Ammonia removal system, floating body, and ammonia supply method

Abstract

Further improve the efficiency of ammonia removal. [Solution] The ammonia removal system comprises a gas flow line through which ammonia-containing gas flows, a first dilution unit that absorbs ammonia contained in the ammonia-containing gas supplied from the gas flow line into a first absorbent liquid under pressurized conditions, a first discharge line that can discharge the gas in the gas phase within the first dilution unit as a primary treatment gas to the outside of the first dilution unit, and a control valve provided in the first discharge line that adjusts the supply of the primary treatment gas from the first dilution unit to the outside of the first dilution unit.

Description

Technical Field

[0001] The present disclosure relates to an ammonia detoxification system, a floating body, and an ammonia supply method.

Background Art

[0002] In a floating body such as a ship, ammonia may be transported as a load. Also, ammonia may be used as fuel for a main engine or the like provided in the floating body. Such a floating body handling ammonia includes a tank for storing ammonia and pipes through which ammonia flows connected to the tank.

[0003] A tank storing liquefied ammonia may generate ammonia gas as boil-off gas when the liquefied ammonia in the tank evaporates due to heat input from the outside. In this case, in order to prevent the pressure inside the tank from rising excessively due to the generation of ammonia gas, the generated ammonia gas may be discharged to the outside of the tank.

[0004] Also, for example, when some trouble occurs or the like, the ammonia in the pipe may be discharged by purging the inside of the pipe with an inert gas such as nitrogen. In this case, a purge gas containing ammonia and an inert gas is discharged from the pipe.

[0005] Ammonia may affect the surrounding environment. Therefore, it is not preferable to directly release the boil-off gas (ammonia gas) and the purge gas discharged from the tank or the pipe into the water or the atmosphere around the floating body.

[0006] Patent Document 1 discloses an ammonia gas detoxification system that detoxifies ammonia gas before releasing it into the atmosphere. In this detoxification system, a gas containing ammonia is introduced into a closed space such as a scrubber or a cooling tower and brought into sufficient contact with water to absorb the ammonia component into the water.

Prior Art Documents

[0007] [Patent Document 1] Japanese Patent Publication No. 2006-026555 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, since ammonia removal systems installed on floating bodies must be placed in a limited space, there is a need to further improve the efficiency of ammonia removal.

[0009] This disclosure was made to solve the above-mentioned problems and aims to provide an ammonia removal system, a floating body, and an ammonia supply method that can further improve the efficiency of ammonia removal. [Means for solving the problem]

[0010] To solve the above problems, the ammonia abatement system according to this disclosure comprises a gas flow line, a first dilution section, a first discharge line, and a control valve. Ammonia-containing gas flows through the gas flow line. The first dilution section absorbs the ammonia contained in the ammonia-containing gas supplied from the gas flow line into a first absorbent liquid under pressurized conditions. The first discharge line is capable of discharging the gas in the gas phase within the first dilution section as a primary treatment gas to the outside of the first dilution section. The control valve is provided in the first discharge line. The control valve adjusts the supply of the primary treatment gas from the first dilution section to the outside of the first dilution section.

[0011] The floating body relating to this disclosure comprises a floating body body and an ammonia removal system as described above. The ammonia supply method according to this disclosure adjusts the amount of ammonia water supplied to the denitrification device or the concentration of the ammonia water based on at least one of the nitrogen oxide concentration of the exhaust gas discharged from the denitrification device and the ammonia concentration of the exhaust gas discharged from the denitrification device. [Effects of the Invention]

[0012] The ammonia removal system, floating body, and ammonia supply method of this disclosure can further improve the efficiency of ammonia removal. [Brief explanation of the drawing]

[0013] [Figure 1] This is a side view of a floating body equipped with an ammonia removal system according to an embodiment of the present disclosure. [Figure 2] This figure shows the configuration of the ammonia removal system according to the first embodiment of this disclosure. [Figure 3] This figure shows the configuration of the ammonia removal system in a first modified example of the first embodiment of the present disclosure. [Figure 4] This figure shows the configuration of the ammonia removal system in a second modified example of the first embodiment of the present disclosure. [Figure 5] This figure shows the configuration of the ammonia removal system in a third modified example of the first embodiment of the present disclosure. [Figure 6] This figure shows the configuration of the ammonia removal system according to the second embodiment of this disclosure. [Figure 7] This figure shows the configuration of the ammonia removal system in the first modified example of the second embodiment of the present disclosure. [Figure 8] This figure shows the configuration of an ammonia removal system according to the third embodiment of this disclosure. [Figure 9] This figure shows the configuration of the ammonia removal system in the first modified example of the third embodiment of the present disclosure. [Figure 10] This figure shows the configuration of an ammonia removal system according to a modified example of the first to third embodiments of this disclosure.

Mode for Carrying Out the Invention

[0014] <First Embodiment> Hereinafter, an ammonia removal system, a floating body, and an ammonia supply method according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 9.

[0015] (Overall Configuration of the Floating Body) As shown in FIG. 1, the floating body 1 of the embodiment of the present disclosure includes a floating body main body 2, an upper structure 4, a combustion device 8, and an ammonia removal system 100A. Note that the floating body 1 of this embodiment will be described by taking a ship that can navigate by a main engine or the like as an example. The ship type of the floating body 1 is not limited to a specific ship type. Examples of the ship type of the floating body 1 include a liquefied gas carrier, a ferry, a RORO ship, an automobile carrier, a passenger ship, and the like. In this embodiment, the case where the floating body 1 is a ship will be described, but the floating body 1 is not limited to a ship, and it may be an FSU (Floating Storage Unit), an FSRU (Floating Storage and Regasification Unit), etc. that cannot navigate by a main engine or the like.

[0016] The floating body main body 2 is formed to float on seawater. The floating body main body 2 has a pair of side plates 5A and 5B forming its outer shell and a bottom 6. The side plates 5A and 5B include a pair of side outer plates forming the left and right side plates respectively. The bottom 6 includes a bottom outer plate connecting these side plates 5A and 5B. The floating body main body 2 further includes an upper deck 7 which is an all-through deck arranged at the uppermost layer. The upper structure 4 is formed on this upper deck 7. Living quarters and the like are provided in the upper structure 4. In the floating body 1 of this embodiment, for example, a cargo space (not shown) for loading cargo is provided on the bow 2a side in the fore-and-aft direction FA rather than the upper structure 4. Note that the configuration of the floating body main body 2 is not limited in any way, and other configurations than those described above may be used.

[0017] The combustion device 8 is a device that generates thermal energy by burning fuel, and is provided inside the floating body main body 2 described above. Examples of the combustion device 8 include an internal combustion engine used as a main engine for propelling the floating body 1, an internal combustion engine used for a power generation facility that supplies electricity to the ship, a boiler that generates steam as a working fluid, and the like. The combustion device 8 used as the main engine in the floating body 1 of this embodiment can, for example, switch between using ammonia as fuel and other fuels such as heavy oil different from ammonia. A fuel system (not shown) for supplying fuel is connected to the combustion device 8. The fuel system allows ammonia and other fuels to flow through it.

[0018] When switching the fuel of the combustion device 8 from ammonia to other fuels or performing maintenance, a so-called purge is performed to replace the ammonia remaining in the piping system including the fuel system of the combustion device 8 with an inert gas (purge gas) such as nitrogen. Here, the ammonia remaining in the piping system may be liquefied ammonia or ammonia gas. To perform the purge, an inert gas supply device (not shown) is connected to the piping system. The inert gas supply device is capable of supplying an inert gas to the piping system. The inert gas only needs to be a gas that does not chemically react when it comes into contact with ammonia. For example, nitrogen can be cited. In the inert gas supply device, when an inert gas is supplied from an inert gas supply source (not shown) to the piping system, the ammonia in the piping system is pushed out by the inert gas. As a result, a purge gas containing ammonia (liquefied ammonia, ammonia gas) and the inert gas is discharged from the piping system.

[0019] (Configuration of Ammonia Decontamination System) FIG. 2 is a diagram showing the configuration of an ammonia decontamination system according to the first embodiment of the present disclosure. As shown in FIG. 2, the ammonia decontamination system 100A includes a gas flow line 10, a first dilution unit 20, a first delivery line 30, a second dilution unit 50, a second delivery line 70, a third dilution unit 80, and a control device 60.

[0020] The gas distribution line 10 carries ammonia-containing gas. Examples of ammonia-containing gas include purge gas discharged from the piping system of the combustion device 8 (see Figure 1) during purging, boil-off gas discharged from the ammonia tank, and gas containing ammonia that has leaked and vaporized from piping, etc. The gas distribution line 10 guides the circulating ammonia-containing gas to the ammonia abatement system 100A.

[0021] A shut-off valve 15 is provided in the middle of the gas flow line 10. The shut-off valve 15 is capable of opening and closing the flow path within the gas flow line 10. The opening and closing operation of the shut-off valve 15 is controlled by a control device 60, which will be described later. The shut-off valve 15 may also be a control valve whose opening degree can be adjusted. Furthermore, the combination of the gas distribution line 10 and the bypass line 110, which will be described later, is not limited to one, and multiple combinations may be provided.

[0022] The first dilution section 20 absorbs ammonia contained in the ammonia-containing gas supplied from the gas flow line 10 into the first absorbent liquid L1 under pressurized conditions. The first dilution section 20 has a hollow structure and stores the first absorbent liquid L1, which is capable of absorbing ammonia, inside. Examples of the first absorbent liquid L1 include fresh water and seawater. A gas phase and a liquid phase are formed inside the first dilution section 20. The first dilution section 20 is a pressure vessel into which ammonia-containing gas is introduced through the gas flow line 10. Here, the ammonia-containing gas flowing through the gas flow line 10 is pressurized to a pressure higher than atmospheric pressure. Therefore, the ammonia-containing gas introduced into the first dilution section 20 is in a pressurized state, at a pressure higher than atmospheric pressure. The ammonia component contained in the ammonia-containing gas introduced into the first dilution section 20 is then absorbed into the first absorbent liquid L1 under pressurized conditions. In the first dilution section 20 of this embodiment, for example, the ammonia contained in the gas phase is absorbed into the first absorbent liquid L1 until the gas phase and liquid phase in the first dilution section 20 reach a gas-liquid equilibrium state.

[0023] Here, in order to promote the absorption of ammonia by the first absorbent liquid L1, the first dilution section 20 may, for example, be configured to draw up the liquid phase within the first dilution section 20 and spray it into the upper gas phase within the first dilution section 20 via a spray nozzle or the like. As a result, the first absorbent liquid L1 contained in the liquid phase comes into contact with the ammonia in the gas phase within the first dilution section 20, and the absorption of ammonia is promoted.

[0024] The first discharge line 30 is capable of discharging the gas phase gas in the first dilution section 20 as primary treatment gas G1 to the outside of the first dilution section 20. One end of the first discharge line 30 is in communication with the upper part of the first dilution section 20. The other end of the first discharge line 30 is connected to the second dilution section 50. In other words, the first discharge line 30 is capable of discharging the primary treatment gas G1 to the second dilution section 50.

[0025] A control valve 35 is provided in the middle of the first discharge line 30. The control valve 35 can adjust the supply of primary gas from the first dilution section 20 to the second dilution section 50. Here, the opening degree of the control valve 35 may be adjusted by switching the flow path in the first discharge line 30 between an open state and a closed state, thereby intermittently controlling the flow of gas. The control valve 35 can also adjust the flow rate of gas flowing through the flow path in the first discharge line 30 by adjusting the opening degree of the flow path in the first discharge line 30. The operation of the control valve 35 can be controlled by the control device 60.

[0026] The second dilution unit 50 is connected to the first delivery line 30. The second dilution unit 50 absorbs ammonia contained in the primary treatment gas G1 supplied through the first delivery line 30 into the second absorbent liquid L2 at a lower pressure than the first dilution unit 20. In this embodiment, the second dilution unit 50 absorbs ammonia contained in the primary treatment gas G1 into the second absorbent liquid L2 at atmospheric pressure.

[0027] The second discharge line 70 can discharge the gas phase gas in the second dilution section 50 as secondary treatment gas G2 to the outside of the second dilution section 50. One end of the second discharge line 70 is in communication with the upper part of the second dilution section 50. The other end of the second discharge line 70 is connected to the third dilution section 80.

[0028] The third dilution unit 80 reduces the concentration of ammonia contained in the secondary treatment gas G2 supplied through the second delivery line 70. Any material can be used for the third dilution unit 80 as long as it can reduce the concentration of ammonia contained in the secondary treatment gas G2. Examples of the third dilution unit 80 include a dilution fan, a GCU (Gas Combustion Unit), and a catalytic combustion device. A dilution fan reduces the ammonia concentration in the secondary treatment gas G2 by mixing outside air (air) taken in from the outside with the secondary treatment gas G2. A GCU (Gas Combustion Unit) and a catalytic combustion device reduce the ammonia concentration in the gas by burning the ammonia contained in the secondary treatment gas G2. The third dilution unit 80 may also absorb the ammonia contained in the secondary treatment gas G2 using an absorbent material capable of absorbing ammonia, such as activated carbon. Furthermore, the third dilution unit 80 may be a so-called wet type, similar to the second dilution unit 50, which absorbs the ammonia contained in the secondary treatment gas G2 using an absorbent liquid such as water. Note that the third dilution section 80 is not an essential component. It is possible to have a configuration without the third dilution section 80. In addition, other dilution sections (for example, a fourth dilution section, etc.: not shown) may be provided downstream of the second dilution section 50, in addition to the third dilution section 80.

[0029] An exhaust line 90 is connected to the third dilution section 80. The exhaust line 90 discharges the gas, from which ammonia has been removed by the third dilution section 80, into the atmosphere. As the exhaust line 90, for example, a vent post or funnel 9 (see Figure 1) installed on the upper deck 7 of the floating body 2 can be used.

[0030] The control device 60 controls at least the opening and closing operations of the on-off valve 15 and the control valve 35. The control device 60 opens the on-off valve 15 when ammonia-containing gas is introduced into the first dilution section 20 from the gas flow line 10. The control device 60 closes the on-off valve 15 when gas is discharged from the gas phase in the first dilution section 20 to the outside through the first discharge line 30. The control device 60 controls the operation of the on-off valve 15 and the control valve 35 to temporarily store the ammonia-containing gas in the first dilution section 20 until the gas phase and liquid phase in the first dilution section 20 reach a gas-liquid equilibrium state, thereby performing so-called batch processing. However, the control objects of the control device 60 are not limited to the opening and closing operations of the on-off valve 15 and the control valve 35. For example, if the ammonia abatement system 100A is equipped with a pump (not shown), the control device 60 may also control the operation of the pump (not shown), etc.

[0031] The control device 60 monitors the ammonia concentration in the gas phase within the first dilution unit 20. When the ammonia concentration in the gas phase within the first dilution unit 20 falls below a specified value, the control device 60 switches the control valve 35 from a closed state to an open state. In this embodiment, when the gas phase within the first dilution unit 20 and the liquid phase within the first dilution unit 20 reach a gas-liquid equilibrium state, the control device 60 sends the gas from the gas phase within the first dilution unit 20 to the second dilution unit 50.

[0032] The specified value mentioned above is, for example, an ammonia concentration higher than the ammonia concentration when gas-liquid equilibrium is reached. When gas-liquid equilibrium is presumed to have been reached, the ammonia concentration in the gas phase within the first dilution section 20 is below the specified value. An example of the specified value is an ammonia concentration slightly higher than the ammonia concentration at gas-liquid equilibrium. Here, generally speaking, gas-liquid equilibrium is a state in which mass transfer between the gas phase and the liquid phase has completely ceased. However, strictly speaking, since the temperature is constantly changing, albeit slightly, mass transfer is always occurring.

[0033] The control device 60 closes the control valve 35 when ammonia-containing gas is introduced into the first dilution section 20 from the gas flow line 10.

[0034] Furthermore, control in the control device 60 is not limited to the computer sequentially executing predetermined processes based on a pre-set program, but also includes so-called remote operation, in which, for example, an operator who observes detected values ​​from a pressure sensor or the like performs a predetermined operation on the control device 60, causing the control device 60 to operate the on-off valve 15 and the control valve 35.

[0035] Furthermore, the ammonia removal system 100A in this embodiment is further equipped with a bypass line 110. The bypass line 110 bypasses the first dilution section 20 and connects the gas flow line 10 and the first discharge line 30. One end of the bypass line 110 is connected to the gas flow line 10 upstream of the on-off valve 15. The other end of the bypass line 110 is connected to the first discharge line 30 downstream of the control valve 35. A valve 115 is provided in the middle of the bypass line 110 to open and close the flow path within the bypass line 110. With the on-off valve 15 and the control valve 35 closed, the ammonia-containing gas flowing through the gas flow line 10 can be bypassed to the first discharge line 30 without passing through the first dilution section 20 by opening the valve 115. Note that this bypass line 110 is not a mandatory component, and the system can be configured without it. Furthermore, the control device 60 may be configured to control the opening and closing of the valve 115.

[0036] (Effects and Benefits) In the first embodiment described above, ammonia contained in the ammonia-containing gas supplied from the gas flow line 10 is absorbed into the first absorbent liquid L1 under pressurized conditions in the first dilution section 20. The gas in the gas phase within the first dilution section 20 is then discharged to the outside of the first dilution section 20 through the first discharge line 30 as primary treatment gas G1. Furthermore, in the second dilution section 50, the ammonia contained in the primary treatment gas G1 is absorbed into the second absorbent liquid L2 under a lower pressure than that of the first dilution section 20. This allows the ammonia-containing gas to be retained in the first dilution section 20, making it possible to decontaminate ammonia in batch processing. Therefore, it is possible to decontaminate ammonia with a simple system configuration without using absorption towers or other equipment that are affected by the tilt of the ship. Consequently, the efficiency of ammonia decontamination can be further increased.

[0037] Furthermore, in the first embodiment described above, the first dilution section 20 maintains a gas-liquid equilibrium state between the gas phase and the liquid phase within the first dilution section 20. This allows the ammonia contained in the ammonia-containing gas supplied from the gas flow line 10 to be absorbed to the maximum extent by the first absorbent liquid L1. Therefore, the ammonia concentration in the gas phase of the first dilution section 20 can be sufficiently reduced before being sent to the second dilution section 50.

[0038] Furthermore, in the first embodiment described above, the control device 60 switches the control valve 35 from a closed state to an open state when the ammonia concentration in the gas phase within the first dilution unit 20 falls below a specified value. As a result, the ammonia-containing gas in the first dilution unit 20 is sufficiently absorbed by the first absorbent liquid L1, and the primary treated gas G1 with an ammonia concentration below a specified value can be supplied to the second dilution unit 50. This reduces the load of ammonia absorption in the second dilution unit 50.

[0039] Furthermore, in the first embodiment described above, the second dilution unit 50 absorbs ammonia contained in the primary treatment gas G1 into the second absorption liquid L2 under atmospheric pressure. This allows the second dilution unit 50 to have a simple configuration that does not require equipment such as a pump for pressurization.

[0040] Furthermore, in the first embodiment described above, a bypass line 110 is provided that bypasses the first dilution unit 20 and connects the gas flow line 10 and the first delivery line 30. This allows the residual pressure of the gas in the gas flow line 10 to be quickly released through the bypass line 110 when releasing residual pressure in the gas flow line 10, etc.

[0041] Furthermore, the first embodiment described above includes a third dilution section 80. Secondary treatment gas G2, which is the gas phase gas in the second dilution section 50, is supplied to the third dilution section 80 through the second delivery line 70. In the third dilution section 80, the concentration of ammonia contained in the secondary treatment gas G2 can be further reduced.

[0042] Furthermore, in the first embodiment described above, if the ammonia-containing gas is a purge gas containing an inert gas, the purge gas is supplied to the first dilution section 20 through the gas flow line 10. The purge gas supplied from the gas flow line 10 is temporarily stored in the first dilution section 20 under pressurized conditions, and the ammonia contained in the purge gas is absorbed by the first absorbent liquid L1. Subsequently, the primary treatment gas G1, which is the gas phase gas in the first dilution section 20, is supplied to the second dilution section 50 through the discharge line, and in the second dilution section 50, the ammonia contained in the primary treatment gas G1 is absorbed by the second absorbent liquid L2. Therefore, ammonia contained in the purge gas that flows in in large quantities through the gas flow line 10 during purging can be efficiently removed.

[0043] Furthermore, if the ammonia-containing gas flowing through the gas flow line 10 is boil-off gas generated in the ammonia tank, similar to the case of the purge gas described above, the boil-off gas supplied from the gas flow line 10 can be temporarily stored under pressure in the first dilution section 20, allowing the ammonia from the boil-off gas to be absorbed into the first absorbent liquid L1. In addition, the primary treatment gas G1 can be supplied to the second dilution section 50, allowing the ammonia contained in the primary treatment gas G1 to be absorbed into the second absorbent liquid L2 within the second dilution section 50. This allows the ammonia contained in the boil-off gas generated in a tank capable of storing ammonia to be efficiently removed by the first dilution section 20 and the second dilution section 50.

[0044] (Modification of the first embodiment) In the first embodiment described above, the ammonia-containing gas is batch-processed in the first dilution unit 20. However, if the ammonia concentration of the ammonia-containing gas is low, the on-off valve 15 and the control valve 35 may be kept open, allowing the ammonia-containing gas flowing from the gas flow line 10 into the first dilution unit 20 to be processed continuously.

[0045] Furthermore, in the first embodiment described above, the method for absorbing the ammonia contained in the primary treatment gas G1 into the second absorbent liquid L2 may be a so-called bubbling method, in which the piping of the first delivery line 30 is directly submerged in the second absorbent liquid L2 and the primary treatment gas G1 is released into the second absorbent liquid L2 to bring it into gas-liquid contact. This makes it possible to improve the absorption efficiency of ammonia into the second absorbent liquid L2 while keeping the second dilution unit 50 simple in configuration.

[0046] (First modification of the first embodiment) Figure 3 shows the configuration of an ammonia removal system in a first modified example of the first embodiment of the present disclosure. In the first embodiment described above, the case in which only one set of bypass lines 110 and valves 115 is provided was explained. However, as shown in the first modified example in Figure 3, bypass lines 110A and 110B may be provided as bypass lines 110, and valves 115A and 115B may be provided as valves 115 (the same applies to the second and third embodiments below). Valve 115A is provided on bypass line 110A, and valve 115B is provided on bypass line 110B. In other words, valve 115B is provided in parallel with valve 115A. As a result, even if either valve 115A or 115B malfunctions, the other can back it up and release the residual pressure in the gas flow line 10. Note that three or more bypass lines 110 and valves 115 may be provided.

[0047] (Second modification of the first embodiment) Figure 4 shows the configuration of an ammonia removal system in a second modified example of the first embodiment of the present disclosure. In the first embodiment described above, an example was shown in which an on-off valve 15 is provided in the gas flow line 10 and a valve 115 is provided in the bypass line 110. However, as shown in the second modified example in Figure 4, a single three-way valve 415 may be provided instead of the on-off valve 15 and valve 115 (the same applies to the second and third embodiments below). In this second modified example, as in the first modified example above, a bypass line 110B and valve 115B may be provided in parallel with the bypass line 110A and the three-way valve 415. By doing so, even if the three-way valve 415 malfunctions, it becomes possible to release the residual pressure in the gas flow line 10.

[0048] (Third modified example of the first embodiment) Figure 5 shows the configuration of an ammonia removal system in a third modified example of the first embodiment of the present disclosure. In addition to the first embodiment described above, a mixing unit 63 that promotes the absorption of ammonia by the second absorbent liquid L2 may be provided, as shown in the third modified example of the first embodiment in Figure 5 (the same applies to the third embodiment below). The mixing unit 63 mixes the ammonia-containing gas or primary treatment gas G1 flowing through the first delivery line 30 with the second absorbent liquid L2 stored in the second dilution unit 50. The mixing unit 63 includes a branch line 76, a mixer 77, an absorbent liquid supply line 78, and an absorbent liquid circulation pump 79. The branch line 76 branches off from the first delivery line 30 and leads the ammonia-containing gas or primary treatment gas G1 flowing through the first delivery line 30 to the mixer 77. The mixer 77 mixes the ammonia-containing gas or primary treatment gas G1, which is a gas flowing through the first delivery line 30, with the second absorbent liquid L2. As the mixer 77, for example, an ejector, a static mixer, or a microreactor can be used. As a result of mixing by the mixer 77, the ammonia-containing gas flowing through the first discharge line 30 or the ammonia gas contained in the primary treatment gas G1 is more easily absorbed by the absorbent liquid. The absorbent liquid supply line 78 supplies the second absorbent liquid L2 from the second dilution section 50 to the mixer 77. The absorbent liquid circulation pump 79 sends the second absorbent liquid L2 from the absorbent liquid supply line 78 toward the mixer 77. The mixed fluid mixed by the mixing section 63 is introduced into the second dilution section 50.

[0049] In the third modification of the first embodiment described above, for example, an on / off valve (not shown) may be provided to allow selection between a flow path that directly flows from the first discharge line 30 to the second dilution section 50 and a flow path that flows from the first discharge line 30 via a branch line 76, a mixer 77, and an absorbent liquid supply line 78. Also, in the third modification of the first embodiment described above, in order to promote the absorption of ammonia by the second absorbent liquid L2 stored in the second dilution section 50, for example, the absorbent liquid may be sprayed into the upper gas phase in the second dilution section 50 via a spray nozzle or the like from the absorbent liquid supply line 78.

[0050] <Second Embodiment> Next, the ammonia abatement system and floating body according to the second embodiment of this disclosure will be described. This second embodiment differs from the first embodiment only in the configuration, which includes an air introduction line 260 and a gas suction section 200. Therefore, using Figure 1, the same parts as in the first embodiment will be denoted by the same reference numerals and redundant explanations will be omitted.

[0051] (Configuration of the ammonia removal system) Figure 6 shows the configuration of an ammonia removal system according to the second embodiment of this disclosure. As shown in Figure 6, the ammonia abatement system 100B includes a gas flow line 10, a first dilution section 20, a first discharge line 30, a second dilution section 50, a second discharge line 70, a third dilution section 80, a control device 60, an air introduction line 260, and a gas suction section 200.

[0052] Furthermore, the ammonia abatement system 100B in this embodiment includes an introduction line 220 that introduces ammonia-containing gas into the second dilution section 50 from a gas flow line 10B located at a different position from the gas flow line 10 connected to the first dilution section 20. The introduction line 220 is connected to the first discharge line 30 downstream of the control valve 35, for example. The introduction line 220 may also be connected directly to the second dilution section 50 instead of the first discharge line 30. An on / off valve 221 is provided in the introduction line 220.

[0053] The gas flow line 10B and the introduction line 220 are connected by a connecting line 230. An on / off valve 231 is provided in the middle of the connecting line 230. Although the description above describes the case in which the introduction line 220 introduces ammonia-containing gas from the gas flow line 10B to the second dilution section 50, the introduction line 220 may be a different gas flow line (not shown) from the gas flow lines 10 and 10B.

[0054] Furthermore, the gas flow line 10B is connected to an inert gas introduction line 240 and an air introduction line 260. The inert gas introduction line 240 supplies inert gas (e.g., nitrogen gas) to the gas flow line 10B from the outside when purging is performed. The air introduction line 260 supplies air to the gas flow line 10B from the outside. An on-off valve 241 is provided in the middle of the inert gas introduction line 240. An on-off valve 261 is provided in the middle of the air introduction line 260. The opening and closing operations of the above on-off valves 221, 231, 241, and 261 are controlled by the control device 60.

[0055] In this configuration, when purging is performed, the shut-off valve 241 is opened, and inert gas is sent into the piping system, including the gas flow line 10B. The inert gas sent into the piping system, along with the ammonia in the piping system, is sent as purge gas through the gas flow line 10 to the first dilution unit 20. Furthermore, as the purging of the piping system progresses and the ammonia concentration in the piping decreases (for example, when the ammonia concentration falls below the explosive limit), valve 241 is closed and valve 261 is opened. This allows air to be supplied from the outside to the piping system, including the gas flow line 10B, through the air introduction line 260. As a result, the amount of inert gas used during purging can be reduced.

[0056] When air is supplied to the gas flow line 10B through the air introduction line 260, the ammonia concentration in the piping system is low. In such cases, the on / off valves 231 and 221 may be opened to supply ammonia-containing gas from the gas flow line 10B through the connection line 230 and introduction line 220 to the first discharge line 30 and then to the second dilution section 50.

[0057] The gas suction unit 200 draws ammonia-containing gas into the second dilution unit 50 from outside the second dilution unit 50. The gas suction unit 200 draws ammonia-containing gas flowing through the gas flow line 10B into the second dilution unit 50 from the gas flow line 10B, for example. As the gas suction unit 200, for example, an ejector 205 or a mixer (not shown) can be used. In this embodiment, the case in which the gas suction unit 200 is equipped with an ejector 205 is illustrated.

[0058] The ejector 205 is installed, for example, in the middle of the supply line 207 that supplies the second absorbent liquid L2 into the second dilution section 50. The supply line 207 pumps the second absorbent liquid L2 by a pump 208 or the like installed in the middle of the supply line 207. The ejector 205 has a connection line 209 connected to the introduction line 220. An on / off valve 203 is provided in the middle of the connection line 209.

[0059] The ejector 205 uses the second absorbent liquid L2, which is being pumped, as its driving fluid. The negative pressure generated when the second absorbent liquid L2 passes through the ejector 205 can be applied to the introduction line 220 and the gas flow line 10B through the connection line 209. Specifically, by opening the on / off valve 203 and applying the negative pressure generated in the ejector 205 to the introduction line 220 and the gas flow line 10B, the ammonia-containing gas in the gas flow line 10B is drawn in and sent to the second dilution unit 50 through the ejector 205 and the liquid supply line 207.

[0060] Such suction by the ejector 205 may be performed, for example, towards the end of the purge or after the purging is completed. This allows the ammonia-containing gas remaining in the gas flow line 10B after purging to be sucked out by the gas suction unit 200 and sent to the second dilution unit 50, making it possible to process a small amount of ammonia-containing gas in the second dilution unit 50. Furthermore, suction by the ejector 205 may be performed for other purposes, such as reducing the residual pressure in the piping system including the gas flow line 10B.

[0061] (Effects and Benefits) In the second embodiment described above, a gas suction unit 200 is provided to draw ammonia-containing gas into the second dilution unit 50 from outside the second dilution unit 50. This allows the ammonia contained in the ammonia-containing gas drawn in by the gas suction unit 200 to be absorbed by the second absorbent liquid L2 in the second dilution unit 50.

[0062] Furthermore, in the second embodiment described above, the gas suction unit 200 draws ammonia-containing gas flowing through the gas flow line 10B into the second dilution unit 50 from the gas flow line 10B. This allows the gas suction unit 200 to draw in any remaining ammonia-containing gas in the gas flow line 10B when the gas flow line 10B is purged. The ammonia contained in the remaining ammonia-containing gas in the gas flow line 10 can then be absorbed by the second absorbent liquid L2 in the second dilution unit 50. Therefore, it is possible to further reduce the ammonia concentration in the gas flow line 10 during purging.

[0063] Furthermore, similar to the first embodiment described above, the ammonia contained in the ammonia-containing gas can be efficiently removed by passing it through the first dilution section 20 and the second dilution section 50, thereby increasing the efficiency of ammonia removal.

[0064] (Modified version of the second embodiment) To promote the absorption of ammonia by the second absorbent liquid L2 in the second dilution section 50 of the second embodiment described above, for example, the liquid may be sprayed into the upper gas phase of the second dilution section 50 via a spray nozzle or the like from the supply line 207. Alternatively, as a method for absorbing the ammonia contained in the primary treatment gas G1 into the second absorbent liquid L2, the piping of the first delivery line 30 may be directly submerged in the second absorbent liquid L2, thereby releasing the primary treatment gas G1 into the second absorbent liquid L2 and causing gas-liquid contact.

[0065] Furthermore, while the second embodiment described above illustrates a case where the opening and closing operations of the on-off valves 203, 221, 231, 241, and 261 are controlled by the control device 60, the configuration is not limited to this. For example, the opening and closing operations of the on-off valves 203, 221, 231, 241, and 261 may be performed manually by an operator or the like.

[0066] Furthermore, in the second embodiment described above, the case in which the inert gas supplied to the piping system is supplied as a purge gas to the first dilution section 20 through the gas flow line 10 together with the ammonia in the piping system was explained. However, it is not limited to this, and for example, the purge gas can be supplied from the gas flow line 10 to the second dilution section 50 through the bypass line 110 without being supplied to the first dilution section 20.

[0067] (First modified example of the second embodiment) Figure 7 shows the configuration of an ammonia removal system in a first modified example of the second embodiment of the present disclosure. In the second embodiment described above, the gas suction unit 200 sucks ammonia-containing gas from the gas flow line 10B and sends it to the second dilution unit 50, but the configuration is not limited to this. For example, the gas suction unit 200 may suck primary treatment gas G1 as ammonia-containing gas from the first dilution unit 20 into the second dilution unit 50. In this case, for example, as shown in Figure 7, the system may be equipped with another connection line 209B that branches off from the first delivery line 30 and leads to the gas suction unit 200, and an on / off valve 203B provided on the other connection line 209 that opens and closes the other connection line 209. Furthermore, the gas suction unit 200 may be configured to draw ammonia-containing gas from other parts besides the gas flow line 10B and the first dilution unit 20.

[0068] <Third Embodiment> Next, an ammonia abatement system and a floating body according to the third embodiment of this disclosure will be described. This third embodiment differs from the first and second embodiments only in that it includes a tank 300, an ammonia water production unit 310, a denitrification device 320, and a denitrification processing unit 350. Therefore, using Figure 1, the same parts as in the first and second embodiments will be denoted by the same reference numerals and redundant explanations will be omitted.

[0069] (Configuration of the ammonia removal system) Figure 8 shows the configuration of an ammonia removal system according to an embodiment of this disclosure. As shown in Figure 8, the ammonia abatement system 100C comprises a gas flow line 10, a first dilution section 20, a first discharge line 30, a second dilution section 50, a second discharge line 70, a third dilution section 80, a control device 60, a tank 300, an ammonia water production section 310, a denitrification device 320, and a denitrification processing section 350.

[0070] Tank 300 is capable of storing ammonia. Tank 300 is capable of storing ammonia as fuel for, for example, a combustion device 8. The ammonia stored in Tank 300 may be, for example, ammonia as cargo for a floating vessel 1.

[0071] The ammonia water production unit 310 includes an ammonia water storage tank 311, a first connection line 312, and a second connection line 313.

[0072] The ammonia water storage tank 311 is capable of storing the ammonia water produced in the ammonia water production unit 310. The first connection line 312 connects the ammonia water storage tank 311 to the liquid phase of the first dilution unit 20. An on / off valve (not shown) is provided in the middle of the first connection line 312, which allows for the intermittent supply of ammonia liquid from the liquid phase of the first dilution unit 20 to the ammonia water storage tank 311. The second connection line 313 connects the ammonia water storage tank 311 to the liquid phase of the second dilution unit 50. An on / off valve (not shown) is provided in the middle of the second connection line 313, which allows for the intermittent supply of ammonia liquid from the liquid phase of the second dilution unit 50 to the ammonia water storage tank 311.

[0073] The ammonia water production unit 310 is capable of receiving fresh water or seawater from the ammonia water storage tank 311 through a water supply line (not shown). The ammonia water production unit 310 generates ammonia water by mixing ammonia solution introduced from at least one of the liquid phases of the first dilution unit 20 and the second dilution unit 50 with water.

[0074] Furthermore, the ammonia water production unit 310 is capable of receiving ammonia stored in the tank 300. For this reason, the ammonia water production unit 310 has a first tank connection line 315 and a second tank connection line 316.

[0075] The first tank connection line 315 connects the ammonia water production unit 310 to the liquid phase of the tank 300. An on / off valve (not shown) is provided in the middle of the first tank connection line 315, which allows for the intermittent supply of ammonia liquid from the liquid phase of the tank 300 to the ammonia water storage tank 311 of the ammonia water production unit 310. The second tank connection line 316 connects the ammonia water production unit 310 to the gas phase of tank 300. An on / off valve (not shown) is provided in the middle of the second tank connection line 316, which allows for the intermittent supply of ammonia gas from the gas phase of tank 300 to the ammonia water storage tank 311.

[0076] The ammonia water production unit 310 can adjust the concentration of ammonia produced in the ammonia water storage tank 311 by introducing ammonia stored in tank 300. Furthermore, the ammonia water production unit 310 may also accept ammonia gas remaining after the ammonia in tank 300 has been removed, or ammonia gas such as boil-off gas generated in tank 300 due to external heat input, into the ammonia water storage tank 311.

[0077] The ammonia water produced in the ammonia water production unit 310 can be used within the floating body 1 for any appropriate purpose. In this embodiment, for example, the ammonia water produced in the ammonia water production unit 310 is used as a reducing agent in the denitrification device 320.

[0078] The denitrification unit 320 denitrifies the exhaust gas discharged from the combustion unit 8 that burns the fuel. The denitrification unit 320 and the ammonia water storage tank 311 are connected via a reducing agent supply line 321. A pump (not shown) is provided in the reducing agent supply line 321 to supply ammonia water stored in the ammonia water storage tank 311 to the denitrification unit 320 as a reducing agent. The ammonia water supplied to the denitrification unit 320 through the reducing agent supply line 321 only needs to have a concentration sufficient to decompose nitrogen oxides in the denitrification unit 320.

[0079] The denitrification unit 320 uses ammonia water, which is produced in the ammonia water production unit 310 and supplied through the reducing agent supply line 321, as a reducing agent to denitrify the exhaust gas. The exhaust gas that has been denitrified in the denitrification unit 320 is discharged through the exhaust line 325 connected to the denitrification unit 320 from the funnel 9 (see Figure 1), etc.

[0080] In this third embodiment, a NOx detection unit S1 and an ammonia detection unit S2 are further included. The NOx detection unit S1 detects the concentration of nitrogen oxides on the exhaust side of the denitrification device 320. The ammonia detection unit S2 detects the ammonia concentration on the exhaust side of the denitrification device 320. In this embodiment, the amount of ammonia water supplied from the ammonia water production unit 310 to the denitrification device 320 and the concentration of the ammonia water produced by the ammonia water production unit 310 are adjusted so that the concentration of nitrogen oxides detected by the NOx detection unit S1 is below the regulatory limit. In addition, in this embodiment, the amount of ammonia water supplied to the denitrification device 320 is adjusted based on the detection result of the ammonia detection unit S2 to prevent excessive supply of ammonia water to the denitrification device 320. Note that the NOx detection unit S1 and the ammonia detection unit S2 may be provided as needed and may be omitted.

[0081] The denitrification section 350 is capable of denitrifying the ammonia-containing wastewater discharged from at least one of the liquid phases of the first dilution section 20 and the second dilution section 50. In other words, the denitrification section 350 is configured to discharge nitrogen compounds in the wastewater as molecular nitrogen to the outside of the float body 2 by denitrification treatment. In this embodiment, the denitrification section 350 includes a first wastewater line 355 and a second wastewater line 356.

[0082] The first discharge liquid line 355 connects the denitrification processing unit 350 to the liquid phase of the first dilution unit 20. An on / off valve (not shown) is provided in the middle of the first discharge liquid line 355, which allows for the intermittent supply of ammonia liquid from the liquid phase of the first dilution unit 20 to the denitrification processing unit 350. The second discharge liquid line 356 connects the denitrification processing unit 350 to the liquid phase of the second dilution unit 50. An on / off valve (not shown) is provided in the middle of the second discharge liquid line 356, which allows for the intermittent supply of ammonia gas from the liquid phase of the second dilution unit 50 to the denitrification processing unit 350.

[0083] The denitrification unit 350 performs denitrification using an appropriate method. For example, the denitrification unit 350 may perform denitrification using, for example, a strongly acidic chemical solution as a reactant. In this embodiment, the denitrification unit 350 performs denitrification using, for example, seawater electrolyte.

[0084] The denitrification unit 350 comprises an electrolysis unit 351 and a denitrification reaction unit 352. The electrolysis unit 351 generates a seawater electrolyte containing sodium hypochlorite by electrolyzing seawater introduced from the outside of the floating body 1 and the surrounding sea. The seawater electrolyte generated in the electrolysis unit 351 is supplied to the denitrification reaction unit 352 through the reactant supply line 353.

[0085] The denitrification reaction unit 352 mixes the ammonia-containing wastewater discharged from at least one of the liquid phases of the first dilution unit 20 and the second dilution unit 50 through the first wastewater line 355 and the second wastewater line 356 with the seawater electrolyte supplied through the reactant supply line 353. The denitrification reaction unit 352 denitrifies the ammonia-containing wastewater by reacting it with the seawater electrolyte. In other words, the denitrification reaction unit 352 converts the ammonia, which is a nitrogen compound contained in the wastewater, and the nitrogen compounds produced in the process of ammonia decomposition into molecular nitrogen.

[0086] The molecular nitrogen produced by the denitrification process in the denitrification reaction unit 352 is exhausted to the outside through the exhaust line 359 connected to the denitrification reaction unit 352, via a funnel 9 (see Figure 1) or a vent post (not shown). Furthermore, the liquid (water or liquid containing dilute components) that has been denitrified by the denitrification reaction unit 352 is discharged to the outside of the denitrification reaction unit 352 through the drainage line 358 connected to the denitrification reaction unit 352. The liquid discharged through the drainage line 358 may, for example, be discharged into the sea outside the floating body 1, reused within the floating body 1, or stored within the floating body 1 and brought ashore. In addition, the liquid (water or liquid containing dilute components) from which nitrogen compounds have been removed by the denitrification treatment in the denitrification reaction unit 352 may be returned to the first dilution unit 20 or the second dilution unit 50 and reused as the first absorbent liquid L1 of the first dilution unit 20 and the second absorbent liquid L2 of the second dilution unit 50.

[0087] (Effects and Benefits) In the third embodiment described above, ammonia water is produced in the ammonia water production unit 310 by mixing the ammonia solution introduced from at least one of the liquid phases of the first dilution unit 20 and the second dilution unit 50 with water. This makes it possible to produce ammonia water from ammonia recovered from ammonia-containing gas, thereby enabling the effective utilization of ammonia.

[0088] Furthermore, in the third embodiment described above, the ammonia water produced in the ammonia water production unit 310 is used as a reducing agent in the denitrification device 320. This allows the denitrification unit 320 to perform denitrification treatment on the exhaust gas discharged from the combustion device, which burns fuel to produce exhaust gas. Nitrogen can be extracted from the exhaust gas, which is a nitrogen compound, and discharged as pure nitrogen. In this way, ammonia recovered from ammonia-containing gas can be effectively utilized.

[0089] In the third embodiment described above, the ammonia water production unit 310 mixes ammonia introduced from at least one of the liquid phase and gas phase of a tank 300 capable of storing ammonia with ammonia liquid and water to produce ammonia water. This makes it possible to easily adjust the ammonia concentration of the produced ammonia water using the ammonia stored in the tank 300.

[0090] In the third embodiment described above, by providing a denitrification treatment unit 350, the wastewater containing ammonia discharged from at least one of the liquid phases of the first dilution unit 20 and the second dilution unit 50 can be denitrified. This makes it possible to discharge nitrogen compounds contained in the wastewater as molecular nitrogen.

[0091] In the third embodiment described above, the denitrification unit 350 reacts a mixture of seawater electrolyte containing sodium hypochlorite and wastewater. This eliminates the need to store a strongly acidic chemical solution for ammonia decomposition. Therefore, it becomes possible to perform denitrification treatment while keeping costs down.

[0092] Furthermore, similar to the first embodiment described above, the ammonia contained in the ammonia-containing gas is efficiently absorbed by sequentially passing through the first dilution section 20 and the second dilution section 50. This enhances the efficiency of ammonia removal.

[0093] (Modified version of the third embodiment) In the third embodiment, the ammonia water was supplied to the denitrification device 320, but the ammonia water is not limited to the denitrification device. The ammonia water may be supplied to a device that can effectively utilize the ammonia water and decompose ammonia into nitrogen, and may be a different type of device than the denitrification device 320. An example of a different type of device that can decompose ammonia into nitrogen is a combination of an ammonia stripping device and a fuel cell.

[0094] (First modified example of the third embodiment) Figure 9 shows the configuration of an ammonia removal system in a first modified example of the third embodiment of the present disclosure. As shown in Figure 9, the ammonia abatement system 100C in the first modified example of the third embodiment further includes, in addition to the configuration of the third embodiment, a shift line 314 that can transfer the second absorbent liquid L2 stored in the second dilution section 50 to the first dilution section 20. According to this first modified example of the third embodiment, the second absorbent liquid L2, which has absorbed ammonia in the second dilution section 50, can be utilized in the first dilution section 20, and the second absorbent liquid L2 in the second dilution section 50 can absorb even more ammonia. This leads to the effective utilization of the second absorbent liquid L2 in the second dilution section 50.

[0095] (Modifications of the first to third embodiments) In the first to third embodiments described above, the ammonia-containing gas can be directly supplied to the second dilution unit 50 via the bypass line 110, without passing through the first dilution unit 20, but the configuration is not limited to this. For example, as shown in the modified example in Figure 10, a bypass line 400 branching off from the gas flow line 10 may be connected to the second discharge line 70. The bypass line 400 is connected to the gas flow line 10 upstream of the on-off valve 15. An on-off valve 410 is provided in the middle of the bypass line 400 to intermittently control the inflow of ammonia-containing gas into the bypass line 400.

[0096] Furthermore, the system may also include a first branch line 401 that branches off from the bypass line 400 and is connected to the second dilution section 50, and a second branch line 402 that is connected to the second discharge line 70. An on-off valve 411 is provided in the middle of the first branch line 401. An on-off valve 412 is provided in the middle of the second branch line 402. By opening and closing the on-off valves 411 and 412, the destination of the ammonia-containing gas flowing into the bypass line 400 when the on-off valve 410 is opened can be appropriately selected from the second dilution section 50 and the second discharge line 70.

[0097] By providing such a bypass line 400, when releasing residual pressure in the gas distribution line 10, etc., the residual gas pressure in the gas distribution line 10 can be quickly released through the bypass line 400. In addition, in the modified example shown in Figure 10, redundancy may be provided by providing multiple bypass lines 400 and on-off valves 410, as in the first modified example of the first embodiment (see Figure 3). Furthermore, in the modified example shown in Figure 10, a single three-way valve may be provided instead of the on-off valves 15 and 410, as in the second modified example of the first embodiment. Also, similarly to the above, an on-off valve may be provided in parallel with the three-way valve to provide redundancy.

[0098] (Other embodiments) Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure.

[0099] <Note> The ammonia removal systems 100A to 100D and the floating body 1 described in each embodiment can be understood, for example, as follows.

[0100] (1) The ammonia removal systems 100A to 100D according to the first embodiment include: a gas flow line 10 through which ammonia-containing gas flows; a first dilution section 20 that absorbs ammonia contained in the ammonia-containing gas supplied from the gas flow line 10 into a first absorbent liquid L1 under pressurized conditions; a first discharge line 30 that can discharge the gas phase gas in the first dilution section 20 as a primary treatment gas G1 to the outside of the first dilution section 20; a second dilution section 50 that absorbs ammonia contained in the primary treatment gas G1 supplied through the first discharge line 30 into a second absorbent liquid L2 at a pressure lower than that of the first dilution section 20; and a control valve 35 provided in the first discharge line 30 that adjusts the supply of the primary treatment gas G1 from the first dilution section 20 to the second dilution section 50.

[0101] In this ammonia abatement system 100A-100D, ammonia contained in the ammonia-containing gas supplied from the gas flow line 10 is absorbed into the first absorbent liquid L1 under pressurized conditions in the first dilution section 20. The gas in the gas phase within the first dilution section 20 is then discharged outside the first dilution section 20 as primary treatment gas G1 through the first discharge line 30. In the second dilution section 50, the ammonia contained in the primary treatment gas G1 is absorbed into the second absorbent liquid L2 under a lower pressure than in the first dilution section 20. This allows the ammonia-containing gas to be retained in the first dilution section 20, enabling batch ammonia abatement. Therefore, ammonia can be abated with a simple system configuration without using absorption towers or other equipment affected by the ship's tilt. Consequently, the efficiency of ammonia abatement can be further increased.

[0102] (2) The ammonia abatement systems 100A to 100D according to the second embodiment are the ammonia abatement systems 100A to 100D of (1), wherein the first dilution section 20 brings the gas phase in the first dilution section 20 and the liquid phase in the first dilution section 20 into a gas-liquid equilibrium state.

[0103] This allows the first absorbent liquid L1 to absorb the maximum amount of ammonia contained in the ammonia-containing gas supplied from the gas flow line 10. Therefore, the ammonia concentration of the gas phase in the first dilution section can be sufficiently reduced before being sent to the second dilution section 50.

[0104] (3) The ammonia abatement systems 100A to 100D according to the third embodiment are the ammonia abatement systems 100A to 100D of (1) or (2), further comprising a control device 60 that controls the opening and closing operation of the control valve 35, wherein the control device 60 transitions the control valve 35 from a closed state to an open state when the ammonia concentration in the gas phase in the first dilution section 20 falls below a specified value.

[0105] As a result, the ammonia-containing gas is sufficiently absorbed into the first absorbent liquid L1 within the first dilution section 20, and the primary treated gas G1, with an ammonia concentration below a specified value, can be supplied to the second dilution section 50. This reduces the load of ammonia absorption in the second dilution section 50.

[0106] (4) The ammonia abatement system 100A to 100D according to the fourth embodiment is any one of the ammonia abatement systems 100A to 100D of (1) to (3), wherein the second dilution unit 50 absorbs the ammonia contained in the primary treatment gas G1 into the second absorbent liquid L2 under atmospheric pressure.

[0107] This allows the second dilution section 50 to have a simple configuration that does not require equipment such as a pump for pressurization.

[0108] (5) The ammonia abatement systems 100A to 100D according to the fifth embodiment are any one of the ammonia abatement systems 100A to 100D of (1) to (4), further comprising a bypass line 110 that bypasses the first dilution section 20 and connects the gas flow line 10 and the first delivery line 30.

[0109] This allows for the rapid release of residual gas pressure in the gas distribution line 10 through the bypass line 110 when releasing residual pressure in the gas distribution line 10.

[0110] (6) The ammonia abatement system 100A to 100D according to the sixth embodiment is any one of the ammonia abatement systems 100A to 100D of (1) to (5), further comprising a second discharge line 70 capable of discharging the gas in the gas phase within the second dilution section 50 as a secondary treatment gas G2 to the outside of the second dilution section 50, and a third dilution section 80 that reduces the concentration of ammonia contained in the secondary treatment gas G2 supplied through the second discharge line 70.

[0111] This allows for a further reduction in the concentration of ammonia contained in the secondary treatment gas G2.

[0112] (7) The ammonia abatement systems 100A to 100D according to the seventh embodiment are any one of the ammonia abatement systems 100A to 100D from (1) to (6), wherein the ammonia-containing gas is a purge gas containing an inert gas.

[0113] This makes it possible to efficiently remove ammonia contained in the purge gas that flows in in large quantities through the gas flow line 10 during purging.

[0114] (8) The ammonia abatement systems 100A to 100D according to the eighth embodiment are any one of the ammonia abatement systems 100A to 100D from (1) to (7), wherein the ammonia-containing gas is boil-off gas produced in a tank capable of storing ammonia.

[0115] This allows the ammonia contained in the boil-off gas generated in a tank capable of storing ammonia to be efficiently removed by the first dilution section 20 and the second dilution section 50.

[0116] (9) The ammonia abatement system 100B according to the ninth embodiment is any one of the ammonia abatement systems 100B from (1) to (8), further comprising a gas suction unit 200 for drawing ammonia-containing gas into the second dilution unit 50 from outside the second dilution unit 50.

[0117] This allows the ammonia contained in the ammonia-containing gas drawn in by the gas suction unit 200 to be absorbed by the second absorbent liquid L2.

[0118] (10) The ammonia abatement system 100B according to the tenth embodiment is the ammonia abatement system 100B of (9), wherein the gas suction unit 200 suctions the ammonia-containing gas flowing through the gas flow line 10B into the second dilution unit 50 from the gas flow line 10B.

[0119] This allows, for example, ammonia-containing gas remaining in the gas flow line 10 to be drawn out by the gas suction unit 200. Therefore, ammonia contained in the ammonia-containing gas remaining in the gas flow line 10 can be absorbed by the second absorbent liquid L2 of the second dilution unit 50. Thus, it becomes possible to further reduce the ammonia concentration in the gas flow line 10.

[0120] (11) An ammonia abatement system 100C according to the eleventh embodiment is any one of the ammonia abatement systems 100C from (1) to (10), further comprising an ammonia water production unit 310 that generates ammonia water by mixing ammonia solution introduced from at least one of the liquid phases of the first dilution unit 20 and the second dilution unit 50 with water.

[0121] This allows for the production of ammonia water from ammonia recovered from ammonia-containing gas, thereby promoting the effective utilization of ammonia.

[0122] (12) The ammonia abatement system 100C according to the twelfth embodiment is the ammonia abatement system 100C of (11), further comprising a denitrification device 320 that denitrifies the exhaust gas discharged from a combustion device 8 that discharges exhaust gas by burning fuel, The ammonia water produced in the ammonia water production unit 310 is used as a reducing agent in the denitrification device 320.

[0123] This allows the exhaust gas emitted from the combustion device 8, which burns fuel and produces exhaust gas, to undergo denitrification treatment. Therefore, the ammonia recovered from the ammonia-containing gas can be effectively utilized.

[0124] (13) An ammonia abatement system 100C according to the 13th embodiment is an ammonia abatement system 100C according to (11) or (12), further comprising a tank 300 capable of storing ammonia, wherein the ammonia water production unit 310 mixes ammonia introduced from at least one of the liquid phase and gas phase of the tank 300 with the ammonia liquid and the water to produce the ammonia water.

[0125] This makes it possible to easily adjust the ammonia concentration of the generated ammonia water using the ammonia stored in tank 300.

[0126] (14) The ammonia abatement system 100C according to the 14th embodiment is the ammonia abatement system 100C of (13), comprising at least one of: a NOx detection unit S1 for detecting the nitrogen oxide concentration of the exhaust gas discharged from the denitrification device 320; and an ammonia detection unit S2 for detecting the ammonia concentration of the exhaust gas discharged from the denitrification device 320. This makes it possible to adjust the amount of ammonia supplied to the denitrification device 320 according to the nitrogen oxide concentration and ammonia concentration of the exhaust gas.

[0127] (15) An ammonia abatement system 100C according to the 15th embodiment is any one of the ammonia abatement systems 100C from (1) to (14), further comprising a denitrification processing unit 350 capable of denitrifying a discharge liquid containing ammonia that is discharged from at least one of the liquid phases of the first dilution unit 20 and the second dilution unit 50.

[0128] This makes it possible to discharge nitrogen compounds contained in the wastewater as molecular nitrogen.

[0129] (16) The ammonia abatement system 100C according to the 16th embodiment is the ammonia abatement system 100C of (15), wherein the denitrification section 350 includes an electrolysis section 351 that generates a seawater electrolyte containing sodium hypochlorite by electrolyzing seawater introduced from an external source, and a denitrification reaction section 352 that reacts the discharge liquid with a mixture of the seawater electrolyte generated in the electrolysis section 351.

[0130] This configuration eliminates the need to store highly acidic chemicals for ammonia decomposition. Therefore, denitrification can be performed while keeping costs down.

[0131] (17) The floating body 1 according to the 17th embodiment comprises a floating body body 2 and one of the ammonia removal systems 100A to 100D from (1) to (16). Examples of floating structures include liquefied gas carriers, ferries, RORO ships, car carriers, passenger ships, and other vessels, as well as FSUs (Floating Storage Units) and FSRUs (Floating Storage and Regasification Units).

[0132] This makes it possible to provide a floating body 1 equipped with ammonia removal systems 100A to 100D that can further improve the efficiency of ammonia removal.

[0133] (18) The ammonia supply method according to the 18th embodiment is an ammonia supply method in the ammonia abatement system 100C of (14), wherein the amount of ammonia water supplied to the denitrification device 320 or the concentration of the ammonia water is adjusted based on at least one of the nitrogen oxide concentration of the exhaust gas discharged from the denitrification device 320 and the ammonia concentration of the exhaust gas discharged from the denitrification device 320. This allows for the supply of an appropriate amount of ammonia to the denitrification device 320. [Explanation of Symbols]

[0134] 1…Floating structure 2…Floating structure body 2a…Bow 4…Superstructure 5A, 5B…Side 6…Bottom 7…Upper deck 8…Combustion device 9…Funnel 10, 10B…Gas flow line 15, 203, 221, 231, 241, 261, 410, 411, 412…On / off valve 20…First dilution section 30…First discharge line 35…Control valve 50…Second dilution section 60…Control device 70…Second discharge line 80…Third dilution section 90…Exhaust line 100A~100D…Ammonia abatement system 110…Bypass line 115…Valve 200…Gas suction section 205…Ejector 207…Liquid supply line 208…Pump 209…Connection line 220…Inlet line 230…Connection line 240…Inert gas inlet line 260…Air intake line 300…Tank 310…Ammonia water production section 311…Ammonia water storage tank 312…First connection line 313…Second connection line 314…Shift line 315…First tank connection line 316…Second tank connection line 320…Denitrification device 321…Reducing agent supply line 325…Exhaust line 350…Denitrification processing section 351…Electrolysis section 352…Denitrification reaction section 353…Reactant supply line 355…First discharge liquid line 356…Second discharge liquid line 358…Drainage line 359…Exhaust line 400…Bypass line 401…First branch line 402…Second branch line 415…Three-way valve G1…Primary treatment gas G2…Secondary treatment gas L1…First absorbent liquid L2…Second absorbent liquid S1…NOx detection section S2…Ammonia detection section

Claims

1. A gas distribution line through which ammonia-containing gas flows, A first dilution unit that absorbs ammonia contained in the ammonia-containing gas supplied from the gas flow line into a first absorbent liquid under pressurized conditions, A first discharge line is provided that can discharge the gas in the gas phase within the first dilution section as a primary treatment gas to the outside of the first dilution section. The first delivery line includes a control valve that adjusts the supply of the primary processing gas from the first dilution section to the outside of the first dilution section. Ammonia removal system.

2. The first dilution section brings the gas phase and the liquid phase within the first dilution section into a gas-liquid equilibrium state. The ammonia removal system according to claim 1.

3. The system further includes a control device for controlling the opening and closing operation of the aforementioned control valve. The control device is When the ammonia concentration in the gas phase within the first dilution section falls below a predetermined value, the control valve is switched from a closed state to an open state. The ammonia removal system according to claim 1 or 2.

4. The ammonia-containing gas is a purge gas containing an inert gas. The ammonia removal system according to claim 1 or 2.

5. The ammonia-containing gas is a boil-off gas produced in a tank capable of storing ammonia. The ammonia removal system according to claim 1 or 2.

6. The system further comprises an ammonia water production unit that generates ammonia water by mixing the ammonia solution introduced from the liquid phase of the first dilution unit with water. The ammonia removal system according to claim 1 or 2.

7. The system further includes a denitrification device that denitrifies the exhaust gas emitted from a combustion device that burns fuel, The ammonia water produced in the ammonia water production unit is used as a reducing agent in the denitrification apparatus. The ammonia removal system according to claim 6.

8. It also has tanks capable of storing ammonia, The ammonia water production unit mixes ammonia introduced from at least one of the liquid phase and gas phase of the tank with the ammonia liquid and the water to produce ammonia water. The ammonia removal system according to claim 6.

9. The system comprises at least one of the following: a NOx detection unit for detecting the nitrogen oxide concentration of the exhaust gas discharged from the denitrification device, and an ammonia detection unit for detecting the ammonia concentration of the exhaust gas discharged from the denitrification device. The ammonia removal system according to claim 7.

10. The system further comprises a denitrification treatment unit capable of denitrifying the discharged liquid containing ammonia, which is discharged from the liquid phase of the first dilution unit. The ammonia removal system according to claim 1 or 2.

11. The aforementioned denitrification treatment unit is The electrolysis unit generates a seawater electrolyte solution containing sodium hypochlorite by electrolyzing seawater introduced from an external source, The unit includes a denitrification reaction unit that reacts the wastewater with a mixture of the seawater electrolyze produced in the electrolysis unit. The ammonia removal system according to claim 10.

12. The floating body and an ammonia removal system according to claim 1 or 2, comprising A floating object.

13. A method for supplying ammonia in an ammonia decontamination system according to claim 9, Based on at least one of the nitrogen oxide concentration of the exhaust gas discharged from the denitrification device and the ammonia concentration of the exhaust gas discharged from the denitrification device, the amount of ammonia water supplied to the denitrification device or the concentration of the ammonia water is adjusted. Ammonia supply method.

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