EP3824216A1

EP3824216A1 - Fluid-storage facility

Info

Publication number: EP3824216A1
Application number: EP19756227.5A
Authority: EP
Inventors: Emmanuel HIVERT; Christophe LECONTE; Pierre Charbonnier; Mohammed OULALITE; Jean-Damien CAPDEVILLE; Geoffrey DETAILLE
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2018-07-16
Filing date: 2019-07-12
Publication date: 2021-05-26
Also published as: JP7419338B2; WO2020016509A1; SG11202100409QA; FR3083843A1; US20210293384A1; FR3083843B1; JP2021530412A; US11649930B2; KR20210031950A; CN112424525B; CN112424525A

Abstract

The invention relates to a fluid-storage facility, the storage facility comprising a supporting structure (1) and a tank, the tank including at least one tank bottom wall attached to the supporting structure (1), wherein the bottom wall includes a structure with multiple layers superimposed in a thickness direction including at least one waterproofing membrane and at least one thermal insulation barrier arranged between the waterproofing membrane and the supporting structure (1), wherein the bottom wall includes a sump structure (9) including a rigid container (10, 11) comprising a side wall (12), the container (10, 11) being arranged through the thickness of the bottom wall, and the sump structure (9) comprising at least one attachment means (15) arranged to attach the rigid container (11) to the supporting structure (1) at an attachment point, and wherein the at least one attachment means (15) is configured to allow the relative movement of the side wall (12) of the container (11) with respect to the supporting structure (1) in a transverse direction perpendicular to the side wall (12) at the attachment point of the container (11).

Description

Fluid storage facility

Technical area

The invention relates to the field of fluid storage installations comprising a sealed and thermally insulating tank with a membrane. In particular, the invention relates in particular to installations for the storage and / or transport of liquefied gas at low temperature, such as Liquefied Petroleum Gas (also called LPG) having for example a temperature between -50 ° C and 0 ° C, or Liquefied Natural Gas (LNG) at around -162 ° C at atmospheric pressure. These installations can be installed on land or on a floating structure. In the case of a floating structure, the tank of the storage installation can be intended for the transport of liquefied gas or to receive liquefied gas serving as fuel for the propulsion of the floating structure.

Technological background

Fluid storage installations are known for example in document WO2016 / 001 142. Such a storage installation comprises a load-bearing structure, for example the internal hull of a ship, and a sealed and thermally insulating tank located at the inside of the supporting structure and fixed to it. The waterproof and thermally insulating tank has a multilayer structure superimposed in a thickness direction comprising a waterproofing membrane and a thermally insulating barrier disposed between the waterproofing membrane and the support structure.

In order to maximize the operating efficiency of such a tank, it is desirable to optimize the useful volume of cargo that it is possible to load into the tank and unload from the tank. The use of an unloading pump sucking the liquid towards the top of the tank means that a certain height of liquid has to be kept at the bottom of the tank, failing which the suction member of the pump enters into communication with the gas phase. , which deactivates and / or degrades the pump. This is why it is known to produce a sump structure on the bottom wall of such a tank locally interrupting the sealing membrane, the sump structure comprising a container sinking through the bottom wall of the tank. so that the liquid in the container is at the lowest level of the tank. The unloading pump is therefore placed in such a sump structure which makes it possible to maximize the operating efficiency of the tank.

However, during the loading of the tank with a cryogenic fluid such as LNG, the elements of the tank directly in contact with the fluid like the sump structure are subjected to a strong temperature variation which has the consequence of contracting them thermally. . However, the sump structure is fixed to the supporting structure which is not in contact with the cryogenic fluid. The fixing means making it possible to fix the sump structure to the support structure could therefore be subjected to high mechanical stresses which can accelerate the fatigue of the materials and limit the operating time of the tank.

It is also known, in particular from document JP2000168885, to use a sump structure in land-based storage facilities of the underground type whose supporting structure is made of concrete. In this type of installation, the sump structure is not fixed to the support structure but simply placed on the support structure. Indeed, in this type of installation, no movement of fluid is to be expected unlike storage in floating structures, it is therefore possible not to fix the sump structure. However, this design is not compatible with all applications.

In addition, mechanical stresses linked to this application consisting in the production of a sump in the sealed and thermally insulating tank are to be taken into account by a person skilled in the art.

summary

An idea underlying the invention is to improve the fixing between the sump structure and the supporting structure to increase its service life and reliability.

According to one embodiment, the invention provides a fluid storage installation, the storage installation comprising a support structure and a sealed and thermally insulating tank, the tank comprising at least one bottom wall fixed to the support structure, in the bottom wall of which has a multilayer structure superimposed in a thickness direction including at least one waterproofing membrane and at least one thermal insulation barrier disposed between the waterproofing membrane and the support structure, in which the bottom wall comprises a sump structure locally interrupting the waterproofing membrane of the bottom wall, the sump structure comprising a rigid container having a side wall, the container being arranged through the thickness of the wall bottom, and the sump structure comprising at least one fixing means designed to fix the rigid container to the carrying structure at a fixing point of the side wall,

and wherein the at least one fixing means is configured to allow relative movement of the side wall of the container relative to the support structure in a transverse direction perpendicular to the side wall at the point of fixing of the container, the relative movement being greater than 1 mm, for example between 1 and 5 mm.

The expression "in a transverse direction perpendicular to the side wall at the point of attachment" means the direction orthogonal to the tangent plane of the side wall at the point of attachment.

Also, the expression “attachment point of the side wall” refers, according to all the embodiments, to the location of attachment of the attachment means to the sump structure, at the level of the side wall of the latter.

Thus, the at least one fixing means makes it possible to fix the sump structure to the support structure while allowing the side wall of the container of the sump structure to be able to move relatively relative to the support structure in the transverse direction. The sump structure can thus contract thermally while remaining fixed to the supporting structure and preventing the at least one fixing means from being subjected to excessive mechanical stresses.

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

According to one embodiment, the at least one fixing means comprises a first portion fixed, preferably welded, to the support structure and a second portion fixed, preferably welded to the side wall of the container.

According to one embodiment, the at least one fixing means is fixed directly, preferably welded directly, to the support structure. According to one embodiment, the at least one fixing means is fixed directly, preferably welded directly, to the side wall of the container.

According to one embodiment, the support structure is made of a metallic material.

According to one embodiment, the support structure is a portion of the hull of a floating structure.

According to one embodiment, the at least one fixing means is located between the sealing membrane and the support structure in the thickness direction.

According to one embodiment, the sump structure comprises a fixing wing fixed in a sealed manner, that is to say forming a closed surface that does not allow the fluid, for example welded, to pass to the sealing membrane.

According to one embodiment, the at least one fixing means is at least partially located under the fixing wing in the thickness direction.

According to one embodiment, the waterproofing membrane is a secondary waterproofing membrane, the thermally insulating barrier is a secondary thermally insulating barrier, the fixing wing is a second fixing wing, in which the bottom wall comprises a primary thermally insulating barrier located on the secondary sealing membrane and also comprises a primary sealing membrane located on the primary thermally insulating barrier, and in which the sump structure comprises a first fixing wing fixed in a sealed manner, this is that is to say forming a closed surface which does not allow the fluid, for example welded, to pass to the primary sealing membrane.

According to one embodiment, the container is a second container, the sump structure comprises a first container, a lower part of which is located in the second container, the first fixing wing being an extension of the first container and the second fixing wing being an extension of the second container, and in which the at least one fixing means is located on the side wall of the second container.

According to one embodiment, the side wall has a cylindrical shape with an axis oriented in the direction of thickness. The cylindrical side wall can have different shapes in section.

According to one embodiment, the rigid container has a circular section, the transverse direction being a radial direction.

According to one embodiment of the invention, presented below in connection with the appended figures 1 to 5, the installation comprises at least one locking means configured to block the movement of the at least one fixing means in the thickness direction and in a tangent direction, the tangent direction being tangent to the side wall and orthogonal to the transverse direction and to the thickness direction.

According to one embodiment, the at least one fixing means comprises a fixing tab projecting from the rigid container in the transverse direction, the fixing tab having an orifice, and in which the installation comprises an anchoring device arranged in the hole to fix the fixing lug to the supporting structure in the thickness direction.

Thanks to these characteristics, the anchoring device makes it possible to prevent the displacement of the sump structure in the thickness direction relative to the support structure.

According to one embodiment, the blocking means comprises the anchoring device.

According to one embodiment, the installation comprises two stops fixed to the support structure and located on either side of the at least one fixing lug in a tangent direction, the tangent direction being tangent to the lateral and orthogonal wall in the transverse direction and in the thickness direction, the stops being configured to block the movement of the fixing lug in the tangent direction.

Thanks to these characteristics, the stops make it possible to prevent the displacement of the sump structure in the tangent direction relative to the support structure.

According to one embodiment, the blocking means is constituted by the combination of the stops and the anchoring device. According to one embodiment, the orifice comprises an oblong orifice, the largest dimension of which is oriented in the transverse direction so as to allow the transverse movement of the fixing lug and of the side wall relative to the anchoring device and to the supporting structure.

According to one embodiment, the orifice comprises a circular orifice having a diameter greater than a diameter of the anchoring device so as to allow the transverse movement of the fixing lug and the side wall relative to the anchoring device and to the supporting structure.

Thanks to these characteristics, the large dimension of the oblong hole or the diameter of the circular hole allows the fixing lug to move in the transverse direction relative to the anchoring device. Thus, the side wall of the sump structure can move relative to the support structure in the transverse direction, which has the effect of allowing thermal contraction of the sump structure.

According to one embodiment, the installation comprises two perforated plates comprising a perforation, the perforated plates being located on either side of the at least one fixing lug in the thickness direction and the anchoring device passing through the through the perforation of each perforated plate, the perforated plates being made of a material whose coefficient of friction is less than 0.2, preferably between 0.05 and 0.2.

Thanks to these characteristics, the perforated plates make it possible to tighten the fixing lug between the anchoring device and the support structure in the thickness direction while allowing the displacement of the fixing lug relative to the support structure in the direction cross. Indeed, the low coefficient of friction of the perforated plates makes it possible to minimize the friction force between the fixing lug and the supporting structure, which has the consequence of avoiding the degradation of the fixing lug and of facilitating the contraction of the sump structure.

According to one embodiment, the perforation of the perforated plate extends from an edge of the plate towards the center of the plate in the transverse direction so as to allow transverse positioning of the plate. According to one embodiment, the perforated plates are made of polytetrafluoroethylene (PTFE) or high density polyethylene (HDPE).

According to one embodiment, the stops and / or the shims are made of metal, for example stainless steel.

According to one embodiment, the waterproofing membrane, one of the waterproofing membranes or the waterproofing membranes are made of a metal among stainless steel, aluminum, Invar®: ie an alloy of iron and nickel whose coefficient of expansion is typically between 1, 2.10 ⁶ and 2.10 ⁶ K ¹ , or an alloy of iron with a high manganese content whose coefficient of expansion is of the order of 7.10 ⁶ K ¹ .

According to one embodiment, the fixing lug, the reinforcing bracket, the container or containers are made of metal, for example in the same metal as the waterproofing membrane to which they are fixed.

According to one embodiment, the anchoring device comprises a threaded rod or a stud and a nut, the threaded rod being fixed to the support structure and according to one embodiment, the threaded rod passes through the perforations of the perforated plates and the orifice of the fixing lug, the nut being configured to exert a clamping force in the thickness direction on the perforated plates and the fixing lug using the support structure.

According to one embodiment, the nut is welded in the clamping position on the threaded rod so as to ensure that the nut does not accidentally unscrew during use. The nut may be fixed by any other suitable locking means.

According to one embodiment, the installation comprises one or more shims disposed between the stops and the fixing lug in the tangent direction, the shims being configured to adjust the distance left free between a stop and a fixing lug in the tangent direction .

Thanks to these characteristics, the fixing of the sump structure is adjustable so as to take account of positioning tolerances.

According to one embodiment, the installation comprises at least one slide fixed to the support structure and directed in the transverse direction and the at least one fixing means is a fixing lug projecting from the rigid container in the transverse direction, the fixing lug being mounted in the slide, and the fixing lug being movable in the slide in the transverse direction to obtain said relative movement.

Thanks to these characteristics, the slide allows the side wall to move in the transverse direction so as to avoid subjecting the fastening to strong stresses during a thermal contraction.

According to one embodiment, the slide comprises a first portion projecting from the support structure in the thickness direction and a second portion connected to the first portion and directed in the tangent direction, so as to form a slide with shaped section. of the.

Thanks to these characteristics, the shape of the slide makes it possible to block the movement of the fixing lug and therefore of the sump structure in the thickness direction and at least partly in the tangent direction.

According to one embodiment, the blocking means comprises the slide.

According to one embodiment, the installation comprises two slides located on either side of the at least one fixing tab in the tangent direction, the slides being configured to block the movement of the fixing tab in the direction d 'thickness and in the tangent direction.

Thanks to these characteristics, the slides make it possible to block the movement of the fixing lug and therefore of the sump structure in the thickness direction and in the tangent direction.

According to one embodiment, the locking means consists of two slides located on either side of the fixing lug.

According to one embodiment, the sump structure comprises at least one reinforcing bracket, a first side of the reinforcing bracket being fixed on the fixing lug and a second side of the reinforcing bracket perpendicular to the first side being fixed to the rigid container. Thanks to these characteristics, the fixing lug is reinforced thanks to the reinforcement bracket, in particular in bending in the thickness direction, making it possible to prevent the fixing lug from being damaged during the use of the installation.

According to one embodiment, the fixing tab comprises two reinforcing brackets, the first side of the brackets being fixed on an upper surface or on a lower surface of the fixing tab, the brackets being placed on either side of the orifice of the mounting bracket.

According to one embodiment, the sump structure comprises a plurality of fixing means distributed regularly or irregularly around the circumference of the container, for example three or four fixing means.

Thanks to these characteristics, the sump structure is fixed around its entire circumference preventing it from moving as a whole while leaving the side wall free to contract or expand. This fixing can be carried out in a more or less uniform manner.

According to one embodiment, the at least one fixing means is an elastically deformable fastener comprising a first end welded to the support structure and a second end welded to the sump structure.

Thanks to these characteristics, the fastener can deform elastically and therefore allow the sump structure to contract while still fixing it to the supporting structure.

According to one embodiment, the fastener is formed continuously around the sump structure.

Thanks to these characteristics, the fastener is formed in a single piece fixing the sump structure to the support structure uniformly all around its circumference.

According to one embodiment, the fastener is perforated by days arranged all around the sump structure.

According to one embodiment, the installation comprises a plurality of elastically deformable fasteners distributed regularly or not all around the sump structure. Thanks to these characteristics, the fasteners make it possible to fix the sump structure to the supporting structure uniformly all around its circumference. Advantageously, the fasteners distributed non-periodically around the perimeter of the sump structure allow optimized fixing.

According to one embodiment, the section of the fastener in a normal vector plane directed in the tangent direction is straight or curved. Of course, the fasteners may have shapes of different section.

According to one embodiment, the section of the fastener is curved and comprises a curvature of constant sign, the curvature having a small or a large variation in curvature.

According to one embodiment, the section of the fastener is curved and comprises a plurality of curvatures with variation of the sign of curvature, so as for example to form at least one undulation.

According to one embodiment, the section of the fastener comprises a point of support on the support structure between the first end of the fastener and the second end of the fastener.

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

According to one embodiment, a vessel for the transport of a cold liquid product comprises an external hull and an aforementioned fluid storage installation arranged in the external hull, in which the carrying structure is an internal hull of the vessel.

According to one embodiment, the invention also provides a method of loading or unloading such a ship, in which a cold liquid product is conveyed through isolated pipes from or to a floating or land storage installation to or from the vessel of the ship. According to one embodiment, the invention also provides a transfer system for a cold liquid product, the system comprising the aforementioned ship, isolated pipes arranged so as to connect the tank installed in the hull of the ship to a floating storage installation. or terrestrial and a pump to drive a flow of cold liquid product through the insulated pipes from or to the floating or terrestrial storage facility to or from the vessel

Brief description of the figures

The invention will be better understood, and other objects, 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 without limitation. , with reference to the accompanying drawings.

- Figure 1 shows a perspective view of a sump structure attached to a support structure according to a first embodiment.

- Figure 2 is a detail view of Figure 1.

- Figure 3 shows a partial perspective view of a sump structure attached to a support structure according to a second embodiment.

- Figure 4 is a sectional view of Figure 3 along the section plane

IV-IV.

- Figure 5 is a sectional view of Figure 4 along the section plane

VV.

- Figure 6 shows a schematic sectional view of a sump structure attached to a support structure according to a third embodiment.

- Figure 7 in Figure 14 show different embodiments of fixing means arranged to fix the sump structure to the support structure.

- Figure 15 is a cutaway schematic representation of an LNG vessel comprising a storage installation and a loading / unloading terminal of this storage installation.

Detailed description of embodiments In the description below, there will be described a storage installation 71 comprising a support structure 1, a sealed and thermally insulating tank and a sump structure 9 which can be used in the bottom wall 4 of a storage tank and / or LNG transport. The bottom wall 4 designates a wall 4, preferably generally planar, located at the bottom of the tank relative to the earth's gravity field. The general geometry of the tank can also be of different types. Polyhedral geometries are the most common. Cylindrical, spherical or other geometry is also possible.

The walls 4 of the tank are formed by a multilayer structure fixed on load-bearing walls 1 and including two waterproof membranes 5, 7 alternated with two thermally insulating barriers 6, 8. Since there are many known techniques for producing these structures multilayer, the description below will be limited to the sump structure 9 and the fixing thereof to the support structure 1 of the storage installation 71.

The vessel wall 4 is mounted on a support structure 1, made for example from thick sheet steel such as the inner hull of a double hull ship 70. The tank wall 4 has a multilayer structure successively including a secondary thermal insulation barrier 8 fixed to the supporting structure 1, for example by means of mastic beads, a secondary sealing membrane 7 supported by the thermal insulation barrier secondary 8, a primary thermal insulation barrier 6 covering the secondary sealing membrane 7 and a primary sealing membrane 5 supported by the primary thermal insulation barrier 6.

FIG. 1 represents a sump structure 9 fixed to a support structure 1 according to a first embodiment.

At the location of the sump structure 9, the supporting structure has an opening 2, illustrated in FIG. 1, of circular shape, through which the sump structure 9 is engaged and which allows the sump structure 9 to protrude at the outside of the supporting structure 1 in the thickness direction of the tank wall 4. A rigid cylindrical container 10, 1 1 is fixed on the support structure 1 by means of one or more fixing means 15, 32 around the opening 2 and protrudes towards the outside of the support structure 1 to form an extension structure which provides additional space for housing the sump structure 9. More specifically, the container 10, 11 has a cylindrical side wall 12, for example circular or other. The container 10, 11 can be made of materials similar to the support structure 1 or to one of the sealing membranes 5, 7.

The sump structure 9 comprises a first container 10 in communication with the interior of the tank, and a second container 11 surrounding the lower part of the first container 10. The first container 10 is continuously connected to the sealing membrane primary 5, which it thus completes in a sealed manner. Likewise, the second container 11 is connected continuously to the secondary sealing membrane 7, which it thus completes in a leaktight manner.

More specifically, the first container 1 1 has a cylindrical side wall 12 whose axis is perpendicular to the support structure 1 and which has a first fixing wing located on an upper part of the side wall and essentially aligned with the membrane primary seal 5 and a lower part engaged in the opening 2 below the support structure. A bottom wall parallel to the support structure 1 closes the cylindrical side wall at its lower part. The first fixing wing is fixed at the edge of the upper part of the cylindrical side wall and projects radially outside of it all around the first container 10.

The primary sealing membrane 5 thus has an interruption in the form of a window, for example a circular or square window, the edge of which surrounds the sump structure 9 and is sealingly connected to the first fixing wing 13 , for example by welding or gluing, as visible in Figure 6.

Similarly, the second container 11 has a cylindrical side wall 12 whose axis is perpendicular to the supporting structure 1 and which has a second fixing wing 14 essentially aligned with the membrane secondary seal 7 and a lower part engaged in the opening below the bottom wall of the first container 10. A bottom wall parallel to the support structure closes the cylindrical side wall 12 of the second container 1 1 at its lower part. The cylindrical side wall 12 of the second container 1 1 surrounds the cylindrical side wall of the first container 10 at a distance therefrom. The second fixing wing 14 is fixed at the edge of the upper part of the cylindrical side wall 12 and projects radially outside of the latter all around the second container 11.

The secondary waterproofing membrane 7 also has an interruption in the form of a window, for example a circular or square window, the edge of which surrounds the sump structure 9 and is sealingly connected to the second fixing wing 14 , for example by welding or gluing, as visible in Figure 6.

In the tank wall 4, the space between the support structure 1 and the secondary sealing membrane 7 is a secondary space containing the secondary thermally insulating barrier 8 and in which it is possible to circulate a flow of nitrogen by security measure. In the sump structure 9, the space between the second container 1 1 and the support structure 1 is also a secondary space which communicates with the secondary space of the tank wall 4 in order to be able to receive this nitrogen sweep.

The secondary thermally insulating barrier 8 is for example formed from juxtaposed modular blocks for lining the support structure 1 relatively uniformly. These modular blocks stop at a certain distance from the sump structure 9, as visible in FIG. 6. Insulating blocks of suitable shape can be designed to approach relatively close to the sump structure 9 or to fit into it. and thus limit the gap remaining to be filled in the secondary insulation. Insulating materials are housed in the gap between the edge of the secondary thermally insulating barrier 8 and the second container, as well as in the secondary space of the sump structure 9 to complete the thermal insulation around the second container 11. Indeed, the secondary sealing membrane 7 and the second container 1 1 are likely to be in contact with the cryogenic fluid in the event of an accidental leak in the primary sealing membrane 5.

Similarly, in the tank wall 4, the space between the secondary sealing membrane 7 and the primary sealing membrane 5 is a primary space containing the primary thermally insulating barrier 6 and in which it is possible to circulate a nitrogen flow for safety. In the sump structure 9, the space between the first container 10 and the second container 11 is also a primary space which communicates with the primary space of the tank wall 4 in order to be able to receive this nitrogen sweep.

The primary thermally insulating barrier 6 is for example formed of juxtaposed modular blocks for lining the secondary sealing membrane 7 relatively uniformly. These modular blocks stop at a certain distance from the sump structure 9. Shaped insulating blocks adapted can be designed to approach relatively close to the sump structure 9 or fit into it and thus limit the gap remaining to be filled in the primary insulation. Insulating materials are housed in the gap between the edge of the primary insulating barrier 6 and the first container 10, as well as in the primary space of the sump structure 9 to complete the thermal insulation around the first container 10. In Indeed, the primary membrane 5 and the first container 10 are in contact with the LNG during use.

Different insulating materials may be suitable to complete the primary and secondary thermal insulation, for example glass or rock wool, polymer foams, in particular polyurethane or PVC, balsa wood, plywood, aerogels, and others.

In service, due to its position below the primary sealing membrane 5, the first container 10 receives by gravity any liquid residue present in the tank, in the manner of a sump. The first container 10 has sufficient capacity to keep the suction head of the pump immersed in the liquid and thus maximizes the operating efficiency of the tank. To have good structural stability, the first container 10 and the second container 11 are made of a more rigid material than the waterproof membranes, for example with a metal sheet of the order of 6 to 20 mm thick.

Other embodiments of a sump structure 9 are for example described in the document WO2016 / 001,142.

In the first embodiment illustrated in Figures 1 and 2, the sump structure comprises on the cylindrical side wall 12 of the second container 1 1 fixing means 15 in the form of fixing lugs 15. The fixing lugs 15 allow the fixing from the sump structure 9 to the supporting structure 1.

The fixing lugs 15 protrude from the second container 1 1 in the radial direction and are distributed regularly all around the side wall 12, for example as illustrated in FIG. 1 the fixing lugs 15 are three in number and are located at 120 ° from each other.

In order to stiffen each fixing lug 15, the sump structure 9 comprises two reinforcing brackets 16 on each fixing lug 15. The reinforcing brackets 16 have a first side 20 fixed on an upper surface of a fixing lug 15 and a second side 21 perpendicular to the first side 20 fixed to the side wall 12 of the second container 11.

The support structure 1 comprises near the opening 2 of the slides 17. The slides 17 are formed by a first portion 18 projecting from the support structure 1 in the thickness direction and by a second portion 19 connected to the first portion 18 directed in the tangent direction so as to form L-shaped section slides. As illustrated in FIGS. 1 and 2, each fixing lug 15 is sandwiched between two slides 17 so that a part of the second portion 19 of each slide 17 is placed above the fixing lug in the thickness direction. Thus placed, the slides 17 make it possible to block the movement of the fixing lugs 15 and therefore of the sump structure in the thickness direction and in the tangent direction.

In addition, the slides 17 allow each fixing lug 15 to retain a degree of freedom, namely the translation in the radial direction of so as to allow the contraction or thermal expansion of the sump structure 9.

Figures 3 to 5 show a second embodiment of the attachment of a sump structure 9 to a support structure 1. This embodiment differs from the first embodiment by the locking system of the fixing lugs 15. Indeed , as shown in FIGS. 3 to 5, the fixing lugs 15 of the second embodiment are similar to those of the first embodiment, they nevertheless include in the second embodiment an orifice 22 with an orifice diameter 23 . However, no slide 17 is used to block certain degrees of freedom of the fixing lugs 15 on the support structure 1. In place of the slides 17, stops 28 are fixed on the support structure 1 near the opening 2. The stops 28 are placed on the supporting structure 1 so as to frame each fixing lug 15 of the sump structure 9 in the tangent direction.

An anchoring device 24 composed of a threaded rod 25 with a diameter

27 of threaded rod and a nut 26 is inserted into the orifice 22 of each fixing lug 15 in the thickness direction. The anchoring device 24 is fixed in the support structure 1 by one of its ends, the nut 26 being placed at the other of its ends so as to sandwich the fixing lug 15 with the support structure in the direction thick. The anchoring device 24 thus blocks in the thickness direction the fixing lug 15 by clamping against the support structure 1. The nut 26 is welded to the threaded rod 25 in the tightening position so as to prevent the nut from loosening when using the storage installation 71.

As can be seen in FIGS. 4 and 5, the orifice 22 is a circular orifice whose diameter 23 is greater than the diameter 27 of the threaded rod 25 so as to leave the fixing lug 15 in particular in the radial direction a some travel so that the sump structure 9 can contract or expand. In another embodiment not shown, the orifice 22 is an oblong orifice whose large dimension is located in the radial direction.

So that the tightening of the fixing lug 15 by the anchoring device 24 does not harm the potential displacement of the sump structure 9 under the effect of thermal contraction, perforated plates 29 comprising a perforation 30 and made of a material having a low coefficient of friction such as PTFE are arranged on either side of the fixing lug 15 so as to be interposed between the nut 26 and the support structure 1, as visible in the figure 5 in particular. The threaded rod 25 of the anchoring device 24 also passes through the perforations 30 of the perforated plates 29.

Thanks to the low coefficient of friction of the perforated plates 29, the friction force between the perforated plates and the fixing lug 15 is minimized allowing the fixing lug 15 and therefore the sump structure to contract or expand in the radial direction.

In order to adjust the distance between the stops 28 and the fixing lug 15 in the tangent direction, shims 31 are interposed between each stop 28 and the fixing lug 15 so as to ensure that the movement of the fixing lug 15 in the tangent direction is not too important.

Figures 6 to 14 show a plurality of variants for fixing the sump structure 9 to the support structure according to a third embodiment. In this embodiment, unlike the previous embodiments, there is no longer any question of leaving the fixing means free in the radial direction but rather of using an elastically deformable fixing means, making it possible, using its deformation, to compensate for the thermal contraction of the sump structure 9.

As illustrated in FIG. 6, the sump structure 9 is fixed to the support structure 1 by means of at least one clip 32 which is elastically deformable. The fastener 32 comprises a first end welded to the support structure 1 while a second end opposite the first end is welded to the sump structure 9, for example on the side wall 12 of the second container 1 1 or on the second fixing wing 14.

In a normal vector plane in the tangent direction, the section of the fastener 32 is defined by its height 33, namely its dimension in the thickness direction, its wheelbase 34, namely its dimension in the radial direction and its thickness 35 , as shown in figure 7. The section of the fastener 32 may, according to a plurality of variants, be of different shapes thus influencing its stiffness in the radial direction so as to deform more or less easily under the effect of the contraction or expansion of the structure of sump 9. In fact, in the mode illustrated in FIG. 6, the section of the fastener is rectilinear.

FIG. 7 represents a curved fastening section whose curvature is of constant sign, the curvature varying slightly.

FIG. 8 represents a curved attachment section whose curvature is of constant sign, the curvature varying greatly.

FIG. 9 represents a curved attachment section whose curvature includes a change of sign, therefore a point of inflection, so that the attachment section is slightly wavy.

FIG. 10 represents a curved attachment section whose curvature comprises a plurality of changes of signs so as to form a ripple 37.

Figure 1 1 shows a curved attachment section whose curvature comprises a plurality of change of signs, the curvature varying abruptly at a plurality of points. In addition, the fastener 32 in this variant comprises a point of support 38 on the support structure 1 between the first end and the second end of the fastener 32 so as to reinforce its stiffness in the thickness direction.

FIG. 12 represents a variant of the third embodiment in which the storage installation 71 comprises a plurality of fasteners 32 distributed regularly or not over the circumference of the second container 1 1. In this variant, the sump structure 9 is therefore fixed to the support structure 1 in a discrete manner by a plurality of fasteners 32.

Unlike Figure 12, Figure 13 shows a variant in which the storage installation 71 comprises a single clip 32, one edge of which matches the shape of the side wall 12 of the second container 11 and is welded around the entire circumference of that -this, while an opposite edge is welded to the structure carrier 1. In this variant, the sump structure 9 is therefore fixed to the carrier structure 1 continuously by a single clip 32.

FIG. 14 shows another variant of the third embodiment. In this variant, the fastener 32 is of the same shape as that illustrated in FIG. 12. However, the fastener 32 in FIG. 14 includes days 36 distributed periodically over the entire surface of the fastener 32. The days 36 allow in particular to vary the stiffness of the fastener 32 so that it can deform elastically under the effect of the contraction or expansion of the sump structure 9. In the embodiment presented, the days 36 are oblong and are located between the two edges of the fastener 32. In other variants not shown, the days 36 are located on one or each of the edges of the fastener 32 so as to interrupt the fixing of the 'attaches 32 periodically or not. In addition, the days can be of variable shapes, for example polygonal or circular.

The technique described above for making a storage installation can be used in different types of tanks, for example an LNG tank in a land installation or in a floating structure such as an LNG tanker or other.

With reference to FIG. 15, a cutaway view of an LNG tanker 70 shows a sealed and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the ship. The wall of the tank 71 comprises a primary waterproof barrier intended to be in contact with the LNG contained in the tank, a secondary waterproof barrier arranged between the primary waterproof barrier and the double hull 72 of the ship, and two insulating barriers arranged respectively between the primary waterproof barrier and the secondary waterproof barrier and between the secondary waterproof barrier and the double shell 72.

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

FIG. 15 represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipe 76 and a installation on land 77. The loading and unloading station 75 is a fixed offshore installation comprising a mobile arm 74 and a tower 78 which supports the mobile arm 74. The mobile arm 74 carries a bundle of insulated flexible pipes 79 which can be connect to the loading / unloading lines 73. The movable arm 74 can be adjusted to suit all sizes of LNG carriers. A connection 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. This comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the subsea pipe 76 to the loading or unloading station 75. The subsea pipe 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the shore installation 77 over a long distance, for example 5 km, which makes it possible to keep the LNG carrier 70 at a great distance from the coast during the 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 "behave", "understand" or "include" and its conjugate forms do not exclude the presence of other elements or 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

1. Fluid storage installation (71), the storage installation (71) comprising a support structure (1) and a sealed and thermally insulating tank, the tank comprising at least one bottom wall (4) fixed to the support structure ( 1), in which the bottom wall (4) comprises a multilayer structure superimposed in a thickness direction including at least one sealing membrane (5, 7) and at least one thermal insulation barrier (6, 8) disposed between the waterproofing membrane (5, 7) and the supporting structure (1), in which the bottom wall (4) comprises a sump structure (9) locally interrupting the waterproofing membrane (5, 7 ) from the bottom wall (4), the sump structure (9) comprising a rigid container (10, 1 1) comprising a side wall (12), the container (10, 1 1) being arranged through the thickness of the bottom wall (4), and the sump structure (9) comprising at least one fixing means tion (15, 32) arranged to fix the rigid container (10, 1 1) to the support structure (1) at a point of attachment of the side wall (12),

and wherein the at least one fixing means (15, 32) is configured to allow relative movement of the side wall (12) of the container (10, 1 1) relative to the support structure (1) in a direction transverse perpendicular to the side wall (12) at the point of attachment of the container (10, 1 1), the relative displacement being greater than 1 mm.

2. Installation according to claim 1, wherein the side wall (12) has a cylindrical shape with an axis oriented in the direction of thickness.

3. Installation according to claim 1 or 2, wherein the rigid container (10, 1 1) has a circular section, the transverse direction being a radial direction.

4. Installation according to one of the preceding claims, in which the installation comprises at least one locking means (17, 26/28) configured to block the movement of the at least one fixing means in the thickness direction. and in a tangent direction, the tangent direction being tangent to the side wall (12) and orthogonal to the transverse direction and to the thickness direction.

5. Installation according to one of claims 1 to 4, wherein the at least one fixing means (15) comprises a fixing lug (15) projecting from the rigid container in the transverse direction, the fixing lug (15 ) comprising an opening (22), and in which the installation comprises an anchoring device (24) arranged in the opening (22) for fixing the fixing lug (15) to the support structure (1) in the direction thick.

6. Installation according to claim 5, wherein the installation comprises two stops (28) fixed to the support structure (1) and located on either side of the at least one fixing lug (15) in one direction tangent, the tangent direction being tangent to the side wall (12) and orthogonal to the transverse direction and to the thickness direction, the stops (28) being configured to block the movement of the fixing lug (15) in the direction tangent.

7. Installation according to claim 5 or claim 6, wherein the orifice (22) comprises an orifice (22) oblong whose largest dimension is oriented in the transverse direction so as to allow the transverse movement of the fixing lug (15) and the side wall (12) relative to the anchoring device (24) and to the support structure (1).

8. Installation according to one of claims 5 to 7, wherein the installation comprises two perforated plates (29) having a perforation (30), the perforated plates (29) being located on either side of the at least a fixing lug (15) in the thickness direction and the anchoring device (24) passing through the perforation (30) of each perforated plate (29), and in which the perforated plates (29) are produced in a material whose coefficient of friction is less than 0.2.

9. Storage installation according to claim 8, in which the anchoring device (24) comprises a threaded rod (25) and a nut (26), the threaded rod (25) being fixed to the support structure (1) and passing through the perforations (30) of the perforated plates (29) and the orifice (22) of the fixing lug (15), the nut (26) being configured to exert a clamping force in the thickness direction on the perforated plates (29) and the fixing lug (15) using the support structure (1).

10. Installation according to claim 6 or one of claims 7 to 9 taken in dependence on claim 6, wherein the installation comprises shims (31) disposed between the stops (28) and the fixing lug (15 ) in the tangent direction, the shims (31) being configured to adjust the distance left free between a stop (28) and a fixing lug (15) in the tangent direction.

1 1. Installation according to one of claims 1 to 4, in which the installation comprises at least one slide (17) fixed to the support structure (1) and directed in the transverse direction and the at least one fixing means is a lug fixing (15) projecting from the rigid container (10, 1 1) in the transverse direction, the fixing lug (15) being mounted in the slide (17), and the fixing lug (15) being movable in the slide (17) in the transverse direction to obtain said relative displacement.

12. Installation according to claim 1 1, wherein the slide (17) has a first portion (18) projecting from the support structure (1) in the thickness direction and a second portion (19) connected to the first portion (18) and directed in a tangent direction orthogonal to the transverse direction, so as to form a slide in L-shaped section.

13. Installation according to claim 1 1 or claim 12, wherein the installation comprises two slides (17) located on either side of the at least one fixing lug (15) in a tangent direction orthogonal to the transverse direction, the slides (17) being configured to block the movement of the fixing lug (15) in the thickness direction and in the tangent direction

14. Installation according to one of claims 1 to 13, in which the sump structure (9) comprises at least one reinforcement bracket (16), a first side of the reinforcement bracket (16) being fixed on the lug fixing (15) and a second side of the reinforcement bracket (15) perpendicular to the first side being fixed to the rigid container (10, 1 1).

15. Installation according to one of claims 1 to 14, wherein the sump structure (9) comprises a plurality of fixing means (15, 32) distributed regularly over the circumference of the container (10, 1 1).

16. Installation according to one of claims 1 to 3, in which the at least one fixing means is an elastically deformable fastener (32) comprising a first end welded to the support structure (1) and a second end welded to the sump structure (9).

17. Installation according to claim 16, in which the fastener (32) is formed continuously around the sump structure (9).

18. Installation according to claim 16 or claim 17, wherein the fastener (32) is perforated by days (36) arranged periodically all around the sump structure (9).

19. Installation according to claim 16, wherein the installation comprises a plurality of elastically deformable fasteners (32) regularly distributed all around the sump structure (9).

20. Installation according to one of claims 16 to 19, wherein the section of the fastener (32) in a normal vector plane directed in a tangent direction orthogonal to the transverse direction, is straight or curved.

21. Vessel (70) for transporting a cold liquid product, the vessel comprising an external hull (72) and a fluid storage installation according to one of claims 1 to 20 disposed in the external hull (72), in which the supporting structure (1) is an internal hull of the ship (70).

22. A method of loading or unloading a ship (70) according to claim 21, in which a cold liquid product is conveyed through insulated pipes (73, 79, 76, 81) from or to a floating storage installation or terrestrial (77) to or from the vessel (71).

23. Transfer system for a cold liquid product, the system comprising a vessel (70) according to claim 21, insulated pipes (73, 79, 76, 81) arranged so as to connect the tank (71) installed in the hull from the ship to a floating or terrestrial storage facility (77) and a pump for driving a flow of cold liquid product through the isolated pipes from or to the floating or terrestrial storage facility to or from the vessel of the ship.