Liquefied gas storage facility with a tensioned secondary membrane

Abstract

The invention relates to a liquefied gas storage facility, comprising a supporting structure (2) and a sealed and thermally insulating tank (71) supported by the supporting structure (2) and including a secondary thermally insulating barrier (7) of a ceiling wall (4) including: - at least first and second secondary attachment support members (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 attachment support members (23); the secondary stop beam (38) comprising support brackets (41) which are attached to the secondary stop beam (38); each of the first and second secondary attachment support members (23) comprising an abutment device (42) which is configured to press the secondary stop beam (38) against an abutment surface of each of the first and second secondary attachment support members (23); each abutment device (42) including a support member attached to the secondary cap (24) and a pressure screw (44) which is mounted so as to be movable in the longitudinal direction in a tapped bore provided in the support member and which bears against one of the support brackets (41).

Description

Liquefied gas storage facility with a tensioned secondary membrane

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

[0002] In particular, the invention relates to the field of sealed and thermally insulating tanks for the storage and / or transport of liquefied gas at low temperature, such as tanks for the transport of Liquefied Petroleum Gas (also called LPG) having for example a temperature between -50°C and 0°C, or for the transport of Liquefied Natural Gas (LNG) at approximately -162°C 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 intended for the transport of liquefied gas or for receiving liquefied gas used as fuel for the propulsion of the floating structure.

[0003] The storage facility may be installed on land or on a floating structure. In the case of a floating structure, the facility may 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] WO2023 / 001678 describes a liquefied gas storage facility comprising a tank integrated into the supporting structure of a ship. The walls of the tank have a multi-layer structure comprising, in the thickness direction from the outside to the inside, a secondary thermally insulating barrier retained on the supporting 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 which is attached to the primary thermally insulating barrier and which is intended to be in contact with the liquefied gas stored inside the tank. The secondary sealing membrane comprises a plurality of parallel strakes.Each strake comprises a flat central portion which extends in the longitudinal direction of the tank and two raised edges arranged on either side of the flat central portion and projecting towards the inside of the tank relative to the central portion. Such a secondary waterproofing membrane, commonly referred to as a "tensioned membrane", does not allow the absorption of tensile and compressive forces in the longitudinal direction unlike a corrugated membrane.

[0005] The ceiling wall of the tank is interrupted at a loading / unloading opening through which pipes intended for loading and / or unloading the liquefied gas pass. The secondary sealing membrane is stopped and is directly connected to the supporting structure by means of secondary connecting angles in order to take up 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 linked to the bending of the ship's beam. In order to relieve the secondary connecting angles, the secondary thermally insulating barrier has, along the front transverse edge, a particular arrangement comprising in particular a plurality of secondary metal fixing supports to which secondary stop beams are fixed against which the corresponding secondary connecting angle rests.The secondary mounting brackets comprise a secondary leg with two branches which are anchored to the supporting structure and a secondary cap which is welded to the secondary leg.

[0006] The secondary stop beams are locked in translation in the longitudinal direction. To this end, the secondary fixing supports comprise stop devices which are fixed to the secondary cap of said secondary fixing supports. Each of the ends of the secondary stop beams is thus held in position in the longitudinal direction between a stop device and one end of one of the branches of the secondary foot.

[0007] An idea underlying the invention is to provide a storage installation for a liquefied gas of the aforementioned type in which the translational locking 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 facility comprising a supporting structure and a sealed and thermally insulating tank supported by the supporting structure, the supporting structure comprising an upper supporting wall and the tank comprising a ceiling wall which is fixed to the upper supporting 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 supporting 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 interrupted locally so as to delimit a loading / unloading opening intended to be crossed 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 a first and a second secondary fixing brackets positioned along the first transverse edge; the first and second secondary fixing brackets 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 members;- at least one secondary edge insulating block which is arranged along the first transverse edge, between the first and second secondary fixing supports; and- at least one secondary stop beam which extends along the first transverse edge and rests at least against the secondary cap of each of the first and second secondary fixing supports and against one of the secondary edge insulating blocks, said secondary stop beam being blocked, according to 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 comprising a support fixed to the secondary cap and a pressure screw which is mounted movably in the longitudinal direction in a tapped bore formed in said support and which comes to bear against one of the support angles.,

[0009] Thus, the support angles being interposed between the pressure screws and the stop beam, they prevent punching of the beam in the area of ​​contact with the pressure screws. In addition, the support angles being fixed and pre-assembled on the secondary stop beam, their positioning is done simultaneously when the secondary stop beam is installed, which simplifies the realization of the translational locking function of the secondary stop beam according to the longitudinal direction of installation. Another advantage of the pressure screws is that they allow adjustment of the position of the secondary stop beam according to the longitudinal direction.

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

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

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

[0013] According to an advantageous embodiment, mastic 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 insulation block. This makes it possible to adjust the position of the secondary stop beam 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 legs of the support angles are embedded. This ensures the flatness of the support surface of the secondary stop beam against the secondary cap of the secondary fixing supports and the secondary edge insulating block.

[0015] According to one embodiment, the secondary stop beam comprises at least two cutouts in which the stop device of the first and second secondary fixing supports are respectively housed, the second tab 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 fixing members, such as screws for example. This ensures simple and reliable fixing of the support angles to the secondary stop beam.

[0018] According to one embodiment, the secondary stop beam is equipped with at least one metal stiffening blade which extends in the transverse direction along said secondary stop beam. Such a stiffening blade makes it possible to reinforce the secondary stop beam by increasing its rigidity.

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

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

[0021] According to one embodiment, the support of 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 projects inwardly 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 in a sealed manner through an orifice provided in the secondary waterproofing membrane, a support element which is fitted onto the threaded stud and which bears, in the direction of the upper load-bearing wall against a support zone 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 support element against the support zone(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: blocking the secondary stop beam according to the thickness direction of the ceiling wall and ensuring the fixing of the primary anchoring device to the secondary fixing supports, which further simplifies the structure of the ceiling wall in the area of ​​the loading / unloading opening.

[0026] According to one embodiment, the primary thermally insulating barrier comprises primary edge insulating blocks which are arranged along the first longitudinal edge and which comprise a bearing zone, each bearing element bearing against a bearing zone of two adjacent primary edge insulating blocks. This makes it possible to limit the number of primary anchoring devices required for fixing the primary thermally insulating barrier and, consequently, the number of sealed penetrations of the secondary waterproofing membrane.

[0027] According to one embodiment, the support zones of the primary edge insulating 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 the 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 one end equipped with a recess in 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 waterproofing 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 a land-based storage installation, for example for storing LNG or be installed in a floating, coastal or deep-water structure, in particular an ethane or methane 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 serving as fuel for the propulsion of the floating structure.

[0032] According to one embodiment, the invention relates to a ship for transporting a fluid which comprises an installation of the aforementioned type.

[0033] According to one embodiment, the vessel comprises a double hull which forms the supporting 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 tank to a floating or land-based storage facility and a pump for driving a flow of fluid through the insulated pipes from or to the floating or land-based storage facility to or from the vessel tank.

[0035] According to one embodiment, the invention also provides a method of 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, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes, with reference to the accompanying drawings.

[0037] This is a schematic view of a ship with a storage facility.

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

[0039] This is a longitudinal sectional view of the ceiling wall, close to the rear cofferdam wall.

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

[0041] This is a perspective view of a secondary mounting bracket.

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

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

[0044] This is a schematic cutaway representation of an LNG tank and a loading / unloading terminal for this tank.

[0045] By convention, the terms "external" and "internal" are used to define the relative position of one element with respect to another, with reference to the exterior and interior of the tank. Furthermore, in the figures, the 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, the 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] The represents a ship 70, for example an LNG carrier, for the storage and transport of liquefied gas. The ship 70 comprises a storage facility 1 comprising several tanks 71 arranged in the inner hull of the ship. To this end, the inner hull has a plurality of polyhedral-shaped compartments which are defined by a plurality of load-bearing walls and which are each intended to form a load-bearing structure receiving one of the tanks 71 of the ship 1. The inner hull comprises cofferdam load-bearing walls which extend transversely to the longitudinal direction L of the ship and which delimit cofferdam spaces segmenting 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 82 and rear 83 cofferdam walls are spaced apart in the longitudinal direction L of the ship 70 and are fixed against one and the other of the two load-bearing cofferdam walls.

[0048] In order to load the liquefied gas into the tank and unload it, a loading / unloading opening, not shown in the, is provided in the ceiling wall 4 and through which pipes for loading and / or unloading the liquefied gas pass. The loading / unloading opening is provided in the ceiling wall 4 near the rear cofferdam wall 82 (zone II of the).

[0049] The upper load-bearing wall of the load-bearing structure 2 is also provided with openings allowing the pipes to pass through the load-bearing structure 2. The loading / unloading opening serves as a penetration point for various liquefied natural gas handling equipment, including one or more of the following: a filling line, an emergency pumping line, unloading lines linked to unloading pumps, a spray line, a feed line linked to a spray pump, etc. According to 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 crosspieces. The vertical masts are hollow and thus each define a loading line, a loading line, or an emergency shaft allowing the descent of an emergency shaft.

[0050] The figure represents a perspective view of a ceiling wall 4 from inside the tank in an area close to 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 the, the multi-layer 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 on the upper load-bearing wall 8, a secondary sealing membrane 9 bearing against the secondary thermally insulating barrier 7, a primary thermally insulating barrier 10 bearing against the secondary sealing membrane 9 and a primary sealing membrane 11 bearing 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 the. 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 waterproofing membrane 9 of the ceiling wall 4 comprises a continuous layer of metal strakes, with raised edges. Each strake extends in the longitudinal direction L and comprises a flat central portion resting on the secondary insulating panels 12. Each strake also comprises two raised edges arranged on either side of the flat central portion and projecting towards the inside of the tank relative to the central portion. The strakes are welded by their raised edges to parallel welding supports which are fixed in grooves formed in the internal surface of the secondary insulating panels 12, that is to say the one which is in contact with the secondary waterproofing membrane 9. The strakes are, for example, made of Invar®: that is to say an alloy of iron and nickel whose coefficient of expansion is typically between 1.10 -6 and 2.10 -6 K -1, or in an iron and manganese alloy whose coefficient of expansion is typically between 710 -6 and 9.10 -6 K -1 .

[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 the. The primary insulating panels 13 have a generally parallelepiped shape. The primary insulating panels 13 may 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 which are sandwiched between the base plate and the cover plate and are bonded thereto. The insulating polymer foam may in particular be a polyurethane-based foam, optionally reinforced with fibers, in particular glass fibers.

[0056] The primary waterproofing membrane 11 comprises a plurality of corrugated metal plates juxtaposed in the longitudinal direction L and the transverse direction T, and welded to each other along their edges. The primary waterproofing membrane 11 comprises 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 interrupted locally. Thus, the sealing membranes, primary 11 and secondary 9, as well as the thermally insulating barriers, primary 10 and secondary 7, are interrupted all around the loading / unloading opening 14.

[0058] Returning to the, we observe a cover 15 arranged in the loading / unloading opening 14. The cover 15 comprises a metal sealing wall 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 the seal with the primary sealing membrane 11 of the ceiling wall 4 while the thermal insulation structure 17 provides continuity of the insulation.

[0059] The thermal insulation structure 17 may comprise one or more cover insulating blocks, made for example in the form of boxes comprising a base plate, a cover plate and load-bearing spacers extending, in the thickness direction, between the base plate and the cover plate and delimiting a plurality of compartments filled with an insulating filling, such as perlite, glass wool or rock wool. The cover insulating block(s) comprise holes (not shown) allowing the loading / unloading pipes to pass through.

[0060] The metal sealing wall 16 of the cover 14 comprises, for example, a plurality of metal plates welded to each other. The metal sealing wall 16 further comprises a plurality of cover orifices (not shown) intended to be traversed by the loading / unloading pipes. A metal connecting strip 18 makes it possible to connect in a sealed manner the metal sealing wall 16 of the cover 14 and the primary sealing membrane 11 of the ceiling wall 4, as visible in the.

[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 5 and transverse 6 edges of the loading / unloading opening 14 and is directly connected in a sealed manner 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, in particular visible on the. The secondary connecting angle 19 comprises a first wing 20 and a second wing 21 connected to the first wing 20.The first wing 20 extends in a horizontal plane and is connected to the secondary waterproofing membrane 9 while the second wing 21 extends in a vertical plane and is welded to an anchoring plate 22 secured to the upper load-bearing wall 8. Thus, some of the strakes of the secondary waterproofing 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 capable of transmitting to the secondary connection angle 19 tensile forces linked to the work of the secondary sealing membrane 9, in particular when the tank is cooling. Also, in order to relieve the secondary connection angle 19 and its welding 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 the. 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, at a distance 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 the. It comprises 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 core 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 to the thickness direction of the ceiling wall 4. The central core 28 extends in a plane parallel to the longitudinal direction and to the thickness direction of the ceiling wall 4. The central core 28 is welded to the secondary cap 24 and to the two branches 26, 27. In the embodiment shown, the central core 28 has a U shape.The spacing in the longitudinal direction L between the two branches 26, 27 defines a seat length and makes it possible to oppose the tilting and bending of the secondary connecting angle 19 in this direction.

[0065] The secondary fixing support 23 carries a primary anchoring device 29 intended to ensure the anchoring of 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 fixing members 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 develops in the thickness direction towards the inside of the tank. The threaded stud 32 is intended to pass in a sealed manner through an orifice provided in the secondary sealing membrane 9. The primary anchoring device 29 also comprises a support element 33 which is intended to come into contact with support zones of primary insulating edge blocks 51 of the primary thermally insulating barrier 10, in particular shown in the, which are arranged along the transverse edges 6 of the loading / unloading opening 14. In the embodiment shown, the support zones 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 comprises a nut 34, notably visible on the, which cooperates with the thread of the threaded stud 32 so as to ensure the fixing of the support element 33 on 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 comprises a collar 36 which is positioned around the threaded stud 32 and is intended to be welded in a sealed manner to the secondary sealing membrane 9 all around the orifice crossed by the threaded stud 32.

[0068] Returning to the, it is observed that the secondary thermally insulating barrier 7 also comprises, along the transverse edges 6, secondary insulating edge blocks 37. Each secondary insulating edge block 37 is interposed between two neighboring secondary fixing supports 23. The secondary insulating edge blocks 37 are advantageously glued to the upper load-bearing wall 8, for example by means of mastic. 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 filling, such as perlite, glass wool or rock wool for example.

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

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

[0071] As illustrated in the, 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 stop beams 38 also incorporate, in prefabrication, one or more metal reinforcements, making it possible to increase their rigidity. The metal reinforcements are, for example, metal stiffening blades 40 which are oriented parallel to the length of said secondary stop beams 38, that is to say in the transverse direction of the tank. The metal reinforcements can be fixed to the secondary stop beam 38 by any means, and in particular by fixing screws, by gluing or by riveting.

[0073] According to an advantageous embodiment, sausages 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 edge insulating blocks 37 and / or the secondary caps 24 of the secondary fixing supports 23. This makes it possible to adjust the position of the secondary stop beams 38 according to the thickness direction of the ceiling wall 4.

[0074] As illustrated in the, the secondary stop beams 38 also incorporate support angles 41, L-shaped and made of metal, which serve as support for stop devices 42, visible in particular in FIGS. 4 to 6, and described subsequently. The support angles 41 being harder than the secondary stop beam 38, they make it possible to avoid punching of the secondary stop beams 38 in their contact zones with the stop devices 42. The secondary stop beams 38 also have cutouts 43 which make it possible to receive the stop devices 42 when the secondary stop beams 38 are placed against the secondary fixing supports 23. The support angles 41 each have 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 angles 41 can be fixed to the secondary stop beams 38 by any means and in particular by fixing screws, by gluing or by riveting. Advantageously, the first tab 52 is embedded in a recess provided in the internal surface of the secondary stop beam 38.

[0075] Furthermore, as illustrated in the, each secondary stop beam 38 is locked in translation, in the longitudinal direction L, on the secondary fixing supports 23 with which it cooperates. To do this, each secondary fixing support 23 comprises a stop device 42 which is fixed on the secondary cap 24. The stop device 42 comprises a plate 43 fixed, by welding, perpendicular to the secondary cap 24. In the embodiment shown, in order to reinforce the rigidity of the stop device 42, a reinforcement in the form of a gusset 46 is welded between the plate 43 and the secondary cap 24. The plate 43 comprises two threaded orifices whose axes are oriented parallel to the longitudinal direction L of the tank and which are each crossed by a pressure screw 44.Each pressure screw 44 is intended to come to bear against one of the support angles 41, which has the effect of pressing the corresponding secondary stop beam 38 against one end 45 of a branch 27, which makes it possible to block it in translation in the longitudinal direction L and to adjust the position of the stop beam 38 in 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 which may be exerted by the secondary waterproofing membrane 9 in operation.

[0077] As illustrated in the, the secondary thermally insulating barrier 7 comprises cover plates 47 which are received in counterbores provided 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 waterproofing membrane 9.

[0078] With reference to the, a cutaway view of an LNG carrier ship 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 sealed barrier intended to be in contact with the LNG contained in the tank, a secondary sealed barrier arranged between the primary sealed barrier and the double hull 72 of the ship, and two insulating barriers arranged respectively between the primary sealed barrier and the secondary sealed barrier and between the secondary sealed 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 appropriate connectors, to a maritime or port terminal to transfer a cargo of LNG from or to the tank 71.

[0080] The represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipeline 76 and an onshore installation 77. The loading and unloading station 75 is a fixed offshore installation comprising a mobile arm 74 and a tower 78 which supports the mobile arm 74. The mobile arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading / unloading pipelines 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 onshore installation 77. The latter comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the underwater pipe 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 installation 77 over a long 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.

[0081] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the onshore 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 obvious that it is in no way limited thereto 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", "comprise" or "include" and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

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

Claims

A liquefied gas storage facility comprising a supporting structure (2) and a sealed and thermally insulating tank (71) supported by the supporting structure (2), the supporting structure (2) comprising an upper supporting wall (8) and the tank (71) comprising a ceiling wall (4) which is fixed to the upper supporting 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 supporting 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 interrupted locally so as to delimit a loading / unloading opening (14) intended to be crossed 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 a 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 edge insulating 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 secondary cap (24) of each of the first and second secondary fixing supports (23) and against one of the secondary edge insulating blocks (37), said secondary stop beam (38) being blocked, according to 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 in 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 in the longitudinal direction in a tapped bore provided in said support and which comes to bear against one of the support angles (41)., Liquefied gas storage installation according to claim 1, in which each support angle (41) comprises a first tab (52) which is arranged against an external face of the secondary stop beam (38) and a second tab (45) which is perpendicular to the first tab (52) and against which the pressure screw (44) of the stop device (42) of one of the first and second secondary fixing supports (23) comes to bear. Liquefied gas storage facility according to claim 2, in which the external face of the secondary stop beam (38) has recesses in which the first legs (52) of the support angles (41) are embedded. Liquefied gas storage facility according to claim 2 or 3, in which the secondary stop beam (38) comprises at least two cutouts (43) in which the stop device (42) of the first and second secondary fixing supports (23) are respectively housed and in which the second tab (45) of each of the support angles (41) is positioned against an edge of one of the cutouts (43). Liquefied gas storage facility according to any one of claims 1 to 4, in which the support angles (41) are made of metal. Liquefied gas storage facility according to any one of claims 1 to 5, in which the support angles (41) are fixed to the secondary stop beam (38) by fixing members. Liquefied gas storage facility according to any one of claims 1 to 6, wherein the secondary stop beam (38) is equipped with at least one metal stiffening blade (40) which extends in the transverse direction along said secondary stop beam (38). Liquefied gas storage facility according to any one of claims 1 to 7, wherein the support of 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). Liquefied gas storage installation according to any one of claims 1 to 8, in which the secondary foot (25) comprises 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. A liquefied gas storage facility according to claim 9, wherein the abutment surface of the first and second secondary fixing supports (23) is formed by one end of one of the branches (26, 27) of the secondary foot (25) which projects inwards beyond the secondary cap (24). A liquefied gas storage facility according to any one of claims 1 to 10, comprising a first and a second primary anchoring device (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 in a sealed manner through an orifice provided in the secondary sealing membrane (9), a support element (33) which is fitted onto the threaded stud (32) and which bears, in the direction of the upper load-bearing wall, against a support zone 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 support element (33) against the support zone(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).; Vessel (70) for transporting a liquefied gas, the vessel comprising a liquefied gas storage facility according to any one of claims 1 to 11. A transfer system for a liquefied gas, the system comprising a vessel (70) according to claim 12 and insulated pipes (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). A method of loading or unloading a ship (70), in which a liquefied gas is conveyed through insulated pipes (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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