be guided by a collector leading it to the opening or another opening provided for this purpose. The collector can, for example, consist of an inclined plane.

[0020] According to an optional feature of the invention, the liquefaction device includes a second gas circulation conduit, the heat exchange surface being at least partly defined by an external peripheral surface of the circulation conduit.

[0021] The external peripheral surface is a surface opposite an internal zone of the circulation conduit, this internal zone, or peripheral surface, of the conduit being the surface of the circulation conduit in contact with the second gas which circulates within this circulation conduit.

[0022] The external peripheral surface is in contact with the first gas in gaseous form present in the internal space of the protuberance.

[0023] Thus, when the first gas is in contact with the outer peripheral surface and the second gas is in contact with the inner zone, heat transfer occurs between the first and second gases via these surfaces. The second gas then absorbs heat, tends to evaporate, and subsequently circulates through the liquefaction device, while the first gas liquefies.

[0024] According to an optional feature of the invention, the external peripheral surface of the circulation conduit is between 20 and 100 m2.

[0025] These external peripheral surface area values ​​allow for efficient cooling and liquefaction of the first gas for a given flow rate of evaporated gas generated by the heat inputs into the tank. By way of non-limiting example, an external peripheral surface area of ​​the circulation line between 20 m² and 100 m² is particularly effective for liquefying 90 kg / h of evaporated gas.

[0026] To increase the heat exchange surface area between the first and second gases, the circulation duct can be designed with sinuous or spiral shapes. This increases the external peripheral surface area of ​​the circulation duct within the internal space of the protrusion, thereby improving the liquefaction of the first gas. Alternatively or in addition, the heat exchange surface area between the first and second gases can be increased by internal or external fins arranged at the heat exchange surface.

[0027] According to an optional feature of the invention, the opening forms a unique means of communication between the internal space of the protrusion and the housing of the tank.

[0028] In other words, the opening allows the first gas, in its gaseous form, to pass in one direction from the upper volume of the housing to the internal space of the protrusion, and in the other direction, the first gas, in its liquid form following liquefaction within the protrusion, to pass from the internal space of the protrusion back to the upper volume of the housing. Thus, the first gas, once liquefied by the liquefaction device, can pass through the same opening through which it previously passed in its gaseous state. This simplifies the configuration of the protrusion, as only one opening is required for these exchanges.

[0029] Optionally, the opening includes a tube, said tube protruding into the internal space of the protrusion. In this case, the first gas liquefied by the liquefaction device passes through the space formed between the opening and said tube. The first gas in gaseous form from the tank housing is then not impeded by the flow of the first liquefied gas.

[0030] In an alternative of the invention, the first gas liquefied by the liquefaction device is evacuated from the internal space of the protuberance through a passage in the upper part other than the opening.

[0031] According to an optional feature of the invention, the protrusion includes a conduit for the evacuation of the first gas passing through the partition of the protrusion.

[0032] This evacuation conduit allows the evacuation of excess first gas from the internal space of the protrusion to be managed, thus helping to maintain a certain pressure within the tank.

[0033] The first gas discharged through this discharge pipe can then be used for other applications. It can, for example, be burned to recover energy. or for other industrial processes, for example to power the ship's propulsion engines or electric generators.

[0034] According to an optional feature of the invention, the tank includes a vacuum bell covering the protrusion and hermetically connected to the upper part of the wall.

[0035] The vacuum bell, by covering the protrusion, helps to prevent heat transfer between the environment outside the tank and the internal space of the protrusion and prevents the liquefaction of oxygen from the ambient air.

[0036] This prevents the protrusion from heating up, thereby reducing the amount of energy required to cool and liquefy the second gas. Consequently, the presence of the vacuum bell improves the efficiency of the liquefaction device.

[0037] According to an optional feature of the invention, the vacuum bell is welded to the upper part of the wall.

[0038] This weld ensures a seal between the vacuum bell and the wall. In other words, this weld prevents exchanges between the interior and exterior spaces of the bell, thus isolating the protrusion from the external environment.

[0039] The vacuum bell can be equipped with means reinforcing the weld, such as a welding collar.

[0040] This welding collar thus reinforces the joint of the vacuum bell to the upper part of the wall.

[0041] According to an optional feature of the invention, the drain pipe passes through the vacuum bell.

[0042] When a vacuum bell is used, the drain pipe passes through the bulkhead of the protrusion and through the vacuum bell. This configuration allows excess of the first gas to be evacuated and excessive pressure to be regulated within the protrusion, even when a vacuum chamber covers the protrusion.

[0043] According to an alternative of the invention, the liquefaction device is integrated at least partially into the partition of the protuberance.

[0044] According to an optional feature of the invention, the liquefaction device includes a means for cooling the second gas, the cooling means being positioned outside the protrusion.

[0045] The cooling means may, for example, be part of a refrigeration cycle for the second gas. In the case of a reverse Brayton cycle, the cooling means may, for example, include an expansion valve, a compressor, and piping.

[0046] According to an alternative of the invention, the cooling means is integrated at least partially into the partition of the protrusion.

[0047] According to an optional feature, the liquefaction device includes an additional heat exchanger disposed within the internal space of the protuberance.

[0048] According to an optional feature of the invention, the opening and the discharge conduit are aligned so as to form a circulation path for the first gas within the protrusion.

[0049] In this case, the liquefaction device is arranged away from this traffic lane, for example in an annular manner around said lane.

[0050] It should be noted that the protrusion allows the implementation of three modes of operation including a BOG subtraction mode in which the entire first gas passing through the protrusion is evacuated through the evacuation line, a liquefaction mode in which the entire first gas is liquefied and a hybrid mode in which part of the first gas is liquefied by the liquefaction device and another part is evacuated through the evacuation line.

[0051] The traffic path corresponds to the path of the first gas when the protuberance is in BOG subtraction mode.

[0052] When the protrusion is in hybrid mode or liquefaction mode, all or part of the first gas is diverted from the gas flow path by cryopumping the first gas by the liquefaction device.

[0053] According to an optional feature of the invention, the upper part of the wall comprises a gas dome having a passage defining a path for the evacuation of the first gas in vapor form, the internal space of the protrusion being configured so that the heat exchange surface of the liquefaction device is positioned away from the path for the evacuation of the first gas.

[0054] The gas dome can also be equipped with a tube which serves to transfer the first gas, in liquid form, to or from the tank housing.

[0055] By defining an escape route for the first gas in vapor form, the passage facilitates the evacuation of this first gas in the event of overpressure in the tank housing. It should be understood that the escape route for the first gas corresponds to the path the gas follows when it is evacuated through the passage.

[0056] Regarding the arrangement of the protrusion, it can be positioned to cover the gas dome passage; in this case, the opening in the upper part of the wall coincides with the passage. Thus, the first gas exhaust path extends between the exhaust pipe and this passage, corresponding to the first gas flow path within the protrusion. The heat exchange surface of the The liquefaction device is then positioned so as not to obstruct this evacuation route.

[0057] The protrusion can also be installed away from the gas dome. If this is the case, the passage and the opening are two separate openings. The arrangement of the protrusion thus ensures that the liquefaction device is positioned away from the gas discharge path.

[0058] According to an optional feature of the invention, the protrusion is welded to the upper part of the wall. The weld then makes it possible to connect the partition of the protrusion to the upper part of the wall in a hermetic manner.

[0059] According to an optional feature of the invention, the protrusion includes a welding collar. The welding collar thus reinforces the weld of the protrusion to the upper part of the wall.

[0060] According to an optional feature of the invention, the first gas evacuation duct and the second gas circulation duct pass through the protrusion partition on the same portion of the partition.

[0061] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and the illustrative and non-limiting examples of embodiments given with reference to the accompanying drawings on the other hand, in which:

[0062] [Fig-1] is a cross-sectional view of a tank used for the transport and / or storage of a first gas and comprising a first embodiment of a protuberance.

[0063] [Fig.2] is a cross-sectional view of the protuberance according to the first embodiment.

[0064] [Fig.3] is a cross-sectional view of a second embodiment of the protuberance.

[0065] [Fig.4] is a cross-sectional view of a third embodiment of the protuberance.

[0066] [Fig.5] is a cross-sectional view of a fourth embodiment of the protuberance.

[0067] [Fig.6] is a cross-sectional view of a fifth embodiment of the protuberance

[0068] The features and variants of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of the features described below, isolated from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0069] In the figures, the elements common to several figures retain the same reference.

[0070] Fig. 1 is a cross-sectional view of a tank 1 used for the transport and / or storage of a first gas and comprising a first embodiment of a protuberance 16.

[0071] The first gas can be of any type that exists in gaseous and liquid forms. Dihydrogen is particularly used as the first gas, although other applications of the tank with, for example, liquefied natural gas are also conceivable.

[0072] The tank 1 includes a wall 2 which delimits a compartment 3. It should be understood that the compartment 3 corresponds to an internal void space within the tank 1, intended to contain the first gas. The wall 2 therefore serves to form this internal void space by delimiting the compartment 3.

[0073] Within this housing 3, the first gas can be present in different states. It is originally stored in the tank 1 in liquid form, but due to a heat flow at the wall 2 which tends to cause the evaporation of the first gas, the first gas is present in housing 3 in both liquid and gaseous form.

[0074] Housing 3 comprises a lower volume 4, where the first gas is in liquid form, and an upper volume 5, where the first gas is in gaseous form. Indeed, under the effect of gravity, the first gas in liquid form naturally remains in the lower volume 4, which can be considered the lower part of housing 3. At the same time, the first gas in gaseous form will occupy the part of housing 3 not filled by the liquid gas and therefore naturally remains in the upper volume 5, which can be considered the upper part of tank 1.

[0075] The dimensions, and in particular the height of each volume, vary according to the quantity of first gas in liquid form and therefore the complementary quantity of first gas in vapor form.

[0076] Within the wall, an upper part 9 and a lower part 10 can be distinguished, separated from each other by the liquid gas flotation surface. More specifically, the wall 2 comprises an upper partition 6, a bottom partition 7, and side partitions 8. The bottom partition 7, located opposite the upper partition 6, forms the floor of the tank 1. The upper partition 6 forms the ceiling of the tank 1. The side partitions 8 connect the upper partition 6 to the bottom partition 7. Thus, when the tank 1 is placed on a flat, horizontal surface, the bottom partition 7 and the upper partition 6 are substantially horizontal, while the side partitions 8 are substantially vertical.

[0077] It should therefore be understood that the upper part 9 of the wall 2 comprises the upper partition 6 and an upper part of the side partitions 8, in contact with the first gas in gaseous form. Similarly, the lower part 10 of the wall 2 comprises the bottom partition 7 and another part of the side partitions 8, the bottom partition 7 and this other part of the side partitions 8 being in contact with the first gas in liquid form.

[0078] The wall 2 of the tank 1 comprises an internal surface 11 and an external surface 12. The internal surface 11 is the one that delimits the housing 3; it is thus located inside the tank 1. The external surface 12 is the one that delimits the exterior of the tank 1 and is therefore in contact with a medium external to the tank 1. It should therefore be understood that the upper part 9 and the lower part 10 of the wall 2 each comprise a part of the internal surface 11 and a part of the external surface 12. Thus, the upper part 9 of the wall 2 is in contact with the first gas, when it is in the gaseous phase, via the internal surface 11, and the lower part 10 is also in contact with the first gas, when it is in liquid form, via the internal surface 11.

[0079] The tank 1 is equipped with a gas dome 13 located in the upper part 9 of the wall 2 of the tank 1, more precisely in the ceiling 6 of the wall 2. This gas dome 13 contains a passage 15 allowing the first gas to be evacuated in gaseous form from the housing 3 of the tank 1. The gas dome 13 also includes a pipe 14 allowing the supply or evacuation of the first gas in liquid form from the housing 3 of the tank 1. This pipe 14 extends from the outside of the tank 1 towards the lower volume 4 of the housing 3 by passing through the gas dome 13.

[0080] The tank 1 according to the invention comprises a protrusion 16, which is disposed in contact with the external surface 12 of the upper part 9. The protrusion 16 is therefore not located inside the housing 3 but outside of it. Since it is positioned on the external surface 12 of the upper part 9, the protrusion 16 can be located either on the upper partition 6 or on the upper portion of the side partitions 8 in contact with the first gas in gaseous form. In the embodiment illustrated in [Fig. 1], the protrusion 16 is disposed on the upper partition 6.

[0081] The protrusion 16 is hollow and includes a partition 17 that defines an internal space 18. The internal space 18 of the protrusion 16 is in fluidic communication with the housing 3 of the tank 1. For this purpose, the upper part 9 includes an opening 19, the partition 17 of the protrusion 16 being arranged so that the protrusion 16 covers this opening 19. By "fluidic communication," it should be understood that the first gas can flow between the upper volume 5 of the housing 3 of the tank 1 and the internal space 18 of the protrusion 16 (in gaseous form) and between the internal space 18 of the protrusion 16 and the housing 3 of the tank 1 (in liquid form). Further details will be provided in the description of the following figures.

[0082] The tank 1 also includes a liquefaction device 20 for the first gas, which is positioned at least partially within the internal space 18 of the protrusion 16. The role of this liquefaction device 20 is to liquefy the first gas in the form gaseous present in the internal space 18 of the protuberance 16, so that it becomes liquid again and takes position, by gravity, in the lower volume 4 of the housing 3 by passing through the opening 19.

[0083] Liquefaction is carried out by heat exchange with the portion of the liquefaction device 20 which is present in the internal space 18 of the protuberance 16, that is to say the portion of the device 20 which is in direct contact with the first gas in vapor form.

[0084] Fig. 2 is a cross-sectional view of protuberance 16 according to the first embodiment.

[0085] In this embodiment, the protrusion 16 is in the shape of a parallelepiped. The partition 17 of the protrusion 16 thus comprises an upper panel 21, a lower panel 37, and side panels 22. When the tank 1 is positioned on a flat, horizontal surface, the upper panel 21 is horizontal and the side panels 22 are arranged vertically. The upper panel 21 and the lower panel 37 constitute the upper and lower faces, respectively, while the side panels 22 form the lateral faces of the parallelepiped.

[0086] It should be noted that this configuration of the protuberance 16 is not limiting and that other forms are also conceivable, for example a cylindrical protuberance comprising at least a part of the liquefaction device 20 arranged in an annular manner in said protuberance.

[0087] The side panels 22 are in contact with the external surface 12 of the upper part 9 of the wall 2. These side panels 22 are arranged all around the opening 19 so that the entire partition 17 of the protrusion 16 surrounds said opening 19.

[0088] To ensure a secure attachment, these side panels 22 can be welded to the external surface 12 and fitted with flanges 23 forming a base for the side panels 22 and reinforcing the weld strength with the wall 2. However, the protrusion is not necessarily fixed or welded to the upper part 9 of the wall 2. Only a fluid connection between the protrusion and the tank is required. For example, the protrusion can be arranged around a circulation channel extending hermetically from the opening 19 without forming physical contact with the upper part 9 of the wall 2. Indeed, the function of the protrusion is to protect the liquefaction device 20 from sloshing (charge sloshing) in the tank while ensuring vapor circulation and liquid return to the tank without an additional circulation system (such as a compressor or pump).The lower panel 37 includes an opening 38 positioned to correspond to the opening 19 of the upper part 9 of the wall 2, thus forming a common passage from the internal space 18 of the protrusion 16 to the upper volume 5 of the housing 3 of the tank 1. .

[0089] In this embodiment, the protrusion 16 is covered by a vacuum bell 25. The vacuum bell 25 comprises an upper enclosure wall 261 and side enclosure walls 262 including collars 263 by which said bell 25 is brought into contact with the external surface 12 of the upper part 9 of the wall 2. These side enclosure walls 262 are arranged parallel to and at a distance from the side panels 22 of the partition 17 of the protrusion 16, and the upper enclosure wall 261 is arranged parallel to and at a distance from the upper panel 21 of the partition 17 of the vacuum bell. In this way, the vacuum bell 25 covers the protrusion 16.

[0090] The vacuum bell 25 is hermetically sealed to the upper part 9 of the wall 2 by means of a welding of its collars 263 to the external surface 12 of the upper part 9.

[0091] The vacuum bell 25 thus delimits a vacuum space around the protuberance 16, thereby isolating it from the external environment and allowing a more efficient liquefaction of the first gas by preventing the ambient air from heating the side panels 22 and the upper panel 21 of the partition 17.

[0092] The protrusion 16 includes a first gas discharge conduit 27, allowing the first gas not liquefied by the liquefaction device 20 to escape from the internal space 18 of the protrusion 16. This first gas can then be used for various applications.

[0093] The evacuation pipe 27 is positioned so as to pass through the upper panel 21 of the partition 17 of the protrusion 16 and the upper enclosure wall 261 of the vacuum bell 25, in order to allow the evacuation of the first gas in gaseous form beyond the vacuum bell.

[0094] The liquefaction device 20 includes a circulation conduit 28 for a second gas. This second gas is preferably a gas having a lower liquefaction point than that of the first gas, for example helium when the first gas is dihydrogen.

[0095] Thanks to the circulation of the second gas within the liquefaction device 20, the circulation conduit 28 of the liquefaction device 20 contributes to forming a heat exchange surface 29 between the first gas and the second gas. It is thus understood that the heat exchange surface 29 is composed of the parts of the liquefaction device 20 that are arranged in the internal space 18 of the protrusion 16.

[0096] The circulation conduit 28 is partially disposed within the internal space 18 of the protrusion 16. The remainder of the liquefaction device 20 is positioned outside the internal space 18 of the protrusion 16. Since the circulation conduit 28 is, in this embodiment, the only part of the liquefaction device 20 disposed within the internal space 18 of the protuberance 16, it should be understood that the circulation duct 28 alone forms the heat exchange surface 29.

[0097] More specifically, the circulation pipe 28 has a cylindrical shape and thus comprises an external peripheral surface opposite an internal peripheral surface. The external peripheral surface is in contact with the first gas, while the internal peripheral surface is in contact with the second gas circulating within the circulation pipe 28. The external peripheral surface and the internal peripheral surface cooperate to form the heat exchange surface 29 of the liquefaction device 20. In this way, the first gas transfers its heat to the external peripheral surface, and the heat is transferred to the internal peripheral surface, where it is transferred to the second gas. As a result of this heat transfer, the first gas liquefies, while the second gas absorbs heat, thereby increasing its temperature.

[0098] The circulation conduit 28 can adopt different shapes, such as a spiral shape, in order to increase its external peripheral surface area and its internal peripheral surface area within the internal space 18 of the protrusion 16. This shape increases the heat exchange surface area 29 of the liquefaction device 20 between the first gas and the second gas, thus allowing for more efficient liquefaction of the first gas. The circulation conduit 28 can also include internal and / or external fins to increase the heat exchange surface area between the first and second gases.

[0099] Preferably, the external peripheral surface area of ​​the circulation pipe 28 is between 20 and 100 m². It should be noted that these figures are given by way of non-limiting example. In this example, to liquefy 90 kg / h of BOG of dihydrogen at saturation at 1.1 bar, 11.2 kW of cooling is required. Taking helium as the second gas used in a Brayton cycle with 2 bar at low pressure (-259°C at the tank inlet) and a minimum pinch-off of 2°C with the first gas to be liquefied (dihydrogen), the second gas passing through circulation pipes with an external diameter of 20 mm made of stainless steel, 40 m² of heat exchange surface area is required.

[0100] Alternatively, the liquefaction device 20 may include a heat exchange surface disposed at the level of the partition 17 of the protrusion. In this case, the heat exchange surface is integrated into the partition of the protrusion.

[0101] The liquefaction device 20 includes a cooling means 31 for the second gas, which is part of a refrigeration cycle for the second gas. In this embodiment, the cooling means 31 for the second gas is positioned outside the protrusion 16 and also outside the vacuum bell 25. This cooling means 31 is connected to the circulation line 28 of the second gas gas. The cooling means 31 is shown schematically and, in the case of a reverse Brayton cycle, it may include, but is not limited to, an expansion valve, a compressor and piping.

[0102] The circulation line 28 thus passes through the vacuum bell 25 and the partition 17 of the protrusion 16, so as to be partially present in the internal space 18 of the protrusion 16 and able to cooperate with the cooling means outside the vacuum bell. More specifically, the circulation line 28 passes through two openings in the vacuum bell 25 and two openings in the partition 17 of the protrusion 16 in order to connect to the cooling means 31. In this embodiment, the circulation line 28 passes through the partition 17 of the protrusion 16 on its upper panel 21, that is to say, on the same portion of the partition 17 where the drain line 27 passes through said partition 17. Furthermore, the circulation line 28 passes through the vacuum bell 25 on its upper enclosure wall 261.

[0103] The protrusion 16 according to the invention allows for three operating modes, including a so-called "BOG subtraction" mode, a so-called liquefaction mode, and a so-called hybrid mode. In the "BOG subtraction" mode, all of the first gas passing through the protrusion 16 is discharged through the discharge pipe 27. In this mode, the liquefaction device 20 is not in operation. The first gas, in vapor form, then passes through the opening 19, then through the internal space 18, and is discharged through the discharge pipe 27 without being particularly cooled.

[0104] The liquefaction device 20 is activated if the hybrid mode or the liquefaction mode is implemented. In the hybrid mode, part of the first gas is liquefied by the liquefaction device 20 and another part is discharged through the discharge line 27. In the liquefaction mode, all of the first gas is liquefied.

[0105] It should be noted that the opening 19 in the upper part 9 of the wall 2 is aligned with the first gas discharge pipe 27. This arrangement then forms, when the protrusion 16 is in BOG subtraction mode, a flow path 35 for the first gas through the internal space 18 of the protrusion 16 which is direct, from the opening 19 to the discharge pipe 27. This flow path 35 therefore represents the way in which the first gas moves predominantly within the internal space 18 of the protrusion 16 when the protrusion 16 is in BOG subtraction mode.

[0106] In this embodiment, the protrusion 16 extends laterally with respect to this flow path 35 of the first gas. It is understood from this that the protrusion 16 extends predominantly in at least one direction perpendicular to the flow path 35 of the first gas. The liquefaction device 20, and more particularly the portion of the flow line 28 housed in the internal space 18, is thus positioned away from this flow path 35. It is understood that in the case where the protrusion 16 is cylindrical in shape, the opening 19 and the discharge pipe 27 can be centered on the axis of revolution of the protrusion and the portion of the circulation pipe 28 present in the internal space is disposed against the annular wall, so that this annular disposition places the portion of the circulation pipe 28 present in the internal space away from this circulation path 35.

[0107] Positioning the liquefaction device 20 away from the traffic lane 35 implies diverting the first gas to be liquefied when the device is in operation. In liquefaction mode or hybrid mode, the liquefaction device 20 is activated, which attracts the first gas in gaseous form by cryopumping and diverts it away from the traffic lane 35.

[0108] In hybrid mode, the flow rate of the second gas associated with the liquefaction device 20 is adjusted so as to attract only a fraction of the first gas by cryopumping and liquefy it upon contact with the portion of the circulation pipe 28 present in the internal volume 18. Thus, a fraction of the first gas is liquefied and a fraction of the first gas is discharged through the discharge pipe 27. The flow rate of the second gas is set between a first threshold value, below which the first gas is not diverted from the circulation path 35, and a second threshold value beyond which it must not go if only partial diversion of the first gas is desired. Indeed, the flow rate of the second gas determines the power of the system implemented and therefore the flow rate of the first liquefied gas.

[0109] It should be noted that for a given system power output, the temperature at which the second gas is operated defines the heat exchange surface area required to liquefy a certain flow rate of the first gas. As a non-limiting example, when the first gas is dihydrogen, its temperature will be below -251°C and advantageously between -252.8°C (the liquefaction temperature of dihydrogen at a pressure of 1 atm) and -259.2°C (the triple point of dihydrogen). It is worth noting that operating at a low temperature for the second fluid, i.e., relatively close to -259.2°C, avoids having to increase the flow rate of the second gas too significantly.

[0110] In the liquefaction mode, the entire first gas is diverted from the flow path 35 to the liquefaction device 20 to be liquefied, and for this purpose, the liquefaction device 20 has a flow rate beyond the second threshold value.

[0111] To aid the liquefaction of all the first gas, the discharge line 27 may include a blocking means preventing the first gas from escaping from the protrusion 16 through this line 27. This blocking means may be an on / off valve, i.e., in the open or closed position depending on the mode implemented. In the liquefaction mode, the blocking means is in the closed position. In the BOG subtraction mode, the blocking means is in the open position and it There is no second gas flow in the liquefaction unit. In hybrid mode, the blocking means is in the open position, and a Boil-Off Gas (BOG) compressor of the liquefaction unit 20 controls the flow rate drawn from the tank. In other words, in hybrid mode, the flow rate of the first liquefied gas is controlled by regulating the flow rate of the second gas in the liquefaction unit 20.

[0112] It is therefore understood that the mode of operation implemented by the protrusion 16, associated with the operation of the BOG compressor, is dictated by the flow rate of the second gas in the liquefaction device 20, as well as by the blocking means when the discharge line 27 includes one.

[0113] The lower panel 37 comprises a first face 39 in contact with the external surface 12 of the upper part 9 of the wall 2 and a second face 40 partially defining the internal space 18 of the protrusion 16. The first face 39 is horizontal when the tank 1 is positioned on a flat, horizontal surface. The second face 40, however, is inclined relative to the first face 39 and is therefore also inclined relative to the external surface 12 of the upper part 9 of the wall 2 when the tank 1 is placed on a flat, horizontal surface. It should be understood that the inclination of the second face 40 relative to the first face 39 is due to a variation in the thickness of the lower panel 37, the thickness of the lower panel 37 being greater at the junction of this lower panel 37 with the side panel 22 than at the opening 38.

[0114] The lower panel 37 allows, when the first gas is liquefied in the hybrid mode or in the liquefaction mode and the first gas in liquid form falls by gravity onto the lower panel 37, that this first gas in liquid form is directed by the inclination of the second face 40 of the lower panel 37 towards the common passage formed by the orifice 38 and the opening 19. This first gas, having become liquid again under the effect of the liquefaction device and flowing under the effect of gravity towards the orifice 38, is thus evacuated from the internal space 18 of the protuberance 16 by passing through the common passage before falling into the lower volume 4 of the housing 3 of the tank 1.

[0115] The orifice 38 can be delimited by a collar 41 which extends substantially perpendicularly from the lower panel 37 projecting from the first face 39, the collar 41 being intended to come into contact with a wall of the tank delimiting the opening 19. In this way, the first gas which flows by gravity into the common passage cannot pass between the lower panel 37 and the external surface 12 of the upper part 9 of the wall 2, thus avoiding sealing problems and potential losses of first gas.

[0116] Regarding the gas dome 13, its passage 15 defines an escape route 36 for the first gas. In this embodiment, the opening 19 in the upper part 9 of wall 2 and passage 15 of gas dome 13 are two distinct passages in wall 2. Since passage 15 delimits the evacuation path 36 of the first gas and opening 19 delimits the circulation path 35 of the first gas, it is understood that these are two distinct paths through which the first gas circulates.

[0117] Fig. 3 is a cross-sectional view of a second embodiment of protuberance 16.

[0118] In this embodiment, the protrusion 16 also includes a liquefaction device 20 positioned partly within its internal space 18. In addition, the liquefaction device 20 also includes a circulation conduit 28 which, by virtue of its external peripheral surface, forms part of the heat exchange surface 29 between the first gas and the second gas.

[0119] In this embodiment, the liquefaction device 20 includes an additional heat exchanger 34 shown schematically in this figure. This additional heat exchanger 34, through which the second gas also circulates, is located in the internal space 18 of the protrusion 16 and is connected to the cooling means 31.

[0120] Thanks to this feature, the heat exchange surface 29 of the liquefaction device 20 is no longer solely formed by the circulation pipe 28 as in the case of the second embodiment, but is composed of the circulation pipe 28 and the additional heat exchanger 34. Indeed, the additional heat exchanger participates in liquefying the first gas in the internal space 18, since it is in contact with this first gas.

[0121] The remaining features of this second embodiment are similar to the features of the first embodiment.

[0122] Fig. 4 is a cross-sectional view of a third embodiment of protuberance 16.

[0123] In this embodiment, a guide tube 42 is disposed within the opening 19. The guide tube 42 is a cylinder whose diameter is less than the diameter of the opening 19. This guide tube 42 extends in the opening 19 over the entire thickness of the upper part 9 of the wall 2, and protrudes into the internal space 18 of the protrusion 16.

[0124] It should be understood from the fact that the guide tube 42 protrudes into the internal space 18 that it extends between a first end, turned towards the tank and which may be flush with the internal surface 11 of the upper part 9 of the wall 2, and a second end, turned towards the protrusion and which extends beyond the second face 40 of the lower panel 37 of the protrusion. In this way, the first gas in gaseous form, brought up into the protrusion, passes mainly inside the guide tube 42, while the first gas, Having returned to liquid form following liquefaction in the protuberance, it flows along the walls delimiting the opening 19. It is therefore understood that the first liquefied gas flows by gravity into the opening 19 around the guide tube 42, which prevents the return by gravity of the first gas in liquid form from disturbing the path of the first gas in gaseous form passing from the upper volume 5 to the internal space 18 of the protuberance 16.

[0125] The remaining features of this third embodiment are similar to the features of the first embodiment.

[0126] Fig. 5 is a cross-sectional view of a fourth embodiment of protuberance 16.

[0127] In this embodiment, the protuberance 16, in addition to being arranged to cover the opening 19, is arranged to cover a hole 43 passing through the upper part 9 of the wall 2 in a manner distinct from the opening 19.

[0128] The through hole 43 allows fluidic communication between the internal space 18 of the protrusion 16 and the upper volume 5 of the housing 3. For this purpose the lower panel 37 of the protrusion 16 includes, in addition to the orifice 38 allowing to form a common passage with the opening 19, a complementary hole 44 forming, with the through hole 43, another common passage from the internal space 18 to the upper volume 5.

[0129] The additional hole 44 and the through hole 43 are here arranged substantially below the liquefaction device 20, so that when the first gas is liquefied, it falls back by gravity towards the common passage formed by the additional hole 44 and the through hole 43. It is therefore understood that these two holes 44, 43 are used essentially to drain the first liquefied gas from the internal space 18 to the housing 3, while the orifice 38 and the opening 19 are used to supply the protrusion 16 with the first gas in gaseous form from the housing 3.

[0130] The common passage formed by the complementary hole 44 and the through hole 43 has a diameter that is substantially smaller than the diameter of the common passage formed by the opening 19 and the orifice 38. In this way, the upward flow of gas through the through hole 43 of the first gas in gaseous form is limited, thus preventing disturbance of the first liquefied gas flowing through it. Furthermore, the large diameter of the common passage formed by the opening 19 and the orifice 38 limits the pressure drop of the first gas in gaseous form as it passes from the housing 3 to the internal space 18.

[0131] Alternatively, the additional hole 44 and / or the through hole 43 can be equipped with a liquid guard with a siphon to prevent the first gas in gaseous form from passing from the housing 3 to the internal space 18 through these holes 44, 43.

[0132] The presence of this additional passage, formed by the complementarity of the through hole 43 and the complementary hole 44, can be particularly useful when, alternatively, the supply of the protrusion 16 with the first gas in gaseous form from the housing 3 is provided by a supply system arranged on one of the side panels 22 and replacing the function of the opening 19 and the orifice 38. In this context, the evacuation by gravity of the first gas which has become liquid again under the effect of liquefaction is made possible by the presence of the additional passage.

[0133] Unlike the lower panel 37 of the first embodiment, which guides the first liquefied gas towards the orifice 38, the lower panel 37 of this embodiment here has a funnel shape which allows the first liquefied gas falling by gravity from the liquefaction device 20 to be guided to the common passage formed by the complementary hole 44 and the through hole 43.

[0134] The remaining features of this fourth embodiment are similar to the features of the first embodiment.

[0135] Fig. 6 is a cross-sectional view of a fifth embodiment of protuberance 16.

[0136] In this embodiment, the protrusion 16 is positioned partly above the gas dome 13. The passage 15 of the gas dome 13 then coincides with the opening 19 of the upper part 9 of the wall 2. The first gas 36 exhaust path thus coincides with the gas circulation path 35 within the internal space 18 of the protrusion 16. Consequently, the first gas 36 exhaust path extends here from the opening 19 of the upper part 9 of the wall 2 to the exhaust duct 27 of the protrusion 16.

[0137] It should therefore be noted that in this case, the protrusion 16 extends laterally with respect to the first gas evacuation route 36. It is thus understood that the protrusion 16 extends in a direction perpendicular to the evacuation route 36 on at least one side.

[0138] The liquefaction device 20 is positioned away from the evacuation path 36. It should be understood by this that the liquefaction device 20 is positioned so as not to be across the gas evacuation path 36, in accordance with what has been described for the first embodiment with respect to the gas circulation path 35.

[0139] The remaining features of this fifth embodiment are similar to the features of the first embodiment.

[0140] As described above, through several embodiments, the present invention achieves its objectives, namely to optimize the presence of gas in liquid form within a tank, by proposing a tank designed to contain a first gas and equipped with a protrusion comprising a device for liquefying the first gas. The use of this protrusion optimizes the liquefaction process of the first gas, which is in a gaseous state in the upper part of the tank. The major advantage of this invention is that it allows the gas to be liquefied while consuming significantly less energy than traditional systems described in the prior art.

[0141] The present invention is not limited to the means and configurations described and illustrated herein and extends also to any equivalent means and configuration as well as to any technically operative combination of such means.

Claims

Demands

1. A tank (1) for the transport and / or storage of a first gas, comprising a wall (2) delimiting a compartment (3) having a lower volume (4) intended to contain the first gas in liquid form and an upper volume (5) intended to contain the first gas in gaseous form, the wall (2) having an upper portion (9) contributing to the delimitation of the upper volume (5) of the compartment (3), characterized in that said tank (1) comprises a protrusion (16) positioned outside the compartment (3) and provided with a partition (17) delimiting an internal space (18), the upper portion (9) of the wall (2) comprising an opening (19) leading on the one hand into the upper volume (5) of the compartment (3) and on the other hand into the internal space (18) of the protrusion (16), the internal space (18) of the protrusion (16) containing at least in part a liquefaction device (20) of the first gas containing a second gas different from the first gas.

2. Tank (1) according to claim 1, in which the liquefaction device (20) comprises a heat exchange surface (29) disposed within the internal space (18) of the protrusion (16).

3. Tank (1) according to claim 2, in which the liquefaction device (20) comprises a circulation conduit (28) for the second gas, the heat exchange surface (29) being at least partly defined by an external peripheral surface of the circulation conduit (28).

4. Tank (1) according to claim 3, in which the external peripheral surface of the circulation pipe (28) is between 20 and 100 m2.

5. Tank (1) according to any one of claims 1 to 4, wherein the opening (19) forms a single means of communication between the internal space (18) of the protrusion (16) and the housing (3) of the tank (1).

6. Tank (1) according to any one of claims 1 to 5, in which the protrusion (16) includes a first gas discharge conduit (27) passing through the partition (17) of the protrusion (16).

7. Tank (1) according to any one of claims 1 to 6, comprising a vacuum bell (25) covering the protrusion (16) and sealed tightly to the upper part (9) of the wall (2).

8. Tank (1) according to claim 7, in which the vacuum bell (25) is welded to the upper part (9) of the wall (2).

9. Tank (1) according to claim 6 in combination with any one of claims 7 or 8, wherein the discharge pipe (27) passes through the vacuum bell (25).

10. Tank (1) according to any one of claims 1 to 9, wherein the liquefaction device (20) includes a cooling means (31) for the second gas, the cooling means (31) being positioned outside the protrusion (16).

11. Tank (1) according to any one of claims 1 to 10, wherein the upper part (9) of the wall (2) comprises a gas dome (13) having a passage (15) defining an evacuation path (36) of the first gas in vapor form, the internal space (18) of the protrusion (16) being configured so that the heat exchange surface (29) of the liquefaction device (20) is positioned away from the evacuation path (36) of the first gas.

12. Tank (1) according to any one of claims 1 to 11, in which the protrusion (16) is welded to the upper part (9) of the wall (2).

13. Tank (1) according to claim 12, wherein the protrusion (16) includes a welding collar (23).

14. Tank (1) according to any one of claims 1 to 13, in which the first gas discharge pipe (27) and the second gas circulation pipe (28) pass through the partition (17) of the protrusion (16) on the same portion of the partition (17).

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