Liquefied gas storage facility

Abstract

To provide a liquefied gas storage facility.SOLUTION: A liquefied gas storage facility includes a bearing structure and a tank having a ceiling wall. The ceiling wall includes a heat insulation bulkhead and a sealed membrane. The storage facility includes a penetration structure (12) penetrating an opening which is formed in the ceiling wall, the penetration structure (12) being rigidly welded to the sealed membrane and comprising an inner cylinder (18) fixed to an upper bearing wall by a fixing device. The fixing device includes: a fixed ring (20) welded around the inner cylinder (18); a fixed collar (21) extending in a radial direction around the inner cylinder (18) and away from the inner cylinder (18) and welded to the upper bearing wall of the bearing structure; and a supporting outer tube (22) extending around the inner cylinder (18), and welded to the fixed collar (21) at one end and welded to the fixed ring (20) at the other end.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to the field of storage facilities for liquefied gases comprising a sealed, insulated tank with a membrane. In particular, the invention relates to the field of sealed, insulated tanks for storing and / or transporting liquefied gases at low temperatures, such as tanks for transporting liquefied petroleum gas (also called LPG) having a temperature between -50°C and 0°C, or for transporting liquefied natural gas (LNG) at about -162°C at atmospheric pressure. These tanks may be installed on land or on floating structures. In the case of floating structures, the tanks may be intended to transport the liquefied gas or to receive the liquefied gas used as fuel for the propulsion of the floating structure. [Background technology]

[0002] Document KR20140088975 discloses a storage facility for liquefied gas comprising a load-bearing structure formed by a double hull of a ship and a sealed, insulated tank housed inside the load-bearing structure, the storage facility comprising a penetration structure intended to define a circulation path between the interior space of the tank and the outside of the storage facility.

[0003] The penetration structure includes an outer tube that penetrates the outer shell of the double hull and is welded to the inner shell of the double hull, an inner tube that extends inside the outer tube and is firmly connected to the primary sealing membrane of the tank, and an intermediate insulating space disposed between the inner tube and the outer tube.

[0004] The outer cylinder is provided at its upper end with an assembly flange consisting of a lip that is folded outward and receives a removable cover. The inner cylinder and the insulating intermediate space do not extend to the upper end of the inner cylinder, and two ducts pass radially through the outer cylinder in the upper region of the outer cylinder, above the inner cylinder and the insulating intermediate space. The inner cylinder is fixed to the outer cylinder at its upper end.

[0005] Such penetrations are not entirely satisfactory: in fact, given their location and their design, they are complex to assemble, require a significant amount of space within the storage facility and do not allow for the isolation of stresses associated with thermal contraction / expansion during the passage of liquefied gas, which the penetrations of this document transmit directly to the load-bearing structure. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] KR20140088975 [Patent Document 2] WO14057221 [Patent Document 3] FR2691520 [Patent Document 4] FR2877638 Summary of the Invention

[0007] One idea on which the present invention is based is to simplify the penetration structure while strengthening the load-bearing structure and its assembly to the tank.

[0008] Another idea on which the present invention is based is to limit the transmission of stresses associated with the thermal contraction / expansion of the feedthrough structure to the load-bearing structure.

[0009] According to one embodiment, the present invention provides a storage facility for liquefied gas, comprising a load-bearing structure and a sealed, insulated tank arranged in the load-bearing structure, the load-bearing structure comprising an upper load-bearing wall, the tank comprising a ceiling wall, the ceiling wall being fixed to the upper load-bearing wall of the load-bearing structure, the ceiling wall comprises, in the thickness direction from the outside to the inside of the tank, at least one insulating barrier and at least one sealing membrane supported by the insulating barrier and intended to be in contact with the fluid contained in the tank, The storage facility includes a penetration structure that penetrates an opening formed in a ceiling wall and an upper load-bearing wall of the load-bearing structure, The through structure includes an inner tube extending in the thickness direction and penetrating the upper load-bearing wall and the ceiling wall, the inner tube being firmly welded to the sealing membrane and fixed to the upper load-bearing wall by a fixing device; And the fixing device is a fixing ring arranged on the outside of the upper load-bearing wall of the load-bearing structure and welded around the inner tube; a fixing collar extending radially around and at a distance from the inner cylinder and welded to the upper load-bearing wall of the load-bearing structure around the opening; a supporting outer tube that extends around the inner tube and is welded on the one hand to the fixing collar and on the other hand to the fixing ring, thereby ensuring support of the inner tube, the fixing device being configured to allow radial and longitudinal contraction of the inner tube; The present invention provides a storage facility for liquefied gas, comprising:

[0010] Thanks to these features, the lead-through is simplified, in particular by having only a single barrel and by reducing the number of elements to be assembled. Furthermore, its size is reduced by the absence of an outer barrel covering the inner barrel, facilitating its assembly and handling. Finally, the fixing device makes it possible to absorb the stresses associated with the thermal contraction / expansion of the inner barrel during the passage of liquefied gas, thus reducing the stresses in the load-bearing structure and / or the lead-through.

[0011] The thickness direction is therefore defined as the thickness direction of the ceiling wall.

[0012] According to an embodiment, such a facility may include one or more of the following features:

[0013] According to one embodiment, the fixation collar is flat.

[0014] According to one embodiment, the upper load-bearing wall comprises a plurality of load-bearing metal sheets welded to one another, at least one load-bearing metal sheet bounding said opening, and a fixing collar welded to said at least one load-bearing metal sheet.

[0015] According to one embodiment, the fixing collar is formed in the same plane as at least one load-bearing metal sheet bounding said opening.

[0016] According to one embodiment, a fixing collar is welded in overlap with said at least one load-bearing metal sheet.

[0017] According to one embodiment, the fixing collar is of annular form and has an outer contour welded to the upper load-bearing wall of the load-bearing structure and an inner contour located at a distance from the inner tube, the outer tube being welded to the fixing collar at a distance from the inner contour such that the fixing collar portion protrudes from the outer tube towards the inner tube.

[0018] According to one embodiment, the fixing collar is formed by an assembly of several plates.

[0019] According to one embodiment, the outer tube and the inner cylinder are coaxial, the outer tube being located between the fixing collar and the fixing ring in the thickness direction. The outer tube and / or the inner cylinder are manufactured, for example, using rolled metal sheet.

[0020] According to one embodiment, the outer tube has an upper end welded to a fixing ring and a lower end welded to a fixing flange.

[0021] According to one embodiment, the locking ring comprises an annular plate formed and welded all around the inner cylinder, the annular plate lying in a plane parallel to the locking collar, and one end of the outer tube being welded to the annular plate.

[0022] According to one embodiment, the storage facility comprises an inert gas input duct, which passes through the fixing device so that the insulating barrier is in communication with the inert gas.

[0023] The inert gas input duct therefore makes it possible to avoid penetrating the inner tube, the upper load-bearing wall when penetrating the fixing device, and, if a secondary sealing membrane is present, to limit the number of crossings required to reach the insulating barrier without having to penetrate the secondary sealing membrane, making it possible to create an inert atmosphere within this barrier.

[0024] According to one embodiment, an inert gas input duct passes through the fixing device at the annular plate and at said fixing collar.

[0025] According to one embodiment, an inert gas input duct passes through the outer tube and the fastening device at said fastening collar.

[0026] According to one embodiment, the annular plate is an inner annular plate and the fixing ring comprises an outer annular plate formed and welded all around the inner cylinder, the outer annular plate lying in a plane parallel to the inner annular plate, the fixing ring comprising stiffeners fixed on the one hand to the inner annular plate and on the other hand to the outer annular plate, the stiffeners being distributed all around the inner cylinder so as to stiffen the fixing ring.

[0027] According to one embodiment, the sealing membrane is a primary sealing membrane, the insulating barrier is a primary insulating barrier, and the ceiling wall comprises, in the wall thickness direction from the outside to the inside of the tank, a secondary insulating barrier fixed to the upper load-bearing wall and a secondary sealing membrane supported by the secondary insulating barrier, said primary insulating barrier being supported by the secondary sealing membrane and said primary sealing membrane being supported by the primary insulating barrier.

[0028] According to one embodiment, the penetration structure comprises a connection collar located inside the tank and welded all around the inner cylinder, the primary sealing membrane being interrupted at a position away from the inner cylinder and welded all around the connection collar via a connection plate.

[0029] According to one embodiment, the secondary sealing membrane terminates at a location remote from the inner cylinder, the sealing membrane being fixed to the fixing collar via a connecting ring extending all around the inner cylinder.

[0030] According to one embodiment, the storage facility comprises a circular stiffener protruding from the outer surface of the fixing collar towards the outside of the tank.

[0031] According to one embodiment, the circular stiffener and the connecting ring are coaxial and have the same diameter, so that the circular stiffener forms an extension of the connecting ring on the outside of the tank.

[0032] According to one embodiment, the penetration structure comprises a ceiling, the ceiling being fixed to one end of the inner cylinder protruding from the tank.

[0033] According to one embodiment, the ceiling is dome-shaped.

[0034] The domed ceiling therefore enables the penetration structure to better support the internal pressure of the tank.

[0035] According to one embodiment, the tank is adapted for use at 0 bar (1.01×10 5 Pa) ~ 3 bar (3.01 x 10 5 The device is exposed to an internal pressure of 100 Pa.

[0036] According to one embodiment, the penetration structure comprises at least one duct of a liquefied gas loading duct and a liquefied gas unloading duct, the at least one duct penetrating the ceiling wall of the tank inside the inner cylinder with an end located inside the tank, the ceiling of the penetration structure being welded to the end of the inner cylinder, and the penetration structure forming a dome-shaped structure.

[0037] According to one embodiment, the inner cylinder and the ceiling have an outer surface protruding from the upper load-bearing wall, said outer surface being at least partially, preferably entirely, covered with an insulating packing.

[0038] According to one embodiment, the at least one duct passes through an inner casing or a ceiling of a penetration structure.

[0039] According to one embodiment, the at least one duct comprises a duct portion located outside the penetration, the duct portion comprising an outer surface at least partially covered with a thermal insulating packing.

[0040] According to one embodiment, the stiffeners of the fixing ring are spaced apart from each other by insulating packing.

[0041] According to one embodiment, the ceiling is removably fixed, for example by screwing, to said end of the inner cylinder, and the through-structure forms a manhole structure.

[0042] According to one embodiment, the inner cylinder and the ceiling have an inner surface protruding from the upper load-bearing wall, said outer surface being at least partially covered with a heat insulating packing. Preferably, the inner surface of the ceiling is entirely covered with the heat insulating packing.

[0043] According to one embodiment, the ceiling of the manhole structure is penetrated by at least one level sensor.

[0044] According to one embodiment, the penetration structure is a first penetration structure, the opening is a first opening, and the storage facility comprises a second penetration structure penetrating a second opening made in the ceiling wall and the upper load-bearing wall, the second opening being spaced apart from the first opening, the first penetration structure forming a dome structure, and the second penetration structure forming a manhole structure.

[0045] According to one embodiment, the secondary insulating barrier comprises a plurality of juxtaposed parallelepiped insulating blocks, the secondary sealing membrane comprises a plurality of parallel strakes, the strakes having a flat central portion resting on an upper surface of the insulating blocks of the secondary insulating barrier and two raised edges protruding relative to the central portion towards the primary sealing membrane, the strakes are juxtaposed according to a repeating pattern and rigidly welded to each other at the raised edges, and fixing wings fixed to the insulating blocks of the secondary insulating barrier are positioned between the juxtaposed strakes to hold the secondary sealing membrane on the secondary insulating barrier.

[0046] According to one embodiment, the secondary sealing membrane has a -6 ~7.5×10 -6 K -1 The thermal expansion coefficient of the metal alloy is 0.1.

[0047] According to one embodiment, the primary sealing membrane consists of corrugated stainless steel sheets assembled together to form a continuous layer of sheet, the continuous layer of sheet having two mutually perpendicular series of corrugations.

[0048] According to one embodiment, the fixation device is made from stainless steel.

[0049] Such storage facilities may be, for example, land-based storage facilities for storing LNG, or may be installed on floating, coastal or deep-sea structures, in particular methane tankers, floating storage and regasification units (FSRUs), floating production storage and offshore units (FPSOs), etc. Such storage facilities may also function as fuel tanks in any type of vessel.

[0050] According to one embodiment, a vessel for transporting cryogenic liquid products comprises a double hull and the above-mentioned storage facility arranged within the double hull.

[0051] According to one embodiment, the present invention also provides a cryogenic liquid product transfer system, the system comprising a vessel as described above, an insulated pipeline arranged to connect a tank installed within the vessel's hull to an external floating or on-shore storage facility, and a pump for driving a cryogenic liquid product flow through the insulated pipeline from the external floating or on-shore storage facility to the vessel's tank or from the vessel's tank to the external floating or on-shore storage facility.

[0052] According to one embodiment, the present invention also provides a method for loading or unloading such a vessel, wherein the cryogenic liquid product is transported via an insulated pipeline from an external floating or onshore storage facility to the vessel's tanks or from the vessel's tanks to an external floating or onshore storage facility.

[0053] The invention will be better understood and other objects, details, features and advantages will become more apparent from the following description of some particular embodiments of the invention, given purely by way of example and in a non-limiting manner, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0054] [Figure 1] FIG. 1 shows a partial cross-sectional view of a storage facility according to a first embodiment, comprising a dome structure and a manhole structure above a ceiling wall.

[0055] [Diagram 2] FIG. 2 is a cutaway perspective view of detail II of FIG. 1, showing the dome structure.

[0056] [Diagram 3] FIG. 3 is a cross-sectional view of detail II of FIG. 1, showing the dome structure.

[0057] [Figure 4] FIG. 4 is a cross-sectional view of detail IV of FIG. 1, showing the manhole structure.

[0058] [Diagram 5] FIG. 5 is a partial cross-sectional view of a manhole structure according to the second embodiment.

[0059] [Figure 6] FIG. 6 is a cross-sectional view of a fixture having an inert gas input duct passing therethrough according to one embodiment, with the ceiling wall shown.

[0060] [Figure 7] FIG. 7 shows a cross-sectional view of a fastening device with an inert gas input duct passing through it according to another embodiment.

[0061] [Figure 8] FIG. 8 is a cross-sectional schematic diagram of a methane tanker with storage facilities and a terminal for loading / unloading the tanks. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] In this application, the terms "inner" and "outer" designate the relative position of elements of the storage facility with respect to the inside of the tank, so-called inner elements being closer to the interior of the tank than so-called outer elements.

[0063] The liquefied gas storage facility 71 includes a load-bearing structure 3 formed by a double hull 72 of a ship 70 as shown in FIG. 8, for example, and a tank 1 accommodated inside the load-bearing structure 3 as shown in FIG.

[0064] The tank 1 is a tank with a membrane that allows storing liquefied gas. The tank 1 has a multi-layer structure, notably represented in FIG. 5, and comprises, from the outside to the inside in the thickness direction of the wall, a secondary insulating barrier 2 with an insulating element mounted on a load-bearing structure 3, a secondary sealing membrane 4 mounted on the secondary insulating barrier 2, a primary insulating barrier 5 with an insulating element mounted on the secondary sealing membrane 4, and a primary sealing membrane 6 intended to be in contact with the liquefied gas contained in the tank 1. The primary sealing membrane 6 defines an interior space 7 intended to receive the liquefied gas. By way of example, such tanks with membranes are notably described in patent applications WO14057221, FR2691520 and FR2877638, which are directed respectively to the Mark V®, Mark III® and NO 96® technologies developed by the applicant.

[0065] In the embodiment shown in FIG. 6, the secondary sealing membrane 4 comprises a plurality of parallel strakes. Each strake comprises a flat central portion that rests on the upper surface of the insulating element of the secondary insulating barrier 2 and two raised edges that project relative to the central portion towards the primary sealing membrane 6. The strakes are juxtaposed according to a repeating pattern and are rigidly welded to each other at the raised edges. Fixation wings that are fixed to the insulating elements of the secondary insulating barrier 2 are located between the juxtaposed strakes to hold the secondary sealing membrane 4 on the secondary insulating barrier 2. The primary sealing membrane 6 consists of corrugated stainless steel sheets assembled together to form a continuous layer of metal sheet. The continuous metal sheet layer has two mutually perpendicular series of corrugations.

[0066] The liquefied gas intended to be stored in the tank 1 may in particular be liquefied natural gas (LNG), i.e. a gaseous mixture comprising mostly methane and one or more other hydrocarbons. The liquefied gas may also be ethane or liquefied petroleum gas (LPG), i.e. a mixture of hydrocarbons derived from the refinery of oil comprising essentially propane and butane.

[0067] The tank 1 is in particular a polyhedral tank having a ceiling wall 8 fixed to an upper bearing wall 9 of the bearing structure 3 and a bottom wall 10 fixed to a lower bearing wall 11 of the bearing structure 3 .

[0068] FIG. 1 shows a part of a storage facility 71 in which only a part of the top wall 8 and a corresponding part of the bottom wall 10 are shown.

[0069] As can be seen in Fig. 1, the storage facility 71 comprises two penetration structures 12, 13 penetrating through openings 14, 15 made in the ceiling wall 8 and the upper load-bearing wall 9. The first penetration structure is a dome structure 12 penetrating through the first opening 14, and the second penetration structure is a manhole structure penetrating through the second opening 15. The first opening 14 and the second opening 15 are spaced apart from each other as depicted in Fig. 1.

[0070] The dome structure 12 makes it possible in particular to provide a robust intersection of the ceiling wall 8 for the liquefied gas loading and unloading ducts 14, 15. The manhole structure 13, for its part, makes it possible to retain access for an operator to the interior space 7 of the tank 1, for example for repair works.

[0071] Thus, the loading duct 14 and the unloading duct 15 appear in the inner space 7 of the tank 1 for loading or unloading the liquefied gas from the inner space 7 of the tank 1. Furthermore, as can be seen in Fig. 1, support legs 16 are provided, fixed to the bottom wall 10, and the support legs 16 are provided with guiding devices 17 surrounding the ends of the loading and unloading ducts 14, 15, thereby keeping the loading and unloading ducts 14, 15 within the axis of the dome structure 12.

[0072] The lead-through structures 12, 13, and in particular the fastening of the lead-through structures to the load-bearing structure 3, will be explained in more detail below.

[0073] 2 and 3 show the dome structure 12 in greater detail, and FIGS. 4 and 5 show the manhole structure 13 in greater detail.

[0074] The penetration structures, i.e. the dome structure 12 and the manhole structure 13 described below, have substantially similar structures and differ from each other only by their use, the elements that penetrate them and potentially their dimensions. Also, the manhole structure 13, unlike the dome structure 12, is provided with a removable cover.

[0075] Thus, the penetration structures 12, 13 include an inner tube 18 extending in the wall thickness direction and penetrating the upper bearing wall 9 and the ceiling wall 8. The inner tube 18 is cylindrical with a circular cross section. The inner tube 18 is rigidly welded to the primary sealing membrane 6 and welded to the upper bearing wall 9 by a fixing device 19.

[0076] The fixing device 19 is a fixing ring 20 arranged on the outside of the upper bearing wall 9 and welded around the inner tube 18; a fixing collar 21 extending radially around and at a distance from the inner cylinder 18 and welded to the upper bearing wall 9 around the opening 23; a supporting outer tube 22 which extends around the inner tube 18 and is welded on the one hand to the fixing collar 21 and on the other hand to the fixing ring 20, ensuring the support of the inner tube 18; Equipped with.

[0077] The fixing device 19 allows radial and longitudinal contraction of the inner tube 18. Indeed, when the inner tube 18 contracts, for example in connection with the passage of liquefied gas therein, the fixing device 19 follows the deformation of the inner tube 18 by deforming itself, thereby limiting the stresses in the upper bearing wall 9, the welds or the inner tube 18.

[0078] As can be seen in Figures 2 to 5, the fixing ring 20 comprises an inner annular plate 24 and an outer annular plate 25 formed and welded all around the inner tube 18. The annular plates 24 lie in a plane parallel to the fixing collar 21 and are spaced apart from each other. One end of the outer tube 22 is welded to the inner annular plate 24. The fixing ring 20 further comprises a stiffener 26 fixed on the one hand to the inner annular plate 24 and on the other hand to the outer annular plate 25. The stiffener 26 is, for example, a plate formed in a plane perpendicular to the annular plates 24, 25, one side of the stiffener being in contact with the inner tube 18. The stiffener 26 is distributed all around the inner tube 18 so as to stiffen the fixing ring 20.

[0079] The fixing collar 21 consists of a flat plate formed in the same plane as the at least one load-bearing metal sheet bounding the opening 23 and is welded to said at least one load-bearing metal sheet on the upper load-bearing wall 9. The fixing collar 21 is of annular form and has an outer contour welded to the upper load-bearing wall 9 and an inner contour located at a distance from the inner cylinder 18. The outer tube 22 is welded to the fixing collar 21 at a distance from the inner contour such that a fixing collar portion 27 projects on the outer tube 22 towards the inner cylinder 18. This allows easy welding of the outer tube 22 to the fixing collar 21.

[0080] To assist in fastening the fixing collar 21 to the upper load-bearing wall 9, a support tab 39 is fixed around the entire circumference of the fixing collar 21 and protrudes from the outer contour of the fixing collar 21 in a direction opposite to the inner tube 18 so as to rest on the upper load-bearing wall 9 during fastening of the penetration structures 12, 13.

[0081] As regards the specific features of the dome structure 12, the latter are shown in more detail in Figures 2 and 3. The dome structure 12 comprises a domed ceiling 28 welded to the end of the inner cylinder 18 protruding from the tank 1. Thus, in the case of the dome structure 12, the ceiling 28 and the inner cylinder 18 are inseparable from each other after fastening. The inner cylinder 18 and the ceiling 28 are covered by a thermal insulation packing 40 on their outer surfaces protruding from the upper load-bearing wall in order to form thermal continuity with the insulation of the tank 1.

[0082] In the embodiment shown in figures 1 to 3, the dome structure 12 comprises a liquefied gas loading duct 29 and a liquefied gas unloading duct 30. The unloading duct 30 passes through the ceiling 28 and continues inside the inner cylinder 18 to reach the interior space 7 of the tank 1. The loading duct 29 passes through the inner cylinder 18 and continues inside the inner cylinder 18 to reach the interior space 7 of the tank. In this embodiment, the dome structure may also comprise a level sensor 34 making it possible to measure the level of liquefied gas in the tank 1, and a safety duct 42.

[0083] In another embodiment not shown, the dome structure 12 may be provided, instead of the level sensor and the safety duct, with a liquefied gas spraying system making it possible to spray liquefied gas into the tank 1 before loading of the tank 1 in order to cool the interior space 7, and a vapour exhaust duct making it possible to exhaust gas in the vapour phase from the interior space 7, for example to be transported to the ship's propulsion system or to a reliquefaction unit.

[0084] Concerning the particular features of the manhole structure 13, the latter are shown in more detail in figures 4 and 5 according to two variant embodiments. The manhole structure 13 comprises a domed ceiling 28 removably fixed to the end of the inner cylinder 18 protruding from the tank 1 by means of a fastening system 31 formed, for example, by bolting straps. In the case of the manhole structure 13, the ceiling 28 therefore forms a cover for the manhole structure 13 located above the inner cylinder 18.

[0085] In the embodiment shown in Fig. 4, the manhole structure 13 comprises a liquefied gas spraying system 32 allowing to spray liquefied gas into the tank 1 before loading of the tank 1 in order to cool the internal space 7, and a steam exhaust duct 33 allowing to exhaust gas in the vapor phase from the internal space 7, for example to be transported to the ship's propulsion system or to a reliquefaction unit. The spraying system 32 and the steam exhaust duct 33 penetrate the ceiling 28 by being fixed to the ceiling, and then enter the inner cylinder 18 and reach the internal space 7 of the tank 1. When removing the ceiling 28, for example during repairs, the spraying system 32 and the steam exhaust duct 33 are also removed.

[0086] In the embodiment shown in Fig. 5, the manhole structure 13 comprises a level sensor 34 making it possible to measure the level of the liquefied gas in the tank 1, and a safety duct (not shown). The level sensor 34 passes through the ceiling 28 and is partially located inside the inner cylinder 18. The level sensor 34 is, for example, an optical sensor directed towards the bottom of the tank 1. When the ceiling 28 is removed, for example during repairs, the level sensor 34 is also removed.

[0087] An inert gas, such as nitrogen, is passed through the insulating barriers 2, 5 of the liquefied gas tank 1, in particular to inert the liquefied gas and / or to detect leaks in one of the sealing membranes 4, 6. To add this inert gas inside these barriers 2, 5, the storage facility 71 comprises at least one inert gas input duct 35 penetrating the fixing device 19, as shown in figures 5 and 6.

[0088] In the variant shown in FIG. 6, the inert gas input duct 35 passes through the fixing device 19 at the inner annular plate 24 and the fixing collar part 27, whereas in the variant shown in FIG. 7, the inert gas input duct 35 passes through the fixing device 19 at the outer tube 22 and the fixing collar part 27.

[0089] FIG. 6 also makes it possible to show how the closure of the primary sealing membrane 6 and the secondary sealing membrane 4 is manufactured on the feed-through structures 12, 13.

[0090] In fact, the secondary sealing membrane 4 is interrupted at a position remote from the inner tube 18 and is fixed to the fixing collar 21 via the connecting ring 36 all around the inner tube 18. The secondary sealing membrane 4 is therefore welded to the connecting ring 36 all around the inner tube 18.

[0091] Additionally, a circular stiffener 37 projects outwardly from the outer surface of the fixing collar 21. In the illustrated embodiment, the circular stiffener 37 extends into the extension of the connecting ring 18.

[0092] The primary sealing membrane 6 also terminates at a distance from the inner cylinder 18. The penetration structures 12, 13 are located in the interior space 7 of the tank 1 and comprise a connection collar 38 welded all around the inner cylinder 18. The primary sealing membrane 6 is welded directly to the entirety of the connection collar 38. In an alternative embodiment not shown, the primary sealing membrane 6 may also be welded to the connection collar 38 via a connection plate.

[0093] In figure 6 the insulating elements of the secondary insulating barrier 2 and the primary insulating barrier 5 are represented diagrammatically. These insulating elements may for example be formed by layers of polymer foam, such as fibre reinforced polyurethane foam, to which a top sheet of plywood and / or a bottom sheet of plywood may be fixed.

[0094] Example dimensions: -Diameter of inner cylinder 18: approx. 1160mm, - the protruding height of the dome structure 12 outside the tank 1: approx. 1420 mm, - the protruding height of the manhole structure 13 towards the outside of the tank 1: approx. 1400 mm, Outer diameter of fixing collar 21: approximately 1970 mm.

[0095] With reference to Figure 8, a cross-section of a methane tanker 70 shows a sealed, insulated tank 1 of generally prismatic shape mounted in a double hull 72 of a vessel. The double hull 72 comprises an inner hull and an outer hull. The wall of the tank 1 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 insulating barriers arranged respectively between the primary sealing membrane and the secondary sealing membrane and between the secondary sealing membrane and the double hull 72.

[0096] As is known, to transfer the cargo of LNG to or from the tank 1, an in-loading / out-loading pipeline 73 disposed on the upper deck of the vessel may be connected by suitable connectors to an offshore or port terminal.

[0097] FIG. 8 represents an example of a marine terminal with a loading and unloading station 75, a subsea duct 76 and an onshore facility 77. The loading and unloading station 75 is a fixed offshore facility with a movable arm 74 and a riser 78 supporting the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 that can be connected to a loading / unloading pipeline 73. The orientable movable arm 74 fits all methane tanker templates. Inside the riser 78 extends a link duct, not shown. The loading and unloading station 75 allows loading and unloading of methane tankers 70 from or to the onshore facility 77. The onshore facility 77 comprises a liquefied gas storage tank 80 and a connecting duct 81 connected to the loading and unloading station 75 by a subsea duct 76. The undersea duct 76 allows the transfer of liquefied gas over long distances, for example 5 km, between the loading or unloading station 75 and the onshore facility 77, thereby making it possible to keep the methane tanker 70 a long distance from shore during loading and unloading operations.

[0098] To generate the pressure required for the transfer of liquefied gas, pumps embedded in the vessel 70 and / or pumps installed at the onshore facility 77 and / or pumps installed at the loading and unloading station 75 are implemented.

[0099] Although the invention has been described with reference to several specific embodiments, it is extremely clear that the invention is in no way limited thereto, but encompasses all technical equivalents of the described means and combinations thereof, insofar as the latter are included within the framework of the invention.

[0100] Use of the verb "comprise" or "include" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim.

[0101] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Claims

1. A storage facility (71) for liquefied gas, comprising: a load-bearing structure (3); and a sealed, insulated tank (1) disposed within the load-bearing structure (3), the load-bearing structure (3) comprising an upper load-bearing wall (9); the tank (1) comprising a ceiling wall (8), the ceiling wall (8) being fixed to the upper load-bearing wall (9) of the load-bearing structure (3); said ceiling wall (8) comprises, in the thickness direction from the outside to the inside of said tank (1), at least one insulating barrier (2, 5) and at least one sealing membrane (4, 6) supported by said insulating barrier (2, 5) and intended to be in contact with the fluid contained in said tank (1); The storage facility (71) includes a penetration structure (12, 13) penetrating an opening (23) formed in the ceiling wall (8) and the upper load-bearing wall (9), The through structure (12, 13) includes an inner tube (18) extending in the thickness direction and penetrating the upper load-bearing wall (9) and the ceiling wall (8), the inner tube (18) being firmly welded to the sealing membrane and fixed to the upper load-bearing wall (9) by a fixing device (19); The fixing device (19) a fixing ring (20) arranged on the outside of the upper bearing wall (9) of the bearing structure (3) and welded around the inner tube (18); a fixing collar (21) extending radially around and away from said inner tube (18) and welded around said opening to said upper bearing wall (9) of said bearing structure (3); a supporting outer tube (22) extending around said inner tube (18) and welded on the one hand to said fixing collar (21) and on the other hand to said fixing ring (20), ensuring the support of said inner tube (18); and wherein the fixing device (19) is configured to allow radial and longitudinal contraction of the inner cylinder (18).

2. 2. The storage facility (71) according to claim 1, wherein the fixing collar (21) is of annular shape and has an outer contour welded to the upper load-bearing wall (9) of the load-bearing structure (3) and an inner contour spaced at a distance from the inner tube, and the outer tube (22) is welded to the fixing collar (21) at a distance from the inner contour such that a fixing collar portion (27) protrudes from the outer tube (22) towards the inner tube (18).

3. The storage facility (71) according to claim 1 or claim 2, wherein the outer tube (22) and the inner cylinder (18) are coaxial, and the outer tube (22) is located between the fixing collar (21) and the fixing ring (20) in the thickness direction.

4. 3. The storage facility (71) of claim 1 or claim 2, wherein the fixing ring (20) comprises an annular plate (24) formed and welded entirely around the inner cylinder (18), the annular plate (24) lying in a plane parallel to the fixing collar (21), and one end of the outer tube (22) being welded to the annular plate.

5. 5. The storage facility (71) according to claim 4, further comprising an inert gas inlet duct (35) which penetrates the fixing device (19) at the annular plate and the fixing collar part (27), thereby connecting the insulating barrier with the inert gas without the need to penetrate the inner cylinder (18) or the upper load-bearing wall (9) of the load-bearing structure (3).

6. 5. The storage facility (71) according to claim 4, wherein the annular plate is an inner annular plate (24), the fixing ring (20) comprises an outer annular plate (25) formed and welded all around the inner cylinder, the outer annular plate (25) lying in a plane parallel to the inner annular plate (24), the fixing ring (20) comprises stiffeners (26) fixed on the one hand to the inner annular plate (24) and on the other hand to the outer annular plate (25), the stiffeners (26) being distributed all around the inner cylinder so as to stiffen the fixing ring (20).

7. The storage facility (71) according to claim 1 or claim 2, wherein the sealing membrane is a primary sealing membrane (6), the insulating barrier is a primary insulating barrier (5), and the ceiling wall (8) comprises, in the thickness direction of the wall from the outside to the inside of the tank (1), a secondary insulating barrier (2) fixed to the upper load-bearing wall (9) and a secondary sealing membrane (4) supported by the secondary insulating barrier, the primary insulating barrier being supported by the secondary sealing membrane and the primary sealing membrane being supported by the primary insulating barrier.

8. 8. The storage facility (71) according to claim 7, wherein the penetration structure (12, 13) is located inside the tank (1) and comprises a connection collar (38) welded all around the inner cylinder (18), and the primary sealing membrane (6) is interrupted at a position away from the inner cylinder (18) and welded all around the connection collar (38) via a connection plate.

9. The storage facility (71) of claim 7, wherein the secondary sealing membrane (4) terminates at a position away from the inner cylinder (18), and the secondary sealing membrane (4) is fixed to the fixing collar (21) via a connecting ring (36) extending entirely around the inner cylinder (18).

10. 3. The storage facility (71) according to claim 1 or 2, comprising a circular stiffener (37) protruding from an outer surface of the fixing collar (21) towards the outside of the tank (1).

11. 3. The storage facility (71) of claim 1 or claim 2, wherein the penetration structure (12, 13) comprises a domed ceiling (28), the domed ceiling (28) being fixed to an end of the inner cylinder (18) protruding from the tank (1).

12. 12. The storage facility (71) according to claim 11, wherein the penetration structure (12, 13) comprises at least one duct of a liquefied gas loading duct (29) and a liquefied gas unloading duct (30), the at least one duct (29, 30) penetrating the ceiling wall (8) of the tank inside the inner cylinder (18) to have an end portion located inside the tank (1), the ceiling (28) of the penetration structure (12, 13) being welded to the end portion of the inner cylinder (18), and the penetration structure (12, 13) forming a dome structure (12).

13. 12. The storage facility (71) of claim 11, wherein the ceiling (28) is removably fixed to the end of the inner cylinder (18) and the through-structures (12, 13) form a manhole structure (13).

14. The storage facility (71) according to claim 1 or claim 2, wherein the penetration structure (12, 13) is a first penetration structure (12, 13), the opening is a first opening, the storage facility (71) comprises a second penetration structure penetrating the second opening created in the ceiling wall (8) and the upper load-bearing wall (9), the second opening (12, 13) being spaced apart from the first opening, the first penetration structure (12, 13) forming a dome structure, and the second penetration structure (12, 13) forming a manhole structure.

15. A vessel (70) for transporting cryogenic liquid products, the vessel (70) comprising a double hull (72) and a storage facility (71) according to claim 1 or 2 arranged within said double hull.

16. 16. A transfer system for a cryogenic liquid product comprising a vessel (70) according to claim 15, an insulated pipeline (73, 79, 76, 81) arranged to connect the tank (1) installed in the hull of the vessel to a floating or land-based storage facility (77), and a pump for driving a cryogenic liquid product flow from the floating or land-based storage facility to the vessel tank (1) or from the vessel tank (1) to the floating or land-based storage facility via the insulated pipeline.

17. 16. A method for loading or unloading a vessel (70) as claimed in claim 15, wherein the cryogenic liquid product is transported from a floating or onshore storage facility (77) to the tank (1) of the vessel or from the tank (1) of the vessel to a floating or onshore storage facility (77) via an insulated pipeline (73, 79, 76, 81).

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