Ammonia recovery and discharge system and control method thereof

Abstract

This invention relates to an ammonia recovery and discharge system and a method for controlling the same. [Solution] The ammonia recovery and discharge system of the present invention, in a ship using ammonia fuel, comprises an ammonia tank, an engine, a fuel supply unit, a fuel recovery unit, an air supply line, an air discharge line, and a working fluid circulation unit, and is provided in the working fluid circulation unit and includes an ejector that supplies high-pressure working fluid to circulate air or ammonia to the working fluid circulation unit.

Description

【Technical Field】 【0001】 The present invention relates to an ammonia recovery and discharge system and a control method thereof. More specifically, in a ship using ammonia fuel, the air circulation of ammonia is safely performed through a double pipe, and when the ammonia engine stops, the ammonia gas in the pipe is dissolved in fresh water to primarily prevent ammonia from being released into the atmosphere, and the present invention relates to an ammonia recovery and discharge system and a control method thereof that can separate ammonia from ammonia water and reuse it. 【Background Art】 【0002】 In recent years, the use of engines using environmentally friendly fuel oils has been increasing. Ammonia is easier to store than LNG, and although its specific energy and energy density are slightly lower than those of conventional HFO, it is attracting attention in the carbon dioxide reduction policy for 2050 because it has zero carbon dioxide. 【0003】 Ammonia can be used in LPG-fueled engines with only minor modifications to the fuel supply system. As the future carbon dioxide reduction policy is strengthened, it is expected that attention to ammonia as an alternative to fuel oil will increase, and technology for using ammonia as fuel is urgently needed. 【0004】 Ammonia can be stored at a temperature of 50°C at 20 bar and 25.7°C at 10 bar. Therefore, it can be safely stored in the compression tank of a ship. The ammonia fuel stored in the compression tank needs to be supplied to the engine at a pressure of about 83 bar by the ammonia fuel supply system to maintain a liquid state, and is injected from the nozzle at an oil pressure of 600 - 700 bar in the engine to operate the engine. 【0005】 When supplying ammonia fuel, if the engine is stopped, a trip occurs, or if ammonia gasifies due to a rise in temperature, the fuel supply must be shut off and the ammonia in the ammonia fuel supply system must be discharged to the outside. 【0006】 Furthermore, the ammonia piping that supplies ammonia through safety areas such as the engine room is constructed as a double pipe, requiring air purging 30 times per hour between the inner and outer pipes. If ammonia leaks from the inner pipe, the ammonia operation of the engine must be stopped, and the ammonia must be quickly discharged to the outside. [Overview of the Initiative] [Problems that the invention aims to solve] 【0007】 To solve the above problems, the present invention aims to provide an ammonia recovery and discharge system and a control method thereof. 【0008】 Furthermore, the objective is to provide an ammonia recovery and discharge system and method that utilizes water (freshwater) when operating the ammonia recovery and discharge system, thereby significantly reducing the risk in the event of leakage. 【0009】 More specifically, the present invention aims to provide an ammonia recovery and discharge system and method for safely circulating ammonia gas through a double-walled pipe in a vessel using ammonia fuel. 【0010】 Furthermore, the present invention aims to temporarily prevent the release of ammonia gas into the atmosphere by dissolving the ammonia gas in the pipe into fresh water when an ammonia-fueled engine stops. 【0011】 Furthermore, the present invention aims to separate and reuse ammonia from ammonia water produced by dissolving ammonia gas in freshwater, or to safely discharge it overboard. 【0012】 The technical problems of the present invention are not limited to those described above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the following description. [Means for solving the problem] 【0013】 To achieve the above objectives, one embodiment of the present invention provides an ammonia recovery and discharge system for a ship using ammonia fuel, comprising: an ammonia tank for storing liquid ammonia; an engine located in the engine room and operated by being supplied with fuel from the ammonia tank; a fuel supply unit provided with a fuel supply line for supplying ammonia fuel from the ammonia tank to the engine; a fuel recovery unit provided with a fuel return line for recovering ammonia not consumed by the engine back into the ammonia tank; an air supply line for supplying air to the fuel supply line and the fuel return line; an air discharge line for discharging the air supplied to the fuel supply line and the fuel return line; and a working fluid circulation unit through which a working fluid circulates to discharge air or ammonia from the fuel supply line and the fuel return line; and an ejector provided in the working fluid circulation unit for supplying high-pressure working fluid to circulate air or ammonia back into the working fluid circulation unit. 【0014】 Preferably, the working fluid circulation unit comprises a working fluid storage tank for storing and recovering working fluid supplied to the ejector; a first vent line for discharging air supplied to the working fluid storage tank overboard; a chiller for cooling the working fluid flowing into the working fluid storage tank; and an ammonia recovery unit for recovering ammonia flowing into the working fluid circulation unit, wherein the working fluid storage tank is connected to the ejector via a working fluid supply line, and the ejector is connected to the working fluid storage tank via a working fluid recirculation line. 【0015】 Preferably, a portion of the fuel supply line and fuel return line are provided in the engine compartment, and the fuel supply line and fuel return line in the engine compartment are made of double pipes, and the annular space formed between the inner and outer pipes of the double pipe is connected to the air supply line and the air discharge line, the air discharge line is connected to the ejector, and the system also includes a first ammonia sensor for measuring ammonia concentration, a pressure sensor for measuring air flow rate, and a circulation shut-off valve for controlling air circulation when ammonia operation is interrupted, and the air supplied to the annular space via the air supply line is supplied to the ejector via the air discharge line, and the air supplied to the ejector flows into the working fluid storage tank via the working fluid recirculation line. 【0016】 Preferably, the first vent line is provided from the upper end of one end of the working fluid storage tank, a second ammonia sensor is provided in the first vent line, and the air discharged overboard via the air discharge line passes through the buffer plate. 【0017】 Preferably, the working fluid storage tank is connected to the ammonia recovery unit via an ammonia water supply line. When ammonia is detected by the first ammonia sensor, the supply of ammonia fuel is interrupted, and the ammonia that flows in through the air discharge line is supplied to the packing material unit where it dissolves in the working fluid. The ammonia dissolved in the working fluid then passes through a buffer plate and is supplied to the ammonia recovery unit from the bottom of the working fluid storage tank. 【0018】 Preferably, a liquid fuel supply system section is provided in the fuel supply line, a fuel valve train region is provided in the fuel supply line and fuel return line downstream of the fuel supply system section, the liquid fuel supply system section is connected to the ejector via a first ammonia recovery line, and the fuel return line is connected to the ejector via a second ammonia recovery line. 【0019】 Preferably, a first double shut-off valve is provided in the fuel supply line of the fuel valve train region, a second double shut-off valve is provided in the fuel return line of the fuel valve train region, the first double shut-off valve is connected to the ejector via a third ammonia recovery and discharge line, and the second double shut-off valve is connected to the ejector via a fourth ammonia recovery and discharge line. 【0020】 Preferably, the system further includes an ammonia dilution section for diluting ammonia that has flowed into the working fluid storage tank; the ammonia dilution section is provided between the working fluid storage tank and the first vent line, and the ammonia dilution section includes an ammonia dilution chamber into which ammonia is supplied and diluted; and a dilution fan for diluting the ammonia in the ammonia dilution chamber. 【0021】 Preferably, the ammonia recovery unit comprises: an ammonia water tank that flows into a working fluid storage tank to recover ammonia dissolved in the working fluid, and to which ammonia water is supplied from the working fluid storage tank and evaporated to separate ammonia from the working fluid; a gas-liquid separator provided above the ammonia water tank to separate the evaporated working fluid from the ammonia; an ammonia compressor that compresses the ammonia separated by the gas-liquid separator; and a combustion unit to which the compressed ammonia is supplied and burned for reuse as fuel. 【0022】 Preferably, the ammonia recovery unit further includes a cooler that cools the ammonia by operating a chiller, and when the ammonia compressed in the ammonia compressor is in a gaseous state, it is supplied to the cooler and liquefied, and the liquefied ammonia is supplied to the combustion unit. 【0023】 Preferably, the working fluid storage tank is connected to an ammonia water tank via an ammonia water supply line, the ammonia water supply line is branched from the working fluid supply line and is equipped with an ammonia water discharge selection valve, the ammonia water tank is connected to the ejector via a working fluid recovery line, and the working fluid recovery line is equipped with a working fluid recovery valve. 【0024】 In addition, to achieve the above object, another embodiment of the present invention includes a fuel supply step of supplying ammonia fuel from an ammonia tank to an engine by a fuel supply unit including a fuel supply line; During the execution of the fuel supply step, an operating fluid circulation step of supplying and circulating high-pressure operating fluid to an ejector provided in the operating fluid circulation unit; is executed, and when the fuel supply step is interrupted, an ammonia recovery step of recovering ammonia by an ammonia recovery unit; is executed, and a control method for an ammonia recovery and discharge system is provided. 【0025】 Preferably, the operating fluid circulation step includes an air circulation step of supplying air to the fuel supply line and the fuel return line and discharging the supplied air; The air circulation step includes an air supply step of supplying air to the annular space between the double-pipe fuel supply line and the fuel return line; and an air discharge step of supplying the air flowing into the annular space to the ejector, the air supplied to the ejector flowing into the operating fluid storage tank through the operating fluid recirculation line, and the air flowing into the operating fluid storage tank passing through the buffer plate and then being discharged to the outside from the upper part. 【0026】 Preferably, it further includes an ammonia leakage detection step, and the ammonia leakage detection step includes a first ammonia leakage detection step of detecting ammonia leakage from the inner pipe to the outer pipe in the double pipe; and a second ammonia leakage detection step of detecting ammonia leakage from the operating fluid storage tank. 【0027】 Preferably, in the first ammonia leakage detection step, when ammonia leakage is detected by a first ammonia sensor, the operation of the engine and the supply of ammonia fuel are interrupted and the ammonia recovery step is executed. The ammonia recovery step includes a first ammonia recovery step of recovering ammonia fuel existing in the fuel supply line and the fuel return line by the ammonia recovery unit; and a second ammonia recovery step of supplying nitrogen to the fuel supply line to recover ammonia remaining in the fuel supply line and the fuel return line. 【0028】 Preferably, the ammonia recovered by the ejector in the first ammonia recovery step flows into the working fluid storage tank, the ammonia flowing into the working fluid storage tank is supplied to the filler section, the ammonia supplied to the filler section is dissolved in the working fluid, and the ammonia (aqueous ammonia) dissolved in the working fluid passes through the buffer plate and is supplied and recovered from the lower part of the working fluid storage tank to the ammonia recovery section. 【0029】 Preferably, the aqueous ammonia supplied to the ammonia recovery section is separated into the working fluid and ammonia. The separation of the aqueous ammonia includes the steps of supplying the aqueous ammonia to an aqueous ammonia tank; heating the aqueous ammonia tank to the evaporation temperature of ammonia; supplying the ammonia evaporated from the aqueous ammonia tank to a gas-liquid separator to separate it into ammonia and the working fluid; supplying the separated ammonia to a compressor to compress it; and supplying the compressed ammonia to a combustion section to burn it and reuse it as fuel. 【0030】 Preferably, when the second ammonia leakage detection step detects ammonia leakage with the second ammonia sensor, it operates the chiller so that the concentration of ammonia measured by the second ammonia sensor is lower than 20 ppm, and includes a cooling step of cooling the working fluid (aqueous ammonia) in which ammonia is dissolved in the working fluid storage tank. If the ammonia concentration is 20 ppm or less after the cooling step, it is controlled so that the cooling temperature of the chiller gradually rises, and the working fluid in which ammonia is dissolved in the working fluid storage tank is supplied to the ammonia recovery section. 【0031】 Preferably, if the ammonia concentration detected by the second ammonia sensor after the cooling step is 20 ppm or higher, an ammonia dilution step is performed in which the dilution fan is operated to dilute the ammonia in the ammonia dilution chamber. If the ammonia concentration is 20 ppm or lower after the cooling step or the ammonia dilution step, the cooling temperature of the chiller is controlled to gradually increase, and the working fluid in which ammonia is dissolved in the working fluid storage tank is supplied to the ammonia recovery unit. [Effects of the Invention] 【0032】 This invention provides an ammonia recovery and discharge system and a control method. 【0033】 Furthermore, because the ammonia recovery and discharge system uses water (clean water) to operate, the risk of leakage is significantly reduced. 【0034】 It also prevents ammonia from being released into the atmosphere. 【0035】 Furthermore, ammonia can be dissolved in water (freshwater) and gradually discharged in accordance with emission regulations. 【0036】 Furthermore, to prevent ammonia from being released into the atmosphere, ammonia can be separated from ammonia water produced by dissolving ammonia gas, allowing for the reuse of ammonia and safe discharge overboard. 【0037】 The effects of the present invention are not limited to those described above, and any other effects not mentioned can be clearly understood by those skilled in the art from the following description. [Brief explanation of the drawing] 【0038】 [Figure 1] A diagram showing an ammonia recovery and discharge system according to one embodiment of the present invention. 【0039】 [Figure 2] A diagram showing an ammonia recovery and discharge system according to another embodiment of the present invention. Means for carrying out the invention 【0040】 The objectives, technical configuration, and details of the operation and effects of the present invention can be clearly understood from the drawings and detailed description attached to this specification. 【0041】 The terminology used in this specification is used solely to describe specific embodiments and is not intended to limit the invention. For example, in this specification, "including" a component means, unless otherwise stated, that other components may be included, rather than excluding them. Furthermore, "connecting" or "linking" a component to another component should be understood to mean that it may be directly connected to or linked to the other component, or that other components may be present between them. 【0042】 The following description will detail preferred embodiments of the present invention with reference to the attached drawings. The embodiments described below are provided to facilitate understanding of the technical concept of the present invention by those skilled in the art, but should not be interpreted as limiting the invention. It is natural that embodiments of the present invention can be applied in various ways by those skilled in the art. 【0043】 Ammonia is an environmentally friendly fuel oil with zero carbon dioxide emissions, making it a focus of carbon dioxide reduction policies for 2050. It can be used directly in LPG-fueled engines and can be immediately implemented with only minor modifications to the fuel supply system. As carbon dioxide reduction policies are strengthened in the future, attention to ammonia as a fuel oil alternative is expected to increase, making the technology for using ammonia as fuel an urgent necessity. 【0044】 Ammonia can be stored at temperatures down to 50°C at 20 bar and down to 25.7°C at 10 bar. Therefore, it can be safely stored in pressurized tanks on ships. The ammonia fuel stored in the pressurized tank needs to be supplied to the engine at a pressure of approximately 83 bar by the ammonia fuel supply system to maintain its liquid state, and is then injected from nozzles at a hydraulic pressure of 600-700 bar to operate the engine. 【0045】 When supplying ammonia fuel, if the engine is stopped, a trip occurs, or if ammonia gasifies due to a rise in temperature, the fuel supply must be shut off and the ammonia in the ammonia fuel supply system must be discharged to the outside. 【0046】 Furthermore, the ammonia piping that supplies ammonia through safety areas such as the engine room is constructed as a double-walled pipe, requiring air purging 30 times per hour between the inner and outer pipes. If ammonia leaks from the inner pipe, the engine's ammonia operation must be stopped, and the ammonia must be quickly discharged to the outside. 【0047】 The ammonia recovery and discharge system and control method of the present invention will be described in detail below. 【0048】 In the following, the term "ship" as used in the present invention refers to any vessel equipped with an engine that uses ammonia as fuel, and includes, for example, self-propelled vessels such as LPG carriers, LNG carriers, and liquid hydrogen carriers, as well as floating offshore structures that do not have the ability to propel themselves. 【0049】 The term "ammonia-fueled engine" includes both engines that are simultaneously supplied with other marine fuels such as LNG, LPG, and HFO, and engines that are supplied solely with ammonia. This term encompasses both ship propulsion engines and power generation engines. 【0050】 An ammonia recovery and discharge system according to one embodiment of the present invention is an ammonia recovery system, an ammonia discharge system, or an ammonia recovery and discharge system. 【0051】 Figure 1 is a diagram showing an ammonia recovery and discharge system according to one embodiment of the present invention. 【0052】 Referring to Figure 1, a ship using ammonia fuel comprises an ammonia tank 100 for storing liquid ammonia, an engine E located in the engine room and operated by being supplied with fuel from the ammonia tank 100, a fuel supply unit having a fuel supply line FSL, a fuel recovery unit having a fuel return line FRL, and a working fluid circulation unit through which working fluid is circulated to discharge air or ammonia from the fuel supply line and the fuel return line. 【0053】 The ammonia tank 100 stores liquid ammonia supplied to a ship's engine. By compressing gaseous ammonia or lowering the temperature inside the tank, ammonia can be stored in liquid form. For example, the pressure inside the ammonia tank 100 is set to approximately 18 bar to store the ammonia in liquid form. 【0054】 Engine E is located in the Engine Room (E / R) and comprises one or more engines, with the number of engines being changeable as needed. Engine E is fueled by ammonia supplied from an ammonia tank and is connected to the SCR system 600 and exhaust gas discharge line EL1 to discharge the exhaust gases generated during the operation of Engine E. 【0055】 The fuel supply unit supplies fuel gas from the ammonia tank 100 to the engine E and has a fuel supply line FSL. 【0056】 In detail, the fuel supply line FSL connects the ammonia tank 100 and the engine E, and the fuel supply line FSL is equipped with a low-pressure pump 1, a high-pressure pump 2, a temperature controller 4, and a filter 5. 【0057】 The low-pressure pump 1 supplies liquid ammonia stored in the ammonia tank 100 to the engine E, and the high-pressure pump 2 (pressurizing pump) pressurizes the ammonia transported from the low-pressure pump 1 to the pressure required by the engine and supplies it. 【0058】 The temperature controller 4 adjusts the temperature of the ammonia by heating or cooling the ammonia, which has been pressurized by the high-pressure pump 2, to the temperature required by the engine E before supplying it to the filter 5. 【0059】 The filter 5 protects engine E by filtering out foreign matter contained in the fuel before supplying pressurized ammonia, which has been temperature-controlled by the temperature controller 4, to engine E. 【0060】 A high-pressure pump 2, a temperature regulator 4, and a filter 5 constitute a liquid fuel supply system (LFSS). The ammonia fuel pressurized by the high-pressure pump 2 is at a pressure of 83 bar, and the ammonia fuel is continuously cooled or heated. 【0061】 The fuel recovery unit recovers ammonia that was supplied to engine E but not consumed, and has a fuel return line (FRL). 【0062】 In detail, the fuel return line FRL connects engine E to ammonia tank 100, and ammonia fuel is recovered into ammonia tank 100 via the fuel return line FRL. 【0063】 Here, a portion of the fuel supply line FSL and the fuel return line FRL are installed in the engine compartment. To prevent leakage of liquid ammonia, the fuel supply line FSL and fuel return line FRL installed in the engine compartment are constructed as double-walled pipes, each consisting of inner pipes IP1 and IP2 through which ammonia flows, and outer pipes OP1 and OP2 that surround the outside of each inner pipe. 【0064】 The inner pipes IP1 and IP2 are sealed by the outer pipes OP1 and OP2 or ducts, preventing ammonia gas from leaking into the engine compartment even if it leaks from the inner pipes IP1 and IP2. 【0065】 Furthermore, the space formed between the inner tubes IP1 and IP2 and the outer tubes OP1 and OP2 of the double-walled pipe is an annular space, into which air is continuously injected by an exhaust ventilator, and the injected air is discharged into the atmosphere according to the level of ammonia concentration in the air. 【0066】 For example, air can be injected into the annular space through a ventilation air inlet. More specifically, air is injected into the annular space from the ventilation air inlet, which is connected via the air supply line AL1 to the end of the fuel return line or the double-walled fuel supply line. 【0067】 Air injected through the ventilation air intake is discharged to the outside via the working fluid circulation section 300. The starting point of the double pipe of the fuel supply line or fuel return line is connected to the working fluid circulation section via the air discharge line AL2, and the air that has circulated in the annular space is discharged to the outside via the air discharge line AL2. 【0068】 For example, in a structure where the end of the double-walled fuel return line is connected to the ventilation air intake via the air supply line AL1, the start of the double-walled fuel supply line is connected to the working fluid circulation section via the air discharge line AL2. Similarly, in a structure where the end of the double-walled fuel supply line is connected to the ventilation air intake via the air supply line AL1, the end of the double-walled fuel return line is connected to the working fluid circulation section via the air discharge line AL2. In other words, by changing the connection position between the air supply line AL1 and the air discharge line AL2, air circulation can be achieved by connecting the air supply line AL1 to the air discharge line AL2. 【0069】 The working fluid circulation unit 300 comprises an ejector 200 and a working fluid storage tank 310 for storing and recovering the working fluid supplied to the ejector 200. The working fluid storage tank 310 is connected to the ejector 200 via a working fluid supply line and a working fluid circulation line, and the ejector 200 is connected to the starting point of a double pipe of the fuel supply line via an air discharge line AL2. 【0070】 Furthermore, an ejector pump 210 is provided in the working fluid supply line. By operating the ejector pump, pressure is generated in the working fluid supply line, and the flow velocity is increased by supplying high-pressure working fluid to the ejector. As the flow velocity increases, low pressure is generated to create a vacuum, and air injected into the annular space via the air supply line AL1 is drawn in and circulated. At this time, two or more ejector pumps 210 are provided, and if one fails, a backup pump (STANDBY PUMP) is operated to ensure safety. 【0071】 The working fluid supply line comprises a first working fluid supply line equipped with an air cooler 240 and a second working fluid supply line not equipped with an air cooler. An air cooler selection valve 250 is provided upstream of the ejector pump 210 to selectively supply the working fluid to either the first working fluid supply line or the second working fluid supply line. 【0072】 For example, when the ejector pump 210 is in operation, heat is generated in the ejector pump 210, and working fluid is supplied via the first working fluid supply line to dissipate the heat generated in the ejector pump 210. 【0073】 When working fluid is supplied via the first working fluid supply line, the working fluid is cooled by the air cooler 240 and supplied to the ejector pump 210, and the temperature of the ejector pump decreases due to the coldness of the working fluid. 【0074】 Here, the air cooler 240 may be of the air tube type, and by supplying cooled working fluid, it prevents the generation of air bubbles on the ejector pump 210 side. 【0075】 Furthermore, the air discharge line AL2 is equipped with a flow sensor or pressure sensor 230, which is used to measure whether the airflow is smooth in the annular space of the double pipe. 【0076】 Inside the working fluid storage tank 310, a packing material section 320 and a buffer plate 330 are provided. Preferably, the packing material section 320 is connected to a working fluid recirculation line, and the working fluid that has passed through the ejector 200 is supplied to the packing material section 320. 【0077】 Preferably, the air that has passed through the packing material section 320 and flowed into the working fluid storage tank 310 passes through the buffer plate 330 and is then discharged to the outside through the first vent line L1. 【0078】 Preferably, the first vent line L1 extends from the upper end of one end of the working fluid storage tank, and a second ammonia sensor is provided on the first vent line L1. 【0079】 In detail, the ammonia recovery system includes an ammonia dilution section between the top of the working fluid storage tank 310 and the first vent line L1 for diluting ammonia. The ammonia dilution section comprises an ammonia dilution chamber 370 that receives and dilutes ammonia, and a dilution fan 380 that dilutes the ammonia in the ammonia dilution chamber. 【0080】 Here, the first vent line L1 is located at the top of the ammonia dilution chamber 370, and ammonia is not discharged, only air is discharged to the outside. 【0081】 Preferably, the working fluid storage tank 310 is equipped with a level sensor 340 at the bottom of the working fluid storage tank 310 to prepare for evaporation of the working fluid, and a working fluid replenishment valve 350 is provided to automatically inject working fluid to maintain the working fluid at a constant level according to the measurement value of the level sensor 340. Preferably, the working fluid injected by the working fluid replenishment valve 350 is fresh water. 【0082】 The air discharge line AL2 is equipped with a first ammonia sensor 220 and a circulation shut-off valve 260. When the first ammonia sensor 220 detects ammonia, it is determined that ammonia has leaked from the inner pipes IP1 and IP2 of the double pipe, and the operation of engine E is stopped, interrupting the supply of ammonia fuel to engine E. 【0083】 Preferably, after confirming that the ammonia concentration at the first ammonia sensor 220 becomes zero, the circulation shut-off valve 260 is shut off. 【0084】 In other words, it is preferable to simultaneously recover ammonia water from the system and circulate air through a double pipe (double-pipe ventilation), and then close the circulation shut-off valve 260 when the ammonia concentration at the first ammonia sensor 220 becomes zero. 【0085】 Preferably, the ammonia fuel present in the system is supplied to the ammonia recovery unit 500 and discharged. 【0086】 In detail, the ejector 200 in the ammonia recovery and discharge system is connected to the fuel supply section via a first ammonia recovery vent line VL1 and to the fuel recovery section via a second ammonia recovery vent line VL2. 【0087】 Preferably, the ejector 200 is connected to the liquid fuel supply system (LFSS) of the fuel supply unit via a first ammonia recovery vent line VL1, and to the fuel return line FRL via a second ammonia recovery vent line VL2, with a first vent valve VV1 provided in the first ammonia recovery vent line VL1 and a second vent valve VV2 provided in the second ammonia recovery vent line VL2. 【0088】 Preferably, a fuel valve train (FVT) region is provided in the fuel supply line FSL and fuel return line FRL downstream of the fuel supply system, and double shut-off valves are provided in the fuel supply line FSL and fuel return line FRL within the fuel valve train region. 【0089】 A double block and bleed valve is installed in the fuel piping to efficiently shut off the fuel supply. It effectively isolates the fuel supply system from the engine by branching the vent pipe between the fuel supply system and the engine. 【0090】 Preferably, a first double shut-off valve DV1 is provided in the fuel supply line FSL of the fuel valve train FVT region, the first double shut-off valve DV1 is connected to the ejector 200 via a third ammonia recovery vent line VL3, and a second double shut-off valve DV2 is connected to the ejector 200 via a fourth ammonia recovery vent line VL4. 【0091】 In other words, it is preferable that the ammonia fuel in each region of the system is supplied to the ejector 200 via the first ammonia recovery vent line VL1, the second ammonia recovery vent line VL2, the third ammonia recovery vent line VL3, and the fourth ammonia recovery vent line VL4, and that the ammonia supplied to the ejector 200 flows into the working fluid storage tank 310 via the working fluid recirculation line together with the working fluid. 【0092】 Preferably, a working fluid containing ammonia is supplied to the packing material section 320 in the working fluid storage tank 310. The ammonia supplied to the packing material section 320 dissolves in the working fluid, and the ammonia dissolved in the working fluid (ammonia water) passes through the buffer plate 330 and is then supplied to the ammonia recovery section 500 via an ammonia water supply line formed at the bottom. 【0093】 The filler section 320 is filled with an ammonia-resistant material in order to maximize the reaction area of ​​ammonia and increase the reaction rate and efficiency with the working fluid (fresh water) so that dissolution proceeds smoothly. 【0094】 Preferably, ammonia that leaks from the inner tubes IP1 and IP2 of the double tube and flows into the ejector is recovered in the ammonia recovery unit 500 along with the recovered ammonia. 【0095】 Furthermore, the ammonia recovery and discharge system may be further equipped with a nitrogen supply unit to supply nitrogen in order to completely remove ammonia from the system. 【0096】 In detail, nitrogen is supplied to the system via a nitrogen supply line NL, which is preferably connected downstream of the first double shut-off valve DV1. Preferably, the supplied nitrogen passes through the inner tubes IP1 and IP2 of the double tube and is then supplied to the ejector via the second ammonia recovery vent line VL2. 【0097】 The ammonia recovery and discharge system according to the present invention may include a control unit (not shown). Preferably, the control unit controls the operation of the ammonia recovery and discharge system and controls the fuel gas flow and engine operating mode using temperature and ammonia concentration information measured by detectors and sensors in the system. 【0098】 Figure 2 is a configuration diagram showing an ammonia recovery and discharge system of another embodiment of the present invention. Except for the configurations described below, the configuration of the ammonia recovery and discharge system described above is applied as is with reference to Figure 1. 【0099】 The configuration of the ammonia recovery and discharge system, as explained with reference to Figure 1, will not be described here. 【0100】 Referring to Figure 2, the ammonia recovery section is for recovering ammonia (ammonia water) that flows into the working fluid storage tank 310 and is dissolved in the working fluid. It is equipped with an ammonia water tank 700, a gas-water separator 740, an ammonia compressor 750, and a combustion section 800. 【0101】 Preferably, an ammonia water tank 700 is connected to a working fluid storage tank 310 via an ammonia water supply line, the ammonia water supply line is branched from the working fluid supply line, and an ammonia water discharge valve (not shown) is provided at the branching point of the working fluid supply line. 【0102】 The ammonia water tank 700 separates the ammonia water supplied from the working fluid storage tank 310 into ammonia and working fluid, and is equipped with an electric heater 710 and a temperature sensor 720. 【0103】 Ammonia water is separated by utilizing the fact that ammonia and the working fluid have different evaporation temperatures. The ammonia water is heated to a predetermined temperature using an electric heater 710, and separated into the working fluid and ammonia evaporation gas (ammonia in gaseous state). 【0104】 Here, the ammonia is heated to a temperature where it evaporates but the working fluid does not, although a small amount of working fluid may evaporate at the same time. Therefore, it is preferable to install a working fluid collector (freshwater collector, water catcher) in the ammonia water tank 700 to separate the small amount of working fluid from the ammonia evaporation gas. 【0105】 Preferably, a small amount of working fluid that has not been separated in the working fluid collector is supplied to the gas-liquid separator 740 together with the ammonia evaporated gas, where the ammonia evaporated gas and the working fluid are secondarily separated. 【0106】 Preferably, the separated working fluid is supplied to the ejector 200 via the working fluid recovery line WRL, and the working fluid supplied to the ejector 200 is recovered in the working fluid storage tank 310. 【0107】 Preferably, the ammonia compressor 750 compresses the ammonia evaporated gas separated in the gas-liquid separator 740 to a pressure of 8 bar to 10 bar. 【0108】 The ammonia compressed in the compressor 750 is either supplied to the cooler 760 where it is liquefied, or supplied to the combustion section 800. 【0109】 Preferably, when compressed ammonia is supplied to the cooler 760, the chiller 400, which is configured to cool the ammonia, is operated to cool and liquefy the compressed ammonia. In this case, it is preferable that the cooler 760 uses the chiller 400 to lower the temperature of the ammonia to about 10°C and liquefy it. 【0110】 Preferably, a boiler or incinerator is provided in which the combustion section 800 is configured to burn ammonia supplied from an ammonia compressor 750 or a cooler 760 and reuse it as fuel. 【0111】 Depending on the type of boiler installed in the combustion section 800, liquefied ammonia or gaseous ammonia is supplied to the combustion section fluidly. Preferably, when supplying liquefied ammonia to the combustion section, compressed ammonia is supplied to the cooler 760 to be liquefied before being supplied to the combustion section 800, and when supplying gaseous ammonia, it is supplied to the combustion section 800 without passing through the cooler 760. 【0112】 【0113】 The following describes a control method for an ammonia recovery and discharge system according to one embodiment of the present invention, with reference to the ammonia recovery and discharge system according to one embodiment of the present invention described above. 【0114】 The control method for the ammonia recovery and discharge system includes a fuel supply step in which ammonia fuel is supplied from an ammonia tank 100 to the engine E by a fuel supply unit provided with a fuel supply line FSL, and during the execution of the fuel supply step, an operating fluid circulation step is performed in which high-pressure operating fluid is supplied to and circulated to an ejector 200 provided in an operating fluid circulation unit 300, and when the fuel supply step is interrupted, an ammonia recovery step is performed in which ammonia is recovered in an ammonia recovery unit. 【0115】 Preferably, in the fuel supply step, the low-pressure pump 1 is operated to supply liquid ammonia stored in the ammonia tank 100 to the engine E, and the high-pressure pump 2 is used to pressurize the ammonia transported by the low-pressure pump 1 to the pressure required by the engine and supply it. 【0116】 A portion of the ammonia pressurized by the high-pressure pump 2 is recovered in the ammonia storage tank 100 and can be resupplied using the high-pressure pump 2 again. 【0117】 Furthermore, the ammonia fuel pressurized by the high-pressure pump 2 is supplied to the temperature controller 4, where it is heated or cooled to the temperature required by the engine E. The pressurized ammonia with the adjusted temperature is then supplied to the filter 5 to remove foreign matter. When liquid ammonia is used, a vaporizer is not required. The liquid ammonia is pressurized to approximately 83 bar by the pump, adjusted to the temperature range required by the engine E (25°C to 55°C) by the heat exchanger, and then supplied to the engine. 【0118】 The fuel supply step is performed simultaneously with the fuel recovery step, and while the fuel supply step is being performed, any ammonia not consumed by engine E can be recovered again into the ammonia tank 100 via the fuel return line FRL. 【0119】 The working fluid circulation step is performed concurrently with the fuel supply step and includes a working fluid supply step of supplying working fluid from the working fluid storage tank 310 to the ejector 200, and a working fluid recirculation step of recirculating the working fluid that has passed through the ejector 200 back to the working fluid storage tank 310. 【0120】 The working fluid circulation step includes an air circulation step of supplying air to the fuel supply line and the fuel return line and discharging the supplied air. The air circulation step includes an air supply step of supplying air to the annular space of the double-pipe fuel supply line and fuel return line; and an air discharge step of supplying the air that has flowed into the annular space to the ejector 200, the air supplied to the ejector 200 flowing into the working fluid storage tank 310 via the working fluid recirculation line, and the air that has flowed into the working fluid storage tank 310 passing through a buffer plate and being discharged to the outside from the top. 【0121】 In detail, the air discharge step involves supplying air to the annular space and then discharging this supplied air overboard. The air is injected into the annular space via an air supply line AL1 connected to the end of a double pipe of the fuel return line, and the air injected into the annular space is supplied to the working fluid circulation unit 300 via an air discharge line AL2. 【0122】 Here, a working fluid is circulated to expel the air injected into the annular space overboard. Preferably, an ejector pump 210 is operated to circulate the working fluid. 【0123】 In detail, when the ejector pump 210 is operated, pressure is generated in the working fluid supply line, the working fluid becomes high pressure, and the flow velocity increases by supplying the high-pressure working fluid to the ejector 200. As the flow velocity increases, low pressure is generated and a vacuum is created. When a vacuum is created, the air supplied to the annular space flows into the ejector 200 via the air discharge line AL2. 【0124】 The air circulation step is always necessary when the engine is running on ammonia. Ammonia operation is initiated only when flow is detected by the pressure sensor or flow sensor 230. 【0125】 The system determines whether a flow that creates a vacuum state is formed under a predetermined pressure. If an excessive or weak vacuum state occurs, it is determined that the annular space of the double-walled pipe is "blocked" or that "the flow rate is insufficient," and the ammonia operation is stopped. 【0126】 For example, a flow sensor or pressure sensor 230 measures the vacuum level to determine the flow. If the vacuum level is above the design value, it is determined that the pressure drop is increasing due to foreign matter in the piping. If it is below the design value, it is determined that the flow is low and the pressure drop is decreasing, and it is determined that a problem has occurred, so the ammonia operation is stopped. 【0127】 A control method for an ammonia recovery and discharge system may further include an ammonia leak detection step. Preferably, the ammonia leak detection step is performed in real time while supplying ammonia fuel and operating the engine. 【0128】 In detail, the ammonia leak detection step includes a first ammonia leak detection step for detecting ammonia leaks from the inner tubes IP1 and IP2 of the double-walled pipe, and a second ammonia leak detection step for detecting ammonia leaks from the working fluid storage tank. 【0129】 The first ammonia leak detection step detects whether there is a gas leak from the inner pipes IP1 and IP2 of the double-walled pipe to the outer pipes OP1 and OP2. If ammonia is detected by the first ammonia sensor 220, it is determined that "ammonia gas has leaked." 【0130】 If it is determined that "ammonia gas has leaked," the engine operation and the supply of ammonia fuel are interrupted, and then the first double shut-off valve DV1 and the second double shut-off valve DV2 are shut off to perform the ammonia recovery step. The ammonia recovery step includes: a first ammonia recovery step in which ammonia fuel present in the fuel supply line FSL and fuel return line FRL is recovered in the ammonia recovery section; and a second ammonia recovery step in which nitrogen is supplied to the fuel supply line FSL to recover any remaining ammonia in the fuel supply line FSL and fuel return line FRL. 【0131】 In detail, the first ammonia recovery step involves recovering and discharging ammonia from the liquid fuel supply system LFSS and the fuel return line FRL using the ammonia recovery unit 500. Preferably, ammonia generated in the liquid fuel supply system LFSS is recovered to the ammonia recovery unit 500 via the first ammonia recovery vent line VL1, and ammonia from the fuel return line FRL is recovered to the ammonia recovery unit 500 via the second ammonia recovery vent line VL2. 【0132】 Preferably, when the first double shut-off valve DV1 and the second double shut-off valve DV2 are shut off, ammonia that has not been recovered in the fuel supply line FSL and the fuel return line FRL is recovered in the ammonia recovery section via the third ammonia recovery vent line VL3 and the fourth ammonia recovery vent line VL4. 【0133】 Specifically, the ammonia recovered through the first ammonia recovery vent line VL1, the second ammonia recovery vent line VL2, the third ammonia recovery vent line VL3, and the fourth ammonia recovery vent line VL4 is supplied to the ejector 200, mixed with the working fluid, and then supplied to the packing material section 320 together with the working fluid. 【0134】 Preferably, ammonia supplied to the packing material section 320 is dissolved in the working fluid (fresh water) by the packing material section 320, and the ammonia dissolved in the working fluid (ammonia water) passes through the buffer plate 330 and is then recovered from the bottom of the working fluid storage tank to the ammonia recovery section 500. 【0135】 Preferably, in the second ammonia recovery step, nitrogen is supplied when the primary recovery of ammonia is completed, thereby pushing out any remaining ammonia in the pipes such as the fuel supply line and fuel return line within the system and recovering the ammonia in a secondary manner. Preferably, the pressure of the supplied nitrogen is 5 bar to 6 bar, and the ammonia to be recovered in a secondary manner is also supplied to the ejector 200, and the ammonia supplied to the ejector 200 is supplied to the ammonia recovery section. 【0136】 Preferably, ammonia dissolves in the working fluid, nitrogen passes through the buffer plate 330, and is then discharged overboard from the top of the working fluid storage tank. 【0137】 The second ammonia leak detection step is performed to prevent ammonia that has flowed into the working fluid storage tank 310 via the air discharge line after a leak has been detected in the first ammonia leak detection step from leaking overboard. Preferably, the ammonia concentration is measured by the second ammonia sensor 360 while the air that has flowed into the working fluid storage tank 310 is discharged to the outside. 【0138】 Preferably, the second ammonia sensor 360 is set to maintain the ammonia concentration at 20 ppm or less, and if the ammonia concentration exceeds 20 ppm, the chiller 400 is operated so that the ammonia dissolves in the working fluid (fresh water). 【0139】 For example, if the ammonia concentration measured by the second ammonia sensor 360 exceeds 20 ppm, the chiller 400 is operated to cool the working fluid and increase the solubility of ammonia, thereby maintaining the ammonia concentration measured by the second ammonia sensor 360 at 20 ppm or less. 【0140】 Preferably, if the ammonia concentration measured by the second ammonia sensor 360 is 20 ppm or higher even after operating the chiller 400 to cool the working fluid, the dilution fan is operated to dilute the ammonia in the ammonia dilution chamber 370 and maintain the ammonia concentration at 20 ppm or lower. 【0141】 Preferably, the ammonia diluted in the ammonia dilution chamber 370 is recovered in the working fluid storage tank 310, and the ammonia recovered in the working fluid storage tank 310 dissolves in the working fluid and is recovered in the ammonia recovery unit 500. 【0142】 For example, if the ammonia concentration measured by the second ammonia sensor 360 exceeds 20 ppm, the chiller 400 is operated to cool the working fluid and increase the solubility of ammonia, thereby maintaining the ammonia concentration measured by the second ammonia sensor 360 at 20 ppm or less. 【0143】 Preferably, if the ammonia concentration measured by the second ammonia sensor 360 is 20 ppm or higher, the dilution fan is operated to maintain the ammonia concentration in the ammonia dilution chamber 370 at 20 ppm or lower. 【0144】 When the ammonia concentration measured by the second ammonia sensor 360 falls below 20 ppm, it is preferable to control the cooling temperature of the chiller 400 to gradually raise the temperature of the working fluid in the working fluid storage tank 310, and then, when the ammonia concentration measured by the second ammonia sensor 360 falls below 20 ppm, to continuously discharge the working fluid (ammonia water) containing dissolved ammonia to the ammonia recovery unit 500. This reduces the ammonia content of the working fluid in the working fluid storage tank 310, and allows the ammonia to be maintained in a saturated ammonia water state at room temperature. Preferably, the process of discharging ammonia water from the working fluid storage tank 310 to the ammonia recovery unit 500 is carried out until the ammonia concentration measured by the second ammonia sensor 360 becomes 0 ppm. 【0145】 The ammonia water supplied to the ammonia water recovery unit is separated into a working fluid and ammonia. The process includes the steps of supplying ammonia water to an ammonia water tank 700, heating the ammonia water tank 700 to the evaporation temperature of ammonia, supplying the ammonia evaporated in the ammonia water tank 700 to a gas-water separator 740 to separate it into ammonia and a working fluid, supplying the separated ammonia to an ammonia compressor 750 to compress it, and supplying the compressed ammonia to a combustion unit for combustion and reuse as fuel oil. 【0146】 The ammonia water supplied to the ammonia water tank 700 is heated so that only ammonia evaporates. Preferably, the electric heater 710 is set to raise the temperature to about 80°C or below to separate the ammonia evaporation gas from the working fluid. 【0147】 Preferably, a working fluid collector (clean water collector) is provided in the ammonia water tank 700 to separate the working fluid evaporated together with the ammonia evaporation gas, and the evaporated working fluid is primarily separated by the working fluid collector. 【0148】 Preferably, if the evaporated working fluid is not separated in the primary separation step, the ammonia evaporated gas and the evaporated working fluid are supplied to the gas-liquid separator 740 for secondary separation. 【0149】 Preferably, the separated working fluid is supplied to the ejector 200 via the working fluid recovery line WRL, and the working fluid supplied to the ejector 200 is recovered in the working fluid storage tank 310. 【0150】 Preferably, the ammonia evaporated gas separated in the gas-water separator 740 is supplied to the ammonia compressor 750 and compressed to 8 bar to 10 bar. 【0151】 Depending on the type of boiler equipped with a combustion section 800, the ammonia compressed in the ammonia compressor 750 may be supplied in a gaseous state, or it may be supplied to the cooler 760 to be liquefied and then supplied as liquid ammonia. 【0152】 Preferably, when liquefying compressed ammonia, the compressed ammonia is supplied to the cooler 760, and the chiller 400 is operated to cool it to 10°C and liquefy it. 【0153】 Preferably, ammonia that has passed through the ammonia compressor 750 or cooler 760 is supplied to the combustion section 800, where it is burned and reused as fuel. 【0154】 Preferably, after supplying the ammonia water in the working fluid storage tank 310 to the ammonia recovery unit 500, the working fluid replenishment valve 350 is opened to supply working fluid to the working fluid storage tank 310. At this time, the working fluid is stored in the working fluid storage tank 310 via the packing material unit 320, and the ammonia present in the packing material unit 320 dissolves, minimizing ammonia vaporization, so that as much ammonia as possible remains in the working fluid (fresh water). 【0155】 As described above, the present invention provides an ammonia recovery and discharge system and a control method. 【0156】 Furthermore, the ammonia recovery and discharge system and method of the present invention uses water (freshwater) during operation, which significantly reduces the risk of leakage. 【0157】 It also has the effect of preventing ammonia from being released into the atmosphere. 【0158】 Furthermore, to prevent ammonia from being released into the atmosphere, separating ammonia from ammonia water (which contains dissolved ammonia gas) allows for the reuse of ammonia and safe discharge overboard. 【0159】 The above description is merely illustrative of the technical concept of the present invention, and those skilled in the art in which the present invention pertains can make various modifications, changes, and substitutions within the bounds of the essence of the present invention. Therefore, the embodiments and accompanying drawings disclosed herein are explanatory, not limiting, the scope of the technical concept of the present invention, and the embodiments and accompanying drawings do not limit the scope of the technical concept of the present invention. The scope of protection of the present invention shall be interpreted by the following claims, and all technical concepts within the same scope shall be interpreted as being included within the scope of the rights of the present invention.

Claims

[Claim 1] In ammonia recovery and discharge systems for ships using ammonia fuel, Ammonia tanks for storing liquid ammonia; and, An engine located in the engine compartment and powered by fuel supplied from an ammonia tank; A fuel supply unit equipped with a fuel supply line that supplies ammonia fuel from an ammonia tank to the engine; and, A fuel recovery unit equipped with a fuel return line that recovers ammonia not consumed by the engine into an ammonia tank; and, An air supply line that supplies air to the fuel supply line and the fuel return line; and, An air exhaust line for discharging air supplied to the fuel supply line and fuel return line; and, A working fluid circulation section through which working fluid circulates in order to discharge air or ammonia from the fuel supply line and fuel return line; An ejector provided in the working fluid circulation section, which supplies high-pressure working fluid to circulate air or ammonia into the working fluid circulation section; Ammonia recovery and discharge system. [Claim 2] The aforementioned working fluid circulation unit, A working fluid storage tank for storing and recovering the working fluid supplied to the ejector; and A first vent line for discharging air supplied to the working fluid storage tank overboard; A chiller for cooling the working fluid that flows into the working fluid storage tank; and It comprises an ammonia recovery unit for recovering ammonia that has flowed into the working fluid circulation unit; The working fluid storage tank is connected to the ejector via the working fluid supply line. The ejector is connected to the working fluid storage tank via a working fluid recirculation line. The ammonia recovery and discharge system according to claim 1. [Claim 3] A portion of the fuel supply line and fuel return line is provided within the engine compartment. The fuel supply line and fuel return line in the engine compartment are constructed as double pipes. The annular space formed between the inner and outer tubes of the double-walled pipe is connected to an air supply line and an air discharge line. The air supply line and the air discharge line are connected to the ejector, and the air discharge line is A first ammonia sensor for measuring ammonia concentration; and A pressure sensor for measuring airflow; and A circulation shut-off valve that controls air circulation when ammonia operation is interrupted; and The air supplied to the annular space via the aforementioned air supply line is supplied to the ejector via the air discharge line, and the air supplied to the ejector flows into the working fluid storage tank via the working fluid recirculation line. The ammonia recovery and discharge system according to claim 1. [Claim 4] The first vent line is provided at the upper end of one end of the working fluid storage tank. A second ammonia sensor is provided in the first vent line. The air discharged overboard via the aforementioned air discharge line passes through the buffer plate. The ammonia recovery and discharge system according to claim 3. [Claim 5] The working fluid storage tank is connected to the ammonia recovery unit via an ammonia water supply line. When ammonia is detected by the first ammonia sensor, the supply of ammonia fuel is interrupted. Ammonia that flows in through the aforementioned air discharge line is supplied to the packing material section and dissolves in the working fluid. The ammonia dissolved in the working fluid passes through the buffer plate and is then supplied to the ammonia recovery section from the bottom of the working fluid storage tank. The ammonia recovery and discharge system according to claim 4. [Claim 6] A liquid fuel supply system is provided in the aforementioned fuel supply line. A fuel valve train region is provided on the fuel supply line and fuel return line downstream of the fuel supply system section. The fuel supply line is connected to the ejector via a first ammonia recovery line, and the fuel return line is connected to the ejector via a second ammonia recovery line. The ammonia recovery and discharge system according to claim 1. [Claim 7] A first double shut-off valve is provided in the fuel supply line of the fuel valve train region. A second double shut-off valve is provided in the fuel return line of the fuel valve train region. The first double shut-off valve is connected to the ejector via the third ammonia recovery and discharge line. The second double shut-off valve is connected to the ejector via the fourth ammonia recovery and discharge line. The ammonia recovery and discharge system according to claim 6. [Claim 8] An ammonia dilution unit for diluting ammonia that flows into the working fluid storage tank; further comprising, The ammonia dilution section is provided between the working fluid storage tank and the first vent line. The ammonia dilution unit comprises an ammonia dilution chamber into which ammonia is supplied and diluted; and a dilution fan for diluting the ammonia in the ammonia dilution chamber. The ammonia recovery and discharge system according to claim 2. [Claim 9] The ammonia recovery unit flows into the working fluid storage tank and recovers the ammonia dissolved in the working fluid, and the ammonia recovery unit, An ammonia water tank is supplied with ammonia water from the working fluid storage tank and separates the ammonia into ammonia and working fluid by evaporating the ammonia; and A gas-water separator is provided at the top of the ammonia water tank to separate the evaporated working fluid from the ammonia: An ammonia compressor for compressing the ammonia separated in the aforementioned gas-liquid separator; and, A combustion section is provided which compressed ammonia is supplied and the compressed ammonia is burned and reused as fuel; The ammonia recovery and discharge system according to claim 2. [Claim 10] The ammonia recovery unit further includes a cooler, The cooler operates the chiller to cool the ammonia. If the ammonia compressed by the ammonia compressor is in a gaseous state, it is supplied to a cooler to be liquefied, and the liquefied ammonia is supplied to the combustion section. The ammonia recovery and discharge system according to claim 9. [Claim 11] The working fluid storage tank is connected to an ammonia water tank via an ammonia water supply line. The ammonia water supply line is branched from the working fluid supply line and is equipped with an ammonia water discharge selection valve. The ammonia water tank is connected to the ejector via a working fluid recovery line. A working fluid recovery valve is provided in the working fluid recovery line. The ammonia recovery and discharge system according to claim 9. [Claim 12] A fuel supply step includes supplying ammonia fuel from an ammonia tank to the engine by a fuel supply unit including a fuel supply line; During the fuel supply step, a working fluid circulation step is performed, in which high-pressure working fluid is supplied to and circulated to an ejector provided in the working fluid circulation section; If the fuel supply step is interrupted, an ammonia recovery step is performed to recover ammonia in the ammonia recovery unit; A method for controlling an ammonia recovery and discharge system. [Claim 13] The working fluid circulation step includes an air circulation step of supplying air to the fuel supply line and the fuel return line and discharging the supplied air; The air circulation step includes an air supply step of supplying air to the annular space of the double-pipe fuel supply line and fuel return line; The air discharge step includes supplying air flowing into the annular space to an ejector, the air supplied to the ejector flowing into a working fluid storage tank via a working fluid recirculation line, and the air flowing into the working fluid storage tank passing through a buffer plate and then being discharged to the outside from the top; A method for controlling an ammonia recovery and discharge system according to claim 12. [Claim 14] Further equipped with an ammonia leak detection step, The ammonia leak detection step includes a first ammonia leak detection step that detects ammonia leakage from the inner pipe to the outer pipe in a double-walled pipe; A second ammonia leak detection step for detecting ammonia leakage from the working fluid storage tank; and a second ammonia leak detection step for detecting ammonia leakage from the working fluid storage tank; A method for controlling an ammonia recovery and discharge system according to claim 12. [Claim 15] The first ammonia leak detection step is: When the first ammonia sensor detects an ammonia leak, the operation of the engine and the supply of ammonia fuel are interrupted, and an ammonia recovery step is performed. A first ammonia recovery step involves recovering ammonia fuel present in the fuel supply line and fuel return line into an ammonia recovery unit; and, A second ammonia recovery step includes supplying nitrogen to the fuel supply line to recover ammonia remaining in the fuel supply line and fuel return line; A method for controlling an ammonia recovery and discharge system according to claim 14. [Claim 16] The ammonia recovered in the ejector in the first ammonia recovery step flows into the working fluid storage tank. The ammonia that flows into the working fluid storage tank is supplied to the packing material section. The ammonia supplied to the filler section is dissolved in the working fluid. The ammonia (ammonia water) dissolved in the working fluid passes through the buffer plate and is supplied to and recovered in the ammonia recovery section from the bottom of the working fluid storage tank. A method for controlling an ammonia recovery and discharge system according to claim 15. [Claim 17] The ammonia water supplied to the ammonia recovery unit is separated into the working fluid and ammonia, and the separation of the ammonia water is performed as follows: The steps of supplying the ammonia water to the ammonia water tank; and, The steps of heating the ammonia water tank to the evaporation temperature of ammonia; The steps include: supplying the ammonia evaporated from the ammonia water tank to a gas-water separator to separate it into ammonia and working fluid; The steps of supplying the separated ammonia to a compressor and compressing it; The step of supplying the compressed ammonia to a combustion chamber and burning it for reuse as fuel; A method for controlling an ammonia recovery and discharge system according to claim 16. [Claim 18] The second ammonia leak detection step is: The system includes a cooling step in which, upon detecting an ammonia leak with the second ammonia sensor, the chiller is operated so that the ammonia concentration measured by the second ammonia sensor falls below 20 ppm, thereby cooling the working fluid (ammonia water) in which ammonia is dissolved in the working fluid storage tank; If the ammonia concentration is 20 ppm or less after the cooling step, the cooling temperature of the chiller is controlled to gradually increase, and the working fluid in which ammonia has been dissolved in the working fluid storage tank is supplied to the ammonia recovery unit. A method for controlling an ammonia recovery and discharge system according to claim 14.

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