CN111094833B

CN111094833B - Sealed and thermally insulated container comprising a gas-collecting dome

Info

Publication number: CN111094833B
Application number: CN201880058012.6A
Authority: CN
Inventors: 安托万·菲利普
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2017-08-07
Filing date: 2018-08-03
Publication date: 2021-10-26
Anticipated expiration: 2038-08-03
Also published as: KR102506308B1; RU2759040C2; RU2020104051A; RU2020104051A3; FR3069904A1; KR20200039723A; WO2019030447A1; FR3069904B1; CN111094833A

Abstract

The invention relates to a sealed and thermally insulated container for storing liquefied gas, comprising an upper wall with a multilayer structure, the container further comprising a gas collecting dome (1) comprising: -a vapour collection pipe (15); -a sheath (19) arranged around the vapor collection tube (15) and sealingly connected with the secondary sealing membrane (6), said sheath (19) being sealingly connected to the vapor collection tube (15) by means of an upper annular plate (20) extending transversely between the sheath (19) and the vapor collection tube (15) so as to provide a sealed primary space (22) communicating with the primary insulating barrier (7), the sheath (19) having, between the upper annular plate (20) and the secondary sealing membrane (6), a frustoconical portion (43) tapering towards the secondary sealing membrane (6); and-a primary discharge device for discharging fluid from the primary insulating barrier (7), the primary discharge device comprising a pipe (27) sealingly connected to the upper annular plate (20).

Description

Sealed and thermally insulated container comprising a gas-collecting dome

Technical Field

The present invention relates to the field of sealed and insulated containers for storing and/or transporting fluids such as cryogenic fluids.

Sealed and insulated containers are used in particular for storing Liquefied Natural Gas (LNG), which is stored at atmospheric pressure at about-162 ℃.

Background

The prior art, and in particular application WO 2015/155377, discloses a sealed and insulated container for storing liquefied natural gas equipped with a gas collection dome structure. The sealed and insulated container comprises a wall having, in order in the thickness direction: a secondary insulating barrier against the support structure, a secondary sealing membrane against the secondary insulating barrier, a primary insulating barrier against the secondary sealing membrane, and a primary sealing membrane for contact with the liquefied gas contained in the container.

The gas collection dome has a vapor collection tube for defining a vapor circulation passage between the interior space of the container and a vapor collector (not shown) located outside the container.

The gas collecting dome structure also integrates a primary discharge device which allows the discharge of the gas present in the primary insulating barrier. To this end, the primary discharge means comprises a pipe leading to the sealed primary space of the gas collection dome, communicating with the primary insulating barrier of the container.

The gas collection dome structures disclosed in the above-mentioned documents are not entirely satisfactory. In particular, only the discharge flow of the fluid present in the thermal insulation barrier can be generated, which is detrimental to the increase in volume of the gas collection dome in the vicinity of the secondary sealing membrane, which leads to the deterioration of the mechanical properties of the secondary sealing membrane in certain types of containers.

Disclosure of Invention

The idea behind the present invention is to propose a sealed and insulated container comprising a gas-collecting dome equipped with primary discharge means allowing the fluid present in the primary insulating barrier to be discharged, and which is able to rapidly discharge a large quantity of fluid present in the primary insulating barrier, and which does so without degrading the mechanical properties of the container wall in the vicinity of the gas-collecting dome.

According to one embodiment, the present invention provides a sealed and insulated container for storing liquefied gas, comprising an upper wall having, in order in a thickness direction: a secondary thermal barrier against a support structure, a secondary sealing membrane against the secondary thermal barrier, a primary thermal barrier against the secondary sealing membrane, and a primary sealing membrane for contact with the liquefied gas contained in the container, the container further comprising a gas collection dome comprising:

-a vapour collection pipe for extracting vapour resulting from evaporation of liquefied gas in the container, the vapour collection pipe passing through an opening provided in the support structure and through an upper wall of the container, the vapour collection pipe comprising a peripheral wall sealingly connected to the primary sealing membrane;

-a jacket disposed around the vapor collection tube, the jacket comprising a lower end sealingly connected with the secondary sealing membrane, the jacket being sealingly connected to the vapor collection tube by means of an upper annular plate extending transversely between the jacket and the vapor collection tube so as to provide a sealed primary space between the jacket and the vapor collection tube, the sealed primary space being in communication with the primary insulating barrier, the jacket having such a shape between the upper annular plate and the secondary sealing membrane: the shape is such that the sheath tapers towards the secondary sealing membrane; and

-a primary drain for draining fluid from the primary insulation barrier, the primary drain comprising a pipe sealingly connected to the upper annular plate and communicating with the primary insulation barrier through the sealed primary space.

Thus, due to the particular shape of the jacket, the section connecting the tube of the primary drain sealingly to the upper annular plate is associated with the majority of the jacket in the vicinity of the secondary sealing membrane. Thus, the cross-section of the tube of the primary discharge means can be optimized to achieve a sufficient discharge flow, and this optimization of the cross-section does not lead to an increase in the cross-section of the sheath in the vicinity of the secondary sealing membrane and therefore does not reduce the mechanical properties of the secondary sealing membrane.

Such a sealed and insulated container for storing a fluid may include one or more of the following features, according to embodiments.

According to one embodiment, the sheath has a shape such that: the shape is such that the outer diameter of the sheath tapers towards the secondary sealing membrane between the upper annular plate (20) and the secondary sealing membrane.

According to one embodiment, the jacket has, in the vicinity of the upper annular plate, an internal section along a plane orthogonal to the longitudinal direction of the gas collecting dome, which is greater than the internal section of the jacket in the vicinity of the sealed connection to the secondary sealing membrane.

According to one embodiment, the sheath has, between the upper annular plate and the secondary sealing membrane, a frustoconical portion tapering towards the secondary sealing membrane.

According to one embodiment, the sealed primary space communicates with the thermal insulation barrier through a passage provided between the vapor collection tube and the secondary sealing membrane and/or through the secondary sealing membrane.

According to one embodiment, the gas collection dome comprises an insulating liner disposed in the sealed primary space between the jacket and the vapor collection tube, a channel being disposed in the insulating liner connecting the tube to a primary insulating barrier.

According to one embodiment, the secondary sealing membrane has an opening through which the vapor collection tube passes, the diameter of the opening being greater than the diameter of the peripheral wall of the vapor collection tube so as to provide an annular channel between the peripheral wall of the vapor collection tube and the secondary sealing membrane that couples the sealed primary space and the primary insulating barrier.

According to one embodiment, the jacket has a lower end welded to a lower annular plate welded to the secondary sealing membrane and having an opening, the vapor collection tube passes through the opening of the lower annular plate, and the diameter of the opening of the lower annular plate is greater than the diameter of the peripheral wall of the vapor collection tube, thereby coupling the sealed primary space and the primary insulating barrier.

According to one embodiment, said channel is provided in said barrier liner such that from the tube of said primary drain towards said annular channel, said channel converges towards said vapour collection tube. This allows the tube of the primary drain to be positioned far enough from the vapor collection tube to allow the welding tool to pass.

According to one embodiment, the passage is provided in the insulation lining such that the cross section of the passage remains at all points greater than or equal to the cross section of the pipe of the primary drain.

According to one embodiment, the channel is formed by a series of cylindrical cavities cut into the insulation liner and communicating with each other.

According to one embodiment, the upper annular plate is positioned above the support structure.

According to one embodiment, the pipe of the primary drain is welded to the periphery of the opening provided in the upper annular plate.

According to one embodiment, the pipe of the primary discharge device is connected to a valve that is openable when the pressure in the primary insulation barrier is greater than a threshold pressure.

According to one embodiment, the secondary sealing membrane comprises a plurality of corrugated metal sheets sealingly welded together, and each corrugated metal sheet comprises at least two perpendicular corrugations. The above-described gas collection dome is particularly advantageous when the secondary sealing membrane is a corrugated membrane, since by limiting the size of the gas collection dome in the vicinity of the secondary sealing membrane, the number of corrugations interrupted by the gas collection dome can be limited, which allows the elastic loss of the secondary sealing membrane in the vicinity of the channels of the gas collection dome to be limited. This allows for uniformity in the manufacture of the corrugations and, in particular, for restrictions in the sealing connection between the jacket and the secondary sealing membrane to be limited.

According to one embodiment, the gas collection dome has a central axis, wherein two director lines of two central corrugations of the secondary sealing membrane perpendicular to each other intersect at the central axis of the gas collection dome.

According to one embodiment, each of the two central corrugations is disposed between two adjacent corrugations, the two adjacent corrugations of each of the two central corrugations defining a perimeter inside which the sheath is sealingly connected to the secondary sealing membrane.

According to one embodiment, the gas collection dome includes an outer shaft disposed about the vapor collection tube and the jacket, and the outer shaft is sealably welded to the support structure.

According to one embodiment, an annular channel is provided between the support structure and the jacket to allow circulation of fluid present in the secondary insulating barrier towards a secondary sealed space provided between the outer shaft and the vapor collection tube.

Such a vessel may form part of an onshore storage facility for storing LNG, for example, or may be installed in a floating, coastal or deep-sea structure, in particular an LNG tanker, a Floating Storage and Regasification Unit (FSRU), an offshore floating production and storage unit (FPSO) or the like.

According to one embodiment, a vessel for transporting fluids comprises a catamaran hull comprising an inner hull forming a support structure for the container, and the aforementioned container disposed in the catamaran hull.

According to one embodiment, the invention also provides a method for loading or unloading such a vessel, wherein the fluid is transferred from or from the vessel of the floating or onshore storage facility to the vessel's vessel via an insulated pipeline.

According to one embodiment, the present invention also provides a transfer system for a fluid, the system comprising: the aforementioned boat; an isolation pipe arranged to connect a vessel installed in the hull of the vessel to a floating or onshore storage facility; and a pump for transferring fluid from a floating or onshore storage facility to the vessel of the vessel or from the vessel to a floating or onshore storage facility through the insulated pipeline.

Drawings

The invention may be better understood, and other objects, details, features and advantages made apparent from the following description of several specific embodiments thereof, given by way of non-limiting illustration only, with reference to the accompanying drawings, in which:

figure 1 is a partial cross-sectional view of a sealed and insulated container and gas collection dome structure;

figure 2 is a cross-sectional view showing a detailed view of the lower part of the gas collection dome of figure 1;

figure 3 shows a secondary sealing membrane located in the region of the gas dome;

fig. 4 is a schematic cross-sectional view of a vessel of an LNG tanker and a terminal for loading/unloading the vessel.

Detailed Description

Referring to fig. 1, there is partially shown a sealed and insulated container for storing liquefied gas such as Liquefied Natural Gas (LNG) or Liquefied Petroleum Gas (LPG). The container is equipped with a gas collecting dome 1, which gas collecting dome 1 serves to define a vapor circulation channel between an inner space 2 of the container and a not shown vapor collector located outside the container.

The container is arranged inside the double hull of a ship comprising an outer hull 3 and an inner hull 4. The inner hull 4 forms the supporting structure of the container. The container is generally polyhedral in shape.

Each wall of the container has a multilayer structure comprising, from the outside to the inside in the thickness direction of the container: a secondary thermal insulation barrier 5 resting against the inner hull 4, a secondary sealing membrane 6 anchored on the secondary thermal insulation barrier 5, a primary thermal insulation barrier 7 resting against the secondary sealing membrane 6, and a primary sealing membrane 8 anchored on the primary thermal insulation barrier 7 and intended to come into contact with the fluid stored in the container.

The secondary thermal insulation barrier 5 comprises a plurality of secondary insulation panels anchored to the inner hull 4 by means of not shown resin beads and/or not shown studs welded to the inner hull 4. According to one embodiment, each secondary insulation panel has a polymer foam layer, for example made of polyurethane foam, sandwiched between two rigid outer and inner panels, for example made of plywood. Each rigid outer plate is equipped with a metal plate for anchoring the secondary sealing membrane 6.

The secondary sealing membrane 6 comprises a plurality of corrugated metal sheets. The corrugated metal sheets are arranged offset with respect to the secondary insulation panels of the secondary insulation barrier 5, so that each of said corrugated metal sheets extends jointly over four adjacent secondary insulation panels. The corrugated metal sheets of the secondary sealing film 6 are lap-welded together and also welded to the metal plates of the secondary insulating barrier 5 along the edges of the corrugated metal sheets. According to one embodiment, the corrugations of the secondary sealing membrane 5 protrude towards the outside of the container (i.e. towards the inner hull 4). The corrugations of the secondary sealing membrane are then received in grooves provided in the inner panel of the secondary insulation panel.

The primary insulating barrier 7 comprises a plurality of primary insulating panels. The primary insulation panel is anchored through a stud projecting from the secondary insulation panel through the secondary sealing membrane 6 towards the interior of the container. The primary insulation panel has a similar structure to its secondary insulation panel and comprises a polymer foam layer, for example made of polyurethane foam, sandwiched between two rigid outer and inner panels, for example made of plywood. Furthermore, each rigid outer panel of the secondary insulation panel is fitted with a metal plate for anchoring the primary sealing membrane 8.

The primary sealing film 8 is obtained by assembling a plurality of corrugated metal sheets. The corrugated metal sheets of the primary sealing film 8 are lap-welded together and also welded to the metal sheets of the primary insulating barrier 7 along the edges of the corrugated metal sheets. The corrugations of the primary sealing membrane 8 project towards the interior of the container.

Such a container and its arrangement in a gas-collecting dome structure are disclosed in particular in application WO 2016/166481, for example.

The gas collecting dome 1 comprises a cylindrical outer axis 9 extending in a longitudinal direction oriented orthogonally to the upper wall of the container. The outer shaft 9 passes through an opening 10 provided in the upper wall of the outer hull 3. The outer shaft 9 is welded to a collar 41, the collar 41 extending radially outwardly relative to the longitudinal axis of the outer shaft 9, and the collar 41 is welded to the outer hull 3 to secure the outer shaft 9 to the outer hull 3.

Furthermore, the lower end of the outer shaft 9 is sealingly welded to the inner hull 4 over the circumference of a circular opening 11 provided in the inner hull 4.

The upper end of the outer shaft 9 is hermetically closed by a removable cap 12. The cover 12 is fixed on an assembly jig 13 in the form of a ring extending transversely to the longitudinal direction of the outer shaft 9 and radially to the outside thereof. The cover 12 is fixed to the assembly jig by a plurality of fixing members. A sealing gasket, not shown, is compressed between the cover 12 and the assembly fixture 13 and thereby provides a seal between the inside and the outside of the outer shaft 9.

The cover 12 has a central orifice 14 for connection to a vapour collector, not shown, which is able to circulate the vapour towards a degassing mast, a burner, a device for propelling the ship, and/or a liquefaction device in which the gas in the gaseous phase is re-liquefied and then re-introduced into the vessel in the liquid phase.

Furthermore, the gas collecting dome 1 comprises a vapor collecting tube 15 anchored inside the outer shaft 9. The vapour collection pipe 15 is coaxial with the outer shaft 9 and passes through the twin hull by passing through the opening 10 provided in the outer hull 3 and the opening 11 provided in the inner hull 4 in that order. A vapor collection tube 15 also passes through the upper wall of the vessel. The vapour collection pipe 15 comprises a cylindrical peripheral wall which is sealably welded to the primary sealing membrane 8, thereby sealing the primary insulating barrier 7 with respect to the inner space 2 of the container. The vapor collection tube 15 has a lower end opening into the interior space 2 of the container. The vapor collection tube 15 thus provides a vapor circulation channel between the inner space 2 of the container and a vapor collector, not shown, which is arranged outside the container and is connected to the central aperture 14 provided in the lid 12.

In the embodiment shown, in order to prevent gas in the liquid phase from rising in the vapor collection pipe, the lower end of the vapor collection pipe 15 is fitted with a deflector or deflector 16, the deflector 16 being positioned orthogonally to the longitudinal direction of the vapor collection pipe 15, and the cylindrical peripheral wall of the vapor collection pipe 15 comprises an opening 17, which opening 17 allows the vapor phase present in the interior space 2 of the container to enter the vapor collection pipe 15.

Furthermore, the vapor collection pipe 15 is also equipped with a filter 17, and in this case, the filter 17 is provided at the upper end of the vapor collection pipe 15, so that a pressure drop is generated, and thereby gas in the liquid phase can be prevented from flowing through the vapor collection pipe 15 toward the vapor collector.

The gas collection dome 1 further comprises an annular insulating layer 18, which annular insulating layer 18 is evenly distributed over the outer extent of the vapor collection tube 15.

Furthermore, the gas collecting dome 1 comprises a jacket 19, which is shown in detail in fig. 2, which jacket 19 is coaxial with the vapor collection pipe 15 and is arranged radially between the vapor collection pipe 15 and the outer shaft 9.

The upper end of the jacket 19 is sealingly welded to the upper annular plate 20. An upper annular plate 20 surrounds the vapor collection tube 15 and is sealingly welded to said vapor collection tube 15. The upper ring plate 20 is arranged above the inner hull 4 and thus extends into the space between the inner and outer hulls 4, 3 of the twin hull. In the embodiment shown, the upper annular plate 20 supports the annular insulating layer 18, said annular insulating layer 18 being optionally adhered to the upper annular plate 20.

Furthermore, the sheath 19 is sealingly connected to the secondary sealing membrane 6. Thus, a sealed primary space 22 is provided between the jacket 19 and the vapor collection tube 15. For this purpose, a lower annular plate 21, which extends in a plane orthogonal to the longitudinal direction of the gas collecting dome 1, is sealingly welded to the secondary sealing membrane 6. Further, the lower annular plate 21 is welded to a tubular portion 23, the tubular portion 23 projecting toward the outside of the container, and the lower end portion of the sheath 19 is fitted to the tubular portion 23, the lower end portion of the sheath 19 being sealingly welded to the tubular portion 23.

The lower annular plate 21 has a circular opening 24 through which the vapor collection tube 15 passes, and the diameter of the circular opening 24 is larger than the diameter of the vapor collection tube 15. Further, the secondary sealing film 6 is not welded to the peripheral wall of the vapor collection pipe 15, and also has a circular opening 35 having a diameter larger than that of the vapor collection pipe 15. Thus, an annular channel 25 is provided around the vapor collection pipe 15, which annular channel 25 allows the fluid present in the primary insulating barrier 7 to circulate towards the sealed primary space 22 provided between the jacket 19 and the vapor collection pipe 15.

The jacket 19 comprises, between the lower annular plate 21 and the upper annular plate 22, a frustoconical portion 43, the diameter of which frustoconical portion 43 decreases from the outside towards the inside of the container. In other words, the sheath 19 has an internal diameter at the upper annular plate 22 that is greater than its internal diameter at the lower annular plate 21.

An insulating lining 26, for example made of polymer foam such as polyurethane foam, is arranged in the sealed primary space 22, i.e. between the jacket 19 and the vapour collection pipe 15.

Furthermore, the gas collecting dome 1 comprises primary discharge means for protecting the primary sealing membrane 8 from overpressure that may occur in the primary insulating barrier 7. Such a primary drain is particularly useful for venting vapours that may be generated within the primary insulating barrier 7 in the event of leakage of liquefied gas through the primary sealing membrane 8.

The primary exhaust means comprises a tube 27, which tube 27 passes through the outer shaft 9 and then extends alongside the vapour collection tube 9 within the annular barrier 18 until it reaches the upper annular plate 20. In the illustrated embodiment, the tubes 27 include coiled regions that allow for thermal expansion and contraction of the tubes 27.

The diameter of the pipe 27 is greater than 5cm and preferably greater than or equal to 7.5cm to allow sufficient discharge flow.

The tube 27 is sealingly connected to the upper annular plate 20, for example by welding. To this end, in the embodiment shown, the upper annular plate 20 has an opening into which the end of the tube 27 is inserted and a weld is produced between the tube 27 and the periphery of the opening. Due to the flared shape of the jacket 19, the upper annular plate 20 is larger in a direction transverse to the longitudinal direction of the gas collecting dome 1, which allows increasing the cross section of the tube 27 while providing sufficient clearance between the vapor collection tube 15 and the tube 27 to allow the passage of welding tools.

Furthermore, in the insulating liner 26, a channel 29 is provided facing the tube 27 to connect the tube 27 with an annular channel 25 provided around the vapor collection tube 15, which allows the fluid present in the primary insulating barrier 7 to be discharged towards the tube 27. The passage 29 is provided in the insulating liner 26 so that its passage section remains greater than or equal to the section of the pipe 27, which prevents the creation of bottlenecks that could limit the gas flow exiting the primary insulating barrier 7. Furthermore, channels 29 are provided in the insulating lining 26, so that from the pipe 27 to the annular channel 25, said channels 29 converge towards the central axis of the gas collecting dome 1 and thus towards the annular channel 25. To this end, in the embodiment shown, the channel 29 is formed by a series of cylindrical cavities cut into the insulating liner 26 and communicating with each other.

The pipe 27 is connected to a valve, not shown, which is closed by default and which opens when the pressure in the primary insulation barrier 7 exceeds a predetermined threshold pressure.

Furthermore, according to this embodiment, the plant also comprises primary inerting means which allow the circulation of an inert gas, such as nitrogen, in the primary insulating barrier 7. To this end, the collector dome 1 is equipped with a tube 30, which tube 30 passes through the outer shaft 9 and then extends alongside the vapor collection tube 15 within the annular insulating layer 18 until it reaches the upper annular plate 20. In the illustrated embodiment, the tube 30 also includes a coiled region that allows for thermal expansion and contraction of the tube 30.

The tube 30 is sealingly connected to the upper annular plate 20, for example by welding. The end of the tube 30 passes through an opening provided in the upper annular plate 20 and is welded to the periphery of the opening. In addition, the insulation liner 26 is provided with a channel 31, the channel 31 being arranged to face the tube 30 and to couple said tube 30 with the annular channel 25 arranged around the vapor collection tube 15. The pipe 30 is connected to an inert gas reservoir, not shown, and the installation comprises another pipe, not shown, which is connected to said inert gas reservoir and which opens inside said primary insulating barrier 7, for example in the vicinity of the liquid collecting dome, to create an inert gas circulation loop capable of circulating inert gas inside the primary insulating barrier 7.

Furthermore, as shown in fig. 2, the sheath 19 is not welded to the inner hull 4 of the catamaran hull, providing an annular channel 32 between said sheath 19 and the inner hull 4, which annular channel 32 allows the circulation of the fluid present in the secondary thermal insulation barrier 5 towards the secondary sealed space 33 as shown in fig. 1. A secondary sealed space 33 is radially provided between the annular insulating layer 18 and the outer shaft 9 and is confined in the upper portion of the gas collection dome 1 by sealingly connecting the outer shaft 9 to an annular ring 42 of the vapor collection tube 15.

According to one embodiment, two further tubes, not shown, pass sealingly through the outer shaft 9 in order to open into the secondary sealed space 33. One of the pipes forms part of a secondary drain for protecting the secondary sealing membrane 6 from overpressure that may occur in the secondary insulating barrier 5. To this end, the pipe is connected to a valve which is closed by default and which opens when the pressure inside the secondary insulation barrier 5 exceeds a predetermined threshold. The other tube forms part of a secondary inerting apparatus that allows the inert gas to circulate in the secondary insulating barrier 5.

Fig. 4 shows the structure of a secondary sealing film 6 in the region of the gas collection dome 1. The secondary sealing membrane 6 comprises a metal secondary closure plate 34 in the form of a square. In the secondary closing plate 34, a circular opening 35 is provided, through which circular opening 35 the vapor collection pipe 15 passes, which vapor collection pipe 15 is not shown in fig. 4. The two corrugated metal sheets 36, 37 disposed on either side of the secondary closure plate 34 are cut to provide a slightly smaller opening compared to the secondary closure plate 34. Two corrugated metal sheets 36, 37 are sealingly lap-welded to the secondary closure plate 34.

The central axis of the gas collecting dome 1 is centered in a position corresponding to the intersection between the director lines of the two

perpendicular corrugations

38, 39. The two

corrugations

38, 39 are therefore interrupted at the secondary closing plate 34. For this purpose, the

bellows

38, 39 are sealingly closed by an end piece 40. The other adjacent corrugations are uninterrupted by themselves and pass on either side of the air dome.

The lower annular plate 21 is welded to the closing plate 34 in the central region of the closing plate defined by the corrugations. It will thus be understood that by defining the diameter of the lower portion of the jacket 19, and therefore of the lower annular plate 21, it is possible to interrupt only the two

corrugations

38, 39 of the secondary sealing membrane 6, which allows the loss of elasticity of the secondary sealing membrane 4 in the vicinity of the channels of the gas collecting dome 1 to be limited.

The above described techniques for sealed and insulated vessels may be used in different types of storage, for example in LNG storage in onshore facilities or in floating structures such as LNG tankers or others.

Referring to fig. 4, a cut-away view of an LNG tanker 70 shows a generally prismatic sealed and insulated vessel 71 installed in the double hull 72 of the vessel. The walls of the receptacle 71 include: a primary sealing barrier for contact with the LNG contained in the vessel; a secondary sealing barrier disposed between the primary sealing barrier and the twin hull 72 of the vessel; and two insulation barriers respectively provided between the primary and secondary sealing barriers and between the secondary sealing barrier and the catamaran hull 72.

A loading/unloading pipe 73 provided on the top deck of the ship may be connected to the sea or to a harbour quay by means of suitable connectors in a manner known per se for transferring LNG cargo from or to the container 71.

Fig. 4 shows an example of an offshore terminal comprising a loading and unloading station 75, a subsea pipe 76 and an onshore facility 77. The loading and unloading station 75 is a fixed offshore facility that includes a mobile arm 74 and a tower 78 that supports the mobile arm 74. The moving arm 74 carries a bundle of insulated flexible conduits 79 connectable to the loading/unloading duct 73. The orientable moving arm 74 is adaptable to various forms of LNG containers. A connecting pipe, not shown, extends inside the tower 78. The loading and unloading station 75 allows the LNG vessel 70 to be loaded and unloaded from, or to, an onshore facility 77 that includes a liquefied gas storage vessel 80 and a connection 81 connected to the loading or unloading station 75 through a subsea pipe 76. The subsea pipe 76 allows for long distance (e.g., 5km) liquefied gas transfer between the loading or unloading station 75 and the onshore facility 77 so that the LNG tanker 70 can be kept far offshore in the loading and unloading operations.

To generate the pressure required to transport the liquefied gas, pumps onboard the ship 70, and/or pumps provided with onshore facilities 77, and/or pumps provided with loading and unloading stations 75 may be used.

Although the invention has been described with reference to a number of specific embodiments, it is clear that the invention is not in any way restricted thereto and that the invention comprises all technical equivalents of the means described and combinations thereof as long as they fall within the scope of the invention.

Use of the verbs "comprise", "comprise" and their conjugations does not exclude the presence of elements or steps other than those stated in the claims.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Claims

1. A sealed and insulated container for storing liquefied gas, comprising an upper wall having, in order in a thickness direction: -a secondary thermal insulation barrier (5) resting on a support structure (4), -a secondary sealing film (6) resting on the secondary thermal insulation barrier (5), -a primary thermal insulation barrier (7) resting on the secondary sealing film (6), and-a primary sealing film (8) for contact with the liquefied gas contained in the container, the container further comprising a gas-collecting dome (1) comprising:

-a vapour collection pipe (15) for extracting vapour resulting from the evaporation of the liquefied gas in the container, the vapour collection pipe (15) passing through an opening (11) provided in the support structure (4) and through the upper wall of the container, the vapour collection pipe (15) comprising a peripheral wall sealingly connected to the primary sealing membrane (8);

-a jacket (19) arranged around the vapour collection pipe (15), the jacket (19) comprising a lower end sealingly connected with the secondary sealing membrane (6), the jacket (19) being sealingly connected to the vapour collection pipe by means of an upper annular plate (20) extending transversely between the jacket (19) and the vapour collection pipe (15) so as to provide a sealed primary space (22) between the jacket (19) and the vapour collection pipe (15), the sealed primary space (22) being in communication with the primary insulating barrier (7), the jacket (19) having such a shape between the upper annular plate (20) and the secondary sealing membrane (6): the shape is such that the outer diameter of the sheath (19) tapers towards the secondary sealing membrane (6) between the upper annular plate (20) and the secondary sealing membrane (6); and

-a primary discharge device for discharging fluid from the primary insulating barrier (7), comprising a pipe (27) sealingly connected to the upper annular plate (20) and communicating with the primary insulating barrier (7) through the sealed primary space (22).

2. Sealed and insulated container according to claim 1, wherein the jacket (19) has, between the upper annular plate (20) and the secondary sealing membrane (6), a first frustoconical portion (43) tapering towards the secondary sealing membrane (6).

3. The sealed and insulated container according to claim 1 or 2, wherein the gas collecting dome (1) comprises an insulating liner (26) arranged in the sealed primary space provided between the jacket (19) and the vapor collection pipe (15), a channel (29) being provided in the insulating liner (26) connecting the pipe (27) to the primary insulating barrier (7).

4. A sealed and insulated container according to claim 3, wherein the secondary sealing membrane (6) has a first opening (35), the vapor collection tube (15) passing through the first opening (35), the first opening (35) having a diameter larger than the diameter of the peripheral wall of the vapor collection tube (15) so as to provide an annular channel (25) between the peripheral wall of the vapor collection tube (15) and the secondary sealing membrane (6) coupling the sealed primary space (22) and the primary insulating barrier (7).

5. A sealed and insulated container according to claim 4, wherein the jacket (19) has a lower end welded to a lower annular plate (21), the lower annular plate (21) being welded to the secondary sealing membrane (6) and having a second opening (24), the vapor collection tube (15) passing through the second opening (24), and the diameter of the second opening (24) being greater than the diameter of the peripheral wall of the vapor collection tube (15), thereby coupling the sealed primary space (22) and the primary insulating barrier (7).

6. A sealed and insulated container according to claim 4, wherein the channel (29) is provided in the insulating liner (26) such that from the tube (27) of the primary drain towards the annular channel (25), the channel (29) converges towards the vapour collection tube (15).

7. The sealed and insulated container according to claim 1 or 2, wherein the upper annular plate (20) is positioned above the support structure (4).

8. The sealed and insulated container according to claim 1 or 2, wherein the pipe (27) of the primary discharge device is welded to the periphery of an opening provided in the upper annular plate (20).

9. A sealed and insulated container according to claim 1 or 2, wherein the pipe (27) of the primary discharge device is connected to a valve which can be opened when the pressure in the primary insulating barrier (7) is greater than a threshold pressure.

10. A sealed and insulated container as claimed in claim 1 or 2, wherein the secondary sealing membrane (6) comprises a plurality of corrugated metal sheets (34, 36, 37) sealingly welded together, and each corrugated metal sheet comprises at least two perpendicular corrugations.

11. Sealed and insulated container according to claim 10, wherein the gas collection dome (1) has a central axis, wherein the two director lines of the two central corrugations (38, 39) of the secondary sealing membrane (6) perpendicular to each other intersect at the central axis of the gas collection dome (1).

12. A sealed and insulated container according to claim 11, wherein each of the two central corrugations (38, 39) is disposed between two adjacent corrugations, the two adjacent corrugations of each of the two central corrugations (38, 39) defining a perimeter inside which the sheath (19) is sealingly connected to the secondary sealing membrane (6).

13. The sealed and insulated container of claim 1 or 2, wherein the gas collection dome (1) comprises an outer shaft (9) disposed around the vapor collection tube (15) and the jacket (19) and hermetically welded to the support structure (4).

14. A vessel (70) for transporting fluids, the vessel comprising a double hull (72) comprising an inner hull forming the support structure of the container, and a container (71) according to any one of claims 1 to 13 provided in the double hull.

15. Method for loading or unloading a vessel (70) according to claim 14, wherein the fluid is transported from a floating or onshore storage facility (77) to the vessel (71) of the vessel or from the vessel (71) of the vessel to a floating or onshore storage facility (77) through insulated pipelines (73, 79, 76, 81).

16. A transfer system for a fluid, the system comprising: a vessel (70) according to claim 14; isolation piping (73, 79, 76, 81) arranged to connect the vessels (71) installed in the hulls of the vessel to a floating or onshore storage facility (77); and a pump for transferring fluid from a floating or onshore storage facility to the vessel of the vessel or from the vessel of the vessel to a floating or onshore storage facility through the insulated pipeline.