Apparatus and method for treating ammonia gas

Abstract

The present invention addresses the problem of providing an apparatus and a method for treating ammonia gas, with which it is possible to safely store ammonia water having ammonia gas dissolved therein and with which it is also possible to reduce storage space. This problem is solved by an apparatus for treating ammonia gas, the apparatus being characterized in that, in a ship carrying liquefied ammonia as cargo or fuel, a detoxification device 6 is used to obtain ammonia gas volatilized from the cargo or ammonia gas generated as the result of the vaporization of liquefied ammonia remaining in a fuel supply line 2, 4 and / or for dissolving the ammonia gas in clean water, and is provided with a water sealing tank 12 in which the ammonia gas is dissolved in stored clean water and a scrubber 13 in which clean water is sprayed into the ammonia gas discharged from the water sealing tank 12 to dissolve the ammonia gas in the clean water.

Description

Ammonia gas treatment device and treatment method

[0001] The present invention relates to an ammonia gas treatment device and treatment method for a ship carrying liquefied ammonia as cargo or engine fuel, and more particularly to an ammonia gas treatment device and treatment method that can safely store ammonia gas obtained by vaporizing liquefied ammonia that has evaporated from cargo or remained in an engine fuel supply line and / or ammonia water obtained by dissolving ammonia gas in fresh water, and that can reduce storage space.

[0002] In response to the recent global warming issue, the use of liquefied ammonia as fuel for marine propulsion engines is being considered. When liquefied ammonia is used as fuel, it is necessary to empty the fuel supply system in order to purge the fuel pipes and to keep the temperature within the flammable range in the event of an emergency. Furthermore, in tanks that store ammonia, ammonia gas known as boil-off gas is generated due to natural heat input, etc. If ammonia gas is allowed to generate, the pressure inside the tank will rise and exceed the design pressure, and it must be treated by releasing it into the atmosphere, etc.

[0003] However, ammonia gas is flammable and toxic, and therefore, if released directly into the atmosphere, it will have an adverse effect on the human body. Therefore, it is necessary to remove ammonia gas from exhaust gas released into the atmosphere using a detoxification device. Patent Document 1 describes a detoxification device that dissolves ammonia gas in clean water and recovers it as ammonia water.

[0004] Patent No. 6934555

[0005] The treated water (ammonia water) in which ammonia gas is dissolved in fresh water in the detoxification device cannot be discharged overboard due to emission regulations, so the treated water must be stored or treated on board. If the treated water is stored on board, it is preferable to use a small storage tank to reduce the storage space.

[0006] Therefore, an object of the present invention is to provide an ammonia gas treatment device and treatment method that can safely store ammonia gas formed by vaporizing liquefied ammonia that has evaporated from cargo or remained in an engine fuel supply line and / or ammonia water formed by dissolving ammonia gas in fresh water, and that can reduce storage space.

[0007] Further objects of the present invention will become apparent from the following description.

[0008] The above problems are solved by the following inventions: 1. An ammonia gas treatment device for a ship carrying liquefied ammonia as cargo or engine fuel, comprising a detoxification device that dissolves ammonia gas and / or ammonia gas formed by vaporization of liquefied ammonia that has evaporated from the cargo or remained in the engine fuel supply line into fresh water to produce ammonia water, the detoxification device comprising: a water seal tank in which fresh water is stored, into which the ammonia gas formed by vaporization of liquefied ammonia and / or the ammonia gas is introduced from a lower part, and the ammonia gas is dissolved in the stored fresh water to produce ammonia water; and a scrubber into which ammonia gas discharged from an upper part of the water seal tank is introduced at a lower part and into which fresh water is supplied at an upper part, and the ammonia gas is dissolved in the fresh water to produce ammonia water. 2. The ammonia gas treatment device according to item 1, characterized in that the detoxification device has a circulation pump that sends ammonia water in the scrubber to an upper part of the scrubber. 3. 3. The ammonia gas treatment device according to claim 2, characterized in that the ammonia gas detoxification device has a concentration meter through which the ammonia water sent to the upper part of the scrubber passes. 4. The ammonia gas treatment device according to claim 3, characterized in that the ammonia water detoxification device has a circulation on-off valve through which the ammonia water sent to the upper part of the scrubber passes, and a scrubber drain valve through which the ammonia water sent from the scrubber to a treated water storage tank passes, and continues to send the ammonia water in the scrubber to the upper part of the scrubber until the concentration of the ammonia water detected by the concentration meter reaches a desired concentration. 5. The ammonia gas treatment device according to claim 2, characterized in that the ammonia gas detoxification device has an uninterruptible power supply that drives the circulation pump, and in the event of a loss of power supply for driving the circulation pump, the circulation pump can be driven by the uninterruptible power supply. 6. The ammonia gas treatment device according to claim 2, characterized in that the ammonia water detoxification device has a heat exchanger that cools the ammonia water sent to the upper part of the scrubber by the circulation pump.7. The ammonia gas treatment device according to any one of 1 to 6, characterized in that it comprises a treated water storage tank for storing ammonia water, to which ammonia water produced in the detoxification device is sent, and ammonia gas volatilized from the treated water storage tank is introduced below the scrubber. 8. The ammonia gas treatment device according to any one of 1 to 6, characterized in that it comprises a treated water storage tank for storing ammonia water, to which ammonia water produced in the detoxification device is sent, and the treated water storage tank is a pressurized ammonia water storage tank. 9. The ammonia gas treatment device according to any one of 1 to 6, characterized in that it comprises a selective reduction catalyst unit to which exhaust gas from an engine of the ship is introduced, and the selective reduction catalyst unit is supplied with ammonia water produced in the detoxification device and performs denitrification treatment on the exhaust gas. 10. The ammonia gas treatment device according to any one of 1 to 5, characterized in that it comprises a neutralization treatment device to which ammonia water is sent from the detoxification device, and the neutralization treatment device neutralizes the ammonia water with an acidic neutralizing agent to produce neutralized water. 11. 11. The ammonia gas treatment device according to claim 10, further comprising a selective catalytic reduction unit into which exhaust gas from an engine of the ship is introduced, wherein the selective catalytic reduction unit is supplied with neutralized water produced in the neutralization treatment device and performs denitrification treatment of the exhaust gas. 12. The ammonia gas treatment device according to any of claims 2 to 4, further comprising: a fresh water tank for storing the fresh water, which is sent to a pressurized buffer tank for storage, and which is supplied to an upper part of the scrubber by the pressure in the pressurized buffer tank in the event of a loss of power supply for driving the circulation pump. 13. The ammonia gas treatment device according to claim 12, further comprising: a pressure source for ammonia gas vaporized from liquefied ammonia remaining in the fuel supply line and / or an inert gas pressure source for purging ammonia gas and sending it to the abatement device.14. The ammonia gas treatment device according to claim 2, further comprising: a heat exchanger that cools the ammonia water sent to an upper part of the scrubber by the circulation pump; and a neutralization treatment device to which the ammonia water is sent from the detoxification device, the neutralization treatment device neutralizing the ammonia water with an acidic neutralizing agent to produce neutralized water; and a selective reduction catalyst unit to which exhaust gas from an engine of the ship is introduced, the selective reduction catalyst unit being supplied with the neutralized water produced in the neutralization treatment device and performing denitrification treatment of the exhaust gas. 15. The ammonia gas treatment device according to claim 14, further comprising: an uninterruptible power supply that drives the circulation pump, and in the event of a loss of power supply that drives the circulation pump, the circulation pump can be driven by the uninterruptible power supply. 16. 16. The ammonia gas treatment device according to claim 2, further comprising: a heat exchanger that cools the ammonia water sent to the upper part of the scrubber by the circulation pump; the fresh water is sent to and stored in a pressurized buffer tank from a fresh water tank that stores the fresh water, and is supplied to the upper part of the scrubber by the pressure in the pressurized buffer tank when power to drive the circulation pump is lost; and the pressurized buffer tank is pressurized by a pressure source of ammonia gas formed by vaporization of liquefied ammonia remaining in the fuel supply line and / or an inert gas that purges the ammonia gas and sends it to the abatement device. 17. The ammonia gas treatment device according to claim 14, 15, or 16, further comprising: a treated water storage tank that stores the ammonia water and receives the ammonia water produced in the abatement device; and ammonia gas vaporized from the treated water storage tank is introduced to the lower part of the scrubber. 17. The ammonia gas treatment device according to claim 14, 15 or 16, further comprising a treated water storage tank for storing the ammonia water produced by the ammonia removal device, wherein the treated water storage tank is a pressurized ammonia water storage tank.19. The ammonia gas treatment device according to any one of claims 14, 15, or 16, comprising a selective reduction catalyst unit into which exhaust gas from an engine of the ship is introduced, wherein the selective reduction catalyst unit is supplied with ammonia water produced in the abatement device and performs denitration treatment of the exhaust gas. 20. The ammonia gas treatment device according to claim 16, comprising a neutralization treatment device to which ammonia water is sent from the abatement device, wherein the neutralization treatment device neutralizes the ammonia water with an acidic neutralizing agent to produce neutralized water. 21. The ammonia gas treatment device according to claim 20, comprising a selective reduction catalyst unit into which exhaust gas from an engine of the ship is introduced, wherein the selective reduction catalyst unit is supplied with neutralized water produced in the neutralization treatment device and performs denitration treatment of the exhaust gas. 22. 22. A method for treating ammonia gas on a ship carrying liquefied ammonia as cargo or engine fuel, comprising: sending ammonia gas and / or ammonia gas formed by vaporization of liquefied ammonia that has evaporated from the cargo or remained in the engine fuel supply line to a detoxification device, the detoxification device comprising: a water seal tank in which fresh water is stored, and into which the ammonia gas formed by vaporization of the liquefied ammonia and / or the ammonia gas is introduced from a lower part and the ammonia gas is dissolved in the stored fresh water to form ammonia water; and a scrubber into which ammonia gas discharged from an upper part of the water seal tank is introduced to a lower part and fresh water is supplied to an upper part and the ammonia gas is dissolved in the fresh water to form ammonia water, the method comprising: dissolving the ammonia gas formed by vaporization of the liquefied ammonia and / or the ammonia gas in the detoxification device. 23. The method for treating ammonia gas according to paragraph 22, characterized in that the ammonia gas is provided with a circulation pump in the detoxification device, and the ammonia water in the scrubber is sent to an upper part of the scrubber by the circulation pump. 24. The method for treating ammonia gas according to 23, wherein the ammonia removal device is provided with a concentration meter, and the concentration meter measures the ammonia water that the circulation pump sends to the upper part of the scrubber.25. The method for treating ammonia gas according to claim 24, wherein the ammonia water in the scrubber is sent to the upper part of the scrubber until the concentration of the ammonia water detected by the concentration meter reaches a desired concentration. 26. The method for treating ammonia gas according to claim 23, wherein an uninterruptible power supply is provided to drive the circulation pump, and when the power supply to drive the circulation pump is lost, the circulation pump can be driven by the uninterruptible power supply. 27. The method for treating ammonia gas according to claim 23, wherein a heat exchanger is provided in the ammonia treatment device, and the heat exchanger cools the ammonia water sent by the circulation pump to the upper part of the scrubber. 28. The method for treating ammonia gas according to any of claims 22 to 27, wherein a treated water storage tank is provided, and ammonia water produced by the ammonia treatment device is sent to the treated water storage tank for storage, and ammonia gas volatilized from the treated water storage tank is introduced into the lower part of the scrubber. 29. 28. The method for treating ammonia gas as set forth in any of paragraphs 22 to 27, further comprising: providing a treated water storage tank which is a pressurized ammonia water storage tank; and sending the ammonia water produced by the detoxification device to the treated water storage tank for storage. 30. The method for treating ammonia gas as set forth in any of paragraphs 22 to 27, further comprising: providing a selective reduction catalyst unit; and supplying exhaust gas from the ship's engine and the ammonia water produced by the detoxification device to the selective reduction catalyst unit, and performing denitrification treatment of the exhaust gas. 31. The method for treating ammonia gas as set forth in any of paragraphs 22 to 26, further comprising: providing a neutralization treatment device; and supplying the ammonia water produced by the detoxification device and an acidic neutralizing agent to the neutralization treatment device, and neutralizing the ammonia water to produce neutralized water. 32. 32. The method for treating ammonia gas according to claim 31, further comprising providing a selective catalytic reduction unit, supplying the exhaust gas from the engine of the ship and the neutralized water produced by the neutralization treatment device to the selective catalytic reduction unit, and performing denitration treatment of the exhaust gas.33. The method for treating ammonia gas according to any one of paragraphs 23 to 25, further comprising providing a pressurized buffer tank, sending the fresh water to the pressurized buffer tank for storage, and supplying the fresh water to the top of the scrubber by the pressure in the pressurized buffer tank in the event of a loss of power to drive the circulation pump. 34. The method for treating ammonia gas according to paragraph 33, further comprising pressurizing the inside of the pressurized buffer tank by a pressure source of ammonia gas vaporized from liquefied ammonia remaining in the fuel supply line and / or an inert gas that purges the ammonia gas and sends it to the abatement device. 35. 35. The method for treating ammonia gas according to claim 23, wherein the decontamination device has a heat exchanger that cools the ammonia water sent to the upper part of the scrubber by the circulation pump, and is provided with a neutralization treatment device, wherein the ammonia water produced by the decontamination device and an acidic neutralizing agent are supplied to the neutralization treatment device to neutralize the ammonia water to produce neutralized water, and wherein a selective reduction catalyst unit is provided, and wherein exhaust gas from an engine of the ship and the neutralized water produced by the neutralization treatment device are supplied to the selective reduction catalyst unit to denitrify the exhaust gas. 36. The method for treating ammonia gas according to claim 35, wherein an uninterruptible power supply is provided to drive the circulation pump, and when the power supply for driving the circulation pump is lost, the circulation pump can be driven by the uninterruptible power supply. 24. The method for treating ammonia gas described in 23, wherein the ammonia detoxification device has a heat exchanger that cools the ammonia water sent to the upper part of the scrubber by the circulation pump, and is provided with a pressurized buffer tank, the fresh water is sent to the pressurized buffer tank for storage, and in the event of a loss of power supply for driving the circulation pump, the fresh water is supplied to the upper part of the scrubber by the pressure in the pressurized buffer tank, and the inside of the pressurized buffer tank is pressurized by a pressure source of ammonia gas vaporized from liquefied ammonia remaining in the fuel supply line and / or an inert gas that purges the ammonia gas and sends it to the ammonia detoxification device.38. The method for treating ammonia gas as set forth in any one of claims 35, 36, or 37, characterized by providing a treated water storage tank, sending the ammonia water produced by the detoxification device to the treated water storage tank for storage, and introducing ammonia gas vaporized from the treated water storage tank into a lower portion of the scrubber. 39. The method for treating ammonia gas as set forth in any one of claims 35, 36, or 37, characterized by providing a treated water storage tank that is a pressurized ammonia water storage tank, and sending the ammonia water produced by the detoxification device to the treated water storage tank for storage. 40. The method for treating ammonia gas as set forth in any one of claims 35, 36, or 37, characterized by providing a selective reduction catalyst unit, supplying exhaust gas from an engine of the ship and the ammonia water produced by the detoxification device to the selective reduction catalyst unit, and performing denitrification treatment on the exhaust gas. 41. 41. The method for treating ammonia gas according to claim 37, further comprising: providing a neutralization treatment device, supplying the ammonia water produced by the detoxification device and an acidic neutralizing agent to the neutralization treatment device, and neutralizing the ammonia water to produce neutralized water. 42. The method for treating ammonia gas according to claim 41, further comprising: providing a selective reduction catalyst unit, supplying the selective reduction catalyst unit with exhaust gas from an engine of the ship and neutralized water produced by the neutralization treatment device, and performing denitrification treatment on the exhaust gas.

[0009] According to the present invention, it is possible to provide an ammonia gas treatment device and treatment method that can safely store ammonia gas formed by vaporizing liquefied ammonia that has evaporated from cargo or remained in an engine fuel supply line and / or ammonia water formed by dissolving ammonia gas in fresh water, and that can reduce storage space.

[0010] 1 is a block diagram showing the configuration of an ammonia gas treatment device according to a first embodiment of the present invention; 2 is a block diagram showing the configuration of an ammonia gas treatment device according to an improved embodiment (1) of the first embodiment of the present invention; 3 is a block diagram showing the configuration of an ammonia gas treatment device according to an improved embodiment (3) of the first embodiment of the present invention; and 4 is a block diagram showing the configuration of an ammonia gas treatment device according to a second embodiment of the present invention.

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Various features shown in each of the following embodiments can be combined with each other. The present invention is an ammonia gas treatment device for a ship that carries liquefied ammonia as cargo or fuel for the ship's engine, and an ammonia gas treatment method performed in this ammonia gas treatment device.

[0012] The present invention enables safe storage of ammonia gas obtained by vaporizing liquefied ammonia that has evaporated from cargo or remained in a fuel supply line and / or ammonia water obtained by dissolving ammonia gas in fresh water, and also enables reduction of storage space.

[0013] [First embodiment] [Device configuration] Fig. 1 is a block diagram showing the configuration of an ammonia gas treatment device according to a first embodiment of the present invention. An ammonia gas treatment method according to the first embodiment of the present invention is carried out by this ammonia gas treatment device. In Fig. 1, liquid flow paths are indicated by solid lines, and gas flow paths are indicated by dotted lines. This also applies to other drawings described later.

[0014] As shown in FIG. 1 , the ammonia gas treatment device of this embodiment treats ammonia gas obtained by vaporizing liquefied ammonia and / or ammonia gas (residual gas) introduced from a fuel supply line that supplies liquefied ammonia fuel from a liquefied ammonia tank 1 to an engine 3, which is an engine of a ship, or ammonia gas (boil-off gas) introduced from a cargo ammonia tank (not shown).

[0015] The fuel supply line is made up of the fuel supply device 2 and the fuel piping 4, and is a path for supplying liquefied ammonia fuel to the engine 3 via the fuel piping 4 by a compressor, a pump, a heat exchanger, etc., provided in the fuel supply device 2. Note that the fuel supply device 2 does not have to be provided if it is unnecessary. Furthermore, the fuel piping 4 may be made up of a supply piping that supplies ammonia gas from the fuel supply device 2 to the engine 3, and a return piping that returns excess ammonia gas from the engine 3 to the fuel supply device 2. Although not shown, on the liquefied ammonia tank 1 side of the fuel supply device 2 and the engine 3 side of the fuel piping 4, on-off valves that can close the section between the liquefied ammonia tank 1 side of the fuel supply device 2 and the engine 3 side of the fuel piping 4 may be provided.

[0016] Liquefied ammonia tank 1 stores ammonia, which is a fuel used for engine 3 and the like. Ammonia is stored as liquefied ammonia inside liquefied ammonia tank 1. In order to maintain the liquefied ammonia in a liquid state, the interior of liquefied ammonia tank 1 is maintained at high pressure or low temperature. When a large amount of liquefied ammonia is loaded onto a ship for a long voyage or the like, a full-refrigerated (atmospheric pressure) or semi-refrigerated (semi-pressurized) type liquefied ammonia tank 1 is mainly used, which has thin walls and is easy to process. A suction pump 1a is installed inside liquefied ammonia tank 1, and this suction pump 1a sends the stored liquefied ammonia to a pipe leading to fuel supply device 2.

[0017] The cargo ammonia tank stores liquefied ammonia as cargo, rather than fuel to be used for the engine 3, etc. As with the liquefied ammonia tank 1, the interior of the cargo ammonia tank is maintained at high pressure or low temperature in order to maintain the liquefied ammonia in a liquid state inside the cargo ammonia tank. When a large amount of liquefied ammonia is loaded onto a ship, the cargo ammonia tank mainly uses a full-refrigerated (atmospheric pressure) or semi-refrigerated (semi-pressurized) type, which has a thin wall and is easy to process.

[0018] Liquefied ammonia fuel is supplied to the engine 3 from a liquefied ammonia tank 1 by a fuel supply device 2. Pilot fuel may also be supplied to the engine 3 from a heavy oil tank (not shown). The pilot fuel is burned together with the ammonia fuel when the ammonia fuel starts to burn, raising the temperature inside the combustion chamber and ensuring good combustion of the ammonia fuel. The supply of pilot fuel may be stopped when the temperature inside the combustion chamber rises to a state where combustion using only ammonia fuel is possible. Furthermore, if the engine 3 is capable of burning only ammonia fuel from the start, pilot fuel is not necessary. Furthermore, the engine 3 may be a dual-fuel engine using liquefied ammonia fuel and a fossil fuel such as heavy oil. The dual-fuel engine can selectively switch between a mode in which liquefied ammonia fuel is supplied as the main fuel and a fossil fuel such as heavy oil is supplied as an ignition source, and a fossil fuel mode in which operation is performed using only fossil fuel.

[0019] Nitrogen gas is supplied to the fuel pipe 4 from a nitrogen gas supply device 11, which is a pressure source of inert gas, via a purge gas supply valve 10. This nitrogen gas is also supplied to the fuel supply device 2 via the fuel pipe 4. This nitrogen gas is an inert gas that purges ammonia gas and / or ammonia gas vaporized from liquefied ammonia remaining in the fuel pipe 4 and the fuel supply device 2 when the engine 3 is started, stopped, or emergency stopped.

[0020] Ammonia gas and / or ammonia gas vaporized from residual liquefied ammonia is introduced from the fuel pipe 4 to the detoxification device 6 via the gas-liquid separator 4a and the on-off valve 5 when the engine 3 is started, stopped, or stopped in an emergency. The ammonia gas and / or ammonia gas vaporized from residual liquefied ammonia is also introduced from the fuel supply device 2 to the detoxification device 6 via the on-off valve 2a when the engine 3 is started, stopped, or stopped in an emergency, or during maintenance. The fuel supply device 2 includes a gas-liquid separator at an outlet for the ammonia gas and / or ammonia gas vaporized from residual liquefied ammonia, along with a pump. The gas introduced from the fuel pipe 4 and the fuel supply device 2 to the detoxification device 6 is a mixture of ammonia gas and a purge gas, such as nitrogen. The treatment in this embodiment is performed on the ammonia component in the mixture. When ammonia gas is introduced into the detoxification device 6, the section between the liquefied ammonia tank 1 side of the fuel supply device 2 and the engine 3 side of the fuel pipe 4 is closed by an on-off valve. Ammonia gas (boil-off gas) is also introduced into the abatement device 6 from a cargo ammonia tank.

[0021] The detoxification device 6 is configured to include a water seal tank 12, a scrubber 13, and a circulation pump 14. The mixed gas of ammonia gas and nitrogen introduced into the detoxification device 6 is introduced into the lower part of the water seal tank 12. In the following, an embodiment will be described in which the scrubber 13 is a scrubber tank.

[0022] Fresh water is stored in the water seal tank 12, and a mixed gas of ammonia gas and nitrogen is introduced into it from the bottom. Here, fresh water is water that contains as few impurities and additives as possible, such as distilled water, ion-exchanged water, or filtered water. The bottom of the water seal tank 12 refers to the area below the surface of the fresh water in the water seal tank 12, and preferably refers to the bottom surface of the water seal tank 12 in order to increase the contact time between the fresh water in the water seal tank 12 and the ammonia gas.

[0023] The ammonia component of the mixed gas dissolves in the fresh water stored in the water seal tank 12, producing ammonia water. The water seal tank 12 is provided with a level gauge 12a. A mixed gas of ammonia gas that has not dissolved in the fresh water, ammonia gas that has volatilized from the ammonia water, and nitrogen is discharged from the top of the water seal tank 12. The top of the water seal tank 12 may be anywhere above the water surface of the ammonia water in the water seal tank 12.

[0024] Nitrogen gas can also be supplied to the bottom of the water seal tank 12 from the nitrogen gas supply device 11 via the pressure valve 11a. In the water seal tank 12, a certain amount of nitrogen gas is bubbled, thereby preventing freezing in winter and providing a dilution effect. Note that other inert gases or air can be used instead of nitrogen gas to prevent freezing. The dilution effect is achieved by adjusting the concentration of ammonia gas that has not dissolved in the clean water and ammonia gas that has evaporated from the ammonia water in the gas phase of the water seal tank 12 to a target concentration (for example, 25 mg / Nm3). ３ At the start of purging, 100% of the liquefied ammonia flows, and the contact rate between the fresh water and the mixed gas in the water seal tank 12 is not 100%, so if the gas phase volume of the water seal tank 12 is small, the unrecovered ammonia component will occupy the gas phase volume, and there is a possibility that the gas phase concentration will become 100%, so nitrogen gas is added to dilute it.

[0025] The gas mixture discharged from the top of the water tank 12 is introduced into the bottom of the scrubber tank 13. In the scrubber tank 13, fresh water is sprayed or dripped downward from the top, and the ammonia component of the gas mixture is dissolved in the sprayed or dripped fresh water to produce ammonia water. In consideration of extending the contact time between the fresh water and ammonia gas in the scrubber tank 13, the bottom of the scrubber tank 13 is preferably the bottom surface of the scrubber tank 13, and the top of the scrubber tank 13 is preferably the top surface of the scrubber tank 13. Note that porous or granular fillers may be placed inside the scrubber tank 13 to ensure good gas-liquid contact.

[0026] In the scrubber tank 13, nitrogen gas for purging is released into the atmosphere from the top. The nitrogen gas is supplied by the nitrogen gas supply device 11 at a discharge pressure sufficient to release the nitrogen gas from the top of the scrubber tank 13. This increases the efficiency with which ammonia gas not dissolved in the fresh water and ammonia gas volatilized from the ammonia water come into contact with the fresh water in the scrubber tank 13.

[0027] The circulation pump 14 returns the ammonia water from the lower part of the scrubber tank 13 to the upper part of the scrubber tank 13 via a concentration meter 13a, a heat exchanger 13b, and a circulation on-off valve 13c, which are located outside the scrubber tank 13. The heat exchanger 13b is supplied with seawater or a refrigerant and cools the ammonia water returned to the upper part of the scrubber tank 13 by the circulation pump 14. The refrigerant can be fresh water or a refrigerant cooled with seawater. The ammonia water returned to the upper part of the scrubber tank 13 is sprayed downward again. When ammonia gas is supplied to the scrubber tank 13, the ammonia water is cooled by the heat exchanger 13b, thereby suppressing the effects of reaction heat. Furthermore, lowering the temperature of the ammonia water increases the amount of ammonia components dissolved. This reduces the volume per ammonia component and reduces storage space. The concentration meter 13a may be replaced with a pH meter, density meter, conductivity meter, or the like. A flow meter (not shown) may be provided in the path of the ammonia water returned to the upper part of the scrubber tank 13 .

[0028] In this detoxification device 6, ammonia gas volatilized from the water seal tank 12 is recovered by the scrubber tank 13, so the ammonia gas can be safely treated. A large amount of ammonia gas volatilizes from the ammonia water, and treatment of this volatilized ammonia gas also becomes a problem, but the ammonia gas can be safely treated by the detoxification device 6 having the water seal tank 12, the scrubber tank 13, and the circulation pump 14.

[0029] The fresh water supplied to the water seal tank 12 and the scrubber tank 13 in the abatement system 6 may be generated by, for example, an onboard water generator and stored in the fresh water tank 22, or the fresh water may be stored in a tank in advance. The stored fresh water from the fresh water tank 22 is introduced into the abatement system 6 by a water supply pump 22a.

[0030] In this embodiment, the fresh water introduced into the abatement device 6 is branched into two parts, one of which is supplied to the water seal tank 12 via the water seal tank water supply valve 12b and the other to the upper part of the scrubber tank 13 via the scrubber tank water supply valve 13d. The supply pipe to the upper part of the scrubber tank 13 joins with a return pipe that runs from the lower part of the scrubber tank 13 through a circulation on-off valve 13c.

[0031] Wastewater (ammonia water) from the bottom of the water seal tank 12 is sent by a drain pump 12e through a water seal tank drain valve 12c and a concentration meter 12d to the treated water storage tank 7, where it is temporarily stored. The concentration meter 12d may be replaced with a pH meter, a density meter, a conductivity meter, or the like. Wastewater from the bottom of the scrubber tank 13 is sent by a circulation pump 14 through a concentration meter 13a and a heat exchanger 13b and a scrubber tank drain valve 13e to the treated water storage tank 7, where it is temporarily stored.

[0032] In this embodiment, the treated water storage tank 7 is a sealed pressurized ammonia water storage tank so that ammonia gas does not volatilize from the stored ammonia water.

[0033] The ammonia water temporarily stored in the treated water storage tank 7 is stored safely on board, or treated on board, or landed. When the concentration of ammonia water is high, the volume per ammonia component contained therein is small, so the volume of the treated water storage tank 7 can be reduced, and storage space can be saved. As an example of onboard treatment, the ammonia water can be used in a selective catalytic reduction (SCR) unit 17. When landed, it can be disposed of or used as a raw material for ammonium sulfate, a fertilizer, etc.

[0034] When ammonia water is used in the selective catalytic reduction unit 17, the ammonia water stored in the treated water storage tank 7 is supplied to the selective catalytic reduction unit 17 connected to the exhaust duct of the engine 3 by a transport pump 18a via a transport section 18. In the selective catalytic reduction unit 17, the ammonia component is converted into NOx in the engine exhaust gas. Ｘ The denitrification treatment is carried out by selective catalytic reduction (SCR). The denitrified exhaust gas is released into the atmosphere.

[0035] In the event of a power outage (power failure) due to a breakdown of the onboard generator or the like, pumps such as the feedwater pump 22a and the circulation pump 14 and instruments such as the concentration meters 12d and 13a become unusable, resulting in the problem of being unable to treat ammonia gas. Therefore, as a precaution against a power outage, it is preferable to provide an uninterruptible power supply (battery) (not shown). In the event of a power outage, the uninterruptible power supply supplies power to pumps such as the feedwater pump 22a and the circulation pump 14 and instruments such as the concentration meters 12d and 13a, enabling these pumps and instruments to operate. To drain water from the scrubber tank 13 to the treated water storage tank 7 in the event of a power outage, the uninterruptible power supply starts the circulation pump 14, closes the circulation on-off valve 13c, and opens the scrubber tank drain valve 13e.

[0036] Since the detoxification device 6 is divided into two stages, the water seal tank 12 and the scrubber tank 13, the amount of water supplied to and circulated by the water supply pump 22a and the circulation pump 14 is reduced in the event of a power outage compared to treating ammonia gas using only the water seal tank or only the scrubber tank, and the capacity of the uninterruptible power supply can be reduced.

[0037] In addition, a path is provided at the bottom of the scrubber tank 13, which bypasses the circulation pump 14, concentration meter 13a, and heat exchanger 13b and drains the ammonia water into the treated water storage tank 7 by gravity via an emergency drain valve 13f. When draining the ammonia water into the treated water storage tank 7 via the emergency drain valve 13f, it is advisable to provide the treated water storage tank 7 with a pressure relief valve (not shown) and connect the outlet of this pressure relief valve to the bottom of the water seal tank 12. This is to prevent the ammonia gas vented from the pressure relief valve from being released into the atmosphere.

[0038] [Operation Procedure] The ammonia water stored in the treated water storage tank 7 should have as high a concentration as possible in order to reduce the volume of the treated water storage tank 7 and save storage space. Therefore, the concentration of the ammonia water can be increased as follows.

[0039] (Starting up the device) The water seal tank water supply valve 12b and the scrubber tank water supply valve 13d are opened, and the water supply pump 22a is operated to supply water from the fresh water tank 22 to the water seal tank 12 and the scrubber tank 13, filling them with a certain amount of fresh water. The amount of water in the water seal tank 12 is detected by the level gauge 12a.

[0040] (Operation flow) When the engine 3 is started, stopped or emergency stopped, the purge gas supply valve 10, the on-off valve 5 and the on-off valve 2a are opened to discharge a mixed gas of ammonia gas and nitrogen gas from the fuel pipe 4 and the fuel supply device 2 and send it to the abatement device 6. The ammonia discharged from the fuel pipe 4 is depressurized in the gas-liquid separator 4a so that only the gas flows to the abatement device 6. The ammonia discharged from the fuel supply device 2 is depressurized before entering the gas-liquid separator in the fuel supply device 2, and by passing through the gas-liquid separator, only the gas flows to the abatement device 6.

[0041] The mixed gas of ammonia gas and nitrogen gas is introduced into the lower part of the water seal tank 12, and the ammonia gas dissolves in the fresh water in the water seal tank 12. The ammonia gas, volatilized ammonia gas, and nitrogen gas that do not dissolve in the fresh water in the water seal tank 12 are introduced from the upper part of the water seal tank 12 into the lower part of the scrubber tank 13.

[0042] In the scrubber tank 13, fresh water is sprayed from above to contact the ammonia gas, and the ammonia gas is dissolved in the fresh water. In the scrubber tank 13, the ammonia gas and the fresh water are brought into contact with each other in a counterflow manner, so that the ammonia gas is well dissolved in the fresh water.

[0043] The circulation on-off valve 13c is opened, the circulation pump 14 is operated, and the ammonia water is circulated from the bottom to the top of the scrubber tank 13, and the concentration of the ammonia water is detected by the concentration meter 13a.

[0044] When the ammonia water concentration reaches the desired concentration, the circulation on-off valve 13c is closed, and the scrubber tank drain valve 13e is opened to discharge the ammonia water into the treated water storage tank 7. The flow rate of the ammonia water discharged from the scrubber tank 13 is detected by a flow meter. Fresh water equivalent to the discharged amount is additionally supplied from the fresh water tank 22 to the scrubber tank 13 by opening the scrubber tank water supply valve 13d and operating the water supply pump 22a. The desired concentration of ammonia water is, for example, in the range of 5 to 15 wt %. This concentration is also suitable for use in the selective catalytic reduction (SCR) unit 17.

[0045] The purge gas supply valve 10 is opened, the supply of nitrogen gas to the fuel pipe 4 is continued, and the supply of the mixed gas of ammonia gas and nitrogen gas to the water tank 12 of the detoxification device 6 is continued until predetermined conditions for stopping the supply of the mixed gas to the detoxification device 6 are met.

[0046] The predetermined condition for stopping the supply of the mixed gas to the abatement device 6 is, for example, the lapse of a predetermined time, or the flow rate or pressure in the purge system (in the fuel supply device 2, in the fuel pipe 4, in the discharge line to the abatement device 6, and in the engine 3) reaching a threshold value. The flow rate or pressure in the purge system is detected by a float sensor or a pressure gauge.

[0047] The supply of the mixed gas to the decomposition device 6 is stopped by closing the purge gas supply valve 10, the on-off valve 5, and the on-off valve 2a to stop the supply of the mixed gas to the water seal tank 12, and by closing the circulation on-off valve 13c to stop the circulation of the ammonia water in the lower part of the scrubber tank 13 to the upper part of the scrubber tank 13.

[0048] After the supply of the mixed gas to the water seal tank 12 is stopped, the water seal tank drain valve 12c is opened and the drain pump 12e drains the ammonia water from the water seal tank 12 into the treated water storage tank 7. The concentration meter 12d confirms that the ammonia water drained from the water seal tank 12 has reached the desired concentration.

[0049] After the supply of the mixed gas to the water seal tank 12 is stopped, the scrubber tank drain valve 13e is opened and the ammonia water in the scrubber tank 13 is drained into the treated water storage tank 7 by the circulation pump 14. During the process of circulation from the bottom to the top of the scrubber tank 13, the ammonia water drained from the scrubber tank 13 is confirmed by the concentration meter 13a to have reached the desired concentration.

[0050] When the drainage of the ammonia water from the water seal tank 12 and the scrubber tank 13 is completed, the circulation pump 14 is stopped, and the water seal tank drain valve 12c and the scrubber tank drain valve 13e are closed.

[0051] Next, the water seal tank water supply valve 12b and the scrubber tank water supply valve 13d are opened, and the water supply pump 22a is operated to supply a predetermined amount of fresh water from the fresh water tank 22 to the water seal tank 12 and the scrubber tank 13, and the apparatus returns to its start-up state.

[0052] The ammonia water stored in the treated water storage tank 7 has reached the desired concentration, so it is suitable for use in denitrification treatment by being supplied to the selective reduction catalyst unit 17 via the transport section 18 by the transport pump 18a.

[0053] (When the water seal tank 12 is used for continuous treatment) The above-mentioned operation flow has been described as a so-called batch treatment in which, after pouring water into the water seal tank 12, the mixed gas is supplied without pouring or draining water, and then the supply of the mixed gas is stopped and the water is drained, but this is not limited to this, and continuous treatment may also be used. That is, the water seal tank 12 may be configured to detect the amount of drained liquid using the liquid level gauge 12a while draining ammonia water that has reached a desired concentration, and to supply clean water in an amount equivalent to the amount of drained liquid so that the liquid level position is maintained approximately constant. In this case, the dissolution of ammonia gas in the water seal tank 12 is a continuous treatment.

[0054] 2 is a block diagram showing the configuration of an ammonia gas treatment apparatus according to an improved embodiment (1) of the first embodiment of the present invention. Unlike the first embodiment, this improved embodiment is configured to return ammonia gas volatilized in the treated water storage tank 7 to the scrubber tank 13.

[0055] In this improved embodiment, the treated water storage tank 7 is a low-pressure tank, and ammonia gas is likely to volatilize from the ammonia water stored therein. The ammonia gas volatilized in the treated water storage tank 7 is returned to the abatement device 6, merges with the mixed gas from the upper part of the water seal tank 12, and is returned to the lower part of the scrubber tank 13.

[0056] A large amount of ammonia gas volatilizes from the ammonia water, but in this improved embodiment, the ammonia gas volatilizing in the treated water storage tank 7 is returned to the bottom of the scrubber tank 13, so that the ammonia gas can be safely treated while maintaining the concentration of the ammonia water in the scrubber tank 13.

[0057] In this improved embodiment, the drainage water from the water seal tank 12 can be sent to the treated water storage tank 7 by gravity, eliminating the need for a drainage pump 12e, making it possible to downsize the device and save power. Furthermore, in the event of a power outage, the emergency drainage valve 13f can be opened to drain water from the scrubber tank 13 into the treated water storage tank 7 by gravity, without passing through the circulation pump 14, concentration meter 13a, and heat exchanger 13b.

[0058] [Improvement (2) of the First Embodiment] Fig. 3 is a block diagram showing the configuration of an ammonia gas treatment apparatus according to an improvement (2) of the first embodiment of the present invention. This improvement differs from the first embodiment in that a pressurized buffer tank 16 is provided in the abatement device 6 as a precaution against power loss. Therefore, this improvement does not require the provision of an uninterruptible power supply.

[0059] In this improved embodiment, the fresh water introduced into the abatement device 6 is branched into three paths: one is supplied to the water seal tank 12 via the water seal tank water supply valve 12b, one is supplied to the upper part of the scrubber tank 13 via the scrubber tank water supply valve 13d, and the other is supplied to the pressurized buffer tank 16 via the inlet on-off valve 16a. The supply pipe to the upper part of the scrubber tank 13 joins with a return pipe that runs from the lower part of the scrubber tank 13 through a circulation on-off valve 13c.

[0060] The pressurized buffer tank 16 is a sealed pressurized tank, and nitrogen gas from the nitrogen gas supply device 11 passes through a pressurization valve 11a and is branched into two branches, and the nitrogen gas is supplied to pressurize the inside of the pressurized buffer tank 16. The pressurized buffer tank 16 can be operated in two ways: first, by filling it with fresh water and then pressurizing it with nitrogen gas, inert gas, or air; or by pressurizing the fresh water.

[0061] The pressurized buffer tank 16 has an inlet via an inlet on-off valve 16 a and an outlet via an outlet on-off valve 16 b. Water flowing out from the outlet of the pressurized buffer tank 16 passes through the outlet on-off valve 16 b and joins a supply pipe to the upper part of the scrubber tank 13 via a scrubber tank water supply valve 13 d.

[0062] In this improved ammonia gas treatment apparatus, at the start of treatment operation, the inlet valve 16a is opened in the pressurized buffer tank 16, a certain amount of fresh water is stored in the fresh water tank 22, and the inlet valve 16a is then closed. The pressurizing valve 11a is opened to apply a certain amount of pressure to the pressurized buffer tank 16 with nitrogen gas from the nitrogen gas supply device 11.

[0063] When the power supply is lost, the water supply pump 22a does not operate, so that water is supplied to the water seal tank 12 and the scrubber tank 13 by opening the water seal tank water supply valve 12b and the scrubber tank water supply valve 13d and opening the outlet opening / closing valve 16b, and a predetermined amount of fresh water is supplied from the pressurized buffer tank 16 using the pressure in the pressurized buffer tank 16. The pressurized buffer tank 16 maintains a pressure sufficient to spray fresh water in the scrubber tank 13. Furthermore, water can be discharged from the scrubber tank 13 by opening the emergency drain valve 13f and using the pressure in the pressurized buffer tank 16, even if the circulation pump 14 does not operate.

[0064] [Improvement (3) of the First Embodiment] Figure 4 is a block diagram showing the configuration of an ammonia gas treatment apparatus according to an improvement (3) of the first embodiment of the present invention. This improvement differs from the first embodiment in that ammonia gas volatilized in the treated water storage tank 7 is returned to the scrubber tank 13, and a pressurized buffer tank 16 is provided in the abatement device 6 as a precaution in the event of a power loss. Therefore, this improvement does not require the provision of an uninterruptible power supply.

[0065] In this improved embodiment, the treated water storage tank 7 is a low-pressure tank, and ammonia gas is likely to volatilize from the ammonia water stored therein. The ammonia gas volatilized in the treated water storage tank 7 is returned to the abatement device 6, merges with the mixed gas from the upper part of the water seal tank 12, and is returned to the lower part of the scrubber tank 13.

[0066] A large amount of ammonia gas volatilizes from the ammonia water, but in this improved embodiment, the ammonia gas volatilizing in the treated water storage tank 7 is returned to the bottom of the scrubber tank 13, so that the ammonia gas can be safely treated while maintaining the concentration of the ammonia water in the scrubber tank 13.

[0067] In this improved embodiment, the wastewater from the water seal tank 12 can be sent to the treated water storage tank 7 by gravity, so there is no need to install a drainage pump 12e, making it possible to reduce the size of the device configuration and save power.

[0068] In this improved embodiment, the response to power loss is the same as in the improved embodiment (2) of the first embodiment (FIG. 3).

[0069] [Second embodiment] Figure 5 is a block diagram showing the configuration of an ammonia gas treatment apparatus according to a second embodiment of the present invention. The same reference numerals as in Figures 1 to 4 designate the same components, and unless otherwise specified, the explanations in Figures 1 to 4 are used and will not be repeated here.

[0070] In this embodiment, as shown in FIG. 5, the ammonia water produced in the detoxification device 6 is supplied to a neutralization treatment device 23 rather than to a treated water storage tank.

[0071] In this embodiment, the liquid may be sent from the water seal tank 12 to the neutralization treatment device 23 by overflow, gravity, or by using a drain pump 12e.

[0072] In the neutralization treatment device 23, the ammonia water is neutralized by an acid neutralizer supplied from the acid neutralizer tank 8. Neutralization (pH 8 or less) can be confirmed by a pH meter or ion meter provided in the neutralization treatment device 23. The neutralized water obtained by neutralizing the ammonia water with the acid neutralizer is sent to and stored in the neutralized water storage tank 15. The liquid may be sent from the neutralization treatment device 23 to the neutralized water storage tank 15 by overflow, gravity, or pump.

[0073] The preferred concentration of the ammonia water sent to the neutralization treatment device 23 may be any concentration that allows neutralization by the acidic neutralizing agent. Since ammonia gas does not volatilize from the neutralization water stored in the neutralization water storage tank 15, it is not necessarily necessary to provide a line for returning the ammonia gas to the scrubber tank 13.

[0074] In this embodiment, too, as in the improved forms (2) and (3) of the first embodiment, the abatement device 6 may be provided with a pressurized buffer tank 16 as a precaution in the event of a power outage.

[0075] In this embodiment, the acid neutralizer stored in the acid neutralizer tank 8 may be any acidic substance capable of neutralizing ammonia water. For example, carbon dioxide or an organic acid such as citric acid is preferred, or any other acidic substance may be used. The acid neutralizer may be in the form of a solid, such as dry ice or an organic acid crystal such as citric acid; a liquid, such as liquefied carbon dioxide, dilute sulfuric acid, dilute nitric acid, or aqua regia; or a gas, such as carbon dioxide gas. When a liquid or gaseous acid neutralizer is used, a sealed, pressurized storage tank, such as a full-refrigerated (atmospheric pressure) or semi-refrigerated (semi-pressurized) type, is used as the acid neutralizer tank 8. Carbon dioxide or an organic acid such as citric acid is preferred because it is easy to handle and safe, and does not produce precipitates when neutralized water is used in the selective reduction catalyst unit 17.

[0076] When a liquid acid neutralizer is used, a suction pump is provided in the acid neutralizer tank 8 as shown in Fig. 5, and this suction pump sends the stored acid neutralizer to a pipe leading to the neutralization treatment device 23. A flow meter (not shown) is provided in the pipe leading to the neutralization treatment device 23, and the amount of acid neutralizer supplied to the neutralization treatment device 23 is controlled by adjusting the flow control valve 9 in accordance with the measurement result of this flow meter. The suction pump for the acid neutralizer may also be used as the pump that sends out ammonia water from the detoxification device 6.

[0077] When a gaseous acid neutralizer is used, it is sent out from the acid neutralizer tank 8 by a gas blower or other gas blower (not shown). The amount of acid neutralizer supplied to the neutralization treatment device 23 is controlled by adjusting the flow control valve 9 in accordance with the measurement results of a flow meter provided in the piping to the neutralization treatment device 23.

[0078] When a solid acid neutralizer is used, it is sent out from the acid neutralizer tank 8 by a transfer device such as a screw conveyor (not shown). In this case, the flow control valve 9 is not provided, and the amount of acid neutralizer supplied to the neutralization treatment device 23 is controlled by adjusting the transfer speed of the transfer device in accordance with the weighing result of a weighing scale provided in the transfer path.

[0079] In the neutralization treatment device 23, if a liquid or solid acid neutralizer that is gaseous at room temperature is added to the ammonia water, the heat of vaporization of the acid neutralizer is absorbed, thereby suppressing the heat of the neutralization reaction with ammonia.

[0080] Instead of the acid neutralizer tank 8, a neutralizing liquid tank (not shown) may be provided in which an aqueous solution of an acid neutralizer dissolved in clean water is stored as a neutralizing liquid. The neutralizing liquid is pumped from the neutralizing liquid tank by a liquid pump. In this case, too, the supply amount of the neutralizing liquid is controlled by adjusting the flow control valve 9 in accordance with the measurement results of a flow meter installed in the piping to the neutralization treatment device 23.

[0081] The neutralized water stored in the neutralized water storage tank 15 can be discharged overboard in sea areas where there are no discharge regulations. Alternatively, the neutralized water may be sent to the selective catalytic reduction unit 17 to generate ammonia gas, which can then be used as a reducing agent. Carbon dioxide and organic acids such as citric acid are preferred as neutralizing agents because they do not produce precipitates when used in the selective catalytic reduction unit 17.

[0082] The neutralization water storage tank 15 may be provided with a return pipe that sends out a portion of the neutralization water stored in the neutralization water storage tank 15 from the neutralization water storage tank 15 using a circulation pump and returns this neutralization water to the neutralization treatment device 23. If neutralization is not sufficient and neutralization water containing an ammonia component is sent to the neutralization water storage tank 15 through this return pipe, this neutralization water can be returned to the neutralization treatment device 23 for further neutralization. Furthermore, if the pH value of the neutralization water sent to the neutralization water storage tank 15 has become lower than 7 (acidic), this neutralization water can be returned to the neutralization treatment device 23 and mixed with a liquid with a high pH value (basic) before neutralization for neutralization.

[0083] When the neutralized water stored in the neutralized water storage tank 15 is sent to the selective catalytic reduction unit 17, it is sent via a transport section 18 to the selective catalytic reduction unit 17 connected to the exhaust duct of the engine 3 by a transport pump 18a. In the selective catalytic reduction unit 17, ammonia gas generated from the neutralized water is converted into NO in the engine exhaust gas. Ｘ The denitrified exhaust gas is discharged into the atmosphere. When denitrification is performed in the selective catalytic reduction unit 17 using neutralized water, it is preferable that the neutralized water has a salt concentration equal to or higher than a desired concentration in order to generate a sufficient amount of ammonia gas.

[0084] In this way, the volume of the neutralization water can be reduced by generating ammonia gas from the neutralization water and using it in the selective catalytic reduction unit 17. In addition, there is no need to land the neutralization water, and there is no need to discharge it into the sea.

[0085] As described above in each embodiment, the present invention provides an ammonia gas treatment device and treatment method that can safely treat the ammonia gas generated on a ship carrying liquefied ammonia as cargo or engine fuel, adjust the ammonia gas to a desired concentration, and reduce the size of the storage tank and the storage space.

[0086] LIST OF SYMBOLS 1 Liquefied ammonia tank 1a Suction pump 2 Fuel supply device 2a On-off valve 3 Engine 4 Fuel piping 4a Gas-liquid separator 5 On-off valve 6 Detoxification device 7 Treated water storage tank 8 Acid neutralizer tank 9 Flow control valve 10 Purge gas supply valve 11 Nitrogen gas supply device 11a Pressurization valve 12 Water seal tank 12a Liquid level gauge 12b Water seal tank water supply valve 12c Water seal tank drain valve 12d Concentration meter 12e Drain pump 13 Scrubber tank 13a Concentration meter 13b Heat exchanger 13c Circulation on-off valve 13d Scrubber tank water supply valve 13e Scrubber tank drain valve 13f Emergency drain valve 14 Circulation pump 15 Neutralized water storage tank 16 Pressurized buffer tank 16a Inlet on-off valve 16b Outlet on-off valve 17 Selective reduction catalyst unit 18 Transport section 22 Fresh water tank 23 Neutralization treatment device

Claims

1. An ammonia gas treatment device for a ship carrying liquefied ammonia as cargo or engine fuel, comprising a detoxification device for dissolving in fresh water ammonia gas and / or ammonia gas vaporized from liquefied ammonia that has evaporated from the cargo or remained in the engine fuel supply line, into fresh water to produce ammonia water, the detoxification device comprising: a water seal tank in which fresh water is stored, into which the ammonia gas vaporized from the liquefied ammonia and / or the ammonia gas is introduced from a lower part, and the ammonia gas is dissolved in the stored fresh water to produce ammonia water; and a scrubber into which ammonia gas discharged from an upper part of the water seal tank is introduced at the lower part and into which fresh water is supplied, and into which the ammonia gas is dissolved in the fresh water to produce ammonia water.

2. The ammonia gas treatment device according to claim 1, characterized in that the ammonia removal device has a circulation pump that sends the ammonia water in the scrubber to an upper portion of the scrubber.

3. The ammonia gas treatment device according to claim 2, characterized in that the ammonia removal device has a concentration meter through which the ammonia water sent to the upper part of the scrubber passes.

4. The ammonia gas treatment device according to claim 3, characterized in that the ammonia removal device has a circulation on-off valve through which ammonia water sent to the upper part of the scrubber passes, and a scrubber drain valve through which ammonia water sent from the scrubber to a treated water storage tank passes, and the ammonia water in the scrubber is sent to the upper part of the scrubber until the concentration of the ammonia water detected by the concentration meter reaches a desired concentration.

5. The ammonia gas treatment device according to claim 2, further comprising an uninterruptible power supply for driving the circulation pump, wherein in the event of a loss of power supply for driving the circulation pump, the circulation pump can be driven by the uninterruptible power supply.

6. The ammonia gas treatment device according to claim 2, characterized in that the ammonia removal device has a heat exchanger for cooling the ammonia water sent to the upper part of the scrubber by the circulation pump.

7. An ammonia gas treatment device as described in any one of claims 1 to 6, characterized in that it comprises a treated water storage tank for storing the ammonia water produced in the ammonia removal device, and ammonia gas vaporized from the treated water storage tank is introduced into the lower part of the scrubber.

8. An ammonia gas treatment device as described in any one of claims 1 to 6, characterized in that it further comprises a treated water storage tank to which the ammonia water produced in the detoxification device is sent and which stores the ammonia water, the treated water storage tank being a pressurized ammonia water storage tank.

9. An ammonia gas treatment device according to any one of claims 1 to 6, characterized in that it comprises a selective reduction catalyst unit into which exhaust gas from an engine of the ship is introduced, the selective reduction catalyst unit being supplied with ammonia water produced in the abatement device and performing denitrification treatment of the exhaust gas.

10. An ammonia gas treatment device as described in any one of claims 1 to 5, further comprising a neutralization treatment device to which ammonia water is sent from the detoxification device, the neutralization treatment device neutralizing the ammonia water with an acidic neutralizing agent to produce neutralized water.

11. The ammonia gas treatment device according to claim 10, further comprising a selective reduction catalyst unit into which exhaust gas from the ship's engine is introduced, the selective reduction catalyst unit being supplied with neutralized water produced in the neutralization treatment device and performing denitrification treatment of the exhaust gas.

12. An ammonia gas treatment device as described in any one of claims 2 to 4, characterized in that the fresh water is sent from a fresh water tank that stores the fresh water to a pressurized buffer tank and stored therein, and in the event of a loss of power to drive the circulating pump, the fresh water is supplied to the top of the scrubber by the pressure in the pressurized buffer tank.

13. The ammonia gas treatment device according to claim 12, characterized in that the pressurized buffer tank is pressurized by a pressure source of ammonia gas produced by vaporization of liquefied ammonia remaining in the fuel supply line and / or an inert gas which purges the ammonia gas and sends it to the ammonia removal device.

14. An ammonia gas treatment device as described in claim 2, characterized in that it has a heat exchanger that cools the ammonia water sent to the top of the scrubber by the circulation pump, and is equipped with a neutralization treatment device to which ammonia water is sent from the decontamination device, the neutralization treatment device neutralizes the ammonia water with an acidic neutralizing agent to produce neutralized water, and is equipped with a selective reduction catalyst unit to which exhaust gas from the ship's engine is introduced, and the selective reduction catalyst unit is supplied with the neutralized water produced in the neutralization treatment device and performs denitrification treatment of the exhaust gas.

15. The ammonia gas treatment device according to claim 14, further comprising an uninterruptible power supply for driving the circulation pump, wherein in the event of a loss of power supply for driving the circulation pump, the circulation pump can be driven by the uninterruptible power supply.

16. An ammonia gas treatment device as described in claim 2, characterized in that it has a heat exchanger that cools the ammonia water sent to the top of the scrubber by the circulation pump, the fresh water is sent from a fresh water tank that stores the fresh water to a pressurized buffer tank and stored therein, and in the event of a loss of power to drive the circulation pump, the fresh water is supplied to the top of the scrubber by the pressure in the pressurized buffer tank, and the pressurized buffer tank is pressurized by a pressure source of ammonia gas vaporized from liquefied ammonia remaining in the fuel supply line and / or an inert gas that purges the ammonia gas and sends it to the abatement device.

17. An ammonia gas treatment device as described in claim 14, 15 or 16, characterized in that it comprises a treated water storage tank for storing the ammonia water produced in the ammonia removal device, and ammonia gas vaporized from the treated water storage tank is introduced into the lower part of the scrubber.

18. An ammonia gas treatment device as described in claim 14, 15 or 16, characterized in that it comprises a treated water storage tank for storing the ammonia water produced in the detoxification device, and the treated water storage tank is a pressurized ammonia water storage tank.

19. An ammonia gas treatment device as claimed in claim 14, 15 or 16, characterized in that it comprises a selective reduction catalyst unit into which exhaust gas from the ship's engine is introduced, said selective reduction catalyst unit being supplied with ammonia water produced in the abatement device and performing denitrification treatment of the exhaust gas.

20. An ammonia gas treatment device as claimed in claim 16, further comprising a neutralization treatment device to which ammonia water is sent from the detoxification device, the neutralization treatment device neutralizing the ammonia water with an acidic neutralizing agent to produce neutralized water.

21. The ammonia gas treatment device according to claim 20, further comprising a selective reduction catalyst unit into which exhaust gas from the ship's engine is introduced, the selective reduction catalyst unit being supplied with neutralized water produced in the neutralization treatment device and performing denitrification treatment of the exhaust gas.

22. A method for treating ammonia gas in a ship carrying liquefied ammonia as cargo or engine fuel, comprising: sending ammonia gas and / or ammonia gas formed by vaporizing liquefied ammonia that has evaporated from the cargo or remained in the engine fuel supply line to an abatement device, the abatement device comprising: a water seal tank in which fresh water is stored, the ammonia gas formed by vaporizing the liquefied ammonia and / or the ammonia gas is introduced from a lower part of the water seal tank and the ammonia gas is dissolved in the stored fresh water to obtain ammonia water; and a scrubber into which ammonia gas discharged from an upper part of the water seal tank is introduced to a lower part and fresh water is supplied to an upper part of the water seal tank and the ammonia gas is dissolved in the fresh water to obtain ammonia water, and comprising a step of dissolving the ammonia gas formed by vaporizing the liquefied ammonia and / or the ammonia gas in the abatement device.

23. The method for treating ammonia gas according to claim 22, characterized in that the ammonia removal device is provided with a circulation pump, and the ammonia water in the scrubber is sent to an upper portion of the scrubber by the circulation pump.

24. The method for treating ammonia gas according to claim 23, characterized in that a concentration meter is provided in the ammonia removal device, and the concentration meter measures the ammonia water sent by the circulation pump to the upper part of the scrubber.

25. The method for treating ammonia gas according to claim 24, characterized in that the ammonia water in the scrubber is sent to the upper part of the scrubber until the concentration of the ammonia water detected by the concentration meter reaches a desired concentration.

26. The method for treating ammonia gas as described in claim 23, further comprising providing an uninterruptible power supply for driving the circulation pump, and in the event of a loss of power supply for driving the circulation pump, the circulation pump can be driven by the uninterruptible power supply.

27. The method for treating ammonia gas according to claim 23, characterized in that a heat exchanger is provided in the abatement device, and the ammonia water sent by the circulation pump to the upper part of the scrubber is cooled by the heat exchanger.

28. A method for treating ammonia gas as described in any one of claims 22 to 27, characterized in that a treated water storage tank is provided, ammonia water produced by the decontamination device is sent to and stored in the treated water storage tank, and ammonia gas vaporized from the treated water storage tank is introduced into the lower part of the scrubber.

29. A method for treating ammonia gas as described in any one of claims 22 to 27, characterized in that a treated water storage tank which is a pressurized ammonia water storage tank is provided, and the ammonia water generated by the ammonia removal device is sent to and stored in the treated water storage tank.

30. A method for treating ammonia gas as described in any one of claims 22 to 27, characterized in that a selective reduction catalyst unit is provided, and exhaust gas from the engine of the ship and ammonia water generated by the ammonia removal device are supplied to the selective reduction catalyst unit, thereby performing denitrification treatment of the exhaust gas.

31. A method for treating ammonia gas as described in any one of claims 22 to 26, characterized in that a neutralization treatment device is provided, the ammonia water generated by the detoxification device and an acidic neutralizing agent are supplied to the neutralization treatment device, and the ammonia water is neutralized to produce neutralized water.

32. The method for treating ammonia gas according to claim 31, further comprising the steps of: providing a selective catalytic reduction unit; supplying exhaust gas from the engine of the ship and neutralized water produced by the neutralization treatment device to the selective catalytic reduction unit; and performing denitrification treatment of the exhaust gas.

33. A method for treating ammonia gas as described in any one of claims 23 to 25, characterized in that a pressurized buffer tank is provided, the fresh water is sent to and stored in the pressurized buffer tank, and in the event of a loss of power supply to drive the circulating pump, the fresh water is supplied to the top of the scrubber by the pressure within the pressurized buffer tank.

34. The method for treating ammonia gas according to claim 33, characterized in that the inside of the pressurized buffer tank is pressurized by a pressure source of ammonia gas produced by vaporization of liquefied ammonia remaining in the fuel supply line and / or an inert gas which purges the ammonia gas and sends it to the abatement device.

35. The method for treating ammonia gas as described in claim 23, characterized in that the decontamination device has a heat exchanger for cooling the ammonia water sent to the upper part of the scrubber by the circulation pump, is provided with a neutralization treatment device, the ammonia water produced by the decontamination device and an acidic neutralizing agent are supplied to the neutralization treatment device to neutralize the ammonia water to produce neutralized water, and a selective reduction catalyst unit is provided, and the selective reduction catalyst unit is supplied with exhaust gas from the ship's engine and the neutralized water produced by the neutralization treatment device to perform denitrification treatment of the exhaust gas.

36. The method for treating ammonia gas as described in claim 35, further comprising providing an uninterruptible power supply for driving the circulation pump, and in the event of a loss of power supply for driving the circulation pump, the circulation pump can be driven by the uninterruptible power supply.

37. The method for treating ammonia gas as described in claim 23, characterized in that the ammonia decontamination device has a heat exchanger for cooling the ammonia water sent to the upper part of the scrubber by the circulation pump, and is provided with a pressurized buffer tank, the fresh water is sent to the pressurized buffer tank for storage, and in the event of a loss of power to drive the circulation pump, the fresh water is supplied to the upper part of the scrubber by the pressure in the pressurized buffer tank, and the inside of the pressurized buffer tank is pressurized by a pressure source of ammonia gas vaporized from liquefied ammonia remaining in the fuel supply line and / or an inert gas which purges the ammonia gas and sends it to the ammonia decontamination device.

38. A method for treating ammonia gas as described in claim 35, 36 or 37, characterized in that a treated water storage tank is provided, ammonia water generated by the decontamination device is sent to and stored in the treated water storage tank, and ammonia gas vaporized from the treated water storage tank is introduced into the lower part of the scrubber.

39. A method for treating ammonia gas as claimed in claim 35, 36 or 37, characterized in that a treated water storage tank which is a pressurized ammonia water storage tank is provided, and the ammonia water generated by the ammonia removal device is sent to and stored in the treated water storage tank.

40. A method for treating ammonia gas as claimed in claim 35, 36 or 37, characterized in that a selective reduction catalyst unit is provided, and exhaust gas from the engine of the ship and ammonia water produced by the ammonia removal device are supplied to the selective reduction catalyst unit to perform denitrification treatment of the exhaust gas.

41. A method for treating ammonia gas as described in claim 37, further comprising the steps of: providing a neutralization treatment device, supplying the ammonia water produced by the detoxification device and an acidic neutralizing agent to the neutralization treatment device, and neutralizing the ammonia water to produce neutralized water.

42. A method for treating ammonia gas as described in claim 41, further comprising the steps of: providing a selective reduction catalyst unit; supplying exhaust gas from the engine of the ship and neutralized water produced by the neutralization treatment device to the selective reduction catalyst unit; and performing denitrification treatment of the exhaust gas.

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