Gas detoxification device and gas detoxification method

Abstract

To provide a gas detoxification device and gas detoxification method that facilitate design according to the flow rate of a detoxification target gas and stabilize the processing capacity of the detoxification target gas.SOLUTION: A gas detoxification device 1 comprises: a storage tank 10 that stores an absorption liquid 20 for absorbing a detoxification target gas; and a blowout pipe 30 that supplies the detoxification target gas into the storage tank 10. The blowout pipe 30 has a downward portion 33 extending vertically downward, at least part or all of the downward portion 33 is formed of a porous member 31. The porous member 31 is immersed in the absorption liquid 20. The detoxification target gas flows vertically downward through the downward portion 33 of the blowout pipe 30 and is discharged into the absorption liquid 20 through pores 32 of the porous member 31.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a gas abatement device and a gas abatement method. [Background technology]

[0002] To prevent high concentrations of target gases, such as ammonia gas, from being released into the atmosphere, bubble column absorbers are commonly used for gases that can be absorbed into liquid. In such absorbers, a blow-off pipe is installed at the bottom of the liquid layer that stores the absorbing liquid that absorbs the gas, allowing the gas to be blown into the liquid layer. The blow-off pipe must have multiple nozzle holes, and a certain amount of pressure loss must be configured in the nozzle holes to ensure that the gas is blown out uniformly from the nozzle holes. Furthermore, to operate as a gas abatement system, it is necessary to quickly exhaust the gas, so it is desirable to minimize the pressure loss in the blow-off pipe and nozzle holes.

[0003] Patent Document 1 discloses a bubble column type ammonia gas abatement device in which nozzle holes are installed in an outlet pipe extending along the bottom surface of a liquid tank that stores an absorption liquid, and bubbles of a mixed gas containing ammonia gas are released from the nozzle holes into the absorption liquid. The nozzle holes are arranged horizontally to eliminate distribution of pressure loss associated with the head pressure of the nozzle holes and to enable ammonia gas to be blown out uniformly from all nozzle holes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-71026 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, when a large amount of ammonia gas needs to be treated, the location of the nozzle holes needs to be expanded horizontally, which increases the installation area of ​​the liquid tank. Also, when foreign matter such as rust enters from the upstream side of the ammonia gas supply, the foreign matter accumulates and causes blockages, which can reduce the ammonia gas treatment capacity or increase the pressure loss in the blow-out pipe and nozzle holes, which can cause blow-out from the blow-out pipe, which is a problem.

[0006] An object of the present disclosure is to provide a gas abatement device and a gas abatement method that facilitates design according to the flow rate of the gas to be abated and stabilizes the processing capacity of the gas to be abated. [Means for solving the problem]

[0007] The gas detoxification device according to the present disclosure comprises a storage tank for storing an absorption liquid that absorbs the gas to be detoxified, and an outlet pipe for supplying the gas to be detoxified into the storage tank, the outlet pipe having a downward section that extends vertically downward, with part or all of the downward section being made of a porous member, and the porous member being immersed in the absorption liquid, and the gas to be detoxified flows vertically downward through the downward section of the outlet pipe and is released into the absorption liquid through the holes in the porous member.

[0008] The porous member may be made of a metal member having a plurality of holes.

[0009] The gas to be ablated may contain ammonia gas.

[0010] The porous member may be made of a metal member having a plurality of holes.

[0011] An end plate portion that closes the tip of the downward portion of the blowoff pipe may be provided below the porous member of the blowoff pipe.

[0012] The tip of the blow-out pipe below the porous member may be open vertically downward.

[0013] The storage tank may be provided with an open flow path for releasing the target gas to be ablated from the storage tank.

[0014] The gas detoxification method disclosed herein is a gas detoxification method in which a gas to be detoxified is supplied into a storage tank through an outlet pipe and absorbed into an absorption liquid stored in the storage tank, wherein the outlet pipe has a downward portion extending vertically downward, and part or all of the downward portion is made of a porous material, and the porous material is immersed in the absorption liquid, and the gas to be detoxified flows vertically downward through the downward portion of the outlet pipe and is released into the absorption liquid through the holes in the porous material. [Effects of the Invention]

[0015] According to the present disclosure, it is possible to provide a gas abatement device and a gas abatement method that facilitates design according to the flow rate of the gas to be abatement and stabilizes the processing capacity of the gas to be abatement. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing a gas detoxification device according to one embodiment. [Figure 2] FIG. 2 is an enlarged schematic view of the porous member in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, several exemplary embodiments will be described with reference to the drawings. Note that the dimensional proportions of the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0018] The gas detoxification device 1 will be described with reference to Fig. 1. As shown in Fig. 1, the gas detoxification device 1 according to this embodiment includes a storage tank 10 that stores an absorption liquid 20 that absorbs the gas to be detoxified, and an outlet pipe 30 that supplies the gas to be detoxified into the storage tank 10.

[0019] The gas to be ablated is not particularly limited, and may include, for example, a basic gas or an acidic gas. The basic gas preferably includes ammonia gas. The acidic gas may include at least one gas selected from the group consisting of carbon dioxide, sulfur dioxide, nitrogen dioxide, hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide, and preferably includes carbon dioxide.

[0020] The blow-off pipe 30 supplies the target gas to be abated into the storage tank 10. Therefore, the target gas is supplied to the blow-off pipe 30. The target gas to be abated may be supplied to the blow-off pipe 30 via a target gas supply flow path 40, as shown in FIG. 1 . For example, the target gas to be abated emitted from a source of the target gas, such as a power plant or a factory, may be collected via the target gas supply flow path 40 and supplied to the blow-off pipe 30. This method can reduce the amount of target gas to be abated released into the atmosphere. When the target gas to be abated contains carbon dioxide, the amount of carbon dioxide released into the atmosphere can be reduced. Alternatively, the target gas to be abated may be supplied to the blow-off pipe 30 from a tank containing the target gas via the target gas supply flow path 40.

[0021] The blowout pipe 30 has a downward portion 33 extending vertically downward. As shown in Fig. 1, the blowout pipe 30 may have a horizontal portion 34 extending horizontally and the downward portion 33. Alternatively, the blowout pipe 30 may have a portion (not shown) extending in an oblique direction instead of the horizontal portion 34, and may have the obliquely extending portion and the downward portion 33. Furthermore, the blowout pipe 30 may have only the downward portion 33 without having either a horizontal portion or an obliquely extending portion.

[0022] A part or the whole of the downward portion 33 of the blow-out pipe 30 is made up of the porous member 31, and the porous member 31 is immersed in the absorbing liquid 20. As shown in Fig. 1, the porous member 31 may be attached to a part of the downward portion 33. Alternatively, the entire downward portion 33 may be made up of the porous member 31, and the porous member 31 may be attached directly to the horizontal portion 34, for example.

[0023] The gas to be abated flows vertically downward through the downward portion 33 of the blow-off pipe 30 and is released into the absorption liquid 20 through the holes 32 of the porous member 31. As shown by the arrows in Figure 1, the gas to be abated supplied via the gas to be abated supply flow path 40 may pass through the horizontal portion 34 of the blow-off pipe 30, flow vertically downward through the downward portion 33, and be released into the absorption liquid 20 through the holes 32 of the porous member 31.

[0024] The downward section 33 of the blow-off pipe 30 is partly or entirely made of the porous member 31, and the holes 32 of the porous member 31 are arranged vertically downward, thereby reducing pressure loss in the blow-off pipe 30. Furthermore, by using the porous member 31 with the holes 32 arranged vertically downward, the degree of freedom in the arrangement of the holes 32 is improved compared to when the blow-off pipe 30 is installed horizontally and the holes 32 are arranged horizontally, and clogging by foreign matter such as rust accompanying the gas to be abatement can be suppressed.

[0025] Furthermore, by constructing a part or the whole of the downward portion 33 of the blow-off pipe 30 from the porous member 31, a wider horizontal area of ​​the storage tank 10 can be used as the gas absorption area compared to when the blow-off pipe 30 is installed horizontally, thereby increasing the installation efficiency of the blow-off pipe 30. Furthermore, it becomes possible to blow out the target gas to be abated from the blow-off pipe 30 at a planned gas flow rate according to the liquid level of the absorption liquid 20 and the amount of target gas to be abated to be treated, thereby achieving uniform gas absorption.

[0026] Furthermore, by forming a part or the whole of the downward portion 33 of the blow-off pipe 30 from the porous member 31, it is possible to prevent the absorption liquid 20 from penetrating into the inside of the blow-off pipe 30. If the blow-off pipe 30 were installed extending horizontally, or if the blow-off pipe 30 were installed extending vertically upward, the absorption liquid 20 would penetrate into the inside of the blow-off pipe 30 through the holes 32 of the porous member 31, which could make it difficult for the target gas to be abatement to be released into the absorption liquid 20.

[0027] Normally, the air inside the blow-off pipe 30 is replaced with air or nitrogen, and the pressure of this replacement keeps the interior of the blow-off pipe 30 free from the absorption liquid 20. Even if the absorption liquid 20 penetrates into the interior of the blow-off pipe 30 through the holes 32 of the porous member 31, the absorption liquid 20 does not penetrate above the porous member 31 because part or all of the downward portion 33 of the blow-off pipe 30 is made up of the porous member 31. In other words, the absorption liquid 20 does not penetrate up to the horizontal portion 34 in FIG. 1 . In this way, the downward portion 33 of the blow-off pipe 30 can prevent the absorption liquid 20 from penetrating into the interior of the blow-off pipe 30. From the above, the gas detoxification apparatus 1 can be easily designed according to the flow rate of the gas to be abated, and can provide a gas detoxification apparatus that stabilizes the treatment capacity of the gas to be abated.

[0028] The downward portion 33 of the blow-out pipe 30 is partly or entirely made up of the porous member 31, but the method for attaching the porous member 31 to the blow-out pipe 30 is not particularly limited. That is, in Fig. 1, the method for attaching the porous member 31 to the downward portion 33 is not particularly limited. For example, the porous member 31 may be attached to the blow-out pipe 30 by welding, or the porous member 31 may be joined to the blow-out pipe 30 using a flange and a bolt.

[0029] The porous member 31 is a member having a plurality of holes 32 formed therethrough in the thickness direction. It is not particularly limited as long as it has holes 32 through which the target gas to be abatement can pass. Examples of the porous member 31 include metal or resin members having a plurality of holes 32 formed therein by processing methods such as woven mesh, expanding, or punching. The porous member 31 is preferably a metal member having a plurality of holes 32, and more preferably a metal substrate, such as a punched metal, in which a large number of holes 32 are formed in a regular pattern. A punched metal is a metal material obtained by punching a metal material, such as aluminum, iron, or stainless steel, using a mold. Specifically, a punched metal pipe, which is formed by processing a punched metal into a pipe shape, can be used as the porous member 31.

[0030] The thickness of the porous member 31 is not particularly limited, but it is preferable to use a thickness equal to or less than that of the blow-off pipe 30, as long as the predetermined structure can be maintained. In addition, the diameter of the porous member 31 is not particularly limited, but it is preferable to make it equal to the diameter of the blow-off pipe 30.

[0031] The shape of the holes 32 of the porous member 31 is not particularly limited as long as it allows the gas to be ablated to pass through, and examples include circular, approximately circular, elliptical, approximately elliptical, polygonal, or approximately polygonal.

[0032] The size of the holes 32 in the porous member 31 does not necessarily have to be the same. For example, taking into account the hydraulic head pressure, the size of the holes 32 in the porous member 31 may gradually increase in the vertically downward direction. On the other hand, from the standpoint of productivity and cost of the gas detoxification device, it is preferable that the holes 32 in the porous member 31 have the same area. By making the holes 32 in the porous member 31 have the same area, there is no distribution in the flow rate of the target gas to be detoxified released from each hole 32, which makes it easier to design the gas detoxification device and improves productivity. Also, from the standpoint of cost, it is preferable to use a porous member 31, particularly a punched metal, in which a large number of holes 32 are formed in a uniform pattern that conforms to product standards.

[0033] FIG. 2 is an enlarged view of the porous member 31 in FIG. 1 , showing an example of a punched metal. The arrangement of the holes 32 in the punched metal is not particularly limited and may be, for example, a 60° staggered arrangement, a 45° staggered arrangement, or a parallel arrangement. In FIG. 2 , the hole diameter D is the diameter of the hole 32, and the pitch P is the distance between the centers of adjacent holes 32. The hole diameter D of the hole 32 is a size that ensures a predetermined blow-out surface velocity of the gas to be abated in the range of 1 m / s to 100 m / s, and is preferably 1 mm to 50 mm, more preferably 1 mm to 30 mm, and particularly preferably 5 mm to 12.5 mm. On the other hand, the pitch P of the holes 32 is not particularly limited as long as the strength of the porous member 31 can be maintained.

[0034] The ratio of the area of ​​the holes 32 to the total area of ​​the punched metal is called the aperture ratio. The aperture ratio of the holes 32 of the punched metal is preferably 20% or more and 90% or less, and more preferably 23% or more and 64% or less. By setting the aperture ratio of the holes 32 to 20% or more, the blow-out surface velocity of the gas to be abatement can be stabilized. Furthermore, by setting the aperture ratio of the holes 32 to 90% or less, the strength of the porous member 31 can be maintained.

[0035] As an example of the porous member 31, a punched metal pipe was used, with holes 32 arranged in a 60° staggered pattern, a hole diameter D of 5 mm, a pitch P of 7 mm, and a hole porosity of 46.3%. When operated under conditions where the target gas for abatement could be blown out from 75 rows of holes 32 arranged in the vertical direction at a blowing surface velocity of 5.2 m / s, the target gas for abatement was blown out from 25 rows of holes 32 in a 100 mm high area, with a blowing surface velocity of approximately 21 m / s. It was also confirmed that the dry pressure loss and head pressure at each of the holes 32 were balanced. From the above, it was found that this punched metal pipe could treat up to three times the target gas for abatement.

[0036] In this way, the porous member 31 of the gas detoxification apparatus 1 can be designed based on a planned treatment volume of the gas to be detoxified. Therefore, the gas detoxification apparatus 1 can be easily designed according to the flow rate of the gas to be detoxified, and a gas detoxification apparatus can be provided that stabilizes the treatment capacity of the gas to be detoxified.

[0037] The absorbing liquid 20 that absorbs the gas to be ablated is stored in the storage tank 10. The absorbing liquid 20 is not particularly limited as long as it has the function of absorbing the gas to be ablated, and may be, for example, water, an acidic aqueous solution, or a basic aqueous solution. When the saturation solubility of the gas to be ablated in the absorbing liquid 20 is low, an acidic aqueous solution or a basic aqueous solution is preferable in order to treat the gas to be ablated while neutralizing it with the absorbing liquid 20. Specifically, when the gas to be ablated is a basic gas, the absorbing liquid 20 is preferably an acidic aqueous solution containing at least one of an aqueous sulfuric acid solution and an aqueous hydrochloric acid solution. Furthermore, when the gas to be ablated is an acidic gas, the absorbing liquid 20 is preferably a basic aqueous solution containing at least one selected from the group consisting of ammonia water, an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, and an aqueous amine solution. In particular, when the gas to be ablated is carbon dioxide, the absorbing liquid 20 is preferably an aqueous amine solution.

[0038] 1, an end plate 35 that closes the tip of the blow-off pipe 30 may be provided below the porous member 31 of the blow-off pipe 30. By providing the end plate 35, it becomes possible to increase the internal pressure of the blow-off pipe 30, and to make the flow rate of the target gas to be abatement released from the holes 32 of the porous member 31 uniform.

[0039] Furthermore, if necessary, the end plate 35 may be provided with a function that allows it to be opened vertically downward. The end plate 35 that allows it to be opened vertically downward may be a rupture disk that releases the target gas to the outside when the target gas flows through the outlet pipe 30 at a pressure equal to or greater than a set value, or may be a lid that can be opened and closed as needed. By opening the end plate 35 at the tip of the outlet pipe 30, foreign matter such as rust that accompanies the target gas flowing through the outlet pipe 30 does not accumulate and clog the hole 32, allowing the target gas to be released normally. Furthermore, if the blowing pressure of the target gas becomes higher than expected, the target gas can be exhausted from the end plate 35 to the absorbing liquid 20, preventing the blowing pipe 30 from being blown out by the target gas.

[0040] On the other hand, the tip of the blow-off pipe 30 below the porous member 31 may be open vertically downward without the end plate 35. By always leaving the tip of the blow-off pipe 30 open, foreign matter such as rust that accompanies the gas to be abatement flowing through the blow-off pipe 30 does not accumulate inside the blow-off pipe 30 or clog the holes 32 of the porous member 31, allowing the gas to be abatement to function normally. This is particularly effective when the gas to be abatement contains a large amount of foreign matter.

[0041] When the amount of gas to be abated is large, installing multiple porous members 31 can ensure stable blowout of the gas to be abated. For example, the porous members 31 can be installed horizontally in parallel. That is, the blowout pipe 30 may have multiple downward sections 33, each of which may have a porous member 31. When the blowout pipe 30 has a horizontal section 34 and a downward section 33, multiple downward sections 33 may be attached to multiple locations on the horizontal section 34, and each of the multiple downward sections 33 may have a porous member 31. Alternatively, multiple blowout pipes 30 may be installed horizontally in parallel, each of which may have a downward section 33 and a porous member 31. Furthermore, multiple blowout pipes 30 may be installed vertically in parallel, each of which may have a downward section 33 and a porous member 31.

[0042] As described above, the gas detoxification device 1 may include a target gas supply flow path 40 for supplying the target gas to the blow-off pipe 30. Furthermore, a gas supply flow path 45 may be connected to the target gas supply flow path 40, as shown in FIG. 1 . By providing the gas supply flow path 45, it becomes possible to replace the target gas by flowing a gas that matches the target gas when supplying the target gas to the blow-off pipe 30. If the target gas is a flammable gas such as ammonia gas, it is preferable to flow a gas that does not contain oxygen, such as nitrogen. On the other hand, if the target gas is a non-flammable gas such as carbon dioxide, it is preferable to flow nitrogen, air, or oxygen to prevent the target gas from affecting the human body.

[0043] The gas detoxification apparatus 1 may include an open flow path 50 as shown in FIG. 1. By including the open flow path 50, it becomes possible to release the gas in the storage tank 10 to the atmosphere after the gas to be detoxified has been absorbed by the absorbing liquid 20. The gas detoxification apparatus 1 may also be connected to another gas absorption mechanism (not shown) via the open flow path 50, or to a separately installed gas detoxification apparatus 1. In other words, a gas detoxification system can be constructed in which gas detoxification apparatuses 1 are arranged in multiple stages, with one gas detoxification apparatus 1 serving as a unit. In this way, by treating the gas to be detoxified by having the absorbing liquid absorb the gas in multiple stages, the detoxification effect of the gas to be detoxified can be further improved.

[0044] As described above, the gas detoxification apparatus 1 according to this embodiment includes a storage tank 10 that stores an absorption liquid that absorbs a gas to be abated, and an outlet pipe 30 that supplies the gas to be abated into the storage tank 10. The outlet pipe 30 has a downward section 33 that extends vertically downward, and a portion or the entirety of the downward section 33 is made of a porous member 31, which is immersed in the absorption liquid 20. The gas to be abated flows vertically downward through the downward section 33 of the outlet pipe 30 and is released into the absorption liquid 20 through the holes 32 of the porous member 31. Therefore, the gas detoxification apparatus 1 can be easily designed according to the flow rate of the gas to be abated, and a gas detoxification apparatus can be provided that stabilizes the treatment capacity of the gas to be abated.

[0045] Next, a gas detoxification method according to this embodiment will be described. The gas detoxification method is a gas detoxification method in which a gas to be detoxified is supplied into the storage tank 10 through a blow-out pipe 30 and absorbed in the absorption liquid 20 stored in the storage tank 10. The blow-out pipe 30 has a downward section 33 extending vertically downward, and part or all of the downward section 33 is made of a porous member 31, which is immersed in the absorption liquid 20. The gas to be detoxified flows vertically downward through the downward section 33 of the blow-out pipe 30 and is released into the absorption liquid 20 through holes 32 in the porous member 31.

[0046] As described above, the blow-off pipe 30 has a downward-facing portion 33 extending vertically downward. By partially or entirely comprising the porous member 31, the pressure loss of the blow-off pipe 30 can be reduced. By using the porous member 31 with holes 32 arranged vertically downward, the flexibility of the arrangement of the holes 32 is improved compared to when the blow-off pipe 30 is installed horizontally, and blockage by foreign matter such as rust accompanying the target gas can be suppressed. Furthermore, by partially or entirely comprising the porous member 31, a wide horizontal area of ​​the storage tank 10 can be utilized as a gas absorption area, improving the installation efficiency of the blow-off pipe 30 and preventing the absorption liquid 20 from penetrating into the blow-off pipe 30. Furthermore, the porous member 31 can be designed based on the planned treatment volume of the target gas. Therefore, the gas detoxification apparatus 1 can provide a gas detoxification method that facilitates design according to the flow rate of the target gas and stabilizes the treatment capacity of the target gas.

[0047] Although several embodiments have been described, the embodiments can be modified or varied based on the above disclosure. All components of the above embodiments and all features described in the claims may be individually extracted and combined, unless they contradict each other.

[0048] This disclosure can contribute, for example, to Goal 13 of the United Nations-led Sustainable Development Goals (SDGs), "Take urgent action to combat climate change and its impacts." [Explanation of symbols]

[0049] 1 Gas removal equipment 10 Reservoir 20 Absorbent 30 Blowout pipe 31 Porous member 32 holes 33 Downward section 35 End plate part 50 Open Channel

Claims

1. a storage tank for storing an absorption liquid that absorbs the target gas to be abatement; an outlet pipe for supplying the target gas to be abatement into the storage tank; Equipped with the blow-out pipe has a downward portion extending vertically downward, and a part or the entirety of the downward portion is made of a porous material; the porous member is immersed in the absorption liquid; A gas abatement device, wherein the target gas to be abatement flows vertically downward through the downward portion of the blow-out pipe and is released into the absorbing liquid through the holes of the porous member.

2. 2. The gas detoxification apparatus according to claim 1, wherein the porous member is made of a metal member having a plurality of holes.

3. 3. The gas abatement apparatus according to claim 1, wherein the gas to be abated includes ammonia gas.

4. 3. The gas detoxification apparatus according to claim 1, wherein an end plate portion for closing a tip of the downward portion of the blow-out pipe is provided below the porous member of the blow-out pipe.

5. 3. The gas detoxification apparatus according to claim 1, wherein a tip of said blow-off pipe below said porous member is open vertically downward.

6. 3. The gas abatement apparatus according to claim 1, further comprising an open flow path for releasing the target gas to be abated from within the storage tank.

7. A gas detoxification method in which a target gas to be detoxified is supplied into a storage tank through an outlet pipe and absorbed in an absorption liquid stored in the storage tank, the blow-out pipe has a downward portion extending vertically downward, and a part or the entirety of the downward portion is made of a porous material; the porous member is immersed in the absorption liquid; A gas abatement method, wherein the target gas to be abatement flows vertically downward through the downward portion of the blow-out pipe and is released into the absorption liquid through the holes of the porous member.

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