Ammonia processing system and ship including same

Abstract

The present disclosure relates to an ammonia treatment system, and may include a fuel storage unit configured to store ammonia; a fuel supply unit configured to receive the ammonia from the fuel storage unit and supply the ammonia to a demand destination; a fuel supply control unit provided between the fuel supply unit and the demand destination and configured to cut off a supply of the ammonia; a buffer tank configured to receive and temporarily store the ammonia from the fuel supply unit; a heater configured to receive and heat the ammonia from the buffer tank; and an oxidation catalyst unit configured to oxidize the ammonia heated by the heater.

Description

TECHNICAL FIELD

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

[0002] In general, ships are propelled using diesel engines that produce propulsive power using diesel oil, gas engines that produce propulsive power using gases such as LNG, and dual-fuel engines that produce propulsive power using a combination of diesel oil and gas.

[0003] Recently, with the growing demand for environmentally friendly / highly efficient engines due to stricter IMO environmental regulations, research on propulsion systems using various fuels is actively underway.

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

[0005] For example, when ammonia is used as fuel, ammonia gas has a lower combustion reactivity than other fuels, and thus, its exhaust gas may contain unburned ammonia (ammonia slip), and unburned ammonia is one of toxic substances and can cause environmental pollution or physical harm to nearby people if released without treatment.

[0006] In order to overcome these limitations of ammonia fuel, there is a need to develop technology for safely treating ammonia gas.SUMMARY TECHINCL OBJECTS

[0007] The present disclosure has been created to solve the problems of the prior art as described above, and it is an object of the present disclosure to provide an ammonia treatment system for recovering and safely treating ammonia discharged when an ammonia-propelled ship is stopped.

[0008] The objects of the present disclosure are not limited to those described above, and other objects that have not been mentioned will be clearly understood by those skilled in the art from the description below.TECHNICAL SOLUTION

[0009] An ammonia treatment system according to one embodiment of the present disclosure may include a fuel storage unit configured to store ammonia; a fuel supply unit configured to receive the ammonia from the fuel storage unit and supply the ammonia to a demand destination; a fuel supply control unit provided between the fuel supply unit and the demand destination and configured to cut off a supply of the ammonia; a buffer tank configured to receive and temporarily store the ammonia from the fuel supply unit; a heater configured to receive and heat the ammonia from the buffer tank; and an oxidation catalyst unit configured to oxidize the ammonia heated by the heater.

[0010] Specifically, the buffer tank may receive the ammonia from the fuel supply unit, temporarily store the ammonia, and adjust a discharge amount of the stored ammonia when the supply of the ammonia to the demand destination is stopped normally.

[0011] Specifically, an intake device configured to supply external air to the heater may be further included.

[0012] Specifically, a heat exchanger configured to exchange heat between an exhaust gas from the oxidation catalyst unit and the external air supplied by the intake device may be further included.

[0013] An ammonia treatment system according to one embodiment of the present disclosure may include a fuel storage unit configured to store ammonia; a fuel supply unit configured to receive the ammonia from the fuel storage unit and supply the ammonia to a demand destination; a fuel supply control unit provided between the fuel supply unit and the demand destination and configured to cut off a supply of the ammonia; a buffer tank configured to receive and temporarily store the ammonia from the fuel supply unit; and a combustion unit configured to receive and combust the ammonia from the buffer tank.

[0014] In one example, the ammonia treatment system according to the present disclosure may further include an ammonia reforming catalyst unit disposed within the combustion unit, and configured to produce hydrogen by reforming the ammonia and supply the produced hydrogen to the combustion unit.

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

[0016] Specifically, a nitrogen oxide reduction device provided downstream of the combustion unit and configured to remove pollutants in an exhaust gas from the combustion unit may be further included.

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

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

[0019] Specifically, an oxidation catalyst unit provided downstream of the nitrogen oxide reduction device and configured to oxidize ammonia in the nitrogen oxide reduction device may be further included.

[0020] Specifically, an intake device configured to supply external air to the combustion unit may be further included.

[0021] Specifically, the buffer tank may receive the ammonia from the fuel supply unit, temporarily store the ammonia, and adjust a discharge amount of the stored ammonia when the supply of the ammonia to the demand destination is stopped normally.

[0022] Specifically, a fuel supply line connecting the fuel storage unit and the demand destination and configured to supply the ammonia from the fuel storage unit to the demand destination; and a fuel recovery line connecting the fuel storage unit and a recovery tank and configured to recover the ammonia from the demand destination to the recovery tank may be further included.

[0023] Specifically, a nitrogen purge line configured to supply an inert gas to the fuel supply line or the fuel recovery line may be further included.

[0024] One embodiment of the present disclosure may provide a ship including the ammonia treatment system.EFFECTS OF THE DISCLOSURE

[0025] The ammonia treatment system according to the present disclosure can prevent environmental pollution caused by ammonia release by safely treating ammonia released when an ammonia-propelled ship is stopped.

[0026] The effects of the present disclosure are not limited to those mentioned above, and other effects that have not been mentioned will be clearly understood by those skilled in the art from the description of the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a diagram showing an ammonia treatment system according to a first embodiment of the present disclosure; FIG. 2 is a diagram showing an ammonia treatment system according to a second embodiment of the present disclosure; FIG. 3 is a diagram showing an ammonia treatment system according to a third embodiment of the present disclosure; FIG. 4 is a diagram showing an ammonia treatment system according to a fourth embodiment of the present disclosure; FIG. 5 is a diagram showing an ammonia treatment system according to a fifth embodiment of the present disclosure; and FIG. 6 is a diagram showing an ammonia treatment system according to a sixth embodiment of the present disclosure. BEST MODE FOR CARRYING OUT THE INVENTION

[0028] The objects, particular advantages, and novel features of the present disclosure will become more apparent from the following detailed description and preferred embodiments associated with the accompanying drawings. In assigning reference numerals to components in each drawing herein, it should be noted that, where possible, the same numerals are given as far as identical components are concerned even if they are shown in different drawings. Further, in describing the present disclosure, if specific descriptions of related known technologies are deemed to unnecessarily obscure the gist of the present disclosure, the detailed descriptions will be omitted.

[0029] In the following, when a part is said to "include" a component, this does not mean that it excludes other components but that it may rather further include other components, unless otherwise specified.

[0030] In the following, "ammonia gas" or "ammonia fuel" may refer to a substance containing ammonia, "ammonia gas" and "ammonia fuel" may be used interchangeably, and it should be noted that ammonia gas is not necessarily limited to the gas phase due to its name, but may also be in the liquid phase.

[0031] Furthermore, "ammonia, ammonia gas, gaseous ammonia, and liquid ammonia" in the following may include components other than ammonia, such as impurities such as lubricants and inert gases such as nitrogen.

[0032] Moreover, "upstream" and "downstream" in the following are determined based on the direction in which the fluid flows in the pipe, and as one example, the point where the fluid begins to flow is upstream, and the point where the fluid flows to reach is downstream.

[0033] Although not shown in the drawings of the present disclosure, pressure sensors PT, temperature sensors TT, valves, etc., may be provided in any appropriate locations without limitation, and the measured values by respective sensors may be used in a variety of ways without limitation in the operation of the components described below, as a matter of course.

[0034] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0035] FIG. 1 is a diagram showing an ammonia treatment system according to a first embodiment of the present disclosure.

[0036] Referring to FIG. 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 may be a facility that is provided in the ammonia treatment system 1 and can store ammonia, and may include a facility in any form, and the fuel storage unit 10 may be a storage facility in the form of a tank. The fuel storage unit 10 may be a facility for storing fuel, or it may be a facility for storing cargo to be delivered from a point of origin to a destination. The fuel or cargo stored in the fuel storage unit 10 may be ammonia.

[0038] Note that the "ship" herein is a concept that encompasses not only commercial ships that transport cargo or people from their point of origin to their destination, but also offshore structures that float at a fixed point in the ocean and perform particular 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 the ammonia to a temperature appropriate for supply to the demand destination 40, and can pressurize the ammonia to a pressure appropriate for supply to the demand destination 40. For instance, ammonia with a pressure of 50 to 300 bar and a temperature of 10 to 50 degrees Celsius may be supplied to the demand destination 40. The fuel supply unit 20 may be a low-flashpoint fuel supply system (LFSS).

[0040] The fuel supply unit 20 may consist 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 the purposes of pressure regulation, flow regulation, venting, and nitrogen supply, and may supplementarily include a service tank, a nitrogen supply system, a glycol system, a gas-liquid separator, a vent mast, and the like.

[0041] The fuel supply control unit 30 is located between the fuel supply unit 20 and the demand destination 40, and can effectively cut off the fuel supply to the demand destination 40 by separating the fuel supply unit 20 and the demand destination 40 when the fuel supply unit 20 malfunctions in the fuel supply line L1. The fuel supply control unit 30 may consist of valves and filters for the purposes of double shut-off and discharge, venting, pressure regulation, nitrogen supply, etc., as well as various sensors and the like. The fuel supply control unit 30 is a mechanism in which control valves that control the ammonia to be supplied to the demand destination 40 are intensively arranged, and may be a fuel valve train (FVT).

[0042] The demand destination 40 may be an ammonia propulsion engine that propels the ship by using ammonia, or an ammonia power generation engine that produces electricity to be used on the ship.

[0043] A fuel recovery line L2 connects the demand destination 40 and the recovery tank 24, and any excess ammonia remaining unburned at the demand destination 40 may be transferred to the recovery tank 24 through the fuel recovery line L2. This excess ammonia may have a pressure of 50 to 300 bar.

[0044] The recovery tank 24 may separate excess ammonia recovered from the demand destination 40 into liquid ammonia LA and gaseous ammonia GA. Since cavitation problems may occur if gaseous liquefied gas flows into the pump 22, the liquefied gas flowing along the fuel recovery line L2 undergoes gas-liquid separation while passing through the recovery tank 24, thereby cutting off the inflow of the gaseous ammonia GA into the pump 22.

[0045] The liquid ammonia LA separated by the recovery tank 24 may be recovered to the fuel recovery line L2. The fuel recovery line L2 may be provided with a return cooler 23 for cooling the liquid ammonia LA. The liquid ammonia LA may be transferred to the fuel recovery line L2 through a recovery tank line L3, which connects the recovery tank 24 and the fuel recovery line L2. As one example, if a level gauge in the recovery tank 24 measures that the liquid level in the recovery tank 24 has reached a set height, the ammonia may be returned through the recovery tank line L3. Since the liquid ammonia LA contains impurities such as lubricating oil, these impurities may also be delivered to the recovery tank line L3.

[0046] In addition, although not shown in the drawing, a line connecting the recovery tank 24 and the fuel storage unit 10 may be provided, and the ammonia may be delivered directly from the recovery tank 24 to the fuel storage unit 10 using the line.

[0047] In this way, excess ammonia remaining unburned at the demand destination 40 may be recovered, and the liquid ammonia LA in the liquid state separated by the recovery tank 24 may be supplied back to the fuel recovery line L2.

[0048] On the other hand, the gaseous ammonia GA separated by the recovery tank 24 may be delivered to a buffer tank 50 through a vent line L4. The buffer tank 50 may temporarily store the gaseous ammonia GA.

[0049] If an emergency situation occurs, such as a fuel leak, fire, or equipment malfunction, making normal ammonia fuel supply unfeasible, the ammonia fuel supply may be stopped urgently. In contrast, when ammonia fuel supply may be performed normally but is not needed, such as when the demand destination 40 is not operating, the ammonia fuel supply may be stopped normally. When the ammonia fuel supply is stopped, it is necessary to recover ammonia fuel from the fuel supply unit 20, the fuel supply control unit 30, the demand destination 40, etc.

[0050] When the ammonia fuel supply is stopped normally, some of the ammonia fuel in the fuel supply line L1 and fuel recovery line L2 is returned to the recovery tank 24, and at this time, nitrogen is blown in through a nitrogen purge line L5, and any ammonia remaining in the fuel supply line L1 and fuel recovery line L2 is purged into the recovery tank 24. The nitrogen gas and ammonia gas in the recovery tank 24 flow into the buffer tank 50 through the vent line L4. In the buffer tank 50, the ammonia contained in the discharged gas may be captured, and the ammonia, nitrogen, oil, etc., may be separated. It is connected to a vent mast (not shown) and may discharge the nitrogen gas and the like into the atmosphere.

[0051] The ammonia in the buffer tank 50 may be delivered to the demand destination 40 and incinerated in the demand destination 40 when the demand destination 40 is in operation (when the ammonia supply is in operation). Preferably, the ammonia may be mixed with the intake air supplied from an intake supply unit 60 and supplied to the demand destination 40.

[0052] The flow rate of the ammonia supplied to the demand destination 40 is preferably small compared to the intake volume (intake flow rate) of the external air supplied from the intake supply unit 60. For example, the flow rate of the ammonia supplied to the demand destination 40 is 0.01 wt% to 1.0 wt%, and preferably about 0.05 wt% to 0.5 wt% of the intake volume of the external air supplied from the intake supply unit 60. The flow rate of the ammonia supplied to the demand destination 40 is preferably adjusted so as to be less than the lower explosion limit (LEL) of ammonia (the minimum gas concentration at which ammonia can cause an explosion) when mixed with the external air.

[0053] When the ammonia fuel supply is stopped normally, the buffer tank 50 may temporarily store ammonia, and the flow rate of the ammonia discharged from the buffer tank 50 may be adjusted. That is, when the ammonia supply to the demand destination 40 is stopped normally, the buffer tank 50 may receive ammonia from the fuel supply unit 10 and temporarily store it, and adjust the amount of ammonia supply when the ammonia is supplied. The ammonia from the buffer tank 50 is supplied in a small quantity to the demand destination 40, and the small quantity of ammonia may be incinerated via the demand destination 40.

[0054] When the ammonia fuel supply is stopped normally, any ammonia remaining in the fuel supply line L1, the fuel recovery line L2, etc., may be delivered to a treatment device (not shown) and treated. The treatment device (not shown) may reduce the ammonia concentration and discharge it to the outside.

[0055] The ammonia fuel supply may be stopped urgently when an emergency situation occurs, such as a fuel leak, fire, or equipment failure. At this point, for safety reasons, the ammonia fuel is not supplied to the demand destination 40 and is not returned from the demand destination 40. That is, the valves in the fuel supply line L1 and fuel recovery line L2 may be closed. At this time, the valve in an emergency stop line L6 is opened. The ammonia discharged through the emergency stop line L6 may be treated by a knockout drum, recovery tank, scrubber, or absorption tank. The device for treating the ammonia discharged through the emergency stop line L6 is merely one example and is not limited thereto.

[0056] Some ammonia accumulated in the fuel supply line L1 and fuel recovery line L2 may be delivered to a separately provided ammonia gas post-treatment unit (not shown) and treated.

[0057] The ammonia gas post-treatment unit (not shown) can reduce the ammonia concentration. The gas treated in the ammonia gas post-treatment unit (not shown) may be discharged urgently to the outside through a vent mast (not shown). The ammonia gas post-treatment unit (not shown) may be a device that absorbs ammonia, 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., onto a contaminated gas introduced into the scrubber, allowing the contaminants to be absorbed by the absorbent and removed, and the ammonia gas may be removed by the ammonia gas post-treatment unit (not shown) and then released into the atmosphere. The scrubber may include a packing unit, water or the like may be sprayed from the upper part of the scrubber, and ammonia gas may be injected at the lower part of the scrubber, causing the water and ammonia gas to come into contact with each other in the packing unit and the ammonia gas to be absorbed by the water. The vent gas, from which the ammonia gas has been removed, may be discharged to the outside from the upper part of the scrubber, and the ammonia water collected in the lower part of the scrubber may be discharged to the outside from the lower part of the scrubber.

[0058] For example, the ammonia gas post-treatment unit may include an oxidation catalyst unit 110 that oxidizes ammonia and / or a nitrogen oxide reduction device 70 that removes pollutants from an exhaust gas.

[0059] An absorption tank is a storage facility that stores water, an absorbent, etc., at or above a certain level, and if ammonia gas is injected directly into the absorption tank, the ammonia may be absorbed by the absorbent stored in the absorption tank.

[0060] An ammonia oxidation device can oxidize ammonia using air. The ammonia oxidation device may include an ammonia oxidation catalyst, and ammonia can be removed while the ammonia and air react in the ammonia oxidation catalyst (ammonia reforming catalyst).

[0061] An ammonia absorption device may be used when a discharge amount of ammonia is large, but the treatment of the wastewater produced in the ammonia absorption process must be accompanied. The ammonia oxidation device may be used when the discharge amount of ammonia is controlled to a small amount, but no wastewater or the like is produced after ammonia oxidation. When the ammonia fuel supply is stopped urgently, the ammonia absorption device by which ammonia can be treated in large quantities in a short period of time is preferably used.

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

[0063] FIG. 2 is a diagram showing an ammonia treatment system according to a second embodiment of the present disclosure. In the following, descriptions for parts common to FIG. 1 may be omitted.

[0064] Referring to FIG. 2, an exhaust gas discharged from the demand destination 40 may be delivered to the nitrogen oxide reduction device 70 along an exhaust gas line L7. The nitrogen oxide reduction device 70 can remove nitrogen oxides (NOx) contained in the exhaust gas by reducing the nitrogen oxides. 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) due to its name, but may also remove pollutants such as sulfur oxides (SOx) and carbon dioxide (CO2).

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

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

[0067] When the demand destination 40 is in operation, the exhaust gas discharged from the demand destination 40 and the gaseous ammonia GA delivered from the buffer tank 50 may be mixed in the nitrogen oxide reduction device 70. At this time, the nitrogen oxide reduction device 70 can oxidize the ammonia by reacting the ammonia with the nitrogen oxides contained in the exhaust gas. The ammonia oxidation reaction formula is as follows, and the ammonia may undergo an oxidation reaction in the presence of a catalyst at a temperature condition of 200 °C or higher.         4NO + 4NH3 → 4N2 + 6H2O

[0068] The flow rate of the 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 the ammonia supplied to the nitrogen oxide reduction device 70 is 0.01 wt% to 1.0 wt%, and preferably about 0.05 wt% to 0.5 wt% of the flow rate of the exhaust gas.

[0069] The buffer tank 50 may temporarily store ammonia, and the flow rate of the ammonia discharged from the buffer tank 50 may be adjusted. Therefore, ammonia can be supplied in small quantities to the nitrogen oxide reduction device 70. Since ammonia can be supplied in small quantities, the ammonia treatment system 1 can treat ammonia via the nitrogen oxide reduction device 70 installed on existing ships even though it lacks the capacity for large-scale treatment.

[0070] A gas measurement device GD and a flow meter FT may be provided between the buffer tank 50 and the nitrogen oxide reduction device 70. Some of the ammonia delivered from the buffer tank 50 to the nitrogen oxide reduction device 70 is delivered to the gas measurement device GD as a sample for checking the ammonia concentration, and the ammonia concentration can be checked at the gas measurement device GD.

[0071] The ammonia discharge amount of the buffer tank 50 can be checked at the flow meter FT. At this time, since the nitrogen oxide reduction device 70 has limitation in its treatment capacity, a flow control valve FV can adjust the flow rate of the ammonia delivered from the buffer tank 50 to the nitrogen oxide reduction device 70 according to the ammonia discharge amount of the buffer tank 50 and the ammonia concentration. Further, 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 amount of the buffer tank 50 and the ammonia concentration. The more the ammonia discharge amount of the buffer tank 50 and the higher the ammonia concentration, the smaller the amount of reducing agent supplied to the nitrogen oxide reduction device 70 without passing through the buffer tank 50 may be.

[0072] Ammonia from the fuel storage unit 10 or a cargo tank (not shown) that stores ammonia as cargo may be supplied to the nitrogen oxide reduction device 70 as a reducing agent without passing through the buffer tank 50, but the present disclosure is not limited thereto, and a reducing agent may be supplied from a separate reducing agent supply equipment. Here, any substance used to reduce nitrogen oxides, including ammonia, may be used as the reducing agent without limitation.

[0073] Although not shown in the drawing, some of the gaseous ammonia GA discharged from the buffer tank 50 may be supplied to and combusted in the demand destination 40, whereas the rest may be supplied to and oxidized in the nitrogen oxide reduction device 70.

[0074] FIG. 3 is a diagram showing an ammonia treatment system according to a third embodiment of the present disclosure.

[0075] Referring to FIG. 3, a knockout drum 80 is provided downstream of the recovery tank 24, and the gaseous ammonia GA discharged from the recovery tank 24 may be delivered to the knockout drum 80. Although not shown in the drawing, as one example, the knockout drum 80 may be provided downstream of the buffer tank 50, the gaseous ammonia GA may be supplied from the recovery tank 24 to the buffer tank 50, and the knockout drum 80 may be supplied with the gaseous ammonia GA from the buffer tank 50.

[0076] The knockout drum 80 may receive the fuel recovered from the recovery tank 24 when the ammonia fuel supply is stopped normally, 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, the liquid ammonia LA delivered to the recovery tank line L3 may be delivered to the knockout drum 80.

[0077] Furthermore, the knockout drum 80 may receive the ammonia recovered from the fuel supply line L1 and the fuel recovery line L2 through the emergency stop line L6 when the ammonia fuel supply is stopped urgently, and filter out impurities (such as lubricating oil) contained in the ammonia.

[0078] An inert gas supply unit (not shown) may supply an inert gas, such as nitrogen gas (N2) or carbon dioxide gas (CO2), to the fuel supply line L1 and the fuel recovery line L2 through the nitrogen purge line L5. The inert gas supply unit (not shown) is a component for supplying an inert gas and may include a device for generating an inert gas or a device for storing an inert gas. The inert gas may be supplied to the fuel supply line L1 and the fuel recovery line L2, causing fuel such as ammonia remaining in the fuel supply line L1 and the fuel recovery line L2 to be discharged to the knockout drum 80 or recovery tank 24.

[0079] The knockout drum 80 can separate ammonia and lubricating oil by discharging the ammonia in the gas phase and the lubricating oil in the liquid phase. The knockout drum 80 may use a heating unit (not shown), such as tracing, in order to accelerate the vaporization of the ammonia, and the heating unit (not shown) may be one that uses a medium such as steam, seawater, or the like as a heat source, or may be a component for heating using electricity.

[0080] The knockout drum 80 may deliver the gaseous ammonia to an ammonia treatment unit 90, and the lubricating oil and liquid ammonia separated therefrom may be recovered to the recovery tank 24 along a knockout drum line L8 at the lower part.

[0081] The ammonia treatment unit 90 may include a cargo tank 91, a compressor 92, a condenser 93, and a receiver 94, and the ammonia treatment unit 90 may be a reliquefaction device provided to liquefy evaporated gas generated in the cargo storage tank or fuel storage tank of an existing ship.

[0082] The gaseous ammonia GA discharged from the knockout drum 80 may be supplied to the cargo tank 91, and then liquefied while passing through the compressor 92 and condenser 93 provided on a reliquefaction line L9 together with the evaporated gas from the cargo tank 91. The liquefied ammonia may be separated in the receiver 94, the separated liquid ammonia LA may be returned to the cargo tank 91, and at this time, the inert gas such as nitrogen supplied for purging the fuel supply line L1 and the fuel recovery line L2 may be discharged to the outside from the receiver 94.

[0083] The description has been made in FIG. 3 that the gaseous ammonia GA from the knockout drum 80 is delivered to the cargo tank 91 and the ammonia is liquefied using the reliquefaction device of the cargo tank 91; however, the gaseous ammonia GA from the knockout drum 80 may also be delivered to the fuel storage unit 10, and the ammonia may be liquefied using the reliquefaction device of the fuel storage unit 10.

[0084] FIG. 4 is a diagram showing an ammonia treatment system according to a fourth embodiment of the present disclosure.

[0085] Referring to FIG. 4, the gaseous ammonia GA separated by the recovery tank 24 may be delivered to the buffer tank 50 through the vent line L4. The buffer tank 50 may temporarily store the ammonia, and the flow rate of the ammonia discharged from the buffer tank 50 may be adjusted.

[0086] The ammonia in the buffer tank 50 may be delivered to a heater 100, and the heater 100 can heat the delivered ammonia and the external air supplied by an intake device 120. The heater 100 may be one that uses a medium such as steam, seawater, or the like as a heat source, may be a component for heating using electricity, or may be a catalytic heater or an electric heater, but is not limited thereto.

[0087] The ammonia that has passed through the heater 100 may be delivered to the oxidation catalyst unit 110. The oxidation catalyst unit 110 can oxidize the ammonia using an ammonia oxidation catalyst (AOC). The ammonia oxidation catalyst may be active at about 250 to 350 °C, and the heater 100 may heat the ammonia and external air in a temperature range in which an oxidation reaction can occur in the oxidation catalyst unit 110 (the temperature range in which the ammonia oxidation catalyst is active).

[0088] The intake device 120 is a device that draws in external air, such as a fan, and can supply external air to the heater 100 along an external air line L10. The external air may be mixed with the ammonia and supplied to the oxidation catalyst unit 110.

[0089] FIG. 5 is a diagram showing an ammonia treatment system according to a fifth embodiment of the present disclosure. In the following, descriptions for parts common to FIG. 4 will be omitted.

[0090] Referring to FIG. 5, the ammonia in the buffer tank 50 may be delivered to a heater 100, and the heater 100 can heat the delivered ammonia and the external air supplied by an intake device 120.

[0091] The intake device 120 may supply external air to the heater 100 along the external air line L10, and in this case, a heat exchanger 130 may be provided downstream of the oxidation catalyst unit 110 so that the external air supplied from the intake device 120 can exchange heat with the exhaust gas discharged from the oxidation catalyst unit 110. That is, the external air may be preheated as it passes through the heat exchanger 130 and then delivered to the heater 100.

[0092] By preheating the external air using the waste heat of the exhaust gas discharged from the oxidation catalyst unit 110, the amount of energy consumption required for heating the ammonia and external air in the heater 100 can be reduced.

[0093] In one example, the ammonia treatment system according to the present disclosure may further include an ammonia reforming catalyst unit, which is disposed within the combustion unit, produces hydrogen by reforming the ammonia, and supplies the produced hydrogen to the combustion unit. FIG. 6 is a diagram showing an ammonia treatment system according to a sixth embodiment of the present disclosure.

[0094] Referring to FIG. 6, the gaseous ammonia GA from the buffer tank 50 may be delivered to a combustion unit 140. An ammonia reforming catalyst unit 141 may be provided inside the combustion unit 140. The reforming catalyst unit 141 may include any catalyst that can be used for reforming the ammonia without limitation, and may preferably include a nickel catalyst. The reforming catalyst unit 141 may be active at about 850 to 950 °C, and the ammonia can be reformed within this temperature range.

[0095] The combustion unit 140 may be supplied with the ammonia from the buffer tank 50 and combust it. At this time, the ammonia supplied to the combustion unit 140 is mixed with nitrogen or the like supplied for purging the fuel supply line L1 and the fuel recovery line L2, and the ammonia itself has a high ignition point and thus, it is difficult to combust the ammonia. Therefore, the ammonia reforming catalyst unit 141 can produce hydrogen by thermally decomposing the ammonia and supply the hydrogen to the combustion unit 140 in order to assist in the combustion of the ammonia in the combustion unit 140. The combustion unit 140 can forcibly combust the ammonia by mixing the hydrogen with the ammonia.

[0096] The ammonia reforming catalyst unit 141 is provided with an ammonia reforming catalyst, and since the ammonia reforming catalyst is active at high temperatures, the ammonia reforming catalyst unit 141 may be disposed inside the combustion unit 140 where combustion occurs in order to maintain the ammonia reforming catalyst unit 141 at a high temperature.

[0097] The gaseous ammonia GA may be delivered as pilot fuel through a pilot fuel line L11 for spark generation or initial ignition at the start of operation of the ammonia reforming catalyst unit 141. The gaseous ammonia GA may be supplied to the ammonia reforming catalyst unit 141 from a facility where the ammonia is stored, such as the fuel storage unit 10 or the cargo tank 91, but the present disclosure is not limited thereto.

[0098] The intake device 120 may supply external air to the combustion unit 140 along the external air line L10. The external air may be mixed with the ammonia and hydrogen, and the mixed gas may be combusted in the combustion unit 140.

[0099] The combustion unit 140 may be connected to the nitrogen oxide reduction device 70 and the oxidation catalyst unit 110, and the exhaust gas may be primarily treated in the nitrogen oxide reduction device 70 and then secondarily treated in the oxidation catalyst unit 110. Specifically, the ammonia can be removed in the nitrogen oxide reduction device 70 by reacting pollutants such as nitrogen oxides and sulfur oxides with the ammonia.

[0100] Since the nitrogen oxide reduction device 70 has limitation in its treatment capacity, the flow rate of the ammonia delivered from the buffer tank 50 to the nitrogen oxide reduction device 70 may be adjusted according to the ammonia discharge amount of the buffer tank 50 and the combustion unit 140 and the ammonia concentration. Further, the amount of reducing agent supplied to the nitrogen oxide reduction device 70 without passing through the buffer tank 50 may be adjusted according to the ammonia discharge amount of the buffer tank 50 and the combustion unit 140 and the ammonia concentration. The more the ammonia discharge amount of the buffer tank 50 and the higher the ammonia concentration, the smaller the amount of reducing agent supplied to the nitrogen oxide reduction device 70 without passing through the buffer tank 50 may be.

[0101] Excess ammonia can be removed in the oxidation catalyst unit 110. The combustion unit 140 may heat the ammonia and external air in a temperature range in which an oxidation reaction can occur in the oxidation catalyst unit 110.

[0102] By preheating the external air using the waste heat of the exhaust gas discharged from the oxidation catalyst unit 110, the amount of energy consumption required for heating the ammonia and external air in the heater 100 can be reduced.

[0103] As such, the ammonia treatment system 1 according to the present disclosure can safely recover the ammonia discharged when the fuel supply is stopped normally or stopped in an emergency.

[0104] In addition, the ammonia treatment system 1 according to the present disclosure can treat ammonia in the engine, nitrogen oxide reduction device, reliquefaction device, etc., provided on existing ships, and can thus prevent additional costs being incurred in order to install an ammonia treatment facility.

[0105] Furthermore, the ammonia treatment system 1 according to the present disclosure can temporarily store ammonia in the buffer tank 50 when the fuel supply is stopped normally and adjust the flow rate of the ammonia discharged from the buffer tank 50, and can thus treat the ammonia using the engine, nitrogen oxide reduction device, and oxidation catalyst that cannot treat large quantities of ammonia in a short period of time.

[0106] Moreover, the ammonia treatment system 1 according to the present disclosure can safely treat ammonia by using the ammonia treatment unit 90 provided on existing ships, not only when the ammonia fuel supply is stopped normally but also when the ammonia fuel supply is stopped urgently and a large amount of ammonia is discharged.

[0107] In addition, the ammonia treatment system 1 according to the present disclosure is provided with the heater 100 in order to meet the temperature conditions of the oxidation catalyst unit 110, and can reduce the amount of energy consumed for heating the heater 100 by preheating the external air supplied to the heater 100 using the waste heat of the exhaust gas discharged from the oxidation catalyst unit 110.

[0108] Furthermore, the ammonia treatment system 1 according to the present disclosure can reduce the energy consumed for heating the ammonia reforming catalyst unit 141 by placing the ammonia reforming catalyst unit 141 inside the combustion unit 140 in order to meet the temperature conditions of the reforming catalyst in the ammonia reforming catalyst unit 141.

[0109] Moreover, the ammonia treatment system 1 according to the present disclosure provides the oxidation catalyst unit 110 downstream of the combustion unit 140, and thus, the oxidation catalyst unit 110 can oxidize the ammonia heated in the combustion unit 140 without additionally heating it.

[0110] The present disclosure is not limited to the embodiments described above, and can include combinations of the embodiments or combinations of at least one of the embodiments with known technology as other embodiments, as a matter of course.

[0111] The present disclosure has been described in detail through specific embodiments, which, however, are intended to describe the present disclosure in detail, the present disclosure is not limited thereto, and it will be apparent that modifications and improvements are possible within the technical idea of the present disclosure by those skilled in the art.

[0112] All simple modifications and changes of the present disclosure fall within the scope of the present disclosure, and the specific scope of protection of the present disclosure will be clear by the accompanying claims.INDUSTRIAL APPLICABILITY

[0113] The ammonia treatment system according to the present disclosure can prevent environmental pollution caused by ammonia release by safely treating the ammonia released when an ammonia-propelled ship is stopped.

Claims

1. An ammonia treatment system comprising: a fuel storage unit configured to store ammonia; a fuel supply unit configured to receive the ammonia from the fuel storage unit and supply the ammonia to a demand destination; a fuel supply control unit provided between the fuel supply unit and the demand destination and configured to cut off a supply of the ammonia; a heater configured to receive the ammonia recovered from the demand destination and heat the ammonia via an external heat source; and an ammonia gas post-treatment unit configured to post-treat the ammonia heated by the heater.

2. The ammonia treatment system of claim 1, further comprising: a buffer tank configured to temporarily store the ammonia recovered from the demand destination and received from the fuel supply unit, wherein the heater receives the ammonia from the buffer tank, and the buffer tank receives the ammonia from the fuel supply unit, temporarily stores the ammonia, and adjusts a discharge amount of the stored ammonia when the supply of the ammonia to the demand destination is stopped normally.

3. The ammonia treatment system of claim 1, further comprising: an intake device configured to supply external air to the heater.

4. The ammonia treatment system of claim 3, wherein the ammonia gas post-treatment unit comprises an oxidation catalyst unit configured to oxidize the ammonia, the ammonia treatment system further comprising: a heat exchanger configured to exchange heat between an exhaust gas from the oxidation catalyst unit and the external air supplied by the intake device.

5. An ammonia treatment system comprising: a fuel storage unit configured to store ammonia; a fuel supply unit configured to receive the ammonia from the fuel storage unit and supply the ammonia to a demand destination; a fuel supply control unit provided between the fuel supply unit and the demand destination and configured to cut off a supply of the ammonia; a combustion unit configured to receive and combust the ammonia recovered from the demand destination; and an ammonia gas post-treatment unit configured to post-treat residual ammonia after passing through the combustion unit.

6. The ammonia treatment system of claim 5, further comprising: an ammonia reforming catalyst unit disposed within the combustion unit, and configured to produce hydrogen by reforming the ammonia and supply the produced hydrogen to the combustion unit.

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

8. The ammonia treatment system of claim 5, wherein the ammonia gas post-treatment unit further comprises: a nitrogen oxide reduction device provided downstream of the combustion unit and configured to remove pollutants in an exhaust gas from the combustion unit; and an oxidation catalyst unit configured to oxidize the ammonia gas.

9. The ammonia treatment system of claim 8, further comprising: a buffer tank configured to temporarily store the ammonia recovered from the demand destination and received from the fuel supply unit, wherein the nitrogen oxide reduction device is supplied with ammonia from at least one of the fuel storage unit, the buffer tank, and a cargo tank storing ammonia cargo.

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

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

12. The ammonia treatment system of claim 5, further comprising: an intake device configured to supply external air to the combustion unit.

13. The ammonia treatment system of claim 5, further comprising: a buffer tank configured to temporarily store the ammonia recovered from the demand destination and received from the fuel supply unit, wherein the buffer tank receives the ammonia from the fuel supply unit, temporarily stores the ammonia, and adjusts a discharge amount of the stored ammonia when the supply of the ammonia to the demand destination is stopped normally.

14. The ammonia treatment system of claim 5, further comprising: a fuel supply line connecting the fuel storage unit and the demand destination and configured to supply the ammonia from the fuel storage unit to the demand destination; and a fuel recovery line connecting the fuel storage unit and a recovery tank and configured to recover the ammonia from the demand destination to the recovery tank.

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