Marine ammonia treatment system

Abstract

This reduces the emission of unburned ammonia gas in processing furnaces installed on ships. [Solution] A marine ammonia treatment system installed on a ship equipped with a tank for storing liquid ammonia, comprising: a treatment furnace that introduces and burns exhaust gas discharged from the tank after the liquid ammonia has been discharged, together with a combustion aid and a carbon-containing fuel; a concentration measuring device installed in the treatment furnace for measuring the concentration of predetermined components contained in the combustion gas; a flow rate adjustment mechanism that adjusts the introduction flow rate of at least one of the exhaust gas, the combustion aid, or the carbon-containing fuel introduced into the treatment furnace; and a control unit that controls the flow rate adjustment mechanism, wherein the control unit controls the flow rate adjustment mechanism based on the measurement value measured by the concentration measuring device.

Description

Technical Field

[0001] The present invention relates to an ammonia treatment system for ships.

Background Art

[0002] Hydrogen has attracted attention as an energy that does not emit carbon dioxide during combustion. Since hydrogen has a low liquefaction temperature and high transportation costs, it is transported as ammonia, which has a higher liquefaction temperature than hydrogen.

[0003] When storing liquid ammonia in a tank and transporting it by ship, the liquid ammonia is transferred to another tank at the destination, and the ship returns, and the liquid ammonia is stored again. At this time, since the remaining liquid ammonia vaporizes and fills the tank, it is necessary to exhaust this ammonia gas outside the tank.

[0004] In addition, this tank needs to be inspected regularly from the inside. Also at this time, after draining the liquid ammonia, it is necessary to exhaust the ammonia gas filling the tank outside the tank. However, since ammonia is harmful to the human body, it cannot be discharged directly into the atmosphere.

[0005] Patent Document 1 discloses an ammonia treatment system that re-liquefies ammonia gas generated on a ship with a re-liquefaction device and then neutralizes and detoxifies it with a neutralization device.

[0006] However, in the ammonia treatment system of Patent Document 1, not only a neutralization device but also a re-liquefaction device is required, so there is a problem that it takes up space on a ship with limited space.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The applicant began developing an ammonia treatment system that burns ammonia gas in a treatment furnace, aiming to obtain an ammonia treatment system that can directly neutralize ammonia gas without reliquefaction. However, they encountered a problem in that ammonia gas, air, and carbon-containing fuel were not introduced into the treatment furnace at the appropriate flow rates, sometimes resulting in the discharge of unburned ammonia gas.

[0009] Therefore, the main objective of the present invention is to suppress the emission of unburned ammonia gas in a treatment furnace that can directly neutralize ammonia gas.

[0010] In order to solve the aforementioned problems, the applicant continued research and development and discovered that if the concentration of a predetermined component contained in the combustion gas is known, the flow rates of ammonia gas, combustion aids, and carbon-containing fuel introduced into the furnace can be adjusted to be more optimal for burning ammonia gas, leading to the present invention. [Means for solving the problem]

[0011] In other words, the marine ammonia treatment system according to the present invention is a marine ammonia treatment system installed on a ship equipped with a tank for storing liquid ammonia, comprising: a treatment furnace that introduces and burns exhaust gas discharged from the tank after the liquid ammonia has been discharged, together with a combustion aid gas and a carbon-containing fuel; a concentration measuring device installed in the treatment furnace for measuring the concentration of predetermined components contained in the combustion gas; a flow rate adjustment mechanism that adjusts the introduction flow rate of at least one of the exhaust gas, the combustion aid gas, or the carbon-containing fuel introduced into the treatment furnace; and a control unit that controls the flow rate adjustment mechanism, wherein the control unit controls the flow rate adjustment mechanism based on the measured value measured by the concentration measuring device.

[0012] According to the present invention, ammonia gas can be rendered harmless by direct combustion, thus reducing the installation space compared to the ammonia treatment system described in Patent Document 1.

[0013] Furthermore, by measuring the concentration of predetermined components in the combustion gas and controlling the flow rate adjustment mechanism based on these component concentrations, the flow rates of ammonia gas, auxiliary combustion gases, and carbon-containing fuel introduced into the furnace can be adjusted to a more optimal flow rate for burning ammonia gas. As a result, the emission of unburned ammonia gas is suppressed compared to conventional processing furnaces.

[0014] Specifically, there is a correlation between the concentration of certain components in the combustion gas and the mixing ratio of ammonia gas and carbon-containing fuel introduced into the furnace. By utilizing this relationship, the flow rates of ammonia gas, auxiliary combustion gas, and carbon-containing fuel introduced into the furnace can be adjusted to the optimal flow rate for burning ammonia gas.

[0015] Therefore, the control unit may be equipped with a relational data storage unit that stores relational data in advance, showing the relationship between the component concentration of a predetermined component contained in the combustion gas and the mixing ratio of ammonia gas and carbon-containing fuel introduced into the furnace, and the flow rate adjustment mechanism may be controlled based on the measured value measured by the concentration measuring device and the relational data.

[0016] Ammonia does not emit carbon dioxide when burned with air and carbon-containing fuel. Focusing on this point, the applicant found that the relevant data could be obtained by measuring the carbon dioxide concentration in the combustion gas.

[0017] Therefore, the combustion-supporting gas may be air, and the concentration measuring device may measure the carbon dioxide concentration as the component concentration.

[0018] In this case, the applicant confirmed that the theoretical relationship data derived by assuming that the oxygen concentration in the combustion gas is a predetermined value (hereinafter also referred to as "theoretical relationship data") substantially matches the relationship data obtained experimentally (hereinafter also referred to as "experimental relationship data").

[0019] When using this theoretical relationship data, it is necessary to convert the measured carbon dioxide concentration to the carbon dioxide concentration under the assumed conditions.

[0020] Therefore, the relational data is derived assuming that the oxygen concentration contained in the combustion gas is a predetermined value On, the concentration measuring device further measures the oxygen concentration, and the control unit is based on the measured value Cs of the carbon dioxide concentration and the measured value Os of the oxygen concentration measured by the concentration measuring device and the following conversion formula. It may further include a concentration conversion unit that converts the measured value Cs of the carbon dioxide concentration into a value adjusted to the predetermined value On, and controls the flow rate adjustment mechanism based on the conversion value C calculated by the concentration conversion unit and the relational data. TIFF0007836129000002.tif14169Om: Oxygen concentration in the air introduced into the processing furnace

[0021] The processing furnace is provided with a chimney for discharging the combustion gas, and a cooling gas is introduced into the chimney to cool the combustion gas. Therefore, if the concentration measuring device is provided in the chimney, there is a risk that the cooling gas will mix with the combustion gas and accurate measurement will become impossible.

[0022] Therefore, it may further include a pressure holding mechanism that holds the inside of the processing furnace at a positive pressure, the processing furnace includes a lead-out pipe that leads out the combustion gas from the furnace interior, and the concentration measuring device is provided in the lead-out pipe.

[0023] With such a configuration, the component concentration of a predetermined component contained in the combustion gas in the furnace can be measured more accurately, so that more accurate flow rate adjustment is possible.

[0024] By the way, some ships are propelled using liquid ammonia as fuel. In this case, the tank that stores the liquid ammonia as fuel, in other words, the fuel tank, also needs to be inspected regularly from the inside.

[0025] Therefore, the ship may be one that is propelled using the liquid ammonia as fuel, and the tank may be a fuel tank.

Effects of the Invention

[0026] According to the ammonia treatment system for ships according to the present invention, in the treatment furnace mounted on the ship, the discharge of unburned ammonia gas can be suppressed.

Brief Description of the Drawings

[0027] [Figure 1] It is a schematic diagram showing a ship equipped with the ammonia treatment system for ships of the first embodiment. [Figure 2] It is a cross-sectional view schematically showing the treatment furnace of the ammonia treatment system for ships of the first embodiment. [Figure 3] It is a block diagram showing the control unit of the ammonia treatment system for ships of the first embodiment. [Figure 4] It is a graph showing the related data of the first embodiment.

Embodiments for Carrying out the Invention

[0028] Hereinafter, the ammonia treatment system for ships according to the present invention will be described based on the drawings.

[0029] The ammonia treatment system for ships according to the present invention is mounted on a ship that uses liquid ammonia as cargo or fuel. And it is used by being directly or indirectly connected to a tank for storing liquid ammonia as cargo (that is, a transport tank) or a tank for storing liquid ammonia as fuel (that is, a fuel tank).

[0030] <First Embodiment> The ammonia treatment system 100 for ships according to this embodiment is mounted on a ship S that uses liquid ammonia as cargo. As shown in FIG. 1, this ship S is provided with a transport tank T for storing liquid ammonia, and the ammonia treatment system for ships is connected to this transport tank T.

[0031] The ammonia treatment system 100 for ships includes a replacement device 10, a treatment furnace 20, a combustion-supporting gas supply device 30, a carbon-containing fuel supply device 40, a flow rate adjustment mechanism 50, a concentration measurement device 60, and a control unit 70.

[0032] The replacement device 10 is connected to the transport tank T and replaces the ammonia gas filling the transport tank T with an inert gas. Specifically, it introduces an inert gas from an inert gas storage tank T1 into the transport tank T and exhausts the ammonia gas filling the transport tank T along with the inert gas. In this embodiment, nitrogen gas is used as the inert gas, but it is not limited to this, and other gases such as argon gas may also be used.

[0033] The processing furnace 20 is connected to the transport tank T via an exhaust line EL, and introduces and burns exhaust gas discharged from the transport tank T. Specifically, as shown in Figure 2, it comprises a furnace body 21 in the shape of a box, a chimney 22 provided on the upper surface of the furnace body 21, and an outlet pipe 23 that discharges a portion of the combustion gas generated inside the furnace from the furnace body 21. In this embodiment, one end of the outlet pipe 23 is connected to the furnace body 21, and the other end is connected to the chimney 22. In other words, a portion of the combustion gas is discharged directly from inside the furnace as a sample. More specifically, it is discharged temporarily from inside the furnace.

[0034] A first nozzle N1 and a second nozzle N2 protrude from the inner surface of the furnace body 21. Both nozzles N1 and N2 protrude from the same surface and in the same direction. Therefore, both nozzles N1 and N2 eject in the same direction. The other end of the outlet pipe 23 is connected to the opposing surfaces of these two nozzles N1 and N2 in the ejection direction. In this embodiment, exhaust gas discharged from the transport tank T is introduced into the furnace via the first nozzle N1.

[0035] The combustion-supporting gas supply device 30 supplies combustion-supporting gas to the processing furnace 20. In this embodiment, it includes an air supply pump P and a combustion-supporting line L1 connected to the air supply pump P and the second nozzle N2, and introduces air taken in from the outside by the air supply pump P into the processing furnace 20 via the combustion-supporting line L1. In other words, in this embodiment, air is used as the combustion-supporting gas. The combustion-supporting gas is not limited to this, and may be oxygen gas, for example.

[0036] The carbon-containing fuel supply device 40 supplies carbon-containing fuel to the processing furnace 20. In this embodiment, the device includes a kerosene storage tank T2 and a fuel line L2 that connects the kerosene storage tank T2 to the middle of the auxiliary combustion line L1. The kerosene supplied from the kerosene storage tank T2 is mixed in a mist form into the air flowing through the auxiliary combustion line L1 via the fuel line L2 and introduced into the processing furnace 20. In other words, in this embodiment, kerosene is used as the carbon-containing fuel. The carbon-containing fuel is not limited to this, and may be methane, for example. In other words, in this embodiment, a fuel-mixed gas in which kerosene is mixed in a mist form into the air is introduced into the furnace via the second nozzle N2.

[0037] The flow rate adjustment mechanism 50 adjusts at least one of the flow rates of exhaust gas, combustion aid gas, and carbon-containing fuel introduced into the processing furnace 20. In this embodiment, flow rate adjustment mechanisms 50a, 50b, and 50c are installed in the exhaust line EL, combustion aid line L1, and fuel line L2, respectively. Note that the flow rate adjustment mechanism 50 does not necessarily need to be installed in all lines; for example, it may be installed only in the combustion aid line L1 through which the combustion aid gas flows.

[0038] The concentration measuring device 60 measures the concentration of predetermined components contained in the combustion gas generated in the furnace. In this embodiment, it is installed in the middle of the outlet pipe 23 and measures the carbon dioxide concentration and oxygen concentration.

[0039] Specifically, the control unit 70 is an information processing device such as a personal computer equipped with a CPU, memory, etc., and based on the program stored in the memory, it performs at least the functions of a related data storage unit 71, a conversion formula storage unit 72, a concentration conversion unit 73, and a flow rate control unit 74, as shown in Figure 3.

[0040] The aforementioned relational data storage unit 71 stores relational data in advance that shows the relationship between the component concentration of a predetermined component contained in the combustion gas and the mixing ratio (hereinafter also simply referred to as "mixing ratio") of ammonia gas and carbon-containing fuel introduced into the processing furnace 20, and is provided in a part of the memory area. This relational data may be in the form of a table or a relational expression. In this embodiment, it is the graph shown in Figure 4.

[0041] In this embodiment, the component concentrations are carbon dioxide concentration and oxygen concentration. Therefore, determining the mixing ratio requires identifying these two variables. Consequently, obtaining the relevant data experimentally is extremely time-consuming.

[0042] Therefore, in this embodiment, we assume that the oxygen concentration is "On" and use the relationship data derived under this assumption. In other words, we use theoretical relationship data.

[0043] The procedure for deriving the aforementioned theoretical data will now be explained. In this explanation, the deriving procedure is based on the assumption that the oxygen concentration in the combustion gas produced when 1 kg of ammonia gas is burned using 1 kg of kerosene is 0 n%. Furthermore, the composition of the gases and the auxiliary combustion gas (air) used in this calculation, as well as the mass of each element, are assumed to be as follows. The gas is assumed to be an ideal gas with a volume of 22.4 L per mole at 0°C, 101.32 kPa. The composition of air is assumed to be 79% nitrogen and 21% oxygen by volume. The masses of each element are assumed to be 1 kg / kmol for hydrogen (H), 12 kg / kmol for carbon (C), 14 kg / kmol for nitrogen (N), 16 kg / kmol for oxygen (O), and 32 kg / kmol for sulfur (S).

[0044] First, the theoretical amount of air A1, which is the amount of air required to completely burn 1 kg of kerosene, is calculated based on the following formula (1). Hereinafter, c is the amount of carbon (kg / kg) contained in 1 kg of kerosene, h is the amount of hydrogen (kg / kg) contained in 1 kg of kerosene, o is the amount of oxygen (kg / kg) contained in 1 kg of kerosene, and s is the amount of sulfur (kg / kg) contained in 1 kg of kerosene. TIFF0007836129000003.tif16169

[0045] Next, the air ratio m is calculated based on the following formula (2). When burning kerosene in the processing furnace 20, it is difficult to achieve complete combustion by supplying only the theoretical amount of air A1. For this reason, in practice, more air than the theoretical amount of air A1 is supplied. The ratio of the amount of this excess air A to the theoretical amount of air A1 is the air ratio m. TIFF0007836129000004.tif13169

[0046] Next, the amount of combustion gas V generated when 1 kg of kerosene is completely burned is calculated based on the following formula (3). This amount of combustion gas V can be calculated by adding the amount of water vapor Vw and the amount of dry gas Vd in the combustion gas. Therefore, the amount of water vapor Vw is calculated based on the following formula (4), and the amount of dry gas Vd is calculated based on the following formula (5). Note that w is the amount of water contained in 1 kg of kerosene (kg / kg), but since kerosene does not contain water, it is 0. TIFF0007836129000005.tif46169

[0047] Next, the carbon dioxide concentration (CO2n) in this combustion gas is calculated based on the following formula (6). TIFF0007836129000006.tif15169

[0048] Next, the theoretical amount of air A2, which is the amount of air required to completely combust 1 kg of ammonia gas, is calculated based on the following formula (7). Here, Oo is the theoretical amount of oxygen required to completely combust 1 kg of ammonia gas, and can be calculated based on the following formula (8). Also, x represents the carbon molecular weight in ammonia, and y represents the hydrogen molecular weight in ammonia. TIFF0007836129000007.tif33169

[0049] Next, the amount of combustion gas G generated when 1 kg of ammonia gas is completely combusted is calculated based on the following formula (9). This amount of combustion gas G can be calculated by adding the amount of oxygen VO2, the amount of nitrogen VN2, and the amount of water vapor VH2O in the combustion gas. Therefore, the amount of oxygen VO2 is calculated based on the following formula (10), the amount of nitrogen VN2 is calculated based on the following formula (11), and the amount of water vapor VH2O is calculated based on the following formula (12). Note that n is the molecular weight of hydrogen in ammonia. TIFF0007836129000008.tif41169

[0050] Finally, the theoretical relationship data is derived from the following equations (13) and (14). Here, X is the amount of kerosene, Y is the amount of ammonia gas, CO2z is the carbon dioxide concentration under the assumed conditions, and NH3z is the ratio of kerosene to the total combustion gas (the sum of the combustion gas produced when 1 kg of kerosene is burned and the combustion gas produced when 1 kg of ammonia gas is burned) under the assumed conditions. TIFF0007836129000009.tif26169

[0051] When using this theoretical relationship data, it is necessary to convert the measured carbon dioxide concentration obtained by the concentration measuring device 60 to the carbon dioxide concentration C (hereinafter referred to as the converted carbon dioxide concentration) under the assumed conditions.

[0052] The conversion formula storage unit 72 stores this conversion formula (formula (15) below) in advance and is located in a part of the memory area. Here, Cs represents the measured value of carbon dioxide concentration, Os represents the measured value of oxygen concentration, and Om represents the oxygen concentration in air (combustion aid gas). TIFF0007836129000010.tif17169

[0053] The concentration conversion unit 73 acquires the measured values ​​Cs and Os of carbon dioxide concentration and oxygen concentration, respectively, measured by the concentration measuring device 60, and calculates the converted carbon dioxide concentration C from these measured values ​​Cs and Os and formula (15).

[0054] The flow control unit 74 derives the mixing ratio MR of ammonia gas and kerosene introduced into the processing furnace 10 from the converted carbon dioxide concentration C and theoretical relationship data, and controls the flow rate adjustment mechanism 50 based on this mixing ratio MR. In this embodiment, the flow rate adjustment mechanism 50 is controlled to adjust the air introduction flow rate. Specifically, it is controlled so that the unburned ammonia gas of the combustion gas generated in the processing furnace 10 is below a standard value. This standard value is, for example, a value set by the government. More preferably, it is controlled so that the ammonia gas is burned as efficiently (fuel-efficiently) as possible.

[0055] More specifically, the flow control unit 74 derives the mixing ratio MR and then calculates GASCV from the following formula (16). Here, GASCV represents the ratio of the amount of heat generated from the ammonia gas introduced into the furnace to the rated heat output of the processing furnace 20, and OILCV represents the ratio of the amount of heat generated from the kerosene introduced into the furnace to the rated heat output of the processing furnace 20. The rated heat output refers to the amount of heat generated when a theoretical amount of air is introduced into the processing furnace 20 and complete combustion is performed. TIFF0007836129000011.tif16169

[0056] Next, GASCV is added to OILCV to calculate FUELCV. Here, FUELCV represents the ratio of the amount of heat generated from the mixture of ammonia gas and kerosene introduced into the furnace to the rated heat output of the processing furnace 20. Then, AIRCV is calculated by multiplying this FUELCV by the air ratio m. Here, AIRCV represents the ratio of air actually required to completely combust the ammonia gas introduced into the processing furnace, based on the theoretical amount of air. Based on this AIRCV, the flow rate control mechanism 50b is controlled to adjust the flow rate of air supplied from the auxiliary combustion gas supply mechanism flow 30.

[0057] Specifically, for example, the control unit 70 is provided with a control quantity storage unit that stores in advance the control quantity (e.g., valve opening) of the flow rate adjustment mechanism 50 for introducing a theoretical amount of air into the processing furnace 20, and the control is performed based on the control quantity stored in this control quantity storage unit and the value of AIRCV. More specifically, if the value of AIRCV is 120, the control is performed so that 20% more air flows than the theoretical amount.

[0058] According to this embodiment, the carbon dioxide concentration and oxygen concentration in the combustion gas are measured, and the flow rate adjustment mechanism 50 is controlled based on these component concentrations. This allows the flow rates of ammonia gas, air, and kerosene introduced into the processing furnace 10 to be adjusted to a more optimal level for burning ammonia gas. As a result, the emission of unburned ammonia gas is suppressed compared to conventional processing furnaces.

[0059] Furthermore, the combustion gas discharged from the chimney 22 is mixed with low-temperature air to lower its temperature. Therefore, if only a portion of the combustion gas passing through the chimney 22 is taken as a sample, it is not possible to accurately measure the carbon dioxide concentration in the combustion gas. On the other hand, in this embodiment, a portion of the combustion gas is taken directly from inside the furnace as a sample, and the carbon dioxide concentration contained in the taken-out combustion gas is measured, so the carbon dioxide concentration in the combustion gas can be measured more accurately. As a result, the flow rates of ammonia gas, air, and kerosene introduced into the furnace can be adjusted to more appropriate levels.

[0060] <Other Embodiments> This embodiment is not limited to the above embodiment. In the above embodiment, theoretical relational data derived from the above-mentioned assumptions was used as relational data, but this is not limited to this. For example, experimental relational data obtained in an experiment may be used. In this case, there is no need to convert the measured values ​​of the concentration measuring device, so a conversion formula storage unit and a concentration conversion unit are not necessary.

[0061] Furthermore, while carbon dioxide concentration and oxygen concentration were used as component concentrations in the above embodiment, the system is not limited to these. For example, carbon monoxide may be used.

[0062] Furthermore, in the above embodiment, the control unit is configured to control the flow rate of air introduced into the processing furnace, i.e., the flow rate of the combustion aid gas, but it is not limited to this. For example, it may be configured to control the flow rate of carbon-containing fuel or ammonia gas, or it may be configured to control multiple flow rates.

[0063] Furthermore, although the above embodiment connected the marine ammonia treatment system to a transport tank, it is not limited to this. For example, if the ship is propelled by liquid ammonia, it may be connected to a fuel tank that stores the liquid ammonia.

[0064] Furthermore, various combinations or modifications of parts of the embodiments are permitted, as long as they do not contradict the spirit of the present invention. [Explanation of Symbols]

[0065] 100 Marine Ammonia Treatment Systems S ship T Tank (Transport Tank) 10 Replacement device 20 Processing reactors 21 Furnace body 22 Chimneys 23 Outlet pipe 30. Combustion aid gas supply device 40. Carbon-containing fuel supply device 50 Flow rate adjustment mechanism 60 Concentration measuring device 70 Control Unit 71 Related Data Storage Unit 72 Conversion formula storage unit 73 Concentration conversion section 74 Flow Control Unit

Claims

1. A marine ammonia treatment system installed on a ship equipped with a tank for storing liquid ammonia, A processing furnace is provided for burning the exhaust gas discharged from the tank after the liquid ammonia has been discharged, together with a combustion aid gas and a carbon-containing fuel. A concentration measuring device installed in the aforementioned processing furnace for measuring the carbon dioxide concentration contained in the combustion gas, A flow rate adjustment mechanism for adjusting the flow rate of at least one of the exhaust gas, the combustion aid gas, or the carbon-containing fuel introduced into the processing furnace, The system includes a control unit that controls the flow rate adjustment mechanism, A marine ammonia treatment system characterized in that the control unit controls the flow rate adjustment mechanism based on the measurement value measured by the concentration measuring device.

2. The ammonia treatment system for ships according to claim 1, wherein the control unit includes a relational data storage unit that stores relational data showing the relationship between the carbon dioxide concentration contained in the combustion gas and the mixing ratio of ammonia gas and carbon-containing fuel introduced into the furnace, and controls the flow rate adjustment mechanism based on the measured value measured by the concentration measuring device and the relational data.

3. The ammonia treatment system for ships according to claim 2, wherein the auxiliary combustion gas is air.

4. The aforementioned related data was derived by assuming that the oxygen concentration in the combustion gas is a predetermined value, On. The aforementioned concentration measuring device further measures the oxygen concentration, The ammonia treatment system for ships according to claim 3, wherein the control unit further comprises a concentration conversion unit that converts the measured carbon dioxide concentration Cs to a value matching the predetermined value On based on the measured carbon dioxide concentration Cs and measured oxygen concentration Os measured by the concentration measuring device and the following conversion formula, and controls the flow rate adjustment mechanism based on the converted value C calculated by the concentration conversion unit and the related data. Om: Oxygen concentration in the air introduced into the processing furnace

5. The processing furnace is further equipped with a pressure-holding mechanism that maintains a positive pressure inside the furnace. The aforementioned processing furnace is equipped with an outlet pipe for dischargering combustion gas from inside the furnace, The ammonia treatment system for ships according to claim 1, wherein the concentration measuring device is provided in the outlet pipe.

6. The aforementioned vessel is propelled by the aforementioned liquid ammonia as fuel, The ammonia treatment system for ships according to claim 1, wherein the tank is a fuel tank.

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