Ship, method of generating electric power in a ship

Abstract

A ship includes a hull having a propeller, a main engine provided on the hull and driving the propeller, an axle generator driven by rotation of the main engine to generate a shipboard electric power, a tank provided on the hull and capable of storing a liquefied gas, a main supply line to gasify the liquefied gas stored in the tank and capable of supplying the main engine, and a boil-off gas line capable of supplying a boil-off gas generated in the tank to the main engine.

Description

Technical Field

[0001] This invention relates to a ship and a method for generating electricity on board.

[0002] This application claims priority based on Japanese Patent Application No. 2023-208378, filed on December 11, 2023, the contents of which are incorporated herein by reference. Background Technology

[0003] Patent Document 1 discloses a structure in which evaporated gas generated in a storage tank storing liquefied natural gas as fuel is compressed and reliquefied, and then supplied to an engine. This structure effectively utilizes the evaporated gas generated in the storage tank, thereby reducing fuel consumption.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 5926748 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] However, in ships as described in Patent Document 1, in order to generate electricity for use on board, in addition to the main engine, there is also an engine for driving a generator. Compared with the main engine, the engine used to drive the generator has low fuel consumption efficiency. Therefore, it is desirable to improve fuel consumption efficiency while effectively utilizing evaporated gas.

[0009] This invention was made to solve the above-mentioned problems, and its purpose is to provide a ship and a method for generating electricity on board that can effectively utilize evaporated gas to improve fuel consumption efficiency.

[0010] means for solving technical problems

[0011] To address the aforementioned issues, the vessel of the present invention comprises a hull, a main engine, a shaft generator, a storage tank, a main supply pipeline, and an evaporation gas pipeline. The hull has a propeller. The main engine is mounted on the hull and drives the propeller. The shaft generator is driven by the rotation of the main engine, thereby generating onboard electricity. The storage tank is mounted on the hull and is capable of storing liquefied petroleum gas (LPG). The main supply pipeline enables the LPG stored in the storage tank to be vaporized and supplied to the main engine. The evaporation gas pipeline enables the supply of evaporation gas generated in the storage tank to the main engine.

[0012] The shipboard power generation method involved in this invention is the shipboard power generation method described above. The shipboard power generation method switches between a first mode and a second mode. In the first mode, when the ship is sailing, evaporated gas is supplied to the main engine, and the shaft generator generates shipboard power. In the second mode, when the ship is moored, the evaporated gas is supplied to the auxiliary engine, and the auxiliary engine generates shipboard power.

[0013] Invention Effects

[0014] The ship and onboard power generation method according to the present invention can effectively utilize evaporated gas, thereby improving fuel consumption efficiency. Attached Figure Description

[0015] Figure 1 This is a side view of the ship involved in the embodiments of the present invention.

[0016] Figure 2 This is a diagram illustrating the fuel supply system from storage tanks to the main engine and auxiliary engines in a ship according to the first embodiment of the present invention.

[0017] Figure 3 This is a diagram illustrating the state of using a main engine to generate electricity in a ship according to an embodiment of the present invention.

[0018] Figure 4 This is a diagram illustrating the state of using auxiliary machinery to generate electricity in a ship according to an embodiment of the present invention.

[0019] Figure 5 This is a diagram illustrating the fuel supply system from storage tanks to the main engine and auxiliary engines in a ship according to the second embodiment of the present invention.

[0020] Figure 6 This is a diagram showing the flow of evaporated gas when the first mode is executed in the shipboard power generation method according to the second embodiment of the present invention.

[0021] Figure 7 This is a diagram showing the flow of evaporated gas when the second mode is executed in the shipboard power generation method according to the second embodiment of the present invention.

[0022] Figure 8 This is a diagram illustrating the fuel supply system from storage tanks to the main engine and auxiliary engines in a ship according to the third embodiment of the present invention.

[0023] Figure 9 This is a diagram showing the flow of evaporated gas when the first mode is executed in the shipboard power generation method according to the third embodiment of the present invention.

[0024] Figure 10This is a diagram showing the flow of evaporated gas when the second mode is executed in the shipboard power generation method according to the third embodiment of the present invention.

[0025] Figure 11 This is a diagram illustrating the fuel supply system from storage tanks to the main engine and auxiliary engines in a ship according to the fourth embodiment of the present invention.

[0026] Figure 12 This is a diagram showing the flow of evaporated gas when the first mode is executed in the shipboard power generation method according to the fourth embodiment of the present invention.

[0027] Figure 13 This is a diagram showing the flow of evaporated gas when the second mode is executed in the shipboard power generation method according to the fourth embodiment of the present invention.

[0028] Figure 14 This is a diagram illustrating the fuel supply system from storage tanks to the main engine and auxiliary engines in a ship according to the fifth embodiment of the present invention.

[0029] Figure 15 This is a diagram showing the flow of evaporated gas when the first mode is executed in the shipboard power generation method according to the fifth embodiment of the present invention.

[0030] Figure 16 This is a diagram showing the flow of evaporated gas when the second mode is executed in the shipboard power generation method according to the fifth embodiment of the present invention. Detailed Implementation

[0031] The following is for reference. Figures 1 to 16 The present invention will describe the ship and the shipboard power generation method involved in the embodiments of the present invention.

[0032] <First Implementation>

[0033] (The overall structure of the ship)

[0034] like Figure 1 As shown, the vessel 1 of this first embodiment mainly comprises a hull 2, a main engine 20, a shaft generator 25, auxiliary machinery 30, and a storage tank 10. The type of vessel 1 is not limited to a specific category. Examples of vessel types for vessel 1 include liquefied natural gas (LNG), carbon dioxide, ammonia, and other liquefied gas transport ships, ferries, RORO (Roll-on / Roll-off) vessels, PCTC (PureCar & Truck Carrier), passenger ships, etc.

[0035] The hull 2 ​​has a pair of side panels 3A and 3B that form its outer shell, a bottom 4, and an upper deck 5. The side panels 3A and 3B are formed by a pair of side panels that form the port and starboard sides respectively. The bottom 4 is formed by the bottom panels that connect these side panels 3A and 3B. The upper deck 5 is a full-length deck exposed to the outside. A superstructure 7 with a living area is formed on the upper deck 5 on the hull 2, for example, on the stern 2b side.

[0036] (Structure of main unit, shaft generator, and auxiliary equipment)

[0037] The main engine 20 and auxiliary engine 30 are housed within the hull 2. The main engine 20 and auxiliary engine 30 use liquefied petroleum gas (LPG) stored in the storage tank 10 as fuel. In this first embodiment, the main engine 20 and auxiliary engine 30 use LNG as fuel, for example. The LPG used as fuel for the main engine 20 and auxiliary engine 30 is not limited to LNG; it can also be LPG (liquefied petroleum gas), ammonia, hydrogen, etc.

[0038] The main engine 20 is, for example, an engine (internal combustion engine) that burns liquefied petroleum gas as fuel. In this first embodiment, the main engine 20 is a direct injection two-stroke engine that injects fuel directly into the combustion chamber. The main engine 20 uses fuel at a higher pressure than the auxiliary engine 30. The pressure of the fuel (fuel gas) used in the main engine 20 is, for example, a high pressure of 20 MPa or more and 35 MPa or less. The pressure of the fuel supplied to the main engine 20 is preferably, for example, 25 MPa or more and 30 MPa or less.

[0039] The main engine 20 drives the propeller 9. The propeller 9 is located outside the stern 2b of the hull 2. The main engine 20 and the propeller 9 are connected via a drive shaft 8 extending along the bow-stern direction FA. The main engine 20 drives the propeller 9 to rotate by rotating the drive shaft 8 about its axis. The propeller 9 provides propulsion for the ship 1 by rotating under the drive of the main engine 20.

[0040] A shaft generator 25 is installed inside the hull 2 ​​to generate internal power for use within the vessel 1. The shaft generator 25 is driven by the rotation of the main engine 20. In this first embodiment, the shaft generator 25 is connected to the drive shaft 8. The shaft generator 25 converts the rotational energy of the drive shaft 8, driven by the rotation of the main engine 20, into electrical energy. The shaft generator 25 can be directly connected to the drive shaft 8, or it can be connected to the drive shaft 8 via a speed increaser, clutch, or the like.

[0041] In the first embodiment of the present invention, the auxiliary engine 30 is an engine for a generator used to drive a generator (not shown) for generating onboard electricity for use within the ship 1. The auxiliary engine 30 uses fuel with a lower pressure than the main engine 20. The pressure of the fuel (fuel gas) used in the auxiliary engine 30 is, for example, 0.5 MPa or more and 1.0 MPa or less. As the auxiliary engine 30, for example, a gas turbine or a reciprocating engine can be used. The rotational energy generated by the auxiliary engine 30 is converted into electrical energy by the generator and can be supplied to various parts within the hull 2.

[0042] (Structure of the storage tank)

[0043] Storage tank 10 is installed on hull 2. In this first embodiment, storage tank 10 is installed, for example, on upper deck 5. Storage tank 10 may also be installed inside hull 2. In this first embodiment, storage tank 10 stores liquefied gas (LNG) as fuel for main engine 20 or auxiliary engine 30.

[0044] (Structure of main supply pipeline and evaporator pipeline)

[0045] Figure 2 This is a diagram illustrating the fuel supply system from storage tanks to the main engine and auxiliary engines in a ship according to the first embodiment of the present invention.

[0046] like Figure 2 As shown, the ship 1 is equipped with a main supply pipeline 100, an auxiliary engine supply pipeline 200 and an evaporative gas pipeline 300A in order to supply the liquefied gas stored in the storage tank 10 as fuel to the main engine 20 and the auxiliary engine 30.

[0047] The main supply line 100 connects the storage tank 10 and the main unit 20. The main supply line 100 vaporizes the liquefied gas LG in the storage tank 10 and supplies it to the main unit 20. A pump 11, a booster pump 12 and a high-pressure vaporizer 13 are installed on the main supply line 100.

[0048] Pump 11 is installed in the main supply pipeline 100. Pump 11 draws liquefied petroleum gas (LPG) LG from the storage tank 10. Pump 11 pressurizes and delivers the drawn-in LPG LG toward the main unit 20.

[0049] The booster pump 12 is located downstream of the liquefied gas LG in the main supply line 100, further downstream than the pump 11 in the flow direction of the main supply line 100. The booster pump 12 pressurizes the liquefied gas LG to a pressure higher than that of the pump 11.

[0050] The high-pressure vaporizer 13 is located downstream of the flow direction of the liquefied gas LG in the main supply line 100, further downstream than the pressurization pump 12. The high-pressure vaporizer 13 vaporizes the liquefied gas LG pressurized and supplied by the pressurization pump 12. The high-pressure vaporizer 13 vaporizes the liquefied gas LG at a higher pressure than the auxiliary vaporizer 31 described later to generate fuel gas FG. In this first embodiment, the pressure of the fuel gas FG generated by the pressure pump 12 and the high-pressure vaporizer 13 is, for example, about 30 MPa. The fuel gas FG generated by the high-pressure vaporizer 13 is supplied to the main unit 20 through the main supply line 100.

[0051] The auxiliary equipment supply pipeline 200 vaporizes the liquefied petroleum gas LG in the storage tank 10 and supplies it to the auxiliary equipment 30. The upstream end 201 of the auxiliary equipment supply pipeline 200 is connected to the pump 11 and the booster pump 12 in the main supply pipeline 100. The downstream end 202 of the auxiliary equipment supply pipeline 200 is connected to the auxiliary equipment 30.

[0052] The auxiliary equipment supply line 200 includes an auxiliary equipment vaporizer 31. The auxiliary equipment vaporizer 31 vaporizes the liquefied petroleum gas (LPG) LG that is pressurized and supplied by the pump 11. The auxiliary equipment vaporizer 31 vaporizes the LPG LG at a pressure lower than that of the high-pressure vaporizer 13 to generate auxiliary equipment fuel gas FG2. The pressure of the auxiliary equipment fuel gas FG2 generated by the pump 11 and the auxiliary equipment vaporizer 31 is, for example, about 0.6 MPa. The auxiliary equipment fuel gas FG2 generated by the auxiliary equipment vaporizer 31 is supplied to the auxiliary equipment 30 through the auxiliary equipment supply line 200.

[0053] The evaporation gas line 300A supplies the evaporation gas (BOG) generated in the storage tank 10 to the main unit 20. The upstream end 301 of the evaporation gas line 300A is connected to the storage tank 10 in a manner that communicates with the gas phase portion within the storage tank 10. The downstream end 302 of the evaporation gas line 300A is connected to the main supply line 100 on the downstream side of the high-pressure vaporizer 13.

[0054] Inside the storage tank 10, due to natural heat absorption from the outside, the liquid liquefied gas LG vaporizes, thereby generating evaporation gas BOG. ​​In this first embodiment, the evaporation gas pipeline 300A introduces the evaporation gas BOG generated inside the storage tank 10 into the main unit 20.

[0055] The evaporator gas line 300A includes a high-pressure gas compressor (gas compressor) 51 that pressurizes the evaporator gas supplied to the main unit 20 via the evaporator gas line 300A. The high-pressure gas compressor 51 can pressurize the evaporator gas BOG to a pressure higher than that of the fuel gas FG supplied to the main unit 20. In this first embodiment, the high-pressure gas compressor 51 pressurizes the evaporator gas BOG to a gaseous state with the same pressure as the fuel gas FG supplied via the pump 11, the pressurization pump 12, and the high-pressure vaporizer 13. The evaporator gas line 300A in this first embodiment allows the evaporator gas BOG pressurized by the high-pressure gas compressor 51 to merge with the main supply line 100 located downstream of the high-pressure vaporizer 13. That is, the evaporator gas line 300A supplies the evaporator gas BOG to the main unit 20 by mixing the evaporator gas BOG with the fuel gas FG vaporized in the high-pressure vaporizer 13.

[0056] (Methods for generating electricity on board ships)

[0057] Next, the method of generating electricity on board the aforementioned vessel 1 will be described.

[0058] Figure 3 This is a diagram showing the state of using a main engine to generate electricity in a ship according to the first embodiment of the present invention.

[0059] like Figure 3 As shown, in this first embodiment, when the ship 1 is navigating by the propeller 9 driven by the main engine 20, the main engine 20 drives the shaft generator 25, which generates onboard electricity. At this time, the evaporative gas BOG from the storage tank 10 is pressurized by the high-pressure gas compressor 51 and supplied to the main engine 20 via the evaporative gas pipeline 300A. Furthermore, depending on the amount of evaporative gas BOG generated in the storage tank 10, fuel gas FG (gas that vaporizes liquefied petroleum gas LG) can be supplied from the storage tank 10 to the main engine 20 via the main supply pipeline 100, passing through the pressurization pump 12 and the high-pressure vaporizer 13. Additionally, while the fuel gas FG from the main supply pipeline 100 is primarily supplied to the main engine 20, the insufficient amount can be compensated by the evaporative gas BOG supplied via the evaporative gas pipeline 300A.

[0060] In this first embodiment, when the main engine 20 drives the shaft generator 25, the auxiliary engine 30 is stopped. This is done by closing valve 205, which is installed in the auxiliary engine supply line 200, to stop the supply of liquefied petroleum gas (LPG) LG to the auxiliary engine 30. Thus, while the ship 1 is underway, it uses the main engine 20, which has a higher fuel consumption efficiency than the auxiliary engine 30, to generate onboard electricity from the shaft generator 25.

[0061] Figure 4 This is a diagram illustrating the state of using auxiliary machinery to generate electricity in a ship according to an embodiment of the present invention.

[0062] like Figure 4 As shown, during the period when the ship 1 is moored and the main engine 20 is stopped, the auxiliary engine 30 drives the generator (not shown) to supply power to the ship. For this purpose, liquefied petroleum gas (LPG) LG in the storage tank 10 is vaporized via the auxiliary engine supply line 200 and the auxiliary engine vaporizer 31, thereby generating auxiliary engine fuel gas FG. The auxiliary engine supply line 200 supplies the generated auxiliary engine fuel gas FG2 to the auxiliary engine 30.

[0063] In this case, for example, by closing valve 105 provided in the main supply line 100, liquefied gas LG is not supplied to the main engine 20. Furthermore, in the evaporation gas line 300A, for example, by closing valve 305 provided in the evaporation gas line 300A, evaporation gas BOG is also not supplied to the main engine 20. Additionally, in the first embodiment described above, the case where the auxiliary engine 30 is not driven during the navigation of the ship 1 was explained. However, in the state where only the shaft generator 25 is driven, if the ship's internal power is insufficient, the auxiliary engine 30 can be driven to compensate for the deficiency.

[0064] (Effects)

[0065] The vessel 1 of the first embodiment described above includes: a main supply pipeline 100 capable of supplying liquefied petroleum gas (LPG) LG from the storage tank 10 to the main engine 20; and an evaporative gas pipeline 300A capable of supplying evaporative gas BOG from the storage tank 10 to the main engine 20. Thus, the main engine 20 can use both the LPG LG from the storage tank 10 and the BOG generated within the storage tank 10 due to the vaporization of the LPG LG as fuel. When the propeller 9 is driven in such a main engine 20, the shaft generator 25 is driven along with the rotation of the main engine 20, thereby enabling the generation of onboard electricity using the fuel-efficient main engine 20. Therefore, the BOG can be effectively utilized and fuel consumption efficiency can be improved.

[0066] Furthermore, in the first embodiment described above, a high-pressure fuel gas, which becomes fuel for the main unit 20, is generated from liquefied petroleum gas LG in the storage tank 10 by a pressurizing pump 12 and a high-pressure vaporizer 13 installed in the main supply line 100. In the evaporation gas line 300A, the evaporation gas BOG is pressurized to the pressure of fuel gas supplied to the main unit 20 by a high-pressure gas compressor 51, and the evaporation gas BOG can be used as high-pressure fuel gas FG supplied to the main unit 20. Thus, when the main unit 20 requires high-pressure gas as fuel, the evaporation gas BOG can be effectively utilized and fuel consumption efficiency can be improved.

[0067] <Second Implementation>

[0068] Next, a second embodiment of the ship and the shipboard power generation method according to the present invention will be described. In the second embodiment described below, since the only difference from the first embodiment is the structure of the evaporation gas pipeline, the parts that are the same as those in the first embodiment will be labeled with the same symbols and repeated descriptions will be omitted.

[0069] Figure 5 This is a diagram illustrating the fuel supply system from storage tanks to the main engine and auxiliary engines in a ship according to the first embodiment of the present invention.

[0070] like Figure 5 As shown, the ship 1 of the second embodiment is equipped with a main supply pipeline 100, an auxiliary engine supply pipeline 200 and an evaporation gas pipeline 300B in order to supply the liquefied gas stored in the storage tank 10 as fuel to the main engine 20 and the auxiliary engine 30.

[0071] The evaporation gas line 300B supplies the evaporation gas (BOG) generated in the storage tank 10 to the main unit 20. The upstream end 301 of the evaporation gas line 300B is connected to the storage tank 10 in a manner that communicates with the gas phase portion within the storage tank 10. The downstream end 302 of the evaporation gas line 300B is connected to the main supply line 100 on the downstream side relative to the high-pressure vaporizer 13.

[0072] The evaporator gas line 300B includes a gas compressor 52 that pressurizes the evaporator gas BOG supplied to the main unit 20 via the evaporator gas line 300B. The gas compressor 52 is capable of pressurizing the evaporator gas BOG to a pressure higher than that of the fuel gas FG supplied to the main unit 20. In this second embodiment, the evaporator gas line 300B includes a first gas compressor 53 and a second gas compressor 54 as a plurality of gas compressors 52.

[0073] The first gas compressor 53 pressurizes the evaporating gas BOG supplied from the storage tank 10 through the evaporating gas line 300B to a first pressure (e.g., 0.6 MPa) required to serve as fuel for the auxiliary machine 30 (the pressure of the auxiliary machine fuel gas FG2).

[0074] A second gas compressor 54 is disposed in the evaporator gas line 300B between the first gas compressor 53 and the main supply line 100 connected to the downstream end 302. The second gas compressor 54 further pressurizes the evaporator gas BOG, which has been pressurized to a first pressure by the first gas compressor 53, to a second pressure (e.g., 30 MPa) required as fuel for the main unit 20. This second pressure is preferably set to the equivalent pressure of the fuel gas FG after passing through the pump 11, the booster pump 12, and the high-pressure vaporizer 13.

[0075] Here, the second gas compressor 54 only needs to pressurize the evaporated gas BOG, which has been pressurized to the first pressure by the first gas compressor 53, to the second pressure. Therefore, its capacity is lower than that of the high-pressure gas compressor 51 shown in the first embodiment above.

[0076] Evaporation gas line 300B allows evaporation gas BOG, which has been pressurized by the first gas compressor 53 and the second gas compressor 54, to flow into the main supply line 100 downstream of the high-pressure vaporizer 13. That is, evaporation gas line 300B supplies the main unit 20 by mixing the evaporation gas BOG with the fuel gas FG vaporized in the high-pressure vaporizer 13.

[0077] Furthermore, an auxiliary machine evaporator gas supply line 400 is branched onto the evaporator gas line 300B. The upstream end of the auxiliary machine evaporator gas supply line 400 is connected to the evaporator gas line 300B between the first gas compressor 53 and the second gas compressor 54. The downstream end of the auxiliary machine evaporator gas supply line 400 is connected to the auxiliary machine 30. This auxiliary machine evaporator gas supply line 400 supplies the evaporator gas BOG, which has been pressurized to a first pressure by the first gas compressor 53, to the auxiliary machine 30 as auxiliary machine fuel gas FG2.

[0078] (Structure of the switching unit)

[0079] The vessel 1 of this second embodiment includes a switching unit 70. The switching unit 70 is capable of selectively switching the supply destination of the evaporative gas (BOG) based on the evaporative gas pipeline 300B between the main engine 20 and the auxiliary engine 30. The switching unit 70 includes a first valve 71 and a second valve 72.

[0080] A first valve 71 is disposed in the evaporator gas line 300B between the first gas compressor 53 and the second gas compressor 54. The first valve 71 is disposed in the evaporator gas line 300B at a position further downstream than the upstream end of the auxiliary machine evaporator gas supply line 400. The first valve 71 can open or close the flow path in the evaporator gas line 300B.

[0081] The second valve 72 is located midway in the auxiliary machine evaporator gas supply line 400. The second valve 72 can open or close the flow path within the auxiliary machine evaporator gas supply line 400.

[0082] With the first valve 71 open and the second valve 72 closed, the evaporative gas BOG is pressurized to a second pressure by the first gas compressor 53 and the second gas compressor 54 and supplied to the main unit 20. Conversely, with the first valve 71 closed and the second valve 72 open, the evaporative gas BOG is pressurized to a first pressure only by the first gas compressor 53 and supplied to the auxiliary unit 30 as auxiliary fuel gas FG2.

[0083] The first valve 71 and the second valve 72 can be opened and closed by manual operation or remote operation of the operator.

[0084] (Methods for generating electricity on board ships)

[0085] Next, the method for generating electricity onboard the vessel 1 as described above will be explained.

[0086] Figure 6 This is a diagram showing the flow of evaporated gas when the first mode is executed in the shipboard power generation method according to the second embodiment of the present invention. Figure 7 This is a diagram showing the flow of evaporated gas when the first mode is executed in the shipboard power generation method according to the second embodiment of the present invention.

[0087] Ship 1 switches the destination of evaporative air (BOG) supply between the main engine 20 and the auxiliary engine 30, depending on its navigation status, specifically, whether the main engine 20 is operating. Therefore, ship 1 is configured to switch between a first mode M1 executed during navigation and a second mode M2 ​​executed while at anchor.

[0088] like Figure 6 As shown, in this second embodiment, when the ship 1 is sailing by driving the propeller 9 via the main engine 20, a first mode M1 is executed within the ship 1. In the first mode M1, the main engine 20 drives the shaft generator 25, and the shaft generator 25 generates internal power. In this case, the first valve 71 is opened and the second valve 72 is closed. As a result, the vaporized gas BOG from the storage tank 10 is pressurized to a second pressure by the first gas compressor 53 and the second gas compressor 54, and then supplied to the main engine 20. In this first mode M1, when the ship 1 is sailing, the vaporized gas BOG is supplied to the main engine 20, and the shaft generator 25 generates internal power.

[0089] At this time, fuel gas FG (gas that vaporizes liquefied gas LG) that has passed through the pressurization pump 12 and the high-pressure vaporizer 13 can also be supplied from the storage tank 10 to the main unit 20 through the main supply pipeline 100, based on the amount of evaporative gas BOG generated in the storage tank 10 and the insufficient supply capacity of the second gas compressor 54 relative to the amount of fuel gas required by the main unit 20.

[0090] like Figure 7As shown, in this second embodiment, when the ship 1 is docked and the propeller 9 is not driven by the main engine 20, the ship 1 operates in second mode M2. In second mode M2, the first valve 71 is closed and the second valve 72 is opened. As a result, the vaporized gas BOG from the storage tank 10 is pressurized to a first pressure only by the first gas compressor 53, and supplied to the auxiliary engine 30 as auxiliary engine fuel gas FG2 through the auxiliary engine vaporized gas supply line 400. In this second mode M2, when the ship 1 is docked, the vaporized gas BOG is supplied to the auxiliary engine 30, which generates onboard electricity.

[0091] At this time, based on the amount of vaporized gas BOG generated in the storage tank 10 and the insufficient supply capacity of the first gas compressor 53 relative to the fuel gas required by the auxiliary machine 30, fuel gas FG (the gas that vaporizes liquefied gas LG) generated by the pump 11 and the auxiliary machine vaporizer 31 can be supplied from the storage tank 10 to the auxiliary machine 30 via the auxiliary machine supply pipeline 200. Furthermore, in the second embodiment described above, the case where the auxiliary machine 30 is not driven during the navigation of the ship 1 was explained. However, similarly to the first embodiment, when the ship's internal power is insufficient while only the shaft generator 25 is running, liquefied gas BOG can be supplied from the first gas compressor 53 to both the auxiliary machine 30 and the second gas compressor 54, and the auxiliary machine 30 can be driven to compensate for the insufficient internal power.

[0092] (Effects)

[0093] The vessel 1 of the second embodiment described above can selectively switch the supply destination of evaporative air BOG based on the evaporative air pipeline 300B between the main engine 20 and the auxiliary engine 30 via the switching unit 70. Thus, when the main engine 20 is operating, evaporative air BOG can be supplied to the main engine 20, and when the auxiliary engine 30 is operating, evaporative air BOG can be supplied to the auxiliary engine 30. Therefore, the waste of evaporative air BOG generated in the storage tank 10 can be suppressed, and the evaporative air BOG can be effectively consumed in both the main engine 20 and the auxiliary engine 30.

[0094] Furthermore, in the second embodiment described above, a high-pressure fuel gas, which becomes fuel for the main unit 20, is generated from liquefied petroleum gas LG in the storage tank 10 by a pressurizing pump 12 and a high-pressure vaporizer 13 installed in the main supply line 100. In the evaporation gas line 300B, the evaporation gas BOG is pressurized to the pressure of fuel gas supplied to the main unit 20 by a gas compressor 52, allowing the evaporation gas BOG to be used as high-pressure fuel gas supplied to the main unit 20. Thus, when the main unit 20 requires high-pressure gas as fuel, the evaporation gas BOG can be effectively utilized, improving fuel consumption efficiency.

[0095] Furthermore, in the second embodiment described above, the gas compressor 52 includes a first gas compressor 53 and a second gas compressor 54. By pressurizing the evaporative gas BOG to a first pressure in the first gas compressor 53, the pressurized evaporative gas BOG can be supplied to the auxiliary machine 30 as auxiliary fuel gas FG2. Furthermore, by further pressurizing the evaporative gas, which has been pressurized to the first pressure by the first gas compressor 53, to a second pressure in the second gas compressor 54, the pressurized evaporative gas BOG can be supplied to the main machine 20 as fuel gas FG. Thus, when supplying evaporative gas BOG to the main machine 20, the evaporative gas BOG is pressurized in two stages in both the first gas compressor 53 and the second gas compressor 54; when supplying evaporative gas BOG to the auxiliary machine 30, the evaporative gas BOG is pressurized only in the first gas compressor 53. With this evaporative gas pipeline 300B, a structure can be achieved where the supply destination of the evaporative gas BOG can be switched between the main machine 20 and the auxiliary machine 30.

[0096] In the ship's internal power generation method of the second embodiment described above, two modes are switched: a first mode M1, in which evaporative gas (BOG) is supplied to the main engine 20 when the ship 1 is sailing, and the shaft generator 25 generates internal ship power; and a second mode M2, in which evaporative gas (BOG) is supplied to the auxiliary engine 30 when the ship 1 is docked, and the auxiliary engine 30 generates internal ship power. Thus, when the main engine 20 is operating while the ship 1 is sailing, internal ship power can be generated in the main engine 20, and when the auxiliary engine 30 is operating while the ship 1 is docked, internal ship power can be generated in the auxiliary engine 30. Therefore, the evaporative gas (BOG) wasted in the storage tank 10 can be suppressed, and it can be effectively utilized to generate internal ship power through the main engine 20 and the auxiliary engine 30. As a result, even when the main engine 20 requires high-pressure gas as fuel, evaporative gas can be effectively utilized to improve fuel consumption efficiency.

[0097] Furthermore, similar to the first embodiment described above, the second embodiment includes a main supply line 100 capable of supplying liquefied petroleum gas (LPG) from the storage tank 10 to the main unit 20, and an evaporation gas line 300B capable of supplying evaporation gas (BOG) from the storage tank 10 to the main unit 20. This allows for efficient utilization of the evaporation gas (BOG) and improved fuel consumption efficiency.

[0098] Furthermore, in the second embodiment described above, a high-pressure fuel gas FG, which becomes fuel for the main unit 20, is generated from liquefied petroleum gas LG in the storage tank 10 by a pressurizing pump 12 and a high-pressure vaporizer 13 installed in the main supply line 100. In the evaporation gas line 300B, the evaporation gas BOG is pressurized to a pressure corresponding to the fuel gas FG supplied to the main unit 20 by a high-pressure gas compressor 51, so that the evaporation gas BOG can be used as the high-pressure fuel gas FG supplied to the main unit 20. Thus, when the main unit 20 requires high-pressure gas as fuel, the evaporation gas can be effectively utilized to improve fuel consumption efficiency.

[0099] Furthermore, in the second embodiment described above, the switching unit 70 includes a first valve 71 and a second valve 72, but is not limited thereto.

[0100] The operation / stop of the second gas compressor 54 can also be switched instead of the first valve 71, which serves as the switching unit 70, thereby switching the supply / stop of evaporative gas BOG through the evaporative gas pipeline 300B. That is, when shipboard power is generated by the shaft generator 25, the second gas compressor 54 is operated, and evaporative gas BOG from the storage tank 10 is supplied to the main engine 20 via the first gas compressor 53 and the second gas compressor 54. And, when shipboard power is generated by the auxiliary machine 30, the operation of the second gas compressor 54 is stopped. Thus, evaporative gas BOG from the storage tank 10 is supplied to the auxiliary machine 30 as auxiliary fuel gas FG2 only through the first gas compressor 53.

[0101] <Third Implementation Method>

[0102] Next, a third embodiment of the ship and the shipboard power generation method according to the present invention will be described. In the third embodiment described below, since the only difference from the first embodiment is the structure of the evaporation gas pipeline, the parts that are the same as those in the first and second embodiments will be labeled with the same symbols and repeated descriptions will be omitted.

[0103] Figure 8 This is a diagram illustrating the fuel supply system from storage tanks to the main engine and auxiliary engines in a ship according to the third embodiment of the present invention.

[0104] like Figure 8 As shown, the ship 1 of the third embodiment is equipped with a main supply pipeline 100, an auxiliary engine supply pipeline 200 and an evaporative gas pipeline 300C in order to supply the liquefied gas stored in the storage tank 10 as fuel to the main engine 20 and the auxiliary engine 30.

[0105] The evaporative gas pipeline 300C supplies the evaporative gas (BOG) generated in the storage tank 10 to the main unit 20. The upstream end 301 of the evaporative gas pipeline 300C is connected to the storage tank 10 in communication with the gas phase portion within the storage tank 10. The downstream end 303 of the evaporative gas pipeline 300C is connected to the main supply pipeline 100 between the pump 11 and the booster pump 12. The downstream end 303 of the evaporative gas pipeline 300C is connected to the main supply pipeline 100 at a position further downstream than the upstream end 201 of the auxiliary supply pipeline 200.

[0106] The evaporation gas line 300C is equipped with a gas compressor 55 that pressurizes the evaporation gas supplied to the main unit 20 through the evaporation gas line 300C. In this third embodiment, the gas compressor 55 pressurizes the evaporation gas BOG supplied from the storage tank 10 through the evaporation gas line 300C to the pressure required for fuel (auxiliary fuel gas FG2) of the auxiliary unit 30 (e.g., 0.6 MPa).

[0107] The evaporative gas line 300C mixes the evaporative gas BOG, pressurized by the gas compressor 55, with the liquefied gas LG flowing in the main supply line 100. In this third embodiment, the evaporative gas line 300C mixes the evaporative gas BOG, pressurized by the gas compressor 55, with the liquefied gas LG flowing in the main supply line 100 upstream of the pressurization pump 12. As a result, the evaporative gas BOG mixed in the liquefied gas LG is cooled by the liquefied gas LG, thus promoting the reliquefaction of the evaporative gas BOG. ​​Therefore, the evaporative gas BOG, pressurized by the gas compressor 55, together with the liquefied gas LG from the storage tank 10, is further pressurized by the pressurization pump 12, vaporized in the high-pressure vaporizer 13, and sent to the main unit 20.

[0108] Furthermore, an auxiliary machine evaporator gas supply line 400 is connected to the evaporator gas line 300C. The upstream end of the auxiliary machine evaporator gas supply line 400 is connected to the evaporator gas line 300C between the gas compressor 55 and the downstream end 303 of the evaporator gas line 300C. The downstream end of the auxiliary machine evaporator gas supply line 400 is connected to the auxiliary machine 30. This auxiliary machine evaporator gas supply line 400 supplies the evaporator gas BOG, which has been pressurized by the gas compressor 55, to the auxiliary machine 30 as auxiliary machine fuel gas FG2.

[0109] (Structure of the switching unit)

[0110] The vessel 1 of the third embodiment includes a switching unit 70B. The switching unit 70B is capable of selectively switching the supply destination of the evaporative gas (BOG) based on the evaporative gas pipeline 300C between the main engine 20 and the auxiliary engine 30. The switching unit 70B includes a first valve 73 and a second valve 74.

[0111] A first valve 73 is disposed in the evaporator gas line 300C between the gas compressor 55 and the downstream end 303 of the evaporator gas line 300C. The first valve 73 is disposed in the evaporator gas line 300C further downstream than the upstream end of the auxiliary machine evaporator gas supply line 400. The first valve 73 can open or close the flow path in the evaporator gas line 300C.

[0112] The second valve 74 is located midway in the auxiliary machine evaporator gas supply line 400. The second valve 74 can open or close the flow path within the auxiliary machine evaporator gas supply line 400.

[0113] With the first valve 73 open and the second valve 74 closed, the evaporative gas BOG is pressurized via the gas compressor 55, the pressurization pump 12, and the high-pressure vaporizer 13, and supplied to the main unit 20 as fuel gas FG. Furthermore, with the first valve 73 closed and the second valve 74 open, the evaporative gas BOG is pressurized only via the gas compressor 55 and supplied to the auxiliary unit 30 as auxiliary fuel gas FG2.

[0114] (Methods for generating electricity on board ships)

[0115] Next, the method for generating electricity onboard the vessel 1 as described above will be explained.

[0116] Figure 9 This is a diagram showing the flow of evaporated gas when the first mode is executed in the shipboard power generation method according to the second embodiment of the present invention. Figure 10 This is a diagram showing the flow of evaporated gas when the second mode is executed in the shipboard power generation method according to the third embodiment of the present invention.

[0117] like Figure 9 As shown, when the vessel 1 is sailing by driving the propeller 9 via the main engine 20, the first mode M11 is executed within the vessel 1. In the first mode M11, the main engine 20 drives the shaft generator 25, which generates onboard electricity. In this case, the first valve 73 is opened and the second valve 74 is closed. Thus, the vaporized gas BOG from the storage tank 10 is supplied to the main engine 20 as fuel gas FG via the gas compressor 55, the pressurization pump 12, and the high-pressure vaporizer 13. In the first mode M11, while the vessel 1 is sailing, the vaporized gas BOG is supplied to the main engine 20, and the shaft generator 25 generates onboard electricity.

[0118] like Figure 10As shown, when the vessel 1 is anchored and the propeller 9 is not driven by the main engine 20, the second mode M12 is executed on the vessel 1. In the second mode M12, the first valve 73 is closed and the second valve 74 is opened. As a result, the vaporized gas BOG from the storage tank 10 is pressurized only by the gas compressor 55 and supplied to the auxiliary engine 30 as auxiliary engine fuel gas FG2 through the auxiliary engine vaporized gas supply line 400. In the second mode M12, when the vessel 1 is anchored, the vaporized gas BOG is supplied to the auxiliary engine 30, which generates onboard electricity.

[0119] (Effects)

[0120] In the third embodiment described above, the ship 1 generates high-pressure fuel gas, which becomes fuel for the main engine 20, from liquefied petroleum gas (LPG) in the storage tank 10 via a pressurizing pump 12 and a high-pressure vaporizer 13 installed in the main supply line 100. By mixing vaporized gas BOG with the pressurized LPG flowing in the main supply line 100, it can be supplied as fuel for the main engine 20. Thus, by vaporizing vaporized gas BOG together with LPG flowing in the main supply line 100, fuel gas FG can be efficiently generated and supplied to the main engine 20.

[0121] Furthermore, similar to the second embodiment described above, in the third embodiment, the destination of the evaporative gas BOG supplied based on the evaporative gas pipeline 300C can be selectively switched between the main unit 20 and the auxiliary unit 30 via the switching unit 70B. Therefore, when the main unit 20 is operating, evaporative gas BOG can be supplied to the main unit 20, and when the auxiliary unit 30 is operating, evaporative gas BOG can be supplied to the auxiliary unit 30. Thus, the waste of evaporative gas BOG generated in the storage tank 10 can be suppressed, and the evaporative gas BOG can be effectively consumed in both the main unit 20 and the auxiliary unit 30.

[0122] In the ship's internal power generation method of the third embodiment described above, two modes are switched: a first mode M11, in which evaporative air gas (BOG) is supplied to the main engine 20 when the ship 1 is sailing, and the shaft generator 25 generates internal ship power; and a second mode M12, in which evaporative air gas (BOG) is supplied to the auxiliary engine 30 when the ship 1 is docked, and the auxiliary engine 30 generates internal ship power. Thus, when the main engine 20 is running while the ship 1 is sailing, internal ship power can be generated in the main engine 20, and when the auxiliary engine 30 is running while the ship 1 is docked, internal ship power can be generated in the auxiliary engine 30. Therefore, the evaporative air gas (BOG) wasted in the storage tank 10 can be suppressed, and it can be effectively utilized to generate internal ship power through the main engine 20 and the auxiliary engine 30. As a result, fuel consumption efficiency can be improved by effectively utilizing evaporative air.

[0123] Furthermore, similar to the first embodiment described above, the third embodiment includes a main supply line 100 capable of supplying liquefied petroleum gas (LPG) from the storage tank 10 to the main unit 20, and an evaporation gas line 300C capable of supplying evaporation gas (BOG) from the storage tank 10 to the main unit 20. This allows for efficient utilization of the evaporation gas (BOG) and improved fuel consumption efficiency.

[0124] <Fourth Implementation>

[0125] Next, a fourth embodiment of the ship and the ship's internal power generation method according to the present invention will be described. In the fourth embodiment described below, since the only difference from the first to third embodiments is the structure of the evaporation gas pipeline, the parts that are the same as those in the first to third embodiments will be labeled with the same symbols and repeated descriptions will be omitted.

[0126] Figure 11 This is a diagram illustrating the fuel supply system from storage tanks to the main engine and auxiliary engines in a ship according to the fourth embodiment of the present invention.

[0127] like Figure 11 As shown, the ship 1 of the fourth embodiment is equipped with a main supply pipeline 100, an auxiliary engine supply pipeline 200 and an evaporation gas pipeline 300D in order to supply the liquefied gas stored in the storage tank 10 as fuel to the main engine 20 and the auxiliary engine 30.

[0128] The evaporative gas pipeline 300D supplies the evaporative gas (BOG) generated in the storage tank 10 to the main unit 20. The upstream end 301 of the evaporative gas pipeline 300D is connected to the storage tank 10. The downstream end 304 of the evaporative gas pipeline 300D is connected to the main supply pipeline 100 between the pump 11 and the booster pump 12. The downstream end 304 of the evaporative gas pipeline 300D is connected to the main supply pipeline 100 on the downstream side relative to the upstream end 201 of the auxiliary supply pipeline 200.

[0129] A gas compressor 55 and a heat exchanger 56 are installed on the evaporation gas pipeline 300D. The gas compressor 55 pressurizes the evaporation gas BOG supplied to the main unit 20 through the evaporation gas pipeline 300D. The heat exchanger 56 is installed in the main supply pipeline 100 between the pressurization pump 12 and the high-pressure vaporizer 13. The heat exchanger 56 performs heat exchange between the evaporation gas BOG flowing through the evaporation gas pipeline 300D and the liquefied gas LG passing through the pressurization pump 12 in the main supply pipeline 100.

[0130] Evaporation gas line 300D allows evaporation gas BOG, pressurized by gas compressor 55, to exchange heat with liquefied gas LG in heat exchanger 56 for cooling, and then mixes it with liquefied gas LG flowing in main supply line 100. In an embodiment of the invention, evaporation gas line 300D allows evaporation gas BOG, pressurized by gas compressor 55, to mix with liquefied gas LG flowing in main supply line 100 upstream of pressurization pump 12. Thus, the evaporation gas BOG, pressurized and cooled by gas compressor 55 and heat exchanger 56, together with liquefied gas LG from storage tank 10, is further pressurized by pressurization pump 12, vaporized by high-pressure vaporizer 13, and sent to main unit 20.

[0131] (Methods for generating electricity on board ships)

[0132] Next, the method for generating electricity onboard the vessel 1 as described above will be explained.

[0133] Figure 12 This is a diagram showing the flow of evaporated gas when the first mode is executed in the shipboard power generation method according to the fourth embodiment of the present invention. Figure 13 This is a diagram showing the flow of evaporated gas when the first mode is executed in the shipboard power generation method according to the fourth embodiment of the present invention.

[0134] like Figure 12 As shown, when the vessel 1 is sailing by driving the propeller 9 via the main engine 20, the first mode M21 is executed within the vessel 1. In the first mode M21, the main engine 20 drives the shaft generator 25, which generates onboard electricity. In this case, the first valve 73 is opened and the second valve 74 is closed. Thus, the vaporized gas BOG from the storage tank 10 is supplied to the main engine 20 as fuel gas FG after passing through the gas compressor 55, heat exchanger 56, pressurization pump 12, and high-pressure vaporizer 13. In the first mode M21, the vaporized gas BOG generated during the vessel 1's navigation is supplied to the main engine 20, and the shaft generator 25 generates onboard electricity.

[0135] like Figure 13 As shown, when vessel 1 is moored and propeller 9 is not driven by main engine 20, second mode M22 is executed on vessel 1. In second mode M22, the vaporized gas BOG from storage tank 10 is pressurized only by gas compressor 55 and supplied to auxiliary engine 30 as auxiliary engine fuel gas FG2 through auxiliary engine vaporized gas supply line 400. In second mode M22, the vaporized gas BOG generated when vessel 1 is moored is supplied to auxiliary engine 30, and auxiliary engine 30 generates onboard electricity.

[0136] (Effects)

[0137] The ship 1 of the fourth embodiment described above is equipped with a heat exchanger 56. In the heat exchanger 56, the evaporated gas BOG flowing in the evaporated gas line 300D exchanges heat with the liquefied gas LG that has passed through the pressurization pump 12, thereby cooling the evaporated gas BOG. ​​By mixing the evaporated gas BOG cooled in the heat exchanger 56 with the liquefied gas LG flowing in the main supply line 100, the amount of reliquefiable evaporated gas BOG is increased, and the evaporated gas BOG can be consumed effectively.

[0138] Furthermore, in the fourth embodiment described above, similarly to the third embodiment, by mixing the evaporated gas BOG with the pressurized liquefied gas LG flowing in the main supply line 100, the pressure of the evaporated gas BOG increases, making it easier to vaporize when supplied as fuel to the main unit 20. Thus, by vaporizing the evaporated gas BOG together with the liquefied gas LG flowing in the main supply line 100, fuel gas FG can be efficiently generated and supplied to the main unit 20.

[0139] Furthermore, similar to the first embodiment described above, the fourth embodiment includes a main supply line 100 capable of supplying liquefied petroleum gas (LPG) from the storage tank 10 to the main unit 20, and an evaporation gas line 300D capable of supplying evaporation gas (BOG) from the storage tank 10 to the main unit 20. This allows for efficient utilization of the evaporation gas (BOG) and improved fuel consumption efficiency.

[0140] <Fifth Implementation>

[0141] Next, a fifth embodiment of the ship and the ship's internal power generation method according to the present invention will be described. In the fifth embodiment described below, since the only difference from the first to fourth embodiments is the structure of the evaporation gas pipeline, the parts that are the same as those in the first to fourth embodiments will be labeled with the same symbols and repeated descriptions will be omitted.

[0142] Figure 14 This is a diagram illustrating the fuel supply system from storage tanks to the main engine and auxiliary engines in a ship according to the fifth embodiment of the present invention.

[0143] like Figure 14 As shown, the ship 1 of the fifth embodiment is equipped with a main supply pipeline 100, an auxiliary engine supply pipeline 200 and an evaporation gas pipeline 300E in order to supply the liquefied gas stored in the storage tank 10 as fuel to the main engine 20 and the auxiliary engine 30.

[0144] The evaporation gas pipeline 300E can supply the evaporation gas BOG generated in the storage tank 10 to the main unit 20. The upstream end 301 of the evaporation gas pipeline 300E is connected to the storage tank 10.

[0145] The evaporative gas line 300E branches into a first line 310 and a second line 320 midway. The downstream end 312 of the first line 310 is connected to the main supply line 100 on the downstream side relative to the high-pressure vaporizer 13.

[0146] The downstream end 322 of the second pipeline 320 is connected to the main supply pipeline 100 between pump 11 and booster pump 12. The downstream end 322 of the second pipeline 320 is connected to the main supply pipeline 100 on the downstream side relative to the upstream end 201 of the auxiliary machine supply pipeline 200.

[0147] A first gas compressor 53 and a second gas compressor 54, which serve as gas compressors 52, and a heat exchanger 56 are installed on the evaporation gas pipeline 300E.

[0148] A first gas compressor 53 is disposed in the evaporation gas line 300E between the storage tank 10 and the second gas compressor 54. The first gas compressor 53 pressurizes the evaporation gas BOG supplied from the storage tank 10 through the evaporation gas line 300E to a first pressure (e.g., 0.6 MPa) required to serve as fuel for the auxiliary machine 30 (the pressure of the auxiliary machine fuel gas FG2).

[0149] A second gas compressor 54 is disposed in the middle of the first line 310 in the evaporator gas line 300E. The second gas compressor 54 further pressurizes the evaporator gas BOG, which has been pressurized to a first pressure by the first gas compressor 53, to a second pressure (e.g., 30 MPa) required to serve as fuel for the main unit 20. The evaporator gas line 300E mixes the evaporator gas BOG, which has been pressurized by the first gas compressor 53 and the second gas compressor 54, with the main supply line 100 on the downstream side relative to the high-pressure vaporizer 13. In the main supply line 100, the evaporator gas line 300E mixes the evaporator gas BOG with the fuel gas FG vaporized in the high-pressure vaporizer 13, and a portion of the evaporator gas BOG supplied to the main unit 20 is also supplied by the evaporator gas line 300E.

[0150] Heat exchanger 56 is located midway through the second pipeline 320. Heat exchanger 56 exchanges heat between the evaporating gas BOG, which flows in the evaporating gas pipeline 300E and is pressurized by the first gas compressor 53, and the gas LG, which is liquefied by the pressurization pump 12 of the main supply pipeline 100.

[0151] Evaporation gas line 300E mixes a portion of the evaporation gas BOG, which has been cooled by heat exchange with liquefied gas LG via heat exchanger 56 and pressurized by the first gas compressor 53, with the liquefied gas LG flowing in the main supply line 100. In the fifth embodiment, evaporation gas line 300E mixes the evaporation gas BOG, which has been pressurized by the first gas compressor 53, with the liquefied gas LG flowing in the main supply line 100 upstream of the pressurization pump 12. Thus, the evaporation gas BOG, which has been pressurized and cooled by the first gas compressor 53 and heat exchanger 56, together with the liquefied gas LG from the storage tank 10, is further pressurized by the pressurization pump 12, vaporized by the high-pressure vaporizer 13, and sent to the main unit 20.

[0152] Additionally, each of the first pipeline 310 and the second pipeline 320 can be equipped with an on / off valve, a flow regulating valve, etc., to balance the flow rates of the evaporative gas BOG supplied to the second gas compressor 54 and the evaporative gas BOG supplied to the heat exchanger 56. Furthermore, the heat exchanger 56 in this fifth embodiment can be omitted.

[0153] (Methods for generating electricity on board ships)

[0154] Next, the method for generating electricity onboard the vessel 1 as described above will be explained.

[0155] Figure 15 This is a diagram showing the flow of evaporated gas when the first mode is executed in the shipboard power generation method according to the fifth embodiment of the present invention. Figure 16 This is a diagram showing the flow of evaporated gas when the second mode is executed in the shipboard power generation method according to the fifth embodiment of the present invention.

[0156] like Figure 15 As shown, when the vessel 1 is sailing by driving the propeller 9 via the main engine 20, the first mode M31 is executed within the vessel 1. In the first mode M31, the main engine 20 drives the shaft generator 25, which generates onboard electricity. In this case, the first valve 71 is opened and the second valve 72 is closed. As a result, a portion of the vaporized gas BOG from the storage tank 10 is sent to the main supply line 100 via the first gas compressor 53 and the second gas compressor 54. The remaining portion of the vaporized gas BOG from the storage tank 10 is supplied to the main engine 20 as fuel gas FG via the first gas compressor 53, heat exchanger 56, pressurization pump 12, and high-pressure vaporizer 13. Thus, in the first mode M31, the vaporized gas BOG generated during the voyage of the vessel 1 is supplied to the main engine 20, and the shaft generator 25 generates onboard electricity.

[0157] like Figure 16As shown, when the vessel 1 is moored and the propeller 9 is not driven by the main engine 20, the second mode M32 is executed on the vessel 1. In the second mode M32, the vaporized gas BOG from the storage tank 10 is pressurized only by the first gas compressor 53 and supplied to the auxiliary engine 30 as auxiliary engine fuel gas FG2 through the auxiliary engine vaporized gas supply line 400. In the second mode M32, the vaporized gas BOG generated when the vessel 1 is moored is supplied to the auxiliary engine 30, and the auxiliary engine 30 generates onboard electricity.

[0158] (Effects)

[0159] The ship 1 of the fifth embodiment described above can supply the evaporated gas BOG, which is pressurized in two stages by the first gas compressor 53 and the second gas compressor 54, together with the liquefied gas LG flowing in the main supply line 100, as fuel to the main engine 20.

[0160] Furthermore, in the fifth embodiment described above, the evaporated gas BOG flowing in the evaporated gas line 300E is cooled by exchanging heat with the liquefied gas LG passing through the pressurization pump 12 in the heat exchanger 56. By mixing the evaporated gas BOG cooled in the heat exchanger 56 with the liquefied gas LG flowing in the main supply line 100, the evaporated gas BOG is easily reliquefied, thereby increasing the amount of evaporated gas BOG that can be reliquefied and effectively consuming the evaporated gas BOG.

[0161] Furthermore, in the fifth embodiment described above, similar to the first embodiment, a main supply line 100 is provided to supply liquefied petroleum gas (LPG) from the storage tank 10 to the main unit 20, and an evaporation gas line 300E is provided to supply evaporation gas (BOG) from the storage tank 10 to the main unit 20. This allows for efficient utilization of the evaporation gas (BOG) and improved fuel consumption efficiency.

[0162] <Postscript>

[0163] The ship 1 and the internal power generation method described in each embodiment are as follows.

[0164] (1) The vessel 1 involved in the first method comprises: a hull 2 ​​having a propeller 9; a main engine 20 disposed on the hull 2 ​​and driving the propeller 9; a shaft generator 25 driven by the rotation of the main engine 20, thereby generating internal power; a storage tank 10 disposed on the hull 2 ​​and capable of storing liquefied petroleum gas LG; a main supply pipeline 100 capable of vaporizing the liquefied petroleum gas LG in the storage tank 10 and supplying it to the main engine 20; and evaporation gas pipelines 300A to 300E capable of supplying the evaporation gas BOG in the storage tank 10 to the main engine 20.

[0165] Therefore, the main engine 20 can use both the liquefied petroleum gas (LPG) LG from the storage tank 10 and the evaporative gas (BOG) generated within the storage tank 10 as fuel. When the propeller 9 is driven in such a main engine 20, the shaft generator 25 is driven along with the rotation of the main engine 20, thereby enabling the generation of shipboard electricity using the fuel-efficient main engine 20. Therefore, even with a main engine 20 that requires high-pressure gas as fuel, the evaporative gas (BOG) can be effectively utilized to improve fuel efficiency.

[0166] (2) The vessel 1 involved in the second method is the vessel 1 of (1), which also includes: an auxiliary engine 30 that generates onboard electricity through fuel supply, and the evaporative gas pipeline 300B that can supply the evaporative gas BOG to the main engine 20 and also to the auxiliary engine 30. The vessel 1 includes: a switching unit 70 that can selectively switch the supply destination of the evaporative gas BOG based on the evaporative gas pipeline 300B between the main engine 20 and the auxiliary engine 30.

[0167] Therefore, when the main unit 20 is operating, it can supply evaporative gas BOG to the main unit 20, and when the auxiliary unit 30 is operating, it can supply evaporative gas BOG to the auxiliary unit 30. Thus, the waste of evaporative gas BOG generated in the storage tank 10 can be suppressed, and the evaporative gas BOG can be effectively consumed in the main unit 20 and the auxiliary unit 30.

[0168] (3) The vessel 1 involved in the third method is the vessel 1 of (1) or (2), wherein the main supply pipeline 100 includes: a pressurizing pump 12 for pressurizing the liquefied gas LG; and a vaporizer 13 for vaporizing the liquefied gas LG pressurized by the pressurizing pump 12 to generate fuel gas that becomes fuel for the main engine 20, and the evaporation gas pipelines 300A and 300B include: gas compressors 51 and 52 for pressurizing the evaporation gas BOG to the pressure of the fuel gas supplied to the main engine 20.

[0169] Therefore, the evaporative gas boil-off (BOG) can be used as high-pressure fuel gas supplied to the main unit 20. Thus, the BOG can be utilized effectively and fuel consumption efficiency can be improved.

[0170] (4) The vessel 1 involved in the fourth method is the vessel 1 of (2), wherein the evaporative gas pipelines 300B and 300E are equipped with: a first gas compressor 53, which pressurizes the evaporative gas BOG to a first pressure required to serve as fuel for the auxiliary engine 30; and a second gas compressor 54, which further pressurizes the BOG, which has been pressurized to the first pressure by the first gas compressor 53, to a second pressure required to serve as fuel for the main engine 20.

[0171] Therefore, the evaporative gas BOG can be pressurized in two stages by the first gas compressor 53 and the second gas compressor 54. Thus, it can be supplied to the auxiliary machine 30 as fuel, and the pressurized evaporative gas BOG can be supplied to the main machine 20 as fuel.

[0172] (5) The vessel 1 involved in the fifth method is the vessel 1 of (4), wherein the evaporation gas pipeline 300E mixes the evaporation gas BOG pressurized by the first gas compressor 53 with the liquefied gas LG flowing in the main supply pipeline 100.

[0173] Thus, by mixing the vaporized gas BOG, which is pressurized by the first gas compressor 53, with the liquefied gas LG flowing in the main supply line 100, the vaporized gas BOG and the liquefied gas LG flowing in the main supply line 100 can be supplied to the main unit 20 as fuel for the main unit 20.

[0174] (6) The vessel 1 involved in the sixth method is the vessel 1 of (5), wherein the main supply pipeline 100 includes: a pressurizing pump 12 for pressurizing the liquefied gas LG; and a vaporizer 13 for vaporizing the liquefied gas LG pressurized by the pressurizing pump 12 to generate fuel gas that becomes fuel for the main engine 20. The vessel 1 also includes: a heat exchanger 56 for exchanging heat between the evaporated gas BOG pressurized by the first gas compressor and the liquefied gas LG passing through the pressurizing pump 12 of the main supply pipeline 100.

[0175] Thus, the evaporative gas BOG is cooled before being mixed with the liquefied gas LG. Therefore, by mixing the evaporative gas BOG cooled by the heat exchanger 56 with the liquefied gas LG flowing through the main supply line 100, the evaporative gas BOG is further made easier to reliquefy.

[0176] (7) The vessel 1 involved in the seventh method is any one of (1) to (6), wherein the main supply pipeline 100 includes: a pressurizing pump 12 for pressurizing the liquefied gas LG; and a vaporizer 13 for evaporating the liquefied gas LG pressurized by the pressurizing pump 12 to generate fuel gas that becomes fuel for the main engine 20, and the vaporizing gas pipelines 300C and 300D for mixing the vaporizing gas BOG supplied to the main engine 20 with the liquefied gas LG flowing in the main supply pipeline 100.

[0177] Thus, the liquefied gas LG, which flows from the evaporated gas BOG through the main supply line 100, is cooled and reliquefied, and can therefore be effectively supplied to the main unit 20 as fuel.

[0178] (8) The vessel 1 involved in the eighth method is the vessel 1 of (7), which also includes: a heat exchanger 56, which exchanges heat between the evaporating gas BOG flowing in the evaporating gas pipeline 300D and the liquefied gas LG passing through the pressurization pump 12 of the main supply pipeline 100.

[0179] Thus, the evaporative gas BOG cooled by the heat exchanger 56 can be mixed with the liquefied gas LG flowing in the main supply line 100, making it easier to reliquefy the evaporative gas BOG.

[0180] (9) The shipboard power generation method involved in the 9th method is the shipboard power generation method in (2) of the ship 1, which switches between the following two modes: the first mode M1, M11, M21, M31, in which the evaporated gas BOG is supplied to the main engine 20 when the ship 1 is sailing, and the shipboard power is generated by the shaft generator 25; and the second mode M2, M12, M22, M32, in which the evaporated gas BOG is supplied to the auxiliary engine 30 when the ship 1 is docked, and the auxiliary engine 30 generates shipboard power.

[0181] Therefore, when the main engine 20 is running while the ship 1 is sailing, onboard electricity can be generated in the main engine 20, and when the auxiliary engine 30 is running while the ship 1 is docked, onboard electricity can be generated in the auxiliary engine 30. Thus, the evaporative air gas (BOG) wasted in the storage tank 10 can be suppressed, and the BOG can be effectively utilized to generate onboard electricity through the main engine 20 and auxiliary engine 30. As a result, fuel consumption efficiency can be improved by effectively utilizing BOG.

[0182] Industrial availability

[0183] The ship and onboard power generation method according to the present invention can effectively utilize evaporated gas, thereby improving fuel consumption efficiency.

[0184] Symbol Explanation

[0185] 1-Ship, 2-Hull, 2b-Stern, 3A, 3B-Side, 4-Bottom, 5-Upper Deck, 7-Superstructure, 8-Drive Shaft, 9-Propeller, 10-Storage Tank, 11-Pump, 12-Pressure Pump, 13-Vaporizer, 13-High-Pressure Vaporizer, 20-Main Engine, 25-Shaft Generator, 30-Auxiliary Engine, 31-Vaporizer for Auxiliary Engine, 51-High-Pressure Gas Compressor (Gas Compressor), 51, 52, 55-Gas Compressor, 53-First Gas Compressor, 54-Second Gas Compressor, 56-Heat Exchanger, 70, 70B - Switching section, 71, 73 - First valve, 72, 74 - Second valve, 100 - Main supply pipeline, 105, 205, 305 - Valves, 200 - Auxiliary machine supply pipeline, 201, 301 - Upstream end, 202, 302, 303, 304, 312, 322 - Downstream end, 300A~300E - Evaporated gas pipeline, 310 - First pipeline, 320 - Second pipeline, 400 - Auxiliary machine evaporated gas supply pipeline, M1, M11, M21, M31 - First mode, M2, M12, M22, M32 - Second mode.

Claims

1. A ship having: The hull is equipped with a propeller; The main engine is mounted on the hull and drives the propeller; A shaft generator is driven by the rotation of the main engine, thereby generating power within the ship; Storage tanks, installed on the hull, are capable of storing liquefied gas; The main supply pipeline enables the liquefied gas stored in the storage tank to be vaporized and supplied to the main unit; and The evaporation gas pipeline is capable of supplying the evaporation gas generated in the storage tank to the main unit.

2. The vessel according to claim 1, further comprising: Auxiliary machinery generates onboard electricity via fuel supply. The evaporation gas pipeline can supply evaporation gas not only to the main unit but also to the auxiliary unit. The vessel is equipped with a switching unit capable of selectively switching the destination of the evaporating gas supply based on the evaporating gas pipeline between the main engine and the auxiliary engine.

3. The vessel according to claim 1 or 2, wherein, The main supply pipeline includes: a booster pump for pressurizing the liquefied gas; and a vaporizer for vaporizing the liquefied gas pressurized by the booster pump to generate fuel gas that becomes the main engine fuel. The evaporation gas pipeline includes a gas compressor capable of pressurizing the evaporation gas to the pressure of the fuel gas supplied to the main unit.

4. The vessel according to claim 2, comprising: A first gas compressor pressurizes the evaporated gas to a first pressure required to serve as fuel for the auxiliary machine; and A second gas compressor further pressurizes the evaporated gas, which has been pressurized to the first pressure by the first gas compressor, to the second pressure required to serve as fuel for the main engine.

5. The vessel according to claim 4, wherein, The evaporation gas pipeline mixes the evaporation gas, which is pressurized by the first gas compressor, with the liquefied gas flowing in the main supply pipeline.

6. The vessel according to claim 5, wherein, The main supply pipeline includes: a booster pump for pressurizing the liquefied gas; and a vaporizer for vaporizing the liquefied gas pressurized by the booster pump to generate fuel gas that becomes fuel for the main unit. The vessel also includes a heat exchanger for exchanging heat between the evaporating gas, which is pressurized by the first gas compressor, and the liquefied gas, which is supplied by the pressurization pump via the main supply line.

7. The vessel according to claim 1 or 2, wherein, The main supply pipeline includes: a booster pump for pressurizing the liquefied gas; and a vaporizer for vaporizing the liquefied gas pressurized by the booster pump to generate fuel gas that becomes fuel for the main unit. The evaporation gas pipeline mixes the evaporation gas supplied to the main unit with the liquefied gas flowing in the main supply pipeline.

8. The vessel according to claim 7, further comprising: A heat exchanger is used to exchange heat between the evaporating gas flowing in the evaporating gas pipeline and the liquefied gas supplied by the pressurized pump through the main supply pipeline.

9. A method for generating electricity on board a ship, which is the method for generating electricity on board a ship as described in claim 2, wherein the method switches between the following two modes: In the first mode, while the vessel is sailing, evaporated gas is supplied to the main engine, and the shaft generator generates onboard electricity; and In the second mode, when the ship is anchored, the evaporated gas is supplied to the auxiliary engine, which then generates onboard electricity.

Images