Liquefied gas storage facility with dome structure supporting spray boom

Abstract

The present invention relates to a liquefied gas storage facility having a dome structure (25), wherein the dome structure (25) comprises an outer cylinder (26), an inner cylinder (29) having a lower end welded to a sealed membrane (17), a support duct (33) passing through the inner cylinder (29), and a crown ring (38) supporting a spray boom (34) and fixed to the bottom of the support duct (33), wherein the spray boom (34) comprises a plurality of spray nozzles (45), and the crown ring (38) has a diameter (d1) larger than the diameter (d2) of the inner cylinder (29).

Description

Technical Field

[0001] The present invention relates to the field of tanks with a hermetic insulation structure for storing and / or transporting liquefied gas. For example, it relates to a tank for transporting liquefied petroleum gas (also referred to as LPG) having a temperature range of -50°C to 0°C, or a tank for transporting liquefied natural gas (LNG) at approximately -162°C under atmospheric pressure.

[0002] These tanks can be installed either on land or on floating structures. In the case of floating structures, the tank can be used for transporting liquefied gas or for storing liquefied gas supplied as fuel for propelling the floating structure.

[0003] More specifically, the present invention relates to a tank having a dome structure penetrating an aperture formed in the ceiling wall of the tank, and a spray boom for spraying liquefied gas into the tank is provided in the dome structure.

Background Art

[0004] Korean Patent Publication No. 2014-0088975 discloses a dome structure for a tank with a hermetic insulation structure for storing liquefied gas. The dome structure includes: - an inner cylinder that penetrates an aperture formed in the support structure of the ceiling wall, penetrates the ceiling wall of the tank, and is hermetically welded to the primary sealing membrane of the ceiling wall; - an outer cylinder disposed around the inner cylinder and welded to the support structure around the aperture through which the inner cylinder passes; - a support duct for the purpose of venting gas and passing through the inner cylinder; - a spray boom for spraying liquefied gas into the support duct and attached to a crown ring fixed to the lower end of the support duct; and the like.

[0005] However, such dome structures are not entirely satisfactory. In particular, the diameter of the inner cylinder is very important. That is, when the support duct is lowered and inserted into the spray boom during the assembly of the dome structure, the diameter of the inner cylinder must be larger than the diameter of the spray boom and the crown ring that supports it in order to allow the spray boom and the crown ring that supports it to pass through the inner cylinder. On the other hand, since the primary sealing membrane is welded to the inner cylinder, it is desirable that the diameter of the inner cylinder be limited in order to suppress the decrease in the elasticity of the primary sealing membrane in the welding zone to the inner cylinder.

[0006] Furthermore, the inside of the inner cylinder may be subjected to dynamic pressure caused by the movement of the cargo within the tank, i.e., the so-called "sloshing" effect. This cargo movement can also cause liquefied gas to be undesirably present within the dome structure and in the gas extraction ducts opening into the dome structure. However, such gas extraction ducts may contain compressors that are susceptible to damage from the presence of liquefied gas. [Overview of the project]

[0007] One of the fundamental ideas behind this invention is to design a liquefied gas storage facility equipped with the dome structure described above, which makes it possible to suppress the aforementioned drawbacks, particularly the decrease in elasticity of the sealing membrane caused by welding the sealing membrane to the inner cylinder of the dome structure.

[0008] According to one embodiment, the present invention is A support structure comprising an upper support wall that defines the internal space and has an aperture, A sealed insulated tank having a ceiling wall having at least one insulating barrier fixed to the upper support wall and a sealed membrane intended to come into contact with liquefied gas, A liquefied gas storage facility equipped with, The aforementioned facility has a dome structure, The aforementioned dome structure is - An outer cylinder extending outward from the support structure and having a lower end welded around the aperture of the support structure, - An inner cylinder that passes through the aperture of the support structure and the ceiling wall and extends into the interior of the outer cylinder, having a lower end welded to the sealing membrane, - A support duct that passes through the inner cylinder and has a bottom portion that extends downward from the lower end of the inner cylinder, - A supply duct intended to be supplied with liquefied gas and fixed to the support duct, -A crown ring that supports a spray boom and is fixed to the bottom of the support duct, wherein the spray boom has a plurality of spray nozzles and is connected to the supply duct, and the crown ring has a diameter larger than the diameter of the inner cylinder, This relates to a liquefied gas storage facility equipped with [a specific feature].

[0009] According to one embodiment, the present invention further relates to a method for assembling a dome structure for a liquefied gas storage facility, - A step of providing a support structure that defines the internal space, comprising providing a support structure that includes an upper support wall having an aperture that receives the ceiling wall of a sealed insulated tank, - Steps of providing a gas dome structure, Equipped with, The aforementioned gas dome structure is - An outer cylinder extending outward from the support structure and having a lower end welded around the aperture of the support structure, - An inner cylinder that passes through the aperture of the support structure and extends into the interior of the outer cylinder, - A support duct that passes through the inner cylinder and has a bottom that extends downward from the lower end of the inner cylinder, - A supply duct intended to be supplied with liquefied gas and fixed to the support duct, Equipped with, The aforementioned assembly method further includes: - A step of providing a crown ring that supports a spray boom and has a plurality of spray nozzles, the crown ring having a diameter larger than the diameter of the inner cylinder, - A step of moving the crown ring out of the internal space and displacing it until the crown ring contacts the support duct, - The step of fixing the crown ring to the support duct, - The step of tightly connecting the upstream end of the spray boom to the downstream end of the supply duct, The present invention provides a method for assembly that includes the necessary components.

[0010] Therefore, the above equipment and method are particularly advantageous in that the diameter of the inner cylinder can be reduced relative to the predetermined installation diameter of the spray boom, and as a result, the reduction in the elasticity of the sealing membrane can be particularly suppressed. Furthermore, the crown ring makes it possible to protect the inside of the inner cylinder from the movement of liquefied gas in the tank. More specifically, the crown ring can particularly prevent the presence of liquefied gas in the gas extraction duct, including the compressor.

[0011] According to the embodiment, the above-mentioned equipment and method may have one or more of the following features.

[0012] According to one embodiment, the support duct is provided with a fixing collar that extends radially around the support duct, and the crown ring is provided with an annular bottom fixed to the bottom surface of the fixing collar. With this configuration, the crown ring can be easily fixed to the support duct from the internal space side.

[0013] According to one embodiment, the annular bottom of the crown ring has an opening, the opening is positioned around the support duct, and the edge of the opening is welded to the fixing collar. This makes it possible to fix the crown ring to the support duct from the internal space side.

[0014] According to one embodiment, the fixed collar and the annular bottom are provided with an orifice that allows the fixing member to pass through the fixed collar and the annular bottom.

[0015] According to one embodiment, the fixed collar and the annular bottom each have an aperture, and the apertures are arranged to face each other and the supply duct penetrates therethrough.

[0016] According to one embodiment, in the welding zone located below the annular bottom, the spray boom is connected to the supply duct.

[0017] According to one embodiment, the bottom of the support duct includes a bottom wall that closes the lower end of the support duct and a window formed in the cylindrical wall of the bottom of the support duct, and the welding zone is arranged at a position facing any one of the windows. This facilitates the welding operation, and particularly improves the operability of the welding torch.

[0018] According to one embodiment, the support duct includes a fixed collar that extends radially around the support duct, the crown ring includes an annular bottom, and in order to fix the crown ring to the support duct, the annular bottom of the crown ring is welded to the bottom surface of the fixed collar.

[0019] According to one embodiment, before welding the annular bottom of the crown ring to the bottom surface of the fixed collar, the fixed collar and the annular bottom are fixed to each other by a temporary fixing member.

[0020] According to one embodiment, the fixing member is a temporary fixing member.

[0021] According to one embodiment, the temporary fixing member is removed after the operation of welding the annular bottom of the crown ring to the bottom surface of the fixed collar. Thereby, it is possible to prevent the fixing member from falling off and damaging the bottom wall of the tank, particularly its primary sealing membrane.

[0022] According to one embodiment, the annular bottom of the crown ring has an opening arranged around the support duct, and the edge of the opening is welded to the fixed collar.

[0023] According to one embodiment, The bottom of the support duct is A bottom wall that closes the lower end of the support duct, A window formed in the cylindrical wall at the bottom of the support duct, Equipped with, In a welding zone positioned opposite any one of the aforementioned windows, the upstream end of the spray boom is welded to the downstream end of the supply duct.

[0024] According to one embodiment, the dome structure includes a protective plate fixed to the lower end of the support duct, the protective plate covering the crown ring and having a plurality of holes.

[0025] According to one embodiment, the inner cylinder is fixed to the outer cylinder.

[0026] According to one embodiment, the inner cylinder is fixed to the outer cylinder by an upper anchoring device and a lower anchoring device.

[0027] According to one embodiment, the inner cylinder is fixed to the outer cylinder by a lower anchoring device, the lower anchoring device is positioned at a distance h from the lower end of the inner cylinder, and the distance h is determined such that the contraction Δh of the distance h during tank cooling satisfies 90% ≤ Δh / Δl ≤ 110%. Here, Δl is the vertical displacement of the sealing membrane 17 due to the contraction of the primary adiabatic barrier 15 and the secondary adiabatic barrier 12 during tank cooling.

[0028] Such facilities can constitute part of onshore storage facilities (e.g., LNG storage facilities), and can also be installed on floating, coastal, or deep-sea structures, including, in particular, methane tankers, floating storage and regasification units (FSRUs), and floating production storage and offloading (FPSOs). Such tanks can also be used as fuel tanks on all types of vessels.

[0029] According to one embodiment, a ship transporting liquefied gas is equipped with the aforementioned type of liquefied gas storage facility.

[0030] According to one embodiment, the present invention further states The above ship and, The tanks of the liquefied gas storage facility of the aforementioned ship are connected to a floating or onshore storage facility via an insulated pipeline, A pump for moving liquefied gas through the insulated pipeline from the floating or onshore storage facility to the tank of the ship's liquefied gas storage facility, or from the tank to the floating or onshore storage facility, We provide a liquefied gas transfer system equipped with [the specified features].

[0031] According to one embodiment, the present invention further relates to a method for loading or unloading the above-mentioned vessel, The present invention provides a method for moving liquefied gas from a floating or onshore storage facility to a tank in a liquefied gas storage facility installed on a ship, or from the tank to the floating or onshore storage facility, via an insulated pipeline.

[0032] The present invention will be better understood from the description of several specific embodiments shown below in a purely illustrative and non-limiting manner with reference to the accompanying drawings, and other purposes, details, features, and advantages will also be more clearly grasped. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 is a schematic perspective view of a support structure for a sealed, insulated liquefied gas storage tank. (The dome structure is not shown.) [Figure 2] Figure 2 is a schematic diagram showing the multi-layered structure of the tank wall. [Figure 3] Figure 3 is a cross-sectional view of the dome structure according to the embodiment, and the dome structure penetrates the ceiling wall of the sealed insulated tank. [Figure 4] Figure 4 is another cross-sectional view of the dome structure shown in Figure 3. [Figure 5] Figure 5 is a cross-sectional perspective view of the dome structure shown in Figure 2, where the dome structure penetrates the ceiling wall of the sealed, insulated tank. [Figure 6] Figure 6 is a detailed view of the dome structure shown in Figures 2 and 3, and in particular shows the spray boom and the crown ring that secures the spray boom to the support duct. [Figure 7] Figure 7 is a bottom view of the support crown ring and spray boom. [Figure 8] Figure 8 is a perspective view of the support crown ring and the spray boom from below. [Figure 9] Figure 9 is a bottom perspective view showing another embodiment in which a protective plate is positioned below the support crown ring. [Figure 10] Figure 10 is a schematic cross-sectional view of a ship equipped with liquefied natural gas storage tanks and a terminal for loading / unloading those tanks. [Modes for carrying out the invention]

[0034] With respect to Figure 1, a support structure 1 is described, to which a sealed, insulated liquefied gas storage tank is intended to be fixed. The support structure 1 is formed, for example, by a ship's double hull. The double hull consists of an outer hull 19 and an inner hull 18 located inside it. The support structure 1 has a generally polyhedral shape. The support structure 1 has two support walls, front and rear (here having an octagonal shape), and only the rear support wall 2 is shown in Figure 1. The front and rear walls 2 are, for example, bulkheads of a ship and extend laterally with respect to the longitudinal direction of the ship. Furthermore, the support structure 1 includes an upper support wall 3, a lower support wall 4, and side support walls 5, 6, 7, 8, 9, and 10. The sealed, insulated liquefied gas storage tank has each tank wall fixed to one of the support walls 2, 3, 5, 6, 7, 8, 9, and 10 of the support structure 1, thereby forming an internal space for containing liquefied gas.

[0035] As shown in Figure 2, each wall of the tank is sequentially laid out from the outside to the inside, along the thickness direction of the wall. - A secondary thermal insulation barrier 12 including a thermal insulation member 13 fixed to the support structure 1, - A secondary sealing membrane 14 fixed to the insulating member 13 of the secondary insulating barrier 12, -A primary thermal insulation barrier 15 including a thermal insulation member 16 that is fixed to the thermal insulation member 13 or support structure 1 of the secondary thermal insulation barrier 12 and is in contact with the secondary sealing membrane 14, -A primary sealing membrane 17 is fixed to the insulating member 16 of the primary insulating barrier 15 and is intended to come into contact with the liquefied gas inside the tank, It is equipped with.

[0036] The liquefied gases stored in the tanks may include, in particular, ethane, liquefied natural gas (LNG), which is a gas mixture mainly containing methane and one or more other hydrocarbons, or liquefied petroleum gas (LPG), which is a hydrocarbon mixture derived from petroleum refining and mainly contains propane and butane.

[0037] In the embodiments shown in Figures 3 and 4, the thermal insulation member 13 of the secondary thermal insulation barrier 12 is composed of a secondary thermal insulation panel 20, which comprises a thermal insulation polymer foam layer 21 made of, for example, polyurethane, and the thermal insulation polymer foam layer 21 is sandwiched between a cover plate 22 and a bottom plate 23, the cover plate 22 and bottom plate 23 being rigid and made of, for example, plywood.

[0038] The secondary sealing membrane 14 is formed of a continuous sheet of strakes having raised edges. Each strake has a central flat portion resting on the cover plate of the secondary insulation panel 20 and two raised edges protruding into the tank. The strakes are attached to welded supports fixed to grooves formed in the cover plate of the secondary insulation panel 20 by welding their raised edges. The strakes are manufactured from, for example, Invar®, an alloy of iron and nickel, and have a coefficient of thermal expansion of typically 1.2 × 10⁻⁶. -6 K -1 ~2.0×10 -6 K -1 It is within this range. Furthermore, an alloy of iron and manganese can be used, and its coefficient of thermal expansion is approximately 7 × 10⁻⁶. -6 K -1 ~10×10 -6 K -1 That is the case.

[0039] The insulation member 16 of the primary insulation barrier 15 is composed of a primary insulation panel 24, which comprises an insulating polymer foam layer made of, for example, polyurethane, and the insulating polymer foam layer is sandwiched between a cover plate and a bottom plate, the cover plate and bottom plate being rigid and made of, for example, plywood.

[0040] The primary sealing membrane 17 is constructed by combining multiple corrugated metal plates. The multiple corrugated metal plates are joined together by welding their edges. The corrugations protrude into the tank. The corrugated metal plates are attached to anchoring bands fixed to countersunk holes formed in the cover plate of the primary insulation panel 24. The material of the corrugated metal plates is, for example, stainless steel or aluminum.

[0041] Alternatively, the tank walls may be manufactured in accordance with the technology described in International Publication No. 2014 / 057221, French Patent Application Publication No. 2691520, and French Patent Application Publication No. 2877638, which pertain to the Mark V, Mark III (registered trademark), and NO96 (registered trademark) products developed by the applicant.

[0042] With respect to Figures 3 and 4, a dome structure 25 according to one embodiment is described below. The dome structure 25 comprises an outer cylinder 26, which is cylindrical and extends in the thickness direction of the tank's ceiling wall. The outer cylinder 26 passes through an aperture formed in the outer hull 19. The lower end of the outer cylinder 26 is tightly welded to the inner hull 18, which has an aperture 27 formed in it. The upper end of the outer cylinder 26 is sealed by a removable cover 28.

[0043] The dome structure 25 also includes an inner cylinder 29 positioned inside the outer cylinder 26. The inner cylinder 29 is positioned concentrically with the outer cylinder 26 and penetrates an aperture 27 formed in the inner hull 18. Furthermore, the inner cylinder 29 also penetrates the upper wall of the tank. The lower end of the inner cylinder 29 is tightly welded to the primary sealing membrane 17, thereby ensuring the airtightness of the primary thermal barrier 15 to the internal space of the tank. The inner cylinder 29 is provided with a compensation device 30 consisting of a row of bellows, which gives the inner cylinder 29 longitudinal flexibility, allowing it to contract and expand. The outer cylinder 26 and the inner cylinder 29 are fixed to each other by an upper anchoring device 31 and a lower anchoring device 32, which will be described later. Both ends of the inner cylinder 29 are open.

[0044] The dome structure 25 also includes a support duct 33 that is concentric with and penetrates the inner cylinder 29. This support duct 33 has two main functions: to support a spray boom 34 for spraying liquefied gas into the tank, and to guide the vapor phase of the gas from the tank's internal space to a collection zone 35 located at the upper end of the dome structure 25.

[0045] The support duct 33 is equipped with a support collar 36 welded to its upper end and projecting radially outward. The support collar 36 is welded to the outer cylinder 26 and abuts against an annular flange 37 that projects radially inward. The support collar 36 and the annular flange 37 are firmly welded to each other.

[0046] The dome structure 25 also includes a crown ring 38 that supports the spray boom 34, which is fixed to the lower end of the support duct 33. In the shown embodiment, the crown ring 38 includes an annular base 39, which extends around the support duct 33 along a plane perpendicular to the thickness direction of the ceiling wall. The crown ring 38 further includes a cylindrical rim 40 that projects downward from the radial outer edge of the annular base 39. In the shown embodiment, the annular base 39 and the cylindrical rim 40 are fixed to each other by a plurality of cleats, which are welded to the annular base 39 and the cylindrical rim 40.

[0047] The annular base 39 is welded to the support duct 33 and to a fixing collar 41 that extends radially around it. The fixing collar 41 is positioned at a certain distance from the lower end of the support duct 33, so that the bottom of the support duct 33 protrudes below the annular base 39 of the crown ring 38.

[0048] The bottom of the support duct 33 includes a bottom wall 42 that closes the lower end of the support duct 33 and a window 43 formed in the cylindrical wall of the bottom. There are at least two windows 43, and in the shown embodiment, there are four. The windows 43 are evenly distributed around the axis of the support duct 33. This structure prevents liquid-phase gas from entering the support duct 33.

[0049] The spray boom 34 comprises one or more rings 44 arranged around the crown ring 38, particularly around the cylindrical rim 40. Each ring 44 is equipped with multiple spray nozzles 45, which are evenly spaced around the central axis of the crown ring 38. Each ring 44 is secured to the crown ring 38 by appropriate means, such as a fixing clamp 46 or fixing clip shown in Figure 7. Furthermore, the cylindrical rim 40 is provided with grooves through which the bent portion of the spray boom 34 can pass, and each ring 44 can be connected to a supply duct 47.

[0050] Furthermore, as shown in Figures 6-8, for example, each ring 44 of the spray boom 34 is connected to a supply duct 47 for supplying liquefied gas to the spray boom 34. As shown in Figure 3, for example, the supply duct 47 extends from one end to the other, passing through an inner cylinder 29 and an outer cylinder 26. The supply duct 47 is connected to a pump (not shown), which is configured to deliver liquefied gas to, for example, a tank or dedicated storage vessel. As can be seen in Figure 3, each supply duct 47 is provided with a spiral zone 48 that wraps around the support duct 33, thereby allowing the supply duct 47 to contract and expand due to heat. Furthermore, the supply duct 47 is fixed to the support duct 33 by anchoring devices 49, which are particularly shown in Figure 3. The anchoring devices 49 are evenly distributed along the support duct 33. Preferably, the anchoring devices 49 allow the supply duct 47 to slide and fix, that is, they are structured to move relative to the support duct 33 so that the supply duct 47 can contract and expand.

[0051] As shown in Figure 3, the diameter d2 of the inner cylinder 29 is smaller than the diameter d1 of the crown ring 38. Similarly, the diameter d3 of the aperture 27 formed in the inner hull 18 is preferably smaller than the diameter d2 of the crown ring 38. Such an arrangement offers several advantages compared to the prior art arrangement in which the diameter d2 of the inner cylinder 29 is larger than the diameter of the crown ring 38. On the one hand, if the installation diameter of the spray boom 34 is fixed, the smaller diameter d2 of the inner cylinder 29 limits the interruption of the corrugated portion of the primary sealing membrane 17, thereby reducing the loss of elasticity of the primary sealing membrane 17 caused by the interruption. On the other hand, the crown ring 38 allows for protection of the inside of the inner cylinder 29 from the movement of liquefied gas inside the tank. Specifically, the crown ring 38 can prevent the presence of liquefied gas in the gas extraction duct, including the compressor. As will be described later, in order to enable the installation of such a dome structure 25, the assembly including the crown ring 38 and the spray boom 34 is fixed to the support duct 33 and installed from the internal space of the tank after the support duct 33 has been lowered through the inner cylinder 29.

[0052] Returning to Figure 3, we can see the upper anchoring device 31 and lower anchoring device 32 that fix the inner cylinder 29 to the outer cylinder 26. The upper anchoring device 31 includes a support collar 50 welded to the inner cylinder 29 and projecting radially around it, and an annular flange 51 welded to the outer cylinder 26 and projecting radially inward. The support collar 50 is in contact with the annular flange 51. The support collar 50 and the annular flange 51 are firmly welded to each other. As a result, a secondary sealed space 52 is formed between the outer cylinder 26 and the inner cylinder 29 below the support collar 50 and the annular flange 51. In a preferred embodiment, a heat insulating layer 65 is uniformly distributed over the entire outer circumference of the inner cylinder 29, as shown by the dotted lines in Figures 3 and 4.

[0053] Furthermore, the lower anchoring device 32 includes a tapered support member 53 that widens downwards, and this member is welded around the inner cylinder 29. It also includes a support ring welded to the radial outer edge of the tapered support member 53, and this support ring is provided with a support collar 54 that projects radially outward. The lower anchoring device 32 further includes an annular flange 55 welded to the outer cylinder 26 and projecting radially inward. The support collar 54 abuts the annular flange 55 either directly or via a filling block 56 interposed between the support collar 54 and the annular flange 55, as in the expressed embodiment. The filling block 56 is, for example, made of wood and is bonded to the support collar 54 and the annular flange 55 using, for example, resin. Preferably, the thickness of the filling block 56 is determined to accommodate manufacturing and / or positioning tolerances of the inner cylinder 29 and outer cylinder 26 in the thickness direction of the tank ceiling wall.

[0054] The inner cylinder 29 is fixed to the outer cylinder 26 at a distance h from the lower end. In a preferred embodiment, this distance h is determined such that the contraction Δh when the tank is cooled is approximately equal to the vertical displacement Δl due to the contraction of the primary sealing membrane 17. The displacement of the primary sealing membrane 17 is caused by the contraction of the primary adiabatic barrier 15 and the secondary adiabatic barrier 12. This prevents, or at least limits, the step effect that occurs between the primary sealing membrane 17 and the lower end of the inner cylinder 29.

[0055] The dome structure 25 further includes a sheath 57, shown in Figures 3 and 4, which is concentric with the outer cylinder 26 and located radially between the outer cylinder 26 and the inner cylinder 29. The sheath 57 also passes through an aperture 27 formed in the inner hull 18. A sealed primary space 58 is formed between the sheath 57 and the inner cylinder 29, communicating with the primary thermal barrier 15.

[0056] As shown in Figure 4, the dome structure 25 includes an exhaust duct 59 that opens into a sealed primary space 58. The exhaust duct 59 is connected to a valve (not shown) which is normally closed and opens when the pressure in the primary adiabatic barrier 15 exceeds a predetermined threshold pressure. Thus, the exhaust duct 59 is intended to protect the primary sealing membrane 17 from any overpressure that may occur in the primary adiabatic barrier 15. In a preferred embodiment, the exhaust duct 59 includes a helical zone that wraps around the inner cylinder 29, thereby allowing thermal contraction and expansion of the exhaust duct 59.

[0057] The dome structure 25 is further equipped with an inert gas supply duct 60 that also opens into the sealed primary space 58. The inert gas supply duct 60 is connected to a storage tank of an inert gas such as nitrogen, which is connected by a pump, thereby allowing the inert gas to be circulated within the primary insulated barrier 15.

[0058] Furthermore, as shown in Figure 4, the sheath 57 is not welded to the inner hull 18 of the double hull, thereby forming an annular passage between the sheath 57 and the inner hull 18. The exhaust duct 61 and inert gas supply duct 62 shown in Figure 4 tightly penetrate the outer cylinder 26 and open into the secondary sealed space 52. The exhaust duct 61 is connected to a valve that is closed by default and opens when the pressure inside the secondary adiabatic barrier 12 exceeds a predetermined threshold. This structure protects the secondary sealed membrane 14 from any overpressure that may occur inside the secondary adiabatic barrier 12. The inert gas supply duct 62 is connected by a pump to an inert gas storage tank such as nitrogen, thereby circulating the inert gas inside the secondary adiabatic barrier 12.

[0059] Furthermore, the dome structure 25 is equipped with at least one steam collection duct 63, 64, which closely penetrates the wall of the outer cylinder 26 and opens into a collection zone 35 located at the upper end of the dome structure 25. This allows the steam collection duct 63, 64 to guide steam between the collection zone 35 and a steam collector (not shown) located outside the dome structure 25.

[0060] Next, the method for installing the dome structure 25 described above will be explained. First, the first part of the dome structure 25, without the crown ring 38 and spray boom 34, is assembled and fixed to the support structure 1. For this purpose, the outer cylinder 26 is tightly welded around the aperture 27 of the inner hull 18. Next, the inner cylinder 29 is lowered from the upper end of the outer cylinder 26. To enable this operation, the inner diameter of the annular flange 37 is set to be larger than the outer diameter of the support collars 50 and 54, and the inner diameter of the annular flange 51 is set to be larger than the outer diameter of the support collar 54. Furthermore, the support duct 33 is also lowered through the outer cylinder 26 and inner cylinder 29 and positioned until the support collar 36 welded to the support duct 33 contacts the annular flange 37.

[0061] Next, the crown ring 38 and the spray boom 34 fixed to the crown ring 38 are brought closer to the support duct 33 through the space inside the tank and fixed to it. For this purpose, as shown in Figure 8, the fixing collar 41 and the crown ring 38 are provided with orifices 66, and by facing these orifices 66 toward each other, the temporary fixing member 67 can be passed through. For example, the temporary fixing member 67 is made up of a combination of screws and nuts. Furthermore, the crown ring 38, in particular the annular bottom 39, is provided with openings 68, which are evenly distributed around the support duct 33, allowing the crown ring 38 to be welded to the fixing collar 41 from below. Thus, the edges of the openings 68 are welded to the fixing collar 41. After welding the crown ring 38 to the fixing collar 41, the temporary fixing member 67 can be removed, thereby preventing it from falling into the tank and damaging the primary sealing membrane 17.

[0062] The spray boom 34 is also connected to one or more supply ducts 47. As shown in Figure 7, apertures 69 are provided in the annular bottom 39 of the crown ring 38 and the fixed collar 41, respectively, allowing the supply ducts 47 to pass through the fixed collar 41 and the annular bottom 39 of the crown ring 38. To ensure airtightness of the connection, the spray boom 34 is welded to the supply ducts 47 in a welding zone 82, one of which is shown as a dotted line in Figure 8. To facilitate welding operations, particularly the operation of the welding torch, the welding zone 82 is positioned to face radially to one of the windows 43 formed at the bottom of the support duct 33, if possible.

[0063] Figure 9 shows a dome structure 25 in another embodiment. This embodiment differs from those described in Figures 3-8 in that it further includes a protective plate 83 fixed to the lower end of the support duct 33. This protective plate 83 is shaped to cover the crown ring 38 and has a number of holes 84. Through these holes 84, vapor phase gas can enter the support duct via the window 43. Such a protective plate 83 protects the crown ring 38 from the movement of liquid liquefied gas in the tank and further prevents liquid liquefied gas from reaching the inside of the support duct 33 and the gas extraction line including the compressor.

[0064] As shown in Figure 10, the cross-sectional view of the methane tanker 70 shows a roughly rectangular prism-shaped sealed insulated tank 71 mounted inside the ship's double hull 72. The walls of the tank 71 include a primary sealing membrane in contact with the LNG held inside the tank, a secondary sealing membrane positioned between the primary sealing membrane and the ship's double hull 72, and two insulating barriers positioned between the primary sealing membrane and the secondary sealing membrane, and between the secondary sealing membrane and the double hull 72, respectively.

[0065] As is well known, loading / unloading pipelines 73 installed on the top deck of a ship can be connected to offshore or port terminals via appropriate connectors, and can transport LNG to or from tanks 71.

[0066] Figure 10 shows an example of a marine terminal equipped with a loading / unloading station 75, an underwater duct 76, and land-based facilities 77. The loading / unloading station 75 is a fixed marine facility comprising a movable arm 74 and a tower 78 supporting the movable arm 74. A bundle of insulated flexible pipes 79 is attached to the movable arm 74 and can be connected to a loading / unloading pipeline 73. The movable arm 74 is directionally adjustable and can adapt to the shape of all methane tankers. A link duct (not shown) is provided inside the tower 78. The loading / unloading station 75 enables loading and unloading of methane tankers 70 from the land-based facilities 77. The land-based facilities 77 include a liquefied gas storage tank 80 and a link duct 81, which are connected to the loading / unloading station 75 via the underwater duct 76. The underwater duct 76 makes it possible to transfer liquefied gas over long distances (e.g., 5 km) between the loading / unloading station 75 and the onshore facilities 77, and allows the methane tanker 70 to be kept far enough away from the coast during loading and unloading operations.

[0067] Pumps mounted on the ship 70 and / or pumps provided at the shore facility 77 and / or pumps provided at the loading / unloading station 75 are used to generate the pressure necessary for the transfer of the liquefied gas.

[0068] Although the present invention has been described in relation to several specific embodiments, it is not limited thereto, and it is clear that all technical equivalents of the described means and combinations thereof are also included in the present invention, insofar as they fall within the scope of the present invention as defined by the claims.

[0069] Even when using verbs such as "comprise" or "include" or their conjugations to describe the elements or processes described in the claims, this does not preclude the existence of elements or processes other than those described in the claims.

[0070] Reference numerals in parentheses in a claim should not be construed as limitations of the claim.

Claims

1. A support structure (1) comprising an upper support wall (3) that defines the internal space and has an aperture (27), A sealed insulated tank having a ceiling wall having at least one insulating barrier (12, 15) fixed to the upper support wall (3) and a sealed membrane (17) intended to come into contact with liquefied gas, A liquefied gas storage facility equipped with, The liquefied gas storage facility is equipped with a dome structure (25), The aforementioned dome structure (25) is - An outer cylinder (26) extending to the outside of the support structure (1) and having a lower end welded around the aperture (27) of the support structure (1), - An inner cylinder (29) that passes through the support structure (1) and the aperture (27) of the ceiling wall and extends into the interior of the outer cylinder (26), the inner cylinder (29) having a lower end welded to the sealing membrane (17), - A support duct (33) that passes through the inner cylinder (29) and has a bottom that extends downward from the lower end of the inner cylinder (29), - A supply duct (47) is intended to be supplied with liquefied gas and is fixed to the support duct (33), - A crown ring (38) that supports the spray boom (34) and is fixed to the bottom of the support duct (33), wherein the spray boom (34) has a plurality of spray nozzles (45) and is connected to the supply duct (47), and the crown ring (38) has a diameter (d1) that is larger than the diameter (d2) of the inner cylinder (29), A liquefied gas storage facility equipped with [the following features].

2. The support duct (33) is provided with a fixing collar (41) that extends radially around the support duct (33), The crown ring (38) has an annular bottom portion (39) fixed to the bottom surface of the fixed collar (41). The liquefied gas storage facility according to claim 1.

3. The annular bottom portion (39) of the crown ring (38) is provided with an opening (68). The opening (68) is positioned around the support duct (33), and the edge of the opening (68) is welded to the fixing collar (41). The liquefied gas storage facility according to claim 2.

4. The fixing collar (41) and the annular bottom portion (39) are provided with an orifice that allows the fixing member (67) to pass through the fixing collar (41) and the annular bottom portion (39). The liquefied gas storage facility according to claim 2 or 3.

5. The fixed collar (41) and the annular bottom portion (39) each have an aperture (69), The apertures (69) are arranged facing each other, and the supply duct (47) passes through them. A liquefied gas storage facility according to any one of claims 2 to 4.

6. In the welding zone (82) located below the annular bottom portion (39), the spray boom (34) is connected to the supply duct (47). A liquefied gas storage facility according to any one of claims 1 to 5.

7. The bottom of the support duct (33) is The bottom wall (42) closes the lower end of the support duct (33), The window (43) formed in the cylindrical wall at the bottom of the support duct (33), Equipped with, The welding zone (82) is positioned opposite one of the windows (43). The liquefied gas storage facility according to claim 6.

8. A protective plate (83) is fixed to the lower end of the support duct (33), and the protective plate (83) covers the crown ring (38) and has a plurality of holes (84). A liquefied gas storage facility according to any one of claims 1 to 7.

9. A ship (70) for transporting liquefied gas, A liquefied gas storage facility according to any one of claims 1 to 8, Ship (70).

10. The ship (70) described in claim 9, Insulated pipelines (73, 79, 76, 81) are arranged to connect the tank (71) of the liquefied gas storage facility of the ship to a floating or onshore storage facility (77), A pump for moving liquefied gas through the insulated pipeline from the floating or onshore storage facility to the tank of the ship's liquefied gas storage facility, or from the tank to the floating or onshore storage facility, A liquefied gas transfer system equipped with [a specific feature].

11. A method for loading or unloading a ship (70) according to claim 9, A method for moving liquefied gas from a floating or onshore storage facility (77) to a tank (71) of a liquefied gas storage facility installed on a ship, or from the tank (71) to the floating or onshore storage facility (77), via insulated pipelines (73, 79, 76, 81).

12. A method for assembling the dome structure of a liquefied gas storage facility, - A step of providing a support structure (1) that defines the internal space, the support structure (1) comprising an upper support wall (3) having an aperture (27) that receives the ceiling wall of a sealed insulated tank, - Steps of providing a gas dome structure, Equipped with, The aforementioned gas dome structure (25) is - An outer cylinder (26) extending to the outside of the support structure (1) and having a lower end welded around the aperture (27) of the support structure (1), - The inner cylinder (29) passes through the aperture (27) of the support structure (1) and extends into the interior of the outer cylinder (26), - A support duct (33) that passes through the inner cylinder (29) and has a bottom that extends downward from the lower end of the inner cylinder (29), - A supply duct (47) is intended to be supplied with liquefied gas and is fixed to the support duct (33), Equipped with, The aforementioned assembly method further includes: - A step of providing a crown ring (38) that supports a spray boom (34) and has a plurality of spray nozzles (45), the crown ring (38) having a diameter (d1) larger than the diameter (d2) of the inner cylinder (29), - A step of moving the crown ring (38) out of the internal space and displacing it until the crown ring (38) comes into contact with the support duct (33), - The step of fixing the crown ring (38) to the support duct (33), - The step of tightly connecting the upstream end of the spray boom (34) to the downstream end of the supply duct (47), A method of assembly that includes the necessary components.

13. The support duct (33) is provided with a fixing collar (41) that extends radially around the support duct (33), The crown ring (38) is provided with an annular bottom portion (39), In order to fix the crown ring (38) to the support duct (33), the annular bottom portion (39) of the crown ring (38) is welded to the bottom surface of the fixing collar (41). The assembly method according to claim 12.

14. Before welding the annular bottom portion (39) of the crown ring (38) to the bottom surface of the fixing collar (41), the fixing collar (41) and the annular bottom portion (39) are fixed to each other by a temporary fixing member (67). The assembly method according to claim 13.

15. The annular bottom portion (39) of the crown ring (38) is provided with an opening (68) arranged around the support duct (33), The edge of the opening is welded to the fixing collar (41). The assembly method according to claim 12 or 13.

16. The bottom of the support duct (33) is The bottom wall (42) closes the lower end of the support duct (33), The window (43) formed in the cylindrical wall at the bottom of the support duct (33), Equipped with, In a welding zone (82) positioned opposite any one of the windows (43), the upstream end of the spray boom (34) is welded to the downstream end of the supply duct (47). The assembly method according to any one of claims 12 to 15.

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