Gas treatment apparatus and gas treatment method

Abstract

To provide a gas treatment device capable of more efficiently supplying active oxygen to a gas, and a gas treatment method by active oxygen capable of more efficiently treating a gas by active oxygen.SOLUTION: A gas treatment device includes an active oxygen feed device and a gas flow channel. The active oxygen feed device includes: a housing having at least one opening; a prescribed plasma actuator inside the housing; and a prescribed ozone degradation device. The plasma actuator and the ozone degradation device are arranged so that the induced flow containing the active oxygen flows out from the opening to the outside of the housing. The active oxygen feed device is arranged so as to allow the induced flow containing the active oxygen flowing out from the opening to be introduced to the gas flow channel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to a gas processing apparatus and a gas processing method that utilizes reactive oxygen species. [Background technology]

[0002] Patent Document 1 discloses a nascent oxygen generator comprising: a device body installed in a place where air flows, formed in a cylindrical shape through which a portion of the air passes, and whose inner surface is made of a metal with high ultraviolet reflectivity; an ultraviolet lamp disposed on an axis inside the device body that irradiates ultraviolet light to decompose ozone; and an ozone generator provided upstream of the airflow inside the device body that converts oxygen in the air introduced into the body into ozone by discharge. Paragraph

[0016] of Patent Document 1 states that such a nascent oxygen generator improves the ozone generation capacity and decomposition capacity, generates a large amount of nascent oxygen from ozone, and that this generated nascent oxygen diffuses into the freezer chamber, oxidizing and decomposing malodorous substances in the freezer chamber, thereby deodorizing the freezer chamber. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 06-335518 [Non-patent literature]

[0004] [Non-Patent Document 1] "Effect of magnetic field on photocatalytic reactions by semiconductor titanium oxide thin films," Journal of the Photographic Society of Japan, 2006, 69, 4, 271-275. [Overview of the project] [Problems that the invention aims to solve]

[0005] In the nascent oxygen generator described in Patent Document 1, air introduced into the device from outside comes into contact with active oxygen, so it was thought that it could be used for deodorizing and sterilizing the air outside the device. Therefore, the present inventors considered applying the nascent oxygen generator described in Patent Document 1 to a gas treatment device. However, the ability of this nascent oxygen generator to deodorize and sterilize gases was limited. One aspect of this disclosure aims to provide a gas treatment apparatus and a gas treatment method that can treat gases more effectively using highly oxidizing reactive oxygen species. [Means for solving the problem]

[0006] According to at least one aspect of this disclosure, A gas treatment apparatus comprising an active oxygen supply device and a gas flow path, The reactive oxygen species supply device is A housing having at least one opening, A plasma actuator is located inside the housing, Ozone decomposition device and 、 It is equipped with, The plasma actuator is constructed by stacking a first electrode, a dielectric, and a second electrode in that order. The first electrode is an exposed electrode provided on the first surface, which is one of the surfaces of the dielectric. The plasma actuator generates a dielectric barrier discharge from the first electrode to the second electrode by applying a voltage between the first electrode and the second electrode, and blows out an induced flow containing ozone from the first electrode in a first direction, which is one direction along the surface of the dielectric. The ozone decomposition device generates reactive oxygen species in the induced flow by decomposing the ozone contained in the induced flow, and the induced flow becomes an induced flow containing reactive oxygen species. The plasma actuator and the ozone decomposition apparatus are arranged such that the induced flow containing the active oxygen flows out of the housing through the opening. The active oxygen supply device is arranged such that an induced flow containing the active oxygen is supplied from the opening to the gas flow path. Ori , When viewing the cross-section of the plasma actuator in the thickness direction, In the thickness direction of the plasma actuator, the first electrode and the second electrode are arranged obliquely opposite each other with respect to the dielectric, The first electrode is provided so as to cover a portion of the first surface of the dielectric, The first surface has an exposed portion that is not covered by the first electrode, When the plasma actuator is viewed through from the first electrode side, at least a portion of the exposed part and the second electrode overlap. The induced flow blows out from the edge of the first electrode on the first direction side in the cross-section in the thickness direction, along the exposed portion of the dielectric that overlaps with the second electrode. When the first direction along the surface of the dielectric, which is the direction in which the induced flow is blown out, is defined as the +X direction, the opposite direction to the +X direction is defined as the -X direction, the direction including the +X direction and the -X direction is defined as the X-axis direction, and the direction perpendicular to the X-axis direction and perpendicular to the first surface of the dielectric is defined as the Y-axis direction, the first electrode and the second electrode are provided so as to overlap in the Y-axis direction with the dielectric in between. A gas treatment device is provided, which is characterized by this.

[0007] Also, according to at least one aspect of the present disclosure, Using the above gas treatment apparatus, processing a gas with active oxygen A gas characterized by processing method The law is provided.

Effects of the Invention

[0008] According to one aspect of the present disclosure, a gas treatment device and a gas treatment method capable of more effectively treating a gas using active oxygen with strong oxidizing power can be obtained.

Brief Description of the Drawings

[0009] [Figure 1] Schematic cross-sectional view showing the configuration of a gas treatment device according to one aspect of the present disclosure [Figure 2] Schematic cross-sectional view showing the configuration of a plasma actuator according to one aspect of the present disclosure [Figure 3] Explanatory drawing of a plasma actuator according to one aspect of the present disclosure [Figure 4] Schematic diagram showing the relationship between the first electrode and the second electrode [Figure 5] Schematic diagram of a donut-shaped electrode [Figure 6] Schematic cross-sectional view of a treatment test using a gas treatment device according to one aspect of the present disclosure [Figure 7] Explanatory drawing of the blowing direction vector of the induced flow and the flow direction vector of the gas [Modes for carrying out the invention]

[0010] Furthermore, in this disclosure, unless otherwise specified, the expressions "XX or greater and YY or less" or "XX to YY" that represent a numerical range mean a numerical range that includes the lower and upper limits. When a numerical range is described in steps, the upper and lower limits of each numerical range can be combined in any way.

[0011] Furthermore, the term "bacteria" as the target of "disinfection" in this disclosure refers to microorganisms, and these microorganisms include fungi, bacteria, single-celled algae, viruses, protozoa, etc., as well as animal or plant cells (including stem cells, dedifferentiated cells, and differentiated cells), tissue cultures, and fusion cells obtained by genetic engineering. This includes hybridomas, dedifferentiated cells, and transformants (microorganisms). Examples of viruses include norovirus, rotavirus, influenza virus, adenovirus, coronavirus, measles virus, rubella virus, hepatitis virus, herpesvirus, and HIV virus. Examples of bacteria include staphylococcus, Escherichia coli, Salmonella, Pseudomonas aeruginosa, Vibrio cholerae, Shigella, Anthrax, Mycobacterium tuberculosis, Clostridium botulinum, Clostridium tetani, and Streptococcus. Examples of fungi include dermatophytes, Aspergillus, and Candida. Therefore, "disinfection" as described in this disclosure also includes, for example, the inactivation of viruses. Furthermore, in this disclosure, reactive oxygen species refer to, for example, superoxide (·O2) produced by the decomposition of ozone (O3). - ), including free radicals such as hydroxyl radicals (·OH).

[0012] The following examples illustrate embodiments for implementing this disclosure with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments should be appropriately modified depending on the configuration and various conditions of the members to which the disclosure applies. In other words, this disclosure is not intended to limit its scope to the embodiments described below. Furthermore, in the following explanation, components with the same function may be given the same number in the drawings, and their explanations may be omitted.

[0013] Based on our own investigations, we speculate that the reason why the gas treatment effect of the nascent oxygen generator described in Patent Document 1 is limited is as follows.

[0014] In other words, reactive oxygen species are very unstable, ·O2 - The half-life is 10 -6 The half-life of OH is 10 seconds. -9 It is converted into stable oxygen and water very quickly, in an extremely short time of seconds. In particular, the nascent oxygen generator described in Patent Document 1 is placed where airflow is generated, and a portion of that air passes through the inside of the cylindrical device body. Specifically, in Figure 2 of Patent Document 1, airflow is generated by a refrigerator fan 4 placed in the freezer chamber. In such a situation, even if reactive oxygen species are generated inside the device body, these reactive oxygen species are quickly converted into oxygen and water in the turbulent flow of air flowing in from the outside, and it is thought that the probability of contact with odor components in the air or objects to be disinfected is reduced. Based on these considerations, the inventors conducted further studies with the aim of obtaining a gas treatment apparatus that can more reliably use active oxygen to treat gases and treat gases more effectively. As a result, they found that the gas treatment apparatus described in the following specific embodiments contributes to achieving this objective. However, the gas treatment apparatus described in this disclosure is not limited to the following specific embodiments.

[0015] Hereinafter, a gas treatment apparatus 108 according to one aspect of the present disclosure will be described with reference to Figures 1A and 1B. The gas treatment apparatus 108 according to one aspect of the present disclosure comprises an active oxygen supply device 101 and a gas flow path 109. The reactive oxygen species supply device 101 comprises a housing 107 having at least one opening 106, and inside the housing, an ultraviolet light source 102 as an ozone decomposition device and a plasma actuator (plasma generator) 103. The ultraviolet light source 102, which is an ozone decomposition device, irradiates the induced flow 105 with ultraviolet light, generating reactive oxygen species in the induced flow 105. In Figure 1A, reference numeral 110 denotes the gas to be processed. The gas flow path 109 is the flow path for the gas 110, which is the substance to be processed.

[0016] Furthermore, Figure 2 shows a cross-sectional structure of one embodiment of the plasma actuator 103. The plasma actuator has an exposed electrode (hereinafter also called the "first electrode") 203 with its end face exposed on one surface (hereinafter also called the "first surface") of the dielectric 201, and a second electrode 205 provided on the surface opposite to the first surface (hereinafter also called the "second surface"), so This is a dielectric barrier discharge (DBD) plasma actuator (hereinafter sometimes simply referred to as "DBD-PA"). In Figures 2A and 2B, reference numeral 206 denotes a dielectric substrate for embedding the second electrode 205 within the thickness direction of the plasma actuator to prevent organic flow from the end face of the second electrode. Furthermore, voltage can be applied to the first electrode and the second electrode by a power supply 207.

[0017] In the plasma actuator 103, the first electrode 203 and the second electrode 205, which are positioned with the dielectric 201 in between, are, for example, positioned diagonally opposite each other. By applying a voltage from the power supply 207 between these electrodes (between both electrodes), a dielectric barrier discharge is generated from the first electrode 203 toward the second electrode 205. Then, plasma 202 is generated from the edge 204 of the first electrode 203 toward the direction in which the second electrode extends (direction X in Figure 2), along the exposed portion (the part not covered by the first electrode) 201-1 of the first surface of the dielectric 201. At the same time, an air intake flow is generated from the space inside the container toward the electrode. Electrons in the surface plasma 202 collide with oxygen molecules in the air, dissociating them and producing oxygen atoms. The resulting oxygen atoms collide with undissociated oxygen molecules, generating ozone. Therefore, due to the interaction of the jet-like flow from the surface plasma 202 and the air intake flow, an induced flow 105 containing ozone is generated along the surface of the dielectric 201 from the edge 204 of the first electrode 203. The plasma actuator 103 and the ozone decomposition device 102 are positioned so that the induced flow 105 flows out of the housing 107 through the opening 106.

[0018] In other words, the plasma actuator is constructed by stacking a first electrode 203, a dielectric 201, and a second electrode 205 in that order, with the first electrode 203 being an exposed electrode provided on the first surface of the dielectric 201. The plasma actuator generates a dielectric barrier discharge from the first electrode 203 to the second electrode 205 by applying a voltage between the first electrode 203 and the second electrode 205, and blows out an induced flow from the first electrode 203 in a first direction (direction X in Figure 2), which is one direction along the first surface of the dielectric 201. More specifically, a dielectric barrier discharge is generated from one edge 204 of the first electrode 203 toward the second electrode 205, and an induced flow, which is a unidirectional jet, is ejected from one edge 204 of the first electrode 203 in a first direction (direction of arrow 208 in Figure 2) along the first surface of the dielectric 201. Furthermore, in one cross-section in the thickness direction of the plasma actuator, the second electrode 205 extends in the direction of the induced flow's outflow (first direction).

[0019] More specifically, for example, the plasma actuator has a dielectric 201, and when viewing a cross-section of the plasma actuator in the thickness direction, a first electrode 203 and a second electrode 205 are arranged diagonally opposite each other in the thickness direction of the plasma actuator via the dielectric 201. The first electrode 203 is provided so as to cover a portion of the first surface of the dielectric 201, and the first surface of the dielectric has an exposed portion 201-1 that is not covered by the first electrode 203.

[0020] Figure 2B shows the plasma actuator viewed through one surface of the dielectric. At least a portion of the exposed portion 201-1 overlaps with the second electrode 205, which is shown by the dashed line. Therefore, the overlap is the region formed by the upper, lower, and right edges of the dashed line showing electrode 205 in Figure 2B and the edge portion 204.

[0021] Then, by applying a voltage between the first electrode and the second electrode, the edge 204 on the first direction side of the first electrode 203 in the cross-section in the thickness direction (Figure 2A) overlaps with the second electrode 205. An induced flow containing ozone is generated along the exposed portion of the dielectric material.

[0022] In this disclosure, as shown in Figures 2A and 2B, the first direction along the surface of the dielectric, which is the direction in which the induced flow is blown out, is sometimes referred to as the +X direction. The axis that includes the +X direction is called the X-axis. For example, the X-axis direction includes the +X direction and the opposite direction of the X direction (-X direction). The axis that is perpendicular to the X-axis and perpendicular to the first surface of the dielectric is called the Y-axis. In the Y-axis direction, the direction of the first electrode as seen from the dielectric (for example, the direction approximately vertically upward when the dielectric is held horizontally) is called the Y direction. The axis that is perpendicular to the X direction and along the first surface of the dielectric, i.e., perpendicular to the X-axis and Y-axis, is called the Z-axis.

[0023] The induced flow becomes, for example, a wall jet along the exposed portion 201-1, making it easy to supply ozone to a specific location. The length of the exposed portion 201-1 in the direction of the induced flow (i.e., the length from the edge 204 on the first direction side of the first electrode to the edge of the first surface of the dielectric) is not particularly limited, but is preferably 0.1 to 50 mm, more preferably 0.5 to 20 mm, and even more preferably 1 to 10 mm.

[0024] In other words, in an active oxygen supply device according to one aspect of the present disclosure, an induced flow 105 containing ozone from the plasma actuator 103 flows out of the housing 107 through the opening 106 and is supplied to the gas flow path 109, and an ozone decomposition device 102 decomposes the ozone (for example, by irradiating the induced flow 105 with ultraviolet light from the ultraviolet light source 102) to generate active oxygen in the induced flow 105, thereby actively supplying active oxygen to the gas flow path 109. Therefore, before the generated reactive oxygen species are converted into oxygen and water, the reactive oxygen species can be supplied to the gas flow path 109, thereby processing the gas to be treated. As a result, gas 110 is more reliably processed by reactive oxygen species.

[0025] <Electrodes and Dielectrics> The materials constituting the first and second electrodes are not particularly limited as long as they are highly conductive materials. For example, metals such as copper, aluminum, stainless steel, gold, silver, and platinum, as well as materials plated or vapor-deposited thereon, conductive carbon materials such as carbon black, graphite, and carbon nanotubes, and composite materials obtained by mixing these with resins can be used. The materials constituting the first electrode and the materials constituting the second electrode may be the same or different. Among these, from the viewpoint of avoiding electrode corrosion and ensuring uniform discharge, the material constituting the first electrode is preferably aluminum, stainless steel, or silver. For the same reason, the material constituting the second electrode is also preferably aluminum, stainless steel, or silver.

[0026] Furthermore, the shapes of the first electrode and the second electrode can be flat, wire-shaped, needle-shaped, etc., without any particular limitations. Preferably, the shape of the first electrode is flat. Also preferably, the shape of the second electrode is flat. When at least one of the first electrode and the second electrode is flat, it is preferable that the aspect ratio (length of the long side / length of the short side) of the flat plate is 2 or more. It is also preferable, but not limited to, that at least one of the first and second electrodes has a vertex angle of 45° or less (i.e., the electrode is pointed). Although the drawings show a case where the vertex angles of both the first and second electrodes are 90°, embodiments in which the vertex angle exceeds 45° are also included in this disclosure.

[0027] The dielectric material is not particularly limited as long as it has high electrical insulation properties. For example, resins such as polyimide, polyester, fluororesin, silicone resin, acrylic resin, and phenolic resin, glass, ceramics, and composite materials made by mixing them with resins can be used. Among these, if the dielectric material is ceramics, glass, or polyimide... It is preferable that the dielectric material be a mid-metallic material, and from the viewpoint of strength and insulation, ceramics and silicone resins are preferably used as the dielectric material. In particular, since silicone resin is flexible, it can increase the degree of freedom in the shape of the plasma actuator.

[0028] Plasma is more easily generated when the shortest distance between the first electrode and the second electrode is short. Therefore, it is preferable that the thickness of the dielectric portion of the dielectric 201 that exists between the first electrode 203 and the second electrode 205 is thin enough so as not to cause dielectric breakdown when a voltage is applied to both electrodes. Specifically, for example, when the applied voltage is AC and the maximum and minimum voltage difference of the AC is 0.1kVpp to 100kVpp, the thickness of the dielectric portion can be 10μm to 1000μm, preferably 10μm to 250μm. Furthermore, it is preferable that the shortest distance between the first electrode and the second electrode is 250μm or less.

[0029] <Plasma Actuator> The plasma actuator is not particularly limited as long as it has a dielectric material between a first electrode and a second electrode, and can generate an induced flow, which is a unidirectional jet containing ozone, by applying a voltage between the two electrodes. In a plasma actuator, plasma is more easily generated when the shortest distance between the first and second electrodes is short. Therefore, the dielectric film thickness is preferably as thin as possible, as long as it does not cause electrical breakdown, and can be 10 μm to 1000 μm, preferably 10 μm to 200 μm. Furthermore, the shortest distance between the first and second electrodes is preferably 200 μm or less.

[0030] Figures 3, 4A, and 4B are explanatory diagrams of the overlap between the first electrode 203 and the second electrode 205 of the plasma actuator, which is an ozone generator, and are cross-sectional views of the plasma actuator. The first electrode 203 and the second electrode 205, which are positioned diagonally opposite each other, may have the edge of the first electrode located on the part of the second electrode that is formed on the dielectric when the plasma actuator is viewed from the first electrode (first surface) side. For example, the first electrode and the second electrode may be arranged so as to overlap in the Y-axis direction with the dielectric in between. In this case, it is preferable to prevent dielectric breakdown when a voltage is applied in the part where the first electrode and the second electrode overlap with the dielectric in between.

[0031] Figure 4A shows an configuration in which the first electrode and the second electrode overlap (in the Y-axis direction) with a dielectric material in between. In a cross-section in the thickness direction of the plasma actuator, the edge of the first electrode on the first direction side is denoted as edge A, and the edge of the second electrode on the second direction side (opposite side of the X direction), which is the opposite direction to the first direction, is denoted as edge B. Preferably, edge B is located on the second direction side (opposite side of the X direction) than edge A. Furthermore, when viewing the plasma actuator from the first electrode side, if we define the edge of the first electrode on the first direction side as edge A, and the edge of the second electrode on the second direction side (opposite side of the X direction), which is the opposite direction to the first direction, as edge B, then preferably, edge B is located further to the second direction side (opposite side of the X direction) than edge A. In this way, the first electrode and the second electrode overlap with a dielectric material in between, enabling the generation of a stable plasma and induced flow.

[0032] Furthermore, since the first electrode and the second electrode are positioned diagonally opposite each other via the dielectric 201, edge B is located in the first direction (X direction) more than the edge of the first electrode opposite to edge A. This makes it possible to suppress the generation of induced flow from the edge of the first electrode opposite to edge A.

[0033] Figure 4B shows the first electrode and the second electrode overlapping (in the Y-axis direction) with a dielectric in between. This describes an embodiment that does not exist. In a cross-section in the thickness direction of the plasma actuator, when the edge of the first electrode on the first direction side is defined as edge A, and the edge of the second electrode on the second direction side (opposite side of the X direction), which is in the opposite direction to the first direction, is defined as edge B, preferably, edge B is located on the first direction side (X direction side) than edge A. Furthermore, when viewing the plasma actuator from the first electrode side, if we define edge A as the edge of the first electrode on the first direction side and edge B as the edge of the second electrode on the second direction side (opposite the X direction), which is the opposite direction to the first direction, then preferably, edge B is located on the first direction side (X direction side) than edge A. In this way, when the first electrode and the second electrode do not overlap with the dielectric in between, it is preferable to relatively increase the voltage applied between the two electrodes in order to compensate for the weakening of the electric field due to the relatively larger shortest distance between the electrodes.

[0034] Furthermore, when viewing the plasma actuator from the first electrode side, if we define edge A as the edge of the first electrode on the first direction side and edge B as the edge of the second electrode on the second direction side (opposite the X direction), which is the opposite direction to the first direction, then it is also a preferred embodiment that edge A and edge B coincide in the thickness direction (Y-axis direction) of the dielectric. Moreover, it is also a preferred embodiment that edge A and edge B coincide in the thickness direction (Y-axis direction) of the dielectric in the cross-section of the plasma actuator in the thickness direction. This embodiment, for example, shows an embodiment in which edge A and edge B face each other at the shortest distance with the dielectric in between, and the first electrode and the second electrode neither overlap nor are separated with the dielectric in between. As a result, the energy applied between the two electrodes can be used more efficiently to generate the induced flow.

[0035] The overlap between the edge A of the first electrode and the edge B of the second electrode is preferably -100 μm to +1000 μm in the X-axis direction when viewed from the top of the cross-sectional view, with the overlap length being considered positive (Figure 3). That is, if the case where edge B is located on the opposite side of the induced flow blowout direction from edge A is considered positive, the distance between edge A and edge B in the direction along the dielectric surface (X-axis direction) is preferably -100 μm to +1000 μm, more preferably 0 μm to +200 μm, and even more preferably 0 μm. However, from the viewpoint of processing accuracy in plasma actuator manufacturing, it is difficult to always process the overlap to 0 μm in the Z-axis direction. Therefore, it is customary to provide a positive overlap according to the processing error.

[0036] There are no particular limitations on the thickness of the electrodes for both the first and second electrodes, but they can be between 10 μm and 1000 μm. If the thickness is 10 μm or more, the resistance decreases and plasma generation becomes easier. If the thickness is 1000 μm or less, electric field concentration becomes more likely, which also makes plasma generation easier. The width (x-direction) of both the first and second electrodes is not particularly limited, but it can be 1000 μm or more.

[0037] The shape of the electrode is not particularly limited, but it is preferably rectangular, such as a rectangle or square. A rectangular shape allows for the generation of a uniform induced flow.

[0038] Furthermore, as shown in Figure 5A (perspective view from the first surface side of the dielectric) and Figure 5B (cross-sectional view in the thickness direction of the plasma actuator), the first electrode may be donut-shaped, and the second electrode may be circular or donut-shaped. Even with such electrode configurations, when viewing the cross-section in the thickness direction, the first electrode 203 and the second electrode 205 are positioned diagonally opposite each other in the thickness direction of the plasma actuator via the dielectric 201. The first electrode 203 is provided so as to cover a portion of the first surface of the dielectric 201, and the first surface has an exposed portion 201-1 not covered by the first electrode 203. Furthermore, when viewing the plasma actuator from the first surface side (Figure 5A), at least a portion of the exposed portion 201-1 of the dielectric overlaps with the second electrode 205 (the donut-shaped hole portion of the first electrode). .

[0039] Even in the case of a donut-shaped electrode DBD-PA like this, applying a voltage between the first electrode and the second electrode generates a dielectric barrier discharge from the first electrode to the second electrode, causing an induced flow to be ejected from the first electrode in one direction along the surface of the dielectric. The ejected induced flow collides near the center of the electrode, becoming an axisymmetric jet (3D wall-normal jet) ejected upward in Figure 5B.

[0040] Furthermore, an example of an active oxygen supply device using such a donut-shaped electrode DBD-PA is shown in Figure 5C. In the active oxygen supply device shown in Figure 5C, an induced flow 105 containing ozone is ejected from the inner edge of the donut-shaped first electrode in a first direction, which is one direction along the surface of the dielectric 201, i.e., toward the center. The induced flow 105 then collides with the center of the first electrode, generating an axially symmetric jet 901 containing ozone in a direction perpendicular to the surface 201-1 of the dielectric 201 (vertically downward in Figure 5C). When this axially symmetric jet 901 is excited by an ultraviolet light source 102, the ozone in the axially symmetric jet is decomposed into active oxygen, and the axially symmetric jet containing active oxygen flows out of the housing 107 through the opening 106 and is introduced into the gas flow path. The gas 110 passing through the gas flow path is then treated by the active oxygen in the axially symmetric jet 901 that has flowed out from the opening.

[0041] As shown in Figure 5C, the active oxygen supply device according to this disclosure may have the ozone decomposition device positioned inside the housing so as not to directly excite the gas in the gas flow path 109 provided by the gas treatment device. In such an active oxygen supply device, unlike the case using the active oxygen treatment device shown in Figure 1A, situ generation of active oxygen is unlikely to occur in the gas in the gas flow path. However, the induced flow containing active oxygen flowing out from the opening of the housing actively supplies active oxygen to the gas 110 in the gas flow path, ensuring that the gas 110 is reliably treated.

[0042] Furthermore, the plasma actuator may be a so-called three-electrode plasma actuator, wherein a third electrode is provided downstream of the induced flow from the first electrode and on the first surface of the dielectric 201. In this case, for example, an AC voltage can be applied to the first electrode as an AC electrode, and a DC voltage can be applied to the third electrode as a DC electrode. A sliding discharge can also be generated by applying a negative DC voltage to the DC electrode.

[0043] Furthermore, if the edge of the second electrode is exposed, plasma may be generated from the edge of the second electrode, potentially creating an induced flow in the opposite direction to the induced flow 105 originating from the first electrode. In the gas processing apparatus according to this embodiment, it is preferable to keep the ozone concentration in the internal space of the gas processing apparatus other than the area where the gas to be processed is processed as low as possible. It is also preferable not to generate gas flow within the container that would disturb the flow of the induced flow 105. For this reason, it is preferable not to generate an induced flow originating from the second electrode. Therefore, to prevent plasma generation from the second electrode 205, it is preferable that the second electrode 205 be an embedded electrode. For example, as shown in Figures 2 and 3, the second electrode may be covered with a dielectric such as a dielectric substrate 206, or it may be embedded in a dielectric 201. The second electrode only needs to be embedded to the extent that plasma generation from the edge of the second electrode is prevented. For example, a part of the surface of the second electrode may be exposed, and the exposed surface of the second electrode and the dielectric substrate 206 or dielectric 201 may form the same plane. It is preferable that the edge of the second electrode is covered with the dielectric substrate 206 or dielectric 201. Therefore, for example, the plasma actuator is preferably an SDBD (single dielectric barrier discharge) plasma actuator.

[0044] The plasma actuator is defined as having an edge A in the first electrode as described above. It is preferable that no induced flow is generated from the edges. To this end, edges other than edge A may be covered with a dielectric material. This makes it possible to generate a unidirectional jet even if the first electrode and the second electrode overlap in the Y-axis direction. Alternatively, the shape of the electrodes may be controlled to prevent the generation of induced flow from edges other than edge A in relation to the second electrode. For example, if the electrodes are rectangular, the length of the electrodes in the Z-axis direction (the direction perpendicular to the direction of the induced flow ejection from edge A) may be the same for the first electrode and the second electrode, or the first electrode may be longer. Such an embodiment makes it easier to actively supply the induced flow to the gas flow path.

[0045] The induced flow 105 containing ozone flows in a jet-like flow direction due to surface plasma from the edge 204 of the first electrode 203 along the exposed portion 201-1 of the first surface of the dielectric 201, that is, in the direction from the edge 204 of the first electrode 203 along the exposed portion 201-1 of the first surface of the dielectric. This induced flow is a flow of ozone-containing gas with a velocity of several m / s to several tens of m / s.

[0046] The voltage applied between the first electrode 203 and the second electrode 205 of the plasma actuator is not particularly limited as long as it can generate plasma in the plasma actuator. It may be a DC voltage or an AC voltage, but an AC voltage is preferred. Furthermore, it is also preferred that the voltage be a pulse voltage. Furthermore, the amplitude and frequency of the voltage can be appropriately set to adjust the flow velocity of the induced flow and the ozone concentration in the induced flow. In this case, it is preferable to appropriately select the settings from the viewpoint of generating an ozone concentration in the induced flow that is necessary to produce an effective reactive oxygen concentration or amount of effective reactive oxygen according to the purpose of treatment, and supplying the generated reactive oxygen to the gas to be treated while maintaining an effective reactive oxygen concentration or amount of effective reactive oxygen according to the purpose of treatment.

[0047] For example, the maximum and minimum voltage difference of the AC voltage can be 1kVpp to 100kVpp. Furthermore, the frequency of the voltage can preferably be 1kHz or higher, more preferably 10kHz to 100kHz. When the voltage is an AC voltage, the waveform of the AC voltage is not particularly limited, and a sine wave, square wave, triangular wave, etc., can be used, but a square wave is preferable from the viewpoint of the speed of the voltage rise. The duty cycle of the voltage can also be appropriately selected, but a fast voltage rise is preferred. Preferably, the voltage is applied such that the voltage rise from the bottom to the peak of the wavelength amplitude is 10,000,000 V / sec or more. Furthermore, it is preferable that the value obtained by dividing the amplitude of the voltage applied between the first electrode 203 and the second electrode 205 by the thickness of the dielectric 201 (voltage / thickness) be 10kV / mm or more.

[0048] <Ozone decomposition device> The reactive oxygen species supply device includes an ozone decomposition device 102. The ozone decomposition device decomposes the ozone contained in the induced flow, generating reactive oxygen species in the induced flow. An example of an ozone decomposition device is one that acts on the ozone contained in the induced flow and decomposes it. Preferably, the ozone decomposition device is one that can decompose ozone without disturbing the flow of the induced flow. The ozone decomposition apparatus is preferably at least one device selected from the group consisting of an ultraviolet light source that irradiates the induced flow with ultraviolet light to generate reactive oxygen species in the induced flow, a heating device that heats the induced flow to generate reactive oxygen species in the induced flow, and a humidifying device that humidifies the induced flow to generate reactive oxygen species in the induced flow. The ozone decomposition apparatus may also be a combination of these. For example, it may be a device that heats the induced flow while irradiating it with ultraviolet light, or a device that humidifies the inside of the housing while irradiating the induced flow with ultraviolet light and heating the induced flow. The ozone decomposition apparatus is more preferably an ultraviolet light source. Each device is described below.

[0049] <Ultraviolet light source and ultraviolet light> The ultraviolet light source is not particularly limited as long as it can irradiate ultraviolet light capable of exciting ozone and generating reactive oxygen species. Furthermore, the ultraviolet light source is not particularly limited as long as it has the wavelength and intensity of ultraviolet light necessary to excite ozone and obtain the effective reactive oxygen species concentration or amount of effective reactive oxygen species according to the purpose of the treatment. For example, since the peak value of the light absorption spectrum of ozone is 260 nm, the peak wavelength of the ultraviolet light is preferably 220 nm to 310 nm, more preferably 253 nm to 285 nm, and even more preferably 253 nm to 266 nm. Specific ultraviolet light sources that can be used include low-pressure mercury lamps, which consist of mercury sealed in quartz glass along with an inert gas such as argon or neon, cold cathode ultraviolet lamps (UV-CCL), and ultraviolet LEDs. For low-pressure mercury lamps and cold cathode ultraviolet lamps, the wavelength should be selected from around 254 nm. On the other hand, for ultraviolet LEDs, the wavelength should be selected from around 265 nm, 275 nm, or 280 nm from the standpoint of output performance.

[0050] <Heating device> The heating device is not particularly limited as long as it can provide thermal energy capable of exciting the ozone in the induced flow and generating reactive oxygen species. Since the thermal decomposition of ozone begins at around 100°C, a device capable of heating the induced flow to 120°C is preferred. On the other hand, if the temperature exceeds 120°C, depending on the material of the housing and gas flow path, thermal degradation such as melting or decomposition may occur in the housing and gas flow path, so a temperature of 200°C or lower is preferred.

[0051] The heating device is not particularly limited; for example, ceramic heaters, cartridge heaters, sheathed heaters, electric heaters, oil heaters, etc., can be used. In the case of a device that includes a metal heating element, the heating element is preferably made of a material with excellent oxidation resistance, such as a nichrome alloy or tungsten. A cartridge heater is preferred.

[0052] <humidifier> The humidifier is not particularly limited as long as it humidifies the inside of the enclosure, contains water in the induced flow, and generates reactive oxygen species in the induced flow by decomposing ozone in the induced flow with water. Here, humidification means supplying moisture to the object, and the form of the moisture is not particularly limited, and may be at least one selected from the group consisting of gas, liquid, and solid. Furthermore, any known water can be used as the water supplied, and may also contain substances other than water.

[0053] There are no particular limitations on the type of humidifier; for example, evaporative humidifiers and mist humidifiers can be used. To avoid increasing humidity near the plasma actuator, it is preferable that the humidifier has directionality (hereinafter also simply referred to as directionality) in terms of the direction in which moisture is supplied. By having directionality, the humidifier can efficiently humidify the vicinity of the induced flow and the surface of the workpiece without increasing humidity near the plasma actuator. To give a humidifier directionality, known methods can be suitably used. For example, methods include generating an airflow by installing a fan and transferring moisture in the direction of the airflow, or applying appropriate pressure to the moisture with an air pump and ejecting the moisture in the desired direction. It is preferable to direct the humidifier in the same direction as the induced flow (first direction) so as not to disturb the induced flow.

[0054] <Gas flow path> The gas treatment apparatus 108 includes a gas flow path 109. The gas flow path 109 is not particularly limited as long as the gas 110 to be treated is treated by the active oxygen supply device 101 in the process of flowing through the gas flow path. The size and shape of the gas flow path, its relative position to the active oxygen supply device 101, and the mechanism for flowing the gas are, for example, used to treat the generated active oxygen. The system can be appropriately selected to maintain an effective reactive oxygen species concentration or amount according to the purpose of the experiment, and to actively supply it to the gas flow path.

[0055] The width of the gas flow path 109 (406 in Figure 6) is not particularly limited and can be set as appropriate. Here, the width of the gas flow path 109 refers to the length of the gas flow path in the direction perpendicular to the flat plate when the flat plate is brought into contact with the opening 106 of the active oxygen supply device. For example, in order to achieve sufficient sterilization performance, it is preferable to supply the generated active oxygen to the side of the gas flow path opposite the active oxygen supply device 101, so a short width of the gas flow path is preferable. That is, the width of the gas flow path is preferably 100 mm or less, more preferably 50 mm or less, and even more preferably 12 mm or less. Furthermore, while the width of the gas flow path does not need to be greater than 0 mm, from the viewpoint of increasing the amount of gas processed per unit time, it is preferable that the width of the gas flow path be 3 mm or more, and more preferable that be 6 mm or more.

[0056] The flow velocity of the gas in the gas flow path (i.e., the gas flow rate) is not particularly limited as long as the gas 110, which is the material to be treated, is treated by the active oxygen supply device 101 in the space facing the opening, which is considered to be a location where the active oxygen in the induced flow supplied by the active oxygen generator acts sufficiently. From the viewpoint of sufficient gas treatment, the gas flow rate in the space facing the opening is preferably 2 m / s or less, and more preferably 0.8 m / s or less. Also, it is usually 0 m / s or more, preferably 0.05 m / s or more, and more preferably 0.2 m / s or more. Here, the space facing the opening is the space through which a perpendicular line to the opening surface passes within the gas flow path.

[0057] <Enclosure and opening> The reactive oxygen species supply device comprises a housing 107 having at least one opening 106, an ozone decomposition device 102 located inside the housing, and a plasma actuator 103. The opening is not particularly limited as long as it allows the induced flow 105 generated from the plasma actuator 103 to flow out of the housing 107. The size of the opening, the position of the opening, and the relative position of the opening to the workpiece can be appropriately selected, for example, so that the generated active oxygen can be actively supplied to the gas flow path while maintaining an effective active oxygen concentration or amount of active oxygen according to the purpose of the treatment.

[0058] <Arrangement of plasma actuator, ozone decomposition device, and gas flow path> In the active oxygen supply device 101, the position of the plasma actuator 103 that generates an induced flow containing ozone is not particularly limited, as long as it is positioned so that the induced flow 105, irradiated by ultraviolet light from the ultraviolet light source 102, which is an ozone decomposition device, flows out of the housing through an opening and is supplied to the gas flow path while maintaining an effective active oxygen concentration or amount according to the purpose of treatment. The same applies when the ozone decomposition device is a heating device or a humidifying device. For example, the plasma actuator and the ozone decomposition device should be arranged so that the induced flow 105 containing the generated reactive oxygen species is supplied to the gas flow path via the shortest possible route.

[0059] Furthermore, it is preferable that, for example, the extension line from the edge 204 on the first direction side of the first electrode 203 of the plasma actuator in the direction along the first surface of the dielectric (same as the +X direction) is directed toward the opening. This makes it easier to allow the induced flow to flow out of the housing through the opening and be supplied to the gas flow path.

[0060] Furthermore, in the gas treatment apparatus 108 according to this disclosure, as shown in Figure 7, the blowing direction vector of the induced flow 105 containing active oxygen that flows out of the housing 107 from the opening 106 is... The angle θ between 105a and the flow direction vector of the gas 110 (hereinafter also referred to as the induced flow incidence angle) is not limited as long as the induced flow and the gas are mixed. Therefore, the induced flow incidence angle θ is preferably greater than 0° and 90° or less. In particular, as shown in Figure 7, it is preferable that the blowing direction vector 105a of the induced flow 105 containing active oxygen that flows out of the housing 107 from the opening 106 includes a vector component 105x parallel to the direction of the arrow 110a, which is the flow direction vector of the gas 110. In this case, it is preferable that the induced flow incidence angle θ is greater than 0° and less than 90°, and even more preferably between 30° and 60°. By setting the blowing direction from the opening of the induced flow 105 and the flow direction of the gas 110 to the above-described relationship, the treatment effect of the gas by active oxygen can be significantly improved. The inventors speculate that this is the reason for the following. As described above, in the well-ordered flow of the induced flow supplied from the reactive oxygen species supply device according to this disclosure, reactive oxygen species can maintain their active state for a longer period of time. On the other hand, the gas 110 flowing in the direction of arrow 110a flows in the direction of arrow 110a. Therefore, because the blowing direction vector 105a of the induced flow includes a component 105x parallel to the direction of arrow 110a, which is the flow direction of the gas 110, the well-ordered airflow of the induced flow 105 supplied to the gas 110 is less likely to be disturbed by the gas 110, and thus the gas 110 can be kept in an environment where reactive oxygen species are present for a longer period of time. As a result, it is believed that the gas treatment effect by reactive oxygen species is improved.

[0061] The ozone decomposition apparatus is not particularly limited as long as it is configured to generate active oxygen in the induced flow and to process the gas while maintaining an effective active oxygen concentration or amount according to the purpose of treatment. As described above, an induced flow containing ozone is actively supplied to the gas flow path. Furthermore, if the ozone decomposition device is an ultraviolet light source, reactive oxygen species can be generated in the induced flow by irradiating it with ultraviolet light. Therefore, by irradiating the induced flow with ultraviolet light, ozone is excited, and an induced flow containing reactive oxygen species can be actively supplied to the gas flow path, and the concentration or amount of reactive oxygen species in the gas flow path can be significantly increased. On the other hand, if the ozone decomposition device is configured to process gas passing through a gas flow path via an opening, it can decompose undecomposed ozone present in the induced flow in situ within the region where the gas to be treated is present, thereby generating reactive oxygen species. As a result, the degree and efficiency of the treatment can be further improved.

[0062] The relative positions of the ozone decomposition device and the plasma actuator are not particularly limited, as long as they are positioned such that reactive oxygen species are generated in the induced flow and the gas can be processed while maintaining an effective reactive oxygen species concentration or amount appropriate to the purpose of the treatment. Furthermore, the distance between the ozone decomposition device and the plasma actuator varies depending on the purpose of the treatment, so it cannot be specified in general terms. For example, it is preferable that the distance between the dielectric of the plasma actuator and the surface facing the ozone decomposition device be 10 mm or less, and more preferably 4 mm or less. However, it is not necessary to place the plasma actuator within approximately 10 mm of the ozone decomposition device, and as long as the reactive oxygen species in the induced flow can be brought to an effective concentration according to the purpose of the treatment in relation to the elements that can decompose ozone, such as the irradiance and wavelength of ultraviolet light described later, the distance between the ozone decomposition device and the plasma actuator is not particularly limited. Furthermore, it is also preferable to provide a means of movement to at least one of the ozone decomposition device and the plasma actuator, so that at least one of the ozone decomposition device and the plasma actuator can be moved to ensure a uniform degree of ozone decomposition.

[0063] The relative positions of the reactive oxygen supply device and the gas flow path should be such that at least one of them is positioned so that reactive oxygen is generated in the induced flow, and an induced flow maintaining an effective reactive oxygen concentration or amount according to the purpose of treatment is supplied to the gas flow path.

[0064] Furthermore, if the ozone decomposition device uses an ultraviolet light source, the ultraviolet light source may be positioned so that the ultraviolet light can irradiate the gas to be treated, or it may be positioned so that the ultraviolet light cannot irradiate the gas to be treated. Even if the ultraviolet light from the ultraviolet light source cannot irradiate the gas to be treated, with the treatment device using active oxygen according to this embodiment, the gas to be treated can be treated by being exposed to the active oxygen in the induced flow. Similarly, if the ozone decomposition device is a heating device, the heating device may be positioned in a location where it can heat the gas to be processed, or it may be positioned in a location where it cannot heat the gas to be processed. Furthermore, in gas treatment using only ultraviolet light, only the portion irradiated with ultraviolet light is treated. However, in gas treatment by the active oxygen supply device according to the present disclosure, the gas present at positions where active oxygen can reach can be treated. Therefore, the gas can be treated efficiently.

[0065] On the other hand, as described above, when ultraviolet light from an ultraviolet light source is arranged to irradiate the gas passing through the gas flow path, the undissolved ozone present in the induced flow can be decomposed in situ in the region where the gas to be treated exists, generating active oxygen. As a result, the degree and efficiency of the treatment can be further enhanced. In this case, the illuminance of ultraviolet light at the opening is not particularly limited. For example, also at the opening, it is preferable to set the illuminance of ultraviolet light to an illuminance that can decompose the ozone contained in the induced flow, generate active oxygen in the induced flow, and generate an effective active oxygen concentration or an effective amount of active oxygen according to the purpose of the treatment. Specifically, for example, as a specific example of the illuminance of ultraviolet light at the opening, it is preferably 40 μW / cm 2 or more, more preferably 100 μW / cm 2 or more, still more preferably 400 μW / cm 2 or more, particularly preferably 1000 μW / cm 2 or more. The upper limit of the illuminance is not particularly limited, but for example, it can be 10000 μW / cm 2 or less.

[0066] Furthermore, since the distance between the ozone decomposition device and the opening also varies depending on the purpose of the treatment, it cannot be generally defined. For example, it is preferably 10 mm or less, and more preferably 4 mm or less. However, it is not necessary for the opening to be within about 10 mm from the ozone decomposition device, and the distance between the ultraviolet light source and the opening is not particularly limited as long as the active oxygen in the induced flow can be set to an effective concentration according to the purpose of the treatment in relation to the illuminance of ultraviolet light and the like. Furthermore, in the plasma actuator, the amount of ozone generated per unit time when the ozone in the induced flow is not decomposed by an ozone decomposition device is preferably, for example, 15 μg / min or more. More preferably, it is 30 μg / min or more. There is no particular upper limit to the amount of ozone generated, but for example, it is 1000 μg / min or less. The induced flow velocity should be such that it can actively supply the generated reactive oxygen species to the gas flow path while maintaining an effective reactive oxygen species concentration or amount appropriate to the treatment purpose. For example, as mentioned above, it should be around 0.01 m / s to 100 m / s. As described above, the ozone concentration in the induced flow generated by the plasma actuator, as well as the flow velocity of the induced flow, can be controlled by the thickness and material of the electrodes and dielectric, the type of voltage applied, its amplitude, and frequency.

[0067] The gas treatment apparatus of this disclosure can be used in a wide range of applications that involve supplying active oxygen to a gas to be treated. For example, the gas treatment apparatus of this disclosure can be used for gas sterilization and deodorization applications.

[0068] Furthermore, this disclosure relates to a method for treating a gas with active oxygen, The process includes a step of preparing a gas treatment device equipped with an active oxygen supply device and a gas flow path, The reactive oxygen species supply device is A housing having at least one opening, and inside the housing Placed It is equipped with a plasma actuator and an ozone decomposition device, The plasma actuator is constructed by stacking a first electrode, a dielectric, and a second electrode in that order. The first electrode is an exposed electrode provided on the first surface, which is one of the surfaces of the dielectric. The plasma actuator generates a dielectric barrier discharge from the first electrode to the second electrode by applying a voltage between the first electrode and the second electrode, thereby blowing out an induced flow containing ozone from the first electrode in a first direction, which is one direction along the surface of the dielectric. 、 The ozone decomposition device is Applicable By decomposing the ozone contained in the induced flow, reactive oxygen species are generated in the induced flow. The induced flow becomes an induced flow containing reactive oxygen species, The plasma actuator and the ozone decomposition apparatus are arranged such that the induced flow containing the active oxygen flows out of the housing through the opening. The reactive oxygen species supply device is The reactive oxygen species The present invention provides a gas treatment method using active oxygen, characterized in that the induced flow is arranged to be supplied from the opening into the gas flow path.

[0069] In this disclosure, "effective reactive oxygen concentration or amount of effective reactive oxygen" refers to the amount of reactive oxygen to achieve a specific purpose for the object to be treated, such as sterilization or deodorization. This can be appropriately adjusted according to the purpose using elements that can decompose ozone, such as the electrodes constituting the plasma actuator, the thickness and material of the dielectric, the type, amplitude and frequency of the applied voltage, the irradiance and irradiation time of ultraviolet light, and the induced flow incidence angle. [Examples]

[0070] The present disclosure will be described in further detail below using examples and comparative examples, but the embodiments of the present disclosure are not limited thereto.

[0071] <Example 1> 1. Fabrication of a reactive oxygen species supply device A first electrode was formed by attaching a piece of aluminum foil measuring 2.5 mm in length, 15 mm in width, and 100 μm in thickness to the first surface of a glass plate (5 mm in length, 18 mm in width (in the depth direction of the paper in Figure 1A), which served as a dielectric, using adhesive tape. A second electrode was also formed by attaching a piece of aluminum foil measuring 3 mm in length, 15 mm in width, and 100 μm in thickness to the second surface of the same glass plate using adhesive tape, so as to be diagonally opposite to the aluminum foil attached to the first surface. Furthermore, the second surface, including the second electrode, was covered with polyimide tape. In this way, a plasma actuator was fabricated in which the first and second electrodes overlapped over a width of 200 μm, with the dielectric (glass plate) in between. Two of these plasma actuators were prepared.

[0072] Next, as the housing 107 of the active oxygen supply device 101, a case made of ABS resin was prepared, with a height of 25 mm, a width of 20 mm, a length of 170 mm, and a thickness of 2 mm, and a roughly trapezoidal cross-sectional shape in the short direction (cross-section cut at AA' in Figure 1B) as shown in Figure 1A. Figure 1B is a view of the case from the opening 106. The case has a rectangular opening 106 with a width of 7 mm and a length of 15 mm, symmetrically on both sides with respect to the center of the longitudinal length of 170 mm (a dashed line at AA' in Figure 1B). Then, the two plasma actuators 103 that were previously manufactured were fixed to the slanted side portion of the housing 107 in Figure 1A so that the induced flow incidence angle θ was 45°. The mounting position of the plasma actuators 103 (dashed line portion in Figure 1B) as viewed from the bottom surface direction of the housing (Figure 1B) is the center line of the housing length of 170 mm (a dashed line at AA') and the opening The center line of the mouth section was fixed in place so that it aligned with the center of the plasma actuator.

[0073] Furthermore, an ozone decomposition device, an ultraviolet lamp 102 (cold cathode ultraviolet lamp, product name: UW / 9F89 / 9, manufactured by Stanley Electric Co., Ltd., cylindrical with a diameter of 9 mm, peak wavelength = 254 nm), was placed inside the housing. The distance between the ultraviolet lamp 102 and the exposed portion 201-1 of the first surface of the dielectric 201 of the plasma actuator (reference numeral 403 in Figure 6) was 2 mm, and the distance between the ultraviolet light source and the side of the flat plate facing the ultraviolet light source (reference numeral 401 in Figure 6) was 3 mm when the flat plate was brought into contact with the opening 106 of the housing 107. In this way, the active oxygen supply device according to this embodiment was fabricated.

[0074] An illuminance meter (product name: USR-45D spectroradiometer, manufactured by Ushio Inc.) was placed at the opening 106, which serves as the supply port for reactive oxygen species in the reactive oxygen species supply device 101, and the ultraviolet irradiance was measured. From the integral value of the spectrum, the value was 1370 μW / cm². 2 At this time, the plasma actuator was not powered on to avoid being affected by the shielding effect of ultraviolet rays by ozone generated from the plasma actuator.

[0075] Next, in order to calculate the amount of ozone generated from the plasma actuator 103, the active oxygen supply device 101 was placed in a sealed container (not shown) with a volume of 1 liter. The sealed container was provided with a hole that could be sealed with a rubber stopper, allowing the gas inside to be drawn out with a syringe through the hole. An AC voltage with a sine wave waveform of 2.4 kVpp and a frequency of 80 kHz was applied to the plasma actuator 103, and after 1 minute, 100 ml of gas was collected from the sealed container. The collected gas was drawn into an ozone detection tube (product name: 182SB, manufactured by Komei Rikagaku Kogyo Co., Ltd.), and the measured ozone concentration (PPM) contained in the induced flow from the plasma actuator 103 was measured. Using the measured ozone concentration value, the amount of ozone generated per unit time was calculated using the following formula.

[0076]

number

[0077] As a result, the ozone generation rate per unit time was 39 μg / min. At this time, the UV light source was not powered on to avoid the decomposition of ozone by ultraviolet radiation. Finally, the amount of ozone generated was measured when both the plasma actuator 103 and the ultraviolet lamp 102 were operating. The operating conditions for the plasma actuator 103 were such that it generates 39 μg / min of ozone when only the plasma actuator 103 is operating. The operating conditions for the ultraviolet lamp 102 were such that it generates 1370 μW / cm² when only the ultraviolet lamp 102 is operating. 2 These are the conditions for achieving the specified illuminance. As a result, the amount of ozone generated when both the plasma actuator 103 and the ultraviolet lamp 102 were operating was 8 μg / min. The decrease of 31 μg / min from 39 μg / min is considered to be the amount of ozone converted into reactive oxygen species.

[0078] 2. Fabrication of gas treatment device and test mechanism The gas treatment apparatus 108 used in this embodiment uses the active oxygen generator 101 prepared above. It is equipped with these features. Figure 6 illustrates the configuration of the test mechanism using the gas treatment device according to this embodiment. Of the gas treatment devices, the gas flow paths 109, excluding the active oxygen generator, were made using acrylic components containing acrylic resin. A mechanism for the evaluation test described later was also fabricated. As shown in Figure 6, the test mechanism consists of a gas treatment device 108, a bacteria-containing gas preparation unit 407, and a bacteria recovery unit 408. The bacteria-containing gas preparation unit 407, the gas treatment device 109, and the bacteria recovery unit 408 were installed in this order in a continuous sequence. The outer surfaces of the bacteria-containing gas preparation unit 407 and the bacteria recovery unit 408 were also fabricated using acrylic material containing acrylic resin, similar to the gas flow path. Five-mm diameter holes were made in the four adjacent walls of the bottom surface of the bacterial collection section 408, and a water trap 411 and a suction pump 412 (mini pump MP-2N, manufactured by Shibata Scientific, with a flow meter to allow for variable flow rate) were connected in this order via a resin pipe 409. During the test, the gas was circulated by operating the suction pump. The distance 406, which corresponds to the height of the gas flow path from the opening 106 in the gas flow path 109 to the wall surface opposite it, was set as shown in Figure 6. The distance 406 was set to 6 mm. The gas flow velocity is the gas flow velocity in the space facing the opening, which is considered to be the area where the reactive oxygen species generated by the reactive oxygen species generator are expected to act fully. The space facing the opening is the space through which a perpendicular line to the opening surface passes within the gas flow path. The gas flow velocity was measured by installing an opening / closing window 416 adjacent to the bacteria collection section 409 in the space facing the opening, and inserting the detection rod of an anemometer (Kanomax Anemomaster Anemometer MODEL6006) into it.

[0079] 3. Evaluation 3-1. Confirmation test for reactive oxygen species (See Non-Patent Document 1) The presence or absence of reactive oxygen species in the induced flow flowing out from the opening was confirmed using decolorization of methylene blue. Methylene blue is a crystalline powder with a blue luster that is soluble in water and ethanol, and is used as a stain or indicator in solution. Methylene blue decomposes upon contact with reactive oxygen species, losing its blue color. Therefore, the presence or absence of reactive oxygen species in the induced flow can be confirmed by the decolorization (disappearance of blue color) of methylene blue. Specifically, the following operations were performed. A 0.01% by mass methylene blue aqueous solution was prepared by mixing methylene blue (manufactured by Kanto Chemical, special grade) with distilled water. 15 ml of this methylene blue aqueous solution was placed in a petri dish (Eiken Kagaku AB4000, cylindrical, 88 mm diameter). The device was then positioned on the petri dish such that the distance between the liquid surface of the methylene blue aqueous solution and the ultraviolet lamp device was 6 mm. In order to create this relationship between the opening, the petri dish, and the liquid surface, the device configuration was adjusted as needed in a manner that would not affect this verification test. Next, an AC voltage with a sine wave waveform of 2.4 kVpp and a frequency of 80 kHz was applied between both electrodes of the plasma actuator, and an ultraviolet lamp was turned on. The induced flow flowing out of the opening was then supplied to the liquid surface for 30 minutes. The ultraviolet lamp was set to an illuminance of 1370 μW / cm² measured on the exposed surface of the dielectric of the plasma actuator facing the ultraviolet lamp, without power being supplied to the plasma actuator. 2 I adjusted it so that it would be as follows. After induced flow irradiation, the methylene blue aqueous solution is transferred to a cell and measured using a spectrophotometer (Jasco). The change in light absorption of methylene blue was measured using V-570. Since methylene blue has strong absorption at a wavelength of 664 nm, the degree of decolorization of methylene blue can be calculated from the change in absorbance at this wavelength. In this test, first, distilled water alone was placed in the reference cell, and a 0.01% methylene blue aqueous solution before induced flow irradiation was placed in the sample cell and measured. The absorbance was 2.32 Abs. On the other hand, the absorbance of the methylene blue aqueous solution after induced flow irradiation was 0.21 Abs. Therefore, the rate of decrease in absorbance was 91% ((2.32 - 0.21)). It was (2.32) × 100).

[0080] 3-2. Treatment (disinfection) test A sterilization test for E. coli was conducted using the gas treatment device 108 according to the following procedure. All equipment used in this sterilization test was sterilized using autoclave-assisted steam sterilization. The sterilization test was also conducted in a clean bench. First, E. coli (product name "KWIK-STIK (Escherichia coli ATCC8739)", Microbiologics) was placed in an Erlenmeyer flask containing LB medium (a mixture of 2g tryptone (product name "Bacto Tryptone", Life Technologies Japan), 1g yeast extract (product name "Yeast Extract", Life Technologies Japan), and 1g sodium chloride (product name "Special Grade Sodium Chloride", Kishida Chemical Co., Ltd.) with 200mL of distilled water). Next, the Erlenmeyer flask was cultured at 37°C for 48 hours at 80rpm using a shaking incubator (Takasaki Scientific Instruments Co., Ltd. TA-25R-3F) to obtain an E. coli solution. The number of viable cells in the obtained E. coli solution was 9.2 × 10⁶. 9 The value was (CFU / mL).

[0081] 20 mL of the prepared E. coli solution was placed in a petri dish, and the petri dish was placed on the bottom surface of the bacterial gas preparation unit 407 to create a petri dish 414 containing the E. coli solution. As a method for generating gas containing E. coli, a method of forming a bacterial solution mist in the bacterial gas preparation unit 407 was adopted. That is, a method of forming a bacterial solution mist using an ultrasonic atomizer (manufactured by REN HE) was used. The ultrasonic atomizer consists of a control circuit board (not shown) and a transducer 413 connected to the circuit board by wiring. The transducer is made of ABS resin, silicone resin, and ceramic material, and the ceramic material is in the form of a circular sheet with a diameter of 16 mm and countless micropores of 5 μm are provided from the top surface to the bottom surface. Because this ceramic material has piezoelectric properties, ultrasonic vibrations are generated in the transducer when voltage is applied. When the bottom surface of the transducer is placed on the surface of the bacterial solution and ultrasonic waves are generated, the bacterial solution passes through the micropores as if being drawn up, forming fine droplets, and a mist is ejected from the top surface of the transducer. By operating the suction pump connected to the bacterial collection unit 408 via the resin pipe 409, negative pressure is created inside the bacterial collection unit 408, allowing the bacterial liquid mist to be transferred to the bacterial collection unit 408. At this time, by providing a hole 415 in the bacterial-containing gas preparation unit 415, outside air can be drawn into the bacterial-containing gas preparation unit 407 through the hole 415, allowing the bacterial liquid mist to be transferred.

[0082] A stamp culture medium 410 (Petan Check 25 PT1025, manufactured by Eiken Kasei Co., Ltd.) was placed at the bottom of the bacterial recovery section 408. Next, the ultrasonic atomizer, suction pump, and active oxygen supply device were activated simultaneously, and this point was defined as time 0 seconds. A DC voltage of 5V was applied to the ultrasonic atomizer. The suction volume of the suction pump was set to 2.5 L / min. The active oxygen supply device 101 was activated, and a voltage with a sine wave waveform of amplitude 2.4 kV and frequency 80 kHz was applied to the plasma actuator. The illuminance of the ultraviolet lamp, measured without powering on the plasma actuator, was 1370 μW / cm². 2 By irradiating the gas channel with ultraviolet light in such a manner, the gas containing bacteria passing through the gas channel was treated with an induced flow containing reactive oxygen species. The applied voltage to the plasma actuator and ultraviolet light source of the reactive oxygen species supply device was set to the same values ​​as in the reactive oxygen species confirmation test in 3-1. This test was conducted for 15 seconds, and then terminated by simultaneously stopping the pump, reactive oxygen species supply device, and ultrasonic atomizer. The gas flow velocity during this test was 0.46 m / sec. After the test was completed, the stamp culture medium from bacterial recovery unit 408 was placed in a constant temperature bath (product name: IS600; manufactured by Yamato Scientific Co., Ltd.) and incubated at 37°C for 24 hours to obtain sample No. 1. The number of colonies that grew was counted to obtain the number of viable bacteria remaining after sterilization treatment. As a result, the number of viable bacteria in sample No. 1 was 0 (CFU).

[0083] Next, a culture test was performed in the same manner as for sample No. 1, except that treatment with an active oxygen supply device was not performed, to obtain sample No. C1. The number of colonies was then counted to calculate the number of viable cells. As a result, the number of viable cells in sample No. C1 was 197 (CFU). Therefore, the rate of E. coli removal by the reactive oxygen species supply device in this test was 100.0% (=(197-0) / 197).

[0084] <Examples 2-5> Examples 2-5 were created and evaluated in the same manner as in Example 1, except that the irradiance and wavelength of ultraviolet light, and the thickness and material of the dielectric in the plasma actuator were changed as shown in Table 1. The results are shown in Table 1. In Example 5, an ultraviolet LED (peak wavelength 280 nm) was used as the ultraviolet light source.

[0085] <Example 6> A gas treatment apparatus was fabricated in the same manner as in Example 1, except that the height of the gas flow path was changed as shown in Table 1. The apparatus was then evaluated and designated as Example 6. The results are shown in Table 1. In Example 6, when performing the 3-1. Active Oxygen Confirmation Test, the distance between the top of the petri dish and the opening was set to 10 mm. This was to accommodate the change in the height of the gas flow path, which is a condition for the 3-2. Treatment (Disinfection) Test.

[0086] Although the flow path for the bacteria-containing gas widened and the distance from the opening increased, the gas's sterilization capacity remained sufficient.

[0087] <Comparative Examples 1-3> Comparative Examples 1 to 3 were configured as follows, but otherwise the conditions were the same as those for Example 1. Comparative Example 1: No voltage was applied to the plasma actuator, and no ultraviolet light was irradiated. Comparative Example 2: A voltage was applied to the plasma actuator, but ultraviolet light was not irradiated. Comparative Example 3: The plasma actuator was irradiated with ultraviolet light without applying voltage.

[0088] [Table 1] In the table, PA represents a plasma actuator, and UV represents ultraviolet light. Ozone concentration indicates the ozone concentration when the ultraviolet light source is not powered on, and UV irradiance indicates the ultraviolet irradiance when only the ultraviolet light source is operating.

[0089] As shown in Comparative Example 3, decolorization of methylene blue did not occur with ultraviolet light. Also, as shown in Comparative Example 2, some decolorization of methylene blue was observed when ozone was generated. Furthermore, when both ozone generation and ultraviolet irradiation were performed, the decolorization of methylene blue progressed further due to the high reactivity of reactive oxygen species. In Comparative Example 1, neither the plasma actuator nor the reactive oxygen species are operating, therefore ultraviolet light and Neither ozone nor reactive oxygen species had any sterilization effect. In Comparative Example 2, some sterilization effect was observed with ozone, but it was not as effective as in Examples 1-6. The slight decolorization of methylene blue observed in Comparative Example 2 is thought to have been caused by ozone, not by reactive oxygen species. In Comparative Example 3, some sterilization effect was observed with ultraviolet light, but it was not as effective as in Examples 1-6, and the gas treatment device was insufficient. [Explanation of symbols]

[0090] 101: Reactive oxygen supply device (treatment device using reactive oxygen), 102: Ultraviolet light source (ultraviolet lamp), 103: Plasma actuator, 105: Induced flow, 106: Opening, 107: Housing, 108: Gas treatment device, 109: Gas flow path, 110: Gas, 110a: Gas flow direction vector

Claims

1. A gas treatment apparatus comprising an active oxygen supply device and a gas flow path, The reactive oxygen species supply device is A housing having at least one opening, A plasma actuator is located inside the housing, Ozone decomposition device, It is equipped with, The plasma actuator is constructed by stacking a first electrode, a dielectric, and a second electrode in this order. The first electrode is an exposed electrode provided on the first surface, which is one of the surfaces of the dielectric. The plasma actuator generates a dielectric barrier discharge from the first electrode to the second electrode by applying a voltage between the first electrode and the second electrode, and blows out an induced flow containing ozone from the first electrode in a first direction, which is one direction along the surface of the dielectric. The ozone decomposition device generates reactive oxygen species in the induced flow by decomposing the ozone contained in the induced flow, and the induced flow becomes an induced flow containing reactive oxygen species. The plasma actuator and the ozone decomposition apparatus are arranged such that the induced flow containing the active oxygen flows out of the housing through the opening. The reactive oxygen supply device is arranged such that an induced flow containing the reactive oxygen is supplied from the opening into the gas flow path. When viewing the cross-section of the plasma actuator in the thickness direction, In the thickness direction of the plasma actuator, the first electrode and the second electrode are arranged obliquely opposite each other with respect to the dielectric, The first electrode is provided so as to cover a portion of the first surface of the dielectric, The first surface has an exposed portion that is not covered by the first electrode, When the plasma actuator is viewed through from the first electrode side, at least a portion of the exposed part and the second electrode overlap. The induced flow blows out from the edge of the first electrode on the first direction side in the cross-section in the thickness direction, along the exposed portion of the dielectric that overlaps with the second electrode. The first direction along the surface of the dielectric, which is the direction in which the induced flow is blown out, is defined as the +X direction, When the opposite direction to the +X direction is defined as the -X direction, the direction including the +X direction and the -X direction is defined as the X-axis direction, and the direction perpendicular to the X-axis direction and perpendicular to the first surface of the dielectric is defined as the Y-axis direction, the first electrode and the second electrode are provided so as to overlap in the Y-axis direction with the dielectric in between. A gas treatment apparatus characterized by the following:

2. The gas apparatus according to claim 1, wherein the amount of ozone generated per unit time in the plasma actuator, when the ozone in the induced flow is not decomposed by the ozone decomposition device, is 15 μg / min or more.

3. The gas apparatus according to claim 1 or 2, wherein the induced flow containing the active oxygen that flows out of the housing from the opening has a blowing direction vector that has a component parallel to the flow direction of the gas in the gas flow path.

4. The gas apparatus according to any one of claims 1 to 3, wherein the distance of the dielectric of the plasma actuator from the surface facing the ozone decomposition apparatus is 10 mm or less.

5. The gas processing apparatus according to any one of claims 1 to 4, wherein the ozone decomposition apparatus is arranged to process the gas passing through the gas flow path via the opening.

6. The gas apparatus according to any one of claims 1 to 5, wherein the width of the gas flow path is 12 mm or less.

7. The ozone decomposition apparatus is An ultraviolet light source that irradiates the induced flow with ultraviolet light to generate the reactive oxygen species in the induced flow, A heating device that heats the induced flow and generates the active oxygen in the induced flow, and A humidifier that humidifies the induced flow and generates the active oxygen in the induced flow. It is at least one device selected from the group consisting of, A gas treatment apparatus according to any one of claims 1 to 6.

8. The ozone decomposition apparatus is an ultraviolet light source, The gas apparatus according to claim 7, wherein the peak wavelength of ultraviolet light emitted by the ultraviolet light source is 220 nm to 310 nm.

9. The ozone decomposition apparatus is an ultraviolet light source, The irradiance of ultraviolet light at the aforementioned opening is 40 μW / cm². ２ The gas apparatus according to claim 7 or 8.

10. A gas treatment method characterized by treating a gas with active oxygen using a gas treatment apparatus according to any one of claims 1 to 9.

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