Marine fuel supply system

Abstract

To provide a marine fuel supply device which supplies a stored liquid fuel in multiple fuel tanks to a marine engine and which does not need to install a pump in each of the fuel tanks.SOLUTION: A marine fuel supply device comprises a buffer tank 5 to which a liquid fuel L is delivered through multiple extraction pipes 4a, 4b, 4c and 4d to pull out the liquid fuel L upwards from the liquid level of the liquid fuel L stored in multiple fuel tanks 1a, 1b, 1c and 1d, a pump 10 to supply the liquid fuel L in the buffer tank 5 to a marine engine 12, and a negative-pressurized device 8 to suck out the liquid fuel L from each of the fuel tanks 1a, 1b, 1c and 1d by making a negative pressure in the space above the liquid level of the liquid fuel L in the buffer tank 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fuel supply system for a ship that supplies liquid fuel stored in a plurality of fuel tanks to an engine of a ship, and more particularly to a fuel supply system for a ship that does not require the installation of individual pumps in each fuel tank. [Background technology]

[0002] In recent years, as described in Non-Patent Document 1, liquefied gas fuels such as liquefied ammonia and liquefied petroleum gas (LPG) have been used as ship fuel. When the voyage is long, it is necessary to carry a large amount of liquefied gas fuel on board the ship. In particular, when liquefied ammonia is used as fuel, it has a lower calorific value than petroleum gas, so it is necessary to carry a large amount of it on board.

[0003] When manufacturing large-capacity fuel tanks, heat treatment is required as a measure to prevent damage due to stress and corrosion. However, heat treatment equipment for large-capacity fuel tanks requires an annealing furnace of the same size as the fuel tank, which requires a large facility and limited installation space. For this reason, multiple small-capacity fuel tanks that can be manufactured in smaller facilities are used to ensure the required capacity.

[0004] Patent Document 1 proposes a method of supplying fuel to a pump by supplying hot air to the fuel tank to increase the internal pressure of the fuel tank. However, this method is undesirable because it requires the design pressure of the fuel tank to be sufficiently high and there is a risk of fire. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-123119 [Non-patent literature]

[0006] [Non-Patent Document 1] Nippon Kaiji Kyokai Alternative Fuel Ship Guidelines (Version 2.0) (Methanol / Ethanol / LPG / Ammonia) Part C-1 Summary of the Invention [Problem to be solved by the invention]

[0007] Fuel tanks for ships are classified into pressure vessels (pressurized type) that store fuel at room temperature and high pressure, full-refrigerated type that stores fuel at low temperature and atmospheric pressure, and semi-refrigerated type that stores fuel at semi-low temperature with an internal pressure of 1 MPa or less.

[0008] Semi-refrigerated and full-refrigerated fuel tanks are generally equipped with re-liquefaction equipment to process evaporated gases for temperature control purposes. As a measure to prevent liquid fuel leakage on board, ship regulations stipulate that the fuel outlet must be located above the liquid level, where the amount of gas leakage is small, and that the fuel must be extracted from a position above the liquid level.

[0009] In addition, pressure vessels (pressurized type) that do not need to be removed from a position above the liquid level are classified as Class 1, Class 2, and Class 3 pressure vessels according to the NK Steel Ship Rules, Part D, 10.1.3. The thickness of the copper plate, design pressure, maximum operating temperature, and design pressure of the steam pressure generator are specified for each of the Class 1 and Class 2 pressure vessels. Class 3 pressure vessels are pressure vessels that do not fall under either Class 1 or Class 2 pressure vessels.

[0010] If the fuel outlet is higher than the liquid level, a deep well pump with a tank or For this purpose, a submerged pump installed inside the tank is used. If multiple fuel tanks are installed on a ship, a deepwell or submerged pump must be installed for each fuel tank. Therefore, as the number of fuel tanks increases, the number of pumps required also increases, resulting in a significant increase in installation costs.

[0011] Furthermore, when performing maintenance on the pump, if an inner pipe surrounding the pump is installed inside the fuel tank, only the fuel inside the inner pipe needs to be treated; however, even in this case, it takes a long time to remove the pump from the fuel tank.

[0012] Furthermore, when using a deepwell pump, the height of the pump is almost equal to the height of the fuel tank, so if multiple fuel tanks are stacked one on top of the other, the pump cannot be removed from the lower fuel tank, making it impossible to stack fuel tanks one on top of the other. As a result, the number of fuel tanks that can be installed vertically in a given space cannot be increased.

[0013] Therefore, an object of the present invention is to provide a fuel supply system for a ship that supplies liquid fuel stored in multiple fuel tanks to the engine of a ship, and that does not require the installation of individual pumps in each fuel tank.

[0014] Further objects of the present invention will become apparent from the following description. [Means for solving the problem]

[0015] The above problems are solved by the following inventions. 1. A fuel supply device for a ship that supplies liquid fuel stored in a plurality of fuel tanks to an engine of the ship, a plurality of extraction pipes for extracting the liquid fuel from each of the fuel tanks, the extraction pipes being located above the liquid level of the liquid fuel stored in each of the fuel tanks; a buffer tank to which the liquid fuel is delivered via the plurality of extraction pipes; a pump that supplies the liquid fuel in the buffer tank to an engine of the ship; a negative pressure generating device that generates a negative pressure in a space above the liquid fuel level in the buffer tank and sucks out the liquid fuel from each of the fuel tanks; A fuel supply device for a ship, comprising: 2. The buffer tank is a tank that does not require the liquid to be drawn from above the tank surface. 2. The fuel supply device for a ship according to claim 1, 3. a liquid level of the liquid fuel in the buffer tank is lower than a liquid level of the liquid fuel stored in each of the fuel tanks; A siphon is formed between the liquid fuel stored in each fuel tank, through each extraction pipe, and the end of the extraction pipe in the buffer tank. 2. The fuel supply device for a ship according to claim 1, 4. The negative pressure generating device is a re-liquefaction device. 2. The fuel supply device for a ship according to claim 1, 5. The negative pressure device is a gas compressor. 2. The fuel supply device for a ship according to claim 1, 6. The negative pressure device is a denitration facility. 2. The fuel supply device for a ship according to claim 1, 7. At least two of the fuel tanks are stacked one above the other 2. The fuel supply device for a ship according to claim 1, 8. The plurality of fuel tanks are loaded onto the ship with the liquid fuel stored therein and the discharge pipes are connected thereto, and when the liquid fuel is consumed and the stored amount is reduced, the fuel tanks are detached from the discharge pipes and lowered from the ship. 8. The fuel supply device for a boat according to any one of 1 to 7 above, characterized in that: 9. A gas supply and discharge pipe is provided to connect each fuel tank to an outside facility. 8. The fuel supply device for a boat according to any one of 1 to 7 above, characterized in that: 10. a buffer tank pressure reduction pipe that connects a location downstream of a flow rate adjustment valve provided in the extraction pipe leading to the buffer tank with a location upstream of the flow rate adjustment valve and that has a pressure reduction valve provided midway; 8. The fuel supply device for a boat according to any one of 1 to 7 above, characterized in that: [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a fuel supply device for a ship that supplies liquid fuel stored in a plurality of fuel tanks to the engine of the ship, and that does not require the installation of individual pumps in each fuel tank. In this fuel supply system for a ship, it is not necessary to provide a plurality of individual pumps for each fuel tank, and liquid fuel can be supplied from the buffer tank to the ship's engine with a single pump. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a block diagram showing the configuration of a fuel supply system for a boat according to a first embodiment of the present invention; [Figure 2] FIG. 10 is a block diagram showing the configuration of a fuel supply device for a boat according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a block diagram showing the configuration of a fuel supply device for a boat according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a block diagram showing the configuration of a fuel supply device for a boat according to a fourth embodiment of the present invention. [Figure 5] FIG. 10 is a block diagram showing the configuration of a fuel supply device for a boat according to a fifth embodiment of the present invention. [Figure 6] FIG. 10 is a block diagram showing the configuration of a fuel supply device for a boat according to a sixth embodiment of the present invention. [Figure 7] FIG. 1 is a block diagram showing the configuration of a fuel supply device for a marine vessel according to a first improved embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments of the present invention will now be described.

[0019] [First embodiment] A fuel supply system for a boat according to the present invention is a fuel supply system for a boat that supplies liquid fuel stored in a plurality of fuel tanks to an engine of a boat. FIG. 1 is a block diagram showing the configuration of a fuel supply system for a boat according to a first embodiment of the present invention.

[0020] 1, the marine fuel supply system of this embodiment includes a plurality of fuel tanks 1a, 1b, 1c, and 1d that store liquid fuel L to be supplied to the marine engine. In this description, the number of fuel tanks 1a, 1b, 1c, and 1d is four, but this number is not limited thereto and may be two, three, five, or more.

[0021] A ship's engines include all engines that generate energy by burning liquid fuel L, such as propulsion engines, generators, and boilers.

[0022] In this embodiment, the liquid fuel L is a liquefied gas fuel such as liquefied ammonia (NH3), liquefied natural gas (LNG), or liquefied petroleum gas (LPG).

[0023] Each of the fuel tanks 1a, 1b, 1c, and 1d is provided with a plurality of extraction pipes 4a, 4b, 4c, and 4d for extracting the liquid fuel L above the liquid level of the stored liquid fuel L. The extraction pipes 4a, 4b, 4c, and 4d are joined together midway through the portions corresponding to the fuel tanks 1a, 1b, 1c, and 1d to form a single pipe that leads to a buffer tank 5.

[0024] The extraction pipes 4a, 4b, 4c, and 4d are provided with on-off valves 6a, 6b, 6c, and 6d corresponding to the fuel tanks 1a, 1b, 1c, and 1d, respectively. In addition, a flow rate control valve 7 is provided at the joint of the extraction pipes 4a, 4b, 4c, and 4d.

[0025] A gas treatment device 14 is connected to the joint of the withdrawal pipes 4a, 4b, 4c, and 4d. The gas treatment device 14 treats the gas in the withdrawal pipes 4a, 4b, 4c, and 4d. Examples of gas treatment include purging.

[0026] The withdrawal pipes 4a, 4b, 4c, and 4d may not be joined together, but may be individually connected to the buffer tank 5. In this case, a plurality of flow control valves 7 and gas processing devices 14 are provided for each of the withdrawal pipes 4a, 4b, 4c, and 4d.

[0027] 1 to 7, the piping from each of the extraction pipes 4a, 4b, 4c, and 4d to the gas treatment device 14 is indicated by dotted lines indicating the gas flow path, but there is a possibility that liquid (liquid droplets) may be mixed in these piping. In this case, it is preferable to provide a gas-liquid separator and send only the gas to the gas treatment device 14 through the gas-liquid separator.

[0028] Liquid fuel L is delivered to the buffer tank 5 through a plurality of extraction pipes 4a, 4b, 4c, and 4d. A re-liquefaction device 8, which is a negative pressure generating device that creates a negative pressure in the space above the liquid surface of the liquid fuel L in the buffer tank 5 and sucks out the liquid fuel L from each of the fuel tanks 1a, 1b, 1c, and 1d, is connected to the buffer tank 5. A pressure reducing valve 9 is provided between the buffer tank 5 and the re-liquefaction device 8. The pressure reducing valve 9 is an on-off valve.

[0029] In this embodiment, the negative pressure device is a re-liquefaction device 8. The re-liquefaction device 8 compresses, or compresses and cools, the vaporized gas in the space above the liquid level of the liquid fuel L in the buffer tank 5 to re-liquefy it. In FIG. 1, the liquid flow path is indicated by a solid line, and the gas flow path is indicated by a dotted line. This is also true in other drawings described later. Note that in some of the other embodiments described later, the negative pressure device is a gas compressor and / or denitration equipment.

[0030] The liquid fuel L in the buffer tank 5 is supplied by a pump 10 through a mixing tank 11 and via a fuel supply line to an engine 12 of the ship, for example, a propulsion engine. In the mixing tank 11, the liquid fuel L from the buffer tank 5 is mixed with the liquid fuel reliquefied by the reliquefaction device 8. The liquid fuel reliquefied by the reliquefaction device 8 is sent to the mixing tank 11 through a check valve 8a, mixed with the liquid fuel L from the buffer tank 5, and supplied to the engine 12 of the ship. The mixing tank 11 may be replaced with a mixer.

[0031] The fuel supply line may be provided with various devices (not shown) for supplying fuel to the ship's engine 12, as well as a gas-liquid separator. Examples of the various devices for supplying fuel include a compressor, a high-pressure pump, and a heat exchanger. In addition, the fuel supply line may be supplied with inert gas to purge residual vaporized gas when the ship's engine 12 is started, stopped, or in an emergency shutdown, and this inert gas, together with the residual vaporized gas, is introduced into the detoxification device via a gas-liquid separator. The gas-liquid separator through which the gas introduced into the detoxification device passes may also be used for the gas sent to the gas treatment device 14. In this case, if the buffer tank 5 is empty, the gas in the extraction pipes 4a, 4b, 4c, and 4d passes through the buffer tank 5, the fuel supply line, and the gas-liquid separator, and is sent to the gas treatment device 14 for treatment.

[0032] In this embodiment, the liquid fuel reliquefied by the reliquefaction device (negative pressure device) 8 is used in the ship's engine 12, so that the liquid fuel is used without waste. Note that the liquid fuel reliquefied by the reliquefaction device 8 may be used in the ship's auxiliary engine instead of the main engine.

[0033] In this fuel supply device for a ship, the liquid fuel L in the buffer tank 5 can be supplied to the ship's engine 12 by one pump 10, eliminating the need to provide multiple pumps for each of the fuel tanks 1a, 1b, 1c, and 1d. This simplifies pump maintenance and reduces installation costs.

[0034] The buffer tank 5 may be provided with upper and lower liquid level sensors (level switches) 13u, 13d for controlling the liquid level position in the buffer tank 5. The upper liquid level sensor 13u is provided at the upper limit position of the liquid level of the liquid fuel L in the buffer tank 5. The lower liquid level sensor 13d is provided at the lower limit position of the liquid level of the liquid fuel L in the buffer tank 5.

[0035] When the upper liquid level sensor 13u detects the liquid level of the liquid fuel L, the flow rate control valve 7 is controlled to be closed, and the liquid fuel L is stopped from being sent from each of the fuel tanks 1a, 1b, 1c, and 1d to the buffer tank 5. When the lower liquid level sensor 13d detects the liquid level of the liquid fuel L, the flow rate control valve 7 and the pressure reducing valve 9 are controlled to be open, which enables the pressure inside the buffer tank 5 to be reduced and the liquid fuel L to be sent to the buffer tank 5. The amount of liquid fuel L sent to the buffer tank 5 is adjusted by the opening of the flow rate control valve 7.

[0036] A supply pipe 2 for supplying liquid fuel L from a bunkering facility 100 outside the ship, such as a bunker ship, is connected to each of the fuel tanks 1a, 1b, 1c, and 1d. The supply pipe 2 has one pipe connected to the bunkering facility 100, which branches off at the fuel tanks 1a, 1b, 1c, and 1d sides and is connected to each of the fuel tanks 1a, 1b, 1c, and 1d. Opening and closing valves 3a, 3b, 3c, and 3d are provided in the branched portions of the supply pipe 2 corresponding to each of the fuel tanks 1a, 1b, 1c, and 1d.

[0037] To supply liquid fuel L to each fuel tank 1a, 1b, 1c, and 1d through supply pipe 2, one pipe on the bunkering equipment 100 side is connected to the bunkering equipment 100, each on-off valve 3a, 3b, 3c, and 3d is opened, and the liquid fuel L is sent to each fuel tank 1a, 1b, 1c, and 1d by the pump of the bunkering equipment 100.

[0038] [About the buffer tank] The buffer tank 5 is preferably a tank that does not require withdrawal from above the liquid level, such as a pressure vessel as defined in the NK Steel Ship Rules. If the buffer tank 5 does not require withdrawal from above the liquid level, the liquid fuel L in the buffer tank 5 may be withdrawn from below the liquid level. Therefore, various pumps, such as diaphragm pumps and canned motor pumps, can be used as the pump 10 that supplies liquid fuel L from the buffer tank 5 to the ship's engine 12. Diaphragm pumps and canned motor pumps are preferred because they can easily pump liquid at high pressure. Submerged pumps and deepwell pumps cannot reach the desired pressure in a single stage for some fluids, so they are designed to use a two-stage pressure boost. Diaphragm pumps and canned motor pumps can reach the desired pressure in a single stage.

[0039] According to the NK Steel Ship Rules, Part D, 13.9.1-7, each fuel tank 1a, 1b, 1c, and 1d must have a capacity that can maintain the ship's engine (main engine) 12 at maximum continuous output and the generator at normal load for at least eight hours. On the other hand, if fuel tanks 1a, 1b, 1c, and 1d are present, buffer tank 5 is considered a process pressure vessel as defined by the NK Steel Ship Rules. Process pressure vessels as defined by the NK Steel Ship Rules are not subject to the requirement to drain liquid from above the tank's liquid level.

[0040] Here, the NK Rules for Steel Ships refer to the rules for steel ships issued by Nippon Kaiji Kyokai (ClassNK).

[0041] [Regarding the formation of siphons from each fuel tank] It is preferable that the liquid level of the liquid fuel L in the buffer tank 5 be lower than the liquid level of the liquid fuel L stored in each of the fuel tanks 1a, 1b, 1c, and 1d so that a siphon is formed from the liquid fuel L stored in each of the fuel tanks 1a, 1b, 1c, and 1d through each of the withdrawal pipes 4a, 4b, 4c, and 4d to the end of the withdrawal pipe in the buffer tank 5. When the siphon is formed, the liquid fuel L is sucked out of each of the fuel tanks 1a, 1b, 1c, and 1d and sent to the buffer tank 5 without the need to reduce the pressure inside the buffer tank 5 by the re-liquefaction device 8. This reduces the energy consumption of the re-liquefaction device 8.

[0042] [About stacking fuel tanks] At least two of the fuel tanks 1a, 1b, 1c, and 1d are stacked one above the other. By stacking the fuel tanks 1a, 1b, 1c, and 1d one on top of the other, the floor area occupied by the fuel tank per stored amount of fuel is reduced, and combined with the fact that the pump is installed separately, volume can be saved.

[0043] [Reducing bunkering time] In this marine fuel supply system, it is also preferable that the multiple fuel tanks 1a, 1b, 1c, and 1d are loaded onto the marine vessel while storing liquid fuel L, and are connected to extraction pipes 4a, 4b, 4c, and 4d, and then, when the liquid fuel L is consumed and the stored amount decreases, the fuel tanks are detached from the extraction pipes 4a, 4b, 4c, and 4d and unloaded from the marine vessel. In this case, the supply pipe 2 is not necessary. In this case, it is also preferable to use IBC tanks (Intermediate Bulk Container Tanks) as the fuel tanks 1a, 1b, 1c, and 1d. Because IBC tanks are container-shaped, this reduces the amount of reloading work.

[0044] When the fuel tanks 1a, 1b, 1c, 1d are separated from the withdrawal pipes 4a, 4b, 4c, 4d, the on-off valves 6a, 6b, 6c, 6d and the flow rate control valve 7 are closed, and the insides of the withdrawal pipes 4a, 4b, 4c, 4d between the on-off valves 6a, 6b, 6c, 6d and the flow rate control valve 7 are purged by the gas treatment device 14, and the purged sections are separated to prevent leakage of liquid fuel from the withdrawal pipes 4a, 4b, 4c, 4d. For safety reasons, one more on-off valve 6a, 6b, 6c, 6d may be added.

[0045] If multiple fuel tanks 1a, 1b, 1c, and 1d are loaded onto a ship with liquid fuel L stored therein and then unloaded from the ship with a reduced amount of liquid fuel L stored therein, each fuel tank 1a, 1b, 1c, and 1d can be filled with liquid fuel L in advance, thereby significantly shortening the bunkering time without relying on the supply flow rate of equipment such as pumps that bunker the liquid fuel.

[0046] Second Embodiment Fig. 2 is a block diagram showing the configuration of a fuel supply device for a boat according to a second embodiment of the present invention. The same reference numerals as in Fig. 1 designate the same components, and unless otherwise specified, the description in Fig. 1 is used and will not be repeated here.

[0047] In this embodiment, the liquid fuel is a liquefied gas fuel.

[0048] 2, in this embodiment, re-liquefaction device 8, which is a negative pressure device, returns the re-liquefied liquid fuel to each of the fuel tanks 1a, 1b, 1c, and 1d, rather than to mixing tank 11. The liquid fuel re-liquefied by re-liquefaction device (negative pressure device) 8 is returned to each of the fuel tanks 1a, 1b, 1c, and 1d via return pipe 16.

[0049] Return pipe 16 has one pipe connected to reliquefaction device 8, which branches off at the fuel tanks 1a, 1b, 1c, and 1d sides and is connected to each of fuel tanks 1a, 1b, 1c, and 1d. Open / close valves 15a, 15b, 15c, and 15d are provided in the branched portions of return pipe 16 corresponding to each of fuel tanks 1a, 1b, 1c, and 1d.

[0050] The liquid fuel reliquefied by the reliquefaction device 8 is returned to the fuel tanks 1a, 1b, 1c, and 1d and is used in the engine 12 of the ship, so that the liquid fuel is used without waste.

[0051] Although it depends on the amount of liquid fuel extracted from each of the fuel tanks 1a, 1b, 1c, and 1d and the amount consumed by the engine 12, in order to utilize the liquid fuel reliquefied by the reliquefaction device 8, it is preferable to return the fuel to each of the fuel tanks 1a, 1b, 1c, and 1d as described above, rather than to the buffer tank 5. This is because if the fuel is returned to the buffer tank 5, no pressure difference will occur between the inside of the fuel tanks 1a, 1b, 1c, and 1d and the inside of the buffer tank 5.

[0052] In this embodiment as well, the liquid fuel reliquefied by the negative pressure device is used in the engine 12 of the ship, so that the liquid fuel is used without waste.

[0053] Also, in this embodiment, there is no need to provide multiple pumps for each of the fuel tanks 1a, 1b, 1c, and 1d, which simplifies pump maintenance and reduces installation costs. Furthermore, stacking the fuel tanks 1a, 1b, 1c, and 1d one above the other, coupled with the fact that the pumps are installed separately, allows for volume reduction. Furthermore, when a siphon is formed from the liquid fuel L stored in each of the fuel tanks 1a, 1b, 1c, and 1d to the end of the extraction pipe in the buffer tank 5, there is no need to reduce the pressure inside the buffer tank 5, which reduces the energy consumption of the re-liquefaction device 8. If each of the fuel tanks 1a, 1b, 1c, and 1d is loaded onto the ship with liquid fuel L stored in advance, the bunkering time can be significantly reduced without relying on the supply flow rate of a bunkering pump or the like. If the buffer tank 5 is a tank that does not require the liquid to be drawn from above the tank's liquid surface, various types of pumps can be used for the buffer tank 5, such as a diaphragm pump or a canned motor pump.

[0054] Third Embodiment Figure 3 is a block diagram showing the configuration of a fuel supply device for a boat according to a third embodiment of the present invention. The same reference numerals as in Figures 1 and 2 represent the same components, and unless otherwise specified, the explanations in Figures 1 and 2 will be used and will not be repeated here.

[0055] In this embodiment, the liquid fuel L includes various liquid fuels such as methanol, heavy oil, and light oil, in addition to liquefied gas fuel.

[0056] In this embodiment, as shown in FIG. 3, a gas compressor 17 is provided as a negative pressure device instead of the reliquefaction device 8 in the second embodiment.

[0057] Gas compressor 17 compresses the gas in the space above the liquid level of liquid fuel L in buffer tank 5, creating a negative pressure in this space. The vaporized gas compressed by gas compressor 17 is returned to each of fuel tanks 1a, 1b, 1c, and 1d through return pipes 16.

[0058] As in the second embodiment, return pipe 16 has one pipe connected to gas compressor 17, which branches off at the fuel tanks 1a, 1b, 1c, and 1d sides and is connected to each of fuel tanks 1a, 1b, 1c, and 1d. On-off valves 15a, 15b, 15c, and 15d are provided in the branched portions of return pipe 16 corresponding to each of fuel tanks 1a, 1b, 1c, and 1d.

[0059] The gas compressor 17 is activated when the lower liquid level sensor 13d detects the liquid level of the liquid fuel L, reduces the pressure inside the buffer tank 5, and pressurizes the inside of each fuel tank 1a, 1b, 1c, and 1d, thereby sending the liquid fuel L to the buffer tank 5.

[0060] In this embodiment, the gas in the buffer tank 5 is returned to each of the fuel tanks 1a, 1b, 1c, and 1d, thereby increasing the pressure difference between the air pressure in the buffer tank 5 and the air pressure in each of the fuel tanks 1a, 1b, 1c, and 1d, and therefore the liquid fuel L in each of the fuel tanks 1a, 1b, 1c, and 1d, which is at a high pressure, is efficiently transferred into the buffer tank 5, which is at a low pressure.

[0061] Furthermore, if the liquid fuel L is a liquefied gas fuel, the liquid fuel that is returned to each fuel tank 1a, 1b, 1c, and 1d and re-liquefied is used in the ship's engine 12, which has the effect of ensuring that the liquid fuel is used without waste.

[0062] Also, in this embodiment, there is no need to provide multiple pumps for each of the fuel tanks 1a, 1b, 1c, and 1d, which simplifies pump maintenance and reduces installation costs. Furthermore, stacking the fuel tanks 1a, 1b, 1c, and 1d one above the other, coupled with the fact that the pumps are installed separately, allows for volume reduction. Furthermore, when a siphon is formed from the liquid fuel L stored in each of the fuel tanks 1a, 1b, 1c, and 1d to the end of the extraction pipe in the buffer tank 5, there is no need to reduce the pressure inside the buffer tank 5, which reduces the energy consumption of the negative pressure device. If each of the fuel tanks 1a, 1b, 1c, and 1d is loaded onto the ship with liquid fuel L stored in advance, the bunkering time can be significantly reduced without relying on the supply flow rate of a bunkering pump or the like. If the buffer tank 5 is a tank that does not require the liquid to be drawn from above the tank's liquid surface, various types of pumps can be used for the buffer tank 5, such as a diaphragm pump or a canned motor pump.

[0063] [Fourth embodiment] Fig. 4 is a block diagram showing the configuration of a fuel supply device for a boat according to a fourth embodiment of the present invention. The same reference numerals as in Fig. 1 designate the same components, and unless otherwise specified, the description in Fig. 1 will be used and will not be repeated here.

[0064] In this embodiment, the liquid fuel is liquefied ammonia.

[0065] In this embodiment, as shown in FIG. 4, a gas compressor 17 is provided as a negative pressure device in place of the reliquefaction device 8 in the first embodiment.

[0066] The gas compressor 17 compresses the vaporized gas in the space above the liquid level of the liquid fuel L in the buffer tank 5, creating a negative pressure in this space. The vaporized gas compressed by the gas compressor 17 is sent to the condensed water tank 18.

[0067] When the lower liquid level sensor 13d detects the liquid level of the liquid fuel L, the gas compressor 17 is operated to reduce the pressure inside the buffer tank 5 and send the liquid fuel L to the buffer tank 5.

[0068] Condensed water (liquefied ammonia) is sent from the condensed water tank 18 to the mixing tank 11 via the check valve 8a, mixed with the liquid fuel L from the buffer tank 5, and supplied to the engine 12 of the ship.

[0069] In this embodiment, the condensed water condensed by the negative pressure device is used in the engine 12 of the ship, so that the liquid fuel is used without waste.

[0070] Also, in this embodiment, there is no need to provide multiple pumps for each of the fuel tanks 1a, 1b, 1c, and 1d, which simplifies pump maintenance and reduces installation costs. Furthermore, stacking the fuel tanks 1a, 1b, 1c, and 1d one above the other, coupled with the fact that the pumps are installed separately, allows for volume reduction. Furthermore, when a siphon is formed from the liquid fuel L stored in each of the fuel tanks 1a, 1b, 1c, and 1d to the end of the extraction pipe in the buffer tank 5, there is no need to reduce the pressure inside the buffer tank 5, which reduces the energy consumption of the negative pressure device. Each fuel tank 1a, 1b, 1c, and 1d is loaded onto the ship with liquid fuel L stored in advance. By doing so, the bunkering time can be significantly reduced without depending on the supply flow rate of the bunkering pump or the like. If the buffer tank 5 is a tank that does not require the liquid to be drawn from above the tank's liquid surface, various types of pumps can be used for the buffer tank 5, such as a diaphragm pump or a canned motor pump.

[0071] Fifth Embodiment Fig. 5 is a block diagram showing the configuration of a fuel supply device for a boat according to a fifth embodiment of the present invention. The same reference numerals as in Fig. 1 represent the same components, and unless otherwise specified, the description in Fig. 1 will be used and will not be repeated here.

[0072] In this embodiment, the liquid fuel is liquefied ammonia.

[0073] In this embodiment, as shown in Fig. 5, a denitration system 19 is provided as a negative pressure device instead of the reliquefaction system 8 in the first embodiment. The denitration system 19 is a denitration system for exhaust gas such as a catalytic reduction device.

[0074] Vaporized gas in the space above the liquid level of the liquid fuel L in the buffer tank 5 is sent to the denitration equipment 19 via the pressure reducing valve 9, and the denitration equipment 19 denitrifies this vaporized gas. The denitration equipment 19 creates a negative pressure in the space above the liquid level of the liquid fuel L in the buffer tank 5, causing the liquid fuel L to be sent to the buffer tank 5. When the lower liquid level sensor 13d detects the liquid level of the liquid fuel L, the pressure reducing valve 9 is controlled to open, allowing the vaporized gas in the buffer tank 5 to be denitrified.

[0075] The vaporized gas in the space above the liquid surface of the liquid fuel L in the buffer tank 5 may be supplied to a reducing agent manufacturing device and stored as a reducing agent.

[0076] In this embodiment, the vaporized gas in the buffer tank 5 is used for denitration by the denitration equipment 19, so that the liquid fuel is used without waste.

[0077] Also, in this embodiment, there is no need to provide multiple pumps for each of the fuel tanks 1a, 1b, 1c, and 1d, which simplifies pump maintenance and reduces installation costs. Furthermore, stacking the fuel tanks 1a, 1b, 1c, and 1d one above the other, coupled with the fact that the pumps are installed separately, allows for volume reduction. Furthermore, when a siphon is formed from the liquid fuel L stored in each of the fuel tanks 1a, 1b, 1c, and 1d to the end of the extraction pipe in the buffer tank 5, there is no need to reduce the pressure inside the buffer tank 5, which reduces the energy consumption of the negative pressure device. If each of the fuel tanks 1a, 1b, 1c, and 1d is loaded onto the ship with liquid fuel L stored in advance, the bunkering time can be significantly reduced without relying on the supply flow rate of a bunkering pump or the like. If the buffer tank 5 is a tank that does not require the liquid to be drawn from above the tank's liquid surface, various types of pumps can be used for the buffer tank 5, such as a diaphragm pump or a canned motor pump.

[0078] Sixth Embodiment Figure 6 is a block diagram showing the configuration of a fuel supply device for a boat according to a sixth embodiment of the present invention. The same reference numerals as in Figures 1 and 5 designate the same components, and unless otherwise specified, the explanations in Figures 1 and 5 will be used and will not be repeated here.

[0079] In this embodiment, the liquid fuel is liquefied ammonia.

[0080] In this embodiment, as shown in FIG. 6, a gas compressor 17 and a denitration facility 19 are provided as a negative pressure device in place of the reliquefaction device 8 in the first embodiment.

[0081] The gas compressor 17 compresses the vaporized gas in the space above the liquid level of the liquid fuel L in the buffer tank 5, creating a negative pressure in this space. The vaporized gas compressed by the gas compressor 17 is sent to a denitration facility 19.

[0082] In this embodiment, by providing both the gas compressor 17 and the denitration equipment 19 as negative pressure generating devices, the space above the liquid surface of the liquid fuel L in the buffer tank 5 can be efficiently made negative pressure.

[0083] When the lower liquid level sensor 13d detects the liquid level of the liquid fuel L, the gas compressor 17 is activated to send the vaporized gas to the denitration equipment 19, reduce the pressure inside the buffer tank 5, and send the liquid fuel L to the buffer tank 5.

[0084] In this embodiment as well, the vaporized gas in the space above the liquid surface of the liquid fuel L in the buffer tank 5 may be supplied to the reducing agent production device and stored as a reducing agent.

[0085] In this embodiment as well, the vaporized gas in the buffer tank 5 is used for denitration by the denitration equipment 19, so that the liquid fuel is used without waste.

[0086] Also, in this embodiment, there is no need to provide multiple pumps for each of the fuel tanks 1a, 1b, 1c, and 1d, which simplifies pump maintenance and reduces installation costs. Furthermore, stacking the fuel tanks 1a, 1b, 1c, and 1d one above the other, coupled with the fact that the pumps are installed separately, allows for volume reduction. Furthermore, when a siphon is formed from the liquid fuel L stored in each of the fuel tanks 1a, 1b, 1c, and 1d to the end of the extraction pipe in the buffer tank 5, there is no need to reduce the pressure inside the buffer tank 5, which reduces the energy consumption of the negative pressure device. If each of the fuel tanks 1a, 1b, 1c, and 1d is loaded onto the ship with liquid fuel L stored in advance, the bunkering time can be significantly reduced without relying on the supply flow rate of a bunkering pump or the like. If the buffer tank 5 is a tank that does not require the liquid to be drawn from above the tank's liquid surface, various types of pumps can be used for the buffer tank 5, such as a diaphragm pump or a canned motor pump.

[0087] [First improved form] Fig. 7 is a block diagram showing the configuration of a fuel supply device for a ship according to a first improved embodiment of the present invention. The same reference numerals as in Fig. 1 represent the same components, and unless otherwise specified, the description in Fig. 1 will be used and will not be repeated here.

[0088] As shown in Fig. 7, this improved embodiment is configured by adding a gas supply / discharge pipe 20 and a buffer tank decompression pipe 22 to the marine fuel supply device of the first embodiment (Fig. 1). Note that only one of the gas supply / discharge pipe 20 and the buffer tank decompression pipe 22 may be added.

[0089] The gas supply / discharge pipe 20 and / or the buffer tank decompression pipe 22 can also be added to the fuel supply devices for a boat according to the second to sixth embodiments (FIGS. 2 to 6). The configurations and functions of the gas supply and discharge pipe 20 and the buffer tank pressure reduction pipe 22 are the same as those of the gas supply and discharge pipe 20 and the buffer tank pressure reduction pipe 22 in this improved embodiment when added to any of the marine fuel supply devices of the second to sixth embodiments (Figures 2 to 6), and therefore will not be described here.

[0090] [Gas supply and discharge pipe 20] The gas supply and discharge pipe 20 is a pipe connected to outside equipment, which branches off at the fuel tanks 1a, 1b, 1c, and 1d sides and is connected to the fuel tanks 1a, 1b, 1c, and 1d. At the branched portions of the gas supply / discharge pipe 20, on-off valves 21a, 21b, 21c, and 21d are provided corresponding to the fuel tanks 1a, 1b, 1c, and 1d, respectively.

[0091] Here, the off-board equipment includes not only the bunkering equipment 100 but also gas treatment equipment on a bunker ship (not shown) and gas treatment equipment on land. The gas supply and discharge pipe 20 is a pipe for supplying or discharging gas between outside equipment and each fuel tank 1a, 1b, 1c, and 1d, and is therefore preferably connected to a location that will be the gas phase if liquid is present in each fuel tank 1a, 1b, 1c, and 1d.

[0092] By providing the gas supply and discharge pipe 20, preparations can be made before new liquid fuel L is poured into each of the fuel tanks 1a, 1b, 1c, and 1d. Also, preparations can be made before inspecting the inside of each of the fuel tanks 1a, 1b, 1c, and 1d.

[0093] Common operations for these two preparations include gasifying (gas vaporizing) the liquid fuel L remaining in each of the fuel tanks 1a, 1b, 1c, and 1d, and detoxifying the gas. Preparations before adding new liquid fuel L include gasifying the liquid fuel L remaining in each fuel tank 1a, 1b, 1c, and 1d (Gas Vaporizing), removing moisture (Drying), supplying inert gas (Innerting), removing impurities (Gassing up), and pre-cooling (Cool down). Preparations before inspections include gasifying the liquid fuel L remaining in each of the fuel tanks 1a, 1b, 1c, and 1d (gas vaporizing), increasing the oxygen concentration (aeration), and the like.

[0094] (Operations common to both preparation operations) The preparation operation for each of the fuel tanks 1a, 1b, 1c, and 1d using the gas supply and discharge pipe 20 is carried out when the liquid fuel L in each of the fuel tanks 1a, 1b, 1c, and 1d has all been used up.

[0095] Even if all the liquid fuel L is used up, the liquid fuel L or gas volatilized from the liquid fuel L may remain in each fuel tank 1a, 1b, 1c, and 1d, so if any liquid fuel L remains, it is gasified. The remaining liquid fuel L is gasified by opening the on-off valves 21a, 21b, 21c, and 21d and heating the liquid fuel L remaining in each of the fuel tanks 1a, 1b, 1c, and 1d, or by supplying heated gas or applying pressure (gas vaporizing). At this time, the inside of each of the fuel tanks 1a, 1b, 1c, and 1d is heated. If the remaining gas resulting from gasification of the remaining liquid fuel L and / or the remaining gas cannot be released into the atmosphere, it must be supplied to a gas treatment facility on board the ship, outside the ship such as a bunker ship, or on land for detoxification treatment. Since on-shore gas treatment facilities have a greater treatment capacity than the on-board gas treatment device 14, it is preferable to use the gas supply and discharge pipe 20 to send the remaining gas to the on-shore gas treatment facility for treatment.

[0096] (Preparation before adding new liquid fuel L) Before filling each fuel tank 1a, 1b, 1c, 1d with new liquid fuel L, first, in order to prevent condensation inside each fuel tank 1a, 1b, 1c, 1d, on-off valves 21a, 21b, 21c, 21d are opened and dry air is supplied to each fuel tank 1a, 1b, 1c, 1d using gas supply and discharge pipe 20, thereby removing moisture inside each fuel tank 1a, 1b, 1c, 1d (drying).

[0097] Next, an inert gas is supplied (innerting) to each of the fuel tanks 1a, 1b, 1c, and 1d using the gas supply and discharge pipes 20. If the gas volatilizing from the newly supplied liquid fuel L is a flammable gas, there is a possibility of it exploding if the oxygen concentration is high, so the oxygen concentration in each fuel tank 1a, 1b, 1c, and 1d can be lowered to below the lower explosion limit. Furthermore, if the gas volatilizing from the newly supplied liquid fuel L is a toxic gas (e.g., NH3), a high oxygen concentration may cause stress corrosion cracking depending on the material of each fuel tank 1a, 1b, 1c, and 1d, so the oxygen concentration can be kept low. Furthermore, if gas that has evaporated from the liquid fuel L remains in each of the fuel tanks 1a, 1b, 1c, and 1d, the supply of inert gas also removes this remaining gas.

[0098] Next, the inert gas in each of the fuel tanks 1a, 1b, 1c, and 1d is replaced with gas volatilized from the liquid fuel L using the gas supply and discharge pipe 20, thereby removing impurities from each of the fuel tanks 1a, 1b, 1c, and 1d (gassing up).

[0099] Furthermore, if the liquid fuel L is a fuel that requires cooling, it is necessary to pre-cool the inside of each fuel tank 1a, 1b, 1c, and 1d, so that gas that has been evaporated and cooled from the liquid fuel L is supplied to pre-cool the inside of each fuel tank 1a, 1b, 1c, and 1d (cool down).

[0100] Then, the on-off valves 21a, 21b, 21c, and 21d are closed, and the liquid fuel L is supplied from the bunkering facility 100 through the supply pipe 2 to each of the fuel tanks 1a, 1b, 1c, and 1d (Loading).

[0101] The temperature of each fuel tank 1a, 1b, 1c, and 1d can also be adjusted by spraying liquefied gas such as liquid fuel L. However, when the flow rate of the liquid fuel L supplied through the supply pipe 2 is large (for example, 700 m 3 / h), the heat absorption of the liquid fuel L becomes excessive, so a small flow rate (10 m 3 / h), making it difficult to uniformly adjust the temperature of each fuel tank 1a, 1b, 1c, 1d. Therefore, it is easier to adjust the temperature of each fuel tank 1a, 1b, 1c, 1d by supplying cooled gas from an onshore facility.

[0102] The gas may be supplied from the bunkering facility 100 through the supply pipe 2 and the pressure may be released through the gas supply and discharge pipe 20.

[0103] (Preparation before inspection, etc.) Preparations before inspecting each of the fuel tanks 1a, 1b, 1c, and 1d are made by first opening the on-off valves 21a, 21b, 21c, and 21d and supplying dry air into each of the fuel tanks 1a, 1b, 1c, and 1d using the gas supply and discharge pipes 20. This is to increase the oxygen concentration (aeration) so that workers can enter each of the fuel tanks 1a, 1b, 1c, and 1d. If the oxygen concentration inside each of the fuel tanks 1a, 1b, 1c, and 1d is low, workers will not be able to enter inside. Furthermore, if gas that has evaporated from the liquid fuel L remains in each of the fuel tanks 1a, 1b, 1c, and 1d, the supply of dry air also removes this remaining gas.

[0104] Then, the on-off valves 21a, 21b, 21c, and 21d are closed, and the insides of the fuel tanks 1a, 1b, 1c, and 1d are inspected.

[0105] [Buffer tank decompression pipe 22] The buffer tank decompression pipe 22 is a pipe that connects a location downstream of the flow rate control valve 7 at the junction of the extraction pipes 4a, 4b, 4c, and 4d with a location upstream of the flow rate control valve 7. A pressure reducing valve 23 is provided midway along the buffer tank decompression pipe 22.

[0106] By providing the buffer tank decompression pipe 22, the buffer tank 5 can be emptied in preparation for inspection of the buffer tank 5 and the pump 10, for example. If there is any residual gas in the buffer tank 5, this residual gas passes through the buffer tank pressure reducing pipe 22, the pressure reducing valve 23, and the junction of the extraction pipes 4a, 4b, 4c, and 4d (upstream of the flow control valve 7), and is sent to the gas treatment device 14, where it is detoxified. Since the gas treatment device 14 has a flow rate restriction, the pressure reducing valve 23 adjusts the gas flow rate through the buffer tank pressure reducing pipe 22 to match the flow rate restriction of the gas treatment device 14 .

[0107] It is possible to consider making the flow control valve 7 a two-way valve and using it also as a pressure reducing valve to empty the buffer tank 5, but since the flow control valve 7 is a valve for liquids and cannot adjust the gas flow rate, there is great significance in providing a separate pressure reducing valve 23 for gases.

[0108] The pressure reducing valve 23 may be provided inside the gas treatment device 14. In this case, the vaporization rate becomes higher than the treatment rate, resulting in a high pressure, so it is preferable to increase the design pressure of each device and piping.

[0109] The remaining gas can be sent from the buffer tank 5 to the gas processing device 14 by the suction force of a suction device such as a compressor that is optionally provided in the gas processing device 14. Alternatively, the remaining gas can be sent from the buffer tank 5 to the gas processing device 14 by providing a separate dedicated line from a gas supply device (not shown) and pumping the gas into the buffer tank 5. From the viewpoint of ensuring safety, it is preferable that the gas pressure-fed into the buffer tank 5 be an inert gas.

[0110] Furthermore, the buffer tank decompression pipe 22 can also be used as an exhaust pipe when purging with an inert gas and ventilating to ensure safety when opening the buffer tank 5. This inert gas is, for example, N2 gas or oxygen-depleted air. In this case, the inert gas for purging and ventilation can be supplied to the buffer tank 5 by pressure from an inert gas supply device (not shown) through a separate dedicated line. In addition, this inert gas may be supplied from the inert gas supply device into the buffer tank 5 and discharged from the buffer tank 5 by the suction force of a suction device such as a compressor optionally provided in the gas processing device 14, rather than by pressure feeding.

[0111] Although each embodiment has been described above, the present invention is not limited to these embodiments, and various improvements and design changes may be made within the scope that does not deviate from the spirit of the present invention, and each embodiment may also be combined with each other. [Explanation of symbols]

[0112] 1a Fuel tank 1b Fuel tank 1c Fuel Tank 1d fuel tank 2 Supply pipe 3a On-off valve 3b On-off valve 3c On-off valve 3d On-off valve 4a Extraction piping 4b Withdrawal piping 4c Extraction piping 4d Extraction piping 5 Buffer Tank 6a On-off valve 6b On-off valve 6c On-off valve 6d On-off valve 7. Flow control valve 8 Reliquefaction equipment 8a Check valve 9 Pressure reducing valve 10 Pump 11 Mixing tank 12 Ship's engine 13u Upper Liquid Level Sensor 13d Lower liquid level sensor 14 Gas treatment equipment 15a On-off valve 15b On-off valve 15c On-off valve 15d On-off valve 16 Return pipe 17 Gas Compressor 18 Condensate tank 19 Denitration equipment 20 Gas supply and discharge pipe 21a On-off valve 21b On-off valve 21c On-off valve 21d On-off valve 22 Buffer tank pressure reducing pipe 23 Pressure reducing valve 100 Bunkering Equipment L liquid fuel

Claims

1. A fuel supply device for a ship that supplies liquid fuel stored in a plurality of fuel tanks to an engine of the ship, a plurality of extraction pipes for extracting the liquid fuel from each of the fuel tanks, the extraction pipes being located above the liquid level of the liquid fuel stored in each of the fuel tanks; a buffer tank to which the liquid fuel is delivered via the plurality of extraction pipes; a pump that supplies the liquid fuel in the buffer tank to an engine of the ship; a negative pressure generating device that generates a negative pressure in a space above the liquid fuel level in the buffer tank and sucks out the liquid fuel from each of the fuel tanks; Equipped with a buffer tank pressure reduction pipe that connects a location downstream of a flow rate adjustment valve provided in the extraction pipe leading to the buffer tank with a location upstream of the flow rate adjustment valve and that has a pressure reduction valve provided midway; A fuel supply device for a ship.

2. The buffer tank is a tank that does not require the liquid to be drawn from above the tank surface.

2. The fuel supply system for a boat according to claim 1.

3. a liquid level of the liquid fuel in the buffer tank is lower than a liquid level of the liquid fuel stored in each of the fuel tanks; A siphon is formed between the liquid fuel stored in each fuel tank, through each extraction pipe, and the end of the extraction pipe in the buffer tank.

2. The fuel supply system for a boat according to claim 1.

4. The negative pressure generating device is a re-liquefaction device.

2. The fuel supply system for a boat according to claim 1.

5. The negative pressure device is a gas compressor.

2. The fuel supply system for a boat according to claim 1.

6. The negative pressure device is a denitration facility.

2. The fuel supply system for a boat according to claim 1.

7. At least two of the fuel tanks are stacked one above the other.

2. The fuel supply system for a boat according to claim 1.

8. The plurality of fuel tanks are loaded onto the ship with the liquid fuel stored therein and the discharge pipes are connected thereto, and when the liquid fuel is consumed and the stored amount is reduced, the fuel tanks are detached from the discharge pipes and lowered from the ship.

8. A fuel supply system for a boat according to claim 1.

9. A gas supply and discharge pipe is provided to connect each fuel tank to an outside facility.

8. A fuel supply system for a boat according to claim 1.

Images