Installation for storing a liquefied gas, ship for transporting a liquefied gas, transfer system for a liquefied gas and method for loading or unloading a ship

Abstract

The present invention relates to an apparatus for storing a liquefied gas, comprising a carrying structure (1) and a sealed and thermally insulated chamber disposed in the carrying structure (1), the carrying structure (1) comprising a dome structure (19) projecting vertically from an upper carrying wall (3) toward the outside of the chamber, the dome structure (19) comprising a vertical dome wall (22) projecting upward from the upper carrying wall (3) and each comprising an upper end, the dome structure (19) comprising a horizontally continuous seat wall (23) and comprising a peripheral boundary region (33), the dome structure (19) comprising a cover (25) covering the passage and welded to the seat wall (23) in a sealed manner, the cover (25) being welded to at least one intermediate plate (34), the intermediate plate (34) being welded to the seat wall (23) in the peripheral boundary region (33).

Description

Technical Field

[0001] This invention relates to the field of liquefied gas storage equipment, which includes a sealed and thermally insulated chamber disposed in a carrying structure.

[0002] Specifically, this invention relates to the field of sealed and thermally insulated compartments for storing and / or transporting liquefied gases at cryogenic temperatures (such as compartments for transporting liquefied petroleum gas (LPG) having a temperature between -50°C and 0°C, or for transporting liquefied natural gas (LNG) at approximately -162°C). These compartments can be installed on shore or on a floating structure. In the case of a floating structure, the compartment can be used to transport liquefied gases or to receive liquefied gases used as fuel for propelling the floating structure.

[0003] More specifically, the present invention relates to a storage device of one of the aforementioned types, comprising a dome structure projecting upward from an upper load wall of a load-bearing structure and for allowing at least one pipeline for loading or unloading a compartment to pass through. Prior Technology

[0004] Document WO2015155377 discloses an apparatus for storing a liquefied gas, comprising: a loading structure consisting of a double hull of a vessel and a sealed and thermally insulated compartment disposed within the loading structure. The apparatus includes a dome structure, as shown in Figure 4 of the aforementioned document, which serves as a penetration point for various equipment and articles within the compartment, such as pipelines for loading or unloading the compartment. The dome structure projects upward from an upper loading bulkhead. It includes a vertical loading bulkhead rising above the deck of the vessel and a horizontal wall positioned at the top of the vertical loading bulkhead. The horizontal wall is supported by a cover consisting essentially of a metal cover wall and thermal insulation inserted into the top of the dome structure.

[0005] To secure the horizontal walls and metal cap of the dome structure and ensure its airtightness, a known method involves creating a weld along the periphery of the metal cap. When the prevailing pressure inside the chamber is higher than atmospheric pressure, this pressure difference exerts a force on the cap towards the outside, causing the metal cap to flex. This stress can degrade the aforementioned weld and thus lead to sealing problems in the dome structure, especially when the chamber is used to store gas at pressures higher than those in conventional chambers with membranes.

[0006] Therefore, this dome structure configuration is not entirely satisfactory. Summary of the Invention

[0007] Therefore, a basic concept of the present invention is to propose a device for storing liquefied gases, which includes a dome structure with better pressure resistance.

[0008] To this end, according to one embodiment, the present invention provides an apparatus for storing a liquefied gas, comprising a loading structure and a sealed and thermally insulated chamber disposed within the loading structure, the loading structure including an upper loading wall and the chamber including a ceiling wall fastened to the upper loading wall, the upper loading wall and the ceiling wall being partially interrupted to define an opening, the loading structure including at least one [unclear - possibly a device or structure] projecting from the upper loading wall around the opening toward the exterior of the chamber and defining [unclear - possibly a device or structure] for loading liquefied gas into or unloading liquefied gas from the chamber. A pipeline passes through a dome structure of a channel, the dome structure including dome walls projecting from the upper support wall and each including an upper end, the dome structure including a seat wall fastened to the upper ends of the vertical dome walls, the seat wall extending horizontally and including a peripheral boundary region bordering the channel and projecting from the vertical dome walls toward the channel, the dome structure including a cover covering the channel and welded to the seat wall in a sealing manner, the cover being welded to at least one intermediate plate, the intermediate plate being welded to the seat wall in the peripheral boundary region.

[0009] Therefore, since the cover is welded to the peripheral boundary region (which is the area of ​​the seat wall closest to the center of the dome structure), the torque applied to the welds is reduced when the pressure inside the compartment is higher than the pressure outside the compartment. This limits the deflection of the cover and improves the pressure resistance of the welds that fasten the cover to the seat wall. Furthermore, using an intermediate plate distributes the force across a larger number of welds. Additionally, the intermediate plate forms an additional reinforcing strip between the cover and the seat wall, capable of absorbing some of the force through deformation.

[0010] Depending on the embodiment, this device may have one or more of the following characteristics.

[0011] According to one embodiment, the intermediate plate is welded to the peripheral boundary region along one of the inner edges of the peripheral boundary region. This allows the intermediate plate to be secured to the seat wall by a fillet weld that is simple to implement and ensures good fastening performance.

[0012] According to one embodiment, the cover is welded to a plurality of intermediate plates disposed around the channel and preferably welded to the seat wall in the peripheral boundary region along the inner edge of the peripheral boundary region.

[0013] According to one embodiment, the intermediate plates protrude toward the interior of the dome structure. Therefore, the intermediate plates extend toward the channel beyond the inner edge of the peripheral boundary region.

[0014] According to one embodiment, the intermediate plate is welded to the cover by using at least one continuous or discontinuous weld extending along at least one edge of the intermediate plate.

[0015] According to one embodiment, the intermediate plate is welded to the cover using at least two welds extending along at least two edges of the intermediate plate, respectively, on either side of the inner edge of the peripheral boundary region. This allows the force to be distributed over a larger weld surface and secures the intermediate plate to the cover using fillet welds that are easy to implement and ensure satisfactory fastening performance.

[0016] According to one embodiment, the cover is welded to the seat wall in a sealed manner by using an intermediate frame disposed around the channel and around the at least one intermediate plate.

[0017] According to one embodiment, the intermediate frame is welded to the seat wall by at least one sealing weld extending along the inner or outer peripheral edge of one of the intermediate frames. According to one embodiment, the sealing weld is a continuous weld.

[0018] According to one embodiment, the cover is welded to the intermediate frame by at least one sealing weld. The at least one sealing weld preferably extends along the outer peripheral edge of the cover. Thus, these welds, ensuring a seal between the cover and the seat wall, are positioned outside the additional fastening area between the cover and the seat wall, such that they are only affected by forces generated by the prevailing positive pressure within the compartment. According to one embodiment, the sealing weld is a continuous weld.

[0019] According to one embodiment, the intermediate frame is welded to the seat wall using two welds, one extending along the inner edge and the other along the outer edge of the intermediate frame. According to a first embodiment variant, the weld extending along the outer peripheral edge of the intermediate frame is continuous and sealed, while the weld extending along the inner peripheral edge of the intermediate frame is discontinuous. According to a second embodiment variant, the weld extending along the inner peripheral edge of the intermediate frame is continuous and sealed, while the weld extending along the outer peripheral edge of the intermediate frame is discontinuous. Finally, according to a third embodiment variant, both welds are sealed, further enhancing the reliability of the seal.

[0020] According to one embodiment, the chamber includes a chamber wall anchored to each of the dome walls, each chamber wall including a primary sealing membrane for contacting the liquefied gas contained in the chamber, the dome structure including the primary sealing membrane welded to a profiled frame thereto, the profiled frame being welded to the peripheral boundary region of the chamber wall via a sealing weld. Therefore, under thermal contraction, the primary sealing membrane exerts a force on the peripheral boundary region of the chamber wall in the opposite direction to a force applied to the peripheral boundary region, this force being generated by the pressure exerted on the cover by the gas phase of the liquefied gas, which may further restrict the deflection of the chamber wall and the cover.

[0021] Furthermore, the intermediate plate and the peripheral boundary region form a heat conduction area from the cover toward the molded frame, which may limit the temperature drop of the molded frame and thus limit the thermal stress acting on the molded frame.

[0022] According to one embodiment, the molded frame has an L-shaped cross-section, including a first branch and a second branch perpendicular to each other, the first branch being welded to the main sealing film and the peripheral boundary region and extending vertically, and the second branch extending horizontally and fastened to a fastening protrusion protruding toward the ceiling wall (i.e., downward from the peripheral boundary region of the seat wall).

[0023] According to one embodiment, the molded frame includes reinforcing gussets, each having a first edge pressing against the first branch and a second edge pressing against the second branch.

[0024] According to one embodiment, the device includes a loading / unloading tower through one of the channels defined by the dome structure, the loading / unloading tower including at least two vertical masts through the cover and fastened to each other by crossbeams, each of the two vertical masts forming a pipeline for loading or unloading one of the compartments.

[0025] According to one embodiment, the ceiling wall and each bulkhead anchored to one of the dome walls include a primary thermal insulation barrier against the carrying structure, a primary sealing film against the secondary thermal insulation barrier, a primary thermal insulation barrier against the secondary sealing film, and a primary sealing film against the primary thermal insulation barrier and for contact with liquefied gas contained in the compartment.

[0026] One of the compartments according to one of the foregoing embodiments can form, for example, part of an onshore storage facility for storing LNG, or it can be installed in a coastal or deep-water floating structure, specifically a methane transport vessel or methane carrier, a floating storage and regasification unit (FSRU), a floating production storage and offloading (FPSO) unit, and the like. In the case of a floating structure, the compartment can be used to receive liquefied natural gas used as fuel for the propulsion of the floating structure.

[0027] According to one embodiment, the present invention relates to a vessel for transporting a fluid, which includes one of the aforementioned types of equipment.

[0028] According to one embodiment, the vessel includes a double hull that forms the carrying structure.

[0029] According to one embodiment, the present invention also provides a fluid transfer system comprising the aforementioned vessel, an insulated pipeline configured to connect the vessel’s compartment to a floating or shore-based storage device, and a pump for transferring a fluid flow rate from the floating or shore-based storage device to the vessel’s compartment or from the vessel’s compartment to the floating or shore-based storage device through the insulated pipeline.

[0030] According to one embodiment, the present invention also provides a method for loading or unloading a vessel, wherein a fluid is transported through insulated pipelines from a floating or shore-based storage device to the vessel’s compartment or from the vessel’s compartment to a floating or shore-based storage device. Simple Explanation of the Diagram

[0031] The invention will be better understood, and further objects, details, features and advantages of the invention, given only by way of illustration and not by way of limitation, will become clearer during the following description of several specific embodiments of the invention, with reference to the accompanying drawings.

[0032] Figure 1 is a schematic perspective view of a carrying structure used to support a sealed and thermally insulated chamber for storing a liquefied gas.

[0033] Figure 2 is a schematic diagram of one of the multi-layered structures of the cabin wall.

[0034] Figure 3 is a schematic diagram of one cross-section of the dome structure.

[0035] Figure 4 shows a cross-sectional view of a portion of the dome structure's cover being fastened to the base wall.

[0036] Figure 5 is a perspective view of the dome structure as seen from below.

[0037] Figure 6 is a detailed view of one of the areas of Figure 5 in which the cover is fastened to one of the intermediate parts of the seat wall.

[0038] Figure 7 is a three-dimensional view of the dome structure as seen from above.

[0039] Figure 8 shows a portion of the forming frame formed from one of the holding regions of the main sealing film.

[0040] Figure 9 is a partial representation of the angle of a self-molded frame according to one embodiment of Figure 7.

[0041] Figure 10 is a cross-sectional schematic diagram of a methane transport vessel's hold and one of the terminal facilities used for loading / unloading this hold. Implementation

[0042] Referring to Figure 1, the figure depicts a sealed and thermally insulated compartment for storing a liquefied gas, secured to a loading structure 1. The loading structure 1 is, for example, formed by the double hull of a vessel. The loading structure 1 has a polyhedral overall shape. It has two loading walls 2, which are octagonal in shape, with only the aft loading wall shown in Figure 1. For example, the forward and aft walls 2 are cofferdam walls extending laterally relative to the longitudinal direction of the vessel. The loading structure 1 also includes an upper loading wall 3, a lower loading wall 4, and transverse loading walls 5, 6, 7, 8, 9, and 10.

[0043] The sealed and thermally insulated compartment for storing liquefied gases includes a plurality of compartment walls, each of which is anchored to one of the loading walls 2, 3, 5, 6, 7, 8, 9, and 10 of the loading structure 1.

[0044] As shown in Figure 2, each wall of the compartment, from the outside to the inside along the thickness direction, has a primary thermal insulation barrier 12 including an insulating element 13 fastened to the load-bearing structure 1, a primary sealing film 14 anchored to the insulating element 13 of the secondary thermal insulation barrier 12, a main thermal insulation barrier 15 including an insulating element 13 fastened to the secondary thermal insulation barrier 12 or the load-bearing structure 1 and abutting against the secondary sealing film 14, and a main sealing film 17 anchored to the insulating element 16 of the main thermal insulation barrier 15 and used for contact with the liquefied gas contained in the compartment.

[0045] As shown in Figures 3 and 7, the upper loading wall 3 and the ceiling wall 11 are partially interrupted to define an opening 18. The loading structure 1 includes a dome structure 19 that protrudes upward from the upper loading wall 3 around the opening 18 and defines a passage 24 for allowing one or more pipelines 20, 21, 47 for loading or unloading the compartment to pass through.

[0046] The dome structure 19 includes vertical dome walls 22. For example, when the dome structure 19 has a cross-section of a square or rectangular shape, the number of dome walls 22 is 4. The dome walls 22 project upward from the superstructure wall 3 and rise above the ship's deck. The dome structure 19 also includes a seat wall 23 located at the top of the dome walls 22, which extends horizontally around the passage 24 formed by the dome walls 22 and thus forms a perimeter together with the dome walls 22. The seat wall 23 supports a cover 25 through which pipelines or pipelines 20, 21 for loading or unloading the tanks pass for loading or unloading. The cover 25 includes a metal cover plate and thermal insulation (not shown) fastened to the underside of the metal cover plate and inserted into the dome structure 19. As illustrated in Figures 3 and 7, according to one embodiment, the cover 25 includes a network of reinforcing strips 48 each formed by metal plates welded to the top of the metal cover plate.

[0047] In addition, the load-bearing structure also includes a reinforcing strip 49 that is fastened to the underside of the seat wall 23 and presses against the upper load-bearing wall 3 and the dome wall 22.

[0048] As described above along with Figure 2, the multi-layered structure of the cabin also exists on the dome wall 22 but not on the horizontal surface of the dome structure 19 cover.

[0049] In the embodiment shown in Figure 3, a loading / unloading tower 26 passes through the interior of a passage 24 defined by a dome structure 19. The loading / unloading tower 26 includes three vertical masts 20, 21, two of which are shown in Figure 3, each mast being fastened to each other by a crossbeam 27. The three vertical masts 20, 21 pass through the cover 25 of the dome structure 19 and extend substantially over the entire height of the compartment. The loading / unloading tower 26 includes a base (not shown) that cooperates with a support leg fastened to one of the lower loading walls 4 and thus serves to hold the loading / unloading tower 26 in a vertical position.

[0050] According to one embodiment, each of the masts 20 and 21 is hollow, and is formed by a dome structure 19: - A pipeline used to load the compartment with liquefied gas. - A pipeline used for unloading liquefied gas from the tank and associated with an unloading pump fastened to the lower end of the pipeline for this purpose, or - An emergency shaft that allows for the lowering of an emergency pump and an unloading line in the event of a failure of an unloading pump.

[0051] Together with Figure 4, the following describes the structure of the cover 25, and more specifically its metal plate, fastened to the seat wall 23 and at the top of the bulkhead fastened to the dome wall 22.

[0052] The cover 25 is secured to the seat wall 23 in a sealed manner. For this purpose, the cover 25 is welded in a sealed manner to an intermediate metal frame 28 that is itself pre-welded to the seat wall 23 in a sealed manner. Advantageously, the intermediate frame 28 is welded to the seat wall 23 in a sealed manner using two consecutive fillet welds 29, 30 extending along the inner and outer peripheral edges of the intermediate frame 28, respectively. Furthermore, the peripheral edge 39 of the cover 25 abuts against the upper surface of the intermediate frame 28 and is welded to the upper surface of the intermediate frame 28 in a sealed manner by a consecutive fillet weld 31. In the embodiment shown in the figures, the intermediate frame 28 at least partially abuts against an outer region 32 of the seat wall 23, i.e., a region located outside the dome wall 22 of the channel 24.

[0053] Furthermore, the base wall 23 includes a peripheral boundary region 33 that protrudes horizontally toward the channel 24 relative to the dome wall 22. Additionally, the cover 25 is also secured to the base wall 23 by a plurality of intermediate metal plates 34 as shown in Figures 4, 5, and 6. The intermediate plates 34 are regularly arranged along the peripheral boundary regions 33 and protrude in a direction inside the dome structure 19 relative to the inner edge 37 of the peripheral boundary regions 33. According to the exemplary embodiment shown in Figures 5 and 6, the intermediate plate 34 has a narrow, elongated shape following the inner edge 37 of the peripheral boundary regions 33 and has an L-shaped corner bracket at the corner between two adjacent dome walls 22.

[0054] Before welding to the peripheral boundary region 33 of the seat wall 23, each of the intermediate plates 34 is pre-welded to the cover 25. In the embodiment shown in FIG4, each of the intermediate plates 34 is filled-in welded to the inner surface of the cover 25 by at least two welds 35, 36. The two welds 35, 36 are formed along the two edges of the intermediate plate 34 disposed on either side of the inner edge 37 of the peripheral boundary region 33. According to a variant embodiment, the intermediate plate 34 is welded to each of its edges against the inner surface of the cover 25.

[0055] Furthermore, the seat wall 23 and each intermediate plate 34 are fastened to each other by a fillet weld 38 formed along the inner edge 37 of the peripheral boundary region 33 and abutting against the underside of each intermediate plate 34. It is particularly advantageous to use the intermediate plate 34 to fasten the cover 25 to the peripheral boundary region 33, because it can withstand the force applied to the cover 25 when the main pressure inside the compartment is higher than atmospheric pressure, and thus release the weld 31 formed on the outside of the dome structure 19 that ensures the seal of the cover 25 to the seat wall 23. Additionally, the intermediate plate 34 is advantageous because it can distribute the force over a larger welded surface. Furthermore, the intermediate plate 34 forms an intermediate reinforcing strip between the cover 25 and the seat wall 23, which can elastically deform to partially absorb the force applied to the cover 25 when the prevailing pressure inside the compartment is higher than atmospheric pressure. Finally, since the welds 36, 37, and 38 that fasten the cover 25 to the peripheral boundary area of ​​the seat wall 23 are positioned as close as possible to the center of the dome structure 19, the torque applied to these welds 36, 37, and 38 is reduced under normal pressure conditions in the cabin.

[0056] Furthermore, as shown in Figure 4, the dome structure 19 includes a molded frame 40 welded thereto to the main sealing membrane 17 and forming one of the holding regions of the main sealing membrane (i.e., one region located at the top of the dome structure 19), wherein the main sealing membrane 17, which is mounted against the bulkhead of the dome wall 22, is anchored to the carrying structure 1. The molded frame 40 is welded to the peripheral boundary region 33 of the seat wall 23 and continuously surrounds the seat wall 23 to ensure the sealing of the main sealing membrane 17.

[0057] Due to its thermal shrinkage, the main sealing film 17 applies a force to the peripheral boundary region 33 of the seat wall 23 in the opposite direction to the force applied to the peripheral boundary region 33 due to the pressure applied to the cover 25. Therefore, this configuration can further limit the deflection of the seat wall 23 and the cover 25.

[0058] As shown in Figures 4 and 8, the molded frame 40 has an L-shaped cross-section (i.e., it includes a first branch 41 and a second branch 42 that are perpendicular to each other). The first branch 41 extends vertically in the plane of the main sealing film 17. The first branch 41 has a free end that is welded to the peripheral boundary region 33 of the seat wall 23 by a weld 43. In addition, the main sealing film 17 abuts against the first branch 41 and is welded thereto at the top of the dome structure 19. The second branch 42 extends parallel to the thickness direction of the wall. Furthermore, it is welded to a fastening protrusion 44 that protrudes vertically downward from the peripheral boundary region 33 of the seat wall 23 via a weld 45.

[0059] According to one embodiment variant shown in FIG9, the molding frame 40 includes reinforcing corner plates 46 each having a first edge pressing against a first branch 41 of the molding frame 40 and a second edge pressing against a second branch 42 of the molding frame 40.

[0060] The dome structure 19 also includes a peripheral boundary region 33 welded to the seat wall 23, and a primary sealing plate 50 (partially shown in Figure 4) to which a secondary sealing membrane is fastened continuously around the seat wall 23 and abuts against the dome wall 22.

[0061] Specifically, the liquefied gas to be stored in the tank can be liquefied natural gas (LNG) (i.e., a gaseous mixture mainly consisting of methane and one or more other hydrocarbons). The liquefied gas can also be ethane or liquefied petroleum gas (LPG) (i.e., a mixture of hydrocarbons obtained by refining petroleum and essentially consisting of propane and butane).

[0062] Referring to Figure 10, a cross-sectional view of a methane carrier 70 shows a sealed and insulated compartment 71 of a prismatic overall shape installed in the vessel's double hull 72. The walls of compartment 71 include a primary sealing barrier for contact with the LNG contained in the compartment, a secondary sealing barrier disposed between the primary sealing barrier and the vessel's double hull 72, and two insulating barriers disposed between the primary sealing barrier and the secondary sealing barrier, and between the secondary sealing barrier and the double hull 72, respectively.

[0063] In one of the ways known per se, the loading / unloading pipeline 73 located on the deck of a vessel can be connected by a suitable connector to a marine or port terminal facility to transfer an LNG cargo from or to hold 71.

[0064] Figure 10 illustrates an example of a marine terminal facility including a loading and unloading station 75, an underwater pipeline 76, and a shore-based facility 77. The loading and unloading station 75 is a fixed shore-based facility including a boom 74 and a tower 78 supporting the boom 74. The boom 74 carries a bundle of insulated flexible tubing 79 that can be connected to the loading / unloading pipeline 73. The directional boom 74 is adaptable to all gauges of the methane carrier. A connecting pipe (not shown) extends inside the tower 78. The loading and unloading station 75 can load methane carrier 70 from or unload methane carrier 70 onto the shore-based facility 77. The latter includes a liquefied gas storage tank 80 and a connecting pipe 81 connected to the loading and unloading station 75 via the underwater pipeline 76. The underwater pipeline 76 can transport liquefied gas over a relatively long distance (e.g., 5 km) between the loading or unloading station 75 and the shore equipment 77, which makes it possible to keep the methane transport vessel 70 at a relatively long distance from the coast during loading and unloading operations.

[0065] To generate the pressure necessary for transferring liquefied gas, pumps installed on the vessel 70 and / or pumps mounted in the shore equipment 77 and / or pumps mounted on the loading and unloading station 75 are used.

[0066] Although the invention has been described in conjunction with several specific embodiments, it is quite obvious that the invention is by no means limited thereto and that if such fall within the scope of the invention, it includes all technical equivalents of the described manner, and combinations thereof.

[0067] The use of the verbs “have,” “include,” or “contain,” and their conjugate forms, does not exclude the presence of elements or steps other than those mentioned in a claim.

[0068] Any references between parentheses in the scope of the patent application shall not be interpreted as limiting the scope of the patent application.

[0069] 1: Load-bearing structure 2: Load-bearing wall / front wall / rear wall 3: Superior load-bearing wall 4: Lower load wall 5: Lateral load-bearing wall 6: Lateral load-bearing wall 7: Lateral load-bearing wall 8: Lateral load-bearing wall 9: Lateral load-bearing wall 10: Lateral load-bearing wall 11:ceiling wall 12: Secondary thermal insulation barrier 13: Insulating elements 14: Secondary sealing film 15: Main thermal insulation barrier 16: Insulating elements 17: Main sealing film 18: Opening 19: Dome Structure 20: Pipelines 21: Pipeline 22: Vertical dome wall 23: Wall Seat 24: Cover 25: Cover 26: Loading / Unloading Tower 27: Crossbeam 28: Middle Metal Frame 29: Continuous fillet weld 30: Continuous fillet weld 31: Continuous fillet weld 32: Outer Area 33: Surrounding Boundary Area 34: Intermediate metal plate 35: Weld 36: Weld 37: Inner Edge 38: Fillet weld 39: External perimeter edge 40: Molded Frame 41: First Branch 42: Second Branch 43: Weld 44: Fastening protrusions 45: Weld 46: Reinforced corner plate 47: Pipelines 48: Strengthen the network 49: Strengthening Clause 50: Secondary enclosure plate 70: Methane Transport Ship 71: Insulation Chamber 72: Double Hull 73: Loading / Unloading Pipeline 74: Orientable Action Arm 75: Loading and unloading station 76: Underwater pipelines 77: Shore-based equipment 78: Tower 79: Insulated Flexible Conduit 80: Liquefied Gas Storage Tank 81: Connecting pipe

Claims

1. An apparatus for storing a liquefied gas, comprising a loading structure (1) and a sealed and thermally insulated chamber disposed therein, the loading structure (1) including an upper loading wall (3) and the insulated chamber including a ceiling wall (11) fastened to the upper loading wall (3), the upper loading wall (3) and the ceiling wall (11) being partially interrupted to define an opening (18), the loading structure (1) including a dome structure (19) extending vertically from the upper loading wall (3) around the opening toward the outside of the insulated chamber and defining a channel (24) through which at least one pipeline (20, 21) for loading or unloading liquefied gas into or from the insulated chamber passes, the dome structure ( 19) includes dome walls (22) projecting from the upper support wall (3) and each includes an upper end. The dome structure (19) includes a seat wall (23) fastened to the upper ends of the dome walls (22). The seat wall (23) is horizontally continuous and includes a peripheral boundary region (33) that borders the channel (24) and projects from the dome walls (22) toward the channel (24). The dome structure (19) includes a cover (25) that covers the channel and is welded to the seat wall (23) in a sealing manner. The cover (25) is welded to at least one intermediate plate (34). The intermediate plate (34) is welded to the seat wall (23) in the peripheral boundary region (33) along an inner edge (37) of the peripheral boundary region (33).

2. The device of claim 1, wherein the cover (25) is welded to a plurality of intermediate plates (34) disposed around the passage and each along the inner edge (37) of the peripheral boundary region (33) is welded to the seat wall (23) in the peripheral boundary region (33).

3. The device of claim 1 or 2, wherein the intermediate plate (34) protrudes toward the interior of the dome structure (19), and wherein the intermediate plate (34) is welded to the cover (25) by means of at least one weld (35, 36) extending along at least one edge of the intermediate plate (34).

4. The device of claim 3, wherein the or each intermediate plate (34) is welded to the cover (25) by means of at least two welds (35, 36) extending along at least two edges of the intermediate plate (34) on either side of the inner edge (37) of the peripheral boundary region (33).

5. The device as claimed in claim 1 or 2, wherein the cover (25) is welded to the seat wall (23) in a sealed manner by using an intermediate frame (28) disposed around the channel (24) and around the at least one intermediate plate (34).

6. The device of claim 5, wherein the intermediate frame (28) is welded to the seat wall (23) by at least one sealing weld (29, 30) extending along one of the inner or outer peripheral edges of the intermediate frame (28).

7. The device of claim 5, wherein the cover (25) is welded to the intermediate frame (28) by at least one sealing weld (31), the at least one sealing weld (31) preferably extending along one of the outer peripheral edges (39) of the cover (25).

8. The device of claim 1 or 2, wherein the insulating chamber includes a chamber wall anchored to each of the dome walls (22), each chamber wall including a primary sealing membrane (17) for contact with the liquefied gas contained in the insulating chamber, the dome structure (19) including a molded frame (40) to which the primary sealing membrane (17) is welded and to the peripheral boundary region (33) of the seat wall (23) by a sealing weld (43).

9. The device of claim 8, wherein the molded frame (40) has an L-shaped cross section comprising a first branch (41) and a second branch (42) perpendicular to each other, the first branch (41) being welded to the main sealing film (17) and the peripheral boundary region (33) and extending vertically, and the second branch (42) extending horizontally and fastened to a fastening protrusion (44) protruding from the peripheral boundary region (33) of the seat wall (23) toward the ceiling wall (11).

10. The device of claim 9, wherein the molded frame (40) includes reinforcing corner plates (46) each having a first edge pressing against the first branch (41) and a second edge pressing against the second branch (42).

11. The equipment as claimed in claim 1 or 2, comprising a loading / unloading tower (26) through the passage (24) defined by the dome structure (19), the loading / unloading tower (26) comprising at least two vertical masts fastened to each other by the cover (25) and by crossbeams (27), each of the two vertical masts forming a pipeline for loading or unloading one of the insulating chambers.

12. The equipment as claimed in claim 1 or 2, wherein the ceiling wall (11) and each bulkhead anchored to one of the dome walls (22) comprises a primary thermal insulation barrier (12) against the carrying structure (1), a primary sealing membrane (14) against the secondary thermal insulation barrier (12), a primary thermal insulation barrier (15) against the secondary sealing membrane (14), and a primary sealing membrane (17) against the primary thermal insulation barrier (15) for contact with the liquefied gas contained in the insulating chamber.

13. A vessel (70) for transporting a liquefied gas, the vessel including equipment as claimed in claim 1 or 2.

14. A system for conveying a liquefied gas, the system comprising a vessel (70) as claimed in claim 13, insulated lines (73, 79, 76, 81) configured to connect the insulated compartment (71) of the vessel to a floating or shore storage facility (77), and a pump for conveying a liquefied gas from the floating or shore storage facility to the insulated compartment of the vessel, or from the insulated compartment of the vessel to the floating or shore storage facility, through the thermally insulated lines.

15. A method for loading or unloading a vessel (70) as claimed in claim 13, wherein a liquefied gas is transported from a floating or shore storage facility (77) to the insulated compartment (71) of the vessel or from the insulated compartment (71) of the vessel to a floating or shore storage facility (77) via the insulated lines (73, 79, 76, 81).

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