Liquefied gas storage installation with a tensioned secondary membrane

Abstract

The invention relates to a liquefied gas storage installation comprising a load-bearing structure (2) and a sealed and thermally insulated tank (71) supported by the load-bearing structure (2) and comprising a secondary thermally insulated barrier (7) of a ceiling wall (4) comprising: - at least one first and a second secondary fixing supports (23) positioned along a first transverse edge (T) of a loading / unloading opening (14); - at least one secondary stop beam (38) which extends along the first transverse edge (T) and rests at least against the secondary cap (24) of each of the first and second secondary fixing supports (23); the secondary stop beam (38) comprising support angles (41) which are fixed to the secondary stop beam (38);Each of the first and second secondary fixing supports (23) includes a stop device (42) configured to press the secondary stop beam (38) against a stop surface of each of the first and second secondary fixing supports (23); each stop device (42) includes a support fixed to the secondary cap (24) and a set screw (44) movably mounted in the longitudinal direction in a tapped bore in said support and bearing against one of the support angles (41). Figure for the abbreviation: 6;

Description

Title of the invention: Liquefied gas storage installation with a tensioned secondary membrane technical field

[0001] The invention relates to the field of liquefied gas storage facilities comprising a sealed and thermally insulated tank with a sealed membrane.

[0002] In particular, the invention relates to the field of sealed and thermally insulated tanks for the storage and / or transport of liquefied gases at low temperatures, such as tanks for transporting Liquefied Petroleum Gas (also called LPG) at temperatures ranging, for example, from -50°C to 0°C, or for transporting Liquefied Natural Gas (LNG) at approximately -162°C at atmospheric pressure. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank can be used for transporting liquefied gas or for receiving liquefied gas to serve as fuel for the propulsion of the floating structure.

[0003] The storage facility can be installed on land or on a floating structure. In the case of a floating structure, the facility can be intended for the transport of liquefied gas or for receiving liquefied gas used as fuel for the propulsion of the floating structure. Technological background

[0004] Document WO2023 / 001678 describes a liquefied gas storage installation comprising a tank integrated into the load-bearing structure of a ship. The tank walls have a multilayer structure comprising, in the thickness direction from the outside in, a secondary thermally insulating barrier retained to the load-bearing structure, a secondary sealing membrane attached to the secondary thermally insulating barrier, a primary thermally insulating barrier attached to the secondary thermally insulating barrier through the secondary sealing membrane, and a primary sealing membrane that is attached to the primary thermally insulating barrier and is intended to be in contact with the liquefied gas stored inside the tank. The secondary sealing membrane has a plurality of parallel strakes.Each strake comprises a flat central portion extending along the longitudinal direction of the tank and two raised edges positioned on either side of the flat central portion and projecting inwards towards the tank relative to the central portion. Such a secondary sealing membrane, commonly referred to as a "tensioned membrane," does not allow for the absorption of tensile and compressive forces along the longitudinal direction, unlike a corrugated membrane.

[0005] The tank ceiling wall is interrupted at a loading / unloading opening through which pipes for loading and / or unloading liquefied gas pass. The secondary sealing membrane is stopped and directly connected to the load-bearing structure by means of secondary connecting angles to resist the tensile and compressive forces resulting in particular from the thermal contraction of the secondary sealing membrane and the deformation of the ship's hull due to the deflection of the ship's beam. To relieve the secondary connecting angles, the secondary thermally insulating barrier has, along its forward transverse edge, a specific arrangement comprising, in particular, a plurality of secondary metallic fixing supports to which secondary stop beams are attached, against which the corresponding secondary connecting angle rests.The secondary fixing brackets consist of a secondary foot with two arms that are anchored to the supporting structure and a secondary cap that is welded to the secondary foot.

[0006] The secondary stop beams are blocked from translation along the longitudinal direction. To achieve this, the secondary fixing supports include stop devices that are fixed to the secondary cap of said secondary fixing supports. Each end of the secondary stop beams is thus held in position along the longitudinal direction between a stop device and one end of one of the arms of the secondary foot. Summary of the invention

[0007] An idea underlying the invention is to provide a liquefied gas storage installation of the aforementioned type in which the translational blocking of the secondary stop beams in the longitudinal direction is ensured in a simple and reliable manner.

[0008] According to one embodiment, the invention provides a liquefied gas storage installation comprising a load-bearing structure and a sealed and thermally insulated tank supported by the load-bearing structure, the load-bearing structure having an upper load-bearing wall and the tank having a ceiling wall which is fixed to the upper load-bearing wall, said ceiling wall comprising, in a thickness direction, from the outside to the inside of the tank, a secondary thermally insulating barrier fixed to the upper load-bearing wall, 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 resting against the primary thermally insulating barrier and intended to be in contact with the liquefied gas,said ceiling wall being locally interrupted so as to delimit an opening of , loading / unloading intended to be traversed by loading / unloading pipes, said loading / unloading opening being defined by a first and a second transverse edges, parallel to a transverse direction and a first and a second longitudinal edges parallel to a longitudinal direction perpendicular to the transverse direction; the secondary thermally insulating barrier of the ceiling wall comprising: - at least one first and one second secondary fixing supports positioned along the first transverse edge; the first and second secondary fixing supports each comprising a secondary foot which is anchored to the upper load-bearing wall, a secondary cap which is welded to the secondary foot and which extends parallel to the longitudinal direction, in a plane parallel to the upper load-bearing wall and a plate which is fixed to the secondary cap by fixing devices; - at least one secondary insulating edge block which is arranged along the first transverse edge, between the first and second secondary fixing supports;and - at least one secondary stop beam extending along the first transverse edge and resting at least against the secondary cap of each of the first and second secondary fixing supports and against one of the secondary insulating edge blocks, said secondary stop beam being blocked, in the thickness direction of the ceiling wall, between the plate and the secondary cap of each of the first and second secondary fixing supports; the secondary stop beam comprising support angles which are fixed to the secondary stop beam; each of the first and second secondary fixing supports comprising a stop device which is configured to press the secondary stop beam against a stop surface of said first or second secondary fixing support in order to block the secondary stop beam in translation in the longitudinal direction;Each stop device comprises a support fixed to the secondary cap and a pressure screw which is mounted movably along the longitudinal direction in a tapped bore provided in said support and which bears against one of the support angles.

[0009] Thus, since the support angles are interposed between the pressure screws and the stop beam, they prevent punching of the beam in the area of ​​contact with the pressure screws. Furthermore, as the support angles are fixed and pre-assembled on the secondary stop beam, their positioning is carried out simultaneously during the installation of the secondary stop beam, which simplifies the implementation of the translational locking function of the secondary stop beam in the longitudinal direction of installation. Another advantage of the pressure screws is that they allow adjustment of the position of the secondary stop beam in the longitudinal direction.

[0010] According to embodiments, such an installation may include one or more of the following characteristics.

[0011] According to one embodiment, each support angle comprises a first lug which is disposed against an external face of the secondary stop beam and a second lug which is perpendicular to the first lug and against which the pressure screw of the stop device of one of the first and second secondary fixing supports comes to rest.

[0012] According to one embodiment, the external face of the secondary stop beam rests against the secondary cap of the secondary support devices and against the secondary insulating edge block.

[0013] According to an advantageous embodiment, sealant is interposed, on the one hand, between the external surface of the secondary stop beam and the secondary cap of the secondary support devices and, on the other hand, between the external surface of the secondary stop beam and the secondary edge insulating block. This allows the position of the secondary stop beam to be adjusted according to the thickness direction of the ceiling wall.

[0014] According to one embodiment, the external face of the secondary stop beam has recesses in which the first tabs of the support angles are embedded. This ensures the flatness of the bearing surface of the secondary stop beam against the secondary cap of the secondary fixing supports and the secondary insulating edge block.

[0015] According to one embodiment, the secondary stop beam has at least two cutouts in which the stop device of the first and second secondary fixing support are respectively housed, the second leg of each of the support angles being positioned against an edge of one of the cutouts.

[0016] According to one embodiment, the support angles are made of metal. Thus, the support angles have sufficient mechanical strength to withstand the forces exerted by the pressure screws.

[0017] According to one embodiment, the support angles are fixed to the secondary stop beam by means of fasteners, such as screws for example. This ensures a simple and reliable fixing of the support angles to the secondary stop beam.

[0018] According to one embodiment, the secondary arrest beam is equipped with at least one stiffening metal blade extending transversely along said secondary arrest beam. Such a stiffening blade reinforces the secondary arrest beam by increasing its rigidity.

[0019] According to one embodiment, the stiffening metal blade is fixed against an internal surface of the secondary stop beam.

[0020] According to one embodiment, the inner face of the secondary stop beam has a recess in which the stiffening metal blade is embedded.

[0021] According to one embodiment, the support for the stop devices comprises a plate which is welded to the secondary cap, perpendicular to it, and a gusset-shaped reinforcement which is welded between the plate and the secondary cap.

[0022] According to one embodiment, the secondary foot comprises two branches connected to each other by a central core, the branches extending in planes parallel to the transverse direction.

[0023] According to one embodiment, the abutment surface of the first and second secondary fixing supports is formed by an end of one of the branches of the secondary foot which protrudes inwards beyond the secondary cap.

[0024] According to one embodiment, the installation comprises a first and a second primary anchoring device which are respectively fixed to the first and second secondary fixing supports, each of the first and second primary anchoring devices comprising a threaded stud which passes through in a sealed manner an orifice provided in the secondary sealing membrane, a bearing element which is fitted onto the threaded stud and which bears, in the direction of the upper load-bearing wall against a bearing area of ​​one or more insulating elements of the primary thermally insulating barrier and a nut which is screwed onto the threaded stud so as to hold the bearing element against the bearing area(s) of the insulating elements of the primary thermally insulating barrier; said threaded stud being fixed to the plate of one of the first and second secondary fixing supports.

[0025] The plate thus ensures a dual function, namely: locking the secondary stop beam according to the thickness direction of the ceiling wall and ensuring the attachment of the primary anchoring device to the secondary fixing supports, which makes it possible to further simplify the structure of the ceiling wall in the loading / unloading opening area.

[0026] According to one embodiment, the primary thermally insulating barrier comprises primary edge insulating blocks arranged along the first longitudinal edge and having a bearing area, each bearing element bearing against a bearing area of ​​two adjacent primary edge insulating blocks. This makes it possible to limit the number of primary anchoring devices required to fix the primary thermally insulating barrier and, consequently, the number of watertight penetrations of the secondary waterproofing membrane.

[0027] According to one embodiment, the support areas of the primary insulating edge blocks are formed by cleats.

[0028] According to one embodiment, the plate is fixed to the secondary cap by adjustable fixing members in order to allow relative movement of the plate with respect to the secondary cap, according to the thickness direction of the ceiling wall.

[0029] According to one embodiment, the secondary stop beam has an end equipped with a recess into which the plate is received so that said plate is flush with an internal surface of the secondary stop beam. This ensures the flatness of the support surface against which the first wing of the secondary connecting angle and the secondary sealing membrane are positioned.

[0030] According to one embodiment, the first transverse edge is at the front or rear of the loading / unloading opening.

[0031] An installation according to one of the aforementioned embodiments may be an onshore storage facility, for example for storing LNG, or be installed in a floating structure, whether coastal or deep-water, including an ethane or LNG carrier, a floating storage and regasification unit (FSRU), a 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 used as fuel for the propulsion of the floating structure.

[0032] According to one embodiment, the invention relates to a vessel for the transport of a fluid which includes an installation of the aforementioned type.

[0033] According to one embodiment, the ship comprises a double hull which forms the load-bearing structure.

[0034] According to one embodiment, the invention also provides a transfer system for a fluid, the system comprising the aforementioned vessel, insulated pipes arranged to connect the vessel's tank to a floating or land-based storage facility and a pump to drive a flow of fluid through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

[0035] According to one embodiment, the invention also provides a method for loading or unloading such a vessel, in which a fluid is conveyed through insulated pipes from or to a floating or land-based storage facility to or from the vessel's tank. Brief description of the figures

[0036] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from 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.

[0037] Fig. 1 is a schematic view of a ship comprising a storage facility.

[0038] [Fig.2] is a partial perspective view from below of a ceiling wall according to a first embodiment, in an area near a loading / unloading opening interrupting the ceiling wall of the tank, said view corresponding to detail II of [Fig.1].

[0039] Fig. 3 is a longitudinal cross-sectional view of the ceiling wall, near the rear cofferdam wall.

[0040] Fig. 4 is a partial perspective view of the secondary thermally insulating barrier, along the rear transverse edge of the loading / unloading opening.

[0041] Fig. 5 is a perspective view of a secondary fixing support.

[0042] Figure 6 is a partial cross-sectional view of the thermally insulating barrier. secondary, along the rear transverse edge of the loading / unloading opening.

[0043] Fig. 7 is a perspective view of a beam intended to rest against secondary fixing supports.

[0044] Figure 8 is a schematic cutaway view of a tank of an LNG carrier and a loading / unloading terminal for this tank. Description of embodiments

[0045] By convention, the terms "external" and "internal" are used to define the relative position of one element with respect to another, by reference to the outside and inside of the tank. Furthermore, in the figures, arrows L and T correspond respectively to the longitudinal and transverse directions of the tank, perpendicular to each other. By extension, in the embodiments shown, arrows L and T also correspond to the longitudinal and transverse directions of the ship since, in these embodiments, the tanks have the same orientation as the ship.

[0046] Figure 1 represents a vessel 70, for example, an LNG carrier, for the storage and transport of liquefied gas. The vessel 70 includes a storage facility 1 comprising several tanks 71 arranged in the vessel's inner hull. To this end, the inner hull has a plurality of polyhedral compartments defined by a plurality of load-bearing walls, each of which is intended to form a load-bearing structure receiving one of the vessel's tanks 71. The inner hull includes cofferdam load-bearing walls extending transversely to the longitudinal direction L of the vessel and delimiting cofferdam spaces that segment the inner hull into several compartments.

[0047] Each tank 71 is polyhedral in shape and comprises a plurality of tank walls assembled together and fixed against the load-bearing walls, and in particular a ceiling wall 4, a rear cofferdam wall 82 and a front cofferdam wall 83. The front cofferdam walls 82 and rear 83 are spaced in the longitudinal direction L of the vessel 70 and are fixed against each other of the two load-bearing cofferdam walls.

[0048] In order to load and unload the liquefied gas into the tank, an opening is provided The loading / unloading opening, not shown in [Fig. 1], is formed in the ceiling wall 4 and carries pipes for loading and / or unloading liquefied gas. The loading / unloading opening is located in the ceiling wall 4 near the rear cofferdam wall 82 (zone II of [Fig. 1]).

[0049] The upper load-bearing wall of the support structure 2 is also provided with openings allowing the pipes to pass through the support structure 2. The loading / unloading opening serves as an entry point for various liquefied natural gas handling equipment, including one or more of the following: a filling line, an emergency pumping line, unloading lines connected to unloading pumps, a spraying line, a feed line connected to a spraying pump, etc. In one embodiment, a loading / unloading tower, not shown, passes through the loading / unloading opening. The loading tower has vertical masts that are fixed to each other by cross members. The vertical masts are hollow and thus each defines a loading line, a loading line, or an emergency shaft allowing the descent of an emergency shaft.

[0050] Fig. 2 represents a perspective view of a ceiling wall 4 from inside the tank in an area near the loading / unloading opening 14. The loading / unloading opening 14 has a rectangular shape and is defined by two longitudinal edges 5, parallel to the longitudinal direction L of the tank and two transverse edges 6, parallel to the transverse direction.

[0051] In relation to [Fig.3], the multilayer structure of the ceiling wall 4 is observed. The ceiling wall 4 comprises successively, in the thickness direction, from the outside to the inside of the tank, a secondary thermally insulating barrier 7 retained to the upper load-bearing wall 8, a secondary sealing membrane 9 in support against the secondary thermally insulating barrier 7, a primary thermally insulating barrier 10 in support against the secondary sealing membrane 9 and a primary sealing membrane 11 in support against the primary thermally insulating barrier 10 and intended to be in contact with the liquefied natural gas contained in the tank.

[0052] The secondary thermally insulating barrier 7 comprises a plurality of secondary insulating panels 12 which are anchored to the upper load-bearing wall 8 by means of secondary anchoring devices, not shown in [Fig. 3]. Additionally or alternatively, the secondary insulating panels 12 are bonded to the upper load-bearing wall 8 by means of mastic strips. The secondary insulating panels 12 have a generally parallelepiped shape and are, for example, arranged in parallel rows, in the longitudinal direction L and in the transverse direction T.

[0053] The secondary sealing membrane 9 of the ceiling wall 4 comprises a continuous sheet of metal struts with raised edges. Each strut extends along the longitudinal direction L and has a flat central portion resting on the secondary insulating panels 12. Each strut also has two raised edges positioned on either side of the flat central portion and projecting inwards towards the tank relative to the central portion. The struts are welded by their raised edges to parallel weld supports that are fixed in grooves formed in the inner surface of the secondary insulating panels 12, i.e., the surface in contact with the secondary sealing membrane 9. The struts are, for example, made of Invar®: i.e., an iron-nickel alloy whose coefficient of thermal expansion is typically between 1.10⁶ and 2.106 K 1, or in an iron and manganese alloy whose coefficient of expansion is typically between 7106 and 9.106 K1. .

[0054] The primary thermally insulating barrier 10 comprises a plurality of primary insulating panels 13 which are anchored to the secondary insulating panels 12 by means of primary anchoring devices, also not shown in [Fig. 3]. The primary insulating panels 13 have a generally parallelepiped shape. The primary insulating panels 13 can, in particular, be positioned offset from the secondary insulating panels 12 in the longitudinal direction L, and optionally also in the transverse direction T.

[0055] According to one embodiment, the secondary insulating panels 12 and the primary insulating panels 13 comprise a base plate, a cover plate, and one or more layers of insulating polymer foam sandwiched between the base plate and the cover plate and bonded to them. The insulating polymer foam may, in particular, be a polyurethane-based foam, optionally reinforced with fibers, in particular glass fibers.

[0056] The primary sealing membrane 11 comprises a plurality of juxtaposed corrugated metal plates in the longitudinal direction L and the transverse direction T, and welded to each other along their edges. The primary sealing membrane 11 has corrugations extending parallel to the longitudinal direction L and corrugations extending parallel to the transverse direction T.

[0057] In order to delimit the loading / unloading opening 14, the ceiling wall 4 is locally interrupted. Thus, the primary 11 and secondary 9 sealing membranes, as well as the primary 10 and secondary 7 thermally insulating barriers, are interrupted all around the loading / unloading opening 14.

[0058] Returning to [Fig. 2], a cover 15 is seen disposed in the loading / unloading opening 14. The cover 15 has a sealing wall me metal 16 and a thermal insulation structure 17 located between the metal sealing wall 16 and the upper load-bearing wall 8. The cover 15 is fixed to the upper load-bearing wall 8. The metal sealing wall 16 provides continuity of sealing with the primary sealing membrane 11 of the ceiling wall 4 while the thermal insulation structure 17 provides continuity of insulation.

[0059] The thermal insulation structure 17 may include one or more insulating lid blocks, for example in the form of boxes comprising a base plate, a lid plate, and load-bearing spacers extending in the thickness direction between the base plate and the lid plate and defining a plurality of compartments filled with insulating material, such as perlite, glass wool, or rock wool. The insulating lid block(s) have holes (not shown) allowing the passage of loading / unloading lines.

[0060] The metal sealing wall 16 of the cover 14 comprises, for example, a plurality of metal plates welded together. The metal sealing wall 16 further comprises a plurality of cover openings (not shown) for the loading / unloading pipes to pass through. A metal connecting strip 18 provides a watertight connection between the metal sealing wall 16 of the cover 14 and the primary sealing membrane 11 of the ceiling wall 4, as seen in [Fig. 2].

[0061] If, at the loading / unloading opening 14, the primary sealing membrane 11 is connected to the metal sealing wall 16 of the cover 14, the secondary sealing membrane 9 is interrupted at the longitudinal edges 5 and transverse edges 6 of the loading / unloading opening 14 and is directly and hermetically connected to the upper load-bearing wall 8 in order to seal the separation between the secondary thermally insulating barrier 7 and the cover 14. This connection is made using a secondary connecting angle 19, notably visible in [Fig. 3]. The secondary connecting angle 19 has a first flange 20 and a second flange 21 connected to the first flange 20.The first wing 20 extends in a horizontal plane and is connected to the secondary sealing membrane 9 while the second wing 21 extends in a vertical plane and is welded to an anchor plate 22 attached to the upper load-bearing wall 8. Thus, some of the strakes of the secondary sealing membrane 9 are interrupted by the loading / unloading opening 14 and are connected to the upper load-bearing wall 8.

[0062] At this connection to the upper load-bearing wall 8, the secondary sealing membrane 9 is likely to transmit tensile forces related to the work of the sealing membrane to the secondary connecting angle 19 secondary 9, particularly during tank cooling. Also, in order to relieve the secondary connecting angle 19 and its weld with the secondary sealing membrane 9, the secondary thermally insulating barrier 7 has a particular arrangement along the transverse edges 6 of the loading / unloading opening 14.

[0063] The particular arrangement of the secondary thermally insulating barrier 7, along one of said transverse edges 6, is partially shown in [Fig. 4]. The secondary thermally insulating barrier 7 comprises a plurality of secondary fixing supports 23 which are regularly arranged along said transverse edge 6 of the loading / unloading opening 14, spaced apart from each other in the transverse direction T, and welded to the upper load-bearing wall 8.

[0064] One of said secondary fixing supports 23 is shown in [Fig.5]. It includes a secondary cap 24 which extends parallel to the longitudinal direction, in a plane parallel to the ceiling wall 4. The secondary cap 24 is welded to a secondary foot 25 which is anchored to the upper load-bearing wall 8, for example by welding. The secondary foot 25 comprises two branches 26, 27 connected to each other by a central web 28. The two branches 26, 27 are welded to the two ends of the secondary cap 24 and extend, parallel to each other, in planes parallel to the transverse direction and the thickness direction of the ceiling wall 4. The central web 28 extends in a plane parallel to the longitudinal direction and the thickness direction of the ceiling wall 4. The central web 28 is welded to the secondary cap 24 and to the two branches 26, 27.In the embodiment shown, the central web 28 has a U-shape. The longitudinal distance L between the two arms 26, 27 defines a bearing length and prevents the secondary connecting angle 19 from tipping and bending in this direction.

[0065] The secondary mounting bracket 23 carries a primary anchoring device 29 for anchoring the primary thermally insulating barrier 10. The primary anchoring device 29 is fixed to a plate 30, which is itself fixed to the secondary cap 24 by fasteners 31, such as screws. The longitudinal direction of the plate 30 is parallel to the longitudinal direction of the tank.

[0066] Furthermore, a threaded stud 32 is fixed to said plate 30 and extends in the thickness direction towards the interior of the tank. The threaded stud 32 is intended to pass through a sealing opening in the secondary sealing membrane 9. The primary anchoring device 29 also includes a bearing element 33 which is intended to bear against bearing areas of primary edge insulating blocks 51 of the primary thermally insulating barrier 10, in particular shown in [Fig. 3], which are arranged along the transverse edges 6 of the loading / unloading opening 14. In the embodiment shown, the support areas of the primary insulating edge blocks 51 are, for example, formed by cleats which are fixed to the ends of said primary insulating edge blocks 51.

[0067] Furthermore, the primary anchoring device 25 also includes a nut 34, notably visible in [Fig. 5], which cooperates with the thread of the threaded stud 32 so as to secure the support element 33 to the threaded stud 32, as well as Belleville washers 35 which are mounted on the threaded stud 32 between the nut 34 and the support element 33. The primary anchoring device 25 further includes a collar 36 which is positioned around the threaded stud 32 and is intended to be welded in a watertight manner to the secondary sealing membrane 9 all around the orifice through which the threaded stud 32 passes.

[0068] Returning to [Fig. 4], it can be seen that the secondary thermally insulating barrier 7 also includes, along its transverse edges 6, secondary insulating edge blocks 37. Each secondary insulating edge block 37 is sandwiched between two adjacent secondary fixing supports 23. The secondary insulating edge blocks 37 are advantageously bonded to the upper load-bearing wall 8, for example, by means of sealant. According to another embodiment, not shown, the secondary insulating edge blocks are fixed to the upper load-bearing wall by means of mechanical anchoring devices. The secondary insulating edge blocks 37 are, for example, formed by a wooden box inside which is placed an insulating material, such as perlite, glass wool, or rock wool, for example.

[0069] The secondary thermally insulating barrier 7 further comprises secondary retaining beams 38 against which the first flange 20 of the secondary connecting angle 19 is fixed. The secondary retaining beams 38 are, for example, made of wood. The secondary retaining beams 38 also help to retain the secondary edge insulating blocks 37 against the upper load-bearing wall 8. The secondary retaining beams 38 are thus interposed, along the thickness direction, between the secondary edge insulating blocks 37 and the first flange 20 of the secondary connecting angle 19.

[0070] The secondary stop beams 38 are each fixed straddling two secondary fixing supports 23. In the embodiment shown, the secondary stop beams 38 also rest, in their middle portion, on a secondary fixing support 23. To secure the secondary stop beams 38, the ends of the secondary stop beams 38 are sandwiched between the plate 30 and the secondary cap 24. Since the fixing members 31 are adjustable, the ends of the secondary stop beams 38 are thus locked in the thickness direction of the ceiling wall, between the plate 30 and the secondary cap 24.

[0071] As illustrated in [Fig.7], the secondary stop beams 38 have recesses 39 in which the plates 30 are received so that said plates 30 are substantially flush with the internal surface of the secondary stop beam 38. This ensures the flatness of the support surface against which the first wing 20 of the secondary connecting angle 19 and the secondary sealing membrane 9 are positioned.

[0072] Advantageously, the secondary restraint beams 38 further incorporate, in prefabrication, one or more metal reinforcements, thereby increasing their rigidity. The metal reinforcements are, for example, stiffening metal strips 40 oriented parallel to the length of said secondary restraint beams 38, that is, along the transverse direction of the tank. The metal reinforcements can be fixed to the secondary restraint beam 38 by any means, and in particular by fixing screws, by bonding or by riveting.

[0073] According to an advantageous embodiment, beads or strips of mastic, not illustrated, are positioned between, on the one hand, the secondary stop beams 38 and, on the other hand, the secondary insulating edge blocks 37 and / or the secondary caps 24 of the secondary fixing supports 23. This allows the position of the secondary stop beams 38 to be adjusted according to the thickness direction of the ceiling wall 4.

[0074] As illustrated in [Fig.7], the secondary stop beams 38 also incorporate L-shaped metal support angles 41, which serve as supports for stop devices 42, visible in particular in Figures 4 to 6, and described thereafter. Since the support angles 41 are harder than the secondary stop beam 38, they prevent punching of the secondary stop beams 38 in their contact areas with the stop devices 42. The secondary stop beams 38 also have cutouts 43 which allow the stop devices 42 to be received when the secondary stop beams 38 are placed against the secondary fixing supports 23. Each of the support angles 41 has a first tab 52 which is positioned against the external face of the secondary stop beam 38 and a second tab 45 which is positioned against an edge of one of the aforementioned cutouts 43.The support brackets 41 can be fixed to the secondary stop beams 38 by any means, including fixing screws, gluing, or riveting. Advantageously, the first tab 52 is embedded in a recess formed in the internal surface of the secondary stop beam 38.

[0075] Furthermore, as illustrated in [Fig. 6], each secondary stop beam 38 is blocked in translation, along the longitudinal direction L, on the secondary fixing supports 23 with which it cooperates. To achieve this, each fixing support Secondary 23 includes a stop device 42 which is fixed to the secondary cap 24. The stop device 42 includes a plate 43 fixed, by welding, perpendicular to the secondary cap 24. In the embodiment shown, in order to increase the rigidity of the stop device 42, a gusset-shaped reinforcement 46 is welded between the plate 43 and the secondary cap 24. The plate 43 has two threaded holes whose axes are oriented parallel to the longitudinal direction L of the tank and which are each traversed by a pressure screw 44. Each pressure screw 44 is intended to bear against one of the support angles 41, which has the effect of pressing the corresponding secondary stop beam 38 against an end 45 of a branch 27, thus making it possible to lock it in translation along the longitudinal direction L and to adjust the position of the stop beam 38 along the longitudinal direction L.

[0076] Thus, the secondary stop beams 38 are rigidly supported by the secondary fixing supports 23, both in the longitudinal direction L and in the thickness direction of the ceiling wall 4, which makes it possible to take up the tensile or compressive forces that can be exerted by the secondary sealing membrane 9 in operation.

[0077] As illustrated in [Fig.4], the secondary thermally insulating barrier 7 comprises cover plates 47 which are received in counterbores formed in the secondary stop beams 38 and cover the cutouts 43 receiving the stop devices 42. The cover plates 47 ensure the flatness of the support surface of the secondary sealing membrane 9.

[0078] With reference to [Fig. 8], a cutaway view of an LNG carrier 70 shows a sealed and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the vessel. The wall of the tank 71 comprises a primary watertight barrier intended to be in contact with the LNG contained in the tank, a secondary watertight barrier arranged between the primary watertight barrier and the double hull 72 of the vessel, and two insulating barriers arranged respectively between the primary watertight barrier and the secondary watertight barrier and between the secondary watertight barrier and the double hull 72.

[0079] In a manner known per se, loading / unloading pipelines 73 arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a marine or port terminal to transfer a cargo of LNG from or to the tank 71.

[0080] Figure 8 shows an example of a marine terminal comprising a loading and unloading berth 75, a subsea pipeline 76, and an onshore installation 77. The loading and unloading berth 75 is a fixed offshore installation comprising a movable arm 74 and a tower 78 that supports the movable arm 74. A movable arm 74 carries a bundle of insulated flexible hoses 79 that can be connected to the loading / unloading pipelines 73. The steerable movable arm 74 adapts to all LNG carrier sizes. A connecting pipeline (not shown) extends inside the tower 78. The loading and unloading station 75 allows the LNG carrier 70 to be loaded and unloaded from or to the onshore facility 77. This facility includes liquefied gas storage tanks 80 and connecting pipelines 81 linked by the subsea pipeline 76 to the loading or unloading station 75. The subsea pipeline 76 allows the transfer of liquefied gas between the loading or unloading station 75 and the onshore facility 77 over a long distance, for example 5 km, which allows the LNG carrier 70 to be kept a considerable distance from the coast during loading and unloading operations.

[0081] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the land installation 77 and / or pumps equipping the loading and unloading station 75 are used.

[0082] Although the invention has been described in connection with several particular embodiments, it is clearly evident that it is by no means limited to them and that it includes all 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.

[0083] The use of the verb "comprise", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or other steps than those stated in a claim.

[0084] In the claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

Demands

1. A liquefied gas storage installation comprising a load-bearing structure (2) and a sealed and thermally insulated tank (71) supported by the load-bearing structure (2), the load-bearing structure (2) having an upper load-bearing wall (8) and the tank (71) having a ceiling wall (4) which is fixed to the upper load-bearing wall (8), said ceiling wall (4) comprising, in a thickness direction, from the outside to the inside of the tank, a secondary thermally insulating barrier (7) fixed to the upper load-bearing wall (8), a secondary sealing membrane (9) resting against the secondary thermally insulating barrier (7), a primary thermally insulating barrier (10) resting against the secondary sealing membrane (9), and a primary sealing membrane (11) resting against the primary thermally insulating barrier (10) and intended to be in contact with the liquefied gas,said ceiling wall (4) being locally interrupted so as to delimit a loading / unloading opening (14) intended to be traversed by loading / unloading pipes, said loading / unloading opening (14) being defined by a first and a second transverse edges (6), parallel to a transverse direction (T) and a first and a second longitudinal edges (5) parallel to a longitudinal direction (L) perpendicular to the transverse direction (T); the secondary thermally insulating barrier (7) of the ceiling wall (4) comprising: - at least one first and a second secondary fixing supports (23) positioned along the first transverse edge (T); the first and second secondary fixing supports (23) each comprising a secondary foot (25) which is anchored to the upper load-bearing wall (8), a secondary cap (24) which is welded to the secondary foot (25) and which extends parallel to the longitudinal direction, in a plane parallel to the upper load-bearing wall (8) and a plate (30) which is fixed to the secondary cap (24) by fixing members (31); - at least one secondary insulating edge block (37) which is arranged along the first transverse edge (T), between the first and second secondary fixing supports (23); and - at least one secondary stop beam (38) which extends along the first transverse edge (T) and rests at least against the cap se- secondary (24) of each of the first and second secondary fixing supports (23) and against one of the secondary insulating edge blocks (37), said secondary stop beam (38) being blocked, along the thickness direction of the ceiling wall, between the plate (30) and the secondary cap (24) of each of the first and second secondary fixing supports; the secondary stop beam (38) comprising support angles (41) which are fixed to the secondary stop beam (38); each of the first and second secondary fixing supports (23) comprising a stop device (42) which is configured to press the secondary stop beam (38) against a stop surface of said first or second secondary fixing support (23) in order to block the secondary stop beam (38) in translation along the longitudinal direction;each stop device (42) comprising a support fixed to the secondary cap (24) and a pressure screw (44) which is mounted movably along the longitudinal direction in a tapped bore formed in said support and which bears against one of the support angles (41).

2. Liquefied gas storage installation according to claim 1, in which each support angle (41) has a first lug (52) which is disposed against an external face of the secondary stop beam (38) and a second lug (45) which is perpendicular to the first lug (52) and against which the pressure screw (44) of the stop device (42) of one of the first and second secondary fixing supports (23) bears.

3. Liquefied gas storage installation according to claim 2, wherein the external face of the secondary stop beam (38) has recesses in which the first legs (52) of the support angles (41) are embedded.

4. Liquefied gas storage installation according to claim 2 or 3, wherein the secondary stop beam (38) has at least two cutouts (43) in which the stop device (42) of the first and second secondary fixing support (23) are respectively housed, and in which the second leg (45) of each of the support angles (41) is positioned against an edge of one of the cutouts (43).

5. Liquefied gas storage installation according to any one of claims 1 to 4, wherein the support brackets (41) are made of metal.

6. Liquefied gas storage installation according to any one of claims 1 to 5, wherein the support angles (41) are fixed to the secondary stop beam (38) by fastening devices.

7. Liquefied gas storage installation according to any one of claims 1 to 6, wherein the secondary stop beam (38) is equipped with at least one stiffening metal blade (40) which extends in the transverse direction along said secondary stop beam (38).

8. Liquefied gas storage installation according to any one of claims 1 to 7, wherein the support for the stop devices (42) comprises a plate (43) which is welded to the secondary cap (24), perpendicular to it, and a gusset-shaped reinforcement (46) which is welded between the plate (43) and the secondary cap (24).

9. Liquefied gas storage installation according to any one of claims 1 to 8, wherein the secondary foot (25) has two branches (26, 27) connected to each other by a central core (28), the branches (26, 27) extending in planes parallel to the transverse direction.

10. Liquefied gas storage installation according to claim 9, wherein the abutment surface of the first and second secondary fixing supports (23) is formed by an end of one of the branches (26, 27) of the secondary foot (25) which projects inwards beyond the secondary cap (24).

11. A liquefied gas storage installation according to any one of claims 1 to 10, comprising a first and a second primary anchoring devices (29) which are respectively fixed to the first and second secondary fixing supports (23), each of the first and second primary anchoring devices (29) comprising a threaded stud (32) which passes through a sealed opening in the secondary sealing membrane (9), a bearing element (33) which is fitted onto the threaded stud (32) and which bears, in the direction of the upper load-bearing wall, against a bearing area of ​​one or more insulating elements (51) of the primary thermally insulating barrier (10) and a nut which is screwed onto the threaded stud (32) so as to hold the bearing element (33) against the bearing area(s) of the insulating elements (51) of the primary thermally insulating barrier (10);said threaded stud being fixed to the plate (30) of one of the first and second secondary fixing supports (23).;

12. Vessel (70) for the transport of a liquefied gas, the vessel comprising a liquefied gas storage facility according to any one of claims 1 to 11.

13. Transfer system for a liquefied gas, the system comprising a vessel (70) according to claim 12 and insulated pipelines (73, 79, 76, 81) arranged to connect the tank (71) installed in the hull of the vessel to a floating or land-based storage facility (77).

14. A method of loading or unloading a ship (70), wherein a liquefied gas is conveyed through insulated pipelines (73, 79, 76, 81) from or to a floating or land-based storage facility (77) to or from the tank (71) of the ship (70) according to claim 12.

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