Floating structures

Abstract

To provide a floating structure that is equipped with a liquefied gas tank storing liquefied flammable gas and has high design flexibility.SOLUTION: A floating structure is equipped with a liquefied gas tank that has strength requiring no secondary barrier, a hold space that stores the liquefied gas tank, an inner passage that is adjacent to the hold space, and an inside expansion chamber that communicates with the inner passage on the side closer to the hold space than the inner passage.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a floating structure equipped with a liquefied gas tank. [Background technology]

[0002] Floating structures that float on water have limited areas for installing equipment, etc., compared to structures on land, and have less freedom in design. Furthermore, if the floating structure is equipped with a liquefied gas tank for storing liquefied flammable gas, the freedom in design is further reduced from the perspective of safety (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-120814 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure aims to provide a floating structure equipped with a liquefied gas tank for storing liquefied flammable gas, which has a high degree of freedom in design. [Means for solving the problem]

[0005] A floating structure according to one aspect of the present disclosure comprises a liquefied gas tank having strength such that a secondary barrier is not required, a hold space for accommodating the liquefied gas tank, an internal passage adjacent to the hold space, and an inner expansion chamber communicating with the internal passage on the hold space side of the internal passage. [Effects of the Invention]

[0006] According to the above configuration, it is possible to provide a floating structure that is equipped with a liquefied gas tank for storing liquefied flammable gas and that has a high degree of freedom in design. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic side view of a floating structure. [Figure 2] FIG. 2 is a schematic plan view of the floating structure. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. [Figure 4] 4 is a cross-sectional view taken along the line IV-IV in FIG. [Figure 5] 5 is a cross-sectional view taken along the line VV in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] A floating structure 100 according to an embodiment will be described below. Fig. 1 is a schematic side view of the floating structure 100, and Fig. 2 is a schematic plan view of the floating structure 100. The floating structure 100 according to this embodiment is a liquefied gas carrier that transports liquefied gas. However, the floating structure 100 may also be a floating production storage and offloading unit (FPSO), a floating LNG storage and regasification unit (FSRU), a floating production and offloading unit (FPO), a floating storage and offloading unit (FSO), or the like.

[0009] 1 and 2, a floating structure 100 according to this embodiment includes a hull 11, a liquefied gas tank 12, a hold space 13, a deck 14, an engine room 15, an aft accommodation area 16, a boatswain's storehouse 17, an internal passageway 18, a lower extension room 19, an inner extension room 20, an upper deck room 21, an independent room 22, an upper independent room 23, a branching and aggregation device 24, an opening / closing door 25, a power receiving box 26, a connection port 27, an emergency stop button 28, an electric motor 29, and a fuel cell 30. These components will be described in order below.

[0010] <Hull> The hull 11 is configured to be navigable. The concept of direction in the following explanation corresponds to the concept of direction when looking in the direction in which passengers on the floating structure 100 are sailing (to the right on the paper in Figures 1 and 2). In addition, in the following, the fore-and-aft direction of the hull 11 will be referred to as the "longitudinal direction," the left-and-right direction will be referred to as the "width direction," the front end portion will be referred to as the "bow," and the rear end portion will be referred to as the "stern."

[0011] Figure 3 is a cross-sectional view taken along the line III-III in Figure 2. As shown in Figure 3, the hull 11 includes a bottom 41 and side walls 42. The side walls 42 extend upward from both widthwise ends of the bottom 41, and the bottom 41 and side walls 42 are integrally formed. The hull 11 of this embodiment has a double structure, with the inner and outer peripheral surfaces formed of different steel plates spaced apart. In other words, the bottom 41 and side walls 42 have a double structure, with the inner and outer peripheral surfaces formed of different steel plates spaced apart. However, the hull 11 does not have to have a double structure. The hull 11 is formed entirely of steel.

[0012] <Liquefied gas tank> The liquefied gas tank 12 is a tank that stores liquefied gas. The liquefied gas tank 12 of this embodiment stores liquefied gas obtained by liquefying flammable gas. For example, the liquefied gas tank 12 stores liquefied hydrogen, liquefied natural gas (LNG), liquefied petroleum gas (LPG), etc. The floating structure 100 of this embodiment is equipped with four liquefied gas tanks 12. These liquefied gas tanks 12 are spherical or ellipsoidal and are aligned in the longitudinal direction. However, the number, shape, and arrangement of the liquefied gas tanks 12 are not limited to those described above.

[0013] Tanks that store liquefied flammable gas are classified into three types according to their strength. The first type is a tank that requires a secondary barrier that surrounds the entire tank (a complete secondary barrier). The "secondary barrier" here refers to a wall that retains liquefied gas that leaks from the tank in the event of a tank rupture. The second type is a tank that is stronger than the first type but requires a partial secondary barrier (a partial secondary barrier). The third type is a tank that is stronger than the second type and does not require a secondary barrier. Note that these first, second, and third types correspond to Types A, B, and C, respectively, defined by the International Maritime Organization (IMO). The liquefied gas tank 12 of this embodiment belongs to the third type of the three types described above. In other words, the liquefied gas tank 12 of this embodiment is a tank that is strong enough not to require a secondary barrier.

[0014] <hold space> The hold space 13 is a space that accommodates the liquefied gas tanks 12. As shown in FIG. 2, the hold space 13 is located aft of the boatswain's storehouse 17 and forward of the engine room 15. As shown in FIG. 3, the hold space 13 is located between the left and right side walls 42 and above the bottom 41 of the ship. The hold space 13 of this embodiment accommodates the liquefied gas tanks 12 with gaps between them. That is, the liquefied gas tanks 12 are not in contact with the side walls 42, bottom 41, engine room 15, and boatswain's storehouse 17 that define the hold space 13, but rather have gaps between them. The hold space 13 is divided by bulkheads 50 located between the liquefied gas tanks 12, and adjacent liquefied gas tanks 12 are not in contact with each other. The upper portions of the liquefied gas tanks 12 are covered with tank covers 40 with gaps between them.

[0015] Here, each area within the floating structure 100 is divided into a hazardous area and a non-hazardous area. Non-explosion-proof electrical equipment cannot be installed in the hazardous area, but non-explosion-proof electrical equipment can be installed in the non-hazardous area. As described above, the liquefied gas tank 12 of this embodiment is strong enough to eliminate the need for a secondary barrier. Therefore, flammable gas is unlikely to be generated within the hold space 13 that houses the liquefied gas tank 12. Therefore, even if a certain area is adjacent to the hold space 13 via a steel plate or the like, that area can be considered a non-hazardous area.

[0016] <Deck> The deck 14 is located on the hull 11 and exposed to the outside. The deck 14 is flat and, together with the tank cover 40, surrounds the liquefied gas tank 12. The deck 14 is welded to the tank cover 40. The deck 14 is not connected to the liquefied gas tank 12, and there is a gap between the deck 14 and the liquefied gas tank 12. The deck 14 is also located above an internal passage 18 and a boatswain's storehouse 17, which will be described later. In this embodiment, the liquefied gas tank 12 is strong enough to not require a secondary barrier, so flammable gas is unlikely to be generated within the hold space 13, and the deck 14 can be considered a non-hazardous area.

[0017] <Engine Room> The engine room 15 is a room that houses the main engine. The engine room 15 is located at the stern and is located below the deck 14 in the vertical direction. However, part of the engine room 15 may be located above the deck 14. The front surface of the engine room 15 is formed of steel plates, and the interior of the engine room 15 is not in communication with the hold space 13. The engine room 15 is adjacent to the hold space 13, but it does not have to be adjacent to the hold space 13. As described above, flammable gas is unlikely to be generated inside the hold space 13 in this embodiment, so even if the engine room 15 is adjacent to the hold space 13, the engine room 15 can be considered a non-hazardous area. The main engine housed in the engine room 15 is an internal combustion engine that uses boil-off gas generated in the liquefied gas tank 12, heavy oil, or the like as fuel to drive a screw propeller 43. However, the main engine may drive a steam turbine connected to the screw propeller 43 using steam generated by burning the boil-off gas. The screw propeller 43 may also be driven by a motor.

[0018] Furthermore, in this embodiment, a protruding portion 44 protrudes from the engine room 15 toward the inside of the hold space 13. The protruding portion 44 in this embodiment includes an electrical equipment room 51 and a ballast water treatment device room 52. Of these, the electrical equipment room 51 is a room that houses electrical equipment, and is located above the vertical center of the hold space 13. Furthermore, the ballast water treatment device room 52 is a room that houses a ballast water treatment device that purifies ballast water, and is located below the vertical center of the hold space 13. Note that the protruding portion 44 may be connected to the engine room 15 or may be independent.

[0019] This configuration allows the engine room 15 to be expanded by the amount of the protruding portion 44, and also allows the addition of an auxiliary machinery room or the like that is connected to or independent of the engine room 15. An emergency fire pump used to extinguish a fire in the engine room 15 may be disposed in the protruding portion 44. Even when the protruding portion 44 is independent of the engine room 15, i.e., when the protruding portion 44 and the engine room 15 are separated by an airtight wall and are different areas, an emergency fire pump used to extinguish a fire in the engine room 15 may be disposed in the protruding portion 44. In this case, an access passage extending from the deck 14 or a non-hazardous area indoors may be provided in the protruding portion 44. Furthermore, as shown in FIG. 1 , the protruding portion 44 is positioned below the center of the liquefied gas tank 12 so that at least a portion of the protruding portion 44 overlaps with the liquefied gas tank 12 in a plan view. Because the liquefied gas tank 12 of this embodiment is spherical or ellipsoidal, a large gap exists between the engine room 15 and the liquefied gas tank 12 below the center of the liquefied gas tank 12. Since the protrusion 44 is located in such a position, it is possible to effectively utilize a space that would otherwise be dead space. However, the position of the protrusion 44 is not limited to the above.

[0020] Although the protruding portion 44 in this embodiment protrudes from the engine room 15, it may also protrude from a non-dangerous area other than the engine room 15. For example, the protruding portion 44 may protrude from the boatswain store 17 and the lower extension room 19 described below toward the inside of the hold space 13. Furthermore, the number of protruding portions 44 is not limited. By having the protruding portion 44 protrude from the non-dangerous area in this way, the non-dangerous area is expanded, thereby improving the degree of freedom in design.

[0021] <Stern living area> The stern accommodation area 16 is an area where workers live or work. The stern accommodation area 16 is located in the stern section, above the engine room 15. In addition, the stern accommodation area 16 in this embodiment is located above the deck 14 and is not adjacent to the hold space 13. Therefore, the stern accommodation area 16 can be considered a non-hazardous area. Note that the floating structure 100 may be provided with a bow accommodation area in the bow section where workers live or work, in addition to or instead of the stern accommodation area 16.

[0022] <Boatswain's Warehouse> The boatswain's storehouse 17 is a storehouse for storing ship's equipment and the like. The boatswain's storehouse 17 is located in the bow section, and is located below the deck 14. However, the boatswain's storehouse 17 may also protrude above the deck 14. The aft surface of the boatswain's storehouse 17 is formed of steel plate, and the interior of the boatswain's storehouse 17 does not communicate with the hold space 13. The boatswain's storehouse 17 is adjacent to the hold space 13, but as described above, flammable gas is unlikely to be generated inside the hold space 13 in this embodiment, so the inside of the boatswain's storehouse 17 can be considered a non-hazardous area.

[0023] <Internal passage> The internal passage 18 is a passage extending longitudinally within the floating structure 100. In this embodiment, the internal passage 18 is located inside the side wall 42. However, if the hull 11 does not have a double structure, the internal passage 18 may be arranged adjacent to the side wall 42 on the hold space 13 side of the side wall 42. In addition, the internal passage 18 in this embodiment is located in the upper part of the side wall 42 and adjacent to the deck 14 below the deck 14. The internal passage 18 is surrounded by steel plates, and the interior of the internal passage 18 does not communicate with the hold space 13. Although the internal passage 18 is adjacent to the hold space 13, as described above, flammable gas is unlikely to be generated within the hold space 13 in this embodiment, so the interior of the internal passage 18 can be considered a non-hazardous area. Therefore, non-explosion-proof electrical equipment can be installed in the internal passage 18, thereby improving design freedom.

[0024] Furthermore, the aft end of the internal passage 18 is passably connected to the indoor engine room 15, and the front end is passably connected to the indoor boatswain's storehouse 17. Therefore, workers can travel between the engine room 15 and the boatswain's storehouse 17, that is, between the bow and stern, through the internal passage 18 without going outside. Note that the internal passage 18 can be considered a non-hazardous area, and therefore even if the internal passage 18 is connected to the engine room 15 and the boatswain's storehouse 17, the engine room 15 and the boatswain's storehouse 17 can remain non-hazardous areas.

[0025] In addition, the forward end portion of the internal passage 18 may extend to the forward end of the hull 11, and the aft end portion of the internal passage 18 may extend to the aft end of the hull 11. Furthermore, if the floating structure 100 has a bow structure such as a bow accommodation area located in the bow portion and at least a portion of which is located below the deck 14, the forward end portion of the internal passage 18 may be connected to a portion of the bow structure below the deck 14. Similarly, if the floating structure 100 has an aft structure such as an aft accommodation area 16 located in the aft portion and at least a portion of which is located below the deck 14, the aft end portion of the internal passage 18 may be connected to a portion of the aft structure below the deck 14.

[0026] Furthermore, watertight access doors 45 that do not allow water to enter are installed between the internal passage 18 and the engine room 15 and the boatswain's storehouse 17. Therefore, even if water enters the internal passage 18, the entered water will not reach the engine room 15 or the boatswain's storehouse 17. Furthermore, an airlock consisting of two airtight doors may be installed between the internal passage 18 and the engine room 15 or the boatswain's storehouse 17. The aft end of the internal passage 18 may be passably connected to the aft accommodation space 16 instead of the engine room 15. Similarly, the forward end of the internal passage 18 may be passably connected to the aforementioned fore accommodation space instead of the boatswain's storehouse 17. Furthermore, the internal passage 18 may be passably connected to only one of the engine room 15 and the boatswain's storehouse 17. In this embodiment, one internal passage 18 is arranged on each of the left and right sides of the floating structure 100, but the number and arrangement of the internal passages 18 are not limited.

[0027] <Lower expansion chamber> The lower extension chamber 19 is a room that communicates with the internal passage 18 below the internal passage 18. The lower extension chamber 19 and the internal passage 18 may or may not be separated by a door. The lower extension chamber 19 is located inside the side wall 42. In this embodiment, the lower extension chamber 19 is in direct contact with the internal passage 18, but may also be connected to the internal passage 18 via a passage extending in the vertical direction. The lower extension chamber 19 is surrounded by steel plates, and the interior of the lower extension chamber 19 does not communicate with the hold space 13. Although the internal passage 18 is adjacent to the hold space 13, as described above, flammable gas is unlikely to be generated within the hold space 13 in this embodiment, so the lower extension chamber 19 can also be considered a non-hazardous area. Although the floating structure 100 according to this embodiment has one lower extension chamber 19, the floating structure 100 may have multiple lower extension chambers 19.

[0028] <Inner expansion chamber> The inner extension chamber 20 is a room that communicates with the internal passage 18 on the hold space 13 side of the internal passage 18, i.e., closer to the center of the hull 11. The inner extension chamber 20 and the internal passage 18 may or may not be separated by a door. As shown in FIG. 2 , the inner extension chamber 20 is located near the space between adjacent liquefied gas tanks 12 in the longitudinal direction. Furthermore, in a plan view, the inner extension chamber 20 has a trapezoidal shape with the longer side facing the sidewall 42. However, the position and shape of the inner extension chamber 20 are not limited to those described above. The floating structure 100 according to this embodiment includes one inner extension chamber 20, but the floating structure 100 may include multiple inner extension chambers 20.

[0029] 4 is a cross-sectional view taken along the line IV-IV in FIG. 2. As shown in FIG. 4, the inner extension chamber 20 is adjacent to the deck 14 below the deck 14. The inner extension chamber 20 is also adjacent to the hold space 13. The inner extension chamber 20 is surrounded by steel plates, and the interior of the inner extension chamber 20 is not in communication with the hold space 13. Although the inner extension chamber 20 is adjacent to the hold space 13, as described above, flammable gas is unlikely to be generated within the hold space 13 in this embodiment, so the interior of the inner extension chamber 20 can be considered a non-hazardous area. In this way, by connecting the internal passage 18 and the inner extension chamber 20, the non-hazardous area continuing from the internal passage 18 can be expanded in the width direction. This expands the area in which non-explosion-proof electrical equipment can be installed, improving design freedom.

[0030] <Deck room> The above-deck room 21 is a room located on the deck 14 and is surrounded by steel plates. The above-deck room 21 is located above the internal passage 18 and the inner extension chamber 20. As shown in FIG. 2 , the above-deck room 21 is located inside the outer edge of the inner extension chamber 20 in a plan view. Furthermore, the above-deck room 21 in this embodiment is connected to the internal passage 18 and the inner extension chamber 20. However, the above-deck room 21 may be connected to either the internal passage 18 or the inner extension chamber 20, or may be independent of the internal passage 18 and the inner extension chamber 20 without being connected to either the internal passage 18 or the inner extension chamber 20.

[0031] Since the deck room 21 is located on the deck 14, which can be considered a non-hazardous area, the interior of the deck room 21 can also be considered a non-hazardous area. This allows electrical equipment that is not explosion-proof to be installed in the deck room 21, thereby improving design freedom. Note that the deck room 21 in this embodiment is located between adjacent liquefied gas tanks 12. However, the deck room 21 may also be located between the rearmost liquefied gas tank 12 and the stern, or between the forwardmost liquefied gas tank 12 and the bow.

[0032] <Independent room> The independent room 22 is a room located within the hold space 13. The independent room 22 in this embodiment does not communicate with non-hazardous areas such as the engine room 15, and is independent from these non-hazardous areas. Figure 5 is a cross-sectional view taken along the arrows VV in Figure 2. As shown in Figure 5, the independent room 22 is adjacent to the deck 14 below the deck 14. The independent room 22 is surrounded by steel plates, and the interior of the independent room 22 does not communicate with the hold space 13. Although the independent room 22 is located within the hold space 13, as described above, flammable gas is unlikely to be generated within the hold space 13 in this embodiment, and therefore the interior of the independent room 22 can be considered a non-hazardous area.

[0033] An emergency fire pump used to extinguish a fire in the engine room 15 may be disposed inside the independent room 22. In this case, an access passage extending from the deck 14 or a non-hazardous area may be provided to the independent room 22. Although the independent room 22 in this embodiment is adjacent to the deck 14, the independent room 22 does not have to be adjacent to the deck 14. For example, the independent room 22 may be located below the center of the liquefied gas tank 12 so that at least a portion of the independent room 22 overlaps with the liquefied gas tank 12 in a plan view. Because the liquefied gas tank 12 in this embodiment is spherical or ellipsoidal, there is a large gap between the engine room 15 and the liquefied gas tank 12 below the center of the liquefied gas tank 12. Therefore, if the independent room 22 is located in this position, it is possible to effectively utilize a space that would otherwise become dead space. Although the independent room 22 in this embodiment is separated from the engine room 15, the independent room 22 may be adjacent to the engine room 15.

[0034] <Independent upper chamber> The independent upper room 23 is a room located above the independent room 22. As shown in FIG. 2, the independent upper room 23 is located inside the outer edge of the independent room 22 in a plan view. Furthermore, the independent upper room 23 in this embodiment is connected to the independent room 22. However, the independent upper room 23 does not have to be connected to the independent room 22. Furthermore, the independent upper room 23 is surrounded by steel plates, and the interior of the independent upper room 23 is not connected to the hold space 13. Because the independent upper room 23 is located on the deck 14, the independent upper room 23 can be considered a non-hazardous area.

[0035] <Branch aggregation equipment> The branching and aggregation device 24 is a non-explosion-proof device that branches or aggregates electrical wiring. The branching and aggregation device 24 includes a distribution board, a starter board, an inverter board, a transformer, and a field unit that receives multiple sensor signals. In this embodiment, the branching and aggregation device 24 is located in the internal passage 18. As described above, the internal passage 18 can be considered a non-hazardous area, and therefore the branching and aggregation device 24, which is non-explosion-proof electrical equipment, can be installed therein. Note that the branching and aggregation device 24 may be located in the lower extension chamber 19 or the inner extension chamber 20 instead of the internal passage 18.

[0036] Here, since the branching and consolidating device 24 is a non-explosion-proof electrical device, if the internal passage 18 is a hazardous area, the branching and consolidating device 24 needs to be installed in the stern accommodation area 16 located at the stern. In this case, the distance from the branching and consolidating device 24 to the electrical devices installed at various locations on the floating structure 100 becomes long, resulting in a complicated electrical wiring arrangement. In contrast, if the branching and consolidating device 24 is installed in the internal passage 18 or the like as in this embodiment, the electrical wiring connecting each electrical device to the branching and consolidating device 24 can be shortened, thereby simplifying the electrical wiring arrangement. In particular, in this embodiment, the deck room 21 is located above the branching and consolidating device 24. Therefore, when the electrical devices are installed in the deck room 21, the distance from the branching and consolidating device to the electrical devices becomes short, further simplifying the electrical wiring arrangement.

[0037] <Opening and closing door> The opening and closing door 25 is a door located on the surface of the lower extension chamber 19 opposite to the hold space 13. Fig. 1 shows the opening and closing door 25 in an open state, and Fig. 3 shows the opening and closing door 25 in a closed state. The opening and closing door 25 is located above the waterline, which is the line at the water surface when the floating structure 100 is floating on water. The opening and closing door 25 is a watertight door that does not allow water to enter, and is formed so as to slide inward and upward to open. However, the type of the opening and closing door 25 is not limited.

[0038] Because the opening and closing door 25 is configured as described above, by opening the opening and closing door 25, workers can exit from the lower extension room 19 to the outside of the floating structure 100, and can also enter the lower extension room 19 from the outside of the floating structure 100. Therefore, for example, workers can exit from the engine room 15 or the stern accommodation space 16 to the outside through the opening and closing door 25 by passing through the internal passage 18 and the lower extension room 19. This allows workers to safely exit from the internal passage 18 and the lower extension room 19 to the outside without having to go over the deck 14, even in rainy weather or at night. An elevator may be provided between the lower extension room 19 and the internal passage 18.

[0039] <Receiving box> The receiving box 26 is a device to which power cables of external equipment are connected. The receiving box 26 is installed in the lower extension room 19. As mentioned above, the inside of the lower extension room 19 can be considered a non-hazardous area, so the receiving box 26, which is electrical equipment that is not explosion-proof, can be installed therein. Furthermore, because the opening and closing door 25 is located on the side of the lower extension room 19 opposite the hold space 13, the receiving box 26 can be accessed from the outside by opening the opening and closing door 25. As a result, the power cables of external equipment can be connected to the receiving box 26 without having to be lifted up to the deck 14, for example.

[0040] <Connection port> The connection port 27 is a device for connecting fluid transfer equipment such as hoses and pipes of external equipment. The fluid transfer equipment of external equipment includes a fuel supply hose, a fresh water supply hose, a sewage discharge hose, and a bilge discharge hose. The connection port 27 is installed in the lower expansion chamber 19. Therefore, the connection port 27 can be accessed from the outside by opening the opening / closing door 25. As a result, the fluid transfer equipment of the external equipment can be connected to the connection port 27 without having to be lifted up to the deck 14, for example.

[0041] <Emergency stop button> The emergency stop button 28 is a push button switch for stopping work performed using the external equipment's fluid transfer equipment. In other words, when an operator presses the emergency stop button 28, work performed using the external equipment's fluid transfer equipment stops. The emergency stop button 28 is installed in the lower expansion chamber 19. As mentioned above, the interior of the lower expansion chamber 19 is a non-hazardous area, so the emergency stop button 28, which is a non-explosion-proof electrical device, can be installed in the lower expansion chamber 19. The emergency stop button 28 is located near the connection port 27 to which the external equipment's fluid transfer equipment is connected, so that when performing work using the external equipment's fluid transfer equipment, an operator can quickly stop the work if any abnormality occurs.

[0042] <Electric motor> The electric motor 29 is a motor for driving cargo equipment such as a cargo compressor that compresses so-called boil-off gas, which is the evaporated liquefied gas in the liquefied gas tank 12, or gas obtained by forcibly vaporizing liquefied gas. The electric motor 29 is mechanically connected to the cargo equipment. The electric motor 29 and the cargo equipment are installed in the upper deck room 21. As described above, the upper deck room 21 can be considered a non-hazardous area, and therefore the electric motor 29, which is electrical equipment, can be installed in the upper deck room 21. Note that if the upper deck 14 is a hazardous area, the upper deck room 21 needs to be raised to make the upper deck room 21 a non-hazardous area; however, in this embodiment, the upper deck 14 can be considered a non-hazardous area, and therefore raising the upper deck room 21 is not necessary.

[0043] In addition, when cargo equipment such as a cargo compressor, cargo pump, and cargo process unit (which shares gas fuel with the engine room 15) is arranged in the deck room 21 as in this embodiment, the room in which the cargo equipment is arranged (cargo equipment room) becomes a hazardous area. In that case, the deck room 21 can be divided so that the room in which the cargo equipment room is arranged becomes a hazardous area, and the room in which the electric motor 29 is installed becomes a non-hazardous area. In this case, the room in which the electric motor 29 is installed and the cargo equipment room are separated by an airtight wall, and the electric motor 29 is installed in one area separated by the airtight wall, and the cargo equipment is installed in the other area. In this case, the shaft of the electric motor 29 may pass through the airtight wall.

[0044] In this embodiment, since cargo equipment is installed in the deck room 21, the deck room 21 functions as a cargo equipment room. However, the cargo equipment room may be located in the aft portion (for example, above the engine room 15). In other words, a cargo equipment room different from the deck room 21 may be provided in the aft portion, and the electric motor 29 and cargo equipment may be installed in that cargo equipment room.

[0045] <Fuel cell> The fuel cell 30 is a device that generates electricity using liquefied gas stored in the liquefied gas tank 12 or naturally evaporating flammable gas (boil-off gas). The fuel cell 30 of this embodiment supplies power to each device on the floating structure 100. The power generated by the fuel cell 30 may drive a motor, which may assist the main engine or, instead of the main engine, rotate the screw propeller 43. The fuel cell 30 of this embodiment is installed in the independent chamber 22. As described above, the independent chamber 22 in which the fuel cell 30 is to be installed can be considered a non-hazardous area, so the fuel cell 30, which is an electrical device, can be installed therein. Furthermore, the independent chamber 22 is separated from the non-hazardous area. Therefore, even if flammable gas is generated from the fuel cell 30, the generated flammable gas will not flow into the non-hazardous area. No non-explosion-proof electrical equipment other than the fuel cell 30 is installed in the independent chamber 22 or the upper independent chamber 23.

[0046] In this embodiment, the fuel cell 30 is installed in the independent chamber 22, but it may also be installed in the upper independent chamber 23. The floating structure 100 may also be equipped with a secondary battery such as a lithium-ion battery instead of the fuel cell 30. In this case, the secondary battery is also installed in the independent chamber 22 or the upper independent chamber 23, and no non-explosion-proof electrical equipment other than the secondary battery is installed in the independent chamber 22 or the upper independent chamber 23. Furthermore, the floating structure 100 may also be equipped with both the fuel cell 30 and the secondary battery. In this case, two independent chambers 22 may be provided, one of which may be equipped with the fuel cell 30 and the secondary battery. Alternatively, the independent chamber 22 and the upper independent chamber 23 may be independent of each other, and the fuel cell 30 may be installed in one of them and the secondary battery in the other. For example, the secondary battery may store electricity generated by surplus boil-off gas for when a large amount of electricity is needed.

[0047] Furthermore, the fuel cell 30 can generate electricity using gas sent from the cargo equipment room and supply the electricity to the switchboard in the engine room 15. In this case, it is desirable that the fuel cell 30 be located between the cargo equipment room and the engine room 15. For example, when the deck room 21 functions as the cargo equipment room as in this embodiment, that is, when the cargo equipment room is located on the deck 14, it is desirable that the independent room 22 or the independent upper room 23 in which the fuel cell 30 is installed be located aft of the cargo equipment room and between adjacent liquefied gas tanks 12, or aft of the aftmost liquefied gas tank 12. On the other hand, when the cargo equipment room is located in the stern, it is desirable that the fuel cell 30 be located aft of the aftmost liquefied gas tank 12.

[0048] (summary) As described above, the floating structure of this embodiment comprises a liquefied gas tank that is strong enough to not require a secondary barrier, a hold space that accommodates the liquefied gas tank, an internal passage adjacent to the hold space, and an inner expansion chamber that communicates with the internal passage on the hold space side of the internal passage.

[0049] In the floating structure according to this embodiment, the internal passage and the inner extension chamber can be considered to be non-hazardous areas, so various non-explosion-proof electrical equipment can be installed in the internal passage and the inner extension chamber, improving the degree of freedom in designing the floating structure.

[0050] In addition, the floating structure according to this embodiment further includes a non-explosion-proof branching and aggregation device that branches or aggregates electrical wiring within the inner extension chamber.

[0051] In this way, if a non-explosion-proof branching and aggregation device is located inside the inner extension chamber, the electrical wiring connecting each electrical device to the branching and aggregation device can be shortened, simplifying the layout of the electrical wiring.

[0052] In addition, the floating structure of this embodiment is equipped with a liquefied gas tank that is strong enough to not require a secondary barrier, a hold space that accommodates the liquefied gas tank, an internal passage adjacent to the hold space, and a lower expansion chamber that communicates with the internal passage below the internal passage.

[0053] In the floating structure according to this embodiment, the lower extension chamber can be considered a non-hazardous area, so various non-explosion-proof electrical equipment can be installed in the lower extension chamber, improving the degree of freedom in designing the floating structure.

[0054] In addition, the floating structure according to this embodiment further includes an opening / closing door located on the surface of the lower extension chamber opposite to the hold space.

[0055] Therefore, according to the floating structure of this embodiment, by opening the opening and closing door, workers can exit the floating structure from the lower extension chamber and enter the lower extension chamber from the outside of the floating structure.

[0056] In addition, the floating structure according to this embodiment further includes a non-explosion-proof power receiving box in the lower extension chamber to which a power cable of an external facility can be connected.

[0057] Therefore, according to the floating structure of this embodiment, the non-explosion-proof receiving box can be accessed from the outside by opening the door, and as a result, the power cable of the external equipment can be connected to the receiving box without having to lift it up to the deck, for example.

[0058] In addition, the floating structure of this embodiment further includes a connection port in the lower expansion chamber to which fluid transfer equipment of external equipment can be connected, and a non-explosion-proof emergency stop button in the lower expansion chamber to stop work being performed using the fluid transfer equipment.

[0059] Therefore, according to the floating structure of this embodiment, the connection port can be accessed from the outside by opening the door. As a result, the fluid transfer equipment of the external equipment can be connected to the connection port without having to lift the external equipment fluid transfer equipment up to the deck, for example. Furthermore, since the non-explosion-proof emergency stop button is located near the connection port to which the external equipment fluid transfer equipment is connected, when performing work using the external equipment fluid transfer equipment, if any abnormality occurs, the worker can quickly stop the work. [Explanation of symbols]

[0060] 11 Hull 12 Liquefied gas tank 13 Hold Space 14 Deck 15 Engine Room 16 Stern living quarters 17 Boatswain's Storehouse 18 Internal passage 19 Lower expansion chamber 20 Inner expansion chamber 21 Upper deck room 22 Independent room 23 Independent suprachamber 24 Branching and aggregation equipment 25 Opening and closing doors 26 Receiving box 27 connection ports 28 Emergency stop button 29 Electric Motor 30 Fuel Cell 40 Tank cover 41 Ship's Bottom 42 Side wall 43 Screw propeller 44 Protrusion 45 Passage Door 46 Cargo elevator 100 Floating Structures

Claims

1. a liquefied gas tank having strength that does not require a secondary barrier; a hold space for accommodating the liquefied gas tank; an interior passageway adjacent to the hold space; an inner expansion chamber communicating with the internal passage on the hold space side of the internal passage; A floating structure comprising: a non-explosion-proof branching and aggregation device within the inner extension chamber that branches or aggregates electrical wiring.

2. a liquefied gas tank having strength that does not require a secondary barrier; a hold space for accommodating the liquefied gas tank; an interior passageway adjacent to the hold space; A floating structure comprising: a lower extension chamber communicating with the internal passage below the internal passage.

3. The floating structure according to claim 2 , further comprising an opening / closing door located on a surface of the lower extension chamber opposite to the hold space.

4. The floating structure according to claim 3 , further comprising a non-explosion-proof power receiving box in the lower extension chamber to which a power cable of an external facility can be connected.

5. a connection port in the lower expansion chamber to which fluid transfer equipment of external equipment can be connected; 5. The floating structure according to claim 3, further comprising a non-explosion-proof emergency stop button in the lower extension chamber for stopping work performed using the fluid transfer equipment.

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