EP3679289B1 - Sealed and thermally insulating tank with anti-convective filling element - Google Patents

Description

Technical area

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

Sealed and thermally insulating membrane tanks are used in particular for the storage of 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 vessel may be intended for the transport of liquefied natural gas or to receive liquefied natural gas serving as fuel for the propulsion of the floating structure.

Technological background

In the state of the art, sealed and thermally insulating tanks are known for storing liquefied natural gas, integrated into a supporting structure, such as the double hull of a ship intended for transporting liquefied natural gas. Generally, such tanks comprise a multilayer structure having successively, in the direction of the thickness, from the outside to the inside of the tank, a secondary thermal insulation barrier retained in the supporting structure, a waterproofing membrane. secondary resting against the secondary thermal insulation barrier, a primary thermal insulation barrier resting against the secondary waterproofing membrane and a primary waterproofing membrane resting against the primary thermal insulation barrier and intended to be in contact with the liquefied natural gas contained in the tank.

The document WO2016 / 046487 discloses a secondary thermal insulation barrier and a primary thermal insulation barrier formed from juxtaposed insulating panels. In this document WO2016 / 046487 , the secondary waterproofing membrane consists of a plurality of metal sheets comprising corrugations projecting outwards from the tank and thus allowing the secondary waterproofing membrane to deform under the effect of thermal and mechanical stresses generated by the fluid stored in the tank. An internal face of the insulating panels of the secondary thermal insulation barrier has grooves receiving the corrugations of the corrugated metal sheets of the secondary waterproof membrane. These corrugations and these grooves form a mesh of channels developing along the walls of the tank.

KR 2016 0015 438 A discloses a tank according to the preamble of claim 1.

Abstract

An idea underlying the invention is to provide a sealed and thermally insulating tank with a waterproofing membrane comprising corrugations in which the convection phenomena are reduced. In particular, an idea at the basis of the invention is to provide a sealed and thermally insulating tank limiting the presence of continuous circulation channels in the thermal insulation barriers in order to limit the phenomena of natural convection in said insulation barriers. thermal.

According to one embodiment, the invention provides a sealed and thermally insulating 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 members, a secondary waterproofing membrane carried by the secondary insulating elements of the secondary thermal insulation barrier, a secondary barrier primary thermal insulation comprising a plurality of juxtaposed primary insulating elements, the primary insulating elements being retained against the secondary waterproofing membrane, for example by primary retaining members, and a primary waterproofing membrane carried by the barrier of primary thermal insulation and intended to be in contact with the cryogenic fluid contained in the vessel ,
in which the secondary waterproofing membrane is a corrugated metal membrane comprising a series of parallel corrugations forming channels, in particular channels of great length depending on the dimensions of the tank, and flat portions located between said corrugations, the primary insulating elements having an external face, said external face possibly being planar, covering the flat portions of the secondary waterproofing membrane, the secondary insulating elements having an internal face, possibly planar, supporting the planar portions of the secondary waterproofing membrane, anti-convective filling elements being arranged in corrugations of the secondary waterproofing membrane to create a pressure drop in said channels.

Thanks to these characteristics, it is possible to limit the convection phenomena along the corrugations of the secondary waterproofing membrane, in particular in the vessel walls which have a vertical or oblique orientation in the field of gravity, in which a gradient temperature between the upper part and the lower part of the wall is likely to favor such a phenomenon.

According to one embodiment, the corrugations of the secondary waterproofing membrane protrude outwardly from the tank in the direction of the supporting structure.

According to one embodiment, the anti-convective filling elements arranged in the corrugations of the secondary waterproofing membrane are covered by the external face of the primary insulating elements.

According to one embodiment, the anti-convective filling elements arranged in the corrugations of the secondary waterproofing membrane are fixed to the external face of the primary insulating elements.

According to one embodiment, the anti-convective filling elements arranged in the corrugations of the secondary waterproofing membrane are fixed, for example glued, to the secondary waterproofing membrane.

According to one embodiment, the secondary insulating elements have grooves hollowed out in the internal face to receive corrugations from the secondary waterproofing membrane, additional anti-convective filling elements being arranged in said grooves between the membrane. secondary sealing and the secondary insulating elements to create a pressure drop in a remaining portion of said grooves located around the corrugations of the secondary sealing membrane.

According to one embodiment, the corrugations of the secondary waterproofing membrane project towards the interior of the tank.

According to one embodiment, the anti-convective filling elements arranged in the corrugations of the secondary waterproofing membrane are supported by the internal face of the secondary insulating elements.

According to one embodiment, the primary insulating elements have grooves hollowed out in the external face to receive corrugations from the secondary waterproofing membrane, additional anti-convective filling elements being arranged in said grooves between the secondary waterproofing membrane. and the primary insulating elements to create a pressure drop in a remaining portion of said grooves located around the corrugations of the secondary waterproofing membrane.

According to one embodiment, the primary waterproofing membrane is a corrugated metal membrane comprising a series of parallel corrugations forming channels, in particular channels of great length depending on the dimensions of the tank, and flat portions located between said corrugations, the primary insulating elements having an internal face supporting the flat portions of the primary waterproofing membrane.

According to one embodiment, the corrugations of the primary waterproofing membrane project outwardly from the tank in the direction of the supporting structure.

According to one embodiment, the primary insulating elements have grooves hollowed out in the internal face to receive corrugations from the primary waterproofing membrane, additional anti-convective filling elements being arranged in said grooves between the primary waterproofing membrane. and the primary insulating elements to create a pressure drop in a remaining portion of said grooves located around the corrugations of the primary waterproofing membrane.

According to one embodiment, the anti-convective filling elements comprise an elongated filling part arranged in a corrugation of the secondary sealing membrane, and / or of the primary sealing membrane, the elongated filling part having a shape. of section which fills at least 80% of the section of the corrugation in the assembled state of the tank, and for example the entire section of the corrugation. The elongated filling piece can have many cross-sectional shapes. For example, the elongated filling piece may have a cross-sectional shape complementary to the cross-sectional shape of the corrugation or else a circular, elliptical or other cross-sectional shape.

According to one embodiment, the filling part arranged in a corrugation comprises parallel grooves oriented transversely to the length of the filling part and distributed along the length of the filling part.

According to one embodiment, the secondary waterproofing membrane, and / or the primary waterproofing membrane, comprises a first series of parallel corrugations and a second series of parallel corrugations which is transverse to the first series of corrugations and which intersects the first set of corrugations at node areas, anti-convective fillers having node pieces disposed in node areas of the secondary waterproofing membrane, and / or the primary waterproofing membrane .

According to one embodiment, an anti-convective filling element or a complementary anti-convective filling element is made of expanded polystyrene or of polymer foam or of glass wool.

According to one embodiment, an anti-convective filling element or a complementary anti-convective filling element is made of flexible synthetic material or of molded synthetic material.

According to one embodiment, at least one corrugation of the secondary waterproofing membrane in which an anti-convective filling element is arranged is arranged in line with a primary insulating element and at a distance from primary insulating elements adjacent to said insulating element. primary.

According to one embodiment, the secondary waterproofing membrane and / or the primary waterproofing membrane comprises a plurality of corrugated metal plates. According to one embodiment, each corrugated metal plate of the secondary waterproofing membrane comprises one or more corrugations of the series of corrugations.

According to one embodiment, a corrugated metal plate of the secondary waterproofing membrane is carried by at least two adjacent secondary insulating elements.

According to one embodiment, the secondary waterproofing membrane and / or the primary waterproofing membrane has a thickness of between 0.7mm and 1.2mm so as to have a rigidity that does not allow the deformation of the corrugations under the effect of its own weight.

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, in particular an LNG vessel, LNG carrier, a floating storage and regasification unit ( FSRU), a floating production and remote storage unit (FPSO) and others.

According to one embodiment, a ship for transporting a cold liquid product comprises a double hull and a said tank arranged in the double hull.

According to one embodiment, the invention also provides a method for loading or unloading such a vessel, in which a fluid is conveyed through isolated pipes from or to a floating or terrestrial storage installation to or from the tank of the vessel. ship.

According to one embodiment, the invention also provides a transfer system for a fluid, the system comprising the aforementioned vessel, isolated pipes arranged so as to connect the tank installed in the hull of the vessel to a floating or land storage installation. and a pump for driving a fluid through insulated pipelines from or towards the floating or terrestrial storage facility to or from the vessel of the vessel.

Brief description of the figures

• La figure 1 est une vue en perspective, écorchée, d'une paroi de cuve étanche et thermiquement isolante de stockage d'un fluide ;
• La figure 2 est une vue partielle en perspective de la section II-II de la figure 1 illustrant un premier mode de réalisation de l'invention ;
• La figure 3 est une vue en perspective schématique de dessous d'un panneau isolant de la barrière d'isolation thermique primaire selon une variante de réalisation du premier mode de réalisation de l'invention ;
• La figure 4 est une vue partielle en perspective de la section II-II de la figure 1 illustrant un deuxième mode de réalisation de l'invention ;
• La figure 5 est une vue en perspective schématique d'un exemple de barreau de remplissage ;
• La figure 6 est une vue en coupe illustrant le deuxième mode de réalisation de l'invention selon la coupe III-III de la figure 1 ;
• La figure 7 représente une vue en coupe d'une paroi de cuve étanche et thermiquement isolante selon un troisième mode de réalisation de l'invention.
• La figure 8 est une représentation schématique écorchée d'une cuve de navire méthanier et d'un terminal de chargement/déchargement de cette cuve.

The invention will be better understood, and other aims, details, characteristics and advantages thereof will emerge more clearly during the following description of several particular embodiments of the invention, given solely by way of illustration and not by way of limitation. , with reference to the accompanying drawings.

• The figure 1 is a perspective view, cut away, of a sealed and thermally insulating tank wall for storing a fluid;
• The figure 2 is a partial perspective view of section II-II of the figure 1 illustrating a first embodiment of the invention;
• The figure 3 is a schematic perspective view from below of an insulating panel of the primary thermal insulation barrier according to an alternative embodiment of the first embodiment of the invention;
• The figure 4 is a partial perspective view of section II-II of the figure 1 illustrating a second embodiment of the invention;
• The figure 5 is a schematic perspective view of an example of a filling bar;
• The figure 6 is a sectional view illustrating the second embodiment of the invention according to section III-III of the figure 1 ;
• The figure 7 shows a sectional view of a sealed and thermally insulating tank wall according to a third embodiment of the invention.
• The figure 8 is a cut-away schematic representation of an LNG vessel tank and a loading / unloading terminal for this tank.

Detailed description of embodiments

By convention, the terms “external” and “internal” are used to define the relative position of an element with respect to another, by reference to the interior and exterior of the tank.

On the figure 1 , there is shown the multilayer structure of a sealed and thermally insulating tank wall for storing a fluid.

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

The supporting structure 3 can in particular be a self-supporting metal sheet or, more generally, any type of rigid partition having suitable mechanical properties. The supporting structure 3 can in particular be formed by the hull or the double hull of a ship. The supporting structure 3 comprises a plurality of walls defining the general shape of the tank, usually a polyhedral shape.

The secondary insulating panels 2 have substantially the shape of a rectangular parallelepiped. The secondary insulating panels 2 each comprise an insulating lining 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 boards bonded to said layer of insulating polymer foam 9. The insulating polymer foam can in particular be a polyurethane-based foam. The polymer foam is advantageously reinforced with glass fibers helping to reduce its thermal contraction.

The secondary insulating panels 2 are juxtaposed in parallel rows and separated from each other by interstices 12 guaranteeing a functional assembly play. The interstices 12 are filled with a heat-insulating lining 13, shown on the figures 1 and 7 , such as glass wool, rock wool or flexible synthetic foam with open cells for example. The heat-insulating lining 13 is advantageously made of a porous material so as to allow a circulation of gas in the interstices 12 between the secondary insulating panels 2, for example a circulation of inert gas, such as nitrogen, within the barrier of secondary thermal insulation 1 so as to keep it under an inert atmosphere and thus prevent combustible gas from being in an explosive concentration range and / or in order to place the secondary thermal insulation barrier 1 in negative pressure in order to increase its insulating power. This gas circulation is also important to facilitate the detection of possible fuel gas leaks. The interstices 12 have, for example, a width of the order of 30 mm.

The internal plate 10 has two series of grooves 14, 15, perpendicular to one another, so as to form a network of grooves. Each of the series of grooves 14, 15 is parallel to two opposite sides of the secondary insulating panels 2. The grooves 14, 15 are intended to receive corrugations 25, 26, projecting outwardly of the vessel, formed on metal sheets 24 of the secondary waterproofing membrane 4. In the embodiment shown in FIG. figure 1 , the internal plate 10 comprises three grooves 14 extending in the longitudinal direction of the secondary insulating panel 2 and nine grooves 15 extending in the transverse direction of the secondary insulating panel 2.

Furthermore, the internal plate 10 is equipped with metal plates 17, 18 for anchoring the edge of the corrugated metal sheets 24 of the secondary waterproofing membrane 4 on the secondary insulating panels 2. The metal plates 17, 18 extend in two perpendicular directions which are each parallel to two opposite sides of the secondary insulating panels 2. The metal plates 17, 18 are fixed to the internal plate 10 of the secondary insulating panel 2, by screws, rivets or staples, for example. The turntables 17, 18 are placed in recesses made in the internal plate 10 so that the internal surface of the metal plates 17, 18 is flush with the internal surface of the internal plate 10. The internal plate 10 has an internal surface which is substantially flat, outside any singular zones such as the grooves 14, 15 or the countersinks making it possible to accommodate the metal plates 17, 18.

The internal plate 10 is also equipped with threaded studs 19 projecting towards the inside of the tank, and intended to ensure the fixing of the primary thermal insulation barrier 5 on the secondary insulation panels 2 of the secondary thermal insulation barrier. 1. The metal studs 19 pass through holes made in the metal plates 17.

The secondary waterproofing membrane 4 comprises a plurality of corrugated metal sheets 24 each having a substantially rectangular shape. The corrugated metal sheets 24 are arranged offset from the secondary insulating panels 2 of the secondary thermal insulation barrier 1 such that each of said corrugated metal sheets 24 jointly extend over four adjacent secondary insulating panels 2.

Each corrugated metal sheet 24 has a first series of parallel corrugations 25 extending in a first direction and a second series of parallel corrugations 26 extending in a second direction. The directions of the series of corrugations 25, 26 are perpendicular. Each of the series of corrugations 25, 26 is parallel to two opposite edges of the corrugated metal sheet 24. The corrugations 25, 26 protrude outward from the vessel, that is to say in the direction of the supporting structure. 3. The corrugated metal sheet 24 has between the corrugations 25, 26 a plurality of flat surfaces. At the level of each crossing between two corrugations 25, 26 the metal sheet 24 comprises a node zone 27.

The corrugations 25, 26 of the corrugated metal sheets 24 are housed in the grooves 14, 15 formed in the internal plate 10 of the secondary insulating panels 2. The adjacent corrugated metal sheets 24 are welded together. with overlap. The anchoring of the corrugated metal sheets 24 on the metal plates 17, 18 is carried out by tack welds.

The corrugated metal sheets 24 are, for example, made of Invar®: that is to say an alloy of iron and nickel, the coefficient of expansion of which is typically between 1.2.10 ^-6 and 2.10 ^-6 K ^-1 , or in an iron alloy with a high manganese content, the coefficient of expansion of which is typically of the order of 7.10 ^-6 K ^-1 . Alternatively, the corrugated metal sheets 24 can also be made of stainless steel or aluminum.

The primary thermal insulation barrier 5 comprises a plurality of primary insulating panels 6 of substantially rectangular parallelepiped shape. The primary insulating panels 6 are here offset from the secondary insulating panels 2 of the secondary thermal insulation barrier 1 such that each primary insulating panel 6 extends over four secondary insulating panels 2 of the secondary thermal insulation barrier 1. The adjacent primary insulating panels 6 are spaced apart by a space 8 ensuring a functional clearance for mounting said primary insulating panels 6. However, this space 8 is reduced compared to the gap 12 between two adjacent secondary insulating panels 2 of the secondary thermal insulation barrier 1. Thus, the space 8 separating two primary insulation panels 6 from the primary thermal insulation barrier 5 is of the order of 4mm plus or minus 3mm.

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 a layer of insulating lining such as a layer of insulating polymer foam 29 sandwiched. between two rigid plates, internal 30 and external 31, for example in 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 waterproofing membrane 7 in a similar way to the metal plates 17, 18 allowing the anchoring of the Corrugated metal sheets 24 of the secondary waterproofing membrane 4. Likewise, the internal 30 and external 31 plates are preferably flat, outside any singular zones.

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 comprises two series of corrugations 40 perpendicular to each other. . The corrugations 40 of each of said series of corrugations 40 are parallel to a respective side of the corresponding corrugated metal sheet 39. In the embodiment illustrated in figure 1 , the corrugations 40 protrude towards the interior of the tank. The corrugated metal sheets 39 are, for example, made of stainless steel or aluminum.

Other details and other embodiments, in particular on the secondary 1 and primary 5 thermal insulation barriers, the anchoring members of the thermally insulating barriers 1 and 5 and the waterproofing membranes 4 and 7, can be found in the document WO2016 / 046487 , the document WO2013004943 or the document WO2014057221 .

In such a tank, the corrugations 25, 26 of the secondary waterproofing membrane 4 constitute a mesh of circulation channels. Such channels develop continuously between the secondary waterproofing membrane 4 and the primary thermal insulation barrier 5 throughout the vessel wall. Such channels thus promote convection movements, in particular on the walls of tanks having a large vertical component, such as the transverse walls of the tank. This mesh of continuous channels can generate thermosyphon phenomena in the primary thermal insulation barrier 5. One aspect of the invention starts from the idea of preventing these convective movements in the walls of the vessel.

The figure 2 shows a partial perspective view of section II-II of the figure 1 at a crossing between corrugations 25, 26 of the secondary waterproofing membrane 4 according to a first embodiment of the invention. The elements which are identical or fulfill the same function as those described above have the same figures. reference.

On this figure 2 , only two corrugations 25 of the first series of corrugations 25 and two corrugations 26 of the second series of corrugations 26 are illustrated, these corrugations 25, 26 forming at their intersections nodes 27 of the secondary waterproofing membrane 4. The The description below for these corrugations 25, 26 and nodes 27 applies by analogy to all the corrugations 25, 26 and to all the nodes 27 of the secondary waterproof membrane 4.

One aspect of the invention starts from the idea of limiting the length of the channels formed by the corrugations 25, 26 of the secondary waterproof membrane 4. According to the first embodiment of the invention, the filling blocks 16 of insulating lining. are inserted into one, some, or all of the nodes 27 of the secondary waterproofing membrane 4. These filling blocks 16 are arranged in the nodes 27 on an internal face of the corrugated metal sheets 24 so as to be arranged between the membrane d 'secondary seal 4 and the primary thermal insulation barrier 5. On the figure 2 , such a filling block 16 is placed in each node 27 of the secondary waterproofing membrane 4.

Such a filling block 16 takes the form of an insulating block in the shape of a cross developing in the node 27 in which it is inserted and projecting into portions of the grooves 25, 26 forming said node 27. In addition, such a block filling 16 has a section of complementary shape to the shapes of the node 27 and portions of the grooves 25, 26 in which said filling block 16 is inserted. In this first embodiment, the filling blocks 16 are inserted into the nodes 27 and the portions of the corresponding corrugations 25, 26 after the installation of the secondary waterproofing membrane 4 on the secondary thermal insulation barrier 1 and beforehand. the installation of the primary insulating panels 6 on the secondary waterproofing membrane 4.

The filling block 16 can be made of any material allowing a pressure drop in the channels formed by the corrugations 25, 26. Thus, the filling blocks 16 can be made, for example, of foam, of felt, of wool. glass, wood or others.

Preferably, the filling blocks 16 are formed in a flexible foam allowing its compression. Such a flexible foam makes it possible to size the filling blocks 16 with dimensions slightly greater than the dimensions of the nodes 27 and of the portions of the corrugations 25, 26 in order to accommodate the filling blocks 16 in said nodes 27 and portions of the corrugations 25, 26 with a slight compression of said filling blocks 16 in order to match the shapes of the node 27 as closely as possible.

Further, the filler blocks 16 are preferably made from an open cell foam. Such an open-cell foam makes it possible to limit the phenomenon of convection by producing a pressure drop in the thermal movements within the channels formed by the corrugations 25, 26 while allowing the circulation of gas such as an inert gas within the chamber. the primary thermal insulation barrier 5 as explained above for the padding 13.

Thus, the filling blocks 16 form plugs limiting the length of the channels formed by the corrugations 25, 26. Typically, each corrugation forms a plurality of discontinuous channels each formed by a section of said corrugation 25, 26 lying between two successive nodes 27. . Such channels limited to the sections of the corrugations 25, 26 located between two adjacent nodes 27 do not allow the creation of a significant convection phenomenon and, in particular, prevent the creation of a thermosyphon phenomenon.

In embodiments not shown, filler blocks 16 are arranged in some nodes 27 only and not in all nodes 27. Thus, for example, such filler blocks 16 are arranged in all nodes 27 adjacent to the edges. corrugated metal sheet 24 forming said nodes 27. In another example, only one node 27 out of two or three along a corrugation 25 and / or 26 is filled by a filling block 16.

The figure 3 is a schematic perspective view from below of a primary insulating panel 6 of the primary thermal insulation barrier 5 according to an alternative embodiment of the first embodiment of the invention. The elements identical or fulfilling the same function as those described above have the same reference figures.

In this variant of the first embodiment of the invention, the filling blocks 16 are formed by studs 20 arranged on an outer face of the outer plate 31 of the primary insulating panels 6, that is to say on the face external plates 31 opposite the layer of insulating polymer foam 29 of said panels 6. Such pads 20 are made of any suitable material such as the materials mentioned above for the production of the filling block 16 in the shape of a cross. On the figure 3 , these studs take the form of a block of flexible foam with an open cell of cylindrical shape. Such pads 20 are fixed to the outer plate 31 by any suitable means, for example by gluing, stapling, double-sided tape or the like. This step of fixing the studs 20 on the primary insulating panels 6 can thus advantageously be carried out during the manufacture of said primary insulating panels 6, that is to say prior to the manufacture of the tank.

The pads 20 are arranged on the outer plate 31 so as to be inserted into the nodes 27 when the primary insulating panels 6 are positioned on the secondary waterproofing membrane 4. Thus, the figure 3 schematically illustrates the corrugations 25, 26 forming a mesh 21 of corrugations 25, 26 of the secondary waterproofing membrane 4 under the primary thermal insulation barrier 5. As illustrated in FIG. figure 3 , the pads 20 are arranged on the outer plate 31 so as to be each located at a node 27 formed by the intersection of corrugations 25 and 26 of the secondary waterproofing membrane 4.

Thus, unlike the filling blocks 16 in the form of a cross inserted into the nodes 27 prior to the installation of the primary insulating panels 6 as described above with regard to the figure 2 , this variant of the first embodiment does not require a step of installing the filling blocks in the nodes 27, the pads being directly inserted into said nodes 27 during the positioning of the primary insulating panels 6 in the tank.

The figure 3 illustrates four pads 20 each to be inserted into a respective node 27. However, analogously to filler blocks 16 and such as explained above, the number and arrangement of said pads 20 can be modified to fill all or only some of the nodes 27.

The figure 4 is a partial perspective view of section II-II of the figure 1 according to a second embodiment of the invention. Elements which are identical or perform the same function as those described above have the same reference numbers.

This second embodiment differs from the first embodiment in that the sections of the corrugations 25, 26 located between two successive nodes 27 are also filled with a heat-insulating lining. Thus, in addition to the cross-shaped filling blocks 16 housed in the nodes 27, the vessel has filling bars 22 housed in the sections of the corrugations 25, 26 located outside the nodes 27. Such filling bars 22 can be used. made of materials such as those described above opposite the filling blocks 16 in the shape of a cross. Advantageously, the bars of 22 are made of a material allowing the circulation of inert gas in the corrugations 25, 26 while generating a pressure drop in thermal circulation flows within the corrugations 25, 26 avoiding the creation of thermosyphons by convection in said corrugations 25, 26.

Likewise, these filler bars 22 are dimensioned so as to preferably have a section of complementary shape to the sections of the corrugations 25, 26 in order to obstruct the channels formed by said corrugations 25, 26. These filler bars 22 can also present other shapes, for example a circular shape so as to be compressed by the outer plate 31 of the primary insulating panel 6 disposed above in order to occupy a significant portion of the section of the corresponding corrugation 25, 26, by example at least 80% of said corrugation 25, 26.

Thus, according to a preferred embodiment illustrated in figure 5 , the filling bars 22 are made in the form of bars of 5 to 15 cm having a section corresponding to the complete section of the corrugation 25, 26 in which said bar is inserted. This bar is advantageously produced in Extruded polystyrene with a density of 8 to 30 kg / m ^ 3. Ideally, the bar has an additional height of 1 to 2 / 10th mm corresponding to a crushing in place and a slight thermal contraction. Advantageously, the bar also has a toothing 49 of its profile so that the pressure drop that it generates under increasing flow speeds is significant but the pressure drop at low speed is limited so as not to completely obstruct. the circulation of gas in the corrugations 25, 26.

The figure 6 illustrates a sectional view of a corrugation 25 of the secondary waterproofing membrane 4 housed in a groove 14 of a secondary insulating panel 2 of the secondary thermally insulating barrier according to section III-III of the figure 1 according to an alternative embodiment of the second embodiment of the invention as described with reference to the figure 4 .. Elements which are identical or perform the same function as those described above have the same reference numbers. In addition, the description below with regard to the figure 6 for a corrugation 25 housed in a groove 14 applies by analogy to one or more other grooves 14 and / or 15.

As shown on the figure 6 , the groove 14 completely passes through the thickness of the internal plate 10 and opens out at the level of the insulating polymer foam layer 9. The groove 14 is dimensioned so as to provide a positioning clearance for the corrugation 25 housed in said groove 14 when the corresponding corrugated metal sheet 24 is installed on the secondary insulation panel 2 comprising said groove 14. This clearance must also allow the relative movements between the corrugation and the walls of the groove 14 generated by the differences in contractions and expansions.

Just like the corrugations 25, 26 constitute a mesh of channels favoring by convection the formation of thermosyphon in the primary thermal insulation barrier 5, the grooves 14, 15 form a mesh in the secondary thermal insulation barrier 1 also forming a mesh of channels which may be at the origin of such a phenomenon of thermosyphon by convection.

To avoid this, the variant of the second embodiment differs from the variant described with regard to figure 4 in that it comprises, in addition to the filling blocks 16 in the nodes 27 and the filling bars 22 in the corrugations 25, 26, a third filling block 23 arranged in the grooves 14, 15 of the internal plates 10 of the panels secondary insulators 2.

As shown on the figure 6 , this third filling block 23 is positioned in the grooves 14 in order to generate a pressure drop in the circulation of cold in the mesh formed by the grooves 14, 15. This third filling block 23 is similar to the filling block 16 and to the filling bar 22 and can be made of many materials. Preferably, this padding is made of flexible foam with open cells so as not to prevent the circulation of inert gas and / or the detection of leaks in the secondary thermal insulation barrier 1. This third filling block 23 is installed in the groove. 14 prior to the installation of the corresponding corrugated metal sheet 24.

Preferably, this third filling block 23 is compressible and is compressed by the corrugation 25 of the corrugated metal sheet 24 in order to guarantee its good distribution throughout the groove 14. In particular, it is preferable to use for this. third filling block 23 highly deformable materials (very low density expanded polystyrene (<10kg / m ^ 3), melamine foam, flexible low density polyurethane foam) which are crushed during the installation of the corrugated metal sheet 24 In another embodiment, the third filling block is made in the form of modular elements, in resin or rigid low-density polyurethane foam for example, which are deposited in the groove 14 just before the installation of the metal sheet. corrugated 24, the corrugation of which must be housed in said groove 14.

The figure 6 illustrates the use of the third filling block 23 at the level of a corrugation 25 of the secondary metal sheet 24. However, in the non-illustrated context of a primary waterproofing membrane 7 having outgoing corrugations 40, that is- that is to say protruding outwards from the tank and housed in corresponding grooves made in the internal plates 31 of the primary insulating panels 6, the third filling block 23 can be used in such a way analogous to fill channels formed by said grooves made in the internal plate 31 of the primary insulating panels 6

The figure 7 shows a sectional view of a sealed and thermally insulating tank wall according to a third embodiment of the invention. Elements which are identical or perform the same function as those described above have the same reference numbers.

This third embodiment differs from the second embodiment in that the corrugations 25, 26 of the secondary waterproofing membrane 4 as well as the corrugations 40 of the primary waterproofing membrane 7 are re-entrant corrugations, that is, that is to say protruding towards the interior of the tank. Thus, the grooves 14, 15 accommodating the corrugations 25, 26 of the secondary waterproofing membrane 4 are formed in the outer plates 30 of the primary insulating panels 6. Accordingly, the filler block 16 and the filler bar 22 are arranged. between the corrugated metal sheets 24 and the inner plates 10 of the secondary insulating panels 2. In addition, the third filling block 23 is housed in the grooves 14, 15 made 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 waterproofing membrane 4.

In addition, as shown in the figure 7 , the 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 internal plate 31 of said primary insulating panels 6. An insulating gasket 51 can also be positioned. be positioned in wells made at the corners of the primary insulating panels 6 making it possible to house the anchoring members 19. As with the previous embodiments, it is possible to install a filler block in all or only some of the nodes and / or corrugations of the secondary 4 and / or primary 7 waterproofing membrane and / or grooves housing said corrugations.

The outline shape of the primary insulating panels 6 and secondary insulating panels 2 described above is generally rectangular, but other outline shapes are possible, in particular hexagonal shapes to cover sections. flat walls or suitable contour shapes, possibly irregular, to cover special areas of the tank.

With reference to the figure 8 , a cutaway view of an LNG carrier 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 vessel 71 comprises a primary waterproofing membrane intended to be in contact with the LNG contained in the vessel, a secondary waterproofing membrane arranged between the primary waterproofing membrane and the double hull 72 of the vessel, and two insulating barriers arranged respectively between the primary waterproofing membrane and the secondary waterproofing membrane and between the secondary waterproofing membrane and the double shell 72.

In a manner known per se, loading / unloading pipes 73 arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a maritime or port terminal for transferring a cargo of LNG from or to the tank 71.

The figure 8 shows an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipe 76 and an onshore installation 77. The loading and unloading station 75 is a fixed off-shore installation comprising a movable arm 74 and a tower 78 which supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading / unloading pipes 73. The movable arm 74 can be swiveled and adapts to all sizes of LNG carriers. A connecting pipe (not shown) extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore installation 77. The latter comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the underwater pipe 76 to the loading or unloading station 75. The underwater pipe 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the shore installation 77 over a great distance, for example 5 km, which makes it possible to keep the LNG carrier 70 at a great distance from the coast during loading and unloading operations.

To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps fitted to the shore installation 77 and / or pumps fitted to the loading and unloading station 75 are used.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it comprises all the technical equivalents of the means described as well as their combinations if these come within the scope of the invention, as defined by the claims.

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

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

Claims (16)

1. A sealed and thermally insulating tank for storing a fluid, wherein a 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 (2) 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 (6) 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 secondary sealing membrane (4) is a corrugated metal membrane comprising a series of parallel corrugations (25, 26) forming channels and flat portions located between said corrugations (25, 26), the primary insulating elements (6) having an external face covering the flat portions of the secondary sealing membrane (4), the secondary insulating elements (2) having an internal face supporting the flat portions of the secondary sealing membrane (4),

   characterized in that anti-convection filler elements (16, 20, 22) are disposed in the corrugations (25, 26) of the secondary sealing membrane (4) to generate a head loss in said channels.
2. The tank as claimed in claim 1, wherein the corrugations (25, 26) of the secondary sealing membrane (4) project toward the outside of the tank toward the support structure (3),
   and wherein the anti-convection filler elements (16, 20, 22) disposed in the corrugations (25, 26) of the secondary sealing membrane (4) are covered by the external face of the primary insulating elements (6).
3. The tank as claimed in claim 2, wherein the anti-convection filler elements (20) disposed in the corrugations (25, 26) of the secondary sealing membrane (4) are fixed to the external face of the primary insulating elements (6).
4. The tank as claimed in claim 2, wherein the anti-convection filler elements (16, 22) disposed in the corrugations (25, 26) of the secondary sealing membrane (4) are fixed to the secondary sealing membrane (4).
5. The tank as claimed in claims 2 to 4, wherein the secondary insulating elements (2) have grooves (14, 15) hollowed out of the internal face for receiving the corrugations (25, 26) of the secondary sealing membrane (4), with additional anti-convection filler elements (23) being disposed in said grooves (14, 15) between the secondary sealing membrane (4) and the secondary insulating elements (2) to generate a head loss in a remaining portion of said grooves (14, 15) located around the corrugations (25, 26) of the secondary sealing membrane (4).
6. The tank as claimed in claim 1, wherein the corrugations (25, 26) of the secondary sealing membrane (4) project toward the inside of the tank, and wherein the anti-convection filler elements (16, 22) disposed in the corrugations (25, 26) of the secondary sealing membrane (4) are supported by the internal face of the secondary insulating elements (2).
7. The tank as claimed in claim 6, wherein the primary insulating elements (6) have grooves (14, 15) hollowed out of the external face for receiving the corrugations (25, 26) of the secondary sealing membrane (4), with additional anti-convection filler elements (23) being disposed in said grooves (14, 15) between the secondary sealing membrane (4) and the primary insulating elements (6) to generate a head loss in a remaining portion of said grooves (14, 15) located around the corrugations (25, 26) of the secondary sealing membrane (4).
8. The tank as claimed in one of claims 1 to 7, wherein the primary sealing membrane (7) is a corrugated metal membrane comprising a series of parallel corrugations (40) forming channels and flat portions located between said corrugations (40), with the primary insulating elements (6) having an internal face supporting the flat portions of the primary sealing membrane (7),

   wherein the corrugations (40) of the primary sealing membrane (7) project toward the outside of the tank toward the support structure (3),

   and wherein the primary insulating elements (6) have grooves hollowed out of the internal face for receiving the corrugations (40) of the primary sealing membrane (7), with additional anti-convection filler elements being disposed in said grooves between the primary sealing membrane (7) and the primary insulating elements (6) to generate a head loss in a remaining portion of said grooves located around the corrugations (40) of the primary sealing membrane (7).
9. The tank as claimed in one of claims 1 to 8, wherein the anti-convection filler elements comprise an elongated filler part (22) disposed in a corrugation (25, 26) of the secondary sealing membrane (4), the elongated filler part (22) having a section shape that fills at least 80% of the section of the corrugation (25, 26).
10. The tank as claimed in claim 9, wherein the filler part (22) disposed in a corrugation (25, 26) comprises parallel grooves (49) oriented transverse to the length of the filler part (22) and distributed along the length of the filler part (22).
11. The tank as claimed in one of claims 1 to 10, wherein the secondary sealing membrane (4) comprises a first series of parallel corrugations (25) and a second series of parallel corrugations (26), which is transverse to the first series of corrugations (25) and which intersects the first series of corrugations (25) at node zones (27), the anti-convection filler elements comprising node parts (16, 20) disposed in the node zones (27) of the secondary sealing membrane (4).
12. The tank as claimed in one of claims 1 to 11, wherein an anti-convection filler element (16, 20, 22) or an additional anti-convection filler element (23) is made of expanded polystyrene or of polymer foam or of glass wool.
13. The tank as claimed in one of claims 1 to 12, wherein an anti-convection filler element (16, 20, 22) or an additional anti-convection filler element (23) is made of flexible synthetic material or of molded synthetic material.
14. 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 13 disposed in the double hull.
15. A transfer system for a fluid, the system comprising a vessel (70) as claimed in claim 14, 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.
16. A method for loading or offloading a vessel (70) as claimed in claim 14, 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 vessel (71).

Images