Ammonia water storage system and ammonia fuel ship

Abstract

To provide an ammonia water storage system and an ammonia fuel ship capable of achieving reduction in an influence on a human body and an environment caused by ammonia leakage.SOLUTION: An ammonia water storage system 1 includes: an ammonia water storage tank 2 for storing ammonia gas or ammonia water generated on a ship in a state of ammonia water; a recovery line 3 for conveying the ammonia gas or the ammonia water to the ammonia water storage tank 2; a water supply line 4 for supplying sea water to the ammonia water storage tank 2; a drainage line 5 for draining the ammonia water stored in the ammonia water storage tank 2 to the outside of the ship; a concentration meter 6 for measuring the concentration of the ammonia water stored in the ammonia water storage tank 2; and a control device 7 for performing such control that the sea water is supplied to the ammonia water storage tank 2 based on the measurement value of the concentration meter 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ammonia water storage system and an ammonia-fueled ship, and more particularly to an ammonia water storage system capable of temporarily storing ammonia water on board a ship and an ammonia-fueled ship equipped with the ammonia water storage system. [Background technology]

[0002] In recent years, from the perspective of environmental conservation, zero emissions have been proposed to reduce the discharge of environmentally polluting substances and waste. In the field of international shipping, ammonia has also attracted attention as a fuel that does not produce carbon dioxide (CO2) when burned, and the development of ammonia-fueled ships is underway (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-161921 Summary of the Invention [Problem to be solved by the invention]

[0004] For ammonia-fueled ships, the boiling point of ammonia is as low as -33°C under atmospheric pressure, so the idea of ​​storing ammonia on board as liquefied ammonia at low temperature or high pressure is being considered. If liquefied ammonia leaks into the atmosphere, the vaporized ammonia gas will spread. Because ammonia gas is highly toxic, preventing liquefied ammonia leaks and minimizing the impact on humans and the environment in the event of a leak are important issues.

[0005] The present invention has been devised in view of the above problems, and aims to provide an ammonia water storage system and an ammonia-fueled ship that can reduce the impact of ammonia leakage on the human body and the environment. [Means for solving the problem]

[0006] According to the present invention, An ammonia water storage system to be installed on an ammonia-fueled ship, the ammonia fuel tank storing ammonia as fuel in a liquefied state, and an ammonia-fueled engine burning the ammonia to generate power, The ammonia water storage system includes an ammonia water storage tank for storing ammonia gas or ammonia water generated on board a ship in the form of ammonia water, a recovery line for transporting the ammonia gas or the ammonia water to the ammonia water storage tank, a water supply line for supplying seawater to the ammonia water storage tank, a drain line for discharging the ammonia water stored in the ammonia water storage tank overboard, and a concentration meter for measuring the concentration of the ammonia water.

[0007] The ammonia water storage tank may be configured to also serve as a ballast tank.

[0008] A plurality of the ammonia water storage tanks may be arranged in the longitudinal direction of the ship.

[0009] The inner surface of the ammonia water storage tank may be coated with an anti-corrosion paint.

[0010] The ammonia water storage tank may include an air vent pipe and a pressure adjustment mechanism.

[0011] The recovery line is, for example, a line for transporting ammonia water generated on board the ship, a purge gas containing the ammonia gas, or ammonia water generated in the course of a purge treatment.

[0012] The drain line may be provided with an ammonia neutralizer capable of adjusting the concentration of the ammonia water.

[0013] The ammonia neutralization device may also be disposed within the ballast water treatment device.

[0014] The drain line may include a control valve that controls drainage of the ammonia water based on the concentration of the ammonia water.

[0015] The ammonia water storage system may include a control device that controls the supply of seawater to the ammonia water storage tank based on the measurement value of the concentration meter.

[0016] The concentration meter may be disposed in the ammonia water storage tank, in the recovery line, or in the drain line.

[0017] Furthermore, according to the present invention, there is provided an ammonia-fueled ship that uses ammonia as fuel, characterized in that it includes an ammonia-water storage system having any of the above-described configurations. [Effects of the Invention]

[0018] According to the above-described ammonia water storage system and ammonia-fueled ship of the present invention, ammonia that leaks or is generated on board the ship can be stored, and the impact of ammonia leakage on the human body and the environment can be reduced. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram showing a configuration of an ammonia water storage system according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram of an ammonia-fueled ship. [Figure 3] 1A and 1B are diagrams showing examples of the arrangement of an ammonia water storage tank, where (A) shows a first example and (B) shows a second example. [Figure 4] FIG. 2 is an explanatory diagram of a water supply system for an ammonia water storage tank. [Figure 5] FIG. 2 is an explanatory diagram of a drainage system of an ammonia water storage tank. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 5. Fig. 1 is a diagram showing the configuration of an ammonia water storage system according to one embodiment of the present invention. Fig. 2 is a schematic diagram of an ammonia-fueled ship. Fig. 3 is a diagram showing an example of the arrangement of an ammonia water storage tank, where (A) shows a first example and (B) shows a second example.

[0021] As shown in FIG. 1, an ammonia water storage system 1 according to one embodiment of the present invention includes an ammonia water storage tank 2 for storing ammonia gas or ammonia water generated on board a ship in the form of ammonia water, a recovery line 3 for transporting ammonia gas or ammonia water to the ammonia water storage tank 2, a water supply line 4 for supplying seawater to the ammonia water storage tank 2, a drainage line 5 for discharging the ammonia water stored in the ammonia water storage tank 2 overboard, a concentration meter 6 for measuring the concentration of the ammonia water stored in the ammonia water storage tank 2, and a control device 7 for controlling the supply of seawater to the ammonia water storage tank 2 based on the measurement value of the concentration meter 6.

[0022] Such an ammonia water storage system 1 is mounted on, for example, an ammonia-fueled ship 8 shown in Fig. 2. The ammonia-fueled ship 8 is a ship that uses ammonia as fuel to obtain propulsion power for its hull.

[0023] The ammonia-fueled ship 8 includes, for example, an ammonia fuel tank 81 that stores ammonia as fuel, a reliquefaction device 82 that reliquefies vaporized gas generated from the ammonia fuel tank 81, an ammonia-fueled engine 83 that burns ammonia to generate power, a fuel supply device 84 that supplies ammonia from the ammonia fuel tank 81 to the ammonia-fueled engine 83, and a bunker station 85 that supplies ammonia to the ammonia fuel tank 81.

[0024] The configuration of the ammonia-fueled ship 8 shown in Fig. 2 is merely an example, and is not limited to the configuration and arrangement shown. The ammonia-fueled ship 8 may also be a hybrid ship that uses other propulsion equipment such as a diesel engine and an electric motor in combination. The ammonia-fueled ship 8 may also be one that employs a multi-fuel engine that switches between multiple fuels.

[0025] The ammonia water storage tank 2 is a tank mounted on the ammonia-fueled ship 8. The ammonia water storage tank 2 shown in FIG. 3(A) is configured as a dedicated tank for storing only ammonia water. The ammonia water storage tank 2 is arranged, for example, near the accommodation area 86. Note that the number, arrangement, shape, etc. of the ammonia water storage tanks 2 are not limited to the configuration shown in the figure.

[0026] The ammonia-fueled ship 8 is also equipped with ballast tanks 87 that can inject and discharge ballast water (seawater) to adjust the draft, inclination, etc. of the hull. The ballast tanks 87 include, for example, a first ballast tank 87a arranged along the bottom of the ship, a second ballast tank 87b (topside tank) arranged along the side of the upper part of the hold, and a third ballast tank 87c arranged at the stern. Note that the arrangement of the ballast tanks 87 differs depending on the type of ship and is not limited to the arrangement shown in the figure.

[0027] The first ballast tank 87a and the second ballast tank 87b are divided into multiple sections along the length of the ship, and each section is configured to be able to inject or discharge ballast water. The third ballast tank 87c is configured to be able to inject or discharge ballast water separately from the first ballast tank 87a and the second ballast tank 87b.

[0028] However, assuming that a large amount of ammonia water will be generated or that the ammonia water will be stored for a long period of time, it is predicted that the required capacity of the ammonia water storage tank 2 will increase and adjustment of the hull attitude will also be necessary. Therefore, as shown in Figure 3(A), if the ammonia water storage tank 2 is a dedicated tank, there will be a limit to the amount of ammonia water that can be stored.

[0029] The ammonia water storage tank 2 shown in Fig. 3(B) is configured so that the ammonia water storage tank 2 also serves as a ballast tank 87. The ammonia water storage tank 2 is disposed in a part of the ballast tank 87. In Fig. 3(B), for ease of explanation, the tank of the ballast tank 87 that is also used as the ammonia water storage tank 2 is shown shaded gray.

[0030] The ammonia water storage tanks 2 are arranged, for example, on the bow and stern sides of the first ballast tank 87a and in the third ballast tank 87c. By arranging a plurality of ammonia water storage tanks 2 in the longitudinal direction of the ship, ammonia water can be stored in a balanced manner. It is optional which tanks among the ballast tanks 87 are used also as ammonia water storage tanks 2, and the arrangement is not limited to that shown in the figure.

[0031] The inner surface of the ammonia water storage tank 2 is coated with an anti-corrosion paint, whether it is a dedicated tank or a dual-purpose tank. The paint used is one that is resistant to the ammonia water solution.

[0032] 1, the ammonia water storage tank 2 is equipped with an air vent pipe 21 and a pressure adjustment mechanism 22. The air vent pipe 21 is a pipe for venting air from the tank when collecting ammonia water or when supplying seawater. The air vent pipe 21 may be equipped with an on-off valve 23.

[0033] Closing the on-off valve 23 makes it possible to suppress the diffusion of ammonia gas (boil-off gas) outside the tank when the ammonia water is stored. Note that the on-off valve 23 is opened when the ammonia water is recovered or seawater is supplied.

[0034] The pressure adjustment mechanism 22 is, for example, a breather valve or a vent post. The pressure adjustment mechanism 22 is a device for suppressing excessive negative pressure in the ammonia water storage tank 2 when the on-off valve 23 is closed.

[0035] The recovery line 3 includes, for example, a first recovery line 31 that transports ammonia water generated on board the ship, a second recovery line 32 that transports purge gas containing ammonia gas, and a third recovery line 33 that transports ammonia water generated during the purge process.

[0036] There is a possibility of ammonia gas leaking from each of the equipment constituting the ammonia-fueled ship 8 shown in Fig. 2, such as the ammonia fuel tank 81, reliquefaction unit 82, ammonia-fueled engine 83, fuel supply equipment 84, bunker station 85, and the piping connecting these. As a means of preventing the spread of leaked ammonia gas, it is conceivable to install a water spray 34 that sprays water at leakage target points 88 that may leak.

[0037] The sprayed water (ammonia water) that has absorbed the ammonia gas is collected by collection means 35, such as a drip tray or a drain outlet, installed at the leakage target location 88. The ammonia water collected by the collection means 35 is transported to the ammonia water storage tank 2 via a first collection line 31. The first collection line 31 may be provided with a filter 31a that removes foreign matter and an on-off valve 31b that controls the transport of the ammonia water.

[0038] In addition, in the ammonia fuel system, bunkering system, and constituent equipment of the ammonia-fueled ship 8, purging treatment with nitrogen gas is required to remove and block ammonia fuel when the equipment is stopped (including in the case of an emergency stop), when fuel is switched in a multi-fuel engine, during maintenance, etc.

[0039] If the high concentration ammonia gas pushed out by these purging processes were directly released overboard, it could have an adverse effect on the human body and the environment, so it is temporarily stored in the ammonia water storage tank 2. The second recovery line 32 is a route for transporting the ammonia gas to the ammonia water storage tank 2, and the third recovery line 33 is a route for transporting the ammonia gas to the ammonia water storage tank 2.

[0040] In this embodiment, the paths for the purge gas and the ammonia gas during the purging process are distinguished, but the second recovery line 32 and the third recovery line 33 may be the same path or may be joined along the way. Also, the ammonia gas contained in the purge gas may be converted into ammonia water before being transported to the ammonia water storage tank 2.

[0041] The water supply line 4 is a path for supplying seawater from a seawater inlet 41 (sea chest) and transporting it to the ammonia water storage tank 2. The concentration of the ammonia water (hydrogen ion exponent pH) is adjusted by supplying seawater to the ammonia water storage tank 2. The water supply line 4 includes, for example, a ballast pump 42 that draws in and transports seawater, a filter 43 that removes foreign matter that has been drawn in, and an on-off valve 44 that controls the opening and closing of the seawater inlet 41.

[0042] The water supply line 4 may be equipped with a ballast water treatment device 46 arranged in the bypass line 45. The ballast water treatment device 46 is a device that kills or inactivates harmful aquatic organisms and pathogens contained in the intake seawater (ballast water). Switching valves 47 and 48 for switching paths are arranged in the water supply line 4 and the bypass line 45, respectively. In addition, the water supply line 4 is equipped with a switching valve 49 for switching between the water supply system and the drainage system.

[0043] The drain line 5 is a path for discharging the ammonia water stored in the ammonia water storage tank 2 overboard at sea. The drain line 5 is equipped with, for example, a concentration meter 51 that measures the concentration (hydrogen ion exponent pH) of the ammonia water to be discharged, and a control valve 52 that controls the discharge of the ammonia water. When the measurement value of the concentration meter 51 exceeds a set concentration threshold, the control valve 52 is closed. Note that when the concentration meter 51 is omitted, the control valve 52 may be controlled based on the measurement value of the concentration meter 6.

[0044] The drain line 5 may also be equipped with an ammonia neutralizer 53 capable of adjusting the concentration (hydrogen ion exponent pH) of the ammonia water. The ammonia neutralizer 53 adjusts the concentration (hydrogen ion exponent pH) of the ammonia water by injecting a neutralizing agent into the ammonia water. The ammonia neutralizer 53 is disposed, for example, inside the ballast water treatment device 46.

[0045] The drain line 5 may also include a bypass line 54 for draining the ammonia water via the ballast pump 42 and a switching valve 55 for controlling the opening and closing of the bypass line 54.

[0046] 4 is an explanatory diagram of the water supply system of the ammonia water storage tank. During water supply, the control valve 52 and the switching valve 55 are set to close, and the on-off valve 44 and the switching valve 49 are set to open.

[0047] When the ballast water treatment device 46 is not used, the switching valve 47 is set to open and the switching valve 48 is set to close. Then, by operating the ballast pump 42, seawater is supplied to the ammonia water storage tank 2 through the first water supply path La that passes through the seawater inlet 41, the filter 43, and the ballast pump 42.

[0048] When the ballast water treatment device 46 is used, the switching valve 47 is set to close and the switching valve 48 is set to open. Then, the ballast pump 42 is operated to supply seawater to the ammonia water storage tank 2 through the second water supply path Lb that passes through the seawater inlet 41, the filter 43, the ballast pump 42, and the ballast water treatment device 46.

[0049] 5 is an explanatory diagram of the drainage system of the ammonia water storage tank. During drainage, the on-off valve 44 and the switching valve 49 are set to closed, and the control valve 52 and the switching valve 55 are set to open. When the concentration of ammonia water in the ammonia water storage tank 2 is equal to or lower than the concentration at which the ammonia water can be discharged overboard, the ammonia water can be discharged outside without using the ammonia neutralization device 53.

[0050] When the ammonia neutralization device 53 is not used, the switching valve 47 is set to open and the switching valve 48 is set to close. Thereafter, the ballast pump 42 is operated to discharge the ammonia water from the ammonia water storage tank 2 to the outside through the first drainage path Lc that passes through the filter 43 and the ballast pump 42.

[0051] When the ammonia neutralization device 53 is used, the switching valve 47 is set to close and the switching valve 48 is set to open. Thereafter, the ballast pump 42 is operated to discharge the ammonia water from the ammonia water storage tank 2 to the outside through the second drainage path Ld that passes through the ammonia neutralization device 53, the filter 43, and the ballast pump 42.

[0052] As shown in Fig. 1, the ammonia water storage tank 2 may be provided with a landing line 56 for unloading the stored ammonia water when the ship is anchored, etc. For the sake of convenience of explanation, the landing line 56 is omitted from Figs. 4 and 5. The landing line 56 is included in the term "discharge line" in this embodiment. When unloading the ammonia water, the ammonia water is stored in a tank or the like arranged on land, so there is little need to reduce the concentration of the ammonia water to a level that allows it to be discharged overboard.

[0053] The concentration meter 6 is a sensor that monitors the concentration of the ammonia water stored in the ammonia water storage tank 2. The concentration meter 6 is, for example, a sensor that measures the hydrogen ion exponent pH of the ammonia water. The concentration meter 6 is disposed, for example, at the bottom of the ammonia water storage tank 2. The concentration meter 6 may be disposed in the recovery line 3 that serves as the inlet of the ammonia water storage tank 2, or in the drainage line 5 that serves as the outlet of the ammonia water storage tank 2.

[0054] The control device 7 is a device that controls the water supply system so as to dilute the ammonia water stored in the ammonia water storage tank 2 based on the measurement value of the concentration meter 6. The control device 7 is set with, for example, a threshold value for reducing corrosion of the ammonia water storage tank 2 and a threshold value for discharging the ammonia water overboard, and when the predetermined threshold value is exceeded, seawater is supplied into the ammonia water storage tank 2 using the water supply line 4. The control device 7 may be incorporated into a ballast water control device.

[0055] As shown in Figure 3(B), when the ammonia water storage tank 2 also serves as a ballast tank 87, seawater (ballast water) may be supplied to adjust the hull posture regardless of the measurement value of the concentration meter 6.

[0056] According to the ammonia water storage system 1 and the ammonia-fueled ship 8 according to the present embodiment described above, ammonia that has leaked or been generated on board the ship can be collected and stored in the form of ammonia water, thereby reducing the impact of ammonia leakage on the human body and the environment.

[0057] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0058] 1. Ammonia water storage system 2. Ammonia water storage tank 3. Collection line 4. Water supply line 5. Drainage line 6 Densitometer 7 Control Device 8. Ammonia-fueled ships 21 Air vent pipe 22 Pressure adjustment mechanism 23 On-off valve 31 First Recovery Line 31a filter 31b On-off valve 32 Second Recovery Line 33 Third Recovery Line 34 Water Spray 35 Recovery Methods 41 Seawater intake 42 Ballast pump 43 Filters 44 On-off valve 45 Bypass Line 46 Ballast Water Treatment System 47, 48, 49, 55 Switching valve 51 Densitometer 52 Control valve 53 Ammonia Neutralizer 54 Bypass Line 56 Landing line 81 Ammonia Fuel Tank 82 Reliquefaction equipment 83 Ammonia-fueled engine 84 Fuel supply equipment 85 Bunker Station 86 Residential area 87 Ballast Tank 87a First Ballast Tank 87b Second Ballast Tank 87c Third ballast tank 88 Leakage target area

Claims

1. An ammonia water storage system to be installed on an ammonia-fueled ship, the system including an ammonia fuel tank for storing ammonia in a liquefied state as fuel, and an ammonia-fueled engine for generating power by burning the ammonia, an ammonia water storage tank for storing ammonia gas or ammonia water generated on board in the form of ammonia water; a recovery line for transporting the ammonia gas or the ammonia water to the ammonia water storage tank; a water supply line for supplying seawater to the ammonia water storage tank; a drainage line for discharging the ammonia water stored in the ammonia water storage tank outside the ship; a concentration meter for measuring the concentration of the ammonia water; An ammonia water storage system comprising:

2. The ammonia water storage system according to claim 1 , wherein the ammonia water storage tank is configured to also serve as a ballast tank.

3. The ammonia water storage system according to claim 2 , wherein a plurality of the ammonia water storage tanks are arranged in the longitudinal direction of the ship.

4. 2. The ammonia water storage system according to claim 1, wherein the inner surface of the ammonia water storage tank is coated with a coating for corrosion prevention.

5. 2. The ammonia water storage system according to claim 1, wherein the ammonia water storage tank is provided with an air vent pipe and a pressure adjustment mechanism.

6. 2. The ammonia water storage system according to claim 1, wherein the recovery line is a line for transporting ammonia water generated on board a ship, a purge gas containing the ammonia gas, or ammonia water generated during a purge process.

7. The ammonia water storage tank according to claim 1 , wherein the drain line is provided with an ammonia neutralizer capable of adjusting the concentration of the ammonia water.

8. The ammonia water storage tank according to claim 7 , wherein the ammonia neutralization device is disposed in a ballast water treatment device.

9. 2. The ammonia water storage tank according to claim 1, wherein the drain line includes a control valve that controls drainage of the ammonia water based on the concentration of the ammonia water.

10. 2. The ammonia water storage tank according to claim 1, further comprising a control device that controls the supply of seawater to the ammonia water storage tank based on the measurement value of the concentration meter.

11. The ammonia water storage tank according to claim 1 , wherein the concentration meter is disposed in the ammonia water storage tank, the recovery line, or the drain line.

12. 12. An ammonia-fueled ship that uses ammonia as fuel, comprising the ammonia water storage system according to any one of claims 1 to 11.

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