WO2018070239A1

WO2018070239A1 - Liquefied gas carrying vessel

Info

Publication number: WO2018070239A1
Application number: PCT/JP2017/034844
Authority: WO
Inventors: 鈴木　宏始
Original assignee: 三井造船株式会社
Priority date: 2016-10-11
Filing date: 2017-09-27
Publication date: 2018-04-19
Also published as: JP6737431B2; JP2018062196A; CN109863080B; KR20190087403A; CN109863080A

Abstract

The present invention provides a liquefied gas carrying vessel, which maximizes the capacity of a cargo tank while ensuring ballast water capacity such that the vessel has sufficient stability. This liquefied gas carrying vessel (1) has, within a cargo hold (10), a cargo tank (10a) capable of loading liquefied gas having a specific gravity in the range of 0.58-0.70, wherein: the cargo tank (10a) except for a tank dome portion (10b) is disposed below an upper deck (7); Lpp/Bm is within a range of 5.0-6.0 and Bm/dsm is within a range of 2.0-3.0, where the length over all Loa is in a range of 160-190 m, Lpp is the length between perpendiculars, Bm is the breadth molded, and dsm is the full load draft; and in the hull central cross section, Sbm/Smm is within a range of 0.10-0.25, where Sbm is the sectional area of a ballast tank (20) and Smm is the sectional area of the hull.

Description

Liquefied gas carrier

The present invention relates to a liquefied gas carrier, and more particularly, to a liquefied gas carrier having sufficient restoration performance by ensuring the maximum volume of a cargo tank and also ensuring the volume of ballast water.

Conventionally, a liquefied gas carrier is also called a gas carrier, and liquefied natural gas (LNG), liquefied petroleum gas (LPG) such as propane and butane, and ammonia are loaded in a cargo tank in a liquid state. Transported. Of these, the LNG ship has a very low temperature of about minus 163 ° C during transportation, and the ship side portion of the cargo hold with the cargo tank has a vertical side on the inner side of the ship side skin, except when a pressure tank is installed. Consists of double ship side with bulkhead. On the other hand, in the LPG ship, the temperature during transportation is about minus 50 ° C., which is higher than that of LNG, and the ship side portion of the cargo hold is constituted by a single ship side of a ship side outer plate.

Among cargo ships, this liquefied gas carrier cannot be equipped with a ballast-holding hold that allows ballast water to enter and exit from the cargo hold, unlike a bulk cargo ship. If secured large, the volume of the ballast tank is limited, and it becomes difficult to secure the degree of submersion of the stern propeller in the ballast state, and it becomes difficult to secure the draft necessary for preventing bow slamming. In particular, it is difficult to secure a ballast volume in a cargo hold of a type in which the hull has a single ship side structure, a cargo hold is provided in the main hull, and a rectangular tank is installed in the cargo hold.

On the other hand, the liquefied gas carrier has a service speed of 15 knots (kts) to 18 knots (kts) and a fluid number Fn of 0.18 to 0.23. In this Froude number Fn region, the wave resistance coefficient tends to be larger than when the Froude number Fn is less than 0.18. Therefore, if the hull is enlarged for securing the ballast tank volume, the wave-making resistance is further increased, so that it is difficult to enlarge the hull.

Furthermore, when the specific gravity of the loaded cargo is about 0.58 to 0.70 as in the LPG carrier, the weight of the loaded cargo becomes larger than that of LNG (specific gravity = 0.45 to 0.50). In that case, the hull drainage volume and drainage volume increase according to the weight of the cargo to be loaded, and the ballast tank volume relatively decreases. As a result, it becomes difficult to ensure the required draft in the ballast state. In addition, in order to keep the draft of the liquefied gas carrier ship from becoming too deep in the cargo loading state, the width will be relatively widened in this case, and in this case the wave resistance will also increase. As a result, the propulsion performance decreases.

In this connection, for example, as described in Japanese Patent Application Laid-Open No. 2011-148358, in order to suppress an increase in manufacturing cost and weight even when the cargo container is enlarged. A cargo hull carrying a liquefied gas such as LNG or LPG, a hull having a double hull structure having an inner shell and an outer shell, and a cover member having a single hull structure connected to the upper part of the hull and covering a rectangular tank There is proposed a ship in which the hull is formed at substantially the same height as the deck of the hull.

In this ship, ballast water is mounted between the inner shell and outer shell of the double hull structure and inside the double bottom, so it is necessary to increase the volume of this part, and the cargo volume below the deck is small. Therefore, in order to secure the cargo volume, the rectangular tank is expanded above the deck. For this reason, the center of gravity of the entire hull becomes high and the restoration performance is deteriorated. To prevent this, it is necessary to increase the ballast volume. The increase in the ballast volume increases as the center of gravity increases as the specific gravity of the cargo increases.

Japanese Patent Application No. 2011-148358

An object of the present invention is to provide a liquefied gas carrier that transports a liquefied gas having a relatively high specific gravity, such as liquefied propane, in a liquefied gas tank having a sufficient recovery performance by securing the maximum capacity of the cargo tank and the volume of ballast water To provide a gas carrier.

In order to achieve the above object, the liquefied gas carrier ship of the present invention is a liquefied gas carrier ship having a cargo tank in a cargo hold in which a liquefied gas having a specific gravity of 0.58 or more and 0.70 or less can be mounted. The cargo tank is arranged below the upper deck except for the tank dome, the overall length Loa is 160 m or more and 190 m or less, the length between perpendiculars is Lpp, the mold width is Bm, and the full draft is dsm. Sometimes, Lpp / Bm is 5.0 or more and 6.0 or less, Bm / dsm is 2.0 or more and 3.0 or less, and the cross-sectional area of the ballast tank is Sbm in the hull central section. When the cross-sectional area of the hull is Smm, Sbm / Smm is configured to be 0.10 or more and 0.25 or less.

According to this configuration, the volume of the cargo tank and the volume of the ballast water can be secured, the number of ports that can be entered and exited due to the total length restriction can be increased, and the draft can be made relatively small with respect to the total length, It is easy to secure the bow stern draft that meets the regulation standards for passing through the Panama Canal, and it is possible to suppress the increase in resistance of the hull and ensure propulsion performance, course stability, and stability.

A cargo tank capable of mounting a liquefied gas having a specific gravity in the range of 0.58 or more and 0.70 or less does not mean that a liquefied gas other than the specific gravity range cannot be mounted. This means that a range of liquefied gas can be installed. For example, it includes a case where liquefied gas having a specific gravity of 0.9 or more is partially loaded on several cargo tanks.

Further, in the above liquefied gas carrier ship, it is configured to have a single ship side portion, and in the center cross section of the hull, the cross-sectional area of the ballast tank below the single ship side portion is Sbm1, and more than the single ship side portion. Assuming that the cross-sectional area of the upper ballast tank is Sbm2, the following effects are obtained when the value of Sbm2 / Sbm1 is 0.4 or more and 0.7 or less.

The weight balance between the upper ballast water and the lower ballast water greatly affects the stability, but this distribution makes it easy to ensure sufficient restoration performance. In other words, the more ballast water in the lower part, that is, the larger the lower ballast tank and the smaller the upper ballast tank, the lower the center of gravity of the ship, but the upper ballast tank becomes smaller, so the upper side used as a ballast tank It becomes difficult to secure the strength of the upper side of the cargo hold due to the bottom wall structure of the tank. On the other hand, the more ballast water in the upper part, that is, the larger the upper side tank is, the easier it is to secure the strength above the cargo hold, but the center of gravity of the ship rises, making it difficult to ensure stability.

Further, in the above liquefied gas carrier ship, a front ballast section is provided between the cargo hold and the bow bulkhead, and the length Lbf in the ship length direction of the front ballast section is 2.0 of the vertical length Lpp. % Or more and 5.0% or less in range, the following effects are obtained.

When the length in the ship length direction of the front ballast section is 2.0% or more of the perpendicular length Lpp, it becomes easy to secure the ballast volume even when the total length of the ship is limited. If the total length exceeds 5.0%, it is difficult to secure the hold length of the cargo hold and the cargo volume when the total length of the ship is limited.

Furthermore, in the above liquefied gas carrier, if the residential area including the bridge is formed with five layers without the bow, the following effects are obtained.

In other words, in the case where a bow tower is provided, it is necessary to make the living area 6 layers because it is necessary to secure a line of sight in front of the bow, but since this can be avoided, the center of gravity of the entire ship is lowered. This makes it easier to ensure the required restoration performance. In addition, the omission of the bow can suppress the increase in the total tonnage, and the residential area can be lowered to five layers, so that it is easy to secure the air draft. In addition, the structural weight can be reduced by the amount of one layer in the residential area and the bow tower, and the center of gravity can be lowered.

The liquefied gas carrier of the present invention is a liquefied gas carrier that transports liquefied gas having a relatively large specific gravity such as liquefied propane, and ensures the capacity of the cargo tank and the capacity of ballast water to ensure sufficient restoration performance. Can be secured.

FIG. 1 is a side sectional view schematically showing a configuration of a liquefied gas carrier ship according to an embodiment of the present invention. FIG. 2 is a plan layout view immediately below the upper deck of the ship of FIG. FIG. 3 is a cross-sectional view of the center of the hull of the ship of FIG. 1 (in the case where there is no tank dome in the center of the hull). FIG. 4 is a cross-sectional view of the center of the hull of the ship shown in FIG. 1 (when the tank dome is in the center of the hull).

Hereinafter, a liquefied gas carrier according to an embodiment of the present invention will be described with reference to the drawings. The liquefied gas carrier 1 according to the embodiment of the present invention is a liquefied gas carrier that carries a liquefied gas having a relatively large specific gravity such as LPG (liquefied petroleum gas).

In the liquefied gas carrier 1 of the embodiment shown in FIG. 1 to FIG. 3, the bow part 2, the stern part 3, the ship bottom 4, the double plate bottom plate (cargo hold bottom plate) 5, the ship side skin plate 6 and the top A hull is formed surrounded by the deck 7. Further, a cargo tank 10a (thick line portion) in the cargo hold 10 for loading liquefied gas, a ballast tank (cross hatched portion) 20 for taking in and out ballast water, and a fuel tank (shaded hatched portion) 30 for loading fuel are provided. . In this liquefied gas carrier 1, the cargo tank 10a is disposed below the upper deck 7 except for the tank dome 10b. The tank dome 10b is a portion provided with various through portions such as pipes and manholes as shown in FIG.

The bow part 2 has a bow bulkhead 2a at the rear part, and is provided with a bow flare 2b and a bow valve 2c in the outer shape, and without the bow tower, inside the boat store 2d under the upper deck 7 And has a ballast tank 2e below it. On the other hand, in the stern part 3, an engine room 3b, a propeller 3c, and a rudder 3d are provided on the rear side of the engine room front wall 3a. Further, an upper structure 3e having a residential area 3ea including a bridge 3eaa is provided above the engine room 3b, and the upper structure 3e is also provided with a chimney 3eb.

In this liquefied gas carrier 1, the Froude number Fn at the normal speed Vs (m / s) is in the range of 0.18 or more and 0.23 or less. Here, the Froude number Fn becomes “Fn = Vs / (Lpp × g) ^1/2 ” by using the length Lpp (m) between the vertical lines on the full waterline of the ship and the gravitational acceleration g (m / s ² ). .

The liquefied gas carrier 1 can load liquefied gas having a specific gravity in the range of 0.58 or more and 0.70 or less to the cargo tank 10a up to 98% or more of the cargo volume. It is a liquefied gas carrier ship with a volume of 30,000 m ³ or more and 40,000 m ³ or less. When transporting a liquefied gas such as liquefied propane or butane such as liquefied propane or butane having a relatively high specific gravity, the volume is relatively small with respect to the weight ratio. Can be placed below.

On the other hand, in the case of liquefied natural gas (LNG) having a relatively light specific gravity, the specific gravity is 0.45 to 0.50, and a relatively large volume is required with respect to the weight ratio. For this reason, spherical tanks and cargo tanks that protrude above the upper deck are often used.

In this liquefied gas carrier 1, the total length Loa is set to 160 m or more and 190 m or less. By setting this total length Loa to 190 m or less, it becomes possible to adapt to the restrictions on the total length of ships at many ports, and preferably by setting it to 180 m or less, it is possible to increase more compatible ports. Further, by setting the total length to 160 m or more, it is possible to secure the volume of the cargo tank while keeping the hull form within the hull form capable of maintaining a speed of about 0.23 in terms of fluid number. Unless the total length is at least 160 m, it is difficult to secure a tank volume of 30,000 m ³ or more.

When it is assumed that the liquefied gas carrier 1 navigates the Panama Canal, the Panama Canal Rules stipulate the minimum bow stern draft. For example, a ship having a total length Loa of 160.02 m to 176.78 m. Stipulates that the stern draft dca is 6.71 m and the bow draft dcf is 6.10 m or more as the canal traffic state. On the other hand, by setting the total length Loa to a range of 168.40 m to 176.78 m, which is the upper half of the above range, for example, the draft dcm when passing through the canal is relatively small with respect to the total length Loa. In addition to the liquefied gas loading state, not only in the ballast state, it is easy to secure the bow draft dcf and the stern draft dca that meet this regulation standard. This draft dcm is half of the sum of the bow draft dcf and the stern draft dca. That is, dcm = (dcf + dca) / 2.

In this liquefied gas carrier 1, “(length between perpendiculars Lpp) / (mold width Bm)” is 5.0 or more and 6.0 or less. Further, “(mold width Bm) / (full load draft dsm)” is 2.0 or more and 3.0 or less, preferably 2.5 or more and 3.0 or less. By setting this “Lpp / Bm” to 5.0 or more, preferably 5.2 or more, it is possible to suppress an increase in resistance of the hull and to ensure course stability. Further, by setting “Lpp / Bm” to 6.0 or less, preferably 5.8 or less, the mold width Bm is increased with respect to the set inter-perpendicular length Lpp, so that the tank volume of the cargo hold 10 portion is increased. Can be secured relatively large, and stability can be secured.

Furthermore, by setting “Bm / dsm” to 3.0 or less, the draft is increased with respect to the set mold width Bm, thereby increasing the hull central cross-sectional area under the draft line, and the ship square coefficient Cb [= The value of (drainage volume in full draft) / (Lpp × Bm × dsm)] can be reduced. Thereby, the wave-making resistance of the ship can be suppressed and the propulsion performance can be ensured.

Further, in the hull central section (midship) in FIG. 3, the cross-sectional area of the ballast tank 20 (21 and 22) is Sbm, and the hull cross-sectional area surrounded by the ship bottom 4, the ship side outer plate 6 and the upper deck 7 is Smm. Sometimes, “Sbm / Smm” is set to 0.10 or more and 0.25 or less. If this “Sbm / Smm” is less than 0.10, it is difficult to secure the volume of the ballast tank, and if it exceeds 0.25, it is difficult to secure the volume of the cargo hold 10.

Further, the cargo tank 10a is mounted on the cargo hold 10 to have a single ship side portion, and as shown in FIG. 3, the ballast tank 21 below the single ship side portion in the center section of the hull is shown in FIG. When the cross-sectional area is Sbm1 and the cross-sectional area of the ballast tank 22 above the single ship side portion is Sbm2, the following effects are obtained when the value of Sbm2 / Sbm1 is 0.4 or more and 0.7 or less. There is.

The weight balance between the upper ballast water and the lower ballast water greatly affects the stability, but this distribution makes it easy to ensure sufficient restoration performance. In other words, the more the lower ballast water, in other words, the larger the lower ballast tank 21 and the smaller the upper ballast tank 22, the lower the center of gravity of the liquefied gas carrier 1, but the upper ballast tank 22 becomes smaller. It becomes difficult to ensure the strength of the upper side of the cargo hold 10 by the bottom wall structure of the upper side tank (top side tank) used as the upper ballast tank 22.

On the other hand, the more ballast water in the upper side, that is, the larger the upper side tank used as the upper ballast tank 22 is, the easier it is to secure the upper strength of the cargo hold 10, but the center of gravity of the liquefied gas carrier 1 is increased. It becomes difficult to secure stability.

Further, the lower ballast tank 21 wants to increase the amount of ballast water as much as possible. However, since there is a limit, the tank side width Bt1 of the lower ballast tank 21 shown in FIG. The tank side depth Dt1 is preferably 0.20 times or more and 0.35 times or less of the mold depth Dm.

Further, when ballast water is put into the upper ballast tank 22, the specific gravity of the ballast water is larger than the specific gravity of the cargo, so that the center of gravity tends to be high, and the center of the area of the cross-sectional area of the upper ballast tank 22 is at a lower position. It is preferable to provide it. Therefore, it is preferable that the tank depth Dt2 shown in FIG. 3 is not less than 0.10 times and not more than 0.35 times the mold depth Dm. Further, if the tank width Bt2 of the upper ballast tank 22 shown in FIG. 3 is increased, the width of the ballast tank (upper side tank) 22 can be secured at a position away from the center (Dm / 2) in the height direction of the hull. Although it becomes easy to ensure the strength of the upper side of the cargo hold 10, the center of gravity of the ship rises and it becomes difficult to ensure the stability. Therefore, it is preferable to set the tank width Bt2 of the upper ballast tank 22 shown in FIG. 3 to 0.15 times or more and 0.35 times or less of the mold width Bm.

A front ballast section 23 is provided between the cargo hold 10 and the bow bulkhead 2a, and the length Lbf in the ship length direction of the front ballast section 23 is not less than 2.0% of the length Lpp between vertical lines and 5.0. % Or less. By providing the front ballast section 23 having a relatively large volume at the bow side portion, trim (difference between the bow draft df and the stern draft da) can be easily adjusted.

When the length Lbf in the ship length direction of the front ballast section 23 is 2.0% or more of the length Lpp between the normals, it becomes easy to secure the ballast volume even when the total length of the ship is limited. Note that if it exceeds 5.0%, it is difficult to secure the hold length and the cargo volume of the cargo hold 10 under the condition that the total length of the ship is limited.

Furthermore, the living area 3ea including the bridge 3eaa is formed with five layers without the bow tower. As a result, when the bow tower is provided, it is necessary to make the residential area 3ea have six layers because it is necessary to secure a line of sight in front of the bow, but this can be avoided, so the center of gravity of the entire ship is lowered. Thus, it is easy to ensure the required restoration performance. Moreover, since the increase in the total tonnage can be suppressed by omitting the bow tower, and the residential area 3ea can be lowered to five layers, it is easy to secure an air draft. In addition, the structural weight of the residential area 3ea can be reduced by one layer and the bow tower, and the center of gravity can be lowered.

Even without the bow tower, the boson store 2d can be stored below the upper deck 7, the required ballast amount can be secured, and the bow draft df can be secured.

According to the liquefied gas carrier 1 configured as described above, the volume of the cargo tank 10a and the volume of ballast water can be secured, the number of ports that can be entered and exited can be increased due to the total length restriction, and the draft dcm when passing through the canal is reduced. By making it relatively small with respect to the overall length Loa, it becomes easy to secure the bow draft dcf and the stern draft dca that meet the regulation standards in the Panama Canal, and suppress the increase in the resistance of the hull, Track stability and stability can be ensured.

Therefore, in the liquefied gas carrier 1 that transports liquefied gas having a relatively high specific gravity such as liquefied propane, it is possible to secure the capacity of the cargo tank 10a to the maximum and also secure the capacity of ballast water to ensure sufficient restoration performance. it can.

1 Liquefied Gas Carrier 2 Bow 2e Ballast Tank 3e Upper Structure 3eaa Bridge 3ea Living Area 5 Double Bottom Upper Plate 6 Ship Side Outer Plate 7 Upper Deck 10 Cargo Hold

10a Cargo Tank

10b Tank Dome 11 Horizontal Bulkhead 20 Ballast Tank 21 Below Upper ballast tank 22 Upper ballast tank (upper side tank)
23 Front ballast compartment 30 Fuel tank

Claims

In a liquefied gas carrier ship having a cargo tank in a cargo hold capable of mounting a liquefied gas having a specific gravity of 0.58 or more and 0.70 or less,
The cargo tank is disposed below the upper deck except for the tank dome, and the overall length Loa is 160 m or more and 190 m or less,
Lpp / Bm is 5.0 or more and 6.0 or less, and Bm / dsm is 2.0 or more and 3.0 or less when the length between perpendiculars is Lpp, the mold width is Bm, and the full draft is dsm. And
A liquefied gas carrier ship wherein Sbm / Smm is not less than 0.10 and not more than 0.25 when the cross-sectional area of the ballast tank is Sbm and the cross-sectional area of the hull is Smm.
The ballast tank is configured to have a single ship side portion, and the cross sectional area of the ballast tank below the single ship side portion is Sbm1 and the cross sectional area of the ballast tank above the single ship side portion is Sbm2 in the center cross section of the hull. Then, the value of Sbm2 / Sbm1 is 0.4 or more and 0.7 or less, The liquefied gas carrier ship of Claim 1 characterized by the above-mentioned.
A front ballast section is provided between the cargo hold and the bow bulkhead, and the length Lbf in the ship length direction of the front ballast section is 2.0% or more and 5.0% or less of the inter-perpendicular length Lpp. The liquefied gas carrier ship according to claim 1, wherein the liquefied gas carrier ship is within the range.
The liquefied gas carrier according to any one of claims 1 to 3, wherein the liquefied gas carrier is not provided with a bow and has a five-story residential area including a bridge.