Ammonia removal equipment and scrubber used therein

Abstract

In a treatment device that introduces ammonia gas and absorbs it into water, the pressure loss is reduced to improve absorption capacity, enabling the recovery of large volumes of low-pressure ammonia gas. [Solution] In a scrubber 11 in which an absorption section 14 for absorbing ammonia gas into water is provided above a water storage section 12 for storing water, and ammonia gas is brought into contact with the water flowing down the absorption section 14, the absorption section 14 is composed of an arrangement of multiple baffles 31 that are not horizontal and are inclined vertically, forming a space 35 below. Multiple layers of baffles 31 and space 35 are formed in the vertical direction, and the baffles 31 are made of a porous plate material having through holes 33 on which a water film made of water flowing on the surface can be formed.

Description

Technical Field

[0001] This invention relates to a device for removing ammonia gas in a facility for storing and supplying ammonia used, for example, in power generation fuel, denitration, etc.

Background Art

[0002] Patent Document 1 below discloses an ammonia storage and supply base for supplying ammonia gas to a boiler in a thermal power plant. Ammonia that does not generate carbon dioxide during combustion is attracting attention as a fuel that plays an important role in decarbonization, and its use is expected to expand.

[0003] That ammonia is stored in a tank as liquid ammonia and used. The storage may be carried out under high pressure or under low temperature. When storing under high pressure, a tank having sufficient strength is required. However, it is difficult to make the tank for storing under high pressure have a large capacity for large-scale consumption. Therefore, a low-temperature storage tank is used for the tank of Patent Document 1.

[0004] In low-temperature storage, boil-off gas always generates from liquid ammonia. Therefore, a boil-off gas treatment facility is connected to the low-temperature storage tank of Patent Document 1 to reliquefy the boil-off gas and return it to the tank, and the pressure of the low-temperature storage tank is kept constant. The boil-off gas treatment facility is configured to boost the boil-off gas to a predetermined pressure with a compressor and liquefy it with cooling water in a condenser.

[0005] In addition to treating the boil-off gas in this way, a safety valve is provided in the tank to ensure safety when the internal pressure of the tank suddenly rises. The ammonia gas discharged through the safety valve is treated with a separate decontamination device.

[0006] Generally, ammonia gas is dissolved in water to detoxify it, and one method for doing so involves using a dilution tank. This is done by blowing ammonia gas into the bottom of a dilution tank containing water. However, if the released ammonia gas is not at high pressure, it is difficult to dissolve due to the hydrostatic pressure. In other words, the method using a dilution tank cannot be used when liquefied ammonia is not stored in a high-pressure tank but at low temperatures, because the released gas pressure will be low.

[0007] Another method involves using a packed tower. However, in this case, the pressure loss is large relative to the absorption capacity. For this reason, packed towers are also unsuitable for processing low-pressure gases. If a fan (exhaust fan) is installed in front of the packed tower to forcibly dissolve ammonia gas, there is the disadvantage that air will be mixed with the ammonia gas. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2023-105853 [Overview of the project] [Problems that the invention aims to solve]

[0009] The main objective of this invention is to reduce pressure loss and increase absorption capacity so that large volumes of low-pressure ammonia gas can be recovered. [Means for solving the problem]

[0010] This invention provides the following scrubber (exhaust gas treatment device).

[0011] In other words, a scrubber in which an absorption section for absorbing ammonia gas into water is provided above a water reservoir, and an exhaust gas introduction space for introducing ammonia gas is formed between the absorption section and the water reservoir, consists of an arrangement of multiple baffles in the absorption section that are not horizontal but inclined vertically and form a space below. Multiple layers of baffles and space are formed in the vertical direction, and the baffles are configured to be porous with through holes that form a water film made of water flowing on the surface.

[0012] Such a scrubber sends the emitted ammonia gas or ammonia water containing dissolved ammonia gas to a downstream stage, and separates the ammonia, for example, in a dissolved form.

[0013] Unlike the packing material in a packed column, the absorption section in the above configuration is composed of baffles arranged to form a space below, and since the baffles are porous, the pressure loss is smaller compared to that of packing material. Moreover, the water passing through the absorption section has a large contact area with ammonia gas because the porous baffles, including through holes, form a water film on their surface. Such contact occurs across multiple layers in the vertical direction. [Effects of the Invention]

[0014] According to this invention, the scrubber has a configuration that allows for low pressure loss and a large contact area with water, so it can adequately process both low-pressure and large-volume ammonia gas. Furthermore, the scrubber efficiently obtains either released ammonia gas or ammonia water in which ammonia gas has dissolved. [Brief explanation of the drawing]

[0015] [Figure 1] A structural diagram illustrating the overview of a scrubber. [Figure 2] Schematic diagram of an ammonia removal system. [Figure 3] Schematic diagram of an ammonia removal system. [Figure 4] Schematic diagram of an ammonia removal system. [Figure 5]Perspective view of the absorption part of the scrubber. [Figure 6] Cross-sectional view showing the structure of the main part of the scrubber. [Figure 7] Cross-sectional view showing the operating state. <0000OB>Cross-sectional view showing the structure of the absorption part according to another example. [Figure 9] Cross-sectional view showing the structure of the absorption part according to another example. [Figure 10] Front view and perspective view of the baffle constituting the absorption part of FIG. 9. [Figure 11] Cross-sectional view showing the structure of the absorption part according to another example. [Figure 12] Cross-sectional view showing the structure of the absorption part according to another example. [Figure 13] Perspective view of the baffle unit constituting the absorption part of FIG. 2 and plan view of the baffle.

Mode for Carrying Out the Invention

[0016] One embodiment for carrying out this invention will be described below with reference to the drawings.

[0017] The scrubber according to the invention is a water absorption type exhaust gas treatment device that absorbs and treats surplus gas in equipment handling ammonia such as thermal power generation and denitration with water, and is incorporated into an ammonia decontamination device according to the application and used. The surplus gas (exhaust gas) to be treated includes, for example, boil-off gas discharged through a safety valve to prevent the pressure rise of an ammonia tank, and ammonia gas released during blowdown during regular inspections and the like. The state is not limited to the case of only gas (gas), but also includes the case of a gas-liquid mixed state and the case of liquid.

[0018] <000O101>First, the scrubber 11 as an absorption tower will be described, and then the ammonia decontamination device 71 will be described.

[0019] The scrubber 11 has a structure that allows for effective dissolution of ammonia gas with low pressure loss even at extremely low pressures. Specifically, as shown in Figure 1, the scrubber 11 has, from bottom to top, a water reservoir 12, an exhaust gas introduction space 13, an absorption section 14, and an upper space 15. The water reservoir 12, located at the bottom, stores water. An inlet 16 for introducing ammonia gas (GNH3) as exhaust gas is formed on the side of the exhaust gas introduction space 13, which is above the water reservoir 12. An exhaust gas introduction passage 17 for introducing exhaust gas from ammonia handling equipment is connected to the inlet 16. The absorption section 14, above the exhaust gas introduction space 13, absorbs ammonia gas by bringing it into contact with water. The upper space 15, which is above the absorption section 14, contains rising ammonia gas. In the drawing, solid dashed arrows indicate exhaust gas, and thick arrows indicate water.

[0020] The water storage section 12 and the absorption section 14 are connected externally by a circulation path 18. Specifically, a circulation path 18 is provided to circulate the water from the water storage section 12 to the absorption section 14, and the circulation path 18 is equipped with a circulation pump 18a.

[0021] In addition to these, the scrubber 11 is equipped with a water supply channel 19 for supplying water to the water storage section 12 and a cooler 21 for increasing the solubility of ammonia gas (Figures 2 to 4). In the figures, 22 is a chiller that supplies refrigerant to the cooler 21. In addition to these, an ammonia gas outlet channel 25 (Figures 2 and 3) for releasing ammonia gas from the upper space 15 or an ammonia water outlet channel 26 (Figure 4) for releasing ammonia water from the water storage section 12 is connected.

[0022] As shown in Figure 5, the absorption section 14 is equipped with a plurality of baffles 31, and above the baffles 31, a sprinkler pipe 32 is provided to supply water from the circulation path 18 onto the baffles 31.

[0023] The baffle 31 is not horizontal and is inclined vertically, with space below it. In other words, the surface that acts as a baffle is not horizontal and is inclined vertically, and when installed, it forms a predetermined space below it.

[0024] Furthermore, the baffle 31 is porous, having through-holes 33 that form a water film consisting of water flowing over its surface. In other words, the baffle 31 has multiple through-holes 33 of a size that allows a water film to form on the inner surface of the holes due to water flowing down from above. The formation of a water film on the inner surface of the holes means that the holes are not blocked by water, but rather the openings of the through-holes 33 are maintained. The size of the through-holes 33 is related to the surface tension of water, and is determined by the shape of the through-holes 33, the inclination during installation, the temperature, etc. The size of the through-holes 33 should be as small as possible while still allowing a water film 37 to form on the inner surface of the hole. This is to maximize the area of ​​the water film 37. The baffle 31 can be constructed from perforated metal with circular holes as through-holes 33, as shown in the illustrated example, or it can be constructed from, for example, a metal mesh.

[0025] The baffle 31 illustrated in Figure 5 has an equilateral angle shape. That is, it is a shape in which two identical strip-shaped baffle carriers 31a are joined together at one of their long sides. When the corner 34 where the baffle carriers 31a are joined is fixed in a symmetrical position with the vertically upward direction, a triangular rod-shaped space 35 is formed below the long baffle 31.

[0026] Baffles 31 of this shape are aligned. That is, they are arranged in rows with a predetermined order so as to occupy a certain space. In the illustrated example, the baffles 31 are aligned horizontally and vertically in a rectangular parallelepiped space that is square in plan view. As a result, multiple layers of baffles 31 and space 35 are formed in the vertical direction. Since the baffles 31 and the space 35 below them are arranged regularly and occupy a certain space, the absorption section 14 has a structure that has a uniform predetermined space ratio throughout.

[0027] Figure 6 shows a cross-sectional view of the scrubber 11 as seen from the front. All baffles 31 face the same direction and in the same orientation, and are arranged parallel to each other at equal intervals. Specifically, the arrangement of the baffles 31 is as follows: One baffle support 31a of one baffle 31 is placed on or near the extension of the plate surface of one baffle support 31a of the same baffle 31. The other baffle support 31a of the other baffle 31 is placed on or near the extension of the plate surface of the other baffle support 31a of the same baffle 31. When aligned in this way, the multiple baffles 31 are arranged in a diagonal grid pattern in the vertical cross-section. The position of the corners 34 of the baffles 31 in the left-right direction is shifted by half a baffle 31 between adjacent baffles 31 in the vertical direction. As a result, there are areas where no baffle support 31a is present on the upper and lower edges of a given space where the baffles 31 are aligned.

[0028] Narrow gaps 36 are formed between the aligned baffles 31. The gaps 36 should be large enough to allow a water film to form on their surface, similar to the through-holes 33 mentioned above, that is, large enough to allow gas to pass through.

[0029] In the illustrated example, the plan view shape of the absorption section 14 is square and all baffles 31 are the same length. However, if the plan view shape of the absorption section 14 is circular, the lengths of the aligned baffles 31 will differ depending on the location where they are installed, corresponding to the circular shape. Even in this case, since the baffles 31 and the space 35 below them are regularly arranged and occupy a certain amount of space, the absorption section 14 has a configuration that has a uniform predetermined space ratio throughout.

[0030] The sprinkler pipe 32 has multiple nozzles 32a that spray water downwards, and multiple pipes are arranged in parallel to ensure even water spraying. The longitudinal direction of the sprinkler pipe 32 can be perpendicular to the longitudinal direction of the baffle 31 as shown in the illustrated example, or it can be aligned with the longitudinal direction of the baffle 31, or it can be angled to the longitudinal direction of the baffle 31.

[0031] As shown in Figure 6, the ammonia gas that enters the exhaust gas introduction space 13 from the inlet 16 rises and comes into contact with the water that is sprayed from the sprinkler pipe 32 and descends.

[0032] Specifically, as shown by dashed lines in Figure 7, a water film 37 is formed on the surface of the baffle 31. The water sprayed from the sprinkler pipe 32 flows down without interruption, forming a water film 37 on the upper and lower surfaces of the baffle 31, as well as on the inner surface of the through-holes 33 that connect them. Meanwhile, the ammonia gas rises against the movement of the water through the gaps 36 between the baffles 31, which are covered with the water film 37. The ammonia gas passes over the surface of the baffle 31, as well as through the through-holes 33 and the gaps 36, repeatedly passing through the baffle 31 and the space 35. In the process of rising, the ammonia gas comes into contact with water and is absorbed, and the water containing dissolved ammonia gas flows down and accumulates in the water reservoir 12.

[0033] Here, we will briefly describe some other examples of the specific configuration of the absorption section 14. In this description, parts that are common with the previously described configuration, such as the through-hole 33, will be denoted by the same reference numerals as before, and their detailed explanation will be omitted.

[0034] Figure 8 shows an example where the orientation of the baffles 31, which form the same equilateral angle shape as described above, is staggered among the baffles 31 arranged vertically. In other words, the orientation of multiple baffles 31 arranged at the same height is different from that of multiple baffles 31 arranged below or above them. The illustrated example shows an arrangement where the baffles are rotated by 90 degrees in a plan view, resembling a grid.

[0035] Figure 9 shows an example in which a baffle 31 with a vertical cross-section X-shaped is used instead of an equilateral angle baffle 31. As shown in Figure 9, the X-shaped baffles 31 are arranged so that the plate surfaces of the baffle carriers 31a are aligned in a straight line, either in contact with each other or with gaps between them (not shown), with the baffle carriers 31a in a uniform orientation in all directions around the central intersection.

[0036] The X-shaped baffle 31 can be composed of two baffle segments 31b as shown in Figure 10. That is, the baffle segments 31b are formed in the shape of a wide rectangular plate, as if two baffle carriers 31a were placed side by side, and two of these are assembled to form a pair of baffle segments 31b. At the midpoint in the width direction of the baffle segments 31b, a combination groove 38 is formed from one end in the longitudinal direction to the middle, and the two baffle segments 31b are fitted together and joined using the combination groove 38, as shown in the lower part of Figure 10. Near the midpoint in the width direction, a through groove 39 is formed that extends along the longitudinal direction and is partially parallel to the combination groove 38. The through groove 39, like the through hole 33 described above, is sized to allow a water film to form on its surface, that is, to allow gas to pass through.

[0037] Figure 11 shows an example in which a baffle 31 with a semicircular cross-sectional shape is used instead of an equilateral angle baffle 31. Because it is semicircular, the baffle 31 is not horizontal and is inclined vertically, forming a space 35 below. The arrangement shown is the same example as in Figure 6. In addition, they may be arranged with alternating orientations as shown in Figure 8.

[0038] Figure 12 shows a baffle 31 that is not the elongated shape described above, but rather a baffle 31 with a baseless hollow body in a conical shape, such as a pyramidal or conical shape, as a single unit (baffle unit 31c). In the illustrated example, the baffle unit 31c is a square pyramidal shape, and the space 35 below it is also square pyramidal. Here, a baffle 31 is formed when baffle units 31c are joined together horizontally. That is, baseless conical baffle units 31c, as shown in Figure 13(a), are joined together with their vertices pointing vertically upward and in an equal position in the left-right direction to form a single baffle 31 as shown in Figure 13(b). There may be gaps between the baffle units 31c. Multiple baffles 31 are arranged so that the lower ends of other baffles 31 are placed on top of the vertices of one baffle 31, and the baffles 31 and the space 35 below them are evenly aligned both horizontally and vertically. Note that in the illustration in Figure 13(b), the through hole 33 is omitted for convenience.

[0039] A scrubber 11 equipped with an absorption section 14 as described above constitutes an ammonia abatement device 71 as follows. The way in which the scrubber 11 is applied to the ammonia abatement device 71 can be broadly divided into two types depending on the treatment method. One is a batch type, and the other is a continuous type.

[0040] The batch type is an operating method in which ammonia gas absorption (dissolution) and release are performed in a single tower, and the treatment is performed each time exhaust gas is introduced. The exhaust gas includes boil-off gas and ammonia gas generated during blowdown. This device is suitable for use in facilities equipped with small or medium-sized ammonia tanks.

[0041] The batch-type ammonia abatement system 71, as shown in Figure 2, is equipped with a scrubber 11 with the aforementioned configuration at the uppermost position. As described above, the scrubber 11 has a water storage section 12, an exhaust gas introduction space 13, an absorption section 14, an upper space 15, an inlet 16, a circulation path 18, a circulation pump 18a, a water supply path 19, and a cooler 21. In particular, the batch type is equipped with a heater 72 in the circulation path 18. The heater 72 has the function of releasing ammonia gas from the ammonia water sent to the absorption section 14. The water after the ammonia gas has been released and separated flows down through the absorption section 14, while the released ammonia gas moves to the upper space 15.

[0042] The aforementioned ammonia gas outlet 25, which recovers the emitted ammonia gas, is connected to this upper space 15. Connected to the end of the ammonia gas outlet 25 are a compressor 73 and a liquefaction unit 74, which serve as a liquefaction device for liquefying the recovered ammonia gas, and a recovery tank 75 for recovering the liquefied ammonia liquefied by the liquefaction means. In the diagram, 76, which is the stage before the compressor 73, is a mist separator.

[0043] The ammonia removal device 71, consisting of these components, has a computer-controlled control unit (not shown), which performs the following operations.

[0044] If the ammonia gas being introduced is a boil-off gas, the ammonia handling facility should be equipped with a pre-release detection means to detect the stage immediately before the boil-off gas is released, on the ammonia tank side where the ammonia gas is stored. The pre-release detection means can consist of a pressure switch installed in the ammonia tank, which detects the set pressure of the safety valve (low-pressure safety valve) in the off-gas line that releases the boil-off gas. The off-gas line should also be equipped with a blow-off detection means to detect when the safety valve stops blowing or blows out. The blow-off detection means can consist of, for example, a flow meter installed downstream of the safety valve in the off-gas line.

[0045] The control unit starts the circulation pump 18a based on the detection signal from the pre-discharge detection means. The refrigerator 22 and liquefier 74 are kept in standby (operating) mode.

[0046] Subsequently, when the safety valve of the off-gas line opens, the exhaust gas (ammonia gas) introduced into the exhaust gas introduction space 13 comes into contact with the cooled water flowing from the water storage section 12 through the circulation path 18 to the absorption section 14. In the absorption section 14, the water forms a wide water film 37 on the surface of the baffle 31 which has through holes 33, and the ammonia gas comes into contact with this water film 37 and dissolves. As a result, the ammonia concentration in the water of the water storage section 12 increases.

[0047] After the safety valve has finished operating, that is, after it has stopped blowing and the system is completely safe, the heater 72, compressor 73, and liquefaction unit 74 are manually started to draw in the ammonia gas discharge passage 25 and liquefy it. The liquefied ammonia is then recovered in the recovery tank 75.

[0048] In this manner, the batch-type ammonia abatement device 71 efficiently adsorbs ammonia with low pressure loss by utilizing a large-area water film 37, even when the ammonia gas is released at low or extremely low pressure through a low-pressure safety valve.

[0049] Furthermore, since the adsorption and detachment of ammonia gas to obtain liquefied ammonia are performed in a single column, namely the scrubber 11, there is no need to have another column, such as a distillation column, resulting in a simple configuration, and the entire ammonia abatement device 71 can be made compact.

[0050] Furthermore, the water in the reservoir 12 is circulated, and the ammonia gas emitted from the scrubber 11 is discharged, so the water can be used for the next recovery treatment. In other words, it can be a closed system that basically does not require new water supply.

[0051] Similarly, if the ammonia gas being introduced is the same as that used for blowdown, the circulation pump 18a is operated in advance before introducing the ammonia gas, and other necessary equipment is put into standby (operational) mode. After the introduction is complete, the compressor 73 is started.

[0052] As mentioned above, the batch-type ammonia abatement device 71 has a simple configuration and can be miniaturized, so it can be made into a mobile ammonia abatement device 71 that does not have a recovery tank 75, as shown in Figure 3.

[0053] A mobile system is one in which the batch-type ammonia abatement device 71 can be treated as a single unit and is transportable by being mounted on a vehicle such as a truck.

[0054] In the mobile ammonia abatement device 71, a movable cylinder 76 is connected instead of a recovery tank 75 to recover liquefied ammonia.

[0055] The mobile ammonia abatement device 71 is particularly suitable for recovering ammonia gas during blowdown.

[0056] The continuous system is an operating method in which ammonia gas absorption (dissolution) and release are performed in separate towers, and the treatment is carried out continuously, including during the introduction of exhaust gas. This system is suitable for use in facilities equipped with large ammonia tanks.

[0057] As shown in Figure 4, the continuous ammonia abatement system 71 is equipped with a scrubber 11 with the above configuration at the uppermost part. The scrubber 11 has a water storage section 12, an exhaust gas introduction space 13, an absorption section 14, an upper space 15, an inlet 16, a circulation path 18, a circulation pump 18a, a water supply path 19, and a cooler 21, as described above.

[0058] The ammonia water outlet 26, which discharges ammonia water that has absorbed ammonia gas, is connected to the upper part of the water storage section 12, and a distillation column 77, which separates ammonia gas and water, is connected to the end of the ammonia water outlet 26. The water separated in the distillation column 77 is water that allows for the discharge of wastewater with a low ammonia concentration.

[0059] A condenser 79 is provided at the top of the distillation column 77 in the withdrawal passage 78 to liquefy the obtained ammonia gas, thereby obtaining liquid ammonia as distillate. The liquid ammonia can be returned to the ammonia tank. In Figure 4, 81 is a booster pump 81 for transferring the fluid to a position higher than itself.

[0060] A water extraction channel 82, which extracts water (dilute ammonia water that can be drained) from the bottom of the distillation column 77, is connected to a distillation return line 83 that returns the extracted water back to the distillation column 77. A reboiler 84 for heating and boiling the water is provided in the distillation return line 83.

[0061] The distillation return line 83 can also be connected to an absorption return line 85, which allows the separated water to be sent back to the scrubber 11. The absorption return line 85 may be equipped with a cooler 86 for cooling the water passing through it.

[0062] The ammonia removal device 71, consisting of these components, has a computer-controlled control unit (not shown), which performs the following operations.

[0063] In the case of a continuous ammonia abatement system 71, the circulation pump 18a, etc., is kept running at all times. As described above, the ammonia tank side of the ammonia handling equipment that stores ammonia gas may be equipped with the same pre-release detection means as described above to detect the stage before the release of boil-off gas, and may be activated based on the detection signal from the pre-release detection means. The off-gas line is also equipped with a blow detection means to detect when the safety valve stops blowing or blows out. The blow detection means can be configured, for example, as a flow meter installed downstream of the safety valve in the off-gas line.

[0064] When the safety valve on the off-gas line opens, the exhaust gas (ammonia gas) introduced into the exhaust gas introduction space 13 comes into contact with cooled water flowing from the water storage section 12 through the circulation path 18 to the absorption section 14. In the absorption section 14, the water forms a wide water film 37 on the surface of the baffle 31 which has through holes 33, and the ammonia gas comes into contact with this water film 37 and dissolves. As a result, the ammonia concentration in the water in the water storage section 12 increases.

[0065] After receiving the safety valve open signal, the control unit starts the booster pump 81 once the ammonia concentration in the water storage unit 12 has risen to a certain level. The booster pump 81 can be started based on the time elapsed since the detection of the rising ammonia concentration by a sensor or the blowout from the safety valve by a blowout detection means.

[0066] When the booster pump 81 is activated, it pressurizes the ammonia water and sends it to the distillation column 77. The ammonia gas distilled in the distillation column 77 and exiting through the extraction channel 78 is liquefied in the condenser 79 to become liquefied ammonia, which is then recovered. Meanwhile, the water extracted from the water extraction channel 82 is returned to the distillation column 77 through the reboiler 84, becoming water with a lower ammonia concentration, and can be discharged as wastewater. In parallel or selectively, the water extracted from the water extraction channel 82 is supplied to the scrubber 11 through the absorption return line 85 and used again to absorb ammonia gas. The control unit is configured to perform these flow path switching operations using PID control or the like based on the ammonia concentration in each section.

[0067] In the ammonia abatement device 71 equipped with the scrubber 11 configured as described above, the baffles 31 constituting the absorption section 14 of the scrubber 11 are formed in a porous manner and are regularly arranged to have a space 35 below them, resulting in low pressure loss. Therefore, even low-pressure boil-off gas can be absorbed by the water. Moreover, since a water film 37 is formed on the surface of the baffles 31, including the through holes 33, a large area of ​​the water film 37 can be obtained, allowing for efficient contact with the ammonia gas. Therefore, even large amounts of ammonia gas can be dissolved efficiently without leakage.

[0068] Furthermore, the ammonia abatement device 71 equipped with such a scrubber 11 is configured to operate the circulation pump 18a before the safety valve blows out when boil-off gas is introduced as exhaust gas, so that ammonia gas can be recovered and processed without leakage.

[0069] The batch-type ammonia abatement device 71, in particular, is configured to dissolve and remove ammonia in the scrubber 11, allowing for a compact and small-scale design that can be used for a variety of applications.

[0070] Furthermore, the continuous ammonia abatement system 71 is equipped with an absorption return line 85 that returns distilled and drainable water to the scrubber 11, thus enabling a closed system that eliminates or reduces the need for new water supply.

[0071] The above configuration is one embodiment for carrying out this invention, and this invention is not limited to the above configuration; other configurations can also be adopted.

[0072] For example, the through-hole 33 of the baffle 31 may not be circular; a hexagonal shape would allow for a larger surface area of ​​the water film 37. The baffle 31 may also be a flat plate.

[0073] The heater 72 in the circulation path 18 of the scrubber 11 of the batch-type ammonia abatement device 71 can also be provided in the water storage section 12. Furthermore, the arrangement of the heater 72 and the cooler 21 is not limited to that shown in the figure; for example, they can be reversed. Both the heater 72 and the cooler 21 can be appropriately configured with cooling water or steam, provided there is a sufficient heat source, so the installation location can be selected as appropriate.

[0074] Furthermore, in the batch-type ammonia abatement system 71, it is also possible to use the recovered ammonia in gaseous form without a liquefaction device.

[0075] In the batch-type ammonia abatement device 71, ammonia recovery may be performed automatically by a control unit rather than manually as described above. [Explanation of Symbols]

[0076] 11... Scrubber 12...Water storage section 14… Absorbent part 18...Circulation path 25…Ammonia gas outlet 26…Ammonia water outlet 31... Baffle 33…Through hole 34... Corner 35…Space 36... Gap 37…Water film 71... Ammonia removal equipment 72…Warmer 73... Compressor 74...Liquifier 77…Distillation column 85... Absorption return line

Claims

1. A scrubber in which an absorption section for absorbing ammonia gas into water is provided above a water storage section, and an exhaust gas introduction space for introducing ammonia gas is formed between the absorption section and the water storage section, The absorption section is composed of an arrangement of multiple baffles that are not horizontal and are inclined vertically, forming a space below. The baffle and the space are formed in multiple layers in the vertical direction, The baffle is porous, having through holes that form a water film consisting of water flowing on its surface. Scrubber.

2. The baffle has an equilateral angle shape, and the corners are positioned vertically upward and arranged in a symmetrical manner. The scrubber according to claim 1.

3. The baffles are arranged with gaps between them. The scrubber according to claim 1 or claim 2.

4. An ammonia abatement device equipped with a scrubber that absorbs ammonia gas into water, The scrubber comprises the scrubber described in claim 1 or claim 2, A circulation path is provided in the scrubber for circulating the water from the reservoir to the absorption section. An ammonia gas outlet is connected to the portion of the scrubber above the absorption section to recover the emitted ammonia gas. Ammonia removal device.

5. It is mobile. The ammonia removal apparatus according to claim 4.

6. An ammonia abatement device equipped with a scrubber that absorbs ammonia gas into water, The scrubber comprises the scrubber described in claim 1 or claim 2, A circulation path is provided in the scrubber for circulating the water from the reservoir to the absorption section. The water reservoir of the scrubber is connected to an ammonia water outlet passage for draining the ammonia water from the reservoir that has absorbed ammonia. A distillation column for separating ammonia water into liquefied ammonia and water is connected to the end of the aforementioned ammonia water outlet. Ammonia removal device.

7. An absorption return line is connected to the bottom of the distillation column to return the separated water to the circulation path. The ammonia removal apparatus according to claim 6.

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