WO2016162908A1

WO2016162908A1 - Tank for liquefied gas for vessels, and liquified gas carrying vessel provided with same

Info

Publication number: WO2016162908A1
Application number: PCT/JP2015/005184
Authority: WO
Inventors: 直哉松原; 謙太森長; 巧吉田; 孝昭清末
Original assignee: 川崎重工業株式会社
Priority date: 2015-04-08
Filing date: 2015-10-13
Publication date: 2016-10-13
Also published as: CN107428400A; JP6461686B2; KR102010422B1; CN107428400B; KR20170130536A; JP2016199092A

Abstract

This tank for liquefied gas for vessels is a pressure vessel that is symmetrical about the vertical central axis, and includes: an upper tank body that has a lower end opening downward; and a lower tank body that has an upper end opening upward. The vertical sectional shape of one of the upper tank body and the lower tank body passing through the central axis matches a locus represented by the following formula (1): |x/r₁|^m+ |y/r₂|^m= 1 (1), where: r₁ is the radius of the upper end or lower end of the one tank body; r₂ is the height of the one tank body; and m is a constant satisfying 2<m<3.

Description

Marine liquefied gas tank and liquefied gas carrier equipped with the same

The present invention relates to a marine liquefied gas tank that stores liquefied gas and a liquefied gas carrier equipped with the marine liquefied gas tank.

Conventionally, in order to transport liquefied gas such as liquefied natural gas (hereinafter referred to as “LNG”), a liquefied gas carrier ship equipped with a plurality of liquefied gas tanks has been used. As a liquefied gas tank mounted on a liquefied gas carrier ship, for example, an independent spherical tank, a membrane type tank, and the like are known. For example, Patent Document 1 discloses an independent spherical tank (hereinafter referred to as “spherical tank”) mounted on an LNG carrier that carries LNG.

A spherical tank as shown in FIGS. 1 and 2 of Patent Document 1 is a pressure vessel independent of a hull, and is supported on the hull by a skirt extending in a vertical direction from a foundation deck of the hull. The tank mounted on the LNG carrier has pressure resistance and heat resistance for storing cryogenic LNG in a high pressure state regardless of the type of tank, but there are advantages and disadvantages depending on the tank type. Different. For example, the spherical tank has a true spherical shape compared to other types of tanks, so it can be designed without the need for reinforcement on the inside, eliminating the stress concentration that is the source of cracks. There are advantages such as being able to.

International Publication No. 2009/084136

By the way, in recent years, there is a desire to increase the amount of liquefied gas loaded on a hull of the same size. Since spherical tanks have poor space utilization efficiency with respect to the capacity of the hold, in order to meet this demand, instead of using spherical tanks, a new tank that increases the liquefied gas loading capacity while maintaining the size of the hull (especially the width of the ship). A tank with a simple shape is desired. However, it is difficult to design a tank that enjoys the advantages of a spherical tank.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a marine liquefied gas tank and a liquefied gas carrier equipped with the marine liquefied gas tank that can increase the load of liquefied gas as compared with a spherical tank, and can be easily designed to enjoy the advantages of the spherical tank. .

In order to solve the above problems, a marine liquefied gas tank according to the present invention is a marine liquefied gas tank that is a symmetric pressure vessel around a vertical central axis, and has an upper tank body having a lower end that opens downward. A vertical tank shape passing through the central axis of one tank body of the upper tank body and the lower tank body. It matches the trajectory represented by (1).
| X / r ₁ | ^m + | y / r ₂ | ^m = 1 (1)
Here, r ₁ is the radius of the upper end or the lower end of the one tank body, r ₂ is the height of the one tank body, and m is a constant that satisfies 2 <m <3.

According to the above configuration, since the value of m in Formula (1) is set to be larger than 2, one tank body has a shape bulging obliquely upward or downward from the tank center. As a result, the tank capacity can be increased compared to a true spherical tank. If the value of m in the formula (1) becomes too large, the tank shape on the one side of the tank body becomes close to a cylindrical shape, and as a result, aggregates or the like that reinforce flat portions are required. However, in the above configuration, since the value of m in the formula (1) is set to be smaller than 3, a tank structure that can withstand the pressure of the liquefied gas can be realized without a reinforcing material or with a small reinforcing material. In addition, since the curvature of the trajectory represented by the formula (1) is continuous, the design that enjoys the advantages of the spherical tank can be easily performed.

In the marine liquefied gas tank, a vertical cross-sectional shape passing through the central axis of the other tank body of the upper tank body and the lower tank body may coincide with a locus represented by the following expression (2). .
| X / r ₁ | ⁿ + | y / r ₃ | ⁿ = 1 (2)
Here, r ₃ is the height of the other tank body, and n is a constant that satisfies 2 <n <3. According to this configuration, since the value of n in the formula (2) is set to be larger than 2, the other tank body has a shape bulging obliquely upward or downward from the tank center. Thereby, the tank capacity can be further increased. If the value of n in Equation (2) becomes too large, the tank shape on the other tank side becomes close to a cylindrical shape, and as a result, aggregates and the like that reinforce flat portions are required. However, since the value of n in Equation (2) is set to be smaller than 3, a tank structure that can withstand the pressure of the liquefied gas can be realized with no reinforcing material or with few reinforcing materials. Further, since the curvature of the trajectory represented by Expression (2) is continuous, the design that enjoys the advantages of the spherical tank can be easily performed.

R ₁ , r ₂ and r ₃ in Formula (1) and Formula (2) may satisfy r ₁ = r ₂ = r ₃ . In this case, the radius r ₁ of the opening of the upper tank body and the lower tank bodies, the height r ₂ of the lower tank bodies, since the height r ₃ of the upper tank body have the same length, the upper tank body And if there is almost no height of the connection part between the lower tank body, the width and height are almost the same as those of the conventional spherical tank. For this reason, the hull can be designed in the same manner as a conventional spherical tank.

In the case where r ₁ = r ₂ = r ₃ , m in formula (1) and n in formula (2) may satisfy m = n. In this case, since an upper tank body and a lower tank body can be made into the same shape, manufacture of a marine liquefied gas tank becomes easy.

R ₁ and r _{2 in} the formula (1) may satisfy 0.9 ≦ r ₂ / r ₁ ≦ 1.1. In this case, since the change in the curvature of the locus of equation (1) does not become extremely large, a design that further enjoys the advantages of the spherical tank becomes possible.

The marine vessel liquefied gas tank may include a vertically extending cylindrical body connecting the upper tank body and the lower tank body between the upper tank body and the lower tank body. According to this configuration, the height of the cylindrical body is increased and the liquefied gas loading capacity of the liquefied gas tank is increased within the allowable range with respect to the visibility from the bridge and the position of the center of gravity of the liquefied gas transport ship equipped with this marine liquefied gas tank. Can be increased.

According to the present invention, it is possible to provide a marine liquefied gas tank and a liquefied gas transport ship including the marine liquefied gas tank that can increase the load of liquefied gas as compared with the spherical tank and can easily enjoy the advantages of the spherical tank.

It is a side view of the liquefied gas carrier ship concerning the embodiment of the present invention. It is a top view of the liquefied gas carrier ship concerning the embodiment of the present invention. It is sectional drawing of the liquefied gas carrier ship shown in FIG. It is a figure which shows the modification of a marine liquefied gas tank.

Hereinafter, a marine liquefied gas tank according to an embodiment of the present invention and a liquefied gas carrier ship equipped with the marine liquefied gas tank will be described with reference to the drawings.

1 and 2 are a side view and a top view of a liquefied gas carrier ship 1A according to an embodiment of the present invention. The liquefied gas conveyed by the liquefied gas carrier 1A is, for example, LNG or liquid hydrogen. The liquefied gas carrier 1 </ b> A of this embodiment includes a plurality (four in this example) of marine liquefied gas tanks (hereinafter simply referred to as “tanks”) 10 in the direction of the length of the hull 20. Further, the liquefied gas carrier 1A of this embodiment is provided with a bridge 21 at a rear portion (left side in FIG. 1), which is a place for maneuvering during voyage. As shown in FIG. 1, the upper portion of the tank 10 projects upward from the upper deck 22 of the hull 20.

FIG. 3 is a cross-sectional view showing a tank 10 mounted on the liquefied gas carrier 1A and a structure for supporting it. A pair of longitudinal partition walls 25 extending in the ship length direction along the ship side skin 24 on both sides in the ship width direction of the hull 20 are provided inward from the pair of ship side skins 24 by a predetermined distance. Are disposed between the vertical partition walls 25.

A foundation deck 26 that supports the tank 10 via a skirt 27 is provided around the tank 10. The foundation deck 26 is provided at a predetermined height position below the upper deck 22 in the hull 20, and the lower end portion of the longitudinal partition wall 25 is connected to the upper surface of the foundation deck 26. The foundation deck 26 is provided so as to connect the ship side outer plates 24 to each other in the ship width direction. The skirt 27 is cylindrical, and the lower end of the skirt 27 is connected to the upper surface of the foundation deck 26, and the upper end of the skirt 27 is connected to the outer peripheral surface of the tank 10. A circular opening having substantially the same size as the diameter of the skirt 27 is provided at a position where the tank 10 is provided in the foundation deck 26.

Further, below the tank 10, an inner bottom plate 28 extending in the ship length direction along the ship bottom outer plate 23 is provided above the ship bottom outer plate 23 by a predetermined distance. A pair of bilge hopper plates 29 are provided between both ends of the inner bottom plate 28 in the ship width direction and the foundation deck 26. The bilge hopper plate 29 is also provided so as to extend in the captain direction. The bilge hopper plate 29 is inclined from both ends of the inner bottom plate 28 toward the outside in the ship width direction.

Next, the tank 10 of this embodiment will be described. The tank 10 is a pressure vessel symmetric about the vertical center axis C. The tank 10 includes a lower tank body 12 that forms a lower portion of the tank 10 and opens upward, and an upper tank body 13 that forms an upper portion of the tank 10 and opens downward. In this embodiment, the tank 10 has a lower tank body 12 and an upper tank body 13 directly connected. The outer surfaces of the lower tank body 12 and the upper tank body 13 are covered with a heat insulating material (not shown).

The lower tank body 12 is bowl-shaped and has an annular upper end portion 12a. The horizontal cross-sectional shape of the lower tank body 12 is annular, and the vertical cross-sectional shape of the lower tank body 12 passing through the central axis C matches the locus represented by the following formula (1).
| X / r ₁ | ^m + | y / r ₂ | ^m = 1 (1)
In the formula (1), _{r 1} is the radius of the upper end portion 12a of the lower tank body 12, _{r 2} is the height of the lower tank body 12, the value of m is 2.5, for example.

More specifically, the vertical axis is positive and the central axis C is set as the y axis, and the straight line on the horizontal plane passing through the upper end portion 12a of the lower tank body 12 and orthogonal to the central axis C is the x axis. , The vertical cross-sectional shape of the lower tank body 12 passing through the central axis C matches the locus represented by the range of y ≦ 0 in the above equation (1).

The value of m in Equation (1) is not limited to 2.5, and any value may be used as long as 2 <m <3. Since the value of m is larger than 2, the vertical cross-sectional shape of the lower tank body 12 is a shape bulging obliquely downward from the center of the tank 10.

The upper tank body 13 has an inverted bowl shape and has an annular lower end portion 13a. The horizontal cross-sectional shape of the upper tank body 13 is annular, and the vertical cross-sectional shape of the upper tank body 13 passing through the central axis C matches the locus represented by the following formula (2).
| X / r ₁ | ⁿ + | y / r ₃ | ⁿ = 1 (2)
In the formula (2), _{r 1} is the radius of the lower end 13a of the upper tank 13, _{r 3} is the height of the upper tank 13, the value of n is 2.5, for example.

More specifically, the vertical axis is positive and the central axis C is set to the y-axis, and the straight line on the horizontal plane passing through the lower end portion 13a of the upper tank body 13 and perpendicular to the central axis C is the x-axis. When set, the vertical cross-sectional shape of the upper tank body 13 passing through the central axis C matches the locus represented by the range of y ≧ 0 in the above equation (2).

The value of n in Formula (2) is not limited to 2.5, and any value may be used as long as 2 <n <3. Since the value of n is larger than 2, the vertical cross-sectional shape of the upper tank body 13 is a shape bulging obliquely upward from the center of the tank 10. Further, the radius r ₁ of the lower end portion 13 a of the upper tank body 13 is the same value as the radius r ₁ of the upper end portion 12 a of the lower tank body 12.

In this embodiment, same as the radius r ₁ of the respective openings of the lower tank 12 and the upper tank 13, the height r ₂ of the lower tank body 12, the height r ₃ of the upper tank 13 Length. That is, r ₁ , r ₂ and r ₃ in the formulas (1) and (2) satisfy r ₁ = r ₂ = r ₃ .

The tank cover 31 is supported by the upper deck 22. The tank cover 31 is arranged outside the tank 10 by a predetermined distance from the upper tank body 13 and has the same shape as the upper tank body 13. The tank cover 31 may have a shape different from that of the upper tank body 13.

As described above, the vertical cross-sectional shape of the lower tank body 12 passing through the central axis C of the tank 10 matches the trajectory represented by the above equation (1). As can be seen from the comparison with the conventional spherical tank 40 shown by the one-dot chain line in FIG. 3, the value of m in the formula (1) is larger than 2, so the tank 10 The shape swells obliquely downward from the center. Thereby, the tank capacity can be increased by effectively utilizing the space between the tank 10 and the hull 20 (for example, the inner bottom plate 28 and the bilge hopper plate 29).

Also, if the value of m in the formula (1) becomes too large, the shape of the lower part of the tank 10 becomes close to a cylindrical shape, and as a result, an aggregate or the like that reinforces a flat portion is required. However, since the value of m in Equation (1) is set to be smaller than 3, a tank structure that can withstand the pressure of the liquefied gas can be realized with no reinforcing material or with few reinforcing materials. In addition, since the curvature of the trajectory represented by the formula (1) is continuous, a design that takes advantage of the spherical tank that the reinforcing material is unnecessary or reduced can be easily performed. In addition to the above-mentioned advantages, structural analysis can be facilitated, a highly reliable design can be achieved, and the outer surface can be made smaller than that of a rectangular tank, etc., and heat intrusion into the tank 10 can be reduced. The design which also enjoyed the advantages such as being able to be performed can be easily performed.

In the tank 10, the vertical cross-sectional shape of the upper tank body 13 passing through the central axis C matches the locus represented by the expression (2). As can be seen from the comparison with the conventional spherical tank 40 shown by the one-dot chain line in FIG. 3, the value of n in the formula (2) is larger than 2, so that the tank 10 The shape swells obliquely upward from the center. As a result, the tank capacity can be increased within the allowable range with respect to the visibility from the bridge 21 and the position of the center of gravity of the liquefied gas carrier 1A.

In addition, if the value of n in the formula (2) becomes too large, the shape of the upper part of the tank 10 becomes close to a cylindrical shape, and as a result, aggregates or the like that reinforce flat portions are required. However, since the value of n in Equation (2) is set to be smaller than 3, a tank structure that can withstand the pressure of the liquefied gas can be realized with no reinforcing material or with few reinforcing materials. In addition, since the curvature of the trajectory represented by Expression (2) is continuous, a design that can enjoy the advantage of the spherical tank that the reinforcing material is unnecessary or reduced can be easily performed. In addition to the above-mentioned advantages, structural analysis can be facilitated, a highly reliable design can be achieved, and the outer surface can be made smaller than that of a rectangular tank, etc., and heat intrusion into the tank 10 can be reduced. The design which also enjoyed the advantages such as being able to be performed can be easily performed.

In this embodiment, the radius r ₁ of the respective openings of the lower tank 12 and the upper tank 13, the height r ₂ of the lower tank body 12, the height r ₃ and the same of the upper tank 13 Length (ie, r ₁ = r ₂ = r ₃ ). Therefore, the width and height are almost the same as those of the conventional spherical tank. For this reason, the hull 20 can be designed in the same manner as a conventional spherical tank.

Further, in this embodiment, the value of m in the formula (1) and the value of n in the formula (2) are both 2.5, which is the same value, so the lower tank body 12 and the upper tank body 13 are the same. It becomes a shape and manufacture of the tank 10 becomes easy.

FIG. 4 is a view showing a tank 50 which is a modification of the tank 10. As shown in FIG. 4, the tank 50 as a modified example is a cylindrical body extending in the vertical direction connecting the upper tank body 13 and the lower tank body 12 between the upper tank body 13 and the lower tank body 12. 51.

As shown in FIG. 4, the upper end portion 12a of the lower tank body 12 and the lower end portion 13a of the upper tank body 13 are arranged on different horizontal planes. That is, the x-axis of each of the expressions (1) and (2) is also located on different horizontal planes. More specifically, the vertical axis is positive and the central axis C is set as the y axis, and the straight line on the horizontal plane passing through the upper end portion 12a of the lower tank body 12 and orthogonal to the central axis C is the x axis. , The vertical cross-sectional shape of the lower tank body 12 passing through the central axis C matches the locus represented by the range of y ≦ 0 in the above equation (1). Further, when the vertical axis is positive and the central axis C is set as the y axis, and a straight line passing through the lower end portion 13a of the upper tank body 13 and perpendicular to the central axis C is set as the x axis, The vertical cross-sectional shape of the upper tank body 13 passing through the central axis C matches the locus represented by the range of y ≧ 0 in the above equation (2).

According to the configuration of the tank 50, the liquefied gas load capacity of the tank 50 can be increased as the height of the cylindrical body 51 is increased. However, when the height of the cylindrical body 51 is increased, the visibility from the bridge 21 may be deteriorated and the stability of the liquefied gas carrier ship 1A may be deteriorated due to the center of gravity of the tank 50 moving upward. For this reason, the height of the cylindrical body 51 is set within a range in which visibility from the bridge 21 can be sufficiently secured and allowed as the center of gravity position of the liquefied gas carrier ship 1A.

The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

For example, in the above embodiment, the radius r ₁ of the respective openings of the lower tank 12 and the upper tank 13, the height r ₂ of the lower tank body 12, the height r ₃ of the upper tank 13 Have the same length, but may be of different lengths. In addition, the ratio of r ₁ and r _{2 in} the formula (1) preferably satisfies 0.9 ≦ r ₂ / r ₁ ≦ 1.1. By setting the ratio in this way, the change in the curvature of the locus of the formula (1) does not become extremely large, so that the lower tank body 12 can be designed to further enjoy the advantages of the spherical tank. Similarly, the ratio of r ₁ and r ₃ in the formula (2) preferably satisfies 0.9 ≦ r ₃ / r ₁ ≦ 1.1. By setting the ratio in this way, the formula (2) Therefore, the upper tank body 13 can be designed to further enjoy the advantages of the spherical tank.

In the above embodiment, the value of m in the formula (1) and the value of n in the formula (2) are the same value, but may be different values. As described above, m in equation (1) may be any value as long as it is a constant satisfying 2 <m <3. For example, m in equation (1) is the same as that of lower tank body 12. The distance is set so that the hull 20 (for example, the inner bottom plate 28 and the bilge hopper plate 29) does not come into contact with the hull 20. In the above embodiment, n in the formula (2) may be any value as long as it is a constant satisfying 2 <n <3. For example, n in the formula (2) is the stability of the liquefied gas carrier 1A. Therefore, the position of the center of gravity of the liquefied gas carrier ship 1A when the tank 10 is fully loaded is set so that the property is maintained.

Moreover, in the said embodiment, only the vertical cross-sectional shape which passes along the central axis C of one tank body of the upper tank body 13 and the lower tank body 12 of the

tanks

10 and 50 is Formula (1) (however, 2 <m < You may be comprised so that it may correspond to the locus | trajectory represented by 3). In this case, for example, the other tank body of the upper tank body 13 and the lower tank body 12 may have the same shape as a conventional spherical tank.

1A liquefied

gas carrier

10,50 radius r ₂ of the upper end of the marine liquefied gas tank 12 below the tank body 12a lower tank body upper portion 13 the upper tank body 13a the upper tank body lower portion 51 cylinder r ₁ bottom tank of the Lower tank body height r ₃ Upper tank body height

Claims

A marine liquefied gas tank that is a symmetric pressure vessel around a vertical central axis,
An upper tank body having a lower end that opens downward;
A lower tank body having an upper end that opens upward,
A marine liquefied gas tank in which a vertical cross-sectional shape passing through the central axis of one tank body of the upper tank body and the lower tank body matches a locus represented by the following formula (1).
| X / r 1 | m + | y / r 2 | m = 1 (1)
Here, r 1 is the radius of the upper end or the lower end of the one tank body, r 2 is the height of the one tank body, and m is a constant that satisfies 2 <m <3.
The ship liquefaction according to claim 1, wherein a vertical cross-sectional shape passing through the central axis of the other tank body of the upper tank body and the lower tank body matches a locus represented by the following formula (2). Gas tank.
| X / r 1 | n + | y / r 3 | n = 1 (2)
Here, r 3 is the height of the other tank body, and n is a constant that satisfies 2 <n <3.
R 1, r 2 and r 3 of the formula (1) and (2) satisfies r 1 = r 2 = r 3, marine liquefied gas tank according to claim 2.
The marine liquefied gas tank according to claim 3, wherein m in the formula (1) and n in the formula (2) satisfy m = n.
The marine liquefied gas tank according to any one of claims 1 to 4, wherein r 1 and r 2 in the formula (1) satisfy 0.9 ≦ r 2 / r 1 ≦ 1.1.
The cylindrical body extending in a vertical direction connecting the upper tank body and the lower tank body is included between the upper tank body and the lower tank body. Marine liquefied gas tank.
A liquefied gas carrier ship comprising the marine liquefied gas tank according to any one of claims 1 to 6.