Gas storage and / or transport tank including a heat exchange device.

Abstract

Gas storage and / or transport tank including a heat exchange device.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) of which a lower volume (4) is intended to contain the first gas in liquid form and of which an upper volume (5) is intended to contain the first gas in gaseous form, the wall (2) having an upper part (9) having an internal surface (11) participating in delimiting the upper volume (5) of the compartment (3), characterized in that said tank (1) comprises a heat exchange device (13) passing through the upper part (9) of the wall (2) and equipped with a first heat exchange portion (17) disposed in the compartment (3) and a second heat exchange portion (18) disposed outside the compartment (3), the heat exchange device (13) comprising an internal space (23) containing a second gas capable of circulating from the first heat exchange portion (17) to the second heat exchange portion (18).(Figure 1).

Description

Title of the invention: Gas storage and / or transport tank comprising a heat exchange device.

[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 designed for the transport and / or storage of a gas and equipped with a heat exchange device located in the upper part of its wall. This device is designed to condense the gas, which is in the upper part of the tank 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 having an internal surface participating in delimiting the upper volume of the compartment, characterized in that said tank includes a heat exchange device passing through the upper part of the wall and equipped with a first heat exchange portion disposed in the compartment and a second heat exchange portion disposed outside the compartment, the heat exchange device including an internal space containing a second gas capable of circulating from the first heat exchange portion to the second heat exchange portion.

[0009] The first gas transported and / or stored in the tank is typically a gas with a very low boiling point, often at sub-zero temperatures, such as dihydrogen. During transport and / or storage, this first gas is predominantly in liquid form within the tank compartment. However, heat transfer can occur 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 limit consumption energy related to the management of the evaporation gas, that is, 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 form.

[0012] The heat exchange device, as previously described, is designed to cool and condense the first gas when it is in gaseous form in order to convert it back into liquid form. This prevents a pressure increase inside the tank housing.

[0013] The heat exchange device is a heat pipe. Its internal space is thus designed to contain the second gas, and is notably delimited by the first heat exchange portion and the second heat exchange portion.

[0014] Since the first heat exchange portion is positioned within the housing, when the second gas is located in the internal space at the level of the first heat exchange portion, heat exchange can then occur between the first gas and the second gas via this first heat exchange portion. Thus, the first gas, upon coming into contact with the first heat exchange portion, can transfer its heat to the second gas. The latter absorbs heat and tends to evaporate, and therefore then circulates within the heat exchange device, towards the second heat exchange portion, while the first gas, having released heat, condenses and can fall by gravity from the upper to the lower volume of the housing.

[0015] The second heat exchange portion is positioned outside the tank and serves to recondense the second gas in gaseous form into a second gas in liquid form present in the internal space at the level of the second heat exchange portion, so that it falls back into the internal space at the level of the first heat exchange portion in liquid form. Thus, by proposing a heat exchange device comprising a gas capable of changing from one state to another depending on the heat it recovers from a gas to be cooled and the same heat it transfers to a third fluid, a heat pipe is advantageously formed in a wall of a tank for transporting and / or storing a gas. This heat pipe is particularly effective at maintaining a maximum of gas in liquid form within the tank.

[0016] The heat exchange device is arranged so as to pass through the upper part of the tank. It should be understood that this upper part, by defining the upper volume of the housing, is the section of the wall that is in contact with the first gas in gaseous form.

[0017] In what follows, the invention is described on the basis of an example of a gravity-type heat pipe in which the second gas in liquid form passes from the second heat exchange portion to the first heat exchange portion by gravity. However, the invention remains within the scope of the invention if the second gas returns to the first heat exchange portion by capillary action. In such a case, the area between the two portions is equipped with a porous medium called a wick. The advantage of this configuration is its ability to function not only vertically, but also horizontally, and even against gravity. This results in greater flexibility in the location of the heat exchange device.

[0018] When the tank has the shape of a rectangular parallelepiped, it 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 tank with a prismatic shape.

[0019] According to an optional feature of the invention, the second gas is the same gas as the first gas intended to be contained in the tank.

[0020] For example, when the first gas is dihydrogen, the second gas is also dihydrogen.

[0021] In one embodiment of the invention, the first gas is not the same as the second gas. In this case, the boiling point of the second gas is preferably lower than or equal to that of the first gas.

[0022] According to an optional feature of the invention, the first heat exchange portion includes a means for enlarging a heat exchange surface of said first heat exchange portion.

[0023] All types of means of enlarging this heat exchange surface can be used, for example, bosses or recesses positioned on the first portion of the heat exchange, or even fins. Thanks to these modifications, the heat exchange surface between the first gas and the second gas is increased. This promotes better condensation of the first gas, thus allowing it to remain in a longer liquid state within the dwelling.

[0024] According to an optional feature of the invention, the heat exchange device includes a circulation circuit of a third gas participating in defining a heat exchange surface of the second heat exchange portion.

[0025] The third gas is used to establish a heat exchange with the second gas in order to cool it, which allows its condensation so that it can fall back into the internal space at the level of the first portion of heat exchange.

[0026] For this purpose, the second heat exchange portion includes a heat exchange surface between the second gas and the third gas. This heat exchange surface is partly defined by the circulation duct, through which the third gas flows.

[0027] According to an optional feature of the invention, the circulation duct is disposed at least in part within the second heat exchange portion.

[0028] It should therefore be understood that, in this case, the circulation duct passes through the internal space of the heat exchange device at the level of the second heat exchange portion. This circulation duct is in contact with the second gas in gaseous form present in this part of the internal space. In this way, there is a heat exchange between the second gas and the third gas, thus allowing the second gas to condense.

[0029] According to an optional feature of the invention, the third gas is a different gas from the second gas.

[0030] When the third gas is different from the second gas, it is preferable for the third gas to have a boiling point lower than or equal to that of the second gas. Of course, it is also possible to use a gas with a higher boiling point, but in this case, it must be cooled below its boiling point in order to remain cooler than the second gas. For example, when the second gas is dihydrogen, the third gas could be helium, the boiling point of dihydrogen being -252.8°C and the boiling point of helium being -268.9°C.

[0031] According to an optional feature of the invention, the upper part of the wall includes a passage through said upper part, the heat exchange device covering at least part of this passage.

[0032] It is thus understood that the first portion of heat exchange covers the passage from the side of the internal surface of the upper wall, while the second portion of heat exchange covers the passage from an external side of the upper wall to the tank.

[0033] Thus, when the second gas evaporates in the internal space at the level of the first heat exchange portion, it passes through the passage before arriving in the internal space at the level of the second heat exchange portion. After condensing in this internal space, the second gas passes through the passage again before returning in liquid form to the internal space at the level of the first heat exchange portion.

[0034] The heat exchange device comprises the first heat exchange portion, the second heat exchange portion, and the passage, but it should be understood that this passage does not need to be delimited by a specific conduit separate from the tank wall. Indeed, the fact that the first and second heat exchange portions cover the passage in a sealed manner provides fluid sealing between the two portions via the passage, which can thus be considered as forming part of the device. of the heat exchange device even if it is only delimited by the wall of the tank.

[0035] According to an optional feature of the invention, the first heat exchange portion and the second heat exchange portion are welded to the upper part of the wall, respectively on the internal surface of said upper part and on an external surface opposite to said internal surface.

[0036] Thus, by being welded respectively to the internal and external surfaces, the heat exchange portions ensure the airtightness of the internal space of the heat exchange device, both with respect to the tank housing for the first heat exchange portion and with respect to the external environment for the second heat exchange portion. Consequently, the second gas is not in direct contact with the first or third gas, but can exchange heat with these gases via the first and second heat exchange portions.

[0037] According to an optional feature of the invention, the first heat exchange portion and the second heat exchange portion respectively comprise a welding collar.

[0038] This welding collar facilitates welding the first and second heat exchange portions to the inner and outer surfaces of the wall. Furthermore, it strengthens the bond between the first heat exchange portion and the inner surface, and between the second heat exchange portion and the outer surface of the wall.

[0039] According to an optional feature of the invention, the heat exchange device comprises a vacuum bell covering the second heat exchange portion and connected in a hermetically sealed manner to the upper part of the wall.

[0040] By covering the second heat exchange portion, the vacuum bell helps prevent the transfer of heat from the external environment to the second heat exchange portion. This prevents it from heating up and avoids an increase in the energy required to cool the second gas. The presence of the vacuum bell therefore increases the efficiency of the heat exchange device.

[0041] According to an optional feature of the invention, the ratio between the surface area of ​​the first heat exchange portion and the area of ​​a cross-section of the passage is between 200 / 1 and 10000 / 1. This ratio is given by way of non-limiting example when approximately 90 kg / h of condensation is desired. Similarly, numerical values ​​are given below by way of illustration, but they are in no way limiting. Based on the description of the invention, a person skilled in the art will understand that the size of the heat pipe depends on the amount of heat to be transferred through the heat pipe. Likewise, the characteristics of the Heat pipes depend on the size of the tank, the level of insulation of the tank and the ship's consumption.

[0042] The values ​​given here as an example correspond to a 10,000 m3 ship with a BOR (Boil-Off Rate) of 0.45% per day and a minimum consumption of 42 kg / h of dihydrogen.

[0043] The cross-section of the passage corresponds to the narrowest point of the passage. The area of ​​this cross-section can be between 0.01 m² and 0.1 m² when the desired condensation rate is approximately 90 kg / h. If this area is too small, and therefore the cross-section of the passage too small, the flow velocity of the second gas can be sufficiently high and generate pressure losses. With this configuration, the flow velocity can be maintained between 0.5 and 3 m / s.

[0044] The area of ​​the exchange surface of the first portion of heat exchange can be between 20 and 100 m2, for example between 30 and 50 m2. This area depends mainly on the size of the tank and therefore on the quantity of first gas likely to be in gaseous form.

[0045] Regarding the exchange surface area of ​​the second portion of heat exchange, it is between 25 and 110 m2, for example between 35 and 55 m2 in order to ensure that the second gas is properly condensed.

[0046] 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:

[0047] [Fig-1] is a cross-sectional view of a tank 1 used for the transport and / or storage of a first gas.

[0048] [Fig.2] is a cross-sectional view of a first embodiment of a heat exchange device.

[0049] [Fig.3] is a cross-sectional view of a second embodiment of the heat exchange device.

[0050] 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.

[0051] In the figures, elements common to several figures retain the same reference numeral. The proper functioning of a heat pipe depends on a volume and mass of fluid well suited to the application. This is why these The heat exchange devices are sealed during construction. This prevents leaks and protects against any mass variation. Therefore, the illustrative nature of the figures should be kept in mind for the purpose of describing the invention.

[0052] Fig. 1 is a cross-sectional view of a tank 1 used for the transport and / or storage of a first gas.

[0053] 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, liquid natural gas are also conceivable.

[0054] 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, intended to contain the first gas. The wall 2 therefore serves to form this internal void space by delimiting the compartment 3.

[0055] Within this housing 3, the first gas can be present in different states. It is originally stored in the tank 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.

[0056] 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.

[0057] 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.

[0058] We can thus distinguish within the wall an upper part 9 and a lower part 10, separated from each other by the floating surface of the liquid gas. The upper part 9 comprises an internal surface 11 delimiting the upper volume 5 of the housing 3, while the lower part 10 comprises an internal surface 12 delimiting the lower volume 4 of the housing 3. Thus, the upper part 9 of the wall 2 is in contact with the first gas, when it is in the gaseous phase, via its internal surface 11, while the lower part 10 is in contact with the first gas, when it is in liquid form, via its internal surface 12.

[0059] 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 partition The upper partition 6 forms the floor of tank 1. The upper partition 6 forms the ceiling of tank 1. The side partitions 8 connect the upper partition 6 to the bottom partition 7. Thus, when tank 1 is placed on a flat and horizontal surface, the bottom partition 7 and the upper partition 6 are substantially horizontal, while the side partitions 8 are substantially vertical.

[0060] 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.

[0061] The tank 1 also includes a heat exchange device 13, which is positioned at the upper part 9 of the wall 2. More specifically, this heat exchange device passes through the wall 2 of the tank 1, at the upper part 9.

[0062] The device is said to be through-the-wall insofar as it comprises a portion outside the housing, a portion inside the housing and a zone connecting the two portions and housed through the wall.

[0063] The role of the heat exchange device 13 is to condense the first gas in gaseous form contained in the upper volume 5 of the housing 3, so that it becomes liquid again and takes position, by gravity, in the lower volume 4 of the housing 3.

[0064] Condensation occurs through heat exchange with the portion of the device that is present in the housing 3 and more particularly in the upper volume 5 of the housing, that is to say the portion of the device that is directly in contact with the first gas in vapor form.

[0065] The trajectories of the first gas are represented in the figure by arrows A and B. Arrows A represent upward trajectories of the first evaporated gas, while arrows B represent downward trajectories of the first gas which has become liquid again in contact with the heat exchange device.

[0066] Fig. 2 is a cross-sectional view of a first embodiment of the heat exchange device 13.

[0067] This heat exchange device 13 is positioned at a location in the upper part 9 of the wall 2 where there is a passage 14. This passage 14 extends through the wall 2 from a first opening 15 on the side giving into the housing 3 of the tank 1 to a second opening 16 giving to the outside of the tank 1.

[0068] The heat exchange device 13 is composed of a first heat exchange portion 17 and a second heat exchange portion 18. The first portion The heat exchanger 17 is located inside the housing 3 of the tank 1. More specifically, it is positioned in contact with the internal surface 11 of the upper part 9 of the wall 2 and covers the first opening 15 of the passage 14. The first portion of the heat exchanger 17 thus comprises side walls 191 which are in contact with the internal surface 11 of the upper part 9 of the wall 2 and a cover wall 192 which extends parallel to this internal surface 11, at a distance from it.

[0069] These side walls 191 are securely attached, for example by welding, to the inner surface 11 of the upper part 9 to secure the attachment of the first heat exchange portion 17 to the upper part 9 of the wall 2, thus preventing any risk of detachment and any passage of fluid from the inside of the first heat exchange portion to the inside of the tank. To reinforce this attachment, the side walls 191 can be welded to the inner surface 11 of the upper part 9 via flanges 20 forming a base for the side walls on the periphery of the first heat exchange portion 17 and intended to increase the strength of the weld between the first heat exchange portion 17 and the inner surface 11 of the upper part 9 of the wall 2.

[0070] The second heat exchange portion 18 of the heat exchange device 13 is positioned outside the housing 3, i.e. outside the tank 1. More precisely, the second heat exchange portion 18 is in contact with an external surface 21 of the upper part 9 of the wall 2, and it covers the passage 14, in particular the second opening 16 of this passage 14. The second heat exchange portion 18 comprises side walls 221 which are fixed to the external surface 21 of the upper part 9 of the wall 2 and a cover wall 222 which extends parallel to this internal surface 11, at a distance from it.

[0071] Similar to the side walls 191 of the first heat exchange portion 17, the side walls 221 of the second heat exchange portion 18 are welded to the external surface 21, and these side walls 221 may also include flanges 20, serving to increase the strength of the weld between the second heat exchange portion 18 and the external surface 21 of the upper part 9 of the wall 2.

[0072] The second heat exchange portion 18 also includes, in the illustrated example, return edges 223 arranged in contact with the external surface 21 of the upper part 9 of the wall 2 and connected to the side walls 221. It should be noted that the return edges 223 thus form a base of the second heat exchange portion extending from the side walls 221 to the second opening 16.

[0073] The return edges 223 are here inclined in such a way that, if liquid comes to be deposited on the return edges 223, this liquid can flow by gravity to the second opening 16.

[0074] The return edges 223 may include a collar 224 cooperating with the second opening 16 of the passage and allowing that, when a liquid flows over the return edge, said liquid is guided into the passage 15 without the possibility of it seeping between the external surface 21 and the return edges 223.

[0075] Thanks to their positioning, the first heat exchange portion 17, the second heat exchange portion 18 and the passage 14 delimit an internal sealed space 23 within the heat exchange device 13. This internal space 23 is made sealed with respect to the housing 3 of the tank 1 and the external environment, thanks to the welds of the side walls 191, 221 of each heat exchange portion.

[0076] This internal space 23 is functionally subdivided into three zones: an evaporation zone 24, a transfer zone 25, and a condensation zone 26.

[0077] The evaporation zone 24 is delimited by the first portion of heat exchange 17 and the internal surface 11 of the upper part 9 of the wall 2, and it extends to the first opening 15.

[0078] The condensation zone 26 is delimited by the second heat exchange portion 18 and the external surface 21 of the upper part 9 and it extends to the second opening 16. The transfer zone 24 corresponds to the empty space inside the passage 14 and is therefore delimited by the first opening 15 and the second opening 16 of this passage 14, so that it communicates on one side with the evaporation zone 24 and on the other side with the condensation zone 26.

[0079] Within this internal space 23 circulates a second gas, which can be dihydrogen when the first gas is also dihydrogen. The hydrogen used as the second gas is then present in the heat exchange device 13 at a pressure lower than that of the hydrogen used as the first gas within the tank 1.

[0080] This second gas circulates between the first heat exchange portion 17 and the second heat exchange portion 18, and vice versa. More precisely, the second gas is predominantly in liquid form when it is in the evaporation zone 24. When it is heated and absorbs heat from the first gas, through the wall of the first heat exchange portion 17, it changes into a gaseous state and then passes through the transfer zone 25 to reach the condensation zone 26. The second gas is then condensed, releasing heat outside the tank through the wall of the second heat exchange portion 18, before passing back through the transfer zone 25 and returning to the evaporation zone 24 under the effect of gravity.

[0081] The operation of the transfer zone and therefore the circulation of the second gas is represented in the figures by arrows C and D. Arrow C illustrates the second gas in gaseous form which circulates from the evaporation zone 24 to the condensation zone 26. Arrow D, for its part, represents the second gas in liquid form, after condensation, which circulates from the condensation zone 26 to the evaporation zone 24.

[0082] The second gas is in direct contact with the first portion of heat exchange 17, which allows heat exchange due to the temperature differences between the first gas and the second gas through this first portion of heat exchange 17. The material of the first portion of heat exchange 17 is therefore chosen from materials having high thermal conductivity.

[0083] In order to intensify this heat exchange between the first gas, contained in the upper volume 5, and the second gas, located in the evaporation zone 24, the first portion of heat exchange 17 includes a means of enlarging 27 its heat exchange surface between the first gas and the second gas.

[0084] In this embodiment, the enlargement means 27 consists of bosses oriented towards the housing 3 of the tank 1 and / or towards the evaporation zone. As shown in the figure, the exchange surface is notably increased here between the first gas in vapor form and the cover wall 222 of the first portion of heat exchange 17, which allows for better heat recovery from the first gas in vapor form. The same principle applies when bosses are oriented towards the evaporation zone. Alternatively, the enlargement means 27 can consist of fins or roughened surfaces to promote nucleation and encourage boiling.

[0085] It should be emphasized that the example of bosses is not limiting; other means of enlarging the heat exchange surface can be used, such as hollows, fins and other types of structures.

[0086] In order to condense the second gas in the condensation zone 26, the second heat exchange portion 26 comprises a heat exchange surface where an exchange occurs between the second gas and a third gas. This third gas is preferably a gas having a lower liquefaction point than that of the second gas, for example helium when the second gas is dihydrogen.

[0087] In this example, where helium is used as the third gas, dihydrogen as the second gas, and dihydrogen as the first gas, the internal space of the heat pipe can be underpressurized, for example, to 0.6 bar. This pressure lowers the boiling point of dihydrogen to -254.5 °C, while that of the first gas remains at -252.5 °C. Thus, dihydrogen, as the second gas, will accumulate more heat before evaporating. In this example, the helium circulating as the third gas may have a temperature of -259 °C before heat exchange, and then a temperature -256.5 °C after heat exchange. Note that this is an example of pressure in the heat pipe during operation. When stopped and under ambient conditions, the pressure in the heat pipe would be higher (for example, 10 bar).

[0088] An equilibrium pressure will be established (for example 0.6 bar) at which the evaporation temperature of the second gas is low enough to extract calories from the first gas.

[0089] There is therefore a temperature difference between the first gas, the second gas, and the third gas. Here, a temperature difference means that the boiling points of the first and second gases are not the same. Similarly, the boiling points of the second and third gases are different.

[0090] The heat exchange device 13 thus comprises a circulation conduit 28 through which the third gas circulates. This circulation conduit 28 constitutes in part the heat exchange surface between the second and third gases.

[0091] The portion of the circulation duct 28, positioned within the condensation zone 26 and forming the heat exchange surface, preferably has a serpentine shape to increase the area of ​​the heat exchange surface thus formed between the second and third gases. In the illustrated example, the circulation duct extends along a major part of the cover wall 222, from the vicinity of a first lateral wall 221 of the first heat exchange portion 18 to the vicinity of an opposite lateral wall 221, passing over the second opening 16. Alternatively, the circulation duct can be integrated into the cover wall 222.Thus, it must be understood that the circulation duct 28, located at least partially within the second heat exchange portion 18, can be inside the second heat exchange portion 18 and / or within the wall of the second heat exchange portion 18 and / or outside the second heat exchange portion 18. In this last variant, the second heat exchange portion 18 can include, similarly to the first heat exchange portion, a means of enlarging its heat exchange surface area between the second and third gases. For example, this could consist of external bosses or fins exchanging heat with the helium in gaseous form under forced circulation.

[0092] Thus, the portion of the circulation duct 28 positioned within the condensation zone 26 efficiently condenses the second gas passing from the first heat exchange portion 17 to the second heat exchange portion 18. It should be noted that during condensation, the second condensed gas can fall back by gravity into an area near the side walls of the second heat exchange portion 18. The second gas is then advantageously returned to the second opening 16 of the passage 15 via the inclination of the return edge 223.

[0093] The second heat exchange portion 18 is therefore distinguished from the first heat exchange portion 17 in that the heat exchange of the second gas takes place via the circulation duct 28 positioned within the condensation zone 26 and not directly via the side walls 221 and the cover wall 222 constituting the second heat exchange portion 17.

[0094] The second gas, in gaseous form, then condenses upon contact with the circulation duct 28 which carries the third gas, due to the temperature differential. The third gas, thus heated, is removed from the second heat exchange portion 18, for example by means of a pump, and the heat extracted from the second gas is thereby dissipated.

[0095] Since the heat exchange device 13 forms a sealed internal space 23, it is necessary to use a gas inlet means 29 to introduce the second gas into the heat exchange device 13. In this embodiment, this inlet means 29 is positioned on the second heat exchange portion 18, which facilitates the filling of the second gas since it is therefore located outside the housing 3 of the tank 1. It should be noted that this positioning of the inlet means 29 is not limiting and that other placements, whether on the first heat exchange portion 17 or the second heat exchange portion 18, are possible.

[0096] The heat exchange device 13 is sized to be able to remove sufficient heat from the initial gas so that this first gas can be properly condensed. Thus, depending on the type of gas present in the tank, and depending on the choice of the second and third gases used to successively remove heat, the dimensions of the heat exchange portions can vary.

[0097] In particular, the heat exchange surface area of ​​the first heat exchange portion 17, which corresponds to the area of ​​the side walls 191 combined with that of the cover wall 191 and that of the extension means 27, can be between 20 and 100 m². The heat exchange surface area of ​​the second heat exchange portion 18 consists of an external peripheral surface of the portion of the circulation duct 28 positioned within the condensation zone 26, as opposed to an internal surface of the duct along which the third gas circulates. This external peripheral surface area can be between 25 and 110 m².

[0098] Passage 14 includes a section where its area is the smallest. This section must therefore have an area between 0.01 and 0.1 m2.

[0099] The ratio between the area of ​​the heat exchange surface of the first portion of heat exchange 17 and the area of ​​the narrowest section of the passage 14 is therefore between 200 / 1 and 10000 / 1.

[0100] This ratio allows a passage speed of the first portion of heat exchange to the second portion of heat exchange, of the second gas in gaseous form, through this section which is between 0.5 and 3 m / s.

[0101] Fig. 3 is a cross-sectional view of a second embodiment of the heat exchange device 13.

[0102] In this second embodiment, the heat exchange device 13 comprises a vacuum bell 30. This vacuum bell 30 is positioned around the second heat exchange portion 18 and is hermetically sealed to the upper part 9 of the wall 2. More specifically, the vacuum bell 30 is attached to the external surface 21 of the upper part 9 of the wall 2, for example by means of collars 31 which can be welded to this external surface 21.

[0103] The vacuum bell 30 forms a vacuum space around the second heat exchange portion 18. This arrangement thus isolates the second heat exchange portion 18 from the external environment, thereby allowing a more efficient heat transfer between the second gas and the third gas by preventing the ambient air from heating the side walls 191 and the cover wall 192 delimiting the second heat exchange portion.

[0104] In this embodiment, the gas inlet means 29 passes through both one of the side walls 221 of the second heat exchange portion 18 and the vacuum bell 30. In this arrangement, the inlet means 29 thus makes it possible to fill the internal space 23 of the heat exchange device 13 with the second gas without having to remove the vacuum bell 30.

[0105] In addition, the circulation conduit 28 of the third gas passes through the vacuum bell 30 and the second heat exchange portion 18, and more specifically its cover wall 222.

[0106] The other features of this second embodiment are similar to those previously described in the first embodiment.

[0107] 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 heat exchange device of the heat pipe type, that is to say, using a second gas, trapped within the heat exchange device, this heat pipe being able, in particular, to be located in the upper part of the tank wall. The use of such a type of heat exchange device optimizes the condensation process of the first gas, which is in the liquid state gaseous in the upper part of the tank. The major advantage of this invention is that it allows the gas to be condensed while consuming significantly less energy than traditional systems described in the prior art.

[0108] The present invention is not limited to the means and configurations described and illustrated herein and also extends to any equivalent means and configuration as well as to any technically operative combination of such means.

Claims

Demands

1. Tank (1) for the transport and / or storage of a first gas, comprising a wall (2) delimiting a compartment (3) of which a lower volume (4) is intended to contain the first gas in liquid form and an upper volume (5) is intended to contain the first gas in gaseous form, the wall (2) having an upper part (9) having an internal surface (11) participating in delimiting the upper volume (5) of the compartment (3), characterized in that said tank (1) comprises a heat exchange device (13) passing through the upper part (9) of the wall (2) and equipped with a first heat exchange portion (17) disposed in the compartment (3) and a second heat exchange portion (18) disposed outside the compartment (3), the heat exchange device (13) comprising an internal space (23) containing a second gas capable of circulating from the first heat exchange portion (17) to the second heat exchange portion (18).

2. Tank (1) according to claim 1, wherein the second gas is the same gas as the first gas intended to be contained in the tank (1).

3. Tank (1) according to any one of claims 1 or 2, wherein the first heat exchange portion (17) comprises a means for enlarging (27) a heat exchange surface of said first heat exchange portion (17).

4. Tank (1) according to any one of claims 1 to 3, wherein the heat exchange device (13) includes a circulation circuit (28) of a third gas participating in defining a heat exchange surface of the second heat exchange portion (18).

5. Tank (1) according to claim 4, in which the circulation conduit (28) is disposed at least partly within the second heat exchange portion (18).

6. Tank (1) according to any one of claims 4 or 5, wherein the third gas is a different gas from the second gas.

7. Tank (1) according to any one of claims 1 to 6, wherein the upper part (9) of the wall (2) includes a passage (14) through said upper part (9), the heat exchange device (13) covering at least part of this passage (14).

8. Tank (1) according to any one of claims 1 to 7, wherein the first heat exchange portion (17) and the second heat exchange portion (18) are welded to the upper part (9) of the wall (2), respectively on the internal surface (11) of said upper part (9) and on an external surface (21) opposite said internal surface (11).

9. Tank (1) according to claim 8, wherein the first heat exchange portion (17) and the second heat exchange portion (18) respectively comprise a welding collar (20).

10. Tank (1) according to any one of claims 1 to 9, wherein the heat exchange device (13) comprises a vacuum bell (30) covering the second heat exchange portion (18) and hermetically connected to the upper part (9) of the wall (2).

11. Tank (1) according to any one of claims 1 to 10 in combination with claim 7, wherein the ratio between an area of ​​the exchange surface of the first portion of heat exchange (17) and an area of ​​a section of the passage (14) is between 200 / 1 and 10000 / 1.

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