FR3111411A1 - Liquid dome of a storage tank for liquefied gas - Google Patents

Abstract

Liquid dome of a storage tank for liquefied gas. The invention relates to a storage installation (1) for liquefied gas and a leaktight and thermally insulating tank (71) comprising a loading/unloading opening (10) comprising a lower lid (23) having lateral closing strips (60, 61) disposed adjacent structural insulation (40) and said side closure strips (60, 61) are mechanically attached to adjacent structural insulation (40). Figure for abstract: Fig. 1

Description

Liquid dome of a storage tank for liquefied gas

The invention relates to the field of storage facilities for liquefied gas comprising a sealed and thermally insulating tank, with membranes. 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 also 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.

The document FR2991430 describes a storage facility for liquefied gas comprising a sealed and thermally insulating tank integrated into a supporting structure consisting of the double hull of a ship. Each wall of the tank comprises a secondary thermally insulating barrier, a secondary sealing membrane, a primary thermally insulating barrier and a primary sealing membrane, these various elements constituting the main structure of the liquefied gas storage tank.

In an area located at the top of the tank, the tank has an opening portion called the liquid dome. In this zone, the support structure is locally interrupted so as to delimit a loading/unloading opening intended to be traversed by fluid loading/unloading pipes. This loading/unloading opening, called Liquid Dome, comprises, like the main structure of the tank, an insulation or thermally insulating barrier as well as an element forming a primary sealing membrane.

The liquid dome is conventionally assembled independently of the tank which comprises the tank itself, of polyhedral shape, as well as the opening intended to receive the liquid dome, generally located at the rear end of the tank. This opening has a square or rectangular section. The polyhedral tank up to the opening intended to receive the liquid dome forms the main structure and is calpinated with at least one metal sealing membrane and a thermal insulation barrier, as presented previously. The main structure is made as a storage facility for liquefied gas of a structure, typically a ship, then the liquid dome is arranged to close the opening of the tank, while allowing in particular the passage of loading tubes/ unloading of liquefied gas and other access for operators (designated “Man Hole”) or material (designated “Material Hole”).

As the liquid dome is assembled as a block intrinsically having its sealing membrane and its thermal insulation barrier, it is necessary to make a tight connection of the sealing membrane of the liquid dome to that of the main structure. This connection operation is made possible thanks to the use of four lateral closure strips which are welded in a sealed manner between the main structure and the sealing membrane of the liquid dome. A sequence for mounting/assembling a liquid dome in or on the main structure of a liquefied gas tank is illustrated in figures 2 to 4.

Nevertheless, after multiple tests and experiments, the applicant has discovered that, as soon as the liquid dome is mounted on the main structure of the storage facility, when the ship is subjected to very high mechanical stresses, due in particular to ballasting conditions of the ship, and/or critical environmental conditions, typically significant longitudinal bending phenomena in the center line of the ship, there may appear a risk of buckling of these lateral closure strips causing cracks at the level of their welds and therefore an at least partial loss of sealing.

Based on this analysis, the applicant intends to remedy any weakness that may appear in this area by simply and effectively improving the mechanical strength of these side closure strips ensuring the tight connection between the liquid dome and the main structure.

Thus, the present invention relates to a storage facility for liquefied gas comprising a supporting structure and a sealed and thermally insulating tank arranged in the supporting structure,
the sealed and thermally insulating tank comprising a main structure formed by a plurality of tank walls connected to each other and fixed to the support structure, the main structure defining an internal storage space, the main structure comprising at least one membrane of sealing 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 a substantially planar upper load-bearing wall; the sealing membrane, the thermally insulating barrier of the main structure and the upper load-bearing wall being interrupted locally so as to delimit a loading/unloading opening intended to be traversed by fluid loading/unloading pipes; wherein the tank has a lid disposed in the loading / unloading opening;
wherein the lid includes a lid top wall, a lid bottom wall, and a thermal insulation structure located between the lid bottom wall and the lid top wall;
in which the lower lid wall comprises a plurality of flat metal plates assembled to each other in a leaktight manner, including at least one main partition and two lateral closing strips each intended to close, in a leaktight manner, and connect the said lower lid wall to the main structure.

The invention is characterized in that at least one of the closing side strips is adjacent to a structural insulation and in that said closing side strip is mechanically fixed to the adjacent structural insulation.

Thus, the applicant has found, after multiple tests and analyses, that these lateral closing strips could, due to the structure or operation of the ship and in particular in particularly harsh environmental circumstances, in particular due to the cold outside, the conditions sea and/or weather, undergo mechanical stresses such that the tightness of their fixing welds was likely to fail.

Based on these analyses, the applicant proposes a simple, effective and inexpensive system for securing and totally sealing these particular areas. First these adjacent side strips are placed adjacent to structural insulation and then the strips are mechanically attached, at a plurality of points, to this structural insulation.

The applicant was able to verify, after several tests, that such an arrangement made it possible to maintain the tightness of the storage installation for liquefied gas at the level of these lateral closing strips which are certainly one of the most critical locations, in terms of mechanical stresses, for a structure such as a ship.

The expression "mechanical fixing" means the fact that the fixing between the two elements considered is made possible by an element forming a physical connection, without any recourse to electrical, magnetic, electromagnetic or even chemical energy (bonding or the like). .

In the context of the present invention, a thermal insulation is said to be "structural" when the latter has properties of strength and/or mechanical resistance, while a thermal insulation is said to be "non-structural" when the latter does not have such properties. mechanical properties.

Thus, in the context of the present invention, structural thermal insulation may consist of a plywood box or a polymer foam having a density at least equal to ninety (90) kilos per cubic meter (kg.m ^{- 3} ), called "high density polymer foam", preferably a polyurethane foam. One of these two structural thermal insulations is able to receive a mechanical means of fixing - in this case plywood - while the other - in this case high density polymer foam - does not have this capacity, or not optimally or preferred. By convention, structural thermal insulation capable of receiving or accommodating mechanical fixing is defined by the expression “mechanical structural (thermal) insulation”.

This is why, according to a particularly advantageous aspect of the invention, the side closure strip is mechanically fixed to one or to the adjacent mechanical structural insulation.

In the context of the present invention, a non-structural thermal insulation can consist of glass wool or a polymer foam having a density of less than 90 kg.m ^-3 , called low density polymer foam, preferably still polyurethane foam. .

By convention, the terms "external" and "internal" are used to define the relative position of one element in relation to another, with reference to the inside and outside of the tank.

Other advantageous features of the invention are briefly presented below:

According to a possibility offered by the invention, the thermal insulation structure of the lid consists of structural insulations and non-structural insulations.

Thus, it is understood in particular that a thermal insulation box is composed of a structural portion, namely plywood, and a non-structural portion, namely glass wool or a low-density polymer foam housed in the structural portion.

According to a variant embodiment of the invention, the thermal insulation structure of the lid consists solely of structural thermal insulation. In this variant, the thermal insulation structure of the lid can participate in or help to maintain the tightness of the storage installation for liquefied gas at the level of the lateral closure band(s) according to the present invention.

Advantageously, the mechanical fastening consists of a plurality of screwing, riveting or nailing, preferably of a plurality of screwing.

Preferably, the lower cover wall, including the main partition and the side closing strips, is made of iron and nickel alloy having a coefficient of thermal expansion of between 0.5×10 ^-6 and 2×10 ^-6 K ^-1 , of preferably the lower cover wall is made of Invar ^® .

Preferably, the flat metal plates of the lower wall of the cover, of which at least the main partition and the lateral closing strips are fixed together by welding.

Preferably, the lateral closure strips have a length of between 400 and 550 centimeters, preferably between 440 and 510 centimeters, a width of between 20 and 40 centimeters, preferably between 25 and 30 centimeters, and a thickness of between 1. 2 and 1.8 millimeters.

As can be seen in particular in FIG. 4, it is important to note that there are four lateral closing strips intended to close and to connect, in a sealed manner, the lower wall of the cover to the main structure, nevertheless the present invention is intended to apply in particular to the lateral closure strips extending along an x'x axis perpendicular to the longitudinal axis of the ship because, in accordance with the applicant's analyses, it is these strips which are subjected to the most severe mechanical stresses , in particular buckling due to compression on the ends of the strips by ship beam elongation. In its broadest definition, the invention is to be applied to at least one of its two lateral closure strips, very advantageously on the two closure strips, extending along the axis x'x but in the following , the invention is illustrated by considering that it is applied to the two lateral closure strips extending along the x'x axis.

Of course, it is also possible to envisage applying the present invention to the four lateral closure bands, i.e. the other two bands extending along the longitudinal axis of the ship.

According to a first preferred embodiment, the side closure strip consists of three strips, one central and two end, only the central strip being mechanically fixed to the adjacent structural insulation.

Advantageously, in this first embodiment, the end strips cover the mechanical fastening in a sealed manner.

In the context of this first embodiment, the end strips are preferably welded in a sealed manner to the central strip.

Still within this framework, advantageously, the central strip having a width of between 10 and 20 centimeters and the end strips having a width of between 8 and 15 centimeters.

According to a second preferred embodiment, the side closure strip comprises a plurality of holes for the mechanical connection by screwing with the adjacent structural insulation.

In the context of this second embodiment, each orifice is preferably arranged so as to have a space between them of between 10 and 30 centimeters, preferably between 15 and 25 centimeters.

Still within this framework, each orifice is advantageously covered with a metal part, preferably of circular shape and made of a material identical to that of the side closure strip, fixed in a sealed manner, preferably by welding, to the side strip closing.

According to an advantageous embodiment, the structural insulation of the thermal insulation structure of the lid consists of a plurality of boxes, preferably made of plywood, juxtaposed to each other and filled with an insulating filling.

According to an advantageous embodiment, the non-structural insulation of the thermal insulation structure of the lid consists of at least one block of polymer foam, such as for example low-density polyurethane foam (less than or equal to 90 kg.m ^-3 ).

Advantageously, the sealing membrane is a primary sealing membrane, the thermally insulating barrier is a primary thermally insulating barrier and in which the main structure of the vessel comprises, in a direction of thickness from the outside towards the inside of the tank, a secondary thermally insulating barrier fixed to the load-bearing structure, a secondary sealing membrane carried by the secondary thermally insulating barrier, the primary thermally insulating barrier carried by the secondary sealing membrane, and the primary sealing membrane carried by the primary thermally insulating barrier intended to be in contact with the liquefied gas.

The invention relates more particularly to a ship for transporting a cold liquid product, the ship comprising a double hull and a storage installation as described above arranged in the double hull.

Advantageously, the vessel comprises an internal deck and an external deck, the internal upper load-bearing wall of the load-bearing structure being formed by the internal deck and the external upper load-bearing wall being formed by the external deck.

The invention also relates to a transfer system for a cold liquid product, the system comprising a ship as described above, insulated pipes arranged so as to connect the tank installed in the hull of the ship to an external floating storage installation or land and a pump to drive a flow of cold liquid product through the insulated pipes from or to the external floating or land storage installation to or from the tank of the ship.

Finally, the present invention relates to a method for loading or unloading a ship as described above, in which a cold liquid product is conveyed through insulated pipes from or to an external floating or terrestrial storage installation towards or from the vessel's tank.

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.

Figure 1 is a schematic sectional view of a liquid dome according to the first or the second embodiment of the invention.

FIG. 2 schematically illustrates a first step of assembling a liquid dome in which the cover of the liquid dome and the part of the main structure in which the liquid dome cover will be inserted and then connected are visible.

Figure 3 schematically illustrates a second step of assembling the liquid dome, following the sequence illustrated in Figure 2, in which the cover of the liquid dome is inserted into the main structure.

Figure 4 schematically illustrates a third step of assembling the liquid dome, following the sequences illustrated in Figures 2 and 3, in which the four lateral closing strips are placed opposite the cover and ready to be connected in such a way seals the latter with the main structure.

Figure 5 is a sectional view at the level of a side closure strip, according to a first embodiment of the invention.

Figure 6 is a schematic sectional view of a side closure strip according to the first embodiment of the invention.

Figure 7 is another sectional view at the level of a side closure strip, still according to the first embodiment of the invention.

Figure 8 is a schematic sectional view of a side closure strip according to a second embodiment of the invention.

FIG. 9 is a top view making it possible to visualize in particular the metal parts covering, in a sealed manner, the orifices serving to mechanically fix the lateral closing strips, according to the second embodiment of the invention.

FIG. 10 is a cutaway schematic representation of an LNG tanker storage facility and a loading/unloading terminal for this tank.

The term "vertical" here means extending in the direction of the earth's gravity field. The term "horizontal" here means extending in a direction perpendicular to the vertical direction.

In the following, the present invention is illustrated with a ship. Indeed, it is on this type of structure housing a storage installation according to the state of the art that the applicant was able to update potential malfunctions and thus resolve them thanks to the present invention. Nevertheless, it is possible to envisage applying the characteristics of the present invention to a structure of a different nature, such as for example a structure of the terrestrial or maritime tank type (known as “GBS” meaning “Global Base Storage”).

In Figure 1, there is shown schematically a portion of a storage facility 1, at the level of the liquid dome, comprising a support structure 2. Inside the support structure 2, the storage facility 1 comprises a sealed and thermally insulating tank 71 which will be described later.

The load-bearing structure 2 comprises a plurality of walls connected to each other and in particular an upper load-bearing wall 3 which is located, as can be seen in figure 1, at the top of the storage installation 1.

When the storage facility 1 is positioned on a ship such as an LNG carrier, the load-bearing structure 2 is formed by the double hull of the ship. The upper load-bearing wall 3 is thus called the internal deck 3 of the ship while there is also an external deck, not visible in figure 1.

The tank 71 comprises a main structure formed of a bottom wall (not shown), a ceiling wall 3 (upper wall or even internal bridge), two cofferdam walls 4 connecting the bottom wall to the ceiling wall 3 and located at the front and at the rear when the storage installation 1, two side walls (not shown) and optionally two to four bevel walls (not shown) connecting the side walls to the bottom wall or to the wall ceiling 3. The walls of the tank 71 are thus connected to each other so as to form a polyhedral structure and to delimit an internal storage space.

In order to load and unload the tank 71 with liquefied gas, the storage installation 1 comprises a loading/unloading opening 10 locally interrupting the ceiling wall 3 of the tank 71 so as to allow in particular loading/unloading pipes, not shown in the appended figures, to reach the bottom of the tank 71 by crossing this opening 10. The orifices necessary for these ducts in the liquid dome are particularly visible in the appended figure 2.

The storage facility 1 also comprises a loading/unloading tower, not shown in the appended figures, located to the right of the opening 10 and forming a support structure for the loading/unloading pipes, not visible in the appended figures. , over the entire height of the tank 71 as well as for the pumps, not shown in the appended figures. It is important to note that this loading/unloading tower is assembled with the cover 12 of the liquid dome, once the layout of the tank 71 has been completed.

Thus, the storage installation 1 comprises a cover 12 arranged in the loading/unloading opening 10 in order to close off the internal storage space at the level of said opening 10. The cover 12 comprises accesses allowing the loading/unloading pipes unloading to cross the cover 12 as well as two crossing accesses of larger diameter, one called the man access (or "Man Hole") and the other called the material access (or "Material Hole"), also visible in figures 2 to 4.

In the context of the present invention, this lid 12 also designates the “liquid dome”. The loading/unloading opening 10 has a rectangular or square outline.

Tank 71 is a membrane tank for storing liquefied gas. The main structure 6 of the tank 71 comprises a multilayer structure comprising, from the outside inwards, a secondary thermally insulating barrier 16 comprising insulating elements, resting against the supporting structure 2, 3 or 4 in the appended figures, a secondary sealing membrane 17 resting against the secondary thermally insulating barrier 16, a primary thermally insulating barrier 18 comprising insulating elements, resting against the secondary sealing membrane 17 and a primary sealing membrane 19 intended to be in contact with the liquefied gas, in liquid or gaseous form, contained in tank 71.

According to one embodiment, the main structure of the tank 71 is made using technology NO 96 ^® which is described in particular in the document FR-A-2867831. This document is incorporated here by reference to describe the arrangements of the main structure 6, in particular at the level of the elements 16, 17, 18 and 19.

The lid 12 has a multilayer structure comprising an upper lid wall 22, a lower lid wall 23 and a thermal insulation structure 24 disposed between these walls 22, 23. The lower lid wall 23 comprises a plurality of plates flat metal assembled to each other in a sealed manner including at least one main partition and two pairs of side closure strips 60, 61 described in more detail below. Thus, the lower cover wall 23 forms the primary sealing membrane of the cover 12, which is why it must be connected to the primary membrane 19 of the main structure 6. As we will see in more detail later, this connection is ensured by the lateral closing strips 60, 61. The upper cover wall 22 is fixed in a sealed manner to the internal bridge 3 all around the opening 10 so that it is the upper cover wall 22 which plays the role of secondary sealing membrane 17. The upper cover wall 22 is made using a metallic material, for example stainless steel.

The thermal insulation structure 24 comprises a plurality of thermal insulation elements juxtaposed to each other which may be of similar or different constitution. They may be so-called “structural” insulating elements 40 essentially having properties or mechanical strength characteristics that are superior, or even much superior, to the so-called “non-structural” insulating elements 41. The structural insulating elements 40 can be blocks of foam optionally fiber-reinforced high-density polymer or plywood or composite wood boxes filled with insulating packing (this being inherently non-structural thermal insulation) such as glass wool, polymer foam or perlite. The non-structural insulating elements 41 can be blocks of low-density polymer foam or even glass wool. The expressions "structural insulating element" and "non-structural insulating element" refer to the fact that these elements have the mechanical properties set out above, in addition to their existing thermal insulation properties for these two types of elements 40, 41.

Figures 2 to 4 illustrate a sequence of assembly and assembly of the cover 12 in the opening 10. As can be seen in Figures 2 and 3, the dimensions of the cover 12 are substantially the same as those of the opening 10. Once the cover 12 is in place in the opening 10, four side closing strips 60, 61 are positioned to ensure the sealed connection between the cover 12, more precisely the lower wall of the cover 23.

The lower cover wall 23, the side closing strips 60, 61 and the primary sealing membrane 19 of the main structure 6 are advantageously all made of the same material, having a very low coefficient of thermal expansion such as Invar. ^® . The nature of identical metal alloy of these three elements 23, 19 and 60, 61 makes it possible to facilitate their sealed connection by welding. In the appended figures, the welds between different elements are illustrated schematically in the appended figures 6 and 8 by black triangles 20.

Two of the four lateral closure strips, ie the strips 61, extend along the longitudinal axis of the vessel while the other two lateral closure strips 60 extend along an axis x'x perpendicular to the longitudinal axis of the vessel . As explained above, the applicant has discovered that the strips 60 are likely to undergo much more severe buckling than the strips 61, which is why the present invention is above all intended to be implemented for at least one of these strips 60 , ideally the two strips 60. In the following, the invention is illustrated with a single strip 60 but again, it is advantageous and even desirable that the invention apply to the two strips 60, or even also to the other two strips 61 without the application of the present invention thereto being required.

In the context of this invention, it is crucial to dispose adjacent to the side closing strip 60 adjacent to a structural thermal insulation 40, over the entire length where the mechanical fastening between the latter 40 and the strip 60 is going to be carried out. This aspect of the arrangement of the structural thermal insulation 40 in contact with the lateral closure strip 60 essentially appeared to the applicant on the one hand for the aforementioned fixing but also to ensure the support of the strip 60 and the absorption by the structural insulation 40 from the mechanical forces, mainly liable to a buckling phenomenon, undergone by the strip 60.

Figures 5 to 7 show a first embodiment of the invention in which the lateral closure strip 60 consists of, or formed from, three strips: a central strip 65 and two end strips 66. In this mode embodiment, only the central strip 65 is mechanically fixed to the adjacent structural thermal insulation 40, the two end strips 66 being fixed in a sealed manner, by welding, to this central strip 65. Advantageously, the dimensions – width, length , thickness - of the two end strips 66 are not strictly identical because of the arrangements of the thermal insulation structure 24 for one - that fixed to the lower wall of the cover 23 - and of the arrangements of the main structure 6 for the other – either that fixed to the primary sealing membrane 19. The central strip 65 advantageously has a length identical to that of the end strips 66 but a width and a thickness which may differ depending on the length of the strip. management, of the order of a few millimeters for the width and one or two millimeters for the thickness.

As can be seen in particular in Figures 5 and 7, the adjacent structural thermal insulation 40 advantageously has a recess 67 for each screw 68 or the like intended to mechanically attach the side closure strip 60 to the structural insulation 40. Thus , the head of the mechanical means 68, in this case the screw, does not come into contact with the end strips 66.

Figures 8 and 9 illustrate a second embodiment of the invention. Here, the side closure strip 60 consists of a single strip pierced with a plurality of orifices 69 advantageously spaced apart from each other by the same length/distance. Each of these holes 69 is intended to receive a screw 68 or the like, that is to say a mechanical means of fixing 68 of the strip 60 to the structural insulation 40 adjacent.

Once the mechanical means 68 has been put in place and arranged in function in each of the orifices 69, the orifice 69 is covered with a mechanical part 90 fixed in a sealed manner to the lateral closure strip 60. Like the first mode embodiment of the invention, at the level of each orifice 69, the lateral closure strip 60 forms a recess 67 allowing the screw head 68 or the like not to come into contact with the mechanical part 90, once the latter 68 installation and function in its dedicated hole 69. It is also possible, as an alternative or in addition to this recess 67, for the adjacent structural insulation 40 to include the same recess having the same function vis-à-vis the mechanical fastening means.

FIG. 10 represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipeline 76 and an onshore installation 77. The loading and unloading station 75 is a fixed off-shore installation comprising an 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 shore installation 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 (18)

Storage installation (1) for liquefied gas comprising a support structure (2) and a sealed and thermally insulating tank (71) arranged in the support structure (2),
the sealed and thermally insulating tank (71) comprising a main structure (6) formed by a plurality of tank walls connected to each other and fixed to the supporting structure (2), the main structure (6) defining an internal space of storage, the main structure (6) comprising at least one sealing membrane (17, 19) and at least one thermally insulating barrier (16, 18), the thermally insulating barrier (16, 18) being placed between the sealing (17, 19) and the supporting structure (2);
the load-bearing structure (2) comprising an upper load-bearing wall (3) which is substantially planar;
the sealing membrane (17, 19), the thermally insulating barrier (16, 18) of the main structure (6) and the upper load-bearing wall (3) being interrupted locally so as to delimit a loading/unloading opening (10 ) intended to be crossed by fluid loading/unloading lines;
wherein the tank (71) has a cover (12) disposed in the loading/unloading opening (10);
wherein the cover (12) comprises a cover top wall (22), a cover bottom wall (23) and a thermal insulation structure (24), located between the cover bottom wall (23) and the top wall cover (22);
in which the lower lid wall (23) comprises a plurality of flat metal plates assembled together in a sealed manner, including at least one main partition and two lateral closing strips (60, 61) each intended to close, in a sealed manner , and connecting said lower cover wall (23) to the main structure (6);
characterized in that at least one of the side closure strips (60) is adjacent structural insulation (40) and said side closure strip (60) is mechanically attached to the adjacent structural insulation (40). Storage installation (1) according to claim 1, in which the mechanical fastening (68) consists of a plurality of screwing, riveting or nailing, preferably of a plurality of screwing. Storage installation (1) according to Claim 1, in which the lower cover wall (23), the main partition of which and the lateral closure strips (60, 61), is 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 , preferably the lower cover wall (23) is made of ^Invar® . Storage installation (1) according to one of Claims 1 to 3, in which the flat metal plates of the lower cover wall (23) of which at least the main partition and the lateral closing strips (60, 61) are fixed together by soldering. Storage installation (1) according to one of Claims 1 to 4, in which the lateral closure strips (60, 61) have a length of between 400 and 550 centimeters, preferably between 440 and 510 centimeters, a width of between 20 and 40 centimeters, preferably between 25 and 30 centimeters, and a thickness of between 1.2 and 1.8 millimeters. Storage installation (1) according to one of Claims 1 to 5, in which the lateral closing strip (60) consists of three strips, one central (65) and two end (66), only the central strip ( 65) being mechanically attached to the adjacent structural insulation (40). Storage installation (1) according to claim 6, in which the end bands (66) seal the mechanical fixing. Storage installation (1) according to Claim 6 or 7, in which the end strips (66) are sealed to the central strip (65). Storage installation (1) according to one of Claims 6 to 8, in which the central strip (65) having a width of between 10 and 20 centimeters and the end strips (66) having a width of between 8 and 15 centimeters. Storage installation (1) according to one of Claims 1 to 5, in which the lateral closing strip (60) comprises a plurality of orifices (69) for the mechanical connection by screwing with the structural insulation (40) adjacent . Storage installation (1) according to Claim 10, in which each orifice (69) is arranged so as to have a space between them of between 10 and 30 centimeters, preferably between 15 and 25 centimeters. Storage installation (1) according to one of Claims 10 or 11, in which each orifice (69) is covered with a metal part (90), preferably of circular shape and made of a material identical to that of the lateral band closure (60), fixed in a sealed manner, preferably by welding, to the side closure strip (60). Storage facility (1) according to any one of the preceding claims, in which the structural insulation (40) of the thermal insulation structure (24) of the cover (12) consists of a plurality of boxes, preferably of wood plywood, juxtaposed to each other and filled with an insulating filling. Storage facility (1) according to any one of the preceding claims, in which the sealing membrane is a primary sealing membrane (19), the thermally insulating barrier is a primary thermally insulating barrier (18) and in which the main structure (6) of the tank (71) comprises, in a direction of thickness from the outside towards the inside of the tank (71), a secondary thermally insulating barrier (16) fixed to the load-bearing structure, a membrane secondary sealing layer (17) carried by the secondary thermally insulating barrier (16), the primary thermally insulating barrier (18) carried by the secondary sealing membrane (17), and the primary sealing membrane (19) carried by the primary thermally insulating barrier (18) being intended to be in contact with the liquefied gas. Vessel (70) for transporting a cold liquid product, the vessel comprising a double hull (72) and a storage installation (1) according to one of Claims 1 to 14 arranged in the double hull. Vessel (70) according to Claim 15, in which the vessel (70) comprises an internal deck (4) and an external deck (5), the internal upper load-bearing wall (4) of the load-bearing structure being formed by the internal deck ( 4) and the outer upper load-bearing wall (5) being formed by the outer bridge (5). Transfer system for a cold liquid product, the system comprising a vessel (70) according to claim 15 or claim 16, insulated pipes (73, 79, 76, 81) arranged to connect the tank (71) installed in the ship's hull to an external floating or onshore 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 onshore storage facility to or from the tank of the ship. A method of loading or unloading a ship (70) according to claim 15 or claim 16, in which a cold liquid product is conveyed through insulated pipes (73, 79, 76, 81) from or to an external installation of floating or land storage (77) to or from the ship's tank (71).