FR3118796A1 - Storage facility for liquefied gas - Google Patents

Abstract

The invention relates to a storage installation comprising a tank comprising at least one ceiling wall (4), the sealing membrane of the ceiling wall comprising a plurality of strakes (15), the ceiling wall being interrupted locally so as to to delimit an opening, the tank comprising a cover (19) arranged in the opening, in which the storage installation comprises a fixing support (26) welded to the upper load-bearing wall (8), the thermally insulating barrier comprising a stop beam (40) disposed on the mounting bracket, the mounting bracket including an abutment device (33) blocking translation of the stop beam in the first direction, in which a metal mounting plate (47) is fixed to the stop beam, an end portion of the or each strake interrupted by the opening being welded to the metal fixing plate, and in which a metal connecting strip (24) connects the wall of tightness of the cover to the metal fixing plate. Figure for the abstract: Fig. 4

Description

Storage facility for liquefied gas

The invention relates to the field of storage facilities for liquefied gas comprising a sealed and thermally insulating tank, with a sealed membrane. 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 around -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 may be intended for the transport of liquefied gas or to receive liquefied gas used as fuel for the propulsion of the floating structure.

Technology background

The document FR2549575 describes a sealed and thermally insulating tank integrated into the load-bearing structure of a ship, comprising a secondary thermally insulating barrier, a secondary sealing membrane, a primary thermally insulating barrier and a primary sealing membrane. The vessel has a plurality of vessel walls joined together. The waterproofing membranes each comprise a plurality of parallel strakes. Each strake has a flat central portion extending in a first direction and two raised edges arranged on either side of the flat central portion and projecting towards the inside of the tank with respect to the central portion. The strakes are thus juxtaposed in a repeated pattern and welded together at the raised edges.

The waterproofing membranes are fixed to the supporting structure in the corners of the tank using connection rings. Each connection ring is therefore fixed on the one hand to the load-bearing structure and on the other hand to the sealing membranes in order to allow the transfer of forces between the membranes and the hull of the ship.

The connection ring allows in particular to take up the tensile and compressive forces resulting from thermal contraction, from the deformation of the hull linked for example to the deflection of the ship's beam, and from the state of filling of the tanks. Indeed, such waterproofing membranes, commonly called stretched membranes, do not have in the first direction zones allowing to absorb the tensile and compressive forces unlike a corrugated membrane.

In this type of structure, the waterproofing membranes are interrupted at the level of an opening in order, for example, to allow the crossing of loading/unloading pipes.

In order to maintain the tightness of the tank, in particular of the primary sealing membrane, connection zones are provided at the level of this opening.

Summary

The invention is based on the observation that during phenomena causing tensile and compressive forces on the waterproofing membranes, the connection zones can be subjected to significant compressive and tensile forces, in particular at the level of the welds, which can cause the seal to break in these areas.

One idea underlying the invention is to improve the resistance to forces of the waterproofing membrane at the level of the connection zones.

According to one embodiment, the invention provides a storage facility for liquefied gas comprising a metal support structure and a sealed and thermally insulating tank arranged in the support structure,
the tank comprising at least one metal sealing membrane defining an internal storage space and at least one thermally insulating barrier, the thermally insulating barrier being placed between the sealing membrane and the supporting structure,
the load-bearing structure comprising an upper load-bearing wall,
the tank comprising at least one ceiling wall fixed to the upper load-bearing wall,
in which the thermally insulating barrier of the ceiling wall comprises juxtaposed insulating blocks,
wherein the ceiling wall sealing membrane has a plurality of parallel strakes extending in a first direction, each strake having a planar central portion resting against the insulating blocks and two raised edges projecting inwardly from the tank with respect to the central portion, the strakes being juxtaposed in a second direction according to a repeated pattern and welded together in a sealed manner at the level of the raised edges, the second direction being perpendicular to the first direction, anchoring flanges anchored to the blocks insulating and parallel to the first direction being arranged between the juxtaposed strakes to retain the sealing membrane on the thermally insulating barrier,
the 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 interrupting at least one said strake,
wherein the tank has a lid disposed in the loading/unloading opening, the lid having a metallic sealing wall and a thermal insulation structure located between the sealing wall and the upper load-bearing wall, the lid being fixed to the upper load-bearing wall,
wherein the insulating blocks have an end insulating block adjacent to the cover in the first direction.

According to one embodiment, the storage installation comprises a fixing support fixed, preferably by welding, to the upper load-bearing wall in line with the end insulating block, the fixing support having a seat length extending in the first direction, the thermally insulating barrier comprising a stop beam arranged on the fixing support, the fixing support comprising a stop device blocking the translation of the stop beam in the first direction,
in which a metal fixing plate is fixed to the stop beam, an end portion of the or each strake interrupted by the loading/unloading opening being welded to the metal fixing plate,
and in which a metal connection strip connects the sealing wall of the cover to the metal fixing plate to ensure the continuity of the sealing membrane of the ceiling wall.

Thanks to these characteristics, the compressive and tensile forces undergone by the waterproofing membrane in the first direction upstream of the connecting strip are taken up by the load-bearing structure using the fixing support and the support beam. stop. Indeed, the fixing plate of the waterproofing membrane is directly fixed to the stop beam of the thermally insulating barrier. The stop beam is for its part blocked in translation in the first direction using the abutment device of the fixing support so that the forces undergone by the stop beam are transmitted to the load-bearing structure using of the mounting bracket. The seat length of the mounting bracket in the first direction makes it possible to offer a sufficiently high rigidity in this direction.

According to embodiments, such a storage facility may comprise one or more of the following characteristics.

According to one embodiment, the storage installation comprises a plurality of fixing brackets juxtaposed in the second direction along an edge of the loading/unloading opening.

According to one embodiment, two adjacent mounting brackets are separated from each other by one or more end insulating blocks.

According to one embodiment, the stop beam has a length extending in the second direction over at least two adjacent fixing supports and a width extending in the first direction.

According to one embodiment, the thermally insulating barrier comprises a plurality of stop beams juxtaposed in the second direction, each stop beam being arranged on two adjacent fixing supports.

According to one embodiment, the sealing membrane comprises a connection angle extending in the second direction to separate the thermally insulating barrier in a leaktight manner from the thermal insulation structure of the cover, the connection angle comprising a first wing and a second wing connected to the first wing, the first wing being welded to the fixing plate and the second wing being connected to the upper bearing wall.

According to one embodiment, the connecting strip comprises a corrugation extending in the second direction.

Thus, the corrugation makes it possible to absorb the residual compressive and tensile forces undergone by the connecting strip which have not been absorbed by the fixing support. Indeed, the corrugation deforms elastically by opening or closing without stressing the welds.

According to one embodiment, the corrugation protrudes towards the internal space of the tank.

According to one embodiment, the corrugation protrudes towards the upper load-bearing wall.

According to one embodiment, the connecting strip comprises two parallel undulations extending in the second direction.

According to embodiments, the connecting strip is welded to the connection angle or to the fixing plate of the waterproofing membrane.

According to one embodiment, the stop beam comprises a first housing, for example a first groove extending in the second direction, and a second housing, for example a second groove extending in the second direction, the device for abutment comprising a first abutment located in the first housing, for example the first groove and being in contact with a wall of the first housing, for example of the first groove, the first abutment blocking the translation of the stop beam in the first direction and in a first direction, the abutment device comprising a second abutment located in the second housing, for example the second groove and being in contact with a wall of the second housing, for example of the second groove, the second abutment blocking the translation of the stop beam in the first direction and in a second direction opposite the first direction.

According to one embodiment, the abutment device is arranged plumb with the fixing plate.

Thus, when transferring tensile and compressive forces from the mounting plate to the mounting bracket, the bending moment is minimized.

According to one embodiment, the sealing membrane, the sealing wall of the lid and/or the connecting strip are made of a metal with a low coefficient of expansion, for example an alloy of iron and nickel having a coefficient of thermal expansion between 0.5.10 ^-6 and 2.10 ^-6 K ^-1 . It is also possible to use alloys of iron and manganese whose coefficient of expansion is typically of the order of 7.10 ^-6 K ^-1 .

According to one embodiment, the fixing support is made of steel, for example carbon steel or stainless steel.

According to one embodiment, the stop beam is made of plywood.

According to one embodiment, the support structure comprises a rear cofferdam wall and a front cofferdam wall being located on either side of the vessel in the first direction, the loading/unloading opening being formed close to one of the cofferdam walls, for example the rear cofferdam wall, the end insulating block and the fixing support being arranged between the cover and the other cofferdam wall, for example the front cofferdam wall.

Thus, the fixing support and the stop beam make it possible to absorb the tensile and compressive forces of the greater part of the waterproofing membrane of the ceiling wall, namely on the portion extending between the lid and front cofferdam wall.

According to one embodiment, the edge of the loading/unloading opening along which the plurality of fixing supports are juxtaposed is a front longitudinal end edge of the loading/unloading opening which is located between the cover and the front cofferdam wall in the first direction.

According to one embodiment, the sealing membrane is a primary sealing membrane intended to be in contact with the liquefied gas, the thermally insulating barrier is a primary thermally insulating barrier and in which the tank further comprises, in one direction thick from the outside to the inside of the tank, a secondary thermally insulating barrier fixed to the support structure, and a secondary metallic sealing membrane arranged between the secondary thermally insulating barrier and the primary thermally insulating barrier.

The secondary waterproofing membrane can be made in various ways. According to one embodiment, the secondary waterproofing membrane of the ceiling wall comprises a plurality of parallel strakes extending in the first direction, each strake comprising a planar central portion resting against the secondary insulating blocks of the secondary thermally insulating barrier and two raised edges projecting towards the inside of the tank with respect to the central portion, the strakes being juxtaposed in the second direction according to a repeated pattern and welded together in a sealed manner at the level of the raised edges, anchoring wings anchored with the secondary insulating blocks parallel to the first direction being arranged between the juxtaposed strakes to retain the secondary sealing membrane on the secondary thermally insulating barrier.

According to one embodiment, the connecting angle is a primary connecting angle, the secondary sealing membrane comprises a secondary connecting angle to separate the secondary thermally insulating barrier from the thermal insulation structure of the cover in leaktight manner, the secondary connection angle comprising a first wing and a second wing connected to the first wing, the first wing of the secondary connection angle being welded to the secondary sealing membrane and the second wing of the secondary connection angle being welded to the upper load-bearing wall.

According to one embodiment, the second wing of the primary connecting angle is welded to the second wing of the secondary connecting angle.

According to one embodiment, the fixing support comprises a secondary support portion welded to the upper bearing wall and a primary support portion welded to the secondary support portion, the stop beam being arranged on the primary support portion, the secondary sealing membrane being welded to the secondary support portion.

According to one embodiment, a dimension of the primary support portion in the first direction is less than a dimension of the stop beam in the first direction, for example less than half the dimension of the stop beam in the first direction.

Since the primary support portion is a metal element passing through the primary thermally insulating barrier in the thickness direction in part, it is advantageous to limit its size in order to limit the thermal bridge between the internal space of the vessel and the exterior while keeping a sufficient size to take up the efforts.

According to one embodiment, the spacing between two adjacent fixing supports in the second direction is equal to an integer multiple of the dimension of a strake in the second direction, for example equal to the dimension of two strakes in the second direction. .

According to one embodiment, the dimension of a strake in the second direction is equal to 500mm.

According to one embodiment, the sealing wall of the lid comprises a plurality of flat metal plates welded to each other, the sealing wall comprising a plurality of orifices intended to be traversed by the loading/unloading pipes.

According to one embodiment, the end portion of the or each strake welded to the metal fixing plate has a thickness greater than the thickness of the strake at a distance from the loading/unloading opening.

The thickness is a dimension measured according to the direction of thickness, namely the direction perpendicular to the first direction and to the second direction.

According to one embodiment, the thickness of the end portion is greater than or equal to 1.5 mm. The thickness of the strakes may be less than 1 mm away from the ends, for example between 0.7 and 1 mm.

According to one embodiment, the thickness of the flat plates of the sealing wall of the cover is equal to 1.5 mm.

According to one embodiment, the thickness of the connecting strip is less than or equal to 1.5 mm, preferably equal to 1 mm.

According to one embodiment, the thickness of the stop beam is greater than or equal to 50mm.

According to one embodiment, the seating length of the secondary support portion in the first direction is greater than or equal to 300mm.

According to one embodiment, the seating length of the primary support portion in the first direction is between 100 and 200mm, for example 165mm.

Such a storage installation can be an onshore storage installation, for example for storing LNG or be a floating, coastal or deep-water structure, in particular an LNG carrier, a floating storage and regasification unit (FSRU), a floating production and remote storage (FPSO) and others. Such an installation can also serve as a fuel tank in any type of ship.

According to one embodiment, the storage installation is made in the form of a floating structure, in which said supporting structure is constituted by a double hull of the floating structure. According to one embodiment, the first direction is a longitudinal direction of the floating structure.

According to one embodiment, the floating structure is a vessel for the transport of a cold liquid product, which comprises the double hull and the aforementioned tank arranged in the double hull.

According to one embodiment, the invention also provides a transfer system for a cold liquid product, the system comprising the aforementioned vessel, insulated pipes arranged so as to connect the tank installed in the hull of the vessel to a floating storage installation or land and a pump to cause a flow of cold liquid product through the insulated pipes from or to the floating or land storage facility to or from the tank of the ship.

According to one embodiment, the invention also provides a method for loading or unloading such a ship, in which a cold liquid product is conveyed through insulated pipes from or to a floating or terrestrial storage installation to or from the ship's tank.

Brief description of figures

The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation. , with reference to the accompanying drawings.

There is a schematic view of a ship with a storage facility.

There is a partial schematic sectional view of a storage facility comprising a cover according to one embodiment.

There is a partial perspective view from the inside of a ceiling wall according to one embodiment, in an area near the cover, in which only the fixing brackets and the secondary waterproofing membrane have been shown.

There is a partial perspective view of the ceiling wall of the , in an assembled state.

There is an exploded view of a stop beam, bridging plate and second abutment from the ceiling wall of the .

There is an enlarged side view of detail VI of the , representing in particular the abutment device and the stop beam.

There is an enlarged perspective view of detail VI of the , showing the attachment of a stop beam to a mounting bracket according to one embodiment.

There is a perspective view illustrating the junction of two adjacent stop beams with a bridging plate in the ceiling wall of the .

There is a partial perspective view from the inside of a ceiling wall, in an area close to the cover, showing in particular a connecting strip and a fixing support according to another embodiment.

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

By convention, we will call "on" or "above" or "upper" a position located closer to the inside of the tank and "under" or "below" or "lower" a position located closer to the load-bearing structure, regardless of the orientation of the vessel wall with respect to the earth's gravity field. Thus, Figures 3 to 9 are shown in an inverted orientation relative to their actual position in a storage facility.

There represents a 70 LNG tanker for the storage and transport of liquefied gas. However, the invention is not limited to this type of ship.

Thus, the ship 70 represented on the comprises a storage installation 1 comprising four tanks 71 arranged in the supporting structure 2 formed by the inner hull of the vessel 70 and fixed thereto. Each tank 71 is polyhedral in shape and comprises a plurality of tank walls assembled together so as to form an internal space 3, and in particular a ceiling wall 4, a rear cofferdam wall 5 and a front cofferdam wall 6 The front 6 and rear 5 cofferdam walls are spaced apart in the longitudinal direction L of the ship 70 and are fixed in the upper part to the ceiling wall 4. For the proper functioning of these tanks 71, there is provided a loading opening/ unloading 7 formed in the ceiling wall 4 in order to pass through the loading / unloading pipes. The ceiling wall 4 is fixed to an upper load-bearing wall 8 of the load-bearing structure 2. The upper load-bearing wall 8 is also provided with orifices 9 allowing the loading/unloading pipes to pass through the load-bearing structure 2.

The loading/unloading opening 7 serves as a point of entry for various LNG handling equipment, namely for example a filling line, an emergency pumping line, unloading lines linked to unloading pumps, an spray line, a supply line linked to a spray pump, etc. The operation of this equipment is known elsewhere.

There schematically represents the dihedral formed by the assembly of the ceiling wall 4 with the rear cofferdam wall 5. Indeed, the loading/unloading opening 7 is provided in the ceiling wall 4 close to the wall of the back cofferdam 5.

The multilayer structure of the ceiling wall 4 will be more particularly described below.

The multilayer structure of the ceiling wall 4 of a sealed and thermally insulating tank 71 for storing a liquefied gas, such as liquefied natural gas (LNG), comprises successively, in the thickness direction, from the outside towards the inside of the tank, a secondary thermally insulating barrier 10 retained on the upper load-bearing wall 8, a secondary sealing membrane 11 resting on the secondary thermally insulating barrier 10, a primary thermally insulating barrier 12 resting on the secondary sealing 11 and a primary sealing membrane 13 resting on the primary thermally insulating barrier 12 and intended to be in contact with the liquefied natural gas contained in the tank 71.

The secondary thermally insulating barrier 10 comprises a plurality of secondary insulating blocks 14 which are anchored to the upper load-bearing wall 8 by means of anchoring devices (not shown). The secondary insulating blocks 14 have a generally parallelepipedal shape and are for example arranged in parallel rows in the longitudinal direction L and in the transverse direction T perpendicular to the longitudinal direction L.

The secondary sealing membrane 11 of the ceiling wall 4 comprises a continuous layer of strakes 15, metal, with raised edges. The strakes 15 thus comprise a flat central portion 16 resting on the secondary insulating blocks 14 of the secondary thermally insulating barrier 10 and also comprise two raised edges 17 arranged on either side of the flat central portion 16 in the transverse direction T and projecting towards the inside of the tank with respect to the central portion 16. The strakes 15 are welded by their raised edges 17 to parallel welding supports which are fixed in grooves provided on the surface of the secondary insulating blocks 14 in contact with the secondary sealing membrane 11. The strakes 15 are, for example, made of Invar ®: that is to say an alloy of iron and nickel whose coefficient of expansion is typically between 1.2.10 ^-6 and 2.10 ^-6 K ^-1 .

The primary thermally insulating barrier 12 of the ceiling wall 4 comprises a plurality of primary insulating blocks 18 which are anchored to the upper load-bearing wall 8 by means of anchoring devices (not shown). The primary insulating blocks 18 have a generally parallelepipedal shape. In addition, they may have dimensions substantially identical to or different from those of the secondary insulating blocks 14. The primary insulating blocks 18 are positioned in alignment with the secondary insulating blocks 14, or offset from them in a or two of the longitudinal L and transverse T directions.

The secondary insulating blocks 14 and the primary insulating blocks 18 can be made in different ways. For example, all or some of them are made in the form of a box comprising a bottom plate, a cover plate and supporting webs extending, in the direction of thickness, between the bottom plate and the base plate. cover and delimiting a plurality of compartments filled with an insulating filling, such as perlite, glass or rock wool.

In another embodiment, all or some of the secondary insulating blocks 14 and primary insulating blocks 18 include a bottom plate, a cover plate, and one or more layers of insulating polymer foam sandwiched between the bottom plate, the cover plate and glued to them. The insulating polymer foam can in particular be a foam based on polyurethane, optionally reinforced with fibers.

In another embodiment, the secondary thermally insulating barrier 10 and/or the primary thermally insulating barrier 12 comprises secondary insulating blocks 14 and/or primary insulating blocks 18 having at least two different types of structure, for example the two structures mentioned above, depending on their location in the tank. Examples of such a structure are provided in publication WO-A-2019077253.

The primary sealing membrane 13 comprises a continuous sheet of metal strakes 15 with raised edges which are for example of the same nature as the strakes 15 of the secondary sealing membrane 11. The strakes 15 of the primary sealing membrane 13 are welded by their raised edges 17 on parallel welding supports which are fixed in grooves made on the surface of the primary insulating blocks 18 in contact with the primary sealing membrane 13.

The secondary 11 and primary 13 sealing membranes are fixed to the load-bearing structure 2 at the level in particular of the angle formed between the ceiling wall 4 and the rear cofferdam wall 5 using a connection ring 55 according to the known technique. The connection ring 55 is therefore fixed on the one hand to the support structure 2 and on the other hand to the sealing membranes 11, 13 in order to allow the transfer of forces between the sealing membranes 11, 13 and the structure. carrier 2.

In order to delimit the loading/unloading opening 7, the ceiling wall 4 is interrupted locally in order to allow the crossing of the loading/unloading pipes. Thus, the sealing membranes 11, 13 and the thermally insulating barriers 10, 12 are interrupted all around the loading/unloading opening 7, as represented on the .

In order to ensure continuity of sealing and insulation, the tank 71 comprises a lid 19 arranged in the loading/unloading opening 7. The lid 19 comprises a metal sealing wall 20 and a structure of thermal insulation 21 located between the metal sealing wall 20 and the upper load-bearing wall 8. The cover 19 is fixed to the upper load-bearing wall 8. The metal sealing wall 20 carries out the continuity of the seal with the membrane of primary sealing 13 of the ceiling wall 4 while the thermal insulation structure 21 achieves the continuity of the insulation.

As seen in particular in , the thermal insulation structure 21 comprises an insulating cover block 22, produced for example in the form of a box comprising a bottom plate, a cover plate and supporting webs extending, in the thickness direction, between the bottom plate and the cover plate and delimiting a plurality of compartments filled with an insulating filling, such as a rigid insulating foam. The cover insulating block 22 has passage holes (not shown) allowing the passage of the loading/unloading pipes.

The sealing wall 20 of the lid 19 comprises a plurality of flat metal plates 23 welded to each other. The sealing wall 20 further comprises a plurality of cover orifices (not shown) intended to be traversed by the loading/unloading pipes. The storage installation 1 further comprises a metal connecting strip 24 making it possible to connect the sealing wall 20 of the lid and the primary sealing membrane 13 of the ceiling wall 4 in a leaktight manner, as can be seen on the .

The primary sealing membrane 13 would be capable of transmitting to the metal connecting strip 24 compressive and tensile forces related to the work of the primary sealing membrane 13. These forces are particularly significant at the level of the longitudinal end edge front 25 of the loading/unloading opening 7, which is the edge of the loading/unloading opening 7 located between the lid 19 and the front cofferdam wall 6 in the longitudinal direction L. Indeed, due to the placement of the cover 19 close to the rear cofferdam wall 5, the longitudinal dimension of the primary sealing membrane 13 between the cover 19 and the front cofferdam wall 6 is much larger than the longitudinal dimension of the primary sealing membrane 13 between the cover 19 and the aft cofferdam wall which leads to greater forces at the level of the front longitudinal end edge 25 during the deformation of the hull or thermal contraction. In addition, these forces on the front longitudinal end edge 25 are particularly significant due to the orientation of the primary sealing membrane 13. Indeed, the primary sealing membrane 13 is oriented so that the central portion plane 16 of the strakes 15 extends in the longitudinal direction L of the vessel 70. Thus, no zone making it possible to absorb the tensile and compressive forces is provided in this direction.

In order to relieve the metal connecting strip 24, a special support structure is provided along the front longitudinal end edge 25 extending in the transverse direction T which will be detailed later.

There illustrates in particular the assembly of the secondary sealing membrane 11 at the level of the front longitudinal end edge 25 of the loading/unloading opening 7.

The storage installation 1 comprises a plurality of metal fixing supports 26 juxtaposed in the transverse direction T along the front longitudinal end edge 25 of the loading/unloading opening 7. Thus, the plurality of fixing supports 26 extends parallel to the metal connecting strip 24.

Each attachment support 26 comprises a secondary support portion 27 and a primary support portion 28 welded to the secondary support portion 27. The secondary support portion 27 has a secondary seat 29 extending in the longitudinal direction on which the primary support 28 is welded. The secondary seat 29 is welded to a secondary foot 30 which is anchored to the upper load-bearing wall 8, for example by welding. The primary support portion 28 also has a primary seat 31 extending in the longitudinal direction to which an abutment device 33, which will be described later, is welded. The primary seat 31 is welded to a primary foot 32 which is welded to the secondary seat 29. The secondary foot 30 and the primary foot 32 are, in the embodiment illustrated in , made in the form of H-section beam (sectional shape in the thickness direction). In the embodiment illustrated in , the primary foot 32 is made in the form of a circular section beam. Other cross-sectional shapes can also be used provided they offer a sufficient moment of inertia in the longitudinal direction L.

The secondary thermally insulating barrier 10 comprises secondary insulating end blocks 34. Each secondary insulating end block 34 is interposed between the secondary support portions 27 of two fixing supports 26 adjacent in the transverse direction T. A fixing plate metallic secondary 35 is fixed to the upper surface of each secondary end insulating block 34, for example by screwing or riveting, as can be seen in particular in FIGS. 3 and 4.

The secondary sealing membrane 11 comprises a row of strakes 15 in the transverse direction T interrupted by the front longitudinal end edge 25 of the opening 7. As illustrated in , these strakes 15 interrupted by the opening 7 are welded alternately to the secondary seat 29 and the secondary metal fixing plate 35 of the secondary end insulating blocks 34 according to the position of the strake 15 in the transverse direction T.

The secondary sealing membrane 11 also comprises a secondary metallic connection angle 36 extending in the transverse direction T. The secondary connection angle 36 comprises a first secondary wing 37 and a second secondary wing 38 connected to the first secondary wing 37 and forming an angle with it. The first secondary wing 37 is welded alternately to the secondary seat 29 and the secondary metal fixing plate 35 of the secondary end insulating blocks 34. The second secondary wing 38 is welded to the upper load-bearing wall 8 via an anchor plate 69 and is located between the cover 19 and the secondary support portions 27. The assembly of the strakes 15 interrupted by the opening 7, the secondary fixing plates 35, the secondary foundations 29 and the secondary connecting angles 36 make it possible to ensure a stop of the secondary sealing membrane 11 at the level of the front longitudinal end edge 25 while maintaining the continuity of the seal, in particular with respect to the cover 19.

There illustrates the ceiling wall 4 and the cover 19 at the level of the front longitudinal end edge 25 of the loading/unloading opening 7, after assembly of the primary waterproofing membrane 13.

Analogously to the secondary thermally insulating barrier 10, the primary thermally insulating barrier 12 comprises primary insulating end blocks 39. Each primary insulating end block 39 is interposed between the primary support portions 28 of two fixing supports 26 adjacent in the transverse direction T.

The primary thermally insulating barrier 12 further comprises a plurality of stop beams 40 juxtaposed in the transverse direction T. Each stop beam 40 is arranged on the primary support portions 28 of two adjacent fixing supports 26 . In addition, two stop beams 40 adjacent in the transverse direction T are jointly fixed to a primary seat 31 using a fixing device 41 illustrated in .

In addition, for assembly reasons, a bridging plate 42 is interposed between two stop beams 40 adjacent to the base of the fixing device 41, after their fixing, in order to form a continuous support surface for the membrane of primary sealing 13, as visible on the .

Provision is also made to block the translation of the stop beams 40 in the longitudinal direction. For this, the primary support portion 28 comprises an abutment device 33. The abutment device 33 comprises a first abutment 43 welded to the primary seat 31 and a second abutment 44 spaced from the first abutment 43 in the longitudinal direction L and extending in the transverse direction T, as seen in particular in . The stop beam 40 comprises a first groove 45 and a second groove 46 in a complementary manner extending in the transverse direction T. After assembly, the first stop 43 is located in the first groove 45 and is in contact with a wall of the the first groove 45 in order to block the translation of the stop beam 40 in the longitudinal direction L and in a first direction. Similarly, the second stop 44 is located in the second groove 46 and is in contact with a wall of the second groove 46 in order to block the translation of the stop beam 40 in the longitudinal direction L and in a second direction opposite to the first meaning.

To carry out the assembly, the second stop 44 is mounted only after the placement of the stop beam 40. Indeed, as shown on the , only the first stop 43 is already welded to the primary base 31 before the positioning of the stop beam 40. The second stop is illustrated in more detail on the , accompanied by the stop beam 40 and the bridging plate 42 in an exploded view.

Thus, when assembling the primary thermally insulating barrier 12 on the secondary sealing membrane 11, the stop beam 40 has a particular assembly sequence with the second stop 44 as illustrated on the . The stop beam 40 is first placed so as to position the first stop 43 in the first groove 45. The second stop 44 is at the same time inserted into the second groove 46, without being fixed to the primary seat. 31. The stop beam 40 is then pushed in the direction illustrated by the arrow F1 in order to bring the first abutment 43 into contact with a first wall of the first groove 45. The stop beam 40 is then fixed by screwing to the primary seat 31 using the fixing device 41. The fixing device 41 is for example formed of a screw/nut system provided with a clamping plate. The clamping plate makes it possible to transmit the tightening force of the screw/nut system to the two adjacent stop beams.

Then, the second stopper 44 is pushed in the direction illustrated by the arrow F2 on the in order to bring the second abutment 44 into contact with a second wall of the second groove 46. The first wall and the second wall in contact with the abutments 43, 44 face away from each other. Thus, the first abutment 43 and the second abutment 44 clamp a portion of the stop beam 40 in the longitudinal direction L, taking up all the manufacturing tolerances. It is in this position that the second abutment 44 is welded to the primary seat 31 by a weld bead 56 as illustrated in the . The first stop 43 is for example positioned on the end of the primary seat 31 closest to the cover 19, while the second stop 44 after fixing is spaced from the first stop 43 in the longitudinal direction L. Thus, the beam stop 40 is rigidly supported by the fixing brackets 26 without any residual play in the longitudinal direction L, which makes it possible to take up the tensile or compressive force that can be exerted by the primary membrane in operation, without transferring it substantially to the metal bonding strip 24. The fatigue of the metal bonding strip 24 is thus reduced and its life extended.

In the embodiment shown in , the second abutment 44 has the shape of an L-section beam which extends in the transverse direction T. The length of the second abutment 44 is here substantially equal to the distance between two mounting brackets 26 in the transverse direction T so that the second stop 44 is welded on either side to two primary seats 31 of two adjacent mounting brackets 26.

A metal primary fixing plate 47 is rigidly fixed to the upper surface of the stop beam 40, for example by screwing or riveting, as can be seen in particular in FIGS. 4 and 6. In order to maintain the flatness of the primary sealing membrane 13, the stop beam 40 has a recess 48 on its upper surface allowing the positioning of the primary fixing plate 47, as seen in Figures 5 and 6.

The primary sealing membrane 13 comprises a row of strakes 15 in the transverse direction T interrupted by the front longitudinal end edge 25 of the opening 7. As illustrated in , the end portions of these strakes 15 interrupted by the opening 7 are welded to the primary fixing plates 47 in the transverse direction T.

The primary waterproofing membrane 13 also comprises a metal primary connecting angle 49 extending in the transverse direction T. The primary connecting angle 49 comprises a first primary wing 50 and a second primary wing 51 connected to the first primary wing 50 and forming an angle with it. The first primary wing 50 is welded to the primary fixing plate 47. The second primary wing 51 is welded to the second secondary wing 38 of the secondary connecting angle 36 and is located between the cover 19 and the primary support portions 28. The assembly of the strakes 15 interrupted by the opening 7 of the primary sealing membrane 13, the primary fixing plates 47, and the primary connection angles 49 make it possible to ensure the continuity of the seal on the beam of stop 40, in particular with respect to the cover 19.

Finally, the metal connecting strip 24 is welded in the transverse direction T on the one hand to the flat plates 23 of the sealing wall 20 of the cover 19 and on the other hand to the primary connecting angle 49 and/or to the primary fixing plate 47, allowing sealing between the primary sealing membrane 13 of the ceiling wall 4 and the sealing wall 20 of the cover 19.

As seen on the , the metal connecting strip 24 may further comprise a corrugation 54 extending in the transverse direction T in order to elastically absorb the deformations resulting from the residual compression and tensile forces in the longitudinal direction L, and thus limit the stresses in the welds. There shows another embodiment in which the connecting strip 24 comprises two parallel undulations 54. The corrugation or corrugations are located in the central part of the metal connecting strip 24, at a distance from the welds located along the edges parallel to the transverse direction T.

As shown on the , support plates 52, for example made of plywood, are positioned on either side of the second primary 51 and secondary 38 wings of the angles in order to stiffen them. A support plate 52 is also positioned above the space between the cover 19 and the connecting angles 26, 49 in order to support the metal connecting strip 24. This space is filled with insulating packing 53, by example of glass wool blocks.

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

In a manner known per se, loading/unloading pipes 73 arranged on the upper deck of the ship can be connected, by means of appropriate connectors, to a maritime or port terminal to transfer a cargo of LNG from or to the tank 71.

There represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipeline 76 and an installation on land 77. The loading and unloading station 75 is a fixed off-shore installation comprising a mobile arm 74 and a tower 78 which supports the mobile arm 74. The mobile arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading/unloading pipes 73. The orientable mobile arm 74 adapts to all sizes of LNG carriers. A connecting pipe, not shown, extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the shore installation 77. This comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the underwater pipe 76 to the loading or unloading station 75. The underwater pipe 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the installation on land 77 over a great distance, for example 5 km, which makes it possible to keep the LNG carrier 70 at a great distance from the coast during loading and unloading operations.

To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and/or pumps fitted to the shore installation 77 and/or pumps fitted to the loading and unloading station 75 are used.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

The use of the verb "to comprise", "to understand" or "to include" and of its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

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

Claims (20)

Storage installation (1) for liquefied gas comprising a metal support structure (2) and a sealed and thermally insulating tank (71) arranged in the support structure,
the tank comprising at least one metal sealing membrane (11, 13) defining an internal storage space (3) and at least one thermally insulating barrier (10, 12), the thermally insulating barrier being placed between the sealing membrane and the supporting structure,
the load-bearing structure comprising an upper load-bearing wall (8),
the tank (71) comprising at least one ceiling wall (4) fixed to the upper load-bearing wall (8),
in which the thermally insulating barrier (10, 12) of the ceiling wall comprises juxtaposed insulating blocks (14, 18),
wherein the sealing membrane (11, 13) of the ceiling wall (4) comprises a plurality of parallel strakes (15) extending in a first direction (L), each strake (15) comprising a planar central portion (16) resting on an upper surface of the insulating blocks (14, 18) and two raised edges (17) projecting towards the inside of the tank with respect to the central portion (16), the strakes (15) being juxtaposed in a second direction (T) in a repeated pattern and sealingly welded together at the raised edges, the second direction being perpendicular to the first direction, anchor wings anchored to the insulating blocks (14, 18) and parallel to the first direction being arranged between the juxtaposed strakes to retain the sealing membrane (11, 13) on the thermally insulating barrier (10, 12),
the ceiling wall (4) being interrupted locally so as to delimit a loading/unloading opening (7) intended to be traversed by loading/unloading pipes, said loading/unloading opening (7) interrupting at least one said strake (15),
wherein the tank has a lid (19) disposed in the loading/unloading opening (7), the lid (19) comprising a metal sealing wall (20) and a thermal insulation structure (21) located between the sealing wall (20) and the upper load-bearing wall (8), the cover (19) being fixed to the upper load-bearing wall (8),
wherein the insulating blocks have an end insulating block (35, 39) adjacent to the cover (19) in the first direction,
in which the storage installation comprises a fixing support (26) fixed to the upper load-bearing wall (8) in line with the end insulating block (34, 39), the fixing support (26) having a length of seat extending in the first direction, the thermally insulating barrier comprising a stop beam (40) arranged on the fixing support (26), the fixing support (26) comprising a stop device (33) blocking the translation of the stop beam (40) in the first direction,
wherein a metal fixing plate (47) is fixed to the stop beam (40), an end portion of the or each strake (15) interrupted by the loading/unloading opening (7) being welded to the metal fixing plate (47),
and wherein a metal connection strip (24) connects the sealing wall (20) of the cover (19) to the metal fixing plate (47) to ensure the continuity of the sealing membrane of the ceiling wall ( 4). Storage facility (1) according to claim 1, wherein the storage facility (1) comprises a plurality of fixing brackets (26) juxtaposed in the second direction along one edge of the loading/unloading opening (7), two adjacent mounting brackets (26) being separated from each other by at least one end insulating block (34, 39). Storage facility (1) according to claim 2, wherein the stop beam (40) has a length extending in the second direction over at least two adjacent fixing brackets and a width extending in the first direction. Storage installation (1) according to Claim 3, in which the thermally insulating barrier comprises a plurality of stop beams (40) juxtaposed in the second direction, each stop beam (40) being arranged on two fixing supports ( 26) adjacent. Storage installation (1) according to one of Claims 1 to 4, in which the sealing membrane (13) comprises a connection angle (49) extending in the second direction for sealingly separating the thermally insulating barrier (10, 12) of the thermal insulation structure (21) of the cover, the connecting angle (49) comprising a first wing (50) and a second wing (51) connected to the first wing, the first wing (50 ) being welded to the fixing plate (47) and the second wing (51) being connected to the upper load-bearing wall (8). Storage installation (1) according to one of Claims 1 to 5, in which the connecting strip (24) has a corrugation (54) extending in the second direction. Storage installation (1) according to one of Claims 1 to 6, in which the stop beam (40) has a first groove (45) extending in the second direction, and a second groove (46) extending extending in the second direction, the abutment device (33) comprising a first abutment (43) located in the first groove (45) and being in contact with a wall of the first groove (45), the first abutment (43) blocking the translation of the stop beam (40) in the first direction and in a first direction, the abutment device (33) comprising a second abutment (44) located in the second groove (46) and being in contact with a wall of the second groove (46), the second stop (44) blocking the translation of the stop beam (40) in the first direction and in a second direction opposite to the first direction. Storage installation (1) according to one of Claims 1 to 7, in which the abutment device (33) is arranged directly above the fixing plate (47). Storage installation (1) according to one of Claims 1 to 8, in which the sealing membrane (13), the sealing wall (20) of the lid and the connecting strip (24) are made of an alloy of iron and nickel having a coefficient of thermal expansion of between 0.5×10 ^-6 and 2×10 ^-6 K ^-1 . Storage installation (1) according to one of Claims 1 to 9, in which the fixing support (26) is made of steel and the stop beam (40) is made of plywood. Storage installation (1) according to one of Claims 1 to 10, in which the supporting structure comprises a rear cofferdam wall (5) and a front cofferdam wall (6) located on either side of the tank in the first direction, the loading/unloading opening being formed close to the rear cofferdam wall (5), the end insulating block (39) and the fixing bracket being arranged between the cover (19) and the wall front cofferdam (6). Storage installation (1) according to one of Claims 1 to 11, in which the sealing membrane is a primary sealing membrane (13) intended to be in contact with the liquefied gas, the thermally insulating barrier is a primary thermally insulating barrier (12) and in which the vessel further comprises, in a direction of thickness from the outside towards the interior of the vessel, a secondary thermally insulating barrier (10) fixed to the load-bearing structure (2), and a metallic secondary sealing membrane (11) placed between the secondary thermally insulating barrier (10) and the primary thermally insulating barrier (12). Storage facility (1) according to claim 12, in which the connection angle is a primary connection angle (49), the secondary sealing membrane (11) comprises a secondary connection angle (36) for sealingly separating the secondary thermally insulating barrier of the thermally insulating structure of the lid, the secondary connecting angle comprising a first flange (37) and a second flange (38) connected to the first flange, the first flange (37) of the secondary connection being welded to the secondary sealing membrane (11) and the second wing (38) of the secondary connection angle being welded to the upper load-bearing wall (8). Storage installation (1) according to claim 13, in which the second leg (51) of the primary connection angle is welded to the second leg (38) of the secondary connection angle. Storage installation (1) according to one of Claims 12 to 14, in which the fixing support (26) comprises a secondary support portion (27) welded to the upper load-bearing wall (8) and a primary support portion ( 28) welded to the secondary support portion (27), the stop beam (40) being disposed on the primary support portion (28), the secondary sealing membrane (11) being welded to the secondary support portion (27). A storage facility (1) according to claim 15, wherein a dimension of the primary support portion (28) in the first direction is less than a dimension of the stop beam (40) in the first direction. Storage installation (1) according to one of Claims 1 to 16, made in the form of a floating structure, in which the said supporting structure consists of a double hull (72) of the floating structure and in which the first direction is a longitudinal direction (L) of the floating structure. Storage installation (1) according to claim 17, in which the floating structure is a vessel (70) for transporting a cold liquid product. Transfer system for a cold liquid product, the system comprising a storage installation according to claim 18, insulated pipes (73, 79, 76, 81) arranged so as to connect the tank (71) installed in the hull of the ship to an external floating or land storage facility (77) and a pump for driving a flow of cold liquid product through the insulated pipes from or to the external floating or land storage facility to or from the ship's tank. Method of loading or unloading a storage installation according to claim 18, in which a cold liquid product is conveyed through insulated pipes (73, 79, 76, 81) from or to an external floating or terrestrial storage installation (77 ) to or from the vessel's tank (71).