Leaktight and thermally insulating vessel, and associated method for placing under vacuum

Abstract

The invention relates to a vessel comprising an intermediate space, and to a method for placing under vacuum, for placing an intermediate space in a leaktight and thermally insulating vessel (1) under vacuum. The intermediate space (30) comprises a gas phase, the gas phase consisting of one or more main chemical species and optionally one or more residual chemical species. The or each main chemical species has a saturation vapour pressure, at any temperature below 126 K, that is less than the saturation vapour pressure of nitrogen at said temperature below 126 K. The pressure in the intermediate space (30) is at an absolute pressure below a pressure threshold, said pressure threshold being less than the triple point of said or each main chemical species. The or each residual chemical species is at a partial pressure of less than 0.1 kPa.

Description

Sealed and thermally insulating tank and associated vacuum process

[0001] The invention relates to the field of sealed and thermally insulating tanks for the storage and / or transport of liquefied gas at low temperature, such as a tank for the transport of liquid hydrogen, which is at approximately -253°C at atmospheric pressure but which can also be stored under a higher pressure. These tanks can be installed in a fixed position or on any land or floating vehicle. Technological background

[0002] Self-supporting land-based tanks are known for the storage and / or transport of liquefied gas at atmospheric pressure.

[0003] Membrane tanks are also known for storing and / or transporting liquefied natural gas at atmospheric pressure. Such a tank comprises, for example, a tank wall having successively, in the direction of the thickness, from the inside to the outside of the tank, a primary sealing membrane intended to be in contact with the liquefied natural gas, a primary thermally insulating barrier, a secondary sealing membrane, a secondary thermally insulating barrier and a supporting structure defining the general shape of the tank.

[0004] The primary and secondary waterproofing membranes delimit between them a primary space which contains the primary insulating barrier.

[0005] In order to keep the gas in liquid form inside the tank, it is important that the tank has excellent thermal insulation properties. Indeed, such a tank must limit as much as possible the heating of the liquefied gas contained inside the tank and must limit thermal conduction towards the outside of the tank which could damage elements sensitive to low temperatures.

[0006] It is known for example in the document Glass bubbles insulation for liquid hydrogen storage tanks, JP Sass, WW St. Cyr, TM Barrett, RG Baumgartner, JW Lott, and JE Fesmirel, June 30, 2009 to reduce the pressure of the intermediate space of a self-supporting spherical tank in order to improve the thermal insulation properties of the tank.

[0007] However, the process of vacuuming such an intermediate space using vacuum pumps in the tank is a time-consuming and energy-consuming process.

[0008] In other words, it is difficult to extract all the air initially present in space. Thus, it is difficult to extract nitrogen and oxygen which are the main constituents of air.

[0009] Summary

[0010] Certain aspects of the invention are based on the observation that when the tank is cooled, chemical species such as oxygen and nitrogen initially in the gaseous phase can condense in the liquid phase and possibly subsequently solidify in the solid phase if the pressure and temperature decrease sufficiently. Thus, nitrogen, for example, can easily spread into the primary space in the liquid phase and then solidify.

[0011] This phenomenon causes damage to the tank, including a reduction in the thermal insulation properties of the tank due to the formation of liquid or ice spread throughout the thickness of the primary space, thus forming thermal bridges.

[0012] One idea behind the invention is to propose a vacuum method for creating a vacuum in an intermediate space in a sealed and thermally insulating tank.

[0013] Another idea underlying the invention is to propose an improved vacuum method for creating a vacuum in an intermediate space in a sealed and thermally insulating tank, presenting advantages in terms of speed and energy consumption.

[0014] Another idea underlying the invention is to propose a vacuum method for creating a vacuum in an intermediate space in a sealed and thermally insulating tank, which is more energy-efficient and less expensive than known vacuum methods.

[0015] Another idea underlying the invention is to propose a sealed and thermally insulating tank comprising a gas phase in an intermediate space having excellent physicochemical properties.

[0016] In particular, an idea underlying the invention is to provide a gaseous phase in an intermediate space under conditions allowing said gaseous phase, in the event of a decrease in temperature, to condense from a gaseous phase to a solid phase without passing through a liquid phase.

[0017] According to one embodiment, the invention provides a vacuum method for evacuating an intermediate space in a sealed and thermally insulating tank, the sealed and thermally insulating tank comprising an outer sealed wall, an inner sealed wall located at a distance from an inner side of the outer sealed wall and defining an inner space intended to contain liquefied gas, preferably hydrogen and an intermediate space located between the outer sealed wall and the inner sealed wall, the method comprising the steps of: - replacing a gaseous phase present in the intermediate space with a replacement gaseous phase at a first temperature, the first temperature being greater than 273 K, the replacement gaseous phase consisting of one or more main chemical species, and possibly one or more residual chemical species,replacing the gas phase comprising the step of injecting the replacement gas phase into the intermediate space at a first pressure, the first pressure in the intermediate space being less than 500 kPa absolute, wherein the or each principal chemical species is in the gaseous state at the first temperature and at a partial pressure lower than the first pressure, wherein the or each principal chemical species has a saturated vapor pressure at any temperature below 126 K lower than the saturated vapor pressure of nitrogen at said temperature below 126 K,- lowering the pressure in the intermediate space to an absolute pressure below a pressure threshold, and- cooling the tank by injecting a fluid at a second temperature below 273K into the internal space of the tank, wherein the pressure threshold is below the triple point of said or each principal chemical species,to condense into the solid phase said or each main chemical species when the tank is cooled, and in which the or each residual chemical species is at a partial pressure of less than 0.1 kPa.,

[0018] The gas phase initially present includes, for example, air which is mainly made up of nitrogen and oxygen. It is therefore important to replace this gas phase initially present in order to prepare the evacuation of the intermediate space. Thus, the or each main chemical species is in the gaseous state before the tank is cooled and condenses into the solid state in the form of snow or ice cubes, when the temperature decreases, without passing through the liquid state. Thus, this condensation considerably reduces the volume occupied by the main chemical species and therefore the pressure prevailing in the intermediate space. In addition, the risk of a chemical species present in the intermediate space condensing in the liquid phase and spreading into the primary space is greatly reduced. The formation of thermal bridges across the intermediate space is also greatly reduced.

[0019] According to embodiments, such a vacuum method may comprise one or more of the following features.

[0020] According to one embodiment, the first pressure is less than 110 kPa absolute. Thus, the pressure forces on the sealed walls are moderate, which allows relatively light constructions, particularly in the form of membranes.

[0021] According to one embodiment, the pressure threshold is less than 1 kPa, preferably less than 0.1 kPa. Thus, the quantity of material likely to condense during cooling is relatively low.

[0022] According to one embodiment, the saturated vapor pressure at any temperature below 126 K of the or each main chemical species is lower than the saturated vapor pressure of nitrogen at the temperature below 126 K in a ratio of less than 1 / 10, preferably a ratio of less than 1 / 1000, even more preferably a ratio of less than 1 / 10000.

[0023] According to one embodiment, the or each residual chemical species is at a partial pressure less than 10 Pa, preferably less than 1 Pa.

[0024] Thus, the quantity of residual chemical species present in the space that could potentially condense in the liquid phase is very low. Thanks to these characteristics, the thermal insulation capacities of the tank are therefore preserved.

[0025] According to one embodiment, the or each main chemical species is chosen from: carbon dioxide and trans-1,3,3,3-Tetrafluoropropene.

[0026] According to one embodiment, the replaced gas phase comprises carbon dioxide as the sole principal species.

[0027] Thus, when the tank is cooled, the carbon dioxide will condense in the solid phase without passing through the liquid phase and form a more or less porous solid phase. Carbon dioxide is a preferred main species that can easily be condensed into the solid phase during the tank's cooling. The phase transition of carbon dioxide from the gaseous phase to the solid phase leads to a further decrease in pressure in the intermediate space. Thus, the thermal insulation properties of the tank are increased.

[0028] According to one embodiment, the replacement of the gaseous phase present in the intermediate space comprises: sucking said gaseous phase present in the intermediate space towards the outside of the external sealed wall until the absolute pressure in the intermediate space is lower than a second pressure threshold, in which the second pressure threshold is lower than 20 kPa, preferably lower than 10 kPa, even more preferably lower than 1 kPa, then injecting the replacement gaseous phase into the intermediate space.

[0029] According to one embodiment, the steps of suctioning the gas phase present in the intermediate space and injecting the replacement gas phase are carried out repeatedly.

[0030] According to one embodiment, the replacement of the gas phase present in the intermediate space comprises simultaneously sucking said gas phase present in the intermediate space towards the outside of the external sealed wall and injecting the replacement gas phase into the intermediate space, in order to carry out a sweeping of the intermediate space with the replacement gas phase.

[0031] According to one embodiment, the first temperature is greater than 330 K, preferably greater than 373.15 K. Thus, the water present in the intermediate space at ambient pressure is vaporized and can be easily evacuated from this intermediate space.

[0032] According to one embodiment, the cooling of the tank is carried out by spraying the fluid into the internal space of the tank.

[0033] According to one embodiment, the cooling of the tank is carried out by filling the internal space of the tank via a filling line opening into a bottom part of the tank.

[0034] According to one embodiment, the fluid is liquid hydrogen.

[0035] According to one embodiment, the fluid is liquid argon, liquid helium or liquid nitrogen.

[0036] According to one embodiment, the sealed and thermally insulating tank comprises a secondary sealed membrane located between the outer sealed wall and the inner sealed wall, the intermediate space being formed between the secondary sealed membrane and the inner sealed wall, the inner sealed wall being a primary sealed membrane, wherein the intermediate space comprises support elements extending in the thickness direction to support the primary sealed membrane.

[0037] Such support elements can be made in many ways, for example in the form of blocks of insulating material, rigid boxes, pillars, spacer walls, etc.

[0038] According to one embodiment, the invention also provides a sealed and thermally insulating tank comprising an outer sealed wall, an inner sealed wall located at a distance from an inner side of the outer sealed wall and defining an inner space intended to contain liquefied gas, preferably hydrogen and an intermediate space located between the outer sealed wall and the inner sealed wall, in which the intermediate space comprises a gaseous phase, the gaseous phase consisting of one or more main chemical species, and optionally one or more residual chemical species, in which the or each main chemical species has a saturation vapor pressure at any temperature below 126 K lower than the saturation vapor pressure of nitrogen at said temperature below 126 K, in which the gaseous phase in the intermediate space is at an absolute pressure lower than a pressure threshold,said pressure threshold being lower than the triple point of said or each principal chemical species, and wherein the or each residual chemical species is at a partial pressure lower than 0.1 kPa.,

[0039] According to one embodiment, the internal space contains liquefied gas, the liquefied gas having a temperature less than 273 K.

[0040] According to one embodiment, the internal space contains liquefied gas, the liquefied gas having a temperature less than 173 K, preferably less than 123 K, for example less than 50 K.

[0041] According to one embodiment, the internal space contains liquid hydrogen.

[0042] According to one embodiment, said or each main chemical species is chosen from: carbon dioxide and trans-1,3,3,3-Tetrafluoropropene

[0043] According to one embodiment, carbon dioxide is the sole principal species of the gas phase.

[0044] According to one embodiment, the tank comprises a secondary waterproof membrane located between the outer waterproof wall and the inner waterproof wall, the intermediate space being formed between the secondary waterproof membrane and the inner waterproof wall, the inner waterproof wall being a primary waterproof membrane, in which the intermediate space comprises a primary thermally insulating barrier supporting the primary waterproof membrane.

[0045] Such a tank may be part of a land-based storage facility, for example for storing liquid hydrogen, or installed in a floating, coastal, or deep-water structure, including a ship, a floating storage and regasification unit (FSRU), a floating production and remote storage unit (FPSO), and others.

[0046] According to one embodiment, a ship for the transport of a liquefied gas, preferably for the transport of hydrogen, comprises a double hull and a aforementioned tank arranged in the double hull.

[0047] According to one embodiment, the double hull comprises an internal hull forming the supporting structure of the tank.

[0048] According to one embodiment, the invention also provides a transfer system for liquefied gas, the system comprising the aforementioned vessel, insulated pipes arranged to connect the tank installed in the hull of the vessel to a floating or land-based storage facility and a pump for driving liquefied gas through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

[0049] According to one embodiment, the invention also provides a method of loading or unloading such a vessel, in which a liquefied gas is conveyed through insulated pipes from or to a floating or land-based storage facility to or from the vessel's tank. Brief description of the figures

[0050] The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes, with reference to the accompanying drawings.

[0051] The figure represents a cutaway perspective view of a sealed and thermally insulating membrane tank according to one embodiment.

[0052] This is a partial schematic and sectional view of a portion of the tank of the.

[0053] This is a sectional view of an intermediate space of the tank of the.

[0054] This is a cutaway view of a self-supporting tank according to another embodiment

[0055] This is a schematic cutaway representation of a ship's tank and a terminal for loading / unloading this tank.

[0056] Illustrates a log / log scale diagram showing the evolution of the saturated vapor pressures of several chemical species as a function of temperature.

[0057] In connection with the, we observe a sealed and thermally insulating tank 1 intended to receive a liquefied gas, for example liquid hydrogen. The tank 1 rests on a supporting structure formed by the internal hull (not shown) of a double-hulled ship (not shown). The tank 1 has a generally polyhedral or prismatic shape. The tank 1 has a first transverse wall 2 and a second transverse wall 3, here of octagonal shape. In the, the first transverse wall 2 is only partially shown in order to allow the internal space of the tank 1 to be visualized. The tank 1 also comprises a ceiling wall 4, a bottom wall 5, lower chamfer walls 6, side walls 7 and upper chamfer walls 8.The ceiling wall 4, the bottom wall 5, the lower chamfer walls 6, the side walls 7, and the upper chamfer walls 8 extend in the longitudinal direction of the ship, connect the first and second transverse walls 2, 3 at transverse edges 9, and meet at longitudinal edges 10.

[0058] The sealed and thermally insulating tank 1 comprises from the outside to the inside of the tank 1, in relation to the: an external sealed wall 11, a secondary thermally insulating barrier 20 which is fixed to the external sealed wall 11, the secondary thermally insulating barrier 20 comprising blocks of insulating foams, a corrugated secondary sealed membrane 24 carried by the thermally insulating barrier 20, an intermediate space 30 comprising a gas phase and a primary thermally insulating barrier 25 comprising support pillars, a primary sealed membrane 26 carried by the primary thermally insulating barrier 25, the primary sealed membrane 26 being intended to be in contact with the liquefied gas contained in the tank 1.

[0059] The gas phase of the intermediate space 30 consists of one or more main chemical species, for example consisting of carbon dioxide, and possibly one or more residual chemical species.

[0060] The or each main chemical species has a saturation vapor pressure at any temperature below 126 K that is lower than the saturation vapor pressure of nitrogen at said temperature below 126 K. In other words, the or each chemical species is chosen from species that are located to the right of N2 as illustrated on the log / log scale diagram of the. On a log / log scale, the saturation vapor pressure curves of the chemical species are almost all identical but shifted in temperature. However, beyond 126 K, the equilibrium curve of N2 stops and it is no longer possible to compare the saturation vapor pressure difference with other chemical species.

[0061] The pressure in the intermediate space 30 is at an absolute pressure lower than the triple point of said or each principal chemical species.

[0062] The or each residual chemical species is at a partial pressure less than 0.1 kPa.

[0063] In another embodiment, the tank 111 is a self-supporting tank and comprises, from the outside to the inside: a supporting structure 12, an external sealed wall 110, an intermediate space 130 comprising a gas phase and a thermally insulating barrier 125, an internal sealed wall 126, and an internal space 13 intended to contain liquefied gas, for example liquid hydrogen. As an alternative to the self-supporting tank, the tank may be of the inverted membrane type, that is to say comprising a rigid internal wall and a flexible membrane at a distance from the rigid internal wall.

[0064] The gas phase of the intermediate space 130 illustrated in the may be identical to the gas phase of the intermediate space 30 illustrated in Figures 2 and 3.

[0065] There will be described below, in relation to the, a method for evacuating an intermediate space in a sealed and thermally insulating tank according to one embodiment.

[0066] Identical or similar items with the same reference numbers.

[0067] The process for creating a vacuum in an intermediate space in a sealed and thermally insulating tank involves:

[0068] Replace the gas phase present in the interspace with a replacement gas phase at a temperature above 273 K.

[0069] The replacement of the gas phase is carried out via a gas management installation 110 connected to tank 1.

[0070] The gas management installation 110 comprises: a supply line 40 connected to a gas source 41 and to a compressor 50 and opening into the intermediate space 30. The gas source 41 comprises a gas reservoir filled with a said main species or a gas generator capable of generating a said main species, for example carbon dioxide. a suction line 42 connected to a vacuum pump 43 and opening into the intermediate space 30.

[0071] The gas management installation 110 may further comprise various elements for setting and monitoring the injection and suction of gas. For example, the gas management installation 110 comprises one or more devices chosen from: a gas analyzer 44 extracted from the secondary space by the suction line 42, a gas inlet flow meter 46 and / or gas outlet flow meter 45, a control unit 47, a pressure sensor 48 located in the intermediate space 30, a temperature sensor 49 located in the intermediate space 30.

[0072] Thus, the gas phase is replaced by performing a suction of the gas phase from the intermediate space 30 via the suction line 42 during which the vacuum pump 43 is activated, and an injection in which the or each main chemical species is injected in the gas phase from the gas source 41 into the intermediate space 30.

[0073] Optionally, this replacement operation can be performed repeatedly until the gas phase exhibits the desired parameters.

[0074] In a first example, the gas source is a source of CO2. In a second example, the gas source is a source of trans-1,3,3,3-Tetrafluoropropene.

[0075] The vacuum pump 43 is then activated to lower the pressure to an absolute pressure below the triple point of said or each principal chemical species.

[0076] In a first example, the triple point of carbon dioxide is 519 kPa at 217K. Thus, for carbon dioxide, the pressure will be lowered to an absolute pressure below 519 kPa.

[0077] In a second example, the triple point of trans-1,3,3,3-Tetrafluoropropene is located at 0.22 kPa at 168 K. Thus, for trans-1,3,3,3-Tetrafluoropropene, the pressure will be lowered to an absolute pressure below 0.22 kPa.

[0078] Then, the internal space 51 of the tank 1 is filled with liquefied gas, for example liquid hydrogen. Thus, the temperature of the intermediate space will decrease by heat transfer. The temperature of said or each main chemical species of the gas phase will decrease and said or each main chemical species will condense directly into the solid phase, without passing through the liquid state. This phenomenon will therefore make it possible to further reduce the pressure of the intermediate space.

[0079] Such a method described above can be applied in a similar manner to the self-supporting tank 111, illustrated on the and to other tanks having an intermediate space and intended to contain liquefied gas.

[0080] A comparison table of the main chemical species, nitrogen (N2), carbon dioxide (CO2) and trans-1,3,3,3-Tetrafluoropropene (R1234ze(E)) is described below:

[0081] [Table 1]:SpeciesT triple (K)P triple (kPa)Psat at 126K (kPa)Psat at 303K (kPa)R= Psat(N2) / Psat at 126KN2631.25x10 1 3.40x10 3 N / A (supercritical)1CO22175,19x10 2 1.40x10 -2 7.20x10 3 242857R1234ze(E)1682,20x10 -1 <0.225.80x10 2 >15455

[0082] The second column corresponds to the temperature in Kelvin (K) of the triple point of the main species indicated in the left column.

[0083] The third column corresponds to the pressure in kiloPascals (kPa) of the triple point of the main species indicated in the left column.

[0084] The fourth and fifth columns correspond to the saturation pressure (Psat), respectively at 126 K and 303 K of the main species indicated in the first column on the left.

[0085] The sixth column corresponds to the ratio of the saturation pressure of dinitrogen to the saturation pressure of the main chemical species indicated in the left column, at 126 K.

[0086] Thus, it is observed that the saturated vapor pressure at any temperature below 126 K of the or each main chemical species is lower than the saturated vapor pressure of nitrogen at the temperature below 126 K in a ratio of 242857 for CO2 and 15455 for R1234ze(E).

[0087] With reference to the, a cutaway view of a ship 70, for example a hydrogen carrier intended to transport liquefied hydrogen, shows a tank 71, sealed and insulated, of generally prismatic shape mounted in the double hull 72 of the ship. The wall of the tank 71 comprises a primary sealed barrier intended to be in contact with the liquefied gas, preferably hydrogen, contained in the tank, a secondary sealed barrier arranged between the primary sealed barrier and the double hull 72 of the ship, and two insulating barriers arranged respectively between the primary sealed barrier and the secondary sealed barrier and between the secondary sealed barrier and the double hull 72.

[0088] In a manner known per se, loading / unloading pipelines 73 arranged on the upper deck of the ship can be connected, by means of appropriate connectors, to a maritime or port terminal to transfer a cargo of liquefied gas from or to the tank 71.

[0089] The represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipeline 76 and an onshore installation 77. The loading and unloading station 75 is a fixed offshore installation comprising a mobile arm 74 and a tower 78 which supports the mobile arm 74. The mobile arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading / unloading pipelines 73. The orientable mobile arm 74 adapts to all vessel sizes. A connecting pipe, not shown, extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the ship 70 from or to the onshore installation 77. The latter comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the underwater pipe 76 to the loading or unloading station 75.The subsea pipeline 76 allows the transfer of liquefied gas between the loading or unloading station 75 and the onshore installation 77 over a long distance, for example 5 km, which makes it possible to keep the vessel 70 at a great distance from the coast during loading and unloading operations.

[0090] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the onshore installation 77 and / or pumps equipping the loading and unloading station 75 are used.

[0091] Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0092] The use of the verb "comprise", "comprise" or "include" and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

[0093] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

A method for evacuating an intermediate space in a sealed and thermally insulated tank (1, 111), the sealed and thermally insulated tank (1, 111) comprising an external sealed wall (11, 110), an internal sealed wall (26, 126) located at a distance from an inner side of the external sealed wall (11, 110) and defining an internal space (13) intended to contain liquefied gas, and an intermediate space (30, 130) located between the external sealed wall (11, 110) and the internal sealed wall (26, 126), the method comprising the steps of: - replacing a gaseous phase present in the intermediate space (30, 130) with a replacement gaseous phase at a first temperature, the first temperature being greater than 273 K, the replacement gaseous phase consisting of one or more principal chemical species, and optionally one or more residual chemical species,the replacement of the gaseous phase comprising the step of injecting the replacement gaseous phase into the intermediate space (30, 130) at a first pressure, the first pressure in the intermediate space being less than 500 kPa absolute, in which the principal chemical species or species is in the gaseous state at the first temperature and at a partial pressure less than the first pressure, in which the principal chemical species or species has a saturated vapor pressure at any temperature less than 126 K less than the saturated vapor pressure of nitrogen at said temperature less than 126 K, the temperature of the internal space (13) being greater than 273 K, then lowering the pressure in the intermediate space (30, 130) to an absolute pressure less than a pressure threshold, and cooling the sealed and thermally insulated vessel (1,111) by injecting a fluid at a second temperature below 273K into the internal space (13) of the sealed and thermally insulated tank (1, 111), in which the pressure threshold is below the triple point of said or each principal chemical species, to cause said or each principal chemical species to condense into solid phase upon cooling of the sealed and thermally insulated tank (1, 111), and in which the residual chemical species is at a partial pressure below 0.1 kPa. Vacuuming method according to claim 1, wherein the first pressure is less than 110 kPa absolute. Vacuum packing method according to claim 1 or 2, wherein the pressure threshold is less than 1 kPa, preferably less than 0.1 kPa. A vacuuming process according to any one of the preceding claims, wherein said saturated vapor pressure at any temperature below 126 K of the or each principal chemical species is less than the saturated vapor pressure of nitrogen at the temperature below 126 K in a ratio of less than 1 / 10, preferably a ratio of less than 1 / 1000, even more preferably a ratio of less than 1 / 10000. A vacuum-sealing process according to any one of the preceding claims, wherein the residual chemical species or species is at a partial pressure of less than 10 Pa, preferably less than 1 Pa. A vacuum packing method according to any one of the preceding claims, wherein said or each principal chemical species is selected from: carbon dioxide and trans-1,3,3,3-Tetrafluoropropene. A vacuum sealing process according to claim 6, wherein the replaced gaseous phase comprises carbon dioxide as the sole principal species. A vacuuming method according to any one of the preceding claims, wherein the replacement of the gaseous phase present in the intermediate space (30, 130) comprises: aspirating said gaseous phase present in the intermediate space (30, 130) outwards from the outer sealed wall (11, 110) until the absolute pressure in the intermediate space (30, 130) is less than a second pressure threshold, wherein the second pressure threshold is less than 20 kPa, preferably less than 10 kPa, even more preferably less than 1 kPa, and then injecting the replacement gaseous phase into the intermediate space (30, 130). A vacuuming method according to claim 8, wherein the steps of aspirating the gaseous phase present in the intermediate space (30, 130) and injecting the replacement gaseous phase are carried out repeatedly. A vacuuming method according to any one of claims 1 to 7, wherein the replacement of the gaseous phase present in the intermediate space (30, 130) comprises simultaneously aspirating said gaseous phase present in the intermediate space (30, 130) to the outside of the external sealed wall (11, 110) and injecting the replacement gaseous phase into the intermediate space (30, 130), in order to carry out a sweep of the intermediate space (30, 130) with the replacement gaseous phase. Vacuum packing method according to any one of the preceding claims, wherein the first temperature is greater than 330 K, preferably greater than 373.15 K. Vacuuming method according to any one of the preceding claims, wherein the cooling of the sealed and thermally insulated tank (1, 111) is carried out by spraying the fluid into the internal space of the sealed and thermally insulated tank (1, 111). Vacuuming method according to any one of the preceding claims, wherein the cooling of the sealed and thermally insulated tank (1, 111) is carried out by filling the internal space (13) of the sealed and thermally insulated tank (1, 111) via a filling line opening into a bottom part of the sealed and thermally insulated tank (1, 111). A vacuum sealing method according to any one of the preceding claims, wherein the fluid is liquid hydrogen. A vacuum packing method according to any one of the preceding claims, wherein the sealed and thermally insulating vessel (1) comprises a secondary sealed membrane situated between the outer sealed wall and the inner sealed wall, the intermediate space being formed between the secondary sealed membrane and the inner sealed wall, the inner sealed wall being a primary sealed membrane, wherein the intermediate space comprises a primary thermally insulating barrier supporting the primary sealed membrane. A sealed and thermally insulating tank comprising an outer sealed wall, an inner sealed wall (126, 26) located at a distance from an inner side of the outer sealed wall (11, 110) and defining an internal space (13) intended to contain liquefied gas, and an intermediate space (30, 130) located between the outer sealed wall (11, 110) and the inner sealed wall (26, 126), wherein the intermediate space (30, 130) comprises a gaseous phase, the gaseous phase being composed of one or more principal chemical species, and optionally one or more residual chemical species, wherein the principal chemical species or species has a saturated vapor pressure at any temperature below 126 K lower than the saturated vapor pressure of nitrogen at said temperature below 126 K, wherein the gaseous phase in the intermediate space (30, 130) is at an absolute pressure below a pressure threshold,said pressure threshold being lower than the triple point of said principal chemical species, and wherein the residual chemical species is at a partial pressure of less than 0.1 kPa. Tank according to the preceding claim, in which the internal space (13) contains liquefied gas, the liquefied gas having a temperature below 273 K. Tank according to the preceding claim, in which the internal space (13) contains liquid hydrogen. Tank according to any one of claims 16 to 18, wherein said or each principal chemical species is selected from: carbon dioxide and trans-1,3,3,3-Tetrafluoropropene. Tank according to any one of claims 16 to 18, wherein carbon dioxide is the sole principal species of the gaseous phase. Tank according to any one of claims 16 to 20, wherein the sealed and thermally insulating tank (1) comprises a secondary sealed membrane (24) located between the external sealed wall (11) and the internal sealed wall (26), the intermediate space (30) being formed between the secondary sealed membrane (24) and the internal sealed wall (26), the internal sealed wall (26) being a primary sealed membrane, wherein the intermediate space (30) comprises a primary thermally insulating barrier (25) supporting the primary sealed membrane (26).

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