Floating body

Abstract

To reduce cost while suppressing occurrence of trouble due to erosion by suppressing vaporization of ammonia.SOLUTION: A floating body includes: a fuel tank retaining ammonia; a first pressure tank storing the ammonia in a pressurized state; a supply line for deriving the ammonia from the first pressure tank; a pressure raising pump for raising pressure of the ammonia flowing in the supply line; an engine to which the ammonia is supplied as fuel through the supply line; a first return line for returning the ammonia passed through the engine to the first pressure tank; a first pressure adjustment valve provided in the first return line and capable of adjusting pressure of the ammonia in the engine; a cooling unit provided on the downstream side of the first pressure adjustment valve in the first return line for cooling the ammonia; and a pressure retaining unit for retaining pressure of the ammonia between the first adjustment valve of the first return line and the cooling unit to be lower than pressure of the ammonia in the engine and retaining it to pressure capable of maintaining the ammonia in the liquid state.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a floating body. [Background technology]

[0002] Patent Document 1 discloses a marine fuel supply system including a supply line for supplying liquefied ammonia stored in an ammonia storage tank to a main engine, and a return line for returning the liquefied ammonia from the main engine to the ammonia storage tank. In Patent Document 1, the liquefied ammonia returned from the main engine is cooled in a heat exchanger and its pressure is reduced by a first Joule-Thomson valve before being returned to the ammonia storage tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Registration No. 3234399 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, the liquefied ammonia returned from the main engine is cooled in a heat exchanger before the pressure is reduced, which requires a heat exchanger with high pressure resistance, making it difficult to reduce costs. Also, depending on the pressure of the ammonia storage tank, a gas-liquid mixed state may occur after the first Joule-Thomson valve, which may cause erosion in the piping. The present disclosure has been made in consideration of the above circumstances, and provides a float that can prevent problems such as thinning due to erosion by handling the ammonia in the piping in the liquid phase rather than in a gas-liquid mixed state, while also enabling cost reduction by using a cooling section with low pressure resistance. [Means for solving the problem]

[0005] In order to solve the above problems, the following configuration is adopted. According to a first aspect of the present disclosure, a float includes a float body, a fuel tank provided in the float body and storing ammonia, a first pressurized tank in which the ammonia from the fuel tank is stored in a pressurized state, a supply line through which the ammonia is discharged from the first pressurized tank, a boost pump that pressurizes the ammonia flowing through the supply line, an engine to which the ammonia is supplied as fuel via the supply line, a first return line that returns the ammonia that has passed through the engine to the first pressurized tank, a first pressure regulating valve provided in the first return line and capable of adjusting the pressure of the ammonia in the engine, a cooling unit provided downstream of the first pressure regulating valve in the first return line and cooling the ammonia, and a pressure maintaining unit that maintains a pressure of the ammonia between the first pressure regulating valve and the cooling unit in the first return line lower than the pressure of the ammonia in the engine and capable of maintaining the ammonia in a liquid state. Effect of the Invention

[0006] According to the float of the present disclosure, the ammonia in the piping is handled in the liquid phase rather than in a gas-liquid mixed state, which prevents problems such as thinning due to erosion, and costs can be reduced by using a cooling section with low pressure resistance. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a side view of the floating body according to the first embodiment of the present disclosure. [Diagram 2] FIG. 1 is a diagram showing a schematic configuration of an ammonia fuel supply system in a first embodiment of the present disclosure. [Diagram 3] FIG. 5 is a view corresponding to FIG. 2 in a second embodiment of the present disclosure. [Figure 4] FIG. 5 is a view corresponding to FIG. 3 in a third embodiment of the present disclosure. [Diagram 5] FIG. 5 is a diagram corresponding to FIG. 4 in a modified example of the third embodiment of the present disclosure. [Figure 6] FIG. 11 is a view corresponding to FIG. 4 in a fourth embodiment of the present disclosure. [Figure 7] FIG. 10 is a view corresponding to FIG. 5 in a modified example of the fourth embodiment of the present disclosure. [Figure 8] FIG. 11 is a view corresponding to FIG. 4 in a fifth embodiment of the present disclosure. [Figure 9] FIG. 11 is a view corresponding to FIG. 5 in a modified example of the fifth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [First embodiment] Hereinafter, a floating body according to a first embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a side view of the floating body according to the first embodiment of the present disclosure. (Floating structure) As shown in Fig. 1, the float 1 of this embodiment includes a float body 2, an upper structure 4, a combustion device 8, an ammonia tank 10, an ammonia fuel supply system 20, and a fuel supply device room 30. The float 1 of this embodiment will be described as an example of a ship that can navigate by a main engine or the like. The type of ship of the float 1 is not limited to a specific type of ship. Examples of the type of ship of the float 1 include a liquefied gas carrier, a ferry, a RORO ship, a car carrier, and a passenger ship.

[0009] The floating body 2 has a pair of side panels 5A, 5B that form its outer hull, and a ship bottom 6. The side panels 5A, 5B each have a pair of side panel shells that form the starboard and port sides, respectively. The ship bottom 6 has a bottom panel shell that connects the side panels 5A, 5B. The pair of side panels 5A, 5B and the ship bottom 6 give the outer hull of the floating body 2 a U-shape in cross section perpendicular to the bow-stern direction FA.

[0010] The floating body main body 2 further comprises an upper deck 7, which is a full-length deck located at the topmost layer. The superstructure 4 is formed on this upper deck 7. Accommodation areas and the like are provided within the superstructure 4. In the floating body 1 of this embodiment, for example, a cargo space (not shown) for carrying cargo is provided on the bow 3a side in the bow-stern direction FA from the superstructure 4.

[0011] The combustion device 8 is a device that generates thermal energy by burning fuel, and is provided in the floating body main body 2. Examples of the combustion device 8 include an internal combustion engine used in the main engine for propelling the floating body 1, an internal combustion engine used in a power generation facility that supplies electricity to the ship, and a boiler that generates steam as a working fluid. The combustion device 8 of this embodiment is capable of using at least ammonia as a fuel. Note that the combustion device 8 may be configured to be capable of switching between ammonia and another fuel, such as diesel, different from ammonia.

[0012] The ammonia tank (fuel tank) 10 is a tank that stores liquid ammonia (in other words, liquefied ammonia). In this embodiment, a case is illustrated in which the ammonia tank 10 is installed on the upper deck 7 closer to the stern 3b than the superstructure 4. The ammonia tank 10 of this embodiment stores liquefied ammonia as fuel for the combustion device 8.

[0013] The ammonia fuel supply system 20 connects the combustion device 8 and the ammonia tank 10, and is configured to be able to supply at least the ammonia stored in the ammonia tank 10 to the combustion device 8.

[0014] The fuel supply device room 30 is a section that houses ammonia fuel equipment that constitutes part of the ammonia fuel supply system 20. In this embodiment, the fuel supply device room 30 is illustrated as being provided on the upper deck 7 on the bow 3a side of the superstructure 4, but the location of the fuel supply device room 30 is not limited to being on the upper deck 7 on the bow 3a side of the superstructure 4. The above-mentioned ammonia fuel supply system 20 connects the combustion device 8 and the ammonia tank 10 via the inside of this fuel supply device room 30.

[0015] FIG. 2 is a diagram showing a schematic configuration of an ammonia fuel supply system in the first embodiment of the present disclosure. 2, the ammonia fuel supply system 20 of the first embodiment includes a fuel tank discharge line 41, a low pressure pump 42, a first heat exchanger 43, a first pressurized tank 44, a supply line 45, a booster pump 46, a first return line 47, a first pressure regulating valve 48, a first pressure sensor 49, a first flow rate sensor 50, a second heat exchanger (cooling unit) 51, a second pressure regulating valve (pressure holding unit) 52, a second pressure sensor 53, a first liquid level adjusting unit 54, a first inert gas supply unit 55, a first gas release unit 56, a fuel tank return line 57, a flow rate regulating valve 58, a supply return line 59, a third pressure regulating valve 60, and a third pressure sensor 61. Although not shown, an inert gas supply device for performing fuel purging is separately connected to the ammonia fuel supply system 20.

[0016] The fuel tank outlet line 41 discharges liquefied ammonia (hereinafter simply referred to as ammonia) from the ammonia tank 10 toward the first pressurized tank 44. The fuel tank outlet line 41 connects the liquid phase of the ammonia tank 10 and the first pressurized tank 44. The low-pressure pump 42 is provided in the fuel tank outlet line 41, and pressurizes the ammonia in the ammonia tank 10 (for example, to about 2.5 MPa) and sends it out toward the first pressurized tank 44. The low-pressure pump 42 may be a so-called deep well type or submerged type that is directly installed in the tank.

[0017] The first heat exchanger 43 is provided in the fuel tank outlet line 41 and adjusts the temperature of the ammonia pressurized by the low-pressure pump 42. In this embodiment, the ammonia is heated to a temperature of, for example, about 40° C.

[0018] The first pressurized tank 44 stores the ammonia introduced from the ammonia tank 10 in a pressurized state. The first pressurized tank 44 in this embodiment is in a pressurized state at a pressure (e.g., about 2.3 MPa) slightly lower than the pressure of the ammonia immediately after it is pressurized by the low-pressure pump 42.

[0019] The supply line 45 draws ammonia from the first pressurized tank 44. The supply line 45 supplies the liquid phase ammonia from the first pressurized tank 44 to the engine. The boost pump 46 is provided in the supply line 45 and boosts the pressure of the ammonia discharged from the first pressurized tank 44. The boost pump 46 is capable of boosting the pressure of the ammonia flowing through the supply line 45 to a pressure equal to or higher than that required by the engine.

[0020] The first return line 47 returns the ammonia that has passed through the engine to the first pressurized tank 44. In other words, the first return line 47 is a line that returns surplus ammonia that has been supplied to the engine by the supply line 45 and not combusted by the engine to the first pressurized tank 44. The first return line 47 in this embodiment returns the ammonia that has passed through the engine to the first pressurized tank 44.

[0021] The first pressure sensor 49 detects the pressure of the ammonia flowing in the first return line 47 on the engine side relative to the first pressure regulating valve 48. The detection result of the first pressure sensor 49 is input to the first pressure regulating valve 48. The first flow rate sensor 50 detects the flow rate of ammonia flowing through the first return line 47 on the pressurized tank side relative to the first pressure regulating valve 48. The detection result of the first flow rate sensor 50 is input to the first pressure regulating valve 48.

[0022] The first pressure regulating valve 48 is provided in the first return line 47 and is capable of adjusting the pressure of ammonia in the engine. The pressure of ammonia in the engine is maintained at a predetermined pressure (for example, about 8 MPa) required in the engine by adjusting the opening degree of the first pressure regulating valve 48. That is, the boost pump 46 boosts the pressure of ammonia to a pressure higher than the predetermined pressure required in the engine, and the first pressure regulating valve 48 increases the valve opening degree when the pressure of ammonia in the engine is high based on the detection result of the first pressure sensor 49, while decreasing the valve opening degree when the pressure of ammonia in the engine is low. Moreover, the first pressure regulating valve 48 adjusts the valve opening degree so that the flow rate of ammonia flowing in the first return line 47 exceeds a predetermined lower limit value based on the detection result of the first flow rate sensor 50, regardless of the detection result of the first pressure sensor 49. In this way, by making the flow rate of ammonia exceed the predetermined lower limit value, for example, it is possible to suppress the ammonia from becoming overheated or the components in the engine from becoming overheated.

[0023] The second heat exchanger 51 is provided on the first return line 47 downstream of the first pressure regulating valve 48. The second heat exchanger 51 cools the ammonia flowing through the first return line 47. More specifically, the second heat exchanger 51 cools the ammonia flowing through the first return line 47 to a temperature at which the ammonia remains in a liquid state and does not vaporize when the ammonia is returned to the first pressurized tank 44. Here, in the first pressurized tank 44 of this embodiment, ammonia is stored at about 2.3 MPa as described above, and the second heat exchanger 51 cools the ammonia to 45° C. or less at which the ammonia does not vaporize under this pressure.

[0024] The second pressure sensor 53 detects the pressure of ammonia flowing through the first return line 47 between the first pressure regulating valve 48 and the second pressure regulating valve 52. The detection result of the second pressure sensor 53 is input to the second pressure regulating valve 52.

[0025] The second pressure regulating valve 52 is provided between the second heat exchanger 51 of the first return line 47 and the first pressurized tank 44. The second pressure regulating valve 52 is capable of regulating the pressure of ammonia flowing at least between the first pressure regulating valve 48 of the first return line 47 and the second heat exchanger 51. The second pressure regulating valve 52 of this embodiment maintains the pressure in the first return line 47 between the first pressure regulating valve 48 and the second pressure regulating valve 52 at a pressure lower than the pressure of ammonia in the engine and capable of maintaining the ammonia in a liquid state, based on the detection result of the second pressure sensor 53. More specifically, the second pressure regulating valve 52 adjusts the ammonia to a pressure (e.g., about 3.25 MPa) at which the ammonia maintains a liquid state at the ammonia temperature (e.g., 70° C.) immediately after the ammonia flows from the engine through the first return line 47 and passes through the first pressure regulating valve 48.

[0026] The first liquid level adjustment unit 54 maintains the liquid level of the first pressurized tank 44 within a predetermined range. The first liquid level adjustment unit 54 includes a first liquid level detection unit 62 and a first liquid level adjustment valve 63. The first liquid level detection unit 62 detects the liquid level of the first pressurized tank 44. The detection result of the first liquid level detection unit 62 is input to the first liquid level adjustment valve 63. The first liquid level adjustment valve 63 adjusts the valve opening based on the detection result of the first liquid level detection unit 62, thereby adjusting the flow rate of ammonia flowing from the ammonia tank 10 to the first pressurized tank 44.

[0027] The first inert gas supply unit 55 supplies an inert gas into the first pressurized tank 44. The first inert gas supply unit 55 is capable of supplying an inert gas having the same pressure (e.g., 2.3 MPa) as the pressure in the first pressurized tank 44 or a slightly higher pressure (e.g., 2.35 MPa) into the first pressurized tank 44. When the pressure in the first pressurized tank 44 drops too much, for example, due to a drop in the liquid level in the first pressurized tank 44, the first inert gas supply unit 55 supplies an inert gas into the first pressurized tank 44 to prevent a drop in pressure in the first pressurized tank 44. As a result, the inert gas supplied by the first inert gas supply unit 55 is stored in the gas phase in the first pressurized tank 44.

[0028] The first gas release section 56 discharges the gas in the gas phase in the first pressurized tank 44 to the outside of the first pressurized tank 44. The first gas release section 56 of the present embodiment releases the gas in the gas phase in the first pressurized tank 44 to the atmosphere when the pressure in the first pressurized tank 44 rises too much (for example, when it rises to about 2.36 to 2.8 MPa) due to, for example, a rise in the liquid level in the first pressurized tank 44. In other words, the first inert gas supply section 55 and the first gas release section 56 maintain the pressure in the first pressurized tank 44 within a predetermined pressure range.

[0029] The fuel tank return line 57 is a line that diverts the ammonia flowing through the fuel tank outlet line 41 toward the first pressurized tank 44 and returns it to the ammonia tank 10. The flow rate control valve 58 is provided in the fuel tank return line 57 and controls the flow rate of ammonia flowing through the fuel tank return line 57. For example, when the liquid level in the first pressurized tank 44 is at a predetermined upper limit, the fuel tank return line 57 and the flow rate control valve 58 return excess ammonia to the ammonia tank 10. When the low-pressure pump 42 is a variable flow rate type pump, the fuel tank return line 57 and the flow rate control valve 58 may be omitted.

[0030] The supply return line 59 is connected to the supply line 45 as a branch, and is connected to the fuel tank outlet line 41 between the first liquid level control valve 63 and the first heat exchanger 43. That is, the supply return line 59 returns the ammonia flowing through the supply line 45 to the first pressurized tank 44 via the first heat exchanger 43. The third pressure sensor 61 detects the pressure in the supply return line 59. The detection result of the third pressure sensor 61 is input to the third pressure regulating valve 60. Note that the third pressure sensor 61 may detect the pressure in a portion of the supply line 45 that is closer to the engine than the boost pump 46.

[0031] The third pressure regulating valve 60 is provided in the supply return line 59. The third pressure regulating valve 60 is capable of adjusting the flow rate of ammonia flowing through the supply return line 59. In other words, the third pressure regulating valve 60 is capable of adjusting the pressure in the supply line 45 on the engine side of the boost pump 46 by releasing ammonia through the supply return line 59. The third pressure regulating valve 60 of this embodiment maintains the pressure in the supply line 45 on the engine side of the boost pump 46 at a predetermined pressure or less based on the detection result of the third pressure sensor 61. Note that in this embodiment, the third pressure regulating valve 60 is used as a valve for releasing ammonia to prevent overpressure in the supply line 45, and the first pressure regulating valve 48 adjusts the pressure of ammonia supplied to the engine. However, the third pressure regulating valve 60 may adjust the pressure of ammonia supplied to the engine. Furthermore, the boost pump 46 may be equipped with an inverter to have a function of adjusting the discharge pressure.

[0032] (Action and effect) According to the float 1 of the first embodiment, the fuel in the engine can be adjusted to the required pressure by the first pressure regulating valve 48 provided in the first return line 47. In addition, even if the ammonia flowing through the first return line 47 is decompressed downstream of the first pressure regulating valve 48, the second pressure regulating valve 52 can easily maintain the pressure at which the liquid state can be maintained. Therefore, while arranging the second heat exchanger 51 (cooling unit) downstream of the first pressure regulating valve 48, which has a low pressure, it is possible to suppress the vaporization of ammonia between the first pressure regulating valve 48 and the second heat exchanger 51. Therefore, by treating the ammonia in the piping in the liquid phase rather than in a gas-liquid mixed state, it is possible to suppress the occurrence of troubles such as erosion, and it is also possible to use the second heat exchanger 51, which has a low pressure resistance, thereby reducing costs.

[0033] Furthermore, in the above first embodiment, since the first liquid level detection unit 62 that detects the liquid level in the first pressurized tank 44 and the first liquid level adjustment valve 63 that adjusts the flow rate of ammonia supplied to the first pressurized tank 44 are provided, the liquid level in the first pressurized tank 44 can be easily maintained within a predetermined liquid level range in response to engine load fluctuations, etc. As a result, the incorporation of air bubbles into the supply line 45 can be suppressed.

[0034] [Second embodiment] Next, a second embodiment of the present disclosure will be described with reference to the drawings. The float of the second embodiment is obtained by adding a second pressurized tank 70 to the first embodiment described above. Therefore, FIG. 1 of the first embodiment will be used to describe the same parts as those of the first embodiment described above, with the same reference numerals assigned, and duplicated descriptions will be omitted.

[0035] The float 101 in the second embodiment includes a float body 2, an upper structure 4, a combustion device 8, an ammonia tank 10, an ammonia fuel supply system 20, and a fuel supply device room 30.

[0036] FIG. 3 is a diagram corresponding to FIG. 2 in the second embodiment of the present disclosure. As shown in FIG. 3, the ammonia fuel supply system 20 of the second embodiment includes a fuel tank outlet line 41, a low-pressure pump 42, a first heat exchanger 43, a first pressurized tank 44, a supply line 45, a boost pump 46, a first return line 47, a first pressure regulating valve 48, a first pressure sensor 49, a first flow rate sensor 50, a second heat exchanger (cooling unit) 51, a second pressure regulating valve (pressure holding unit) 52, a second pressure sensor 53, a first liquid level detection unit 62, a first liquid level regulating valve 63, a first inert gas supply unit 55, a first gas release unit 56, a fuel tank return line 57, a flow rate regulating valve 58, a supply return line 59, a third pressure regulating valve 60, and a third pressure sensor 61, as in the first embodiment. Furthermore, the ammonia fuel supply system 20 of the second embodiment includes, in addition to the above, a second pressurized tank 70, a second inert gas supply unit 71, a second gas release unit 72, a second liquid level adjustment unit 73, a bypass line 74, a first switching valve 75, and a second switching valve 76.

[0037] The second pressurized tank 70 is provided in the first return line 47 between the second heat exchanger 51 and the first pressurized tank 44. The second pressurized tank 70 is capable of storing the ammonia flowing through the first return line 47. The second pressurized tank 70 has a liquid phase and a gas phase therein. An upstream line 47A of the first return line 47 that is upstream of the second pressurized tank 70 is connected to the second pressurized tank 70. In addition, a downstream line 47B of the first return line 47 that is downstream of the second pressurized tank 70 is connected to the liquid phase of the second pressurized tank 70.

[0038] The second inert gas supply unit 71 supplies an inert gas into the second pressurized tank 70. The second inert gas supply unit 71 can supply an inert gas having the same pressure (e.g., 2.5 MPa) as the pressure in the second pressurized tank 70 or a slightly higher pressure (e.g., 2.55 MPa) into the second pressurized tank 70. When the pressure in the second pressurized tank 70 drops too much, for example, due to a drop in the liquid level in the second pressurized tank 70, the second inert gas supply unit 71 supplies an inert gas into the second pressurized tank 70 to prevent a drop in pressure in the second pressurized tank 70. As a result, the inert gas supplied by the second inert gas supply unit 71 is stored in the gas phase in the second pressurized tank 70.

[0039] The second gas release section 72 discharges the gas in the gas phase of the second pressurized tank 70 to the outside of the second pressurized tank 70. The second gas release section 72 of this embodiment releases the gas in the gas phase of the second pressurized tank 70 to the atmosphere when the pressure in the second pressurized tank 70 rises too much (for example, when it rises to 3.0 MPa or more), for example, due to a rise in the liquid level in the second pressurized tank 70. In other words, the second inert gas supply section 71 and the second gas release section 72 maintain the pressure in the second pressurized tank 70 within a predetermined pressure range.

[0040] The second liquid level adjustment unit 73 maintains the liquid level of the second pressurized tank 70 within a predetermined range. The second liquid level adjustment unit 73 includes a second liquid level detection unit 77 and a second liquid level adjustment valve 78. The second liquid level detection unit 77 detects the liquid level of the second pressurized tank 70. The detection result of the second liquid level detection unit 77 is input to the second liquid level adjustment valve 78. The second liquid level control valve 78 adjusts the flow rate of ammonia discharged from the second pressurized tank 70 through the downstream line 47B of the first return line 47 by adjusting the valve opening based on the detection result of the second liquid level detection unit 77.

[0041] The bypass line 74 is a line that allows the ammonia flowing through the upstream line 47A to bypass the second pressurized tank 70 and flow into the downstream line 47B. The first switching valve 75 is provided in the upstream line 47A. More specifically, the first switching valve 75 is provided in the upstream line 47A on the second pressurized tank 70 side relative to the branch point of the bypass line 74. This first switching valve 75 is normally open, and is closed when an abnormality occurs, for example, when the liquid level adjustment function of the second pressurized tank 70 fails. The second switching valve 76 is provided in the bypass line 74. The second switching valve 76 is normally closed and is opened when an abnormality such as that described above occurs. In other words, the first switching valve 75 and the second switching valve 76 make it possible to switch the destination of the ammonia flowing through the upstream line 47A to either the second pressurized tank 70 or the bypass line 74.

[0042] (Action and effect) According to the float 101 of the second embodiment, in addition to the effects of the first embodiment, since the second pressurized tank 70 is provided in the middle of the first return line 47, when purging ammonia from the fuel system for maintenance, fuel switching, etc., it becomes possible to recover liquid ammonia by the second pressurized tank 70. In addition, at that time, the amount of purge gas flowing into the first pressurized tank 44 can be reduced, so the capacity of the first pressurized tank 44 can be reduced.

[0043] Furthermore, since the second inert gas supply unit 71 can form a gas phase in the second pressurized tank 70, it is possible to suppress the mixing of air bubbles into the liquid phase. Also, since the second inert gas supply unit 71 can supply an inert gas into the second pressurized tank 70, it is possible to suppress the pressure in the second pressurized tank 70 from decreasing and the liquid ammonia from evaporating.

[0044] In addition, the second embodiment is provided with a second liquid level detection unit 77 that detects the liquid level in the second pressurized tank 70, and a second liquid level control valve that adjusts the flow rate of ammonia discharged from the second pressurized tank 70 through the first return line 47. Therefore, even if the flow rate of liquid ammonia flowing into the second pressurized tank 70 or the flow rate of liquid ammonia discharged from the second pressurized tank 70 fluctuates due to engine load fluctuations, etc., the liquid level in the second pressurized tank 70 can be easily maintained within a predetermined liquid level range.

[0045] [Third embodiment] Next, a third embodiment of the present disclosure will be described with reference to the drawings. The float of the third embodiment differs from the float of the second embodiment in that a canned motor pump is used as the boost pump. Therefore, FIG. 1 of the first embodiment will be used to describe the same parts as those of the first embodiment, and the same reference numerals will be used to denote the same parts as those of the first embodiment, and duplicated descriptions will be omitted.

[0046] The float 201 in the third embodiment includes a float main body 2, an upper structure 4, a combustion device 8, an ammonia tank 10, an ammonia fuel supply system 20, and a fuel supply device room 30.

[0047] FIG. 4 is a diagram corresponding to FIG. 3 in the third embodiment of the present disclosure. As shown in FIG. 4, the ammonia fuel supply system 20 of the third embodiment includes a fuel tank outlet line 41, a low-pressure pump 42, a first heat exchanger 43, a first pressurized tank 44, a supply line 45, a canned motor pump 146, a second return line 80, a first return line 47, a first pressure regulating valve 48, a first pressure sensor 49, a first flow rate sensor 50, a second heat exchanger (cooling unit) 51, a second pressure regulating valve (pressure retention unit) 52, and a second pressure The fuel tank is equipped with a sensor 53, a first liquid level detection unit 62, a first liquid level adjustment valve 63, a first inert gas supply unit 55, a first gas release unit 56, a fuel tank return line 57, a flow rate adjustment valve 58, a supply return line 59, a third pressure adjustment valve 60, a third pressure sensor 61, a second pressurized tank 70, a second inert gas supply unit 71, a second gas release unit 72, a second liquid level adjustment unit 73, a bypass line 74, a first switching valve 75, and a second switching valve 76.

[0048] The canned motor pump 146 is provided in the supply line 45 and boosts the pressure of the ammonia discharged from the first pressurized tank 44, similar to the boost pump 46 in the first embodiment. The canned motor pump 146 is capable of boosting the pressure of the ammonia flowing through the supply line 45 to a pressure equal to or higher than that required by the engine. The canned motor pump 146 is a type of pump in which a pump body (not shown) and a motor section (not shown) are integrally formed and which does not have a shaft seal. This canned motor pump 146 uses a portion of the ammonia flowing through the supply line 45 as a coolant for the motor section.

[0049] The second return line 80 is a line for returning a portion of the ammonia used as a coolant in the canned motor pump 146 to the gas phase of the first pressurized tank 44. In addition, when the temperature of the ammonia used as a coolant in the canned motor pump 146 is higher than the upper limit temperature of the ammonia stored in the first pressurized tank 44, a third heat exchanger 81 may be provided in the second return line 80 to cool the temperature of the ammonia flowing through the second return line 80 to a temperature lower than the above-mentioned upper limit temperature.

[0050] (Action and effect) In the third embodiment, the canned motor pump 146 is used, so that ammonia leakage from the shaft seal does not occur, and therefore reliability can be improved. Furthermore, since the first inert gas supply unit 55 can form a gas phase in the first pressurized tank 44, it is not necessary to return the ammonia used as the coolant for the canned motor pump 146 to a tank having a gas phase, such as a fuel tank, installed at a location distant from the canned motor pump 146. Therefore, even if the ammonia used as the coolant for the canned motor pump 146 is contaminated with oil or the like, it is possible to prevent the ammonia outside the fuel supply system of the engine from being contaminated. Furthermore, since a gas phase is formed in the first pressurized tank 44, it is possible to prevent air bubbles from being mixed into the liquid phase of ammonia. Furthermore, by supplying an inert gas into the first pressurized tank 44, it is possible to prevent the pressure in the first pressurized tank 44 from decreasing and the liquid ammonia from evaporating.

[0051] (Modification of the third embodiment) FIG. 5 is a diagram corresponding to FIG. 4 in a modified example of the third embodiment of the present disclosure. In the above-described third embodiment, a case where one canned motor pump 146 is provided as a boost pump has been described as an example. However, the number of boost pumps that boost the ammonia flowing through the supply line 45 is not limited to one.

[0052] For example, as in the float of the modified third embodiment shown in Fig. 5, the float may have a plurality of boost pumps provided in series in the supply line 45. In this modified third embodiment, a first canned motor pump 246A and a second canned motor pump 246B are provided as two boost pumps. Furthermore, the float of the modified third embodiment is provided with a second return line 80 for returning a part of the ammonia used as a coolant in the first canned motor pump 246A to the gas phase of the first pressurized tank 44, and a third return line 280 for returning a part of the ammonia used as a coolant in the second canned motor pump 246B to the gas phase of the first pressurized tank 44.

[0053] According to the modified example of the third embodiment, even if the ammonia pressure required by the engine differs depending on, for example, the manufacturer, the ammonia pressure can be boosted to the pressure required by the engine by adding or removing the boost pump. Furthermore, since multiple boost pumps are provided in series, it is possible to reduce costs by using an inexpensive canned motor pump, compared to a case in which the ammonia flowing through the supply line 45 is boosted by a single pump to a pressure equal to or higher than that required by the engine.

[0054] As in the third embodiment described above, when the temperature of the ammonia returned from the first and second canned motor pumps 246A and 246B to the gas phase of the first pressurized tank 44 is high, the ammonia may be cooled by providing a third heat exchanger 81 in the second return line 80 or a fourth heat exchanger 281 in the third return line 280, as necessary. Also, a fifth heat exchanger 85 for cooling the ammonia discharged from the second canned motor pump 246B may be provided. In a situation where the fifth heat exchanger 85 is provided, the above-mentioned first heat exchanger 43 may be omitted in some cases.

[0055] In the modified example of the third embodiment, two boost pumps are provided, but three or more boost pumps may be provided. Furthermore, a plurality of boost pumps may be provided in series in the supply line 45 of the first embodiment.

[0056] [Fourth embodiment] Next, a fourth embodiment of the present disclosure will be described with reference to the drawings. The float of the fourth embodiment differs from the third embodiment in that a return destination for a part of the ammonia used as a coolant in the canned motor pump is added. Therefore, FIG. 1 of the first embodiment will be used to describe the same parts as those of the third embodiment, with the same reference numerals given to them, and duplicated descriptions will be omitted.

[0057] The float 301 in the fourth embodiment includes a float body 2, an upper structure 4, a combustion device 8, an ammonia tank 10, an ammonia fuel supply system 20, and a fuel supply device room 30.

[0058] FIG. 6 is a diagram corresponding to FIG. 4 in the fourth embodiment of the present disclosure. As shown in FIG. 6, the ammonia fuel supply system 20 of the fourth embodiment includes a fuel tank outlet line 41, a low-pressure pump 42, a first heat exchanger 43, a first pressurized tank 44, a supply line 45, a canned motor pump 146, a second return line 80, a fourth return line 180 (second pressurized tank return line), a third switching valve 91, a fourth switching valve 92, a first return line 47, a first pressure regulating valve 48, a first pressure sensor 49, a first flow rate sensor 50, a second heat exchanger (cooling unit) 51, The fuel tank is equipped with a second pressure regulating valve (pressure retention section) 52, a second pressure sensor 53, a first liquid level detection section 62, a first liquid level regulating valve 63, a first inert gas supply section 55, a first gas release section 56, a fuel tank return line 57, a flow rate control valve 58, a supply return line 59, a third pressure regulating valve 60, a third pressure sensor 61, a second pressurized tank 70, a second inert gas supply section 71, a second gas release section 72, a second liquid level regulating section 73, a bypass line 74, a first switching valve 75, and a second switching valve 76.

[0059] The canned motor pump 146 has a configuration similar to that of the canned motor pump 146 of the third embodiment, and is provided in the supply line 45 to pressurize the ammonia discharged from the first pressurized tank 44. The canned motor pump 146 uses a portion of the ammonia flowing through the supply line 45 as a coolant for the motor unit.

[0060] The second return line 80 is a line for returning a portion of the ammonia used as a coolant in the canned motor pump 146 to the gas phase of the first pressurized tank 44. The fourth return line 180 is a line for returning a portion of the ammonia used as a coolant in the canned motor pump 146 to the gas phase of the second pressurized tank 70.

[0061] The third switching valve 91 adjusts the flow rate of ammonia flowing through the second return line 80. The fourth switching valve 92 adjusts the flow rate of ammonia flowing through the fourth return line 180. These third switching valve 91 and fourth switching valve 92 are configured to be freely opened and closed from fully open to fully closed. These third switching valve 91 and fourth switching valve 92 allow a part of the ammonia used as a coolant in the canned motor pump 146 to be distributed between the first pressurized tank 44 and the second pressurized tank 70. For example, by opening the third switching valve 91 and closing the fourth switching valve 92, a part of the ammonia used as a coolant in the canned motor pump 146 can be returned to the gas phase of the first pressurized tank 44. On the other hand, by closing the third switching valve 91 and opening the fourth switching valve 92, a part of the ammonia used as a coolant in the canned motor pump 146 can be returned to the gas phase of the second pressurized tank 70.

[0062] In the present embodiment, the third switching valve 91 is provided in the second return line 80, and the fourth switching valve 92 is provided in the fourth return line 180, but the present invention is not limited to this configuration. Any configuration may be used as long as a part of the ammonia used as a coolant in the canned motor pump 146 can be distributed between the first pressurized tank 44 and the second pressurized tank 70. In addition, although the third switching valve 91 and the fourth switching valve 92 are described as being capable of adjusting the flow rate, they may be valves that can only be opened and closed. In this case, the return destination of the part of the ammonia used as a coolant in the canned motor pump 146 is selectively selected from the first pressurized tank 44 and the second pressurized tank 70.

[0063] In addition, when the temperature of the ammonia used as a coolant in the canned motor pump 146 is higher than the upper limit temperature of the ammonia stored in the first pressurized tank 44 or the second pressurized tank 70, a third heat exchanger 81 may be provided in the second return line 80 to cool the temperature of the ammonia flowing through the second return line 80 to a temperature lower than the above-mentioned upper limit temperature, or a sixth heat exchanger 93 may be provided in the fourth return line 180 to cool the temperature of the ammonia flowing through the fourth return line 180 to a temperature lower than the above-mentioned upper limit temperature.

[0064] (Action and effect) In the fourth embodiment, in addition to the effects of the third embodiment, it becomes possible to selectively return ammonia used as a cooling liquid for the canned motor pump 146 to the first pressurized tank 44 and the second pressurized tank 70 in which a gas phase is formed.

[0065] (Modification of the fourth embodiment) FIG. 7 is a diagram corresponding to FIG. 5 in a modified example of the fourth embodiment of the present disclosure. In the above-described fourth embodiment, a case where one canned motor pump 146 is provided as a boost pump has been described as an example. However, the number of boost pumps that boost the ammonia flowing through the supply line 45 is not limited to one.

[0066] For example, as in the float of the modification of the fourth embodiment shown in Fig. 7, the float may have a plurality of boost pumps provided in series in the supply line 45. In this modification of the fourth embodiment, a first canned motor pump 246A and a second canned motor pump 246B are provided as two boost pumps. Furthermore, in the float of the modification of the fourth embodiment, in order to selectively return ammonia used as a cooling liquid for the canned motor pump 246A to the first pressurized tank 44 and the second pressurized tank 70 in which a gas phase is formed, a second return line 80, a fourth return line 180 (second pressurized tank return line), a third switching valve 91, and a fourth switching valve 92 are provided in the same manner as in the fourth embodiment.

[0067] Furthermore, in the float of the modified example of the fourth embodiment, a third return line 280, a fifth return line 380 (second pressurized tank return line), a fifth switching valve 94, and a sixth switching valve 95 are provided to selectively return ammonia used as a cooling liquid for the second canned motor pump 246B to the first pressurized tank 44 and the second pressurized tank 70 in which a gas phase is formed.

[0068] The third return line 280 is a line for returning a portion of the ammonia used as a coolant in the second canned motor pump 246B to the gas phase of the first pressurized tank 44. The fifth return line 380 is a line for returning a portion of the ammonia used as a coolant in the second canned motor pump 246B to the gas phase of the second pressurized tank 70.

[0069] The fifth switching valve 94 adjusts the flow rate of ammonia flowing through the third return line 280. The sixth switching valve 95 adjusts the flow rate of ammonia flowing through the fifth return line 380. The fifth switching valve 94 and the sixth switching valve 95 are configured to be freely openable and closable from fully open to fully closed. The fifth switching valve 94 and the sixth switching valve 95 allow a part of the ammonia used as a coolant in the canned motor pump 246B to be distributed between the first pressurized tank 44 and the second pressurized tank 70. For example, by opening the fifth switching valve 94 and closing the sixth switching valve 95, a part of the ammonia used as a coolant in the canned motor pump 246B can be returned to the gas phase of the first pressurized tank 44. On the other hand, by closing the fifth switching valve 94 and opening the sixth switching valve 95, a part of the ammonia used as a coolant in the canned motor pump 246B can be returned to the gas phase of the second pressurized tank 70.

[0070] (Action and effect) According to the modification of the fourth embodiment, even if the ammonia pressure required by the engine differs depending on, for example, the manufacturer, the ammonia pressure can be boosted to the pressure required by the engine by adding or removing the boost pump. Furthermore, since a plurality of boost pumps are provided in series, it is possible to reduce costs by using an inexpensive canned motor pump, compared to a case in which the ammonia flowing through the supply line 45 is boosted by a single pump to a pressure equal to or higher than that required by the engine. In addition, in the modified example of the fourth embodiment, it is possible to distribute and return the ammonia used as a cooling liquid for the first canned motor pump 246A and the second canned motor pump 246B to the first pressurized tank 44 and the second pressurized tank 70, respectively, in which a gas phase is formed.

[0071] In addition, as in the above-described modified example of the third embodiment, when the temperature of the ammonia returned from the first and second canned motor pumps 246A and 246B to the gas phase of the first pressurized tank 44 or the second pressurized tank 70 is high, the ammonia flowing through the second return line 80, the third return line 280, the fourth return line 180, and the fifth return line 380 may be cooled by providing a third heat exchanger 81 in the second return line 80, a fourth heat exchanger 281 in the third return line 280, a sixth heat exchanger 93 in the fourth return line 180, or a seventh heat exchanger 96 in the fifth return line 380, respectively. In addition, in the modified example of the fourth embodiment, the case where two canned motor pumps are provided has been described, but three or more canned motor pumps may be provided. In this case, ammonia may be selectively returned from each canned motor pump to the first pressurized tank 44 and the second pressurized tank 70.

[0072] [Fifth embodiment] Next, a fifth embodiment of the present disclosure will be described with reference to the drawings. The float of the fifth embodiment is different from the third embodiment described above in the return destination of a part of the ammonia used as a coolant in the canned motor pump. Therefore, the same parts as those of the third embodiment described above will be described with the same reference numerals as those of the first embodiment, and duplicated descriptions will be omitted.

[0073] The float 401 in the fifth embodiment includes a float body 2, an upper structure 4, a combustion device 8, an ammonia tank 10, an ammonia fuel supply system 20, and a fuel supply device room 30.

[0074] FIG. 8 is a diagram corresponding to FIG. 4 in the fifth embodiment of the present disclosure. As shown in FIG. 8, the ammonia fuel supply system 20 of the fifth embodiment includes a fuel tank discharge line 41, a low-pressure pump 42, a first heat exchanger 43, a first pressurized tank 44, a supply line 45, a canned motor pump 146, a fourth return line 180 (second pressurized tank return line), a first return line 47, a first pressure regulating valve 48, a first pressure sensor 49, a first flow rate sensor 50, a second heat exchanger 51, a second pressure regulating valve 52, a second pressure sensor 53, a fuel tank return line 57, a supply return line 59, a third pressure regulating valve 60, a third pressure sensor 61, a second pressurized tank 70, a second inert gas supply unit 71, a second gas release unit 72, a second liquid level adjustment unit 73, a bypass line 74, a first switching valve 75, a second switching valve 76, a fourth pressure sensor 162, and a fourth pressure regulating valve 158.

[0075] The canned motor pump 146 of the fifth embodiment returns the ammonia used as a coolant for the motor section only to the gas phase of the second pressurized tank 70 through the fourth return line 180. In other words, the ammonia used as a coolant for the motor section of the canned motor pump 146 is not returned to the first pressurized tank 44.

[0076] Moreover, the first pressurized tank 44 of the fifth embodiment is managed so as not to form a gas phase therein. In other words, the first pressurized tank 44 is filled with liquefied ammonia. Therefore, the first inert gas supply unit 55 and the first gas discharge unit 56, which are provided for the purpose of maintaining the pressure of the gas phase in each of the above-mentioned embodiments, are not connected to the first pressurized tank 44 of the fifth embodiment. Note that, for the purpose of purging the inside of the first pressurized tank 44, a configuration for supplying an inert gas and a configuration for discharging the gas inside the first pressurized tank 44 may be provided.

[0077] In addition, since the first pressurized tank 44 of the fifth embodiment is managed so as not to form a gas phase, a fourth pressure sensor 162 for detecting the liquid pressure in the first pressurized tank 44 is provided instead of the first liquid level detection unit 62 of the first embodiment. Furthermore, a fourth pressure regulating valve 158 is provided instead of the flow rate regulating valve 58 of the first embodiment. The fourth pressure regulating valve 158 adjusts the valve opening based on the detection result of the fourth pressure sensor 162. The fourth pressure regulating valve 158 adjusts the pressure in the first pressurized tank 44 so that it does not exceed a predetermined upper limit pressure. In addition, in the fifth embodiment, a sixth heat exchanger 93 may be provided in the fourth return line 180 as in the fourth embodiment.

[0078] (Action and effect) According to the fifth embodiment, it is not necessary to adjust the liquid level because it is not necessary to form a gas phase in the first pressurized tank 44. In addition, the pressure in the first pressurized tank 44 can be adjusted by the low-pressure pump 42, so that the number of parts can be reduced and the configuration can be simplified.

[0079] (Modification of the fifth embodiment) FIG. 9 is a diagram corresponding to FIG. 5 in a modified example of the fifth embodiment of the present disclosure. In the above-described fifth embodiment, a case has been described as an example in which one canned motor pump 146 is provided as the boost pump. However, the number of boost pumps that boost the ammonia flowing through the supply line 45 is not limited to one.

[0080] For example, like the float of the modified fifth embodiment shown in Fig. 9, it may have multiple canned motor pumps arranged in series on the supply line 45. This modified fifth embodiment includes two canned motor pumps, a first canned motor pump 246A and a second canned motor pump 246B, similar to the modified third embodiment and the modified fourth embodiment described above.

[0081] In the modification of the fifth embodiment, the ammonia used as a coolant for the motor of the first canned motor pump 246A is returned from the first canned motor pump 246A to the gas phase of the second pressurized tank 70 through the fourth return line 180. Similarly, the ammonia used as a coolant for the motor of the second canned motor pump 246B is returned from the second canned motor pump 246B to the gas phase of the second pressurized tank 70 through the fifth return line 380 (second pressurized tank return line). In other words, neither of the ammonia used as a coolant for the motor of the first canned motor pump 246A nor the second canned motor pump 246B is returned to the first pressurized tank 44. Note that the ammonia flowing through the fourth return line 180 and the fifth return line 380 may be cooled by providing a sixth heat exchanger 93 in the fourth return line 180 or a seventh heat exchanger 96 in the fifth return line 380.

[0082] (Action and effect) According to the modification of the fifth embodiment, even if the ammonia pressure required by the engine differs depending on, for example, the manufacturer, the ammonia pressure can be increased to the pressure required by the engine by adding or removing the boost pump. Furthermore, since a plurality of boost pumps are provided in series, it is possible to reduce costs by using an inexpensive canned motor pump, compared to a case where a single pump is used to boost the ammonia flowing through the supply line 45 to a pressure equal to or higher than that required by the engine. In addition, since it is no longer necessary to form a gas phase in the first pressurized tank 44, it is no longer necessary to adjust the liquid level. And, since the pressure of the first pressurized tank 44 can be adjusted by the low-pressure pump 42, it is possible to reduce the number of parts and simplify the configuration.

[0083] (Other embodiments) The present disclosure is not limited to the configurations of the above-described embodiments, and design changes are possible without departing from the spirit of the present disclosure. For example, in the above embodiment, the floating body 1 is described as a ship capable of navigating using a main engine or the like, but is not limited to a ship as long as the floating body is capable of storing ammonia.

[0084] In the first embodiment, the second pressure regulating valve 52 is provided in the first return line 47 between the second heat exchanger 51 and the first pressurized tank 44. However, the second pressure regulating valve 52 may not be provided, and the pressure in the first pressurized tank 44 may be set by the low pressure pump 42 to a pressure lower than the pressure of ammonia in the engine and capable of maintaining the ammonia in a liquid state. In this case, the first inert gas supply unit 55 and the low pressure pump 42 constitute the pressure maintaining unit in the present disclosure. When the second pressure regulating valve 52 is provided as in the first embodiment, the piping of the first return line 47 from the second pressure regulating valve 52 to the first pressurized tank 44 and the pressure resistance performance of the first pressurized tank 44 can be reduced, which is more advantageous in terms of cost reduction than when the second pressure regulating valve 52 is not provided.

[0085] <Additional Notes> The float described in the embodiment can be understood, for example, as follows.

[0086] (1) According to a first aspect, a float includes a float body, a fuel tank provided in the float body and storing ammonia, a first pressurized tank 44 in which the ammonia from the fuel tank is stored in a pressurized state, a supply line 45 through which the ammonia is discharged from the first pressurized tank 44, a boost pump 46 that boosts the pressure of the ammonia flowing through the supply line 45, an engine to which the ammonia is supplied as fuel via the supply line 45, a first return line 47 that returns the ammonia that has passed through the engine to the first pressurized tank 44, a first pressure regulating valve 48 provided in the first return line 47 and capable of adjusting the pressure of the ammonia in the engine, a cooling unit provided downstream of the first pressure regulating valve 48 in the first return line 47 and cooling the ammonia, and a pressure maintaining unit that maintains the pressure of the ammonia between the first pressure regulating valve 48 of the first return line 47 and the cooling unit at a pressure lower than the pressure of the ammonia in the engine and capable of maintaining the ammonia in a liquid state. Examples of the floating body 1 include ships such as liquefied gas carriers, ferries, RORO ships, car carriers, and passenger ships, FSUs (Floating Storage Units), and FSRUs (Floating Storage and Regasification Units).

[0087] This makes it possible to prevent ammonia from evaporating between the first pressure regulating valve 48 and the cooling part while arranging the cooling part downstream of the first pressure regulating valve 48, which has a low pressure. Therefore, it is possible to prevent trouble caused by erosion in the piping. In addition, since a cooling part with low pressure resistance can be used, it is possible to reduce costs.

[0088] (2) According to a second aspect, the float is a float of (1), wherein the pressure retaining section is provided with a second pressure regulating valve 52 provided between the cooling section of the first return line 47 and the first pressurized tank 44. This makes it possible to easily maintain the pressure of ammonia between the first pressure regulating valve 48 of the first return line 47 and the cooling section at a pressure that allows the ammonia to be maintained in a liquid state.

[0089] (3) According to a third aspect, the floating body is the floating body of (1) or (2), and includes a plurality of boost pumps 46 provided in series in the supply line 45. As a result, even if the ammonia pressure required by the engine differs depending on, for example, the manufacturer, the ammonia pressure can be boosted to the pressure required by the engine by adding the boost pump 46 in series. Furthermore, compared to a case where a single boost pump is used to boost the ammonia pressure to a pressure equal to or higher than the pressure required by the engine, an inexpensive boost pump can be used, which makes it possible to reduce costs.

[0090] (4) According to a fourth aspect, the float is any one of the floats (1) to (3), and the boost pump is a canned motor pump 146 that is provided in the supply line 45 to boost the ammonia discharged from the first pressurized tank 44 and uses a portion of the ammonia flowing through the supply line 45 as a coolant for a motor section, and is equipped with a first inert gas supply unit 55 that supplies an inert gas into the first pressurized tank 44, and a second return line 80 that returns the ammonia used as a coolant by the canned motor pump 146 to the gas phase of the first pressurized tank 44. This allows a gas phase to be formed in the first pressurized tank 44, making it possible to prevent air bubbles from being mixed into the liquid phase of ammonia. Furthermore, by supplying an inert gas into the first pressurized tank 44, it is possible to prevent the pressure in the first pressurized tank 44 from decreasing and the liquid ammonia from evaporating. Furthermore, it becomes unnecessary to return the ammonia used as the coolant to a tank such as a fuel tank that is installed in a location away from the canned motor pump 146 and has a gas phase. Therefore, even if the ammonia used as the coolant for the canned motor pump 146 is contaminated with oil or the like, it is possible to prevent the ammonia outside the fuel supply system of the engine from being contaminated.

[0091] (5) According to a fifth aspect, the float is a float as defined in (4), and is provided with a first liquid level detection unit 62 for detecting the liquid level in the first pressurized tank 44, and a first liquid level control valve for adjusting the flow rate of the ammonia supplied into the first pressurized tank 44. As a result, even if the flow rate of ammonia discharged from first pressurized tank 44 fluctuates due to engine load fluctuations, etc., the liquid level in first pressurized tank 44 can be easily maintained within a predetermined liquid level range.

[0092] (6) According to a sixth aspect, the float is any one of the floats (1) to (5), and includes a second pressurized tank 70 provided in the first return line 47 between the cooling section and the first pressurized tank 44 and capable of storing the ammonia flowing through the first return line 47, and a second inert gas supply section 71 that supplies an inert gas into the second pressurized tank 70. As a result, when purging ammonia from the fuel system for maintenance, fuel switching, or the like, liquid ammonia can be recovered by the second pressurized tank 70. Also, the amount of purge gas flowing into the first pressurized tank 44 can be reduced. Therefore, the capacity of the first pressurized tank 44 can be reduced. Therefore, the degree of freedom in arranging the first pressurized tank 44 can be improved.

[0093] (7) According to a seventh aspect, the float is a float as defined in (6), and is provided with a second liquid level detection unit 77 for detecting the liquid level in the second pressurized tank 70, and a second liquid level control valve for adjusting the flow rate of the ammonia discharged from the second pressurized tank 70 through the first return line 47. This makes it possible to easily maintain the liquid level in the second pressurized tank 70 within a predetermined liquid level range even if the flow rate of liquid ammonia flowing into the second pressurized tank 70 or the flow rate of liquid ammonia discharged from the second pressurized tank 70 fluctuates due to engine load fluctuations, etc.

[0094] (8) According to an eighth aspect, the float is the float of (1) or (2), and the boost pump 146 is a canned motor pump 146 that is provided in the supply line 45 and boosts the ammonia discharged from the first pressurized tank 44, and uses a portion of the ammonia flowing through the supply line 45 as a coolant for a motor section, and further includes a second pressurized tank 70 that is provided in the first return line 47 between the cooling section and the first pressurized tank 44 and is capable of storing the ammonia flowing through the first return line 47, a second inert gas supply section 71 that supplies an inert gas into the second pressurized tank 70, and a second pressurized tank return line 180 that returns a portion of the ammonia used as a coolant by the canned motor pump 146 to the gas phase of the second pressurized tank 70. This allows a portion of the ammonia used as a coolant in the canned motor pump 146 to be returned to the gas phase of the second pressurized tank 70.

[0095] (9) According to a ninth aspect, the float is the float of (8), wherein a portion of the ammonia used as a coolant in the canned motor pump 146 can be returned only to the gas phase of the second pressurized tank 70 via a second pressurized tank return line 180, and further includes a pressure detection unit 162 that detects the pressure in the first pressurized tank 44, and a pressure adjustment unit 42, 158 that adjusts the pressure in the first pressurized tank 44. This eliminates the need to form a gas phase in the first pressurized tank 44, and therefore the need to adjust the liquid level. In addition, since the pressure of the first pressurized tank 44 can be adjusted by the pressure adjustment units 42 and 158, the number of parts can be reduced and the configuration can be simplified.

[0096] (10) According to a tenth aspect, the float is the float of (8), further comprising a second return line 80 for returning a portion of the ammonia used as a coolant in the canned motor pump 146 to the first pressurized tank 44, and switching units 91, 92 for circulating a portion of the ammonia used as a coolant in the canned motor pump 146 to at least one of the second return line 80 and the second pressurized tank return line 180. This makes it possible to return a portion of the ammonia used as a coolant in the canned motor pump 146 to at least one of the first pressurized tank 44 and the second pressurized tank 70 in which a gas phase is formed. [Explanation of symbols]

[0097] 1,101,201...float 2...float body 4...superstructure 5A,5B...shipside 6...bottom of vessel 7...upper deck 8...combustion system 10...ammonia tank 20...ammonia fuel supply system 30...fuel supply system room 41...fuel tank outlet line 42...low pressure pump 43...first heat exchanger 44...first pressurized tank 45...supply line 46...booster pump 47...first return line 47A...upstream line 47B...downstream line 48...first pressure regulating valve 49...first pressure sensor 50...first flow rate sensor 51...second heat exchanger (cooling section) 52...second pressure regulating valve (pressure retention section) 53...second pressure sensor 54...first liquid level adjustment section 55...first inert gas supply section 56...first gas release section 57...fuel tank return line 58...flow rate adjustment valve 59...supply return line 60...Third pressure regulating valve 61...Third pressure sensor 62...First liquid level detection section 63...First liquid level regulating valve 70...Second pressurized tank 71...Second inert gas supply section 72...Second gas release section 73...Second liquid level regulating section 74...Bypass line 75...First switching valve 76...Second switching valve 77...Second liquid level detection section 78...Second liquid level regulating valve 80...Second return line 81...Third heat exchanger 85...Fifth heat exchanger 91...Third switching valve (switching section) 92...Fourth switching valve (switching section) 93...Sixth heat exchanger 94...Fifth switching valve 95...Sixth switching valve 96...Seventh heat exchanger 146...Canned motor pump 158...Fourth pressure regulating valve (pressure regulating section) 162...Fourth pressure sensor (pressure detection section) 180...Fourth return line (second pressurized tank return line) 246A...First canned motor pump 246B...Second canned motor pump 280...Third return line 281...Fourth heat exchanger 380...Fifth return line (second pressurized tank return line)

Claims

1. A floating body; a fuel tank provided on the floating body and storing ammonia; a first pressurized tank in which the ammonia from the fuel tank is stored under pressure; a supply line through which the ammonia is discharged from the first pressurized tank; a booster pump that boosts the pressure of the ammonia flowing through the supply line; an engine to which the ammonia is supplied as fuel via the supply line; a first return line returning the ammonia that has passed through the engine to the first pressurized tank; a first pressure regulating valve provided in the first return line and capable of adjusting the pressure of the ammonia in the engine; a cooling unit provided in the first return line downstream of the first pressure regulating valve and configured to cool the ammonia; a pressure maintaining unit that maintains a pressure of the ammonia between the first pressure regulating valve and the cooling unit in the first return line at a pressure that is lower than the pressure of the ammonia in the engine and that is capable of maintaining the ammonia in a liquid state; A floating body comprising:

2. The pressure maintaining unit includes a second pressure regulating valve provided between the cooling unit of the first return line and the first pressurized tank. The floating body according to claim 1.

3. a plurality of boost pumps provided in series in the supply line; 3. The floating body according to claim 1 or 2.

4. The boost pump is a canned motor pump that is provided in the supply line, increases the pressure of the ammonia discharged from the first pressurized tank, and uses a portion of the ammonia flowing through the supply line as a coolant for a motor unit, a first inert gas supply unit that supplies an inert gas into the first pressurized tank; a second return line for returning a portion of the ammonia used as a coolant in the canned motor pump to the gas phase of the first pressurized tank; Equipped with 3. The floating body according to claim 1 or 2.

5. a first liquid level detection unit that detects a liquid level in the first pressurized tank; a first liquid level control valve for adjusting the flow rate of the ammonia supplied into the first pressurized tank; Equipped with The floating body according to claim 4.

6. a second pressurized tank provided in the first return line between the cooling unit and the first pressurized tank and capable of storing the ammonia flowing through the first return line; a second inert gas supply unit that supplies an inert gas into the second pressurized tank; 3. The floating body according to claim 1 or 2.

7. a second liquid level detection unit that detects a liquid level in the second pressurized tank; a second liquid level control valve for adjusting the flow rate of the ammonia discharged from the second pressurized tank through the first return line; Equipped with The floating body according to claim 6.

8. The boost pump is a canned motor pump that is provided in the supply line, increases the pressure of the ammonia discharged from the first pressurized tank, and uses a portion of the ammonia flowing through the supply line as a coolant for a motor unit, a second pressurized tank provided in the first return line between the cooling unit and the first pressurized tank and capable of storing the ammonia flowing through the first return line; a second inert gas supply unit that supplies an inert gas into the second pressurized tank; a second pressurized tank return line for returning a portion of the ammonia used as a coolant in the canned motor pump to the gas phase of the second pressurized tank; Further provided with 3. The floating body according to claim 1 or 2.

9. a part of the ammonia used as a coolant in the canned motor pump can be returned only to the gas phase of the second pressurized tank through the second pressurized tank return line; a pressure detection unit that detects the pressure in the first pressurized tank; a pressure adjusting unit that adjusts the pressure in the first pressurized tank; Further provided with The floating body according to claim 8.

10. a second return line for returning a portion of the ammonia used as a coolant in the canned motor pump to the first pressurized tank; a switching unit that circulates a portion of the ammonia used as a coolant in the canned motor pump to at least one of the second return line and the second pressurized tank return line. The floating body according to claim 8.

11. Further comprising a flow sensor for detecting a flow rate of ammonia flowing through the first return line; The first pressure regulating valve is capable of adjusting a valve opening degree based on a detection result of the flow rate sensor so that the flow rate of the ammonia flowing through the first return line exceeds a predetermined lower limit value.

3. The floating body according to claim 1 or 2.

12. A first inert gas supply unit that supplies an inert gas into the first pressurized tank; a first gas discharge section that discharges gas in the gas phase of the first pressurized tank to the outside of the first pressurized tank.

3. The floating body according to claim 1 or 2.

13. A floating body, a fuel tank provided on the floating body and storing ammonia; a first pressurized tank in which the ammonia from the fuel tank is stored under pressure; a supply line through which the ammonia is discharged from the first pressurized tank; a booster pump that boosts the pressure of the ammonia flowing through the supply line; an engine to which the ammonia is supplied as fuel via the supply line; a first return line returning the ammonia that has passed through the engine to the first pressurized tank; a cooling section provided in the first return line to cool the ammonia; a second pressure regulating valve provided between the cooling portion of the first return line and the first pressurized tank, the second pressure regulating valve being capable of adjusting the pressure of the ammonia; A floating body comprising:

Images