Apparatus and method for treating ammonia gas

Abstract

To provide 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 a storage space.SOLUTION: In a ship carrying liquefied ammonia as cargo or fuel, a detoxification device 6 for obtaining ammonia gas volatilized from the cargo or generated by gasification of liquefied ammonia remaining in a fuel supply line 2, 4 and / or for dissolving the ammonia gas in clean water comprises: a water sealing tank 12 in which the ammonia gas is dissolved in stored clean water; a scrubber tank 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; a circulation pump 14 that transfers the ammonia water present in the scrubber tank 13 to an upper part of the scrubber tank 13; and a heat exchanger 13b that cools the ammonia water transferred to the upper part of the scrubber tank 13.SELECTED DRAWING: Figure 1

Description

[Technical field]

[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 capable of safely storing ammonia gas formed by vaporizing liquefied ammonia that has evaporated from the cargo or remained in the engine fuel supply line and / or ammonia water formed by dissolving ammonia gas in fresh water, and capable of reducing storage space. [Background technology]

[0002] In light of 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 fuel within the flammable range in the event of an abnormality. In addition, in tanks that store ammonia, ammonia gas called 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, so it must be disposed of by releasing it into the atmosphere, etc.

[0003] However, since ammonia gas is flammable and toxic, it will affect the human body if it is released directly into the atmosphere. Therefore, it is necessary to remove ammonia gas from the 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6934555 Summary of the Invention [Problem to be solved by the invention]

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

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

[0008] The above problems are solved by the following inventions. 1. An apparatus for treating ammonia gas in a ship carrying liquefied ammonia as cargo or ship engine fuel, comprising: A detoxification device is provided for dissolving ammonia gas and / or ammonia water in fresh water, the ammonia gas being vaporized from the liquefied ammonia volatilized from the cargo or remaining in the fuel supply line of the engine, The abatement device comprises: a water tank in which fresh water is stored, and ammonia gas obtained by vaporizing the liquefied ammonia and / or the ammonia gas is introduced from a lower portion thereof, and the ammonia gas is dissolved in the stored fresh water to produce ammonia water; a scrubber tank in which ammonia gas discharged from an upper portion of the water tank is introduced into a lower portion and fresh water is supplied to an upper portion of the water tank, and the ammonia gas is dissolved in the fresh water to produce ammonia water; A circulation pump that sends the ammonia water in the scrubber tank to an upper portion of the scrubber tank; a heat exchanger for cooling the ammonia water sent to the upper part of the scrubber tank by the circulation pump; have 2. An ammonia gas treatment device comprising: 2. A treated water storage tank is provided to store the ammonia water generated by the decontamination device, Ammonia gas volatilized from the treated water storage tank is introduced into the lower part of the scrubber tank. 2. The ammonia gas treatment device according to claim 1. 3. A treated water storage tank is provided to store the ammonia water generated by the decontamination device, The treated water storage tank is a pressurized ammonia water storage tank. 2. The ammonia gas treatment device according to claim 1. 4. a selective catalytic reduction unit into which exhaust gas from an engine of the ship is introduced, The selective catalytic reduction unit is supplied with the ammonia water produced in the detoxification device and performs denitrification of the exhaust gas. 2. The ammonia gas treatment device according to claim 1. 5. a neutralization treatment device to which ammonia water is sent from the detoxification device, The neutralization treatment device neutralizes the ammonia water with an acidic neutralizing agent to produce neutralized water. 2. The ammonia gas treatment device according to claim 1. 6. a selective catalytic reduction unit into which exhaust gas from an engine of the ship is introduced, The selective catalytic reduction unit is supplied with neutralized water produced by the neutralization treatment device and performs denitrification treatment of the exhaust gas. 6. The ammonia gas treatment device according to item 5 above. 7. 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 supply for driving the circulating pump, the fresh water is supplied to the upper part of the scrubber tank by the pressure in the pressurized buffer tank. 7. The ammonia gas treatment device according to any one of 1 to 6 above. 8. The pressurized buffer tank is pressurized by a pressure source of ammonia gas produced by vaporizing 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. 8. The ammonia gas treatment device according to claim 7. 9. An uninterruptible power supply that drives the circulating pump, When a power source for driving the circulating pump is lost, the circulating pump can be driven by the uninterruptible power source. 7. The ammonia gas treatment device according to any one of 1 to 6 above. 10. A method for treating ammonia gas in a ship carrying liquefied ammonia as cargo or ship engine fuel, comprising the steps of: Sending ammonia gas and / or ammonia gas vaporized from liquefied ammonia volatilized from the cargo or remaining in the fuel supply line of the engine to a detoxification device; The abatement device comprises: a water tank in which fresh water is stored, and ammonia gas obtained by vaporizing the liquefied ammonia and / or the ammonia gas is introduced from a lower portion thereof, and the ammonia gas is dissolved in the stored fresh water to produce ammonia water; a scrubber tank in which ammonia gas discharged from an upper portion of the water tank is introduced into a lower portion and fresh water is supplied to an upper portion of the water tank, and the ammonia gas is dissolved in the fresh water to produce ammonia water; A circulation pump that sends the ammonia water in the scrubber tank to an upper portion of the scrubber tank; a heat exchanger for cooling the ammonia water sent to the upper part of the scrubber tank by the circulation pump; having In the detoxification device, the liquefied ammonia is evaporated into ammonia gas and / or the ammonia gas is dissolved in fresh water. 1. A method for treating ammonia gas comprising the steps of: 11. A treated water storage tank is provided. The ammonia water generated by the detoxification device is sent to the treated water storage tank and stored therein; The ammonia gas volatilized from the treated water storage tank is introduced into the lower part of the scrubber tank. 11. The method for treating ammonia gas according to claim 10. 12. A pressurized ammonia water storage tank is provided to store treated water. The ammonia water generated by the detoxification device is sent to the treated water storage tank and stored therein. 11. The method for treating ammonia gas according to claim 10. 13. A selective catalytic reduction unit is provided. The selective catalytic reduction unit is supplied with exhaust gas from the engine of the ship and ammonia water produced by the ammonia removal device, and performs denitrification of the exhaust gas. 11. The method for treating ammonia gas according to claim 10. 14. A neutralization treatment device is provided, The ammonia water generated by the detoxification device and an acid neutralizer are supplied to the neutralization treatment device, and the ammonia water is neutralized to produce neutralized water. 11. The method for treating ammonia gas according to claim 10. 15. A selective catalytic reduction unit is provided. The selective catalytic reduction unit is supplied with exhaust gas from the engine of the ship and neutralized water produced by the neutralization treatment device, and performs denitrification treatment of the exhaust gas. 15. The method for treating ammonia gas according to claim 14, 16. 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 upper portion of the scrubber tank by the pressure in the pressurized buffer tank. 16. The method for treating ammonia gas according to any one of 10 to 15 above, 17. 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 that purges the ammonia gas and sends it to the abatement device. 17. The method for treating ammonia gas according to claim 16, 18. providing an uninterruptible power supply for driving the circulating pump; When a power source for driving the circulating pump is lost, the circulating pump can be driven by the uninterruptible power source. 16. The method for treating ammonia gas according to any one of 10 to 15 above, Effect of the Invention

[0009] According to the present invention, it is possible to provide an ammonia gas treatment device and a 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. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing the configuration of an ammonia gas treatment device according to a first embodiment of the present invention. [Diagram 2] FIG. 1 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. [Diagram 3] FIG. 1 is a block diagram showing the configuration of an ammonia gas treatment device according to an improved embodiment (2) of the first embodiment of the present invention. [Figure 4] FIG. 1 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. [Diagram 5] FIG. 2 is a block diagram showing the configuration of an ammonia gas treatment device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0012] The present invention makes it possible to safely store 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 makes it possible to reduce the storage space.

[0013] [First embodiment] [Device configuration] Fig. 1 is a block diagram showing the configuration of an ammonia gas treatment apparatus according to a first embodiment of the present invention. The ammonia gas treatment method according to the first embodiment of the present invention is carried out by this ammonia gas treatment apparatus. In Fig. 1, the liquid flow path is shown by a solid line, and the gas flow path is shown by a dotted line. This is the same in other drawings described later.

[0014] As shown in FIG. 1, the ammonia gas treatment device of this embodiment treats ammonia gas vaporized from 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 a ship's engine, or ammonia gas (boil-off gas) introduced from a cargo ammonia tank (not shown).

[0015] The fuel supply line is composed of a fuel supply device 2 and a fuel pipe 4, and is a path for supplying liquefied ammonia fuel to the engine 3 via the fuel pipe 4 by a compressor, a pump, a heat exchanger, etc., of the fuel supply device 2. Note that the fuel supply device 2 does not have to be provided if it is unnecessary. Also, the fuel pipe 4 may be composed of a supply pipe for supplying ammonia gas from the fuel supply device 2 to the engine 3, and a return pipe for returning excess ammonia gas from the engine 3 to the fuel supply device 2. Although not shown, an opening / closing valve capable of closing 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 on the liquefied ammonia tank 1 side of the fuel supply device 2 and the engine 3 side of the fuel piping 4.

[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 liquid state of the liquefied ammonia, the inside of liquefied ammonia tank 1 is kept 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 fully refrigerated (atmospheric pressure) or semi-refrigerated (semi-pressurized) tank, which is thin and easy to process, is mainly used as the liquefied ammonia tank 1. Inside liquefied ammonia tank 1, there is a suction pump 1a, which sends the stored liquefied ammonia out to a pipe to fuel supply device 2.

[0017] Cargo ammonia tanks store liquefied ammonia as cargo, rather than as fuel to be used for engines 3 etc. As with liquefied ammonia tank 1, the interior of the cargo ammonia tank is kept at high pressure or low temperature in order to maintain the liquid state of the liquefied ammonia inside the cargo ammonia tank. When a large amount of liquefied ammonia is loaded onto a ship, the cargo ammonia tanks that are mainly used are full-refrigerated (atmospheric pressure) or semi-refrigerated (semi-pressurized) types, which are thin and 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, and heats up the inside of the combustion chamber, thereby allowing the ammonia fuel to burn well. When the inside of the combustion chamber is heated to a state where only the ammonia fuel can be burned, the supply of the pilot fuel may be stopped. If the engine 3 is capable of burning only the 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. In the dual-fuel engine, it is possible to selectively switch between a mode in which the engine is operated mainly using liquefied ammonia fuel and a fossil fuel such as heavy oil as an ignition source, and a fossil fuel mode in which the engine is operated only using 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 stopped in an emergency.

[0020] When the engine 3 is started, stopped, or stopped in an emergency, the remaining liquefied ammonia is vaporized into ammonia gas and / or ammonia gas, which is introduced from the fuel pipe 4 through the gas-liquid separator 4a and the on-off valve 5 into the abatement device 6. Also, from the fuel supply device 2, ammonia gas and / or ammonia gas vaporized from remaining liquefied ammonia is introduced into the detoxification device 6 via the on-off valve 2a when starting, stopping or emergency stopping the engine 3, and during maintenance, etc. Note that in the fuel supply device 2, a gas-liquid separator is provided at an outlet for the ammonia gas and / or ammonia gas vaporized from remaining liquefied ammonia, together with a pump, etc. 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 mixed gas. When ammonia gas is introduced into the abatement 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 the cargo ammonia tank.

[0021] The detoxification device 6 is configured to include a water tank 12, a scrubber tank 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 tank 12.

[0022] Fresh water is stored in the water seal tank 12, and a mixed gas of ammonia gas and nitrogen is introduced from the bottom. Here, the fresh water is water that contains as few impurities and additives as possible, such as distilled water, ion-exchanged water, filtered water, etc. 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 the bottom surface of the water seal tank 12 in consideration of increasing 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 liquid level gauge 12a. Ammonia gas that has not dissolved in the fresh water, ammonia gas that has volatilized from the ammonia water, and a mixed gas of nitrogen are discharged from the top of the water seal tank 12. The top of the water seal tank 12 may be any point above the water level of the ammonia water in the water seal tank 12.

[0024] Nitrogen gas can also be supplied from a nitrogen gas supply device 11 through a pressure valve 11a to the bottom of the water seal tank 12. In the water seal tank 12, a certain amount of nitrogen gas is bubbled, thereby preventing freezing in winter and providing a dilution effect. In order to prevent freezing, other inert gases or air may be used instead of nitrogen gas. The dilution effect is the effect of reducing 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 tank 12 to a desired concentration (for example, 25 mg / Nm 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 mixed gas discharged from the top of the water tank 12 is introduced into the lower part of the scrubber tank 13. In the scrubber tank 13, fresh water is sprayed downward from the top, and the ammonia component of the mixed gas is dissolved in the sprayed fresh water to produce ammonia water. In consideration of extending the contact time between the fresh water and the ammonia gas in the scrubber tank 13, the lower part of the scrubber tank 13 is preferably the bottom surface of the scrubber tank 13, and the upper part of the scrubber tank 13 is preferably the top surface of the scrubber tank 13.

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

[0027] The circulation pump 14 returns the ammonia water in 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 that is returned to the upper part of the scrubber tank 13 by the circulation pump 14. The refrigerant that can be used is one that has been cooled with fresh water or seawater. The ammonia water returned to the top of the scrubber tank 13 is sprayed downward again. When ammonia gas is supplied to the scrubber tank 13, this ammonia water is cooled by the heat exchanger 13b, thereby suppressing the influence of reaction heat. In addition, the amount of dissolved ammonia components can be increased by lowering the temperature of the ammonia water. This makes it possible to reduce the volume per unit of ammonia component contained, and therefore the storage space required. The concentration meter 13a may be replaced with a pH meter, a density meter, a conductivity meter, etc. A flow meter (not shown) may be provided on the path of the ammonia water returned to the upper part of the scrubber tank 13.

[0028] In this abatement device 6, the ammonia gas volatilized from the water tank 12 is recovered by the scrubber tank 13, so that 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 can be problematic. However, the ammonia gas can be safely treated by a detoxification device 6 having a water-sealed tank 12, a scrubber tank 13, and a circulation pump 14.

[0029] The fresh water supplied to the water tank 12 and the scrubber tank 13 in the abatement system 6 may be generated by, for example, a water maker on board the ship and stored in the fresh water tank 22, or the fresh water may be stored in a tank in advance. The stored fresh water is introduced from the fresh water tank 22 to 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 is supplied 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 merges with a return pipe that runs from the lower part of the scrubber tank 13 through a circulation on-off valve 13c.

[0031] The drainage (ammonia water) from the bottom of the water seal tank 12 is sent by the drain pump 12e through the water seal tank drain valve 12c and the 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. The wastewater from the bottom of the scrubber tank 13 is sent by the circulation pump 14 through a concentration meter 13a and a heat exchanger 13b, and then through the 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 is prevented from volatilizing from the stored ammonia water.

[0033] The ammonia water temporarily stored in the treated water storage tank 7 is safely stored on board the ship, or is treated on board, or is unloaded on shore. When the concentration of ammonia water is high, the volume per unit of ammonia component contained therein is small, so the volume of the treated water storage tank 7 can be reduced, and the storage space can be reduced. On-board treatment may include use in a selective catalytic reduction (SCR) unit 17 . If the material is brought ashore, it can be disposed of or used as a raw material for ammonium sulfate fertilizer.

[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 NO in the engine exhaust gas. X This reacts with the nitrogen oxides to perform the selective catalytic reduction (SCR) method of denitrification. The denitrified exhaust gas is then released into the atmosphere.

[0035] Furthermore, in the event of a loss of power (blackout) due to a breakdown in the onboard generator or other reasons, 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 that ammonia gas cannot be treated. Therefore, it is preferable to provide an uninterruptible power supply (battery) (not shown) in case of power loss. The uninterruptible power supply supplies power to pumps such as the water supply pump 22a and the circulation pump 14 and meters such as the concentration meters 12d and 13a in the event of power loss, enabling these pumps and meters to operate. To drain water from the scrubber tank 13 to the treated water storage tank 7 when power is lost, the circulation pump 14 is started by the uninterruptible power supply, the circulation on-off valve 13c is closed, and the scrubber tank drain valve 13e is opened.

[0036] Since the abatement 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 during a power loss is reduced compared to treating ammonia gas using only the water seal tank or only the scrubber tank, making it possible to reduce the capacity of the uninterruptible power supply.

[0037] In addition, a path is also provided at the bottom of the scrubber tank 13 for discharging ammonia water by gravity via the emergency drain valve 13f into the treated water storage tank 7 without passing through the circulation pump 14, the concentration meter 13a, and the heat exchanger 13b. When discharging 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 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] (Equipment startup) 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 to fill them with a certain amount of fresh water. The amount of water in the water seal tank 12 is detected by the liquid level gauge 12a.

[0040] (Operation flow) When the engine 3 is started, stopped, or stopped in an emergency, 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 just 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 have not dissolved 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 lower part to the upper part of the scrubber tank 13, and the concentration of the ammonia water is detected by the concentration meter 13a.

[0044] When the concentration of the ammonia water 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 discharge flow rate of the ammonia water from the scrubber tank 13 is detected by a flow meter. Fresh water equivalent to the discharged liquid volume 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 the 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 a predetermined condition for stopping the supply of the mixed gas to the detoxification device 6 is 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 piping 4, in the exhaust 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 ammonia water in the water seal tank 12 is drained by the drain pump 12e into the treated water storage tank 7. The ammonia water drained from the water seal tank 12 is confirmed by the concentration meter 12d to have 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 lower part to the upper part 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 a desired concentration, and is therefore 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 tank 12 is used for continuous treatment) The above-mentioned operation flow has been described as a so-called batch process in which after pouring water into the water seal tank 12, the mixed gas is supplied without pouring water or draining water, and then the supply of the mixed gas is stopped and then drained, but is not limited to this and continuous processing may also be performed. That is, the water tank 12 may be configured to detect the amount of the drained liquid by the liquid level gauge 12a while draining the ammonia water having reached the desired concentration, and to supply fresh water in an amount equivalent to the amount of the drained liquid, so that the liquid level position is maintained almost constant. In this case, the dissolution of the ammonia gas in the water tank 12 becomes a continuous process.

[0054] [Improvement (1) of the first embodiment] 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. This improved embodiment differs from the first embodiment in that ammonia gas volatilized in the treated water storage tank 7 is returned 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 stored ammonia water. 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 ammonia water. In this improved embodiment, however, the ammonia gas volatilizing in the treated water storage tank 7 is returned to the lower part 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, so there is no need to provide a drainage pump 12e, making it possible to reduce the size and power consumption of the device configuration. In addition, in the event of a power loss, by opening the emergency drain valve 13f, water can be drained from the scrubber tank 13 by gravity into the treated water storage tank 7 without passing through the circulation pump 14, concentration meter 13a, and heat exchanger 13b.

[0058] [Improvement (2) of the first embodiment] 3 is a block diagram showing the configuration of an ammonia gas treatment device according to an improved embodiment (2) of the first embodiment of the present invention. This improved embodiment differs from the first embodiment in that a pressurized buffer tank 16 is provided in the abatement device 6 as a measure against power loss. Therefore, in this improved embodiment, it is not necessary to provide an uninterruptible power supply.

[0059] In this improved embodiment, the fresh water introduced into the abatement device 6 is branched into three parts, and is supplied to the water seal tank 12 via the water seal tank water supply valve 12b, supplied to the upper part of the scrubber tank 13 via the scrubber tank water supply valve 13d, and 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 merges 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 the nitrogen gas from the nitrogen gas supply device 11 passes through the pressurizing valve 11a and is branched into two, and the nitrogen gas is supplied to pressurize the inside of the tank. The pressurized buffer tank 16 can be operated in two ways: first by putting fresh water in the tank and then by pressurizing it with nitrogen gas, inert gas, or air, and secondly by pressurizing the fresh water.

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

[0062] In the improved ammonia gas treatment device, at the start of treatment, the inlet valve 16a is opened in the pressurized buffer tank 16, and a certain amount of fresh water is stored in the fresh water tank 22, after which the inlet valve 16a is closed. The inside of the pressurized buffer tank 16 is kept under a constant pressure by the nitrogen gas from the nitrogen gas supply device 11, with the pressurizing valve 11a opened.

[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 by 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, the drainage water from the scrubber tank 13 can be discharged by opening the emergency drainage valve 13f and using the pressure in the pressurized buffer tank 16, even if the circulation pump 14 is not operating.

[0064] [Improvement (3) of the first embodiment] Fig. 4 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. This improved embodiment 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 measure against power loss. Therefore, this improved embodiment does not require 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 stored ammonia water. 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 ammonia water. In this improved embodiment, however, the ammonia gas volatilizing in the treated water storage tank 7 is returned to the lower part 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 drainage water from the water seal tank 12 can be sent to the treated water storage tank 7 by gravity, so there is no need to provide a drainage pump 12e, making it possible to reduce the size and power consumption of the device configuration.

[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 Fig. 5 is a block diagram showing the configuration of an ammonia gas treatment device according to a second embodiment of the present invention. The same reference numerals as in Figs. 1 to 4 denote the same configuration, and unless otherwise specified, the explanations in Figs. 1 to 4 are used and will not be repeated here.

[0070] In this embodiment, as shown in FIG. 5, the ammonia water generated 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 any of overflow, gravity, and the use of a drainage pump 12e.

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

[0073] The preferred concentration of the ammonia water sent to the neutralization treatment device 23 may be a concentration that allows neutralization by the acidic neutralizing agent. Since ammonia gas does not volatilize from the neutralized water stored in the neutralized 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 as well, as in the improvements (2) and (3) of the first embodiment, the abatement device 6 may be provided with a pressurized buffer tank 16 as a measure against power outages.

[0075] In this embodiment, the acid neutralizer stored in the acid neutralizer tank 8 may be any acidic substance capable of neutralizing ammonia water, and may be, for example, carbon dioxide or an organic acid such as citric acid, or any other acidic substance. 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, 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 and organic acids such as citric acid are preferred because they are easy and safe to handle, and no precipitates are produced 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 the stored acid neutralizer is sent to the piping to the neutralization treatment device 23 by this suction pump. A flow meter (not shown) is provided in the piping 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 according to the measurement result of this flow meter. The pump for pumping out the acid neutralizer may also be used as the pump for pumping out the 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 such as a blower (not shown). The amount of acid neutralizer supplied to the neutralization treatment device 23 is controlled by adjusting the flow control valve 9 according to the measurement result 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 from the acid neutralizer tank 8 by a transfer device such as a screw conveyor (not shown). In this case, the flow rate 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 according to the weighing result of a weight scale provided on the transfer path.

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

[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 rate control valve 9 according to the measurement result of a flow meter provided 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 if the sea area has no discharge regulations. In addition, the neutralized water may be sent to the selective reduction catalyst unit 17 to generate ammonia gas, and the ammonia gas may be used as a reducing agent. Carbon dioxide and organic acids such as citric acid are preferable as the neutralizing agent because they do not produce precipitates when used in the selective reduction catalyst unit 17.

[0082] The neutralized water storage tank 15 may be provided with a return pipe for sending out a portion of the neutralized water stored in the neutralized water storage tank 15 from the neutralized water storage tank 15 by a circulation pump and returning this neutralized water to the neutralization treatment device 23. If neutralization is not sufficient and neutralized water containing an ammonia component is sent to the neutralized water storage tank 15, this return pipe allows this neutralized water to be returned to the neutralization treatment device 23 for further neutralization. Also, if the pH value of the neutralized water sent to the neutralized water storage tank 15 is lower than 7 (acidic), the return pipe allows this neutralized water to be returned to the neutralization treatment device 23 and neutralized by mixing it with a liquid with a high pH value (basic) before neutralization.

[0083] When the neutralized water stored in the neutralized water storage tank 15 is sent to the selective catalytic reduction unit 17, the neutralized water is sent through a transport section 18 by a transport pump 18a to the selective catalytic reduction unit 17 connected to the exhaust duct of the engine 3. 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 denitrification treatment is performed by reacting with the above. The denitrified exhaust gas is discharged into the atmosphere. When the denitrification treatment is performed in the selective reduction catalyst 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 neutralized water can be reduced by generating ammonia gas from the neutralized water and using it in the selective reduction catalyst unit 17. In addition, it is no longer necessary to land the neutralized water, and it is also no longer necessary to discharge the neutralized water 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 generated ammonia gas in a ship carrying liquefied ammonia as cargo or engine fuel, adjust the concentration to a desired level, reduce the size of the storage tank, and reduce the storage space. [Explanation of symbols]

[0086] 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. Opening and closing valve 6 Abatement equipment 7 Treated water storage tank 8 Acid neutralizer tank 9. Flow Control Valve 10 Purge gas supply valve 11 Nitrogen gas supply device 11a Pressure valve 12 Water tank 12a Level gauge 12b Water seal tank water supply valve 12c Water seal tank drain valve 12d concentration meter 12e Drainage pump 13 Scrubber tank 13a Densitometer 13b Heat exchanger 13c Circulation 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 opening and closing valve 16b Outlet opening and closing valve 17 Selective catalytic reduction unit 18 Transportation Department 22 Fresh Water Tank 23 Neutralization treatment equipment

Claims

1. An apparatus for treating ammonia gas in a ship carrying liquefied ammonia as cargo or ship engine fuel, comprising: A detoxification device is provided for dissolving ammonia gas and / or ammonia water produced by dissolving the liquefied ammonia vaporized from the cargo or remaining in the fuel supply line of the engine in fresh water, The abatement device comprises: a water tank in which fresh water is stored, and ammonia gas obtained by vaporizing the liquefied ammonia and / or the ammonia gas is introduced from a lower portion thereof, and the ammonia gas is dissolved in the stored fresh water to produce ammonia water; a scrubber tank in which ammonia gas discharged from an upper portion of the water tank is introduced into a lower portion and fresh water is supplied to an upper portion of the water tank, and the ammonia gas is dissolved in the fresh water to produce ammonia water; A circulation pump that sends the ammonia water in the scrubber tank to an upper portion of the scrubber tank; a heat exchanger for cooling the ammonia water sent to the upper part of the scrubber tank by the circulation pump; have 2. An ammonia gas treatment device comprising:

2. A treated water storage tank is provided to store the ammonia water generated by the decontamination device, Ammonia gas volatilized from the treated water storage tank is introduced into the lower part of the scrubber tank.

2. The apparatus for treating ammonia gas according to claim 1.

3. A treated water storage tank is provided to store the ammonia water generated by the decontamination device, The treated water storage tank is a pressurized ammonia water storage tank.

2. The apparatus for treating ammonia gas according to claim 1.

4. a selective catalytic reduction unit into which exhaust gas from an engine of the ship is introduced, The selective catalytic reduction unit is supplied with the ammonia water produced in the detoxification device and performs denitrification of the exhaust gas.

2. The apparatus for treating ammonia gas according to claim 1.

5. a neutralization treatment device to which ammonia water is sent from the detoxification device, The neutralization treatment device neutralizes the ammonia water with an acidic neutralizing agent to produce neutralized water.

2. The apparatus for treating ammonia gas according to claim 1.

6. a selective catalytic reduction unit into which exhaust gas from an engine of the ship is introduced, The selective catalytic reduction unit is supplied with neutralized water produced by the neutralization treatment device and performs denitrification treatment of the exhaust gas.

6. The apparatus for treating ammonia gas according to claim 5.

7. 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 supply for driving the circulating pump, the fresh water is supplied to the upper part of the scrubber tank by the pressure in the pressurized buffer tank.

7. The ammonia gas treatment device according to claim 1,

8. The pressurized buffer tank is pressurized by a pressure source of ammonia gas produced by vaporizing 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.

8. The apparatus for treating ammonia gas according to claim 7.

9. An uninterruptible power supply that drives the circulating pump, When a power source for driving the circulating pump is lost, the circulating pump can be driven by the uninterruptible power source.

7. The ammonia gas treatment device according to claim 1,

10. A method for treating ammonia gas in a ship carrying liquefied ammonia as cargo or ship engine fuel, comprising the steps of: Sending ammonia gas and / or ammonia gas vaporized from liquefied ammonia volatilized from the cargo or remaining in the fuel supply line of the engine to a detoxification device; The abatement device comprises: a water tank in which fresh water is stored, and ammonia gas obtained by vaporizing the liquefied ammonia and / or the ammonia gas is introduced from a lower portion thereof, and the ammonia gas is dissolved in the stored fresh water to produce ammonia water; a scrubber tank in which ammonia gas discharged from an upper portion of the water tank is introduced into a lower portion and fresh water is supplied to an upper portion of the water tank, and the ammonia gas is dissolved in the fresh water to produce ammonia water; A circulation pump that sends the ammonia water in the scrubber tank to an upper portion of the scrubber tank; a heat exchanger for cooling the ammonia water sent to the upper part of the scrubber tank by the circulation pump; having The method includes a step of dissolving the liquefied ammonia in ammonia gas vaporized by the ammonia removal device and / or the ammonia gas in fresh water.

1. A method for treating ammonia gas comprising the steps of:

11. A treated water storage tank is provided. The ammonia water generated by the detoxification device is sent to the treated water storage tank and stored therein; The ammonia gas volatilized from the treated water storage tank is introduced into the lower part of the scrubber tank.

11. The method for treating ammonia gas according to claim 10.

12. A pressurized ammonia water storage tank is provided to store treated water. The ammonia water generated by the detoxification device is sent to the treated water storage tank and stored therein.

11. The method for treating ammonia gas according to claim 10.

13. A selective catalytic reduction unit is provided. The selective catalytic reduction unit is supplied with exhaust gas from the engine of the ship and ammonia water produced by the ammonia removal device, and performs denitrification of the exhaust gas.

11. The method for treating ammonia gas according to claim 10.

14. A neutralization treatment device is provided, The ammonia water generated by the detoxification device and an acid neutralizer are supplied to the neutralization treatment device, and the ammonia water is neutralized to produce neutralized water.

11. The method for treating ammonia gas according to claim 10.

15. A selective catalytic reduction unit is provided. The selective catalytic reduction unit is supplied with exhaust gas from the engine of the ship and neutralized water produced by the neutralization treatment device, and performs denitrification treatment of the exhaust gas.

15. The method for treating ammonia gas according to claim 14.

16. 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 upper portion of the scrubber tank by the pressure in the pressurized buffer tank.

16. The method for treating ammonia gas according to claim 10, wherein the ammonia gas is treated by a process for treating the ammonia gas.

17. 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 that purges the ammonia gas and sends it to the abatement device.

17. The method for treating ammonia gas according to claim 16.

18. providing an uninterruptible power supply for driving the circulating pump; When a power source for driving the circulating pump is lost, the circulating pump can be driven by the uninterruptible power source.

16. The method for treating ammonia gas according to claim 10, wherein the ammonia gas is treated by a process for treating the ammonia gas.

Images