EP4198375A1 - Liquefied gas storage facility comprising a vessel and a dome structure - Google Patents

Abstract

The invention relates to a storage facility for a liquefied gas comprising a support structure (1), a sealed and thermally insulating tank arranged in the support structure (1) and a dome structure (19) passing through an opening (18) made in a ceiling wall (11) of the tank and in an upper load-bearing wall (3), the dome structure (19) comprising a shaft (22) which extends along the direction of thickness, is fixed to the upper load-bearing wall (3) and is welded in a leaktight manner to the sealing membrane (17) of the ceiling wall (11), said shaft (22) comprising a lower end (33) which is directed towards the internal space of the tank and a closing plate (25) which is positioned opposite the lower end (33) of the drum (22) so as to cover it, the storage installation comprising at least one pipe (20 , 21, 31), intended to conduct liquefied gas, which passes through the dome structure (19) and the orifice (27, 28, 29) provided in the closure plate (25).

Description

Technical area

The invention relates to the field of storage facilities for liquefied gas comprising a sealed and thermally insulating tank for the storage and/or transport of a liquefied gas, 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 at atmospheric pressure.

These installations can be installed on land or on a floating structure. In the case of a floating structure, the tank of the installation can be intended for the transport of liquefied gas or to receive liquefied gas serving as fuel for the propulsion of the floating structure.

The invention relates more particularly to a storage installation for a liquefied gas comprising a dome structure which passes through an opening made in the ceiling wall of the tank.

Technology background

The document WO2019215414 discloses a storage facility for a liquefied gas comprising a support structure formed by the double hull of a ship and a sealed and thermally insulating tank which is housed inside the support structure. The walls of the vessel have a multilayer structure comprising successively, from the outside inwards, a secondary thermally insulating barrier, a secondary sealing membrane, a primary thermally insulating barrier and a primary sealing membrane intended to be in contact with the liquefied gas stored in the tank. The upper wall of the tank comprises, close to the rear wall of the support structure, a space, of rectangular parallelepipedic shape, projecting upwards, called the liquid dome. The vessel includes a loading/unloading tower which comprises three hollow masts which pass through a cover of the liquid dome and which define either a loading or unloading line allowing the loading or unloading of fluid to or from the tank, or a well of emergency allowing the lowering of an emergency pump and an unloading line in the event of failure of the other pumps unloading. Such a liquid dome is not fully satisfactory. In particular, the inside of the liquid dome is liable to be subjected to dynamic pressures due to the “sloshing” phenomenon, that is to say the movement of the cargo in the tank. In addition, the thermal insulation is ensured by insulating blocks fixed inside the liquid dome while the sealing of the liquid dome is ensured by a sealing membrane which is fixed to the thermally insulating barrier and which is connected tightly to the primary sealing membrane of the upper wall of the tank. Thus, the structure of such a liquid dome is relatively complex to manufacture.

Summary

One idea underlying the invention is to provide a sealed and thermally insulating tank comprising a dome structure which is protected against the movements of the liquefied gas inside the tank.

Another idea at the basis of the invention is to propose a sealed and thermally insulating tank equipped with a dome structure which has a structure that is simple to manufacture.

According to one embodiment, the invention provides a storage facility for a liquefied gas comprising a supporting structure and a leaktight and thermally insulating tank arranged in the supporting structure, said leaktight and thermally insulating tank having an internal space, the supporting structure comprising an upper load-bearing wall and the tank comprising a ceiling wall fixed to the upper load-bearing wall, the ceiling wall comprising, in a direction of thickness from the outside towards the inside of the tank, at least one thermally insulating barrier and at least one sealing membrane supported by the thermally insulating barrier and intended to be in contact with the liquefied gas contained in the tank, the storage facility comprising a dome structure passing through an opening made in the wall ceiling and in the upper load-bearing wall, the dome structure comprising a shaft which extends along the direction of thickness, said shaft comprising a lower end which is directed towards the internal space of the tank and at least one closure which is positioned opposite the lower end of the drum so as to cover it, the closure plate comprising at least one orifice, the storage installation comprising at least one pipe which is intended to carry liquefied gas, said pipe passing through the dome structure and through the hole in the closure plate.

Thus, the closing plate makes it possible to protect the dome structure against the movements of the liquefied gas inside the tank.

According to other advantageous embodiments, such a sealed and thermally insulating tank may have one or more of the following characteristics.

According to one embodiment, the drum is cylindrical in shape with a circular section.

According to one embodiment, the barrel is fixed to the upper load-bearing wall.

According to one embodiment, the barrel is welded in a sealed manner to the sealing membrane of the ceiling wall.

According to one embodiment, the dome structure comprises a ceiling which is fixed, for example by welding, to an upper end of the shaft.

According to one embodiment, the ceiling is curved, which allows the dome structure to withstand greater pressures inside the tank.

According to one embodiment, the closure plate is fixed to the barrel and the pipe is mounted freely, in translation along the direction of thickness, inside the orifice. In other words, the closing plate is not fixed to the pipe but to the barrel, which allows movement of the pipe relative to the closing plate when it is subjected to thermal contraction phenomena, in particular when cooling down or when loading the tank.

According to one embodiment, the closure plate is fixed to the barrel by a plurality of fixing elements.

According to one embodiment, the fixing elements are gussets which are each fixed, on the one hand, to an internal surface of the barrel and, on the other hand, to an upper surface of the closure plate.

According to one embodiment, the gussets are welded to the internal surface of the barrel and welded to the upper surface of the closure plate.

According to another embodiment, the closing plate is fixed to the pipe by means of at least two gussets.

According to one embodiment, each gusset has an edge welded to the pipe and an edge welded to the closure plate, for example to the upper surface of the closure plate.

According to one embodiment, the gussets are oriented radially with respect to the axis of the pipe and are regularly distributed around the axis of the pipe.

According to one embodiment, the pipe to which the closure plate is fixed is centered with respect to the shaft of the dome structure.

According to one embodiment, the installation comprises two closure plates fixed to each other by at least two sheet metal plates forming a spacer maintaining the spacing between the two closure plates.

According to one embodiment, the sheet metal plates also act as stiffeners.

According to one embodiment, the dome structure comprises an insulating lining which fills the interior of the barrel and which rests on the closure plate. Thus, the insulation of the dome structure is effective and easy to install.

According to one embodiment, a mesh is interposed between the insulating gasket and the closure plate. The mesh thus makes it possible to retain the insulating packing in the barrel.

According to one embodiment, the insulating lining is chosen from among glass wool, rock wool and insulating foam, such as polyurethane foam.

According to one embodiment, the insulating lining comprises one or more blocks of foam. According to another embodiment, the insulating lining comprises projected foam.

According to another embodiment, the dome structure includes an insulating gasket which covers an exterior surface of the barrel which protrudes beyond the upper load-bearing wall of the load-bearing structure.

According to one embodiment, the insulating gasket also covers an exterior surface of the ceiling of the dome structure.

According to one embodiment, the pipe is connected to a spray boom which is fixed to the closure plate and which comprises one or more spray nozzles. This allows a simpler installation of the spray boom than when it is fixed to the upper wall of the tank, as in the state of the art.

According to one embodiment, the spray boom has an annular shape.

According to one embodiment, the spray nozzles are distributed around a central axis of the annular shape of the spray boom.

According to one embodiment, the closure plate is placed in the internal space of the sealed and thermally insulating tank. The closure plate is thus located below the lower end of the barrel.

According to one embodiment, the closing plate is arranged in the internal space of the sealed and thermally insulating tank, at a distance from the lower end of the barrel. This makes it possible in particular to facilitate the operations of fixing the closure plate to the barrel.

According to one embodiment, the closure plate extends in a plane which is positioned at a vertical distance from the plane of the lower end of the barrel which is less than 50 cm, advantageously greater than 5 cm and preferably between 10 and 25cm. Thus, such a distance makes it possible to facilitate the operations of fixing the closure plate to the barrel while positioning the closure plate above the maximum loading limit of the tank.

According to one embodiment, in projection in the plane of the lower end of the barrel, the closure plate covers at least 80%, and preferably more than 95% of the section of the lower end of the barrel.

According to one embodiment, the closing plate comprises a plurality of orifices and the liquefied gas storage installation comprises a plurality of pipes intended to conduct liquefied gas, each pipe passing through the dome structure and passing through one of the holes in the cover plate.

According to one embodiment, at least one of the pipes is intended for unloading liquefied gas stored in the tank, said pipe extending to close to a bottom wall of the tank and being equipped with a pump unloading.

According to one embodiment at least one of the pipes is intended for loading liquefied gas stored in the tank.

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

According to one embodiment, a vessel for transporting a fluid comprises a hull, such as a double hull, and a storage facility for a liquefied gas mentioned above, the hull of the vessel forming the supporting structure.

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 ship.

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 installed in the hull of the vessel to a floating or terrestrial storage installation and a pump for driving a flow of fluid through the insulated pipes from or to the floating or onshore storage facility to or from the vessel's tank.

Brief description of figures

• [fig.1] La figure 1 est vue en perspective schématique d'une structure porteuse destinée à supporter une cuve étanche et thermique isolante de stockage d'un gaz liquéfié, la structure de dôme n'étant pas représentée.
• [fig.2] La figure 2 est une vue schématique de la structure multicouche des parois de la cuve.
• [fig.3] La figure 3 est une vue schématique en coupe d'une structure de dôme d'une cuve étanche et thermiquement isolante.
• [fig.4] La figure 4 est une vue en perspective de l'extrémité inférieure de la structure de dôme de la figure 3 dans laquelle le dispositif de pulvérisation n'est pas représenté.
• [fig.5] La figure 5 est une vue en perspective, de dessus, de l'extrémité inférieure de la structure de dôme de la figure 3.
• [fig.6] La figure 6 est une vue de dessous de la structure de dôme de la figure 3.
• [fig.7] La figure 7 est une vue en coupe d'une structure de dôme d'une cuve étanche et thermiquement isolante selon un autre mode de réalisation.
• [fig.8] La figure 8 est une vue détaillée de la conduite et des plaques de fermeture de la figure .
• [fig.9] La figure 9 une vue en coupe d'une structure de dôme d'une cuve étanche et thermiquement isolante selon encore un autre mode de réalisation.
• [fig.10] La figure 10 est une représentation schématique écorchée d'un navire comportant une cuve de stockage de gaz naturel liquéfié 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 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.

• [ fig.1 ] There figure 1 is a schematic perspective view of a supporting structure intended to support a sealed and thermally insulating tank for storing a liquefied gas, the dome structure not being shown.
• [ fig.2 ] There figure 2 is a schematic view of the multi-layered structure of the vessel walls.
• [ fig.3 ] There picture 3 is a schematic sectional view of a dome structure of a sealed and thermally insulating tank.
• [ fig.4 ] There figure 4 is a perspective view of the lower end of the dome structure of the picture 3 in which the spray device is not shown.
• [ fig.5 ] There figure 5 is a perspective view, from above, of the lower end of the dome structure of the picture 3 .
• [ fig.6 ] There figure 6 is a bottom view of the dome structure of the picture 3 .
• [ fig.7 ] There figure 7 is a sectional view of a dome structure of a sealed and thermally insulating tank according to another embodiment.
• [ fig.8 ] There figure 8 is a detailed view of the conduit and closure plates in Fig.
• [ fig.9 ] There figure 9 a sectional view of a dome structure of a sealed and thermally insulating tank according to yet another embodiment.
• [ fig.10 ] There figure 10 is a cutaway schematic representation of a ship comprising a liquefied natural gas storage tank and a loading/unloading terminal for this tank.

Description of embodiments

In relation to the figure 1 , 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 2 is represented on the figure 1 . 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 and which thus define an internal space intended to contain the liquefied gas.

As shown on the figure 2 , 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 seal 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. By way of example, such membrane tanks are described in particular in the patent applications WO14057221 , FR2691520 And FR2877638 targeting respectively the Mark V ^® , Mark III ^® and NO96 ^® products developed by the plaintiff.

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, ethane or a liquefied petroleum gas (LPG), that is to say a mixture of hydrocarbons resulting from the refining of petroleum comprising essentially propane and butane.

As shown on the picture 3 , the upper load-bearing wall 3 as well as the ceiling wall 11 of the tank are locally interrupted so as to delimit an opening 18. The tank also comprises a dome structure 19 which projects upwards from the upper load-bearing wall 3 around the opening 18 and which defines a passage 24 which is traversed by pipes 20, 21, 31 intended respectively for loading the tank with the liquefied gas, for unloading it or for cooling it.

The dome structure 19 comprises a barrel 22 which extends along the thickness direction of the ceiling wall 11. The barrel 22 is cylindrical in shape with a circular section. The dome structure 19 also includes a ceiling 23 which is welded to the upper end of the barrel 22. The ceiling 23 is advantageously domed with a concavity directed downwards, which allows the dome structure 19 to resist pressures greater inside the tank. The lower end 33 of the barrel 22 is directed towards the internal space of the tank and is welded in a sealed manner to the primary sealing membrane 17. The barrel 22 and the ceiling 23 are, for example, made of stainless steel. The barrel 22 is fixed to the upper load-bearing wall 3, for example by means of an annular fixing device 32.

Further, the dome structure 19 includes a closure plate 25 which is attached to the barrel 22. The closure plate 25 is attached to the lower end of the barrel 22 by a plurality of gussets 26, shown in the figures. figure 4 And 5 . The gussets 26 are regularly distributed around the closure plate 25. The gussets 26 are, on the one hand, welded against the internal surface of the barrel 22 and, on the other hand, welded against the upper surface of the closure plate 25 Gussets 26 include here two wings perpendicular to each other and one of which is fixed to the barrel 22 and the other to the closure plate 25.

Closing plate 25 is arranged opposite lower end 33 of shaft 22 so as to cover it at least partially. In the embodiment shown, the closure plate 25 is slightly offset downwards, relative to the lower end 33 of the barrel 22. By way of example, the vertical distance between the plane of the closure plate 25 and that of the lower end 33 of the shaft 22 is less than 50 cm and greater than 5 cm, preferably between 10 and 25 cm. Such a spacing between the closure plate 25 and the lower end 33 of the barrel 22 makes it possible in particular to facilitate the operations of welding the gussets 26 to the closure plate 25.

Advantageously, projected along a vertical axis in the plane of the lower end 33 of shaft 22, closure plate 25 and its orifices 27, 28, 29 cover at least 80%, advantageously at least 90% and preferably 100% of the section of the barrel 22. The closure plate 25 comprises a plurality of orifices 27, 28, 29 through which the pipes 20, 21, 31 pass. The closure plate 25 is advantageously made of stainless steel.

Furthermore, in the embodiment shown, in order to ensure the insulation of the dome structure 19, an insulating gasket 30 is housed in the barrel 22 so as to fill the space inside the barrel 22. According to one embodiment, the insulating lining 30 is chosen from among glass wool and rock wool and insulating foam, such as polyurethane foam for example. When the insulating lining comprises insulating foam, the latter may consist of one or more insulating blocks or be obtained by spraying an expanding foam solution inside the barrel 22.

The insulating gasket 30 rests against the closure plate 25. Advantageously, a mesh 34, shown in the picture 3 , is interposed between the closure plate 25 and the insulating gasket 30 so as to retain the insulating gasket 30 inside the barrel 22. Thus, the closure plate 25 ensures the support of the insulating gasket 30 inside the cask 22.

According to another embodiment not shown, in a complementary or alternative manner to the insulating gasket 30 which is housed in the shaft 22, the shaft 22 and ceiling 23 of the dome structure 19 are covered with insulating gasket on their outer surface projecting of the upper load-bearing wall 3 in order to form a thermal continuity with the thermal insulation of the ceiling wall 11 of the tank.

The closure plate 25 also forms a protection which protects the dome structure 19 and more particularly the barrel 22 as well as the insulating gasket 30 against the phenomena of sloshing of the liquefied gas which would be likely to degrade them.

Furthermore, the closing plate 25 also allows the installation near the ceiling wall 11 of the tank, of a spraying device 35, represented on the figure 3 And 6 , intended to spray liquefied gas into the internal space of the tank. Such a spray device allows in particular the cold setting of the tank, prior to the loading of the liquefied gas inside the tank. This cooling is intended to reduce the temperature inside the vessel, in particular to avoid excessive vaporization of the liquefied gas during loading, to limit the intensity of the thermal stresses in certain components housed in the vessel and to avoid situations likely to affect the safety of the tank and/or its integrity. The spray device 35 comprises the pipe 31 which successively passes through the barrel 22 or the ceiling 23 of the dome structure 19 and the insulating gasket 30 which is housed in the barrel 22. The pipe 31 also passes through the orifice 29 made in the closure plate 25. Line 31 joins a spray boom 36, illustrated in the figure 6 , which is fixed against the lower surface of the closure plate 25.

The spray boom 36 comprises a plurality of spray nozzles 37. The spray nozzles 37 are oriented so as to ensure a distribution of the gas spray in the internal space of the tank. According to the variant embodiment represented, the spray boom 36 has an annular shape and the spray nozzles 37 are regularly distributed around the central axis of said annular shape. The spray boom 36 can be fixed to the internal surface of the closure plate 25 by any appropriate means, such as fixing collars or fixing clips, for example.

Line 20 is intended for loading liquefied gas into the tank. It passes through the barrel 22 and has a bent portion extended by a vertical portion which passes through the closure plate 25. The lower end of the pipe 20 therefore opens into the internal space of the tank. In addition, the pipe 20 is connected outside the tank to a loading pipe which includes a manifold intended to be connected to a maritime or port terminal or to a bunker ship.

Line 21 is intended for discharging liquefied gas from the tank. In the embodiment shown, the pipe 21 passes through the ceiling 23 of the dome structure 19 then passes through the closure plate 25. The pipe 21 extends over substantially the entire height of the tank up to near the bottom wall of the tank. Line 21 is further equipped with an unloading pump, not shown.

The dome structure 19 can also be equipped with level sensors as well as a temperature measuring device which comprises a plurality of temperature sensors which are vertically distributed in the internal space of the tank. The level sensors and the temperature sensors are, for example, mounted along vertical uprights which pass through one of the openings of the closure plate 25 and which each extend along one of the pipes 20 , 21, 31 and are fixed thereto.

THE figures 7 and 8 illustrate a dome structure according to another embodiment. This embodiment differs from that described above in relation to the figures 3 to 6 , in particular in that the installation comprises a conduit 38 for evacuating gas in the vapor phase, in that the dome structure 19 comprises a second closure plate 39 and in that the closure plate 25 as well as the second closure 39 are not attached to shaft 22 of dome structure 19 but directly to pipe 38 . Such a pipe 38 makes it possible to evacuate the gas in the vapor phase from the internal space of the vessel in order to bring it, for example, to the propulsion system of a ship, a reliquefaction unit or a burner.

As shown on the figure 8 , closure plate 25 has an opening through which pipe 38 passes. is welded against the upper surface of the closure plate 25. In the embodiment shown, the closure plate 25 is fixed to an attached lower portion of the pipe 38 which is fixed to the rest of the pipe 38, for example by means of flanges fitted with bolts.

Furthermore, the second closure plate 39 is arranged parallel to the closure plate 25, below the latter and sheet metal plates 41 are arranged between the closure plate 25 and the second closure plate 39 and welded to those -this. The sheet metal plates 41 thus provide the spacer function maintaining the spacing between the two closure plates 25 and 39 and the stiffener function reinforcing the rigidity of the closure plates 25 and 39. In the mode of embodiment shown, the pipe 38 does not pass through the second closure plate 39 but the latter has an opening allowing the passage of gas in the vapor phase so as to allow the gas in the vapor phase stored in the internal space of the vessel to join driving38.

There figure 9 illustrates a dome structure according to yet another embodiment. In this embodiment, the shaft 22 and ceiling 23 of the dome structure 19 are covered with an insulating gasket 42 on their outer surface projecting from the upper load-bearing wall 3 in order to form thermal continuity with the thermal insulation of of the ceiling wall 11 of the tank. Furthermore, the dome structure 19 comprises a gas supply pipe 43 which opens inside the barrel 22 as well as a pipe 44 which passes through an opening made in the closure plate 25 and has a lower end which opens into the internal space of the tank, for example close to its bottom wall. The pipes 43 and 44 are, for example, capable of being used during operations for putting the vessel into operation or maintenance, in particular for its heating, its inerting or its aeration. Thus, by way of example, during the inerting of the tank, an inert gas is injected into the internal space of the tank via the gas supply line 43. The inert gas thus repels the gas making up the initial atmosphere of the tank towards the bottom of the tank, in the manner of a piston, where it is sucked through the pipe 44. It will thus be noted that for such an embodiment in which gas is injected at inside the dome structure 19, it is more advantageous for the insulating lining 42 to be placed outside and not inside the shaft 22 in order to limit pressure drops.

With reference to the figure 10 , 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 sealing membrane intended to be in contact with the LNG contained in the tank, a secondary sealing membrane arranged between the primary sealing membrane and the double hull 72 of the vessel, and two thermally insulating barriers arranged respectively between the primary sealing membrane and the secondary sealing membrane and between the secondary sealing 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 appropriate connectors, to a maritime or port terminal to transfer a cargo of LNG from or to the tank 71.

There figure 10 also shows 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 off-shore 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 (20)

Installation for storing a liquefied gas comprising a supporting structure (1) and a leaktight and thermally insulating tank arranged in the supporting structure (1), said leaktight and thermally insulating tank having an internal space, the supporting structure (1) comprising a upper load-bearing wall (3) and the tank comprising a ceiling wall (11) attached to the upper load-bearing wall (3), the ceiling wall (11) comprising, in a direction of thickness from outside to inside of the tank, at least one thermally insulating barrier (12, 15) and at least one sealing membrane (17) supported by the thermally insulating barrier (12, 15) and intended to be in contact with the liquefied gas contained in the tank, the storage installation comprising a dome structure (19) passing through an opening (18) made in the ceiling wall (11) and in the upper load-bearing wall (3), the dome structure (19) comprising a barrel (22) which extends along the direction of thickness, said barrel (22) comprising a lower end (33) which is directed towards the internal space of the tank and at least one closure plate (25, 39 ) which is positioned opposite the lower end (33) of the barrel (22) so as to cover it, the closure plate (25) comprising at least one orifice (27, 28, 29), the storage facility comprising at least one conduit (20, 21, 31, 38, 44) which is intended to conduct liquefied gas, said conduit (20, 21, 31) passing through the dome structure (19) and passing through the orifice (27, 28, 29) formed in the closure plate (25). Installation for storing a liquefied gas according to claim 1, in which the closure plate (25) is fixed to the barrel (22) and the pipe (20, 21, 31) is mounted freely, in translation in the direction of thickness, inside the orifice (27, 28, 29). A liquefied gas storage facility according to claim 2, wherein the closure plate (25) is attached to the drum (22) by a plurality of fasteners (26). Installation for storing a liquefied gas according to claim 3, in which the fixing elements are gussets (26) which are each fixed, on the one hand, to an inner surface of the barrel (22) and, on the other hand, to an upper surface of the closure plate (25). A liquefied gas storage installation according to claim 1, wherein the closure plate (25) is attached to the pipe (38) by means of at least two gussets (40). Installation for storing a liquefied gas according to any one of claims 1 to 5, comprising two closing plates (25, 39) fixed to each other by at least two sheet metal plates (41) forming a spacer now the distance between the two closing plates (25, 39). Installation for storing a liquefied gas according to any one of claims 1 to 6, in which the dome structure (19) comprises an insulating lining (30) which fills the interior of the drum (22) and which rests on the closing plate (25). Installation for storing a liquefied gas according to claim 7, in which a mesh (34) is interposed between the insulating gasket (30) and the closing plate (25). Installation for storing a liquefied gas according to claim 7 or 8, in which the insulating packing (30) is chosen from among glass wool, rock wool and insulating foam. A liquefied gas storage facility according to any one of claims 1 to 6, wherein the dome structure (19) includes an insulating gasket (42) which covers an outer surface (30) of the drum (22) which forms projecting beyond the upper load-bearing wall (3) of the load-bearing structure (1). Installation for storing a liquefied gas according to any one of claims 1 to 10, in which the pipe is connected to a spray boom (36) which is fixed to the closure plate (25) and which comprises one or more spray nozzles (37). Installation for storing a liquefied gas according to claim 11, in which the spray boom (36) has an annular shape. Installation for storing a liquefied gas according to any one of claims 1 to 12, in which the closure plate (25) is arranged in the internal space of the sealed and thermally insulating tank, at a distance from the end bottom (33) of the barrel (22). Installation for storing a liquefied gas according to any one of claims 1 to 13, in which, in vertical projection in the plane of the lower end (33) of the drum (22), the closure plate (25) covers at least 80% of the section of the lower end (33) of the barrel (22). A liquefied gas storage facility according to any one of claims 1 to 14, wherein the closure plate (25) has a plurality of ports (27, 28, 29) and the liquefied gas storage facility comprises a plurality of conduits (20, 21, 31) for conducting liquefied gas, each conduit (20, 21, 31) passing through the dome structure (19) and passing through one of the orifices (27, 28, 29) formed in the closure plate (25). Installation for storing a liquefied gas according to claim 15, in which at least one of the pipes (21) is intended for the discharge of liquefied gas stored in the tank, the said pipe (21) extending up to the vicinity of a bottom wall of the tank and being equipped with an unloading pump. Installation for storing a liquefied gas according to claim 15 or 16, in which at least one of the pipes (20) is intended for charging liquefied gas stored in the tank. Vessel (70) for the transport of a fluid, the vessel comprising a hull (72) and a storage installation for a liquefied gas according to any one of claims 1 to 17, the hull of the vessel (70) forming the supporting structure. Transfer system for a liquefied gas, the system comprising a ship (70) according to claim 18, insulated pipes (73, 79, 76, 81) arranged so as to connect the tank (71) installed in the hull of the ship to a floating or onshore storage facility (77) and pump for driving fluid through the insulated pipelines from or to the floating or onshore storage facility to or from the vessel's tank. Method of loading or unloading a ship (70) according to claim 18, 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).

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