Storage facility for liquefied gas

Abstract

The invention relates to a storage facility (1) for liquefied gas, comprising a supporting structure (2) and a sealed and thermally insulating tank (71), the tank (71) comprising at least one bottom wall (3), wherein the bottom wall (3) comprises a sump structure (9) comprising a container (11) having a side wall (15), the container (11) being arranged through the thickness of the bottom wall (3) and being located at least partially in a well (8) formed in the supporting structure (2), wherein the storage facility (1) comprises at least one base (19) connected to the supporting structure (2) and oriented along a first axis (X), the sump structure (9) comprising, for the at least one base (19), a guide device (18) in contact with the base (19) and having a degree of freedom in rotation about a second axis (Y) perpendicular to the first axis (X) and a degree of freedom in rotation about a third axis (Z) perpendicular to the first axis (X) and perpendicular to the second axis (Y).

Description

Description Title of the invention: Liquefied Gas Storage Facility technical field

[0001] The invention relates to the field of leak-proof and thermally insulated membrane tanks. In particular, the invention relates to the field of leak-proof and thermally insulated tanks for the storage and / or transport of liquefied gases at low temperatures, such as tanks for transporting Liquefied Petroleum Gas (LPG) at temperatures ranging, for example, from -50°C to 0°C, or for transporting Liquefied Natural Gas (LNG) at approximately -162°C at atmospheric pressure. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank can be used for transporting liquefied gas or for receiving liquefied gas to serve as fuel for the propulsion of the floating structure. Technological background

[0002] It is known from liquefied gas storage facilities, for example, in document W02020016509. Such a storage facility comprises a load-bearing structure and a sealed, thermally insulated tank located inside and attached to the load-bearing structure. The sealed, thermally insulated tank has a multilayer structure comprising, in one thickness direction, a sealing membrane and a thermally insulating barrier arranged between the sealing membrane and the load-bearing structure.

[0003] Such a storage installation includes a sump structure on the bottom wall of the tank, locally interrupting the sealing membrane. The sump structure comprises a container that extends through the bottom wall of the tank. The sump structure is positioned within a shaft in the supporting structure so that the liquid in the container is at the lowest level of the tank. By placing a pump inside such a container, it is possible to optimize the usable cargo volume that can be loaded into and discharged from the tank.

[0004] During the loading of the tank with liquefied gas such as LNG, the tank components in direct contact with the fluid, such as the sump structure, are subjected to significant temperature variations, resulting in thermal contraction. Therefore, in W02020016509, the sump structure is designed to be fixed to the supporting structure using a fastening device that allows for the contraction and expansion of the sump structure container, thus minimizing stress on the fastening device.

[0005] While such a system is satisfactory for limiting the mechanical stresses related to the thermal contraction of the sump structure, it has the disadvantage of being complex and requiring a lot of assembly time when attaching the sump structure to the supporting structure.

[0006] Indeed, during assembly, it is necessary to check the inclination and centering of the sump structure while ensuring that the support all around the structure is sufficient. Furthermore, any unevenness in the supporting structure must be taken into account during these checks. Summary of the invention

[0007] One idea behind the invention is to simplify the assembly of the sump structure in a storage facility while allowing for thermal contraction / expansion of the sump structure.

[0008] According to one embodiment, the invention provides a liquefied gas storage installation comprising a load-bearing structure and a sealed and thermally insulated tank, the tank having at least one bottom wall fixed to the load-bearing structure, wherein the bottom wall has a multilayer structure in one thickness direction including at least one sealed membrane and at least one thermally insulating barrier disposed between the sealed membrane and the load-bearing structure, wherein the bottom wall has a sump structure locally interrupting the sealed membrane of the bottom wall, the sump structure having a container having a side wall, the container being arranged through the thickness of the bottom wall and being located at least partially in a well formed in the load-bearing structure, the well extending outwards from the tank along a well axis,in which the storage installation comprises at least one base connected to the supporting structure and oriented along a first axis parallel to the well axis, the sump structure comprising, for said at least one base, a device, of guidance in contact with said base and having, in an installation configuration, a degree of freedom in rotation around a second axis perpendicular to the first axis and a degree of freedom in rotation around a third axis perpendicular to the first axis and perpendicular to the second axis, allowing the sump structure to be guided relative to the supporting structure.

[0009] Thanks to these features, the guide system simplifies the assembly of the sump structure. Indeed, the guide system's degrees of freedom allow for easier adjustment of the sump structure's inclination during assembly. The guide system's contact with the base compensates for imperfections in the supporting structure.

[0010] Depending on the embodiment, such an installation may include one or more of the following characteristics.

[0011] According to one embodiment, the load-bearing structure comprises a flat load-bearing wall pierced with an opening forming an entrance to the well, at least one base being fixed to the flat load-bearing wall around the opening forming the entrance to the well.

[0012] According to one embodiment, the waterproof membrane is hermetically bonded to the container all around the container.

[0013] According to one embodiment, said at least one base comprises a base fixed to the supporting structure and a contact element having a convex spherical surface in cooperation with the guiding device.

[0014] Thanks to these characteristics, the mechanical link between the contact element and the guiding device can be likened to a ball joint with a finger.

[0015] According to one embodiment, the contact element has an opening in its center along the first axis to allow a mechanical link with the base located under the contact element.

[0016] According to one embodiment, the base has a main body fixed to the supporting structure and carrying the contact element along the first axis, and at least one protrusion fixed to the supporting structure and extending outwards from the sump structure.

[0017] Thus, the presence of a protrusion increases the weld surface area of ​​the bases to the supporting structure, which improves stability; moreover, the orientation of the protrusion allows the weld beads of the sump structure and the welds of the protrusion work in the same direction, solidifying the storage installation.

[0018] According to one embodiment, said at least one base comprises a retaining plate positioned between the base and the contact element.

[0019] In one embodiment, the retaining plate comprises a circular portion mirroring the shape of the main body of the base, and two ends extending beyond the main body. Advantageously, the two ends have holes allowing a connection between the retaining plate and the sump structure, in particular a link to the support plate of the guide device.

[0020] According to one embodiment, the base includes a means for adjusting the height of said at least one base so as to ensure cooperation between the guidance device and said at least one base.

[0021] Thus, the means of adjusting the height of the base allows, during the assembly of the sump structure, for easier adaptation of the height of the base, and consequently of the inclination of the sump structure.

[0022] In one embodiment, the means for adjusting the height of the base is a U-shaped adjustment plate. Advantageously, the adjustment plate can be inserted between the contact element and the retaining plate. Alternatively, the adjustment plate can be inserted between the retaining plate and the base.

[0023] Thus, the U shape allows the insertion of the means for adjusting the height of the base after the attachment between the base and the guiding device.

[0024] According to one embodiment, the contact element or retaining plate has a notch on one end allowing the contact element or retaining plate to be gripped.

[0025] Thus, it is possible to lift the contact element or retaining plate, and then insert the adjustment plate.

[0026] In one embodiment, the means for adjusting the height of the base includes adjusting screws (for example, height adjustment screws) housed in holes located at the ends of the retaining plate. Advantageously, the adjusting screws are oriented towards the load-bearing structure, thus allowing the retaining plate and the contact element to be lifted when the adjusting screws are tightened. Alternatively, the adjusting screws are oriented towards the guide device; the adjusting screws push the guide device when the adjusting screws are screwed in.

[0027] In one embodiment, the retaining plate also serves as the adjustment means. Advantageously, the retaining plate is threaded inside the base, such that screwing the retaining plate reduces the height of the retaining plate and the contact element.

[0028] According to one embodiment, the guiding device comprises a support plate having an outer face, a part of the outer face having a concave spherical surface and cooperating with the base.

[0029] According to one embodiment, the support plate has an inner face comprising a means of attachment to the sump structure.

[0030] According to one embodiment, the side wall of the sump structure includes for the guiding device a hooking element arranged opposite the inner face of the support plate and in cooperation with the hooking means of the support plate.

[0031] According to one embodiment, the means of attaching the support plate is at least one centering pin.

[0032] According to one embodiment, the side wall attachment element includes a receiving hole for each centering pin of the support plate and at least one centering pin is configured to fit inside the corresponding receiving hole.

[0033] According to one embodiment, the storage installation further includes an anti-lifting element fixing the support plate to said at least one base so as to ensure permanent contact between said at least one base and the guiding device.

[0034] Thus, the anti-uplift element makes it possible to limit any possible uplift of the sump structure in a direction parallel to the well axis in the event of pressure differences between the inside of the tank and the thermally insulating barrier.

[0035] According to one embodiment, the container and the well are cylindrical in shape with a circular cross-section, and the storage installation comprises at least two bases, such as the at least two bases are separated by an angle 3607N, N being an integer corresponding to the number of bases, preferably N is equal to 4.

[0036] Therefore, a greater number of bases, and consequently more guide devices, facilitates the assembly of the sump structure by making it easier to establish contact between the bases and the guide devices. Furthermore, choosing four bases allows them to be positioned along the main axes of the tank.

[0037] According to one embodiment, the storage installation comprises four bases distributed regularly around the well, the watertight membrane comprising a first series of parallel corrugations extending in a first direction and a second series of parallel corrugations extending in a second direction, two of the four bases being aligned with the center of the container in the first direction and two other of the four bases being aligned with the center of the container in the second direction.

[0038] In one embodiment, the bases and guide devices are metallic, preferably stainless steel. In a particular embodiment, the bases and guide devices are cast iron.

[0039] According to one embodiment, an inner surface of the base contact element and the outer surface of the guiding device have an arithmetic mean roughness (R a) between 0.2 and 3.2 pm, preferably between 0.2 and 1.6 pm.

[0040] According to one embodiment, the base has a coating made of a material with a coefficient of friction less than 0.2, preferably between 0.05 and 0.2. To facilitate sliding, it is possible to add a polytetrafluoroethylene (PTFE) or high-density polyethylene (HDPE) type coating to the base, or to lubricate the base.

[0041] According to one embodiment, the well axis is a well axis of revolution and the sump structure has a sump structure axis of revolution, the well axis of revolution and the sump structure axis of revolution being parallel and spaced from each other by a distance of between 0 and 30 mm.

[0042] An installation according to the invention may be a land-based storage facility, for example for storing LNG, or a floating storage facility, coastal or deep water, in particular for an LNG carrier, a floating storage and regasification unit (FSRU), a floating production and remote storage unit (FPSO) and others. Such an installation can also serve as a fuel tank in any type of ship.

[0043] According to one embodiment, the invention also provides a method for assembling a sump structure of a liquefied gas storage facility, the storage facility comprising a load-bearing structure and a sealed and thermally insulated tank, in which the method comprises the following steps: - provide the supporting structure including a well, the well extending outwards from the tank along a well axis, - fix at least one base to the supporting structure so that at least one base is arranged around the well and oriented along a first axis parallel to the axis of the well, - provide a sump structure comprising a container having a side wall, the sump structure comprising for said at least one base, a guiding device having, in an installation configuration, one degree of freedom in rotation about a second axis perpendicular to the first axis and one degree of freedom in rotation about a third axis perpendicular to the first axis and perpendicular to the second axis, - lower the sump structure so as to place the guiding device in contact with said at least one base and so as to position the container at least partially in the well, - Adjust the centering and inclination of the sump structure using the guiding device, - fix the guiding device to said at least one base.

[0044] According to one embodiment, the invention also provides a method for assembling a sump structure of a liquefied gas storage facility, the storage facility comprising a load-bearing structure and a sealed and thermally insulated tank, in which the method comprises the following steps: - provide the supporting structure including a well, the well extending outwards from the tank along a well axis, - fix at least one base to the supporting structure so that at least one base is arranged around the well and oriented along a first axis parallel to the axis of the well, - to bring into contact, for said at least one base, a guiding device having, in an installation configuration, one degree of freedom in rotation around a second axis perpendicular to the first axis and one degree of freedom in rotation around a third axis perpendicular to the first axis and perpendicular to the second axis, - provide a sump structure comprising a container with a side wall, - lower the sump structure so that the side wall hooks onto the guiding device and so that the container is at least partially positioned in the well, - Adjust the centering and inclination of the sump structure using the guiding device, - fix the guiding device to said at least one base.

[0045] According to one embodiment, the invention also relates to a ship for the transport of a liquefied gas, the ship comprises a double hull and a aforementioned storage installation disposed in the double hull.

[0046] According to one embodiment, the invention also provides a transfer system for a liquefied gas, 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 facility, and a pump to drive a flow of liquefied gas through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

[0047] According to one embodiment, the invention also provides a method for loading or unloading a ship, in which a liquefied gas is conveyed through insulated pipelines from or to a floating or land-based storage facility to or from the tank of the aforementioned ship. Brief description of the figures

[0048] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation, with reference to the accompanying drawings.

[0049] Figure 1 represents a cross-sectional view of the sump structure arranged in the shaft of the supporting structure of a storage facility according to the invention and according to one embodiment.

[0050] Figure 2 shows a cross-sectional view of a sump structure and in particular of its guidance device mounted on a base of the supporting structure.

[0051] Figure 3a shows in perspective the base constituting the first layer of the base of the load-bearing structure.

[0052] Figure 3b shows in perspective the retaining plate mounted on the base in one variant of the invention.

[0053] Figure 3c shows in perspective the U-shaped adjustment plate mounted on the retaining plate in one embodiment of the invention.

[0054] Figure 3d shows in perspective the contact element mounted on the retaining plate in one variant of the invention.

[0055] Figure 4 shows in perspective the external surface of the sump structure guidance device.

[0056] Figure 5a shows a perspective view of a first embodiment of the guidance device mounted on the base of the supporting structure.

[0057] Figure 5b shows a perspective view of a second embodiment of the guidance device mounted on the base of the supporting structure.

[0058] Figure 6a represents a perspective view of a sump structure and in particular of its guidance device mounted on a base of the supporting structure with an anti-uplift element according to one embodiment.

[0059] Figure 6b shows a perspective view of a sump structure and in particular of its guide device mounted on a base of the supporting structure with height adjustment screws according to one embodiment.

[0060] Figure 7 is a schematic cutaway representation of an LNG carrier comprising a storage facility and a loading / unloading terminal for this storage facility. Description of the implementation methods

[0061] The description below describes a storage installation 1 for the storage and / or transport of liquefied gas, comprising a load-bearing structure 2 and a sealed and thermally insulated tank 71. The sealed and thermally insulated tank 71 includes, in particular, a bottom wall 3, preferably generally flat, located at the bottom of the tank relative to the Earth's gravitational field. The overall geometry of the tank can be of various types. Polyhedral geometries are the most common. A cylindrical geometry is also possible.

[0062] The terms "inside" and "outside" are to be taken into consideration in relation to the center of tank 71.

[0063] The bottom wall 3 is mounted on a supporting structure 2, made, for example, of thick steel sheet such as the inner hull of a double-hulled ship 70. The bottom wall 3 has a multilayer structure comprising successively a secondary thermally insulating barrier 4 fixed to the supporting structure 2, a secondary airtight membrane 5 supported by the secondary thermally insulating barrier 4, a primary thermally insulating barrier 6 placed on the secondary airtight membrane 5, and a primary airtight membrane 7 supported by the primary thermally insulating barrier 6 and intended to be in contact with the liquefied gas contained in the tank 71. The multilayer structure is shown schematically in Figure 1. The primary airtight membrane 7 defines an internal space intended to receive the liquefied gas.As an example, such membrane tanks are described in particular in patent applications WO2019239048, WO14057221, FR2691520 and FR2877638.

[0064] The liquefied gas intended for storage in tank 71 may be, in particular, liquefied natural gas (LNG), that is, a gaseous mixture consisting mainly of methane and one or more other hydrocarbons. The liquefied gas may also be ethane or liquefied petroleum gas (LPG), that is, a mixture of hydrocarbons derived from petroleum refining, consisting primarily of propane and butane.

[0065] Figure 1 represents the sump structure 9 which includes a first container 10 in communication with the interior of the tank, and a second container 11 surrounding the lower part of the first container 10. The first container 10 is continuously and hermetically connected to the primary sealing membrane 7. Similarly, the second container 11 is continuously and hermetically connected to the secondary sealing membrane 5, which it thus completes hermetically.

[0066] Well 8 is intended to receive a sump structure 9 which will be described later.

[0067] More specifically, the first container 10 comprises a cylindrical side wall 12 whose axis is perpendicular to the load-bearing wall and which has a first fixing collar 13 located on an upper part of the cylindrical side wall 12 and essentially aligned with the primary waterproof membrane 7. A part The lower part of the cylindrical side wall 12 is engaged in the well 8 of the supporting structure 2. A lower wall 14 parallel to the supporting structure 2 closes the cylindrical side wall 12 at its lower part. The first fixing collar 13 is fixed to the edge of the upper part of the cylindrical side wall 12 and projects radially outwards from it all around the first container 10. Thus, the fluid contained in the first container 10 is located at the lowest level of the tank 71.

[0068] Similarly, the second container 11 has a cylindrical side wall 15 whose axis is perpendicular to the supporting wall and which has a second fixing collar 16 essentially aligned with the secondary sealing membrane 5 and a lower portion engaged in the well 8 below the lower wall 14 of the first container 10. A lower wall 17 parallel to the supporting wall closes the cylindrical side wall 15 of the second container 11 at its lower portion. The cylindrical side wall 15 of the second container 11 surrounds the cylindrical side wall 12 of the first container 10 at a distance from it. The second fixing collar 16 is fixed at the edge of the upper portion of the cylindrical side wall 15 and projects radially outward from it all around the second container 11.

[0069] Insulating elements 37, visible in figure 1, are arranged all around the first container 10 and the second container 11.

[0070] In operation, due to its position below the primary sealing membrane 7, the first container 10 receives by gravity any residual liquid in the tank, like a sump. The first container 10 has sufficient capacity to keep the suction head of a pump immersed in the liquid, thus maximizing the tank's operating efficiency.

[0071] To have good structural stability, the first container 10 and the second container 11 are made of a material more rigid than the waterproof membranes, for example with a metal sheet of the order of 6 to 20 mm thick.

[0072] As shown in particular in Figures 1 to 6, the sump structure 9 comprises at least one attachment element 27 welded to the side wall 15 of the second container 11. The attachment element 27 is connected to a guide device 18 by means of an attachment means 25 which allows the structure to rest on sump 9 on the supporting structure 2, when the guiding device 18 is in contact with the base 19.

[0073] In the described embodiment, the sump structure 9 comprises two containers 10, 1, 1 located one inside the other because, in the example, tank 71 is a double-membrane tank. However, the invention is also applicable to single-membrane tanks. In such a case, the side wall 15 of the single container has at least one attachment element 27 welded to the side wall 15 of the second container 11. The hooking element 27 is connected to a guide device 18 by means of a hooking means 25 allowing the sump structure 9 to rest on the supporting structure 2, when the guide device 18 is in contact with the base 19.

[0074] Other embodiments of a sump structure 9 are described for example in document WO2016 / 001 142.

[0075] According to one embodiment, the storage facility 1 comprises at least two bases 19, such that the at least two bases 19 are separated by an angle of 3607N, N being an integer corresponding to the number of bases 19, preferably N is equal to 4.

[0076] According to one embodiment, the storage facility 1 comprises four bases 19 distributed regularly around the well 8, the watertight membrane 7 comprising a first series of parallel undulations extending in a first direction and a second series of parallel undulations extending in a second direction, two of the four bases 19 being aligned with the center of the container 11 in the first direction and two other bases 19 being aligned with the center of the container 11 in the second direction.

[0077] Furthermore, in the case of a storage facility 1 installed on a ship 70, the first direction may advantageously be the longitudinal direction of the ship 70 while the second direction may be the transverse direction of the ship 70.

[0078] In the embodiment with four bases 19, these are fixed to the supporting structure 2 and are distributed regularly around the edge of the well 8. In other embodiments not shown, the number of bases 19 could be different, for example a single base 19 or two bases 19, or eight bases 19, or twelve bases 19, or even eighteen bases.

[0079] Advantageously, when the number of bases 19 increases, the size of the bases 19 can be reduced.

[0080] Advantageously, the number of bases 19 is suitable for the type of liquefied gas contained in tank 71.

[0081] In one embodiment, each base 19 comprises a base 20 fixed to the supporting structure 2 and a contact element 21 having a convex spherical surface in cooperation with the guiding device 18.

[0082] According to one embodiment, the base 20 has a main body 201 fixed to the supporting structure 2 and carrying the contact element 21 along the first axis X, and at least one protrusion 202 fixed to the supporting structure 2 and extending outwards from the sump structure 9, visible in Figure 2.

[0083] Advantageously, the main body 201 of the base 20 is cylindrical in shape.

[0084] Advantageously, the base 20 has a diameter between 40 and 60mm, preferably 50mm; the base has a height between 20 and 30mm, preferably 25mm.

[0085] Advantageously, the base 20 includes an opening in its center, intended to be positioned opposite the opening 30 of the contact element. The opening in the base 20 allows for an additional connection between the base 20 and the supporting structure 2. Advantageously, the opening in the base 20 allows for a connection between the elements arranged on the base 20 and the supporting structure 2.

[0086] The presence of at least one protrusion 202 increases the contact area between the base 19 and the supporting structure 2, thus increasing the weld area between the base 19 and the supporting structure 2.

[0087] Advantageously, at least one protuberance 202 is a polyhedron having four faces: a contact face welded to the main body 201 of the base 20; a load-bearing face welded to the load-bearing structure 2; and two lateral faces each joined to all the other faces previously mentioned; in this embodiment the polyhedron is a pyramid with a triangular base whose apex is in contact with the main body 201 of the base 20.

[0088] Advantageously, at least one protrusion 202 is a polyhedron with five faces. Among the five faces, there is a contact face welded to the main body 201 of the base 20; a load-bearing face welded to the load-bearing structure 2; a face interior; and two lateral faces each joined to all the other faces previously mentioned, the two lateral faces being opposite each other.

[0089] Advantageously, the inner face of at least one protrusion 202 has at least one surface, such that the set of at least one surface end to end connects the base 20 with the supporting structure 2.

[0090] For example, the inner face of at least one protrusion 202 comprises 3 surfaces, the example is visible in figures 2 to 6. The first surface is perpendicular to the contact face, one end is welded to the base 20, the opposite end joins one end of the second surface; the second surface has an angle of 45° and its opposite end joins one end of the third surface; the third surface is perpendicular to the supporting structure 2 and orthogonal to the first surface, the opposite end of the third surface is welded to the supporting structure 2.

[0091] Advantageously, the contact face of the protuberance 202 has a smaller height than the height of the main body 201, and preferably the contact face follows the shape, preferably the curvature, of the surface of the main body 201.

[0092] Advantageously, the contact element 21 is a hemisphere whose flat part is oriented towards the base 20 once the contact element 21 and the base 20 are assembled.

[0093] According to one embodiment, the contact element 21 has an opening 30 in its center along the first axis X to allow a mechanical link with the base 20 located below.

[0094] Advantageously, the mechanical link is a screw or an element welded inside the base 19.

[0095] In an alternative embodiment, each base 19 includes a retaining plate 26 for example positioned between the base 20 and the contact element 21.

[0096] Thus, it is possible to adjust the height of one side of the sump structure 9 according to the flatness defects.

[0097] According to a particular embodiment as illustrated for example in Figure 3b and 3d, the retaining plate 26 comprises a circular part following the shape of the main body 201 of the base 20, and two ends 261 protruding from the main body 20. Advantageously, both ends 261 have holes 262 allowing a connection between the retaining plate 26 and the structure of the sump 9, in particular a mechanical link with the support plate 22 of the guide device 18.

[0098] According to one embodiment, at least one base 19 includes a means for adjusting the height of said base so as to ensure cooperation between the guidance device 18 and the base 19.

[0099] In an embodiment illustrated for example in Figure 3c, the means for adjusting the height of the base 19 is a U-shaped adjustment plate 29. Advantageously, the adjustment plate 29 is inserted between the contact element 21 and the retaining plate 26. Advantageously, the adjustment plate 29 is inserted between the retaining plate 26 and the base 20.

[0100] According to an embodiment not shown, the contact element 21 or the retaining plate 26 has a notch on one end allowing the contact element 21 or the retaining plate 26 to be gripped.

[0101] Advantageously, the notch allows the contact element 21 or the retaining plate 26 to be lifted so as to insert the height adjustment means of the base 19 below the lifted element.

[0102] In another embodiment, the base adjustment means 19 includes height adjustment screws 28, the height adjustment screws 28 of the base 19 being housed in the holes 262 of the ends 261 of the retaining plate 26.

[0103] In one embodiment, the adjusting screws 28 are oriented towards the supporting structure 2, thus allowing the retaining plate 26 and the contact element 21 to be lifted when the adjusting screws 28 are screwed in.

[0104] Advantageously, the operator can screw or unscrew the adjustment screws 28 to adjust the height of the base 19 to position the sump structure 9.

[0105] In an alternative embodiment, the adjusting screws 28 are oriented towards the guide device 18.

[0106] Advantageously, the operator can screw or unscrew the adjustment screws 28 to adjust the height of the base 19 during assembly to position the sump structure 9.

[0107] According to another embodiment, the retaining plate 26 is also the means of adjustment. Advantageously, in such a case, the retaining plate 26 is threaded. inside the base 20, such that screwing the retaining plate 26 reduces its height and consequently the height of the contact element 21.

[0108] The sump structure 9 and its guiding device 18 will be described in more detail with the help of figures 1 to 6 which illustrate the invention at different stages of the assembly of the sump structure 9.

[0109] The sump structure 9 includes, for each base 19, a guide device 18 in contact with said base 19 and having, in a positioning configuration, a degree of freedom in rotation about a second axis Y perpendicular to the first axis X and a degree of freedom in rotation about a third axis Z perpendicular to the first axis X and perpendicular to the second axis Y, allowing the sump structure 9 to be guided relative to the supporting structure 2.

[0110] According to one embodiment, each guiding device 18 comprises a support plate 22 having an outer face 23, a part of the outer face 23 having a concave spherical surface and cooperating with the base 19, visible in Figure 4.

[0111] Advantageously, the concave spherical surface is such that it conforms to the convex spherical surface of the contact element 21 of the base 19 when the outer face 23 is in contact with the contact element 21.

[0112] Advantageously, the concave spherical surface of the support plate 22 must be large enough to distribute the pressure exerted by the sump structure 9 and by the cargo. Advantageously, the concave spherical surface is small enough not to impede the rotational degrees of freedom.

[0113] Preferably, the outer face of the support plate 22 has a larger surface area than the inner surface of the contact element 21.

[0114] According to one embodiment, the support plate 22 has an inner face 24 comprising a means of attachment 25 to the sump structure 9.

[0115] According to one embodiment, the side wall 15 of the sump structure 9 comprises for each guide device 18 a hooking element 27 arranged opposite the inner face 24 of the support plate 22 and cooperating with the hooking means 25 of the support plate 22.

[0116] According to one embodiment, the attachment means 25 of the support plate 22 is at least one centering pin 251.

[0117] According to one embodiment, each hooking element 27 of the side wall 15 includes a receiving hole 271 for each centering pin 251 of the support plate 22 and at least one centering pin 251 is configured to fit inside the corresponding receiving hole 271.

[0118] For example, in figure 2, a hooking element 27 has two corresponding receiving holes 271 and accommodates two centering pins 251 of the guiding device 18.

[0119] The fixing of at least one centering pin can be achieved using a washer / nut assembly 36 as shown in Figure 6a and Figure 6b.

[0120] For example, in Figures 6a and 6b, the attachment element 27 consists of a plate attached to the side wall 15 of the sump structure 9 by a contact face and by two symmetrical and similar polyhedra, leaving a surface available on an inner face of the plate for fixing the centering pins 251 by means of a washer / nut system 36. The two polyhedra are fixed to the inner face of the plate and also to the side wall 15. The face of the two polyhedra welded to the side wall has a chamfer on the lower part of the polyhedra, the chamfer connecting the side wall 15 to the inner face of the plate. The chamfer allows for consideration of the thermal contractions and expansions of the materials.

[0121] According to one embodiment, the storage installation 1 further includes an anti-lifting element 35 fixing the support plate 22 to the base 19 so as to ensure permanent contact between the base 19 and the guiding device 18.

[0122] Advantageously and as shown in Figure 6a, the retaining plate 26 comprises at least one end 261 and the support plate 22 comprises at least one connection orifice 221 vis-à-vis at least one end 261, an anti-lifting element 35 is fixed to the support plate 22 through at least one connection orifice 221 and has a volume portion under at least one end 261 such that the guide device 18 remains in contact with the base 19.

[0123] Figure 3a represents a first step in the assembly of the sump structure 9 to the supporting structure 2, common to a first variant and a second variant of assembly, this first step is the positioning and welding of the base 20 on the supporting structure 2 not shown.

[0124] Figure 3b represents a second optional step in mounting the sump structure 9 to the supporting structure 2, common to the first variant and the second mounting variant, this second step is the placement of the retaining plate 26 on the base 20.

[0125] Figure 3d represents a third assembly step of the sump structure 9 to the supporting structure 2, common to the first and second assembly variants, this third step is the placement of the contact element 21 on the adjustment plate 29 if the optional adjustment step has been carried out; otherwise the contact element 21 is placed on the retaining plate 26, if the second step has been carried out; otherwise the contact element is placed on the base 20.

[0126] Optionally, in an assembly step not shown, the contact element 21 is mechanically linked to the base 19 by means of an element inserted into the opening 30 of the contact element 21.

[0127] Figure 5a represents a fourth mounting step of the sump structure 9 to the supporting structure 2 in the first mounting variant with a first embodiment of the support plate 22 of the guide device 18. This first embodiment of the support plate 22 includes a hooking means 25 comprising a centering pin 251 located at the center of the inner face 24 of the support plate 22.

[0128] Figure 5b represents a fourth mounting step of the sump structure 9 to the supporting structure 2 in the first mounting variant with a second embodiment of the support plate 22 of the guide device 18. This second embodiment of the support plate 22 includes a hooking means 25 comprising two centering pins 251 located symmetrically with respect to the center of the inner face 24 of the support plate 22. The inner face 24 of the support plate 22 has a longitudinal dimension larger than a transverse dimension, the two centering pins 251 are arranged in the middle of the longitudinal dimension.

[0129] Optionally, with this second embodiment of the support plate 22, there is also an orifice in the center of the inner face 24, allowing in an assembly step not shown, to mechanically link the contact element 21 to the base 19 by means of an element inserted in the orifice and in the opening 30 of the contact element 21.

[0130] In this first mounting variant, each guide device 18 is pre-assembled on the base 19 before being put in place with the hooking element 27 of the sump structure 9.

[0131] In a fifth step of mounting the sump structure 9 to the supporting structure 2 not shown, the sump structure 9 is lifted and placed vertically above the shaft 8, for example using a winch.

[0132] Furthermore, after being lowered, the hooking element(s) 27 of the sump structure 9 are brought into contact with the pre-assembled guide device(s) 18.

[0133] By moving the guide device(s) 18 on the inner surface of the contact element(s) 21 of the bases 19 arranged all around the well 8, it is possible to adjust the inclination of the sump structure 9, thanks to the rotational degrees of freedom of the guide devices 18. Similarly, by moving the guide device(s) 18 on the inner surface of the contact element(s) 21 of the bases 19 arranged all around the well 8, it is possible to adjust the centering of the sump structure 9 with respect to the well 8.

[0134] During the centering of the sump structure 9, it is possible to center it using markings made on the supporting structure 2 that represent the future locations of the insulating panels and / or the corrugations of the corrugated waterproofing membranes. This centering with the markings may result in an offset 38 between the axis of revolution 39 of the well 8 and the axis of revolution 40 of the sump structure 9, as shown in Figure 1. Nevertheless, despite this potential offset, the support of the sump structure 9 on the supporting structure 2 is still ensured by the interaction between the base(s) 19 and the guide(s) 18.

[0135] In this first variant of mounting the sump structure 9 to the supporting structure 2, a connection step is required between the guide device(s) 18 and the sump structure 9. This step is carried out by inserting the centering pin(s) 251 of the attachment means 25 of the support plate 22, in cooperation with the corresponding receiving holes 271 of the attachment element 27 of the sump structure 9. Optionally, the centering pin(s) 251 are mechanically fixed by a washer / nut system 36 onto the attachment element(s) 27, as shown in Figures 6a and 6b.

[0136] In the second mounting variant, a fourth mounting step of the sump structure 9 to the supporting structure 2, not shown, consists of integrating the support plate 22 of the guide device 18 into the hooking element 27 of the sump structure 9. This fourth step enables the connection between the guide device(s) 18 and the sump structure 9 by means of the insertion of the centering pin(s) 251 of the hooking means 25 of the support plate 22, in cooperation with the corresponding receiving holes 271 of the hooking element 27 of the sump structure 9. Optionally, the centering pin(s) 251 are mechanically fixed by a washer / nut system 36 on the hooking element(s) 27, visible in Figures 6a and 6b.

[0137] Advantageously, the support plate 22 can be in a first configuration, with a single centering pin 251 or be in a second configuration with two centering pins 251 located symmetrically with respect to the center of the inner face 24 of the support plate 22. The inner face 24 of the support plate 22 comprises a longitudinal dimension larger than a transverse dimension, the two centering pins 251 are arranged in the middle of the longitudinal dimension.

[0138] In this second mounting variant, each guide device 18 is assembled to the sump structure 9.

[0139] In a fifth step of mounting the sump structure 9 to the supporting structure 2, not shown, the sump structure 9 is lifted and placed vertically above the shaft 8, for example using a winch.

[0140] Furthermore, after being lowered, the outer face 23 of the support plate(s) 22 are brought into contact with the base(s) 19 of the supporting structure 2.

[0141] By moving the guide device(s) 18 on the inner surface of the contact element(s) 21 of the bases 19 arranged all around the well 8, it is possible to adjust the inclination of the sump structure 9, thanks to the rotational degrees of freedom of the guide devices 18. Similarly, by moving the guide device(s) 18 on the inner surface of the contact element(s) 21 of the bases 19 arranged all around the well 8, it is possible to adjust the centering of the sump structure 9 with respect to the well 8.

[0142] When centering the sump structure 9, it is possible to center the sump structure 9 with markings made on the supporting structure 2 and representing the future locations of the insulating panels and / or the corrugations of the corrugated waterproofing membranes. This centering with the markings may result in an offset 38 between the axis of revolution 39 of the well 8 and the axis of revolution 40 of the sump structure 9, as seen in Figure 1. Nevertheless, despite a possible offset, the support of the sump structure 9 on the load-bearing structure 2 is still ensured by the cooperation between the base(s) 19 and the guiding device(s) 18.

[0143] In a sixth step, not shown, of mounting the sump structure 9 to the supporting structure 2, common to the first variant and the second variant of mounting, once the sump structure 9 is installed in the well 8 with a centering and inclination set by an operator, the guide device(s) 18 are fixed to the corresponding bases.

[0144] Figure 3c illustrates an optional height adjustment step in the mounting of the sump structure 9 to the supporting structure 2, common to both the first and second mounting variants. In this embodiment, this adjustment step involves positioning the height adjustment plate 29 on the retaining plate 26. Advantageously, this adjustment step can be performed after any subsequent step.

[0145] In another embodiment of the means for adjusting the height of the base 19, the retaining plate 26 is also the means for adjusting the height of the base 19. The retaining plate 26 includes a threaded part inside the base 20. In the optional step of adjusting the height of the base 19 in the mounting of the sump structure 9 to the supporting structure 2, common to the first variant and the second variant of mounting, the retaining plate 26 is screwed or unscrewed to adjust the height of the contact element 21.

[0146] In another embodiment of the means for adjusting the height of the base 19, said adjustment means includes adjustment screws 28. The adjustment screws 28 are housed in the holes 262 present on the ends 261 of the retaining plate 26.

[0147] In the first configuration, visible in Figure 6b, the adjusting screws are oriented towards the guide device 18. In the optional height adjustment step during the mounting of the sump structure 9 to the supporting structure 2, common to both the first and second mounting variants, the screws of Adjustment 28 are screwed or unscrewed to adjust the height of the support plate 22.

[0148] For example, in Figure 6b, the adjusting screws 28 have two main screws, each passing through a hole 262 in the retaining plate. These two main screws are each connected to an adjusting board with two additional holes and cooperating with two secondary screws. The two secondary screws on the adjusting board allow the height to be adjusted on a targeted part of the guide device 18. One secondary screw allows the height to be adjusted on the part of the guide device 18 closest to the side wall 15, while the second secondary screw allows the height to be adjusted on the part of the guide device 18 furthest from the side wall 15.

[0149] In a second configuration, not shown, the adjusting screws are oriented towards the guide device 18. In the optional height adjustment step in the assembly of the sump structure 9 to the supporting structure 2, common to the first and second assembly variants, the adjusting screws 28 are screwed or unscrewed to adjust the height of the retaining plate 26.

[0150] Figure 6a shows an optional step in the assembly of the sump structure 9 to the supporting structure 2, common to both the first and second assembly variants. This step adds at least one anti-uplift element 35 that secures the support plate 22 to the base 19 in such a way as to ensure permanent contact between the base 19 and the guide device 18.

[0151] Advantageously, the retaining plate 26 includes at least one end 261 and the support plate 22 includes at least one connection orifice 221 vis-à-vis at least one end 261, in this optional step, the anti-lift element 35 is fixed to the support plate 22 through at least one connection orifice 221, such that a volume portion of the anti-lift element 35 is under at least one end 261.

[0152] So that the contact element 21 is gripped between the retaining plate 26 and the support plate 22. Thus, the translation in the direction parallel to the well axis 39 of the sump structure 9 is limited.

[0153] The anti-lift elements 35 are not tightened on the ends 261 of the retaining plate 26 or with relatively low tightening, so as not to prevent the sump structure 9 from contracting / expanding thermally.

[0154] The contact elements 21 are tightly clamped to the base 20.

[0155] Following this step, insulating elements are placed all around the sump structure 9 and then the secondary thermally insulating barrier 4 is assembled around the sump structure 9. The secondary waterproof membrane 5, the primary thermally insulating barrier 6 and the primary waterproof membrane 7 are then successively assembled.

[0156] With reference to Figure 7, a cutaway view of a LNG carrier 70 shows a sealed and thermally insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the ship 70. The wall of the tank 71 comprises the primary sealed membrane 7 intended to be in contact with the LNG contained in the tank, the secondary sealed membrane 5 arranged between the primary sealed membrane 7 and the double hull 72 of the ship 70, and the two thermally insulating barriers arranged respectively between the primary sealed membrane 7 and the secondary sealed membrane 5 and between the secondary sealed membrane 5 and the double hull 72.

[0157] As is known per se, loading / unloading pipelines 73 arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a marine or port terminal to transfer a cargo of LNG to or from the tank 71.

[0158] Figure 7 shows an example of a marine terminal comprising a loading and unloading berth 75, a subsea pipeline 76, and an onshore installation 77. The loading and unloading berth 75 is a fixed offshore installation comprising a movable arm 74 and a tower 78 that supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 that can be connected to the loading / unloading pipelines 73. The steerable movable arm 74 adapts to all LNG carrier sizes. An unshown connecting pipeline extends inside tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore facility 77. This facility includes liquefied gas storage tanks 80 and connecting pipelines 81 linked by the subsea pipeline 76 to the loading or unloading station 75.The subsea pipeline 76 allows the transfer of liquefied gas between the loading or unloading station 75 and the onshore installation 77 over a long distance, for example 5 km, which allows the ship to be kept. LNG carrier 70 at a great distance from the coast during loading and unloading operations.

[0159] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the land installation 77 and / or pumps equipping the loading and unloading station 75 are used.

[0160] Although the invention has been described in connection with several particular embodiments, it is clearly evident that it is by no means limited to them 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.

[0161] The use of the verb "comporter", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

[0162] In claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

DEMANDS [Claim 1] A storage installation (1) for liquefied gas comprising a supporting structure (2) and a sealed and thermally insulated tank (71), the tank (71) having at least one bottom wall (3) fixed to the supporting structure (2), in which the bottom wall (3) has a multilayer structure in one thickness direction including at least one sealed membrane (5, 7) and at least one thermally insulating barrier (4, 6) disposed between the sealed membrane (5, 7) and the supporting structure (2), in which the bottom wall (3) has a sump structure (9) locally interrupting the sealed membrane (5, 7) of the bottom wall (3), the sump structure (9) having a container (11) having a side wall (15), the container (11) being arranged through the thickness of the bottom wall (3) and being located at least partially in a well (8) formed in the supporting structure (2),the well (8) extending outwards from the tank (71) along a well axis (39), wherein the storage installation (1) comprises at least one base (19) connected to the supporting structure (2) and oriented along a first axis (X) parallel to the well axis (39), the sump structure (9) comprising, for said at least one base (19), a guiding device (18) in contact with said base (19) and having, in an installation configuration, one degree of freedom in rotation about a second axis (Y) perpendicular to the first axis (X) and one degree of freedom in rotation about a third axis (Z) perpendicular to the first axis (X) and perpendicular to the second axis (Y), enabling the sump structure (9) to be guided relative to the supporting structure (2). [Claim 2] Storage installation (1) according to claim 1, wherein the load-bearing structure (2) comprises a flat load-bearing wall pierced with an opening forming an inlet of the well (8), at least one base (19) being fixed to the flat load-bearing wall (2) around the opening forming the inlet of the well (8). [Claims] Storage installation (1) according to claim 1 or 2, wherein said at least one base (19) comprises a base (20) fixed to the supporting structure (2) and a contact element (21) having a convex spherical surface in cooperation with the guiding device (18). [Claim 4] Storage installation (1) according to claim 3, wherein the base (20) has a main body (201) fixed to the supporting structure (2) and carrying the contact element (21) along the first axis (X), and at least one protrusion (202) fixed to the supporting structure (2) and extending outwards from the sump structure (9). [Claim 5] Storage installation (1) according to any one of claims 3 to 4, wherein said at least one base (19) comprises a retaining plate (26) positioned between the base (20) and the contact element (21). [Claim 6] Storage installation according to any one of claims 1 to 5, wherein said at least one base (19) comprises a means for adjusting the height of said at least one base so as to ensure cooperation between the guiding device (18) and said at least one base (19). [Claim 7] Storage installation (1) according to any one of claims 1 to 6, wherein the guiding device (18) comprises a support plate (22) having an outer face (23), a part of the outer face (23) having a concave spherical surface and cooperating with the base (19). [Claim 8] Storage installation (1) according to claim 7, wherein the support plate (22) of the guiding device (18) has an inner face (24) comprising a means of attachment (25) to the sump structure (9). [Claim 9] Storage installation (1) according to claim 8, wherein the side wall (15) of the sump structure (9) comprises, for the guiding device (18), a hooking element (27) arranged opposite the inner face (24) of the support plate (22) and in cooperation with the hooking means (25). [Claim 10] A storage installation (1) according to claim 7 in combination with claim 5, wherein the storage installation further comprises an anti-uplift element (35) fixing the support plate (22) to said at least a base (19) so as to ensure permanent contact between said at least one base (19) and the guidance device (18). [Claim 1 1] Storage installation (1 ) according to any one of claims 1 to 10, wherein the container (1 1 ) and the well (8) are cylindrical in shape with a circular cross-section, and the storage installation (1 ) comprises at least two bases (19), such that said at least two bases (19) are separated by an angle 3607N, N being an integer corresponding to the number of bases, preferably N is equal to 4. [Claim 12] Storage installation (1) according to claim 11, wherein the storage installation (1) comprises four bases (19) distributed regularly around the well (8), the sealing membrane (5, 7) comprising a first series of parallel corrugations extending in a first direction and a second series of parallel corrugations extending in a second direction, two of the four bases (19) being aligned with the center of the container (11) in the first direction and two other of the four bases (19) being aligned with the center of the container (11) in the second direction. [Claim 13] Vessel (70) for the transport of a liquefied gas, the vessel (70) comprising a double hull (72) and a storage facility (1) according to any one of claims 1 to 12 disposed in the double hull (72). [Claim 14] Transfer system for a liquefied gas, the system comprising a vessel (70) according to claim 13, insulated pipes (73, 79, 76, 81) arranged to connect the tank (71) installed in the hull of the vessel to a floating or land-based storage facility (1) (77) and a pump to drive a flow of cold liquid product through the insulated pipes (73, 79, 76, 81) from or to the floating or land-based storage facility (1) to or from the tank (71) of the vessel (70). [Claim 15] Method for assembling a sump structure (9) of a storage facility (1) for liquefied gas, the storage facility (1) comprising a load-bearing structure (2) and a sealed and thermally insulated tank (71), wherein the method comprises the following steps: - provide the supporting structure (2) comprising a well (8), the well (8) extending outwards from the tank (71) along a well axis (39), - fix at least one base (19) to the supporting structure (2) so that at least one base (19) is arranged around the well (8) and oriented along a first axis (X) parallel to the axis of the well (39), - provide a sump structure (9) comprising a container (11) having a side wall (15), the sump structure (9) comprising for said at least a base (19) a guide device (18) having, in an installation configuration, a rotational degree of freedom about a second axis (Y) perpendicular to the first axis (X) and a rotational degree of freedom about a third axis (Z) perpendicular to the first axis (X) and perpendicular to the second axis (Y), - lower the sump structure (9) so as to place the guiding device (18) in contact with said at least one base (19) and so as to situate at least partially the container (11) in the well (8), - adjust the centering and inclination of the sump structure (9) using the guiding device (18), - fix the guiding device (18) to said at least one base (19). [Claim 16] Method of assembling a sump structure (9) of a storage facility (1) for liquefied gas, the storage facility (1) comprising a load-bearing structure (2) and a sealed and thermally insulated tank (71), wherein the method comprises the following steps: - provide the supporting structure (2) comprising a well (8), the well (8) extending outwards from the tank (71) along a well axis (39), - fix at least one base (19) to the supporting structure (2) so that at least one base (19) is arranged around the well (8) and oriented along a first axis (X) parallel to the axis of the well (39), - to bring into contact, for said at least one base (19), a guiding device (18) having, in an installation configuration, one degree of freedom in rotation around a second axis (Y) perpendicular to the first axis (X) and one degree of freedom in rotation around a third axis (Z) perpendicular to the first axis (X) and perpendicular to the second axis (Y), - provide a sump structure (9) comprising a container (11) having a side wall (15), - lower the sump structure (9) so as to hook the side wall (15) onto the guiding device (18) and so as to position at least partially the container (11) in the well (8), - adjust the centering and inclination of the sump structure (9) using the guiding device (18), - fix the guiding device (18) to said at least one base (19). [Claim 17] A method of loading or unloading a ship (70), wherein a cold liquid product is conveyed through insulated pipes (73, 79, 76, 81) from or to a floating or land-based storage facility (1) (77) to or from the tank (71) of the ship (70) according to claim 11.

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