Ammonia treatment systems and ships containing them

Abstract

This invention provides an ammonia treatment system for recovering and safely treating ammonia discharged when an ammonia-propelled vessel is stopped. [Solution] The ammonia treatment system according to the present invention includes a fuel storage unit for storing ammonia, a fuel supply unit that receives ammonia from the fuel storage unit and supplies ammonia to a customer, a fuel supply control unit provided between the fuel supply unit and the customer and shuts off the supply of ammonia, a buffer tank that receives ammonia from the fuel supply unit and stores it temporarily, a heater that receives ammonia from the buffer tank and heats it, and an oxidation catalyst unit that oxidizes the ammonia heated by the heater.

Description

Technical Field

[0001] The present invention relates to an ammonia treatment system and a ship including the same.

Background Art

[0002] Generally, ships are propelled using a diesel engine that generates driving force using diesel oil, a gas engine that generates driving force using gas such as LNG, a dual fuel engine that generates driving force using a mixture of diesel oil and gas, and the like.

[0003] Recently, as the demand for environmentally friendly / high-efficiency engines increases with the strengthening of IMO environmental regulations, research on propulsion systems using various fuels has been actively carried out.

[0004] Ammonia has attracted attention as an environmentally friendly fuel because it does not contain carbon, but it has characteristics that are relatively disadvantageous for combustion and use compared to conventionally used fuels.

[0005] For example, when using ammonia as a fuel, ammonia gas has lower combustion reactivity than other fuels and may contain unburned ammonia (ammonia slip) in the exhaust gas. Unburned ammonia is one of the toxic substances, and if discharged without treatment, it can cause environmental pollution or physical harm to the surrounding people.

[0006] In order to overcome the limitations of such ammonia fuels, it is necessary to develop a technology for safely treating ammonia gas.

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention was made to solve the problems of the conventional technology described above, and its purpose is to provide an ammonia treatment system for recovering and safely treating ammonia discharged when an ammonia-propelled vessel is stopped.

[0008] The problems addressed by this invention are not limited to those mentioned above, and other problems not mentioned should be clearly understood by those with ordinary skill from the description below. [Means for solving the problem]

[0009] An ammonia treatment system according to one embodiment of the present invention may include: a fuel storage unit for storing ammonia; a fuel supply unit for receiving ammonia from the fuel storage unit and supplying ammonia to a customer; a fuel supply control unit provided between the fuel supply unit and the customer for shutting off the supply of ammonia; a buffer tank for receiving ammonia from the fuel supply unit and temporarily storing it; a heater for receiving ammonia from the buffer tank and heating it; and an oxidation catalyst unit for oxidizing the ammonia heated by the heater.

[0010] Specifically, the buffer tank can receive ammonia from the fuel supply unit and temporarily store it when the supply of ammonia to the customer is normally stopped, and can adjust the amount of stored ammonia discharged.

[0011] Specifically, the system may further include an intake device that supplies outside air to the heater.

[0012] Specifically, the system may further include a heat exchanger that exchanges heat between the exhaust gas from the oxidation catalyst and the outside air supplied by the intake device.

[0013] An ammonia treatment system according to one embodiment of the present invention may include a fuel storage unit for storing ammonia, a fuel supply unit for receiving ammonia from the fuel storage unit and supplying ammonia to a customer, a fuel supply control unit provided between the fuel supply unit and the customer for shutting off the supply of ammonia, a buffer tank for receiving ammonia from the fuel supply unit and temporarily storing it, and a combustion unit for receiving ammonia from the buffer tank and burning it.

[0014] In one embodiment, the ammonia treatment system according to the present invention may further include an ammonia reforming catalyst unit that is disposed within the combustion unit to reform ammonia and generate hydrogen, and to supply the generated hydrogen to the combustion unit.

[0015] Specifically, the ammonia reforming catalyst unit can be supplied with ammonia from the fuel storage unit or a cargo tank that stores ammonia cargo.

[0016] Specifically, the system may further include a nitrogen oxide reduction device provided downstream of the combustion section to remove pollutants from the exhaust gas of the combustion section.

[0017] Specifically, the nitrogen oxide reduction device may be supplied with ammonia from at least one of the following: the fuel storage unit, the buffer tank, and the cargo tank for storing ammonia cargo.

[0018] Specifically, the flow rate of the reducing agent supplied to the nitrogen oxide reduction device without going through the buffer tank can be adjusted according to the flow rate or concentration of ammonia supplied to the nitrogen oxide reduction device from the buffer tank or the combustion unit.

[0019] Specifically, the device may further include an oxidation catalyst section located downstream of the nitrogen oxide reduction device, which oxidizes ammonia within the nitrogen oxide reduction device.

[0020] Specifically, it may further include an intake device that supplies outside air to the combustion section.

[0021] Specifically, when the supply of ammonia to the demand destination is normally stopped, the buffer tank receives ammonia from the fuel supply unit for temporary storage and can adjust the discharge amount of the stored ammonia.

[0022] Specifically, it may further include a fuel supply line connecting the fuel storage unit and the demand destination for supplying ammonia from the fuel storage unit to the demand destination, and a fuel recovery line connecting the fuel storage unit and the recovery tank for recovering ammonia from the demand destination to the recovery tank.

[0023] Specifically, it may further include a nitrogen purge line for supplying an inert gas to the fuel supply line or the fuel recovery line.

[0024] One embodiment of the present invention can provide a ship including the ammonia treatment system.

Advantages of the Invention

[0025] The ammonia treatment system according to the present invention can prevent environmental pollution caused by ammonia emissions by safely treating the ammonia released when stopping an ammonia propulsion ship.

[0026] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned should be clearly understood by those with ordinary knowledge from the description of the claims.

Brief Description of the Drawings

[0027] [Figure 1] FIG. 1 is a diagram showing an ammonia treatment system according to the first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an ammonia treatment system according to the second embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing an ammonia treatment system according to the third embodiment of the present invention. [Figure 4] Figure 4 shows an ammonia treatment system according to a fourth embodiment of the present invention. [Figure 5] Figure 5 shows an ammonia treatment system according to a fifth embodiment of the present invention. [Figure 6] Figure 6 shows an ammonia treatment system according to the sixth embodiment of the present invention. [Modes for carrying out the invention]

[0028] The object, particular advantages, and novel features of the present invention will become clearer from the following detailed description relating to the accompanying drawings and preferred embodiments. In this specification, when assigning reference numerals to components in each drawing, it should be noted that, to the extent possible, the same reference numerals are used for the same components, even if they appear in other drawings. Furthermore, in describing the present invention, if it is deemed that a specific explanation of related prior art would unnecessarily obscure the gist of the invention, such detailed explanation will be omitted.

[0029] In the following, when a part is said to "include" a certain component, unless otherwise stated, this does not exclude other components, but rather means that it may include other components.

[0030] In the following, "ammonia gas" or "ammonia fuel" can refer to a substance containing ammonia, and these terms can be used interchangeably. It should be clarified that ammonia gas is not necessarily limited to the gas phase based on its name, but may also be in the liquid phase.

[0031] Furthermore, the terms "ammonia, ammonia gas, gaseous ammonia, and liquid ammonia" below may include other components besides ammonia, such as impurities like lubricants and inert gases like nitrogen.

[0032] Furthermore, "upstream" and "downstream" in the following context are determined based on the direction in which the fluid flows through the pipe. For example, the point where the fluid begins to flow is upstream, and the point where the fluid arrives is downstream.

[0033] Although not shown in the drawings of this invention, pressure sensors PT, temperature sensors TT, valves, etc., can be provided in appropriate positions without limitation, and the measured values ​​from each sensor can be used in a variety of ways without limitation in the operation of the configuration described below.

[0034] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0035] Figure 1 shows an ammonia treatment system according to a first embodiment of the present invention.

[0036] Referring to Figure 1, the ammonia treatment system 1 may include a fuel storage unit 10, a fuel supply unit 20, a fuel supply control unit 30, and a demand destination 40.

[0037] The fuel storage unit 10 is a facility provided in the ammonia processing system 1 that can store ammonia, and can include any form of facility, and the fuel storage unit 10 may be a tank-type storage facility. The fuel storage unit 10 may be a facility for storing fuel, or a facility for storing cargo that is transported from the origin to the destination. The fuel or cargo stored in the fuel storage unit 10 may be ammonia.

[0038] In this specification, the term "ship" encompasses not only merchant vessels that transport cargo and people from their place of origin to their destination, but also offshore structures that float at a fixed point in the sea to perform specific tasks, as well as FSRUs, FPSOs, and bunkering vessels.

[0039] The fuel supply unit 20 is connected to one or more fuel storage units 10 and can heat ammonia to a temperature suitable for supply to the customer 40 and pressurize ammonia to a pressure suitable for supply to the customer 40. For example, ammonia having a pressure of 50 to 300 bar and a temperature of 10 to 50°C can be supplied to the customer 40. The fuel supply unit 20 may also be an LFSS (Low-flashpoint Fuel Supply System).

[0040] The fuel supply unit 20 consists of equipment such as a heater 21, a pump 22, a return cooler 23, and a recovery tank 24, as well as various valves and sensors for pressure regulation, flow rate regulation, venting, and nitrogen supply. It may also include, as auxiliary components, a service tank, a nitrogen supply system, a glycol system, a gas-liquid separator, and a vent mast.

[0041] The fuel supply control unit 30 is located between the fuel supply unit 20 and the customer 40, and when the fuel supply unit 20 malfunctions in the fuel supply line L1, it can effectively shut off the fuel supply to the customer 40 by separating the fuel supply unit 20 from the customer 40. The fuel supply control unit 30 may consist of valves and filters for purposes such as double shutoff and discharge, venting, pressure regulation, and nitrogen supply, as well as various sensors. The fuel supply control unit 30 is a mechanism in which control valves that control the supply of ammonia to the customer 40 are centrally located, and may also be a fuel valve train (FVT).

[0042] The customer 40 can be an ammonia propulsion engine that uses ammonia to propel a ship, or an ammonia power generation engine that produces electricity for use on a ship.

[0043] The fuel recovery line L2 connects the demand destination 40 and the recovery tank 24, allowing excess ammonia that is not burned at the demand destination 40 to be transferred to the recovery tank 24 via the fuel recovery line L2. Such excess ammonia can have a pressure of 50 to 300 bar.

[0044] The recovery tank 24 can separate the excess ammonia recovered from the demand site 40 into liquid ammonia LA and gaseous ammonia GA. If the gaseous liquefied gas flows into the pump 22, there is a risk of cavitation problems. Therefore, the liquefied gas flowing along the fuel recovery line L2 is separated into gas and liquid phases as it passes through the recovery tank 24, thereby preventing the inflow of gaseous ammonia GA into the pump 22.

[0045] The liquid ammonia LA separated by the recovery tank 24 can be recovered in the fuel recovery line L2. The fuel recovery line L2 may be equipped with a return cooler 23 for cooling the liquid ammonia LA. The liquid ammonia LA can be transferred to the fuel recovery line L2 via a recovery tank line L3 that connects the recovery tank 24 and the fuel recovery line L2. For example, if the liquid level in the recovery tank 24 is measured by a liquid level gauge in the recovery tank 24 to have reached a set height, the ammonia can be returned via the recovery tank line L3. Since the liquid ammonia LA contains impurities such as lubricating oil, these impurities can also be transferred to the recovery tank line L3.

[0046] Although not shown in the drawings, a line connecting the recovery tank 24 and the fuel storage unit 10 may be provided, and ammonia can be directly transferred from the recovery tank 24 to the fuel storage unit 10 using this line.

[0047] In this way, excess ammonia that remains unburned at the demand destination 40 can be recovered, and the liquid phase liquid ammonia LA separated by the recovery tank 24 can be supplied again to the fuel recovery line L2.

[0048] Furthermore, the gaseous ammonia GA separated by the recovery tank 24 can be transferred to the buffer tank 50 via the vent line L4. The buffer tank 50 can temporarily store the gaseous ammonia GA.

[0049] The ammonia fuel supply may be shut down in an emergency when an emergency situation occurs, such as a fuel leak, fire, or equipment failure, making it difficult to supply ammonia fuel normally. Conversely, the ammonia fuel supply may be shut down normally when it is not needed, such as when the customer 40 is not operating, even though the ammonia fuel supply is functioning normally. When the ammonia fuel supply is shut down in this way, it is necessary to recover ammonia fuel from the fuel supply unit 20, the fuel supply control unit 30, the customer 40, etc.

[0050] When the ammonia fuel supply is normally shut off, some of the ammonia fuel from the fuel supply line L1 and fuel recovery line L2 is returned to the recovery tank 24. At this time, nitrogen is injected via the nitrogen purge line L5 to purge any remaining ammonia in the fuel supply line L1 and fuel recovery line L2 into the recovery tank 24. The nitrogen gas and ammonia gas in the recovery tank 24 flow into the buffer tank 50 via the vent line L4. In the buffer tank 50, ammonia contained in the discharged gas can be collected, and ammonia, nitrogen, oil, etc. can be separated. It can be connected to a vent mast (not shown) to discharge nitrogen gas, etc., into the atmosphere.

[0051] The ammonia in the buffer tank 50 can be transmitted to the customer 40 when the customer 40 is operational (when the ammonia supply is operational) and incinerated at the customer 40. Preferably, it can be mixed with intake air supplied from the intake air supply unit 60 and supplied to the customer 40.

[0052] The flow rate of ammonia supplied to the customer 40 is preferably small compared to the intake volume (intake flow rate) of outside air supplied from the intake supply unit 60. For example, the flow rate of ammonia supplied to the customer 40 is 0.01% to 1.0% by weight of the intake volume of outside air supplied from the intake supply unit 60, and preferably about 0.05% to 0.5% by weight. The flow rate of ammonia supplied to the customer 40 is preferably adjusted to be lower than the lower explosion limit (LEL) of ammonia (the minimum gas concentration at which ammonia can explode) when mixed with outside air.

[0053] When the ammonia fuel supply is normally shut off, the buffer tank 50 can temporarily store ammonia, and the flow rate of ammonia discharged from the buffer tank 50 can be adjusted. In other words, when the supply of ammonia to the customer 40 is normally shut off, the buffer tank 50 can receive ammonia from the fuel supply unit 10 and temporarily store it, and can adjust the amount of ammonia supplied when ammonia is supplied. The ammonia in the buffer tank 50 is supplied to the customer 40 in small quantities, and the small amount of ammonia can be incinerated by the customer 40.

[0054] When the ammonia fuel supply is normally shut off, any ammonia remaining in the fuel supply line L1, fuel recovery line L2, etc., can be transferred to a treatment facility (not shown) for treatment. The treatment facility (not shown) can reduce the concentration of ammonia and discharge it to the outside.

[0055] The ammonia fuel supply can be emergency-stopped in the event of an emergency such as a fuel leak, fire, or equipment failure. In this case, for safety reasons, the ammonia fuel will not be supplied to or returned from the customer 40. That is, the valves on the fuel supply line L1 and fuel recovery line L2 can be closed. At this time, the valve on the emergency stop line L6 will be opened. Ammonia discharged through the emergency stop line L6 can be treated by a knockout drum, recovery tank, scrubber, or absorption tank. The equipment used to treat ammonia discharged through the emergency stop line L6 is merely an example and is not limited to this.

[0056] Some of the ammonia accumulated in the fuel supply line L1 and fuel recovery line L2 can be transferred to a separately provided ammonia gas after-treatment unit (not shown) for processing.

[0057] An ammonia gas after-treatment unit (not shown) can reduce the concentration of ammonia. The gas treated in the ammonia gas after-treatment unit (not shown) can be emergency discharged to the outside via a vent mast (not shown). The ammonia gas after-treatment unit (not shown) can be an ammonia absorption device such as a scrubber or absorption tank, or an ammonia oxidation device that oxidizes ammonia using air. A scrubber is a device that sprays water, an absorbent, etc., into the contaminated gas drawn into the scrubber so that the contaminants are absorbed and removed by the absorbent, and the ammonia gas can be released into the atmosphere after being removed in the ammonia gas after-treatment unit (not shown). The scrubber may include a packing section, in which water, etc., is sprayed at the top of the scrubber and ammonia gas is injected at the bottom of the scrubber so that the water and ammonia gas come into contact at the packing section and the ammonia gas is absorbed by the water. The vent gas from which the ammonia gas has been removed can be discharged to the outside from the top of the scrubber, and the ammonia water collected at the bottom of the scrubber can be discharged to the outside from the bottom of the scrubber.

[0058] For example, the ammonia gas aftertreatment unit may include an oxidation catalyst unit 110 for oxidizing ammonia and / or a nitrogen oxide reduction device 70 for removing pollutants in the exhaust gas.

[0059] An absorption tank is a storage facility that stores water, absorbent materials, etc., above a certain water level. When ammonia gas is injected directly into the absorption tank, the ammonia can be absorbed by the absorbent material stored in the tank.

[0060] An ammonia oxidation apparatus can oxidize ammonia using air. The ammonia oxidation apparatus contains an ammonia oxidation catalyst, and ammonia can be removed by reacting with air in the ammonia oxidation catalyst (ammonia reforming catalyst).

[0061] Ammonia absorbers can be used when ammonia emissions are high, but they must be used to treat the wastewater generated during the ammonia absorption process. Ammonia oxidizers can be used when ammonia emissions are controlled to a small level, but they do not generate wastewater after ammonia oxidation. In the event of an emergency shutdown of the ammonia fuel supply, it is preferable to use an ammonia absorber that can process large amounts of ammonia in a short time.

[0062] When the liquid pressure in the fuel supply line L1 and fuel recovery line L2 is released, nitrogen is supplied via the nitrogen purge line L5, purging any remaining liquid ammonia in the fuel supply line L1 and fuel recovery line L2 into the recovery tank 24. The nitrogen gas and ammonia gas in the recovery tank 24 flow into the buffer tank 50 via the vent line L4. In the buffer tank 50, ammonia contained in the discharged gas can be collected and suctioned, and ammonia, nitrogen, oil, etc. can be separated. It can be connected to a vent mast (not shown) to discharge nitrogen gas, etc., into the atmosphere.

[0063] Figure 2 shows an ammonia treatment system according to a second embodiment of the present invention. Parts common to Figure 1 may be omitted from the following description.

[0064] Referring to Figure 2, exhaust gas emitted from the customer 40 can be transmitted along the exhaust gas line L7 to the nitrogen oxide reduction device 70. The nitrogen oxide reduction device 70 can remove nitrogen oxides contained in the exhaust gas by reducing nitrogen oxides NOx. Such a nitrogen oxide reduction device 70 may be a selective catalytic reduction (SCR) device. The nitrogen oxide reduction device 70 is not limited to removing only nitrogen oxides NOx as its name suggests, but can also remove pollutants such as sulfur oxides SOx and carbon dioxide CO2.

[0065] A reducing agent can be supplied to the nitrogen oxide reduction device 70. For example, ammonia can be used as the reducing agent. The ammonia treatment system 1 according to the second embodiment of the present invention stores ammonia in the fuel storage unit 10, so it does not need to be equipped with a separate ammonia generating device or ammonia storage device for removing nitrogen oxides. However, the present invention is not limited thereto and may include a separate ammonia storage device or generating device.

[0066] When the ammonia fuel supply is normally shut off, the nitrogen oxide reduction device 70 receives gaseous ammonia GA from the buffer tank 50 and can remove the ammonia by reacting the received ammonia with nitrogen oxides.

[0067] When the customer 40 is operational, the exhaust gas discharged from the customer 40 and the gaseous ammonia GA transmitted from the buffer tank 50 can be mixed in the nitrogen oxide reduction device 70. At this time, the nitrogen oxide reduction device 70 can react the nitrogen oxides contained in the exhaust gas with ammonia to oxidize the ammonia. The ammonia oxidation reaction equation is as shown below, and the oxidation reaction can occur with a catalyst under temperature conditions of 200°C or higher.

[0068] [Formula 1] 4NO+4NH3→4N2+6H2O

[0069] The flow rate of ammonia supplied to the nitrogen oxide reduction device 70 is preferably small compared to the flow rate of the exhaust gas. For example, the flow rate of ammonia supplied to the nitrogen oxide reduction device 70 is 0.01% to 1.0% by weight of the exhaust gas flow rate, preferably about 0.05% to 0.5% by weight.

[0070] The buffer tank 50 can temporarily store ammonia, and the flow rate of ammonia discharged from the buffer tank 50 can be adjusted. Therefore, a small amount of ammonia can be supplied to the nitrogen oxide reduction device 70. Because only a small amount of ammonia can be supplied, the ammonia treatment system 1 does not have sufficient capacity for large-scale processing, but the ammonia can be processed by the nitrogen oxide reduction device 70 installed on existing ships.

[0071] A gas measuring instrument GD and a flow meter FT may be provided between the buffer tank 50 and the nitrogen oxide reduction device 70. A portion of the ammonia transmitted from the buffer tank 50 to the nitrogen oxide reduction device 70 is transmitted to the gas measuring instrument GD as a sample for confirming the ammonia concentration, and the ammonia concentration can be confirmed in the gas measuring instrument GD.

[0072] The flow meter FT allows monitoring of the ammonia discharge rate from the buffer tank 50. At this time, since the nitrogen oxide reduction device 70 has a limited processing capacity, the flow control valve FV can adjust the flow rate of ammonia transmitted from the buffer tank 50 to the nitrogen oxide reduction device 70 according to the ammonia discharge rate and ammonia concentration in the buffer tank 50. Furthermore, the amount of reducing agent supplied to the nitrogen oxide reduction device 70 without passing through the buffer tank 50 can be adjusted according to the ammonia discharge rate and ammonia concentration in the buffer tank 50. The higher the ammonia discharge rate and ammonia concentration in the buffer tank 50, the less reducing agent can be supplied to the nitrogen oxide reduction device 70 without passing through the buffer tank 50.

[0073] Ammonia from the fuel storage unit 10 or a cargo tank (not shown) that stores ammonia as cargo can be supplied to the nitrogen oxide reduction device 70 as a reducing agent without going through the buffer tank 50. However, the present invention is not limited thereto, and the reducing agent can be supplied from a separate reducing agent supply facility. Here, as the reducing agent, any substance used to reduce nitrogen oxides, including ammonia, can be used without limitation.

[0074] Although not shown in the diagram, a portion of the gaseous ammonia GA discharged from the buffer tank 50 can be supplied to the customer 40 for combustion, and the remainder can be supplied to the nitrogen oxide reduction device 70 for oxidation.

[0075] Figure 3 shows an ammonia treatment system according to a third embodiment of the present invention.

[0076] Referring to Figure 3, the knockout drum 80 is located downstream of the recovery tank 24, and gaseous ammonia GA discharged from the recovery tank 24 can be transferred to the knockout drum 80. Although not shown in the drawing, as an example, the knockout drum 80 can be located downstream of the buffer tank 50, and gaseous ammonia GA can be supplied from the recovery tank 24 to the buffer tank 50, and the knockout drum 80 can be supplied with gaseous ammonia GA from the buffer tank 50.

[0077] The knockout drum 80 can receive fuel recovered from the recovery tank 24 when the ammonia fuel supply is normally shut off, and filter out impurities (such as lubricating oil) contained in the fuel. In addition to the gaseous ammonia GA separated in the recovery tank 24, liquid ammonia LA that is transmitted to the recovery tank line L3 can also be transmitted to the knockout drum 80.

[0078] Furthermore, in the event of an emergency shutdown of the ammonia fuel supply, the knockout drum 80 can receive ammonia recovered from the fuel supply line L1 and fuel recovery line L2 via the emergency shutdown line L6, and filter out impurities (such as lubricating oil) contained in the ammonia.

[0079] An inert gas supply unit (not shown) can supply inert gases such as nitrogen gas (N2) and carbon dioxide gas (CO2) to the fuel supply line L1 and fuel recovery line L2 via a nitrogen purge line L5. The inert gas supply unit (not shown) is configured to supply inert gas and may include a device for generating inert gas and a device for storing inert gas. The inert gas is supplied to the fuel supply line L1 and fuel recovery line L2, allowing residual fuels such as ammonia in the fuel supply line L1 and fuel recovery line L2 to be discharged to the knockout drum 80 or recovery tank 24.

[0080] The knockout drum 80 can separate ammonia and lubricating oil by discharging ammonia in the gas phase and lubricating oil in the liquid phase. To promote the vaporization of ammonia, the knockout drum 80 can use a heating element (not shown), such as tracing, which may use a medium such as steam or seawater as a heat source, or it may be configured to heat using electricity.

[0081] The knockout drum 80 transmits gaseous ammonia to the ammonia processing unit 90, and the lubricating oil and liquid ammonia separated from it can be recovered at the bottom along the knockout drum line L8 to the recovery tank 24.

[0082] The ammonia processing unit 90 may include a cargo tank 91, a compressor 92, a condenser 93, and a receiver 94, and the ammonia processing unit 90 may also be a reliquefaction unit provided for liquefying evaporated gas generated in the cargo storage tank or fuel storage tank of an existing ship.

[0083] The gaseous ammonia GA discharged from the knockout drum 80 is supplied to the cargo tank 91, where it can be liquefied along with the evaporated gas from the cargo tank 91 as it passes through the compressor 92 and condenser 93 in the reliquefaction line L9. In the receiver 94, the liquefied ammonia is separated, and the separated liquid ammonia LA can be returned to the cargo tank 91. At this time, inert gases such as nitrogen supplied for purging the fuel supply line L1 and fuel recovery line L2 can be discharged to the outside from the receiver 94.

[0084] In Figure 3, it was explained that gaseous ammonia GA from the knockout drum 80 is transmitted to the cargo tank 91 and liquefied using the reliquefaction device in the cargo tank 91. However, the gaseous ammonia GA from the knockout drum 80 can also be transmitted to the fuel storage unit 10 and liquefied using the reliquefaction device in the fuel storage unit 10.

[0085] Figure 4 shows an ammonia treatment system according to a fourth embodiment of the present invention.

[0086] Referring to Figure 4, the gaseous ammonia GA separated by the recovery tank 24 can be transferred to the buffer tank 50 via the vent line L4. The buffer tank 50 can temporarily store ammonia, and the flow rate of ammonia discharged from the buffer tank 50 is adjustable.

[0087] Ammonia in the buffer tank 50 can be transferred to the heater 100, which can heat the transferred ammonia and the outside air supplied by the intake device 120. The heater 100 may use a medium such as steam or seawater as a heat source, or it may be configured to heat using electricity, and it may be a catalytic heater or a heat transfer heater, but is not limited to these.

[0088] Ammonia that has passed through heater 100 can be transferred to oxidation catalyst section 110. Oxidation catalyst section 110 can oxidize ammonia using an oxidation catalyst (AOC). The oxidation catalyst can be active at approximately 250-350°C, and heater 100 can heat ammonia and ambient air within the temperature range in which the oxidation reaction can occur in oxidation catalyst section 110 (the temperature range in which the oxidation catalyst is active).

[0089] The intake device 120 is a device that draws in outside air, such as a fan, and can supply outside air to the heater 100 along the outside air line L10. The outside air can be mixed with ammonia and supplied to the oxidation catalyst section 110.

[0090] Figure 5 shows an ammonia treatment system according to a fifth embodiment of the present invention. Parts common to Figure 4 will not be explained below.

[0091] Referring to Figure 5, the ammonia in the buffer tank 50 can be transferred to the heater 100, which can heat the transferred ammonia and the outside air supplied by the intake device 120.

[0092] The intake device 120 can supply outside air to the heater 100 along the outside air line L10. At this time, a heat exchanger 130 may be provided downstream of the oxidation catalyst unit 110 so that the outside air supplied from the intake device 120 is heat-exchanged with the exhaust gas discharged from the oxidation catalyst unit 110. In other words, the outside air can be preheated as it passes through the heat exchanger 130 before being transferred to the heater 100.

[0093] By using the waste heat from the exhaust gas discharged from the oxidation catalyst unit 110 to preheat the outside air, the energy consumption required for heating ammonia and the outside air in the heater 100 can be reduced.

[0094] In one embodiment, the ammonia treatment system according to the present invention may further include an ammonia reforming catalyst unit that is disposed within the combustion unit to reform ammonia and generate hydrogen, and to supply the generated hydrogen to the combustion unit. Figure 6 shows an ammonia treatment system according to a sixth embodiment of the present invention.

[0095] Referring to Figure 6, gaseous ammonia GA from the buffer tank 50 can be transferred to the combustion section 140. The combustion section 140 may be equipped with an ammonia reforming catalyst section 141. The reforming catalyst section 141 may contain any catalyst that can be used to reform ammonia, preferably a nickel catalyst. The reforming catalyst section 141 is active at approximately 850 to 950°C, and ammonia can be reformed within this temperature range.

[0096] The combustion unit 140 can be extinguished by ammonia supplied from the buffer tank 50. At this time, the ammonia supplied to the combustion unit 140 is mixed with nitrogen supplied for purging the fuel supply line L1 and fuel recovery line L2, and since ammonia itself has a high ignition point, it is difficult to extinguish the ammonia. Therefore, the ammonia reforming catalyst unit 141 can generate hydrogen by thermally decomposing ammonia to help the combustion of ammonia in the combustion unit 140, and supply the hydrogen to the combustion unit 140. The combustion unit 140 can forcibly extinguish the ammonia by mixing it with hydrogen.

[0097] The ammonia reforming catalyst section 141 is equipped with an ammonia reforming catalyst, and since the ammonia reforming catalyst is active at high temperatures, the ammonia reforming catalyst section 141 can be placed inside the combustion section 140 where combustion occurs in order to maintain the ammonia reforming catalyst section 141 at a high temperature.

[0098] In the initial stages of operation of the ammonia reforming catalyst unit 141, gaseous ammonia GA can be supplied as pilot fuel via the pilot fuel line L11 for spark generation or initial ignition. The gaseous ammonia GA can be supplied to the ammonia reforming catalyst unit 141 from a facility where ammonia is stored, such as the fuel storage unit 10 or the cargo tank 91, but the present invention is not limited thereto.

[0099] The intake device 120 can supply outside air to the combustion section 140 along the outside air line L10. The outside air is mixed with ammonia and hydrogen, and the mixed gas can be burned in the combustion section 140.

[0100] The combustion section 140 is connected to a nitrogen oxide reduction device 70 and an oxidation catalyst section 110. The exhaust gas is first treated in the nitrogen oxide reduction device 70 and then secondarily treated in the oxidation catalyst section 110. More specifically, the nitrogen oxide reduction device 70 can remove ammonia by reacting pollutants such as nitrogen oxides and sulfur oxides with ammonia.

[0101] Since the nitrogen oxide reduction device 70 has a limited processing capacity, the flow rate of ammonia transmitted from the buffer tank 50 to the nitrogen oxide reduction device 70 can be adjusted according to the ammonia discharge volume and ammonia concentration of the buffer tank 50 and the combustion unit 140. Furthermore, the amount of reducing agent supplied to the nitrogen oxide reduction device 70 without passing through the buffer tank 50 can be adjusted according to the ammonia discharge volume and ammonia concentration of the buffer tank 50 and the combustion unit 140. The higher the ammonia discharge volume and ammonia concentration of the buffer tank 50, the less reducing agent can be supplied to the nitrogen oxide reduction device 70 without passing through the buffer tank 50.

[0102] In the oxidation catalyst section 110, excess ammonia can be removed. The combustion section 140 can heat ammonia and ambient air within a temperature range in which the oxidation reaction can occur in the oxidation catalyst section 110.

[0103] By using the waste heat from the exhaust gas discharged from the oxidation catalyst unit 110 to preheat the outside air, the energy consumption required for heating ammonia and the outside air in the heater 100 can be reduced.

[0104] Thus, the ammonia treatment system 1 according to the present invention can safely recover the ammonia discharged when the fuel supply is normally or in an emergency.

[0105] Furthermore, since the ammonia treatment system 1 according to the present invention can treat ammonia using engines, nitrogen oxide reduction devices, and reliquefaction devices that are conventionally installed in ships, it is possible to avoid incurring additional costs for installing ammonia treatment equipment.

[0106] Furthermore, the ammonia treatment system 1 according to the present invention can temporarily store ammonia in the buffer tank 50 when the fuel supply is normally stopped, and can adjust the flow rate of ammonia discharged from the buffer tank 50. Therefore, it is possible to treat ammonia using an engine, nitrogen oxide reduction device, and oxidation catalyst that cannot process large amounts of ammonia in a short period of time.

[0107] Furthermore, the ammonia treatment system 1 according to the present invention can safely treat ammonia using the ammonia treatment unit 90 conventionally provided in ships, not only when the ammonia fuel supply is normally stopped, but also when an emergency stop occurs and a large amount of ammonia is discharged.

[0108] Furthermore, the ammonia treatment system 1 according to the present invention is equipped with a heater 100 to adjust the temperature conditions of the oxidation catalyst section 110, and by using the waste heat of the exhaust gas discharged from the oxidation catalyst section 110 to preheat the outside air supplied to the heater 100, the amount of energy consumed to heat the heater 100 can be reduced.

[0109] Furthermore, the ammonia treatment system 1 according to the present invention can reduce the energy consumed to heat the ammonia reforming catalyst section 141 by arranging the ammonia reforming catalyst section 141 within the combustion section 140 in order to match the temperature conditions of the reforming catalyst within the ammonia reforming catalyst section 141.

[0110] Furthermore, the ammonia treatment system 1 according to the present invention includes an oxidation catalyst section 110 downstream of the combustion section 140, which allows the oxidation catalyst section 110 to oxidize the ammonia heated in the combustion section 140 without further heating.

[0111] The present invention is not limited to the embodiments described above, and of course, other embodiments may include combinations of the embodiments or combinations of at least one of the embodiments with known technology.

[0112] Although the present invention has been described in detail above with reference to specific embodiments, this is merely for the purpose of explaining the present invention in detail, and it is obvious that the present invention is not limited thereto, and that modifications and improvements can be made within the scope of the technical idea of ​​the present invention by those with ordinary skill in the art.

[0113] Any simple modifications or changes to the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention is defined by the appended claims. [Industrial applicability]

[0114] The ammonia treatment system according to the present invention can prevent environmental pollution caused by ammonia emissions by safely treating the ammonia released when an ammonia-propelled vessel is stopped.

Claims

1. A fuel storage unit for storing ammonia, A fuel supply unit that receives ammonia from the fuel storage unit and supplies ammonia to the customer, A fuel supply control unit is provided between the fuel supply unit and the customer, which shuts off the supply of ammonia, A heater that receives ammonia recovered from the aforementioned customer and heats it via an external heat source, An ammonia treatment system comprising an ammonia gas post-treatment unit for post-treating ammonia heated by the heater.

2. The system further includes a buffer tank for temporarily storing ammonia recovered from the aforementioned customer and transmitted from the fuel supply unit, The heater receives ammonia from the buffer tank, The buffer tank is The ammonia treatment system according to claim 1, wherein when the supply of ammonia to the aforementioned demand destination is normally stopped, ammonia is transmitted from the fuel supply unit and temporarily stored, and the amount of stored ammonia discharged is adjusted.

3. The ammonia treatment system according to claim 1, further comprising an intake device for supplying outside air to the heater.

4. The ammonia gas post-treatment unit includes an oxidation catalyst unit for oxidizing ammonia, The ammonia treatment system according to claim 3, further comprising a heat exchanger for exchanging heat between the exhaust gas from the oxidation catalyst and the outside air supplied by the intake device.

5. A fuel storage unit for storing ammonia, A fuel supply unit that receives ammonia from the fuel storage unit and supplies ammonia to the customer, A fuel supply control unit is provided between the fuel supply unit and the customer, which shuts off the supply of ammonia, A combustion unit that receives and burns ammonia recovered from the aforementioned customer, An ammonia treatment system comprising an ammonia gas post-treatment unit for post-treating residual ammonia after it has passed through the combustion unit.

6. The ammonia treatment system according to claim 5, further comprising an ammonia reforming catalyst unit disposed within the combustion unit for reforming ammonia to produce hydrogen and supplying the produced hydrogen to the combustion unit.

7. The ammonia reforming catalyst section is, The ammonia treatment system according to claim 6, wherein ammonia is supplied from the fuel storage unit or a cargo tank for storing ammonia cargo.

8. The ammonia gas aftertreatment unit is A nitrogen oxide reduction device is provided downstream of the combustion section to remove pollutants from the exhaust gas of the combustion section, The ammonia treatment system according to claim 5, further comprising an oxidation catalyst unit for oxidizing the ammonia gas.

9. The system further includes a buffer tank for temporarily storing ammonia recovered from the aforementioned customer and transmitted from the fuel supply unit, The nitrogen oxide reduction device is The ammonia treatment system according to claim 8, wherein ammonia is supplied from at least one of the fuel storage unit, the buffer tank, and the cargo tank for storing ammonia cargo.

10. The ammonia treatment system according to claim 9, wherein the flow rate of a reducing agent supplied to the nitrogen oxide reduction device without going through the buffer tank is adjusted according to the flow rate or concentration of ammonia supplied to the nitrogen oxide reduction device from the buffer tank or the combustion unit.

11. The ammonia treatment system according to claim 8, wherein the oxidation catalyst is provided downstream of the nitrogen oxide reduction device and oxidizes ammonia in the nitrogen oxide reduction device.

12. The ammonia treatment system according to claim 5, further comprising an intake device for supplying outside air to the combustion section.

13. The system further includes a buffer tank for temporarily storing ammonia recovered from the aforementioned customer and transmitted from the fuel supply unit, The buffer tank is The ammonia treatment system according to claim 5, wherein when the supply of ammonia to the aforementioned customer is normally stopped, ammonia is transmitted from the fuel supply unit and temporarily stored, and the amount of stored ammonia discharged is adjusted.

14. A fuel supply line connects the fuel storage unit and the customer, and supplies ammonia from the fuel storage unit to the customer. The ammonia treatment system according to claim 5, further comprising a fuel recovery line that connects the fuel storage unit and the recovery tank, and recovers ammonia from the customer to the recovery tank.

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