Floating body

Abstract

To provide a floating body capable of efficiently recovering liquid gas leaked from a tank.SOLUTION: A floating body includes: a float body; a tank body provided on the float body and capable of pooling liquid gas inside; a tank having an insulation wall covering an exterior surface of the tank body; a receiving unit arranged below the tank to cover the tank from below, and having a receiving surface and a recess recessed more downwardly than the receiving surface; a pump provided in the recess; and a return line for returning the liquid gas pumped by the pump to the inside of the tank body.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This disclosure relates to a floating body.

Background Art

[0002] Patent Document 1 discloses an invention of a liquid leakage prevention device for a storage tank that stores liquids such as caustic soda and aqueous ammonia supplied into a cylinder to neutralize sulfuric acid used for EGR (Exhaust Gas Recirculation). In the technology described in Patent Document 1, the liquid leaked from the storage tank is recovered into the corming space.

[0003] By the way, liquefied gas carriers that use liquefied gases such as LPG (Liquefied Petroleum Gas), LNG (Liquefied Natural Gas), and ammonia as fuel or cargo are provided with liquefied gas tanks for storing liquefied gas. Even in such liquefied gas tanks, countermeasures are taken assuming that the liquefied gas, which is the liquid stored inside, leaks outside the liquefied gas tank. For example, in a liquefied gas carrier that uses liquefied gas as cargo, since it often has a plurality of cargo tanks, conventionally, the leaked liquefied gas has been recovered by introducing the liquefied gas leaked from one cargo tank into another cargo tank.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] On the other hand, in the case of liquefied gas-fueled vessels that use liquefied gas as fuel, they may not have multiple liquefied gas tanks like the liquefied gas carriers mentioned above. In such vessels that do not have multiple liquefied gas tanks, as described in Patent Document 1, it is not possible to transfer liquid leaked from one tank to another tank. Therefore, there is a problem in that leaked liquefied gas cannot be efficiently recovered.

[0006] This disclosure was made to solve the above-mentioned problems and aims to provide a floating device that can efficiently recover liquefied gas leaked from a tank. [Means for solving the problem]

[0007] To solve the above problems, the floating body according to this disclosure comprises a floating body body, a tank body provided on the floating body body and capable of storing liquefied gas inside, and a heat-insulating wall covering the outer surface of the tank body, and an IMO tank type B type tank in which the upper limit of the amount of liquefied gas leaking from the inside is calculated in advance, and the heat-insulating wall wall A guide portion is integrally formed with the outer surface of the tank body, covering the entire bottom surface from below, and is positioned below the tank to cover the tank from below. As a secondary defense Receiving surface 、 and recessed below the receiving surface As a secondary defense The guide section comprises a receiving section having a recess, a pump provided in the recess and capable of pressurizing more liquefied gas out of the recess than the amount of liquefied gas leaking from the tank per unit time, and a return line that returns the liquefied gas pressurized by the pump back into the tank body, the guide section comprising a guide surface that guides the leaked liquefied gas from below facing the bottom surface of the tank, a plurality of bottom grooves that recess downward from the guide surface and extend in the ship width direction, a central groove that recesses downward from the guide surface and extends in the bow-stern direction where the bottom grooves converge and connect, and a hole located on the stern side in the bow-stern direction on the inner wall surface of the central groove, the opening of the recess being located below the hole so as to allow the liquefied gas leaking from the tank through the hole to fall into the recess. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a floating device that can efficiently recover liquefied gas leaking from a tank. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view of a floating body according to an embodiment of the present disclosure. [Figure 2] This figure shows the configuration of the fuel storage unit according to the embodiment of this disclosure. [Figure 3] This diagram shows the configuration of a fuel storage unit according to another embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] The floating body according to the embodiment of this disclosure will be described below with reference to the drawings.

[0011] (Structure of the floating body) The floating vessel in this embodiment is a liquefied gas-fueled vessel that uses liquefied gas as fuel. More specifically, the floating vessel in this embodiment is an ammonia-fueled vessel that uses ammonia, which is a liquefied gas, as fuel. Although this embodiment describes an ammonia-fueled vessel as an example, the type of floating vessel is not limited to any particular type. Examples of floating vessel types include liquefied gas carriers, ferries, RO-RO ships, car carriers, passenger ships, and so on.

[0012] As shown in Figure 1, the floating body 1 comprises a floating body main body 10, a superstructure 20, a combustion device 30, a fuel storage section 40, and a fuel supply system 110.

[0013] (Floating body) As shown in Figure 1, the floating body 10 has at least two sides 11A, 11B, a bottom 12, and an upper deck 13. The side hulls 11A and 11B each have a pair of side hull outer plates forming the left and right side hulls 11A and 11B respectively. The bottom hull 12 has a double-bottom bottom hull outer plate connecting these side hulls 11A and 11B. The upper deck 13 is provided across the pair of side hull outer plates.

[0014] By these side hulls 11A and 11B, the bottom hull 12, and the upper deck 13, the outer shell of the floating body main body 10 forms a box shape in a cross-sectional view orthogonal to the ship's head and stern direction FA. Hereinafter, the direction extending from the stern 15 to the bow 14 of the floating body main body 10 is referred to as the "ship's head and stern direction FA".

[0015] (Superstructure) The superstructure 20 is a structure provided so as to face upward in the vertical direction Dv from the upper deck 13. In the superstructure 20, for example, a living area, a bridge, etc. are provided.

[0016] (Combustion device) The combustion device 30 is a device that generates thermal energy by burning fuel. The combustion device 30 is provided, for example, in a compartment such as an engine room (not shown) provided inside the floating body main body 10. Examples of the combustion device 30 include a main engine for propelling the floating body 1, an engine of a generator for supplying electricity to the ship, a boiler for generating steam as a working fluid, etc. The combustion device 30 in the present embodiment is a main engine that uses ammonia as fuel.

[0017] (Fuel storage section) The fuel storage section 40 stores liquefied ammonia as fuel for the combustion device 30 in a low-temperature state. Details of the configuration of the fuel storage section 40 will be described later.

[0018] (Fuel supply system) The fuel supply system 110 is a system that supplies ammonia as fuel from the fuel storage section 40 to the combustion device 30. The fuel supply system 110 in the present embodiment is provided, for example, inside the floating body main body 10. The fuel supply system 110 includes a supply line 111 (other line) and a return line 112 (other line). These supply line 111 and return line 112 are connected to a tank 41 and are pipes through which ammonia can flow inside.

[0019] The supply line 111 connects the tank 41 (details will be described later) of the fuel storage unit 40 and the combustion device 30. Ammonia as fuel flows from the tank 41 toward the combustion device 30 in the supply line 111. Therefore, ammonia is introduced into the combustion device 30 from the tank 41 via the supply line 111.

[0020] Note that the supply line 111 is provided with a pump (not shown) for pumping ammonia from the tank 41 to the combustion device 30, a heat exchanger (not shown) for heating the ammonia in the supply line 111 guided to the combustion device 30 by this pump, and the like. [[ID=I0]]

[0021] The return line 112 connects the combustion device 30 and the tank 41 of the fuel storage unit 40. One end of the return line II2 is connected to the combustion device 30, and the other end is connected to the tank 41. Ammonia remaining unburned in the combustion device 30 flows from the combustion device 30 toward the tank 41 in the return line 112. Therefore, the ammonia sent to the tank 41 by the return line 112 is reused for the combustion of the combustion device 30 by being supplied again into the supply line 111 in the tank 41.

[0022] One end of a flue 140, which is a duct for guiding the exhaust gas G generated in the combustion device 30 to the outside of the floating body main body 10, is connected to the combustion device 30. The other end of the flue 140 penetrates the upper deck 13 and extends to the upper side in the vertical direction Dv outside the floating body main body 10. Note that the portion of the flue 140 extending outside the floating body main body 10 as shown in FIG. 1 is surrounded by the hull structure 170 and the funnel 180.

[0023] (Fuel storage unit) In this embodiment, the fuel storage section 40 is located inside the floating body 10. As shown in Figure 2, the fuel storage unit 40 includes a tank 41, a receiving unit 70, a pump 80, a return line 90, and a leak detection unit 100.

[0024] Here, the floating body 10 further has an inner surface 16 that demarcates a hold space R for housing the tank 41. That is, the tank 41 is provided within the hold space R demarcated by the inner surface 16. In this embodiment, the inner surface 16 is formed, for example, by a partition wall provided inside the floating body 10. In Figure 2, for the sake of explanation, the shape of the partition wall forming the inner surface 16 is not explicitly shown.

[0025] The inner surface 16 of the floating body 10 includes a floor surface 16a corresponding to the bottom surface of the inner surface 16, a top surface 16b located above the floor surface 16a in the vertical direction Dv and facing the floor surface 16a, and a side surface 16c connecting the floor surface 16a and the top surface 16b in the vertical direction Dv. That is, the top surface 16b corresponds to the ceiling surface portion of the inner surface 16, and the side surface 16c corresponds to the side surface portion of the inner surface 16.

[0026] The inner surface 16 includes a total of four sides 16c: two sides 16c facing each other in the bow-stern direction FA, and two sides 16c facing each other in the width direction Dw, extending from one side 11A to the other side 11B. Note that in Figure 2, one of the two sides 16c facing each other in the width direction Dw is not shown.

[0027] Two opposing sides 16c in the bow-stern direction FA are connected to the ends of the top surface 16b in the bow-stern direction FA, respectively, by rising upward in the vertical direction Dv from each end of the floor surface 16a in the bow-stern direction FA. Two opposing sides 16c in the width direction Dw are connected to the ends of the top surface 16b in the width direction Dw, respectively, by rising upward in the vertical direction Dv from each end of the floor surface 16a in the width direction Dw.

[0028] (tank) Tank 41 is an IMO Type B tank for storing liquefied ammonia as fuel for the combustion device 30. Here, the IMO Type B tank is defined by the International Gas Carrier (IGC) Code, which is the safety regulation for liquefied gases established by the International Maritime Organization (IMO). Specifically, in an IMO Type B tank, the upper limit of the amount of liquefied gas fuel leaking from inside the tank per unit time is calculated based on a predetermined calculation method.

[0029] The tank 41 comprises a tank body 50 and a heat-insulating wall 60. For convenience, in Figure 2, the supply line 111 (another line) for supplying ammonia from the tank 41 to the combustion device 30, and the return line 112 (another line) for returning ammonia from the combustion device 30 to the tank 41 are shown as the same line.

[0030] The tank body 50 stores ammonia inside. In this embodiment, the tank body 50 is made of a low-temperature steel that does not lose its toughness even at low temperatures, such as nickel steel, stainless steel, or aluminum alloy. In this embodiment, the tank body 50 is made of a material that does not lose its toughness in the temperature range between -30°C and -40°C, which is around -33.34°C, the temperature at which ammonia condenses.

[0031] The tank body 50 has a top section 51, a bottom section 52, and side wall sections 53. The ceiling portion 51 forms the ceiling of the tank body 50. The ceiling portion 51 has an upper surface 51a that faces upward in the vertical direction Dv within the hold space R.

[0032] The bottom portion 52 forms the bottom part of the tank body 50. The bottom portion 52 has a bottom surface 52a that is located vertically Dv lower than the ceiling portion 51 within the hold space R and faces the floor surface 16a.

[0033] The side wall portion 53 connects the ceiling portion 51 and the bottom portion 52 in the vertical direction Dv and also forms the side wall portion of the tank body 50. That is, the side wall portion 53 has a side surface 53a that connects the upper surface 51a of the ceiling portion 51 and the bottom surface 52a of the bottom portion 52.

[0034] Specifically, the side wall portion 53 has four sides 53a that are opposite to the four sides 16c of the inner surface 16. Therefore, the outer surface of the tank body 50 is formed by the upper surface 51a of the ceiling portion 51, the side surface 53a of the side wall portion 53, and the bottom surface 52a of the bottom portion 52.

[0035] The heat barrier wall 60 is an insulating material that covers the outer surface of the tank body 50. The heat barrier wall 60 suppresses natural heat input into the tank body 50 from the atmosphere inside the hold space R. The heat-insulating wall 60 has a heat-insulating section 61 and a guide section 62.

[0036] The heat-insulating section 61 covers the entire upper surface 51a and the entire side surface 53a of the outer surface of the tank body 50 from the outside. The heat-insulating section 61 insulates to prevent heat from being conducted to the tank body 50 from the atmosphere inside the hold space R. In other words, the heat-insulating section 61 exhibits an insulating function that prevents natural heat input to the tank body 50. In this embodiment, the heat-insulating section 61 is formed of a material such as foamed polyurethane.

[0037] The heat-insulating section 61 includes a ceiling heat-insulating section 61a and a side wall heat-insulating section 61b. The ceiling heat shield 61a is formed to cover the entire upper surface 51a of the ceiling portion 51 of the tank body 50 from the upper side in the vertical direction Dv.

[0038] The side wall heat shield 61b is formed to cover the entire side surface 53a of the side wall 53 of the tank body 50 from the bow-stern direction FA and the width direction Dw. The side wall heat shield 61b has a contact surface 61c that faces and contacts the side surface 53a of the side wall 53. In this embodiment, the ceiling heat-insulating section 61a and the side wall heat-insulating section 61b are formed integrally.

[0039] The side wall heat-insulating portion 61b has a plurality of side wall grooves 54a that are recessed from the contact surface 61c toward the side surface 16c of the inner surface 16 and extend in the vertical direction Dv. The lower end of these side wall grooves 54a in the vertical direction Dv reaches the lower end of the side wall heat-insulating portion 61b in the vertical direction Dv.

[0040] The guide section 62 covers the entire bottom surface 52a of the outer surface of the tank body 50 from the downward side in the vertical direction Dv. The guide section 62 is connected to the downward end of the side wall heat-insulating section 61b of the heat-insulating section 61 and is formed integrally with the heat-insulating section 61.

[0041] The guide section 62, like the heat shield section 61, provides insulation to prevent natural heat input to the tank body 50. In this embodiment, the guide section 62 is formed of a material such as foamed polyurethane. However, the heat shield section 61 and the guide section 62 do not have to be made of foamed polyurethane. Furthermore, the heat shield section 61 and the guide section 62 may be made of different materials.

[0042] The guide section 62 faces the bottom surface 52a of the bottom section 52 from the downward side in the vertical direction Dv, and has a guide surface 62a that guides ammonia leaked from the tank body 50. The guide surface 62a is inclined to be located downwards within the hold space R as the ship moves from the bow 14 side to the stern 15 side in the bow-stern direction FA. For convenience, Figure 2 shows the floating body 10 in an even-trim state. That is, the guide surface 62a is inclined with respect to a hypothetical horizontal plane perpendicular to the direction of gravity.

[0043] The guide section 62 has a plurality of bottom grooves 54b that are recessed from the guide surface 62a toward the floor surface 16a and extend in the ship width direction Dw, and a single central groove 54c that is recessed from the guide surface 62a toward the floor surface 16a and extends in the bow-stern direction FA at the center of the guide section 62. This central groove 54c extends from the bow 14 side to the stern 15 side in the bow-stern direction FA of the guide section 62. The ends of the central groove 54c on the bow 14 side and the stern 15 side in the bow-stern direction FA are connected to the lower end in the vertical direction Dv of at least one of the plurality of side wall grooves 54a formed in the side wall heat shield section 61b.

[0044] The bottom groove 54b is in the guide section 62 boat It extends from the end side in the width direction Dw so as to converge into the central groove 54c, and is connected so as to merge with the central groove 54c. One end of the bottom groove 54b is connected to the lower end in the vertical direction Dv of the side wall groove 54a formed in the side wall heat shield portion 61b. The other end of the bottom groove 54b is connected to the central groove 54c.

[0045] Therefore, the side wall grooves 54a of the side wall heat-insulating portion 61b, the bottom groove 54b of the guide portion 62, and the central groove 54c constitute a groove 54 that extends continuously from the contact surface 61c of the side wall heat-insulating portion 61b to the guide surface 62a of the guide portion 62.

[0046] As a result, even if tiny cracks or holes occur in various places in the tank body 50, and ammonia leaks from the inside of the tank body 50 to the outside through these tiny cracks or holes, this leaked ammonia will travel along the groove 54 between the tank body 50 and the heat shield wall 60, moving from the side surface 53a to the bottom surface 52a.

[0047] The guide section 62 has a hole 62c that penetrates downward from the guide surface 62a. Specifically, the hole 62c is located on the inner wall surface of the central groove 54c on the stern 15 side in the bow-stern direction FA.

[0048] Therefore, ammonia that leaks from the tank body 50 and moves along the side wall groove 54a towards the bottom surface 52a either flows directly into the central groove 54c or into the central groove 54c via the bottom groove 54b. The ammonia that flows into the central groove 54c flows through the groove 54c according to the slope and then falls downward from the guide section 62 through the hole 62c.

[0049] (Receiving part) The receiving section 70 collects and stores ammonia leaking from the tank 41. The receiving section 70 is positioned below the tank 41 so as to cover the entire guide section 62 of the heat shield wall 60 from below. The receiving portion 70 has a receiving surface 71 and a recess 72 formed on the stern side 15 in the bow-stern direction FA from the receiving surface 71. In this embodiment, the receiving portion 70 also serves as the floor surface 16a of the inner surface 16 of the floating body 10.

[0050] The receiving surface 71 is a surface that acts as a secondary barrier, receiving liquefied ammonia when liquefied ammonia leaking from the guide section 62 in the heat-insulating wall 60 of the tank body 50 falls onto the receiving surface 71, and guiding the received liquefied ammonia to the recess 72.

[0051] In this embodiment, the secondary barrier refers to a barrier provided to prevent damage to components of the floating body 10 other than the tank 41 from being damaged due to low temperatures resulting from contact between liquefied ammonia leaking from the tank body 50 and the components of the floating body 10.

[0052] The receiving surface 71 is made of a material (low-temperature steel) that maintains its toughness even at low temperatures, similar to the tank body 50. Of the inner surfaces 16 in this embodiment, the top surface 16b and the side surfaces 16c are made of a metal other than low-temperature steel. Here, during navigation, the floating body 10 is inclined with respect to the horizontal plane so that it sinks downward in the vertical direction Dv as it moves from the bow 14 side to the stern 15 side. That is, the floating body 10 is sailing in a stern trim state.

[0053] Therefore, the receiving surface 71 is inclined so that it is located downwards as you move from the bow 14 side to the stern 15 side in the bow-stern direction FA (the inclination is not shown in the diagram). Note that the inclination of the receiving surface 71 is not shown in the diagram. As a result, liquefied ammonia that falls onto the receiving surface 71 moves towards the stern 15 side according to the inclination of the receiving surface 71.

[0054] The recess 72 is a pit (well) that serves as a secondary barrier, formed to be recessed vertically Dv downward from the receiving surface 71. The recess 72 is formed to store ammonia leaked from the tank 41. The recess 72 is made of a material (low-temperature steel) that maintains its toughness even at low temperatures, similar to the tank body 50. When liquefied ammonia leaked into the recess 72 accumulates, the material forming the recess 72 (low-temperature steel) cools, and the temperature of the recess 72 decreases.

[0055] In this embodiment, the recess 72 has an opening 72a that opens into the hold space R. This opening 72a is located below the hole 62c at the stern end of the guide section 62 in the bow-stern direction FA on the stern 15 side. Here, the guide surface 62a of the guide portion 62 of the heat shield wall 60 is inclined to approach the recess 72 as it moves toward the recess 72.

[0056] (pump) Pump 80 is a diaphragm pump located inside the recess 72. Pump 80 pumps the ammonia accumulated inside the recess 72 out of the recess 72. Pump 80 is driven and controlled by a pump drive unit 102 located outside the recess 72.

[0057] In this embodiment, the pump 80 can pump more liquefied ammonia out of the recess 72 per unit time than the amount of liquefied ammonia leaking from the tank per unit time.

[0058] Here, since the pump 80 is a diaphragm pump, which is a type of positive displacement pump, it can be run dry. In this embodiment, dry running means that the pump 80 can continue its normal suction operation even without introducing liquefied ammonia as a driving fluid into the pump 80. In other words, the pump 80 can operate without causing abnormalities such as galling or seizing, even when there is no liquefied ammonia in the recess 72.

[0059] (Return line) The return line 90 is a pipe that returns the ammonia in the recess 72, which is pumped by the pump 80, back into the tank body 50. One end of the return line 90 is connected to the pump 80. The other end of the return line 90 extends into the interior of the tank body 50, penetrating the heat-insulating portion 61 of the heat-insulating wall 60 of the tank 41 and the ceiling portion 51 of the tank body 50.

[0060] Here, the return line 90 is not connected to the supply line 111 (another line) and the return line 112 (another line) that connect the tank 41 and the combustion device 30. In other words, the ammonia flowing through the return line 90 does not directly flow into the supply line 111 and the return line 112. That is, the return line 90 is located in the hold space R independently of the supply line 111 and the return line 112.

[0061] (Leak detection unit) The leak detection unit 100 detects that liquefied ammonia leaked from the tank 41 has accumulated in the recess 72, and drives the pump 80 based on the detection information. The leak detection unit 100 includes a leak sensor 101 and a pump drive device 102.

[0062] The leak sensor 101 is a temperature sensor installed on the wall surface of the recess 72. The leak sensor 101 acquires temperature data of the wall surface of the recess 72 at predetermined time intervals and transmits a signal indicating this temperature data to the pump drive unit 102, which is located outside the recess 72. The leak sensor 101 and the pump drive unit 102 are connected by wire or wireless.

[0063] The pump drive unit 102 is a device that acquires temperature information from the temperature data of the wall surface of the recess 72 acquired by the leak sensor 101, and controls the drive of the pump 80 based on this temperature information.

[0064] Specifically, when the pump drive unit 102 detects that the temperature obtained from the leak sensor 101 is below a predetermined threshold, it determines that liquefied ammonia has accumulated in the recess 72 and sends a signal to the pump 80 to instruct it to drive.

[0065] When the pump 80 receives a signal from the pump drive unit 102 to instruct it to drive, it pumps the liquefied ammonia accumulated in the recess 72 towards the tank 41 through the return line 90.

[0066] Pump 80 continues to run dry (continues suction operation) even after it has finished pumping the liquefied ammonia accumulated in recess 72. In this embodiment, the pump 80 is stopped by human intervention at a suitable timing.

[0067] Furthermore, if the leak sensor 101 detects that the temperature it obtains is greater than a predetermined threshold, the pump drive unit 102 may determine that no liquefied ammonia has accumulated in the recess 72 and send a signal to the pump 80 to stop driving (dry running). In this case, when the pump 80 receives the signal to stop driving sent from the pump drive unit 102, it will stop driving.

[0068] (Effects and Benefits) According to the configuration of the floating body 1 in the above embodiment, ammonia leaking from the tank 41 falls into the receiving section 70 and accumulates in the recess 72 of the receiving section 70. The ammonia accumulated in the recess 72 of the receiving section 70 is pumped by the pump 80 through the return line 90 and returned to the inside of the tank body 50. Therefore, ammonia leaking from the tank 41 and accumulated in the receiving section 70 can be efficiently recovered.

[0069] Furthermore, according to the configuration of the floating body 1 as described above, since the receiving portion 70 is the floor surface 16a on the inner surface 16, the receiving portion 70 can be formed without increasing the number of parts of the floating body 1.

[0070] Furthermore, according to the configuration of the floating body 1 in the above embodiment, the pump 80 is driven based on the detection information from the leak sensor 101. Therefore, the ammonia in the recess 72 can be returned to the tank body 50 at a suitable timing.

[0071] Furthermore, according to the configuration of the floating body 1 in the above embodiment, the pump 80 can pump more liquefied ammonia out of the recess 72 per unit time than the amount of liquefied ammonia leaking from the tank body 50 per unit time, thus suppressing the accumulation of ammonia in the recess 72. Therefore, it is possible to suppress the vaporization of ammonia that has moved from inside the tank body 50 into the recess 72 within the hold space R.

[0072] Furthermore, according to the configuration of the floating body 1 in the above embodiment, liquefied ammonia leaking from the tank body 50 is guided to the bottom surface 52a side of the tank body 50 by traveling through the groove 54 between the tank body 50 and the heat shield 61. The liquefied ammonia guided to the bottom surface 52a side falls into the recess 72 of the receiving part 70 through the hole 62c formed in the central groove 54c of the guide part 62 of the heat shield wall 60. Therefore, ammonia leaking from the tank body 50 can be efficiently guided into the recess 72.

[0073] Furthermore, since the guide surface 62a of the guide section 62 is inclined to approach the recess 72 as it moves toward the recess 72, it is possible to suppress the liquefied ammonia from falling onto the receiving surface 71. Therefore, the area of ​​the secondary barrier formed of low-temperature steel on the receiving surface 71 can be reduced, and the costs incurred in manufacturing the floating body 1 can be reduced.

[0074] Furthermore, according to the configuration of the floating body 1 as described above, a supply line 111 and a return line 112 through which ammonia can flow are connected to the tank 41, and the return line 90 is independent of these supply lines 111 and return line 112 as other lines. In other words, when ammonia in the recess 72 flows toward the tank 41, it does not flow into the supply line 111 and return line 112. As a result, when the pump 80 returns ammonia to the tank 41 through the return line 90, it is not necessary to stop the flow of ammonia from the tank 41 to the combustion device 30 and from the combustion device 30 to the tank 41 via the supply line 111. Therefore, for example, with the pump 80 running continuously, ammonia leaking from the tank 41 can be continuously returned to the tank 41 through the return line 90.

[0075] Furthermore, according to the configuration of the floating body 1 in the above embodiment, since the pump 80 can be run dry, even if ammonia leaking from the tank 41 moves into the recess 72 of the receiving portion 70, it is immediately returned to the tank 41. Therefore, it is possible to further suppress the vaporization of ammonia that has moved into the recess 72 within the hold space R.

[0076] [Other embodiments] While embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to that of the embodiments, and additions, omissions, substitutions, and other modifications to the configuration are possible without departing from the spirit of this disclosure. Furthermore, this disclosure is not limited by the embodiments, but is limited only by the claims.

[0077] In this embodiment, the floating body 1 is a vessel that uses ammonia as fuel, but it is not limited to a vessel that uses ammonia as fuel. The floating body 1 may use liquefied gas such as LNG or LPG as fuel. That is, the tank 41 is not limited to a configuration that stores ammonia, and the tank 41 may be configured to store liquefied gas such as LNG or LPG.

[0078] Furthermore, the ceiling portion 51 of the tank body 50 in the embodiment may have a ceiling portion body that forms the upper surface 51a and a trunk top that extends upward in the vertical direction Dv from the upper surface 51a of the ceiling portion body. If the ceiling portion 51 has a trunk top and the trunk top is provided outside the hold space R, then a ceiling heat shield portion 61a does not need to be formed on the trunk top.

[0079] Furthermore, as shown in Figure 2, the guide surface 62a in the embodiment is inclined to be located downward from the bow 14 side to the stern 15 side in the bow-stern direction FA when the floating body 10 is not trimmed, but the configuration is not limited to this. The guide surface 62a may be configured to be inclined with respect to the horizontal plane only by the stern trim of the floating body 10 while it is in motion.

[0080] Furthermore, in this embodiment, the return line 90 is provided independently of the supply line 111 and the return line 112, but the configuration is not limited to this. That is, the return line 90 may be connected to the supply line 111 or the return line 112. In other words, the inside of the return line 90 conduit may be in communication with the inside of the conduits of the supply line 111 and the return line 112.

[0081] Furthermore, the pump 80 in the embodiment is not limited to a diaphragm pump, which is a type of positive displacement pump. The pump 80 may be, for example, another positive displacement pump such as a piston pump, or a non-positive displacement pump.

[0082] Furthermore, although the embodiment describes the supply line 111 and the return line 112 as other lines, the other lines are not limited to these. The other lines may be, for example, cargo lines that are connected to the tank 41 during bunkering and can supply ammonia supplied from, for example, a bunkering station outside the floating body 1 into the tank 41. Even in this case, the return line 90 may be in a state where it is not connected to the cargo line, that is, the return line 90 is independent of the cargo line, and the ammonia flowing through the return line 90 does not flow into the cargo line.

[0083] Furthermore, in this embodiment, the leak sensor 101 of the leak detection unit 100 is a temperature sensor, but it is not limited to a temperature sensor. The leak sensor 101 may be a level sensor that acquires the height of the liquid level of the liquefied gas accumulated in the recess 72, or a liquefied gas sensor that acquires the concentration of the liquefied gas in the atmosphere inside the hold space R, etc. In this case, the pump drive device 102 of the leak detection unit 100 can acquire detection information from the detection data acquired by the leak sensor 101 and send a signal to the pump 80 to drive based on this detection information.

[0084] Furthermore, as shown in Figure 3, the fuel storage section 40 of the floating body 1 may also be further provided with a drip pan as a receiving section 700, which is positioned below the tank 41 and covers the tank 41 from below, and has a receiving surface 710 and a recess 720 that is recessed below the receiving surface 710. In this case, the floor surface 16a described in the above embodiment does not have to be the receiving section 70. The same effect as described above can still be obtained.

[0085] [Note] The floating body described in the embodiment can be understood, for example, as follows:

[0086] (1) The floating body 1 according to the first embodiment comprises a floating body body 10, a tank 41 provided on the floating body body 10 and having a tank body 50 capable of storing liquefied gas inside, and a heat-insulating wall 60 covering the outer surface of the tank body 50, a receiving portion 70, 700 positioned below the tank 41 and covering the tank 41 from below, having receiving surfaces 71, 710 and recesses 72, 720 that are recessed below the receiving surfaces 71, 710, a pump 80 provided in the recesses 72, 720, and a return line 90 that returns the liquefied gas pumped by the pump 80 back into the tank body 50.

[0087] As a result, the liquefied gas leaking from the tank 41 falls into the receiving section 70,700 and accumulates in the recesses 72,720 of the receiving section 70,700. The liquefied gas accumulated in the recesses 72,720 of the receiving section 70,700 is pumped by the pump 80 through the return line 90 and returned to the inside of the tank body 50.

[0088] (2) The floating body 1 according to the second embodiment is the floating body 1 of (1), wherein the floating body body 10 has an inner surface 16 that defines a hold space R for housing the tank 41 inside, and the receiving portion 70 may be the floor surface 16a of the inner surface 16.

[0089] As a result, since the receiving portion 70 is the floor surface 16a of the inner surface 16 of the floating body 10, the number of parts of the floating body 1 is not increased.

[0090] (3) The float 1 according to the third embodiment is the float 1 of (1) or (2), further comprising a leak sensor 101 that detects when the liquefied gas has accumulated in the recesses 72,720, and the pump 80 may be driven based on the detection information of the leak sensor 101.

[0091] This allows the pump 80 to be driven based on the detection information from the leak sensor 101.

[0092] (4) The float 1 according to the fourth embodiment is any of the float 1 from (1) to (3), which is connected to the tank 41 and further comprises other lines through which the liquefied gas can flow, and the return line 90 may be independent of the other lines.

[0093] This prevents ammonia in recesses 72 and 720 from flowing into other lines as it flows through the return line 90 towards the tank 41.

[0094] (5) The floating body 1 according to the fifth embodiment is any of the floating bodies 1 from (1) to (4), and the pump 80 may be capable of dry operation.

[0095] As a result, even if liquefied gas leaking from tank 41 moves into recesses 72,720 of receiving sections 70,700, it is immediately returned to tank 41 by the dry-running pump 80. [Explanation of symbols]

[0096] 1…Floating body 10…Floating body main body 11A,11B…Side 12…Bottom 13…Upper deck 14…Bow 15…Stern 16…Interior 16a…Floor 16b…Top 16c,53a…Sides 20…Superstructure 30…Combustion device 40…Fuel storage 41…Tank 50…Tank body 51…Ceiling 51a…Top surface 52…Bottom 52a…Bottom surface 53…Side wall 54…Groove 54a…Side wall groove 54b…Bottom groove 60…Heat shield 61…Heat shield 62…Guidance section 62a…Guidance surface 62c…Hole 70,700…Receiving section 71,710…Receiving surface 72,720…Recess 72a…Opening 80…Pump 90…Return line 100... Leak detection unit 101... Leak sensor 102... Pump drive unit 110... Fuel supply system 111... Supply line 112... Return line 140... Flue Dv... Vertical direction Dw... Width direction FA... Bow and stern direction G... Exhaust gas R... Hold space

Claims

1. The floating body and A tank of the IMO tank type B type, provided on the floating body, having a tank body capable of storing liquefied gas inside, and a heat-insulating wall covering the outer surface of the tank body, wherein the upper limit of the amount of liquefied gas leaking from the inside is predetermined, A guide portion is formed integrally with the heat-insulating wall and covers the entire bottom surface of the outer surface of the tank body from below, A receiving portion is positioned below the tank so as to cover the tank from below, and has a receiving surface as a secondary protective wall, and a recess that is recessed below the receiving surface as a secondary protective wall, A pump provided within the recess is capable of pumping more liquefied gas out of the recess than the amount of liquefied gas leaking from the tank per unit time. A return line for returning the liquefied gas pumped by the pump back into the tank body, Equipped with, The aforementioned induction unit is The bottom surface of the tank body has a guide surface that directs the leaked liquefied gas from below, Multiple bottom grooves that are recessed downward from the guide surface and extend in the direction of the ship's width, A central groove that is recessed downward from the guide surface and extends in the bow-stern direction, and where the bottom grooves merge and connect, A hole located on the aft side in the bow-stern direction on the inner wall surface of the central groove, Equipped with, The opening of the recess is located below the hole so that the liquefied gas leaking from the tank through the hole can fall into the recess. A floating object.

2. The floating body has an inner surface that demarcates a hold space for housing the tank inside, The floating body according to claim 1, wherein the receiving portion is the inner surface of the floor.

3. The system further includes a leak sensor that detects when the liquefied gas has accumulated in the recess, The floating body according to claim 1 or 2, wherein the pump is driven based on the detection information of the leak sensor.

4. The tank is connected to the aforementioned tank and further comprises other lines through which the liquefied gas can flow, The float according to any one of claims 1 to 3, wherein the return line is independent of the other lines.

5. The floating body according to any one of claims 1 to 4, wherein the pump is capable of dry operation.

Images