Cold temperature liquid transportation vessel

Abstract

To provide a low temperature liquid transportation vessel with less labor for construction compared to an LPG vessel or an LNG vessel and also improving economical efficiency by adopting a composition of integral with hull type tank method in a low temperature liquid transportation vessel storing liquefied ammonia or low temperature liquid of a substance liquefied at cooling temperature equivalent to liquefied ammonia in a tank.SOLUTION: A tank 3 is composed by one or more tank structures 31 composed by a plurality of partition walls built mainly using flat plate state steel plate for low temperature use inside an inner shell 12 and an upper deck 14. The tank structure 31 is covered by heatproof material 7. A coupling structure 4 coupling the inner shell 12 and the upper deck 14 with the tank structure 31 is composed by using stainless steel plate. One or more re-liquefaction apparatus 8 for liquefying gas generated in one or more tank structures are provided for the tank.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cryogenic liquid carrier having a tank containing liquefied ammonia or a cryogenic liquid that is a substance that liquefies at the same cooling temperature as liquefied ammonia, and a method for manufacturing the same. [Background technology]

[0002] Liquefied gas carriers (low-temperature liquid carriers) are ships that liquefy and transport LNG, which is a gas at room temperature. There are ships that liquefy the gas at room temperature by applying high pressure or by using cryogenic refrigeration at relatively high pressure (Type C independent tank ships), and ships that liquefy the gas at cryogenic temperatures and transport it at normal pressure (Type A / B independent tank ships, membrane ships, integral tank ships). The tanks of Type C independent tank ships are high-pressure tanks (pressure vessels), and if they are made large, the tank shell (outer skin or hull) becomes extremely thick, making it uneconomical, so small tanks are the norm. To make it economical to make them large and transport large quantities, it is appropriate to use a type that liquefies the gas at cryogenic temperatures and liquefies it at normal pressure. The temperatures required for liquefaction in this case are -163°C for LNG, -50°C for LPG, and -30°C for ammonia.

[0003] For this reason, LPG ships that transport liquefied petroleum gas (LPG) have been used to transport ammonia as well. This is because LPG ships (independent tank type) transport LPG at -50°C, so it is relatively easy to use them to transport liquefied ammonia at -30°C.

[0004] Japanese Utility Model Publication No. 46-10354 (Patent Document 1) discloses a structure in which a tank is supported by a hull of a low-temperature liquefied gas (LNG) carrier using a sliding support material that has two functions of sliding support and heat insulation. This sliding support material does not fasten the tank to the hull, but is sandwiched between the shrinking tank and the unshrinking hull to allow sliding when the tank thermally shrinks due to the low-temperature liquid inside. In other words, the hull is not pulled by the tank, that is, no stress due to the shrinkage of the tank occurs in the hull. The heat insulating material is a material with extremely low thermal conductivity (less than 1 / 100 of steel), which suppresses heat inflow and suppresses gasification due to the rise in temperature of the liquefied gas in the tank, making it possible to transport it in liquid form. This structure is a requirement of the independent tank system common to current LPG ships, and it is a common and essential item to sandwich a support material that is both a sliding support material and a heat insulating material without fastening the tank to the hull. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Jpn. Jpn. Published No. 10354-1971 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, currently, it is difficult to transport large amounts of liquefied ammonia (tens of thousands of m3 in liquefied form). 3 The mainstream vessels for transporting ammonia to these temperatures (above 100℃) are LPG carriers operated as ammonia carriers. However, the temperature of liquefied ammonia is -30℃, which is higher than LNG (-163℃) and LPG (-50℃), and the impact of thermal stress on the surrounding structures is relatively minor. Therefore, rather than using expensive vessels such as LNG and LPG carriers that require a great deal of effort to build due to the use of sliding support materials, it is more economical to use cheaper vessels with simpler structures that can handle higher temperatures.

[0007] The object of the present invention is to provide a cryogenic liquid carrier that stores liquefied ammonia or a cryogenic liquid that is a substance that liquefies at the same cooling temperature as liquefied ammonia in its tank, and that employs a tank type configuration integrated with the hull, thereby requiring less construction effort than LPG carriers or LNG carriers and improving economic efficiency, and a method for manufacturing the same. [Means for solving the problem]

[0008] The present invention is directed to a cryogenic liquid carrier equipped with a double hull having an outer hull and an inner hull, an upper deck, and a tank arranged inside the double hull and the upper deck, in which liquefied ammonia or a cryogenic liquid of a substance that liquefies at a cooling temperature equivalent to that of liquefied ammonia is stored. In the present invention, the tank is composed of one or more tank structures composed of a plurality of bulkheads constructed mainly using flat low-temperature steel plates on the inside of the inner hull and the upper deck. The one or more tank structures are covered with heat insulating material. A connecting structure that connects the inner hull and the upper deck to the tank structure is constructed using stainless steel plates. The tank is provided with one or more re-liquefaction devices that liquefy gas generated in the one or more tank structures.

[0009] In the present invention, when the tank is made into a tank structure composed of a plurality of bulkheads constructed mainly using flat low-temperature steel plates on the inside of the inner hull and upper deck, the tank structure can be manufactured together with the double hull and upper deck during the hull manufacturing process, so that the hull and tank are easily manufactured and the structure is very simple, mainly consisting of flat plates, and the construction work is greatly reduced. As a result, not only can the price of the hull and tank be reduced, but the hull and tank can be manufactured in a short period of time. In the case of an LPG ship, the direct heat intrusion path is only the insulating resin that is the tank support material, so that extremely low temperatures can be maintained. However, when the double hull, upper deck, and tank structure are connected via a connecting structure as in the present invention, the tank and the hull are directly connected by the metal connecting structure. This causes a problem of large heat inflow from the outside. However, in the present invention, the tank structure is covered with a heat-insulating material, and the main or entire connecting structure that connects the inner hull and upper deck to the tank structure is made of stainless steel plates with low thermal conductivity to suppress heat intrusion. A heat transfer analysis was conducted on an integrated tank ship constructed in this way, and it was confirmed that the heat balance can be maintained (liquefied ammonia can be transported in liquid form) even during voyages under high temperature conditions by using a re-liquefaction device in combination. A stress analysis of the prototype hull also confirmed that the structural strength is sufficient to withstand the thermal stresses that occur.

[0010] As a result, according to the present invention, a cryogenic liquid carrier can be provided that stores liquefied ammonia or a cryogenic liquid that is a substance that liquefies at the same cooling temperature as liquefied ammonia in a tank, and by adopting a tank type configuration that is integrated with the hull, it is possible to provide a cryogenic liquid carrier that requires less construction effort than LPG carriers or LNG carriers and can improve cost efficiency.

[0011] The tank structure includes an upper bulkhead and a lower bulkhead facing the upper bulkhead, which are spaced apart in the vertical direction, a pair of transverse bulkheads spaced apart in the longitudinal direction, and a pair of transverse bulkheads spaced apart in the transverse direction perpendicular to the longitudinal direction. A tank structure of this type is a combination of a simple triple hull structure mainly composed of flat plates, and the hull and the tank are assembled together, which reduces the labor required for construction.

[0012] The tank structure may also include an upper bulkhead spaced apart in the vertical direction, a lower bulkhead shorter in the transverse direction perpendicular to the longitudinal direction than the upper bulkhead, a pair of transverse bulkheads spaced apart in the longitudinal direction, and a pair of longitudinal bulkheads spaced apart in the transverse direction perpendicular to the longitudinal direction, and the pair of longitudinal bulkheads may include a first bulkhead portion extending in the vertical direction and a second bulkhead portion inclined to connect the first bulkhead portion and the lower bulkhead. A tank structure of this structure may have a simple triple-hull structure mainly composed of flat plates, but by including an inclined second bulkhead portion in the pair of longitudinal bulkheads, the strength of the tank structure is increased. Of course, the pair of longitudinal bulkheads may be composed of only the first bulkhead portion without including the inclined second bulkhead portion.

[0013] The upper bulkhead, the lower bulkhead, the pair of transverse bulkheads and the pair of longitudinal bulkheads may each be made of E-class steel, which can ensure the required toughness.

[0014] The connecting structure is preferably a structure including a plurality of transformers and a plurality of girders. The plurality of transformers have a plate-like portion extending in the ship's width direction connecting the upper bulkhead and the upper deck, a plate-like portion extending in the ship's width direction connecting the lower bulkhead and the inner hull, and a pair of plate-like portions extending in the vertical direction connecting a pair of longitudinal bulkheads and the inner hull, and are configured to surround the periphery of the tank as viewed from the ship's length direction, and are arranged at intervals in the ship's length direction. The plurality of girders also include one or more first girders extending in the ship's length direction connecting the upper bulkhead and the upper deck, one or more second girders extending in the ship's length direction connecting the lower bulkhead and the inner hull, and a pair of one or more third girders extending in the ship's length direction connecting a pair of longitudinal bulkheads and the inner hull. The one or more first girders, the one or more second girders, and a pair of one or more third girders are arranged at intervals in the circumferential direction of the tank when viewed from the longitudinal direction of the ship and are perpendicular to the multiple transformers. By configuring the connecting structure in this way, the thermal conductivity of the connecting structure can be reduced to the maximum extent possible, and the tank can be fixed.

[0015] It is preferable that at least a part of the transformers and the first to third girders has a through hole for workers to pass through. By forming such a through hole, the moving distance of the workers when installing the heat insulating material can be shortened, and the work efficiency can be improved.

[0016] It is preferable that a reinforcing bulkhead be provided in the center of the tank structure, which is connected to at least the upper bulkhead and the lower bulkhead, extends in the longitudinal direction of the ship, and divides the tank interior. By providing the reinforcing bulkhead, the mechanical strength of the tank structure can be maintained even when the tank structure is enlarged.

[0017] A plurality of stiffeners extending in the longitudinal direction and / or a plurality of stiffeners extending in the transverse direction and perpendicular direction may be welded to the outer surfaces of at least the upper and lower bulkheads, the pair of longitudinal bulkheads, and the pair of transverse bulkheads of the tank structure. By providing the stiffeners, the mechanical strength of each wall constituting the tank structure can be increased.

[0018] When a tank is made up of multiple tank structures spaced apart along the length of the ship, construction and maintenance work can be facilitated if the space between two adjacent tank structures is large enough for workers to enter. [Brief description of the drawings]

[0019] [Figure 1] 1A and 1B are a schematic plan view and a schematic side view conceptually showing the configuration of a cryogenic liquid carrier according to an embodiment of the present invention. [Diagram 2] 1 is a schematic cross-sectional view of a portion including a tank of an example of an embodiment of a cryogenic liquid carrier of the present invention, viewed from one side in the longitudinal direction of the ship. FIG. [Diagram 3] FIG. 2 is a schematic perspective view used to explain the configuration of one tank structure in region III shown in FIG. [Figure 4] FIG. 2 is a schematic perspective view used to explain the configuration of two tank structure portions in region IV shown in FIG. [Diagram 5] FIG. 5 is a detailed view showing a specific configuration including stiffeners when the configuration of FIGS. 3 and 4 is actually manufactured. [Figure 6] FIG. 2 is a diagram showing the arrangement of stiffeners. [Figure 7] FIG. 11 is a diagram for explaining a configuration of a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Figs. 1(A) and 1(B) are a schematic plan view and a schematic side view conceptually showing the configuration of a cryogenic liquid carrier 1 according to an embodiment of the present invention. As shown in Figs. 1(A) and 1(B), the cryogenic liquid carrier 1 according to this embodiment includes a double hull 13 having an outer hull 11 and an inner hull 12, an upper deck 14, and four tank structures 31 constituting a tank 3 arranged inside the double hull 13 and the upper deck 14. Fig. 2 is a schematic cross-sectional view of a portion including a tank 3 of a cryogenic liquid carrier 1 according to an embodiment of the present invention, as viewed from one side in the longitudinal direction L. Fig. 3 is a schematic perspective view used to explain the configuration of one tank structure 31 in region III shown in Fig. 1(A). Note that the transverse bulkhead on the stern side is not shown in Fig. 3. Fig. 4 is a schematic perspective view used to explain the configuration of two tank structures 31 in region IV shown in Fig. 1(A).

[0021] The cryogenic liquid carrier of this embodiment includes a double hull 13 having an outer hull 11 and an inner hull 12, an upper deck 14, and a tank 3 arranged inside the double hull 13 and the upper deck 14. The tank 3, which is made up of four tank structures 31, contains liquefied ammonia or a cryogenic liquid that is a substance that liquefies at a cooling temperature equivalent to that of liquefied ammonia. In FIG. 3, the outer hull 11, the inner hull 12, and the upper deck 14 are drawn as transparent for ease of understanding. Also, a filling port used when filling the tank 3 with the cryogenic liquid is not shown.

[0022] As shown in Figures 1(A) and (B), the four tank structures 31 constituting the tank 3 are arranged side by side in the ship's longitudinal direction L. The length of each tank structure 31 in the ship's longitudinal direction is several tens of meters. The four tank structures 31 constituting the tank 3 are each composed of a plurality of bulkheads constructed mainly using flat low-temperature steel plates on the inside of the inner hull 12 and upper deck 14 of the ship. In Figure 4, the two opposing transverse bulkheads 34 of the two tank structures 31 are depicted as transparent.

[0023] The tank structure 31 used in this embodiment includes an upper bulkhead 32 and a lower bulkhead 33 that are spaced apart in the vertical direction and have a shorter length in the transverse direction W perpendicular to the longitudinal direction L than the upper bulkhead 32, a pair of transverse bulkheads 34 that are spaced apart in the longitudinal direction L, and a pair of transverse bulkheads 35 that are spaced apart in the transverse direction W perpendicular to the longitudinal direction L. The pair of transverse bulkheads 35 includes a first bulkhead portion 35A extending in the vertical direction and a second bulkhead portion 35B that is inclined to connect the first bulkhead portion 35A and the lower bulkhead 33. Each bulkhead and bulkhead portion is joined by welding. The upper bulkhead 32, the lower bulkhead 33, the pair of transverse bulkheads 34, and the pair of transverse bulkheads 35 are each formed of E-class steel plate, low-temperature steel plate, or stainless steel plate. These steel materials can ensure the toughness required for steel materials even when exposed to low temperatures.

[0024] In this embodiment, the connecting structure 4 that connects the inner hull 12 and the upper deck 14 to the tank structure 31 is constructed using stainless steel plates. The connecting structure 4 has a structure including a plurality of transformers 5 and a plurality of girders 61 to 63 (64). Each transformer 5 has a plate-like portion 51 extending in the ship width direction that connects the upper bulkhead 32 to the upper deck 14, a plate-like portion 52 extending in the ship width direction that connects the lower bulkhead 33 to the inner hull 12, and a pair of plate-like portions 53 that connect a pair of longitudinal bulkheads 35 to the inner hull 12. Each transformer 5 is configured in a continuous ring shape so as to surround the periphery of the tank 3 when viewed from the longitudinal direction L. Each transformer 5 is arranged at intervals in the longitudinal direction L. The multiple girders include one or more first girders 61 extending in the ship's length direction L to connect the upper bulkhead 32 and the upper deck 14, one or more second girders 62 extending in the ship's length direction to connect the lower bulkhead 33 and the inner hull 12, and a third girder 63 extending in the ship's length direction L to connect a pair of ship's length bulkheads 35 and the inner hull 12. FIG. 4 illustrates an example in which a fourth girder 64 extending in the ship's length direction L to connect a pair of ship's length bulkheads 35 and the inner hull 12 is disposed above the third girder 63. In the example shown in FIG. 3, the one or more first girders 61, the one or more second girders 62, and a pair of one or more third girders 63 are arranged at intervals in the circumferential direction of the tank 3 as viewed from the ship's length direction L, and are perpendicular to the multiple transformers 5. The transformer 5 and the multiple girders 61 to 63 (64) are each made of stainless steel plate.

[0025] As shown in FIG. 4, the transverse bulkheads 34 of two adjacent tank structures 31 facing each other in the longitudinal direction are connected to each other by a plate-like portion 55 extending in the transverse direction W. The plate-like portion 55 is provided to maintain the mechanical strength of the transverse bulkhead 34, and may be provided in a plurality of rows in the height direction H. Of course, in order to further increase the strength of the transverse bulkhead 34, a plate-like portion extending in the height direction H perpendicular to the plate-like portion 55 may be provided. The plate-like portion 55 may be made of a stainless steel plate, but since it is not directly exposed to heat inflow from the outside, it may be made of a low-temperature steel plate or an E-class steel plate. The plate-like portion 55 is used as a foothold for a person to enter the space formed between the two transverse bulkheads 34 facing each other of the two tank structures 31 to inspect the outer surface of the heat insulation material.

[0026] Conventional LPG carriers are constructed by building a ship with a double hull at the bottom and single hull at the sides, and then integrating a separately manufactured independent rectangular LPG tank or dividing the LPG tank into several large pieces and installing it inside the hull. Therefore, since the tank itself is a single hull structure, it is like building another ship inside a ship, so it takes a lot of double construction work. In contrast, if a simple triple hull structure consisting mainly of flat plates is used as in this embodiment, the hull and the tank are assembled together, so the construction work is reduced.

[0027] Furthermore, when the connecting structure 4 is made of stainless steel plate as in this embodiment, the thermal conductivity of the connecting structure 4 can be reduced to the greatest possible extent, and the tank 3 can be fixed. At least a portion of the transformers 5 and the first to third girders 61 to 63 (64) may be provided with access holes for workers to pass through. By providing such access holes, the travel distance of workers when installing the heat insulating material can be shortened, and work efficiency can be improved.

[0028] 2, in this embodiment, the tank structure 31 is covered with a heat insulating material 7 such as polyurethane foam. In this embodiment, the tank structure 31 is covered with the heat insulating material 7, and the main or entire parts of the connecting structure 4 connecting the inner hull 12 and the upper deck 14 to the tank structure 31 are made of stainless steel plates with low thermal conductivity, thereby suppressing heat penetration. The tank 3 is provided with at least one re-liquefaction device 8 that liquefies gas generated in the tank structure 31.

[0029] As a result of conducting a thermal conduction analysis of an integrated tank ship configured in this manner, it was confirmed that by using the re-liquefaction device 8 in addition, heat balance can be maintained (liquefied ammonia can be transported in liquid form) even during voyages under high temperature conditions.

[0030] When the tank 3 is provided with a tank structure 31 made up of multiple bulkheads made mainly of flat low-temperature steel plates inside the inner hull 12 and upper deck 14 as in this embodiment, the tank structure 31 can be manufactured together with the double hull 13 and upper deck 14 during the hull manufacturing process, making the tank easy to manufacture and resulting in a very simple structure mainly made of flat plates, greatly reducing the labor required for construction. As a result, not only can the price of the hull and tank 3 be reduced, but the hull and tank 3 can also be manufactured in a short period of time.

[0031] 5 and 6 are detailed views showing a specific configuration including stiffeners 9, 10A, and 10B when the configuration of FIG. 3 and FIG. 4 is actually manufactured. In FIG. 5 and FIG. 6, the same members as those shown in FIG. 1 to FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted. In FIG. 5 and FIG. 6, a plurality of frames having an L-shaped cross section and extending in the longitudinal direction, which are welded to the outer surfaces of the upper bulkhead 32, the lower bulkhead 33, and the longitudinal bulkhead 35, are stiffeners 9 that prevent the bulkheads extending in the longitudinal direction from deflecting. In FIG. 5, the portion drawn by a dotted line in the center of the plate-like parts 51 to 53 that constitute the transformer 5 is stiffener 10A that prevents the plate-like parts 51 to 53 from deflecting. Furthermore, a plurality of stiffeners 10B are arranged at intervals so as to be perpendicular to the stiffeners 10A.

[0032] FIG. 7 is a diagram for explaining the configuration of the second embodiment of the present invention. In FIG. 7, the same members as those used in the configuration of the first embodiment shown in FIG. 1 to FIG. 3 are assigned the same reference numerals as those assigned to the members shown in FIG. 1 to FIG. 3, and the description thereof will be omitted. In the first embodiment shown in FIG. 2 to FIG. 6, in order to strengthen the structure of a large ship, a pair of ship-length bulkheads 35 of a tank structure 31 is composed of a first bulkhead portion 35A extending in the vertical direction and a second bulkhead portion (hopper inclined portion) 35B inclined to connect the first bulkhead portion 35A and the lower bulkhead 33. The second embodiment shown in FIG. 7 is intended for a medium-sized ship, and differs from the first embodiment in that the second bulkhead portion (hopper inclined portion) 35B inclined from the ship-length bulkhead 35 is eliminated, and the ship-length bulkhead 35 extends straight. In the case of small and medium-sized ships, the structural strength is sufficient even without the hopper portion, so by adopting the structure of the second embodiment shown in FIG. 7, the construction can be simplified and the number of construction steps can be reduced.

[0033] 2, a reinforcing bulkhead 15 may be provided in the center of the tank structure 31, connected to at least the upper bulkhead 32 and the lower bulkhead 33 to divide the inside of the tank. By providing the reinforcing bulkhead 15, the mechanical strength of the tank structure 31 can be maintained even when the tank structure 31 is enlarged. [Industrial Applicability]

[0034] According to the present invention, a cryogenic liquid carrier having a tank that stores liquefied ammonia or a cryogenic liquid that is a substance that liquefies at the same cooling temperature as liquefied ammonia can be provided, which requires less construction effort than LPG carriers or LNG carriers and is more economical by adopting a tank type configuration that is integrated with the hull. [Explanation of symbols]

[0035] 1. Cryogenic Liquid Carrier 11 Outer shell 12 Inner shell 13 Double Hull 14 Upper Deck 3. Tank 31 Tank Structure 32 Upper bulkhead 33 Lower Bulkhead 34 Transverse bulkhead 35 Vessel bulkhead 4 Connected structures 5. Transformer 61~63 Guard 7. Heat Insulation 8 Reliquefaction equipment 9,10A,10B Stiffener

Claims

1. A cryogenic liquid carrier comprising a double hull having an outer hull and an inner hull, an upper deck, and a tank disposed inside the double hull and the upper deck, the tank containing liquefied ammonia or a cryogenic liquid of a substance that liquefies at a cooling temperature equivalent to that of liquefied ammonia, The tank is composed of one or more tank structures formed by a plurality of bulkheads mainly constructed using flat low-temperature steel plates on the inside of the inner hull and the upper deck, The tank structure is covered with a heat insulating material, a connecting structure connecting the inner hull and the upper deck to the tank structure is made of stainless steel plates; A cryogenic liquid transport ship, characterized in that the tank is provided with one or more re-liquefaction devices for liquefying gas generated within the tank structure.

2. The cryogenic liquid carrier of claim 1, wherein the tank structure comprises an upper bulkhead arranged at intervals in the vertical direction and a lower bulkhead opposite the upper bulkhead, a pair of transverse bulkheads arranged at intervals in the longitudinal direction, and a pair of longitudinal bulkheads arranged at intervals in the transverse direction perpendicular to the longitudinal direction.

3. The tank structure includes an upper bulkhead arranged at intervals in the vertical direction, a lower bulkhead having a shorter length in the width direction perpendicular to the longitudinal direction than the upper bulkhead, a pair of width direction bulkheads arranged at intervals in the longitudinal direction, and a pair of length direction bulkheads arranged at intervals in the width direction perpendicular to the longitudinal direction, 2. A cryogenic liquid carrier as described in claim 1, wherein the pair of longitudinal bulkheads comprises a first bulkhead portion extending vertically and a second bulkhead portion inclined to connect the first bulkhead portion and the lower bulkhead.

4. 4. The cryogenic liquid carrier according to claim 2, wherein the upper bulkhead, the lower bulkhead, the pair of transverse bulkheads and the pair of longitudinal bulkheads are each formed of E class steel.

5. the connecting structure has a plate-like portion extending in the ship's width direction connecting the upper bulkhead and the upper deck, a plate-like portion extending in the ship's width direction connecting the lower bulkhead and the inner hull, and a pair of plate-like portions extending in the vertical direction connecting the pair of longitudinal bulkheads and the inner hull, and is configured to surround the periphery of the tank when viewed from the longitudinal direction, and a plurality of transformers arranged at intervals in the longitudinal direction; one or more first girders extending in the longitudinal direction and connecting the upper bulkhead and the upper deck, one or more second girders extending in the longitudinal direction and connecting the lower bulkhead and the inner hull, and a pair of one or more third girders extending in the longitudinal direction and connecting the pair of longitudinal bulkheads and the inner hull, 2. The cryogenic liquid carrier according to claim 1, wherein the one or more first girders, the one or more second girders, and the pair of one or more third girders are arranged at intervals in the circumferential direction of the tank when viewed from the longitudinal direction of the ship and have a structure perpendicular to the multiple transformers.

6. 6. The cryogenic liquid carrier according to claim 5, wherein a through hole for workers to pass through is formed in at least a part of the plurality of transformers and the first to third girders.

7. 2. The cryogenic liquid carrier according to claim 1, wherein a reinforcing bulkhead is provided in the central portion of the tank structure, the bulkhead being connected to at least the upper bulkhead and the lower bulkhead, extending in the longitudinal direction of the ship, and dividing the interior of the tank.

8. A cryogenic liquid carrier as described in claim 2, wherein at least the upper bulkhead and the lower bulkhead, the pair of longitudinal bulkheads and the pair of transverse bulkheads of the tank structure are welded to the outer surfaces thereof with a plurality of stiffeners extending in the longitudinal direction and / or a plurality of stiffeners extending in the transverse direction and vertically thereto.

9. The one or more tank structures are comprised of a plurality of tank structures spaced apart in the longitudinal direction of the ship, 2. The cryogenic liquid carrier according to claim 1, wherein a space between two adjacent tank structures has a size that allows an operator to enter.

Images