WO2023227379A1

WO2023227379A1 - Dome structure for a sealed and thermally insulating tank

Info

Publication number: WO2023227379A1
Application number: PCT/EP2023/062548
Authority: WO
Inventors: Alexandre LEPRONT
Original assignee: Gaztransport Et Technigaz
Priority date: 2022-05-24
Filing date: 2023-05-11
Publication date: 2023-11-30
Also published as: FR3136034A1; TW202413838A; FR3136034B1

Abstract

The invention relates to a dome structure for a sealed and thermally insulating tank, the dome structure having a horizontal cover and a dome side wall comprising a sealing membrane having at least one corrugation, the dome structure having at least one insulating block anchored against a lower face of the cover, the insulating block and the corrugation being, in projection in a horizontal plane, spaced apart by a first distance; an insulating lining having one or more lining elements, the insulating lining being adjacent to the side wall, positioned against the cover and arranged between the insulating block and the side wall, the or each lining element having a thickness in a direction orthogonal to the dome side wall which is less than the first distance, a holding plate being anchored to a lower surface of the insulating block and extending under the insulating lining.

Description

Dome structure for a waterproof and thermally insulating tank

The invention relates to the field of waterproof and thermally insulating tanks, for the storage and/or transport of a fluid, such as a cryogenic fluid. Airtight and thermally insulating tanks are used in particular for the storage of liquefied natural gas (LNG) which is stored, at atmospheric pressure, at approximately -162°C.

Technology background

Document WO 2019/215414 discloses a liquefied gas storage installation comprising a supporting structure, constituted by the double hull of a ship, and a waterproof and thermally insulating tank arranged in the supporting structure. The facility includes a dome structure that serves as a penetration point for a loading/unloading tower with conduits for loading or unloading the tank. The dome structure projects upward from an upper load-bearing wall. It has vertical load-bearing walls that rise above the ship's deck and a horizontal wall that is positioned on top of the vertical load-bearing walls. The horizontal wall supports a cover that has a metal cover wall and thermal insulation that is secured against the underside of the metal cover wall. Furthermore, the vertical load-bearing walls of the dome structure are covered with a multi-layer structure comprising, from the outside towards the inside, a secondary thermally insulating barrier, a secondary sealing membrane, a primary sealing membrane, a primary thermally insulating barrier and a primary waterproofing membrane. The primary sealing membrane has a plurality of waves to provide elasticity and which protrude towards the interior of the dome structure.

As described in relation to Figures 15 and 16 of the aforementioned document, after the metal cover wall has been attached and welded against the other walls of the dome structure then the loading/unloading tower has been fixed against said metal wall cover, insulating elements are fixed in a central portion of the cover. At this stage, a peripheral portion of the metal cover wall is not coated with insulating elements. In a subsequent step, edge insulating elements are positioned against the peripheral portion of the metal cover wall. However, the presence of the waves of the primary sealing membrane projecting inwards, in the upper part of the vertical walls of the dome structure hinders the positioning of the edge insulating elements, against the peripheral portion of the metal cover wall , in a space provided between the primary sealing membrane of one of the vertical dome walls and one of the insulating elements fixed in the central portion of the metal cover wall.

Summary

An idea underlying the invention is to propose a dome structure in which the installation of the insulation against the cover of the dome structure is facilitated.

According to one embodiment, the invention provides a dome structure for a sealed and thermally insulating tank, the dome structure comprising a plurality of dome side walls intended to project vertically from a ceiling wall of the tank and defining a passage intended to be crossed by at least one pipe intended for loading or unloading liquefied gas from the tank and a horizontal cover which closes the passage, the plurality of dome side walls comprising a first dome side wall comprising a membrane corrugated sealing, the corrugated sealing membrane comprising at least one wave which projects in the direction of the passage, the dome structure comprising at least one insulating block anchored against an underside of the cover, said insulating block and the wave being, in projection in a horizontal plane, spaced from each other by a first distance; an insulating gasket comprising one or more gasket elements, said insulating gasket being adjacent to the first side wall, placed against the cover and disposed between the insulating block and the first side wall, the or each gasket element having a thickness in one direction orthogonal to the first dome side wall which is less than the first distance or is capable of being compressed in the direction orthogonal to the first dome side wall which is less than the first distance, a retaining plate being anchored to a lower surface of the insulating block and extending under the insulating gasket.

Thanks to these characteristics, thermal insulation of the dome structure is complete, the insulating gasket making it possible to thermally insulate the surroundings of the corrugated waterproofing membrane. In addition, taking into account the aforementioned characteristics of the insulating gasket, it can be easily installed despite the presence of the wave of the waterproofing membrane.

According to embodiments, such a dome structure may include one or more of the following features.

According to one embodiment, the retaining plate is placed at a distance from the sealing membrane.

Thus, such a configuration avoids friction between the retaining plate and the corrugated sealing membrane, the friction resulting in premature wear of the retaining plate and the corrugated sealing membrane, and the friction being able to be aggravated under the the effect of thermal contraction phenomena and deformation of the supporting structure.

According to one embodiment, a distance between the retaining plate and the sealing membrane is between 5mm and 25mm.

According to a preferred embodiment, a distance between the retaining plate and the sealing membrane is between 10mm and 20mm.

More preferably, a target value of the distance between the retaining plate and the sealing membrane is 15mm.

Thus, such distance values make it possible to reduce the risk of friction of the retaining plate on the surface of the waterproofing membrane.

According to one embodiment, the holding plate is made of wood.

According to one embodiment, the holding plate has cutouts through which vertical waves pass.

According to a preferred embodiment, the holding plate is made of plywood.

Indeed, wood – and in particular plywood – is a material with a low thermal conductivity coefficient. In addition, in the event of accidental contact between the retaining plate and the sealing membrane, the wooden retaining plate is less likely to scratch the waterproofing membrane than if the retaining plate was made of another material (e.g. metallic example).

According to one embodiment, the at least one trim element is made of a material chosen from glass wool, rock wool and polyester wadding.

Thus, the trim element is made of a thermally insulating and flexible material.

In addition, such materials are compressible and therefore facilitate the insertion of the trim element(s).

According to one embodiment, the at least one insulating trim element is made of insulating polymer foam.

Thus, the trim element is composed of a thermally insulating material thus making it possible to thermally insulate the dome structure.

According to one embodiment, the corrugated sealing membrane comprises vertical waves and the insulating gasket comprises several gasket elements including a contact gasket element is placed against the sealing membrane between two successive vertical waves

According to one embodiment, the contact trim element has beveled ends.

Thus, the contact gasket element best matches the shape of the waves of the corrugated sealing membrane, which ensures optimal thermal insulation.

According to one embodiment, the contact trim element has a thickness in a direction normal to the dome side wall identical to a wave height.

According to one embodiment, the trim elements comprise a secondary trim element, the secondary trim element extending in a space between the contact trim element and the insulating block and having a dimension in a direction normal to a plane of symmetry of the vertical waves greater than a dimension of the contact lining element in said direction.

Thus, the number of steps for mounting the insulating gasket is reduced, because the secondary gasket element is common to several contact gasket elements.

According to one embodiment, the sealing membrane is, in a portion positioned above the retaining plate, covered with insulating trim elements.

Thus, the dome structure can be completely thermally insulated using the insulating pad.

According to one embodiment, the at least one insulating block is anchored to the cover by means of a threaded stud, the threaded stud passing through the at least one insulating block from side to side, a support plate being positioned against a lower face of the at least one insulating block, a nut being screwed onto the threaded stud and retaining the support plate.

Thus, such a characteristic allows easy fixing of the at least one insulating block.

According to one embodiment, the invention provides a waterproof and thermally insulating tank comprising a aforementioned dome structure.

According to one embodiment, the waterproof and thermally insulating tank comprises a loading/unloading tower comprising at least two vertical masts passing through the cover and fixed to each other by crosspieces, the two vertical masts each forming a tank loading or unloading conduit.

According to one embodiment, the invention provides a vessel for transporting a fluid, the vessel comprising a aforementioned waterproof and thermally insulating tank.

According to one embodiment, the invention provides a transfer system for a fluid, the system comprising a aforementioned vessel, insulated pipes arranged so as to connect the tank of the vessel to a floating or terrestrial storage installation and a pump for driving fluid through insulated pipelines from or to the floating or land-based storage facility to or from the vessel's tank.

Disposer une garniture isolante comportant un ou plusieurs éléments de garniture entre le bloc isolant et la première paroi latérale, le ou chaque élément de garniture présentant une épaisseur dans une direction orthogonale à la première paroi latérale de dôme qui est inférieure à la première distance ou étant comprimée dans la direction orthogonale à la première paroi latérale jusqu’à présenter une épaisseur dans une direction orthogonale à la première paroi latérale de dôme qui est inférieure à la première distance,
Ancrer une plaque de maintien à une surface inférieure du bloc isolant, la plaque de maintien s’étendant sous la garniture isolante de manière à la maintenir en place.

According to one embodiment, the invention provides a method of assembling a dome structure for a sealed and thermally insulating tank, said dome structure comprising a plurality of dome side walls intended to project vertically from a wall of ceiling of the tank and defining a passage intended to be crossed by at least one pipe intended for loading or unloading liquefied gas from the tank and a horizontal cover which closes the passage, the plurality of dome side walls comprising a first side wall dome comprising a corrugated sealing membrane, the corrugated sealing membrane comprising at least one wave which projects in the direction of the passage, the dome structure comprising at least one insulating block anchored against an underside of the cover, said insulating block and the wave being, in projection in a horizontal plane, spaced from each other by a first distance, the assembly process comprising the following steps:

Disposing an insulating trim comprising one or more trim elements between the insulating block and the first side wall, the or each trim element having a thickness in a direction orthogonal to the first dome side wall which is less than the first distance or being compressed in the direction orthogonal to the first side wall until it presents a thickness in a direction orthogonal to the first dome side wall which is less than the first distance,
Anchor a retaining plate to a lower surface of the insulating block, with the retaining plate extending below the insulating pad to hold it in place.

According to one embodiment, the assembly method is such that the at least one trim element is inserted vertically in a space between the corrugated sealing membrane and the insulating block, then is moved in a direction having a horizontal component so as to come into contact with the corrugated waterproofing membrane.

According to one embodiment, the assembly method is such that the at least one insulating block is previously fixed to the cover by means of a threaded stud, the threaded stud passing through the at least one insulating block from side to side, a support plate being positioned against an underside of the at least one insulating block, a nut being screwed onto the threaded stud and retaining the support plate.

According to one embodiment, the assembly method is such that trim elements cover a portion of the corrugated sealing membrane which is positioned above the retaining plate.

According to one embodiment, the method further comprises the following steps:
- arrange contact trim elements between each two successive vertical waves, the contact trim elements having a height identical to a wave height,
- arrange secondary trim elements occupying a gap between the contact trim elements and the at least one insulating block.

According to one embodiment, the secondary trim elements have a dimension in a direction normal to a plane of symmetry of the waves longer than a dimension of the contact trim elements in said direction.

According to one embodiment, the assembly process is such that the ends of the trim elements are previously beveled before being inserted into the space between the corrugated sealing membrane and the insulating block.

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

Brief description of the figures

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

There is a partial schematic view of a supporting structure intended to receive the walls of a waterproof and thermally insulating tank.

There is a schematic view of the multilayer structure of the tank walls.

There is a schematic view illustrating a loading/unloading tower and partially illustrating the supporting structure inside which it is mounted.

There is a schematic sectional view of a dome structure that can be used within the supporting structure of the .

There is a partial schematic representation of the dome structure during a preliminary insulation stage.

There is a partial schematic representation of the dome structure during a step of inserting an insulating gasket.

There is a partial schematic representation of the dome structure during a step of maintaining an insulating liner.

There is a partial schematic representation of the dome structure in a final state.

There is a schematic perspective representation during the preliminary isolation stage.

There is a schematic perspective representation after the preliminary isolation step.

There is a schematic perspective representation of a detail of the dome structure after mounting a contact trim element.

There is a schematic perspective representation of the detail of the dome structure portion after the assembly of a secondary trim element.

There is a schematic perspective representation of trim elements within the dome structure portion.

There is a side schematic representation of the trim elements within the dome structure portion.

There is a schematic perspective representation of the detail of the dome structure portion after mounting a retaining plate.

There is a schematic perspective representation of the dome structure portion in the final state.

There is a cut-away schematic representation of an LNG ship tank and a loading/unloading terminal for this tank.

There represents the rear part of a supporting structure 1 intended to receive the walls of a waterproof and thermally insulating tank. The supporting structure 1 is formed by the double hull of a ship. The supporting structure 1 has a general polyhedral shape. The supporting structure 1 has two front walls 2 and rear 3, here octagonal in shape. On the , the front wall 2 is only partially shown in order to allow visualization of the internal space of the supporting structure 1. The front walls 2 and rear walls 3 are cofferdam walls of the ship and extend transversely to the longitudinal direction of the ship. The supporting structure 1 also comprises an upper wall 4, a lower wall 5 and side walls 6, 7, 8, 9, 10, 11. The upper wall 4, the lower wall 5 and the side walls 6, 7, 8, 9, 10, 11 extend in the longitudinal direction of the ship and connect the front 2 and rear 3 walls.

The upper wall 4 comprises, near the rear wall 3 of the supporting structure 1, a space, of rectangular parallelepiped shape, projecting upwards, called liquid dome 12. The liquid dome 12 is defined by two transverse walls, front 13 and rear 14, and by two side walls 15, 16 which extend vertically and project upwards from the upper wall 4. The liquid dome 12 further comprises a horizontal cover, not shown on the , which is intended to cover in a watertight manner the opening provided between the front 13, rear 14 and side walls 15, 16 of the liquid dome 12.

In reference to the , the tank whose assembly process will be described subsequently is a membrane tank having a multilayer structure. Also, as shown schematically on the , each wall of the tank successively presents, from the outside towards the inside, in the direction of thickness of the wall, a secondary thermally insulating barrier 44 comprising insulating elements resting against the supporting structure 1, a sealing membrane secondary 18 anchored to the insulating elements of the thermally insulating barrier 44, a primary thermally insulating barrier 19 comprising insulating elements resting against the secondary sealing membrane 18 and a primary sealing membrane 20 anchored to the insulating elements of the primary thermally insulating barrier 19 and intended to be in contact with the fluid contained in the tank. This multilayer structure of the tank is arranged on each of the walls 4, 5, 6, 7, 8, 9, 10, 11 of the supporting structure 1. This multilayer structure is also present on the walls of the liquid dome 12, except at the level of the cover.

For example, each wall of the tank can in particular be of the Mark III type, as described for example in FR2691520, or of the Mark V type as described for example in WO14057221.

Each wall of the tank is anchored to the respective wall of the supporting structure 1, proceeding from the outside towards the inside of the tank, that is to say:
- by anchoring the insulating elements of the secondary thermally insulating barrier 44 on the respective wall of the supporting structure 1;
- by anchoring the secondary sealing membrane 18 on the insulating elements of the secondary thermally insulating barrier 44;
- by anchoring the insulating elements of the primary thermally insulating barrier 19 on the insulating elements of the secondary thermally insulating barrier 44 or on the supporting structure 1 through the secondary sealing membrane 18; Then
- by anchoring the primary sealing membrane 20 on the insulating elements of the primary thermally insulating barrier 19.

Furthermore, the tank includes a loading/unloading tower, illustrated in Figures 3 and 4, allowing in particular to load the cargo into the tank before its transport and/or to unload the cargo after its transport. The loading/unloading tower 21 is installed in the vicinity of the rear wall 3 of the supporting structure 1, because when unloading the cargo, the ship leans backwards, which makes it possible to optimize the quantity of cargo likely to be loaded. be unloaded by the loading/unloading tower 21.

The loading/unloading tower 21 is suspended from the upper wall 4 of the supporting structure 1 and more particularly from the cover of the liquid dome 12. The loading/unloading tower 21 extends over substantially the entire height of the tank. The loading/unloading tower 21 supports, at its lower end, one or more cargo unloading pumps.

We observe that the loading/unloading tower 21 comprises a tripod structure, that is to say that it comprises three vertical masts 22, 23, 24 which are each fixed to each other by crosspieces 25. Each of the masts 22, 23, 24 is hollow and passes through the cover of the liquid dome 12. Each of the masts 22, 23, 24 thus forms either a loading and/or unloading line allowing fluid to be loaded or unloaded to or from the tank; or an emergency well allowing the descent of an emergency pump and an unloading line in the event of failure of the other unloading pumps. In one embodiment shown, two of the masts 22, 23 form a tank unloading line and are, to do this, each associated with an unloading pump 26, 27 fixed to the lower end of the loading tower/ unloading 21 while the third mast 24 forms an emergency well. In such an embodiment, the loading/unloading tower 21 carries one or more loading lines, not shown, which do not constitute one of the masts 22, 23, 24 of the tripod structure.

With reference to Figures 5 to 8, the method of mounting the insulation against the cover 17 of the dome structure 12 will be described.

In a first step represented schematically on the , the dome structure 12 is in a preliminary state in which a central insulating block 30 is anchored to the cover 17. The side wall 15 is covered with a sealing membrane 32. A fastener 36 is secured to the cover 17 and is placed vertically.

The first step consists of placing an end insulating block 31 between the central insulating block 30 and the sealing membrane 32. The end insulating block 31 is dimensioned so as to be able to be inserted vertically between the central insulating block 30 and the sealing membrane 32 without coming into contact with a wave 33, the wave 33 developing in a direction normal to a plane of the .

The end insulating block 31 is anchored to the cover by means of the clip 36, the clip 36 intended to pass through the end insulating block 31 from one side to the other.

The end insulating block 31 and the central insulating block 30 can be composed of insulating polymer foam, for example polyurethane, with a lower thickness composed of wood, preferably plywood.

In reference to the , after the first assembly step, the end insulating block 31 is crossed by the clip 36 and protrudes from a lower surface of the end insulating block 31. The clip 36 is preferably placed in the center of the insulating block end 31.

The end insulating block 31 is placed against the central insulating block 30, leaving a gap 34 between the end insulating block 31 and the sealing membrane 32. In addition, a height of the end insulating block 31 in a direction normal to the cover 17 is identical to a height of the central insulating block 30. As illustrated in this , the end insulating block 31 and the wave 33, which has the greatest height, are, in projection in a horizontal plane, spaced from each other by a first dimension which corresponds to the reference d1 on the .

With reference to Figures 6 and 7, a second assembly step is shown. The second assembly step consists of inserting an insulating gasket 40 between the end insulating block 31 and the sealing membrane 32, the insulating gasket 40 being inserted through the gap 34. The insulating gasket 40 is inserted so as to completely occupy the gap 34.

In one embodiment, the insulating lining 30 comprises a lining element which has a dimension d2 in the direction orthogonal to the side wall 15 which is greater than the dimension d1. In this case, the insulating pad 40 is composed of a compressible material, the insulating pad 40 then being compressed so as to be able to occupy the entire gap 34.

In an alternative embodiment, the insulating lining 40 can also be composed of several lining elements, each lining element then having a dimension d2 in the free or compressed state which is less than d1. The trim elements can thus be inserted sequentially and then juxtaposed in the gap.

In this case, the trim elements are inserted vertically into the gap then are moved horizontally until they are in contact with the sealing membrane 32 or with a previous trim element previously placed against the sealing membrane 32. trim elements can be compressed to pass through the gap, although this is not obligatory if they have a dimension d2 less than d1.

The insulating pad 40 is made up of insulating elements such as glass wool, rock wool, polyester wadding or flexible foam. The insulating pad 40 may also comprise polymer foam, for example polyurethane.

It is also possible to combine different types of materials and to have heterogeneous trim elements, composed two by two of different elements.

With reference to Figures 7 and 8, a third assembly step consists of placing a retaining plate 35 under the insulating gasket 40 so as to hold it in place. The holding plate 35 is made of wood, preferably plywood.

The retaining plate 35 is placed so as to partially overlap a lower surface of the end insulating block 31 and is anchored to said lower surface. The retaining plate 35 extends under the insulating gasket 40 and up to the sealing membrane 32 (without, however, being in direct contact with said sealing membrane 32), so as to prevent escape of the insulating gasket 40 .

The retaining plate 35 can be fixed to the end insulating block by gluing or by means of screws, for example.

With reference to Figures 9 to 11, a portion of the dome structure 12 is shown in perspective, in the preliminary state. The cover 17 is equipped with fasteners 36, such as studs, regularly distributed.

The central insulating block 30 is intended to be brought into contact with the cover 17 and fixed to it, for example by gluing or by means of anchoring devices not shown.

A first side wall 15 is covered by a first sealing membrane 321. A second side wall 16 is covered by a second sealing membrane 322.

The first sealing membrane 321 and the second sealing membrane 322 comprise horizontal waves 33, developing parallel to a plane of the cover 17.

The first sealing membrane 321 and the second sealing membrane 322 further comprise vertical waves 39 perpendicular to the horizontal waves 33 and parallel to a direction normal to the plane of the cover 17.

In reference to the , a first end insulating block 311 is placed between the central insulating block 30 and the first sealing membrane 321. A second end insulating block 312 is placed between the central insulating block 30 and the second sealing membrane 322 .

The first insulating end block 311 and the second insulating end block 312 are however not directly in contact with respectively the first sealing membrane 321 and the second sealing membrane 322.

The first insulating end block 311 and the second insulating end block 321 are fixed to the cover by fasteners 36, here studs. The fasteners 36 form a mesh of the cover wall 17 and are placed equidistant from each other. The clips 36 protrude from the surface of the cover wall 17. The clips 36 pass right through the end insulating blocks 311, 321 and are held in place at a lower surface of the insulating blocks. To do this, for example, support plates are mounted on one end of the clips 36, positioned against the underside of the insulating blocks and held in place by bolts.

With reference to Figures 11 to 15, an arrangement of trim elements between the end insulating block 31 and the sealing membrane 32 is explained according to one embodiment. In the aforementioned figures, a detail of a corner zone of the dome structure 12 is shown in perspective.

In reference to the , a first contact lining element 41 is inserted into the gap 34 then placed against the sealing membrane 32. The first contact lining element 41 has a height in a direction normal to the plane of the cover 17 such that the first contact trim element 41 occupies a space between the cover 17 and the horizontal end wave 331, the horizontal end wave 331 being the horizontal wave closest to the cover 17.

The first contact pad element 41 also has a dimension such that it can be housed between two successive vertical waves 39 or, alternatively, between one end of the dome structure 12 and a first vertical wave 39.

Finally, a thickness of the first contact lining element 41 in a direction normal to the first side wall 15 is identical, or substantially identical, to a height of the wave 33. However, according to other embodiments, the contact lining element 41 can have a greater thickness and occupy the entire gap 34, in particular in the case where the contact lining element 41 is composed of a compressible material.

In reference to the , a secondary lining element 42 is inserted between the contact lining element 41 and the end insulating block 31. The secondary lining element 42 has a length greater than the length of the contact lining element 41. In fact, the secondary trim element 42 is not limited in length by the presence of vertical waves 39, unlike the contact trim element 41.

With reference to Figures 13 and 14, a contact lining element 41 is placed between each two horizontal waves 33 which follow one another. In addition, the secondary lining element 42, having a greater length than the contact lining element 41, may be common to several successive contact lining elements 41. According to a preferred embodiment, the contact trim elements 41 have beveled sides 43 at an inclination such that the contact trim elements 41 are tangent to the waves of the sealing membrane 32, the horizontal wave 33 having two curved sides.

The second trim element 42 is placed against the contact trim elements 41 and is tangent with a peak of the horizontal wave 33.

In reference to the , we observe that the trim elements can have different thicknesses in each dimension of the dome structure 12. In fact, when the sealing membrane has waves having different heights, the highest waves are those oriented according to the longitudinal direction of the ship while the smaller ones are oriented in the transverse direction of the ship. This is the reason why depending on the orientation of the side wall of the dome structure, the vertical waves 33 of the sealing membrane 32 can be the largest on a side wall (when the latter is oriented transversely) and the smaller ones on an adjacent side wall (when oriented longitudinally). We observe on the that the retaining plate 35 is not in contact with the sealing membrane 32. In fact, a distance between the sealing membrane 32 and the retaining plate 35 is between 5mm and 25mm. The presence of such clearance makes it possible to avoid contact between the sealing membrane 32 and the retaining plate 35, even when the tank is subjected to significant thermal deformations during its use. Also, the holding plate 35 also includes cutouts through which the vertical waves pass.

The adjustment is carried out at the end insulating block 31. Indeed, depending on the margin which we wish to have, we can anchor the retaining plate 35 more or less close to the sealing membrane 32. The retaining plate 35 can be fixed with screws or by gluing.

In reference to the , a more comprehensive view of the corner area of the dome structure is shown. The trim elements border the ends of the insulating blocks 31 facing the sealing membrane 32.

According to one embodiment shown here, each trim element of the insulating trim 40 occupies an entire area delimited by the sealing membrane 32, the end insulating block 31 and two successive vertical waves 39.

The liquefied gas intended to be stored in the tank may in particular be liquefied natural gas (LNG), that is to say a gas mixture comprising mainly methane as well as one or more other hydrocarbons. The liquefied gas can also be hydrogen, ethane or liquefied petroleum gas (LPG), that is to say a mixture of hydrocarbons resulting from petroleum refining essentially comprising propane and butane.

In reference to the , a cutaway view of an LNG ship 70 shows a watertight 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 waterproof barrier intended to be in contact with the LNG contained in the tank, a secondary waterproof barrier arranged between the primary waterproof barrier and the double hull 72 of the ship, and two insulating barriers arranged respectively between the primary waterproof barrier and the secondary waterproof barrier and between the secondary waterproof barrier and the double hull 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 appropriate connectors, to a maritime or port terminal to transfer a cargo of LNG from or to the tank 71.

There represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipeline 76 and an onshore installation 77. The loading and unloading station 75 is a fixed off-shore installation comprising a movable arm 74 and a tower 78 which supports the mobile arm 74. The mobile arm 74 carries a bundle of insulated flexible pipes 79 which can connect to the loading/unloading pipes 73. The adjustable mobile arm 74 adapts to all LNG carrier templates. A connection pipe not shown extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG tanker 70 from or to the onshore installation 77. This includes 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 onshore installation 77 over a long distance, for example 5 km, which makes it possible to keep the LNG ship 70 at a long 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 on-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 quite obvious that it is in no way limited and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

The use of the verb “include”, “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 parenthetical reference sign shall not be construed as a limitation of the claim.

Claims

A dome structure (12) for a sealed and thermally insulating tank, the dome structure having a plurality of dome side walls (13, 14, 15, 16) intended to project vertically from a ceiling wall of the tank and defining a passage intended to be crossed by at least one pipe (21) intended for loading or unloading liquefied gas from the tank and a horizontal cover (17) which closes the passage,
the plurality of dome side walls comprising a first dome side wall comprising a corrugated sealing membrane (32), the corrugated sealing membrane comprising at least one wave (33) which projects in the direction of the passage,
the dome structure (12) comprising at least one insulating block (31) anchored against a lower face of the cover, said insulating block and the wave (33) being, in projection in a horizontal plane, spaced one from the another from a first distance;
an insulating lining comprising one or more lining elements (40, 41, 42), said insulating lining being adjacent to the first side wall (15), placed against the cover (17) and disposed between the insulating block and the first side wall ,
the or each trim element (40, 41, 42) having a thickness in a direction orthogonal to the first side wall of the dome which is less than the first distance or is capable of being compressed in the direction orthogonal to the first side wall of dome which is less than the first distance,
a retaining plate (35) being anchored to a lower surface of the insulating block and extending below the insulating pad.
Dome structure (12) according to claim 1, wherein the retaining plate (35) is placed at a distance from the sealing membrane (32).
Dome structure (12) according to claim 2, wherein a distance between the retaining plate (35) and the sealing membrane (32) is between 5mm and 25mm.
Dome structure (12) according to one of the preceding claims, in which the retaining plate (35) is made of wood.
Dome structure (12) according to one of the preceding claims, in which the at least one insulating lining element (40, 41, 42) is made of a material chosen from glass wool, rock wool and polyester wadding.
Dome structure (12) according to one of claims 1 to 4, in which the at least one insulating trim element (40, 41, 42) is made of insulating polymer foam.
Dome structure (12) according to one of the preceding claims, in which the corrugated sealing membrane (32) comprises vertical waves and in which the insulating lining comprises several lining elements (40, 41, 42) including one element contact pad (41) is placed against the sealing membrane between two successive vertical waves.
A dome structure (12) according to claims 6 and 7 taken in combination, wherein the contact trim member (41) has beveled ends (43).
A dome structure (12) according to claim 7 or 8, wherein the contact pad member (41) has a thickness in a direction normal to the dome side wall the same as a wave height.
A dome structure (12) according to claim 9, wherein said trim members (40, 41, 42) include a secondary trim member (42), the secondary trim member extending into a space between the member contact pad (41) and the insulating block (31) and having a dimension in a direction normal to a plane of symmetry of the vertical waves greater than a dimension of the contact pad element (41) in said direction .
Dome structure (12) according to one of the preceding claims, in which the sealing membrane (32) is, in a portion provided above the retaining plate (35), covered with insulating trim elements.
Dome structure (12) according to one of the preceding claims, in which the at least one insulating block is anchored to the cover by means of a threaded stud, the threaded stud passing through the at least one insulating block from side to side , a support plate being positioned against an underside of the at least one insulating block, a nut being screwed onto the threaded stud and retaining the support plate.
Waterproof and thermally insulating tank comprising a dome structure (12) according to any one of claims 1 to 12.
Waterproof and thermally insulating tank according to claim 13, comprising a loading/unloading tower (21) comprising at least two vertical masts passing through the cover and fixed to one another by crosspieces, the two vertical masts each forming a loading or unloading conduit from the tank.
Vessel for transporting a fluid, the vessel comprising a watertight and thermally insulating tank according to claim 13 or 14.
A transfer system for a fluid, the system comprising a vessel as claimed in claim 15, insulated pipes arranged to connect the vessel vessel to a floating or land-based storage facility and a pump for driving a fluid through the insulated pipes from or to the floating or land-based storage facility to or from the ship's tank.
A method of assembling a dome structure (12) for a sealed and thermally insulating tank, said dome structure having a plurality of dome side walls intended to project vertically from a ceiling wall of the tank and defining a passage intended to be crossed by at least one pipe intended for loading or unloading liquefied gas from the tank and a horizontal cover which closes the passage, the plurality of dome side walls (13, 14, 15, 16) comprising a first wall side dome (15) comprising a corrugated sealing membrane (32), the corrugated sealing membrane comprising at least one wave (33) which projects in the direction of the passage, the dome structure comprising at least one insulating block ( 31) anchored against a lower face of the cover (17), said insulating block (31) and the wave (33) being, in projection in a horizontal plane, spaced from each other by a first distance, the assembly process comprising the following steps:
- arrange an insulating lining comprising one or more lining elements (40, 41, 42) between the insulating block (31) and the first side wall (15), the or each lining element having a thickness in a direction orthogonal to the dome side wall which is less than the first distance or being compressed in the direction orthogonal to the first side wall until it has a thickness in a direction orthogonal to the first dome side wall which is less than the first distance,
- anchor a retaining plate (35) to a lower surface of the insulating block, the retaining plate extending under the insulating pad so as to hold it in place.
Assembly method according to the preceding claim, in which the at least one trim element (40, 41, 42) is inserted vertically in a space between the corrugated sealing membrane (32) and the insulating block (31), then is moved so as to come into contact with the corrugated sealing membrane (32).
Assembly method according to claim 17 or 18, in which the at least one insulating block (31) is previously fixed to the cover (17) by means of a threaded stud (36), the threaded stud passing through the at least an insulating block (31) from side to side, a support plate being positioned against an underside of the at least one insulating block, a nut being screwed onto the threaded stud and retaining the support plate.
Assembly method according to one of claims 17 to 19, in which trim elements (40, 41, 42) cover the corrugated sealing membrane (32).
Assembly method according to the preceding claim, in which the insulating lining comprises several lining elements (40, 41, 42) including a contact lining element (41) and a secondary lining element (42), the step of arrangement of the insulating gasket comprising:

- arrange the contact trim element (41) between two successive vertical waves, the contact trim element having a height identical to a wave height,
- arrange the secondary trim element in a gap (34) between the contact trim element (41) and the at least one insulating block (31), the secondary trim element having a dimension in a normal direction to a plane of symmetry of the waves longer than a dimension of the contact lining elements in said direction.
Assembly method according to the preceding claim, in which the contact trim element (41) has ends (43), previously beveled before being inserted into the space between the corrugated sealing membrane (32) and the insulating block (31).
A method of loading or unloading a ship according to claim 15, wherein a fluid is conveyed through insulated pipes from or to a floating or land-based storage facility to or from the ship's tank.