CN115698580A

CN115698580A - Liquid dome for a storage tank for liquefied gas

Info

Publication number: CN115698580A
Application number: CN202180036951.2A
Authority: CN
Inventors: 朱利安·库托; 爱德华·迪克卢瓦
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2020-05-20
Filing date: 2021-05-19
Publication date: 2023-02-03
Also published as: KR20230008186A; WO2021233986A1; FR3110667B1; JP2023526089A; FR3110667A1

Abstract

The invention relates to a storage unit (1) for liquefied gas and a sealed and insulated tank (71) comprising a loading/unloading opening (10) having an upper lid wall (23), a lower lid wall (22) and an insulating structure (24) between the lower lid wall (22) and the upper lid wall (23), a pipe (30) and the upper lid wall (23) being made of iron-based alloys of different types, and at least one attachment lug (50) extending from the upper lid wall (23) being directly or indirectly attached to the lower lid wall (22) in a sealed manner.

Description

Liquid dome for a storage tank for liquefied gas

Technical Field

The present invention relates to the field of storage facilities for liquefied gases, which storage facilities comprise sealed insulated membrane tanks. In particular, the present invention relates to the field of sealed and insulated tanks for storing and/or transporting liquefied gases at cryogenic temperatures, such as tanks for transporting liquefied petroleum gas (also called LPG), for example at temperatures between-50 ℃ and 0 ℃, or tanks for transporting Liquefied Natural Gas (LNG) at atmospheric pressure of about-162 ℃. These tanks may be installed onshore or on a floating structure. In the case of a floating structure, the tank may be used to transport or receive liquefied gas, which is used as fuel to propel the floating structure.

Background

Document FR2991430 describes a storage device for liquefied gas comprising a sealed and insulated tank integrated into a load-bearing structure constituted by a double hull of a ship. Each wall of the tank includes a secondary insulating barrier, a secondary sealing membrane, a primary insulating barrier, and a primary sealing membrane.

In the region of the top of the tank, the tank has a projection in the form of a chimney, known as a liquid dome. In this region, the load-bearing structure is locally interrupted to delimit a loading/unloading opening through which the fluid loading/unloading duct is intended to pass. The loading/unloading opening (called liquid dome) comprises an insulating or heat-insulating barrier and an element forming a main sealing membrane.

It is desirable to reduce the production costs associated with producing such liquid domes, particularly by using less expensive materials, but the characteristics of these materials are less suitable for the very low temperatures encountered by the tank and such liquid domes. Furthermore, the tank is installed in a structure (such as a ship) which is subjected to very high mechanical stresses, which twist and bend according to the environmental conditions of the structure, these mechanical loads being particularly disadvantageous for the structure of the liquid dome which extends vertically above the tank filled with liquefied gas in the manner of a relatively narrow chimney.

After various experiments and tests, the applicant has found that it is possible to envisage a liquid dome tube made of a relatively inexpensive metal material, provided that a specific structure is created so that the liquid dome can withstand the great stresses that the liquid dome must absorb.

The applicant first intends to propose a liquid dome that is less expensive but able to withstand all the stresses to which it is subjected, while providing a perfect seal, both physically and thermally, against the extremely cold fluid contained in the tank.

Disclosure of Invention

The invention therefore relates to a storage plant for liquefied gas, comprising a load-bearing structure and a sealed and thermally insulated tank arranged in the load-bearing structure, the sealed and thermally insulated tank comprising a main structure formed by a plurality of tank walls connected to each other and fixed to the load-bearing structure, the main structure defining an internal storage space, the main structure comprising at least one sealing membrane and at least one thermally insulating barrier layer, the thermally insulating barrier layer being placed between the sealing membrane and the load-bearing structure; the load bearing structure includes a generally planar upper load bearing wall; the sealing membrane, the insulating barrier of the main structure and the upper load-bearing wall are partially interrupted to delimit a duct forming the load-bearing wall of the drum extending along the vertical axis to an upper end containing a loading/unloading opening intended for the passage therethrough of the fluid loading/unloading duct, wherein the tank comprises a lid placed in the loading/unloading opening, and wherein the lid comprises an upper lid wall, a lower lid wall and an insulating structure located between the lower lid wall and the upper lid wall.

The invention is characterized in that the above-mentioned pipe and the upper lid wall are made of iron-based alloys of different nature, and at least one fixing tab originating from the upper lid wall is fixed in a sealing manner directly or indirectly to the lower lid wall.

Thus, after a number of tests and analyses, the applicant found that it was possible to use a pipe made of inexpensive carbon steel, provided that a special arrangement was made to firmly anchor the lower lid wall forming the main membrane to the opening of the liquid dome, while leaving a certain degree of freedom to absorb thermal expansions.

By doing so, the invention enables a substantial saving to be achieved in the production of liquid domes, while ensuring or maintaining an effective seal against the liquefied gas and excellent mechanical resilience of the dome against all stresses to which the dome is normally subjected.

The term "conduit" is understood to mean a conduit forming the outer wall of the liquid dome, more specifically the wall of the cylinder forming the opening to the tank containing the liquefied gas.

By convention, the terms "outer" and "inner" are used to define the relative position of one element with respect to another with reference to the interior and exterior of the tank.

Other advantageous features of the invention are briefly described below:

advantageously, the fixing tab has an L-shaped cross section and comprises a linear proximal portion originating from the upper lid wall, which is elongated by a distal portion starting from the proximal portion at an angle of 90 ° ± 10 °.

Advantageously, the thermal insulation barrier is a secondary thermal insulation barrier and the sealing membrane comprises, in succession from the inside of the tank towards the duct, a primary sealing membrane and a secondary sealing membrane, the primary thermal insulation barrier being placed between the primary sealing membrane and the secondary sealing membrane and the fixing tab also being fixed in a sealed manner to the secondary sealing membrane.

The fixing tab is therefore connected not only in a sealing manner to the lower lid wall (which forms the main membrane of the opening of the liquid dome), but also to the heat-insulating sealing structure (secondary sealing membrane in this example). This arrangement enables a firm and flexible fixation of the main structure of the tank on the one hand, and of the lower lid wall (which forms the main membrane of the opening of the liquid dome) on the other hand, to the upper lid wall, which, like the fixing tabs, is made of a material that is particularly strong from a mechanical point of view and has a very low coefficient of thermal expansion.

According to a preferred embodiment, the fixing of the fixing tab to the secondary sealing membrane is performed at the distal portion of the fixing tab.

According to a preferred embodiment of the invention, the fixing of the fixing tab to the secondary sealing film is achieved by gluing.

According to another embodiment, it is also possible to envisage using welding to achieve this fixing, in particular in the case where the secondary sealing film is metal or a material that can be assembled with a metal material. In this case, the fixing of the fixing tab to the secondary sealing film is effected using a sealing weld.

According to one embodiment of the invention, the fixation is achieved by welding at the proximal part of the fixation tab, when the fixation tab is directly fixed to the lower lid wall.

In this case, the main sealing membrane is advantageously fixed in a sealed manner, preferably by welding, to the lower lid wall.

According to one embodiment of the invention, the connecting piece connects the lower lid wall, the sealing membrane and the fixing tab in a sealing manner when the fixing tab is indirectly fixed to the lower lid wall.

In this case, preferably, the fixing tab has a flange which originates from the proximal end portion and extends at an angle of 90 ° ± 10 ° with respect to the proximal end portion, the connecting piece being fixed to the flange of the fixing tab.

Advantageously, the pipe is made of carbon steel. The pipe is thus made of an iron-based alloy and contains 0% < C < 2.11% by weight. Preferably, the carbon content may be included in the range 0% < C < 0.8%, more particularly 0% < C < 0.5%, depending on the weldability properties sought.

The carbon steel may include other elements in its composition. The sum of these elements is preferably less than or equal to 5%, so that the steel is lightly alloyed. Thus, the carbon steel may also contain 0% < Mn < 2%,0% < Si < 0.5% by weight.

According to one embodiment, the pipe is made of an iron-based alloy of the type containing, by weight, 0% < C < 0.21%, 0% < Mn < 1%, 0% < Si < 0.5%, 0% < P < 0.035%, and 0% < S < 0.035%, the remainder being iron and impurities inevitably resulting from the production of iron.

Preferably, the piping is made from grade A, B, D, AH, DH, EH, FH or E steel in accordance with the IGC code, which is known to those skilled in the art as International code for construction and equipment of bulk transport liquefied gas vessels.

Advantageously, the upper lid wall and the fixing tabs are made of an iron-based alloy comprising an austenitic steel containing, by weight, 0 < C < 0.08%,0% < Mn < 2%,0% < Si < 0.5%, 0% < P < 0.045%, 0% < S < 0.030%, 8% < Ni < 14%, 16% < Cr < 50%, 0% < N < 0.02%, optionally 0% < Mo < 3% and/or 0% < Ti < 0.7%, the remainder being iron and impurities inevitably resulting from the production of iron.

Conventionally, consider elements in the periodic table of elements, namely:

c: carbon; cr: manganese; cr: chromium; si: silicon; ni: nickel; co: cobalt; p: phosphorus; o: oxygen; n: nitrogen; mo: molybdenum; s: sulfur and Ti: titanium.

Advantageously, the lower lid wall comprises:

-a plurality of planar metal plates assembled to each other, the planar metal plates having a coefficient of thermal expansion comprised between 0.5.10 ^-6 K ^-1 To 2.10 ^-6 K ^-1 Made of an iron-nickel alloy therebetween, or

-a plurality of corrugated metal sheets juxtaposed in a repeating pattern and welded together in a sealed manner, the metal sheets being made of stainless steel. It is noted here that the corrugated metal sheets may be made of high manganese steel, the term "stainless steel" including such alloys.

Thus, the lower lid wall may have undulations similar to those visible on the main membrane of the main structure in fig. 3 and 4 and intended to provide mechanical integrity when the metal from which the sheet is made expands due to very cold temperatures in the tank, or the lower lid wall may comprise a plate with a very low coefficient of thermal expansion, for example made of invar

And (4) preparing.

The invention relates to a vessel for transporting cold liquid products, having a double hull and a storage facility as described above, which is arranged in the double hull.

The invention also relates to a system for delivering a cold liquid product, comprising: a vessel as hereinbefore described; an isolation piping assembly arranged in such a manner as to connect a tank installed in a hull of a ship to an external storage facility on a floating or shore; and a pump for delivering the cold liquid product stream from the floating or onshore external storage facility to the vessel's tank, or from the vessel's tank to the floating or onshore external storage facility, through the isolation piping assembly.

Finally, the invention relates to a method of loading or unloading from a marine vessel as described above, wherein cold liquid product is transferred from or from a tank of the marine vessel to a tank of the marine vessel through an insulated pipe assembly.

Drawings

The invention will be better understood and other objects, details, characteristics and advantages thereof will become more apparent from the following description of several particular embodiments of the invention, given by way of non-limiting illustration only, with reference to the accompanying drawings.

Fig. 1 is a schematic cross-sectional view of a liquid dome according to an embodiment of the present invention.

Fig. 2 is an enlarged view of a corner portion of fig. 1.

Fig. 3 is a schematic diagram showing a first angular view of the elements of the liquid dome shown in fig. 1.

Fig. 4 is a schematic diagram showing a second angular view of the elements of the liquid dome shown in fig. 1.

Fig. 5 is a schematic cross-sectional view of the same portion of a liquid dome of fig. 2 according to another embodiment of the invention.

Fig. 6 is a schematic cross-sectional view of the same portion of a liquid dome according to yet another embodiment of the invention as the liquid dome of fig. 2.

Fig. 7 is a schematic cross-sectional view of the storage facility of the methane carrier and a terminal for loading/unloading from the tank.

Detailed Description

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

When the storage arrangement 1 is positioned on a vessel, such as a methane transport vessel, the load bearing structure (not shown in the drawings) is formed by the double hull of the vessel. The outer upper load bearing wall 5 is called the outer deck 5 of the vessel.

The tank 71 has: a main structure formed by a bottom wall (not shown), a top wall and two cofferdam walls (not shown in the figures) connecting the bottom wall to the top wall and located at the front and rear when the storage facility 1 is located on board the vessel; two side walls (not shown); and optionally two to four chamfered walls (not shown) connecting the side walls to the bottom or top wall, not shown in the drawings. Thus, the walls of the tank 71 are connected to each other to form a polyhedral structure and to define the internal storage space 9.

For loading and unloading liquefied gas into and from the tank 71, the storage facility 1 has a loading/unloading opening 10 which partially interrupts the outer upper load-bearing wall 5, the inner upper load-bearing wall and the top wall of the tank 71, so that in particular a loading/unloading pipe (not shown in the figures) can reach the bottom of the tank 71 through this opening 10.

The storage facility 1 also comprises a loading/unloading tower (not shown in the figures) positioned according to the opening 10 and located inside the tank 71, which forms a support structure for the pump (not shown) and for the loading/unloading pipe over the entire height of the tank 71.

Furthermore, the storage device 1 has a cover 12 which is arranged in the loading/unloading opening 10 to close the inner storage space at said opening 10. The cover 12 has an aperture that enables a loading/unloading pipe to pass through the cover 12.

Tank 71 comprises a drum 15 which is located on the main structure at the opening and which enables the tank walls to extend continuously from the inner deck to the outer deck 5, which decks are interrupted by the loading/unloading opening 10. In the case of a liquefied gas storage tank, such a cylinder 15 fitted with said lid 12 is called a liquid dome.

The loading/unloading opening 10 and the drum 15 have a generally rectangular profile. Thus, the drum 15 comprises four walls, one wall being a continuation of the rear cofferdam wall 8 (as shown in fig. 1) and the other three walls being connected to the top wall so as to be at an angle of 90 ° to the latter.

In the context of the present invention, the lid 12 is located at the outer deck 5, that is to say such that the lid closes or encloses the drum 15. The tank 71 is a membrane tank 71 capable of storing liquefied gas. The main structure of the tank 71 comprises a multilayer structure having, from the outside to the inside: a secondary thermal barrier layer 16 having insulating elements, the secondary thermal barrier layer abutting the load bearing structure; a secondary sealing film 17, which abuts the secondary insulating barrier 16; a primary thermal barrier layer 18 with insulating elements, which is against the secondary sealing film 17; and a primary sealing membrane 19 intended to come into contact with the liquefied gas contained in the tank 71.

According to one embodiment, the main structure of the tank 71 is according to Mark (Mark)

The production of the technique, which is described in particular in document FR-A-2691520.

In this primary structure, the secondary thermal barrier 16, the primary thermal barrier and the secondary sealing film 17 essentially consist of panels juxtaposed on a load bearing structure, which may be an internal load bearing structure or a structure connecting the internal upper load bearing wall to the external upper load bearing wall 5 at the opening 10. The secondary sealing membrane 17 is formed of a composite material comprising an aluminium sheet sandwiched between two sheets of glass fibre fabric. The primary sealing membrane 19 is obtained, in part, by assembling a plurality of metal plates welded to one another along their edges and comprising undulations extending in two mutually perpendicular directions. The metal plate is made of, for example, a stainless steel sheet or an aluminum sheet, and is formed by bending or pressing. The main sealing film 19 is shown in particular in fig. 3 and 4.

Further details of such a corrugated metal film are described in particular in FR-a-2861060.

In the barrel 15, the secondary sealing membrane 17 is fixed at its upper end to a fixing tab 50, more specifically at a distal portion 51 of said tab 50. Advantageously, the connection between the fixing tab 50 and the secondary membrane 17 is made by means of sealing adhesion (collage), possibly by welding.

The lid 12 further comprises a multi-layered structure comprising, from the outside to the inside, an upper lid wall 23, a lower lid wall 22 and an insulating structure 24 located between the lower lid wall 22 and the upper lid wall 23. The lid 12 also comprises a reinforcement 25, which is located on the upper lid wall 23.

The cover 12 is placed in the loading/unloading opening 10 in such a way that the upper cover wall 23 is positioned in the plane of the outer upper load-bearing wall 5 or the outer deck 5. Thus, in this example, the storage device 1 does not have a dome and the lid 12 does not protrude above the outer deck 5.

The upper lid wall 23 is fixed to the outer deck 5 around the opening 10 in a sealed manner, so that the upper lid wall 23 functions as a secondary sealing membrane 17 in the case of the lid 12. The upper lid wall 23 is produced using a metallic material, such as stainless steel.

The lower lid wall 22 is welded in a sealed manner to the main sealing membrane 19 of the main structure, in this example the drum 15, using a connection 26. The connector 26 is depicted in greater detail in fig. 2-5, according to various embodiments of the present invention. The lower cover wall 22 is also welded in particular in a sealed manner to the loading/unloading duct.

The insulating structure 24 of the lid 12 comprises a plurality of insulating elements, which are juxtaposed to one another and may have similar or different configurations. In a preferred embodiment, the insulating elements positioned according to the lower lid wall 22 and the connecting piece 22 are structural insulating elements, while the insulating elements located at the periphery of the insulating structure 24 are non-structural insulating elements. The structural insulating element may include: a block of high density polymeric foam, optionally reinforced with fibers; or boxes made of plywood or composites, filled with insulating filler (such as glass wool or perlite). The non-structural insulating elements may be low density polymer foam blocks or glass wool blocks.

A securing tab 50 originates from the upper lid wall 23 and extends vertically, the securing tab having a vertical proximal portion 51 and a distal portion 52 that extends horizontally or forms a C-hook. Advantageously, therefore, the fixing tab 15 is made of the same material as that of the upper cover wall 23. The fixing tab 50 is therefore made of a metallic material (typically an iron-based alloy) having better mechanical integrity when the ambient temperature is substantially lower than 0 ℃, or even lower than or equal to-40 ℃.

Thus, the upper lid wall 23 and the securing tab 50 may be constructed of 300 series stainless steel as mandated by the IGC code. In other words, the fixing tab 50 is made of austenitic steel according to the ASTM a240 standard.

The invention resides above all in the fact that, thanks to the presence of the fixing tabs 50, the duct 30 is produced from steel called carbon steel (in particular, steel comprising grades a, B, D, AH, DH, EH, FH or E according to the ASTM a131 standard), this duct 30 forming the cylinder 15 of the liquid dome. This grade of steel is less robust or elastic when the ambient temperature drops significantly below 0 ℃, which indicates that there may be or even some risk in the liquefied gas tank, but these steels are much cheaper than stainless steel.

This arrangement thus makes it possible to reduce the amount of expensive stainless steel in the liquid dome and to impart flexibility to the primary anchor point (that is to say, the anchor point anchored to the lower lid wall 22 forming the primary membrane at the opening 10 of the liquid dome and to the primary membrane 19) and the secondary anchor point (that is to say, the anchor point anchored to the secondary membrane 17).

Thus, a primary key aspect of the present invention is to connect and secure the lower lid wall 22 to the securing tab 50. Furthermore, the fixing tab is offset at least a few centimeters with respect to the duct 30 of the barrel 15 of the liquid dome, that is to say it is placed at a distance of between 5 and 35 centimeters from the duct, preferably between 15 and 25 centimeters. This offset of the fixing tabs 50 with respect to the duct 30 causes a flexible fixing of the lower cover wall 22, so that the assembly can easily absorb large mechanical stresses, it being noted that, when the structure containing the tank 71 is a boat, the area of the drum 15 of the liquid dome is much smaller or narrower than the tank 71 due to the size of the area of the drum and high mechanical stresses and tensions are concentrated due to the vertical position of the area of the drum.

As can be seen in the figures, the offset of the fixing tabs 50 with respect to the duct 30 makes it possible to reduce the use of structural insulation 40, which is more expensive and difficult to arrange than other non-structural insulation 41. Thus, in a liquid dome structure according to the present invention, the amount of structural insulation 40 may be somewhat reduced as compared to a conventional liquid dome without the securing tabs 50.

A second aspect of the invention is that the securing tab may be connected directly or indirectly to the lower lid wall 22. Thus, as shown in fig. 1-5, the connector 26 may be used when such fixation is indirect, while one embodiment is shown in fig. 6 when the fixation is direct.

As can be seen in fig. 1 to 5, the connecting piece 26 comprises: a first flange 27 welded in a sealed manner to the primary sealing membrane 19 of the primary structure; a second flange 28 connected to the first flange 27 and welded to the lower lid wall 22 in a sealed manner around the lower lid wall 22; and a third flange 29 connected to a flange 53 extending horizontally from the proximal portion 51. The flange 53 originates from the fixing tab 50 and is advantageously made of the same material as these

portions

51, 52.

Figures 3 and 4 show optional supplementary elements of the liquid dome according to the invention. These figures particularly show the undulations 60 which are present on the primary membrane 19 of the primary structure of the tank 71. These undulations 60 enable the primary membrane 19 to withstand thermal expansion of the membrane 19 when the tank 71 is filled with liquefied gas at very low temperatures, well below 0 ℃.

In this example, the distal portion 52 has an inverted C-shaped cross-section, such that a portion of the distal portion 52 is fixed to the secondary membrane 17 by welding, while another portion of the distal portion 52 is in contact with the secondary thermal barrier 16 and limits the space of the barrier 16 in the barrel 15.

The flange 53 of the fixing tab 50 extends horizontally, that is to say at an angle of 90 ° ± 10 ° with respect to the proximal portion 51, to access the connection 26 or directly to the lower lid wall 22, the latter embodiment (in which the connection 26 is absent, but with the flange 53 projecting from the proximal portion 51) not being shown in the drawings, but being conceivable within the scope of the invention.

Fig. 5 depicts an embodiment of the present invention wherein the essential difference is that there is no flange 53 from proximal portion 51. In such an embodiment, the flange 29 of the connector 26 is extended until it comes into abutment with the proximal portion 51 of the fixing tab 50. As with the other embodiments, this flange 29 of the connector 26 is fixed to the proximal portion 51 of the fixing tab 50 by means of a sealing weld. Thus, in this embodiment, the flange 29 of the connector 26 is much longer than in the other embodiments, and the flange 29 herein typically has a length of at least fifteen centimeters, preferably about twenty centimeters.

Fig. 6 shows an embodiment in which there is no connector 26, so the fixation between the fixation tab 50 and the lower lid wall 22 is referred to as a "direct" fixation. Thus, in this embodiment, the flange 53 of the securing tab 50 extends until it meets and secures the lower lid wall 22, otherwise, as shown in fig. 6, the lower lid wall 22 extends until it comes into abutment with the securing tab 50. In any of these embodiments, the securing of the securing tab 50 and the lower lid wall 22 together without the connector 26 is performed in a sealed manner, preferably using welding.

In the embodiment of fig. 6, the main membrane 19 of the main structure has a flat 19', that is to say an L-shaped end portion, at the end of the main membrane, which flat bears on the lower lid wall 22 or abuts against the lower lid wall 22, so that the welded connection between the lower lid wall 22 and the main membrane 19 is completely sealed. Other features of the invention are not distinguished in their variants from features previously described in the context of other embodiments.

Figure 7 shows an example of a marine terminal comprising a loading and unloading station 75, a subsea pipeline 76 and an onshore facility 77. The loading and unloading station 75 is a fixed offshore facility that includes a mobile arm 74 and a tower 78 that supports the mobile arm 74. The moving arm 74 carries a bundle of insulated flexible hoses 79 that can be connected to the loading/unloading duct assembly 73. The orientable moving arm 74 is suitable for all sizes of methane carrier. Connecting piping (not shown) extends within the tower 78. The loading and unloading station 75 enables loading and unloading from the methane transport vessel 70 to an onshore facility 77 or from an onshore facility to a methane transport vessel. The onshore facility has a liquefied gas storage tank 80 and a connecting pipeline 81 which is connected to the loading or unloading station 75 by a submarine pipeline 76. The underwater pipelines 76 enable the liquefied gas to be transported over long distances (e.g., 5 km) between the loading or unloading station 75 and the onshore facility 77, thereby enabling the methane carrier 70 to remain a long distance away from shore during loading and unloading operations.

In order to generate the pressure required for the transportation of the liquefied gas, pumps carried on board the vessel 70 and/or provided with onshore equipment 77 and/or provided with loading and unloading stations 75 are used.

Although the invention has been described in connection with a number of specific embodiments, it is obvious that the invention is not restricted thereto, and that it comprises all technical equivalents of the means described and combinations thereof, if these are within the scope of the invention.

Use of the verb "comprise", "exhibit" or "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Claims

1. A storage arrangement (1) for liquefied gas, comprising a load bearing structure and a sealed and insulated tank (71) arranged in the load bearing structure,

the sealed insulated tank (71) comprising a main structure formed by a plurality of tank walls connected to each other and fixed to the load-bearing structure, the main structure defining an internal storage space, the main structure comprising at least one sealing membrane (17, 19) and at least one insulating barrier (16, 18), the insulating barrier (16, 18) being placed between the sealing membrane (17, 19) and the load-bearing structure;

the load bearing structure includes a generally planar upper load bearing wall;

the sealing membranes (17, 19), the thermal barrier layer (16, 18) of the main structure and the upper load-bearing wall being partially interrupted so as to define a duct (30) forming a load-bearing wall of a drum (15) extending along a vertical axis to an upper end containing a loading/unloading opening (10) intended for the passage of a fluid loading/unloading duct through the loading/unloading opening, wherein the tank (71) comprises a lid (12) placed in the loading/unloading opening (10), and wherein the lid (12) comprises an upper lid wall (23), a lower lid wall (22) and an insulating structure (24) located between the lower lid wall (22) and the upper lid wall (23),

characterized in that the pipe (30) and the upper cap wall (23) are made of iron-based alloys of different nature, and at least one fixing tab (50) originating from the upper cap wall (23) is fixed in a sealing manner directly or indirectly to the lower cap wall (22).

2. Storage device (1) according to claim 1, wherein the fixing tab (50) has an L-shaped cross-section and comprises a linear proximal portion (51) originating from the upper lid wall (23) and prolonged by a distal portion (52) starting from the proximal portion (51) at an angle of 90 ° ± 10 °.

3. Storage device (1) according to claim 1 or 2, wherein the thermal insulation barrier is a secondary thermal insulation barrier (16) and the sealing membranes (17, 19) comprise in succession, from the inside of the tank (71) towards the duct, a primary sealing membrane (19) and a secondary sealing membrane (17), a primary thermal insulation barrier (18) being placed between the primary sealing membrane (19) and the secondary sealing membrane (17), and wherein the fixing tab (50) is also fixed in a sealed manner to the secondary sealing membrane (17).

4. Storage device (1) according to claims 2 and 3, wherein the fixing of the fixing tab (50) to the secondary sealing membrane (17) is performed at the distal end portion (52) of the fixing tab (50).

5. Storage device (1) according to claim 3 or 4, wherein the fixing of the fixing tab (50) to the secondary sealing film (17) is achieved by gluing.

6. Storage device (1) according to one of claims 1 to 5 considered in connection with claim 2, wherein the fixation is achieved by welding at the proximal end portion (51) of the fixation tab (50) when the fixation tab (50) is directly fixed to the lower lid wall (22).

7. Storage device (1) according to one of claims 1 to 6, considered in connection with claim 3, wherein the primary sealing membrane (19) is fixed in a sealed manner to the lower lid wall (22), preferably by welding.

8. Storage device (1) according to one of claims 1 to 5, wherein a connection (26) connects the lower lid wall (22), the sealing membrane (19) and the fixing tab (50) in a sealing manner when the fixing tab (50) is indirectly fixed to the lower lid wall (22).

9. Storage device (1) according to claims 2 and 8, wherein the fixing tab (50) comprises a flange (53) originating from the proximal portion (51) and extending at an angle of 90 ° ± 10 ° with respect to the proximal portion (51), the connector (26) being fixed to the flange (53) of the fixing tab (50).

10. Storage device (1) according to any of the preceding claims, wherein the pipe (30) is made of carbon steel, and preferably the pipe (30) is made of an iron-based alloy containing 0% < C < 2.11% by weight.

11. The storage facility (1) according to claim 10, wherein the piping (30) is made of a steel of grade a, B, D, AH, DH, EH, FH or E according to IGC specifications.

12. The storage device (1) according to any one of the preceding claims, wherein the upper lid wall (23) and the fixing tabs (50) are made of an iron-based alloy comprising an austenitic steel containing, by weight, 0 < C < 0.08%,0% < Mn < 2%,0% < Si < 0.5%, 0% < P < 0.045%, 0% < S < 0.030%, 8% < Ni < 14%, 16% < Cr < 50%, 0% < N < 0.02%, and optionally 0% < Mo < 3% and/or 0% < Ti < 0.7%, the remainder being iron and impurities inevitably resulting from the production of iron.

13. The storage device (1) according to any one of the preceding claims, wherein the lower lid wall (22) comprises:

-a plurality of planar metal plates assembled to each other, said planar metal plates having a coefficient of thermal expansion comprised between 0.5.10 ^-6 K ^-1 To 2.10 ^-6 K ^-1 Made of an iron-nickel alloy therebetween, or

-a plurality of corrugated metal sheets juxtaposed in a repeating pattern and welded together in a sealed manner, said metal sheets being made of stainless steel.

14. Vessel (70) for transporting cold liquid products, having a double hull (72) and a storage device (1) according to one of claims 1 to 13, which storage device is arranged in the double hull.

15. A delivery system for delivering a cold liquid product, the system comprising: the vessel (70) of claim 14; an insulated pipe assembly (73, 79, 76, 81) arranged in such a way as to connect the tank (71) mounted in the hull of the vessel to a floating or onshore external storage facility (77); and a pump for delivering a flow of cold liquid product from the floating or onshore external storage facility to the tank of the vessel or from the tank of the vessel to the floating or onshore external storage facility through the insulated piping assembly.

16. A method for loading or unloading from a vessel (70) according to claim 14, wherein cold liquid product is transported from a floating or on-shore external storage facility (77) to the tank of the vessel (71) or from the tank of the vessel to a floating or on-shore external storage facility through an insulated pipe assembly (73, 79, 76, 81).