Watertight and thermally insulated tank with anti-convective filling plate

Abstract

A sealed, thermally insulated fluid storage vessel, wherein a vessel wall comprises a secondary thermal insulation barrier, a secondary sealing membrane, a primary thermal insulation barrier, and a primary sealing membrane supported by the primary thermal insulation barrier (5), wherein the primary insulating elements (6) have parallelepiped insulating panels arranged to provide spaces (8) between them, the primary thermal insulation barrier (5) further comprises an anti-convective filler plate (37) arranged in the space between a first parallelepiped insulating panel (6) and a second parallelepiped insulating panel,The anti-convective filler plate (37) is made of thin continuous material and has a plurality of elongated wall elements (42) that extend substantially across the entire width of the space to define cells that extend substantially perpendicular to the thickness direction.

Description

technical field

[0001] The invention relates to the field of sealed and thermally insulating membrane tanks for the storage and / or transport of fluid, such as a cryogenic fluid.

[0002] Leak-proof, thermally insulated membrane tanks are used, in particular, for storing liquefied natural gas (LNG), which is stored at atmospheric pressure at approximately -162°C. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank can be used for transporting liquefied natural gas or for receiving liquefied natural gas to serve as fuel for the propulsion of the floating structure. Technological background

[0003] In the prior art, leak-proof and thermally insulated tanks for the storage of liquefied natural gas are known, integrated into a load-bearing structure, such as the double hull of a ship intended for the transport of liquefied natural gas. Generally, such tanks comprise a multi-layered structure having successively, in the thickness direction, from the outside to the inside of the tank, a secondary thermal insulation barrier attached to the load-bearing structure, a secondary sealing membrane resting against the secondary thermal insulation barrier, a primary thermal insulation barrier resting against the secondary sealing membrane, and a primary sealing membrane resting against the primary thermal insulation barrier and intended to be in contact with the liquefied natural gas contained in the tank.

[0004] Document WO2016 / 046487 describes a secondary thermal insulation barrier and a primary thermal insulation barrier formed from juxtaposed insulating panels. In this document, the secondary sealing membrane consists of a plurality of metal sheets with corrugations projecting outwards from the tank, thus allowing the secondary sealing membrane to deform under the thermal and mechanical stresses generated by the fluid stored in the tank. An inner face of the insulating panels of the secondary thermal insulation barrier has grooves that receive the corrugations of the corrugated metal sheets of the secondary sealing membrane. These corrugations and grooves form a network of channels extending along the walls of the tank.

[0005] Document WO2015 / 132498 describes a sealed and thermally insulated tank comprising a deflection element allowing gas to flow at a corner.

[0006] The document WO2014 / 128414 describes a sealed and thermally insulating wall for a cryogenic fluid storage tank, the wall comprising insulating junction elements arranged in a constrained position between insulating sectors, the insulating junction elements being able to expand during a thermal contraction of the insulating sectors.

[0007] The document JP H04194498 describes an insulation device intended to be placed between insulating elements. Summary

[0008] One idea underlying the invention is to provide a sealed and thermally insulating tank with a corrugated sealing membrane in which convection phenomena are reduced. In particular, another idea underlying the invention is to provide a sealed and thermally insulating tank that limits the presence of continuous circulation channels in the thermal insulation barriers in order to limit natural convection phenomena within said thermal insulation barriers.

[0009] According to one embodiment, the invention provides a sealed and thermally insulated tank for storing a fluid, in which a tank wall comprises, successively in a thickness direction, a secondary thermal insulation barrier comprising a plurality of juxtaposed secondary insulating elements, the secondary insulating elements being retained against a load-bearing wall, for example by secondary retaining devices, a secondary sealing membrane supported by the secondary insulating elements of the secondary thermal insulation barrier, a primary thermal insulation barrier comprising a plurality of juxtaposed primary insulating elements, the primary insulating elements being retained against the secondary sealing membrane, for example by primary retaining devices, and a primary sealing membrane supported by the primary thermal insulation barrier and intended to be in contact with the cryogenic fluid contained in the tank.according to claim 1.,

[0010] The primary insulating elements comprise parallelepiped insulating panels arranged to leave gaps between them, the primary thermal insulation barrier further comprising an anti-convective filling plate arranged in the gap between a first parallelepiped insulating panel and a second parallelepiped insulating panel, the second parallelepiped insulating panel being adjacent to the first parallelepiped insulating panel, the anti-convective filling plate being made of a continuous thin material and having a plurality of elongated wall elements extending substantially across the entire width of the gap to delimit cells extending substantially perpendicular to the thickness direction.

[0011] Thanks to such a filler plate, it is possible to limit convection currents in the gaps between parallelepiped insulating panels, particularly along the thickness of the tank wall. Preferably, the filler plate is made of a relatively flexible material, such as paper, cardboard, or plastic sheeting, especially polyetherimide or polyamide imide, so that the cells can easily compress and thus adapt to the width of the gap.

[0012] The length of such a filler plate can be greater, less than, or substantially equal to the length of the edges of the parallelepiped insulating panels between which the gap is formed.

[0013] Such a filler plate may in particular be interrupted or cut at the location of the primary retaining devices, at least when the primary retaining devices are also arranged in the gaps.

[0014] According to one embodiment, the elongated wall elements are formed from successive portions of a sheet of corrugated material having alternating parallel undulations extending substantially perpendicularly to the thickness direction.

[0015] In one embodiment, the infill panel has a sandwich structure comprising two parallel continuous sheets separated by elongated wall elements, these two parallel continuous sheets being arranged against two lateral faces of the first and second parallelepiped insulating panels defining the gap. In such a sandwich structure, the width of the cells is in fact equal to the width of the gap minus the thickness of the two parallel continuous sheets.

[0016] In one embodiment, the elongated wall elements are formed of cylindrical elements extending substantially perpendicularly to the thickness direction and fixed between two parallel continuous sheets. The cross-sectional shape of such cylindrical elements can be arbitrary, for example hexagonal, circular, or other.

[0017] According to one embodiment, at least one of the two continuous parallel sheets spaced by said elongated wall elements comprises a portion of upper edge folded and fixed to the inner face of at least one of the two parallelepiped insulating panels between which the gap is formed.

[0018] According to one embodiment, the inner face of the first and / or second parallelepiped insulating panel has a counterbore along the gap to accommodate said portion of the upper edge of the continuous sheet.

[0019] Thanks to these characteristics, it is possible to house and fix the upper edge portion of the continuous sheet without affecting the flatness of the inner face of the parallelepiped insulating panel that supports the waterproofing membrane.

[0020] According to one embodiment, the gap between the first parallelepiped insulating panel and the second parallelepiped insulating panel has a width of less than 10 mm.

[0021] Such a tank can be part of an onshore storage facility, for example to store LNG, or be installed in a floating, coastal or deep-water structure, including an LNG carrier, LNG tanker, a floating storage and regasification unit (FSRU), a floating production and remote storage unit (FPSO), and others.

[0022] According to one embodiment, a ship for the transport of a cold liquid product comprises a double hull and the aforementioned tank arranged in the double hull.

[0023] According to one embodiment, the invention also provides a method for loading or unloading such a vessel, in which a fluid is conveyed through insulated pipes from or to a floating or land-based storage facility to or from the vessel's tank.

[0024] According to one embodiment, the invention also provides a transfer system for a fluid, the system comprising the aforementioned vessel, insulated pipes arranged to connect the tank installed in the hull of the vessel to a floating or land-based storage facility, and a pump to drive a fluid through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank. Brief description of the figures

[0025] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation, with reference to the accompanying drawings. There figure 1 is a cutaway perspective view of the wall of a sealed and thermally insulating tank for storing a fluid; There figure 2 represents a cross-sectional view of a sealed and thermally insulating tank wall not part of the invention but useful for understanding the invention; There figure 3 is a partial schematic perspective view of a sealed and thermally insulating tank not part of the invention but useful for understanding the invention in which the primary sealed membrane is not illustrated; There figure 4is a partial cross-sectional view of a gap between two insulating panels of the primary thermally insulating barrier of the figure 2 , not forming part of the invention but useful for understanding the invention; There figure 5 is a partial cross-sectional view of a gap between two insulating panels of the primary thermally insulating barrier according to one embodiment variant of the figure 4 , not forming part of the invention but useful for understanding the invention; THE figures 6 to 10 are partial cross-sectional views of a gap between two insulating panels of the primary thermally insulating barrier according to embodiments; There figure 11 is a schematic cutaway representation of a tank on an LNG carrier and a loading / unloading terminal for that tank; There figure 12is a schematic representation of the internal plates of three adjacent primary insulating panels on which rests an L-shaped anti-convection plate, not part of the invention but useful for understanding the invention. Detailed description of implementation methods

[0026] By convention, the terms "external" and "internal" are used to define the relative position of one element with respect to another, by reference to the inside and outside of the tank.

[0027] On the figure 1 , we have represented the multilayer structure of a sealed and thermally insulating tank wall for storing a fluid.

[0028] Such a tank wall comprises, from the outside to the inside of the tank, a secondary thermal insulation barrier 1 comprising secondary insulation panels 2 juxtaposed and anchored to a load-bearing structure 3 by secondary retaining devices (not shown), for example studs welded to the load-bearing structure 3, a secondary sealing membrane 4 carried by the secondary insulation panels 2 of the secondary thermal insulation barrier 1, a primary thermal insulation barrier 5 comprising primary insulation panels 6 juxtaposed and anchored to the secondary insulation panels 2 of the secondary thermal insulation barrier 1 by primary retaining devices 19 and a primary sealing membrane 7, carried by the primary insulation panels 6 of the primary thermal insulation barrier 5 and intended to be in contact with the cryogenic fluid contained in the tank.

[0029] The load-bearing structure 3 may be, in particular, a self-supporting metal plate or, more generally, any type of rigid bulkhead with suitable mechanical properties. The load-bearing structure 3 may, in particular, be formed by the hull or double hull of a ship. The load-bearing structure 3 comprises a plurality of walls defining the overall shape of the tank, usually a polyhedral shape.

[0030] The secondary insulating panels 2 are essentially rectangular in shape. Each secondary insulating panel 2 comprises an insulating layer 9, for example, an insulating polymer foam 9, sandwiched between an internal rigid plate 10 and an external rigid plate 11. The rigid plates, internal 10 and external 11, are, for example, plywood panels bonded to the insulating polymer foam layer 9. The insulating polymer foam may, in particular, be a polyurethane-based foam. The polymer foam is advantageously reinforced with glass fibers, which help to reduce its thermal shrinkage.

[0031] The secondary insulating panels 2 are placed side by side in parallel rows and separated from each other by gaps 12 ensuring a functional assembly clearance. The gaps 12 are filled with a thermal insulation gasket 13, shown in the Figures 1 And 2such as glass wool, rock wool, or flexible open-cell synthetic foam, for example. The thermal insulation lining 13 is advantageously made of a porous material to allow gas circulation in the gaps 12 between the secondary insulating panels 2, for example, the circulation of an inert gas, such as nitrogen, within the secondary thermal insulation barrier 1 to maintain it under an inert atmosphere and thus prevent combustible gas from reaching an explosive concentration range and / or to place the secondary thermal insulation barrier 1 under negative pressure to increase its insulating capacity. This gas circulation is also important for facilitating the detection of any combustible gas leaks. The gaps 12, for example, have a width of approximately 30 mm.

[0032] The inner plate 10 has two sets of grooves 14, 15, perpendicular to each other, forming a network of grooves. Each set of grooves 14, 15 is parallel to two opposite sides of the secondary insulating panels 2. The grooves 14, 15 are designed to receive corrugations 25, 26, projecting outwards from the tank, formed on metal sheets 24 of the secondary sealing membrane 4. In the embodiment shown in the figure 1 , the inner plate 10 has three grooves 14 extending along the longitudinal direction of the secondary insulating panel 2 and nine grooves 15 extending along the transverse direction of the secondary insulating panel 2.

[0033] Furthermore, the inner plate 10 is equipped with metal plates 17, 18 for anchoring the edge of the corrugated metal sheets 24 of the secondary sealing membrane 4 to the secondary insulation panels 2. The metal plates 17, 18 extend in two perpendicular directions which are each parallel to two opposite sides of the secondary insulation panels 2. The metal plates 17, 18 are fixed to the inner plate 10 of the secondary insulation panel 2, by screws, rivets or staples, for example. The metal plates 17, 18 are placed in recesses formed in the inner plate 10 such that the inner surface of the metal plates 17, 18 is flush with the inner surface of the inner plate 10. The inner plate 10 has an inner surface that is substantially flat, except for any special areas such as grooves 14, 15 or counterbores for housing the metal plates 17, 18.

[0034] The inner plate 10 is also equipped with threaded studs 19 protruding into the interior of the tank, intended to secure the primary thermal insulation barrier 5 to the secondary insulation panels 2 of the secondary thermal insulation barrier 1. The metal studs 19 pass through holes provided in the metal plates 17.

[0035] The secondary sealing membrane 4 comprises a plurality of corrugated metal sheets 24, each having a substantially rectangular shape. The corrugated metal sheets 24 are arranged in a staggered manner relative to the secondary insulating panels 2 of the secondary thermal insulation barrier 1 such that each of said corrugated metal sheets 24 extends simultaneously over four adjacent secondary insulating panels 2.

[0036] Each corrugated metal sheet 24 has a first series of parallel corrugations 25 extending in one direction and a second series of parallel corrugations 26 extending in a second direction. The directions of the corrugation series 25 and 26 are perpendicular. Each series of corrugations 25 and 26 is parallel to two opposite edges of the corrugated metal sheet 24. The corrugations 25 and 26 project outwards from the tank, i.e., towards the supporting structure 3. The corrugated metal sheet 24 has a plurality of flat surfaces between the corrugations 25 and 26. At each intersection of two corrugations 25 and 26, the metal sheet 24 has a node zone.

[0037] The corrugations 25, 26 of the corrugated metal sheets 24 are housed in the grooves 14, 15 formed in the inner plate 10 of the secondary insulating panels 2. Adjacent corrugated metal sheets 24 are welded together with an overlap. The corrugated metal sheets 24 are anchored to the metal plates 17, 18 by tack welds.

[0038] Corrugated metal sheets 24 are, for example, made of Invar®: that is, an iron and nickel alloy whose coefficient of expansion is typically between 1.2 x 10⁻⁶ and 2 x 10⁻⁶ K⁻¹, or of a high-manganese iron alloy whose coefficient of expansion is typically around 7 x 10⁻⁶ K⁻¹. Alternatively, corrugated metal sheets 24 can also be made of stainless steel or aluminum.

[0039] The primary thermal insulation barrier 5 comprises a plurality of primary insulation panels 6, substantially rectangular in shape. The primary insulation panels 6 are offset from the secondary insulation panels 2 of the secondary thermal insulation barrier 1 such that each primary insulation panel 6 spans four secondary insulation panels 2 of the secondary thermal insulation barrier 1. Adjacent primary insulation panels 6 are spaced apart by a gap 8, ensuring sufficient clearance for the installation of said primary insulation panels 6. However, this gap 8 is smaller than the gap 12 between two adjacent secondary insulation panels 2 of the secondary thermal insulation barrier 1. Thus, the gap 8 separating two primary insulation panels 6 of the primary thermal insulation barrier 5 is approximately 4 mm plus or minus 3 mm.

[0040] The primary insulating panels 6 have a structure similar to the secondary insulating panels 2 of the secondary thermal insulation barrier 1, namely a sandwich structure consisting of an insulating lining layer, such as a layer of insulating polymer foam 29, sandwiched between two rigid plates, internal 30 and external 31, for example, made of plywood. The internal plate 30 of a primary insulating panel 6 is equipped with metal plates 32, 33 for anchoring corrugated metal sheets 39 of the primary sealing membrane 7 in a manner similar to the metal plates 17, 18 for anchoring the corrugated metal sheets 24 of the secondary sealing membrane 4. Likewise, the internal plate 30 and external plate 31 are preferably flat, excluding any singular areas.

[0041] The primary waterproofing membrane 7 is obtained by assembling a plurality of corrugated metal sheets 39 similar to the corrugated metal sheets 24 of the secondary waterproofing membrane 4. Each corrugated metal sheet 39 has two sets of corrugations 40 perpendicular to each other. The corrugations 40 of each of said sets of corrugations 40 are parallel to a respective side of the corresponding corrugated metal sheet 39. In the embodiment illustrated in the figure 1 The corrugations 40 protrude towards the inside of the tank. The corrugated metal sheets 39 are, for example, made of stainless steel or aluminum.

[0042] Further details and other embodiments, in particular on the secondary thermal insulation barriers 1 and primary 5, the anchoring devices of the thermally insulating barriers 1 and 5 and the sealing membranes 4 and 7, can be found in document WO2016 / 046487, document WO2013004943 or document WO2014057221.

[0043] In such a tank, the undulations 25, 26 of the secondary sealing membrane 4 constitute a network of circulation channels. Such channels develop continuously between the secondary sealing membrane 4 and the primary thermal insulation barrier 5 throughout the tank wall. These channels thus promote convection currents, particularly on tank walls with a significant vertical component, such as transverse tank walls. This network of continuous channels can generate thermosiphon phenomena in the primary thermal insulation barrier 5. One aspect of the invention stems from the idea of ​​preventing these convection currents in the tank walls. figure 2 represents a cross-sectional view of a sealed and thermally insulating tank wall, useful for understanding the invention. Elements identical to or performing the same function as those described above have the same reference numerals.

[0044] The corrugations 25, 26 of the secondary sealing membrane 4 and the corrugations 40 of the primary sealing membrane 7 are inward-curving corrugations, meaning they protrude towards the interior of the tank. Thus, the grooves 14, 15 housing the corrugations 25, 26 of the secondary sealing membrane 4 are formed in the outer plates 30 of the primary insulating panels 6. Consequently, the filling block 16 and the filling bar 22 are arranged between the corrugated metal sheets 24 and the inner plates 10 of the secondary insulating panels 2. Furthermore, the third filling block 23 is housed in the grooves 14, 15 formed in the outer plates 30 of the primary insulating panels 6, between said primary insulating panels 6 and the corrugations 25, 26 of the secondary sealing membrane 4.

[0045] Furthermore, as illustrated on the figure 2The filling block 16 and the filling bar 22 can also be positioned under the corrugations 40 of the primary waterproofing membrane 7, between said corrugations 40 and the inner plate 31 of said primary insulating panels 6. An insulating gasket 51 can also be positioned in wells made at the corners of the primary insulating panels 6 to accommodate the anchoring devices 19. As with the previous embodiments, it is possible to install a filling block in all or only some of the nodes and / or corrugations of the secondary 4 and / or primary 7 waterproofing membrane and / or the grooves accommodating said corrugations.

[0046] There figure 3This is a partial perspective view of the sealed and thermally insulated tank in which the primary waterproof membrane is not shown. Components identical to or performing the same function as those described above have the same reference figures.

[0047] On this figure 3 , the space 8 between two primary insulating panels 6 is illustrated by discontinuous lines 28. In a manner analogous to the undulations 25, 26 and the grooves 14, 15, the spaces 8 between the primary insulating panels 6 therefore constitute a mesh forming circulation channels allowing by convection the circulation of cold towards the secondary sealing membrane 4 and the formation of thermosiphons which are detrimental to the insulation of the tank wall, in particular because the primary sealing membrane 7 in contact with the LNG contained in the tank is carried by the said primary insulating panels 6.

[0048] There figure 3provides for the installation of anti-convection cover plates 34 arranged between the primary insulation panels 6 adjacent to the spaces 8 between said adjacent primary insulation panels. Such anti-convection cover plates 34 can be made of many materials. Preferably, these anti-convection cover plates are made of continuous, non-porous or slightly porous materials. Thus, the anti-convection cover plates 34 are, for example, paper films, cardboard, or synthetic, plastic, or other films. Such anti-convection cover plates can be arranged at all the spaces 8, as illustrated in the figure 3 , or only some of said spaces 8.

[0049] In relation to the figure 4The anti-convection cover plate 34 extends along the primary insulating panels 6 at the level of the space 8 between said primary insulating panels 6. An internal edge of the inner plate 31 of said primary insulating panels 6 has a counterbore 35 in which is housed a corresponding edge 36 of the anti-convection cover plate 34 so that the anti-convection cover plate 34 is flush with the inner face of said inner plate 31. Thus, the anti-convection cover plate 34 covers the space 8 and separates the space 8 from the primary sealing membrane 7, preventing the formation of channels having different temperatures likely to generate a thermosiphon phenomenon in the mesh formed by the spaces 8 of a tank wall.

[0050] Preferably, the anti-convection plate is made of a waterproof material with a thickness between 0.2mm and 2mm. This waterproof material is, for example, a plastic material (PEI, PVC, ...), cardboard, thick laminated paper, a fiberboard or other.

[0051] The anti-convection cover plate 34 has a width chosen so that the anti-convection plate rests in the grooves 35 on a minimum bearing surface, for example, at least 10 mm, regardless of the contraction state of the inner plates 31 and said anti-convection cover plate 34. In other words, the anti-convection cover plate 34 is dimensioned so that its edges 36 are housed in the grooves 35 even when the tank is full of LNG. To achieve this, one of the edges 36 of the anti-convection plate may partially protrude from the groove 35 to overlap the inner plate 31 outside the groove 35, thus ensuring that said edge 36 remains housed in the groove in its contracted state. The edges 36 of the anti-convection cover plate 34 are stapled or glued to one of the two primary insulation panels 6 in the groove 35.

[0052] As illustrated on the figure 3The primary thermal insulation barrier 5 comprises a plurality of closure plates 38 to complete the bearing surface of the primary waterproofing membrane 7 at the level of recesses that house the anchoring elements 19 of the primary thermal insulation barrier 5. Since these recesses are located in line with the spaces 8 between the primary insulation panels 6, the anti-convection cover plates 34 can be interrupted at the level of said closure plates 38. Preferably, in this case, the anti-convection cover plates 34 are abutting said closure plates 38 so as to limit the presence of gaps between the primary waterproofing membrane 7 and the spaces 8. Preferably, the anti-convection cover plates 34 and the closure plates 38 are flush with the inner plates 31 of the primary insulation panels 6 in order to form a continuous flat surface for the primary waterproofing membrane 7.

[0053] In an alternative embodiment not shown, the anti-convection plates 34 at least partially cover the closing plates 38. The ends of the anti-convection cover plates 34 are for example housed in counterbores (not shown) provided in the closing plates 38 so that the closing plates 38 and the anti-convection plates 34 are flush with the internal plates 31 of the primary insulating panels 6.

[0054] In another variant, the anti-convection plates 34 are continuous and completely cover the closure plates 38. Preferably, the anti-convection cover plates 34 are flush with the internal plates 31 of the primary insulating panels 6.

[0055] In another preferred variant, the anti-convection cover plates 34 are continuous and completely cover the closure plates 38. Preferably, the anti-convection cover plates 34 are flush with the internal plates 31 of the primary insulating panels 6, including when they pass over the closure plates 38.

[0056] In another variant of the embodiment, schematically illustrated on the figure 12The anti-convection plates 34 are L-shaped, meaning that a single anti-convection cover plate 34 covers two adjoining edges of the inner plate 30 of the same primary insulation panel 6 and is therefore located directly above the spaces 8 formed by said primary insulation panel 6 and two adjacent primary insulation panels 6. The inner plates 31 of the primary insulation panels 6 thus accommodate two anti-convection cover plates in such a way that, progressively, the spaces 8 are all obstructed.

[0057] In an illustrated variant on the figure 5The anti-convection cover plate 34 is folded so that a central portion 41 of the anti-convection cover plate 34, connecting the two edges 36, is housed in the space 8 separating the adjacent primary insulation panels 6. Alternatively, the second edge of the cover plate 34 could rest along the lateral face of the second primary insulation panel 6 without protruding from the space 8.

[0058] THE figures 6 to 10 illustrate different variants of an embodiment of the invention.

[0059] This method of implementation differs from figures 3 to 5in that the anti-convection cover plate 34 is replaced by an anti-convection filling strip 37 housed in space 8. Identical elements or elements performing the same function as those described above have the same reference numbers. Such an anti-convection strip is preferably compressible. This anti-convection strip is inserted into space 8 between the primary insulation panels 6 after the installation of said primary insulation panels 6 on the secondary sealing membrane 4. For this purpose, the anti-convection strip is, if necessary, compressed in its thickness in order to be inserted between the primary insulation panels 6, possibly by force.

[0060] This anti-convection filling strip 37 can be made in many ways. In one embodiment, which is not part of the invention, the anti-convection filling strip 37 can be made of a porous material forced into the space 8 to provide significant prestress, allowing it to compensate for changes in the dimensions of the space 8. Such an anti-convection filling strip 37 made of porous material is particularly suitable for large spaces 8, for example, between 10 mm and 100 mm. Such a porous material could, for example, be glass wool, ideally made of overlapping layers.

[0061] However, as explained above with regard to the figure 1The space 8 between two primary insulation panels 6 can be relatively narrow, typically on the order of 4 mm plus or minus 3 mm. Such a small space cannot be reliably filled by inserting a very thin insulating strip, unlike the gaps 12 between secondary insulation panels 2. Indeed, the roughness of the primary insulation panels 6 could damage such a very thin insulating strip during its insertion. This roughness is, among other things, due to the presence of glass fibers in the insulating foam layer 29 of the primary insulation panels 6.Thus, in a solution that is not part of the invention, sheets of waterproof materials (not illustrated) are incorporated between the layers of glass wool, in order to split the overall volume of the anti-convection filling strip 37 into separate layers undergoing only a modest thermal gradient and exhibiting sufficient resistance to allow the insertion of the anti-convection filling strip 37 without degradation in space 8.

[0062] There figure 6 illustrates an embodiment of the anti-convection filling strip 37. The anti-convection filling strip 37 has a multilayer structure comprising a compressible core 42. Thus, on the figure 6illustrating an example of embodiment, the anti-convection filling strip 37 comprises two sheets 43 each having a rim 44 housed in a respective groove 35 of the primary insulating panels 6. This rim 44 is stapled into the groove 35 thus allowing said rims 44 to remain in the grooves 35 including when changing the dimensions of the space 8 between the primary insulating panels 6, for example during contractions related to the insertion of LNG into the tank.

[0063] Each sheet 43 extends within the space 8 between the primary insulation panels 6, along said primary insulation panels 6, from the groove 35 towards the secondary waterproofing membrane 4. The two sheets 43 are joined by the compressible core 42, which is housed within the space 8 between the primary insulation panels 6. The sheets 43 and the compressible core 42 are made of waterproof materials, for example, a plastic material (PEI, PVC, etc.), cardboard, thick laminated paper, or similar. These sheets 43 and the compressible core 42 can thus be inserted along the primary insulation panels 6 without being damaged by the roughness of said panels 6, even in cases of a narrow space 8.

[0064] The compressible core 42 of the anti-convection filling strip 37 can be made in many ways. In the example shown on the figures 6 and 7The compressible core 42 has a honeycomb structure consisting of a row of cells extending along each of the sheets 43 in the space 8 between the primary insulating panels 6, each cell being fixed to said two sheets 43 in order to structurally link said sheets 43. Other examples of compressible cores 42 are illustrated opposite the figures 8 and 9 .

[0065] THE figures 7 to 8 illustrate a variant embodiment of the anti-convection filling strip 37. This variant differs in that the sheets 43 of the anti-convection filling strip 37 do not have a rim 44 and the primary insulating panels 6 do not have grooves 35. Thus, the anti-convection filling strip 37 is directly housed and extends in the space 8 between the primary insulating panels 6.

[0066] In the example shown on the figure 8, the compressible core 42 is formed of a plurality of tubes 46 spacing the two sheets 43 and extending in the space 8 along the primary insulating panels 6.

[0067] In the example shown on the figure 9 , the compressible core 42 consists of a plurality of spacers 47 developing between the two sheets 43 and delimiting a plurality of rectangular section cells 48 developing in space 8 along the primary insulating panels 6.

[0068] There Figure 10 illustrates a variant embodiment of the anti-convection filling strip 37. This variant differs in that the anti-convection filling strip 37 is not a multilayer structure but a simple corrugated sheet 45. Such a corrugated sheet 45 separates the space 8 between the primary insulating panels 6 into a plurality of cells developing continuously along said panels 6.

[0069] The contour shape of the primary insulating panels 6 and secondary insulating panels 2 described above is generally rectangular, but other contour shapes are possible, including hexagonal shapes to cover flat walls or adapted contour shapes, possibly irregular, to cover special areas of the tank.

[0070] With reference to the figure 11A cutaway view of a methane tanker 70 shows a sealed and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the ship. The wall of the tank 71 comprises a primary sealing membrane intended to be in contact with the LNG contained in the tank, a secondary sealing membrane arranged between the primary sealing membrane and the double hull 72 of the ship, and two insulating barriers arranged respectively between the primary sealing membrane and the secondary sealing membrane and between the secondary sealing membrane and the double hull 72.

[0071] As is known per se, loading / unloading pipelines 73 arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a marine or port terminal to transfer a cargo of LNG to or from the tank 71.

[0072] There figure 11Figure 75 represents an example of a marine terminal comprising a loading and unloading berth, a subsea pipeline, and an onshore facility. The loading and unloading berth is a fixed offshore installation comprising a movable arm, a boom, and a tower, a tower, and a support, a boom. The boom carries a bundle of insulated flexible hoses, a hose, and a hose ...The subsea pipeline 76 allows the transfer of liquefied gas between the loading or unloading station 75 and the onshore facility 77 over a long distance, for example 5 km, which allows the LNG carrier 70 to be kept a long distance from the coast during loading and unloading operations.

[0073] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the land installation 77 and / or pumps equipping the loading and unloading station 75 are used.

[0074] Although the invention has been described in connection with several particular embodiments, it is clearly evident that it is by no means limited to them 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, as defined by the claims.

[0075] The use of the verb "comporter", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

[0076] In claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

1. A sealed and thermally insulating tank for storing a fluid, wherein a flat tank wall comprises, successively in a thickness direction, a secondary thermal insulation barrier (1) comprising a plurality of juxtaposed secondary insulating elements (2), the secondary insulating elements being retained against a support wall (3), a secondary sealing membrane (4) supported by the secondary insulating elements (2) of the secondary thermal insulation barrier (1), a primary thermal insulation barrier (5) comprising a plurality of juxtaposed primary insulating elements (6), the primary insulating elements being retained against the secondary sealing membrane (4), and a primary sealing membrane (7) supported by the primary thermal insulation barrier (5) and intended to be in contact with the cryogenic fluid contained in the tank, wherein the primary insulating elements (6) comprise flat parallelepiped insulating panels disposed so as to provide voids (8) between them, the primary thermal insulation barrier (5) further comprising an anti-convective filler plate (37) disposed in the void between a first flat parallelepiped insulating panel (6) and a second flat parallelepiped insulating panel, the second parallelepiped insulating panel being adjacent to the first parallelepiped insulating panel, the void being defined between a first lateral face of the first flat parallelepiped insulating panel and a second lateral face of the second flat parallelepiped insulating panel, the second lateral face being parallel to the first lateral face, characterized in that the filler plate has a sandwich structure comprising two parallel continuous sheets spaced apart by said elongated wall elements (42, 45, 46, 47), said first parallel continuous sheet being arranged against the first lateral face of the first parallelepiped insulating panel and the second parallel continuous sheet being arranged against the second lateral face of the second parallelepiped insulating panel, the anti-convective filler plate (37) having a length substantially equal to the length of the first and second lateral faces between which the void is formed, the anti-convective filler plate (37) being made of thin continuous material and having a plurality of elongated wall elements (42, 45, 46, 47) extending over substantially the entire width of the void, the elongated wall elements (42, 46, 47) being spaced apart in the thickness direction of the flat tank wall to delimit cells (48) mutually spaced in the thickness direction of the flat tank wall, wherein each cell is substantially extending perpendicular to the thickness direction, the width of the cells being equal to the width of the void minus the thickness of the first and second parallel continuous sheets .

2. The tank as claimed in claim 1, wherein the elongated wall elements are formed by cylindrical elements (42, 46) extending substantially perpendicular to the thickness direction and fixed between the two parallel continuous sheets.

3. The tank as claimed in claim 1, wherein at least one of the two parallel continuous sheets (43) spaced apart by said elongated wall elements comprises an upper edging portion (44) folded and fixed on the internal face of at least one of the two parallelepiped insulating panels (6) between which the void is formed.

4. The tank as claimed in claim 4, wherein the internal face of the first and / or of the second parallelepiped insulating panel (6) comprises a countersink (35) along the void for accommodating said upper edging portion (44) of the continuous sheet.

5. A sealed and thermally insulating tank for storing a fluid, wherein a flat tank wall comprises, successively in a thickness direction, a secondary thermal insulation barrier (1) comprising a plurality of juxtaposed secondary insulating elements (2), the secondary insulating elements being retained against a support wall (3), a secondary sealing membrane (4) supported by the secondary insulating elements (2) of the secondary thermal insulation barrier (1), a primary thermal insulation barrier (5) comprising a plurality of juxtaposed primary insulating elements (6), the primary insulating elements being retained against the secondary sealing membrane (4), and a primary sealing membrane (7) supported by the primary thermal insulation barrier (5) and intended to be in contact with the cryogenic fluid contained in the tank, wherein the primary insulating elements (6) comprise flat parallelepiped insulating panels disposed so as to provide voids (8) between them, the primary thermal insulation barrier (5) further comprising an anti-convective filler plate (37) disposed in the void between a first flat parallelepiped insulating panel (6) and a second flat parallelepiped insulating panel, the second parallelepiped insulating panel being adjacent to the first parallelepiped insulating panel, the anti-convective filler plate (37) being made of a thin continuous material and comprising a plurality of elongated wall elements (42, 45, 46, 47) extending across substantially the entire width of the void to define cells (48) extending substantially perpendicular to the thickness direction, characterized in that the elongated wall elements are formed from successive portions of a sheet of corrugated material (45) having alternated parallel corrugations extending substantially perpendicular to the thickness direction.

6. The tank as claimed in one of claims 1 to 5, wherein the width of the void (8) between the first parallelepiped insulating panel and the second parallelepiped insulating panel (6) is less than 10 mm.

7. The tank as claimed in any one of claims 1 to 6, wherein the anti-convective filler plate (37) is made of flexible material, selected from paper, cardboard and plastic film so that the cells can be easily crushed in the widthwise direction of the void.

8. A vessel (70) for transporting a fluid, the vessel comprising a double hull (72) and a tank (71) as claimed in any one of claims 1 to 7 disposed in the double hull.

9. A transfer system for a fluid, the system comprising a vessel (70) as claimed in claim 8, insulated pipelines (73, 79, 76, 81) arranged so as to connect the tank (71) installed in the hull of the vessel to a floating or onshore storage installation (77) and a pump for conveying a fluid through the insulated pipelines, from or to the floating or onshore storage installation, to or from the tank of the vessel.

10. A method for loading or offloading a vessel (70) as claimed in claim 8, wherein a fluid is routed through insulated pipelines (73, 79, 76, 81), from or to a floating or onshore storage installation (77), to or from the tank of the ship (71).

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