Ammonia-detoxifying system

Abstract

This ammonia-detoxifying system is provided with a first dilution treatment device comprising: a first tank that retains an absorption liquid capable of absorbing ammonia; a gas introduction unit that introduces, into the first tank, an ammonia-containing gas to be detoxified; a bubble generation unit that generates bubbles in the absorption liquid by using the gas to be detoxified introduced by the gas introduction unit to generate, in the absorption liquid, a rising flow generated due to rise of the bubbles; a bubble micronization unit that is provided above the bubble generation unit and micronizes the bubbles; and a first gas discharge line that discharges a gas from a gas phase in the first tank to the outside of the first tank.

Description

Ammonia removal system

[0001] This disclosure relates to an ammonia abatement system. This application claims priority to Japanese Patent Application No. 2024-070826, filed on April 24, 2024, the contents of which are incorporated herein by reference.

[0002] Ammonia leakage is possible in ships that use ammonia as fuel for their main engines, devices, facilities, etc. that handle ammonia. Furthermore, in such ships that use ammonia, devices, facilities, etc. that handle ammonia, purging with an inert gas that does not react with ammonia may be performed, and the remaining ammonia may be discharged along with the inert gas. Because ammonia may act on human mucous membranes and cause damage, ammonia-containing gas generated by the above-mentioned leakage or purging cannot be directly released into the atmosphere. Patent Document 1 discloses a configuration in which ammonia is introduced into an absorption liquid stored in an absorption tank, and then the gas phase in the tank is released to the atmosphere. In this configuration, ammonia is introduced into the absorption liquid stored in the absorption tank, causing the ammonia component to be absorbed into the absorption liquid.

[0003] Japanese Patent Application Laid-Open No. 2023-34573

[0004] In the configuration in which ammonia is absorbed in an absorbing solution as described in Patent Document 1, there is a possibility that ammonia will not be sufficiently absorbed by the absorbing solution and will remain in the gas phase due to various factors. However, in order to prevent ammonia from remaining in the gas phase, it is necessary to increase the amount of absorbing solution or to increase the size of the device.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an ammonia detoxification system that can efficiently absorb ammonia into an absorption liquid while suppressing an increase in the amount of absorption liquid or an increase in the size of the device.

[0006] In order to solve the above problems, the ammonia detoxification system according to the present disclosure includes a first dilution treatment device. The first dilution treatment device includes a first tank, a gas inlet, a bubble generator, a bubble atomization unit, and a first gas delivery line. The first tank stores an absorption liquid capable of absorbing ammonia. The gas inlet introduces the ammonia-containing gas to be abatement into the first tank. The bubble generator generates bubbles within the absorption liquid using the gas to be abatement introduced by the gas inlet, and generates an upward flow in the absorption liquid as the bubbles rise. The bubble atomization unit is provided above the bubble generator and atomizes the bubbles. The first gas delivery line delivers gas from the gas phase within the first tank to the outside of the first tank.

[0007] According to the ammonia detoxification system of the present disclosure, it is possible to efficiently absorb ammonia into the absorbing solution while suppressing an increase in the amount of absorbing solution and an increase in the size of the device.

[0008] Fig. 1 is a diagram showing the configuration of an ammonia detoxification system according to a first embodiment of the present disclosure. Fig. 2 is a cross-sectional view showing the configuration of a bubble generation unit and a bubble micronization unit of the ammonia detoxification system according to the first embodiment of the present disclosure. Fig. 3 is a diagram showing the configuration of an ammonia detoxification system according to a second embodiment of the present disclosure. Fig. 4 is a diagram showing the configuration of an ammonia detoxification system according to a modified example of the second embodiment of the present disclosure.

[0009] First Embodiment An ammonia detoxification system according to an embodiment of the present disclosure will now be described with reference to FIGS. 1 to 4. (Configuration of the Ammonia Detoxification System) As shown in FIG. 1, the ammonia detoxification system 100A of this first embodiment includes a first dilution treatment device 20, a second dilution treatment device 30, and a third dilution treatment device 40. The ammonia detoxification system 100A removes and detoxifies ammonia contained in a gas G to be detoxified, which is introduced through a gas introduction section 10. The ammonia detoxification system 100A is installed in a ship that uses ammonia as fuel for the main engine, or in equipment, facilities, etc. that handle ammonia. The ammonia detoxification system 100A purges ammonia-containing gas leaked from such a ship, equipment, facility, etc., or ammonia-containing gas discharged together with the inert gas using an inert gas that does not react with ammonia, and treats the ammonia-containing gas, etc., as the gas G to be detoxified.

[0010] The gas introduction section 10 is equipped with a purge gas introduction line 11. The purge gas introduction line 11 is connected to a piping system including, for example, a fuel system of a combustion device. The combustion device is a device that generates thermal energy by burning ammonia as fuel, and is provided, for example, on a floating body (not shown). Examples of the combustion device include an internal combustion engine used as a main engine for propelling the floating body, an internal combustion engine used in a power generation facility that supplies electricity to the inside of the floating body, and a boiler that generates steam as a working fluid.

[0011] When switching the fuel for a combustion apparatus from ammonia to another fuel or when performing maintenance, ammonia remaining in a piping system including the fuel system of the combustion apparatus is replaced with an inert gas (purge gas) such as nitrogen, a process known as purging. Here, the ammonia remaining in the piping system may be liquefied ammonia or ammonia gas. To perform purging, 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 may be any gas that does not chemically react when in contact with ammonia, such as nitrogen. When the inert gas supply device supplies an inert gas 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.

[0012] One end of the purge gas introduction line 11 is connected to a piping system of a combustion apparatus (not shown), etc. Purge gas discharged from the piping system of the combustion apparatus during purging is introduced into the purge gas introduction line 11 as the gas to be abatement G. The other end of the purge gas introduction line 11 is connected to a first dilution treatment device 20. An on-off valve 11v is provided in the purge gas introduction line 11, and the introduction of the gas to be abatement G into the first dilution treatment device 20 is turned on and off by opening and closing the on-off valve 11v.

[0013] The first dilution treatment device 20 includes a first tank 21, a gas introduction line 22, a bubble generation unit 23, a bubble atomization unit 24, and a first gas delivery line 25. The first tank 21 stores therein an absorption liquid L capable of absorbing ammonia. Fresh water or seawater is stored in the first tank 21 as the absorption liquid L. As a result, the absorption liquid L is stored in the lower part of the first tank 21. The first tank 21 may be provided with a heat exchanger (not shown) for adjusting the temperature of the absorption liquid L.

[0014] The gas introduction line 22 introduces the target gas G to be abatement into the first tank 21. The gas introduction line 22 is tubular and connected to the purge gas introduction line 11. In this embodiment, the gas introduction line 22 extends from above to below within the first tank 21.

[0015] FIG. 2 is a cross-sectional view showing the configuration of the bubble generating unit and the bubble atomizing unit of the ammonia detoxification system according to the first embodiment of the present disclosure. As shown in FIGS. 1 and 2 , the bubble generating unit 23 is connected to the gas introduction line 22. In this first embodiment, a plurality of bubble generating units 23 are provided, and each of these bubble generating units 23 is connected to the gas introduction line 22. In this first embodiment, the plurality of bubble generating units 23 are all disposed in the lower portion of the first tank 21. In this first embodiment, each bubble generating unit 23 has a cylindrical shape extending vertically. In this embodiment, the lower end of the bubble generating unit 23 is connected to the gas introduction line 22. The bubble generating unit 23 injects the target gas G to be ablated, introduced via the gas introduction line 22, into the absorption liquid L and also in an upward direction. The injection by the bubble generating unit 23 generates bubbles B in the absorption liquid L. The bubbles B then rise within the absorption liquid L. As the bubbles B rise, an upward flow F of the absorbing liquid L is generated around the bubble generating section 23 .

[0016] The bubble atomizing section 24 is provided above the bubble generating section 23. The bubble atomizing section 24 atomizes the bubbles B generated by the bubble generating section 23. Here, atomization means dividing the bubbles B generated by the bubble generating section 23 into a plurality of bubbles B that are smaller than the bubbles B generated by the bubble generating section 23. The bubble atomizing section 24 in this embodiment has, for example, a tube body 24p and blade sections 24w.

[0017] The pipe 24p exemplified in this embodiment extends in the vertical direction. The inner diameter of the pipe 24p is larger than the outer diameter of the bubble generation section 23. The upper end of the bubble generation section 23 is inserted into the lower end of the pipe 24p from below. A plurality of openings 24h are formed at the lower end of the pipe 24p. The absorption liquid L in the first tank 21 is introduced into the pipe 24p through these plurality of openings 24h. An upward flow F of the absorption liquid L caused by the bubble generation section 23 is generated in the pipe 24p. Due to the upward flow F of the absorption liquid L generated in the pipe 24p, the absorption liquid L in the first tank 21 is sequentially introduced into the pipe 24p through the openings 24h.

[0018] The wing portion 24w is provided at the upper end of the pipe 24p. The wing portion 24w is fixed inside the pipe 24p. The wing portion 24w turbulently agitates the upward flow F rising inside the pipe 24p. The wing portion 24w illustrated in this embodiment is spiral-shaped and has multiple through-holes (not shown). The upward flow F rising inside the pipe 24p becomes a swirling flow that swirls upward due to the wing portion 24w. The bubbles B contained in the upward flow F are refined by passing through the swirling flow and the multiple through-holes formed in the wing portion 24w or by coming into contact with the inner edges of the through-holes. Note that, in order to refine the bubbles B, multiple protrusions may be provided on the surface of the wing portion 24w.

[0019] The bubbles B atomized by the bubble atomization unit 24 rise in the absorption liquid L in the first tank 21 and reach the liquid surface, i.e., the upper gas phase, in the first tank 21. As the atomized bubbles B rise, they come into contact with the absorption liquid L, and a portion of the ammonia component contained in the abatement target gas G that forms the bubbles B is absorbed into the absorption liquid L. As shown in FIG. 2 , the absorption liquid L flows upward due to the ascending flow F ejected from the bubble atomization unit 24, and then changes direction of flow downward while spreading outward near the liquid surface in the first tank 21. The absorption liquid L that reaches the bottom of the first tank 21 is again sucked into the pipe body 24p through the opening 24h. In this way, the absorption liquid L circulates within the first tank 21. At least a portion of the bubbles B atomized by the bubble atomization unit 24 circulates within the first tank 21 together with the absorption liquid L, thereby increasing the contact time with the absorption liquid L and increasing the absorption efficiency of the ammonia component into the absorption liquid L. As a result, the liquid in the liquid phase in the first tank 21 contains the absorption liquid L and the ammonia component. In addition, the gas A forming the gas phase above the liquid phase in the first tank 21 contains the ammonia component that has not been completely absorbed by the absorption liquid L and remains.

[0020] 1 , the first gas delivery line 25 delivers the gas A from the gas phase in the first tank 21 to the outside of the first tank 21. In this embodiment, the first gas delivery line 25 is connected to the second tank 31 of the second dilution treatment device 30.

[0021] The second dilution treatment device 30 is provided downstream of the ammonia detoxification process in the ammonia detoxification system 100A with respect to the first dilution treatment device 20. The second dilution treatment device 30 includes a second tank 31, an absorption promoter 32, and a second gas delivery line 35.

[0022] The second tank 31 stores therein an absorption liquid L capable of absorbing ammonia. Fresh water or seawater is stored in this second tank 31 as the absorption liquid L. As a result, the absorption liquid L is stored in the lower part of the second tank 31. Gas A from the first gas delivery line 25 is introduced into the gas phase in the second tank 31. The gas A delivered from the first gas delivery line 25 is temporarily stored in the second tank 31.

[0023] The absorption promoter 32 promotes the absorption of ammonia by the absorption liquid L in the second tank 31. The absorption promoter 32 in this embodiment includes a circulation line 33, a spray unit 34, a circulation pump 33p, and a heat exchanger 33h.

[0024] One end of the circulation line 33 is connected to the lower part of the second tank 31. The other end of the circulation line 33 is disposed in the gas phase at the upper part of the second tank 31. A spray unit 34 is provided at the other end of the circulation line 33 within the second tank 31. A circulation pump 33p and a heat exchanger 33h are provided midway along the circulation line 33. The circulation pump 33p draws the liquid-phase absorption liquid L in the second tank 31 into the circulation line 33 and circulates it to the gas phase at the upper part of the second tank 31. The heat exchanger 33h cools the liquid phase drawn into the circulation line 33 and removes the heat of reaction generated when ammonia dissolves in the absorption liquid L. The spray unit 34 can spray the absorption liquid L, which is supplied from outside the second tank 31 through the circulation line 33, from the upper part of the second tank 31. This allows the absorption liquid L contained in the liquid phase to come into contact with the ammonia component contained in the gas A in the gas phase within the second tank 31, thereby promoting the absorption of ammonia.

[0025] The second gas delivery line 35 delivers the gas A from the upper portion of the second tank 31 to the outside of the second tank 31. In the embodiment of the present disclosure, the second gas delivery line 35 delivers the gas A to a third dilution treatment device 40.

[0026] A first valve 37 is provided on the first gas delivery line 25 connected to the second tank 31. The first valve 37 opens and closes the flow path of gas A from the first gas delivery line 25 to the second tank 31. The first valve 37 opens and closes the flow path of the first gas delivery line 25. Opening and closing the first valve 37 enables and disables the introduction of gas A into the second tank 31 through the first gas delivery line 25. A second valve 38 is provided on the second gas delivery line 35. The second valve 38 opens and closes the flow path of gas A from the second tank 31 to the second gas delivery line 35. The second valve 38 is provided midway along the second gas delivery line 35. Opening and closing the second valve 38 opens and closes the flow path in the second gas delivery line 35. Opening and closing the second valve 38 enables and disables the outflow of gas A from the second tank 31 to the second gas delivery line 35.

[0027] In the second dilution treatment device 30, for example, the first valve 37 is opened, and gas A from the first tank 21 is introduced into the second tank 31 through the first gas delivery line 25. Then, the first valve 37 and the second valve 38 are closed to absorb the ammonia contained in the gas A. With the first valve 37 and the second valve 38 closed, the gas A is continuously brought into contact with the absorption liquid L circulating in the second tank 31 through the circulation line 33, thereby efficiently absorbing the ammonia. At this time, with the first valve 37 and the second valve 38 closed, for example, after a predetermined time has elapsed, the second valve 38 may be opened to deliver the gas A from the second tank 31 to the third dilution treatment device 40. Furthermore, for example, the pressure in the second tank 31 may be detected by a pressure sensor 39 provided in the second tank 31, and when the detected pressure exceeds a predetermined reference pressure, the second valve 38 may be opened to release the pressure in the second tank 31 to the third tank 41.

[0028] The third dilution treatment device 40 is provided downstream of the ammonia detoxification process in the ammonia detoxification system 100A with respect to the first dilution treatment device 20 and the second dilution treatment device 30. The third dilution treatment device 40 includes a third tank 41, an introduction section 42, and a third gas delivery line 45.

[0029] The third tank 41 stores therein an absorption liquid L capable of absorbing ammonia. Fresh water or seawater is stored in the third tank 41 as the absorption liquid L. As a result, the absorption liquid L is stored in the lower part of the third tank 41.

[0030] The introduction section 42 introduces the gas A delivered from the second gas delivery line 35 into the absorption liquid L from the lower part of the third tank 41. The introduction section 42 of this embodiment introduces the gas A delivered from the second gas delivery line 35 into the absorption liquid L from the lower part of the third tank 41 via the ejector 43. The ejector 43 is connected to a suction pipe 43p that sucks the absorption liquid L from the lower part of the third tank 41 by a pump 44, the second gas delivery line 35, and the introduction section 42. The ejector 43 discharges the absorption liquid L introduced into the ejector 43 from the suction pipe 43p toward the introduction section 42. As a result, a negative pressure is generated in the ejector 43 by the absorption liquid L flowing from the suction pipe 43p toward the introduction section 42. The ejector 43 sucks the gas A from the second gas delivery line 35 by the generated negative pressure. The ejector 43 mixes the gas A sucked from the second gas delivery line 35 with the absorption liquid L introduced from the suction pipe 43p. As a result, the ejector 43 discharges a mixed fluid in which the gas A and the absorption liquid L are mixed into the liquid phase of the third tank 41 through the introduction part 42. At this time, the flow rate of the gas A sent into the third tank 41 through the second gas delivery line 35 may be adjusted by adjusting the aperture of the second valve 38.

[0031] The third tank 41 is also provided with an introduction part 46 that introduces the gas A delivered from the first gas delivery line 25 into the absorption liquid L from the lower part of the third tank 41. A switching valve 46v is provided in the middle of the introduction part 46. One end of the introduction part 46 is connected to the middle of the first gas delivery line 25. The other end of the introduction part 46 is disposed in the absorption liquid L at the lower part of the third tank 41. The other end of the introduction part 46 is provided with a plurality of discharge holes (not shown) that discharge the gas A in the introduction part 46 into the absorption liquid L. When the first valve 37 is closed and the switching valve 46v is opened, the gas A in the first tank 21 delivered from the first gas delivery line 25 is discharged from the lower part of the third tank 41 into the absorption liquid L through the introduction part 46.

[0032] The gas A discharged from the introduction parts 42, 46 into the absorbing liquid L becomes bubbles B, which rise in the absorbing liquid L. As a result, the ammonia component contained in the gas A is absorbed into the absorbing liquid L.

[0033] The third gas delivery line 45 delivers gas A from the upper part of the third tank 41 to the outside of the third tank 41. The third gas delivery line 45 is capable of discharging gas A from the gas phase inside the third tank 41. One end of the third gas delivery line 45 is connected to the upper part of the third tank 41. The other end of the third gas delivery line 45 is connected to an atmosphere release line 50. The atmosphere release line 50 releases gas A from the upper part of the third tank 41 to the atmosphere via a vent post, vent duct, or funnel provided on the upper deck of the float, for example.

[0034] A dilution line 51 is connected to the atmosphere vent line 50. The dilution line 51 is capable of introducing dilution gas into the atmosphere vent line 50 to reduce the ammonia concentration of the gas A discharged through the atmosphere vent line 50. An example of the dilution gas is outside air (air) taken in from the outside through the dilution line 51. The dilution line 51 is provided with a fan (not shown) capable of adjusting the flow rate of the dilution gas sent into the atmosphere vent line 50.

[0035] A first liquid discharge line 61 is connected to the first tank 21. An on-off valve 61v is provided in the first liquid discharge line 61. The first liquid discharge line 61 is capable of discharging the absorption liquid L from the liquid phase of the first tank 21 by opening the on-off valve 61v. A second liquid discharge line 62 is connected to the second tank 31. An on-off valve 62v is provided in the second liquid discharge line 62. The second liquid discharge line 62 is capable of discharging the absorption liquid L from the liquid phase of the second tank 31 by opening the on-off valve 62v. A third liquid discharge line 63 is connected to the third tank 41. An on-off valve 63v is provided in the third liquid discharge line 63. The third liquid discharge line 63 is capable of discharging the absorption liquid L from the liquid phase of the third tank 41 by opening the on-off valve 63v.

[0036] The first liquid discharge line 61, the second liquid discharge line 62, and the third liquid discharge line 63 are connected to a drain line 60. The drain line 60 is connected to a waste liquid tank (not shown). By operating a pump (not shown) or the like provided in the drain line 60 with the on-off valves 61v, 62v, and 63v open, the absorption liquid in the first tank 21, the second tank 31, and the third tank 41 is discharged from the first liquid discharge line 61, the second liquid discharge line 62, and the third liquid discharge line 63 and collected in the waste liquid tank through the drain line 60.

[0037] In addition, an absorption liquid reuse line 70 branching off from the middle of the drainage line 60 is connected to the second tank 31. An on-off valve 71 is provided on the absorption liquid reuse line 70. By opening the on-off valve 71 while closing the on-off valves 61v and 62v and opening the on-off valve 63v, the absorption liquid reuse line 70 can send the absorption liquid L in the third tank 41, which has a lower ammonia concentration than those in the first tank 21 and the second tank 31, into the second tank 31 and reuse it.

[0038] (Effects) In the ammonia detoxification system 100A of the above embodiment, when the gas G to be detoxified is introduced into the first tank 21 via the gas inlet line 22, bubbles B are generated in the absorption solution L in the bubble generation unit 23. The bubbles B rise in the absorption solution L, generating an upward flow F in the absorption solution L. The bubbles B contained in the upward flow F are atomized by the bubble atomization unit 24 provided above the bubble generation unit 23. This makes it easier for the ammonia contained in the bubbles B to be absorbed into the absorption solution L. Furthermore, since the upward flow F circulates the absorption solution L from the top to the bottom within the first tank 21, at least a portion of the bubbles B atomized by the bubble atomization unit 24 circulates within the first tank 21 together with the absorption solution L. This extends the contact time between the bubbles B and the absorption solution L, thereby increasing the efficiency with which the ammonia contained in the bubbles B is absorbed into the absorption solution L. Therefore, it is possible to efficiently absorb ammonia into the absorption solution L while suppressing an increase in the amount of absorption solution L and an increase in the size of the apparatus. Furthermore, if the target gas G to be removed is pumped through the gas introduction line 22, the ascending flow F can be generated without using a driving source such as a pump. Therefore, if the first dilution treatment device 20 is used alone, it is possible to perform the ammonia absorption treatment even during a power outage, etc. Furthermore, if the target gas G to be removed is pumped through the gas introduction line 22, the pressure inside the first tank 21 becomes higher than atmospheric pressure, and the absorption liquid L is pressurized. As a result, the bubbles B in the first tank 21 are compressed and reduced in diameter, increasing their specific surface area, thereby more effectively absorbing the ammonia contained in the bubbles B into the absorption liquid L. Furthermore, if the target gas G to be removed contains an inert gas, bubbles B are generated in the first tank 21 even when the target gas G contains only a small amount of ammonia, making it easier to generate the ascending flow F in the absorption liquid L and a circulating flow due to the ascending flow F.

[0039] Furthermore, in the above embodiment, the ammonia component contained in the gas A delivered from the first gas delivery line 25 of the first dilution treatment device 20 can be absorbed by the absorption liquid L stored in the second tank 31 of the second dilution treatment device 30. The second dilution treatment device 30 is provided with the absorption promoter 32, so that the absorption of ammonia by the absorption liquid L in the second tank 31 can be carried out efficiently. In this way, by passing the gas G through the first dilution treatment device 20 and the second dilution treatment device 30 in sequence, the ammonia component contained in the abatement target gas G can be more effectively absorbed.

[0040] Moreover, in the above embodiment, the sprayer 34 sprays the absorbing liquid L, which is supplied from outside the second tank 31, from the upper part of the second tank 31. As a result, the absorbing liquid L comes into contact with the gas A delivered from the first gas delivery line 25, and the ammonia component contained in the gas A is absorbed by the absorbing liquid L. The absorbing liquid L that has absorbed the ammonia is circulated to the sprayer 34 through the circulation line 33. As a result, by repeatedly spraying the absorbing liquid L from the upper part of the second tank 31 while circulating the absorbing liquid L in the second tank 31, the contact time between the gas A and the absorbing liquid L can be extended, and the ammonia component contained in the gas A can be sufficiently absorbed. Therefore, there is no need to increase the amount of the absorbing liquid L or the capacity of the second tank 31.

[0041] Furthermore, in the above embodiment, the inflow of gas A from the first gas delivery line 25 into the second tank 31 can be interrupted by opening and closing the first valve 37. Furthermore, the outflow of gas A from the second tank 31 to the second gas delivery line 35 can be interrupted by opening and closing the second valve 38. With the first valve 37 and the second valve 38 closed, the gas A containing ammonia can be continuously brought into contact with the absorption liquid L circulating in the second tank 31. Therefore, ammonia can be sufficiently removed from the gas A containing an ammonia component.

[0042] Furthermore, in the above embodiment, ammonia contained in the gas A delivered from the first gas delivery line 25 of the first dilution treatment device 20 or the second gas delivery line 35 of the second tank 31 can be absorbed by the absorption liquid L stored in the third tank 41 of the third dilution treatment device 40. In this way, ammonia can be more effectively absorbed from the gas A that has passed through the first dilution treatment device 20, or the first dilution treatment device 20 and the second dilution treatment device 30.

[0043] Furthermore, in the above embodiment, the blades 24w cause the upward flow F rising inside the pipe 24p of the bubble atomization section 24 to become a swirling flow. This makes it possible to atomize the bubbles B generated inside the absorption liquid L by the gas G to be abatement. Moreover, because the blades 24w are fixed inside the pipe 24p, loss of the gas G to be abatement when it flows through the compressed gas flow path 24r is reduced compared to when a porous body for atomizing the bubbles B is provided inside the pipe 24p. Furthermore, because the blades 24w are fixed, damage to the blades 24w is also reduced.

[0044] Second Embodiment Next, a second embodiment of an ammonia detoxification system according to the present disclosure will be described. The second embodiment described below differs from the first embodiment only in that it includes a fourth dilution treatment device 80. Therefore, FIG. 2 will be used, and the same components as those in the first embodiment will be denoted by the same reference numerals, and redundant description will be omitted. FIG. 3 is a diagram showing the configuration of an ammonia detoxification system according to the second embodiment of the present disclosure. As shown in FIG. 3, an ammonia detoxification system 100B according to the second embodiment includes a first dilution treatment device 20, a second dilution treatment device 30, a third dilution treatment device 40, and a fourth dilution treatment device (first dilution treatment device) 80.

[0045] The fourth dilution treatment device 80 is provided upstream of the ammonia detoxification process in the ammonia detoxification system 100B with respect to the third dilution treatment device 40. The fourth dilution treatment device 80 includes a first tank 81, a gas introduction line 82, a bubble generation unit 23, a bubble atomization unit 24, and a first gas delivery line 85.

[0046] The first tank 81 stores therein an absorption liquid L capable of absorbing ammonia. The gas introduction line 82 of this embodiment is tubular and connected to the first gas delivery line 25 of the first dilution treatment device 20. The gas introduction line 82 introduces gas-phase gas A from the first tank 21 of the first dilution treatment device 20 into the first tank 81 as the gas G to be abatement. The gas introduction line 82 of this embodiment extends from above to below within the first tank 81. A switching valve 82v is provided in the gas introduction line 82.

[0047] The bubble generating unit 23 is connected to the gas introduction line 82. In this second embodiment, a plurality of bubble generating units 23 are provided, and these plurality of bubble generating units 23 are each connected to the gas introduction line 82. The bubble generating unit 23 sprays the gas A (gas G to be abatement) introduced through the gas introduction line 82 upward into the absorption liquid L. As shown in FIG. 2 , the spraying from the bubble generating unit 23 generates bubbles B in the absorption liquid L, and as the bubbles B rise, an upward flow F of the absorption liquid L is generated around the bubble generating unit 23. The bubble atomizing unit 24 is provided above the bubble generating unit 23. The bubble atomizing unit 24 atomizes the bubbles B generated in the bubble generating unit 23.

[0048] The bubbles B atomized by the bubble atomization unit 24 rise in the absorption liquid L in the first tank 81 and reach the liquid surface in the first tank 81, i.e., the upper gas phase. As the atomized bubbles B come into contact with the absorption liquid L during the process of rising, some of the ammonia components contained in the gas A forming the bubbles B are absorbed into the absorption liquid L. After flowing upward due to the ascending flow F ejected from the bubble atomization unit 24, the absorption liquid L changes direction toward downward while spreading outward near the liquid surface in the first tank 81. The absorption liquid L that has reached the bottom of the first tank 81 is again sucked into the pipe body 24p through the opening 24h. In this way, the absorption liquid L circulates within the first tank 81. At least some of the bubbles B atomized by the bubble atomization unit 24 circulate within the first tank 81 together with the absorption liquid L, thereby increasing the contact time with the absorption liquid L and increasing the efficiency of absorption of the ammonia components into the absorption liquid L. As a result, the liquid in the liquid phase in the first tank 81 contains the absorption liquid L and the ammonia component. In addition, the gas A forming the gas phase above the liquid phase in the first tank 81 contains the ammonia component that has not been completely absorbed by the absorption liquid L and remains.

[0049] The first gas delivery line 85 delivers the gas A from the gas phase in the first tank 81 to the outside of the first tank 81. The first gas delivery line 85 in this embodiment is connected to the introduction part 46 of the fourth dilution treatment device 80. In addition, a branch line 72 branching off from the absorption liquid reuse line 70 is connected to the first tank 81. An on-off valve 73 is provided on the branch line 72. By closing the on-off valves 61v and 62v and opening the on-off valve 73 with the on-off valve 63v open, the branch line 72 can send the absorption liquid L with a low ammonia concentration in the third tank 41 into the first tank 81 for reuse.

[0050] In this fourth dilution treatment device 80, for example, while the second dilution treatment device 30 is performing a process of absorbing the ammonia component contained in the gas A into the absorption liquid L in the second tank 31 with the first valve 37 and the second valve 38 closed, the switching valve 82v is opened so that the gas phase gas A in the first tank 21 of the first dilution treatment device 20 is introduced into the fourth dilution treatment device 80 through the gas introduction line 82. The gas A introduced into the first tank 81 passes through the bubble generation unit 23 and the bubble atomization unit 24, generating bubbles B in the absorption liquid L, and the ammonia component contained in the bubbles B is absorbed into the absorption liquid L. In this way, by performing an absorption process of the ammonia component in the fourth dilution treatment device 80 during the process in the second dilution treatment device 30, it is possible to suppress a pressure increase in the purge gas introduction line 11 and in the first tank 21 of the first dilution treatment device 20.

[0051] (Action and Effect) In the ammonia detoxification system 100B of the second embodiment, as in the first embodiment, when the gas G to be detoxified is introduced into the first tank 21, 81 via the gas introduction line 22, 82, bubbles B are generated inside the absorption liquid L in the bubble generation section 23. These bubbles B rise in the absorption liquid L, generating an upward flow F in the absorption liquid L. The bubbles B contained in the upward flow F are atomized by the bubble atomization section 24 provided above the bubble generation section 23. This makes it easier for the ammonia contained in the bubbles B to be absorbed into the absorption liquid L.

[0052] Furthermore, because the upward flow F circulates the absorption liquid L from the top to the bottom within the first tank 21, 81, at least a portion of the bubbles B atomized by the bubble atomization section 24 circulates within the first tank 21, 81 together with the absorption liquid L. This lengthens the contact time between the bubbles B and the absorption liquid L, and improves the efficiency with which the ammonia contained in the bubbles B is absorbed into the absorption liquid L. Therefore, it is possible to efficiently absorb ammonia into the absorption liquid L while suppressing an increase in the amount of absorption liquid L or an increase in the size of the apparatus.

[0053] (Modification of Second Embodiment) Fig. 4 is a diagram showing the configuration of an ammonia detoxification system according to a modification of the second embodiment of the present disclosure. As shown in Fig. 4, an ammonia detoxification system 100C according to this modification of the second embodiment includes a concentration meter 91, introduction lines 92 and 93, a flow rate adjustment unit 95, and an oil recovery unit 98 in addition to the configuration of the ammonia detoxification system 100B according to the second embodiment.

[0054] The concentration meter 91 is provided in the first gas delivery line 25. The concentration meter 91 detects the ammonia concentration in the gas phase in the first tank 21.

[0055] The inlet line 92 introduces an inert gas or air not containing ammonia from the outside into the absorption solution L in the first tank 21 of the first dilution treatment device 20. An on-off valve 92v is provided in the middle of the inlet line 92. The on-off valve 92v opens and closes the flow path in the inlet line 92. When the ammonia concentration detected by the concentration meter 91 is equal to or higher than a preset reference value, the on-off valve 92v is opened, and the inert gas or air not containing ammonia is introduced into the absorption solution L in the first tank 21 through the inlet line 92. At this time, the on-off valve 11v provided in the purge gas inlet line 11 is closed. This makes it possible to reduce the ammonia concentration in the absorption solution L in the first tank 21. Therefore, the ammonia absorption performance of the absorption solution L is improved, and the ammonia absorption efficiency in the first dilution treatment device 20 can be increased.

[0056] The inlet line 93 introduces an inert gas or air not containing ammonia from the outside into the absorption solution L in the first tank 81 of the fourth dilution treatment device 80. An on-off valve 93v is provided in the inlet line 93. The on-off valve 93v opens and closes the flow path in the inlet line 93. When the ammonia concentration detected by the concentration meter 91 is equal to or higher than a preset reference value, the on-off valve 93v is opened, and the inert gas or air not containing ammonia is introduced into the absorption solution L in the first tank 81 through the inlet line 93. At this time, the on-off valve 11v provided in the purge gas inlet line 11 is closed. This reduces the ammonia concentration in the absorption solution L in the first tank 81. Therefore, the ammonia absorption performance of the absorption solution L is improved, and the ammonia absorption efficiency in the first dilution treatment device 20 can be increased.

[0057] The flow rate adjusting unit 95 is a flow rate adjusting valve provided midway along the purge gas introduction line 11. The flow rate adjusting unit 95 is capable of adjusting the flow rate of the purge gas introduced into the first tank 21 through the purge gas introduction line 11 based on the ammonia concentration detected by the concentration meter 91. In this way, by adjusting the flow rate of the purge gas introduced into the first tank 21 based on the ammonia concentration in the gas phase within the first tank 21, an excessive increase in the ammonia concentration in the gas A delivered from the first tank 21 can be prevented.

[0058] The oil recovery unit 98 sucks out the liquid on the surface of the liquid phase in the first tank 21 to the outside of the first tank 21. If the purge gas introduction line 11 is part of a piping system that includes the fuel system of the combustion device, oil such as lubricating oil used in the combustion device may become mixed into the gas G to be abatemented. In this case, the oil introduced into the first tank 21 through the purge gas introduction line 11 together with the gas G to be abatemented may accumulate on the surface of the liquid phase in the first tank 21. By using the oil recovery unit 98 to suck out the liquid on the surface of the liquid phase in the first tank 21 to the outside of the first tank 21, contamination of the absorption liquid L can be suppressed.

[0059] In the modified example of the second embodiment described above, the concentration meter 91 is used to detect the ammonia concentration in the gas phase within the first tank 21. However, instead of the concentration meter 91, the ammonia concentration in the liquid phase within the first tank 21 may be detected. Furthermore, a flow rate adjustment valve is provided as the flow rate adjustment unit 95 to adjust the flow rate of the purge gas introduced into the first tank 21 through the purge gas introduction line 11. However, this is not limiting. For example, the flow rate of the purge gas sent from a piping system including a fuel system of the combustion device may be adjusted. Furthermore, the purge gas introduction line 11 may be provided with an orifice or the like to limit the flow rate of the purge gas introduced into the first tank 21.

[0060] Other Embodiments While the embodiments of the present disclosure have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design modifications within the scope of the present disclosure. For example, in the second embodiment described above, the first dilution treatment device 20, the second dilution treatment device 30, the third dilution treatment device 40, and the fourth dilution treatment device 80 are provided, but this is not limited thereto. For example, the first dilution treatment device 20 may be omitted, and the second dilution treatment device 30, the third dilution treatment device 40, and the fourth dilution treatment device 80 may be provided.

[0061] Furthermore, although the second dilution treatment device 30 is illustrated as including the dispersion unit 34, the present invention is not limited to this. For example, the second dilution treatment device 30 may be configured similarly to the first dilution treatment device 20. Furthermore, in each of the above embodiments, the second dilution treatment device 30 and the third dilution treatment device 40 may also be configured similarly to the first dilution treatment device 20, including the bubble generation unit 23 and the bubble atomization unit 24. If both the second dilution treatment device 30 and the third dilution treatment device 40 have the same configuration as the first dilution treatment device 20, power for driving multiple dilution treatment devices is not required, and ammonia treatment can be performed even during a power outage, etc.

[0062] Furthermore, in each of the above embodiments, the gas A is introduced into the third tank 41 of the third dilution treatment device 40 using the ejector 43, but this is not limited thereto. Instead of the ejector 43, the gas A may be introduced from the second dilution treatment device 30 to the third dilution treatment device 40 through a pipe connecting the second tank 31 and the third tank 41. Furthermore, instead of the ejector 43, a static mixer, a microreactor, or the like capable of mixing the gas A with the absorption liquid L may be used. Furthermore, in each of the above embodiments, the bubble generation unit 23 is provided so as to extend in the vertical direction, but this is not limited thereto. The bubble generation unit 23 may be provided so as to extend horizontally or obliquely. Furthermore, in each of the above embodiments, the bubble generation unit 23 is provided in the lower part of the first tank 21, but this is not limited thereto. The bubble generation unit 23 may be provided in a position other than the lower part of the first tank 21.

[0063] <Additional Notes> The ammonia abatement systems 100A to 100C described in the respective embodiments can be understood, for example, as follows.

[0064] (1) The ammonia detoxification systems 100A to 100C according to the first aspect each include a first dilution treatment device 20, 80 including a first tank 21, 81 storing an absorption liquid L capable of absorbing ammonia, a gas inlet line 22 for introducing a gas G to be ablated containing ammonia into the first tank 21, 81, a bubble generation unit 23 for generating bubbles B in the absorption liquid L by the gas G to be ablated introduced through the gas inlet line 22, and generating an ascending flow F in the absorption liquid L as the bubbles B rise, a bubble atomization unit 24 provided above the bubble generation unit 23 for atomizing the bubbles B, and a first gas delivery line 25, 85 for delivering a gas A from the gas phase in the first tank 21, 81 to the outside of the first tank 21, 81. The absorption liquid L may be fresh water or seawater.

[0065] In these ammonia abatement systems 100A to 100C, when the gas G to be abatement is introduced into the first tank 21, 81 via the gas inlet line 22, bubbles B are generated in the absorption liquid L in the bubble generation section 23. These bubbles B rise in the absorption liquid L, generating an ascending current F in the absorption liquid L. The bubbles B contained in the ascending current F are atomized by the bubble atomization section 24 provided above the bubble generation section 23. This makes it easier for the ammonia contained in the bubbles B to be absorbed into the absorption liquid L. Therefore, it is possible to efficiently absorb ammonia into the absorption liquid L while suppressing an increase in the amount of absorption liquid L and an increase in the size of the apparatus.

[0066] (2) The ammonia detoxification systems 100A to 100C according to the second aspect are the ammonia detoxification systems 100A to 100C of (1), and further include a second dilution treatment device 30 including: a second tank 31 in which an absorption liquid L capable of absorbing the ammonia is stored and which can temporarily store the gas A delivered from the first gas delivery line 25; an absorption promotion section 32 which promotes the absorption of ammonia by the absorption liquid L in the second tank 31; and a second gas delivery line 35 which delivers the gas A from an upper portion of the second tank 31 to the outside of the second tank 31.

[0067] As a result, the ammonia contained in the gas A delivered from the first gas delivery line 25 of the first dilution treatment device 20 can be absorbed by the absorption liquid L stored in the second tank 31 of the second dilution treatment device 30. The second dilution treatment device 30 is provided with an absorption promoter 32, so that the ammonia can be efficiently absorbed by the absorption liquid L in the second tank 31. In this way, by passing the gas G through the first dilution treatment device 20 and the second dilution treatment device 30 in sequence, the ammonia contained in the abatement target gas G can be more effectively absorbed.

[0068] (3) The ammonia detoxification systems 100A to 100C according to a third aspect are the ammonia detoxification systems 100A to 100C according to (2), wherein the absorption promoter 32 further includes a spray unit 34 capable of spraying the absorption liquid L supplied from outside the second tank 31 from an upper portion of the second tank 31, and a circulation line 33 that discharges the absorption liquid L from a lower portion of the second tank 31 and circulates the absorption liquid L to the spray unit 34.

[0069] As a result, the spray section 34 sprays the absorption liquid L, which is supplied from outside the second tank 31, from the upper part of the second tank 31. As a result, the absorption liquid L comes into contact with the gas A delivered from the first gas delivery line 25, and the ammonia contained in the gas A is absorbed by the absorption liquid L. The absorption liquid L that has absorbed the ammonia is circulated to the spray section 34 through the circulation line 33. As a result, the ammonia contained in the gas A can be sufficiently absorbed while circulating the absorption liquid L in the second tank 31. Therefore, there is no need to increase the amount of the absorption liquid L or the capacity of the second tank 31.

[0070] (4) The ammonia detoxification systems 100A to 100C according to the fourth aspect are the ammonia detoxification systems 100A to 100C according to (2) or (3), and further include a first valve 37 that opens and closes the flow path of the gas A from the first gas delivery line 25 to the second tank 31, and a second valve 38 that opens and closes the flow path of the gas A from the second tank 31 to the second gas delivery line 35.

[0071] As a result, by opening and closing the first valve 37, it is possible to continuously interrupt the inflow of gas A from the first gas delivery line 25 into the second tank 31. Furthermore, by opening and closing the second valve 38, it is possible to continuously interrupt the outflow of gas A from the second tank 31 to the second gas delivery line 35. With the first valve 37 and the second valve 38 closed, it is possible to continuously bring the ammonia-containing gas A into contact with the absorption liquid L circulating in the second tank 31. Therefore, it is possible to sufficiently remove ammonia from the ammonia-containing gas A.

[0072] (5) The ammonia detoxification systems 100A to 100C according to a fifth aspect are any one of the ammonia detoxification systems 100A to 100C according to (1) to (4), and further include a third dilution treatment device 40 including: a third tank 41 in which an absorption liquid L capable of absorbing the ammonia is stored; an introduction section 42 that introduces the gas A delivered from the first gas delivery line 25 or the second gas delivery line 35 into the absorption liquid L of the third tank 41; and a third gas delivery line 45 that delivers the gas A from an upper portion of the third tank 41 to the outside of the third tank 41.

[0073] This allows the absorption liquid L stored in the third tank 41 of the third dilution treatment device 40 to absorb ammonia contained in the gas A delivered from the first gas delivery line 25, 85 of the first dilution treatment device 20, 80 or the second gas delivery line 35 of the second tank 31. In this way, ammonia can be more effectively absorbed from the gas A that has passed through the first dilution treatment device 20, 80, or the first dilution treatment device 20, 80 and the second dilution treatment device 30.

[0074] (6) The sixth aspect of the ammonia detoxification system 100A to 100C is any one of the ammonia detoxification systems 100A to 100C of (1) to (5), in which the bubble atomization section 24 has a pipe body 24p through which the ascending flow F flows, and a blade section 24w fixed inside the pipe body 24p and turbulently stirring the ascending flow F.

[0075] As a result, the target gas G to be ablated flowing through the compressed gas flow path 24r of the pipe body 24p is turbulently agitated by the blades 24w. This allows the bubbles B generated in the absorption liquid L by the target gas G to be ablated to be refined. Moreover, because the blades 24w are fixed inside the pipe body 24p, loss of the target gas G to be ablated when it flows through the compressed gas flow path 24r is reduced compared to when a porous body for refinement of the bubbles B is provided inside the pipe body 24p. Furthermore, because the blades 24w are fixed, damage to the target gas G is also reduced.

[0076] (7) The ammonia detoxification system 100C according to the eighth aspect is any one of the ammonia detoxification systems 100C according to (1) to (6), and further includes a concentration meter 91 that detects the ammonia concentration in the gas phase in the first tank 21, and introduction lines 92, 93 that can introduce an inert gas or air into the absorption liquid L in the first tank 21, 81 based on the ammonia concentration detected by the concentration meter 91.

[0077] Thus, based on the ammonia concentration in the gas phase in the first tank 21 detected by the concentration meter 91, an inert gas or air is introduced into the absorption solution L in the first tank 21 from the introduction lines 92, 93, thereby making it possible to reduce the ammonia concentration in the absorption solution L in the first tank 21. This improves the ammonia absorption performance of the absorption solution L, and makes it possible to increase the ammonia absorption efficiency in the first dilution treatment devices 20, 80.

[0078] (8) The ammonia detoxification system 100C according to the eighth aspect is any one of the ammonia detoxification systems 100C according to (1) to (7), and further includes a concentration meter 91 that detects the ammonia concentration in the gas phase in the first tank 21, and a purge gas introduction line 11 that can introduce a purge gas containing an inert gas into the first tank 21, and the purge gas introduction line 11 can adjust the flow rate of the purge gas introduced into the first tank 21 based on the ammonia concentration detected by the concentration meter 91.

[0079] This allows the ammonia detoxification process to be carried out efficiently within an appropriate range by adjusting the flow rate of the purge gas introduced into the first tank 21 based on the ammonia concentration in the gas phase in the first tank 21 detected by the concentration meter 91.

[0080] According to the ammonia detoxification system of the present disclosure, it is possible to efficiently absorb ammonia into the absorbing solution while suppressing an increase in the amount of absorbing solution and an increase in the size of the device.

[0081] REFERENCE SIGNS LIST 10 Gas introduction section 11 Purge gas introduction line 11v On-off valve 20 First dilution treatment device 21, 81 First tank 22, 82 Gas introduction line 23 Bubble generation section 24 Bubble atomization section 24h Opening 24p Pipe body 24r Compressed gas flow path 24w Wing section 25 First gas delivery line 30 Second dilution treatment device 31 Second tank 32 Absorption promotion section 33 Circulation line 33h Heat exchanger 33p Circulation pump 34 Spray section 35 Second gas delivery line 37 First valve 38 Second valve 39 Pressure sensor 40 Third dilution treatment device 41 Third tank 42 Introduction section 43 Ejector 43p Suction pipe 44 Pump 45 Third gas delivery line 46 Introduction section 46v Switching valve 50 DESCRIPTION OF SYMBOLS Atmospheric release line 51 Dilution line 60 Drain line 61 First liquid discharge line 61v On-off valve 62 Second liquid discharge line 62v On-off valve 63 Third liquid discharge line 63v On-off valve 70 Absorbent reuse line 72 Branch lines 71, 73 On-off valve 80 Fourth dilution treatment device (first dilution treatment device) 82v Switching valve 85 First gas delivery line 91 Concentration meter 92, 93 Introduction lines 92v, 93v On-off valve 95 Flow rate adjustment section 98 Oil recovery section 100A to 100C Ammonia abatement system A Gas B Bubbles F Upward flow G Gas to be abatement L Absorbent

Claims

1. An ammonia detoxification system comprising a first dilution treatment device including: a first tank storing an absorption liquid capable of absorbing ammonia; a gas inlet section for introducing a gas to be detoxified containing ammonia into the first tank; a bubble generation section for generating bubbles inside the absorption liquid by the gas to be detoxified introduced by the gas inlet section, thereby generating an upward flow in the absorption liquid as the bubbles rise; a bubble atomization section provided above the bubble generation section for atomizing the bubbles; and a first gas delivery line for delivering gas from the gas phase inside the first tank to the outside of the first tank.

2. The ammonia detoxification system according to claim 1, further comprising a second dilution treatment device including: a second tank in which the absorbing liquid capable of absorbing the ammonia is stored and which is capable of temporarily storing the gas delivered from the first gas delivery line; an absorption promotion unit which promotes the absorption of ammonia by the absorbing liquid in the second tank; and a second gas delivery line which delivers the gas from an upper part of the second tank to the outside of the second tank.

3. The ammonia detoxification system according to claim 2, wherein the absorption promotion unit further comprises: a spray unit capable of spraying the absorption liquid supplied from outside the second tank from an upper portion of the second tank; and a circulation line that discharges the absorption liquid from a lower portion of the second tank and circulates the absorption liquid to the spray unit.

4. The ammonia abatement system according to claim 2 or 3, further comprising: a first valve that opens and closes the flow path of the gas from the first gas delivery line to the second tank; and a second valve that opens and closes the flow path of the gas from the second tank to the second gas delivery line.

5. The ammonia detoxification system according to claim 2, further comprising a third dilution treatment device including: a third tank in which the absorption liquid capable of absorbing the ammonia is stored; an introduction section that introduces the gas delivered from the first gas delivery line or the second gas delivery line into the absorption liquid in the third tank; and a third gas delivery line that delivers the gas from an upper portion of the third tank to the outside of the third tank.

6. An ammonia detoxification system as described in claim 1 or 2, wherein the bubble-micronizing section has a pipe body through which the upward flow flows, and a blade section fixed inside the pipe body to turbulently agitate the upward flow.

7. The ammonia detoxification system according to claim 1 or 2, further comprising: a concentration meter that detects the ammonia concentration in the gas phase in the first tank; and an introduction line that can introduce an inert gas or air into the absorption liquid in the first tank based on the ammonia concentration detected by the concentration meter.

8. An ammonia detoxification system as described in claim 1 or 2, further comprising: a concentration meter that detects the ammonia concentration in the gas phase within the first tank; and a purge gas introduction line that can introduce a purge gas containing an inert gas into the first tank, wherein the purge gas introduction line is capable of adjusting the flow rate of the purge gas introduced into the first tank based on the ammonia concentration detected by the concentration meter.

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