Liquefied gas cargo tank

Abstract

A liquefied gas cargo tank is disclosed. A liquefied gas cargo tank according to an embodiment of the present invention comprises: a primary barrier including a plurality of corrugated parts of the same size but differing directional orientation, and an intersection part that is intersected by the differently oriented corrugated parts; and an insulation panel assembly surrounding the primary barrier, wherein the insulation panel assembly comprises differently angled first and second corner panels provided in the corners of the hull, and, in accordance to the angles of the first and second corner panel units, the primary barrier can be installed so as to have differing rigidity based on the orientation of the corrugated parts.

Description

liquefied gas cargo tank

[0001] The present invention relates to a liquefied gas cargo tank, and more specifically, to a liquefied gas cargo tank designed to be optimized by considering the load characteristics of a primary barrier provided inside the hull.

[0002] Liquefied natural gas (LNG) is a colorless, transparent, ultra-low temperature liquid produced by cooling natural gas, which is mainly composed of methane, to -163°C to reduce its volume to one-six hundredth of its original size. As this liquefied natural gas has emerged as an energy resource, efficient transportation methods have been considered to transport this gas in large quantities from production sites to demand sites.

[0003] As part of these efforts, liquefied natural gas carriers capable of transporting large quantities of liquefied natural gas by sea have emerged. These carriers must be equipped with cargo tanks capable of storing liquefied natural gas liquefied at ultra-low temperatures, but there have been many difficulties due to the very stringent requirements for these cargo tanks. Specifically, since liquefied natural gas has a vapor pressure higher than atmospheric pressure and a boiling point of approximately -163°C, in order to safely store and store this liquefied natural gas, the cargo tanks must be constructed from materials capable of withstanding ultra-low temperatures, such as aluminum steel, stainless steel, or 36% nickel steel, and must also be designed with a unique insulation structure that is resistant to thermal stress and thermal shrinkage and prevents heat intrusion.

[0004] Since the metal membrane, which serves as the primary barrier of the cargo tank, comes into direct contact with LNG at a cryogenic temperature of -163°C, metal materials resistant to low-temperature brittleness, such as aluminum alloy, Invar, and 9% nickel steel, are used to withstand stress changes. It is manufactured in a roughly rectangular shape, and straight corrugations with a raised central section are formed across the entire metal panel to facilitate expansion and contraction in response to repeated temperature changes and load changes of the stored liquid. The corners and four sides of multiple membrane metal panels overlap with the corners and four sides of adjacent membranes and are connected to each other by overlapping welding to maintain the airtightness of the tank.

[0005] This embodiment aims to provide a liquefied gas cargo tank designed to be optimized by considering the load and stiffness characteristics of the primary barrier.

[0006] The present embodiment aims to provide a liquefied gas cargo tank that can reduce the number of components constituting the liquefied gas cargo tank.

[0007] This embodiment aims to provide a liquefied gas cargo tank capable of reducing material and installation costs.

[0008] According to one aspect of the present invention, a liquefied gas cargo tank may be provided, comprising: a primary barrier including a plurality of corrugated portions arranged in different directions and an intersection portion where the corrugated portions in different directions intersect; and an insulating panel assembly surrounding the primary barrier, wherein the insulating panel assembly is installed at a corner portion of the hull and includes a first corner panel portion and a second corner panel portion formed at different angles, and the primary barrier is installed differently in correspondence with the angles of the first corner panel portion and the second corner panel portion.

[0009] The above primary barrier includes a first corrugated section and a second corrugated section that intersect each other, and at the intersection, the height of the first corrugated section may be formed higher than the height of the second corrugated section.

[0010] The first wrinkle portion may include a pair of concave portions formed on both sides of the intersection portion.

[0011] The first corner panel section may be installed in a first corner section formed by the bottom surface and the first side of the hull intersecting at a first angle, and the second corner panel section may be installed in a second corner section formed by the bottom surface and the second side of the hull intersecting at a second angle.

[0012] The first angle above can be formed larger than the second angle above.

[0013] The first corner panel portion may have a primary barrier including a first corrugated portion formed along the first angle.

[0014] The above second corner panel portion may have a primary barrier including a second corrugated portion formed along the second angle.

[0015] The first angle above may be an obtuse angle, and the second angle above may be a right angle.

[0016] The above insulation panel assembly may further include flat panel sections installed on the bottom surface and side surface of the hull, respectively.

[0017] The above insulation panel assembly may further include a fastening part for fixing the first corner panel part and the second corner panel part.

[0018] This embodiment provides a liquefied gas cargo tank designed to be optimized by considering the load and stiffness characteristics of the primary barrier.

[0019] The present embodiment provides a liquefied gas cargo tank that can reduce the number of components constituting the liquefied gas cargo tank.

[0020] This embodiment provides a liquefied gas cargo tank that can reduce material and installation costs.

[0021] FIG. 1 is a perspective view showing a liquefied gas cargo tank structure according to one embodiment of the present invention.

[0022] FIG. 2 is a perspective view showing a primary barrier according to one embodiment of the present invention.

[0023] Figure 3 is a cross-sectional view of AA of Figure 2.

[0024] FIG. 4 is a perspective view showing a primary barrier disposed in a first corner panel portion according to one embodiment of the present invention.

[0025] FIG. 5 is a perspective view showing a primary barrier disposed in a second corner panel portion according to one embodiment of the present invention.

[0026] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following embodiments are presented to sufficiently convey the concept of the present invention to those skilled in the art to which the present invention pertains. The present invention is not limited to the embodiments presented herein and may be embodied in other forms. In order to clarify the present invention, the drawings may omit the illustration of parts unrelated to the description and may slightly exaggerate the size of components to aid understanding.

[0027] FIG. 1 is a perspective view showing a liquefied gas cargo tank structure according to one embodiment of the present invention.

[0028] FIG. 2 is a perspective view showing a primary barrier according to one embodiment of the present invention.

[0029] Figure 3 is a cross-sectional view of AA of Figure 2.

[0030] Referring to FIGS. 1 to 3, a liquefied gas cargo tank according to one embodiment of the present invention may largely include a primary barrier (100) that comes into direct contact with the liquefied gas and an insulating panel assembly (200).

[0031] The primary barrier (100) is made of a flexible metal material and is composed of a membrane, which can be formed by combining multiple sheets, and welding can be used as a joining method to maintain airtightness. Various materials can be used for the membrane, but generally, SUS (stainless steel) material can be used.

[0032] The primary barrier (100) may include a first corrugated section (110) in a first direction and a second corrugated section (120) in a second direction that are arranged in different directions and have the same size to facilitate shrinkage or expansion due to thermal deformation while maintaining airtightness, and an intersection section (130) where the two corrugated sections (110, 120) intersect. In this case, the same size refers to the length, width, and height of the corrugated sections (110, 120) being the same.

[0033] Meanwhile, in FIG. 2, two directions of corrugations (110, 120) arranged vertically are shown, but three or more directions of corrugations may be included as needed. For example, three directions of corrugations may be arranged at an angle of 60 degrees to each other.

[0034] The first corrugated portion (110) is formed in a first direction and can eliminate thermal deformation occurring in a second direction due to the elasticity of the first corrugated portion (110), and the second corrugated portion (120) is formed in a second direction and can eliminate thermal deformation occurring in a first direction due to the elasticity of the second corrugated portion (120). At this time, the first direction may be the y-axis direction with respect to FIG. 1, and the second direction may be the x-axis direction.

[0035] The intersection (130) is a region where the first wrinkle section (110) and the second wrinkle section (120) intersect. The intersection (130), the first wrinkle section (110), and the second wrinkle section (120) are not separated by a physical boundary. For convenience, the wrinkles extending in a straight line shape in the first direction or the second direction are designated as the wrinkle sections (110, 120), and the region where wrinkle sections of different directions converge at the point where these wrinkle sections (110, 120) intersect is designated as the intersection (130).

[0036] At the intersection (130), the height of the first corrugated section (110) may be formed higher than that of the second corrugated section (120). That is, at the intersection (130), the first corrugated section (110) may be formed to pass over the upper part of the second corrugated section (120), and the height of the first corrugated section (110) in the area excluding the intersection (130) may be formed to be the same as the height of the second corrugated section (120).

[0037] Centered on the intersection (130), the first fold (110) may include a pair of concave portions (111) formed on both sides of the intersection (130).

[0038] The concave portion (111) is formed in the z-axis direction based on FIG. 1, but can be formed to be sunken in a direction opposite to the direction in which the first wrinkle portion (110) is formed protruding in the z-axis direction.

[0039] That is, the concave portion (111) may be formed on the first corrugated portion (110) and may be formed as a pair on both sides of the intersection portion (130), and the height (h) of the first corrugated portion (110) at the intersection portion (130) may be formed higher than the height (h1) of the first corrugated portion (110) at the portion excluding the intersection portion (130). Through this, the load generated at each corrugated portion (110, 120) of the primary barrier (100) and the stiffness of each corrugated portion (110, 120) may be different from each other, and thus enable the application of an optimized design change for the liquefied gas cargo tank accordingly.

[0040] Below, before describing these optimized design changes, we will first describe the insulation panel assembly (200).

[0041] The insulation panel assembly (200) is arranged to surround the aforementioned primary barrier (100) to block heat transfer between the interior of the liquefied gas cargo tank and the inner wall (1) of the hull.

[0042] Referring again to FIG. 1, the insulation panel assembly (200) may include a lower insulation board (210), a secondary barrier (220), and an upper insulation board (230) that are sequentially stacked and fixed from the inner wall (1) of the hull.

[0043] The upper insulation board (230) absorbs fluid impact forces, such as sloshing, applied to the primary barrier (100) and performs a heat dissipation function to prevent the internal temperature of the cargo hold from being transferred to the inner wall (1) of the hull. This upper insulation board (230) includes an insulation foam made of reinforced polyurethane foam (RPUF), which is a composite material with enhanced rigidity produced by using high-density liquid polyurethane and glass fiber together and injecting them into a laminator, or a low-density polyurethane foam (PUF) with excellent thermal insulation performance.

[0044] The secondary barrier (220) is interposed between the upper insulation board (230) and the lower insulation board (210) to perform a buffering function and, at the same time, prevents liquefied gas stored inside the cargo tank from leaking out if the primary barrier (100) is damaged. This secondary barrier (220) can be formed by connecting a plurality of barrier sheets made of metal materials such as Invar alloy, stainless steel (SUS), or aluminum alloy.

[0045] The lower insulation board (210) absorbs fluid impact forces, such as sloshing, applied to the primary barrier (100) and performs a heat dissipation function to prevent the internal temperature of the cargo hold from being transferred to the inner wall (1) of the hull. This lower insulation board (210) includes an insulation foam made of reinforced polyurethane foam (R-PUF) or low-density polyurethane foam (PUF) with excellent insulation performance to form a double insulation structure together with the upper insulation board (230).

[0046] The lower insulation board (210) may be formed by arranging unit lower insulation boards in a grid shape. The unit lower insulation boards may be fixed by stud bolts installed on the inner wall (1) of the hull while arranged in a grid shape. The unit lower insulation board includes a lower insulation foam (not shown) formed of reinforced polyurethane foam or polyurethane foam, an upper reinforcing panel (not shown) attached to the upper surface of the lower insulation foam, and a lower reinforcing panel (not shown) attached to the lower surface of the lower insulation foam. The upper reinforcing panel and the lower reinforcing panel may be made of plywood, etc., and may be firmly fixed to each other by an adhesive such as epoxy glue or fastening members such as bolts and rivets, respectively, on the upper and lower surfaces of the lower insulation foam.

[0047] Meanwhile, the hull includes a bottom surface (10) and a side surface (20), and the side surface (20) includes a first side surface (21) and a second side surface (22). The portion where one or more of the bottom surface (10), the first side surface (21), and the second side surface (22) meet forms the edge of the hull. Hereinafter, the portion where one or more of the bottom surface (10), the first side surface (21), and the second side surface (22) fold is referred to as a corner portion (30).

[0048] The corner section (30) may include a first corner section (31) formed by the bottom surface (10) and the first side (21) of the hull intersecting at a first angle, and a second corner section (32) formed by the bottom surface (10) and the second side (22) of the hull intersecting at a second angle.

[0049] An insulation panel assembly (200) is installed for insulation of the hull, and the insulation panel assembly (200) may include a first corner panel section (201) and a second corner panel section (202) formed at different angles corresponding to the angle of the hull corner section (30).

[0050] The first corner panel section (201) is installed on the first corner section (31) formed at a first angle, and the second corner panel section (202) is installed on the second corner section (32) formed at a second angle. That is, the first corner panel section (201) has a first angle, and the second corner panel section (202) can have a second angle.

[0051] The first angle may be formed to be larger than the second angle. Specifically, the first angle may be obtuse, and the second angle may be right. In this case, the first angle may vary from 90 degrees to 180 degrees, but below, the case of 135 degrees will be used as an example.

[0052] In a liquefied gas cargo tank according to one embodiment of the present invention, the primary barrier (100) can be installed differently in correspondence with the first corner panel section (201) and the second corner panel section (202) formed at angles to each other. Specifically, the primary barrier (100) can be installed to provide a difference in rigidity according to the arrangement direction of the aforementioned corrugated sections (110, 120) in correspondence with the angles of the first corner panel section (201) and the second corner panel section (202).

[0053] As described above, due to the structural characteristics of the primary barrier (100) according to one embodiment of the present invention, the load generated in the second corrugated section (120) may be greater than the load generated in the first corrugated section (110), and the direction horizontal to the second corrugated section (120) may have stronger rigidity compared to the direction horizontal to the first corrugated section (110). By utilizing these characteristics, the arrangement method of the corrugated sections (110, 120) can be optimized according to the angle between the first corner panel section (201) and the second corner panel section (202).

[0054] FIG. 4 is a perspective view showing a primary barrier disposed in a first corner panel portion according to one embodiment of the present invention.

[0055] FIG. 5 is a perspective view showing a primary barrier disposed in a second corner panel portion according to one embodiment of the present invention.

[0056] Referring to FIGS. 4 and 5, the first corner panel section (201) may be configured to have a primary barrier (100) including a first corrugated section (110) formed along a first angle, and the second corner panel section (202) may be configured to have a primary barrier (100) including a second corrugated section (120) formed along a second angle.

[0057] That is, in the first corner panel section (201) formed at a first angle which is obtuse, a first barrier (100) can be arranged so that the first corrugated section (110) forms the first angle. Through this, a relatively small load is generated, and as a result, the number of fastening sections (203) installed on the first corner panel section (201) can be reduced.

[0058] Additionally, a first barrier (100) can be positioned so that the second corrugated section (120) forms the second angle in the second corner panel section (202) formed at a right angle. By doing so, the second corrugated section (120), which has relatively high rigidity, is positioned in the second corner panel section (202), thereby preventing an increase in the number of fastening sections (203) of the second corner panel section (202) due to increased load.

[0059] Meanwhile, the fastening part (203) is for fixing the first corner panel part (201) and the second corner panel part (202), and although not illustrated, the fastening part (203) may include a connecting bolt and a fastening unit. The connecting bolt is vertically connected to the upper insulation board (230) of the first corner panel part (201) and the second corner panel part (202), and is mechanically connected to fix the upper insulation board (230) that is stacked on the secondary barrier (220).

[0060] The insulation panel assembly (200) may further include flat panel sections (203) installed on the bottom surface and sides of the hull, respectively.

[0061] The flat panel section (203) may be composed of a plurality of flat panel units, and the number and size of each flat panel unit are not limited. Meanwhile, the flat panel section (203) is installed in a flat shape in a flat area such as the bottom surface (10) and side surface (20), rather than the corner section (30) of the hull, and the specific structure is the same as described above.

[0062] A liquefied gas cargo tank according to one embodiment of the present invention can have the effect of reducing material costs and improving productivity by reducing the number of parts through optimizing the design by considering the load characteristics according to the shape of each corrugated portion (110, 120) of the primary barrier (100).

Claims

1. A primary barrier comprising a plurality of corrugated portions having the same size and arranged in different directions, and an intersection portion where the corrugated portions in different directions intersect; and It includes an insulation panel assembly surrounding the above-mentioned primary barrier, and The above insulation panel assembly is It includes a first corner panel section and a second corner panel section installed at different angles at the corner section of the hull, A liquefied gas cargo tank in which the primary barrier is installed to provide a difference in rigidity according to the arrangement direction of the corrugated portion in correspondence with the angle between the first corner panel portion and the second corner panel portion.

2. In Paragraph 1, The above primary barrier is It includes a first corrugated portion and a second corrugated portion that intersect each other, A liquefied gas cargo tank in which the height of the first corrugated section at the above intersection is formed higher than the height of the second corrugated section.

3. In Paragraph 2, The above first folded part A liquefied gas cargo tank comprising a pair of concave portions formed on both sides of the above-mentioned intersection.

4. In Paragraph 3, The above-mentioned first corner panel is installed in the first corner formed by the bottom surface and the first side of the hull intersecting at a first angle, and The above-mentioned second corner panel section is a liquefied gas cargo tank installed in a second corner section formed by the bottom surface and the second side of the hull intersecting at a second angle.

5. In Paragraph 4, A liquefied gas cargo tank in which the first angle is formed to be larger than the second angle.

6. In Paragraph 5, The above first corner panel part A liquefied gas cargo tank having a primary barrier including a first corrugated portion formed along the first angle.

7. In Paragraph 5, The above second corner panel part A liquefied gas cargo tank having a primary barrier including a second corrugated portion formed along the second angle.

8. In Paragraph 5, The first angle mentioned above is an obtuse angle, and The above second angle is a right angle liquefied gas cargo tank.

9. In Paragraph 1, The above insulation panel assembly is A liquefied gas cargo tank further comprising flat panel sections installed on the bottom surface and side surface of the hull, respectively.

10. In Paragraph 1, The above insulation panel assembly is A liquefied gas cargo tank further comprising a fastening part for fixing the first corner panel part and the second corner panel part.

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