Liquefied gas storage facility having polygonal support structure

Abstract

The invention relates to a liquefied gas storage installation (1) comprising: a load-bearing structure (10) having a bottom wall (21) and a vertical load-bearing wall (12) being composed of N vertical load-bearing panels (14);and a tank comprising a bottom wall (21) and a vertical wall (22), said bottom wall (21) comprising a plurality of angular sectors, the corrugated watertight membrane (70, 170) of each angular sector (25) having first undulations (72), the corrugated watertight membrane (70, 170) of each angular sector (25) comprising a plurality of metal plates (71) being arranged to form crown portions (75), the crown portions (75) being made up of a set of whole metal plates, in which the first undulations (72) present on the crown portions (75) are in a total number which increases in the direction of the vertical wall (22), said total number being increased only every M successive crown portions (75), with M a natural number greater than or equal to 2.;

Description

Technical field

[0001] The invention relates to a liquefied gas storage facility and to a tracing method for the construction of this facility. More particularly, the liquefied gas storage facility comprises a supporting structure having a regular polygonal bottom wall. Technological background

[0002] Document FR-A-2912385 or FR-A-3121196 discloses a liquefied gas storage facility comprising a supporting structure having an internal space delimited by a bottom supporting wall and a sealed and thermally insulating tank installed in the internal space of the supporting structure. The tank comprises a bottom wall arranged on the bottom supporting wall and a vertical wall arranged on the vertical supporting wall.

[0003] The vertical wall has a plurality of vertical sections. The bottom wall has a plurality of sectors which are images of each other by rotation, and where said bottom wall has the shape of a regular polygon, each side of which corresponds to one of said vertical sections.

[0004] The number of vertical sections is for example chosen to be equal to 56.

[0005] The sealed and thermally insulating tank comprises a corrugated waterproof membrane intended to be in contact with a liquefied gas and a thermally insulating barrier located between the waterproof membrane and the supporting structure.

[0006] The waterproof membrane of the vertical wall comprises vertical corrugations. The waterproof membrane of the bottom wall comprises first corrugations spaced from each other by a wave pitch and oriented along a sector axis perpendicular to the vertical section connected to said angular sector. The corrugated waterproof membrane of each angular sector of the bottom wall comprises a plurality of rectangular metal plates welded together in a sealed manner so as to be arranged to form crown portions juxtaposed successively along the sector axis. A crown portion is called a set of whole metal plates. In other words, the edges of the crown portions are formed by edges of the metal plates. The crown portions located in the different angular sectors are connected together to form crowns around a central portion of the bottom wall.

[0007] In the prior art, an arrangement strategy by angular sector is applied which aims to link the wave pitch of the first undulations and the length of the metal plates, which defines a width of the crown portion, to the angle of the angular sector in order in particular to limit the number of different parts on an angular sector.

[0008] However, by varying the wave pitch and in particular when it increases, the arrangement strategy no longer allows for the maintenance of coherent angular sector angles and / or coherent lengths of the metal plates and thus reduces the number of possible solutions. Summary of the invention

[0009] An idea behind the invention is to improve the angular sector arrangement strategy of the bottom wall in order to maintain consistent angular sector angles and consistent sheet lengths, without complicating the arrangement.

[0010] An object of the invention is in particular to provide a membrane arrangement which allows the wave pitch to be greater than the length increment of the outer edge of the crown portion between two successive crowns. This length increment is close to the width of the crown portion multiplied by the angle of the sector.

[0011] According to one embodiment, the invention provides a liquefied gas storage installation comprising: a supporting structure having an internal space delimited by a bottom supporting wall and a vertical supporting wall, an outline of said bottom supporting wall having the shape of a regular polygon with N sides, N being an integer greater than or equal to 4, said vertical supporting wall being composed of N vertical supporting sections and forming a polygonal cylindrical surface having said regular polygon as a directrix, where each of the N sides of the polygon corresponds to an intersection of the bottom supporting wall with one of said vertical supporting sections; and a watertight tank installed in the internal space of the supporting structure, the watertight tank comprising a bottom wall arranged on the bottom supporting wall and a vertical wall arranged on the vertical supporting wall, said vertical wall being composed of N vertical sections, each vertical section of the vertical wall being fixed to one of the N vertical supporting sections,said bottom wall comprising a plurality of angular sectors which are images of each other by a rotation of a predetermined angle around a vertical axis, the predetermined angle being equal to k.360° / N, where k is a positive integer less than or equal to half of N, each angular sector of the bottom wall being connected to at least k of the N vertical sections of the vertical wall, the sealed tank comprising a corrugated sealed membrane intended to be in contact with a liquefied gas, in which the corrugated sealed membrane of each angular sector of the bottom wall has first corrugations oriented along a sector axis, the sector axis being perpendicular to a first vertical section selected from among the N vertical sections of the vertical wall, the first corrugations being spaced two by two with a regular wave pitch,in which the corrugated waterproof membrane of each angular sector of the bottom wall comprises a plurality of metal plates welded together in a sealed manner, the metal plates being arranged to form crown portions juxtaposed successively along the sector axis, each crown portion being made up of a set of whole metal plates and having an inner edge and an outer edge perpendicular to the sector axis, in which the first corrugations present on the crown portions are in a total number per crown portion which increases in the direction of the first vertical section, said total number per crown portion being increased only every M successive crown portions, with M a natural integer greater than or equal to 2. ,

[0012] In other words, the total number per crown portion is therefore constant per group of M successive crown portions.

[0013] Thanks to these characteristics, by increasing the total number of corrugations every M crown portions, it is possible to modulate by the factor M the arrangement strategy linking the regular wave pitch of the first corrugations and the width of the crown portions. Thus, depending on the higher or lower value of the regular wave pitch, the factor M makes it possible to obtain arrangement solutions having coherent values ​​for the angular sector angle and the size of the sheets constituting each crown portion in particular.

[0014] Indeed, in the prior art, the crown portion width L, the regular wave pitch P and the angular sector angle A are linked by the following equation: tan(A / 2)=P / L

[0015] The factor M is thus inserted into this equation in the following way: tan(A / 2)=P / (M*L)

[0016] In this way, when for example the regular wave pitch P is increased significantly compared to the prior art wave pitch, the factor M makes it possible to keep values ​​of the angular sector angle and the size of the metal plates within an admissible range.

[0017] According to embodiments, such a storage facility may comprise one or more of the following features.

[0018] According to one embodiment, the waterproof membrane comprises a first crown portion, a second crown portion and a third crown portion arranged successively along the sector axis and in the direction of the first vertical section, the total number of first undulations of the first crown portion being equal to N1, the total number of first undulations of the second crown portion being equal to N1, and the total number of first undulations of the third crown portion being equal to N2, with N1 and N2 being positive natural integers, for example with N2 equal to N1+2. This case corresponds to the factor M equal to 2.

[0019] According to one embodiment, the waterproof membrane comprises a first crown portion, a second crown portion, a third crown portion and a fourth crown portion arranged successively along the sector axis and in the direction of the first vertical section, the total number of first undulations of the first crown portion being equal to N1, the total number of first undulations of the second crown portion being equal to N1, the total number of first undulations of the third crown portion being equal to N1, and the total number of first undulations of the fourth crown portion being equal to N2, with N1 and N2 being positive natural integers, for example with N2 equal to N1+2. This case corresponds to the factor M equal to 3.

[0020] According to one embodiment, one or each crown portion comprises a plurality of rectangular metal plates.

[0021] According to one embodiment, the crown portions each have a width extending along the sector axis between the inner edge and the outer edge of the crown portion, said width being equal in several of said crown portions, in particular in successive crown portions along the sector axis.

[0022] According to one embodiment, the width of the crown portion located near a center of the bottom wall and / or the width of the crown portion located near the vertical wall is different from the width of the other crown portions, preferably the other crown portions being of identical width to each other.

[0023] According to one embodiment, the width of at least one of the crown portions is different from the equal width of said several crown portions, for example equal to an integer fraction of the equal width of said several crown portions.

[0024] According to one embodiment, the regular wave pitch is greater than the width of one of the crown portions multiplied by the predetermined angle.

[0025] According to one embodiment, N is even and preferably is greater than or equal to 4.

[0026] According to a particular embodiment, N is between 8 and 56. According to another particular embodiment, N is equal to 56. According to another particular embodiment, N is equal to 8.

[0027] The integer k is equal to the number of vertical sides of the vertical wall, divided by the number of angular sectors of the bottom wall of the tank. According to one embodiment, k is equal to 1 or 2.

[0028] According to one embodiment, the regular wave pitch is greater than or equal to 400 mm, preferably greater than or equal to 800 mm, preferably between 800 and 1200 mm, for example equal to 1000 mm.

[0029] For example, when N is equal to 56 and the width of one of the crown portions is equal to 3000mm, the regular wave pitch can be equal to 1020mm and the natural number M can be equal to 3.

[0030] According to one embodiment, one or each crown portion of an angular sector comprises at least one corrugated metal connecting plate located on a lateral edge of the crown portion, the corrugated metal connecting plates being configured to connect said crown portion with a crown portion of an adjacent angular section, the corrugated metal connecting plates of the crown portions being aligned with each other in a radial direction, the radial direction being inclined relative to the sector axis, preferably by an angle equal to half of the predetermined angle.

[0031] According to one embodiment, the waterproof membrane of the or each angular sector of the bottom wall comprises a radial corrugation located near an edge of the angular sector, the radial corrugation extending in the radial direction.

[0032] According to one embodiment, the first corrugations of the angular sector or of each angular sector comprise first whole corrugations extending from a junction between the bottom wall and the vertical wall to a central crown portion near a center of the bottom wall, and first partial corrugations which are interrupted by a wave interruption when said first partial corrugation crosses one of the corrugated metal connecting plates, the wave interruption being located at a distance from the radial corrugation.

[0033] According to one embodiment, the radial undulation of the angular sector is carried out on the corrugated metal connecting plates.

[0034] According to one embodiment, the corrugated metal connecting plate of a crown portion of rank A is identical to the corrugated metal connecting plate of a crown portion of rank A+B, with for example a rank A equal to 1 for a central crown portion located near a center of the bottom wall, where the rank is defined as being a natural whole number incremented by 1 moving away along the sector axis towards the vertical wall, A being a natural whole number greater than or equal to 1 and B being a natural whole number greater than or equal to 2.

[0035] According to one embodiment, the natural integer B is equal to the natural integer M.

[0036] According to one embodiment, the waterproof membrane of one or each angular sector of the bottom wall comprises second corrugations spaced from each other and extending at least partially perpendicular to the first corrugations.

[0037] According to one embodiment, the wave interruption of the first partial undulations is located between two adjacent second undulations.

[0038] According to one embodiment, a vessel for transporting a cold liquid product comprises a double hull and a aforementioned storage facility arranged in the double hull.

[0039] According to one embodiment, the invention also provides a transfer system for a cold liquid product, the system comprising the aforementioned vessel, insulated pipes arranged to connect the tank installed in the hull of the vessel to a floating or land-based storage structure and a pump for driving a flow of cold liquid product through the insulated pipes from or to the floating or land-based storage structure to or from the vessel's tank.

[0040] According to one embodiment, the invention also provides a method for loading or unloading a ship, in which a cold liquid product is conveyed through insulated pipes from or to a floating or land-based storage structure to or from the tank of the aforementioned ship. Brief description of the figures

[0041] 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 for illustrative and non-limiting purposes, with reference to the accompanying drawings.

[0042] There figure 1 represents a partial perspective and sectional view of a liquefied gas storage facility.

[0043] There figure 2 is a top view of the storage facility of the figure 1, allowing to distinguish the polygonal outline of the supporting structure from the figure 1 in an example of realization.

[0044] There figure 3 is a partial perspective view, from the interior of a liquefied storage installation according to the prior art, of the outer end of an angular sector of the bottom wall as well as portions of the vertical wall of the tank.

[0045] There figure 4 is a schematic perspective view, from inside the liquefied gas storage facility, of a portion of an angular sector of the bottom wall as well as portions of the vertical wall of the tank according to a first embodiment.

[0046] There Figure 5is a schematic perspective view, from inside the liquefied gas storage facility, of a portion of an angular sector of the bottom wall as well as portions of the vertical wall of the tank according to a second embodiment.

[0047] There figure 6 represents a top view of the waterproof membrane of a sector of the bottom wall of a tank installed in a liquefied gas storage facility, from inside the liquefied gas storage facility according to one embodiment.

[0048] There figure 7 is a view of detail VII of the figure 6 , more particularly representing a portion of a crown.

[0049] There figure 8 is a schematic cutaway representation of an LNG carrier vessel comprising a ship tank and a terminal for loading / unloading this tank. Description of the embodiments

[0050] As mentioned above, the invention relates to the production of a liquefied gas storage installation, which is referred to as 1 in the following description. The installation 1 is capable of storing a liquefied gas, in particular liquefied natural gas (LNG) at a temperature of approximately -162°C and at atmospheric pressure or other liquefied gases.

[0051] The installation 1 mainly comprises a supporting structure 10 and a sealed and thermally insulating tank 20 installed in the internal space of the supporting structure 10.

[0052] The supporting structure 10 is first described. The supporting structure 10 comprises a bottom supporting wall 11 and a vertical supporting wall 12.

[0053] The installation 1 may be designed to be located on land. The bottom load-bearing wall 11 is then typically horizontal, i.e. located in a plane perpendicular to the direction of the acceleration of gravity, represented in the figures by a vertical axis Z, within dimensional tolerances. The bottom load-bearing wall 11 may be located at ground level or possibly below ground level. The supporting structure 10 is for example made of concrete.

[0054] In the following, we consider more particularly the case of an installation 1 located on land and where the bottom load-bearing wall 11 is horizontal. It is nevertheless specified that the following description applies to any orientation of the bottom load-bearing wall 11 relative to the direction of the acceleration of gravity.

[0055] The outline of the bottom load-bearing wall 11 is intended to have the shape of a regular polygon with N sides, where N is an even integer greater than or equal to 4. An installation 1 where N is equal to 8 or 56 is more particularly interesting.

[0056] In addition to the bottom load-bearing wall 11, the load-bearing structure 10 comprises a vertical load-bearing wall 12. As can be better seen in the figure 1 , this vertical load-bearing wall 12 forms a polygonal cylindrical surface, having the polygon formed by the polygonal contour of the bottom load-bearing wall 11 as a director. The vertical load-bearing wall 12 extends in a vertical direction, that is to say in a direction perpendicular to the plane of the bottom load-bearing wall 11 within dimensional tolerances.

[0057] Referring to the Figures 1 and 2, the vertical load-bearing wall 12 is composed of N vertical load-bearing sections 14. Each of the N sides of the polygonal outline of the bottom load-bearing wall 11 corresponds to an intersection of the bottom load-bearing wall 11 with one of the vertical load-bearing sections 14. The vertical load-bearing sections 14 are connected to each other by edges 13, each edge 13 corresponding to a vertex of the polygonal outline of the bottom load-bearing wall 11.

[0058] An embodiment of a sealed and thermally insulating tank 20 which can be installed in the internal space of the supporting structure 10 is now described with reference to figures 1 to 8 The tank 20 comprises a bottom wall 21 arranged on the bottom load-bearing wall 11, and a vertical wall 22 arranged on the vertical load-bearing wall 12. In the same way as the bottom load-bearing wall 11, the bottom wall 21 has an outline having the shape of a regular polygon with N sides.

[0059] The vertical wall 22 is composed of N vertical sections 24. Each of the N sides of the polygonal outline of the bottom wall 21 corresponds to an intersection of the bottom wall 21 with one of the vertical sections 24. The vertical sections 24 are connected to each other by edges 23, each edge 23 corresponding to a vertex of the polygonal outline of the bottom wall 21.

[0060] The bottom wall 21 comprises a plurality of angular sectors 25. The sectors 25 are images of each other by rotation around a vertical axis, that is to say around an axis extending parallel to the vertical sections 24. This vertical axis passes through a point located in the vicinity of the geometric center of the bottom load-bearing wall 11. More precisely, the sectors 25 are images of each other by rotation of an angle equal to 4x180° / N, in the case where an angular sector 25 is connected to two vertical sections 24. Thanks to this exactly repeated structure, the same parts can be used to construct each angular sector 25.

[0061] In the example shown on the figures 3 And 6 , we have N = 56 and in the one represented figure 2 , we have N = 8. Only one sector 25 is represented on the figure 6 so as not to overload the drawing.

[0062] The bottom wall 21 and the vertical wall 22 comprise, going from the supporting structure 10 towards the interior space of the tank 20, a secondary thermally insulating barrier, a secondary sealed membrane, a primary thermally insulating barrier, and a primary sealed membrane 70 intended to be in contact with the liquefied gas contained in the tank 20. The bottom wall 21 and the vertical wall 22 can be made using modular elements. These modular elements can correspond to the GST ® technology marketed by the applicant. Reference may thus be made to document US 6,035,795 for the description of certain modular elements and to document WO2022200536 for other specific features of this technology not described here.

[0063] The primary waterproof membrane 70 of the bottom wall 21 is mainly made up of juxtaposed rectangular metal plates 71. On one of the lateral edges of the sectors 25, the primary waterproof membrane 70 further comprises connecting metal plates 71A. The connecting metal plates 71A are generally trapezoidal in shape and allow the connection between said sector 25 and a neighboring sector 25, thus making it possible to complete the primary waterproof membrane 70.

[0064] The primary waterproof membrane 70 is corrugated, in order to allow it to resist thermal contraction phenomena due to contact with the liquefied gas. More precisely, at the level of the bottom wall 21, the primary waterproof membrane 70 has at least corrugations 72 which are radiating, that is to say which are parallel to each other and extend along a sector axis X from the center of the tank 20 towards the vertical sides 24, the sector axis X being perpendicular to the vertical axis Z.

[0065] The first undulations 72 are spaced two by two with a regular wave pitch 26. In addition, the primary waterproof membrane 70 typically has second undulations 73 which are perpendicular to the first undulations 72. As shown in the figures and in particular in the figure 3, the plates 71, 71A each have portions of corrugations which, when the plates 71 and 71A are juxtaposed, together constitute the corrugations 72, 73.

[0066] As represented more particularly in figure 6 , the rectangular metal plates 71 are arranged to form crown portions 75 juxtaposed successively along the sector axis X. The connecting metal plates 71A extend each of the crown portions 75 so as to form, with all of the angular sectors, crowns all around the center of the bottom wall 21.

[0067] The corrugated metal connecting plates 71A of the crown portions 75 are aligned with each other in a radial direction. The radial direction is inclined relative to the sector axis X by an angle equal to half the angular sector angle 25. The waterproof membrane 70 of each angular sector 25 of the bottom wall 21 comprises a radial corrugation 77 located near an edge of the angular sector 25. The radial corrugation 77 extends in the radial direction and is produced on the corrugated metal connecting plates 71A.

[0068] There figure 3 , representing the prior art, shows, in perspective from inside the installation 1, the radially outer end of an angular sector 25 as well as portions of the vertical wall 22 of the tank 20. On the figure 3 , the vertical load-bearing sections 14 of the vertical load-bearing wall 12 are not shown.

[0069] At the level of the vertical wall 22, the metallic waterproof membrane 170 is mainly made up of juxtaposed rectangular metal plates 171 and has corrugations 172 which are vertical, that is to say which extend parallel to the vertical axis Z, parallel to the vertical load-bearing sections 14. The vertical corrugations 712 are spaced two by two with the regular wave pitch 26.

[0070] In addition, the metallic waterproof membrane 170 typically has horizontal corrugations 173 which are perpendicular to the vertical corrugations 172 and extend all the way around the tank 20. These metallic plates 171 each have portions of corrugations which, when the metallic plates 171 are juxtaposed, together constitute the corrugations 172, 173, as visible in figure 3 .

[0071] As illustrated in figures 3 to 5, each angular sector 25 is connected on the one hand to a complete vertical section 241 among the N vertical sections 24 and on the other hand to two vertical half-sections 242 each corresponding to half of a vertical section 24 among the N vertical sections 24 of the vertical wall 22. The complete vertical section 241 is centered on the angular sector 25 and the vertical half-sections 242 are located on either side of the complete vertical section 241. The angular sectors 25 are represented schematically in dotted lines on the figure 2 The sector axis X is here defined for each angular sector 25 as passing through the center of the tank 20 and perpendicular to the corresponding complete vertical section 241.

[0072] In the figure 3of the prior art, at the right of the complete vertical panel 241 and the vertical half-panels 242, the metal plates 71 and the metal connecting plates 71A are extended by metal joining plates 74 which carry portions of corrugations situated in the extension of the portions of corrugations of the metal plates 71, 71A, so as to extend the first corrugations 72 to corner joining pieces 69. These corner joining pieces 69 are more particularly described in document WO2022200536. Thus, in the prior art, the first corrugations 72 are extended to the complete vertical panel 241 and the vertical half-panels 242, so as to be continuously connected to the vertical corrugations 172 thanks to the corner joining pieces 69.

[0073] As explained in the introduction, with this type of prior art arrangement which imposes continuity between the first corrugations 72 of the bottom wall 21 and the vertical corrugations 172 of the vertical wall 22 with a regular corrugation pitch 26, the diameter delta between two storage installations following this arrangement is imposed by the addition or removal of a vertical corrugation 172 per vertical section 24 (and therefore of the associated first corrugation). The diameter delta is thus proportional to the regular corrugation pitch 26. The number of dimensional possibilities for such an installation is therefore limited, which is all the more problematic when the regular corrugation pitch 26 is of a large size.

[0074] THE Figures 4 and 5 represent two embodiments of the storage installation 1 in which, unlike the prior art illustrated in figure 3, by locally decorrelating vertical undulations 172 from their associated first undulations 72. In these diagrams, the solid lines represent the edges of the plates 71, 71A, 171 as well as the junction 28 between the bottom wall 21 and the vertical wall 22, while the dotted lines represent the undulations 72, 73, 77, 172, 173. Similarly, on the figure 6 , the solid lines represent the edges of the plates 71, 71A while the dotted lines represent the corrugations 72, 73, 77.

[0075] As visible on these Figures 4 and 5 , the continuity of the first undulations 72 with the vertical undulations 172 at the level of the complete vertical section 241 for each angular sector 25 is preserved in a manner analogous to the prior art. However, at the level of each vertical half-section 242, the vertical undulations 172 are discontinuous with the first undulations 72.

[0076] Indeed, for each angular sector 25, a singular wave pitch 27 smaller than the regular wave pitch 26 has been introduced between each vertical half-pan 242 and the complete vertical pan 241. The two vertical undulations 172 delimiting the singular wave pitch 27 thus comprise a singular undulation 174 located on the vertical half-pan 242, as visible in Figures 4 and 5 . Thus, the singular undulation 174 as well as the other vertical undulations 172 located between the singular undulation 174 and an outer edge of the half-panel are misaligned and therefore discontinuous with the first undulations 72 of the bottom wall 21.

[0077] The presence of the singular wave pitch 27 thus makes it possible to add intermediate dimensional solutions, which can be modulated with the value of the singular wave pitch 27, between two arrangements comprising only regular wave pitches 26.

[0078] A sudden stop of the first undulations 72 and the vertical undulations 172 at the junction between a vertical half-panel 242 and the bottom wall 21 may affect the flexibility of the waterproof membrane at this junction.

[0079] This is why it is advantageous to extend some of these first undulations 72 or vertical undulations 172 beyond this junction so that the latter overflows onto the vertical wall 22 or onto the bottom wall 21 respectively. This extension thus locally improves the flexibility of the waterproof member.

[0080] Thus, in the first embodiment illustrated in figure 4, the vertical undulations 172 of each vertical half-panel 242 are extended onto the bottom wall 21 by a vertical undulation extension 175 so that the vertical undulations 172 extend onto the bottom wall 21. This extension onto the bottom wall 21, however, remains localized. Indeed, the vertical undulation extensions 175 are interrupted on the bottom wall 21 at a distance from the second undulation 73 located near the junction between the bottom wall 21 and the vertical wall 22.

[0081] Similarly, in the second embodiment illustrated in Figure 5, those are the first undulations 72 which are extended on the vertical half-panel 242 by an extension of the first undulation 76 so that the first undulations 72 overflow onto the vertical wall 22. This extension on the vertical wall 22 remains, however, localized. Indeed, the extensions of the first undulation 76 are interrupted on the vertical wall 22 at a distance from the horizontal undulation 173 located near the junction between the bottom wall 21 and the vertical wall 22.

[0082] In an embodiment not illustrated, it is also conceivable that the first undulations 72 and the vertical undulations 172 are extended respectively on the vertical wall 22 and the bottom wall 21.

[0083] There figure 6represents the primary waterproof membrane 70 of an angular sector 25 of the bottom wall 21 seen from above according to one embodiment. As mentioned previously, the metal plates 71 of each angular sector 25 are arranged to form crown portions 75 juxtaposed successively along the sector axis X. The width of a crown portion 75 along the X axis corresponds for a large majority of the metal plates 71 to the length of these plates 71.

[0084] The metal plates 71 do not all have the same dimensions. Thus, in the example of the figure 6 , the metal plates 71 are divided into four different dimensions, namely: metal plates 71 of dimension “X1” comprising a first corrugation 72 and 3 second corrugations 73, one of which passes through the middle of the metal plate 71, metal plates 71 of dimension “X2” having in the example a length along the X axis equal to the length of the plates “X1”, and a width in a direction orthogonal to the X axis less than the width of the plates “X1”, metal plates 71 of dimension “X3” having a width equal to the width of the plates “X2”, the length being less than half the length of the plates “X2” so that the plates “X3” comprise a single second corrugation 73, metal plates 71 of dimension “X4”, having a width less than the width of the plates “X3” so as not to have a first corrugation 72 and a length such that the addition of the length of a plate “X3” and the length of a plate “X4” is equal to the length of an “X2” (or “X1”) plate..

[0085] In the example shown in figure 6 , the angular sector 25 comprises from the center of the bottom wall 21 towards the vertical wall 22: a first crown portion 75 comprising 2 metal plates of dimension “X3” side by side among the metal plates 71; a second crown portion 75 comprising two metal plates “X2” side by side; a third crown portion 75 comprising two metal plates “X1” side by side; a fourth crown portion 75 comprising two metal plates “X1” framed on each side by a plate “X4” followed by a plate “X3” along the X axis; a fifth crown portion 75 comprising two plates “X1” framed on each side by a plate “X2”; a sixth crown portion 75 with a pattern similar to the third crown portion with two additional plates “X1”; a seventh crown portion 75 with a pattern similar to the fourth crown portion 75 with two additional plates “X1”.

[0086] Similarly, the metal connecting plates 71A do not all have the same dimensions. These metal connecting plates 71A also have in the example of the figure 6 a pattern that repeats every three crown portions 75.

[0087] As presented previously, in the prior art, an arrangement strategy by angular sector 25 is applied which aims to link the wave pitch 26 of the first corrugations 72 and the length of the metal plates 71, or a width of the crown portion 75, to the angle of the angular sector 25 in order in particular to limit the number of different parts on an angular sector 25. Thus, the total number of first corrugations 72 present on the crown portions 75 which is increasing in the direction of the vertical wall 22 is increased at each successive crown portion 75 by two new first corrugations 72 on either side of the angular sector 25. Indeed, in the prior art, the crown portion width L, the regular wave pitch P and the angular sector angle A are linked by the following equation: tan(A / 2)=P / L

[0088] However, in the case of high wave pitch like that shown in the example illustrated in figure 6namely 1020mm wave pitch for 3000 x 1000mm plates, this arrangement strategy does not allow to maintain a consistent angular sector angle without significantly increasing the size of the plates 71.

[0089] Thus, in the embodiment shown figure 6 with a wave pitch of 1020 mm, the total number of first undulations 72 present on the crown portions 75 is increased only every three successive crown portions 75. In this example, the factor three thus makes it possible to keep values ​​of the angular sector angle 25 and the size of the metal plates 71 within an admissible range.

[0090] The first undulations 72 of each angular sector 25 thus comprise, as visible in figure 6, first whole corrugations 721 extending from a junction between the bottom wall 21 and the vertical wall 22 to a central crown portion 75 near a center of the bottom wall 21, and first partial corrugations 722 which are interrupted by a wave interruption 723. Indeed, the first partial corrugations 722 are interrupted when said first partial corrugation 722 crosses a corrugated metal connecting plate 71A. Thus, the wave interruption 723 is located at a distance from the radial corrugation 77 of said angular sector 25 or from a neighboring angular sector. In addition, the wave interruption 723 is located between two adjacent second corrugations 73.

[0091] By stopping the first partial corrugations 722 at a corrugated metal connecting plate 71A, it is thus possible to maintain a minimum distance between the radial corrugation 75 and said first partial corrugation 722 while limiting the maximum wave pitch between the radial corrugation 77 and the first corrugation 72 located closest to the radial corrugation 77.

[0092] There figure 7 represents more particularly one of the portions of crown 75 of the angular sector 25 illustrated in figure 6 . This figure illustrates in particular the particular assembly of the metal plates 71 with the connecting metal plates 71A. In addition, on this crown portion 75, one of the first partial undulations 722 crosses one of the connecting metal plates 71A and thus has a wave interruption 723.

[0093] In reference to the figure 8, a cutaway view of an LNG carrier ship 100 shows a sealed and thermally insulating tank 112 of generally prismatic shape mounted in the double hull 102 of the ship 100. The wall of the tank comprises a primary sealed membrane intended to be in contact with the LNG contained in the tank, a secondary sealed membrane arranged between the primary sealed membrane and the double hull 102 of the ship 100, and two thermally insulating barriers arranged respectively between the primary sealed membrane and the secondary sealed membrane and between the secondary sealed membrane and the double hull 102.

[0094] In a manner known per se, loading / unloading pipelines 103 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 112.

[0095] There figure 8represents an example of a maritime terminal comprising a loading and unloading station 105, an underwater pipeline 106 and a land storage facility 1. The loading and unloading station 105 is a fixed offshore installation comprising a mobile arm 104 and a tower 108 which supports the mobile arm 104. The mobile arm 104 carries a bundle of insulated flexible pipes 109 which can be connected to the loading / unloading pipelines 103. The orientable mobile arm 104 adapts to all sizes of LNG carriers. A connecting pipe, not shown, extends inside the tower 108. The loading and unloading station 105 allows the loading and unloading of the LNG carrier 100 from or to the land-based storage facility 1. The latter comprises liquefied gas storage tanks 20 and connecting pipes 111 connected by the underwater pipe 106 to the loading or unloading station 105.The subsea pipeline 106 allows the transfer of liquefied gas between the loading or unloading station 105 and the land-based storage facility 1 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 loading and unloading operations.

[0096] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 100 and / or pumps equipping the land-based storage facility 1 and / or pumps equipping the loading and unloading station 105 are used.

[0097] 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 technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0098] The use of the verb "comprise", "comprise" or "include" and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

[0099] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

1. Storage installation (1) for liquefied gas comprising: a supporting structure (10) having an internal space delimited by a bottom supporting wall (11) and a vertical supporting wall (12), a contour of said bottom supporting wall (11) having the shape of a regular polygon with N sides, N being an integer greater than or equal to 4, said vertical supporting wall (12) being composed of N vertical supporting faces (14) and forming a polygonal cylindrical surface having said regular polygon as a directrix, where each of the N sides of the polygon corresponds to an intersection of the bottom supporting wall (11) with one of said vertical supporting faces (14); and a sealed tank (20) installed in the internal space of the supporting structure (10), the sealed tank (20) comprising a bottom wall (21) arranged on the bottom supporting wall (11) and a vertical wall (22) arranged on the vertical supporting wall (12),said vertical wall (22) being composed of N vertical sections (24), each vertical section of the vertical wall (22) being fixed to one of the N vertical load-bearing sections (14), said bottom wall (21) comprising a plurality of angular sectors which are images of each other by a rotation of a predetermined angle around a vertical axis (Z), the predetermined angle being equal to k.360° / N, where k is a positive integer less than or equal to half of N, each angular sector (25) of the bottom wall (21) being connected to at least k of the N vertical sections (24) of the vertical wall (22), the sealed tank (20) comprising a corrugated sealed membrane (70, 170) intended to be in contact with a liquefied gas, in which the corrugated sealed membrane (70, 170) of each angular sector (25) of the bottom wall (21) has first corrugations (72) oriented along a sector axis (X),the sector axis (X) being perpendicular to a first vertical section connected to said angular sector (25), the first corrugations (72) being spaced two by two with a regular corrugation pitch, in which the corrugated waterproof membrane (70, 170) of each angular sector (25) of the bottom wall (21) comprises a plurality of metal plates (71) welded together in a sealed manner, the metal plates (71) being arranged to form crown portions (75) juxtaposed successively along the sector axis (X), each crown portion (75) being made up of a set of whole metal plates and in which the first corrugations (72) present on the crown portions (75) are in a total number per crown portion (75) which increases in the direction of the first vertical section, said total number per crown portion (75) being increased only every M successive crown portions (75), with M a natural integer greater than or equal to 2., 2. Storage installation (1) according to claim 1, in which the crown portions (75) have an inner edge and an outer edge perpendicular to the sector axis (X) and each a width extending along the sector axis (X) between the inner edge and the outer edge of the crown portion (75), said width being equal in several of said crown portions (75).

3. Storage facility (1) according to claim 2, wherein the width of the crown portion (75) located near a center of the bottom wall (21) and / or the width of the crown portion (75) located near the vertical wall (22) is different from the width of the other crown portions (75), preferably the other crown portions (75) being of identical width to each other.

4. Storage installation (1) according to one of claims 1 to 3, in which the regular wave pitch is greater than or equal to 400 mm, preferably greater than or equal to 800 mm, preferably between 800 and 1200 mm, for example equal to 1000 mm.

5. Storage installation (1) according to one of claims 1 to 4, wherein each crown portion (75) of an angular sector (25) comprises at least one corrugated metal connecting plate (71A) located on a lateral edge of the crown portion (75), the corrugated metal connecting plates (71A) being configured to connect said crown portion (75) with a crown portion (75) of an adjacent angular sector (25), the corrugated metal connecting plates (71A) of the crown portions (75) being aligned with each other in a radial direction, the radial direction being inclined relative to the sector axis (X), preferably by an angle equal to half the predetermined angle.

6. Storage installation (1) according to claim 5, in which the waterproof membrane of the angular sector (25) of the bottom wall (21) comprises a radial corrugation (77) located close to an edge of the angular sector (25), the radial corrugation (77) extending in the radial direction.

7. Storage installation (1) according to claim 6, wherein the first corrugations (72) of the angular sector (25) comprise first whole corrugations (721) extending from a junction (28) between the bottom wall (21) and the vertical wall (22) to a central crown portion near a center of the bottom wall (21), and first partial corrugations (722) which are interrupted by a wave interruption (723) when said first partial corrugation crosses one of the corrugated metal connecting plates (71A), the wave interruption (723) being located at a distance from the radial corrugation (77).

8. Storage installation (1) according to claim 6 or claim 7, in which the radial corrugation (77) of the angular sector (25) is produced on the corrugated metal connecting plates (71A).

9. Storage installation (1) according to one of claims 5 to 8, in which the corrugated metal connecting plate (71A) of a crown portion (75) of rank A is identical to the corrugated metal connecting plate (71A) of a crown portion (75) of rank A+B, where the rank is defined as being a natural whole number incremented moving away along the sector axis (X) towards the vertical wall (22), A being a natural whole number greater than or equal to 1 and B being a natural whole number greater than or equal to 2.

10. Storage installation (1) according to one of claims 1 to 9, in which the waterproof membrane of an angular sector (25) of the bottom wall (21) comprises second corrugations (73) spaced from each other and extending at least partially perpendicular to the first corrugations (72).

11. Storage facility (1) according to claims 7 and 10 taken in combination, wherein the wave interruption (723) of the first partial undulations (722) is located between two adjacent second undulations (73).

12. Storage facility (1) according to one of claims 1 to 11, wherein the storage facility (1) is a land-based storage facility.

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