Liquefied gas storage tank.

Abstract

Title: Liquefied gas storage tank. The present invention relates to a tank intended for a structure and configured to contain a liquefied gas, comprising a bottom wall 4, a ceiling wall and several side walls extending between the bottom wall 4 and the ceiling wall, the tank comprising at least one loading and / or unloading tower 8 extending along a vertical direction between the bottom wall 4 and the ceiling wall, the tower 8 comprising a base and at least three masts secured to the base, two of which masts form rear masts and the third mast forms a front mast, the tower 8 comprising at least one liquefied gas pumping member configured to supply fuel to at least one consumer of the structure, the tank comprising a sump 14 extending through the bottom wall 4 and in which the pumping member is at least partially arranged,characterized in that the sump 14 is arranged at least partly outside a perimeter P defined by a triangle with vertices centered on the masts 16, 16a, 16b and passing through a periphery of the front mast 16a, the sump 14 being arranged in an angular sector delimited by two axes A1, A2 each passing through a center of the tower 8 and forming an angle α of at most 90°. Figure 3.,

Description

Title of the invention: Liquefied gas storage tank.

[0001] The present invention relates to the field of storage and / or transport of a cargo of liquefied gas, such as liquefied natural gas, liquid ammonia or liquefied petroleum gas. More particularly, the invention relates to a loading and unloading tower for a liquefied gas storage tank.

[0002] Liquefied natural gas, commonly known by the acronym "LNG", or "Liquefied Natural Gas", is an important source of energy, composed of approximately 95% methane. More specifically, LNG is stored in the liquid state in a thermally insulated tank at a temperature close to -160°C, the LNG then occupying 1 / 600 of the volume that it would occupy in the gaseous state, thus facilitating its transport from one site to another.

[0003] Conventionally, the tank comprises a loading and unloading tower suspended from a cover which closes an opening of the tank. The loading and unloading tower may comprise a tripod-type structure, i.e. comprising three vertical masts connected to each other by crosspieces forming a lattice structure, said tower being guided by a support of the tank emerging from a bottom wall. The loading and unloading tower then comprises at least one unloading conduit and a pumping member whose function is to unload the cargo from the tank, said pumping member being connected to a drive device arranged outside the tank.Furthermore, in order to allow complete suction of the cargo, the suction element is arranged at least partly in a sump formed in the bottom wall of the tank which makes it possible to increase the quantity of cargo extracted by the unloading conduit while ensuring the immersion of the suction element in said cargo, thus preserving its integrity.

[0004] It is then known to arrange the unloading conduit in one of the masts of the loading and unloading tower. One of the disadvantages of such an arrangement of the loading and unloading tower then lies in the proximity between the support guiding the tower and the sump formed opposite the unloading conduit. Such proximity in fact limits the deformation property of the tank wall during storage of the cargo and during the cooling of the tank prior to its filling with liquefied gas, this deformation property being necessary to limit the deterioration of the tank. Furthermore, such an arrangement of the unloading conduit in one of the masts of the structure of the tower complicates its accessibility for an operator. It is thus understood that such a configuration of the tank and more particularly of the loading and unloading tower, increases the mechanical constraints on said tank, necessary for the storage of liquefied gas, while limiting the accessibility of the unloading conduit.

[0005] The present invention falls within this context by proposing an arrangement of the pumping member which is different from the positioning solutions already existing, making it possible on the one hand to facilitate access to the pumping member and to the discharge conduit and on the other hand to reduce the mechanical constraints imposed on the storage tank.

[0006] The main subject of the present invention is thus a tank intended for a structure and configured to contain a liquefied gas, comprising a bottom wall, a ceiling wall and several side walls extending between the bottom wall and the ceiling wall, the storage tank comprising at least one loading and / or unloading tower extending along a vertical direction between the bottom wall and the ceiling wall, the tower comprising a base and at least three masts secured to the base, two of which form rear masts and the third mast forms a front mast, the tower comprising at least one liquefied gas pumping member and a sump extending through the bottom wall and in which the pumping member is at least partially arranged, characterized in that the sump is arranged at least partly outside a perimeter defined by a triangle with vertices centered on the masts and passing through a periphery of the front mast,the sump being arranged in an angular sector delimited by two axes each passing through a center of the tower and forming an angle of at most 90°.

[0007] The tower thus makes it possible to load or unload liquefied gas into or from a tank in which the tower is installed.

[0008] The perimeter delimited by the triangle and the front mast corresponds to an axial projection of the three masts of the tower on the bottom wall of the storage tank, this projection being visible in a plane perpendicular to the vertical direction of the tower. The triangle has three vertices which are each located at the center of each mast, the perimeter encompassing an external periphery of the front mast.

[0009] Thus, advantage is taken of the location of the sump in this area delimited by the various characteristics described above, this arrangement making it possible to move the sump and the pumping member away from the base of the tower. The distance of the sump reduces the stiffening of the bottom wall of the tank, the distance of the pumping member facilitating the assembly, installation, maintenance or other actions to be carried out on said pumping member.

[0010] According to an optional feature, the pumping member is configured to supply fuel to at least one consumer of the structure. According to another solution, the pumping member is configured to pump the cargo out of the tank, in particular with a view to unloading it.

[0011] According to an optional characteristic of the invention, the sump is arranged beyond an arc of a circle centered on the center of the tower, said arc of a circle tangent to a rear zone of the front mast of the tower.

[0012] The term "center of the tower" also means the center of a circle passing through the center of the three masts of the tower. This center is taken as a reference for the arc of a circle passing through the front mast constituting a delimitation of an area in which the sump is arranged.

[0013] More precisely, this area in which the sump is arranged is defined in response to at least three conditions which are that the sump must be arranged outside the perimeter, that it is arranged in the angular sector previously described and that it is beyond the arc of a circle centered on the tower and passing through a rear periphery of the front mast. In other words, the sump is in an area of ​​the back wall defined on the one hand by an angular sector delimited by two axes each passing through a center of the tower and forming an angle of at most 90°, the front mast being arranged in the angular sector, the area being defined on the other hand by an arc of a circle centered on the center of the tower, the arc of a circle tangent to the rear area of ​​the front mast of the tower.

[0014] According to an optional feature of the invention, the angle of the angular sector is open on the front mast. In other words, the front mast is arranged in the angular sector while participating in determining the exclusion perimeter.

[0015] According to an optional feature of the invention, the tower comprises at least one unloading member arranged between the front mast and one or other of the rear masts. An axial projection of this unloading member, here a pump, intersects the triangle which forms part of the exclusion perimeter. It is understood that the pumping member which is arranged in the sump is intended to suck in liquefied gas to supply fuel to at least one consumer of the structure or to unload the liquefied gas from the storage tank. The unloading member is intended solely for unloading liquefied gas from the storage tank.

[0016] According to another optional characteristic of the invention, the unloading member is a first unloading member, the tower comprising a second unloading member, the first unloading member being arranged between the front mast and one of the rear masts, the second unloading member being arranged between the front mast and the other rear mast and according to an axial projection identical to that of the first unloading member.

[0017] According to another optional characteristic of the invention, one of the axes participating in delimiting the angular sector is intersecting with an axis passing through the center of the tower and the center of the front mast, forming an angle of between 40° and 50°.

[0018] According to another optional characteristic of the invention, one of the axes participating in delimiting the angular sector is secant with an axis passing through the center of the tower and the center of the foremast at a 45° angle.

[0019] According to another optional characteristic of the invention, the arc of a circle has a minimum radius equal to 1600 mm.

[0020] According to another optional characteristic of the invention, the arc of a circle has a radius of 1650mm or 1700mm.

[0021] According to another optional characteristic of the invention, the arc of a circle is a minimal arc of a circle, the sump being arranged between the minimal arc of a circle and a maximum arc of a circle centered on the center of the tower and with a maximum radius equal to 3400 mm.

[0022] According to another optional characteristic of the invention, the tower comprises a system for loading the tank with liquefied gas, a projection of the loading system on the bottom wall being arranged in the angular sector, a location of the sump in the angular sector being distinct from the projection of the loading system. By "distinct" is meant the fact that the location of the sump and the axial projection of the loading system do not intersect, that is to say that the sump is not arranged totally or partially below the loading system.

[0023] According to another optional characteristic of the invention, the angular sector comprises a first sub-sector and a second sub-sector symmetrical with respect to an axis passing through the center of the tower and the center of the front mast.

[0024] According to one aspect, a projection of the loading system on the bottom wall is disposed in the first sub-sector while the sump is disposed in the second sub-sector.

[0025] Advantageously, the sump and a projection of the loading system on the bottom wall are arranged in the same sub-sector.

[0026] According to another optional feature of the invention, a straight line passing through the center of the loading system and the center of the front mast also passes through the sump. This straight line passes more precisely through the sump, without necessarily passing through the center of said sump.

[0027] According to another optional characteristic of the invention, an axis passing through the center of the tower and through the center of the front mast passes through the sump.

[0028] According to another optional characteristic of the invention, at least the bottom wall of the storage tank comprises at least one thermally insulating layer and a sealing membrane carried by the thermally insulating layer, the sealing membrane participating in defining an internal volume of the tank, the sealing membrane comprising several metal strips having raised edges and connected to each other by their raised edges.

[0029] The present invention also relates to a structure comprising a storage tank as described in the present document, the structure being chosen from a liquefied gas transport vessel, barge, reliquefaction unit, gasification unit, gravity platform or land-based structure.

[0030] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and several examples of embodiment given for informational and non-limiting purposes with reference to the appended schematic drawings on the other hand, in which:

[0031] [Fig-1] is a schematic representation of a ship seen from above and equipped with a storage tank for a liquefied gas according to the invention and comprising a loading and / or unloading tower;

[0032] [Fig.2] is a perspective representation of the tower illustrated in [Fig. 1];

[0033] [Fig.3] is a schematic section of a first example of positioning a sump in a wall of the tank illustrated in [Fig.l];

[0034] [Fig.4] is a schematic section of a second example of positioning of a sump in a wall of the tank illustrated in [Fig.l].

[0035] The features, variants and different embodiments of the invention may be combined with each other, in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0036] In the figures, the elements common to several figures retain the same reference.

[0037] In the detailed description which follows, the terms “longitudinal”, “transverse” and “vertical” refer to the orientation of a storage tank according to the invention. A longitudinal direction corresponds to a main direction of elongation of the storage tank, this longitudinal direction being parallel to a longitudinal axis L of a reference frame L, V, T illustrated in the figures. A vertical direction corresponds to a direction along which a loading and / or unloading tower mainly extends, this vertical direction being parallel to a vertical axis V of the reference frame L, V, T and this vertical axis V being perpendicular to the longitudinal axis L. Finally, a transverse direction corresponds to a direction parallel to a transverse axis T of the reference frame L, V, T, this transverse axis T being perpendicular to the longitudinal axis L and the vertical axis V.

[0038] [Fig.l] illustrates a structure 1 corresponding here to a ship for transporting liquefied gas. In order to transport the liquefied gas, the ship comprises at least one tank 2 for storing and / or transporting the liquefied gas comprising at least one bottom wall 4, visible in figures 2 to 4, and a ceiling wall, here not visible and opposite each other in a vertical direction V of the tank 2, said walls being connected to each other by side walls 6. The bottom wall 4, the ceiling wall and the side walls 6 participate in delimiting a storage volume for the liquefied gas.

[0039] The tank 2 is configured to store a gas in the liquid state, this gas being able to be liquefied natural gas, liquid ammonia or even liquefied petroleum gas for example. These gases are in the liquid state at low temperatures, generally below 0°C and being able to go down to -163°C for liquid natural gas, for example.

[0040] Such a tank 2 may be installed for example on a structure 1 intended for the transport of liquefied gas, such as a ship or a barge, for the treatment of liquefied gas, such as a reliquefaction unit and / or a gasification unit, or even for the storage of liquefied gas, such as a land structure or a gravity platform.

[0041] Furthermore, at least the bottom wall 4 comprises at least one thermally insulating layer and a sealing membrane carried by the thermally insulating layer. Advantageously, each of the walls of the tank 2 comprises at least one thermally insulating layer and a sealing membrane.

[0042] As visible in [Fig.l], the walls of the tank 2 comprise at least one primary space participating in delimiting an internal volume of the tank 2 and a secondary space carrying the primary space, each of the spaces comprising a thermally insulating layer and a sealing membrane. It is understood that the walls of the tank 2 are thus composed of layers and membranes superimposed on top of each other.

[0043] More precisely, the walls of the tank 2 comprise, from the outside of the tank 2 towards the internal volume of said tank 2, a secondary thermally insulating layer, a secondary sealing membrane carried by the secondary thermally insulating layer, a primary thermally insulating layer arranged on the secondary sealing membrane and a primary sealing membrane carried by the primary thermally insulating layer, the primary sealing membrane participating in delimiting the internal volume of the tank 2. The thermally insulating layers are formed of thermally insulating blocks, or boxes made of wooden plywood panels filled with a thermally insulating material.

[0044] In the remainder of the description, the characteristics described in relation to the term “waterproofing membrane” may relate to the primary waterproofing membrane and / or to the secondary waterproofing membrane, unless otherwise stated.

[0045] The sealing membrane itself comprises several metal strips, each having an external face in contact with the primary thermally insulating layer and an internal face facing the internal volume of the tank 2. The metal strips metal strips also have a folded edge, the metal strips being connected to each other via their folded edges. In other words, the folded edges of two adjacent metal strips are made integral with each other, for example by welding, thereby making the metal strips integral with each other. The attachment of the metal strips to each other by means of their folded edges promotes elasticity of the sealing membrane, in particular when the walls of the tank 2 undergo thermal deformations during the loading and / or unloading of the tank 2 with liquefied gas.

[0046] In addition, and as visible in Figures 1 and 2, the tank 2 comprises a loading and / or unloading tower 8 extending vertically between the bottom wall 4 and the ceiling wall. The tower 8 is configured to load and / or unload the liquefied gas into and / or from the tank 2, and comprises a pumping member 10 capable of sucking up the liquefied gas contained in the tank 2. For example, the pumping member 10 is a pump which can recover liquefied gas flowing into the sump 14 in order, for example, to supply a consumer of a ship in which the tank 2 is installed, such a consumer being, for example, an engine of an electricity generator.

[0047] More particularly, the ceiling wall comprises an opening in which a cover 12 constituting the tank 2 is arranged so as to close the storage volume of the tank 2 in a sealed manner, in particular by extending the ceiling wall at the level of the opening. As visible in [Fig.2], the cover 12 is at least partly crossed by the tower 8 so as to be able to load or unload liquefied gas to or from the storage space of the tank 2.

[0048] The tank 2 further comprises at least one sump 14 in which the pumping member 10 is housed at least partially. The sump 14 is arranged through the bottom wall 4 of the tank 2 and thus makes it possible to suck in the liquefied gas flowing into the tank 2.

[0049] The tower 8, particularly visible in [Fig.2], comprises a structure which extends mainly along a main direction of extension parallel to the vertical direction V, having an upper end and a lower end, the upper end facing the ceiling wall while the lower end faces the bottom wall 4. More particularly, the tower 8 is formed by at least three masts 16, or otherwise called a tripod structure, and a base 18 advantageously arranged at its lower end, making the three masts 16 integral with each other.

[0050] More precisely, the structure of the loading tower 8 comprises at least three masts 16 secured to each other by means of a lattice structure 20, each of the three masts 16 passing through the cover of the tank 2. A front mast 16a of the tower 8 and two rear masts 16b of the tower 8 are then defined, defined in a direction of the ship's progress, visible in [Fig.l], under normal sailing conditions, the forward mast 16a being the mast of tower 8 furthest forward in tank 2.

[0051] In addition to the pumping member 10, the tower 8 comprises at least one unloading member 22, 24 for the liquefied gas present in the tank 2, the unloading member 22, 24 being arranged between the front mast 16a and one or other of the rear masts 16b, the pumping member 10 being configured to supply fuel to at least one consumer of the structure 1. By “arranged between the front mast 16a and one or other of the rear masts 16b”, it is meant that a line passing through the center of the front mast 16a and the center of said rear mast 16b passes through the unloading member 22, 24.

[0052] In this configuration, the unloading member 22, 24 is intended solely for unloading liquefied gas from the tank 2, the pumping member 10, which is arranged in the sump 14, being, as a reminder, intended to suck up liquefied gas to either supply fuel to at least one consumer of the structure 1 or to unload the liquefied gas from the tank 2.

[0053] As illustrated in Figures 3 and 4, the tower 8 comprises a first unloading member 22 and a second unloading member 24, the first unloading member 22 being arranged between the front mast 16a and one of the rear masts 16b, the second unloading member 24 being arranged between the front mast 16a and the other rear mast 16b. The unloading members 22, 24 are aligned with each other along a direction parallel to the transverse direction T.

[0054] According to the invention and as visible in [Fig. 3], the sump 14 is arranged at least partly outside a perimeter P defined by a triangle passing through the center of the three masts and through the front mast 16a, in an angular sector delimited by two axes A1, A2 each passing through a center of the tower 8 and forming an angle a of at most 90°. The perimeter envisaged here is a shape which combines a triangle and a circle, the latter being an axial projection of the front mast 16a on the back wall, its center then being placed at a vertex of the triangle.

[0055] The sump 14 is also arranged beyond an arc of a circle C1 centered on the center of the tower 8, said arc of a circle C1 tangent to a rear zone of the front mast 16a of the tower 8. More precisely, the sump 14 is arranged in a zone 26 defined in response to at least three conditions which are that the sump 14 must be arranged outside the perimeter P which combines the triangle and the front mast projection, that it is arranged in the angular sector previously described and that it is beyond the arc of a circle C1 centered on the tower 8 and which tangent to the rear zone of the front mast 16a.

[0056] According to one aspect of the invention, the pumping member 10 is also arranged at least partly outside the perimeter P defined above, in the angular sector delimited by the two axes A1, A2 each passing through the center of the tower 8 and forming an angle of at most 90°, and finally beyond the arc of a circle C1 centered on the center of tower 8 and which tangents the rear zone of the front mast 16a of tower 8. In fact, the pumping member 10 is less partly arranged in the sump 14.

[0057] The perimeter P delimited at least in part by the triangle with vertices centered on the masts corresponds to an axial projection of the center of each mast joined by sides of the triangle, this projection being visible in a plane perpendicular to the vertical direction V.

[0058] It is noted that each of the masts 16 has an inner face 28 oriented towards the other masts 16 and an outer face 30 facing the exterior of the tower 8, the distinction between the inner face 28 and the outer face 30 being appreciated for example here with regard to the sides which form the triangle represented in figures 3 and 4.

[0059] As the front mast 16a is part of the exclusion perimeter, it is understood that the location of the sump 14 is distinct from a projection of the front mast 16a on the angular sector, as illustrated in Figures 3 and 4 by a cross on the projection of the front mast 16a in the angular sector.

[0060] As for the angular sector, it is here defined by the two axes A1, A2 passing through the center of the tower 8, that is to say the center of a circle passing through the center of the three masts 16 of the tower 8. In other words, the two axes A1, A2 intersect each other at the center of the tower 8. These two axes A1, A2 form an angle of at most 90°, and participate in defining at least partly transversely the zone 26 in which the sump 14 and the pumping member are arranged.

[0061] Advantageously, each of the axes A1, A2 passes through one of the unloading members 22, 24 of the tower 8. For example, and as illustrated schematically in FIGS. 3 and 4, each of the axes A1, A2 passes through an external periphery of the unloading members 22, 24.

[0062] Furthermore, the angle of the angular sector is open on the front mast 16a. In other words, the front mast 16a is transversely framed by the axes A1, A2 defining the angular sector.

[0063] As visible in [Fig.3], one of the axes A1, A2 participating in delimiting the angular sector is intersecting with an axis passing through the center of the tower 8 and through the center of the front mast 16a, forming an angle between 40° and 50°. Advantageously, the angle is 45°.

[0064] Even more advantageously, each of the axes A1, A2 participating in delimiting the angular sector is intersecting with an axis passing through the center of the two rear masts 16b, each forming an angle of between 40° and 50°.

[0065] The angular sector comprises two angular sub-sectors which are symmetrical with respect to the axis passing through the center of the tower 8 and the center of the front mast 16a, this perpendicular axis also corresponding to the longitudinal axis of the tank.

[0066] Finally, concerning the arc of a circle Cl, it is inscribed in a circle centered on the center of tower 8, that is to say the center of the circle passing through the center of each of the masts 16 of tower 8, and constitutes a minimum limit of zone 26 in which sump 14 is arranged. It is understood that the location of sump 14 in zone 26 is located beyond this arc of circle Cl, towards the front of tank 2.

[0067] As visible in Figures 3 and 4, the arc of a circle C1 is tangent to a rear zone of the front mast 16a of the tower 8, that is to say a zone of the front mast 16a which is located inside the triangle which helps to form the perimeter P. Advantageously, the arc of a circle C1 passes through the inner face 28 of the front mast 16a. It is understood that the sump 14 can be, for example, arranged at the front of the front mast 16a, or be aligned with respect to the front mast 16a, transversely, and generally at any location in the zone 26.

[0068] The arc of a circle Cl has a minimum radius of 1600mm, 1650mm or 1700mm, this dimension being measured in a plane perpendicular to the vertical direction V between the center of the tower 8 and, here, the inner face 28 of the front mast 16a.

[0069] According to the invention, the zone 26 in which the sump 14 is arranged is longitudinally delimited by the arc of a circle C1 previously described, which is a first arc of a circle C1, and a second arc of a circle C2, the zone 26 thus extending between the first arc of a circle C1 and the second arc of a circle C2 and between the axes A1 and A2 which border the angular sector according to the invention.

[0070] The first arc of a circle C1 corresponds more precisely to a minimum arc of a circle while the second arc of a circle C2 corresponds to a maximum arc of a circle. Similar to the first arc of a circle C1, the second arc of a circle C2 is centered on the center of the tower 8, and has a maximum radius equal to 3400mm, advantageously between 3200mm and 3400mm. Advantageously, the second arc of a circle C2 has a radius of 3300mm.

[0071] It is understood from the above that the invention thus relates to a zone 26 of the bottom wall 4 of the tank 2 in which the sump 14 and the pumping member 10 are arranged. This zone 26 is at least delimited transversely by the axes A1, A2 defining the angular sector, longitudinally at least by the first arc of a circle C1 and advantageously by the second arc of a circle C2, while excluding the interior of the perimeter formed by the perimeter P of the tower 8.

[0072] Two exemplary embodiments of the invention will now be described in which the location of the sump 14 in the zone 26 is different. A first exemplary embodiment of the invention, with reference to [Fig. 3], will first be described, then a second exemplary embodiment of the invention, with reference to [Fig. 4], will be described following the description of the first exemplary embodiment.

[0073] As illustrated in [Fig.3], an axis 34 passing through the center of the tower 8 and the center of the foremast 16a passes through the sump 14, the axis 34 being substantially parallel to the longitudinal direction L. In other words, the sump 14, the front mast 16a and the center of the tower 8 are aligned with each other. It is understood that in this arrangement, the sump 14 is sufficiently far from the tower 8 to limit the stiffening of the bottom wall 4 of the tank 2 that its installation requires. In addition, the pumping member 10 is also aligned with the front mast 16a and the center of the tower 8, which facilitates the operations of installation, assembly and / or maintenance of said pumping member 10 in the tank 2.

[0074] As illustrated in [Fig. 4], the tower 8 comprises the system 36 for loading the tank 2 with liquefied gas, a projection of the loading system 36 on the bottom wall 4 being arranged in the zone 26, a location of the sump 14 in the zone 26 being distinct from the projection of the loading system 36. “Distinct” is understood to mean that the location of the sump 14 and the projection of the loading system 36 do not overlap, i.e. the sump 14 is not arranged below the loading system 36. The distinct arrangement of the location of the sump 14 and the projection of the loading system 36 makes it possible to avoid spraying liquefied gas directly into the sump 14, and therefore at least partly onto the pumping member 10, when loading the tank 2 with liquefied gas. In addition, a superposition of the loading system 36 and the sump 14 would complicate the installation and assembly of the tower 8 in the tank 2.

[0075] As visible in [Fig.4], the angular sector is separated into a first sub-sector and a second sub-sector by the axis 34 passing through the center of the tower 8 and the center of the front mast 16a, the projection of the loading system 36 being arranged in the first sub-sector while the sump 14 is arranged in the second sub-sector. In other words, the location of the sump 14 and the projection of the loading system 36 transversely frame the front mast 16a.

[0076] Advantageously, a straight line passing through the center of the projection of the loading system 36 and through the center of the front mast 16a also passes through the sump 14. This straight line passes more precisely through the sump 14, without necessarily passing through the center of said sump 14.

[0077] The present invention cannot, however, be limited to the means and configurations described and illustrated here and it also extends to any equivalent means and configuration as well as to any technically operative combination of such means. In particular, the description of the location of the sump 14 in the first exemplary embodiment and in the second exemplary embodiment is not limiting of the invention, these examples being only illustrations of the implementation of the invention. Thus, and as a reminder, the invention relates to the fact that the sump 14 is arranged in a zone 26 delimited at least by the angular sector defined by the two axes A1, A2, the perimeter P of the tower 8 and optionally the arc of a circle CL

Claims

Claims

1. Tank (2) intended for a structure (1) and configured to contain a liquefied gas, comprising a bottom wall (4), a ceiling wall and several side walls (6) extending between the bottom wall (4) and the ceiling wall, the tank (2) comprising at least one loading and / or unloading tower (8) extending along a vertical direction between the bottom wall (4) and the ceiling wall, the tower (8) comprising a base (18) and at least three masts (16, 16a, 16b) integral with the base (18) of which two masts (16) form rear masts (16b) and the third mast (16) forms a front mast (16a), the tower (8) comprising at least one pumping member (10) for the liquefied gas and a sump (14) extending through the wall of bottom (4) and in which the pumping member (10) is at least partially arranged,characterized in that the sump (14) is arranged at least partly outside a perimeter (P) defined by a triangle with vertices centered on the masts (16, 16a, 16b) and passing through a periphery of the front mast (16a), the sump (14) being arranged in an angular sector delimited by two axes (A1, A2) each passing through a center of the tower (8) and forming an angle (a) of at most 90°, the angle (a) of the angular sector being open on the front mast (16a).,

2. Tank (2) according to claim 1, in which the sump (14) is arranged beyond an arc of a circle (Cl) centered on the center of the tower (8), said arc of a circle (Cl) tangent to a rear zone of the front mast (16a) of the tower (8).

3. Tank (2) according to any one of claims 1 or 2, in which the tower (8) comprises at least one unloading member (22, 24) for the liquefied gas arranged between the front mast (16a) and one or other of the rear masts (16b).

4. Tank (2) according to any one of claims 1 to 3, in which one of the axes (A1, A2) participating in delimiting the angular sector is secant with an axis passing through the center of the tower (8) and a center of the front mast (16a) forming an angle between 40° and 50°.

5. Tank (2) according to claim 2, in which the arc of a circle (Cl) has a minimum radius equal to 1600 mm.

6. Tank (2) according to any one of claims 2 or 5, in which the arc of a circle (Cl) is a minimal arc of a circle, the sump (14) being arranged between the minimal arc of a circle (Cl) and an arc of a circle (C2) maximum centered on the center of the tower (8) and maximum radius equal to 3400mm.

7. Tank (2) according to any one of claims 1 to 6, in which the tower (8) comprises a system (36) for loading the tank (2) with liquefied gas, a projection of the loading system (36) on the bottom wall (4) being arranged in the angular sector, a location of the sump (14) in the angular sector being distinct from the projection of the loading system (36).

8. Tank (2) according to any one of claims 1 to 7, in which the angular sector comprises a first sub-sector and a second sub-sector symmetrical with respect to an axis passing through the center of the tower (8) and the center of the front mast (16a).

9. Tank (2) according to claims 7 and 8, wherein a projection of the loading system (36) on the bottom wall (4) is arranged in the first sub-sector while the sump (14) is arranged in the second sub-sector.

10. Tank (2) according to claims 7 and 8, in which the sump (14) and a projection of the loading system (36) on the bottom wall (4) are arranged in the same sub-sector.

11. Tank (2) according to any one of claims 1 to 8 or 10, in which an axis (34) passing through the center of the tower (8) and through the center of the front mast (16a) passes through the sump (14).

12. Tank (2) according to any one of claims 1 to 11, in which at least the bottom wall (4) of the tank (2) comprises at least one thermally insulating layer and a sealing membrane carried by the thermally insulating layer, the sealing membrane participating in defining an internal volume of the tank (2), the sealing membrane comprising several metal strips having raised edges and connected to each other by their raised edges.

13. Structure (1) comprising a tank (2) according to any one of claims 1 to 12, the structure (1) being chosen from a liquefied gas transport vessel, a barge, a reliquefaction unit, a gasification unit, a gravity platform or a land-based structure.

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