Method for assembling and installing a liquefied gas storage tank

Abstract

The present invention relates to a liquefied gas storage device, the liquefied gas storage device comprising a load-bearing structure and a sealed and thermally insulated tank (71), the sealed and thermally insulated tank being arranged in the load-bearing structure, wherein a so-called adjacent film (13, 13') in a sealing film of an enclosing wall of a main structure of the tank (71) projects at least partially into a liquid dome (2), and the so-called adjacent film can be directly and sealingly fixed to a so-called adjacent film of the liquid dome (2).

Description

Field of the Invention

[0001] The present invention relates to the field of liquefied gas storage equipment, which includes a sealed and thermally insulated membrane tank. In particular, the present invention relates to the field of sealed and thermally insulated tanks for storing and / or transporting liquefied gas at low temperatures, such as tanks for transporting liquefied petroleum gas (also known as GPL, Gaz de Pétrole Liquéfié) at a temperature between -50°C and 0°C, or tanks for transporting liquefied natural gas (GNL, Gaz Naturel Liquéfié) at approximately -162°C under atmospheric pressure. These tanks can be installed onshore or on floating structures. In the case of floating structures, the tanks can be used to transport liquefied gas or to receive liquefied gas used as fuel to propel the floating structure. Background Art

[0002] FR2991430 describes a liquefied gas storage equipment that includes a sealed and thermally insulated storage tank incorporated into a load-bearing structure formed by the double hull of a ship. Each wall of the tank includes a secondary thermal insulation shield, a secondary sealing membrane, a primary thermal insulation shield, and a metallic primary sealing membrane or a metallic alloy primary sealing membrane.

[0003] The primary sealing membrane generally includes pleats suitable for allowing thermal shrinkage so that the membrane does not fail. These pleats generally form a network of small pleats and large pleats extending parallel to each other, thus forming a grid defined by nodal regions (i.e., the substantially perpendicular intersections of the small pleats and the large pleats).

[0004] In the region located at the top of the tank, the tank includes a chimney-shaped protruding portion. In this region, the load-bearing structure is locally interrupted to define a loading / unloading opening through which a fluid loading / unloading pipe can pass. This loading / unloading opening and this chimney-shaped pipe called the liquid dome include a thermal insulation portion or a thermal insulation shield, and elements forming the primary sealing membrane.

[0005] In the append Figure 1 and append Figure 2 It can be seen that the liquid dome is generally located at one longitudinal end of the tank, such that one of the vertical walls of the liquid dome is continued or extended in the same plane by the vertical wall of the main structure (containing the cold fluid) of the tank. When the tank is present in a ship (i.e., a Liquid Natural Gas Carrier, LNGC) for transporting cold fluids (such as GNL or GPL), the vertical wall shared by the liquid dome and the main structure of the tank is called the enclosure wall.

[0006] The tank is installed in a structure (such as a ship) that is subjected to very high mechanical stresses, and the structure bends and twists according to the environmental conditions of the structure. These mechanical stresses are even greater at the point where the load-bearing structure is interrupted at the liquid dome.

[0007] The walls of the main structure of the tank are installed and assembled / fixed, and the walls of the liquid dome are installed and assembled / fixed separately, so that these two parts of the storage device are connected to each other in a sealed manner.

[0008] Particularly due to the size of the main insulation film, the film is connected and the continuity of the pleats is provided by a connecting plate that generally has a small size, and the connecting plate is fixed to the adjacent films of the liquid dome and the main structure of the tank by welding.

[0009] This connecting plate is not a satisfactory solution.

[0010] First, due to the misalignment of the pleats of the two parts (the liquid dome on the one hand and the main structure on the other hand), in order to ensure the continuity of the vertical pleats between the liquid dome and the main structure of the tank, the operator must use a knocking tool to deform the connecting plate in place. This operation is arduous for the operator and usually requires several hours of work.

[0011] In addition, the shape of the connecting plate at the vertical pleats of the connecting plate makes the connecting plate fragile. As mentioned above, this area of the ship is subject to high mechanical stresses. This is why the part where the main sealing film may fail and damage the seal of the storage device is unacceptable. Summary of the Invention

[0012] After various experiments and tests, the applicant has found that by proposing an assembly solution as follows, the connecting part or the plate-like part can be omitted, the assembly solution is simpler and faster, and at the same time, the connection area between the main film of the main structure of the tank and the main film of the liquid dome can be made more reliable in terms of mechanical strength and sealing.

[0013] Therefore, the present invention relates to a liquefied gas storage device, which includes a load-bearing structure and a sealed and insulated tank, and the sealed and insulated tank is arranged in the load-bearing structure.

[0014] The sealed and insulated tank includes a main structure formed by a plurality of tank walls, the plurality of tank walls are connected to each other and fixed to the load-bearing structure, the main structure defines an internal storage space, the main structure includes at least one sealing film and at least one heat insulation shield, and the heat insulation shield is arranged between the sealing film and the load-bearing structure.

[0015] The sealing film, heat-insulating shielding part of the main structure, and a so-called upper load-bearing wall are partially interrupted to define a duct that forms the load-bearing wall of the chimney part. The chimney part extends along a vertical axis to an upper end part that includes a loading / unloading opening through which a liquefied gas loading / unloading pipe can pass. The duct leading to the opening defines the liquid dome of the tank, and the liquid dome, similar to the main structure of the tank, includes at least one sealing film and at least one heat-insulating shielding part, and the heat-insulating shielding part is arranged between the sealing film and the load-bearing wall;

[0016] The liquid dome is located at an axial end of the tank, and a vertical wall called an enclosing wall of the main structure of the tank extends from the main structure to form the wall of the duct of the liquid dome along the same plane;

[0017] The sealing film of the main structure and the sealing film of the liquid dome are composed of a plurality of flat metal films that can be hermetically fixed together. Each metal film has at least two rows of vertical corrugations, and the shapes and sizes of these two rows of corrugations are the same for all the films, so that these juxtaposed films show a repeating pattern;

[0018] The present invention is characterized in that the so-called adjacent films in the sealing film of the enclosing wall of the main structure of the tank at least partially project into the liquid dome, and the so-called adjacent films can be directly hermetically fixed to the so-called adjacent films of the liquid dome.

[0019] Therefore, the applicant has observed after multiple tests and analyses that, without using a connecting plate, the main structure of the tank can be firmly and completely sealed to the liquid dome while optimizing the installation or assembly time of the corresponding films of these two components of the liquefied gas storage device.

[0020] By doing so, the present invention enables significant savings to be achieved in the manufacture of the liquid dome while ensuring or maintaining a complete seal for the liquefied gas and excellent mechanical resilience of the liquid dome to all the stresses that the liquid dome usually undergoes.

[0021] The expression "hermetically" used with respect to the fixing (especially the fixing between films) is used to indicate that the fixing is carried out by welding, optionally supplemented by chemical fixing, adhesive bonding, and / or mechanical fixing (such as using seals).

[0022] The term "metal" (especially the metal related to the film) refers to a metal or a metal alloy, usually a metal alloy, such as steel.

[0023] Whether or not the term "membrane" appears with the term "sealed", the term "membrane" systematically refers to a fluid-impermeable sealed membrane. If the membrane has at least one row of vertical pleats, preferably a plurality of vertical pleats, and at least one row of horizontal pleats on the enclosing wall, the membrane is classified as a membrane within the scope of the present invention. In the embodiment selected for illustrating the present invention, the vertical pleats on the enclosing wall are small pleats, while the horizontal pleats are large pleats.

[0024] The term "pleat", in its singular or plural form, refers to an element present on the membrane such that the membrane can deform by contraction and / or stretching under the thermal expansion effects associated with the presence or absence of cold or very cold liquefied gas in the tank. Within the scope of the present invention, the two rows of vertical pleats defining the membrane can be of the same or different shapes. Hereinafter, the two rows of pleats are advantageously different and have a horizontal row of large pleats and a vertical row of small pleats.

[0025] The term "adjacent" (mainly with respect to the membranes of the liquid dome of the tank and the main structure) means that these membranes are closest to the other parts of the tank, i.e., for the membrane located in the liquid dome, it means closest to the main structure, and for the membrane located in the main structure, it means closest to the liquid dome.

[0026] The term "duct" means that the duct forms the outer wall of the liquid dome, and more specifically, forms the wall of the chimney portion leading into the tank containing the liquefied gas. The term "chimney portion" means the general shape of the liquid dome extending vertically.

[0027] The following briefly lists other advantageous features of the present invention:

[0028] Preferably, the flat metal membrane has a rectangular shape with two long sides and two short sides, and the flat metal membrane forms the sealed membrane of the main structure and the liquid dome.

[0029] Preferably, the flat metal membrane includes a raised portion extending along two adjacent sides, and the raised portion is adapted to overlap with the adjacent sides of another membrane.

[0030] Advantageously, the thermal shielding portions of the main structure of the tank and the liquid dome include metal plates, and the sealed membranes of the main structure and the liquid dome are discontinuously welded to the metal plates.

[0031] Advantageously, the so-called adjacent membrane of the liquid dome includes a raised portion extending along the lower long side, while the so-called directly adjacent membrane of the main structure of the tank includes a raised portion extending along one of the two short sides of the membrane. According to a specific example, the so-called directly adjacent membrane of the main structure of the tank includes only one raised portion extending along one of the two short sides of the membrane.

[0032] According to a particular embodiment, when these so-called adjacent membranes are installed and assembled after the other membranes of the liquid dome (which is a preferred embodiment of the present invention), the so-called adjacent membranes of the liquid dome include raised portions extending along two opposite long sides, while the so-called directly adjacent membranes of the main structure of the tank include only one raised portion extending along one of the two short sides of the membrane respectively.

[0033] According to a particular feature of the present invention, the protruding portions of the so-called adjacent membranes in the sealing membrane of the enclosing wall (B) of the main structure of the tank preferably protrude into the liquid dome by at least 30 mm, preferably 55 mm.

[0034] According to a particular feature of the present invention, the protruding portions of the so-called adjacent membranes in the sealing membrane of the enclosing wall (B) of the main structure of the tank protrude into the liquid dome by at most 60 mm.

[0035] Here, it should be noted that the expression "enclosing wall" (i.e., the wall identified as B or B' in Figure 2 )(especially the enclosing wall with respect to the main structure of the tank) is not necessary, because in the embodiments selected to illustrate the present invention, the membranes related to the present invention are the membranes of the enclosing wall, because this wall is the only wall that extends vertically (in other words, without changing the angle) into the liquid dome.

[0036] Of course, if, for example, the liquid dome is in the corner of the main structure, the present invention will also be applicable, such that in addition to the enclosing wall, the side wall - if there is no chamfer E, Figure 2 the wall F in

[0037] will extend vertically into the liquid dome. Even though this arrangement of the liquid dome in the corner of the tank is theoretically disadvantageous and impractical, the present invention covers such a situation.

[0038] Advantageously, the length of the so-called adjacent membranes of the liquid dome is between 500 mm and 3300 mm, and the width of the so-called adjacent membranes is between 200 mm and 800 mm.

[0039] According to another advantageous aspect of the present invention, the so-called adjacent membranes in the sealing membrane of the enclosing wall of the main structure of the tank are in two rows of parallel membranes, the width of one row of membranes is between 200 mm and 400 mm, and the width of the other row of membranes is between 700 mm and 800 mm.

[0040] The present invention also relates to a method for assembling a storage device as described above, wherein the method includes:

[0041] - The first step of sealingly assembling and fixing a sealing film assembly to an enclosing wall of the main structure of the tank;

[0042] - The second step of sealingly assembling and fixing a sealing film assembly of the liquid dome other than the adjacent film of the liquid dome;

[0043] The first step and the second step are performed in any order or simultaneously;

[0044] - And the final step of sealingly assembling and fixing the so-called adjacent film of the liquid dome such that the assemblies of the enclosing walls of the main structure and of the liquid dome are sealed.

[0045] The present invention relates to a ship for transporting cryogenic liquid products, the ship comprising a double hull and a storage device as described above disposed within the double hull.

[0046] The present invention also relates to a system for transporting cryogenic liquid products, the system comprising a ship as described above, a heat-insulated pipe, and a pump, the heat-insulated pipe being arranged such that the heat-insulated pipe connects a tank installed in the hull of the ship to a floating or onshore external storage device, and the pump being configured to convey a flow of cryogenic liquid products through the heat-insulated pipe from the floating or onshore external storage device to the tank of the ship, or from the tank of the ship to the floating or onshore external storage device.

[0047] Finally, the present invention relates to a method for loading or unloading a ship as described above, wherein cryogenic liquid products are conveyed through the heat-insulated pipe from a floating or onshore external storage device to the tank of the ship, or from the tank of the ship to a floating or onshore external storage device. Description of the Drawings

[0048] The present invention will be more clearly understood and other objects, details, features and advantages of the present invention will become apparent from the following description of several specific embodiments of the present invention given by way of non-limiting illustration and with reference to the drawings.

[0049] Figure 1 Figure 1 is a schematic perspective cross-sectional view of a liquefied gas carrier or LNGC.

[0050] Figure 2 Figure 2 is in Figure 1 a cross-sectional view of the tank of the ship shown in.

[0051] Figure 3 Figure 3 is a schematic view showing a sealing film having three parallel rows of large pleats and nine parallel rows of small pleats, the two types of rows being perpendicular to each other.

[0052] ​​​​​​Figure 4 Figure 4 shows the arrangement of the membranes in the region of the liquid dome of the tank and in the region of the main structure, and shows the overlap of each membrane with respect to its adjacent parts.

[0053] Figure 5 Figure 5 is Figure 4 an enlarged view of part P in

[0054] Figure 6 Figure 6 is a detailed view of the dimensions of adjacent membranes (referred to as side membranes) of the main structure of the tank.

[0055] Figure 7 Figure 7 is Figure 4 the same view as the view in

[0056] Figure 8 Figure 8 shows a cross-sectional view of a methane transportation vehicle storage device and a terminal for loading / unloading the tank. DETAILED DESCRIPTION

[0057] Herein, the term "vertical" means extending in the direction of the earth's gravitational field. Herein, the term "horizontal" means extending in a direction perpendicular to the vertical direction.

[0058] When the storage device is arranged on a ship 70 such as a methane transportation vehicle, the load-bearing structure (not visible in the drawings) is formed by the double hull of the ship. The outer upper load-bearing wall is called the outer deck of the ship.

[0059] Hereinafter, the present invention is shown with a conventional liquefied gas transportation vehicle 70 (i.e., a liquid natural gas carrier, LNGC), but the present invention can of course be applied to other types of tanks as long as such tanks include a sealing membrane (which is called the main sealing membrane because it is in direct contact with the fluid contained in the tank, and optionally a secondary sealing membrane) and a liquid dome 2 or the like, that is, having at least one wall surface continuing from the wall of the main structure of the tanks 71, 71' and an opening and a chimney part for loading / unloading the fluid. If these two features are confirmed, the present invention can be applied to such fluid storage devices.

[0060] Therefore, Figure 1 ​​​​​​​​​​Shows the distribution of four GNL tanks 71, 71' that are normally present in the LNGC 70. Considering that when the tank 71 is empty, most of the weight of the ship 70 is located behind this tank. Therefore, as observed above, three of the four tanks 71 have the same size, while the last tank 71' located at the bow of the ship 70 has a smaller size. In particular, the size of the ballast arranged horizontally and below the tank 71' is much larger than the size of the other ballast arranged around the other three tanks 71, in order to more easily balance the load balance of the ship 70.

[0061] Machines or machine rooms (from the propulsion unit to all circuits for generating and supplying electricity to various types of equipment on the ship 70) that are not visible in the drawings and are used to manage the entire ship 70 are usually located at the stern of the ship 70. In addition, above the machines is the bridge section 31, which usually includes a tower section or the like, and the crew's quarters and the control room of the ship are particularly located in the bridge section.

[0062] The tank 71 includes a main structure composed of a front wall D, a rear wall B, a top wall A, a bottom wall C, two side walls F, and two to four chamfered walls E, G. The two side walls are not both visible in the attachment Figure 2 (because one side of the tank is not visible in this figure). The two side walls connect the bottom wall C to the top wall A, and the two to four chamfered walls connect the side walls F to the bottom wall C or the top wall A. Therefore, the walls of the tank 71 are connected to each other to form a polyhedral structure and define an internal storage space. The tank 71' is substantially the same as the tank 71.

[0063] In order to load liquefied gas into the tank 71 and unload it from the tank 71, the storage device 1 includes a loading / unloading opening that locally interrupts the outer upper load-bearing wall, the inner upper load-bearing wall, and the top wall of the tank 71, so as to particularly enable a loading / unloading pipe (not shown in the drawings) to reach the bottom of the tank 71 by passing through this opening.

[0064] The storage device also includes a loading / unloading tower section (not visible in the drawings), which is aligned with the opening of the liquid dome 2 and is inside the tank 71, forming a support structure for the loading / unloading pipe throughout the height of the tank 71 and for a pump (not shown).

[0065] Therefore, the tank 71 includes a chimney section or a pipe, which is located on or above the main structure and enables the tank wall to continuously extend from the inner deck to the outer deck, and the tank wall is interrupted by the loading / unloading opening at the outer deck. For the liquefied gas storage tanks 71, 71', such a chimney section or a pipe is called a liquid dome 2, and such a chimney section or a pipe is provided with a cover for closing the loading / unloading opening.

[0066] The loading / unloading opening and the chimney part usually have a rectangular or square profile or action. Thus, the chimney part includes four walls, one wall B’ being an extension of the rear wall B and also being referred to as the “enclosing wall” of the main structure of the tanks 71, 71’, as can be seen in Figure 2 while the other three walls are connected to the top wall A and form a 90° angle with the top wall.

[0067] The present invention relates only to the walls B, B’ or, in different embodiments, to two walls which are continuous or extended and which do not change the angle between the main structure of the tanks 71, 71’ and the liquid dome 2. More specifically, the present invention relates to the sealing membrane and to the joint between the sealing membrane and the main structure of the tanks 71, 71’ and the liquid dome 2.

[0068] Figure 3 Such a conventional sealing membrane 3 is shown. Within the scope of the present invention, the sealing membrane is defined as a metal sheet or metal alloy sheet including at least a first row of corrugations 4 and at least a second row of corrugations 5, the first row of corrugations 4 and the second row of corrugations 5 extending perpendicular to each other.

[0069] According to one embodiment, the main structure of the tanks 71, 71’ is manufactured using the Mark technique, which is specifically described in the document FR-A-2691520. technique.

[0070] In such a main structure, the secondary thermal shielding, the primary thermal shielding and the secondary sealing membrane mainly comprise panels juxtaposed on a load-bearing structure, which may be an internal load-bearing structure or a structure connecting an internal upper load-bearing wall to an external upper load-bearing wall at the opening. The secondary sealing membrane is made of a composite material and includes an aluminum sheet sandwiched between two fiberglass fabric sheets. The primary sealing membrane is obtained by assembling a plurality of metal sheets which are welded to each other along the edges of the metal sheets and which include corrugations extending in two perpendicular directions. The metal sheets are made, for example, of stainless steel or aluminum and are shaped by bending or stamping.

[0071] More particularly, to illustrate an embodiment of the present invention, according to the membrane shown in Figure 3 the sealing membrane is the so-called primary sealing membrane obtained by assembling a plurality of corrugated metal sheets (since this sealing membrane is in direct contact with the fluid stored in the tanks 71, 71’). Each corrugated metal membrane 3 includes a first series of so-called high or large parallel corrugations 5 extending in a first direction, and a second series of so-called low or small parallel corrugations 4 extending in a second direction perpendicular to the first series. The node region 6 is the region where these two types of corrugations 4, 5 intersect. The corrugations 4, 5 project towards the inside of the tanks 71, 71’. As mentioned above, these corrugated metal membranes 3 are made, for example, of stainless steel or aluminum.

[0072] The corrugated metal film 3 is fixed to the heat insulation plate 21 by metal plates 20 extending vertically and horizontally in two perpendicular directions on the enclosing walls B, B', and these plates 20 are fixed to the inner surface of the heat insulation plate 21 (oriented towards the inner space of the tank). Thus, each heat insulation plate 21 has an inner surface on which the metal plates 20 are arranged, and the corrugated metal film 3 forming the main sealing film is welded to the metal plates. In the attachment Figure 7 shown, these heat insulation plates 21 can be seen, and the sealing film 3 together with the aforementioned metal plates 20 is fixed to the heat insulation plate.

[0073] The metal plates 20 extend in two perpendicular directions, each of which is parallel to two opposite edges of the heat insulation plate 21 respectively. The metal plates 20 are fixed in grooves and are fixed to the grooves using, for example, screws, rivets or clips, and the grooves are formed in the inner surface of the heat insulation plate 21.

[0074] Attachment Figure 4 to attachment Figure 7 shows the actual arrangement of the sealing film 3 or the main sealing film on the wall B of the main structure of the tanks 71, 71' and on the wall B' extending from the wall B in the liquid dome 2.

[0075] The first feature of this arrangement is that only the sealing films 3, 13, 13', 33 are used to ensure the sealing continuity between these two walls (the enclosing wall B of the main structure of the tanks 71, 71' and the wall B' extending from the wall B of the liquid dome 2), and the sealing films include at least two rows 4, 5 of corrugated portions perpendicular to each other. Thus, there are no intermediate elements in this area, and it should be understood that an "intermediate element" such as a metal plate is not the sealing film 3, 13, 13', 33 according to the present invention, that is, not the film defined as above.

[0076] The second feature of this arrangement according to the present invention is that the protrusions of the sealing film 13 of the main structure of the tanks 71, 71' are directly adjacent to the liquid dome 2, that is, in Figure 4 the three films 14, 15, 16 visible protrude into the liquid dome 2, that is, protrude from the opening existing in the top wall A into the space forming the liquid dome 2, and here heat insulation and sealing elements are considered to define the position of this opening of the liquid dome 2.

[0077] In Figure 6 it can be seen that in this example, the protrusion 17 of the sealing film 13 protruding into the liquid dome 2 is 55 mm. Generally, this protrusion 17 is at least 30 mm and at most 60 mm. As in Figure 6As can be clearly seen, in order to form the protrusion 17, the adjacent membranes 13 protrude over their entire width (as is the case with the central membrane 15), or the adjacent membranes only protrude over a part of their width (as is the case with the side membranes 14 and 16). For these so-called side membranes 14 and 16, incisions are made in the conventional membrane using, for example, a laser or a saw to remove the part that is adjacent to the liquid dome 2 and thus does not protrude into the liquid dome 2.

[0078] Another specific feature of the invention lies in the dimensions of the adjacent membranes 13, 13', 33 of both the liquid dome 2 and the main structure of the tanks 71, 71'. These dimensions are not conventional and have been chosen such that the connection between the membranes 13, 13' of the main structure of the tanks 71, 71' and the membrane 33 of the liquid dome 2 fits perfectly and as firmly as possible. Thus, the conventional membrane 3 of the main structure of the tanks 71, 71' usually includes three rows of 5 large pleats, while the adjacent membranes 13, 13' of the main structure of the tanks 71, 71' only include two rows of 5 large pleats for the directly adjacent membrane 13, or even a single row / only row of 5 large pleats for the adjacent membrane 13'. Similarly, the conventional membrane 3 of the liquid dome 2 usually includes two rows of 5 large pleats, while the adjacent membrane 33 of the liquid dome 2 only includes a single row / only row of 5 large pleats.

[0079] By way of non-limiting example, Figure 6 shows the dimensions (in millimeters) of the adjacent side membrane 14 of the main structure of the tanks 71, 71', which particularly has a protrusion 17 of 55 millimeters formed by a pre-cut made in the membrane 14. Figure 4 and Figure 5 shows, to scale, the membranes 13, 13' and 33, a part of the main structure of the tanks 71, 71', and the liquid dome 2, and the dimensions (or rather, the regions or ranges of the dimensions) of each of the membranes 13, 13' and 33 can be deduced using the knowledge of the dimensions precisely given for the adjacent side membrane 14 in Figure 6 Of course, it should be noted here that Figure 6 the precise dimensions given in Figure 6 only represent one embodiment, and other embodiments of the invention can be envisaged, and the dimensions given in

[0080] Another specific feature of the present invention is that adjacent membranes 33 of the liquid dome 2 have raised portions 7 on two lower / upper surfaces 34, 35 or two opposite long sides of the membrane, which raised portions extend along said two surfaces or sides 34, 35 so as to overlap with two lower and upper membranes, and said two surfaces or sides are fixed to the upper and lower membranes respectively. It should be noted here that within the scope of the present invention, only the lower raised portion 7 is necessary. In the present invention, the adjacent membranes 33 of the liquid dome must be installed and assembled after the membranes of the main structure of the tanks 71, 71'.

[0081] This specific feature of these adjacent membranes 33 is demonstrated by the assembly method peculiar to the storage device according to the present invention. In the present invention, once the sealing membranes of the liquid dome 2 have been assembled and fixed, and the sealing membranes of the main structure of the tanks 71, 71' (or at least the membranes near the liquid dome 2) have also been assembled and fixed, these adjacent membranes 33 of the liquid dome 2 are advantageously assembled last. Thus, the directly adjacent membranes 13 of the main structure of the tanks 71, 71' have only a single raised portion 7, more specifically a single raised portion on one of the short sides (width).

[0082] It should be noted that, as shown in Figure 3 the conventional membrane 3 has two raised portions 7 extending along two adjacent sides of the membrane 3 (i.e., one of the short sides defining the width of the membrane 3 and one of the long sides of the membrane 3). As will be noted in Figures 4 to 6 by the orientation of the tip of the black isosceles triangle, said triangle indicates the position of the raised portion 7 such that the membrane on which the black isosceles triangle is located overlaps with the adjacent membrane along this raised portion 7 on the short side or long side in question. In particular, Figure 4 very clearly shows the relative installation or assembly of different membranes, whether the membranes are the membranes 3, 33 of the liquid dome 2 or the membranes 3, 13, 13' of the main structure of the tanks 71, 71'.

[0083] Figure 7The insulating block part 21 provided on the liquefied gas storage device is shown. Within the scope of the present invention, these insulating block parts 21 have not been modified with respect to the prior art, and the details of such insulating block parts 21 are described in particular in FR-A-2861060. However, the specific feature of the present invention lies in the metal plates 20 as described above provided on these insulating block parts 21, the metal plates facing the membranes 3, 13, 13', 33 to fix the membranes 3, 13, 13', 33 to the insulating block parts 21 by welding or bonding with these metal plates 20. Here, for the adjacent membranes 13, 13' and 33 of the main structure of the tanks 71, 71' and the membranes 13, 13' and the membrane 33 of the liquid dome 2, these metal plates 20 (also referred to as anchoring strips (AS)) are arranged in a suitable manner.

[0084] Thus, the adjacent membranes 33 of the liquid dome 2 are positioned adjacent to the metal plates 20 such that when these membranes 33 are not wide due to having only one row of 5 large corrugated parts, these membranes have a discontinuous welding line extending over more than 70% of the length of the membrane. In contrast, the other membranes 3 of the liquid dome 2 have two rows of 5 large corrugated parts and have only one discontinuous welding line on the plate 20, representing more than 70% of the length of the membrane. When the small adjacent membranes 13' of the main structure of the tanks 71, 71' also have only a single / unique row of 5 large corrugated parts like the membrane 33, the small adjacent membranes 13' are also provided with such a discontinuous welding line.

[0085] Refer to Figure 8 , a cross-sectional view of the methane carrier 70 shows a sealed and insulated tank 71 having a generally prismatic shape assembled in the double hull 72 of the ship. The wall of the tank 71 includes: a main sealing membrane adapted to contact the GNL contained in the tank; a secondary sealing membrane arranged between the main sealing membrane and the double hull 72 of the ship; and two heat insulating shielding parts respectively arranged between the main sealing membrane and the secondary sealing membrane, and between the secondary sealing membrane and the double hull 72.

[0086] In a manner known per se, the loading / unloading pipe 73 arranged on the upper deck of the ship can be connected to a marine terminal or a port terminal through a suitable connector to transfer or transfer the GNL cargo from the tank 71 to the tank 71.

[0087] Figure 8An example of a marine terminal is shown, which includes a loading and unloading station 75, a subsea pipeline 76, and onshore equipment 77. The loading and unloading station 75 is a fixed offshore facility including a movable arm 74 and a tower 78 that supports the movable arm 74. The movable arm 74 supports a bundle of thermally insulated flexible pipes 79, which can be connected to the loading / unloading pipe 73. The orientable movable arm 74 is suitable for methane carriers of all sizes. Connecting pipelines (not shown) extend within the tower 78. The loading and unloading station 75 enables the loading of the methane carrier 70 from the onshore equipment 77 and the unloading of the methane carrier to the onshore equipment. The onshore equipment includes a liquefied gas storage tank 80 and a connecting pipeline 81, which is connected to the loading or unloading station 75 through the subsea pipeline 76. The subsea pipeline 76 enables the transportation of liquefied gas over a long distance (e.g., 5 km) between the loading or unloading station 75 and the onshore equipment 77, and this enables the methane carrier 70 to be kept at a long distance from the coast during the loading and unloading operations.

[0088] To generate the pressure required for transporting the liquefied gas, pumps on the ship 70, and / or pumps provided at the onshore equipment 77, and / or pumps provided at the loading and unloading station 75 are implemented.

[0089] Although the present invention has been described with reference to a plurality of specific embodiments, it is obvious that the present invention is in no way limited thereto, and if all technical equivalents of the described devices and combinations of technical equivalents of the loading are within the scope of the present invention, then the present invention includes all technical equivalents of the described devices and combinations of technical equivalents of the loading.

[0090] The use of the verb "comprise" or "include" and its variants does not exclude the existence of elements or steps other than those listed in the claims. Unless otherwise stated, the use of the indefinite article "a" for an element or step does not exclude the existence of a plurality of such elements or steps.

[0091] In the claims, any reference signs in parentheses shall not be construed as limiting the claim.

Claims

1. A liquefied gas storage device, the liquefied gas storage device comprising a load-bearing structure and a sealed and thermally insulated tank (71), the sealed and thermally insulated tank being arranged in the load-bearing structure, The sealed and thermally insulated tank (71) comprises a main structure formed by a plurality of tank walls, the plurality of tank walls being connected to each other and fixed to the load-bearing structure, the main structure defining an internal storage space, the main structure comprising at least one sealing film (3, 13, 13') and at least one thermal insulation shield, the thermal insulation shield being arranged between the sealing film (3, 13, 13') and the load-bearing structure; The sealing film (3, 13, 13') of the main structure, the thermal insulation shield and the upper load-bearing wall are locally interrupted to define a pipe, the pipe forming the load-bearing wall of a chimney portion, the chimney portion extending along a vertical axis to an upper end portion, the upper end portion comprising a loading / unloading opening, through which a liquefied gas loading / unloading pipe can pass, the pipe leading to the opening defining a liquid dome (2) of the tank (71), the liquid dome comprising at least one sealing film (3, 33) and at least one thermal insulation shield, the thermal insulation shield being arranged between the sealing film (3, 33) and the load-bearing wall; The liquid dome (2) is located at an axial end of the tank (71), and a vertical wall, called an enclosing wall (B), of the main structure of the tank (71) extends from the main structure to form a wall (B') of the pipe of the liquid dome (2) along the same plane; The sealing films (3, 13, 13', 33) of the main structure and the sealing film of the liquid dome (2) are composed of a plurality of flat metal films that can be hermetically fixed together, each metal film having at least two rows of vertical corrugations (4, 5), the shapes and dimensions of the two rows of corrugations (4, 5) being the same for all the metal films, such that the juxtaposed metal films display a repeated pattern; Characterized in that, Adjacent films (13, 13') in the sealing film of the enclosing wall (B) of the main structure of the tank (71) at least partially project into the liquid dome (2), and the adjacent films can be directly hermetically fixed to the adjacent films of the liquid dome (2), wherein the adjacent films of the main structure are closest to the liquid dome, and the adjacent films of the liquid dome are closest to the main structure.

2. The liquefied gas storage device according to claim 1, wherein, The flat metal films (3, 13, 13', 33) have a rectangular shape with two long sides and two short sides, and the flat metal films form the sealing films of the main structure and the liquid dome (2).

3. The liquefied gas storage device according to claim 1 or 2, wherein The flat metal film comprises a raised portion (7) extending along two adjacent sides, the raised portion being adapted to overlap an adjacent side of another metal film.

4. The liquefied gas storage device according to claim 1 or 2, wherein The thermal insulation shields of the main structure of the tank (71) and the thermal insulation shield of the liquid dome (2) comprise metal plates, and the sealing films (3, 13, 13' 33) of the main structure and the sealing film of the liquid dome (2) are discontinuously welded to the metal plates.

5. The liquefied gas storage device according to claim 2, wherein, The adjacent membranes of the liquid dome (2) include raised portions (7) extending along the lower long side, while the directly adjacent membranes of the main structure of the tank (71, 71') include raised portions (7) extending along one of the two short sides of the metal membrane.

6. The liquefied gas storage device according to claim 1 or 2, wherein, The protruding portion (17) of the adjacent membrane (13) in the sealing membrane of the enclosing wall (B) of the main structure of the tank (71) protrudes into the liquid dome (2) by at least 30 mm.

7. The liquefied gas storage device according to claim 1 or 2, wherein, The protruding portion (17) of the adjacent membrane (13) in the sealing membrane of the enclosing wall (B) of the main structure of the tank (71) protrudes into the liquid dome (2) by at most 60 mm.

8. The liquefied gas storage device according to claim 1 or 2, wherein, The length of the adjacent membranes of the liquid dome (2) is between 500 mm and 3300 mm, and the width of the adjacent membranes is between 200 mm and 800 mm.

9. The liquefied gas storage device according to claim 1 or 2, wherein, The length of the adjacent membranes (13, 13') in the sealing membrane of the enclosing wall (B) of the main structure of the tank (71) is between 500 mm and 3300 mm, and the width of the adjacent membranes is between 200 mm and 800 mm.

10. The liquefied gas storage device according to claim 9, wherein, The adjacent membranes (13, 13') in the sealing membrane of the enclosing wall (B) of the main structure of the tank (71, 71') are in two rows of parallel membranes. The width of one row of membranes (13') is between 200 mm and 400 mm, and the width of the other row of membranes (13) is between 700 mm and 800 mm.

11. The liquefied gas storage device according to claim 6, wherein, The protruding portion (17) of the adjacent membrane (13) in the sealing membrane of the enclosing wall (B) of the main structure of the tank (71) protrudes into the liquid dome (2) by 55 mm.

12. A method for assembling a liquefied gas storage device according to any one of the preceding claims, wherein, The method includes: - A first step of sealingly assembling and fixing the sealing membrane assembly (3, 13, 13') of the enclosing wall (B) of the main structure of the tank; - A second step of sealingly assembling and fixing the sealing membrane assembly (3) of the liquid dome (2) except for the adjacent membranes of the liquid dome (2); The first step and the second step are performed in any order or simultaneously; - A final step of sealingly assembling and fixing the adjacent membranes (33) of the liquid dome (2) such that the assemblies of the enclosing walls (B, B') of the main structure and the liquid dome (2) are sealed.

13. A ship (70) for transporting cryogenic liquid products, the ship including a double hull (72) and a liquefied gas storage device (1) arranged in the double hull and according to any one of claims 1 to 11.

14. A system for transporting cryogenic liquid products, the system including the ship (70) according to claim 13, heat-insulated pipes (73, 79, 76, 81), and pumps. The heat-insulated pipes are arranged such that the heat-insulated pipes connect the tank (71) installed in the hull of the ship to a floating or onshore external storage device (77), and the pumps are used to transport a flow of cryogenic liquid products through the heat-insulated pipes from the floating or onshore external storage device to the ship's tank, or from the ship's tank to the floating or onshore external storage device.

15. A method for loading or unloading a ship (70) according to claim 13, wherein, The cold liquid product is transferred through insulated pipes (73, 79, 76, 81) from a floating or onshore external storage facility (77) to the tank (71) of the ship, or from the tank of the ship to a floating or onshore external storage facility.

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