Liquid dome of a liquefied gas storage tank

Abstract

Liquid dome of a liquefied gas storage tank The present invention relates to a sealed insulated tank comprising a liquefied gas storage facility (1) and a loading / unloading opening (10) having an upper cover wall (23), a lower cover wall (22), and an insulating structure (24) disposed between the lower cover wall (22) and the upper cover wall (23), wherein the conduit (30) of the liquid dome and the upper cover wall (23) are made of different iron-based alloys, and at least one fixed protrusion (50) protruding from the upper cover wall (23) is fixed so as to be sealed directly or indirectly to a primary sealing membrane (19).

Description

Technology Field

[0001] The present invention relates to the field of liquefied gas storage facilities comprising sealed and thermally insulating membrane tanks. In particular, the present invention relates to the field of sealed and insulating tanks for storing and / or transporting low-temperature liquefied gases, such as tanks for transporting liquefied petroleum gas (LPG) at temperatures ranging from -50°C to 0°C, or tanks for transporting liquefied natural gas (LNG) at approximately -162°C at atmospheric pressure. Such tanks may be installed on shores or on floating structures. On floating structures, the tanks may be used to contain liquefied gas used as fuel to transport the liquefied gas or to power the floating structure. Background Technology

[0002] Literature FR2991430 discloses a liquefied gas storage facility comprising a sealed insulated tank permanently installed in a load-bearing structure made of a double hull of a ship. Each wall of the tank comprises a secondary insulating barrier, a secondary sealing membrane, a primary insulating barrier, and a primary sealing membrane.

[0003] At the top of the tank, there is a protruding shaft-shaped portion called a liquid dome. In this area, the load-bearing structure is locally suspended to form a loading / unloading opening through which a fluid loading / unloading line passes. This loading / unloading opening, called the liquid dome, includes an insulating material or an insulating barrier and an element forming a primary sealing membrane.

[0004] In particular, while it is desirable to reduce the manufacturing cost of such liquid domes by using low-cost materials, this may result in properties that are less suitable for the very low temperatures to which the tank and the liquid dome are exposed. Additionally, the tank is installed in structures subjected to very high mechanical stress, such as ships that bend and twist depending on environmental conditions, and such mechanical stress is particularly detrimental to the structure of the liquid dome, which is relatively narrow and extends vertically, such as a shaft above an actual tank containing liquefied gas.

[0005] Various experiments and tests have shown that liquid dome conduits can be made of less expensive metal materials if a specific structure is provided that enables the liquid dome to withstand high stresses applied to it. The problem to be solved

[0006] The present application is primarily intended to propose a liquid dome that is less expensive but can withstand all stresses applied to the liquid dome, while ensuring perfect physical and thermal sealing for the extremely cold fluid contained in the tank. means of solving the problem

[0007] Accordingly, the present invention relates to a storage facility for liquefied gas comprising a load-bearing structure and a sealed insulating tank disposed inside the load-bearing structure, wherein

[0008] The above-described sealed insulated tank has a main structure formed by a plurality of interconnected tank walls that are fixed to the load-bearing structure, the main structure defines an internal storage space, the main structure includes at least one sealing membrane and at least one insulation barrier, and the insulation barrier is located between the sealing membrane and the load-bearing structure.

[0009] The above load-bearing structure generally has a flat upper load-bearing wall, and

[0010] The sealing membrane, the insulating barrier, and the upper load-bearing wall of the main structure are locally interrupted to define a conduit forming a load-bearing wall of a shaft extending along a vertical axis to an upper portion comprising a load-bearing opening through which a fluid load-bearing pipe passes, and the tank has a cover disposed at the load-bearing opening,

[0011] The above cover includes an upper cover wall, a lower cover wall, and an insulating structure disposed between the lower cover wall and the upper cover wall.

[0012] The present invention is characterized in that the conduit and the upper cover wall are made of different iron-based alloys, and at least a first fastening lug protruding from the upper cover wall is fixed to be sealed to the sealing membrane.

[0013] Many tests and analyses have shown that inexpensive carbon steel conduits can be used if a special arrangement is implemented to firmly secure the primary sealing membrane of the liquid dome, along with a certain degree of freedom to absorb thermal expansion.

[0014] Accordingly, the present invention provides significant savings in the construction of the liquid dome while ensuring or maintaining perfect sealing for liquefied gas and excellent mechanical strength of the liquid dome against all stresses typically received by this zone.

[0015] The term "conduit" refers to this element forming the outer wall of the liquid dome, more precisely, the wall of the shaft of the opening of the tank containing the liquefied gas. The term "shaft" refers to the general shape of the liquid dome extending vertically from the internal space of the tank itself.

[0016] Typically, the terms "external" and "internal" are used to determine the relative position of one element to another in relation to the inner and outer sides of a tank.

[0017] Other advantageous features of the present invention are briefly described below:

[0018] Advantageously, the sealing membrane comprises a primary membrane and then a secondary membrane extending from the interior of the internal storage space or conduit to the exterior of the tank, and at least one second fixed protrusion protruding from the upper cover wall is fixed to be sealed to the secondary membrane.

[0019] In this embodiment, the first fixed protrusion and the second fixed protrusion are independent of each other, preferably but not entirely.

[0020] Accordingly, the first fixed protrusion is not only sealedly connected to the primary sealing membrane of the liquid dome, but the second fixed protrusion is also connected to the insulating and sealing structure, in this case, the secondary sealing membrane. This arrangement allows the main structure of the tank to be firmly and flexibly fixed to the upper wall of the cover, and the cover and its fixed protrusions are made of materials that are particularly resistant to mechanical and thermal forces.

[0021] Advantageously, the first fixed protrusion and / or the second fixed protrusion have an L-shaped cross section and a linear proximal portion and a distal portion, the linear proximal portion protrudes from the upper cover wall and extends to the distal portion, the distal portion extends at an angle of 90±10° from the proximal portion, and the primary sealing membrane or the secondary sealing membrane is fixed to the distal portion, respectively.

[0022] According to a preferred embodiment, the distal portion of the first fixed protrusion and / or the second fixed protrusion has a Γ or C contour.

[0023] This cross-section provides a favorable degree of elasticity to the first fixed protrusion, which is made of a material having inherently low elastic properties but excellent mechanical and thermomechanical strength properties, and advantageously to the second fixed protrusion as well.

[0024] According to a preferred embodiment of the present invention, a structural thermal insulation material that is heat-resistant to a temperature of at least 200°C, preferably at least 120°C, more preferably at least 80°C is provided between the first fixed protrusion and the second fixed protrusion, preferably between the second fixed protrusion and the conduit.

[0025] Therefore, when a worker makes one of the welds on or near the upper wall of the cover, the first fixed protrusion and possibly the second fixed protrusion help to thermally protect this insulation, which has heat-resistant properties of its own. Thus, this insulation placed at the joint between the main structure of the tank and the liquid dome cover is unlikely to be damaged during the assembly of the liquid dome and its other components.

[0026] Accordingly, according to a preferred embodiment, the heat-resistant structural insulation material

[0027] - Glass wool or polyurethane foam surrounded by a structural cover that provides thermal protection,

[0028] - Glass wool or polyurethane foam surrounded by multiple plywood screens providing thermal protection,

[0029] - Plywood box containing glass wool or polyurethane foam that provides thermal protection,

[0030] - Plywood boxes containing glass wool or polyurethane foam surrounded at least partially by ceramic fiber, aluminum, or steel coverings,

[0031] - Glass wool or polyurethane foam surrounded by multiple plywood screens comprising at least partially ceramic fibers, aluminum, or steel coverings,

[0032] Includes

[0033] In relation to the present invention, the expression "heat-resistant structural insulation" is understood to mean that the insulation has mechanical strength characteristics that resist pressure and generally all applied stresses applied to it, thereby providing very high resistance to failure without causing plastic deformation or with little to no plastic deformation. For example, such structural insulation can withstand a pressure of at least 1 MPa (megapascal). Conversely, non-structural insulation does not have these mechanical strength characteristics or qualities.

[0034] Although the exemplary embodiments described above are not exhaustive, these insulating materials have the following technical features, ranked in order of least importance:

[0035] - Insulation function to withstand heat generated by welding,

[0036] - Sufficiently mechanically structural function for installation and fixation in a dedicated space,

[0037] - Insulation function to keep cargo cold,

[0038] - Function to reflect radiation effects,

[0039] It must have at least one of the above functions, preferably at least two of the above functions, and more preferably all of these technical functions.

[0040] Practical elements of implementing structural insulation can be combined with specific welding methods, particularly injecting cold inert gas during welding and / or providing an external heat sink during copper-bar welding.

[0041] Preferably, the lower cover wall is not fixed or connected to the first fixed protrusion. In other words, in this case, the lower cover wall is positioned at a certain distance from the end of the first fixed protrusion opposite the upper cover wall.

[0042] Preferably, with respect to this feature, the lower cover wall is not manufactured of metal or a metal-based alloy, and the lower cover wall is preferably manufactured of plywood. In fact, based on the analysis below regarding the specific technical situation of the present invention, the applicant has determined that this lower cover wall does not need to have sealing properties with respect to the fluid contained in the tank.

[0043] Advantageously, the conduit is made of an iron-based alloy comprising, by weight, 0% < C < 0.21%, 0% < Mn < 1%, 0% < Si < 0.5%, 0% < P < 0.035% and 0% < S < 0.035%, and the remainder is iron and impurities inevitably produced in the manufacture of the alloy.

[0044] Preferably, the conduit is made of steel of grades A, B, D, AH, DH, EH, FH, or E according to the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk, i.e., the IGC Code, which is well known to experts in the relevant technical field.

[0045] Advantageously, the upper cover wall as well as the first fixed protrusion and optionally the second fixed protrusion are made of an iron-based alloy comprising an austenitic steel having, by weight, 0% < C < 0.08%, 0% < Mn ≤ 2%, 0% < Si < 0.5%, 0% < P < 0.045%, 0% < S < 0.030%, 8% < Ni < 14%, 16% < Cr < 50%, 0% < N < 0.02%, optionally 0% ≤ Mo ≤ 3% and / or 0% < Ti < 0.7%, and the remainder being impurities and iron inevitably occurring in the manufacture of the alloy.

[0046] Typically, the following elements of the periodic table:

[0047] C: Carbon, Mn: Manganese, Cr: Chromium, Si: Silicon, Ni: Nickel, Co: Cobalt, P: Phosphorus, O: Oxygen, N: Nitrogen, Mo: Molybdenum, S: Sulfur, Ti: Titanium

[0048] is considered.

[0049] The present invention relates to a vessel used for transporting cold liquid products, said vessel having a double hull and a storage facility described above disposed inside said double hull.

[0050] The present invention also relates to a transfer system for cold liquid products, said system comprising the vessel described above, an insulated pipe arranged to connect a tank installed in the hull of said vessel to an external land or floating storage facility, and a pump for sending a flow of cold liquid products through said insulated pipe from said external land or floating storage facility to the tank of said vessel or from said vessel's tank to said external land or floating storage facility.

[0051] Finally, the present invention relates to a method for loading or unloading cargo on a ship described above, wherein a cold liquid product is sent through an insulated pipe from an external land or floating storage facility to a tank of the ship or from a tank of the ship to an external land or floating storage facility.

[0052] The invention can be better understood and additional objects, details, features, and advantages of the invention become clearer through the detailed description below of various specific embodiments of the invention provided merely as non-limiting examples in connection with the attached drawings. Brief explanation of the drawing

[0053] FIG. 1 is a schematic diagram of an open liquid dome in which two sides or partitions of a shaft and a conduit are visible, according to one embodiment of the present invention. Figure 2 is an enlarged cross-sectional view of the shaft and conduit surface of the liquid dome and the cover of the liquid dome. FIG. 3 is a cross-sectional view of the corner between the cover, the conduit, and the liquid dome shaft, showing the first fixed protrusion and the second fixed protrusion in particular. FIG. 4 is a schematic cross-sectional view functionally illustrating the corner portion between the cover, the conduit, and the liquid dome shaft. Figure 5 is an enlarged view of the corner portion shown in Figure 4. FIG. 6 is a schematic diagram similar to FIG. 1, in which the first fixed protrusion and the second fixed protrusion can be seen in particular. FIG. 7 is a schematic diagram supplementing FIG. 6 with some additional components. FIG. 8 is a schematic diagram supplementing FIG. 6 with some additional components. FIG. 9 is a cut-away schematic view showing the interior of the storage facility of a liquefied natural gas carrier and the cargo loading / unloading terminal for this tank. Specific details for implementing the invention

[0054] In this specification, the term "vertical" means extending in the direction of the Earth's gravitational field. In this specification, the term "horizontal" means extending in a direction perpendicular to the vertical direction.

[0055] When the storage facility (1) is located on a vessel such as a liquefied natural gas carrier, the load-bearing structure (not shown in the attached drawings) is formed by the double hull of the vessel. The upper outer load-bearing wall (5) is called the outer deck (5) of the vessel.

[0056] The tank (71) comprises a main structure formed by a bottom wall (not shown), a ceiling wall, two cofferdam walls (not shown in the attached drawings) positioned at the front and rear when the storage facility (1) is placed on a ship and the bottom wall is connected to the ceiling wall, two side walls (not shown), and optionally two to four bevel walls (not shown) connecting the side walls to the bottom wall or the ceiling wall (not shown in the attached drawings). Thus, the walls of the tank (71) are connected to each other to form a polyhedral structure and to define the internal storage space (9).

[0057] In order to load and unload liquefied gas into and out of the tank (71), particularly to allow a loading / unloading pipe (not shown in the attached drawing) to reach the bottom of the tank (71) by passing through the loading / unloading opening (10), the storage facility (1) includes an upper external load-bearing wall (5), an upper internal load-bearing wall, and a loading / unloading opening (10) that locally interrupts the ceiling wall of the tank (71).

[0058] The storage facility (1) also includes a pump (not shown) as well as a loading / unloading tower (not shown in the attached drawings) positioned at the same height as the opening (10) and inside the tank (71) to form a load-bearing structure for the loading / unloading pipe over the entire height of the tank (71).

[0059] Additionally, the storage facility (1) has a cover (12) that is positioned at a loading / unloading opening (10) and closes the internal storage space at the opening (10). The cover (12) includes an orifice to allow a loading / unloading pipe to pass through the cover (12).

[0060] The tank (71) has a shaft (15) that is positioned in the main structure at the opening and allows the tank wall to extend continuously from the inner deck to the outer deck (5), where the wall is interrupted by the loading / unloading opening (10). In a liquefied gas storage tank, the shaft (15) equipped with the cover (12) is referred to as a liquid dome.

[0061] The loading / unloading opening (10) and shaft (15) typically have a rectangular outline. Thus, the shaft (15) includes four walls, one of which is an extension of the rear cofferdam wall (8) (as shown in FIG. 1), and the other three are connected to the ceiling wall to form a 90° angle with the ceiling wall.

[0062] According to the present invention, a cover (12) is placed on an outer deck (5) to close the shaft (15). The tank (71) is a membrane tank (71) designed to store liquefied gas. The main structure of the tank (71) has a multilayer structure including a secondary insulation barrier (16) containing an insulation element in contact with a load-bearing structure from the outside to the inside, a secondary sealing membrane (17) in contact with the secondary insulation barrier (16), a primary insulation barrier (18) containing an insulation element in contact with the secondary sealing membrane (17), and a primary sealing membrane (19) designed to come into contact with the liquefied gas contained in the tank (71).

[0063] According to one embodiment, the main structure of the tank (71) is, in particular, the Mark III described in document FR 2691520 A. ® It is made using technology.

[0064] In this main structure, the secondary insulation barrier (16), the primary insulation barrier, and the secondary sealing membrane (17) are basically panels juxtaposed on a load-bearing structure that may be a structure connecting the upper internal load-bearing wall to the upper external load-bearing wall (5) at the opening (10) or an internal load-bearing structure. The secondary sealing membrane (17) is manufactured from a composite material comprising an aluminum sheet sandwiched between two sheets of glass fiber fabric. The primary sealing membrane (19) is obtained by assembling a plurality of metal plates welded together along the edges and having two corrugations extending in perpendicular directions. The metal plates are made of stainless steel or aluminum sheets formed, for example, by bending or stamping. The primary sealing membrane (19) is illustrated particularly in FIGS. 3 and FIGS. 4.

[0065] Further details of these corrugated metal membranes are described specifically in FR 2861060 A.

[0066] In the shaft (15), the upper portion of the primary sealing membrane (19) is fixed to the fixed protrusion (50), more specifically to the end portion (52) of the fixed protrusion (50). The connection between the fixed protrusion (50) and the primary membrane (19) is preferably formed by sealing welding or possibly by adhesion.

[0067] The cover (12) is also made of a multilayer structure including, from the outside to the inside, an upper cover wall (23), a lower cover wall (22), and an insulating structure (24) disposed between the lower cover wall (22) and the upper cover wall (23). The cover (12) also has a reinforcing member (25) disposed on the upper cover wall (23).

[0068] The cover (12) is positioned in the loading / unloading opening (10) such that the upper cover wall (23) is positioned on the plane of the upper outer load-bearing wall (5) or the outer deck (5). Accordingly, the storage facility (1) does not have a dome seat in this case, and the cover (12) does not protrude over the outer deck (5).

[0069] Since the applicant has confirmed the feasibility of using a single sealing membrane in the cover (12), the upper cover wall (23) is fixed to the outer deck (5) so as to be sealed over the entire opening (10) so that the upper cover wall (23) acts as a secondary sealing membrane (17) in the cover (12), or more simply as a sealing membrane. The upper cover wall (23) is made of a metal material, for example, stainless steel.

[0070] According to one important embodiment of the present invention, the lower cover wall (22) is advantageously made of a non-metallic material or a metal alloy. In fact, the applicant has confirmed that such a wall (22) does not necessarily have to be a sealing membrane. Additionally, the lower cover wall (22) is advantageously made of plywood, but if the material can withstand mechanical and chemical contact with the cold fluid contained in the tank (71), the wall (22) may be made of plastic or a composite (e.g., a "sandwich" structure), and preferably may be made of thermosetting plastic.

[0071] As illustrated in FIGS. 4 and 5, there is no connection here between the lower cover wall (22) and the first fixed protrusion (50) or the primary sealing membrane (19). Therefore, there may be an opening or gap between the lower cover wall (22) and the primary sealing membrane (19). Again, the applicant has confirmed that a connection between the lower cover wall (22) and the primary sealing membrane (19) is not required.

[0072] The insulating structure (24) of the cover (12) comprises a plurality of intersecting insulating elements that may have similar or different configurations. In a preferred embodiment, these insulating elements placed at the same height as the lower cover wall (22) are structural insulating elements, whereas insulating elements placed around the insulating structure (24), i.e., insulating elements not placed between the lower cover wall (22) and the upper cover wall (23), are non-structural insulating elements. Naturally, structural insulating elements may be provided between the lower cover wall (22) and the upper cover wall (23) if desired, taking into account the mechanical stress of the assembly. Structural insulating elements may optionally be fiber-reinforced high-density polymer foam blocks, plywood, or composite boxes filled with insulating fillers such as glass wool or perlite. Non-structural insulating elements may be low-density polymer foam blocks or glass wool.

[0073] However, one important embodiment of the present invention is

[0074] - First, a first fixed protrusion (50) and a second fixed protrusion (55), referred to as an insulating material (40), and

[0075] - Secondly, the second fixed protrusion (55) and the conduit (30), referred to as the insulating material (41)

[0076] This concerns the insulation material (40, 41) provided between them.

[0077] This insulation material (40, 41) is a structural insulation material. Additionally, this insulation material (40, 41) has heat resistance to a temperature of at least 200°C (Celsius), preferably at least 80°C. This means that when this insulation material (40, 41) is exposed to the above temperature, the mechanical properties of this insulation material (40, 41) do not change or change very little. Therefore, the possible types and functions of this insulation material (40, 41) described above are essentially capable of perfectly withstanding the intense heat generated by welding work performed nearby. Naturally, as described above, welding work may involve measures to thermally protect this insulation material (40, 41), particularly during welding, by injecting a cold inert gas and / or by providing an external heat sink during copper-bar welding.

[0078] The fixed protrusion (50) protrudes from the upper cover wall (23), extends vertically, and includes a vertical proximal portion (51) and a distal portion (52) that extends generally horizontally or, in this case, forms a C-shaped loop, but the distal portion (52) may have a Γ-shaped contour. The fixed protrusion (50) is preferably made of the same material as the upper cover wall (23). Thus, the fixed protrusion (50) is made of a metallic material, typically an iron-based alloy, which has superior mechanical strength compared to conventional carbon steel (e.g., carbon steel of the conduit (30)) when the ambient temperature is significantly lower than 0°C or even -40°C or lower.

[0079] Another important embodiment of the present invention is that there is a second fixing protrusion (55) protruding from the wall (23) used to securely seal the secondary sealing membrane (17). Thus, within the scope of the present invention, each of the two sealing membranes (17, 19) has an independent sealing connection to the upper cover wall (23) by a particularly advantageous fixing protrusion (50, 55) that provides high mechanical strength and some degree of flexibility, thereby allowing the protrusion to easily absorb various thermodynamic stresses present in a very specific area where the protrusion is a liquid dome.

[0080] The second fixed protrusion (55), like the first fixed protrusion (50), includes a proximal portion (56) and a distal portion (57) extending the proximal portion (56), to which the second sealing membrane (17) is fixed. The distal portion (57) of the second fixed protrusion (55) has a C-shaped ring contour, but the distal portion (52) may have a Γ-shaped contour. The distal portion (57) may advantageously be identical in shape and / or size to the distal portion (52) of the first fixed protrusion (50).

[0081] Advantageously, the proximal portion (56) of the second fixed protrusion (55) is at least twice as long as the proximal portion (51) of the first fixed protrusion (50). This feature causes the connection of the wall (23) to the primary sealing membrane (19) to have greater rigidity than the connection of the wall (23) to the secondary sealing membrane (17), that is, provides greater flexibility in the connection between the wall (23) and the secondary sealing membrane (17) than in the connection between the wall (23) and the primary sealing membrane (19). Generally, it is important that the proximal portion (56) be longer than the proximal portion (51) to enable assembly.

[0082] It should be noted here that the present invention is primarily about a first fixed protrusion (50) and directly connecting the first fixed protrusion (50) to a primary sealing membrane (19). Accordingly, in an alternative embodiment (not shown in the attached drawings), the second fixed protrusion (55) is not present, and the fixed protrusion (50) additionally includes an arm or flange to secure the fixed protrusion (50) to be sealed to the secondary sealing membrane (17).

[0083] The upper cover wall (23) and these fixed protrusions (50, 55) may be manufactured from 300-series stainless steel permitted by the IGC code. In other words, the fixed protrusions (50, 55) are manufactured from austenitic steel according to ASTM A240.

[0084] The present invention is based first on the fact that the presence of a first fixed protrusion (50) and possibly a second fixed protrusion (55) allows the conduit (30) forming the shaft (15) of the liquid dome to be manufactured of carbon steel, particularly steel of grades A, B, D, AH, DH, EH, FH, or E according to ASTM standard A131. These grades of steel lose resistance or elasticity when the ambient temperature drops significantly below 0°C, which is a possible or certain risk in liquefied gas tanks, but these steels are much cheaper than stainless steel.

[0085] Therefore, this arrangement reduces the amount of expensive stainless steel in the liquid dome and provides flexibility to the primary anchor, i.e., the primary sealing membrane (19) in the opening (10) of the liquid dome, and the secondary anchor, i.e., the secondary sealing membrane (17).

[0086] Accordingly, a primary embodiment of the present invention is in connection and fixation with the fixed protrusion (50) of the primary sealing membrane (19) of the liquid dome, and advantageously in connection and fixation with the fixed protrusion (55) of the secondary sealing membrane (17) of the liquid dome.

[0087] Additionally, as described above, these fixed protrusions (50, 55) are offset from the conduit (30) of the shaft (15) of the liquid dome by at least several centimeters, i.e., 5 cm to 60 cm, preferably 15 cm to 40 cm, from the conduit (30). Bearing in mind that when the structure carrying the tank (71) is a ship, the vertically positioned section of the shaft (15) of the liquid dome, which is much smaller or narrower than the tank (71), concentrates strong mechanical stress and deformation, this offset of these fixed protrusions (50, 55) from the conduit (30) provides flexible fixation of the membrane (17, 19) so that the assembly can easily withstand significant mechanical stress.

[0088] As illustrated in the attached drawing, the offset of the fixed protrusion (50) from the conduit (30) reduces the need for structural insulation, which is more expensive and difficult to place than other non-structural insulation. Only structural insulation (40, 41) placed between the fixed protrusion (50, 55) and the partition (30), respectively, is required.

[0089] Accordingly, in the liquid dome structure according to the present invention, the amount of structural insulation can be reduced compared to a conventional liquid dome that does not include a fixed protrusion (50) and possibly a fixed protrusion (55).

[0090] FIG. 9 illustrates an exemplary offshore terminal comprising a loading / unloading point (75), a seabed pipe (76), and a land facility (77). The loading / unloading point (75) is a fixed offshore facility comprising a movable arm (74) and a column (78) that supports the movable arm (74). The movable arm (74) supports a bundle of insulated hoses (79) that can be connected to a loading / unloading pipe (73). The directional movable arm (74) can be adjusted to fit liquefied natural gas carriers of all sizes. A connecting pipe (not shown) extends into the column (78). The loading / unloading point (75) enables the loading and unloading of cargo to or from the land facility (77) of the liquefied natural gas carrier (70). This facility has a liquefied gas storage tank (80) and a connecting pipe (81) connected to a loading / unloading point (75) through a seabed pipe (76). The seabed pipe (76) enables the transport of liquefied gas over a long distance, for example, 5 km, between the loading / unloading point (75) and the onshore facility (77), which enables the liquefied natural gas carrier (70) to be kept away from the coast during loading and unloading operations.

[0091] To generate the pressure required to transport the liquefied gas, a pump mounted on the ship (70) and / or a pump installed on the land facility (77) and / or a pump installed at the loading / unloading point (75) is used.

[0092] Although the present invention has been described with respect to various specific embodiments, it is obvious that the invention is not limited thereto and includes all technical equivalents of the described means and combinations thereof that fall within the scope of the invention.

[0093] The use of the verbs "consists of" or "includes" and their conjugations does not exclude the existence of other elements or other stages other than those described in the claims.

[0094] In the scope of claims, reference symbols in parentheses should not be understood as limiting the scope of claims.

Claims

Claim 1 A storage facility (1) for liquefied gas comprising a load-bearing structure and a sealed insulating tank (71) disposed inside the load-bearing structure, wherein the sealed insulating tank (71) has a main structure formed by a plurality of interconnected tank walls that are fixed to the load-bearing structure, the main structure defines an internal storage space, the main structure includes at least one sealing membrane (17, 19) and at least one insulating barrier (16, 18), the insulating barrier (16, 18) is positioned between the sealing membrane (17, 19) and the load-bearing structure, the load-bearing structure has a flat upper load-bearing wall, and the sealing membrane (17, 19) and the insulating barrier (16, 18) of the main structure and the upper load-bearing A storage facility (1) wherein the wall is locally interrupted, the tank (71) has a cover (12) disposed in the loading / unloading opening (10), and the cover (12) comprises an upper cover wall (23), a lower cover wall (22), and an insulating structure (24) disposed between the lower cover wall (22) and the upper cover wall (23), wherein the conduit (30) and the upper cover wall (23) are made of different iron-based alloys, and at least a first fixed protrusion (50) protruding from the upper cover wall (23) is fixed to be sealed to the sealing membrane (19). Claim 2 A storage facility (1) according to claim 1, wherein the sealing membrane (17, 19) comprises a primary sealing membrane (19) and then a secondary sealing membrane (17) extending from the interior of the internal storage space or conduit (30) to the exterior of the tank (71), and at least one second fixed protrusion (55) protruding from the upper cover wall (23) is fixed to be sealed to the secondary sealing membrane (17). Claim 3 A storage facility (1) characterized in that, in paragraph 2, the first fixed protrusion (50) and the second fixed protrusion (55) are independent of each other. Claim 4 A storage facility (1) characterized in that, in claim 2 or 3, the first fixed protrusion (50) and / or the second fixed protrusion (55) have an L-shaped cross section and a linear proximal portion (51) and a distal portion (52), the linear proximal portion (51) protrudes from the upper cover wall (23) and extends to the distal portion (52), the distal portion (52) extends from the proximal portion (51) at an angle of 90±10°, and the primary sealing membrane or the secondary sealing membrane is respectively fixed to the distal portion. Claim 5 A storage facility (1) characterized in that, in paragraph 4, the distal portion of the first fixed protrusion and / or the second fixed protrusion has a Γ or C contour. Claim 6 A storage facility (1) characterized in that, in paragraph 2 or 3, a heat-resistant structural insulation material is provided between the first fixed protrusion (50) and the second fixed protrusion (55), or between the second fixed protrusion and the conduit (30). Claim 7 In claim 6, the heat-resistant structural insulation material comprises: glass wool or polyurethane foam surrounded by a structural cover providing thermal protection; glass wool or polyurethane foam surrounded by a plurality of plywood screens providing thermal protection; a plywood box containing glass wool or polyurethane foam providing thermal protection; a plywood box containing glass wool or polyurethane foam surrounded by a ceramic fiber, aluminum or steel cover; and glass wool or polyurethane foam surrounded by a plurality of plywood screens including a ceramic fiber, aluminum or steel cover. Storage facility (1). Claim 8 A storage facility (1) characterized in that, in any one of claims 1 to 3, the lower cover wall (22) is not fixed or connected to the first fixed protrusion. Claim 9 A storage facility (1) characterized in that, in any one of claims 1 to 3, the lower cover wall (22) is not made of metal or a metal-based alloy, or the lower cover wall (22) is made of plywood. Claim 10 A storage facility (1) characterized in that, in any one of claims 1 to 3, the conduit (30) is made of an iron-based alloy comprising, by weight, 0% < C < 0.21%, 0% < Mn < 1%, 0% < Si < 0.5%, 0% < P < 0.035% and 0% < S < 0.035%, and the remainder is impurities inevitably produced in the manufacture of the alloy and iron. Claim 11 In claim 10, the storage facility (1) is characterized in that the above conduit (30) is made of steel of grade A, B, D, AH, DH, EH, FH, or E according to the IGC code. Claim 12 A storage facility (1) characterized in that, in addition to the upper cover wall (23), the first fixed protrusion (50) or the second fixed protrusion (55) is made of an iron-based alloy comprising an austenitic steel having, by weight, 0% < C < 0.08%, 0% < Mn ≤ 2%, 0% < Si < 0.5%, 0% < P < 0.045%, 0% < S < 0.030%, 8% < Ni < 14%, 16% < Cr < 50%, 0% < N < 0.02%, and the remainder being impurities inevitably generated during the manufacture of the alloy. Claim 13 A vessel (70) used for transporting cold liquid products, characterized by having a double hull (72) and a storage facility (1) according to any one of claims 1 to 3 disposed inside the double hull. Claim 14 A transfer system for cold liquid products, comprising a vessel (70) according to claim 13, an insulating pipe (73, 79, 76, 81) arranged to connect a tank (71) installed in the hull of the vessel to an external land or floating storage facility (77), and a pump for sending a flow of cold liquid products through the insulating pipe from the external land or floating storage facility to the tank of the vessel or from the tank of the vessel to the external land or floating storage facility. Claim 15 A method for loading or unloading cargo on a vessel (70) according to paragraph 13, characterized in that a cold liquid product is sent from an external land or floating storage facility (77) to a tank (71) of the vessel or from a tank (71) of the vessel to an external land or floating storage facility (77) through an insulating pipe (73, 79, 76, 81).

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