VOC removal device

Abstract

This invention provides a VOC removal device that improves the removal performance of volatile organic compounds (VOCs) contained in a gas to be treated and decomposed by plasma. [Solution] The VOC removal device 1 includes a plasma processing channel 10 that generates plasma in the gas to be treated flowing through the channel 14, and an adsorption processing channel 20 that introduces the gas to be treated, from which volatile organic compounds have been decomposed in the plasma processing channel 10, and passes it through the adsorption layer 24. Because plasma is generated throughout the entire channel 14 by the discharge between the cylindrical surfaces of the cylindrical electrode 11 and the axial electrode 12, it is possible to continuously process the gas to be treated by sending it into the channel 14, plasmaizing it up to the downstream end of the channel 14, and then quickly sending it from the channel 14 to the adsorption processing channel 20.

Description

Technical Field

[0001] This invention relates to a VOC removal device for removing volatile organic compounds (VOCs: Volatile Organic Compounds) contained in a gas to be treated.

Background Art

[0002] In order to reduce environmental emissions into the atmosphere from factories and the like of volatile organic compounds such as toluene, benzene, xylene, ethyl acetate, dichloromethane, etc. that volatilize into the atmosphere at normal temperature and pressure, devices for removing volatile organic compounds are used.

[0003] As a device for removing volatile organic compounds contained in a gas to be treated, there is a plasma type that generates plasma in a high energy state by discharge in a plasma treatment path through which the gas to be treated flows, and decomposes the volatile organic compounds by the plasma (Patent Document 1). The plasma type VOC removal device disclosed in Patent Document 1 has the advantages that it can decompose and remove volatile organic compounds in the gas to be treated under normal temperature and atmospheric pressure, and can easily switch between operation and stop.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the VOC removal device of Patent Document 1 has room for improvement in that even if volatile organic compounds are decomposed into ions and molecules by plasma, the ions and the like recombine during the period from when the gas to be treated flows out of the plasma treatment path until it reaches the exhaust port, and volatile organic compounds are generated again.

[0006] In light of the above background, the problem that this invention aims to solve is to improve the removal performance of a VOC removal device that decomposes volatile organic compounds using plasma. [Means for solving the problem]

[0007] To achieve the above objectives, this invention provides a VOC removal device comprising a plasma treatment path that generates plasma in the gas to be treated flowing through a channel, and an adsorption treatment path that introduces the gas to be treated, from which volatile organic compounds have been decomposed in the plasma treatment path, and passes it through an adsorbent layer (hereinafter referred to as "Configuration 1").

[0008] According to the above configuration 1, volatile organic compounds contained in the gas to be treated are decomposed in the plasma treatment path, and the gas to be treated, containing the ions and molecules generated by the decomposition, is passed through the adsorbent layer of the adsorption treatment path and adheres to the adsorbent, thereby suppressing recombination with volatile organic compounds and improving the removal performance of volatile organic compounds.

[0009] In the above configuration 1, a configuration in which the adsorbent layer is a perlite layer (hereinafter referred to as "configuration 2") can be adopted.

[0010] According to the above configuration 2, the adsorbent layer is not flammable even when heated by the gas being treated, so it can be applied to gases being treated at higher temperatures compared to cases where flammable adsorbents such as activated carbon are used.

[0011] In the above configuration 1 or 2, a configuration can be adopted in which a plurality of the plasma processing paths and the adsorption processing paths are provided, and these plasma processing paths and adsorption processing paths are arranged alternately from the upstream side to the downstream side (hereinafter referred to as "configuration 3").

[0012] According to the above configuration 3, the volatile organic compounds can be removed multiple times between the time the gas to be treated is sent to the upstream plasma treatment path and discharged from the downstream adsorption treatment path. Therefore, the removal of volatile organic compounds from the gas to be treated is gradually advanced, and the final removal rate of volatile organic compounds can be increased.

[0013] In any one of the above configurations 1 to 3, a configuration (hereinafter referred to as "configuration 4") can be adopted in which the flow path of the plasma processing path is formed between a cylindrical electrode and an axial electrode coaxially arranged inside the cylindrical electrode, and plasma is generated in the gas to be processed by applying a voltage between the cylindrical electrode and the axial electrode, and the adsorption processing path is connected to the downstream side of the flow path of the plasma processing path.

[0014] According to the above configuration 4, the gas to be processed can be plasma-generated by applying voltage throughout the entire flow path between the cylindrical electrode and the axial electrode, and immediately sent to the adsorption processing path. This makes it easy to capture ions and other particles generated by the decomposition of volatile organic compounds in the adsorbent layer before they can recombine with the volatile organic compounds. [Effects of the Invention]

[0015] Thus, by adopting the above configuration 1, this invention can improve the removal performance of a VOC removal device that decomposes volatile organic compounds with plasma. [Brief explanation of the drawing]

[0016] [Figure 1] A longitudinal cross-sectional front view showing a VOC removal device according to the first embodiment of this invention. [Figure 2] Front view showing a VOC removal device according to a second embodiment of this invention. [Modes for carrying out the invention]

[0017] Hereinafter, a VOC removal device according to the first embodiment of this invention will be described based on Figure 1 of the attached drawings.

[0018] The VOC removal device 1 shown in FIG. 1 is composed of a single plasma treatment path 10 and a single adsorption treatment path 20 that is continuous downstream of the plasma treatment path 10.

[0019] The plasma treatment path 10 includes a cylindrical electrode 11, an axial electrode 12 arranged coaxially with the cylindrical electrode 11 inside the cylindrical electrode 11, a plurality of insulating spacers 13 for holding the axial electrode 12 coaxially with the cylindrical electrode 11, and an introduction path 15 for introducing the gas to be treated into the flow path 14 formed by the cylindrical electrode 11 and the axial electrode 12.

[0020] The plasma treatment path 10 allows the gas to be treated to flow from the introduction path 15 into the flow path 14, and gives electrical energy to the gas to be treated flowing through the flow path 14 by means of an electric field generated between the cylindrical electrode 11 and the axial electrode 12, thereby stably generating plasma in the gas to be treated under atmospheric pressure, and it is an atmospheric pressure plasma generator that allows the gas to be treated in which plasma has been generated to flow out from the flow path 14.

[0021] The cylindrical electrode 11 of the plasma treatment path 10 serves as a cathode provided in a cylindrical surface shape on the inner circumference of a straight pipe body. Hereinafter, the direction along the tube axis of the cylindrical electrode 11 is referred to as the axial direction, the direction perpendicular to the tube axis is referred to as the radial direction, and the circumferential direction around the tube axis is referred to as the circumferential direction.

[0022] The axial electrode 12 of the plasma treatment path 10 serves as an anode provided in a cylindrical surface shape on the outer circumference of a straight shaft body extending in the axial direction. The axial electrode 12 faces the cylindrical electrode 11 in the radial direction.

[0023] As the cylindrical electrode 11 and the axial electrode 12, it is preferable to use a seamless pipe without joints, and the material thereof is not particularly limited. For example, it may be a stainless steel pipe, or it may be a conductive resin (CFRP: Carbon Fiber Reinforced Plastics) pipe reinforced with carbon such as graphite or carbon nanotubes. Alternatively, it may be a pipe obtained by coating the inner peripheral surface or the outer peripheral surface of a stainless steel pipe with a resin layer containing carbon such as graphite or carbon nanotubes. Note that since seamless stainless steel pipes are expensive, heavy, difficult to withstand high temperatures of 400 °C or higher, and may be corroded by strong acids and strong alkalis, conductive resin pipes are more preferable.

[0024] The insulating spacer 13 is formed of, for example, a fluororesin or the like, which is excellent in chemical resistance and heat resistance. The insulating spacer 13 is preferably, for example, substantially X-shaped or substantially Y-shaped when viewed from the axial direction in order to make the core coaxially, and is preferably composed of a frame as thin as possible in order not to obstruct the flow of the processed gas.

[0025] The flow path 14 of the plasma processing path 10 is formed between the inner circumference of the cylindrical electrode 11 and the outer circumference of the axial electrode 12, and extends in the axial direction with an annular flow path cross section.

[0026] When a voltage of 13000 to 25000 V is applied between the cylindrical electrode 11 and the axial electrode 12 by an electric circuit connected to the cylindrical electrode 11 and the axial electrode 12, discharge is generated between the cylindrical electrode 11 and the axial electrode 12. Since electrical energy is given to the processed gas flowing in the electric field of this discharge, plasma is generated in the processed gas, the chemical bonds of the volatile organic compound in contact with the plasma are broken, and the volatile organic compound is decomposed. It is not necessary to add a gas for facilitating the generation of plasma to the processed gas, and it is better not to do so in consideration of the operation cost. For example, if a noble gas such as argon (Ar) gas or helium (He) gas is added to the processed gas and fed into the flow path 14, plasma is likely to be generated, but an expensive gas is used, which is not preferable.

[0027] Because plasma is generated throughout the entire flow channel 14 by the discharge between the cylindrical surfaces of the cylindrical electrode 11 and the axial electrode 12, it is possible to continuously process the gas to be processed by supplying it to the flow channel 14, converting it into plasma up to the downstream end of the flow channel 14, and then quickly sending it from the flow channel 14 to the adsorption processing channel 20.

[0028] Here, if there are irregularities on the cylindrical electrode 11 and the axial electrode 12, spark discharge will occur at those locations. When spark discharge such as corona discharge or glow discharge occurs, plasma is generated only in the vicinity of the spark discharge, making it difficult to achieve the effects of plasma treatment. Also, if the voltage applied between the cylindrical electrode 11 and the axial electrode 12 is too high, or if the distance between the cylindrical electrode 11 and the axial electrode 12 is too short, spark discharge may occur. The voltage of 23000V is the upper limit to prevent spark discharge when the distance between the cylindrical electrode 11 and the axial electrode 12 is 40mm. The voltage applied between the cylindrical electrode 11 and the axial electrode 12 should be adjusted appropriately according to the dimensions of the cylindrical electrode 11 and the axial electrode 12 so that spark discharge does not occur. Furthermore, the applied voltage should be such that the amount of nitrogen oxide (NOx) generated can be ignored. The position of the connection point between the cylindrical electrode 11 and the axial electrode 12 and the electrical circuit is not particularly limited, but in the illustrated example, it is located near the axial center of the cylindrical electrode 11 and the axial electrode 12.

[0029] To process a large amount of gas in the plasma processing path 10, for example, the inner diameter of the cylindrical electrode 11 is set to 100 mm, the outer diameter of the axial electrode 12 is set to 20 mm, and the axial length of the region where the cylindrical electrode 11 and the axial electrode 12 face each other radially is set to 1600 mm. These dimensions are just an example and are not limited to them. The outer diameter of the axial electrode 12 should be 10 mm or more. On the other hand, if the inner diameter of the cylindrical electrode 11 is made too large, the distance between the cylindrical electrode 11 and the axial electrode 12 becomes long, making it difficult for discharge to occur. For this reason, it is preferable to satisfy 3 ≤ (inner diameter of cylindrical electrode 11 / outer diameter of axial electrode 12) ≤ 6, (inner diameter of cylindrical electrode 11 - outer diameter of axial electrode 12) ≥ 20 mm, and the outer diameter of the axial electrode 12 ≥ 10 mm.

[0030] Furthermore, if the cylindrical electrode 11 and the axial electrode 12 are made too long in the axial direction, it becomes difficult to hold the cylindrical electrode 11 and the axial electrode 12 concentrically in the flow path 14 with the insulating spacer 13. To avoid this, it is preferable that the axial length of the flow path 14 be between 500 mm and 2000 mm.

[0031] The introduction passage 15 of the plasma processing passage 10 has a guide vane section that changes the flow of the gas to be processed toward the flow path 14 into a helical flow, and two or more obstruction sections that generate wake vortices in the aforementioned helical flow in the intermediate flow path between the guide vane section and the flow path 14. A plasma processing passage having such an introduction passage is disclosed in detail in Japanese Patent Application Publication No. 2021-126633.

[0032] The gas to be treated, introduced into the introduction channel 15, changes into a spiral flow (helical flow) that swirls in one direction downstream in the axial direction as it passes through the guide vane section. Further, upon hitting an obstacle, it changes into a spiral flow including a wake vortex, before flowing into the upstream inlet of the channel 14 and passing through the channel 14 as a spiral flow that swirls in one direction downstream in the axial direction. Due to this spiral flow and the generation of wake vortices, the gas to be treated flows along a longer path in the channel 14, increasing the probability that the molecules of the gas to be treated are affected by the plasma compared to when it flows straight in the axial direction.

[0033] While it is not essential to employ helical flow or wake vortex formation for the gas being treated, it is preferable to do so in order to increase the probability of decomposition of volatile organic compounds contained in the gas being treated. The axial length of the flow path 14 is preferably 1000 mm or more in order to increase the travel distance of the helical flow of the gas being treated.

[0034] The adsorption processing path 20 is a pipeline formed by a connecting path 21 connected to the downstream side of the flow path 14 of the plasma processing path 10, an adsorption pipeline 22 connected to the downstream side of the connecting path 21, and an exhaust path 23 connected to the downstream side of the adsorption pipeline 22.

[0035] The connecting passage 21 introduces the gas to be treated, which has flowed out from the downstream side of the flow path 14 of the plasma processing passage 10, to the upstream side of the adsorption pipeline 22. The adsorption pipeline 22 has an adsorbent layer 24 arranged inside a straight tube and permeable barriers 22a arranged on the upstream and downstream sides of the adsorbent layer 24, respectively. The exhaust passage 23 causes the gas to be treated, which has flowed out from the downstream side of the adsorption pipeline 22, to flow out of the adsorption processing passage 20.

[0036] The adsorbent layer 24 is formed by randomly packing numerous adsorbents 24a inside the adsorption conduit 22, and randomly creating gaps 24b between the layered adsorbents 24a to allow the gas to be treated to pass through. The adsorbent layer 24 is held in place by the upstream permeable barrier 22a and the downstream permeable barrier 22a. The permeable barrier 22a is a member that restricts the movement of the adsorbents 24a while allowing the gas to be treated to pass through, and is, for example, a mesh member that does not allow the adsorbents 24a to pass through.

[0037] Adsorbent material 24a is intended to capture ions and other substances generated by the decomposition of volatile organic compounds by adhering them to its surface. Examples of adsorbent material 24a include perlite and activated carbon. Perlite is a white, very light artificial sand (pumice) made by heating and foaming glassy volcanic rocks such as perlite and obsidian at high temperatures. Activated carbon and perlite have porous or foamed surfaces and are rich in surface irregularities, making it easy to physically or chemically adsorb ions and other substances generated by the decomposition of volatile organic compounds.

[0038] If the adsorbent layer 24 is made of a flammable adsorbent such as activated carbon, when the gas to be treated, such as exhaust smoke, which is at a temperature higher than room temperature, is passed through the plasma treatment path 10 and introduced into the adsorption treatment path 20, there is a risk that the adsorbent 24a will be heated by the gas to be treated and reach its ignition temperature. To eliminate this risk, it is preferable to use perlite, which is non-flammable and has excellent safety for the human body, as the adsorbent 24a. In this VOC removal device 1, only perlite is used as the adsorbent 24a, and therefore the adsorbent layer 24 is a perlite layer.

[0039] The adsorbent layer 24 may be composed of multiple types of adsorbent materials, and multiple adsorbent layers 24 may be provided in the adsorption processing path 20.

[0040] For forming the adsorption processing channel 20, it is preferable to use a resin pipe such as a polyvinyl chloride pipe, as it has low reactivity with the gas to be processed and excellent insulating properties. In the illustrated example, the plasma processing channel 10 and the adsorption processing channel 20 are arranged in parallel and connected by a curved pipe-shaped connecting channel 21 to make the overall axial length of the VOC removal device 1 compact, but the shape of the connecting channel can be changed as appropriate, such as to a straight pipe. In order to get the plasma-treated gas to reach the adsorption processing channel as quickly as possible, it is preferable to make the path length from the flow path of the plasma processing channel to the adsorbent layer as short as possible. In addition, although the adsorption processing channel 20 is connected to the plasma processing channel 10 by a connecting channel 21 that is separate from the adsorption pipe 22, the pipe for the adsorption processing channel may be formed by a single pipe material without joints.

[0041] A blower (not shown) that sends the gas to be treated into the introduction passage 15 of the plasma treatment passage 10 and discharges it out through the exhaust passage 23 of the adsorption treatment passage 20 may be positioned either upstream or downstream of the VOC removal device 1. By positioning the blower downstream of the VOC removal device 1, even when treating a gas to be treated that contains harmful substances that could adversely affect the surface of the blower blades, the harmful substances are decomposed as the gas to be treated is plasma-generated in the plasma treatment passage 10, thereby suppressing adverse effects on the blower.

[0042] The flow velocity of the gas to be treated in the flow path 14 affects the performance of plasma generation of the gas to be treated, and the flow velocity of the gas to be treated in the adsorbent layer 24 affects the adsorption performance of the adsorbent 24a. Therefore, the output of the blower should be appropriately controlled taking these factors into consideration.

[0043] Furthermore, when a gas to be treated containing water vapor is fed into the plasma processing path 10, the higher the humidity of the gas to be treated, the more likely spark discharge is to occur between the cylindrical electrode 11 and the axial electrode 12 in the flow path 14. Frequent spark discharge in the flow path 14 is undesirable because it easily generates nitrogen oxides due to the excitation of nitrogen and oxygen contained in the gas to be treated. For this reason, it is preferable for the humidity of the gas to be treated fed into the plasma processing path 10 to be low. There is no problem if a dry gas to be treated is fed in, but if the humidity of the gas to be treated is a problem, it is advisable to place a steam-water separator (not shown) upstream of the VOC removal device 1 to maintain the humidity of the gas to be treated fed into the plasma processing path 10 below a predetermined level, for example, below 50%.

[0044] The VOC removal device 1 is as described above, and includes a plasma processing path 10 that generates plasma in the gas to be treated flowing through the flow path 14, and an adsorption processing path 20 that introduces the gas to be treated, from which volatile organic compounds have been decomposed in the plasma processing path 10, and passes it through the adsorption layer 24. By doing so, the volatile organic compounds contained in the gas to be treated are decomposed in the plasma processing path 10, and the gas to be treated, containing the ions and molecules generated by the decomposition, is passed through the adsorption layer of the adsorption processing path 20 and adheres to the adsorbent, thereby suppressing recombination with volatile organic compounds and improving the removal performance of the VOC removal device that decomposes volatile organic compounds with plasma.

[0045] Furthermore, because the adsorbent layer 24 of this VOC removal device 1 is a perlite layer, the adsorbent layer 24 does not ignite even when heated by the gas being treated. Therefore, it can be applied to gases being treated at higher temperatures compared to cases where flammable adsorbents such as activated carbon are used.

[0046] Furthermore, in this VOC removal device 1, the flow path 14 of the plasma processing path 10 is formed between a cylindrical electrode 11 and an axial electrode 12 coaxially arranged inside the cylindrical electrode 11. Plasma is generated in the gas to be processed by applying a voltage between the cylindrical electrode 11 and the axial electrode 12. Since the adsorption processing path 20 is connected to the downstream side of the flow path 14 of the plasma processing path 10, the gas to be processed can be plasma-generated by applying a voltage throughout the entire flow path 14 between the cylindrical electrode 11 and the axial electrode 12 and immediately sent to the adsorption processing path 20. As a result, it becomes easy to capture ions etc. generated by the decomposition of volatile organic compounds in the adsorbent layer 14 before they can recombine with the volatile organic compounds.

[0047] In the first embodiment, an example was shown in which the VOC removal device 1 is equipped with one plasma processing path 10 and one adsorption processing path 20, connected in series. However, it is not essential that the number of plasma processing paths and adsorption processing paths be the same; it is also possible to connect one or more plasma processing paths with multiple or one adsorption processing paths. The flow velocity preferred for plasma generation and the flow velocity preferred for adsorption in the adsorbent layer do not necessarily coincide, and if there is a large difference between these flow velocities, a difference in the number of plasma processing paths and adsorption processing paths can be provided to obtain an appropriate flow velocity in each processing path. Furthermore, in the first embodiment, an example was shown in which the VOC removal device is composed of one set of plasma processing paths and adsorption processing paths. However, the VOC removal device may be configured with multiple sets of plasma processing paths and adsorption processing paths in parallel to increase the processing capacity per unit time in a single VOC removal device. Alternatively, the VOC removal device may be configured with multiple sets of plasma processing paths and adsorption processing paths in series to further increase the VOC removal rate in a single VOC removal device. A second embodiment as an example of this is shown in Figure 2. Here, we will only describe the differences from the first embodiment.

[0048] The VOC removal apparatus according to the second embodiment consists of a plurality of the aforementioned VOC removal apparatuses 1 connected in series. In the illustrated example, the processing path from the introduction passage 31 of the upstreammost VOC removal apparatus 1 to the exhaust passage 32 of the downstreammost VOC removal apparatus 1 is composed of four VOC removal apparatuses 1. These plurality of VOC removal apparatuses 1 are supported by a machine frame 33. By connecting these four VOC removal apparatuses 1 in series, the VOC removal apparatus according to the second embodiment is equipped with four plasma processing passages and adsorption processing passages, and these plasma processing passages and adsorption processing passages are arranged alternately from the upstream side to the downstream side. Therefore, the VOC removal process can be repeated multiple times (four times in the illustrated example) from the introduction passage 31 of the upstreammost plasma processing passage to the exhaust passage 32 of the downstreammost adsorption processing passage, where the gas to be processed containing VOCs is sent, until the VOCs are discharged.

[0049] The VOC removal apparatus according to the second embodiment includes a plurality of plasma processing paths 10 and adsorption processing paths 20. These plasma processing paths 10 and adsorption processing paths 20 are arranged alternately from upstream to downstream. This allows for the removal of volatile organic compounds multiple times between sending the gas to be treated to the upstream plasma processing path 10 and discharging it from the downstream adsorption processing path 20. As a result, the removal of volatile organic compounds from the gas to be treated is gradually advanced, and the final removal rate of volatile organic compounds can be increased.

[0050] Furthermore, the concentration of volatile organic compounds (VOCs) in the gas to be treated is highest in the inlet path 31 of the upstream VOC removal device 1. As the VOC removal device 1 moves further downstream, the VOC concentration of the gas to be treated decreases. This reduces the probability of volatile organic compounds being decomposed in the plasma treatment path, and consequently, the adsorption efficiency in the adsorbent layer of the adsorption treatment path decreases. Therefore, if the number of plasma treatment paths and adsorption treatment paths connected in series is too large, the increase in operating costs may not justify the improvement in VOC removal rate. It is preferable to limit the number of plasma treatment paths and adsorption treatment paths to a saturation point where the removal rate of volatile organic compounds no longer improves significantly. [Examples]

[0051] A test was conducted to evaluate the removal performance of volatile organic compounds using a test unit of the VOC removal device according to the embodiment. The main specifications of the test unit are as follows: • Electrical circuit (high-voltage generator) specifications: Operating voltage 20000V, current 0.0018A, power consumption 36W • Blower specifications: 0.1mm 3 liters / minute • Cylindrical electrodes: 4 x 45mm diameter, 500mm length carbon pipes • Axial electrodes: 4 x φ5mm, 500mm long carbon pipes • Adsorption pipeline: Two PVC pipes, φ50mm in diameter and 500mm in length. • Adsorbent material: Obsidian perlite (400 mesh) • Amount of adsorbent material filling in the adsorbent layer: 100g x 2 bottles • VOC Monitor: Horiba Seisakusho FV-200 (1 unit each for measuring original odor concentration and post-treatment concentration)

[0052] In the test, undiluted toluene was placed in a petri dish, and the concentration of the raw odor was measured using a VOC monitor. The concentration of the raw odor ranged from 1200 ppm to 500 ppm. The treated gas with this concentration of raw odor was then treated using a test VOC removal device. The concentration of volatile organic compounds in the treated gas discharged from the test device was measured using a VOC monitor, and the concentration was found to be between 5 ppm and 12 ppm (removal rate of 99%).

[0053] It should be noted that the embodiments and examples disclosed herein are illustrative and not restrictive in all respects. Therefore, the scope of the present invention is defined by the claims for utility model registration, and all modifications within the meaning and scope equivalent to the claims for utility model registration are intended to be included. [Explanation of Symbols]

[0054] 1 VOC removal equipment 10 Plasma processing path 11. Cylindrical electrode 12 Axial electrode 14 channels 20 Adsorption processing path 22 Adsorption pipe line 24 Adsorbent layer 24a Adsorbent

Claims

1. A plasma processing path that generates plasma in the gas to be processed flowing through the channel, A VOC removal apparatus comprising an adsorption treatment path that introduces a gas to be treated, from which volatile organic compounds have been decomposed in the aforementioned plasma treatment path, and passes it through an adsorption material layer.

2. The VOC removal apparatus according to claim 1, wherein the adsorbent layer is a perlite layer.

3. The VOC removal apparatus according to claim 1 or 2, comprising a plurality of plasma processing paths and adsorption processing paths, wherein these plasma processing paths and adsorption processing paths are alternately arranged from the upstream side to the downstream side.

4. The flow path of the plasma processing path is formed between a cylindrical electrode and an axial electrode arranged coaxially inside the cylindrical electrode. Plasma is generated in the gas to be processed by applying a voltage between the cylindrical electrode and the axial electrode. The VOC removal apparatus according to claim 1 or 2, wherein the adsorption processing path is connected to the downstream side of the flow path of the plasma processing path.

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