WO2021254999A1

WO2021254999A1 - Liquid dome of a storage tank for liquefied gas

Info

Publication number: WO2021254999A1
Application number: PCT/EP2021/066050
Authority: WO
Inventors: Guillaume LE ROUX; Paul Baron; Sébastien DELANOE
Original assignee: Gaztransport Et Technigaz
Priority date: 2020-06-15
Filing date: 2021-06-15
Publication date: 2021-12-23
Also published as: CN115667784A; FR3111411A1; FR3111411B1; KR20230011995A

Abstract

The invention relates to a storage facility (1) for liquefied gas and a leak-tight and thermally-insulated tank (71) having a loading/unloading opening (10) comprising a lower lid (23) having lateral closing strips (60, 61) adjacent to a structural insulation (40), wherein said lateral closing strips (60, 61) are mechanically fixed to the adjacent structural insulation (40).

Description

Title of the invention: 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) exhibiting by example a temperature between -50 ° C and 0 ° C, or for the transport of Liquefied Natural Gas (LNG) at approximately -162 ° C at atmospheric pressure. These tanks can 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 serving as fuel for the propulsion of the floating structure.

[0002] Document FR2991430 describes a storage installation for liquefied gas comprising a sealed and thermally insulating tank integrated into a supporting structure formed by the double hull of a ship. Each wall of the vessel includes a secondary thermally insulating barrier, a secondary waterproofing membrane, a primary thermally insulating barrier and a primary waterproofing membrane, these various elements constituting the main structure of the liquefied gas storage vessel.

[0003] In an area located at the top of the tank, the tank has an opening portion called the liquid dome. In this zone, the supporting structure is interrupted locally so as to delimit a loading / unloading opening intended to be crossed by fluid loading / unloading pipes. This loading / unloading opening, called the Liquid Dome, has, like the main structure of the tank, an insulation or thermally insulating barrier as well as an element forming a primary waterproofing membrane.

[0004] 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 accommodate the liquid dome, generally located at the rear end of tank. This opening has a section of square or rectangular shape. The polyhedral tank up to the opening intended to receive the liquid dome forms the main structure and is calpified with at least one metallic waterproofing membrane and a thermal insulation barrier, as presented above. The main structure is produced as a storage installation for the liquefied gas of a structure, typically a ship, then the liquid dome is arranged to close the opening of the tank, while in particular allowing the passage of loading tubes / liquefied gas unloading and other accesses for operators (designated "Man Hole") or equipment (designated "Material Hole").

The liquid dome being assembled as a block intrinsically having its waterproofing membrane and its thermal insulation barrier, it is necessary to make a tight connection of the waterproofing membrane of the liquid dome to that of the main structure. This connection operation is made possible by the use of four side closure strips which are sealed between the main structure and the waterproofing membrane of the liquid dome. A sequence of mounting / assembling a liquid dome in or on the main structure of a liquefied gas tank is shown in Figures 2 to 4.

[0006] 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 installation, when the ship is subjected to very strong mechanical stresses, the particularly due to ballasting conditions of the ship, and / or critical environmental conditions, typically the significant phenomena of longitudinal bending in the axis of the ship, we can see a risk of buckling of these lateral closing bands resulting in cracks at their welds and therefore at least partial loss of sealing.

On the basis of this analysis, the Applicant intends to remedy a possible weakness likely to appear in this zone by simply and effectively improving the mechanical strength of these lateral closure bands ensuring the tight connection between the liquid dome and the main structure. [0008] Thus, the present invention relates to a storage installation 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 walls of tank connected to each other and fixed to the supporting structure, the main structure defining an internal storage space, the main structure comprising at least one waterproofing membrane and at least one thermally insulating barrier, the thermally insulating barrier being placed between the waterproofing membrane and supporting structure; the supporting structure comprising a substantially planar upper supporting wall; the waterproofing membrane, the thermally insulating barrier of the main structure and the upper bearing wall being interrupted locally so as to delimit a loading / unloading opening intended to be crossed by fluid loading / unloading conduits; wherein the vessel has a cover disposed in the loading / unloading opening; wherein the cover comprises a cover top wall, a cover bottom wall, and a heat insulating structure located between the cover bottom wall and the cover top wall; in which the lower cover wall comprises a plurality of flat metal plates assembled together in a sealed manner, including at least one main partition and two lateral closure strips each intended to close, in a sealed manner, and to connect said lower cover wall to the main structure.

[0009] The invention is characterized in that at least one of the side closure strips is adjacent to a structural insulation and in that said side closure strip is mechanically attached to the adjacent structural insulation.

[0010] Thus, the Applicant has observed after multiple tests and analyzes that these lateral closing bands could, due to the structure or the operation of the ship as well as in particular in particularly harsh environmental circumstances, in particular due to the cold outside , sea and / or weather conditions, undergo mechanical stresses such that the tightness of their fixing welds was likely to fail. On the basis of these analyzes, the applicant proposes a simple, efficient and inexpensive system for completely securing and sealing these particular areas. First these adjacent side bands are placed adjacent to structural insulation and then the bands 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 closure bands which are certainly one of the most critical locations , in terms of mechanical stresses, for a structure such as a ship.

The expression "mechanical attachment" is understood to mean the fact that the attachment 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, thermal insulation is called "structural" when the latter has properties of resistance and / or mechanical resistance while thermal insulation is called "non-structural" when the latter does not present. no such mechanical properties.

Thus, in the context of the present invention, structural thermal insulation can consist of a box of plywood or polymeric foam having a density at least equal to ninety (90) kilograms per cubic meter (kg .nr ³ ), called “high density polymer foam”, preferably a polyurethane foam. One of these two structural thermal insulations is suitable for receiving a mechanical fixing means - in this case plywood wood - while the other - in this case high density polymer foam - does not have this capacity, or not optimally or preferred. By convention, a structural thermal insulation capable of receiving or receiving a mechanical fixing is defined by the expression “mechanical structural (thermal) insulation”. This is why, according to a particularly advantageous aspect of the invention, the lateral 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.nr ³ , called low density polymer foam, preferably always of polyurethan foam.

By convention, the terms "external" and "internal" are used to define the relative position of an element with respect to another, by reference to the interior and exterior of the vessel.

[0019] Other advantageous features of the invention are presented succinctly below:

[0020] According to one possibility offered by the invention, the thermal insulation structure of the cover consists of structural insulation and non-structural insulation.

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 polymer foam density housed in the structural portion.

[0022] According to an alternative embodiment of the invention, the thermal insulation structure of the cover consists only of structural thermal insulation. In this variant, the thermal insulation structure of the cover can participate in or help to maintain the tightness of the storage facility for liquefied gas at the level of the side closure strip (s) according to the present invention.

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

Preferably, the lower cover wall, including the main partition and the side closure strips, is made of an iron and nickel alloy having a thermal expansion coefficient of between 0.5.10 ⁶ and 2.10 ⁶ K ^-1 , preferably the lower cover wall is made of Invar ^® . Preferably, the flat metal plates of the lower cover wall of which at least the main partition and the lateral closure strips are fixed together by welding.

Preferably, the lateral closure bands 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 closure strips intended to close and to connect, in a sealed manner, the lower cover wall to the main structure, nevertheless the present invention intends to apply in particular to the lateral closure bands extending along an axis x'x perpendicular to the longitudinal axis of the ship because, in accordance with the applicant's analyzes, it is these bands which are subjected to the mechanical stresses the most severe, in particular buckling due to compression on the ends of the bands by the 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 x'x axis but in the following , the invention is illustrated by considering that it is applied to the two lateral closure bands extending along the axis x'x.

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

[0029] According to a first preferred embodiment, at least one lateral closure strip consists of three elements, a central element and two end elements, only the central element being mechanically fixed to the adjacent structural insulation.

[0030] Advantageously, in this first embodiment, the end elements sealably cover the mechanical fastening.

In the context of this first embodiment, the end elements are preferably welded in a sealed manner to the central element. Still in this context, advantageously, the central element has a width of between 10 and 20 centimeters and the end elements have a width of between 8 and 15 centimeters.

[0033] According to a second preferred embodiment, at least one lateral 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, preferably, each orifice is arranged so as to have a space between them of between 10 and 30 centimeters, preferably between 15 and 25 centimeters.

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

According to an advantageous embodiment, the thermal insulation structure of the cover and / or the structural insulation adjacent to a lateral closing strip consists of a plurality of boxes, preferably in plywood, juxtaposed to each other and filled with an insulating pad.

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

Advantageously, the waterproofing membrane is a primary waterproofing membrane, the thermally insulating barrier is a primary thermally insulating barrier and in which the main structure of the tank comprises, in a thickness direction from the outside towards inside the tank, a secondary thermally insulating barrier attached to the supporting structure, a secondary waterproofing membrane carried by the secondary thermally insulating barrier, the primary thermally insulating barrier being carried by the secondary waterproofing membrane, and the membrane primary sealing carried by the primary thermally insulating barrier being intended to be in contact with the liquefied gas. The invention relates more particularly to a ship for the transport of 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 has an internal deck and an external bridge, an internal upper load-bearing wall of the load-bearing structure being formed by the internal bridge and an external upper load-bearing wall being formed by the external bridge.

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

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 storage installation. or land to or from the vessel's tank.

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

[0044] [Fig.1] Figure 1 is a schematic sectional view of a liquid dome according to the first or the second embodiment of the invention.

[0045] [fig.2] Figure 2 schematically illustrates a first assembly step of a liquid dome in which are visible the cover of the liquid dome and the part of the main structure in which will be inserted and then connected the cover of liquid dome. [0046] [Fig.3] 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.

[0047] [Fig.4] 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 bands are placed vis-à-vis cover and ready to connect the latter in a sealed manner with the main structure.

[0048] [Fig.5] Figure 5 is a sectional view at a side closure strip, according to a first embodiment of the invention.

[0049] [Fig.6] Figure 6 is a schematic sectional view of a side closure strip according to the first embodiment of the invention.

[0050] [Fig.7] Figure 7 is another sectional view at a side closure strip, still according to the first embodiment of the invention.

[0051] [Fig.8] 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 closure strips, according to the second embodiment of invention.

[0053] [fig.10] Figure 10 is a cut-away schematic representation of an LNG vessel storage facility and a loading / unloading terminal of 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 structures housing a storage installation according to the state of the art that the applicant has been able to identify 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 land or sea reservoir type (called “GBS” meaning “Global Base Storage”).

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

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

When the storage facility 1 is positioned on a ship such as an LNG carrier, the supporting 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 wall of ceiling 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 chamfer walls (not shown) connecting the side walls to the bottom wall or to the ceiling wall 3. The walls of the tank 71 are thus connected to one another so as to form a polyhedral structure and to define 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 lines / unloading, not shown in the appended figures, to reach the bottom of the tank 71 by passing through this opening 10. The orifices necessary for these conduits in the liquid dome are in particular visible in FIG. 2 appended.

The storage installation 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 pipes of loading / unloading, 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 liquid dome cover 12, once the layout of the tank 71 has been carried out.

Thus, the storage installation 1 comprises a cover 12 arranged in the loading / unloading opening 10 in order to close the internal storage space at the level of said opening 10. The cover 12 includes access allowing the pipes. loading / unloading to pass through the cover 12 as well as two through 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 cover 12 also designates the "liquid dome". The loading / unloading opening 10 has a rectangular or square outline.

The 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 waterproofing membrane 17 resting against the secondary thermally insulating barrier 16, a primary thermally insulating barrier 18 comprising insulating elements, resting against the secondary waterproofing membrane 17 and a primary waterproofing membrane 19 intended to be in contact with the liquefied gas, in liquid or gaseous form, contained in tank 71.

[0065] According to one embodiment, the main structure of the tank 71 is conducted using the NO 96 ^® technology that is described in particular in document FR-A- 2867831. This document is incorporated herein by reference to describe arrangements of main structure 6, in particular at the level of elements 16, 17, 18 and 19.

The cover 12 has a multilayer structure comprising an upper cover wall 22, a lower cover wall 23 and a thermal insulation structure 24 disposed between these walls 22, 23. the lower wall of cover 23 comprises a plurality of flat metal plates assembled together in a sealed manner, including at least one main partition and two pairs of lateral 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 below, this connection is ensured by the lateral closure strips 60, 61. The upper wall of the cover 22 is fixed in a sealed manner to the internal bridge 3 all around the opening 10 so that it is the upper wall of the cover 22 which plays the part. role of secondary sealing membrane 17. The upper wall of cover 22 is produced using a metallic material, for example stainless steel.

The thermal insulation structure 24 comprises a plurality of thermal insulating 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 characteristics of mechanical strength that are superior, or even much superior, to so-called “non-structural” insulating elements 41. The structural insulating elements 40 may be blocks of foam. optionally fiber reinforced high density polymer or plywood or composite wood boxes filled with insulating padding (the latter inherently being non-structural thermal insulation) such as glass wool, polymer foam or perlite. The non-structural insulating elements 41 can be low density polymer foam blocks or glass wool. The expressions “structural insulating element” and “non-structural insulating element” refer to the fact that these elements have the mechanical properties described 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 mounting 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 opening 10. Once the cover 12 is in place in the opening 10, four lateral closure strips 60, 61 are positioned to ensure the sealed connection between the cover 12, more precisely the lower cover wall 23.

The lower cover wall 23, the lateral closure 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 the identical metal alloy of these three elements 23, 19 and 60, 61 makes it possible to facilitate their tight connection by welding. In the appended figures, the welds between different elements are illustrated schematically in Figures 6 and 8 appended by black triangles 20.

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

In the context of this invention, it is crucial to have adjacent to the lateral closure strip 60 adjacent to a structural thermal insulation 40, over the entire length where the mechanical attachment between the latter 40 and the strip 60 will be carried out . This aspect of arrangement of the structural thermal insulation 40 in contact with the lateral closure strip 60 appeared essentially 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 of, three elements: a central element 65 and two end elements 66. In this embodiment, only the central element 65 is mechanically fixed to the adjacent structural thermal insulation 40, the two end elements 66 being fixed in a sealed manner , by welding, to the central element 65. Advantageously, the dimensions - width, length, thickness - of the two end elements 66 are not strictly identical due to 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 - that is to say that fixed to the primary sealing membrane 19. The central element 65 advantageously has a length identical to that of the elements. end 66 but a width and a thickness which may differ slightly, of the order of a few millimeters for the width and of 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 fix the lateral 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 elements 66.

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

Once the mechanical means 68 in place and arranged as a function in each of the orifices 69, the orifice 69 is covered with a mechanical part 90 fixed in a leaktight manner to the lateral closure strip 60. Like of the first embodiment of the invention, at 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 in place and in operation in its dedicated orifice 69. It is also possible, as an alternative or in addition to this withdrawal 67, for the adjacent structural insulation 40 to include the same withdrawal having the same function with respect to the mechanical fixing means. FIG. 10 represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipe 76 and an onshore installation 77. The loading and unloading station 75 is a fixed off-shore installation comprising a movable arm 74 and a tower 78 which supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible hoses 79 which can be connected to the loading / unloading lines 73. The movable arm 74 can be swiveled and adapts to all types of LNG carrier templates. A connecting pipe, not shown, extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore installation 77. The latter comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the underwater pipe 76 to the loading or unloading station 75. The 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 are used. 75.

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 come within the scope of the invention.

The use of the verb "comprise", "understand" or "include" and 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 between parentheses cannot be interpreted as a limitation of the claim.

Claims

[Claim 1] Storage installation (1) for liquefied gas comprising a supporting structure (2) and a sealed and thermally insulating tank (71) arranged in the supporting 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 storage space, the main structure (6) comprising at least a waterproofing membrane (17, 19) and at least one thermally insulating barrier (16, 18), the thermally insulating barrier (16, 18) being placed between the waterproofing membrane (17, 19) and the supporting structure ( 2); the supporting structure (2) comprising a substantially planar upper supporting wall (3); the waterproofing 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 define a loading / unloading opening (10 ) intended to be crossed by fluid loading / unloading pipes; wherein the vessel (71) has a cover (12) disposed in the loading / unloading opening (10); wherein the cover (12) comprises an upper cover wall (22), a lower cover wall (23) and a thermal insulation structure (24), located between the lower cover wall (23) and the upper wall cover (22); in which the lower cover wall (23) comprises a plurality of flat metal plates assembled together in a sealed manner, including at least one main partition and two lateral closure 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 to a structural insulation (40) and in that said side closure strip (60) is mechanically attached to the adjacent structural insulation (40).

[Claim 2] A storage facility (1) according to claim 1, wherein the mechanical fastener (68) consists of a plurality of screwing, riveting or nailing, preferably a plurality of screwing.

[Claim 3] A storage installation (1) according to claim 1 or 2, wherein the lower cover wall (23), of which the main partition and the lateral closing bands (60, 61), is made of an iron alloy and nickel having a coefficient of thermal expansion of between 0.5.10 ⁶ and 2.10 6 K ^1, preferably the bottom wall of lid (23) is made of Invar ^®.

[Claim 4] Storage installation (1) according to one of claims 1 to 3, in which the flat metal plates of the lower cover wall (23) including at least the main partition and the lateral closure strips (60, 61) are fixed together by welding.

[Claim 5] 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.

[Claim 6] Storage installation (1) according to one of claims 1 to 5, wherein at least one lateral closure strip (60) consists of three elements, a central element (65) and two end elements ( 66), only the central element (65) being mechanically fixed to the adjacent structural insulation (40).

[Claim 7] A storage facility (1) according to claim 6, wherein the end members (66) sealably cover the mechanical attachment.

[Claim 8] A storage facility (1) according to claim 6 or 7, wherein the end members (66) are sealed to the central member (65).

[Claim 9] Storage installation (1) according to one of claims 6 to 8, wherein the central element (65) has a width of between 10 and 20 centimeters and the end elements (66) have a width between 8 and 15 centimeters.

[Claim 10] Storage installation (1) according to one of claims 1 to 5, in which at least one lateral closure strip (60) comprises a plurality of openings (69) for the mechanical connection by screwing with the adjacent structural insulation (40).

[Claim 11] A 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.

[Claim 12] 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 of a material identical to that of the lateral closure strip (60), fixed in a sealed manner, preferably by welding, to the lateral closure strip (60).

[Claim 13] A storage facility (1) according to any one of the preceding claims, wherein the thermal insulation structure (24) of the cover (12) and / or the structural insulation (40) adjacent to a side strip closure (60) consists of a plurality of boxes, preferably plywood, juxtaposed to each other and filled with an insulating lining.

[Claim 14] A storage facility (1) according to any one of the preceding claims, wherein the waterproofing membrane is a primary waterproofing membrane (19), the thermally insulating barrier is a primary thermally insulating barrier (18). and wherein the main structure (6) of the vessel (71) comprises, in a thickness direction from the exterior to the interior of the vessel (71), a secondary thermally insulating barrier (16) attached to the structure load-bearing, a secondary waterproofing membrane (17) carried by the secondary thermally insulating barrier (16), the primary thermally insulating barrier (18) being carried by the secondary waterproofing membrane (17), and the primary waterproofing membrane (19) carried by the primary thermally insulating barrier (18) being intended to be in contact with the liquefied gas.

[Claim 15] Ship (70) for the transport of a cold liquid product, the ship comprising a double hull (72) and a storage facility (1) according to one of claims 1 to 14 arranged in the double hull.

[Claim 16] A vessel (70) according to claim 15, wherein the vessel (70) has an inner deck (4) and an outer deck (5), an inner upper load-bearing wall (4) of the load-bearing structure being formed by the inner bridge (4) and an outer upper load-bearing wall (5) being formed by the outer bridge (5).

[Claim 17] A 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 vessel ( 71) installed in the hull of the ship at an external floating or onshore storage facility (77) and a pump for driving a flow of cold liquid product through insulated pipelines from or to the external floating or onshore storage facility to or from the vessel's tank.

[Claim 18] A method of loading or unloading a ship (70) according to claim 15 or claim 16, wherein 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 of the vessel (71).