KR20190020317A - Gas Dome Structures for Sealed Insulated Vessels - Google Patents

Abstract

The present invention relates to a gas dome structure for a closed and insulated tank arranged inside a double hull defined by an inner hull and an outer hull.
An external drum capable of passing through two openings provided for the outer hull and inner hull respectively,
An inner drum which extends inside the outer drum, is fixed to the outer drum and comprises a peripheral wall intended to be intimately connected to the sealing membrane and
An intermediate insulation gap arranged between the inner drum and the outer drum,
The outer drum comprises first and second collars each projecting radially outwardly from the outer drum to be welded to the outer hull around the opening provided in the outer hull and to the inner hull around the opening provided in the inner hull, respectively. .

Description

Gas Dome Structures for Sealed Insulated Vessels

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

Closed adiabatic tanks are used especially for storing liquefied natural gas (LNG) which is stored at atmospheric pressure at about -162 ° C.

More particularly, the present invention relates to a gas dome structure intended to define a path for steam to flow between an interior space of a tank and a steam header arranged outside the tank.

Document KR20140088975 discloses a hermetically sealed and insulated tank containing a gas dome structure which is housed inside a double hull of a vessel and is intended to define a path for steam to flow between the inner space of the tank and two steam headers arranged outside the tank. do.

The gas dome structure passes through the outer hull of the double hull and is welded to the inner hull of the double hull, between the inner drum and the inner and outer drum extending inside the outer drum and tightly connected to the primary sealing membrane of the tank. An intermediate insulation gap arranged. The outer drum includes an assembly flange for receiving an removable cover having a sealing portion interposed therebetween, at its upper end, with an outwardly bent edge. The inner drum and the intermediate insulation gap do not extend to the top of the outer drum, and two pipes for collecting gas in the vapor pass radially through the outer drum in the upper region of the outer drum, above the inner drum and the intermediate insulation gap. .

Such gas dome structures are not completely satisfactory. In fact, in terms of configuration, these gas dome structures must be assembled in place on the ship, which complicates the assembly work and takes more time.

Furthermore, the sealing portion interposed between the removable cover and the assembly flange is in direct contact with the vapor state contained in the inner drum. However, when the fluid stored in the tank is a cryogenic fluid, such as liquefied gas, the vapor is likely to be very cold, about -160 ° C. Therefore, the sealing portion also tends to be relatively low temperature, which is likely to damage the sealing portion and cause leakage of the gas dome. Therefore, the reliability of this gas dome is not completely satisfactory.

One idea inherent in the present invention is to propose a gas dome structure that is simple to assemble.

According to one embodiment, a gas dome structure for a closed and insulated tank arranged inside a double hull defined by an inner hull and an outer hull, the gas dome structure having at least one thermal barrier seated at the double hull and the inner hull. And through a ceiling wall of the tank comprising a sealing membrane intended to be in contact with the fluid contained in the tank, to provide a path for the steam to flow between the inner space of the tank and at least one vapor header arranged outside the tank. Intended, the gas dome structure is

An external drum capable of passing through two openings provided for the outer hull and inner hull respectively,

An inner drum which extends inside the outer drum, is fixed to the outer drum, is open to communicate with the inner space of the tank, and includes a peripheral wall intended to be intimately connected to the sealing membrane;

An intermediate insulation gap arranged between the inner drum and the outer drum,

The outer drum comprises first and second collars each projecting radially outwardly from the outer drum to be welded to the outer hull around the opening provided in the outer hull and to the inner hull around the opening provided in the inner hull, respectively. Provide a gas dome structure.

Thus, by the two said collars, the gas dome structure can be partially or fully pre-assembled in the workshop, and the gas dome structure can be easily assembled at the double hull.

According to an embodiment, such a gas dome structure may include one or more of the following features.

According to one embodiment, the gas dome structure is a preassembled structure.

According to one embodiment, the second collar intended to be closely welded to the inner hull has a diameter smaller than the first collar.

According to one embodiment, the outer drum and the inner drum each have a top, the top ends in the same horizontal plane, are tightly connected together by an assembly flange, and the gas dome structure is attached to the assembly flange by an attachment member. A cover and an annular sealing compressed between the cover and the assembly flange. In this configuration, therefore, the intermediate insulation gap extends to the assembly flange, which helps to further insulate the seal and limit the risk of leakage.

According to one embodiment, the assembly flange comprises a radially outwardly extending exterior of the outer drum, the attachment member passing through a hole provided in the exterior of the assembly flange.

According to one embodiment, the cover includes an inner surface facing towards the inner drum, the inner surface having a protrusion made of an insulating material that engages the inner drum. This also helps to insulate the sealing.

According to one embodiment, the gas dome structure further comprises a steam collection pipe suitable for carrying steam between an inner drum of the inner drum and a steam header arranged outside the tank, the vapor collecting pipe further comprising an outer drum, an intermediate insulating gap and Passes through the inner drum in a radially closed manner and is opened inside the inner drum.

According to one embodiment, the gas dome structure includes an insulating sleeve passing radially sealed through the outer drum, the intermediate insulating gap and the inner drum, and the vapor collection pipe passes through the insulating sleeve and sealed.

According to one embodiment, the insulating sleeve comprises two coaxial cylindrical walls which are closely connected together and spaced apart from each other by an annular gap, the insulating sleeve being opened inside the annular gap to vacuum the annular gap under vacuum. A sealable connector suitable for connection to the pump.

According to one embodiment, the steam collection pipe has a bend arranged inside the inner drum and comprises a lower portion oriented parallel to the inner drum towards the inner space of the tank.

According to one embodiment, the gas dome structure further comprises a support device for supporting the lower part of the vapor collection pipe and arranged to distribute the force exerted therein around the inner circumference of the inner drum.

According to one embodiment, the support device is a first annular plate attached to the inner drum and projecting radially toward the inside of the inner drum, attached to the bottom of the steam collection pipe and radially outward of the bottom of the steam collection pipe. A plurality of support arms, each of which includes a first end attached to the first annular plate and a second end attached to the second annular plate, distributed at regular intervals around the lower portion of the vapor collecting pipe and the second annular plate protruding into the It includes.

According to one embodiment, the bottom of the steam collection pipe is provided with a filter.

According to one embodiment, the steam collection pipe is connected to a 3-way connection arranged outside the outer drum.

According to one embodiment, the inner drum and the outer drum comprise a bellows region which helps to allow them to shrink or expand under the influence of temperature differences.

According to one embodiment, the intermediate insulation gap is filled with a gaseous state and / or insulation lining disposed under vacuum. Advantageously the insulating lining comprises at least one insulating material selected from glass wool, rock wool, cotton wool, fiber-like material, pearlite, expanded pearlite, polymer foam and aerogels.

According to one embodiment, the intermediate insulating gap has a bottom tightly closed by an annular flange.

According to one embodiment, the invention is a fluid storage device comprising a closed and insulated tank arranged at a double hull and a double hull defined by an inner hull and an outer hull, wherein the tank is

A thermal barrier seated at the inside hull,

Sealing membranes intended to be in contact with the fluid contained in the tank and

A gas dome structure as described above passing through an outer hull, an inner hull, an insulating barrier and a sealing membrane to provide a path for the steam to flow between the inner space of the tank and at least one vapor header arranged outside the tank and,

The first collar of the gas dome structure is welded to the outer hull around the opening provided in the outer hull, the second collar of the gas dome structure is welded to the inner hull around the opening provided in the inner hull and the inner drum is intimately connected to the sealing membrane. It provides a fluid storage device to be connected.

According to an embodiment, such a fluid storage device may include one or more of the following features.

According to one embodiment, the opening provided in the inner hull has a smaller diameter than the opening provided in the outer hull and the second collar has a diameter smaller than the opening provided in the outer hull and larger than the opening provided in the inner hull. This configuration allows the gas dome structure to pass easily through the double hull, thereby ensuring that the gas dome structure is easily installed.

According to one embodiment, the insulating barrier is a secondary insulating barrier, the sealing membrane is a primary sealing membrane, and the tank is arranged between the secondary sealing membrane and the secondary sealing membrane and the primary sealing membrane seated on the secondary insulating barrier. It further comprises a primary insulating barrier.

According to one embodiment, the outer drum comprises a third collar that projects radially outwardly of the outer drum and is intimately connected to the secondary sealing membrane.

According to one embodiment, the gas dome structure further comprises an additional drum radially extending outside the outer drum and having an upper end welded to the first collar and an upper end welded to the second collar, the insulating lining further comprising the additional drum and the outer end. Are arranged between drums.

According to one embodiment, the intermediate insulating gap arranged between the inner drum and the outer drum is divided into a primary compartment and a secondary compartment, which are sealed to each other.

According to one embodiment, the primary compartment and the secondary compartment are separated by a closed annular partition attached to the outer drum and the outer drum.

According to one embodiment, the primary compartment has one or more ports intended to be provided in the outer drum so that the primary compartment is in communication with the primary thermal barrier.

Such a fluid storage device may be part of a land storage facility for storing LNG, for example, or may be a coastal or deep sea offshore structure, in particular a VLEC vessel or LNG carrier, an offshore storage and regasification unit (FSRU), a remote offshore production storage and unloading unit ( FPSO) or other applications. In the case of offshore structures, the tank may be intended to contain liquefied natural gas that acts as a fuel for propulsion of offshore structures.

According to one embodiment, the fluid storage device is configured in the form of a ship.

According to one embodiment, the fluid storage device is configured in the form of a ship.

According to one embodiment, the present invention provides a method for loading or unloading such a storage device, which includes conveying fluid from an offshore or onshore storage facility to an tank of the storage device via an insulated pipe and vice versa. .

According to one embodiment, the invention relates to a transmission system for a fluid, the system from a sea or onshore storage facility to a tank via an insulated pipe and an insulated pipe arranged to connect the tank to the storage device, offshore or onshore storage facility described above. Or vice versa, a system comprising a pump for sending a flow of fluid.

Another idea inherent in the present invention is to propose a particularly reliable gas dome structure, in particular helping to limit vapor leakage.

To this end, according to one embodiment, the invention is a gas dome structure for a closed and insulated tank arranged inside a double hull defined by an inner hull and an outer hull, wherein the gas dome structure is seated at a double hull and an inner hull. Passing through a ceiling wall of a tank comprising at least one thermal barrier and a sealing membrane intended to be in contact with the fluid contained in the tank, allowing steam to flow between the interior space of the tank and at least one vapor header arranged outside the tank Is intended to provide a path for the gas dome structure

An external drum capable of passing through two openings provided for the outer hull and inner hull respectively,

An inner drum which extends inside the outer drum, is fixed to the outer drum, is open to communicate with the inner space of the tank, and includes a peripheral wall intended to be intimately connected to the sealing membrane;

An intermediate insulation gap arranged between the inner drum and the outer drum,

The outer drum and the inner drum each have a top,

The steam collecting pipe passes radially sealed through the outer drum, the intermediate insulation gap and the inner drum, and is opened inside the inner drum,

The ends end in the same plane and are tightly connected together by an assembly flange, the intermediate insulation gap extends to the top of the inner and outer drums, and the gas dome structure is connected with the cover and the cover attached to the assembly flange by an attachment member. It provides a gas dome structure further comprising an annular sealing portion compressed between the assembly flange.

By this arrangement, the intermediate insulation gap extends to the assembly flange, which helps to further insulate the sealing and limit the risk of leakage.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood from the following description of several specific embodiments of the invention, which are merely illustrative and are not restrictive of examples, with reference to the accompanying drawings, in addition, the objects, details, features, and advantages become more apparent. will be.

1 is a perspective view of a gas dome structure passing through a double hull of a vessel and a closed and insulated tank seated at an internal hull of a double hull.
2 is a cross-sectional view of the gas dome structure of FIG. 1.
3 is an enlarged cross sectional view of a region in which a pipe for collecting gas in a vapor passes through an outer drum, an inner drum and an intermediate insulation gap;
4 is a perspective cross-sectional view of the gas dome structure of FIG. 1 passing through openings provided in the inner hull and outer hull.
5 is a perspective cross-sectional view of a support device for supporting a pipe for collecting the gas in the vapor state in a filter having a pipe for collecting the gas in the vapor state and an internal drum of the gas dome structure.
6 is a schematic cutaway view of a tank of an LNG carrier and a terminal for loading / unloading the tank.
7 is a partially cutaway perspective view of the wall of a sealed and insulated tank.
8 is a partial cross-sectional view of the gas dome structure according to the second embodiment.
9 is a partial sectional view of a gas dome structure according to the third embodiment.

Referring to FIG. 1, the figure shows a gas dome structure 1 for a closed and insulated tank for storing liquefied gas, such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG). The gas dome structure 1 defines a path for steam to flow between the inner space 2 of the tank and one or more vapor headers 3, 48 arranged outside the tank.

The tank is arranged inside a double hull of a ship comprising an outer hull 4 and an inner hull 5. The inner hull 5 forms the bearing structure of the tank. The tank generally has a polyhedron shape.

Referring to FIG. 7, a multilayered structure of a wall of a sealed and insulated tank according to one embodiment will be described. Each wall of the tank is stored in the secondary insulation barrier 6, the secondary sealing membrane 7, the primary insulation barrier 8 and the tank, which are seated at the inner hull 5 from the outside to the inside in the thickness direction of the tank. A primary sealing membrane 9 intended to be in contact with the fluid.

The primary insulation barrier 8 and the secondary insulation barrier 6 each consist of an insulation element, more particularly a cuboid insulation box 10 arranged next to each other in a regular pattern. Each thermal insulation box 10 includes a base panel 11 and a cover panel 12. The side panel 13 and the inner web 14 extend between the base panel 11 and the cover panel 12 in the thickness direction of the tank wall. The base and cover panels 11, 12 and the inner web 14 define a space in which a thermal insulation lining, for example expanded pearlite, is installed. Each insulation box 10 is fixed to the inner hull 5 by an anchoring member. The thermal insulation box 10 of the primary thermal insulation barrier 8 and the secondary thermal insulation barrier 6 provides a primary membrane 9 and a secondary membrane 7, respectively.

The secondary and primary membranes 7, 9 each consist of a series of parallel strikes 15 made of Invar®, having bent edges, alternatingly arranged with an extended weld support 16 made of Invar®. The strike 15 comprises in the width direction a planar center strip and lateral bent edges seated on the cover panel 12 of the thermal insulation box 10. The bent edge extends substantially perpendicular to the planar center strip. The bent edge of the strike 15 is closely welded to the weld support 16. Each weld support 16 is secured to the thermal insulation barriers 6, 8 below it, for example by being housed in an inverted T-shaped groove provided in the cover panel 12 of the thermal insulation box 10.

At the corner between the two walls, the secondary and primary membranes 7, 9 of the two walls are connected by a connecting ring 17 in the form of a tube with a rectangular cross section. The connecting ring 17 forms a structure that helps to bear the tensile forces resulting from heat shrinkage of the secondary and primary membranes 7, 9, deformation of the hull and movement of the cargo.

With reference to FIGS. 2 and 4, a gas dome structure 1 passing through two openings 18, 19 provided in the outer hull 4 and the inner hull 5, respectively, is described. The gas dome structure 1 comprises a cylindrical outer drum 20 passing through an opening 18 of the outer hull 4 and an opening 19 of the inner hull 5. The outer drum 20 is open at both ends. The outer drum 20 has two collars 21, 22 to attach the gas dome structure 1 to the outer hull 4 and the inner hull 5, respectively. The collars 21, 22 are welded to the outer drum 20 and protrude radially outward with respect to the axis of the outer drum 20. As shown in FIG. 4, the collar 22 intended to be attached to the inner hull 4 has an outer diameter smaller than that of the opening 18 provided in the outer hull 4 so that the gas dome structure 1 can be installed. When passing through the opening 18 of the outer hull 4. Only the outer diameter of the collar 22 is larger than that of the opening 19 provided in the inner hull 5. The collar 22 can thus be welded closely to the inner hull 5 around the opening 19. The outer collar 21 is intended to be closely welded to the outer hull 4 around the opening 18 provided in the outer hull 4, for this purpose having a larger outer diameter than that of the opening 18.

The gas dome structure 1 further includes an inner drum 23 attached to the outer drum 20. The inner drum 23 is formed of a cylindrical circumferential wall that is open at both ends thereof. The inner drum 23 extends inside thereof coaxially with the outer drum 20. Thus, an insulating insulating gap 24 is provided between the outer drum 20 and the inner drum 23. The inner drum 23 extends to the top of the outer drum 20, and the top of the outer and inner drums 23, 20 are closely connected together by an assembly flange 25 that is substantially horizontal. The assembly flange 25 comprises an outer projecting radially outward from the inner and outer drums 20 connecting the ends of the outer and inner drums 20, 23.

2 and 4, at least one bellows region allows the outer drum 20 and the inner drum 23 to expand or contract depending on whether or not liquefied gas vapor is contained in the gas dome structure 1. And 31 and 32, respectively.

In one embodiment, either of the collars 21, 22 to compensate for the placement of the collars 21, 22 relative to the hulls 4, 5 and / or the tolerance of the relative position of the hulls 4, 5. And / or the remainder, in particular the collar 21, may be welded to a half moon shaped shim first welded to each hull 4, 5 around the openings 18, 19. The thickness of the shims is sized to ensure contact between the collars 21, 22 and each shim and between the shims and the angles 4, 5.

Alternatively, the bellows regions 31, 32 each have an additional length which, when installed, allows the structure of the dome, in particular the inner and outer drums 23, 20, to be compressed, which compression effect is the cooling of the tank 2. Is reduced or substantially eliminated during heat shrinkage caused by For this purpose, two compressions can be used to compress the bellows regions 31, 32 by pressing the collar 21 on the hull 4 when welding the collar 21 to the hull 4.

The gas dome structure 1 further comprises a removable cover 26, allowing access to the tank through the gas dome structure 1, in particular for tank maintenance and inspection work. The cover 26 has a hooking member 27 on its upper surface which allows it to be operated by a handling tool. The cover 26 is seated in the assembly flange 25 and passes through a hole provided around the cover and a hole provided outside the assembly flange 25, respectively, in particular a plurality of attachment members 28 shown in FIGS. 1 and 4. Attached). Attachment member 28 consists of, for example, a bolt comprising a threaded rod and a nut cooperating with the threaded rod.

Seals (not shown) are compressed between the cover 26 and the assembly flange 25 to help provide a sealing force between the outside and the inside of the inner drum 23. The sealing part is arranged, for example, between a cover 26 and a diameter smaller than the diameter on which the attachment member is installed, ie the assembly flange 25. According to a variant (not shown), the sealing portion (s) are arranged in a recess or assembly flange 25 provided in the cover 26. The sealing portion can be flat or toric.

The sealing part consists of a polymer such as butadiene acrylonitrile (NBR), polyterrafluoroethylene (PTFE), for example reinforced with glass and / or aramid and / or carbon fiber by Klingersil®. Due to the configuration described above, in particular the fact that the intermediate insulating gap 24 extends to the assembly flange 25, the sealing part is satisfactorily insulated, which helps to limit the risk of damage to the sealing part and the risk of leakage. give.

Further, as shown in FIGS. 2 and 4, the cover 26 includes a protrusion 33 made of an insulating material engaged with the inner drum 23 on its inner surface facing toward the inner side of the inner drum 23. The protrusion 33 made of an insulating material has a diameter slightly smaller than that of the inner drum 23. This configuration also helps to insulate the sealing. The protrusion 33 made of an insulating material is made of a particularly rigid or flexible insulating foam such as polyurethane foam or melamine.

Also at the bottom, the inner drum 23 and the outer drum 20 are closely connected to each other so that the intermediate insulating gap 24 provided between the inner drum 23 and the outer drum 23 is sealed. For this purpose, an annular flange 29 is closely welded between the bottom edge of the inner drum 23 and the outer drum 20.

The outer drum 20 and the inner drum 23 pass through the tank's ceiling wall, i.e., through the secondary and primary insulating barriers 6 and 8 and the secondary and primary membranes 7, 9 and open inside the tank. do. As schematically shown in FIG. 2, the inner drum 23 and the outer drum 20 extend up to the primary membrane 9 of the ceiling wall of the tank. The primary membrane 9 is intimately connected to the annular flange 29, providing a hermetic continuity of the primary membrane 9. In addition, the secondary membrane 7 is closely welded to the outer drum 20, providing a sealing continuity of the secondary membrane 7 between the primary and secondary insulating barriers 8, 6. To this end, according to one embodiment, the outer drum 20 protrudes radially outward from the outer drum 20 to form a suitable support to allow the secondary membrane 7 to be welded to the outer drum 20, It has a third annular collar 30 schematically shown in FIG. In an embodiment not shown, the inner drum 23 and the outer drum 20 extend into the primary membrane 9 of the ceiling wall of the tank, with the primary membrane 9 facing outward of the outer drum 23. It is closely welded to an additional annular collar (not shown) projecting in the radial direction.

In the illustrated embodiment, the intermediate insulating gap 24 is filled with an insulating lining 34 evenly distributed on the inner surface of the outer drum 20, between the outer drum 20 and the inner drum 23. Insulating lining 34 includes one or more insulating materials selected from glass wool, rock wool, cotton wool, fiber-like material, pearlite, expanded pearlite, polymer foam and aerogels. In the illustrated embodiment, the insulating lining 34 has a recess 46 in the region corresponding to the bellows region 32 of the inner drum 23 to allow the bellows region 32 to be received.

In another embodiment, the intermediate insulation gap 24 is disposed in a vacuum. In this embodiment, the gas dome structure 1 passes through the inner drum 23 or the outer drum 20 and is opened inside the intermediate insulation gap 24, which is arranged to place it in a vacuum state. Is provided with a sealable connector suitable for connection to a vacuum pump allowing gas present in In another embodiment, the two embodiments described above are combined such that the intermediate insulating gap 24 is filled with an insulating lining 34 and placed in a vacuum.

The gas dome structure 1 passes through the outer drum 20, the inner drum 23 and the intermediate insulating gap 24 in a radially sealed manner, and includes a steam header disposed inside the inner drum 23 and outside the tank. It further comprises one or more vapor collection pipes 35 for transporting steam between 3, 48. The vapor collection pipe 35 therefore does not pass through the cover 26, which helps simplify the process of removing and engaging the cover 26 when the operator needs to access the inside of the tank.

More specifically, the steam collection pipe 35 penetrates through the insulating sleeve 37 shown in detail in FIG. 3, passing radially through the outer drum 20, the inner drum 23 and the intermediate insulation gap 24. Pass through the enclosure. The insulating sleeve 37 comprises two coaxial cylindrical walls which are tightly connected together and spaced apart from each other by an annular gap disposed in vacuum. For this purpose, the insulating sleeve 37 comprises a sealable connector 38 which is open on the inside of the annular gap and is intended to be connected to a vacuum pump to place the annular gap in a vacuum.

Although in the preferred embodiment shown, a single vapor collection pipe 35 passes radially hermetically through the outer and inner drums 20, 23, the gas dome structure is the outer and inner drums 20, 23. It may also comprise a plurality of vapor collection pipes 35 passing through and closed in a radial direction.

2 and 4 show that the vapor collecting pipe 35 is bent such that the vapor collecting pipe 35 has a lower portion 36 oriented parallel to the axes of the inner and outer drums 23, 20 toward the inner space of the tank. It shows having a part. The bend and lower portion 36 are detachably attached to the remainder of the steam collection pipe 35 by, for example, a bolted assembly flange. Thus, the bends and bottoms 36 may be disassembled to allow people or equipment to pass through this gas dome structure 1.

The gas dome structure 1 supports the bottom 36 of the vapor collection pipe 35 and is arranged to distribute the force exerted on the bottom 36 around the inner circumference of the inner drum 23, in particular FIGS. 2, 4. And a support device 39 as shown in FIG. 5. To this end, the support device 39 is attached to the inner drum 23 and radially outwardly of the first annular plate 40, the vapor collection pipe 35, which projects radially toward the inside of the inner drum 23. A second annular plate 41 attached to the lower portion 36 of the vapor collecting pipe 35 protruding in a direction and, for example, bolted and attached between the first annular plate 40 and the second annular plate 41, respectively. And a plurality of arms 42 distributed at regular intervals around the lower portion 36 of the steam collection pipe 35. Furthermore, as shown in FIGS. 2 and 5, the first annular plate 40 is advantageously supported by a support bracket 43 made of sheet metal welded to the inner drum 23 and the lower surface of the first annular plate 40. do.

In the embodiment shown in FIG. 2, the gas dome structure 1 is arranged in the intermediate insulation gap 24 and an anchoring tab welded between the inner drum 23 and the outer drum 20 at the support bracket 43 attaching region ( 49). The purpose of this anchoring tab 49 is to bear some of the force supporting the vapor collection pipe 35 on the outer drum 20, especially when the thickness of the inner drum 20 does not have sufficient mechanical strength.

The lower portion 36 of the steam collection pipe 35 further has a filter 44 which provides headloss to prevent the liquid gas from returning to the steam header 3 and leaving the tank.

The gas dome structure 1 passes through the outer drum 20, the intermediate insulation gap 24 and the inner drum 23 above the outer hull 4 and descends along the inner drum 23 to open into the inner space of the tank. At least one pipe 45 for supplying the liquefied gas, in particular shown in FIGS. 2 and 4. In the inner space of the tank, the pipe 45 has a plurality of injection nozzles which can spray liquid gas to cool the vapor state of the gas stored in the tank to limit the decrease in the vapor pressure of the inner space of the tank.

As shown in FIG. 1, the steam collection pipe 35 is connected to a three-way connection 47 leading to two separate steam headers 3, 48, outside the gas dome structure 1. One of the steam headers 48 has a safety valve (not shown). The safety valve is adjusted to ensure that the gas in the vapor state is discharged from the tank when the tank's vapor pressure is higher than the reference pressure of 0 to 2 bar, such as 0.2 to 0.4 bar. In particular, since the head loss is caused by the bent region and the filter 44, the safety valve is adjusted to a pressure slightly lower than the reference pressure at which the steam pressure of the tank should not be exceeded. This steam header 48 may be used to withdraw steam from the tank in case of overpressure, and is intended to control the pressure inside the tank to prevent overpressure which is likely to damage the tank.

For example, such a steam header 48 carries steam to a vent mast, burner, ship propulsion device, or a liquefaction device where the gas in the vapor state is liquefied and reintroduced into the tank in liquid state. The purpose of the other steam header 3 is to allow steam to flow during the operation of loading and unloading the tank. Specifically, when liquefied gas is transferred from the supply terminal to the tank during the loading operation, the gaseous gas is simultaneously transferred from the tank to the terminal via the gas dome structure 1 and the steam header 3, so that the pressure of the gas blanket of the tank Keep substantially constant. In contrast, during an unloading operation in which liquefied gas is transferred from the tank to the terminal, the gaseous gas is simultaneously transferred from the terminal to the tank to prevent a decrease in pressure in the tank.

The outer drum 20, the inner drum 23, the collars 21 and 22, the support device 29 and the vapor collecting pipe 35 are made of a metallic material, for example iron alloy or stainless steel containing manganese or nickel. .

8 shows a gas dome structure 1 according to a second embodiment. This gas dome structure 1 differs from the gas dome structure described above in that it further comprises an additional insulation barrier 50 between the two collars 21, 22. For this purpose, the gas dome structure 1 comprises an additional drum 51 extending radially outside the outer drum 20. The additional drum 51 comprises a lower end welded to the collar 22 and an upper end welded to the collar 21. The additional drum 51 has a diameter smaller than that of the collars 21, 22. More specifically, the diameter of the additional drum 51 is formed such that each collar 21, 22 has an annular surface intended to be welded to one of the hulls, about its outer circumference, of sufficient size to obtain a satisfactory weld. do.

In the illustrated embodiment, the additional drum 51 has a bellows region 52 that allows the additional drum 51 to expand or contract. Furthermore, the gap provided between the outer drum 20 and the additional drum 51 may include an insulating lining comprising at least one insulating material selected from glass wool, rock wool, cotton wool, fiber-like material, pearlite, expanded pearlite, polymer foam and aerogel. 53). The additional drum 51 and insulating lining 53 are preassembled to the gas dome structure 1 in the workshop, before being assembled at the ship's double hull. This configuration helps to increase the thermal insulation performance of the gas dome structure 1, especially in the space located between the two hulls 4, 5. Furthermore, the additional drum 51 is intimately connected to the collars 21, 22 so that the additional drum 51 forms an additional sealing barrier suitable for preventing natural gas from entering the region located between the two hulls 4, 5. Is welded.

9, this figure shows a gas dome structure 1 according to a third embodiment. This embodiment is divided into two compartments, the primary compartment 24a and the secondary compartment 24b, in which the intermediate insulating gap 24 arranged between the inner drum 23 and the outer drum 20 is sealed against each other. This is different from the embodiment of FIG. 8 described above. This configuration provides a gas dome structure with an additional level of seal. For this purpose, the gas dome structure 1 is welded closely to the inner periphery closely welded to the inner drum 23 and to a portion of the outer drum 20 disposed between the hull 5 and the secondary sealing membrane 7. An annular partition 54, for example made of metal, having a defined outer perimeter. In the embodiment shown, the annular partition 54 extends in the secondary sealing membrane 7. The secondary compartment 24b is filled with an insulating lining comprising at least one insulating material selected from glass wool, rock wool, cotton wool, fiber-like material, pearlite, expanded pearlite, polymer foam and aerogel, or to be placed in a vacuum state. It is suitable for connection to a vacuum pump. Primary partition 24a is also filled with an insulating lining comprising one or more of the aforementioned insulating materials.

Moreover, in the illustrated embodiment, the outer drum 20 includes one or more ports 55 that allow the primary partition 24a to communicate with the primary thermal barrier barrier 8. Thus, the primary partition 24a may be coplanar with the inert gas simultaneously with the primary thermal barrier 8 and the possibility of leakage of the primary and / or secondary membranes may be analyzed by analyzing the gas present in the primary thermal barrier. It can be connected to the sensing device for detecting the presence of.

The technique described above for providing a gas dome structure can be used in other types of membrane tanks, onshore facilities or offshore structures such as LNG carriers or elsewhere.

Referring to FIG. 6, a cutaway view of an LNG carrier 70 shows a generally prismatic, sealed and insulated tank 71 mounted to a double hull 72 of a vessel. The walls of the tank 71 are arranged between the primary membrane, the primary membrane and the secondary membrane 72 of the ship and the primary membrane and the secondary membrane and the secondary membrane, which are intended to be in contact with the LNG contained in the tank. Two insulating barriers each arranged between the membrane and the double hull 72.

In a manner known per se, the loading / unloading pipe 73 arranged on the upper deck of the ship may be connected to the water or port terminal by a suitable connector for transferring cargo of LNG to or from the tank 71. .

6 shows an example of a water terminal including a loading and unloading station 75, an underwater pipe 76, and an onshore facility 77. The loading and unloading station 75 is a stationary coastal facility that includes a mobile arm 74 and a tower 78 supporting the mobile arm 74. The movable arm 74 has a series of insulated flexible pipes 79 that can be connected to the loading / unloading pipes 73. The directional movable arm 74 is shaped for LNG carriers of all sizes. The connecting pipe (not shown) extends to the tower 78. The loading and unloading station 75 allows the LNG Carrier 70 to be loaded and unloaded to or from the land installation 77. It comprises a connecting pipe 81 connected to the loading and unloading station 75 by a liquefied gas storage tank 80 and an underwater pipe 76. The submersible pipe 76 allows liquefied gas to be transferred between the loading and unloading station 75 and the land installation 77 over a long distance, such as 5 km, which causes the LNG carrier 70 to be loaded during the loading and unloading operation. Allow to stay at a distance from the shore.

In order to generate the pressure necessary to deliver the liquefied gas, a pump installed in the vessel 70 and / or a pump provided in the land installation 77 and / or a pump provided in the loading and unloading station 75 are used. .

Although the present invention has been described with respect to some specific embodiments, it is obvious that the present invention is not limited thereto, which includes all technical equivalents of the described means and combinations thereof, as long as they fall within the context of the present invention.

The use of the verb “comprises” or “consists of” and its conjugations does not exclude the presence of elements or steps other than those disclosed in a claim.

The use of reference signs between parentheses in the claims shall not be construed as limitations on the claim.

Claims (25)

A gas dome structure (1) for a closed and insulated tank arranged inside a double hull defined by an inner hull (5) and an outer hull (4), the gas dome structure (1) having a double hull and an inner hull (5). Steam passes through the interior wall of the tank and outside the tank, passing through the ceiling wall of the tank comprising at least one insulating barrier 6 seated in the tank and a sealing membrane 9 intended to contact the fluid contained in the tank. Intended to provide a path for flow between the at least one vapor header 3, 48, the gas dome structure 1 being
An external drum 20 which can pass through two openings 18, 19 provided in the outer hull 4 and the inner hull 5, respectively;
An inner drum which extends inside the outer drum 20, is fixed to the outer drum 20, is open to communicate with the inner space of the tank and comprises a peripheral wall intended to be intimately connected to the sealing membrane 9. 23 and
An intermediate insulating gap 24 arranged between the inner drum 23 and the outer drum 20,
The outer drum 20 protrudes radially outwardly from the outer drum 20, so that the opening provided in the outer hull 4 and in the inner hull 5 around the opening 18 provided in the outer hull 4. 19) Gas dome structure (1) comprising first and second collars (21, 22), respectively suitable for being welded to the inner hull (5) in the periphery. The method of claim 1,
The second collar 22, which is intended to be closely welded to the inner hull 5, has a diameter smaller than the first collar 21. The method according to claim 1 or 2,
The outer drum 20 and the inner drum 23 each have a top,
The top ends in the same horizontal plane, are tightly connected together by an assembly flange 25,
The gas dome structure 1 comprises a cover 26 attached to the assembly flange 25 by an attachment member 28 and an annular sealing portion compressed between the cover 26 and the assembly flange 25. (One). The method of claim 3,
The assembly flange 25 includes a radially outwardly projecting exterior of the outer drum 20,
The attachment member (28) passes through a hole provided in the exterior of the assembly flange (25). The method according to claim 3 or 4,
The cover 26 includes an inner surface facing toward the inner side of the inner drum 23,
The inner surface has a gas dome structure (1) having a protrusion (33) made of an insulating material for engaging the inner drum (23). The method according to any one of claims 1 to 5,
Further comprising a steam collection pipe 35 suitable for conveying steam between the steam headers 3, 47 and the inside of the inner drum 23,
The vapor collection pipe 35 passes through the outer drum 20, the intermediate insulation gap 24, and the inner drum 23 in a hermetically sealed manner, and is open to the inside of the inner drum 23. (One). The method of claim 6,
An insulating sleeve 37 passing through the outer drum 20, the intermediate insulating gap 24 and the inner drum 23 in a radially sealed manner,
A vapor dosing pipe (35) passes through the insulation sleeve (37) in a hermetically sealed gas dome structure (1). The method of claim 7, wherein
The insulating sleeve 37 comprises two coaxial cylindrical walls which are closely connected together and spaced apart from each other by an annular gap,
The insulating sleeve (37) comprises a sealable connector (38) which is open on the inside of the annular gap and is suitable for connecting to a vacuum pump for placing the annular gap under vacuum. The method according to any one of claims 6 to 8,
The vapor collecting pipe 35 has a bend arranged inside the inner drum 23 and comprises an interior 36 oriented parallel to the inner drum 23 towards the inner space of the tank. The method of claim 9,
A gas further comprising a support device 39 for supporting the lower portion 36 of the vapor collection pipe 35 and arranged to distribute the force exerted on the lower portion 36 around the inner circumference of the inner drum 23. Dome structure (1). The method of claim 10,
The supporting device 39 is attached to the inner drum 23 and protrudes radially toward the inner side of the inner drum 23. The first annular plate 40 is attached to the lower part of the vapor collecting pipe 35 to attach the vapor collecting pipe. A second annular plate 41 projecting radially outwardly of the lower part 36 of the 35 and around the lower part 36 of the vapor collecting pipe 35 so as to be distributed at regular intervals. A gas dome structure (1) comprising a plurality of support arms (42) each comprising a first end attached to 40 and a second end attached to a second annular plate (41). The method according to any one of claims 9 to 11,
The bottom 36 of the vapor collection pipe 35 is a gas dome structure 1 with a filter 44. The method according to any one of claims 4 to 9,
The vapor collecting pipe 38 is connected to a three-way connection 47 arranged outside the outer drum 23. The method according to any one of claims 1 to 13,
Gas dome structure (1), wherein the inner drum (23) and the outer drum (20) comprise bellows regions (31, 32), respectively. The method according to any one of claims 1 to 14,
The intermediate insulation gap 24 is a gas dome structure 1 filled with a gaseous state and / or insulation lining 34 disposed under vacuum. The method according to any one of claims 1 to 15,
The intermediate insulation gap 24 has a gas dome structure 1 with a bottom that is tightly occluded by an annular flange 29. The method according to any one of claims 1 to 16,
An additional drum 51 and an additional drum 51 and an external drum having radially extending outside the outer drum 20 and having an upper end welded to the first collar 21 and a lower end welded to the second collar 22. 20. A gas dome structure (1), further comprising an insulating lining (53) arranged between. The method according to any one of claims 1 to 17,
The intermediate insulating gap 24 arranged between the inner drum 23 and the outer drum 20 is divided into a primary compartment 24a and a secondary compartment 24b which are sealed to each other. The method of claim 18,
The primary compartment is provided with an outer drum and has one or more ports intended to allow the primary compartment to communicate with the primary insulating barrier. A fluid storage device comprising a closed and insulated tank arranged at a double hull and a double hull defined by an inner hull (4) and an outer hull (5).
A thermal barrier 6 seated at the inner hull 5,
A sealing membrane 9 intended to be in contact with the fluid contained in the tank and
An outer hull 4, an inner hull 5, a thermal barrier 6 and a sealing to provide a path for the steam to flow between the inner space of the tank and at least one steam header 3 arranged outside the tank 20. A gas dome structure 1 according to any one of claims 1 to 19 passing through the membrane 9,
The first collar 21 of the gas dome structure 1 is welded to the outer hull 4 around the opening 18 provided in the outer hull 4,
The second collar 22 of the gas dome structure 1 is welded to the inner hull 5 around the opening 19 provided in the inner hull 5,
Fluid storage device in which the inner drum (23) is intimately connected to the sealing membrane (9). The method of claim 20,
The opening 18 provided in the inner hull 4 has a smaller diameter than the opening 19 provided in the outer hull 5,
The second collar (22) has a diameter smaller than the opening (19) provided in the outer hull (5) and having a diameter larger than the opening (18) provided in the inner hump (4). The method of claim 20 or 21,
The thermal barrier is a secondary thermal barrier 6,
The sealing membrane is the primary sealing membrane 9,
The tank further comprises a secondary sealing membrane 7 seated on the secondary insulating barrier 6 and a primary insulating barrier 9 arranged between the secondary sealing membrane 7 and the primary sealing membrane 9; ,
The outer drum comprises a third collar (30) projecting radially outwardly of the outer drum (20) and intimately connected to the secondary sealing membrane (7). 23. A fluid storage device according to any one of claims 20 to 22, configured in the form of a ship. 24. A method for loading or unloading a fluid storage device according to any one of claims 20 to 23.
Conveying the fluid through an insulated pipe (73, 79, 76, 81) from a marine or onshore storage facility (77) to a tank of a storage device and vice versa. As a delivery system for a fluid, the system is
A fluid storage device according to any one of claims 20 to 23,
Insulated pipelines 73, 79, 76, 81 arranged to connect tanks 71 to marine or onshore storage facilities 77;
A pump comprising a pump for sending fluid from an offshore or onshore storage facility to a tank or vice versa, via an insulated pipeline.

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