Sealed tank

Abstract

The invention relates to a sealed can comprising a can wall (1) comprising: an outer sealing membrane (4) comprising a parallel first series of corrugations (14) and a flat area (15); a spacer block (5) arranged on the flat region and secured to the outer sealing membrane, the spacer block having an outer end positioned against said flat region, a flat inner surface, and a lateral end connecting the outer end to the inner surface, the lateral end comprising a first lateral end, a first lateral end extending parallel to the first series of corrugations and oriented toward a first corrugation in the first series of corrugations, the inner surface including an end portion partially overlying the first corrugation; an inner sealing membrane (6) separated from the outer sealing membrane by the spacer block, the inner sealing membrane comprising a flat portion fastened on an inner surface of the spacer block.

Description

Technical Field

[0001] The present invention relates to the field of sealed tanks, in particular to the field of sealed tanks for storing and / or transporting liquefied gas. Background Art

[0002] Sealed tanks for storing liquefied gas are known in the prior art. Such sealed tanks include, for example, a tank wall having a multilayer structure comprising, in sequence, a primary sealing film intended to be in contact with the product contained in the tank, a primary thermal insulation barrier, a secondary sealing film, and a secondary thermal insulation barrier. Summary of the Invention

[0003] The inventors have discovered that, when storing liquefied gas, known tanks cannot continue to operate safely in all circumstances if the primary sealing membrane is damaged or has defects that allow liquefied gas to enter the intermembrane space. In fact, the element located below the primary membrane of known tanks is made of a material that deteriorates when the element comes into contact with certain liquefied gases.

[0004] Furthermore, in the case of existing tanks, such as those capable of storing liquefied natural gas (LNG), the elements situated below the primary membrane will not necessarily be suitable for contact with another liquefied gas, such as ammonia.

[0005] On the other hand, liquid ammonia is a liquid with a higher density, and therefore, liquid ammonia is heavier than, for example, LNG, and the load transferred to the primary sealing membrane is greater, thereby possibly causing damage to the primary sealing membrane.

[0006] Therefore, there is a real need to design or improve tanks intended to contain liquefied gases, especially when the insulation elements comprise polypropylene or polyurethane foam or plywood, and in particular when the tanks are intended to contain liquefied gases that are incompatible with the underlying insulation elements. In fact, the contact between these elements and certain liquefied gases (for example, ammonia) leads to a significant loss of mechanical strength in these elements.

[0007] It is an object of the present invention to address at least some of the above problems.

[0008] Another object of the present invention is to make a sealed tank capable of containing liquefied gases, in particular gases that are incompatible with certain insulating materials, such as liquid ammonia, which is at about -33°C at atmospheric pressure.

[0009] Another object of the present invention is to provide a method for converting a sealed and insulated tank originally used to store LNG to store another liquefied gas, such as ammonia.

[0010] According to one embodiment, the present invention provides a sealed tank for storing liquefied gas, the sealed tank comprising a tank wall intended to be installed in a load-bearing structure, the tank wall comprising, in a thickness direction of the tank wall:

[0011] - a metallic outer sealing membrane comprising a first series of parallel corrugations and a flat area;

[0012] a spacer block arranged on at least one of said flat areas of the outer sealing membrane and fastened to the outer sealing membrane,

[0013] the spacer block having an outer end, a flat inner surface parallel to the outer end, and lateral ends connecting the outer end to the inner surface, the outer end being positioned against the at least one flat area, the lateral ends including a first lateral end extending parallel to and oriented toward a first corrugation in the first series of corrugations, the inner surface including a first end portion partially overhanging the first corrugation; and

[0014] - a metallic inner sealing membrane intended to be in contact with the liquefied gas, wherein the inner sealing membrane is separated from the outer sealing membrane by a spacer block, the inner sealing membrane comprising at least one flat portion fastened to the inner surface of the spacer block.

[0015] These features enable the spacer blocks to be positioned above the corrugated portion of the outer sealing membrane. This optimizes the transfer of hydrostatic loads to the underlying components and ensures that the inner sealing membrane is satisfactorily supported.

[0016] According to one embodiment, the present invention further provides a method for modifying a sealed tank originally used to store a first liquefied gas, the method comprising:

[0017] fastening the spacer block to at least one flat area of ​​an outer sealing membrane, wherein the outer sealing membrane is a main membrane belonging to a wall of a sealed tank for storing a first liquefied gas, the outer sealing membrane being made of metal and comprising a first series of parallel corrugations; the spacer block comprising an outer end, a flat inner surface parallel to the outer end, and lateral ends connecting the outer end to the inner surface, the outer end being positioned against the at least one flat area, the lateral ends comprising a first lateral end extending parallel to the first series of corrugations and oriented toward a first corrugation in the first series of corrugations, and the inner surface comprising a first end portion partially overhanging the first corrugation; and

[0018] At least one flat area of ​​the metallic inner sealing membrane is fastened to the inner surface of the spacer block so that the inner sealing membrane is separated from the outer sealing membrane by the spacer block.

[0019] The use of this method makes it possible in particular to anchor the spacer block directly on the main membrane belonging to the sealing and insulating tank wall for storing LNG, without having to install a thermal protection between the flat area of ​​the outer sealing membrane and the insulating barrier.

[0020] According to some embodiments, the tank or the method may include one or more of the following features:

[0021] According to one embodiment, the first lateral end extends between the outer end and the inner surface of the spacer block towards the first corrugation.

[0022] According to one embodiment, the flat area of ​​the outer sealing membrane is located between two corrugations of the first series of corrugations.

[0023] According to one embodiment, the first lateral end portion has a concave shape so as to overhang the first corrugated portion.

[0024] These features ensure that the first lateral end cooperates with the shape of the first corrugation at a distance to ensure that the inner surface of the spacer block is properly supported without interacting with the corrugation of the outer sealing membrane, thereby ensuring that the inner sealing membrane is properly supported.

[0025] According to one embodiment, the first lateral end portion does not contact the first bellows portion. Therefore, the first bellows portion can open and close freely without the movement of the first bellows portion being hindered by contact between the spacer block and the first bellows portion. According to one embodiment, the lateral end portion does not contact the bellows portion of the outer sealing membrane.

[0026] According to one embodiment, the spacer blocks are not in contact with the corrugated portion of the outer sealing membrane.

[0027] According to one embodiment, the thickness of the spacer block is smaller than the height of the first series of corrugations in the thickness direction of the tank wall.

[0028] According to one embodiment, the thickness of the spacer block is greater than the height of the first series of corrugations in the thickness direction of the tank wall.

[0029] According to one embodiment, the thickness of the spacer block is between 20 mm and 150 mm.

[0030] According to one embodiment, the outer sealing membrane comprises a second series of corrugations perpendicular to the first series of corrugations.

[0031] According to one embodiment, the lateral ends of the spacer block include second lateral ends, which extend parallel to the second series of corrugations and are respectively oriented towards the first corrugations in the second series of corrugations, and the inner surface includes a second end portion that partially overhangs the first corrugations in the second series of corrugations.

[0032] According to one embodiment, the second lateral end extends between the outer end and the inner surface of the spacer block towards the first corrugation of the second series of corrugations.

[0033] According to one embodiment, a flat area is defined between two corrugations of the first series of corrugations and between two corrugations of the second series of corrugations.

[0034] According to one embodiment, the corrugated portion of the outer sealing membrane protrudes from the flat area towards the inside of the can.

[0035] According to one embodiment, the height of the first series of corrugations is less than the height of the second series of corrugations in the thickness direction of the tank wall. According to one embodiment, the thickness of the spacer block is between the height of the second series of corrugations and the height of the first series of corrugations.

[0036] According to one embodiment, the spacer block includes support ribs and hollow cells, the support ribs being located below the inner surface and between the lateral ends, and the hollow cells being located between the support ribs.

[0037] The spacer block is thus reinforced by the supporting ribs. Furthermore, the hollow cells enable the inner space in the spacer block to be inert, thereby enabling gas molecules to pass between the hollow cells located inside the spacer block and the intermembrane space between the inner and outer sealing membranes.

[0038] According to one embodiment, the supporting ribs are parallel.According to one embodiment, the supporting ribs are connected to each other.

[0039] According to one embodiment, the hollow cell has a rectangular or triangular cross section.

[0040] According to one embodiment, the outer ends of the spacer block are formed by the edges of the lateral ends and / or the end edges of the supporting ribs, and the hollow cells are open at the outer ends of the spacer block.

[0041] The hollow cells thus enable the inner space in the spacer block to be rendered inert, thereby enabling gas molecules to pass between the hollow cells located inside the spacer block and the inter-membrane space located between the inner and outer sealing films.

[0042] According to one embodiment, one of the lateral ends is formed by a lateral edge of the support rib. According to one embodiment, the first lateral end is formed by a lateral edge of the support rib. According to one embodiment, the lateral ends are formed by end edges of the support rib.

[0043] According to one embodiment, the outer end and the lateral end are formed by end edges of the supporting ribs.

[0044] According to one embodiment, the outer end of the spacer block is formed by a flat outer surface parallel to the inner surface.

[0045] These features improve the support provided by the spacer blocks to the inner sealing membrane.

[0046] According to one embodiment, at least one of the lateral end portions comprises a side wall traversed by a through passage. According to one embodiment, the first lateral end portion comprises a side wall traversed by a through passage.

[0047] According to one embodiment, at least one of the lateral ends comprises a plurality of through-going channels.

[0048] According to one embodiment, the lateral end portion comprises a plurality of support elements separated from each other by through-going channels, preferably the support elements are spacers connecting the outer end portion and the inner surface of the spacer block.

[0049] According to one embodiment, the tank further comprises a fastener fastened to a flat area of ​​the outer sealing membrane and protruding toward the inner sealing membrane, and the spacer block is fastened to the fastener. According to one embodiment, the fastener is selected from a metal cylinder or a metal strip. According to a preferred embodiment, the fastener is a metal rod, such as a metal stud.

[0050] According to one embodiment, the fastener is fastened to the outer sealing membrane by welding to the inner surface of the flat area of ​​the outer sealing membrane.According to one embodiment, the fastener is fastened by capacitor discharge welding.

[0051] Thus, fasteners, such as fastening rods, can be fastened directly to the outer membrane without having to penetrate the outer sealing membrane. This embodiment is particularly advantageous when converting sealed and insulated tanks originally used to store LNG to store liquid ammonia. In fact, capacitor discharge welding also prevents the underlying insulation from being damaged by heat, without the need for additional thermal protection.

[0052] According to one embodiment, the spacer block includes a temporary through hole through which the fastening rod can pass and be fastened. According to one embodiment, the spacer block includes a metal cover for closing the temporary fastening hole.

[0053] According to one embodiment, the spacer block includes a retaining surface that cooperates with a nut or clamp mounted on the fastener.

[0054] According to one embodiment, the spacer block is made of a material that is compatible with the liquefied gas intended to be contained in the tank.

[0055] According to one embodiment, the spacer block comprises aluminum or a thermoplastic material.

[0056] According to one embodiment, the composition of the spacer block is similar to that of the thermal insulation barrier. The spacer block comprises, for example, a thermal insulation material such as polyurethane foam or glass wool. Advantageously, the spacer block comprises at least one rigid plate.

[0057] According to one embodiment, the spacer comprises an aluminum alloy, for example, 6082 aluminum alloy. According to one embodiment, the spacer block comprises aluminum accounting for more than 50% of the mass of the spacer. According to one embodiment, the spacer block consists of aluminum.

[0058] These features make the spacer blocks compatible with ammonia, i.e., the spacer blocks are not damaged by contact with liquid or gaseous ammonia, i.e., the physical properties of the spacer blocks, which primarily enable them to support the inner membrane, are not altered by contact with ammonia. Therefore, due to these features, if the inner sealing membrane is damaged and liquid or gaseous ammonia is able to enter the inter-membrane space, the tank including the damaged inner membrane can continue to function without having to drain the tank.

[0059] In particular, a spacer block is considered compatible with liquid or gaseous ammonia if the spacer block can be in contact with the liquid or gaseous ammonia for at least 8 days without compromising the supporting capacity of the spacer block.

[0060] According to one embodiment, the spacer block comprises aluminum and is obtained by extrusion.

[0061] According to one embodiment, the thermoplastic material is selected from the group consisting of: high density polyethylene, polypropylene and high strength polystyrene.

[0062] According to one embodiment, the spacer block made of thermoplastic material comprises fibers, eg long fibers.

[0063] According to one embodiment, the spacer block of composite material is obtained by hot stamping or by injection molding.

[0064] According to one embodiment, the spacer blocks do not comprise insulating material.

[0065] According to one embodiment, the at least one flat area includes a first flat area, the thickness of the spacer block is greater than the height of the first series of corrugations in the thickness direction of the tank wall, the outer end of the spacer block is arranged on at least one second flat area of ​​the outer sealing film, and the spacer block extends above at least one other corrugation in the first series of corrugations located between the first flat area and the second flat area.

[0066] According to one embodiment, the thickness of the spacer block is greater than the height of the second series of corrugations in the thickness direction of the tank wall, the outer end of the spacer block is arranged on at least one other flat area of ​​the outer sealing membrane, and the spacer block extends above another corrugation in the second series of corrugations located between the first flat area and the other flat area.

[0067] Preferably, in this case, the height of the first series of corrugations is smaller than the height of the second series of corrugations in the thickness direction of the tank wall.

[0068] According to one embodiment, the outer end of the spacer block is arranged on at least one second flat area of ​​the outer sealing membrane, and the spacer block extends above at least one other corrugation portion in the first series of corrugations located between the first flat area and the second flat area. The outer end of the spacer block is also arranged on at least one other flat area of ​​the outer sealing membrane, and the spacer block extends above one other corrugation portion in the second series of corrugations located between the first flat area and the other flat area.

[0069] According to one embodiment, the outer ends of the spacer blocks are arranged on n flat areas of the outer sealing membrane, n being a number between 2 and 20, preferably between 2 and 9.

[0070] According to one embodiment, the spacer block extends over 2 to 9 corrugations of the first series of corrugations.

[0071] According to one embodiment, the spacer block extends over 2 to 9 corrugations of the second series of corrugations.

[0072] According to one embodiment, the spacer block extends over two of the first series of corrugations and over two of the second series of corrugations. According to one embodiment, the spacer block extends over two of the first series of corrugations and over three of the second series of corrugations. According to one embodiment, the spacer block extends over three of the first series of corrugations and over two of the second series of corrugations. According to one embodiment, the spacer block extends over three of the first series of corrugations and over three of the second series of corrugations.

[0073] According to one embodiment, the outer end of the spacer block includes a portion having a shape complementary to the corrugations of the first series of corrugations and / or a shape complementary to the corrugations of the second series of corrugations, so as to pass over and at a distance from the corrugations of the first series of corrugations and / or the second series of corrugations. According to one embodiment, the complementary shape is formed by embossing the outer end of the spacer block.

[0074] According to one embodiment, the lateral end portion comprises a third lateral end portion positioned opposite the first lateral end portion, the third lateral end portion extending parallel to the first series of corrugations, and the inner surface comprises a third end portion partially overhanging the second corrugation portion in the first series of corrugations.

[0075] According to one embodiment, the third lateral end extends between the outer end and the inner surface of the spacer block towards the second corrugation of the first series of corrugations.

[0076] According to one embodiment, the inner surface is larger than the outer end in a direction transverse to the first series of corrugations.

[0077] According to one embodiment, the lateral end portions include a fourth lateral end portion positioned opposite the second lateral end portion, the fourth lateral end portion extending between the outer end portion and the inner surface of the spacer block toward a second corrugation in the second series of corrugations such that the inner surface includes a fourth end portion partially overhanging the second corrugation portion.

[0078] According to one embodiment, the inner sealing membrane comprises a first series of corrugations parallel to the first series of corrugations of the outer sealing membrane, and a flat area.

[0079] According to one embodiment, at least one corrugation of the first series of corrugations of the inner sealing membrane is opposite to a first corrugation of the first series of corrugations of the outer sealing membrane in the thickness direction of the tank wall.

[0080] This provides, in particular, a tank in which the thickness of the spacer is smaller than the height of the first corrugation of the outer membrane.

[0081] According to one embodiment, at least one corrugation of the first series of corrugations of the inner sealing membrane is offset in the thickness direction of the tank wall relative to a first corrugation of the first series of corrugations of the outer sealing membrane.

[0082] According to one embodiment, the two roots of the corrugations of the first series of corrugations are positioned against the inner surface of the spacer block.

[0083] According to one embodiment, the pitch of the corrugations in the first series of corrugations of the outer sealing membrane is the same as the pitch of the corrugations in the first series of corrugations of the inner sealing membrane.

[0084] According to one embodiment, the pitch of the corrugations in the first series of corrugations of the outer sealing membrane is different from the pitch of the corrugations in the first series of corrugations of the inner sealing membrane.

[0085] According to one embodiment, the first series of corrugations is a series of small corrugations. In this case, the second series of corrugations may be a series of large corrugations.

[0086] According to another embodiment, the first series of corrugations is a series of large corrugations. In this case, the second series of corrugations may be a series of small corrugations.

[0087] According to yet another embodiment, the first series of corrugations and the second series of corrugations have the same height.

[0088] According to one embodiment, the corrugated portion of the inner sealing membrane protrudes from the flat area towards the inside of the can.

[0089] According to one embodiment, the inner sealing membrane of the sealed canister is intended to be in contact with a liquefied gas, which is: ammonia, dihydrogen, butane, propane or ethane, preferably ammonia.

[0090] According to one embodiment, the inner space in the tank, which is defined by the inner sealing membrane, contains a liquefied gas selected from the group consisting of ammonia, dihydrogen, butane, propane or ethane, preferably ammonia.

[0091] According to one embodiment, the tank wall comprises a metal insert which is fastened to the inner surface of the spacer block and to which the inner sealing membrane is welded. Figures 7 to 10 In particular more details of the geometry or fastening of the metal insert are shown, wherein the thermal insulation barrier should be replaced by a spacer block. According to one embodiment, the inner and outer sealing membranes are made of stainless steel.

[0092] According to one embodiment, the sealed tank is thermally insulated, and the tank wall includes at least one thermal insulation barrier disposed between the outer sealing membrane and the load-bearing structure. For example, the thermal insulation barrier may include an insulating element made of various materials, including materials that are incompatible with ammonia, such as polyurethane foam or glass wool.

[0093] Thus, when the outer sealing membrane is fastened to the thermal insulation barrier, the spacer blocks specifically enable the hydrostatic load to be transmitted to the thermal insulation barrier. Furthermore, the spacer blocks better distribute the load over the underlying thermal insulation barrier. In fact, when the inner sealing membrane is subjected to a load concentrated over a smaller surface area than that of the spacer blocks, the thermal insulation blocks enable the load to be distributed over a larger surface area of ​​the underlying thermal insulation barrier.

[0094] Furthermore, these features enable the inter-membrane space between the inner and outer sealing films to be inertized. Thus, in the event of gas leakage from the inner sealing film into the inter-membrane space, the unwanted gas can escape from the inter-membrane space without damaging the underlying thermal insulation barrier.

[0095] According to one embodiment, the tank wall includes an additional sealing film disposed between the outer sealing film and the load-bearing structure. According to one embodiment, the primary thermal insulation barrier is disposed between the additional sealing film and the outer sealing film, and the secondary thermal insulation barrier is disposed between the additional sealing film and the load-bearing structure. According to one embodiment, the primary thermal insulation barrier and / or the secondary thermal insulation barrier include polyurethane foam or glass wool.

[0096] According to one embodiment, the tank wall comprises a plurality of spacer blocks, each of the plurality of spacer blocks being located on a corresponding flat area of ​​the plurality of flat areas of the outer sealing membrane.

[0097] According to one embodiment, a spacer block is located on each flat area of ​​the outer sealing membrane.

[0098] According to one embodiment, each flat area of ​​the outer sealing membrane is covered by an outer end portion of the spacer block arranged on each flat area.

[0099] The outer end of a given spacer block may lie on multiple flat areas and / or the outer end of a spacer block may lie on a single flat area.

[0100] According to one embodiment, the interior space of the tank has a volume greater than 70,000 m 3 storage capacity.

[0101] According to one embodiment, the above-mentioned tank wall is the bottom wall of the tank when the tank is in the use position.

[0102] According to one embodiment, said tank wall is a side wall of the tank when the tank is in the use position.

[0103] According to one embodiment, the tank comprises a plurality of the above-mentioned walls.

[0104] According to one embodiment, the present invention further provides a storage facility for liquefied gas, the storage facility comprising a bearing structure and the aforementioned sealed tank, wherein the sealed tank is positioned and fastened on the bearing structure.

[0105] According to one embodiment, the first liquefied gas is LNG.

[0106] According to one embodiment of the method, the inner sealing membrane is intended to be in contact with ammonia, dihydrogen, butane, propane or ethane, preferably with ammonia.

[0107] According to one embodiment of the method, a sealed and insulated tank wall for storing the first liquefied gas has a multi-layer structure including, from the outside of the tank, a secondary insulation barrier, a secondary sealing film, a primary insulation barrier, and a primary sealing film.

[0108] According to one embodiment, the spacer block is fastened to the flat area of ​​the outer sealing membrane by a fastener welded to the inner surface of the flat area of ​​the outer sealing membrane and protruding from the outer sealing membrane. The spacer block is fastened to the fastener, and the welding can be performed using a short-cycle welding process (e.g., capacitor discharge welding). According to one embodiment, the fastener is selected from a metal cylinder or a metal strip. According to a preferred embodiment, the fastener is a metal rod, such as a metal stud.

[0109] According to one embodiment, the spacer block comprises at least one metal insert forming at least a portion of the inner surface of the spacer block, the at least one flat portion of the inner sealing membrane being at least partially fastened to the metal insert.

[0110] This enables the inner sealing membrane to be welded to the elements of the spacer block to ensure mechanical strength. The assembly formed by the inner sealing membrane and the spacer block holds the welded elements in place. Furthermore, since the spacer block is hooked to the outer sealing membrane, the welded inner sealing membrane is attached to the structure.

[0111] According to one embodiment, the spacer block comprises a seat accommodating the metal insert, the seat being able to prevent translational movement of the metal insert in the thickness direction.

[0112] This prevents the metal insert from being removed by a simple translational movement.

[0113] According to one embodiment, the inner surface of the spacer block comprises an opening defined by an inner edge of the spacer block.

[0114] According to one embodiment, the metal insert includes at least: a flat central surface, which extends at a first height in a first plane; two end portions parallel to the flat central surface, which extend at a second height in a second plane; and two joining portions joining the flat central surface to the two end portions; so that the flat central surface of the metal insert is flush with the inner surface of the spacer block through the opening.

[0115] According to one embodiment, the inner edge of the opening has a shape complementary to the end of the metal insert.

[0116] This enables the metal insert to be inserted after the spacer block has been mounted on the outer sealing membrane.

[0117] Such tanks may be part of an onshore storage facility or installed on coastal or deepwater floating structures, in particular liquefied gas carriers, floating storage and regasification units (FSRUs) and floating production, storage and offloading (FPSO) units, etc. Such tanks may also be used as fuel tanks on any type of vessel.

[0118] According to one embodiment, the load-bearing structure is located on land or in the seabed, or is part of a vessel.

[0119] According to one embodiment, an onshore installation comprises a load-bearing structure and a tank as described above, the tank being arranged in the load-bearing structure.

[0120] According to one embodiment, a ship for transporting liquefied gas includes a double hull and a tank as described above, the tank being arranged inside the double hull.

[0121] According to one embodiment, the present invention also provides a transport system for liquefied gas, the system comprising the above-mentioned vessel and an insulated pipeline arranged to connect a tank on the vessel to an onshore or floating storage facility.

[0122] According to one embodiment, the transfer system further comprises a pump to drive the flow of the liquefied gas through the insulated pipeline to or from an onshore or floating storage facility to or from a tank on a vessel.

[0123] According to one embodiment, the invention also provides a method for loading or unloading such a vessel, wherein liquefied gas is conducted through insulated piping to or from an onshore or floating storage facility to or from a tank on board the vessel. BRIEF DESCRIPTION OF THE DRAWINGS

[0124] The invention will be better understood and other objects, details, features and advantages of the invention will become clearer in the course of the following description of a number of particular embodiments thereof, given by way of non-limiting illustration only and with reference to the accompanying drawings.

[0125] Figure 1 is a partial schematic cross-sectional view of the wall of the sealed can.

[0126] Figure 2 yes Figure 1 An enlarged cross-sectional view of region I in FIG. 1 shows the tank wall according to the first embodiment.

[0127] Figure 3 is a bottom view of the spacer block according to the first embodiment.

[0128] Figure 4 is a partially exploded perspective view of a tank wall according to the first embodiment.

[0129] Figure 5 is a partial cross-sectional view showing a tank wall according to the second embodiment.

[0130] Figure 6 is a cross-sectional view of a tank wall according to a third embodiment.

[0131] Figure 7 is a top view of a tank wall according to a fourth embodiment.

[0132] Figure 8 is a partial cross-sectional view of a corner area of ​​a tank including a spacer block according to a fifth embodiment.

[0133] Figure 9 is a partial view of a spacer block including a metal insert according to a sixth embodiment.

[0134] Figure 10 is a cross-sectional view of a spacer block according to a sixth embodiment.

[0135] Figure 11 is a partial view of a spacer block including a toothed metal insert according to a seventh embodiment.

[0136] Figure 12is a top view of a spacer block according to a seventh embodiment.

[0137] Figure 13 is a cross-sectional view of a tank on a ship and a loading / unloading dock for the tank. DETAILED DESCRIPTION

[0138] By convention, the terms "outer" and "inner" are used with reference to the inside and outside of a tank to determine the relative position of one element with respect to another.

[0139] See below Figure 1 The wall 1 of the sealed can according to the embodiment is generally described. This wall structure can be used to manufacture substantially all walls of the polyhedral can. In this regard, the terms "upper", "overhanging above", "above", "upper part" and "upward" generally refer to a position located toward the inside of the can and therefore do not necessarily correspond to the concept of upward in the Earth's gravitational field. Similarly, the terms "lower", "below", "lower part" and "downward" generally refer to a position located toward the outside of the can and therefore do not necessarily correspond to the concept of downward in the Earth's gravitational field.

[0140] The wall 1 has a multi-layer structure, which includes, from the outside to the inside of the tank in the thickness direction E of the wall 1, a load-bearing structure 3, an auxiliary barrier 2, an outer sealing film 4, multiple spacer blocks 5, and an inner sealing film 6 intended to be in contact with liquefied gas (for example, liquid ammonia).

[0141] The load-bearing structure 3 may in particular be made of a self-supporting metal sheet, or in general of any type of rigid bulkhead having suitable mechanical properties, such as a concrete bulkhead or a bulkhead formed by the double hull of a ship.

[0142] The auxiliary barrier 2 is thermally insulating and fastened to the load-bearing structure 3 , the auxiliary barrier 2 for example comprising a plurality of thermal insulation panels (not shown) anchored to the load-bearing structure 3 .

[0143] The auxiliary barrier 2 may also comprise a secondary flexible membrane (not shown) made of a composite material joined to the insulation board.

[0144] The auxiliary barrier 2 may also comprise a second layer of thermal insulation board bonded to the secondary flexible membrane.

[0145] The outer sealing membrane 4 is made of metal, preferably stainless steel. The outer sealing membrane 4 includes parallel corrugations 14 and flat areas 15 defined between the corrugations 14. The corrugations 14 protrude from the flat areas 15 toward the inside of the can.

[0146] Similarly, the inner sealing membrane 6 is made of metal, preferably stainless steel. The inner sealing membrane 6 comprises parallel corrugations 16 and flat areas 17 defined between the corrugations 16. The corrugations 16 protrude from the flat areas 17 toward the inside of the can.

[0147] The corrugated portion 16 and the corrugated portion 14 , and the flat area 17 and the flat area 15 are respectively positioned opposite to each other.

[0148] The tank wall according to various embodiments is described in more detail below.

[0149] exist Figures 2 to 4 In, with Figure 1 Elements that are identical or similar to the elements in the drawings are denoted by the same reference numerals plus 100.

[0150] See below Figures 2 to 4 A first variation of a sealed tank wall 101 for storing liquefied gas (eg, ammonia) is described.

[0151] The tank wall 101 includes an outer sealing film 104, which includes a series of parallel small corrugations 114 and a series of large corrugations 118 perpendicular to the small corrugations 114. The large corrugations 118 and the small corrugations 114 protrude toward the inside of the tank. The height of the large corrugations 118 is greater than the height of the small corrugations 114.

[0152] Flat areas 115 are defined between the small corrugations 114 and between the large corrugations 118 .

[0153] Advantageously, the inner sealing membrane 106 is composed of a plurality of metal sheets which are welded together in a sealing manner.

[0154] Each metal sheet of the inner sealing film 106 has an edge, and a corner located at a junction between two edges of the inner sealing film 106 .

[0155] For example, Figure 2 and Figure 4 As shown, the spacer 105 is located on the flat area 115 of the outer sealing membrane 104. In this case, the thickness of the spacer 105 is between the height of the small corrugations 114 and the height of the large corrugations 118.

[0156] The spacer block 105 has an outer end 130 positioned against the flat area 115 , a flat inner surface 131 parallel to the outer end 130 and positioned against the flat area 117 of the inner sealing membrane 106 , and four lateral ends connecting the outer end 130 to the inner surface 131 .

[0157] The profile of the outer end portion 130 substantially corresponds to the profile of the flat region 115 and does not contact the roots of the small corrugations 114 and the large corrugations 118. The root of the corrugations can be defined as the region where the sealing membrane deviates toward the interior of the can. This deviated region is located between the corrugations and the flat region of the sealing membrane.

[0158] The four lateral ends extend between the outer end 130 and the inner surface 131 of the spacer block 105 and include a first lateral end 132 and a third lateral end 132 facing each other and extending parallel to the small corrugated portion 114 (i.e., extending in the longitudinal direction of the small corrugated portion 114), and a second lateral end 133 facing each other and extending parallel to the large corrugated portion 118 (i.e., extending in the longitudinal direction of the large corrugated portion 118). The lateral ends do not contact the corrugated portion.

[0159] The first and third lateral ends 132 are oriented toward the two small corrugations 114, respectively, without contacting the two small corrugations 114. The first and third lateral ends 132 extend toward the outside of the spacer block 105 so that the inner surface 131 is larger than the outer end 130 in a direction transverse to the small corrugations 114 (i.e., in a direction parallel to the large corrugations 118). This allows the two opposite end portions of the inner surface 131 to partially overhang the adjacent small corrugations 114 and support one root of the corrugations 116 of the inner sealing membrane 106. The first and third lateral ends 132 have a concave shape that matches the shape of a portion of the small corrugations 114, at a distance therefrom.

[0160] The spacer block 105 further includes a plurality of support ribs 134 forming a hollow cell 135. The hollow cell 135 is in the form of a plurality of aligned rectangular cells. The plurality of support ribs 134 enable the spacer block 105 to, among other things, support the inner sealing membrane 106 and withstand the hydrostatic pressure loads applied to the spacer block 105.

[0161] The spacer block 105 includes a temporary hole 121 through the thickness of the spacer block 105 in the middle of the spacer block 105 to enable the spacer block 105 to be fastened to the flat area 115 .

[0162] like Figure 4 As shown, a screw-nut system is used to fasten the spacer block 105 to the flat area 115. Other fastening systems may also be used.

[0163] To secure the spacer 105, a threaded rod 120 is welded to the flat area 115 of the outer sealing membrane 104, for example, by capacitor discharge welding, so that the threaded rod 120 protrudes upward (i.e., toward the inside of the tank). The spacer 105 is positioned on the flat area 115 by inserting the threaded rod 120 into a temporary hole 121. The spacer 105 is secured by a retaining surface that cooperates with a nut 122.

[0164] After fastening the spacer block 105 to the flat area 115, the temporary hole 121 is closed by the metal cover 123 so that the inner surface 131 is flat and can best support the inner sealing membrane 106. For example, the metal cover is made of aluminum or stainless steel.

[0165] The flat area 117 of the inner sealing membrane 106 rests on the flat inner surface 131 and is fastened to the spacer block 105. The fastening is performed, for example, by welding to a metal insert located on the inner surface 131. For example, the metal insert is a metal cover 123, which is fastened to a fastening portion 119 on the flat inner surface 131. It should be noted that the metal insert can also be located at another location on the inner surface 131.

[0166] Figure 5 A modified embodiment of the spacer block is shown. Figure 5 In, with Figures 2 to 4 Elements that are identical or similar to the elements in the drawings are denoted by the same reference numerals plus 100.

[0167] Spacer block 205 and Figures 2 to 4 The spacer block 205 differs from the spacer block 205 in that the first and third lateral ends 232 facing each other have a greater curvature. In addition, the through hole 221 has a different shape and includes a retaining surface 224 that cooperates with the threaded rod 220 and the nut 222 mounted on the threaded rod 220. The spacer block 205 includes fewer supporting ribs 234 and, therefore, fewer hollow cells 235.

[0168] The above-mentioned spacer blocks cover a single flat area of ​​the outer sealing membrane. However, the spacer blocks can have larger dimensions, in particular to cover a plurality of flat areas.

[0169] Figure 6 and Figure 7 Two variant embodiments of spacer blocks covering multiple flat areas are shown. Figure 6 and Figure 7 In, with Figures 2 to 4 Elements that are identical or similar to the elements in the drawings are denoted by the same reference numerals plus 200.

[0170] Figure 6 The spacer block 305 and Figures 2 to 4The spacer block 305 differs from the spacer block 305 in that the spacer block 305 is positioned on two adjacent flat areas 315 of the outer sealing membrane 304, separated by a small corrugation 314. Each flat area is bounded by two adjacent large corrugations 318 and two adjacent small corrugations 314. The outer end 330 of the spacer block 305 includes two flat portions, each positioned on a flat area 315. The outer end 330 of the spacer block 305 also includes a connecting portion 340 connecting the two flat portions. The connecting portion 340 extends above the small corrugation 314. In other words, the connecting portion 340 forms a tunnel through which the small corrugation 314 passes throughout the entire size of the spacer block 305.

[0171] Figure 7 The thickness of the spacer block 305 is greater than the height of the large corrugation 118. The outer end 330 of the spacer block 305 includes four flat portions, each of which is positioned on the flat area 315. The outer end 330 of the spacer block 305 also includes a connecting portion that connects the four portions of the outer end 330. The connecting portion extends above the small corrugation 314 or the large corrugation 318. In other words, the first connecting portion 340 of the spacer block 305 forms a tunnel through which the large corrugation 118 passes along the entire length of the spacer block 305. The second connecting portion 341 forms a tunnel through which the small corrugation 314 passes along the entire width of the spacer block 305. The inner surface 331 of the spacer block is larger than the outer end 330. Each of the four edges of the inner surface 331 partially overhangs the corrugation.

[0172] Figure 8 A modified embodiment of the spacer block is shown. Figure 8 In, with Figures 2 to 4 Elements that are the same or similar to the elements in FIG. 1 are denoted by the same reference numerals plus 300.

[0173] Figure 8 The two spacer blocks 405 and Figures 2 to 4 The difference between the spacer blocks in FIG. 4 is that two spacer blocks 405 are located at the corners of the can. The flat area 415 of the outer sealing membrane 404 is located between the corrugated portion 414 and the corners of the can.

[0174] The spacer blocks 405 are each positioned on the flat area 415 at the corner, and each include an inclined lateral end 432b opposite the lateral end 432. The inclined lateral ends 432b of the spacer blocks 405 are positioned to abut against each other. Figure 8 A 90° can corner with a 45° angled lateral end 432b is shown, but this arrangement can be adapted for positioning at another can corner, such as a 135° corner. Additionally, the two angled lateral ends 432b can have different angles of inclination from one another, as long as they form an angle that matches the can corner when joined together.

[0175] According to one embodiment, the tank wall can be derived from an existing sealed and insulated tank wall for storing LNG, in which the spacer blocks 5, 105, or 205 and the inner sealing membrane 6, 106, or 206 are already installed. Numerous structures of sealed and insulated tank walls for storing LNG exist in the prior art. According to one embodiment, the sealed and insulated tank wall for storing LNG complies with patent publications FR2739675 or WO2022200539. Therefore, further details regarding the auxiliary barrier 2 and the outer sealing membrane 4, 104, or 204 can be found in these patent publications.

[0176] Figure 9 and Figure 10 A modified embodiment of the spacer block is shown. Figure 9 and Figure 10 In, with Figures 2 to 4 Elements that are the same or similar to the elements in FIG. 1 are denoted by the same reference numerals plus 400.

[0177] Figure 9 The spacer block 505 and Figures 2 to 4 The spacer block in is different in that the spacer block 505 has a metal insert 550 forming at least a portion of the inner surface of the spacer block, to which the at least one flat portion of the inner sealing membrane is at least partially fastened.

[0178] Advantageously, this enables the inner sealing membrane 6, 106, 206, 306 to be welded to the spacer block 505. More precisely, the metal sheet of the inner sealing membrane 6, 106, 206, 306 has at least one edge or corner welded to the metal insert 550 of the spacer block 505. Advantageously, the metal insert 550 comprises at least one surface extending in a plane parallel to the inner surface 531 of the spacer block 505.

[0179] Advantageously, the metal insert 550 has a linear shape.

[0180] In another variation of the sixth embodiment, the spacer block 505 comprises two coplanar metal inserts 550. Advantageously, the two metal inserts 550 are oriented in the same direction.

[0181] In an embodiment not shown, the shape of the metal insert 550 matches one of the corners of the metal sheet of the inner sealing membrane 6, 106, 206, 306, thereby enabling welding in the joint area of ​​the plurality of metal sheets comprising the inner sealing membrane 6, 106, 206, 306. Advantageously, the spacer block 505 includes two metal inserts that form an angle that matches one of the corners of the metal sheet. Advantageously, the two metal inserts have shapes that complement each other to form the angle.

[0182] In a variation of this embodiment, the metal inserts 550 of the spacer block 505 form a cross. Advantageously, the spacer block 505 comprises three or four metal inserts 550.

[0183] In one embodiment, the spacer block comprises a single cross-shaped metal insert 550 .

[0184] In another variation of this embodiment, the metal inserts 550 of the spacer block 505 are formed in a “T” shape. The spacer block 505 includes two or three metal inserts 550 .

[0185] In one embodiment, the spacer block comprises a single T-shaped metal insert 550 .

[0186] Figure 9 and Figure 10 The spacer block 505 is shown to include a seat 551 that receives the metal insert 550. The seat 551 holds the metal insert 550 so that the metal insert 550 cannot move freely in the height direction of the spacer block 505 once in place.

[0187] The seat is able to prevent translational movement of the metal insert in the thickness direction E.

[0188] The spacer block 505 has an opening 552 on the inner surface 531 of the spacer block 505 along the transverse direction and / or the longitudinal direction. Advantageously, the opening 552 extends through the spacer block 505 along the entire length of the inner surface 531 along the transverse direction and / or the longitudinal direction. The opening 552 is bounded by at least two inner edges 553. The inner edges 553 match the shape of the metal insert 550. For example, if the shape of the metal insert 550 is linear, the opening 552 is bounded by two parallel inner edges 553.

[0189] The spacer block 505 further includes two flat protrusions 554 parallel to the two inner edges 553. The first flat protrusion 554 is positioned opposite the first inner edge 553, and the second flat protrusion 554 is positioned opposite the second inner edge 553, so that the space between the first flat protrusion 554 and the first inner edge 553 forms a first slot 555, and the space between the second flat protrusion 554 and the second inner edge 553 forms a second slot 555.

[0190] The seat 551 of the spacer block 505 includes two slots 555 .

[0191] In this embodiment, the two slots 555 extend in parallel and at least partially adjoin the opening 552 , in which case the two sides of the opening 552 are positioned opposite each other.

[0192] Therefore, when the metal insert 550 is assembled in the opening 552, the metal insert 550 is first inserted at the edge of the two slots 555 and opposite the two slots 555, and then slides into the spacer block 505 and in this case slides into the two slots 555 so that the metal insert 550 is fully inserted into the seat 551 of the spacer block 505.

[0193] Figure 10 Also shown is a possible shape of the metal insert 550. In this case, the metal insert 550 includes a flat central surface 560 extending in a first plane at a first height; two end portions 561 parallel to the flat central surface 560, extending in a second plane at a second height; and two joining portions 562 joining the flat central surface 560 to the two end portions 561. The two joining portions 562 may be flat or curved.

[0194] In other words, in this embodiment, the metal insert 550 has an omega-shaped cross-section.

[0195] The two parallel ends 561 of the metal insert 550 slide into the two slots 555 of the spacer block 505 so that the flat center surface 560 is in contact with the inner sealing membrane 6, 106, 206, 306. Advantageously, the difference between the first height and the second height enables the flat center surface 560 of the metal insert 550 to be flush with the inner surface 531 of the spacer block 505.

[0196] In other words, once assembled, the metal insert 550 forms a cover for the opening 552 .

[0197] Advantageously, the metal insert 550 can be arranged in a spacer block 505 that is already mounted and hooked to the outer sealing membrane 4 , 104 , 204 , 304 , 404 .

[0198] Advantageously, in the sixth embodiment, the spacer block 505 is made of metal, for example, aluminum.

[0199] Figure 11 and Figure 12 A modified embodiment of the spacer block is shown. Figure 11 and Figure 12 In, with Figures 2 to 4Elements that are identical or similar to the elements in the drawings are denoted by the same reference numerals plus 500.

[0200] Figure 11 and Figure 12 The spacer block 605 in Figures 2 to 4 The spacer block 605 differs from the spacer block 605 in that the spacer block 605 has a metal insert 650, which enables the inner sealing membrane 6, 106, 206, 306 to be welded to the spacer block 605. More specifically, the inner sealing membrane 6, 106, 206, 306 has at least one flat area 17, 117, 317, for example, located at one edge of the inner sealing membrane 6, 106, 206, 306, which is welded to the metal insert 650 of the spacer block 605. Advantageously, the spacer block 605 includes between one and four metal inserts 650.

[0201] Advantageously, the number of metal inserts 650 depends on the number of inner sealing films 6 , 106 , 206 , 306 in the joining area to be welded.

[0202] Figure 11 and Figure 12 The spacer block 605 is shown to include at least one seat 651 that accommodates the metal insert 650. The seat 651 holds the metal insert 650 so that the metal insert 650 cannot move freely in the height direction of the spacer block 605 once in place.

[0203] The spacer block 605 has an opening 652 in the transverse and longitudinal directions on the inner surface 631 of the spacer block 605. Advantageously, the opening 652 passes through the spacer block 605 in the transverse and longitudinal directions over the entire length of the inner surface 631. In this case, the opening 652 is defined by eight inner edges 653. In this embodiment, the opening 652 is substantially cross-shaped.

[0204] Figure 11 and Figure 12 Also shown is a possible shape of a metal insert 650. The metal insert 650 includes a flat central surface 660 extending in a first plane at a first height, two end portions 661 parallel to the flat central surface 660 and extending in a second plane at a second height, and two joining portions 662 joining the flat central surface 660 to the two end portions 561. The two joining portions 662 may be flat or curved.

[0205] In other words, in this embodiment, the metal insert 650 has an omega-shaped cross-section.

[0206] Advantageously, the difference between the first height and the second height enables the flat center surface 660 of the metal insert 650 to be flush with the inner surface 631 of the spacer block 605 .

[0207] In other words, once assembled, the metal insert 650 forms a cover for the opening 652 .

[0208] In this embodiment, the metal insert 650 is toothed, more specifically, each of the two ends 661 of the metal insert 650 has at least one notch 663. Advantageously, the end 661 has a plurality of notches 663, for example having a similar repeating shape. More advantageously, the notches 663 are rectangular.

[0209] In this embodiment, the inner edge 653 of the spacer block 605 is also toothed. More specifically, the inner edge 653 has a shape that is complementary to the end 661 of the metal insert 650, so that if the spacer block 605 is already mounted and hooked to the outer sealing membrane 4, 104, 204, 304, 404, the metal insert 650 can be inserted from the thickness direction E.

[0210] Advantageously, once the metal insert 650 has been inserted into the spacer block 605 , a translational movement towards the center of the spacer block 605 prevents the metal insert 650 from moving in the height direction.

[0211] In one embodiment (not shown), the filler is disposed in the seat 651 of the spacer block 605 that does not include the metal insert 650 .

[0212] Advantageously, in the seventh embodiment, the spacer block 605 is made of a thermoplastic material.

[0213] Advantageously, the metal inserts 550 , 650 of the sixth and seventh embodiments have protrusions that enable the metal inserts 550 , 650 to be inserted and that enable the metal inserts 550 , 650 to be moved in translation in the openings 552 , 652 .

[0214] Advantageously, the spacer block 605 of the seventh embodiment has a metal cover 623 .

[0215] This metal cover 623 is for example arranged in the centre of the inner surface 631 of the spacer block 605 and prevents translational movement of the metal insert 650. The metal cover 623 may also serve to fasten the spacer block 650 to the outer sealing membrane 4,104,204,304,404.

[0216] Advantageously, the spacer block 505 of the sixth embodiment comprises a metal cover as described above.

[0217] Advantageously, the spacer blocks 505 , 605 of the sixth and seventh embodiments have an inner recess for each metal insert 550 , 650 to prevent translational movement of the metal inserts 550 , 650 .

[0218] Advantageously, the spacer blocks 505 , 605 of the sixth and seventh embodiments have fastening means for each metal insert 550 , 650 to fasten the metal insert 550 , 650 inside the spacer blocks 505 , 605 .

[0219] Reference Figure 13 , a cross-sectional view of a vessel 70 shows a sealed and insulated tank 71 having a generally prismatic shape installed in the vessel's double hull 72. The wall of the tank 71 has a primary sealing membrane designed to be in contact with the liquefied gas contained in the tank, a secondary sealing membrane arranged between the primary sealing membrane and the vessel's double hull 72, and two thermal insulation barriers arranged between the primary sealing membrane and the secondary sealing membrane and between the secondary sealing membrane and the double hull 72, respectively.

[0220] In a known manner, a loading / unloading pipe 73 arranged on the upper deck of the vessel can be connected to a marine or port terminal using appropriate connectors to allow the liquefied gas cargo to be transferred into or out of the tank 71 .

[0221] Figure 13 Also shown is an example marine terminal including a loading / unloading station 75, an underwater pipeline 76, and an onshore facility 77. The loading / unloading station 75 is a fixed offshore facility comprising a movable arm 74 and a mast 78 supporting the movable arm 74. The movable arm 74 carries a bundle of insulated flexible hoses 79 that can be connected to the loading / unloading pipeline 73. The orientable movable arm 74 is adaptable to vessels of all sizes. Connecting pipelines (not shown) extend inside the mast 78. The loading / unloading station 75 enables vessels 70 to be loaded from or unloaded to an onshore facility 77. The facility has a liquefied gas storage tank 80 and a connecting pipeline 81 connected to the loading / unloading station 75 via the underwater pipeline 76. The underwater pipeline 76 enables the transfer of liquefied gas between the loading / unloading station 75 and the onshore facility 77 over a relatively long distance (e.g., 5 km), which enables the vessel 70 to be moved a considerable distance from shore during loading and unloading operations.

[0222] In order to generate the pressure required to transport the liquefied gas, a pump carried on board the vessel 70 and / or a pump installed at the onshore facility 77 and / or a pump installed at the loading / unloading station 75 can be used, or the pressure in the internal space of the tank caused by the evaporation of the liquefied gas stored in the tank can be allowed to increase.

[0223] Although the present invention has been described in conjunction with a number of specific embodiments, it is obvious that the present invention is by no means limited thereto, and the present invention includes all technical equivalents of the described devices and combinations thereof, wherein all technical equivalents of these devices and combinations thereof fall within the scope of the present invention.

[0224] Use of the verb "comprise" or "include" (including its conjugations) does not exclude the presence of elements or steps other than those stated in a claim.

[0225] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Claims

1. A sealed tank for storing liquefied gas, comprising a tank wall (1, 101, 201, 301, 401) intended to be installed in a load-bearing structure (3), the tank wall comprising, in a thickness direction (E) of the tank wall: - a metallic outer sealing membrane (4, 104, 204, 304, 404) comprising a first series of parallel corrugations (14, 114, 214, 314, 414) and a flat area (15, 115, 215, 315, 415); a spacer block (5, 105, 205, 305, 405, 505, 605) arranged on at least one of the flat areas (15, 115, 215, 315, 415) of the outer sealing membrane and fastened to the outer sealing membrane, The spacer block has an outer end (130, 230, 330, 430), a flat inner surface (131, 231, 331, 431, 531, 631) parallel to the outer end, and lateral ends (132, 133, 232, 332, 432, 532, 533, 632, 633) connecting the outer end to the inner surface, the outer end being positioned against at least one of the flat areas, the lateral ends including a first lateral end (132, 232, 332, 432, 532, 632) extending parallel to and oriented toward a first corrugation of the first series of corrugations (14, 114, 214, 314, 414), the inner surface including a first end portion partially overhanging the first corrugation; as well as - a metallic inner sealing membrane (6, 106, 206, 306) intended to be in contact with the liquefied gas, wherein the inner sealing membrane is separated from the outer sealing membrane by the spacer block, the inner sealing membrane comprising at least one flat portion (17, 117, 317) fastened to the inner surface of the spacer block.

2. The sealed can according to claim 1, wherein: The first lateral end portion has a concave shape to overhang the first corrugated portion.

3. The sealed can according to claim 1 or 2, wherein: The first lateral end portion does not contact the first corrugated portion.

4. The sealed can according to any one of claims 1 to 3, wherein At least one of the flat areas comprises a first flat area, and wherein the thickness of the spacer block is greater than the height of the first series of corrugations in the thickness direction of the tank wall, and wherein the outer end of the spacer block is arranged on at least one second flat area (15, 115, 215, 315, 415) of the outer sealing membrane, the spacer block extending above at least one other corrugation (14, 114, 214, 314, 414) of the first series of corrugations located between the first flat area and the second flat area.

5. The sealed can according to any one of claims 1 to 4, wherein The outer sealing membrane includes a second series of corrugations (118, 218, 318) perpendicular to the first series of corrugations, wherein the lateral end portion includes a second lateral end portion (133, 333, 533, 633), the second lateral end portion extending parallel to the second series of corrugations and oriented toward the first corrugation portion in the second series of corrugations, and the inner surface includes a second end portion partially suspended above the first corrugation portion in the second series of corrugations.

6. The sealed can according to claim 5, wherein: In the thickness direction (E) of the tank wall, the height of the first series of corrugations is smaller than the height of the second series of corrugations, wherein the thickness of the spacer block is between the height of the second series of corrugations and the height of the first series of corrugations.

7. The sealed can according to claim 5, wherein: The thickness of the spacer block is greater than the height of the second series of corrugations in the thickness direction of the tank wall, and wherein the outer end of the spacer block is arranged on at least one other flat area (15, 115, 215, 315, 415) of the outer sealing membrane, and the spacer block extends above one other corrugation (118, 218, 318) of the second series of corrugations located between the first flat area and the other flat area.

8. The sealed can according to any one of claims 1 to 7, wherein: The lateral end portion includes a third lateral end portion (132, 232, 332, 432, 532, 632) positioned opposite the first lateral end portion, the third lateral end portion extending parallel to the first series of corrugations, the inner surface includes a third end portion partially overhanging the second corrugation portion in the first series of corrugations, and in a direction transverse to the first series of corrugations, the size of the inner surface (131, 231) is larger than the size of the outer end portion (130, 230).

9. The sealed can according to any one of claims 1 to 8, wherein The spacer block includes supporting ribs (134, 234) and hollow units (135, 235), wherein the supporting ribs are located below the inner surface and between the lateral ends, and the hollow units are located between the supporting ribs.

10. The sealed can according to claim 9, wherein: The outer end portion of the spacer block is formed by the edge of the lateral end portion and / or the end edge of the supporting rib, and the hollow unit is open at the outer end portion of the spacer block.

11. The sealed can according to claim 9 or 10, wherein: The first lateral end portion is formed by a lateral edge of the supporting rib.

12. The sealed can according to any one of claims 1 to 11, wherein The sealing can further includes a fastener (120, 220) fastened to the flat area of ​​the outer sealing film and protruding toward the inner sealing film, and the spacer block is fastened to the fastener.

13. The sealed can according to any one of claims 1 to 12, wherein: The spacer block comprises at least one metal insert (550, 650) forming at least a portion of the inner surface of the spacer block, the at least one flat portion of the inner sealing membrane being at least partially fastened to the metal insert.

14. The sealed can according to claim 13, wherein: The spacer block comprises a seat (551, 651) for receiving the metal insert, the seat being capable of preventing translational movement of the metal insert in the thickness direction (E).

15. The sealed can according to any one of claims 1 to 14, wherein The inner sealing film comprises a first series of corrugations (16, 116, 216, 316) parallel to the first series of corrugations of the outer sealing film, and a flat area (17, 117), at least one of the first series of corrugations of the inner sealing film being opposite to the first corrugation of the first series of corrugations of the outer sealing film in the thickness direction of the tank wall.

16. A method for modifying a sealed tank originally used to store a first liquefied gas, the method comprising: A spacer block (5, 105, 205, 305, 405, 505, 605) is fastened to at least one flat area (15, 115, 215, 315, 415) of an outer sealing membrane (4, 104, 204, 304, 404), wherein the outer sealing membrane is a main membrane belonging to a sealed tank wall (1, 101, 201, 301, 401) for storing the first liquefied gas, the outer sealing membrane being made of metal and comprising a first series of parallel corrugated portions (14, 114, 214, 314, 414), the spacer block having an outer end portion (130, 230, 330, 430), a flat inner surface (131, 231, 331, 431, 531, 631) parallel to the outer end portion, and a flat inner surface (131, 231, 331, 431, 531, 631) connecting the outer end portion to the inner surface. lateral ends (132, 133, 232, 332, 432, 532, 533, 632, 633) of the surface, the outer end being positioned to abut against the at least one flat area, the lateral ends comprising a first lateral end (132, 232, 332, 432, 532, 632), the first lateral end extending parallel to the first series of corrugations and oriented toward a first corrugation in the first series of corrugations, the inner surface comprising a first end portion partially overhanging the first corrugation; and securing at least one flat area (17, 117, 317) of a metallic inner sealing membrane (6, 106, 206, 306) to the inner surface of the spacer block such that the inner sealing membrane is separated from the outer sealing membrane by the spacer block.

17. Onshore installation comprising a load-bearing structure and a tank according to any one of claims 1 to 15, the tank being arranged in the load-bearing structure.

18. A ship (70) for transporting liquefied gas, the ship comprising a double hull (72) and a tank (71) according to any one of claims 1 to 15, the tank being arranged inside the double hull.

19. A transfer system for liquefied gas, the system comprising a vessel (70) according to claim 18 and insulated piping (73, 79, 76, 81) arranged to connect the tanks (71) on the vessel to an onshore or floating storage facility (77).

20. A method for loading or unloading a vessel (70) according to claim 18, wherein: The liquefied gas is conducted through insulated pipes (73, 79, 76, 81) to or from an onshore or floating storage facility (77) to or from the tank (71) on the vessel (70).

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