JP2014042866A - Volatile organic compound removing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a volatile organic compound removing device capable of efficiently removing VOC.SOLUTION: The volatile organic compound removing device includes a nearly cylindrical removing column 1. In the cylindrical removing column 1, there are formed: a first filter 2 capable of holding a liquid right above the first filter 2; a first liquid layer 3 mainly made of water and disposed to contact with the first filter 2; a second liquid layer 4 mainly made of an organic solvent and disposed right above the first liquid layer 3; a second filter 5 arranged at a spacing from the second liquid layer 4 and capable of holding the liquid right above the second filter 5; and third liquid layers 6 and 7 disposed above the second filter and made of water.

Description

  The present invention relates to a volatile organic compound removing apparatus that removes a volatile organic compound.

  Volatile organic compounds (VOC) are toluene, isopropyl alcohol, xylene and acetic acid contained in paints, printing inks, adhesives, cleaning agents, gasoline, thinner and exhaust gas, etc. Substances such as ethyl are concerned about air pollution and adverse effects on the human body.

  Patent Document 1 discloses a water-soluble VOC gas processing apparatus that employs a gas-liquid contact structure. Patent Document 2 discloses a method for removing VOC contained in exhaust gas by dissolving or capturing a volatile organic compound contained in the exhaust gas in an emulsion of oil and water in an emulsion state. .

  As other methods, for example, those that decompose VOC using microorganisms, those that adsorb VOC with a filler such as activated carbon, and those that decompose VOC by combustion are known.

JP 2011-136281 A JP 2010-36136 A

  However, conventional volatile organic compound removal devices have poor VOC removal efficiency and a complicated structure. Therefore, in order to remove a sufficient amount of VOC, the size of the device must be increased, and a small and highly efficient VOC removal device that is simple in structure and easy to maintain while suppressing the introduction cost and operation cost is required. It was done.

  This invention is made | formed in view of the above, and makes it a main technical subject to provide the volatile organic compound removal apparatus which can fully remove VOC with a simple structure.

One aspect of the volatile organic compound removal apparatus according to the present invention includes a removal tower that configures a flow path for flowing a gas containing a volatile organic compound from below to above, a nozzle and a through hole provided in the flow path. A plate having, first to third liquid layers for adsorbing the gas, and an air layer,
The first and third liquid layers are both made of water or a water-soluble liquid, the second liquid layer is made of an organic solvent having a specific gravity smaller than that of the first liquid layer, and the first and second liquid layers are made of water. Are disposed at the bottom of the removal tower, the third liquid layer is disposed immediately above the plate having the through hole, the nozzle is provided in the first liquid layer, A plate having holes is provided above the second liquid layer via the air layer.
In the present specification, the phrase “nozzle” is “provided in the first liquid layer” is not limited to the case where the nozzle 2 is immersed in the liquid layer, and the nozzle 2 has a first nozzle outlet. It is understood to include the case where it is in liquid-tight contact with the liquid layer.

  One aspect of the method for removing a volatile organic compound according to the present invention is to volatilize the first and second liquid layers composed of water or a liquid composed of a water-soluble liquid and an organic solvent through a filter capable of holding the liquid directly above. And a third liquid layer mainly composed of water or an organic solvent through a filter disposed at a distance from the second liquid layer and capable of holding the liquid directly above. And passing the passed gas through.

  The volatile organic compound removing apparatus according to the present invention can efficiently remove VOC with a very simple structure.

Volatile organic compound removal apparatus according to the first embodiment Volatile organic compound removal apparatus of second embodiment Volatile organic compound removal apparatus of third embodiment Modified example of the volatile organic compound removing apparatus of the third embodiment Volatile organic compound removal apparatus of third embodiment Relationship between equipment operating days and toluene removal rate Sectional drawing which shows the volatile organic compound removal apparatus of 4th Embodiment. Diagram showing an example of a mesh plate Other configuration examples of nozzle 2

  Hereinafter, the present embodiment will be described in detail with reference to the drawings. The configurations with the same reference numerals in each figure indicate the same thing. The description of the present embodiment is interpreted for the purpose of understanding the technical idea of the present invention, and should not be construed as being limited to the description of the embodiment. Moreover, you may implement each embodiment combining each suitably.

(First embodiment)
FIG. 1 is a cross-sectional view showing a volatile organic compound removing apparatus according to the first embodiment. The arrows in the figure indicate the direction in which the gas G flows.

  The volatile organic compound removal apparatus 10 includes a substantially cylindrical removal tower 1 and a pump P for generating a gas flow inside the removal tower 1. The shape of the removal tower 1 may be any structure as long as it constitutes a flow path for circulating the gas G to be processed and a filter can be disposed in the flow path. The volatile organic compound removal apparatus 10 of the present embodiment is configured by only one removal tower (A).

  As shown in FIG. 1, a Buchner funnel type filter device 2 (nozzle) is provided at the lower portion of the removal tower 1 as an example. In this filter device 2, a filter plate 2a provided with a large number of pores is supported by a Buchner funnel type filter case 2b, and the other end communicates with a gas inlet 1a. In the present embodiment, the role of the “filter device 2” is not “Filtration” but a large number of bubbles. Therefore, the filter device in this specification is merely an example of a “nozzle”. In this sense, for example, a configuration in which thin tubes are bundled can be understood as being included in the “nozzle” of the present specification. That is, the complexity of the gas flow path does not matter.

  The filter plate 2a is, for example, a glass filter conforming to the ISO 4793 standard, and a pore size (pore size) of, for example, about 40 to 50 [μm] can be used, but is not limited thereto. Qualitatively, if the pores are too small, the flow rate of the gas G cannot be sufficiently secured, and the filter is likely to be clogged. On the other hand, if the pores are too large, the filter effect may be reduced. It can be said that there is. For this reason, it is necessary to set to an appropriate range as needed. Further, as will be described later, when the gas G passes through the filter plate 2a, it is necessary to generate a large number of bubbles. Therefore, the area of the filter plate 2a is preferably as large as the flow passage cross section of the removal tower 1.

  A first liquid layer 3 and a second liquid layer 4 are provided at the bottom of the removal tower 1. The liquid layer 3 is composed of water or a water-soluble liquid, and the liquid layer 4 is composed of an organic solvent or an oil-soluble liquid. For this reason, the liquid layer 3 becomes the lowermost layer and the liquid layer 4 appears in the upper layer in the state where the gas G is allowed to flow without flowing because of the specific gravity.

  The entire filter device 2 including the filter plate 2 a and the filter case 2 b is immersed in the liquid layer 3. That is, the amount of liquid is adjusted so that the boundary surface K between the liquid layer 3 and the liquid layer 4 is above the filter plate 2a. However, as will be described later with reference to FIG. 9, the entire filter device 2 is not necessarily immersed in the liquid layer 3, and the filter plate 2 a and the liquid layer 3 may be in contact with each other.

  Above the liquid surface H1 of the liquid layer 4 is an air layer S1, and a plate 5 having a through hole is provided above the air layer S1. The plate 5 having a through hole is liquid-tight but not air-tight, that is, a member that allows gas to pass but does not allow liquid to pass during gas flow. For example, a “mesh plate” in which a plurality of pores are provided in a plate made of metal or resin and processed into a mesh shape may be used. If the plate 5 having such a through hole is provided on the inner wall of the removal tower 1 without a gap, the liquid can be held immediately above by surface tension or the like despite the passage of gas. The aperture ratio of the pores to be provided in the plate 5 having the through holes is not particularly limited. However, if the pore diameter is too small, the flow rate of the gas G may decrease and the flow may stop. On the contrary, if the pore diameter is too large, the surface tension does not act sufficiently and the liquid layer is not liquid-tight and the liquid layer cannot be maintained. Therefore, it is necessary to select an optimal range appropriately in consideration of the processing target, target processing capability, the material and surface state of the mesh plate, thickness, shape, and the like. However, since the air layer S1 is pressurized from the atmospheric pressure during the circulation of the gas G, it is only necessary that the upper liquid layer 6 can be held during the circulation of the gas G. That is, as long as such a function is ensured, “plate” can be broadly understood, and includes, for example, “filter paper (filter paper)” that is not strictly plate-like.

  The liquid layer 6 is again sealed above the plate 5 having the through holes. Above the liquid surface H2 of the liquid layer 6 is an air layer S2. Although the liquid layer 6 shown in FIG. 1 shows the case where water or a water-soluble liquid is used, the liquid layer 6 may be an organic solvent or an oil-soluble liquid. In this case, the liquid may be composed of the same components as the liquid layer 3 or the liquid layer 4 or may be composed of different components. In order to increase the removal capability of oil-soluble VOC such as toluene, it is preferable to use an oil-soluble liquid, and in order to increase the removal capability of water-soluble VOC, it is preferable to use water or a water-soluble liquid. However, when operating in an environment where the liquid layer 6 has a low boiling point and easily volatilizes, it is necessary to pay attention to evaporation.

  Next, the operation of this apparatus will be described. When the gas G containing VOC is guided from the gas inlet 1a to the filter device 2 by operating the pump P, countless bubbles are generated when passing through a large number of pores of the filter plate 2a, and the liquid layer 3 and liquid The layer 4 is agitated to produce a mixed liquid layer mainly above the filter plate 2a. When the gas containing VOC passes through the mixed liquid layer, each of the water-soluble VOC and the oil-soluble VOC is removed.

  The gas G that has passed through this mixed liquid layer then passes through the air layer S1 above it to the plate 5 having a through hole, and reaches the liquid layer 6 held further upward. The water-soluble VOC remaining when passing through the liquid layer 6 is removed. Thereafter, the gas passes through the air layer S2 above the liquid layer 6 and is discharged from the gas discharge port 1c through the outlet portion 1b provided above.

  The pump P is for generating a gas flow. If the gas flow is obtained by other methods, the pump P is not necessary. Or unlike FIG. 1, the pump P may be provided in the gas inflow port 1a side. If the distance between the liquid layer 4 and the plate 5 having the through hole is secured to the extent that the mixed liquid of the liquid layers 3 and 4 formed when the gas G is passed does not contact the plate 5 having the through hole. Good.

  Since the specific gravity of the liquid layer 3 is larger than that of the liquid layer 4, the convection hardly occurs below the filter plate 2a, and does not contribute to the removal of the VOC gas. Therefore, for example, as shown in FIG. 9F, the filter device 2 may employ a configuration in which the end of the filter plate 2a is in contact with the inner wall of the removal tower without a gap. In this case, the filter plate 2a is liquid-tight when the gas G is circulated, but is not air-tight, that is, a member that allows gas to pass but does not allow liquid to pass. When such a configuration is employed, the amount of liquid used for forming the liquid layer 3 can be reduced.

  The pattern of the pores of the filter plate 2a may not be uniform. For example, the pore diameters may be different, and the number of pores may be different between the disk-shaped central portion and the peripheral portion. Alternatively, it may be eccentric instead of the concentric pattern. By adjusting these, foaming and jumping up into the air layer S1 can be suppressed.

As described above, the volatile organic compound removal apparatus 10 of the present embodiment has a very simple configuration in which a plurality of filters and a plurality of liquid layers are provided in the flow path of the removal tower that constitutes the flow path for circulating the gas G. Nevertheless, it is possible to construct a volatile organic compound removal device with extremely high removal efficiency, particularly in that both water-soluble volatile organic compounds and oil-soluble volatile organic compounds can be efficiently removed. it can.
A part of the first embodiment may be changed as follows. That is, when the gas to be removed is only water-soluble VOC, the liquid layer 4 may be omitted. The reason why the oil-soluble VOC may be deformed in this way is that the oil-soluble VOC is partially dissolved in “water or a water-soluble liquid” such as the liquid layer 3, but conversely, the water-soluble VOC is “organic” This is because it hardly dissolves in the “solvent or oil-soluble liquid”. In this case, the mixed liquid layer is not provided, but the apparatus configuration can be greatly simplified, and the operating cost can be greatly reduced.

(Second Embodiment)
FIG. 2 is a cross-sectional view showing the volatile organic compound removing apparatus 20 of the second embodiment. The difference from the volatile organic compound removing apparatus 10 of the first embodiment is that another plate 5 having a through hole is provided above the liquid layer 6 through the air layer (S2), and the upper layer thereof. 4 is further provided with a fourth liquid layer 7 composed of a water-soluble liquid, and is composed of only one removal tower (B) having a configuration different from that of the first embodiment. Above the liquid level H3 of the liquid layer 7 is an air layer S3, which is discharged from the gas discharge port 1c through an outlet portion 1b provided above the apparatus.

  Thus, in one removal tower, the VOC removal efficiency can be further enhanced by arranging three stages of liquid layers in series using two filter plates. If the plate 5 having more through holes is used to form a multistage liquid layer, the VOC removal efficiency can be further increased.

  When the liquid layers are configured in multiple stages as shown in the present embodiment, the liquid layer (the liquid layer 7 in the present embodiment) provided in the uppermost layer in order to suppress the evaporation of the organic solvent is a water-soluble liquid. It is preferable.

Example 1
First, the volatile organic compound removal apparatus 20 was created under the following conditions.

[Removal tower (B)]
Removal tower 1 ... Cylindrical polyvinyl chloride (PVC) pipe with a height of 1300 [mm], an inner diameter of 105 [mm], and an outer diameter of 115 [mm] Liquid layer 3 ... Water 1.5 [L] Liquid layer 4 in which aluminum sulfate 55 [g] is added to liquid hydrocarbon 4 ... hydrocarbon-based cleaning agent mainly composed of isoparaffin (Shellsol MC421 manufactured by Shell Chemicals Japan Co., Ltd.) 4.5 [L]
Liquid layer 6 and liquid layer 7... 1.0 [L] water filter device 2... Glass filter plate having a thickness of 6 [mm] and pore diameter of 40 to 50 [.mu.m] (compliant with ISO 4793 standard) )
Plate 5 having a through hole: a resin plate having an aperture ratio of 0.33% and a thickness of 3 [mm].

  Here, the mesh pattern is shown in FIG. In a circular shape having a diameter of 100 [mm] (region indicated by a broken line A1), 57 pores P having a diameter of 0.8 [mm] are provided approximately point-symmetrically from the axial center C of the removal tower 1.

  Under normal temperature and atmospheric pressure, the upper and lower ends of the removal tower 1 are closed, the inside is sealed, the pump P (discharge amount 6 [L / min]) is operated, and the gas G containing VOC flows into the apparatus from the gas inlet 1a. Then, the gas that passed through the inside of the apparatus was discharged from the gas discharge port 1c, and the gas discharged from the apparatus was collected with a detection tube and measured to examine the VOC removal rate.

  Toluene and isopropyl alcohol were used as VOCs. One hour and two hours after the apparatus 20 was operated, the VOC concentrations were measured near the gas inlet 1a and near the gas outlet 1c. The results are shown in Tables 1 and 2.

  From the results of Tables 1 and 2, it can be seen that when the volatile organic compound removing apparatus 20 is used, 91% or more of toluene and 98% or more of isopropyl alcohol can be removed 2 hours after the apparatus is operated. Thus, according to the structure of 2nd Embodiment, both the water-soluble volatile organic compound represented by isopropyl alcohol etc. and the oil-soluble volatile organic compound represented by toluene etc. can be removed very efficiently. It should be said that the fact that 91% of toluene, which is more difficult to remove compared with water solubility, can be removed and the effect can be maintained over 25 days is a remarkable effect that should be noted in comparison with the prior art.

(Third embodiment)
FIG. 3 is a cross-sectional view showing a volatile organic compound removing apparatus according to the third embodiment. As shown in this figure, the volatile organic compound removal apparatus 30 of this embodiment shows an embodiment in which two removal towers are connected in series. Note that each of the two removal towers (B, B) of the apparatus 30 shown in FIG. 3 has the same configuration as the removal tower of the volatile organic compound removal apparatus of the second embodiment.

-Modification-
Or when connecting two removal towers in series as shown in FIG. 4, you may vary the liquid layer structure of each removal tower. The removal tower in the figure is the same removal tower (B) as in the second embodiment. A Buchner funnel type filter device 2 is provided at the subsequent stage of the removal tower (B), and a removal tower (C) in which the entire filter device 2 is immersed in the fifth liquid layer 8 is connected. Above the liquid surface H4 of the liquid layer 8 is an air layer S4. The liquid layer 8 is preferably composed of water or a water-soluble liquid, but the component may be the same as or different from the liquid layer 6 or the liquid layer 7. The gas passes through the air layer S4 above the liquid layer 8 and is discharged from the gas outlet 1e through the outlet 1d at the end of the pipe provided above the inside of the removal tower.

  As understood from the above examples, VOC removal efficiency can be further enhanced by connecting a plurality of removal towers of the same kind or different kinds in series. In this case, the liquid layer disposed in the uppermost layer of each removal tower is preferably composed of water or a water-soluble liquid in order to suppress evaporation of the organic solvent.

-Example 2-
FIG. 5 shows a removal tower (B) similar to the removal tower 1 of the volatile organic compound removal apparatus 20 of the second embodiment, and a removal tower (A) of the volatile organic compound removal apparatus 10 of the first embodiment. A volatile organic compound removing device 50 is shown in which pipes are connected in series in this order by piping through a pump P. Using this apparatus 50, the relationship between the operating time of the apparatus and the removal rate of volatile organic compounds was examined.

[Removal tower (B)]
Removal tower 1... Cylindrical polyvinyl chloride (PVC) pipe having a height of 1300 [mm], an inner diameter of 105 [mm], and an outer diameter of 115 [mm]. Liquid layer 3... 2.0 [L] of water.
Liquid layer 4 ... hydrocarbon-based cleaning agent mainly composed of isoparaffin (Shellsol MC421 manufactured by Shell Chemicals Japan Co., Ltd.) 4.0 [L]
Liquid layer 6a ... hydrocarbon-based cleaning agent mainly composed of isoparaffin (Shellsol MC421 manufactured by Shell Chemicals Japan Co., Ltd.) 1.0 [L]
Liquid layer 7: Water 1.0 [L]
Filter device 2... Glass filter plate having a thickness of 6 [mm] and a pore diameter of 40 to 50 [[mu] m] (compliant with ISO 4793 standard)
Plate 5 having a through hole: a resin plate having an aperture ratio of 0.33% and a thickness of 3 [mm].
[Removal tower (A)]
Removal tower 1... Cylindrical polyvinyl chloride (PVC) pipe having a height of 1300 [mm], an inner diameter of 105 [mm], and an outer diameter of 115 [mm]. Liquid layer 3... 2.0 [L] of water.
Liquid layer 4 ... hydrocarbon-based cleaning agent mainly composed of isoparaffin (Shellsol MC421 manufactured by Shell Chemicals Japan Co., Ltd.) 3.0 [L]
Liquid layer 6b ... 1.0 [L] water filter device 2 ... thickness 6 [mm], pore diameter 40-50 [μm] glass filter plate (compliant with ISO 4793 standard)
Plate 5 having a through hole: a resin plate having an aperture ratio of 0.33% and a thickness of 3 [mm].

  Using the pump P, a gas containing toluene having a concentration of 400 μl / l (= ppm) was introduced into the apparatus from the gas inlet 1a, and the gas passed through the apparatus was discharged to the outside from the gas outlet 1c. Then, after flowing the gas into the apparatus and operating for 9 hours per day, the vicinity of the gas outlet 1c of the first removal tower (B), the vicinity of the gas outlet 1e of the second removal tower (A), The toluene concentration was measured respectively. The results are shown in Table 3.

  FIG. 6 is a diagram showing the relationship between the number of operating days of the apparatus 50 and the toluene removal rate. In FIG. 6, the concentration (μl / l) of toluene near the outlet 1b of the removal tower (B) in FIG. 5 is a rhombus (♦), and the concentration of toluene (μl / l) near the gas outlet 1e in FIG. Is represented by a square (■), and the toluene removal rate of the apparatus 50 of FIG. 5 is represented by a triangle (▲).

  As shown in FIG. 6, it can be seen that the apparatus 50 can remove 95% or more of toluene up to about 10 days (90 hours). And after about 10 days have passed since the operation of the device, the toluene removal rate decreased to 95% on the 18th (162 hours), and then maintained at 95% or more until 25 days (225 hours). I understand that.

  In addition, the concentration of toluene in the vicinity of the outlet 1b suddenly increased to 100 μl / l or more on the 11th day (93 hours) after operating the apparatus, and decreased to less than 75 μl / l on the 14th day (126 hours). ing. From this, it can be seen that in the removal tower (B) in the previous stage, the gas containing toluene was once retained inside by the liquid layer 7 of water. Similarly, the concentration of toluene in the vicinity of the gas discharge port 1e rises to 40 μl / l on the 11th day after operating the apparatus, and falls within 20 μl / l on the 18th day (162 hours). From this, it is considered that the removal tower (A) in the latter stage cannot immediately remove a large amount of toluene from the gas containing toluene, and it takes time to remove a large amount of toluene. Also, in the removal column (A) at the rear stage, it is considered that the gas containing toluene is once held inside by the liquid layer 26 of water as in the removal column (B) at the front stage.

  The reason why the removal rate once falls after 11th and recovers is unknown, and is considered to be a range of errors due to variations in measurement conditions. However, it can be seen that such a two-stage configuration can improve the VOC removal capability more reliably than the one-stage configuration.

(Fourth embodiment)
FIG. 7 is a cross-sectional view showing a volatile organic compound removing apparatus according to the fourth embodiment.

  The volatile organic compound removal apparatus 70 is further provided with a distillation apparatus 71 in the volatile organic compound removal apparatus 30 of the third embodiment. The distillation device 71 is connected to the upper side of the filter device 2 through a pipe 72, and the organic solvent is heated by a heating device (not shown) to separate and remove mainly VOC in the liquid layer 4 due to the difference in boiling point. can do.

  If comprised in this way, the removal capability of VOC can be recovered | restored by removing the VOC taken in into the liquid layer 4 with the distillation apparatus 71. FIG. The VOC removed by the distillation apparatus 71 may be concentrated and processed outside the apparatus. Further, the connection configuration of the distillation apparatus may be changed to separate and remove VOCs in other liquid layers.

DESCRIPTION OF SYMBOLS 1 Removal tower 1a Gas inlet 1b Outlet part 1c Gas outlet 2 Filter apparatus 2a Filter board 2b Filter case 3 Water or aqueous solution (1st liquid layer)
4 Organic solvent (second liquid layer)
5 Filter plate 6 Water or aqueous solution (third liquid layer)
7 Water or aqueous solution (fourth liquid layer)
8 Water or aqueous solution (5th liquid layer)
P Pump G Gas S1, S2, S3, S4 containing volatile organic compound (VOC) Air layer

Claims (12)

A removal tower constituting a flow path for flowing a gas containing a volatile organic compound from below to above;
A plate having a nozzle and a through-hole provided in the flow path, first to third liquid layers for adsorbing the gas, and an air layer;
Each of the first and third liquid layers is made of water or a water-soluble liquid,
The second liquid layer is made of an organic solvent having a specific gravity smaller than that of the first liquid layer,
The first and second liquid layers are both disposed at the bottom of the removal tower,
The third liquid layer is disposed immediately above the plate having the through hole,
The nozzle is provided in the first liquid layer;
The plate having the through hole is a volatile organic compound removing device provided above the second liquid layer via the air layer. A third filter is further provided above the third liquid layer via a second air layer,
The volatile organic compound removing apparatus according to claim 1, wherein a fourth liquid layer is provided as an upper layer.   The volatile organic compound removing apparatus according to claim 2, wherein the fourth liquid layer is composed of a water-soluble liquid.   An organic compound removal apparatus comprising a plurality of removal towers constituting the organic compound removal apparatus according to any one of claims 1 to 4, wherein the removal towers are connected in series. The volatile organic compound removal apparatus according to any one of claims 1 to 4, wherein the first filter is in contact with an inner wall of the removal tower without a gap. The volatile organic compound removing apparatus according to any one of claims 1 to 5, wherein a distillation apparatus is connected to the second liquid layer. A removal tower constituting a flow path for flowing a gas containing a volatile organic compound from below to above;
A nozzle provided in the flow path, and first and second liquid layers for adsorbing the gas,
The first liquid layer is made of water or a water-soluble liquid,
The second liquid layer is made of an organic solvent having a specific gravity smaller than that of the first liquid layer,
The first and second liquid layers are both disposed at the bottom of the removal tower,
The nozzle is provided in the first liquid layer;
The nozzle includes a filter plate having a large number of pores.   The volatile organic compound removing device according to claim 7, wherein the nozzle is a Buchner funnel type filter device.   The volatile organic compound removing apparatus according to claim 7 or 8, wherein the filter plate is a glass filter conforming to ISO 4793 standard.   The volatile organic compound removing apparatus according to claim 9, wherein the filter plate has a pore diameter of 40 to 50 μm. A removal tower constituting a flow path for flowing a gas containing a volatile organic compound from below to above;
A plate having a nozzle and a through-hole provided in the flow path, first and third liquid layers for adsorbing the gas, and an air layer;
Each of the first and third liquid layers is made of water or a water-soluble liquid,
The first is located at the bottom of the removal tower;
The third liquid layer is disposed immediately above the plate having the through hole,
The nozzle is provided in the first liquid layer;
The plate having the through hole is a volatile organic compound removing device provided above the second liquid layer via the air layer. Passing a gas containing a volatile organic compound through first and second liquid layers made of water or a liquid composed of a water-soluble liquid and an organic solvent through a filter capable of holding the liquid directly above;
Passing the passed gas through a third liquid layer mainly composed of water or an organic solvent through a filter disposed at a distance from the second liquid layer and capable of holding the liquid directly above. A method for removing volatile organic compounds, comprising:

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