SEALED AND INSULATING TANK FOR THE STORAGE AND / OR TRANSPORT OF A LIQUEFIED GAS

Description

Domaine technique

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

[0002] Known from the prior art is a fixed tank for storing liquefied hydrogen, according to the « Boiler and Pressure Vessel Code » (BPVC) of the " American Society of Mechanical Engineers » (ASME), which consists of two rigid, self-supporting, watertight shells nested inside each other. Due to the great thickness of the two shells, the manufacture of a large capacity tank using this technique presents a very high material cost and manufacturing difficulties. Indeed, such a tank requires significant human mobilization in order to manufacture it and to carry out quality control, particularly of the welding points, which significantly increases the manufacturing cost of the tank.

[0003] US-A-4050609 discloses a storage tank for liquefied gas of spherical shape which successively comprises from the inside to the outside: an internal, sealed, self-supporting tank, the internal tank having an inner surface intended to be in contact with the liquefied gas and an outer surface, an insulating barrier covering the outer surface of the internal tank, the insulating barrier being fixed to the internal tank, an outer waterproof membrane covering an outer surface of the insulating barrier and fixed to the insulating barrier.

[0004] As an exterior waterproof membrane, US-A-4050609 uses an aluminum foil glued to a plywood sheet of an insulating block, as well as fiberglass fabric connections. However, this exterior waterproof membrane is fragile and liable to tear at the fiberglass fabric connections covering the studs. A vacuum seal of the insulating barrier is therefore not an option.

[0005] Document JPS52103023A discloses a sealed and insulating tank. Résumé

[0006] One idea underlying the invention is to provide a sealed and insulating tank having a double sealing barrier to confine the liquefied gas and which is suitable for offering high thermal insulation performance for storing a very cold product, for example liquid dihydrogen at ambient pressure. Another idea underlying the invention is to provide a sealed and insulating tank which can be manufactured at a competitive cost, including with a very large capacity.

[0007] For this, according to one embodiment, the invention provides a sealed and insulating tank for the storage and / or transport of a liquefied gas, the tank comprising successively from the inside to the outside: an internal, sealed and self-supporting tank, the internal tank having an internal surface intended to be in contact with the liquefied gas and an external surface, an insulating barrier covering the external surface of the internal tank, the insulating barrier being fixed to the internal tank, an external waterproof membrane covering an external surface of the insulating barrier, the external waterproof membrane comprising a metal sheet provided with bellows or corrugations in order to allow elastic deformation, the external waterproof membrane being fixed to the insulating barrier or the internal tank, in which an intermediate space located between the internal tank and the external waterproof membrane contains a gaseous phase under negative pressure in order to press the external waterproof membrane against the external surface of the insulating barrier

[0008] Thanks to these characteristics, it is possible to create a more or less deep vacuum in the insulating barrier in order to increase the thermal insulation performance of the insulating barrier. In addition, the outer waterproof membrane is configured with bellows or corrugations which make it possible to absorb dimensional variations by elastic deformation without the risk of tearing the outer waterproof membrane. These dimensional variations can in particular be caused by the thermal contraction of the tank during cooling by filling with a cold liquid and by the evacuation of the intermediate space containing the insulating barrier, namely by the compression forces generated by the difference between atmospheric pressure and the pressure prevailing in the intermediate space.

[0009] Furthermore, because the outer membrane covers one surface of the insulating barrier, the sizing of the outer membrane is not dictated by the pressure resistance of the cargo, nor by the atmospheric pressure nor by the depression of the gas phase of the interspace. In other words, a very thin membrane can be used. In addition, such a tank makes it possible to reduce the pressure forces seen by the internal tank. Indeed, the pressure forces seen by the internal tank are, for example, reduced by 100 kPa compared to the situation that would exist if the atmospheric pressure were not transferred to the external surface of the internal tank.

[0010] According to particular embodiments, the sealed and insulating tank has one or more of the characteristics described below taken in isolation or in any technically possible combination(s) which fall within the scope of the claims. Brève description des figures

[0011] 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. [ Fig.1 ] There figure 1 is a schematic sectional view representing a sealed and insulating tank according to a first embodiment. Fig. 2 ] There figure 2 is a view analogous to the figure 1 representing a sealed and insulating tank according to a second embodiment. Fig. 3 ] There figure 3 is a perspective view of a corrugated metal sheet suitable for use as an exterior waterproof membrane. Fig.4 ] There figure 4 is a schematic sectional view showing an insulating block that can be used to make an insulating barrier. Fig. 5 ] There figure 5 is a perspective cutaway view of a tank wall according to another embodiment. Fig. 6 ] There figure 6 is a view analogous to the figure 1 representing a watertight and insulating tank equipped with support feet. Fig. 7 ] There figure 7 is a view analogous to the figure 1 representing a watertight and insulating tank equipped with hangers. Fig. 8 ] There figure 8 is a perspective cutaway view of a tank wall according to another embodiment. Fig. 9 ] There figure 9 is a view analogous to the figure 1 representing a sealed and insulating tank equipped with a lattice of internal stiffeners. Fig.10 ] There figure 10 is a schematic sectional view representing a sealed and insulating tank according to another embodiment. Fig.11 ] There figure 11 is a schematic perspective view of a vessel having a sealed and insulating tank as a fuel tank. Fig. 12 ] There figure 12 is a sectional view of a tank wall provided with a support foot. Fig. 13 ] There figure 13 represents a mechanical coupler that can be used in the tank wall according to one embodiment. Fig. 14 ] There figure 14 represents a sectional view of an insulating barrier retained by the mechanical coupler of the Fig. 13 according to a first embodiment. [ Fig. 15 ] There figure 15 is a view analogous to the Fig. 14 according to a second embodiment. Description des modes de réalisation

[0012] Several embodiments of a sealed and insulating tank for the storage and / or transport of a liquefied gas will be described. In the figures, identical reference numbers designate similar or identical elements.

[0013] The sealed and insulating tank can have different shapes, for example a prismatic shape with flat facets, as in most of the figures below, or a spherical shape, or a cylindrical shape whose directrix curve can be circular or polygonal. In the case of a cylindrical tank, the axial ends of the tank can be closed by flat walls or by hemispherical walls. The sealed and insulating tank can also have a bilobed shape, or another shape.

[0014] As illustrated for example on the figures 1 et 2 , tank 1 comprises successively from the inside to the outside: an internal tank 2, sealed and self-supporting, the internal tank 2 having an interior surface 3 intended to be in contact with the liquefied gas and an exterior surface 4, an insulating barrier 5 covering the exterior surface 4 of the internal tank 2, the insulating barrier 5 being fixed to the internal tank 2, and an exterior waterproof membrane 6 covering an exterior surface 7 of the insulating barrier 5.

[0015] The outer waterproof membrane 6 comprises a metal sheet provided with bellows or corrugations 8 in order to allow elastic deformation. The outer waterproof membrane 6 is fixed on the insulating barrier 5.

[0016] An intermediate space located between the internal tank 2 and the external waterproof membrane 6 contains, in addition to the insulating barrier 5, a gaseous phase under depression in order to press the external waterproof membrane 6 against the external surface 7 of the insulating barrier 5.

[0017] The inner tank 2 is self-supporting and delimits an interior space 9 which directly contains the cargo of liquefied gas. For this purpose, techniques similar to those used for type C tanks within the meaning of the IGC code of the International Maritime Organization can be used. However, unlike a type C tank, the inner tank 2 has a single wall in the thickness direction, and not a double wall.

[0018] The internal tank 2 can be designed with a very different capacity depending on the requirements of the intended application, for example a capacity between approximately 10 3< m 3< and 10 5< m 3< , or even more.

[0019] According to one embodiment, the internal tank may comprise a metal shell having a thickness greater than 10 mm, or even greater than 20 mm. Preferably this thickness is less than 50 mm.

[0020] The internal tank can be manufactured from materials chosen from: non-alloy and low-alloy steels, stainless steels, low thermal expansion coefficient nickel steel alloys, for example Invar ®< , and low thermal expansion coefficient manganese steel alloys, aluminum.

[0021] Preferably, the internal tank is sized to withstand a relative internal pressure greater than 200 kPa, or even greater than 1000 kPa. Such sizing makes it possible to store the liquefied gas under pressure and therefore to increase the storage duration without steam escaping.

[0022] For this, according to one embodiment, internal stiffeners are fixed on the inner surface 3 of the internal tank 2.

[0023] The stiffeners serve to increase the pressure resistance of the internal tank 2. They can be made in different ways. According to one embodiment, the internal stiffeners comprise projecting ribs on the inner surface 3. According to one embodiment, when the tank is parallelepipedal in shape, the ribs in the corners form an arc-shaped structure facing the inside of the internal tank 2.

[0024] According to one embodiment, for example illustrated in the figure 9 , the internal stiffeners comprise rods 11 which extend between opposite sides of said inner surface 3 so as to form a lattice structure 10.

[0025] Examples of such a lattice structure 10 are described for example in publication WO-A-2020021212.

[0026] Unlike a rigid double-jacketed tank mentioned in the introduction, the outer waterproof membrane 6 is not self-supporting and comprises a metal sheet whose thickness is much less than that of the internal tank 2. According to one embodiment, the thickness of the outer waterproof membrane 6 is less than 2 mm, for example equal to 1 or 1.5 mm.

[0027] The outer waterproof membrane 6 can be made of different metals. According to one embodiment, the metal sheet is made of an alloy chosen from non-alloy and low-alloy steels, stainless steels, nickel steel alloys with a low coefficient of thermal expansion, and manganese steel alloys with a low coefficient of thermal expansion.

[0028] In particular, the metal sheet can be made of Invar ®< , that is to say an alloy of iron and nickel whose coefficient of expansion is typically between 1.2.10 -6< K -1< and 2.10 -6< K -1< for an alloy comprising approximately 64% iron and 36% nickel, or in an iron alloy with a high manganese content whose coefficient of expansion is typically of the order of 7 to 9.10 -6< K -1< .

[0029] The metal sheet from which the outer waterproof membrane 6 is formed is provided with bellows or corrugations 8. These bellows or corrugations 8 may project towards the inside of the tank 1 as on the figure 1 or towards the outside of the tank 1 as on the figure 2 Bellows or undulations going alternately in both directions could also be used.

[0030] The bellows or undulations 8 allow elastic deformation of the outer waterproof membrane 6. Thus, the outer waterproof membrane 6 has an elastic deformation capacity allowing it to follow the movements due in particular to the thermal contraction of the internal tank. According to one embodiment, the outer waterproof membrane 6 has an elastic deformation capacity greater than 0.2%, preferably between 0.2 and 1.8% at room temperature in at least one direction perpendicular to the thickness, preferably in any direction perpendicular to the thickness. The deformation capacity of the outer waterproof membrane 6 is calculated on the basis of the deformation of the internal tank 2, therefore by multiplying the coefficient of thermal expansion of the internal tank 2 by the temperature variation in service.For example, an elastic deformation capacity of 0.3% can correspond to the coefficient of expansion of steel which is 11*10 -6< mm / mm.K multiplied by 273 K.

[0031] For this purpose, the outer waterproof membrane 6 may comprise a series of parallel corrugations or preferably two series of parallel corrugations, the two series having respective directions that are intersecting or perpendicular in a mean plane of the metal sheet. A metal sheet plate 15 comprising the two series of corrugations is shown for illustrative purposes in figure 3 . The metal sheet plate 15 is for example made of 1.2 mm thick stainless steel. The corrugations can be obtained by bending.

[0032] According to this embodiment, the outer waterproof membrane 6 is corrugated and comprises a first series of parallel corrugations 16 and flat portions 18 located between the parallel corrugations and resting on the insulating barrier 5, the parallel corrugations 16 being arranged parallel to a first direction.

[0033] According to embodiments, the undulations of the first and / or second series of undulations may be continuous or discontinuous.

[0034] According to this embodiment, the outer waterproof membrane 6 further comprises a second series of parallel corrugations 17 and flat portions 18 located between the parallel corrugations 17 and resting on the insulating barrier 5, the parallel corrugations 17 being arranged perpendicular to the first direction.

[0035] The outer waterproof membrane 6 can be produced over the entire necessary extent by assembling in a watertight manner, by welding with overlap, a plurality of the metal sheet plates 15. This produces undulations which extend continuously from one sheet plate to the next over the entire surface covered by the outer waterproof membrane 6.

[0036] Alternatively, corrugations may be formed discontinuously, for example by stamping. Examples of a metal membrane with discontinuous corrugations are for example available in publication JPS55139597.

[0037] Furthermore, the metal sheet plate 15 is generally flat and is suitable for a flat face of a polyhedral tank. It is understood that the metal sheet can be curved according to one or more radii of curvature depending on the geometry of the tank wall to be covered, which can be, for example, spherical or cylindrical. The corrugations 16 and / or 17 can therefore follow curved guidelines.

[0038] According to one embodiment, the outer waterproof membrane 6 has a generally spherical shape and the first direction, corresponding for example to the parallel undulations 17, is a meridian direction. According to one embodiment, the outer waterproof membrane 6 has a generally cylindrical shape and the first direction, corresponding for example to the parallel undulations 17, is an axial direction. According to one embodiment, the outer waterproof membrane 6 has a generally prismatic or parallelepipedal shape and the first direction, corresponding for example to the parallel undulations 17, is a longitudinal direction.

[0039] Embodiments of the insulating barrier 5 will be presented below. The insulating barrier 5 is fixed to the internal tank 2 and the external waterproof membrane 6 is fixed to the insulating barrier 5. The insulating barrier 5 is sized to withstand a vacuum with a certain degree of deformation, which must not exceed the elastic elongation capacity of the external waterproof membrane 6. The insulating barrier 5 preferably covers the entire external surface 4 of the internal tank 2.

[0040] Different structures and materials can be used for this. According to embodiments, the insulating barrier 5 comprises a material chosen from: polymer foams, for example polyurethane, polyvinyl, polypropylene or polyethylene foams, reinforced or not with fibers, melamine foam (also called BASOTECT foam); mineral wools, polyester or cellulose wadding, for example glass wool, rock wool, perlites, pyrogenic silicas, compacted silicas and aerogels.

[0041] According to one embodiment, the insulating barrier 5 is made of a material chosen from mineral wools, polyester wadding and cellulose wadding. For example, these materials have a thickness of between 200 and 400 mm, preferably between 200 and 300 mm.

[0042] Such insulating materials may be deposited directly onto the outer surface 4 of the inner tank 2 without prior conditioning. For example, glass wool or polyester wadding or cellulose wadding may be deposited directly onto the outer surface 4 of the inner tank 2, for example in the form of parallel strips. According to another example, the polymer foam could be polymerized directly in situ over the entire outer surface 4 of the inner tank 2.

[0043] According to one embodiment, the strips of glass wool or wadding are linked together by sewing, for example with glass, composite or plastic threads.

[0044] According to one embodiment, the insulating barrier 5 is pre-compressed in the thickness direction between the internal reservoir 2 and the external waterproof membrane 6. This pre-compression can be applied by mechanical couplers described below.

[0045] Particularly when the insulating barrier 5 is made of compressible materials such as mineral wool, polyester wadding and cellulose wadding, the pre-compression stress makes it possible to better support the external waterproof membrane 6. It is for example between 0.1 MPa and 0.2 MPa.

[0046] Pre-compression means a stress that exists before the intermediate space is depressurized, which can add additional compression of the insulating barrier 5 via the outer waterproof membrane 6.

[0047] Modular manufacturing of the insulating barrier 5 can facilitate the standardization of insulation installation methods.

[0048] According to embodiments, the insulating barrier 5 comprises heat-insulating elements juxtaposed on the outer surface 4 of the internal tank 2.

[0049] In one embodiment, illustrated for example in figure 4 , a heat-insulating element 20 comprises: a first plate 21 adjacent to the outer surface 4 of the inner tank 2, a second plate 22 parallel to the first plate 21 and spaced from the first plate 21 in a thickness direction of the heat-insulating element 20, the second plate 22 being adjacent to the outer waterproof membrane 6 and a thermal insulation lining 23 arranged between the first plate and the second plate.

[0050] This thermal insulation lining comprises, for example, a polymer foam having a density sufficient to withstand the small compression force linked to the pressure difference between the ambient atmosphere and the intermediate space and to take into account a safety margin. According to one embodiment, the density is between 40 kg / m 3 and 90 kg / m 3, preferably between 40 kg / m 3 and 70 kg / m 3, for example equal to 50 kg / m 3. It may be, for example, a polyurethane, polyvinyl, or polyethylene or polypropylene foam, reinforced or not with glass fibers.

[0051] Plates 21 and 22 can be made of plywood or composite material. They can be glued to the thermal insulation trim 23.

[0052] The heat-insulating elements juxtaposed with each other may have inter-panel spaces. It is then necessary to insert joints in the inter-panel spaces in order to ensure the continuity of the insulating barrier. The joints are for example composed of glass wool. In other words, in the tank according to the invention, the insulating barrier 5 may have a continuity of material. The continuity of material is ensured by insulating materials, such as thermal insulation lining. The smallest space is filled so that no space is present in this barrier. The insulating barrier 5 is thus continuous in all directions, that is to say in the direction of thickness of the tank and perpendicular to this direction. This continuity, in directions perpendicular and parallel to the surface of the tank, is at least present on one layer of the insulation.

[0053] In one embodiment, a heat-insulating element includes a thermal insulation lining, for example made of the aforementioned materials, arranged in the form of a layer parallel to the outer surface of the inner tank. The insulation lining is for example perlite, silica aerogels or their mixtures.

[0054] In one embodiment, load-bearing elements rise through the thickness of said thermal insulation lining to take up forces. In an example applicable to the heat-insulating element 20 illustrated in figure 4 , the load-bearing elements are arranged between the first plate 21 and the second plate 22, and the thermal insulation lining 23 is arranged between the load-bearing elements. When they are present, the density of the thermal insulation lining 23 can be reduced since the load-bearing elements take up the forces at least in part.

[0055] In another embodiment, for example illustrated in figure 5 , the heat-insulating element is produced in the form of a box 40 comprising the first plate 41, the second plate 42 and side plates 43 extending between the first plate 41 and the second plate 42 to enclose an interior space of the box 40. The interior space of the box 40 is filled with said thermal insulation lining.

[0056] Since the box 40 takes up the compressive forces, the thermal insulation lining (not shown) can be any non-structural material, for example a powder such as perlite, glass wool or the like.

[0057] According to one embodiment, the load-bearing elements comprise load-bearing partitions segmenting said interior space into a plurality of compartments filled with the thermal insulation lining and keeping the first plate 41 at a distance from the second plate 42.

[0058] Further details on the manufacture of such an insulating barrier can be found in publication WO-A-2017064426.

[0059] The rigid elements of the insulating barrier 5, such as the boxes 40, the load-bearing elements or the plates 21 and 22, can be made of plywood or composite material.

[0060] According to one embodiment, the thickness of the insulating barrier is greater than 200 mm, preferably between 200 mm and 800 mm.

[0061] Different solutions are possible for fixing the insulating barrier to the internal tank.

[0062] According to one embodiment, the insulating barrier 5 is fixed to the external surface 4 of the internal tank 2 by gluing, preferably via beads of mastic.

[0063] Beads of mastic 45 which can be used to glue the box 40 to the outer surface 4 are for example shown in figure 5 . Such mastic beads also make it possible to correct any possible flatness defects in the external surface 4.

[0064] According to another embodiment, the outer surface 4 of the internal tank 2 carries a plurality of mechanical couplers, and the insulating barrier 5 is fixed to the outer surface 4 of the internal tank 2 by said mechanical couplers.

[0065] Such mechanical couplers are particularly suitable for use with juxtaposed heat-insulating elements. Thus, the figure 5 illustrates mechanical couplers 35 arranged at the corners of the heat-insulating elements 40 and respectively of the boxes 40. Such a mechanical coupler can retain the heat-insulating element by one or other zone thereof, for example at the level of a bottom plate or a cover plate. Thus, on the figure 5 the mechanical coupler 35 cooperates with a cleat 36 resting on the plate 41. Other mechanical couplers can be used, for example the couplers described in FR-A-2798902.

[0066] As visible for example on the figure 5 , mechanical couplers may be used in combination with bonding of the insulating barrier 5. It may also be noted that, when mechanical couplers are used, bonding is not essential. Beads of mastic 45 may be used to compensate for flatness defects in the outer surface 4.

[0067] A mechanical coupler 135 according to another embodiment is shown in the figures 13 à 15 The mechanical coupler 135 comprises a rod 138 passing through the insulating barrier 5 in the direction of the thickness of the insulating barrier and an end piece 137 which is fixed to one end of the rod 138 opposite the internal reservoir and which bears on an external surface of the insulating barrier 5. Advantageously, the external waterproof membrane 6 is attached to the end piece 137.

[0068] More specifically, the mechanical coupler 135 comprises a rod 138, and a first end piece 136 and a second end piece 137 arranged at the two ends of the rod 138. The fixing of the rod 138 to the first and second end pieces 136, 137 is for example carried out by screwing or by clipping.

[0069] The mechanical coupler is, for example, made from a metallic material. To limit thermal conduction, it is preferable to use a non-metallic material, for example a composite material, particularly for the rod 138.

[0070] The first end piece 136 is fixed on the outer surface 4 of the internal tank 2 and carries the rod 138. For example, the first end piece 136 is metallic and fixed by welding.

[0071] The second end piece 137 is fixed to the other end of the rod 138 and has a wider section than the rod 138 to bear on the insulating barrier 5. Thus, the mechanical coupler 135 can exert pressure on the insulating barrier 5 via the second end piece 137, which comprises for example a plate or a washer. The second end piece 137 is for example made of composite or plastic material.

[0072] According to another embodiment, the second end piece 137 is metallic, which also allows the outer waterproof membrane 6 to be welded to it. Thus, the mechanical coupler 135 can be used to retain both the insulating barrier 5 and the outer waterproof membrane 6.

[0073] There figure 14 illustrates the cooperation of the mechanical coupler 135 with the insulating barrier 5. In this embodiment, the mechanical coupler 135 passes through a heat-insulating element 140 of the insulating barrier 5, which is for example a block of insulating foam or a strip of glass wool or polyester wadding.

[0074] There figure 15 illustrates the cooperation of the mechanical coupler 135 with the insulating barrier 5 in a second embodiment. Here, the mechanical coupler 135 passes through a heat-insulating element 141 located between two heat-insulating elements 145. The heat-insulating element 141 has on each lateral portion a shoulder 142 pressing on a corresponding projection of the adjacent heat-insulating elements 145 in order to press the adjacent heat-insulating elements 145 against the external surface 4 of the internal tank 2.

[0075] It goes without saying that the mechanical coupler 135 is present in multiple copies arranged appropriately to retain the entire insulating barrier 5 on the internal tank 2, for example in the form of parallel rows of couplers or in the form of a square or rectangular mesh network or the like. According to one embodiment, the mechanical couplers are spaced apart by a pitch of between 0.5 m and 2 m. The mechanical couplers may or may not serve to retain the external waterproof membrane 6. In one embodiment, some of the mechanical couplers fulfill this function and others do not.

[0076] There are various possibilities for retaining the external waterproof membrane 6 on the insulating barrier 5.

[0077] According to one embodiment, a said heat-insulating element carries, on an external face opposite the internal tank, at least one metal part intended to fix the external waterproof membrane to the insulating barrier, by welding to said metal part.

[0078] This embodiment is illustrated for example on the figure 5 where metal anchor strips 46 are fixed on the cover plate 42 of the boxes 40.

[0079] According to a variant not shown, the anchoring of the external waterproof membrane 6 is carried out using insulating foam pads having a first end fixed to the external surface 4 of the internal tank 2. The insulating foam pad comprises a metal plate on a second end, opposite the first end, the metal plate being intended to fix the external waterproof membrane 6. For example, projecting threaded rods are welded to the external surface 4 of the internal tank 2 and the insulating foam pads are fixed to the threaded rods, for example by screwing into a tapped hole of complementary shape.

[0080] As indicated, the insulating barrier 5 is located in an intermediate space which is sealed between the internal tank 2 and the external waterproof membrane 6 and which contains a gaseous phase in depression. This depression, in other words a partial vacuum, makes it possible to lower the heat transfer in the insulating barrier 5 and to increase the thermal insulation performance.

[0081] According to one embodiment, the gas phase under depression has an absolute pressure of less than 1 kPa (10 mbar), preferably 0.1 kPa (1 mbar) at a temperature of 15°C.

[0082] The depression of the gas phase can for example cause the outer waterproof membrane 6 to exert an additional compression of approximately 0.1 MPa on the insulating barrier 5.

[0083] Given its low thickness, the outer waterproof membrane 6 should not be used to support or suspend the tank 1.

[0084] Thus, according to one embodiment, the tank 1 comprises a support system intended to support the tank in an installation, the support system comprising at least one support element having an internal portion fixed to the internal tank 2 and an external portion extending outside the external waterproof membrane 6, said support element extending through a thickness of the insulating barrier 5 and passing in a sealed manner through the external waterproof membrane 6.

[0085] According to one embodiment, illustrated for example in the figure 6 , a said support element 50 is fixed to a lower portion of the internal tank 2, and the tank 1 is carried by said support element 50. Thus the installation is for example a floor wall 52 above which the tank 1 is supported by means of one or more support elements 50.

[0086] According to one embodiment, illustrated for example in the figure 7 , a said support element 51 is fixed to an upper portion of the internal tank 2, and the tank 1 is suspended by said support element 51. Thus the installation is for example a ceiling wall 53 under which the tank 1 is suspended by means of one or more support elements 51.

[0087] Except for the positions illustrated in figures 6 And 7 , similar support elements may be located at any suitable location on the inner tank 2. Thus, the tank 1 could also be secured to vertical walls by supports extending horizontally from one or more lateral sides of the inner tank 2.

[0088] There figure 8 illustrates an embodiment of a support foot 60 that can be used to produce the support element 50 or 51. The support foot 60 comprises a base 61 fixed, for example welded, to the outer surface 4 between the heat-insulating elements forming the insulating barrier 5, which are here boxes 40. The base 61 extends through the thickness of the insulating barrier 5 from the outer surface 4 to the height of the external waterproof membrane 6. The base 61 carries a metal sealing plate 62, which makes it possible to seal the entire contour of an opening made in the external waterproof membrane 6 (not shown). According to a variant, the base 61 is formed from an insulating material capable of supporting the metal sealing plate 62, for example wood or fiberglass composite. This embodiment is advantageous in that it makes it possible to reduce thermal bridges that can reduce the quality of the thermal insulation.

[0089] The metal sealing plate 62 carries one or more feet 63 projecting beyond the outer waterproof membrane 6 and enabling it to cooperate with the floor wall 52 or ceiling wall 53, depending on the location of the support foot 60 on the internal tank 2. Further details on the manufacture of such a support foot can be found in the publication WO-A-2017174938.

[0090] There figure 12 illustrates another embodiment of a support system. The support system is a support foot 160 comprising a first internal part 161 and a second external part 163, and a metal sealing plate 162 arranged between them. The first internal part 161 is located between the outer surface 4 of the internal tank 2 and the inner surface of the waterproof membrane 6. The second external part 163 extends from the outer surface 7 of the insulating membrane 6 to an external support 90, for example a floor. The first part 161 is for example a wooden or fiberglass wedge fixed to the internal tank 2 and which extends to the outer waterproof membrane 6. The internal tank 2 rests on the first part 163. Thus, this first part makes it possible in particular to limit thermal bridges through the insulating barrier 5. The second part 163 is a support for example made of metal positioned opposite the first part.Thus, the support foot 160 makes it possible to support the weight or part of the weight of the tank without crushing or deforming the insulation of the insulating barrier 5. The number of support feet as well as the dimensions of the first part 161 and the second part 163 will be chosen with regard to the shape and weight of the tank. When a plurality of support feet 160 are necessary, they may have identical or different dimensions. In a manner not shown, a metal part may be interposed between the part 161 and the shell 2 to better support the weight of the shell 2.

[0091] THE figure 12 also illustrates welding zones 95 for connecting the outer waterproof membrane 6 to the metal sealing plate 162.

[0092] As indicated, the tank 1 can have various shapes. A spherical tank is shown schematically in the figure 10 . The portion 55 of the support elements 50 has been shown in broken lines to clarify that they pass through the thickness of the insulating barrier 5, as already described.

[0093] Such a tank can be used to store various liquefied gases, for example liquefied natural gas, liquefied petroleum gas, ammonia. Preferably, the sealed and insulating tank intended to contain dihydrogen.

[0094] Such a tank may be part of a land-based storage facility, for example for storing hydrogen or LNG, or may be installed in a floating, coastal, or deep-water structure, including an LNG carrier, a floating storage and regasification unit (FSRU), a floating production and remote storage unit (FPSO), and the like. According to one embodiment, the land-based storage facility is intended to supply gas to an electrical or thermal energy production device, for example to supply a city with electricity or heat, or to a network, for example to supply a city with natural gas.

[0095] In particular, in a land, air or sea vehicle, comprising a propulsion or energy production device, the sealed and insulating tank 1 can serve as a fuel tank for the propulsion or energy production device, as illustrated in figure 11 in reference to a ship 70.

[0096] In one embodiment, a transfer system for a combustible liquefied gas comprises the aforementioned vehicle, insulated pipelines arranged to connect the fuel tank of the vehicle to a floating or land-based storage facility and a pump for driving a flow of combustible liquefied gas through the insulated pipelines from the floating or land-based storage facility to the fuel tank.

[0097] In a method of loading a vehicle described above, a combustible liquefied gas is conveyed through insulated pipelines from a floating or land-based storage facility to the vehicle's fuel tank.

[0098] For example, in reference to the figure 11 , the ship 70 comprises the sealed and insulating tank 1, for example of generally prismatic shape, mounted in the hull 72 of the ship.

[0099] In a manner known per se, loading / unloading pipelines arranged on the upper deck of the ship can be connected, by means of transfer lines 73, to a port terminal 75 to transfer a cargo of combustible liquefied gas to the tank 1.

[0100] To generate the pressure necessary for the transfer of liquefied gas, pumps on board the ship 70 and / or pumps fitted to the port terminal 75 are used.

[0101] 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.

[0102] 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.

[0103] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

1. A sealed and insulating tank (1) for storing and / or transporting a liquefied gas, the tank comprising successively, from the inside to the outside: an internal reservoir (2), which is sealed and self-supporting, the internal reservoir having an inner surface intended to be in contact with the liquefied gas, and an outer surface, an insulating barrier (5) covering the outer surface of the internal reservoir, the insulating barrier being attached to the internal reservoir, an outer sealed membrane (6) covering an outer surface of the insulating barrier, the outer sealed membrane comprising a piece of sheet metal the outer sealed membrane being attached to the insulating barrier or the internal reservoir, characterized in that the outer sealed membrane is provided with bellows or corrugations (8) so as to allow elastic deformation, wherein an intermediate space located between the internal reservoir and the outer sealed membrane contains a gas phase under depression in order to press the outer sealed membrane (6) against the outer surface of the insulating barrier (5), wherein the depression consists of a difference between the pressure prevailing inside the intermediate space and the atmospheric pressure.

2. The sealed and insulating tank as claimed in claim 1, wherein the internal reservoir (2) comprises a metal shell having a thickness greater than 10 mm.

3. The sealed and insulating tank as claimed in claim 1 or 2, wherein the internal reservoir (2) is manufactured from materials chosen from: non- and low-alloy steels, stainless steels, steel alloys containing nickel with a low coefficient of thermal expansion, and steel alloys containing manganese with a low coefficient of thermal expansion, aluminum.

4. The sealed and insulating tank as claimed in one of claims 1 to 3, wherein internal stiffeners (11) are attached to the inner surface of the internal reservoir.

5. The sealed and insulating tank as claimed in claim 4, wherein the internal stiffeners (11) include protruding ribs on the inner surface (3).

6. The sealed and insulating tank as claimed in one of claims 1 to 5, wherein the internal reservoir (2) is dimensioned to withstand a relative internal pressure greater than 200 kPa.

7. The sealed and insulating tank as claimed in one of claims 1 to 6, the tank further comprising a support system (50, 51, 60, 160) intended to support the tank in an installation (52, 53), the support system comprising at least one support element (60) having an internal portion (61, 161) attached to the internal reservoir and an external portion (63, 163) extending outside the outer sealed membrane (6), said support element (60) extending through a thickness of the insulating barrier (5) and passing sealingly through the outer sealed membrane (6).

8. The sealed and insulating tank as claimed in claim 7, wherein a said support element (50) is attached to a lower portion of the internal reservoir, and wherein the tank is borne by said support element.

9. The sealed and insulating tank as claimed in claim 7, wherein a said support element (51) is attached to an upper portion of the internal reservoir, and wherein the tank is suspended by said support element.

10. The sealed and insulating tank as claimed in one of claims 1 to 9, wherein the insulating barrier (5) comprises a material chosen from: polymer foam, mineral wool, polyester or cellulose wadding, perlite, fumed silica, compacted silica and aerogels.

11. The sealed and insulating tank as claimed in one of claims 1 to 10, wherein the insulating barrier (5) is made of a material chosen from mineral wool, polyester wadding and cellulose wadding.

12. The sealed and insulating tank as claimed in one of claims 1 to 11, wherein the insulating barrier (5) is pre-compressed in the thickness direction between the internal reservoir (2) and the outer sealed membrane (6).

13. The sealed and insulating tank as claimed in one of claims 1 to 12, wherein the insulating barrier comprises heat-insulating elements (20, 40) juxtaposed on the outer surface of the internal reservoir.

14. The sealed and insulating tank as claimed in claim 13, wherein a heat-insulating element (40) includes a thermal insulation lining arranged in the form of a layer parallel to the outer surface of the internal reservoir.

15. The sealed and insulating tank as claimed in claim 13 or 14, wherein the heat-insulating element is produced in the form of a box (40) comprising the first plate (41), the second plate (42) and side plates (43) extending between the first plate and the second plate to enclose an interior space of the box, the interior space of the box being filled with said thermal insulation lining.

16. The sealed and insulating tank as claimed in one of claims 13 to 15, wherein a said heat-insulating element carries, on an outer face opposite the internal reservoir, at least one metal part (46) intended to attach the outer sealed membrane on the insulating barrier, by welding on said metal part.

17. The sealed and insulating tank as claimed in one of claims 1 to 16, wherein the thickness of the insulating barrier (5) is between 200 mm and 800 mm.

18. The sealed and insulating tank as claimed in one of claims 1 to 17, wherein the outer surface (4) of the internal reservoir bears a plurality of mechanical couplers (35, 135), and wherein the insulating barrier (5) is attached to the outer surface of the internal reservoir by said mechanical couplers (35, 135).

19. The sealed and insulating tank as claimed in claim 18, wherein a said mechanical coupler (135) comprises a rod (138) passing through the insulating barrier (5) in the thickness direction of the insulating barrier and an end piece (137) which is attached to one end of the rod (138) opposite the internal reservoir and which bears on an outer surface of the insulating barrier (5).

20. The sealed and insulating tank as claimed in claim 19, wherein the outer sealed membrane (6) is attached to the end piece (137).

21. The sealed and insulating tank as claimed in one of claims 1 to 20, wherein the thickness of the outer sealed membrane (6) is less than 2 mm.

22. The sealed and insulating tank as claimed in one of claims 1 to 21, wherein the sheet metal is made of an alloy chosen from non- and low-alloy steels, stainless steels, steel alloys containing nickel with a low coefficient of thermal expansion, and steel alloys containing manganese with a low coefficient of thermal expansion.

23. The sealed and insulating tank as claimed in one of claims 1 to 22, wherein the outer sealed membrane (6) is corrugated and comprises a first series of parallel corrugations (16) and portions located between the parallel corrugations and resting on the insulating barrier, the parallel corrugations being arranged parallel to a first direction.

24. The sealed and insulating tank as claimed in claim 23, wherein the outer sealed membrane further comprises a second series of parallel corrugations (17) and flat portions located between the parallel corrugations and resting on the insulating barrier, the parallel corrugations being arranged perpendicular to the first direction.

25. The sealed and insulating tank as claimed in one of claims 23 to 24, wherein the outer sealed membrane (6) has a generally spherical shape and the first direction is a meridian direction, or the outer sealed membrane has a generally cylindrical shape and the first direction is an axial direction, or the outer sealed membrane has a generally parallelepiped shape and the first direction is a longitudinal direction.

26. The sealed and insulating tank as claimed in one of claims 1 to 25, wherein the outer sealed membrane (6) has a capacity for elastic deformation of greater than 0.2%, preferably between 0.2 and 1.8% at ambient temperature in at least one direction perpendicular to the thickness, preferably in any direction perpendicular to the thickness.

27. The sealed and insulating tank as claimed in one of claims 1 to 26, wherein the gas phase under depression has an absolute pressure of less than 1 kPa (10 mbar), preferably 0.1 kPa (1 mbar) at a temperature of 15°C.

28. An onshore storage facility comprising a sealed and insulating tank as claimed in one of claims 1 to 27.

29. A land, air or marine vehicle, in particular a carrier (70), comprising a propulsion or energy production device and a sealed and insulating tank (1) as claimed in one of claims 1 to 27 as a fuel reservoir for the propulsion or energy production device.

30. A use of a sealed and insulating tank (1) as claimed in one of claims 1 to 27, for storing and / or transporting dihydrogen.