WO2022253615A1

WO2022253615A1 - Installation for storing a liquefied gas

Info

Publication number: WO2022253615A1
Application number: PCT/EP2022/063906
Authority: WO
Inventors: Emmanuel HIVERT; Guillaume GOUBARD; Erwan MICHAUT
Original assignee: Gaztransport Et Technigaz
Priority date: 2021-05-31
Filing date: 2022-05-23
Publication date: 2022-12-08
Also published as: FR3123409A1; CN117597536A; KR20240017362A; TW202336379A; EP4348097A1; FR3123409B1

Abstract

The invention relates to an installation for storing a liquefied gas, comprising a bearing structure (1) and a sealed and thermally insulating tank arranged in the bearing structure (1), the bearing structure (1) comprising a dome structure (19) projecting vertically towards the outside of the tank from an upper bearing wall (3), the dome structure (19) having vertical dome walls (22) projecting upwardly from the upper bearing wall (3) and each having an upper end, the dome structure (19) having a seat wall (23) developing horizontally and having a peripheral edge region (33), the dome structure (19) having a cover (25) which covers the passage and is welded in a sealed manner to the seat wall (23), the cover (25) being welded to at least one intermediate plate (34), the intermediate plate (34) being welded to the seat wall (23) in the peripheral edge region (33).

Description

Liquefied gas storage facility

The invention relates to the field of storage facilities for liquefied gas comprising a sealed and thermally insulating tank arranged in a supporting structure.

In particular, the invention relates to the field of sealed and thermally insulating tanks for the storage and/or transport of liquefied gas at low temperature, such as tanks for the transport of Liquefied Petroleum Gas (also called LPG) having for example a temperature between -50°C and 0°C, or for the transport of Liquefied Natural Gas (LNG) at approximately -162°C. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank may be intended for the transport of liquefied gas or to receive liquefied gas used as fuel for the propulsion of the floating structure.

The invention relates more particularly to a storage facility of the aforementioned type comprising a dome structure projecting upwards from an upper load-bearing wall of the load-bearing structure and intended to be traversed by at least one pipe intended for loading or unloading the tank.

Technology background

The document WO2015155377 discloses a storage facility for a liquefied gas comprising a support structure, consisting of the double hull of a ship, and a sealed and thermally insulating tank arranged in the support structure. The installation has a dome structure, shown in the of the aforementioned document, which serves as a point of penetration for various equipment of the tank, such as pipes intended for loading or unloading the tank. The dome structure projects upward from an upper supporting wall. It has a vertical load-bearing wall that rises above the ship's deck and a horizontal wall that is positioned atop the vertical load-bearing wall. The horizontal wall supports a cover which consists essentially of a metal cover wall and thermal insulation which fits into the top of the dome structure.

In order to fix the horizontal wall of the dome structure and the metal cover wall and ensure the tightness of the dome structure, it is known to make a line of welds along the peripheral edge of the metal cover wall. When the pressure inside the tank is greater than atmospheric pressure, this pressure differential exerts on the lid a force directed towards the outside of the tank which flexes the metal wall of the lid. Such stresses are likely to degrade the aforementioned welding line and thus lead to sealing problems of the dome structure, in particular when the tank is intended to store gas at pressures higher than those of traditional membrane tanks.

Such a dome structure arrangement is therefore not fully satisfactory.

Summary

One idea underlying the invention is therefore to propose a liquefied gas storage facility comprising a dome structure which has better pressure resistance.

To do this, according to one embodiment, the invention provides a storage facility for a liquefied gas comprising a supporting structure and a sealed and thermally insulating tank arranged in the supporting structure, the supporting structure comprising an upper supporting wall and the tank comprising a ceiling wall fixed to the upper load-bearing wall, the upper load-bearing wall and the ceiling wall being interrupted locally so as to delimit an opening, the load-bearing structure comprising a dome structure projecting towards the outside of the tank from the upper load-bearing wall around the opening and defining a passage intended to be traversed by at least one pipe intended for loading or unloading liquefied gas from the tank, the dome structure comprising dome walls projecting from the load-bearing wall upper and each having an upper end, the dome structure having a seat wall fi attached to the upper ends of the vertical dome walls, the seat wall extending horizontally and having a peripheral rim area which borders the passage and which projects towards the passage from the vertical dome walls, the dome structure comprising a lid which covers the passage and is sealingly welded to the seat wall, said cover being welded to at least one intermediate plate, said intermediate plate being welded to the seat wall in the peripheral edge zone.

Thus, the cover being welded to the peripheral edge zone which is the zone of the seat wall closest to the center of the dome structure, the moment being exerted on said welds when the pressure in the vessel is greater than the pressure outside the tank, is reduced, which makes it possible to limit the bending of the lid and to improve the resistance to pressure of the welds securing the lid to the seat wall. In addition, the use of an intermediate plate makes it possible to distribute the forces over a greater number of welds. In addition, the intermediate plate constitutes an additional stiffness between the cover and the seat wall which is capable of absorbing part of the forces by deforming.

According to embodiments, such an installation may comprise one or more of the following characteristics.

According to one embodiment, the intermediate plate is welded to the peripheral edge zone along an internal edge of the peripheral edge zone. This allows the intermediate plate to be fixed to the seat wall by means of a lap line weld which is simple to implement and ensures satisfactory fixing performance.

According to one embodiment, the cover is welded to a plurality of intermediate plates which are arranged around the passage and which are each welded to the seat wall in the peripheral edge zone, preferably along the internal edge of the seat zone. peripheral border.

According to one embodiment, the or each intermediate plate protrudes inward from the dome structure. Thus, the intermediate plate extends towards the passage beyond the inner edge of the peripheral border zone.

According to one embodiment, the intermediate plate is welded to the lid by means of at least one line of welding, continuous or discontinuous, extending along at least one edge of the intermediate plate.

According to one embodiment, the intermediate plate is welded to the lid via at least two weld lines extending respectively along at least two edges of the intermediate plate arranged on either side of the edge internal of the peripheral border area. This makes it possible to distribute the forces over larger weld surfaces and to fix the intermediate plate to the cover by means of lap weld lines which are simple to implement and ensure satisfactory fixing performance.

According to one embodiment, the cover is welded in leaktight manner to the seat wall via an intermediate frame which is arranged around the passage and around the at least one intermediate plate.

According to one embodiment, the intermediate frame is welded to the seat wall by means of at least one tight welding line extending along an internal or external peripheral edge of the intermediate frame. According to one embodiment, said sealed weld line is a continuous weld line.

According to one embodiment, the cover is welded to the intermediate frame by means of at least one tight welding line. The at least one sealed weld line preferably extends along an outer peripheral edge of the cover. Thus, the lines of welds providing the seal between the cover and the seat wall are arranged outside the additional fastening zone of the cover to the seat wall so that they are only slightly stressed by the forces generated by the overpressure prevailing inside the tank. According to one embodiment, said sealed weld line is a continuous weld line.

According to one embodiment, the intermediate frame is welded to the seat wall via two weld lines extending respectively along the inner peripheral edge of the intermediate frame and along the outer peripheral edge of the intermediate frame. According to a first variant embodiment, the weld line extending along the outer peripheral edge of the intermediate frame is continuous and sealed, while the weld line extending along the inner peripheral edge of the intermediate frame is discontinuous. According to a second variant embodiment, the weld line extending along the inner peripheral edge of the intermediate frame is continuous and sealed, while the weld line extending along the outer peripheral edge of the intermediate frame is discontinuous. Finally, according to a third variant embodiment, the two weld lines are sealed, which further enhances the reliability of the seal.

According to one embodiment, the vessel comprises a vessel wall anchored against each of the dome walls, each vessel wall comprising a primary sealing membrane intended to be in contact with the liquefied gas contained in the vessel, the dome structure comprising a profiled frame against which the primary waterproofing membrane is welded, the profiled frame being welded by a tight welding line to the peripheral edge zone of the seat wall. Thus, under the effect of its thermal contraction, the primary sealing membrane exerts, on the peripheral edge zone of the seat wall, a force directed in a direction opposite to the forces which are exerted on said peripheral edge zone. due to the pressure exerted on the lid by the vapor phase of the liquefied gas, which makes it possible to further limit the bending of the seat wall and the lid.

In addition, the intermediate plate and the peripheral border area create a heat conduction area from the cover to the profiled frame which makes it possible to limit the temperature drop of the profiled frame and, consequently, to limit the thermal stresses acting on the profiled frame. .

According to one embodiment, the profiled frame has an L-shaped section which comprises a first wing and a second wing perpendicular to each other, the first wing being welded to the primary sealing membrane and to the area peripheral and vertically extending edging and the second horizontally extending wing being attached to a fixing lug which protrudes, towards the ceiling wall, i.e. downwards, from the edging area peripheral of the seat wall.

According to one embodiment, the profiled frame comprises reinforcing gussets which each have a first edge bearing against the first wing and a second edge bearing against the second wing.

According to one embodiment, the installation comprises a loading/unloading tower passing through the passage defined by the dome structure, the loading/unloading tower comprising at least two vertical masts passing through the cover and fixed to one to the other by crosspieces, the two vertical masts each forming a pipe for loading or unloading the tank.

According to one embodiment, the ceiling wall as well as each tank wall anchored against one of the dome walls comprises a secondary thermally insulating barrier retained against the load-bearing structure, a secondary sealing membrane resting against the secondary thermally insulating barrier , a primary thermally insulating barrier resting against the secondary sealing membrane and a primary sealing membrane which rests against the primary thermally insulating barrier and which is intended to be in contact with the liquefied gas contained in the tank.

A tank according to one of the aforementioned embodiments can be part of an onshore storage installation, for example for storing LNG or be installed in a floating, coastal or deep-water structure, in particular an LNG or LNG carrier, a floating storage and regasification unit (FSRU), floating production and remote storage unit (FPSO) and others. In the case of a floating structure, the tank may be intended to receive liquefied natural gas serving as fuel for the propulsion of the floating structure.

According to one embodiment, the invention relates to a vessel for transporting a fluid which comprises an installation of the aforementioned type.

According to one embodiment, the ship comprises a double hull which forms the load-bearing structure.

According to one embodiment, the invention also provides a transfer system for a fluid, the system comprising the 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 cause a flow of fluid through the insulated pipes from or to the floating or onshore storage facility to or from the vessel's tank.

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

Brief description of 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 accompanying drawings.

The is a schematic perspective view of a support structure intended to support a sealed and thermally insulating tank for storing a liquefied gas.

The is a schematic view of the multi-layered structure of the vessel walls.

The is a schematic sectional view illustrating the dome structure.

The is a partial sectional view illustrating the attachment of the dome structure cover to the seat wall.

The is a perspective view from below illustrating the dome structure.

The is a detailed view of the area of the illustrating an intermediate piece securing the cover to the seat walls.

] The is a top perspective view of the dome structure.

The is a partial representation in perspective of a profiled frame forming a stopping zone of the primary waterproofing membrane.

The is a partial representation in perspective of a profiled frame according to an alternative embodiment of the .

The is a cutaway schematic representation of an LNG tank and a loading/unloading terminal for this tank.

In relation to the , a support structure 1 is described against which a sealed and thermally insulating tank for storing a liquefied gas is intended to be fixed. The supporting structure 1 is, for example, formed by the double hull of a ship. The carrier structure 1 has a generally polyhedral shape. It has two front and rear load-bearing walls 2, here of octagonal shape, of which only the rear load-bearing wall is represented on the . The front and rear walls 2 are, for example, cofferdam walls of the ship which extend transversely to the longitudinal direction of the ship. The load-bearing structure 1 also comprises an upper load-bearing wall 3, a lower load-bearing wall 4 and side load-

bearing walls

5, 6, 7, 8, 9, 10.

The sealed and thermally insulating liquefied gas storage tank comprises a plurality of tank walls which are each anchored against one of the bearing

walls

2, 3, 5, 6, 7, 8, 9, 10 of the bearing structure 1.

As shown on the , each wall of the tank has successively, from the outside inwards, in the thickness direction of the wall, a secondary thermally insulating barrier 12 comprising insulating elements 13 fixed to the support structure 1, a membrane of secondary sealing 14 anchored to the insulating elements 13 of the secondary thermally insulating barrier 12, a primary thermally insulating barrier 15 comprising insulating elements 16 fixed to the insulating elements 13 of the secondary thermally insulating barrier 12 or to the supporting structure 1 and resting against the membrane secondary sealing 14 and a primary sealing membrane 17 anchored to the insulating elements 16 of the primary thermally insulating barrier 15 and intended to be in contact with the liquefied gas contained in the tank.

As shown in Figures 3 and 7, the upper load-bearing wall 3 as well as the ceiling wall 11 are locally interrupted so as to delimit an opening 18. The load-bearing structure 1 comprises a dome structure 19 which projects upwards from the upper bearing wall 3 around opening 18 and which defines a passage 24 intended to be traversed by one or

more pipes

20, 21, 47 intended for loading or unloading the tank.

Dome structure 19 has vertical dome walls 22. The dome walls 22 are, for example, four in number when the dome structure 19 has a square or rectangular section. The dome walls 22 project upwards from the upper load-bearing wall 3 and here rise above the ship's deck. The dome structure 19 also comprises, at the top of the dome walls 22, a seat wall 23 which extends horizontally all around the passage 24 formed by the dome walls 22 and thus forms with the dome walls 22, a coaming . The seat wall 23 supports a cover 25 through which passes the pipe(s) 20, 21 intended for loading or unloading the tank. Cover 25 includes a metal cover plate and thermal insulation, not shown, which is fixed against the underside of the metal cover plate and which fits into the dome structure 19. As illustrated in Figures 3 and 7 , according to one embodiment, the cover 25 comprises a network of stiffeners 48 which are each formed by metal plates welded against the upper face of the metal cover plate.

Furthermore, the load-bearing structure also comprises stiffeners 49 which are fixed under the seat wall 23 and rest against the upper load-bearing wall 3 and against the dome walls 22.

The multilayer structure of the tank, described above in relation to the , is also present against the dome walls 22 but is not present at the lid of the dome structure 19.

In the embodiment shown in the , a loading/unloading tower 26 passes inside the passage 24 defined by the dome structure 19. The loading/unloading tower 26 comprises three

vertical masts

20, 21, two of which are shown in the , which are each fixed to each other by crosspieces 27. The three

vertical masts

20, 21 pass through the cover 25 of the dome structure 19 and extend over substantially the entire height of the tank. The loading/unloading tower 26 comprises a base, not shown, which cooperates with a support foot which is fixed to the lower bearing wall 4 and which thus aims to ensure that the loading/unloading tower 26 is maintained in the vertical position.

According to one embodiment, each of the

masts

20, 21 is hollow, passes through the cover of the dome structure 19 and forms:
- a pipe which is intended for loading the tank with liquefied gas,
- a pipe which is intended for the unloading of liquefied gas from the tank and which is for this purpose associated with an unloading pump fixed to the lower end of the said pipe, or
- an emergency well allowing the descent of an emergency pump and an unloading line in the event of failure of an unloading pump.

In relation to the , the fixing of the lid 25, and more particularly of its metal plate, to the seat wall 23 is described below, as well as the structure, at their top, of the tank walls which are fixed to the dome walls 22.

The cover 25 is fixed in a sealed manner to the seat wall 23. To do this, the cover 25 is welded in a sealed manner to an intermediate frame 28, metallic, which is itself previously welded in a sealed manner to the seat wall. 23. Advantageously, the intermediate frame 28 is welded, in a sealed manner, to the seat wall 23 by means of two continuous weld lines 29, 30 with lap which respectively extend along the internal peripheral edge of the intermediate frame 28 and along the outer peripheral edge of the intermediate frame 28. Furthermore, the peripheral edge 39 of the cover 25 rests against the upper face of the intermediate frame 28 and is welded, in a sealed manner, by means of a weld line continuous 31 with lap, on said upper face of the intermediate frame 28. In the embodiment shown, the intermediate frame 28 rests at least partly against an outer zone 32 of the seat wall 23, that is to say a e zone which is positioned, with respect to the passage 24, outside the dome walls 22.

Further, the seat wall 23 has a peripheral rim area 33 which borders the passage 24 and which projects horizontally towards the passage 24 with respect to the dome walls 22. Additionally, the cover 25 is also attached to the seat wall. seat 23 by means of a plurality of intermediate plates 34, made of metal, represented in FIGS. 4, 5 and 6. The intermediate plates 34 are regularly arranged along the peripheral edge zone 33 and from the inside of the dome structure 19, with respect to the internal edge 37 of the peripheral edge zone 33. According to the embodiment shown in FIGS. 5 and 6, the intermediate plates 34 have an elongated shape along the edge internal 37 of the peripheral edge zone 33 and an L-shaped square at the angle between two adjacent dome walls 22.

Each of the intermediate plates 34 is previously welded to the cover 25 before being welded to the peripheral edge zone 33 of the seat wall 23. In the embodiment shown in the , the intermediate plates 34 are each lap-welded against the inner face of the cover 25, by at least two

weld lines

35, 36. The two

weld lines

35, 36 are formed along two edges of the intermediate plate 34 which are arranged on either side of the internal edge 37 of the peripheral edge zone 33. According to a variant embodiment, the intermediate plates 34 are welded on each of their edges against the internal face of the cover 25.

Furthermore, the seat wall 23 and each intermediate plate 34 are fixed to each other by means of a weld line 38, with lap, made along the internal edge 37 of the peripheral edge zone. 33 and against the underside of each intermediate plate 34. Fixing the cover 25 to the peripheral edge zone 33 by means of said intermediate plates 34 is particularly advantageous in that it makes it possible to absorb the forces exerted on the cover 25 when the pressure prevailing inside the tank is greater than atmospheric pressure and thus makes it possible to relieve the weld line 31 which is produced, further outside the dome structure 19, and which ensures the sealing of the fixing of the cover 25 to the seat wall 23. In addition, the intermediate plates 34 are advantageous in that they make it possible to distribute the forces over a larger weld surface. In addition, the intermediate plates 34 constitute an intermediate stiffness between the cover 25 and the seat wall 23 which is able to deform elastically when the pressure prevailing inside the tank is greater than atmospheric pressure in order to absorb in part of the forces exerted on the cover 25. Finally, as the lines of

welds

36, 37, 38 ensuring the fixing of the cover 25 to the peripheral edge zone of the seat wall 23 are positioned as close as possible to the center of the dome structure 19, the moment exerted on these

weld lines

36, 37, 38, in the event of overpressure in the tank, is reduced.

Furthermore, as shown in the , the dome structure 19 comprises a profiled frame 40 against which the primary sealing membrane 17 is welded and which constitutes a stopping zone of the primary sealing membrane, that is to say a zone, located at the top of the dome structure 19, in which the primary sealing membrane 17 of the vessel walls mounted against the dome walls 22 is anchored to the load-bearing structure 1. The profiled frame 40 is welded to the peripheral edge zone 33 of the seat wall 23, continuously all around it in order to seal the primary sealing membrane 17.

Under the effect of its thermal contraction, the primary sealing membrane 17 exerts on the peripheral edge zone 33 of the seat wall 23 a force directed in a direction opposite to the forces exerted on said peripheral edge zone 33 in due to the pressure forces exerted on the lid 25. Such an arrangement therefore makes it possible to further limit the bending of the seat wall 23 and of the lid 25.

As shown in Figures 4 and 8, the profiled frame 40 has an L-shaped section, that is to say it comprises a first wing 41 and a second wing 42 which are perpendicular to one another. other. The first wing 41 extends vertically, in the plane of the primary sealing membrane 17. The first wing 41 has a free end which is welded to the peripheral edge zone 33 of the seat wall 23 by the weld 43. In addition, at the top of the dome structure 19, the primary sealing membrane 17 rests against the first wing 41 and is welded thereto. The second wing 42 extends parallel to the thickness direction of the wall. It is further welded via weld 45 against a fixing lug 44 which projects vertically downward from the peripheral edge zone 33 of the seat wall 23.

According to a variant embodiment shown in the , the profiled frame 40 comprises reinforcing gussets 46 which each have a first edge bearing against the first flange 41 of the profiled frame 40 and a second edge bearing against the second flange 42 of the profiled frame 40.

The dome structure 19 also includes a secondary closure plate 50, partially illustrated in the which is welded to the peripheral edge zone 33 of the seat wall 23, in a continuous manner all around the latter, and on which is fixed the secondary sealing membrane of the vessel walls mounted against the dome walls 22.

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

With reference to the , 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 tank 71 comprises a primary leaktight barrier intended to be in contact with the LNG contained in the tank, a secondary leaktight barrier arranged between the primary leaktight 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.

The represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipeline 76 and an installation on land 77. The loading and unloading station 75 is a fixed offshore installation comprising a mobile 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 be connected to the loading/unloading pipes 73. The orientable mobile arm 74 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 shore installation 77. This 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 includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention, as defined by the claims.

The use of the verb "to comprise", "to understand" or "to include" and of 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

Installation for storing a liquefied gas comprising a supporting structure (1) and a sealed and thermally insulating tank arranged in the supporting structure (1), the supporting structure (1) comprising an upper supporting wall (3) and the tank comprising a ceiling wall (11) fixed to the upper load-bearing wall (3), the upper load-bearing wall (3) and the ceiling wall (11) being locally interrupted so as to delimit an opening (18), the load-bearing structure (1) comprising a dome structure (19) projecting vertically towards the outside of the tank from the upper load-bearing wall (3) around the opening and defining a passage (24) intended to be traversed by at least one conduit (20, 21) intended for loading or unloading liquefied gas from the tank, the dome structure (19) comprising dome walls (22) projecting from the upper bearing wall (3) and each comprising an upper end, the dome (19) com carrying a seat wall (23) fixed to the upper ends of the dome walls (22), the seat wall (23) developing horizontally and having a peripheral border zone (33) which borders the passage (24) and which makes projecting towards the passage (24) from the vertical dome walls (22), the dome structure (19) having a cover (25) which covers the passage and is sealed to the seat wall (23), said lid (25) being welded to at least one intermediate plate (34), said intermediate plate (34) being welded to the seat wall (23) in the peripheral edge area (33).
Installation according to claim 1, in which the intermediate plate (34) is welded to the peripheral edge zone (33) along an internal edge (37) of the peripheral edge zone (33).
Installation according to claim 2, in which the cover (25) is welded to a plurality of intermediate plates (34) which are arranged around the passage and which are each welded to the seat wall (23) in the peripheral edge zone ( 33), along the inner edge (37) of the peripheral edge area (33).
Installation according to any one of claims 1 to 3, in which the or each intermediate plate (34) projects inwardly from the dome structure (19) and in which the intermediate plate (34) is welded to the cover ( 25) via at least one weld line (35, 36) extending along at least one edge of the intermediate plate (34).
Installation according to Claim 4 taken in combination with Claim 2, in which the or each intermediate plate (34) is welded to the cover (25) via at least two weld lines (35, 36) extending along at least two edges of the intermediate plate (34) arranged on either side of the internal edge (37) of the peripheral edge zone (33).
Installation according to any one of Claims 1 to 5, in which the cover (25) is sealed to the seat wall (23) via an intermediate frame (28) which is arranged around the passage (24) and around the at least one intermediate plate (34).
Installation according to claim 6, in which the intermediate frame (28) is welded to the seat wall (23) by means of at least one tight weld line (29, 30) extending along a peripheral edge internal or external to the middle manager (28).
Installation according to Claim 6 or 7, in which the cover (25) is welded to the intermediate frame (28) by means of at least one tight weld line (31), the at least one tight weld line (31) preferably extending along an outer peripheral edge (39) of the cover (25).
Installation according to any one of Claims 1 to 8, in which the vessel comprises a vessel wall anchored against each of the dome walls (22), each vessel wall comprising a primary sealing membrane (17) intended to be in contact with the liquefied gas contained in the tank, the dome structure (19) comprising a profiled frame (40) against which the primary sealing membrane (17) is welded and which is welded by a sealing line (43) to the peripheral edge area (33) of the seat wall (23).
Installation according to Claim 9, in which the profiled frame (40) has an L-shaped section which comprises a first wing (41) and a second wing (42) perpendicular to each other, the first wing (41 ) being welded to the primary waterproofing membrane (17) and to the peripheral edge zone (33) and extending vertically and the second wing (42) extending horizontally and being fixed to a fixing lug (44) which protrudes towards the ceiling wall (11) from the peripheral edge area (33) of the seat wall (23).
Installation according to claim 10, in which the profiled frame (40) comprises reinforcing gussets (46) each of which has a first edge bearing against the first wing (41) and a second edge bearing against the second wing (42) .
Installation according to any one of claims 1 to 11, comprising a loading/unloading tower (26) passing through the passage (24) defined by the dome structure (19), the loading/unloading tower (26) comprising at least two vertical masts passing through the cover (25) and fixed to each other by crosspieces (27), the two vertical masts each forming a pipe for loading or unloading the tank.
Installation according to any one of claims 1 to 12, in which the ceiling wall (11) as well as each vessel wall anchored against one of the vertical dome walls (22) comprises a secondary thermally insulating barrier (12) retained against the supporting structure (1), a secondary sealing membrane (14) resting against the secondary thermally insulating barrier (12), a primary thermally insulating barrier (15) resting against the secondary sealing membrane (14) and a membrane primary seal (17) which rests against the primary thermally insulating barrier (15) and which is intended to be in contact with the liquefied gas contained in the tank.
Vessel (70) for the transport of a fluid, the vessel comprising an installation according to any one of claims 1 to 13.
Transfer system for a fluid, the system comprising a vessel (70) according to claim 14, insulated pipes (73, 79, 76, 81) arranged to connect the tank (71) of the vessel to a floating storage installation or land (77) and a pump for driving a fluid through the insulated pipes from or to the floating or land storage facility to or from the ship's tank.
Method of loading or unloading a ship (70) according to claim 14, in which a fluid is conveyed through insulated pipes (73, 79, 76, 81) from or to a floating or terrestrial storage installation (77) to or from the ship's tank (71).