WO2019239049A1

WO2019239049A1 - Sealed and thermally insulating tank

Info

Publication number: WO2019239049A1
Application number: PCT/FR2019/051396
Authority: WO
Inventors: Antoine PHILIPPE; Sébastien DELANOE; Raphaël PRUNIER
Original assignee: Gaztransport Et Technigaz
Priority date: 2018-06-13
Filing date: 2019-06-10
Publication date: 2019-12-19
Also published as: FR3082595B1; KR102475415B1; JP2021527188A; SG11202011733RA; CN112352125B; EP3807567A1; KR20210021307A; FR3082595A1; JP7354158B2; CN112352125A

Abstract

The invention relates to a sealed and thermally insulating tank for storing a fluid, comprising a tank wall having a thermally insulating barrier and a sealing membrane, in which the thermally insulating barrier comprises juxtaposed insulating panels (24) of a parallelepiped shape and having a bottom panel (25) and an insulating lining (26, 28), the bottom panel (25) defining a bearing surface (31), wherein a wedge (32) is arranged on said bearing surface (31), in which at least one of the anchoring devices (45) comprises a support member (33) configured to exert pressure on the wedge (32) in the direction of the bearing surface (31), and in which either the wedge (32) or the bottom panel (25) has in the thickness direction of the tank wall a coefficient of thermal contraction greater than the coefficient of thermal contraction of said anchoring device (45) and the other of the wedge (32) or the bottom panel (25) has a coefficient of thermal contraction lower than the coefficient of thermal contraction of the anchoring device (45).

Description

WATERPROOF AND THERMALLY INSULATING TANK

Technical area

The invention relates to the field of tanks, sealed and thermally insulating, with membranes, for the storage and / or transport of fluid, such as a liquefied gas.

Sealed and thermally insulating tanks with membranes are used in particular for the storage of liquefied natural gas (LNG), which is stored, at atmospheric pressure, at around -163 ° C. These tanks can be installed on the ground or on a floating structure. In the case of a floating structure, the tank may be intended for the transport of liquefied natural gas or to receive liquefied natural gas serving as fuel for the propulsion of the floating structure.

Technological background

Application WO2014 / 170588 discloses a sealed and thermally insulating tank for the storage of liquefied natural gas, which is integrated in the double hull of a ship. Each tank wall has a multilayer structure and successively has, in the thickness direction, from the outside towards the inside of the tank, a secondary thermally insulating barrier retained at a support structure, a secondary sealing membrane resting against the secondary thermally insulating barrier, a primary thermally insulating barrier resting against the secondary sealing membrane and a primary sealing membrane intended to be in contact with the liquefied natural gas contained in the tank and resting against the primary thermally insulating barrier.

In the aforementioned document, the thermally insulating barrier comprises a plurality of primary insulating panels which are anchored on secondary insulating panels of the secondary thermally insulating barrier, by means of anchoring devices. All anchoring devices are equipped with a stack of elastic washers which ensures elastic anchoring of the primary insulating panels on the secondary insulating panels. Such an elastic anchoring makes it possible to hold the primary insulating panels against the secondary insulating panels while allowing slight relative displacements of the primary insulating panels with respect to the secondary insulating panels. This makes it possible to limit the constraints likely to be exerted on the primary insulating panels and on the secondary insulating panels in the anchoring zones. However, such a sealed tank is not entirely satisfactory. In particular, such anchoring devices require a large number of stacking Belleville washers, which increases the cost of the tank equipped with such anchoring devices as well as the complexity of its manufacture.

summary

One idea underlying the invention consists in proposing a sealed and thermally insulating tank in which the anchoring of the insulating panels is carried out in a simpler and more economical manner.

According to one embodiment, the invention provides a sealed and thermally insulating tank for storing a fluid comprising a tank wall having successively in a thickness direction of the tank wall, from the outside to the inside of the tank, a thermally insulating barrier intended to be anchored to a support structure and a waterproofing membrane which rests against the thermally insulating barrier,

in which the thermally insulating barrier comprises insulating panels of parallelepipedal shape juxtaposed and intended to be anchored on the support structure, said insulating panels having a bottom plate and an insulating lining, the bottom plate defining a support surface projecting laterally of the insulating lining, said bearing surface being turned towards the inside of the tank, a shim being arranged on said bearing surface, said shim having an internal surface turned towards the inside of the tank,

in which anchoring devices intended to be fixed on the support structure between the insulating panels cooperate with said insulating panels, said anchoring devices being intended to retain the insulating panels against the support structure;

in which at least one of the anchoring devices comprises a support member having an external face turned towards the shim, said support member being configured so that said external face exerts a support on the internal face of the shim in the direction of the support surface, and in which one of the wedge and the bottom plate has a coefficient of thermal contraction in the direction of thickness of the vessel wall greater than the coefficient of thermal contraction of said anchoring device in said direction of thickness and l Another among the wedge and the bottom plate has a coefficient of thermal contraction in said thickness direction less than the coefficient of thermal contraction of the anchoring device in said thickness direction.

Thanks to these characteristics, the assembly formed by the bottom panel and the shim exhibits a behavior in thermal contraction close to that of the anchoring device. More particularly, the behavior in thermal contraction of this assembly allows the maintenance of the cooperation between the wedge and the support member despite the temperature variations. In other words, this assembly is prevented from contracting more than the anchoring member in order to maintain the support of said anchoring device on the wedge. Thus, the cooperation between the support member and the wedge is maintained so as to keep the anchoring of the insulating panels on the supporting structure in a simple and reliable manner. In particular, the anchoring device does not require the use of numerous elastic washers in order to maintain the anchoring of the insulating panels despite the deformations linked to the thermal contraction in the tank or to the deformations of the supporting structure.

The term thermal coefficient of contraction of the anchoring device is understood to mean the behavior in thermal contraction of all the constituent elements of said anchoring device at the level of the bottom plate and of the shim. In other words, this coefficient of thermal contraction defines the behavior in thermal contraction of the assembly formed by the element or elements constituting the anchoring device on a portion of said anchoring device located substantially in the same thickness section of the wall. tank as the bottom plate and shim. This coefficient of thermal contraction of the anchoring device can be measured experimentally or calculated from knowledge of the different materials making up all of the elements forming said anchoring device.

According to other advantageous embodiments, such a tank may have one or more of the following characteristics. According to one embodiment, the coefficient of thermal contraction of the wedge is less than the coefficient of thermal contraction of the bottom plate.

According to one embodiment, the shim and the bottom plate have a respective dimension in the thickness direction configured so that the support member exerts, preferably continuously, the support on the internal face of the shim in the direction of the support surface when the temperature decreases from room temperature.

According to one embodiment, the dimensional variation of the anchoring device in the thickness direction of the tank wall is higher than the dimensional variation in said thickness direction of the assembly formed of the bottom plate and the shim during a temperature change from 20 ° C to -163 ° C.

In other words, the external face of the support member moves in the thickness direction of the vessel wall more than the displacement of the internal face of the shim during a temperature change in the vessel. Thus, the support of the support member on the hold is maintained despite the temperature change in the tank.

According to one embodiment, at room temperature, the support member exerts a support on the wedge in the direction of the support area

According to one embodiment, the difference in difference in dimensional variation in the thickness direction of the tank wall during a temperature change from 20 ° C to -163 ° C between the anchoring member and the he assembly formed of the bottom plate and the shim is between 5.50E-05 mm and 9.69E-02 mm. By convention, "EN" means 10 ^N in this description.

In other words, the displacement of the external face of the support member is greater by a value of 5.50E-05 mm to 9.69E-02 mm compared to the displacement of the internal face of the wedge during a change temperature in the tank going from 20 ° C to -163 ° C.

According to one embodiment, the wedge is made of plywood. According to one embodiment, such a plywood wedge is arranged so as to present fibers oriented in a plane parallel to the thickness direction of the tank wall.

According to one embodiment, the bottom plate is made of plywood. According to one embodiment, the plywood bottom plate is arranged so as to have fibers oriented in a plane perpendicular to the thickness direction of the tank wall.

According to one embodiment, the shim has a coefficient of thermal contraction in the thickness direction of the tank wall of between 4E-06 K ¹ and 8E-06 K ¹ , for example 5.50E-06 K ¹ .

According to one embodiment, the bottom plate has a coefficient of thermal contraction in the thickness direction of the tank wall of between 3E-05 K ¹ and 4E-05 K ¹ , for example 3.65E-05 K ¹ .

According to one embodiment, the anchoring device has a coefficient of thermal contraction in the thickness direction of the tank wall of between 1.4E-05 K ¹ and 1.8E-05 K ¹ , for example 1.6E-05 K ¹ .

According to one embodiment, in a thickness direction of the tank wall, the bottom plate has a thickness of 9mm and the shim has a thickness between 17.6mm and 68mm.

According to one embodiment, the shim has a constant section along the thickness direction of the tank. According to one embodiment, the shim rests on at least 50% of the support surface of the insulating panel.

According to one embodiment, the wedge is arranged on the bearing surface of two adjacent insulating panels so that the bearing member exerts a bearing on said wedge in the direction of the bearing surfaces of said two adjacent insulating panels.

According to one embodiment, the thermally insulating barrier is a primary thermally insulating barrier, the insulating panels are primary insulating panels, the waterproofing membrane is a primary waterproofing membrane and the support member is a primary support, the vessel wall further comprising a secondary thermally insulating barrier and a secondary waterproofing membrane intended to be interposed between the primary thermally insulating barrier and the support structure.

According to another embodiment, at least one of the insulating panels comprises a cover plate and carrier webs extending, in the thickness direction of the tank wall, between the bottom plate and the cover plate and delimiting a plurality of compartments filled with an insulating lining, such as perlite.

According to one embodiment, at least one of the insulating panels comprises a cover plate, the insulating lining being interposed between the bottom plate and the cover plate, said insulating panel further comprising an intermediate plate disposed between the bottom plate and the cover plate, the insulating lining comprising a first layer of insulating polymeric foam sandwiched between the bottom plate and the intermediate plate and a second layer of insulating polymeric foam sandwiched between the intermediate plate and the cover plate.

According to one embodiment, recesses are provided in the layers of insulating polymeric foam and in the intermediate plate and the cover plate so that the bottom plate projects beyond said layers of insulating polymeric foam and at the intermediate plates and bottom thus sparing the bearing surface on the bottom plate.

According to one embodiment, the secondary thermally insulating barrier comprises a plurality of secondary insulating panels juxtaposed on the supporting structure, the tank further comprising a plurality of anchoring members intended to anchor the secondary insulating panels on the supporting structure.

According to one embodiment, the primary insulating panels rest on the secondary sealing membrane, the anchoring device developing from the secondary sealing membrane. According to one embodiment, the anchoring device is fixed to an anchoring member at the level of the secondary waterproof membrane. In other words, the anchoring device and the bottom plate both develop, in the thickness direction of the tank wall, from the secondary sealing membrane. According to one embodiment, the first layer of insulating polymeric foam has, in each of the corner areas of the insulating panel, a cutout accommodating a pillar which extends between the bottom plate and the intermediate plate. This limits the crushing and creep of the foam.

According to one embodiment, the fluid is a liquefied gas, such as liquefied natural gas.

Such a tank can be part of a terrestrial storage installation, for example to store LNG or be installed in a floating structure, coastal or deep water, in particular an LNG tanker, a floating storage and regasification unit (FSRU) , a floating production and remote storage unit (FPSO) and others.

According to one embodiment, the invention also provides a vessel for the transport of a cryogenic fluid comprises a double hull and a said tank disposed in the double hull.

According to one embodiment, the double shell has an internal shell forming the carrying structure of the tank.

According to one embodiment, the invention also provides a method of loading or unloading such a ship, in which a fluid is conveyed through insulated pipes from or to a floating or terrestrial storage installation towards or from the tank of the ship.

According to one embodiment, the invention also provides a transfer system for a fluid, 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 or land storage installation. and a pump for driving a fluid through the insulated pipes from or to the floating or land storage facility to or from the vessel of the ship.

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 is a cutaway perspective view of a vessel wall;

Figure 2 is a perspective view of a secondary insulating panel;

Figure 3 is a partial perspective view of a primary insulating panel;

Figure 4 is a perspective view of an anchoring device for primary insulating panels and secondary insulating panels;

Figure 5 is a partial exploded view of the anchoring device of Figure 4 integrated in the tank wall of Figure 1;

Figure 6 is a schematic perspective view of detail of Figure 5 illustrating a first embodiment of the anchor wedge of the primary panel;

Figure 7 is a top view of Figure 5;

Figures 8 and 9 are detail views respectively in schematic perspective and from above of a second embodiment of the anchor wedge;

Figures 10 and 11 are detail views respectively in schematic perspective and from above of a third embodiment of the anchor wedge;

FIG. 12 is a cutaway schematic representation of an LNG tank and a loading / unloading terminal for this tank.

Figure 13 is a cutaway perspective view of a tank wall according to another embodiment; Figure 14 is an enlarged view of the area XIII of Figure 13, further showing a primary anchor according to one embodiment.

Detailed description of embodiments

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

In Figure 1, there is shown the multilayer structure of a wall 1 of a sealed and thermally insulating tank for storing a liquefied fluid, such as liquefied natural gas (LNG). Each wall 1 of the tank successively comprises, in the thickness direction, from the outside towards the inside of the tank, a secondary thermally insulating barrier 2 retained at a support structure 3, a secondary sealing membrane 4 resting against the secondary thermally insulating barrier 2, a primary thermally insulating barrier 5 resting against the secondary sealing membrane 4 and a primary sealing membrane 6 intended to be in contact with the liquefied natural gas contained in the tank.

The supporting structure 3 can in particular be formed by the hull or double hull of a ship. The supporting structure 3 comprises a plurality of walls defining the general shape of the tank, usually a polyhedral shape.

The secondary thermally insulating barrier 2 comprises a plurality of secondary insulating panels 7 which are anchored to the support structure 3 by means of anchoring devices 8 which will be described in detail below. The secondary insulating panels 7 have a generally parallelepiped shape and are arranged in parallel rows.

In relation to FIG. 2, the structure of a secondary insulating panel 7 is observed according to an embodiment. The secondary insulating panel 7 here comprises three plates, namely a bottom plate 9, an intermediate plate 10 and a cover plate 1 1. The bottom plates 9, intermediate 10 and cover 1 1 are for example made of plywood . The secondary insulating panel 7 also comprises a first layer of insulating polymer foam 12 sandwiched between the bottom plate 9 and the intermediate plate 10 and a second layer of insulating polymer foam 13 sandwiched between the intermediate plate 10 and the cover plate 11. The first and second layers of insulating polymer foam 12, 13 are respectively bonded to the bottom plates 9 and intermediate 10 and to the intermediate plates 10 and cover 11. The insulating polymer foam can in particular be a polyurethane-based foam, optionally reinforced with fibers.

The first layer of insulating polymer foam 12 has, in the corner areas, cut-outs to allow corner pillars 14 to pass. The corner pillars 14 extend, at the four corner areas of the secondary insulating panel 7, between the bottom plate 9 and the intermediate plate 10. The corner pillars 14 are fixed, for example by means of staples or screws or glued, on the bottom plate 9 and the intermediate plate 10 and optionally on the insulating polymer foam 12. The corner pillars 14 are, for example, plywood or plastic. The corner pillars 14 make it possible to take up part of the compression load in service and to limit the crushing and creep of the foam. Such corner pillars 14 have a coefficient of thermal contraction different from that of the first layer of insulating polymer foam 12. Also, when the tank is cold, the deflection of the secondary insulating panel 7 is lower at the level of the corner pillars 14 than in other areas. This further increases the effects of height differences or walking at the corner areas of the secondary insulating panels 7.

Furthermore, the secondary insulating panel 7 has recesses 15, 16 at its corner areas to receive anchoring devices 8 which will be detailed later. The secondary insulating panel 7 comprises, from the bottom plate 9 to the intermediate plate 10, a first recess 15 intended to allow the passage of a rod 17 of the anchoring device 8. Above the intermediate plate 10, the secondary insulating panel 7 has a second recess 16. The second recess 16 has dimensions greater than those of the first recess 15 so that the intermediate plate 10 projects beyond the second layer of insulating polymer foam 13 and the plate cover 1 1. Thus, the intermediate plate 10 forms at the corner areas of the panel secondary insulator 7 a support zone 18 intended to cooperate with a secondary support plate 19 of the anchoring device 8.

Furthermore, the cover plate 1 1 has a counterbore 20 at these four corner areas. Each counterbore 20 is intended to receive a force distribution plate 21 of the anchoring device 8, described below. The counterbores 20 have a thickness substantially similar to that of the force distribution plate 21 so that the force distribution plate 21 is flush with the upper surface of the cover plate 11. The cover plate 1 1 also has grooves 22 for receiving weld supports.

The structure of the secondary insulating panel 7 is described above by way of example. Also, in another embodiment, the secondary insulating panels 7 may have another general structure, for example that described in document WO2012 / 127141. The secondary insulating panels 7 are then produced in the form of a box comprising a bottom plate, a cover plate and carrier webs extending, in the thickness direction of the wall 1 of the tank, between the bottom plate and the cover plate and delimiting a plurality of compartments filled with an insulating lining, such as perlite, glass wool or rock wool.

In another embodiment, the secondary thermally insulating barrier 2 comprises secondary insulating panels 7 having at least two different types of structure, for example the two aforementioned structures, depending on their location in the tank. Thus, in certain zones of the wall 1 of the tank, the adjacent secondary insulating panels 7 are capable of exhibiting different behaviors when they are subjected to thermal gradients, which is liable to amplify the phenomena of height differences between the adjacent corners. secondary insulating panels 7.

Returning to FIG. 1, it can be seen that the secondary sealing membrane 4 comprises a continuous ply of strakes 23, metallic, with raised edges. The strakes 23 are welded by their raised edges on parallel welding supports which are fixed in the grooves 22 formed on the cover plates 11 of the secondary insulating panels 7. The strakes 23 are, for example, produced Invar ®: that is to say an alloy of iron and nickel whose coefficient of expansion is typically between 1, 2.10 ⁶ and 2.10 ⁶ K ¹ .

The primary thermally insulating barrier 5 comprises a plurality of primary insulating panels 24 which are anchored to the support structure 3 by means of the above-mentioned anchoring devices 8. The primary insulating panels 24 have a generally parallelepiped shape. In addition, they have dimensions identical to those of the secondary insulating panels 7 with the exception of their thickness along the thickness direction of the wall 1 of the tank which is likely to be different, and in particular smaller. Each of the primary insulating panels 24 is positioned in line with one of the secondary insulating panels 7, in alignment with the latter along the thickness direction of the wall 1 of the tank.

In relation to FIG. 3, the structure of a primary insulating panel 24 according to one embodiment is observed. The primary insulating panel 24 has a multilayer structure similar to that of the secondary insulating panel 7 in FIG. 2. Also, the primary insulating panel 24 successively comprises a bottom plate 25, a first layer of insulating polymer foam 26, an intermediate plate 27 , a second layer of insulating polymer foam 28 and a cover plate 29. The insulating polymer foam can in particular be a polyurethane-based foam, optionally reinforced with fibers.

The primary insulating panel 24 has recesses 30 at its corner areas so that the bottom plate 25 projects beyond the first layer of insulating polymer foam 26, at the intermediate plate 27, at the second layer of insulating polymer foam 28 and to the cover plate 29. Thus, the bottom plate 25 forms at the corner areas of the primary insulating panel 24 a support area 31. This support area 31 receives a shim 32 described more in detail below. In the embodiment illustrated in FIG. 3, the shim 32 has a shape similar to that of the support zone 31. This shim 32 is intended to cooperate with a primary support plate 33 of the anchoring device 8.

The bottom plate 25 has grooves 34 intended to receive the raised edges of the strakes 23 of the secondary sealing membrane 4. In the embodiment illustrated in FIGS. 1 and 3, the cover plate 29 also has grooves 35 to receive welding supports (not shown). The structure of the primary insulating panel 24 is described above by way of example. Also, in another embodiment, the primary insulating panels 24 may have another general structure, for example that described in document WO2012 / 127141.

In another embodiment, the primary thermally insulating barrier 5 comprises primary insulating panels 24 having at least two different types of structure, for example the two aforementioned structures, depending on their location in the tank.

Returning to FIG. 1, it can be seen that the primary sealing membrane 6 comprises a continuous sheet of metal strakes 36 with raised edges. The strakes 33 are welded by their raised edges on parallel welding supports which are fixed in the grooves formed on the cover plates 29 of the primary insulating panels 24. Although the description is made in the context of a waterproofing membrane primary 6 made using metal strakes 36, the primary sealing membrane could be made using other techniques. For example, the primary waterproofing membrane could be produced using corrugated metal plates as described for example in document FR2691520.

As shown in FIG. 1, the anchoring devices 8 are positioned at the four corners of the primary 24 and secondary insulating panels 7. Each stack of a secondary insulating panel 7 and a primary insulating panel 24 is anchored to the supporting structure 3 by means of four anchoring devices 8. In addition, each anchoring device 8 cooperates with the corners of four adjacent secondary insulating panels 7 and with the corners of four adjacent primary insulating panels 24.

In connection with FIGS. 4 and 5, the structure of an anchoring device 8 is observed.

The anchoring device 8 comprises a socket 37 whose base is welded to the support structure 3 in a position which corresponds to a clearance at the corner areas of four adjacent secondary insulating panels 7. The socket 37 houses a nut (not shown) into which the lower end of a rod 17 is screwed. The rod 17 passes between the adjacent secondary insulating panels 7.

The rod 17 passes through a bore formed in an insulating plug

38 intended to ensure continuity of the secondary thermal insulation at the level of the anchoring device 8. The insulating plug 38 has, in a plane orthogonal to the thickness direction of the wall 1 of the tank, a cross-shaped section which is defined by four branches. Each of the four branches is inserted into a gap formed between two of the four adjacent secondary insulating panels 7.

The anchoring device 8 further comprises a secondary support plate

19 which is supported in the direction of the support structure 3 against the support area 18 formed in each of the four adjacent secondary insulating panels 7 in order to retain them against the support structure 3. In the embodiment shown, the plate secondary support 19 is housed in the second recess 16 formed in the second layer of insulating polymer foam 13 of each of the secondary insulating panels 7 and is in abutment against an area of the intermediate plate 10 which forms the support area 18.

A nut 39 cooperates with a thread formed at the upper end of the rod 17 so as to retain the secondary support plate 19 on the rod 17.

In the embodiment shown, the anchoring device 8 also comprises one or more elastic washers 40, of the Belleville type. The elastic washers 40 are threaded on the rod 17 between the nut 39 and the secondary support plate 19, which ensures elastic anchoring of the secondary insulating panels 7 on the support structure 3. In addition, advantageously , a locking member 41 is locally welded to the upper end of the rod 17, so as to fix the nut 39 in position on the rod 17.

The anchoring device 8 also comprises a force distribution plate 21, an upper plate 42 and a spacer 43 which are fixed to the secondary support plate 19.

The force distribution plate 21 is housed in each of the countersinks

20 provided in the cover plates 1 1 of the four insulating panels secondary 7 adjacent. The force distribution plate 21 is therefore positioned between the cover plates 1 1 of each of the four secondary insulating panels 7 and the secondary sealing membrane 4. The force distribution plate 21 aims to attenuate the phenomena of height differences between the corners of adjacent secondary insulating panels 7. Also, the force distribution plate 21 makes it possible to distribute the stresses likely to be exerted on the secondary sealing membrane 4 and the primary insulating panels 24 in line with the corner areas of the secondary insulating panels 7. Consequently, the plate distribution of forces 21 makes it possible to limit the phenomena of punching the bottom plates 25 of the primary insulating panels 24 and of punching and compacting the layers of insulating polymer foam 26, 28 of the primary insulating panels 24 in line with the corner areas of the panels secondary insulation 7.

The force distribution plate 21 is advantageously made of a metal chosen from stainless steel, iron and nickel alloys, such as invar, the coefficient of expansion of which is typically between 1, 2.10 ⁶ and 2.10 ⁶ K ¹ and the iron and manganese alloys whose coefficient of expansion is less than 2.10 ⁵ K ¹ , typically of the order of 7.10 ⁶ K ¹ . The force distribution plate 21 has a thickness of between 1 and 7 mm, preferably between 2 and 4 mm, for example of the order of 3 mm. The force distribution plate 21 advantageously has a square shape whose dimension on one side is between 100 and 250 mm, for example of the order of 150 mm.

The upper plate 42 is arranged below the force distribution plate 21 and has dimensions smaller than that of the force distribution plate 21 so that the force distribution plate 21 completely covers the upper plate 42. The upper plate 42 is housed in the recesses 16 formed in the corner zones of the secondary insulating panels 7, in line with the support zones 17, that is to say in the embodiment shown in FIG. 5, in the recesses 16 formed in the second layer of insulating polymer foam 13 of the secondary insulating panels 7.

The upper plate 42 has a threaded bore 44 in which is mounted a threaded base of a stud 45 intended for the anchoring of the primary insulating panels 24. In order to allow the fixing of the stud 45 to the upper plate 42, the force distribution plate 21 also has a bore, arranged opposite the threaded bore of the upper plate 42, and thus allowing the stud 45 to pass through the force distribution plate 21.

The upper plate 42 has a general shape of a rectangular parallelepiped comprising two large opposite faces which are parallel to the support structure 3 of the wall 1 and four faces which connect the two large faces and extend parallel to the thickness direction of the tank wall 1. In the embodiment illustrated in FIG. 4, the four faces which extend parallel to the thickness direction of the wall 1 of the tank are connected by fillets 46. This makes it possible to avoid the presence of a sharp angle and contributes to further limiting the punching phenomena of the bottom plates 25 of the primary insulating panels 24 by limiting the stress concentrations.

In one embodiment, the upper plate 42 and the force distribution plate 21 are formed in a single piece.

The spacer 43 is disposed between the secondary support plate 19 and the upper plate 42 and thus serves to maintain a spacing between the secondary support plate 19 and the upper plate 42. In the embodiment illustrated in Figures 4 , the spacer 43 has chamfers 47 in order to fit into the bulk, seen in the thickness direction of the wall 1 of the tank, of the upper plate 42. In other words, the upper plate 42 completely covers the spacer 43.

In the embodiment illustrated in FIG. 5, the anchoring device 8 differs from the anchoring device 8 illustrated in FIG. 4 in that the spacer 43 has a section, in a plane orthogonal to the thickness direction of the wall 1 of the tank, devoid of chamfers, which facilitates its manufacture. Similarly (not shown), the upper plate 42 could be devoid of leaves.

The spacer 43 is advantageously made of wood, which makes it possible to limit the thermal bridge towards the support structure 3 at the level of the anchoring device 8. The spacer 43 has an inverted U shape so as to define between the two branches of the U a central housing 48. The central housing 48 receives the upper end of the rod 17, the locking member 41, the nut 39 and the washers elastic 40. The spacer 43 is also housed in the recess 16 formed, in line with the bearing surface 18.

The locking member 41 has a square or rectangular shape, the diagonal of which has a dimension greater than the dimension of the central housing 48 between the two branches of the U, which makes it possible to block the rod 17 in rotation relative to the spacer 43 and thus prevents the rod 17 from disengaging from the nut 39.

In order to fix the force distribution plate 21, the upper plate 42, the spacer 43 and the secondary support plate 19 to each other, the aforementioned elements are each provided with two bores through each of which passes a screw 49, 50. The bores provided in the secondary support plate 19 each have a thread cooperating with one of the screws 49, 50 so as to secure the abovementioned elements to each other.

Furthermore, the stud 45 crosses a bore formed through a strake 23 of the secondary sealing membrane 4. The stud 45 has a flange 51 which is welded at its periphery, around the bore, to ensure the sealing of the secondary sealing membrane 4. The secondary sealing membrane is therefore sandwiched between the flange 51 of the stud 45 and the force distribution plate 21.

The anchoring device 8 also comprises a primary support plate 33 which is supported in the direction of the support structure 3 on the wedge 32. In the embodiment illustrated in Figures 3 and 5, the corners of each insulating panel primary 24 comprise a respective shim 32, said shim 32 covering the support area 31 formed by the bottom plate 25. Thus, the primary support plate 33 presses on the shims 32 of four adjacent primary panels 24, said shims 32 being in abutment against the bearing zones 31 formed in the corresponding corners of said four adjacent primary insulating panels 24 so as to retain said primary insulating panels 24 against the support structure 3. In the embodiment shown, each bearing zone 31 is formed by an overhanging part of the bottom plate 25 of one of the primary insulating panels 24. The primary support plate 33 is housed in the recesses 30 formed in the areas of corner of the primary insulating panels 24, to the right of the support zones 31. A nut 52 cooperates with a thread formed at the upper end of the stud 45 so as to secure the primary support plate 33 on the stud 45. In the embodiment shown, the anchoring device 8 further comprises a single elastic washer 53, of the Belleville type, threaded on the stud 45 between the nut 52 and the primary support plate 33.

Furthermore, an insulating plug 54, illustrated in FIG. 5, is inserted above the anchoring device 8 in the recesses 30 formed at the corner areas of four adjacent primary insulating panels 24 so as to ensure continuity of the primary thermally insulating barrier 5 at the anchoring device 8. In addition, a closure plate (not shown), made of wood, ensures a flatness of the support surface of the primary sealing membrane 6. The closure plate is received in counterbores formed at the corner areas of the primary insulating panels 24.

In order to keep the primary insulating panels 24 anchored on the support structure 3, it is necessary to keep the support of the primary support plate 33 on the wedges 32 despite the differences in behavior of the anchoring device 8 and the panels primary insulators 24. In particular, it is necessary to maintain this support despite the differences in behavior in thermal contraction of the anchoring device 8 and of the primary insulating panels 24.

To maintain the support of the primary support plate 33 on the shims 32, the embodiment illustrated in FIG. 5 provides for the use of a shim 32 and a bottom plate 25 selected to present a coefficient of thermal contraction in the direction of thickness of the vessel wall adapted so that the assembly formed by the bottom plate 25 and the shim 32 has a coefficient of overall thermal contraction lower than that of the anchoring device 8. In the following description, references to the thermal contraction coefficient are made for a thermal contraction coefficient along a thickness direction of the tank wall.

As part of a bottom plate 25 made of a material having a coefficient of thermal contraction greater than the coefficient of thermal contraction of the stud 45 and of the primary support plate 33, the shim 32 is selected so as to have a thermal contraction coefficient lower than the thermal contraction coefficient of the stud 45 and the primary support plate 33. In addition, the bottom plate 25 and the shim 32 are dimensioned so that the assembly formed by said bottom plate 25 and the shim 32 has a lower overall thermal contraction coefficient, preferably slightly lower and ideally equal to the overall thermal contraction coefficient of the stud 45 and of the primary support plate 33. Thus, a surface external of the primary support plate 33 is held in abutment on an internal surface of the shim 32 during a temperature change in the tank.

In fact, under the effect of this change in temperature, the displacement of the external surface of the primary support plate 33 is slightly greater, ideally substantially identical, to the displacement of the external surface of the wedge 32 because the assembly formed by the bottom plate 25 and the shim 32 has an overall thermal contraction coefficient lower than the thermal contraction coefficient of the stud 45 and of the primary support plate 33.

This behavior in thermal contraction therefore makes it possible to retain the support of the primary support plate 33 on the shim 32 in a reliable and stable manner despite the absence or the limited number of Belleville washers 50 on the stud 45.

In one example, the bottom plate 25 of the primary insulating panels 24 is made of plywood with fibers oriented in a plane parallel to the support structure 3 and a thickness of 9mm. Such a bottom plate 25 thus has a coefficient of thermal contraction of the order of 3.65E-05. In the context of a stud 45 having a coefficient of thermal contraction on the order of 1.60E-05, the shim 32 can be produced so as to have a coefficient of thermal contraction on the order of 5.50E-06.

Such a wedge 32 is for example made of plywood but, unlike the bottom plate 25, has an orientation of the plywood fibers perpendicular to the porous structure, that is to say in a plane parallel to the direction of thickness of the tank wall.

In this case, the shim 32 then has a thickness greater than 17.6mm and the stud 45 and the primary support plate 33 are dimensioned so that that the external surface of the primary support plate 33 is positioned 26.6 mm from the external face of the bottom plate. In fact, in such an example, a temperature variation of 90 ° C., the difference in displacement between the external surface of the primary support plate 33 and the internal surface of the wedge 32 is of the order of 2.70E- 05, the external surface of the primary support plate 33 moving slightly more than the internal surface of the shim 32 so that the support of the primary support plate 33 on the shim 32 is retained despite the change in temperature . Similarly, for a temperature variation of 183 ° C, the difference in displacement between the external surface of the primary support plate 33 and the internal surface of the shim 32 is of the order of 5.49E-05, the surface external of the primary support plate 33 moving slightly more than the internal surface of the shim 32 so that the support of the primary support plate 33 on the shim 32 is retained despite the change in temperature.

Wedge thicknesses 32 of 18, 19 or 20 mm, and a stud 45 and a primary support plate 33 dimensioned so that the external surface of the primary support plate is at a distance of 27, 28 respectively or 29 mm would also make it possible to maintain the tightening of the primary support plate 33 on the shim 32.

However, in order not to damage the shim 32 and / or the bottom plate 25, the assembly formed by the bottom plate 25 and the shim 32 must not have an overall contraction coefficient too far from the thermal contraction coefficient of the assembly formed by the stud 45 and the primary support plate 33. In fact, too great a difference in thermal contraction coefficient could cause a displacement and therefore an excessive support of the primary support plate 33 on the shim 32.

Thus, in the example given by way of illustration above, a bottom plate 25 made of plywood 9 mm thick with a coefficient of thermal contraction of 3.65E-05 and a stud 45 with a coefficient of thermal contraction 1.60E-05, the shim 32 with a coefficient of thermal contraction of 5.50E-05 must not have a thickness greater than 68mm under penalty of seeing the primary support plate 33 exert too great a support. In other words, in this embodiment, the shim 32 must have a thickness of between 17.6 mm and 68mm to maintain the support of the primary support plate 33 without damaging the bottom plate 25.

Thus, the shim 32 is made of a selected material and / or is arranged in order to obtain a shim 32 having a coefficient of thermal contraction in the thickness direction of the wall of the tank lower than that of the bottom plate 25 on which it rests. In addition, this shim 32 is dimensioned in said thickness direction of the tank wall so that the assembly formed by the bottom plate 25 and the shim 32 exhibits a behavior in thermal contraction close to that of the device d anchorage 8. More particularly, the behavior in thermal contraction of this assembly allows the maintenance of the cooperation between the wedge 32 and the primary support plate 33 despite the temperature variations, that is to say preventing this assembly only contracts the anchoring device 8.

FIG. 6 shows an alternative embodiment of the shim 32 in which the shim 32 is dimensioned so as to jointly cover two support zones 31 with two adjacent primary insulating panels 24. Such a wedge 32 makes it possible to limit the mounting operations in the tank and therefore facilitates the manufacture of the tank. This wedge 32 has a central recess 55 allowing the passage of the stud 45.

In addition, as illustrated in FIG. 7, this shim 32 is dimensioned so as to preserve a space between the first layer of insulating polymer foam 26 and the shim 32, allowing the circulation of gas in the primary thermally insulating barrier. In other words, the shim 32 has dimensions such that it does not entirely cover the bearing zones 31 of the adjacent primary insulating panels 24 in order to preserve a space allowing the circulation of gas such as an inert gas in the primary thermally insulating barrier while ensuring sufficient cooperation with the primary support plate 33 and with said support zones 31 to allow the anchoring of said primary insulating panels 24.

Figures 8 to 11 show other embodiments of the shim 32 also allowing the circulation of gas in the thermally insulating barrier primary by providing spaces between the shim 32 and the first layer of insulating polymer foam 26.

FIG. 13 illustrates a tank wall 101 according to a second embodiment. Elements identical or analogous to the elements of FIGS. 1 to 1 1 bear the same reference number as these increased by 100 and will only be described in so far as they differ from them.

The embodiment illustrated in FIGS. 13 and 14 differs from the embodiment illustrated in FIGS. 1 to 5 in that the primary insulating panels 124 are superimposed offset from the secondary insulating panels 107. Thus, the corner areas of the primary insulating panels 124 are not located to the right of the corner areas of the secondary insulating panels 107 but to the right of a central portion of the cover plate 1 11 of corresponding secondary insulating panels 107.

In the illustrated embodiment, the primary insulating panels 124 are offset from the secondary insulating panels 107 in the two directions of the plane by half the length of a secondary insulating panel 107. The amplitude of the offset could be different and the corner areas of the primary insulating panels 124 could be elsewhere on the cover plate 11 of a secondary insulating panel 107, but preferably at a distance from the raised edges of the strakes 123 so as not to interfere with them. The magnitude of the offset can be different in the two directions of the plane.

In addition, in the embodiment illustrated in FIGS. 13 and 14, the secondary 107 and primary 124 insulating panels differ from the secondary 7 and primary 24 insulating panels described above in that they do not comprise an intermediate plate 10, 27. Thus, a secondary insulating panel 107 comprises a bottom plate 109, a layer of secondary insulating polymer foam 156 and a cover plate 1 11. Likewise, a primary insulating panel 124 comprises a bottom plate 125, a layer of primary insulating polymer foam 157 and a cover plate 129. In addition, the bottom plate 109 projects from the layer of secondary insulating polymer foam 156 and the cover plate 11 11 on the sides of the secondary insulating panels 107. In this second embodiment, the anchoring devices 8 are separated into two distinct parts, a first part forming a secondary retaining member 158 cooperating with secondary insulating panels 107 and a second part forming a primary retaining member 159 cooperating with primary insulating panels 124. Due to the offset of the corner areas of the primary insulating panels 124 relative to the corner areas of the secondary insulating panels 107, the secondary retaining members 158 are separated and offset from the primary retaining members 159.

The secondary retainer 158 can be made in a variety of ways. For example, the secondary retaining member 158 may include a threaded stud anchored to the support structure on which is mounted a secondary support plate retained on the stud by a nut. This secondary support plate is then supported on the bottom plate 109 of the secondary insulating panel 107, directly or by means of a shim resting on the projecting part of the bottom plate 109. An insulating plug in order to ensuring the continuity of the thermal insulation can be inserted into the chimney formed by the recesses of the adjacent secondary insulating panels 107. Similarly, a closure plate, for example of plywood, can be housed in a counterbore of the cover plate 1 11 of the adjacent secondary insulating panels 107 to ensure the continuity of the support surface formed by the cover plates 1 11 .

In an alternative embodiment not shown, the secondary insulating panels 107 are identical to the secondary insulating panels 7 described above. In this variant, the secondary retaining member 158 may have a structure similar to that described above for the anchoring device 8 from which all the elements arranged above the force distribution plate 21 will have been removed. In this case, the force distribution plate 21 and the counterbore 20 intended to receive it can also be eliminated.

The secondary retaining members 158 can be in various numbers ranging for example from 2 to 5 per secondary insulating panel 107 and placed for example at the corners of the secondary insulating panels 107 and / or in a gap between two secondary insulating panels 107 either according to the first direction either according to the second direction. Other embodiments of the secondary retaining member are described in WO-A-2013093262.

In FIG. 14, the primary retaining member 159 comprises an anchoring plate 160, for example having a square or circular contour, which is fixed in a countersink formed in the surface of the cover plate 11 1 facing the layer of secondary insulating polymer foam 156, for example by gluing. The anchoring plate 160 has a threaded hole opening on the upper surface of the cover plate 11 1, that is to say on the surface of the cover plate 1 11 facing the inside of the tank. A stud 145 identical to the stud 45 described above is screwed into the threaded hole of the plate 160.

Furthermore, the primary retaining member 159 has characteristics similar to those described above with reference to FIGS. 1 to 5 for the parts of the anchoring device 8 cooperating with the stud 45. Thus, the primary retaining member 159 comprises a primary support plate retained on the stud 145 by a nut and, optionally, an elastic washer. This primary retaining member 159 cooperates with the bottom plate 125 and a wedge similar to that described above between on the one hand the anchoring device 8 and, on the other hand, the bottom plate 25 and the shim 32. In other words, the primary retaining member 159 on the one hand, and the bottom plate 125 and the shim, on the other hand, have selected thermal contraction coefficients and are dimensioned so as to retain the support of the primary support plate of the primary retaining member 159 on the shim under the effect of temperature changes in the tank.

Referring to Figure 12, a cutaway view of an LNG carrier 70 shows a sealed and insulated vessel 71 of generally prismatic shape mounted in the double hull 72 of the vessel. 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 to transfer an LNG cargo from or to the tank 71.

FIG. 12 represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipe 76 and a shore installation 77. The loading and unloading station 75 is a fixed offshore installation comprising an arm mobile 74 and a tower 78 which supports the mobile arm 74. The mobile arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading / unloading pipes 73. The movable arm 74 can be adjusted to suit all LNG carrier sizes . 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 submarine pipe 76 to the loading or unloading station 75. The submarine 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 "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

1. Sealed and thermally insulating tank for storing a fluid comprising a tank wall (1, 101) having successively in a thickness direction of the tank wall, from the outside towards the inside of the tank, a thermally insulating barrier (5, 105) intended to be anchored to a support structure (3, 103) and a sealing membrane (6, 106) which rests against the thermally insulating barrier (5, 105),

wherein the thermally insulating barrier (5, 105) comprises insulating panels (24, 124) of parallelepipedal shape juxtaposed and intended to be anchored on the supporting structure (3, 103), said insulating panels (24, 124) having a plate bottom (25, 125) and an insulating pad (26, 28, 157), the bottom plate (25, 125) defining a bearing surface (31) projecting laterally from the insulating pad (26, 28, 157 ), said bearing surface (31) being turned towards the interior of the tank, a shim (32) being arranged on said bearing surface (31), said shim (32) having an internal surface facing the inside the tank, in which anchoring devices intended to be fixed to the support structure (3, 103) between the insulating panels (24, 124) cooperate with said insulating panels (24, 124), said anchoring devices being intended to retain the insulating panels (24, 124) against the struct ure carrier (3, 103);

wherein at least one of the anchoring devices (45, 145, 159) comprises a support member (33) having an external face facing the shim (32), said support member (33) being configured so that said external face presses on the internal face of the wedge (32) in the direction of the bearing surface (31),

and wherein one of the shim (32) and the bottom plate (25) has a coefficient of thermal contraction in the thickness direction of the vessel wall greater than the coefficient of thermal contraction of said anchoring device (45 , 145, 159) in said thickness direction and the other among the shim (32) and the bottom plate (25) has a coefficient of thermal contraction in said direction of thickness less than the coefficient of thermal contraction of the device d anchoring (45, 145, 159) in said thickness direction.

2. Tank according to claim 1, wherein the coefficient of thermal contraction of the wedge (32) is less than the coefficient of thermal contraction of the bottom plate (25, 125).

3. Tank according to one of claims 1 to 2, wherein the shim (32) and the bottom plate (25, 125) have a respective dimension in the thickness direction configured so that the support member ( 33) exerts support on the internal face of the wedge (32) in the direction of the support surface (31) during a decrease in temperature from ambient temperature.

4. Tank according to one of claims 1 to 3, wherein the dimensional variation of the anchoring device (45, 145, 159) in the thickness direction of the vessel wall is higher than the dimensional variation in said thickness direction of the assembly formed by the bottom plate (25, 125) and the shim (32) when the temperature changes from 20 ° C to -163 ° C.

5. Tank according to one of claims 1 to 4, wherein the difference in dimensional variation difference in the thickness direction of the tank wall during a temperature change from 20 ° C to -163 ° C between the anchoring member (45, 145, 159) and the assembly formed by the bottom plate (25, 125) and the shim (32) is between 5.50E-05 mm and 9.69E-02 mm.

6. Tank according to one of claims 1 to 5, in which the shim (32) is made of plywood and is arranged so as to have fibers oriented in a plane parallel to the thickness direction of the tank wall,

and in which the bottom plate (25, 125) is made of plywood and is arranged so as to have fibers oriented in a plane perpendicular to the thickness direction of the tank wall.

7. Tank according to one of claims 1 to 6, in which the shim (32) has a coefficient of thermal contraction in the thickness direction of the wall of the tank of between 4E-06 K ¹ and 8E-06 K ¹ .

8. Tank according to one of claims 1 to 7, in which the bottom plate (25, 125) has a coefficient of thermal contraction in the thickness direction of the wall of the tank of between 3 E-05 K ¹ and 4 E-05 K ¹ .

9. Tank according to one of claims 1 to 8, in which the anchoring device (45, 145, 145) has a coefficient of thermal contraction in the thickness direction of the wall of the tank of between 1.4E-05 K ¹ and 1.8E-05 K ¹ .

10. Tank according to one of claims 1 to 9, wherein, in a thickness direction of the tank wall, the bottom plate (25, 125) has a thickness of 9mm and the shim has a thickness between 17.6mm and 68mm.

11. Tank according to one of claims 1 to 10, wherein the shim (32) rests on at least 50% of the bearing surface (31) of the insulating panel (24, 124).

12. Tank according to one of claims 1 to 11, in which the shim

(32) is arranged on the bearing surface (31) of two adjacent insulating panels (24, 124) so that the bearing member (33) bears on said wedge (32) in the direction of the surfaces d 'support (31) of said two adjacent insulating panels (24, 124).

13. Tank according to any one of claims 1 to 12, in which the thermally insulating barrier is a primary thermally insulating barrier, the insulating panels are primary insulating panels, the waterproofing membrane is a primary waterproofing membrane and l 'support member (33) is a primary support member, the vessel wall further comprising a secondary thermally insulating barrier and a secondary sealing membrane intended to be interposed between the primary thermally insulating barrier and the supporting structure.

14. Tank according to one of claims 1 to 13, wherein at least one of the insulating panels comprises a cover plate, the insulating lining being interposed between the bottom plate and the cover plate, said insulating panel further comprising a intermediate plate disposed between the bottom plate and the cover plate, the insulating packing comprising a first layer of insulating polymeric foam sandwiched between the bottom plate and the intermediate plate and a second layer of insulating polymeric foam sandwiched between the intermediate plate and cover plate, and in which recesses are provided in the layers of insulating polymeric foam and in the intermediate plate and the cover plate so that the bottom plate projects beyond said layers of insulating polymeric foam and the intermediate and bottom plates thus the bearing surface on the bottom plate.

15. Ship (70) for transporting a fluid, the ship comprising a double hull (72) and a tank (71) according to any one of claims 1 to 14 disposed in the double hull (72).

16. A method of loading or unloading a ship (70) according to claim 15, in which a fluid is conveyed through insulated pipes (73, 79, 76, 81) from or to a floating or terrestrial storage installation ( 77) to or from the vessel (71).

17. Transfer system for a fluid, the system comprising a ship (70) according to claim 15, insulated pipes (73, 79, 76, 81) arranged so as to connect the tank (71) installed in the hull of the ship to a floating or terrestrial storage installation (77) and a pump for driving a fluid through the insulated pipes from or to the floating or terrestrial storage installation to or from the vessel of the ship.