Liquefied gas storage tank

Abstract

To provide a tank intended for a structure and configured to contain a liquefied gas.SOLUTION: A tank includes a bottom wall 4, a top wall, and a plurality of side walls extending between the bottom wall 4 and the top wall. The tank includes at least one loading / unloading tower 8 extending between the bottom wall 4 and the top wall along a vertical direction, the tower 8 includes a base and at least three poles secured to the base, two poles of them form rear poles, and the third pole forms a front pole. The tower 8 includes at least one pumping member for pumping the liquefied gas, and the pumping member is configured to supply a fuel to at least one consumption element of the structure. The tank includes a sump 14 which extends through the bottom wall and in which the pumping member is at least partially arranged.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to the field of storage and / or cargo transportation of liquefied gases, such as liquefied natural gas, liquid ammonia, and liquefied petroleum gas. More specifically, the present invention relates to a tower for the loading and unloading of liquefied gas storage tanks. [Background technology]

[0002] Liquefied natural gas, commonly known by its acronym "LNG", is an important energy source and is composed of approximately 95% methane. More specifically, LNG is stored in its liquid state in insulated tanks at around -160°C. At this temperature, LNG occupies 1 / 600th of the volume it would occupy in its gaseous state, making it easier to transport from one place to another.

[0003] Conventionally, the tank comprises a loading / unloading tower suspended from a cover closing the opening of the tank. The loading / unloading tower may comprise a tripod structure, i.e. a tripod structure with three vertical poles connected to each other by cross members forming a lattice structure. Said tower is guided by the support of the tank emerging from the bottom wall. The loading / unloading tower comprises at least one discharge pipe and a pumping member having the function of discharging the cargo from the tank. Said pumping member is connected to a drive arranged outside the tank. Furthermore, a suction element is arranged at least partially in a sump formed in the bottom wall of the tank so as to allow a complete suction of the cargo. This allows to increase the amount of cargo drawn by the discharge pipe while ensuring that the suction element is immersed in said cargo, thus guaranteeing its completeness.

[0004] It is known to arrange the discharge pipe on one of the poles of the loading / unloading tower. One of the disadvantages of such an arrangement of the loading / unloading tower is the proximity of the support guiding the tower to the sump formed on the opposite side of the discharge pipe. This proximity very much limits the deformation characteristics of the tank wall during the storage of the cargo and during the cooling of the tank prior to filling with liquefied gas. This deformation characteristic is necessary to limit the deterioration of the tank. Moreover, this arrangement of the discharge pipe on one of the poles of the tower structure complicates the accessibility of the operator to the discharge pipe. It is therefore understood that such a construction of the tank, and more particularly of the loading / unloading tower, limits the accessibility of the discharge pipe while increasing the mechanical stresses on said tank necessary for the storage of liquefied gas. Summary of the Invention

[0005] The present invention falls within this context by proposing an arrangement of the pumping members that differs from existing layout solutions and that allows, on the one hand, to facilitate access to the pumping members and the discharge pipes and, on the other hand, to reduce the mechanical stress on the storage tank.

[0006] The main object of the present invention is therefore a tank intended for structural use and adapted to contain liquefied gas, said tank comprising a bottom wall, a top wall and a number of side walls extending between said bottom wall and said top wall, said tank comprising at least one inlet and / or outlet tower extending between said bottom wall and said top wall along a vertical direction, said tower comprising a base and at least three poles fixed to said base, two of which form rear poles and a third pole forming a front pole, said tower comprising at least one member for pumping said liquefied gas and a sump extending through said bottom wall and in which said pumping member is at least partially arranged, said sump being at least partially arranged outside a perimeter (P) defined by a triangle with apexes centered on said poles and passing through the edge of said front pole, said sump being arranged within an angular sector defined by two axes, each passing through the center of the tower and forming an angle of at most 90°.

[0007] This tower therefore makes it possible to transport liquefied gas to or from the tank in which it is installed.

[0008] The perimeter defined by the triangle and the front pole corresponds to the axial projection of the three poles of the tower onto the bottom wall of the storage tank. This projection can be seen in a plane perpendicular to the vertical of the tower. The triangle has three vertices, one at the center of each pole. The perimeter encompasses the outer edge of the front pole.

[0009] It is therefore advantageous to locate the sump in this area defined by the various features described above. This location allows the sump and pumping members to be located away from the base of the tower. The distance from the sump reduces the stiffness of the bottom wall of the tank. The spacing of the pumping members facilitates mounting, installation, maintenance or other operations performed on said pumping members.

[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 cargo from the tank, in particular for removing the cargo.

[0011] According to an optional feature of the invention, the sump is located outside an arc of a circle about the centre of the tower, the arc being tangent to the aft zone of the front pole of the tower.

[0012] Further, "tower center" means the center of a circle passing through the centers of the three poles of the tower, which center is referenced to an arc passing through the forward pole that constitutes the boundary of the zone in which the sump is located.

[0013] More precisely, this zone in which the sump is located is determined according to at least three conditions: it must be located outside the periphery, it must be located within the above-mentioned angular sector, and it must be outside the arc of a circle centered on the tower and passing through the rear edge of the front pole. In other words, the sump is in a certain zone of the bottom wall. On the one hand, the zone is determined by an angular sector defined by two axes, each passing through the center of the tower and forming an angle of at most 90°, and the front pole is located within the angular sector. On the other hand, the zone is determined by an arc of a circle centered on the center of the tower and tangent to the rear zone of the front pole of the tower.

[0014] According to an optional feature of the invention, the angle of the angular sector is open at the front pole, in other words the front pole is located within the angular sector while participating in the identification of the exclusion perimeter.

[0015] According to an optional feature of the invention, the tower comprises at least one discharge member arranged between the front pole and one or the other of the rear poles. The axial projection of this discharge member, here a pump, intersects with a triangle forming part of the clearance perimeter. It is understood that the pumping member arranged in the sump is intended to suck in liquefied gas in order to supply fuel to at least one consumer of the structure or to discharge liquefied gas from the storage tank. In contrast, the discharge member is only intended to discharge liquefied gas from the storage tank.

[0016] According to another optional feature of the invention, the discharge member is a first discharge member and the tower comprises a second discharge member, the first discharge member being arranged between one of the front pole and the rear pole and the second discharge member being arranged between the other of the front pole and the rear pole, the axial projection of which is identical to that of the first conveying member.

[0017] According to another optional feature of the invention, one of the axes participating in defining the angular sector secants an axis passing through the centre of the tower and the centre of the front pole to form an angle of between 40° and 50°.

[0018] According to another optional feature of the invention, one of the axes participating in defining the angular sector intersects an axis passing through the centre of the tower and the centre of the front pole to form an angle of 45°.

[0019] According to another optional feature of the invention, the radius of said circular arc is at a minimum equal to 1600 mm.

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

[0021] According to another optional feature of the invention, said arc is a minimum arc, said sump is located between said minimum arc and a maximum arc centered on said center of said tower, and the radius of said maximum arc (C2) is at most equal to 3400 mm.

[0022] According to another optional feature of the invention, the tower comprises a liquefied gas delivery system from the tank, the projection of said delivery system on said bottom wall being located in said angular sector and the position of said sump in said angular sector being different from said projection of said delivery system, "different" meaning that the position of the sump and the axial projection of the delivery system do not overlap, i.e. the sump is not located totally or partially below the delivery system.

[0023] According to another optional feature 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 centre of the tower and the centre of the front pole.

[0024] According to one aspect of the invention, the projection of the delivery system onto the bottom wall is located in the first sub-sector, while the sump is located in the second sub-sector.

[0025] Conveniently, the sump and the projection of the delivery system onto the bottom wall are located in the same sub-sector.

[0026] According to another optional feature of the invention, the line passing through the centre of the projection of the delivery system and the centre of the front pole also passes through the sump, more precisely, this line passes through the sump, but not necessarily through its centre.

[0027] According to another optional feature of the invention, an axis passing through the centre of the tower and the centre of the front pole passes through the sump.

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

[0029] An object of the invention is also a structure comprising a storage tank as described in this document, the structure being selected from a liquefied gas carrier, a barge, a reliquefaction unit, a gasification unit, a gravity platform, or a land-based structure.

[0030] Other characteristics, details and advantages of the invention will become more apparent from both the description which follows and from some exemplary embodiments thereof, given by way of illustration and not of limitation with reference to the attached schematic drawings, in which: [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a schematic view from above of a ship provided with a liquefied gas storage tank according to the invention, the liquefied gas storage tank comprising an input and / or output tower. [Diagram 2] FIG. 2 is a perspective view of the tower shown in FIG. [Diagram 3] FIG. 3 is a schematic cross-sectional view of a first example of a sump positioned in the wall of the tank shown in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view of a second example of a sump positioned in the wall of the tank shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The features, variants, and different embodiments of the invention can be combined with one another in various combinations, provided they are not mutually incompatible or exclusive. In particular, variants of the invention can be envisaged that consist of only selected features of the following description in isolation from the other features described, provided that this selection of features is sufficient to provide a technical advantage and / or to differentiate the invention from the prior art.

[0033] In the drawings, elements common to multiple drawings are given the same reference numerals.

[0034] In the detailed description that follows, the terms "longitudinal", "lateral" and "vertical" refer to the orientation of the storage tank according to the invention. The longitudinal direction corresponds to the direction in which the storage tank mainly extends. This longitudinal direction is parallel to the longitudinal axis L of the reference frames L, V, T shown in the drawings. The vertical direction corresponds to the direction in which the loading and / or unloading tower mainly extends. This vertical direction is parallel to the vertical axis V of the reference frames L, V, T. This vertical axis V is perpendicular to the longitudinal axis L. Finally, the transverse direction corresponds to the direction parallel to the transverse axis T of the reference frames L, V, T. This transverse axis T is perpendicular to the longitudinal axis L and to the vertical axis V.

[0035] Figure 1 shows a structure 1, which in this specification corresponds to a liquefied gas carrier. In order to transport liquefied gas, the ship comprises at least one tank 2 for storing and / or transporting liquefied gas. The tank 2 comprises at least one bottom wall 4, which can be seen in Figures 2 to 4, and a top wall, not shown, which are opposite each other in the vertical direction of the tank 2. These walls are connected to each other by side walls 6. The bottom wall 4, the top wall and the side walls 6 participate in defining a storage volume for the liquefied gas.

[0036] The tank 2 is configured to store gas in liquid state. This gas can be, for example, liquefied natural gas, liquid ammonia, and liquefied petroleum gas. These gases are in liquid state at low temperatures. The low temperatures are generally below 0°C and can range, for example, down to -163°C for liquefied natural gas.

[0037] Such a tank 2 may be installed on a structure 1, such as, for example, a ship or barge intended for transporting liquefied gas, a reliquefaction and / or gasification unit intended for processing liquefied gas, and a land-based structure or gravity platform intended for storing liquefied gas.

[0038] Furthermore, at least the bottom wall 4 is provided with at least one insulating layer and a sealing membrane supported by the insulating layer. Advantageously, each of the walls of the tank 2 is provided with at least one insulating layer and a sealing membrane.

[0039] As can be seen from Fig. 1, the wall of the tank 2 comprises at least one primary space which participates in defining the internal volume of the tank 2 and a secondary space which supports the primary space. Each of these spaces comprises an insulating layer and a sealing membrane. It can thus be seen that the wall of the tank 2 is made up of layers and membranes superimposed on one another.

[0040] More specifically, the wall of the tank 2 comprises, from the outside of the tank towards the internal volume of said tank 2, a secondary insulation layer, a secondary sealing membrane supported by the secondary insulation layer, a primary insulation layer arranged on the secondary sealing membrane and a primary sealing membrane supported by the primary insulation layer. The primary sealing membrane is responsible for defining the internal volume of the tank 2. The insulation layer is formed from an insulating block or box manufactured from plywood panels filled with insulating material.

[0041] In the remainder of this specification, the properties described with respect to the term "sealing membrane" may relate to the primary sealing membrane and / or the secondary sealing membrane, unless otherwise stated.

[0042] The sealing membrane itself comprises a number of metal strips, each having an outer surface in contact with the primary insulation layer and an inner surface facing the internal volume of the tank 2, and having folded edges. The metal strips are connected to one another via their folded edges, in other words the folded edges of two adjacent metal strips are integrated with one another, for example by welding. The fact that the metal strips are attached to one another by their folded edges promotes the elasticity of the sealing membrane, in particular when the wall of the tank 2 is subjected to thermal deformations when the liquefied gas is introduced into and / or removed from the tank 2.

[0043] Furthermore, as shown in figures 1 and 2, the tank 2 comprises an input and / or output tower 8 extending vertically between the bottom wall 4 and the top wall. The tower is adapted to input and / or output liquefied gas to the tank 2 and comprises a pumping member 10 capable of sucking the liquefied gas contained in the tank 2. The pumping member 10 is, for example, a pump capable of withdrawing the liquefied gas flowing in the sump 14 in order to supply it to a consumer, for example of the ship on which the tank 2 is installed. Such a consumer is, for example, a generator motor.

[0044] More specifically, the top wall has an opening in which a cover 12, which is part of the tank 2, is arranged, closing in a sealed manner the storage volume of the tank 2, in particular by extending the top wall at the opening. As shown in figure 2, the tower 8 at least partially crosses the cover 12, making it possible to transport liquefied gas into or out of the storage space of the tank 2.

[0045] The tank 2 further comprises at least one sump 14 in which the pumping member 10 is at least partially housed. The sump 14 is disposed through the bottom wall 4 of the tank 2 so as to allow for the suction of the liquefied gas flowing through the tank 2.

[0046] As can be seen in particular in Figure 2, the tower 8 comprises a structure that extends mainly along a main direction of extension parallel to the vertical direction V. The structure has an upper end and a lower end, the upper end facing the top wall, while the lower end facing the bottom wall 4. More specifically, the tower 8 is formed by at least three poles 16, otherwise called a tripod structure, and a base 18 advantageously placed at its lower end and uniting the three poles 16 with one another.

[0047] More specifically, the structure of the loading tower 8 comprises at least three poles 16 fixed relative to each other by a lattice structure 20, each of the three poles 16 penetrating the cover of the tank 2. The forward pole 16a of the tower 8 and the two aft poles 16b of the tower 8 are determined according to the heading of the ship visible in Figure 1 such that, under normal sailing conditions, the forward pole 16a is the pole of the tower 8 that is most forward on the tank 2.

[0048] Besides the pumping member 10, the tower 8 comprises at least one discharge member 22, 24 for the liquefied gas present in the tank 2. The discharge member 22, 24 is arranged between the front bowl 16a and one or the other of the rear poles 16b. The pumping member 10 is configured to supply fuel to at least one consumer of the structure 1. "Arranged between the front bowl 16a and one of the rear poles 16b" means that a line passing through the center of the front pole 16a and the center of said rear pole 16b passes through the discharge member 22, 24.

[0049] In this configuration, the discharge members 22, 24 are only intended to discharge liquefied gas from the tank 2, and the pumping member 10 located in the sump 14 is for return, intended to either supply fuel to at least one consumer of the structure 1 or to suck in liquefied gas in order to discharge it from the tank 2.

[0050] 3 and 4, the tower 8 includes a first discharge member 22 and a second discharge member 24. The first discharge member 22 is disposed between one of the front pole 16a and the rear pole 16b, and the second discharge member 24 is disposed between the other of the front pole 16a and the rear pole 16b. The discharge members 22, 24 are aligned with each other along a direction parallel to the lateral direction T.

[0051] According to the invention, as can be seen from figure 3, the sump 14 is arranged at least in part outside a perimeter P defined by a triangle passing through the centres of the three poles and the front pole 16a, in an angular sector defined by two axes A1, A2 each passing through the centre of the tower 8 and forming an angle α of at most 90°. The perimeter considered here is a combination of a triangle and a circle, the latter being the axial projection of the front pole 16a onto the bottom wall, the centre of which is located at the apex of the triangle.

[0052] The sump 14 is also located beyond the arc C1 centered on the center of the tower 8, said arc C1 being tangent to the rear zone of the front pole 16a of the tower 8. More specifically, the sump 14 is located in a zone 26 defined according to at least three conditions: the sump 14 must be located outside the perimeter P that combines the triangle with the projection of the front pole, the sump 14 must be located within the above-mentioned angular sector, and the sump 14 must be located beyond the arc C1 centered on the tower 8 and tangent to the rear zone of the front pole 16a.

[0053] According to one aspect of the invention, the pumping member 10 is also arranged at least partially outside the aforementioned periphery P, in an angular sector defined by two axes A1, A2 each passing through the centre of the tower 8 and forming an angle α of at most 90°, and finally beyond a circular arc C1 centred on the tower 8 and tangent to the rear zone of the front pole 16a of said tower 8. In fact, the pumping member 10 is arranged at least partially in the sump 14.

[0054] The perimeter P, defined at least in part by a triangle with its apex at the post, corresponds to the axial projection of the centers of the poles connected by the sides of the triangle, which projection can be seen in a plane perpendicular to the vertical direction V.

[0055] It should be noted that each of the poles 16 has an inner surface 28 facing the other poles 16 and an outer surface 30 facing the outside of the tower 8, the distinction between the inner surface 28 and the outer surface 30 being evaluated, for example, here with respect to the sides forming the triangle shown in Figures 3 and 4.

[0056] Because the front pole 16a is part of the exclusion perimeter, it will be appreciated that the position of the sump 14 will differ from the projection of the front pole 16a onto the angular sector, as shown by the crosses on the projection of the front pole 16a onto the angular sector in Figures 3 and 4.

[0057] The angular sector here is defined by two axes A1, A2 passing through the centre of the tower 8, i.e. through the centre of a circle passing through the centres of the three poles 16 of the tower 8. In other words, the two axes A1, A2 intersect each other at the centre of the tower 8. These two axes A1, A2 form an angle of at most 90° and are involved in at least partially laterally defining a zone 26 in which the sump 14 and the pumping member are arranged.

[0058] Advantageously, each of the axes A1, A2 passes through one of the discharge members 22, 24 of the tower 8. For example, as shown diagrammatically in Figures 3 and 4, each of the axes A1, A2 passes through the periphery of the discharge members 22, 24.

[0059] Also, the angle of the angular sector is open at the front pole 16a, in other words the front pole 16a is flanked in the transverse direction with respect to the axes A1, A2 that define the angular sector.

[0060] As shown in Figure 3, one of the axes A1, A2 participating in defining an angular sector intersects with an axis passing through the centre of the tower 8 and the centre of the front pole 16a to form an angle of between 40° and 50°. Advantageously, this angle is 45°.

[0061] More advantageously, each of the axes A1, A2 contributing to define an angular sector intersects with an axis passing through the centres of the two rear posts 16b to form an angle of between 40° and 50° each.

[0062] The angular sector comprises two angular sub-sectors symmetrical with respect to an axis passing through the centre of the tower 8 and the centre of the front pole 16a. This vertical axis also corresponds to the longitudinal axis of the tank.

[0063] Finally, with regard to the arc C1, this is inscribed in a circle centered on the center of the tower 8, i.e. the center of a circle passing through the center of each of the poles 16 of the tower 8, and constitutes the minimum limit of the zone 26 in which the sump 14 is located. It will be understood that the position of the sump 14 in the zone 26 is located beyond this arc C1, in front of the tank 2.

[0064] As can be seen from Figures 3 and 4, the arc C1 is tangent to the rear zone of the forward pole 16a of the tower 8, i.e. to the zone of the forward pole 16a located inside the triangle participating in forming the perimeter P. Advantageously, the arc C1 passes through the inner surface 28 of the forward pole 16a. It will be understood that the sump 14 can be located, for example, forward of the forward pole 16a or generally aligned laterally to the forward pole 16a at any position within the zone 26.

[0065] The radius of the arc C1 is at least 1600 mm, 1650 mm or 1700 mm, this dimension being measured in a plane horizontal to the vertical direction V, between the centre of the tower 8 and here the inner surface 28 of the front pole 16a.

[0066] According to the invention, the zone 26 in which the sump 14 is arranged is defined longitudinally by the above-mentioned arc C1, which is a first arc C1, and by a second arc C2, so that the zone 26 extends between the first arc C1 and the second arc C2 and between the axes A1 and A2 which border an angular sector according to the invention.

[0067] More precisely, the first arc C1 corresponds to the smallest arc and the second arc C2 corresponds to the largest arc. Like the first arc C1, the second arc C2 is centred on the centre of the tower 8 and has a radius equal to 3400 mm at most, advantageously between 3200 mm and 3400 mm at most. Advantageously, the second arc C2 has a radius of 3300 mm.

[0068] From the above it will therefore be seen that the invention 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 laterally by axes A1, A2 defining an angular sector, and longitudinally by at least a first circular arc C1 and advantageously by a second circular arc C2, excluding the interior of the periphery formed by the periphery P of the tower 8.

[0069] Two exemplary embodiments of the present invention will now be described, which differ in the location of the sump 14 in the zone 26. A first embodiment of the present invention will first be described with reference to Figure 3, and a second embodiment of the present invention will be described after the description of the first embodiment with reference to Figure 4.

[0070] As shown in FIG. 3, an axis 34 passing through the center of the tower 8 and the center of the front pole 16a passes through the sump 14. The axis 34 is substantially parallel to the longitudinal direction L. In other words, the centers of the sump 14, the front pole 16a, and the tower 8 are aligned with respect to each other. It will be appreciated that in this arrangement, the sump 14 is sufficiently spaced from the tower 8 so as to limit the stiffness of the bottom wall 4 of the tank 2 required for its arrangement. The pumping member 10 is also aligned with the center of the front pole 16a and the tower 8. This allows for easy installation, fitting, and / or maintenance of the pumping member 10 in the tank 2.

[0071] As shown in FIG. 4, the tower 8 is equipped with a system 36 for conveying liquefied gas from the tank 2. The projection of the conveying system 36 on the bottom wall 4 is arranged in the zone 26. The position of the sump 14 in the zone 26 is different from the projection of the conveying system 36. "Different" means that the position of the sump 14 and the projection of the conveying system 36 do not overlap, i.e. the sump 14 is not arranged below the conveying system 36. The different arrangement of the position of the sump 14 and the projection of the conveying system 36 makes it possible to avoid that the liquefied gas is sprayed directly into the sump 14 and thus at least partially onto the pumping element 10 during conveying of the liquefied gas from the tank 2. Moreover, the overlap of the conveying system 36 and the sump 14 can complicate the installation and mounting of the tower 8 in the tank 2.

[0072] 4, the angular sector is separated into a first subsector and a second subsector by an axis 34 passing through the center of the tower 8 and the front pole 16a. The projection of the delivery system 36 is located in the first subsector, while the sump 14 is located in the second subsector. In other words, the position of the sump 14 and the projection of the delivery system 36 laterally frame the front pole 16a.

[0073] Advantageously, a straight line passing through the centre of the projection of the input system 36 and the centre of the front pole 16a also passes through the sump 14. More precisely, this straight line passes through the sump 14, but does not necessarily pass through its centre.

[0074] However, the present invention is not limited to the means and configurations described and illustrated herein, but covers equivalent means or configurations and any technical combinations using such means. In particular, the description of the position of the sump 14 in the first and second embodiments does not limit the present invention. These examples are merely illustrative of embodiments of the present invention. Thus, by way of reminder, the present invention relates to the sump 14 being located in a zone 26 defined at least by an angular sector defined by two axes A1, A2, the periphery P of the tower 8, and optionally by a circular arc C1.

Claims

1. A tank (2) intended for a structure (1) and configured to contain liquefied gas, The tank (2) comprises a bottom wall (4), a top wall, and a plurality of side walls (6) extending between the bottom wall (4) and the top wall; The tank (2) comprises at least one loading and / or unloading tower (8) extending vertically between the bottom wall (4) and the top wall, The tower (8) comprises a base (18) and at least three poles (16, 16a, 16b) fixed to the base (18); Two poles (16) form rear poles (16b) and the third pole (16) forms the front pole (16a); The tower (8) comprises at least one pumping member (10) for the liquefied gas and a sump (14) extending through the bottom wall (4) and in which the pumping member (10) is at least partially disposed. In the tank (2), the sump (14) is at least partially located outside a perimeter (P) defined by a triangle whose vertices are centered on the poles (16, 16a, 16b) and pass through the edge of the front pole (16a); the sump (14) is arranged in an angular sector defined by two axes (A1, A2) each passing through the center of the tower (8) and forming an angle (α) of at most 90°; A tank (2) characterized in that

2. The sump (14) is disposed beyond an arc (C1) centered on the center of the tower (8); The arc (C1) is tangent to the rear zone of the front pole (16a) of the tower (8), A tank (2) according to claim 1.

3. the tower (8) comprises at least one member (22, 24) for conveying liquefied gas, the member (22, 24) being arranged between one or the other of the front pole (16a) and the rear pole (16b); A tank (2) according to claim 1 or 2.

4. one of the axes (A1, A2) participating in the definition of the angular sector intersects with an axis passing through the center of the tower (8) and the center of the front pole (16a) to form an angle of between 40° and 50°; A tank (2) according to claim 1 or 2.

5. The radius of said circular arc (C1) is at least equal to 1600 mm; A tank (2) according to claim 2.

6. The arc (C1) is the smallest arc, the sump (14) is disposed between the minimum circular arc (C1) and a maximum circular arc (C2) centered on the center of the tower (8), the radius of the maximum circular arc (C2) being at most equal to 3400 mm; A tank (2) according to claim 2 or 5.

7. The tower (8) comprises a system (36) for transferring liquefied gas from the tank (2), the projection of said delivery system (36) onto said bottom wall (4) lies within said angular sector; the position of the sump (14) within the angular sector is different from the projection of the delivery system (36); A tank (2) according to claim 1 or 2.

8. 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 pole (16a); A tank (2) according to claim 1 or 2.

9. The tower (8) is provided with a system (36) for transporting liquefied gas from the tank (2), the projection of said delivery system (36) onto said bottom wall (4) lies within said angular sector; the position of the sump (14) within the angular sector differs from the projection of the delivery system (36); the projection of the delivery system (36) onto the bottom wall (4) is located in the first sub-sector, while the sump (14) is located in the second sub-sector; A tank (2) according to claim 8.

10. The tower (8) is provided with a system (36) for transporting liquefied gas from the tank (2), the projection of said delivery system (36) onto said bottom wall (4) lies within said angular sector; the position of the sump (14) within the angular sector differs from the projection of the delivery system (36); the sump (14) and the projection of the delivery system (36) onto the bottom wall (4) are located in the same subsector; A tank (2) according to claim 8.

11. An axis (34) passing through the center of the tower (8) and the center of the front pole (16a) passes through the sump (14). A tank (2) according to claim 1 or 2.

12. At least the bottom wall (4) of the tank (2) comprises at least one insulating layer and a sealing membrane supported by the insulating layer; The sealing membrane is involved in defining the internal volume of the tank (2), the sealing membrane comprising a plurality of metal strips having raised edges, the metal strips being connected to one another by the raised edges; A tank (2) according to claim 1 or 2.

13. A structure (1) comprising a tank (2) according to claim 1 or 2, the structure (1) being selected from a liquefied gas carrier, a barge, a reliquefaction unit, a gasification unit, a gravity platform or a land-based structure.

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