Facility for storing a liquefied gas

Abstract

The invention relates to a facility for storing a liquefied gas, the tank comprising a horizontal first tank wall (1) and an inclined second tank wall (2), wherein each of the first and second tank walls comprises at least one sealing membrane (7) comprising a plurality of strakes (11), wherein the tank wall comprises a metal connection beam (13) comprising: - a hollow central core (17), - a first connection flange (28) being attached to the sealing membrane (7) of the first tank wall (1), - a second connection flange (29) being attached to the sealing membrane (7) of the second tank wall (2), - a first anchoring flange (33) being attached to the second supporting wall (5), and - a second anchoring flange (32) being attached to the first supporting wall (4), wherein the supporting structure comprises at least one beam stiffener (43) which is substantially aligned in the first direction (D1) with the first anchoring flange (33) and the first connection flange (28).

Description

LIQUEFIED GAS STORAGE FACILITY

[0001] The invention relates to the field of leak-proof and thermally insulated membrane tanks. In particular, the invention relates to the field of leak-proof and thermally insulated tanks for the storage and / or transport of liquefied gases at low temperatures, such as tanks for transporting Liquefied Petroleum Gas (LPG) at temperatures ranging, for example, from -50°C to 0°C, or for transporting Liquefied Natural Gas (LNG) at approximately -162°C at atmospheric pressure. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank can be used for transporting liquefied gas or for receiving liquefied gas to serve as fuel for the propulsion of the floating structure. Technological background

[0002] Document FR3102138 is known to describe liquefied gas storage facilities comprising a load-bearing structure and a sealed and thermally insulated tank supported by the load-bearing structure.

[0003] The tank in this document includes, in particular, a watertight membrane which has a plurality of strakes, each having a flat central portion resting on an upper surface of the insulating barrier and two raised edges projecting inwards from the flat central portion of the tank, the strakes being juxtaposed and welded together in a watertight manner at the raised edges.

[0004] This watertight membrane is anchored to the supporting structure by means of a connecting beam at an edge formed between two tank walls. The connecting beam also serves to create a watertight seal between the strakes of the first wall and the strakes of the second wall.

[0005] Events such as temperature changes or the deflection of the ship's beam when the storage facility is located on a vessel impose significant stresses on the waterproof membrane, which are transmitted to the supporting structure via the connecting beam. These stresses are particularly pronounced at connections of the waterproof membrane to a horizontal wall along the ship's strakes. The coefficient of thermal expansion of the material used for the waterproof membrane also directly influences the value of these stresses.

[0006] One idea behind the invention is to improve the mechanical strength at the corners of a storage installation.

[0007] According to one embodiment, the invention provides a liquefied gas storage installation comprising a load-bearing structure and a sealed and thermally insulated tank supported by the load-bearing structure, the tank having a first horizontal tank wall fixed to a first horizontal load-bearing wall and a second inclined tank wall fixed to a second inclined load-bearing wall joining the first horizontal load-bearing wall at an edge of the load-bearing structure, the edge extending along an edge direction, each of the first and second load-bearing walls having an internal surface and an external surface, the first load-bearing wall extending in a plane formed by the edge direction and a first direction, the second load-bearing wall extending in a plane formed by the edge direction and a second direction, the first and second directions being perpendicular to the edge direction.the first direction and the second direction being inclined at a tank angle wherein each of the first and second tank walls comprises at least one watertight membrane and a thermally insulating barrier arranged between the watertight membrane and the load-bearing wall, wherein the watertight membrane comprises a plurality of strakes each comprising at least one flat portion resting on an upper surface of the insulating barrier and at least one projecting portion protruding into the interior of the tank relative to the flat portion, the strakes being juxtaposed and welded together watertight at the edges, the strakes of the first tank wall extending in the first direction, wherein the tank wall comprises a metal connecting beam arranged parallel to the edge direction and anchored to the internal surface of the first and second load-bearing walls, the connecting beam comprising: - a central core,- a first connecting wing protruding from the central core and being fixed to the watertight membrane of the first tank wall, - a second connecting wing protruding from the central core and being fixed to the watertight membrane of the second tank wall, - a first anchoring wing protruding from the central core and being aligned with the first connecting wing in the first direction, the first anchoring wing being fixed to the second load-bearing wall by means of a first connecting strip, the first anchoring wing and the first connecting wing being located on either side of the central core, and - a second anchoring wing protruding from the central core and being aligned with the second connecting wing and being fixed to the first load-bearing wall by means of a second connecting strip, the second anchoring wing and the second connecting wing being located on either side of the central core,in which the load-bearing structure comprises a plurality of stiffeners projecting perpendicularly from the external surface of the second load-bearing wall, the plurality of stiffeners comprising at least one beam stiffener extending parallel to the edge direction, the beam stiffener being substantially aligned in the first direction with the first anchor flange and the first connecting flange.

[0008] Thanks to these characteristics, the beam stiffener allows the load-bearing wall to be reinforced at the point where the horizontal tank wall's watertight membrane is anchored, in the direction of the strakes. Indeed, strake membranes are commonly called "tensioned" membranes because they do not have deformable bellows in the main direction of the strakes to absorb thermal contraction / expansion. Therefore, thanks to the beam stiffener, the load-bearing structure can withstand greater stresses without deforming at the point where the horizontal tank wall's watertight membrane exerts maximum force.

[0009] The expression "approximately aligned" here means that alignment must be taken into account with the assembly and manufacturing tolerances of the various elements which may result in a slight alignment deviation of a few centimeters on installations several meters high.

[0010] Depending on the embodiment, such an installation may include one or more of the following characteristics.

[0011] According to one embodiment, a distance in the second direction between the beam stiffener and the first anchor flange is less than 50 mm, preferably less than 40 mm.

[0012] According to one embodiment, the beam stiffener has a width in the first direction of between 300 and 600 mm, for example 400 mm.

[0013] According to one embodiment, the beam stiffener comprises a distal end of the second load-bearing wall, the distal end having a T-shaped or L-shaped cross-section.

[0014] According to one embodiment, the first and second connecting strips have a thickness greater than the thickness of the first and second anchoring wings and / or greater than the thickness of the first and second connecting wings.

[0015] According to one embodiment, the thickness of the first and second anchoring wings is identical to the thickness of the first and second connecting wings, for example on the order of 1.5 mm.

[0016] According to one embodiment, the strakes comprise main strakes and end strakes, the end strakes connecting the main strakes to the connecting beam.

[0017] According to one embodiment, the main strakes have a thickness less than the thickness of the first and second anchor wings and / or greater than the thickness of the first and second connecting wings, the thickness of the main strakes being for example on the order of 0.7 mm.

[0018] According to one embodiment, the thickness of the end strakes is, for example, on the order of 1.5 mm.

[0019] According to one embodiment, the thickness of the first and second connecting strips is, for example, around 2.5 mm.

[0020] According to one embodiment, the strakes are made of an alloy whose coefficient of thermal expansion is less than 10.10 -6 K -1 .

[0021] According to one embodiment, the strakes are made of an alloy whose coefficient of thermal expansion is greater than 6.10 -6 K -1 .

[0022] According to one embodiment, the strakes are made of an iron alloy with a high manganese content.

[0023] According to one embodiment, the high manganese iron alloy comprises between 24 and 34% Mg by weight.

[0024] According to one embodiment, the high-manganese iron alloy has a coefficient of thermal expansion between 6 and 10.10 -6 K -1, for example, in the order of 7.10 -6 K -1 .

[0025] According to one embodiment, the strakes are made of an alloy whose coefficient of thermal expansion is between 0.5 and 2.10 -6 K -1 .

[0026] According to one embodiment, the strakes are made of an iron and nickel alloy, for example Invar®.

[0027] According to one embodiment, at least one flat portion is a central flat portion resting on an upper surface of the thermally insulating barrier and the strakes have two projecting portions made in the form of two raised edges projecting towards the inside of the tank relative to the central flat portion.

[0028] According to one embodiment, the strakes comprise at least two flat portions resting on an upper surface of the insulating barrier and at least one corrugation projecting towards the interior of the tank relative to the flat portions, the flat portions being on either side of at least one corrugation.

[0029] According to one embodiment, the connecting beam is made of an iron and nickel alloy with a coefficient of expansion between 0.5 x 10 -6 and 2.10 -6 K -1 .

[0030] According to one embodiment, the load-bearing structure includes anchor plates extending in the edge direction and projecting from the inner surface of the first and second load-bearing walls, the first connecting strip being fixed to one of the anchor plates of the second load-bearing wall, and the second connecting strip being fixed to one of the anchor plates of the first load-bearing wall.

[0031] According to one embodiment, the anchor plates have a thickness of between 8 and 12 mm.

[0032] According to the embodiment, the tank comprises two watertight membranes and two thermally insulating barriers, the two watertight membranes being fixed to the connecting beam.

[0033] According to one embodiment, the central core of the connecting beam is hollow.

[0034] According to one embodiment, the beam stiffener has a thickness of between 10 and 20 mm.

[0035] According to one embodiment, the plurality of stiffeners comprises a network of primary stiffeners and a network of secondary stiffeners, the primary stiffeners having a dimension in the first direction greater than the secondary stiffeners, the network of secondary stiffeners comprising the beam stiffener.

[0036] According to one embodiment, the primary stiffener network comprises second primary stiffeners parallel to the second direction and primary edge stiffeners parallel to the edge direction, and the secondary stiffener network comprises second secondary stiffeners parallel to the second direction and secondary edge stiffeners parallel to the edge direction, the secondary edge stiffeners including the beam stiffener.

[0037] Such a facility can be a land-based storage facility, for example for storing LNG, or a floating structure, coastal or deep-water, including an LNG carrier, a floating storage and regasification unit (FSRU), a floating production and storage unit (FPSO), and others. Such a facility can also serve as a fuel tank on any type of ship.

[0038] According to one embodiment, a ship for the transport of a cold liquid product comprises a double hull and the aforementioned storage facility, the double hull comprising the load-bearing structure of the storage facility.

[0039] 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 to connect the vessel's tank to a floating or land-based storage facility, and a pump to drive a flow of cold liquid product through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

[0040] According to one embodiment, the invention also provides a method for loading or unloading a ship, in which a cold liquid product is conveyed through insulated pipes from or to a floating or land-based storage facility to or from the tank of the aforementioned ship. Brief description of the figures

[0041] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation, with reference to the accompanying drawings.

[0042] Larepresents a partial cutaway perspective view of a sealed and thermally insulating tank at the level of a junction between two walls.

[0043] Lare represents a partial perspective view of a connecting beam positioned at the edge of a tank according to an embodiment.

[0044] Larepresents in perspective view from inside the storage facility a connecting beam and the load-bearing structure according to an embodiment.

[0045] Larepresents in perspective, viewed from outside the storage facility, a connecting beam and the load-bearing structure according to an embodiment.

[0046] This view of detail V represents more particularly the arrangement of the beam stiffener in relation to the connecting beam.

[0047] This is a schematic cutaway representation of a methane tanker including a ship tank and a terminal for loading / unloading this tank.

[0048] By convention, a position closer to the inside of the tank will be called "on" or "above," and a position closer to the supporting structure will be called "under" or "below," regardless of the tank wall's orientation relative to Earth's gravity. Similarly, an element closer to the inside of the tank will be called "upper" or "internal," and an element closer to the supporting structure will be called "lower" or "external."

[0049] A sealed and thermally insulated tank 71 will be described later, and in particular a connecting beam for such a tank 71.

[0050] Tank 71, integrated into a ship's hull for example, has a polyhedral shape. For example, tank 71 may include a bottom wall, a ceiling wall, a forward cofferdam wall, a rear cofferdam wall, two transverse walls, and possibly lower and / or upper chamfer walls.

[0051] The general structure of such a tank 71 is well known. We will therefore only describe one wall area of ​​the tank, it being understood that all the walls of the tank may have a similar general structure.

[0052] In relation to this, we now describe the multilayer structure of a tank wall, in this example a horizontal tank wall 1 (the bottom or ceiling wall) according to one embodiment. The horizontal tank wall 1 comprises, in the direction of the tank thickness, from the outside to the inside, a secondary thermally insulating barrier 6 resting against a load-bearing wall 5, a secondary airtight membrane 7, a primary thermally insulating barrier 8, and a primary airtight membrane 9 intended to be in contact with the liquefied gas stored in the tank.

[0053] The primary thermal insulation barrier 8 and the secondary thermal insulation barrier 6 are each made up of insulating elements, for example, parallelepiped-shaped insulating panels 10 arranged in a regular pattern. Various techniques are known for manufacturing such thermal insulation elements. For example, each insulating panel 10 is formed as described in publication FR2877638. Each insulating panel 10 is held to the load-bearing wall 5 by means of anchoring devices, which can be made in numerous ways according to known techniques, for example, as described in publication FR2973098. The insulating panels 10 of the primary thermal insulation barrier 8 and the secondary thermal insulation barrier 6 support the primary membrane 9 and the secondary membrane 7, respectively.

[0054] In another, unillustrated embodiment, the primary thermally insulating barrier 8 and the secondary thermally insulating barrier 6 may comprise a plurality of insulating panels that are anchored to the supporting structure by means of anchoring devices, such as those described, for example, in document WO2014096600. The insulating panels are generally parallelepiped in shape and are arranged in parallel rows. Each insulating panel comprises a base plate, optionally an intermediate plate, and a cover plate that defines a support surface for the waterproof membrane. The plates are, for example, made of plywood. Each insulating panel also comprises one or more layers of insulating polymer foam sandwiched between the plates. The insulating polymer foam may, in particular, be a polyurethane-based foam, optionally reinforced with fibers.The cover plate may have parallel grooves. The grooves have a shape roughly resembling an inverted T to accommodate a wing of the welding supports.

[0055] The secondary membrane 7 and primary membrane 9 are, for example, made of a series of parallel metal plates called struts 11 with folded edges, which are arranged alternately with elongated weld supports 12. The struts 11 and weld supports 12 are made of an alloy with a low coefficient of expansion. The struts 11 and weld supports 12 are, for example, made of a high-manganese iron alloy with a coefficient of expansion typically on the order of 7.10 -6 K -1 . The membranes, secondary 7 and primary 9, typically have a thickness between 0.5 and 1.5 mm, and preferably 0.7 mm.

[0056] In another embodiment not shown, the primary membrane 9 is made using corrugated stainless steel metal plates welded together.

[0057] In another embodiment not shown, the secondary membrane 7 and / or the primary membrane 9 may have strakes, each comprising at least two flat portions resting on an upper surface of the thermally insulating barrier and at least one corrugation projecting inwards towards the tank relative to the flat portions, the flat portions being located on either side of a corrugation. The strakes are juxtaposed and welded together watertight at the edges, for example by lap welding.

[0058] The strakes 11 have, in their widthwise direction, a flat central band resting against the insulating panels 10 and raised lateral edges. The raised edges extend substantially perpendicularly to the flat central band. The raised edges of the strakes 11 are welded watertight to the weld supports 12. Further details on the construction of such a membrane can be found in publication FR2968284.

[0059] We now describe in more detail a corner zone of the storage installation. This is a perspective view of an edge zone between a horizontal tank wall 1 and a tank wall inclined 2 relative to the horizontal tank wall 1, in this example with an inclination of 90°. The horizontal tank wall 1 extends in a plane formed by an edge direction A and a first direction D1. The inclined tank wall 2 extends in a plane formed by the edge direction A and a second direction D2. The first direction D1 and the second direction D2 are perpendicular to the edge direction A. The first direction D1 and the second direction D2 are inclined to each other here at an angle of 90°. This angle could be different depending on the position within the tank, for example, 135°.

[0060] In the case represented in, the strakes 11 of the horizontal tank wall 1 extend along the first direction D1 while the strakes of the inclined tank wall 2 extend along the edge direction A.

[0061] At this zone, the horizontal load-bearing wall 4 of the horizontal tank wall 1 and the inclined load-bearing wall 5 of the inclined tank wall 2 meet at an edge 3 extending along the edge direction A. The membranes, secondary 7 and primary 9 of the two tank walls 1, 2 are connected by an anchoring device allowing the secondary 7 and primary 9 waterproof membranes to be anchored on one side to the load-bearing wall 4 of the horizontal tank wall 1 and on the other side to the load-bearing wall 5 of the inclined tank wall 2.

[0062] More specifically, the secondary membranes 7 and primary membranes 9 of the horizontal tank wall 1 are anchored to the load-bearing wall 5 of the inclined tank wall 2. Similarly, the secondary membranes 7 and primary membranes 9 of the inclined tank wall 2 are anchored to the load-bearing wall 4 of the horizontal tank wall 1.

[0063] The anchoring device allows the tensile forces resulting from the thermal contraction of the secondary membranes 7 and primary membranes 9 to be absorbed. The anchoring device also allows the forces resulting from the deformation of the hull and in particular from the bending of the longitudinal wall of a ship corresponding to the beam effect of the ship.

[0064] The anchoring device consists of an elongated connecting beam 13 extending along the edge direction A. The connecting beam 13 has at least a first section 14 and a second section 15 aligned with each other in the direction of the edge 3 and defining at the junction between the two sections 14, 15 an assembly window 16.

[0065] Each section 14, 15 comprises a hollow central core 17 with a parallelogram cross-section, here rectangular since, in the example illustrated in Figures 4, the two load-bearing walls 4, 5 form a right angle. Like the waterproof membranes, the connecting beam 13 can be made of an alloy with a low coefficient of expansion, for example, with sheets of metal with a thickness between 1 and 3 mm, for example 1.5 mm. In one embodiment, the connecting beam 13 is made of Invar®, i.e., an iron-nickel alloy with a coefficient of expansion typically between 0.5 and 10⁻³. -6 and 2.10 -6 K -1 .

[0066] To hold the connecting beam 13 on each side of the edge 3, each of the load-bearing walls 5 has a primary anchor plate 18 and a secondary anchor plate 19. The distance from the secondary anchor plates 19 to the edge 3 corresponds to the thickness of the secondary thermally insulating barrier 6. The distance between the anchor plates 18 and 19 corresponds to the thickness of the primary thermally insulating barrier 8. The anchor wings 32-35 are fixed to the anchor plates 18, 19 by means of a connecting strip 45.

[0067] As more clearly seen on the diagram, the connecting beam 13 is made of flat metal sheets welded together to form: - a hollow central core 17 having a rectangular or square section (in the case of a right-angled edge zone) whose side length is equal to the distance between the primary anchor plate 18 and the secondary anchor plate 19 of the load-bearing wall to which each side is parallel, the hollow central core comprising a first core wall 20 and a second core wall 21 connected to the first core wall 20 along a first edge 24 of the central core 17, a third core wall 22 connected to the first core wall 20 at the level of a second edge 25, and a fourth core wall 23 connected to the second core wall 21 at the level of a third edge 26, the fourth core wall 23 being connected to the third core wall 22 at the level of a fourth edge 27;- connecting wings 28, 29, 30, 31 projecting outwards from the central core towards the primary 9 and secondary 7 sealing membranes of the first and second tank walls 1, 2, the connecting wings 28, 29, 30, 31 allowing the secondary sealing membranes 7 of the tank walls 1, 2 to be connected in a watertight manner as well as the primary sealing membranes 9 of the tank walls 1, 2; - anchoring wings 32, 33, 34, 35 projecting outwards from the central core 17 towards the load-bearing walls 5 of the tank walls 1, 2, the anchoring wings being fixed to the load-bearing walls 5.;

[0068] The first core walls 20 of the first and second sections 14, 15 are parallel and define at the junction between the two sections 14, 15 a part of the assembly window 16, and the second core walls 21 of the first and second sections 14, 15 are parallel and define at the junction between the two sections 14, 15 another part of the assembly window 16.

[0069] The connecting wings comprise: - a first secondary connecting wing 28 connected to the first edge 24 of the central core 17 and located in a plane parallel to the secondary waterproof membrane 7 of the first tank wall 1, the first secondary connecting wing 28 being welded watertight to the secondary waterproof membrane 7 of the first tank wall 1, - a second secondary connecting wing 29 connected to the second edge 25 of the central core 17 and located in a plane parallel to the secondary waterproof membrane 7 of the second tank wall 2, the second secondary connecting wing 29 being welded watertight to the secondary waterproof membrane 7 of the second tank wall 2, - a first primary connecting wing 30 connected to the third edge 26 of the central core 17 and located in a plane parallel to the primary waterproof membrane 9 of the first tank wall 1.the first primary connecting wing 30 being hermetically welded to the primary sealing membrane 9 of the first tank wall 1,- a second primary connecting wing 31 connected to the third edge 26 of the central core 17 and being located in a plane parallel to the primary sealing membrane 9 of the second tank wall 2, the second primary connecting wing 31 being hermetically welded to the primary sealing membrane 9 of the second tank wall 2.,

[0070] The anchoring wings comprise: - a first secondary anchoring wing 32 connected to the fourth edge 27 of the central core 17 and located in the same plane as the second secondary connecting wing 29, the first secondary anchoring wing 32 being fixed to the secondary anchoring plate 18 of the first tank wall 1, - a second secondary anchoring wing 33 connected to the fourth edge 27 of the central core 17 and located in the same plane as the first secondary connecting wing 28, the second secondary anchoring wing 33 being fixed to the secondary anchoring plate 18 of the second tank wall 2, - a first primary anchoring wing 34 connected to the third edge 26 of the central core 17 and located in the same plane as the second primary connecting wing 31, the first primary anchoring wing 34 being fixed to the primary anchoring plate 19 of the first tank wall 1.- a second primary anchoring wing 35 connected to the second edge 25 of the central core 17 and located in the same plane as the first primary connecting wing 30, the second primary anchoring wing 35 being fixed to the primary anchoring plate 19 of the second tank wall 2.,

[0071] In order to ensure the continuity of the insulation at the level of the central hollow core 17, insulating elements 36 are positioned inside the central hollow core 17 and between the anchoring wings 32-35 to form the secondary thermally insulating barrier 6 and the primary thermally insulating barrier 8 at the edge 3. The insulating elements 36 can be in the form of boxes filled with insulating materials such as glass wool or perlite or insulating foam blocks for example.

[0072] As described previously and visible in particular on the figure, the connecting beam 13 has an assembly window 16 at the junction between two adjacent sections 14, 15. The assembly window 16 is formed by cutouts in the first core wall 20 and in the second core wall 21. This assembly window 16 allows in particular to be welded in a watertight manner using a metal joint 37 the third core wall 22 of the first section 14 to the third core wall 22 of the second section 15, the fourth core wall 23 of the first section 14 to the fourth core wall 23 of the second section 15 as well as the secondary connecting flanges 28, 29 of the first section 14 to those of the second section 15.Indeed, the third core wall 22, the fourth core wall 23 and the secondary connecting wings 28, 29 allow the continuity of the secondary waterproof membrane 7 between the first tank wall 1 and the second tank wall 2 at the level of the connecting beam 13. In addition, the insertion of the insulating elements 36 inside the hollow central core 17 is carried out prior to the closing of the assembly window 16.

[0073] The connecting beam 13 includes a connecting assembly 38, complementary in shape to the assembly window 16, and fixed at said assembly window 16 to the first section 14 and the second section 15. The insulating elements 36 are thus placed in the hollow central core 17 before the connecting assembly 38 is fixed at the assembly windows 16a, 16b, since the connecting assembly 38 closes said windows 16a, 16b. The connecting assembly 37 is, for example, described in document FR3102138.

[0074] The continuity of the primary sealing membrane 9 between the first tank wall 1 and the second tank wall 2 is achieved by the primary connecting wings 30, 31.

[0075] Figures 3 to 5 illustrate more particularly the design of the inclined load-bearing wall 5 at the level of the connecting beam 13. That is why in these figures in tank 71, only the connecting beam 13 and the connections between the connecting beam 13 and the inclined load-bearing wall 5 have been illustrated.

[0076] In order to support all the stresses exerted on the supporting structure, for example the hydrostatic pressure of the tank container or other stresses exerted by the internal elements of the tank, the load-bearing walls 4, 5 of the supporting structure have stiffeners projecting perpendicularly to an external surface of each load-bearing wall 4, 5. Subsequently, only the stiffeners of the inclined load-bearing wall 5 will be described in more particular detail.

[0077] As can be seen in particular on the figure, the inclined load-bearing wall 5 first comprises a network of primary stiffeners 39. The primary stiffeners 39 include second primary stiffeners parallel to the second direction D2 and primary edge stiffeners parallel to the edge direction A. The second primary stiffeners cross the primary edge stiffeners throughout the inclined load-bearing wall 5 so as to form the network of primary stiffeners 39. The primary stiffeners 39 have a width in the first direction D1 on the order of several meters, for example between 2 and 5 m.

[0078] The inclined load-bearing wall 5 also includes a network of secondary stiffeners 40. The secondary stiffeners 40 include second secondary stiffeners 41 parallel to the second direction D2 and secondary edge stiffeners 42 parallel to the edge direction A. The secondary stiffeners 40 have a width in the first direction D1 of the order of several tens of centimeters, for example between 20 and 60 cm.

[0079] The invention relates more particularly to one of the secondary edge stiffeners 42, namely the beam stiffener 43.

[0080] Strapped membranes are commonly called "stretched" membranes because they do not have deformable bellows straps in the main direction to absorb thermal contraction / expansion. However, the secondary watertight membrane 7 of the horizontal tank wall 1 has straps 11 that extend in the first direction D1, which, when the tank 71 is loaded onto a vessel 70, corresponds to the longitudinal direction of the vessel 70. Furthermore, the fact that here the secondary membrane 7 is made of an iron-manganese alloy, which has a higher coefficient of thermal expansion than the material usually used (namely, an iron-nickel alloy), further increases these stresses.

[0081] This secondary waterproof membrane 7 is anchored to the secondary anchor plate 19 of the inclined load-bearing wall 5 via the connecting wing 28, the fourth core wall 24, the anchor wing 33, and a connecting strip 45. It is therefore at the secondary anchor plate 19 and in the alignment of the connecting wing 28, the fourth core wall 24, the anchor wing 33, and the connecting strip 45 that the stresses exerted on the inclined load-bearing wall 5 by the secondary waterproof membrane 7 are the greatest.

[0082] The beam stiffener 43 thus extends parallel to the edge direction A and is substantially aligned in the first direction D1 with the anchor flange 33 and the connecting strip 45, as shown in particular in Figure 1. Ideally, the beam stiffener 43 is aligned in the first direction D1 with these elements. However, due to the assembly and manufacturing tolerances of the various components of the installation, a slight misalignment is acceptable. Thus, a distance in the second direction D2 between the beam stiffener 43 and the anchor flange 33 is advantageously less than 50 mm, and preferably less than 40 mm.

[0083] In another embodiment not shown, the installation includes a second beam stiffener 43 extending parallel to the edge direction A and being substantially aligned in the first direction D1 with the anchor flange 35 and the connecting flange 30 so as to be substantially aligned with the primary waterproof membrane 9. Ideally, the second beam stiffener is aligned in the first direction D1 with these elements. However, due to the assembly and manufacturing tolerances of the various components of the installation, a slight misalignment is acceptable. Thus, a distance in the second direction D2 between the second beam stiffener 43 and the anchor flange 35 is advantageously less than 50 mm, and preferably less than 40 mm.

[0084] As can be seen in Figure 5, the beam stiffener 43 has a distal end 44 of the inclined load-bearing wall 5 which has a T-shaped cross-section. The beam stiffener 43 has a width in the first direction D1 of between 300 and 600 mm, and for example 400 mm. The beam stiffener 43 has a thickness of between 10 and 20 mm.

[0085] With reference to the, a cutaway view of a methane tanker 70 shows a sealed and thermally insulating tank 71 of generally prismatic shape mounted in the double hull 72 of the ship 70. The wall of the tank 71 comprises a primary sealed membrane intended to be in contact with the LNG contained in the tank, a secondary sealed membrane arranged between the primary sealed membrane and the double hull 72 of the ship 70, and two thermally insulating barriers arranged respectively between the primary sealed membrane and the secondary sealed membrane and between the secondary sealed membrane and the double hull 72.

[0086] As is known per se, loading / unloading pipelines 73 arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a marine or port terminal to transfer a cargo of LNG to or from the tank 71.

[0087] Figure 75 represents an example of a marine terminal comprising a loading and unloading berth 75, a subsea pipeline 76, and an onshore facility 77. The loading and unloading berth 75 is a fixed offshore facility comprising a movable arm 74 and a tower 78 that supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 that can be connected to the loading / unloading pipelines 73. The steerable movable arm 74 accommodates all LNG carrier sizes. An unshown connecting pipeline extends inside tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore facility 77. This facility includes liquefied gas storage tanks 80 and connecting pipelines 81 linked by the subsea pipeline 76 to the loading or unloading station 75.The subsea pipeline 76 allows the transfer of liquefied gas between the loading or unloading station 75 and the onshore facility 77 over a long distance, for example 5 km, which allows the LNG carrier 70 to be kept a long distance from the coast during loading and unloading operations.

[0088] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the land installation 77 and / or pumps equipping the loading and unloading station 75 are used.

[0089] Although the invention has been described in connection with several particular embodiments, it is clearly evident that it is by no means limited to them and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0090] The use of the verb "comporter", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

[0091] In claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

A liquefied gas storage installation comprising a supporting structure and a sealed, thermally insulated tank (71) supported by the supporting structure, the tank (71) having a first horizontal tank wall (1) fixed to a first horizontal supporting wall (4) and a second inclined tank wall (2) fixed to a second inclined supporting wall (5) joining the first horizontal supporting wall (4) at an edge (3) of the supporting structure, the edge (3) extending along an edge direction (A), each of the first and second supporting walls having an internal surface and an external surface, the first supporting wall (4) extending in a plane formed by the edge direction (A) and a first direction (D1), the second supporting wall (5) extending in a plane formed by the edge direction (A) and a second direction (D2), the first direction (D1) and the second direction (D2) being perpendicular to the direction edge (A),the first direction (D1) and the second direction (D2) being inclined at a tank angle, wherein each of the first and second tank walls comprises at least one watertight membrane (7) and a thermally insulating barrier (6) arranged between the watertight membrane (7) and the load-bearing wall, wherein the watertight membrane (7) comprises a plurality of strakes (11) each comprising at least one flat portion resting on an upper surface of the insulating barrier and at least one projecting portion protruding into the interior of the tank relative to the flat portion, the strakes (11) being juxtaposed and welded together watertight at the edges, the strakes (11) of the first tank wall (1) extending in the first direction (D1), wherein the tank wall comprises a metal connecting beam (13) arranged parallel to the edge direction (A) and anchored to the internal surface of the first and second load-bearing walls,the connecting beam (13) comprising: - a central core (17), - a first connecting flange (28) projecting from the central core (17) and being fixed to the watertight membrane (7) of the first tank wall (1), - a second connecting flange (29) projecting from the central core (17) and being fixed to the watertight membrane (7) of the second tank wall (2), - a first anchoring flange (33) projecting from the central core (17) and being aligned with the first connecting flange (28) in the first direction (D1), the first anchoring flange (33) being fixed to the second load-bearing wall (5) by means of a first connecting strip (45), the first anchoring flange (33) and the first connecting flange (28) being located on either side of the central core (17),and- a second anchoring wing (32) projecting from the central core (17) and aligned with the second connecting wing (29) and fixed to the first load-bearing wall (4) by means of a second connecting strip (45), the second anchoring wing (32) and the second connecting wing (29) being situated on either side of the central core (17), wherein the load-bearing structure comprises a plurality of stiffeners projecting perpendicularly from the external surface of the second load-bearing wall (5), the plurality of stiffeners comprising at least one beam stiffener (43) extending parallel to the edge direction (A), the beam stiffener (43) being substantially aligned in the first direction (D1) with the first anchoring wing (33) and the first connecting wing (28). Storage installation (1) according to claim 1, wherein a distance in the second direction (D2) between the beam stiffener (43) and the first anchor wing (33) is less than 50 mm, preferably less than 40 mm. Storage installation (1) according to claim 1 or claim 2, wherein the beam stiffener (43) has a width in the first direction (D1) between 300 and 600 mm, for example 400 mm. Storage installation (1) according to any one of claims 1 to 3, wherein the beam stiffener (43) has a distal end (44) of the second load-bearing wall (5), the distal end (44) having a T- or L-shaped section. Storage installation (1) according to any one of claims 1 to 4, wherein the first and second connecting strips (45) have a thickness greater than a thickness of the first and second anchor wings (32, 33) and / or greater than a thickness of the first and second connecting wings (28, 29). Storage installation (1) according to any one of claims 1 to 5, wherein the strakes (11) are made of an alloy having a coefficient of thermal expansion less than 10.10 -6 K -1 . Storage installation (1) according to any one of claims 1 to 6, wherein the strakes (11) are made either of a high manganese iron alloy having a coefficient of thermal expansion between 6 and 10.10 - 6 K -1 , for example, in the order of 7.10 -6 K -1, or in an iron and nickel alloy with a coefficient of expansion between 0.5 x 10 -6 and 2.10 -6 K -1 . Storage installation (1) according to any one of claims 1 to 7, wherein at least one flat portion is a central flat portion resting on an upper surface of the thermally insulating barrier and the strakes (11) comprise two projecting portions made in the form of two raised edges projecting into the interior of the tank relative to the central flat portion. Storage installation (1) according to any one of claims 1 to 8, wherein the connecting beam (13) is made of an iron and nickel alloy having a coefficient of expansion between 0.5.10 -6 and 2.10 -6 K -1 . Storage installation (1) according to any one of claims 1 to 9, wherein the load-bearing structure comprises anchor plates (19) extending in the edge direction (A) and projecting from the inner surface of the first and second load-bearing walls (4, 5), the first connecting strip (45) being fixed to one of the anchor plates (19) of the second load-bearing wall (5), and the second connecting strip (45) being fixed to one of the anchor plates (19) of the first load-bearing wall (4). Storage installation (1) according to any one of claims 1 to 10, in which the tank comprises two sealed membranes and two thermally insulating barriers, the two sealed membranes being fixed to the connecting beam (13) whose central core (17) is hollow. Storage installation (1) according to any one of claims 1 to 11, wherein the beam stiffener (43) has a thickness of between 10 and 20 mm. Storage installation (1) according to any one of claims 1 to 12, wherein the plurality of stiffeners comprises a network of primary stiffeners (39) and a network of secondary stiffeners (40), the primary stiffeners (39) having a dimension in the first direction (D1) greater than the secondary stiffeners (40), the network of secondary stiffeners (40) comprising the beam stiffener (43). Storage installation (1) according to claim 13, wherein the primary stiffener network (39) comprises second primary stiffeners parallel to the second direction (D2) and primary edge stiffeners parallel to the edge direction (A), and the secondary stiffener network (40) comprises second secondary stiffeners (41) parallel to the second direction (D2) and secondary edge stiffeners (42) parallel to the edge direction (A), the secondary edge stiffeners (42) including the beam stiffener (43). Vessel (70) for the transport of a cold liquid product, the vessel comprising a double hull (72) and a storage facility according to any one of claims 1 to 14, the double hull comprising the load-bearing structure of the storage facility. Transfer system for a cold liquid product, the system comprising a vessel (70) according to claim 15, insulated pipes (73, 79, 76, 81) arranged to connect the vessel's tank (71) to a floating or land-based storage facility (77) and a pump to drive a flow of cold liquid product through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank. Method of loading or unloading a ship (70), in which a cold liquid product 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 15.

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