JP2010234260A - Gas treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continue the treatment of treatment object gas while suppressing the generation of abnormal discharge and to prevent untreated gas from remaining. <P>SOLUTION: A high voltage application means 20 is set. The first electrode 8 of a honeycomb structure 4 is connected to the positive voltage supply terminal T1 of the high voltage application means 20, and the second electrode 9 of the honeycomb structure 4 is connected to the negative voltage supply terminal T2 of the high voltage application means 20. Driving pulses PS1 and PS2 are output to integrated circuits IC1 and IC2 for switching by a control part CNT, and a positive voltage +V1 rising in a positive direction from a ground potential to the first electrode 8 and a negative voltage -V2 falling in a negative direction from the ground potential to the second electrode 9 are alternately switched and applied. An abnormal discharge detection part 21 is set, and in the case of detecting the generation of the abnormal discharge between the first electrode 8 and the second electrode 9, the break period of a high voltage to the first electrode 8 and the second electrode 9 is automatically adjusted corresponding to the generation amount of the abnormal discharge. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gas processing apparatus that purifies harmful gas contained in a gas to be processed.

  2. Description of the Related Art Conventionally, a technique for purifying harmful gas contained in exhaust gas by creating a plasma state by performing high voltage discharge in the exhaust gas is known. In recent years, this technology is being applied to a purification device for purifying factory exhaust and an air purifier for purifying indoor air for the purpose of deodorization.

  Plasma that is in a thermally non-equilibrium state, that is, in which the electron temperature is much higher than the temperature of the gas or ion (non-equilibrium plasma (hereinafter simply referred to as plasma)) is the ion or radical produced by electron collision. Promotes a chemical reaction that does not occur at room temperature, and is considered useful in hazardous gas treatment as a medium that can efficiently remove or decompose harmful gases. The key to practical use is to improve the energy efficiency during processing and to convert it into a completely safe product after processing with plasma.

In general, plasma at atmospheric pressure is generated by gas discharge or electron beam. There are nitrogen oxides (NOx), sulfur oxides (SOx), chlorofluorocarbons, CO ₂ , volatile organic solvents (VOC), etc. that are currently being considered for application. Above all, NOx is contained in the exhaust gas of a car, so that it needs to be put into practical use immediately.

The phenomenon in discharge plasma (plasma generated by gas discharge) in NOx removal is that ions and radicals generated primarily by electron collision cause an initial reaction, and N ₂ , H ₂ O, It is thought that it is converted into each particle such as NH ₄ NO ₃ .

Further, when the harmful gas is, for example, acetaldehyde or formaldehyde, the harmful gas is converted into CO ₂ and H ₂ O by passing plasma. In this case, ozone (O ₃ ) is generated as a by-product.

  FIG. 14 illustrates a main part of a conventional gas processing apparatus using discharge plasma (see, for example, Patent Document 1). In the figure, reference numeral 1 denotes a duct (ventilation path) through which a gas to be treated (air containing toxic gas) GS flows. Inside the duct 1, the discharge electrode 2 and the earth are connected along the direction from the inlet to the outlet of the duct 1. The electrodes 3 are alternately arranged, and a honeycomb structure 4 having a large number of through holes 4 a called cells is disposed between the electrodes 2 and 3. The through holes 4a are provided in the honeycomb structure 4 in a honeycomb shape. Reference numeral 5 denotes a high voltage power source. The honeycomb structure 4 is formed of an insulator such as ceramics, and Patent Document 2 also has an example of its use.

  The discharge electrode 2 is formed of a metal mesh, a fine wire, a needle-like body, or the like. Each discharge electrode 2 is connected to the + pole of the high voltage power supply 5 by a conducting wire 6. The ground electrode 3 is formed of a metallic mesh or the like. Each ground electrode 3 is connected to the negative pole of the high voltage power supply 5 by a conducting wire 7.

  In this gas processing apparatus, the gas GS to be processed is caused to flow through the duct 1, and a high voltage (several kV to several tens kV) from the high voltage power supply 5 is applied between the discharge electrode 2 and the ground electrode 3. Thereby, plasma is generated in the through-holes 4a of the honeycomb structures 4, and harmful gases contained in the processing target gas GS are decomposed into harmless substances by ions and radicals generated in the plasma.

  In this gas processing apparatus, when attention is paid to moisture (humidity) in the processing target gas GS, each of the processing target gases GS flows from the upstream side honeycomb structure 4 toward the downstream side honeycomb structure 4 in each process. Although the treatment is performed by the plasma discharge generated in the honeycomb structure 4, the moisture contained in the treatment target gas GS is consumed every time the treatment is received, so that the humidity of the treatment target gas GS decreases from the upstream side to the downstream side. It becomes a state. In addition, the plasma generation state inside the honeycomb structure 4 is more actively performed as the moisture in the gas GS to be processed increases, and has a characteristic of being suppressed when the moisture decreases.

  Here, if there is too much moisture in the gas GS to be processed, excessive plasma may be generated, causing abnormal discharge. When abnormal discharge occurs, the honeycomb structure 4 itself is damaged and damaged. Therefore, Patent Documents 3 and 4 show configurations in which the occurrence of abnormal discharge is detected and application of a high voltage is cut off.

JP 2000-140562 A JP 2001-276561 A JP 2008-245739 A JP-A-9-99254

  However, in the configurations shown in Patent Documents 3 and 4, when the occurrence of abnormal discharge is detected, the application of high voltage is interrupted, so that the amount of plasma generated becomes 0 and the processing of the processing target gas is continued. There is a problem that untreated gas remains and untreated gas remains.

  The present invention has been made to solve such a problem, and the object of the present invention is to continue the processing of the gas to be processed while suppressing the occurrence of abnormal discharge so that no untreated gas remains. An object of the present invention is to provide a gas processing apparatus that can be used.

  In order to achieve such an object, the present invention provides a porous body that has a large number of through-holes that are arranged in a ventilation path and through which a gas to be processed flowing in the ventilation path passes, and one and the other outside the porous body. First and second electrodes disposed on the first electrode, high voltage applying means for applying a high voltage between the first electrode and the second electrode to generate plasma in the through hole of the porous body, An abnormal discharge detecting means for detecting that an abnormal discharge has occurred between the electrode and the second electrode, and plasma generated in the through hole of the porous body when the abnormal discharge is detected by the abnormal discharge detecting means And a control means for controlling the application of a high voltage between the first electrode and the second electrode from the high voltage application means.

  According to this invention, the porous body is disposed in the ventilation path, the first electrode and the second electrode are disposed on one and the other outside of the porous body, and the first electrode and the second electrode A high voltage is applied between them, and plasma is generated in the through holes of the porous body. When an abnormal discharge occurs between the first electrode and the second electrode during the application of the high voltage, the control means causes the first so as to reduce the amount of plasma generated in the through hole of the porous body. The application of a high voltage between the first electrode and the second electrode is controlled.

  Further, the present invention provides a plurality of porous bodies that are arranged at intervals in the ventilation path and have a large number of through holes through which the processing target gas flowing in the ventilation path passes, and of the processing target gas among the plurality of porous bodies. An upstream electrode disposed on the upstream side of the porous body disposed on the most upstream side in the passage direction and a downstream side of the porous body disposed on the most downstream side in the passage direction of the gas to be processed among the plurality of porous bodies. The downstream electrode, one of the upstream electrode and the downstream electrode is the first electrode, the other is the second electrode, and a high voltage is applied between the first electrode and the second electrode to High voltage applying means for generating plasma in the space between the through hole and the porous body, abnormal discharge detecting means for detecting that abnormal discharge has occurred between the first electrode and the second electrode, and the abnormal discharge When the abnormal discharge is detected by the detection means, And a control means for controlling the application of a high voltage between the first electrode and the second electrode from the high voltage application means so as to reduce the amount of plasma generated in the space between the porous bodies. It is provided.

  According to the present invention, the porous body is disposed with a gap in the ventilation path, the upstream electrode is disposed on the upstream side of the porous body disposed on the most upstream side among the plurality of porous bodies, and disposed on the most downstream side. A downstream electrode is disposed on the downstream side of the porous body, and one of the upstream electrode and the downstream electrode is a first electrode and the other is a second electrode, and between the first electrode and the second electrode. Is applied with a high voltage, and plasma is generated in the through holes of the porous body and the space between the porous bodies. When an abnormal discharge occurs between the first electrode and the second electrode during the application of the high voltage, the control means reduces the amount of plasma generated in the through hole of the porous body and the space between the porous bodies. In this manner, application of a high voltage between the first electrode and the second electrode is controlled.

  In the present invention, plasma is generated not only in the through holes of the porous body but also in the space (air layer) between the porous bodies. For this reason, in addition to the molecular decomposition effect of the harmful gas in the through hole, the molecular decomposition effect of the harmful gas in the space between the porous bodies is added. Further, the molecular decomposition effect in the through hole and the space between the porous bodies are added. Due to the synergistic effect with the molecular decomposition effect, decomposition of harmful gases into harmless substances is promoted. A large amount of uniform plasma is generated in the space between the porous bodies.

Further, in the present invention, since an air layer is provided between the porous bodies, the impedance between the upstream electrode and the downstream electrode is stabilized, and the change of the flowing current with respect to the impedance change due to moisture absorption / drying of the porous body. This eliminates the need to use a special high-voltage power supply specially designed.
In the present invention, the electrodes need only be two electrodes, an upstream electrode and a downstream electrode, and it is not necessary to arrange electrodes for each porous body, the number of parts is reduced, the structure is simplified, and the number of assembly steps is also reduced. Less is enough.

  Further, the present invention provides a plurality of porous bodies that are arranged at intervals in the ventilation path and have a plurality of through holes through which the gas to be processed flowing in the ventilation path passes, and a plurality of adjacent porous bodies among the plurality of porous bodies. The porous body is a group of porous bodies, and for each of the porous body groups, the first and second electrodes disposed outside the porous body located at both ends thereof, the first electrode and the first electrode of each porous body group A high voltage applying means for individually applying a high voltage between the two electrodes to generate plasma in the through-holes of the porous body of each porous body group and the space between the porous bodies; and the first electrode of each porous body group An abnormal discharge detecting means for individually detecting that an abnormal discharge has occurred between the first electrode and the second electrode, and when the abnormal discharge is detected by the abnormal discharge detecting means, the occurrence of the abnormal discharge is detected. The porous body group was defined as an abnormal discharge generation porous body group, and the abnormal discharge generation porous body group Between the first electrode and the second electrode of the abnormal discharge generating porous body group from the high voltage applying means so as to reduce the amount of plasma generated in the space between the through hole and the porous body of the porous body. And a control means for controlling the application of a high voltage.

  For example, in the present invention, when a plurality of porous bodies are divided into a first porous body group and a second porous body group, the first electrode is disposed outside the porous bodies located at both ends of the first porous body group. And the second electrode, the first electrode and the second electrode are arranged outside the porous body located at both ends of the second porous body group, and the first electrode of the first porous body group, A high voltage is individually applied between the second electrode and between the first electrode and the second electrode of the second porous body group, and the first porous body group and the second porous body group Plasma is generated in the through holes of the porous body and the space between the porous bodies. When an abnormal discharge occurs between the first electrode and the second electrode of the first porous body group during the application of the high voltage, the control means causes the first porous body group to be abnormally discharged. And the first electrode and the second electrode of the first porous body group so as to reduce the amount of plasma generated in the through-holes of the porous body of the first porous body group and the space between the porous bodies. The application of a high voltage to and from is controlled. When an abnormal discharge occurs between the first electrode and the second electrode of the second porous body group, the control means sets the second porous body group as an abnormal discharge generating porous body group, and this second porosity The high voltage between the first electrode and the second electrode of the second porous body group so as to reduce the amount of plasma generated in the through holes of the porous body of the body group and the space between the porous bodies Is controlled.

  Further, the present invention provides a plurality of porous bodies that are arranged at intervals in the ventilation path and have a plurality of through holes through which the gas to be processed flowing in the ventilation path passes, and a plurality of adjacent porous bodies among the plurality of porous bodies. The porous body is a group of porous bodies, and for each of the porous body groups, the first and second electrodes disposed outside the porous body located at both ends thereof, the first electrode and the first electrode of each porous body group A high voltage applying means for individually applying a high voltage between the two electrodes to generate plasma in the through holes of the porous bodies of each porous body group and the space between the porous bodies; The porous body group located on the most upstream side in the gas passage direction is set as the upstream porous body group, and it is detected that an abnormal discharge has occurred between the first electrode and the second electrode of the upstream porous body group. Abnormal discharge detection means that detects the occurrence of abnormal discharge by the abnormal discharge detection means The first electrode and the second electrode of the upstream porous body group from the high voltage applying means are reduced so as to reduce the amount of plasma generated in the through holes of the porous body of the upstream porous body group and the space between the porous bodies. And a control means for controlling application of a high voltage to the other electrode.

  For example, in the present invention, the plurality of porous bodies are divided into a first porous body group and a second porous body group, the first porous body group is an upstream porous body group, and the second porous body group is a downstream side. In the case of the porous body group, the first electrode and the second electrode are arranged outside the porous body located at both ends of the upstream porous body group, and outside the porous body located at both ends of the downstream porous body group. A first electrode and a second electrode are arranged, and between the first electrode and the second electrode of the upstream porous body group and between the first electrode and the second electrode of the downstream porous body group A high voltage is separately applied to each other, and plasma is generated in the through-holes of the porous bodies of the upstream porous body group and the second downstream porous body group and the spaces between the porous bodies. When an abnormal discharge is generated between the first electrode and the second electrode of the upstream porous body group during the application of the high voltage, the control means performs the through-hole and the porous body of the porous body of the upstream porous body group. The application of a high voltage between the first electrode and the second electrode of the upstream porous body group is controlled so as to reduce the amount of plasma generated in the space between them.

  In the present invention, the control means controls application of a high voltage between the first electrode and the second electrode so as to reduce the amount of plasma generated when the occurrence of abnormal discharge is detected. As a control method in this case, in the present invention, for example, a positive voltage (+ V) rising from the ground potential in the positive direction is applied to the first electrode, and a negative voltage (−V) falling in the negative direction from the ground potential to the second electrode. ) Are alternately switched so that the state where the positive voltage to the first electrode falls to the ground potential and the state where the negative voltage to the second electrode rises to the ground potential partially overlap. As a result, during the period in which the state in which the positive voltage to the first electrode falls to the ground potential and the state in which the negative voltage to the second electrode rises to the ground potential overlap, the first electrode and the second electrode The voltage is not applied between the two, and this period is set as a high voltage pause period, and the amount of plasma generated is reduced.

  According to the present invention, the abnormal discharge detecting means for detecting that an abnormal discharge has occurred between the first electrode and the second electrode of the porous body or the porous body group is provided, and the abnormal discharge is detected by the abnormal discharge detecting means. The occurrence of abnormal discharge is large because the application of high voltage is controlled so as to reduce the amount of plasma generated in the through-holes of the porous body and the space between the porous bodies. As a result, it becomes possible to continue the processing of the gas to be processed while suppressing the occurrence of abnormal discharge by increasing the high voltage pause period, so that no untreated gas remains.

It is a figure which shows the principal part of one Embodiment (Embodiment 1) of the gas processing apparatus which concerns on this invention. It is a block diagram which shows the structure of the principal part of the abnormal discharge detection part in this gas processing apparatus. It is a time chart which shows the change of the ON timing of drive pulse PS1, PS2 and the drive pulse PS2 which the control part in this gas processing apparatus outputs. 4 is a time chart showing a change in applied voltage to the electrodes of the honeycomb structure when the on-timing time TC of the driving pulse PS2 with respect to the on-timing of the driving pulse PS1 is zero. FIG. 5 is a diagram for explaining application of a high voltage between electrodes of a honeycomb structure when drive pulses PS1 and PS2 are at “H” level in the time chart of FIG. FIG. 5 is a diagram illustrating application of a high voltage between electrodes of a honeycomb structure when drive pulses PS1 and PS2 are at “L” level in the time chart of FIG. 10 is a time chart showing a change in applied voltage to the electrodes of the honeycomb structure when the on-timing time TC of the driving pulse PS2 with respect to the on-timing of the driving pulse PS1 is TC> 0. It is a figure which shows the principal part of other embodiment (Embodiment 2) of the gas processing apparatus which concerns on this invention. It is a figure which shows the principal part of other embodiment (Embodiment 3) of the gas processing apparatus which concerns on this invention. It is a figure which shows the principal part of other embodiment (Embodiment 4) of the gas processing apparatus which concerns on this invention. It is a figure which shows the principal part of other embodiment (Embodiment 5) of the gas processing apparatus which concerns on this invention. It is a figure which shows the principal part of other embodiment (Embodiment 6) of the gas processing apparatus which concerns on this invention. It is a time chart which shows the example which adjusted the advance time TD of the off timing of drive pulse PS1 with respect to the off timing of drive pulse PS2. It is a figure which illustrates the principal part of the conventional gas processing apparatus using discharge plasma.

Hereinafter, the present invention will be described in detail with reference to the drawings.
[Embodiment 1]
FIG. 1 is a diagram showing a main part of an embodiment (Embodiment 1) of a gas processing apparatus according to the present invention. In this figure, the same reference numerals as those in FIG. 14 denote the same or equivalent components as those described with reference to FIG.

  In the first embodiment, the honeycomb structure 4 is arranged in the duct 1, the first electrode 8 and the second electrode 9 are arranged on one and the other side of the honeycomb structure 4, and the first electrode 8 is connected to the positive voltage supply terminal T1 of the high voltage application unit 20 by the conducting wire 16, and the second electrode 9 is connected to the negative voltage supply terminal T2 of the high voltage application unit 20 by the conducting wire 17.

  The honeycomb structure 4 is formed of an insulator such as ceramics, and has a large number of through holes (cells) 4a through which the processing target gas GS passes. The first electrode 8 and the second electrode 9 are made of metal mesh so that the processing target gas GS passes therethrough.

  The high voltage application unit 20 includes transformers TR1, TR2, diodes D1, D2, D3, D4, capacitors C1, C2, transistors Q1, Q2, Q3, resistors R1, R2, R3, and a switching integrated circuit IC1. , IC2 and a control unit CNT. In the high voltage application unit 20, the collector of the transistor Q1 is connected to one end of the primary winding of the transformer TR2, and the emitter of the transistor Q1 is grounded. A power supply voltage Vc is applied to the other end of the primary winding of the transformer TR2.

  In the high voltage application unit 20, the collector of the transistor Q2 is connected to a high potential power supply via a resistor R1, and the emitter of the transistor Q2 is grounded. The collector of the transistor Q3 is connected to one end of the primary winding of the transformer TR1, and the emitter of the transistor Q3 is grounded. A power supply voltage Vc is applied to the other end of the primary winding of the transformer TR1. The base of the transistor Q3 is connected to a connection point between the collector of the transistor Q2 and the resistor R1 via the switching integrated circuit IC1, and the connection line between the switching integrated circuit IC1 and the base of the transistor Q3 has a high potential via the resistor R3. The power supply is connected. The base of the transistor Q1 is connected to the output terminal O2 of the drive pulse PS2 of the control unit CNT via the switching integrated circuit IC2, and the connection line between the switching integrated circuit IC2 and the base of the transistor Q1 is connected via the resistor R2. High-potential power supply is connected. The base of the transistor Q2 is connected to the output terminal O1 of the drive pulse PS1 of the control unit CNT.

  In the high voltage application unit 20, a diode D1 is connected between one end of the secondary winding of the transformer TR1 and the positive voltage supply terminal T1, with the cathode as the positive voltage supply terminal T1 side. A capacitor C1 is connected between the cathode and the other end of the secondary winding of the transformer TR1. A connection line between the capacitor C1 and the other end of the secondary winding of the transformer TR1 is grounded. Further, a diode D3 for preventing a voltage drop when the transformer TR1 is not operating is connected in parallel with the capacitor C1 with its cathode facing the cathode side of the diode D1 and its anode facing the ground side.

  In the high voltage application unit 20, a diode D2 is connected between one end of the secondary winding of the transformer TR2 and the negative voltage supply terminal T2, with the anode serving as the negative voltage supply terminal T2 side. A capacitor C2 is connected between the anode and the other end of the secondary winding of the transformer TR2. A connection line between the capacitor C2 and the other end of the secondary winding of the transformer TR2 is grounded. Further, a diode D4 for preventing a voltage drop when the transformer TR2 is not operating is connected in parallel with the capacitor C2 with its anode facing the anode side of the diode D2 and its cathode facing the ground side.

  In this gas processing apparatus, the control unit CNT is realized by hardware including a processor and a storage device, and a program that realizes various functions in cooperation with these hardware, and is driven as a function unique to the present embodiment. It has a function of outputting pulses PS1 and PS2. In this example, a drive pulse PS1 having a time width TW1 is given from the output terminal O1 to the base of the transistor Q2 at a predetermined period. Further, the drive pulse PS2 having the time width TW2 is given to the switching integrated circuit IC2 at a predetermined cycle from the output terminal O2 of the control unit CNT.

  Further, in this gas treatment device, the high voltage application unit 20 is provided between the positive voltage supply terminal T1 and the negative voltage supply terminal T2, that is, the first electrode 8 and the second electrode of the honeycomb structure 4. 9 is provided with an abnormal discharge detector 21 for detecting that an abnormal discharge has occurred, and a detection signal S1 indicating the amount of abnormal discharge generated from the abnormal discharge detector 21 is controlled by the high voltage application detector 20. It is supposed to be sent to the part CNT.

  FIG. 2 shows a configuration of a main part of the abnormal discharge detection unit 21. The abnormal discharge detection unit 21 includes a DC cut circuit 21A, a discharge frequency detection circuit 21B, a rectifying / smoothing circuit 21C, and a level determination circuit 21D. The DC cut circuit 21 </ b> A has a high voltage generated between the positive voltage supply terminal T <b> 1 and the negative voltage supply terminal T <b> 2 of the high voltage application unit 20, i.e., the first electrode 8 and the second electrode 9 of the honeycomb structure 4. A high voltage applied between them is taken in, and a direct current component included in the high voltage is cut and output. The discharge frequency detection circuit 21B is a noise voltage generated by the discharge between the first electrode 8 and the second electrode 9 with a voltage having a predetermined frequency or higher than the voltage obtained by cutting the DC component output from the DC cut circuit 21A. Take out as. The rectifying / smoothing circuit 21C rectifies and smoothes the noise voltage extracted from the discharge frequency detecting circuit 21B. The level determination circuit 21D determines the magnitude of the noise voltage rectified and smoothed by the rectifying and smoothing circuit 21C, and outputs the determination result as a detection signal S1 indicating the amount of occurrence of abnormal discharge.

  The control unit CNT has a function of receiving the detection signal S1 indicating the amount of abnormal discharge generated from the abnormal discharge detection unit 21 and automatically adjusting the time width of the drive pulse PS2 output from the output terminal O2 of the control unit CNT. ing. In this embodiment, as shown in FIG. 3 (a), the drive pulse PS1 is a pulse having a duty ratio of 50% in which the ON period Ton and the OFF period Toff are equal, and shown in FIGS. 2 (b) and 2 (c). As described above, the advance amount of the ON timing of the drive pulse PS2 with respect to the ON timing of the drive pulse PS1 is automatically adjusted as the advance time TC. In this embodiment, the switching integrated circuits IC1 and IC2 use “494” type switching control ICs.

[Operation when advance time TC of ON timing of drive pulse PS2 is 0]
FIG. 4 shows changes in the applied voltage to the electrodes 8 and 9 of the honeycomb structure 4 when the on-timing advance time TC of the drive pulse PS2 is zero.

  In the high voltage application unit 20, when the drive pulse PS1 from the output terminal O1 of the control unit CNT becomes the “H” level (FIG. 4A: t1 point), the transistor Q2 is turned on. When the transistor Q2 is turned on, the dead time control terminal dc1 of the switching integrated circuit IC1 becomes “L” level, and a high frequency switching pulse is output from the switching integrated circuit IC1. The high-frequency switching pulse turns on / off the transistor Q3, a current flows through the primary winding of the transformer TR1, and a voltage V1 is generated on the secondary winding side of the transformer TR1 (see FIG. 5). This voltage V1 is smoothed by the capacitor C1 and applied to the first electrode 8 of the honeycomb structure 4 via the diode D1. That is, the positive voltage + V1 rising in the positive direction from the ground potential (GND) is applied to the first electrode 8 of the honeycomb structure 4 (FIG. 4B: point t1).

  When the drive pulse PS2 from the output terminal O2 of the control unit CNT becomes the “H” level at the same timing as the drive pulse PS1 (FIG. 4 (c): point t1), the dead time control terminal dc2 of the switching integrated circuit IC2 Becomes “H” level, and the output of the high-frequency switching pulse from the switching integrated circuit IC2 is interrupted. Thereby, the transistor Q1 is turned off, and the current flowing through the secondary winding of the transformer TR2 is cut off. As a result, the accumulated charge in the capacitor C2 is discharged through the path of the secondary winding of the diode D2 and the transformer TR2, and a negative voltage −V2 (described later) applied to the second electrode 9 of the honeycomb structure 4 until then is generated. It changes toward the ground potential (GND) (FIG. 4 (d): t1 point).

  Here, when the drive pulse PS1 rises to the “H” level, that is, when the voltage for applying the positive voltage + V1 to the first electrode 8 is switched, the voltage applied to the second electrode 9 becomes the ground potential (GND). Until it is returned, the difference voltage V1 + V2 between the positive voltage + V1 and the negative voltage −V2 is instantaneously applied between the first electrode 8 and the second electrode 9, and then the voltage drops to V1. A shoot voltage is applied. In this case, when V1 = V2 = V, the double voltage 2V is instantaneously applied between the first electrode 8 and the second electrode 9.

  When the drive pulse PS2 becomes “L” level in the high voltage application unit 20 (FIG. 4C: t2 point), the dead time control terminal dc2 of the switching integrated circuit IC2 becomes “L” level, and the switching integrated circuit A high frequency switching pulse is output from IC2. The transistor Q1 is turned on and off by the output of the high-frequency switching pulse, a current flows through the primary winding of the transformer TR2, and a voltage V2 is generated on the secondary winding side of the transformer TR2 (see FIG. 6). This voltage V2 is smoothed by the capacitor C2 and applied to the second electrode 9 of the honeycomb structure 4 via the diode D2. That is, a negative voltage −V2 that falls in the negative direction from the ground potential (GND) is applied to the second electrode 9 of the honeycomb structure 4 (FIG. 4D: point t2).

  Further, when the drive pulse PS1 from the output terminal O1 of the control unit CNT becomes the “L” level at the same timing as the drive pulse PS2 (FIG. 4A: point t2), the transistor Q2 is turned off. When the transistor Q2 is turned off, the dead time control terminal dc1 of the switching integrated circuit IC1 becomes “H” level, and the output of the high-frequency switching pulse from the switching integrated circuit IC1 is interrupted. Thereby, the transistor Q3 is turned off, and the current flowing through the secondary winding of the transformer TR1 is cut off. As a result, the accumulated charge of the capacitor C1 is discharged through the secondary winding of the transformer TR1 and the path of the diode D1, and the positive voltage + V1 that has been applied to the first electrode 8 of the honeycomb structure 4 until then is the ground potential (GND). ) (FIG. 4B: point t2).

  Here, when the drive pulse PS2 falls to the “L” level, that is, when the voltage for applying the negative voltage −V2 to the second electrode 9 is switched, the applied voltage to the first electrode 8 is the ground potential (GND). ), The difference voltage V1 + V2 between the positive voltage + V1 and the negative voltage −V2 is momentarily applied between the first electrode 8 and the second electrode 9, and then drops to V2. An overshoot voltage is applied. In this case, when V1 = V2 = V, the double voltage 2V is instantaneously applied between the first electrode 8 and the second electrode 9.

  In this way, when the advance time TC of the ON timing of the drive pulse PS2 is 0, between the first electrode 8 and the second electrode 9 at the ON timing and OFF timing of the drive pulses PS1 and PS2. The difference voltage V1 + V2 between the positive voltage + V1 and the negative voltage −V2 is instantaneously applied, the voltage V1 is applied during the on period Ton of the drive pulses PS1 and PS2, and the voltage V2 is applied during the off period Toff of the drive pulses PS1 and PS2. By setting the positive voltage + V1 and the negative voltage −V2 to a high voltage of, for example, several kV to several tens kV, plasma is generated in the through holes 4a of the honeycomb structure 4, and ions and radicals generated in the plasma The harmful gas contained in the processing target gas GS is decomposed into harmless substances.

[Operation when the advance time TC of the ON timing of the drive pulse PS2 is TC> 0]
If the moisture in the gas GS to be processed increases, plasma may be generated excessively and abnormal discharge may occur. In this case, the abnormal discharge detection unit 21 detects the abnormal discharge, and the detection signal S1 indicating the amount of abnormal discharge generated in the control unit CNT increases.

  When the detection signal S1 indicating the amount of occurrence of abnormal discharge from the abnormal discharge detection unit 21 increases, the control unit CNT sets the on-timing advance time TC of the drive pulse PS2 to TC> 0. The advance time TC of the ON timing of the drive pulse PS2 becomes longer as the amount of abnormal discharge generated is larger.

  FIG. 7 shows a change in applied voltage to the electrodes 8 and 9 of the honeycomb structure 4 when the on-time advance time TC of the drive pulse PS2 is TC> 0.

  In the high voltage application unit 20, when the drive pulse PS2 from the output terminal O2 of the control unit CNT becomes “H” level (FIG. 7 (c): point t0), the dead time control terminal dc2 of the switching integrated circuit IC2 is “ The high-frequency switching pulse output from the switching integrated circuit IC2 is interrupted. Thereby, the transistor Q1 is turned off, and the current flowing through the secondary winding of the transformer TR2 is cut off. As a result, the accumulated charge in the capacitor C2 is discharged through the path of the secondary winding of the diode D2 and the transformer TR2, and a negative voltage −V2 (described later) applied to the second electrode 9 of the honeycomb structure 4 until then is generated. It changes toward the ground potential (GND) (FIG. 7 (d): t0 point).

  When the drive pulse PS1 from the output terminal O1 of the control unit CNT becomes “H” level after the TC time has elapsed (FIG. 7A: point t1), the transistor Q2 is turned on. When the transistor Q2 is turned on, the dead time control terminal dc1 of the switching integrated circuit IC1 becomes “L” level, and a high frequency switching pulse is output from the switching integrated circuit IC1. The high-frequency switching pulse turns on / off the transistor Q3, a current flows through the primary winding of the transformer TR1, and a voltage V1 is generated on the secondary winding side of the transformer TR1 (see FIG. 5). This voltage V1 is smoothed by the capacitor C1 and applied to the first electrode 8 of the honeycomb structure 4 via the diode D1. That is, the positive voltage + V1 rising in the positive direction from the ground potential (GND) is applied to the first electrode 8 of the honeycomb structure 4 (FIG. 7B: point t1).

  Here, when the drive pulse PS2 rises to the “H” level, that is, when the voltage is switched to switch the application of the negative voltage −V2 to the second electrode 9 to the application of the positive voltage + V1 to the first electrode 8. Until the drive pulse PS1 rises to the “H” level (approximately TC time), the positive voltage + V1 to the first electrode 8 falls to the ground potential and the negative voltage −V2 to the second electrode 9 Is overlapped with the ground potential and no voltage is applied between the first electrode 8 and the second electrode 9. That is, the high voltage between the first electrode 8 and the second electrode 9 is approximately TC time from when the drive pulse PS2 rises to the “H” level until the drive pulse PS1 rises to the “H” level. Application of (V1, V2) is suspended.

  When the drive pulse PS2 becomes “L” level in the high voltage application unit 20 (FIG. 7C: point t2), the dead time control terminal dc2 of the switching integrated circuit IC2 becomes “L” level, and the switching integrated circuit A high frequency switching pulse is output from IC2. The transistor Q1 is turned on and off by the output of the high-frequency switching pulse, a current flows through the primary winding of the transformer TR2, and a voltage V2 is generated on the secondary winding side of the transformer TR2 (see FIG. 6). This voltage V2 is smoothed by the capacitor C2 and applied to the second electrode 9 of the honeycomb structure 4 via the diode D2. That is, the negative voltage −V2 that falls in the negative direction from the ground potential (GND) is applied to the second electrode 9 of the honeycomb structure 4 (FIG. 7D: point t2).

  Further, when the drive pulse PS1 from the output terminal O1 of the control unit CNT becomes the “L” level at the same timing as the drive pulse PS2 (FIG. 7A: t2 point), the transistor Q2 is turned off. When the transistor Q2 is turned off, the dead time control terminal dc1 of the switching integrated circuit IC1 becomes “H” level, and the output of the high-frequency switching pulse from the switching integrated circuit IC1 is interrupted. Thereby, the transistor Q3 is turned off, and the current flowing through the secondary winding of the transformer TR1 is cut off. As a result, the accumulated charge of the capacitor C1 is discharged through the secondary winding of the transformer TR1 and the path of the diode D1, and the positive voltage + V1 that has been applied to the first electrode 8 of the honeycomb structure 4 until then is the ground potential (GND). ) (FIG. 7B: point t2).

  Here, when the drive pulse PS2 falls to the “L” level, that is, when the voltage for applying the negative voltage −V2 to the second electrode 9 is switched, the applied voltage to the first electrode 8 is the ground potential (GND). ), The difference voltage V1 + V2 between the positive voltage + V1 and the negative voltage −V2 is momentarily applied between the first electrode 8 and the second electrode 9, and then drops to V2. An overshoot voltage is applied. In this case, when V1 = V2 = V, the double voltage 2V is instantaneously applied between the first electrode 8 and the second electrode 9.

  Thus, when the advance time TC of the ON timing of the drive pulse PS2 is TC> 0, the application of the negative voltage −V2 to the second electrode 9 is applied to the positive voltage + V1 to the first electrode 8. When switching the voltage to be applied, the positive voltage + V1 to the first electrode 8 falls to the ground potential and the negative voltage −V2 to the second electrode 9 rises to the ground potential for approximately TC time. The amount of plasma generated in the through-holes 4a of the honeycomb structure 4 with the state overlapped and no voltage is applied between the first electrode 8 and the second electrode 9, and this period is defined as a high voltage pause period. Decrease.

  Due to the decrease in the amount of generated plasma, abnormal discharge is suppressed and the processing of the processing target gas is continued. Further, the gas to be treated GS is adsorbed on the honeycomb structure 4 during the high voltage pause period, and the decomposition process is performed when the high voltage is applied including the amount adsorbed during the pause period. Even in a state where the amount of gas is reduced, gas treatment is efficiently performed.

[Embodiment 2]
In the first embodiment, only one honeycomb structure 4 is arranged in the duct 1, but a plurality of honeycomb structures 4 may be arranged in the duct 1.

  FIG. 8 shows an example (Embodiment 2) in which a plurality of honeycomb structures 4 are arranged in the duct 1. In the second embodiment, the honeycomb structure 4 (4-1 to 4-3) is arranged in the duct 1 by providing a predetermined gap G (G1, G2) along the direction from the inlet to the outlet of the duct 1. The first electrode (upstream electrode) 8 is disposed on the upstream side of the honeycomb structure 4-1 disposed on the most upstream side of the honeycomb structure 4, and the honeycomb structure 4-3 disposed on the most downstream side. A second electrode (downstream electrode) 9 is disposed on the downstream side, the upstream electrode 8 is connected to the positive voltage supply terminal T1 of the high voltage application unit 20 by a conducting wire 16, and the downstream electrode 9 is connected to a high voltage by a conducting wire 17. The negative voltage supply terminal T2 of the application unit 20 is connected. The high voltage application unit 20 is the same as that used in the first embodiment.

  Moreover, with respect to the high voltage application part 20, between the positive voltage supply terminal T1 and the negative voltage supply terminal T2, that is, the upstream electrode 8 and the downstream electrode of the honeycomb structure 4 (4-1 to 4-3). 9 is provided with an abnormal discharge detection unit 21 that detects that an abnormal discharge has occurred, and a control signal of the high voltage application detection unit 20 is sent to the detection signal S1 indicating the amount of abnormal discharge generated from the abnormal discharge detection unit 21. It is supposed to be sent to CNT.

  In the second embodiment, the number of through holes 4a per unit area of each honeycomb structure 4 is made equal. That is, the same type of honeycomb structure 4 having the same number of through holes 4a per unit area is used as the honeycomb structures 4-1 to 4-3. Further, the gap G1 between the honeycomb structures 4-1 and 4-2 and the gap G2 between the honeycomb structures 4-2 and 4-3 are equal, for example, 0.5 mm to several mm. Yes. Thereby, an air layer 12-1 is formed between the honeycomb structures 4-1 and 4-2, and an air layer 12-2 is formed between the honeycomb structures 4-2 and 4-3. . Hereinafter, the air layer 12 (12-1, 12-2) is referred to as a space gap.

  Also in this gas processing apparatus, the drive pulse PS1 is applied to the base of the transistor Q2, and the drive pulse PS2 is applied to the switching integrated circuit IC2 of the high voltage application unit 20. Thus, in the same manner as in the first embodiment, the positive voltage + V1 and the negative voltage -V2 are alternately provided between the upstream electrode (first electrode) 8 and the downstream electrode (second electrode) 9. Applied. By the application of the high voltages V1 and V2, plasma is generated in the through holes 4a of the honeycomb structure 4 and the space gap 12 between the honeycomb structures 4, and the processing target gas GS is generated by ions and radicals generated in the plasma. Hazardous gas contained in is decomposed into harmless substances. In addition, during the application of the high voltages V1 and V2, the high voltage pause period is automatically adjusted by the detection signal S1 indicating the amount of abnormal discharge generated from the abnormal discharge detection unit 21 while suppressing the occurrence of abnormal discharge. The processing of the processing target gas GS is continued.

  In this gas processing apparatus, plasma is generated not only in the through holes 4 a of the honeycomb structure 4 but also in the space gap 12 between the honeycomb structures 4. For this reason, in addition to the molecular decomposition effect of the harmful gas in the through hole 4a, the molecular decomposition effect of the harmful gas in the space gap 12 between the honeycomb structures 4 is added, and the molecular decomposition effect in the through hole 4a is further increased. The synergistic effect with the molecular decomposition effect in the space gap 12 between the honeycomb structures 4 promotes the decomposition of harmful gases into harmless substances and increases the gas processing capacity.

  Further, in this gas processing apparatus, in the space gap 12 between the honeycomb structures 4, an electric field spreads from the edge surface of the opposing through hole 4 a, and a large amount of uniform plasma is generated. Thereby, the influence by the dispersion | variation in the plasma which generate | occur | produces in the through-hole 4a becomes small, and gas processing capability is stabilized.

  Further, in this gas treatment device, since the space gap 12 that is an air layer is provided between the honeycomb structures 4, the space gap 12 stabilizes the impedance between the upstream electrode 8 and the downstream electrode 9, The change in the flowing current is small with respect to the impedance change due to moisture absorption and drying of the honeycomb structure. As a result, the change in the high voltage value applied between the upstream electrode 8 and the downstream electrode 9 is reduced, and there is no need to use a special high voltage power supply designed exclusively.

  Further, in this gas processing apparatus, the electrodes need only be the two electrodes of the upstream electrode 8 and the downstream electrode 9, and it is not necessary to arrange the electrodes for each honeycomb structure 4. As a result, the number of parts is reduced, the structure is simplified, the number of assembly steps is reduced, and the cost can be reduced.

[Embodiment 3]
In the second embodiment, the plurality of honeycomb structures 4 are provided in the duct 1 along the direction from the inlet to the outlet of the duct 1. However, as shown in FIG. A plurality of honeycomb structures 4 may be provided in the duct 1 along a direction orthogonal to the direction.

  In this case, the honeycomb structures 4 are arranged at intervals along the direction orthogonal to the direction from the inlet to the outlet of the duct 1, so that the honeycomb structures 4 are arranged along the direction from the inlet to the outlet of the duct 1. Compared to the case, the time during which the processing target gas GS is exposed to the plasma in the through holes 4a of the honeycomb structures 4 and the space gaps 12 between the honeycomb structures 4 becomes longer. As a result, the opportunity for gas decomposition is increased, the gas processing capacity is improved, and it is possible to prevent the gas processing capacity from being lowered in a high-speed flow.

[Embodiment 4]
FIG. 10 shows a main part of another embodiment (Embodiment 4) of the gas treatment apparatus according to the present invention. In the fourth embodiment, a gap G1 is provided between the honeycomb structures 4-1 and 4-2, and a gap G2 is provided between the honeycomb structures 4-3 and 4-4. 4-1 to 4-4 are arranged in the duct 1.

  In addition, adjacent honeycomb structures 4-1 and 4-2 among the plurality of honeycomb structures 4 in the duct 1 serve as a first honeycomb structure group 4A and are positioned at both ends of the first honeycomb structure group 4A. Outside the honeycomb structures 4-1 and 4-2, the electrode 8A is disposed as the first electrode, and the electrode 9A is disposed as the second electrode.

  Similarly, the adjacent honeycomb structures 4-3 and 4-4 among the plurality of honeycomb structures 4 in the duct 1 are defined as the second honeycomb structure group 4B, and both ends of the second honeycomb structure group 4B. Outside the honeycomb structures 4-3 and 4-3, the electrode 8B is disposed as the first electrode, and the electrode 9B is disposed as the second electrode.

  The electrodes 8A, 8B and 9A, 9B are made of metal mesh so that the gas to be processed GS passes through. In the fourth embodiment, the electrodes 8A and 9A are connected to the positive voltage supply terminal T1 and the negative voltage supply terminal T2 of the first high voltage applying unit 20A by the conductive wires 16A and 17A, and the electrodes 8B and 9B are connected to the conductive wire 16B. And 17B are connected to the positive voltage supply terminal T1 and the negative voltage supply terminal T2 of the second high voltage application unit 20B. The high voltage application units 20A and 20B are the same as the high voltage application unit 20 used in the first embodiment.

  Further, with respect to the high voltage application unit 20A, the first electrode 8A and the first electrode 8A between the positive voltage supply terminal T1 and the negative voltage supply terminal T2, that is, the honeycomb structure group 4A (4-1, 4-2). An abnormal discharge detector 21A that detects the occurrence of abnormal discharge between the two electrodes 9A is provided, and a detection signal S1A indicating the amount of abnormal discharge generated from the abnormal discharge detector 21A is provided as a high voltage application detector 20A. To the control unit CNTA.

  Further, the first electrode 8B and the first electrode 8B of the honeycomb structure group 4B (4-3, 4-4) are connected to the high voltage application unit 20B between the positive voltage supply terminal T1 and the negative voltage supply terminal T2. An abnormal discharge detection unit 21B that detects the occurrence of abnormal discharge between the two electrodes 9B is provided, and a detection signal S1B indicating the amount of abnormal discharge generated from the abnormal discharge detection unit 21B is provided as a high voltage application detection unit 20B. To the control unit CNTB.

  Also in this gas processing apparatus, in the same manner as in the first embodiment, the first honeycomb structure group 4A is provided between the first electrode 8A and the second electrode 9A and the second honeycomb structure group 4B. A positive voltage + V1 and a negative voltage -V2 are alternately applied between the first electrode 8B and the second electrode 9B. By the application of the high voltages V1 and V2, plasma is generated in the through holes 4a of the honeycomb structure 4 and the space gap 12 between the honeycomb structures 4, and the processing target gas GS is generated by ions and radicals generated in the plasma. Hazardous gas contained in is decomposed into harmless substances.

  Further, during the application of the high voltages V1 and V2, the first electrode 8A and the second electrode of the first honeycomb structure group 4A are detected by the detection signal S1A indicating the amount of abnormal discharge generated from the abnormal discharge detector 21A. 9A is automatically adjusted, and the detection signal S1B indicating the amount of abnormal discharge generated from the abnormal discharge detector 21B is used to detect the first electrode 8B of the second honeycomb structure group 4B. The high voltage pause period with respect to the second electrode 9B is automatically adjusted, and the processing of the processing target gas GS is continued while suppressing the occurrence of abnormal discharge.

  In this gas processing apparatus, the first electrode 10 and the second electrode 9 of the first honeycomb structure group 4A and between the first electrode 8 and the second electrode 9 and of the second honeycomb structure group 4B. Since a high voltage is individually applied between the two, a potential in the space gaps 12-1 and 12-2 can be stably maintained in a high electric field state, and plasma can be stably generated.

  In this gas treatment apparatus, the high voltage (VA) applied to the first honeycomb structure group 4A and the high voltage (VB) applied to the second honeycomb structure group 4B are set to different values. Good. If the values of the high voltage VA and the high voltage VB are made different from each other, the types of harmful gases that can be decomposed by changing the amount of plasma generated in the first honeycomb structure group 4A and the second honeycomb structure group 4B Can be made different.

[Embodiment 5]
FIG. 11 shows a main part of another embodiment (embodiment 5) of the gas treatment apparatus according to the present invention. In the fifth embodiment, a gap G1 is provided between the honeycomb structures 4-1 and 4-2, and a gap G2 is provided between the honeycomb structures 4-3 and 4-4. The honeycomb structures 4-1 to 4-6 are arranged in the duct 1 with a gap G3 provided between 4-5 and 4-6.

  In addition, adjacent honeycomb structures 4-1 and 4-2 among the plurality of honeycomb structures 4 in the duct 1 serve as a first honeycomb structure group 4A and are positioned at both ends of the first honeycomb structure group 4A. Outside the honeycomb structures 4-1 and 4-2, the electrode 8A is disposed as the first electrode, and the electrode 9A is disposed as the second electrode.

  Similarly, the adjacent honeycomb structures 4-3 and 4-4 among the plurality of honeycomb structures 4 in the duct 1 are defined as the second honeycomb structure group 4B, and both ends of the second honeycomb structure group 4B. Outside the honeycomb structures 4-3 and 4-3, the electrode 8B is disposed as the first electrode, and the electrode 9B is disposed as the second electrode.

  Similarly, adjacent honeycomb structures 4-5 and 4-6 among the plurality of honeycomb structures 4 in the duct 1 are defined as a third honeycomb structure group 4C, and both ends of the third honeycomb structure group 4C are arranged. On the outside of the honeycomb structures 4-5 and 4-6 positioned in the area, the electrode 8C is disposed as the first electrode, and the electrode 9C is disposed as the second electrode.

  The electrodes 8A, 8B, 8C and 9A, 9B, 9C are made of metal mesh so that the gas GS to be processed passes therethrough. In the fifth embodiment, the electrodes 8A and 9A are connected to the positive voltage supply terminal T1 and the negative voltage supply terminal T2 of the high voltage applying unit 20A by the conductive wires 16A and 17A, and the electrodes 8B and 9B are connected by the conductive wires 16B and 17B. The positive voltage supply terminal T1 and the negative voltage supply terminal T2 of the high voltage application unit 20B are connected, and the electrodes 8C and 9C are connected to the positive voltage supply terminal T1 and the negative voltage supply terminal T2 of the high voltage application unit 20C by conducting wires 16C and 17C. Like to do. The high voltage application units 20A, 20B, and 20C are the same as the high voltage application unit 20 used in the first embodiment.

  Further, with respect to the high voltage application unit 20A, the first electrode 8A and the first electrode 8A between the positive voltage supply terminal T1 and the negative voltage supply terminal T2, that is, the honeycomb structure group 4A (4-1, 4-2). An abnormal discharge detector 21A that detects the occurrence of abnormal discharge between the two electrodes 9A is provided, and a detection signal S1A indicating the amount of abnormal discharge generated from the abnormal discharge detector 21A is provided as a high voltage application detector 20A. To the control unit CNTA.

  Further, the first electrode 8B and the first electrode 8B of the honeycomb structure group 4B (4-3, 4-4) are connected to the high voltage application unit 20B between the positive voltage supply terminal T1 and the negative voltage supply terminal T2. An abnormal discharge detection unit 21B that detects the occurrence of abnormal discharge between the two electrodes 9B is provided, and a detection signal S1B indicating the amount of abnormal discharge generated from the abnormal discharge detection unit 21B is provided as a high voltage application detection unit 20B. To the control unit CNTB.

  Further, with respect to the high voltage application unit 20C, the first electrode 8C and the first electrode 8C of the honeycomb structure group 4C (4-5, 4-6) are disposed between the positive voltage supply terminal T1 and the negative voltage supply terminal T2. An abnormal discharge detection unit 21C that detects the occurrence of abnormal discharge between the two electrodes 9C is provided, and a detection signal S1C indicating the amount of abnormal discharge generated from the abnormal discharge detection unit 21C is provided as a high voltage application detection unit 20C. To the control unit CNTC.

  Also in this gas processing apparatus, in the same manner as in the first embodiment, the first honeycomb structure group 4A has the first electrode 8A and the second electrode 9A, and the second honeycomb structure group 4B has the second structure. The positive voltage + V1 and the negative voltage −V2 alternate between the first electrode 8B and the second electrode 9B and between the first electrode 8C and the second electrode 9C of the third honeycomb structure group 4C. To be applied. By the application of the high voltages V1 and V2, plasma is generated in the through holes 4a of the honeycomb structure 4 and the space gap 12 between the honeycomb structures 4, and the processing target gas GS is generated by ions and radicals generated in the plasma. Hazardous gas contained in is decomposed into harmless substances.

  Further, during the application of the high voltages V1 and V2, the first electrode 8A and the second electrode of the first honeycomb structure group 4A are detected by the detection signal S1A indicating the amount of abnormal discharge generated from the abnormal discharge detector 21A. 9A is automatically adjusted, and the detection signal S1B indicating the amount of abnormal discharge generated from the abnormal discharge detector 21B is used to detect the first electrode 8B of the second honeycomb structure group 4B. The rest period of the high voltage with respect to the second electrode 9B is automatically adjusted, and the first signal of the second honeycomb structure group 4C is detected by the detection signal S1C indicating the amount of abnormal discharge generated from the abnormal discharge detector 21C. The rest period of the high voltage between the electrode 8C and the second electrode 9C is automatically adjusted, and the processing of the processing target gas GS is continued while suppressing the occurrence of abnormal discharge.

  In this gas processing apparatus, the first electrode 8B and the second electrode 9B of the second honeycomb structure group 4B are provided between the first electrode 8A and the second electrode 9A of the first honeycomb structure group 4A. And a high voltage is individually applied between the first electrode 8C and the second electrode 9C of the third honeycomb structure group 4C, so that the space gaps 12-1, 12-2, 12 -3 can be stably maintained in a high electric field state, and plasma can be stably generated.

  In this gas treatment apparatus, the high voltage (VA) applied to the first honeycomb structure group 4A, the high voltage (VB) applied to the second honeycomb structure group 4B, and the third honeycomb structure The high voltage (VC) applied to the group 4C may be set to a different value. If the values of the high voltage VA, the high voltage VB, and the high voltage VC are made different, the plasma of the first honeycomb structure group 4A, the second honeycomb structure group 4B, and the third honeycomb structure group 4C is changed. It is possible to change the amount of generated harmful gas by changing the generation amount.

[Embodiment 6]
In the fifth embodiment, the occurrence of abnormal discharge in the honeycomb structure groups 4A, 4B, and 4C is individually detected. However, the honeycomb structure group 4A located on the most upstream side in the passage direction of the processing target gas GS. The occurrence of abnormal discharge in the honeycomb structure 4A may be detected, and the high voltage pause period between the first electrode 8A and the second electrode 9A of the honeycomb structure group 4A may be automatically adjusted.

  When the processing target gas GS contains a large amount of moisture, abnormal discharge is more likely to occur in the upstream honeycomb structure group than in the downstream honeycomb structure group. This is because moisture is consumed in the honeycomb structure group on the upstream side, so that the moisture reaching the honeycomb structure group on the downstream side is less than that on the upstream side.

  Therefore, in the sixth embodiment, as shown in FIG. 12, the first electrode of the honeycomb structure group 4A is applied only to the honeycomb structure group 4A located on the most upstream side in the passage direction of the processing target gas GS. An abnormal discharge detector 21A that detects that an abnormal discharge has occurred is provided between 8A and the second electrode 9A, and a detection signal S1 that indicates the amount of abnormal discharge generated by the abnormal discharge detector 21A is a high voltage. By sending it to the control unit CNTA of the application unit 20A, the high voltage pause period between the first electrode 8A and the second electrode 9A of the honeycomb structure group 4A is automatically adjusted. Thereby, the abnormal discharge detection part for the honeycomb structure groups 4B and 4C can be omitted, and the configuration can be simplified.

  In Embodiments 2 to 6 described above, the number of through-holes 4a per unit area of the honeycomb structure 4 (4-1 to 4-6) is made equal. 4-6) The number of through holes 4a per unit area may be selectively varied.

  For example, in the configuration shown in FIG. 10, the number of through holes 4a per unit area is reduced for the honeycomb structures 4-1 and 4-2, and the number per unit area for the honeycomb structures 4-3 and 4-4. The number of through holes 4a may be increased, or the number of through holes 4a per unit area may be increased in the order of honeycomb structures 4-1, 4-2, 4-3, and 4-4. .

  When the number of the through holes 4a per unit area is increased in the order of the honeycomb structure 4-1, 4-2, 4-3, 4-4, the honeycomb structure 4-1, 4-2, 4-3, 4 The amount of generated plasma increases in the order of −4, and the types of harmful gases that can be decomposed in each honeycomb structure 4 can be made different.

  For example, in the case where harmful gases A, B, C, and D having higher energy levels in their molecules are included in the processing target gas GS, the harmful gas A included in the processing target gas GS is converted into the honeycomb structure. 4-1 is decomposed, the harmful gas B contained in the processing target gas GS is decomposed by the honeycomb structure 4-2, and the harmful gas C contained in the processing target gas GS is decomposed by the honeycomb structure 4-3. The kind of harmful gas that can be decomposed in each honeycomb structure 4 can be made different, for example, the harmful gas D contained in the target gas GS is decomposed by the honeycomb structure 4-4.

  In this case, when the harmful gas B is decomposed in the honeycomb structure 4-2, the harmful gas A that could not be decomposed by the honeycomb structure 4-1 is decomposed, and the harmful gas C in the honeycomb structure 4-3 is decomposed. At the time of decomposition, harmful gases A and B that could not be decomposed by the honeycomb structures 4-1 and 4-2 are decomposed, and at the time of decomposition of the harmful gas D by the honeycomb structures 4-4, the honeycomb structure 4 Hazardous gases A, B, and C that could not be decomposed by -1,4-2,4-3 are decomposed.

  With such a method, a by-product (for example, ozone) generated during the decomposition of the harmful gas, compared with the case where all the harmful gases A, B, C, and D are decomposed by one honeycomb structure 4. ) Can be reduced.

  Moreover, in Embodiment 2-6 mentioned above, although the space | interval G (G1, G2, G3) between the honeycomb structures 4 is made equal, you may make it differ. For example, in the configuration shown in FIG. 11, if the gaps G1, G2, G3 between the honeycomb structures 4 are made different, the amount of plasma generated in the space gaps 12-1, 12-2, 12-3 will be different. The same actions and effects as when the number of the through holes 4a per unit area of the honeycomb structures 4-1 to 4-6 are selectively made different can be obtained. In this case, the honeycomb structures 4-1 to 4-6 can be the same type of honeycomb structure having the same number of the through holes 4a per unit area, so that it is not necessary to increase the types of components.

  Moreover, in Embodiments 1 to 6 described above, the honeycomb structure 4 may have a catalytic function for decomposing ozone. For example, in the configuration shown in FIG. 10, the downstream position of the honeycomb structure 4-4. A catalyst for decomposing ozone may be provided.

  Moreover, in Embodiment 2 and 3 (FIG. 8, FIG. 9) mentioned above, as long as the number of the honeycomb structures 4 is two or more, it does not matter how many. In the above-described fourth embodiment (FIG. 10), the number of honeycomb structures 4 is not limited as long as two or more honeycomb structure groups can be formed. In the fifth embodiment (FIG. 11), an example in which three honeycomb structure groups are provided is shown as a modification of the fourth embodiment.

Moreover, in Embodiment 1-6 mentioned above, ozone may be generated in large quantities as a by-product, and you may make it divert as an ozone generator.
Moreover, in Embodiment 1-6 mentioned above, although the through-hole 4a is provided in the honeycomb structure 4 in the shape of a honeycomb, what is necessary is just to provide many through-holes 4a, and is restricted to a honeycomb shape. is not.

  In the first to sixth embodiments described above, the drive pulse PS1 is turned on by the detection signal S1 (S1A, S1B, S1C) indicating the amount of abnormal discharge generated from the abnormal discharge detector 21 (21A, 21B, 21C). Although the on-timing advance time TC of the drive pulse PS2 with respect to the timing is automatically adjusted, as shown in FIG. 13, the off-timing advance time TD of the drive pulse PS1 with respect to the off-timing of the drive pulse PS2 is automatically adjusted. It may be. Further, both the ON timing advance time TC of the drive pulse PS2 with respect to the ON timing of the drive pulse PS1 and the OFF timing advance time TD of the drive pulse PS1 with respect to the OFF timing of the drive pulse PS2 may be automatically adjusted. In addition, when the abnormal discharge detection unit 21 (21A, 21B, 21C) detects the occurrence of abnormal discharge exceeding a predetermined level, and detects the occurrence of abnormal discharge above a predetermined level, the ON timing of the drive pulse PS2 is detected. The advance time TC may be changed from TC = 0 to a predetermined value of TC> 0.

The gas processing apparatus of the present invention can also be applied to so-called reforming for generating a hydrogen-containing gas from hydrocarbons or the like for the purpose of efficiently generating hydrogen used in a fuel cell or the like. For example, in the case of octane (substance relatively close to the average molecular weight of gasoline) C ₈ H ₁₈ , when supplied to this gas treatment device, the chemical reaction represented by the following formula (1) is promoted, and as a result, hydrogen gas is efficiently generated. can do.
C ₈ H ₁₈ + 8H ₂ O + 4 (O ₂ + 4N ₂ ) → 8CO ₂ + 17H ₂ + 16N ₂ ... (1)

  DESCRIPTION OF SYMBOLS 1 ... Duct (ventilation path), 4 (4-1 to 4-6) ... Honeycomb structure, 4a ... Through-hole (cell), 4A, 4B, 4C ... Honeycomb structure group, 8 (8A, 8B, 8C) , 9 (9A, 9B, 9C) ... electrode, 12 (12-1 to 12-3) ... space gap, 16 (16A, 16B, 16C), 17 (17A, 17B, 17C) ... conductor, G (G1 G3) ... interval, GS ... gas to be processed, 20 (20A, 20B, 20C) ... high voltage application unit, 21 (21A, 21B, 21C) ... abnormal discharge detection unit, TR1, TR2 ... transformer, D1, D2, D3 , D4 ... diode, C1, C2 ... capacitor, Q1, Q2, Q3 ... transistor, R1, R2, R3 ... resistor, T1 ... positive voltage supply terminal, T2 ... negative voltage supply terminal, IC1, IC2 ... integrated circuit for switching, CNT (CNTA, NTB, CNTC) ... control unit.

Claims (5)

A porous body that is disposed in the ventilation path and has a large number of through holes through which the gas to be processed flowing in the ventilation path passes;
First and second electrodes disposed on one and the other outside of the porous body;
High voltage applying means for applying a high voltage between the first electrode and the second electrode to generate plasma in the through hole of the porous body;
Abnormal discharge detection means for detecting that an abnormal discharge has occurred between the first electrode and the second electrode;
When the occurrence of abnormal discharge is detected by the abnormal discharge detecting means, the first electrode and the second electrode from the high voltage applying means are reduced so as to reduce the amount of plasma generated in the through hole of the porous body. And a control means for controlling application of a high voltage to the electrode. A plurality of porous bodies that are arranged at intervals in the ventilation path and have a large number of through holes through which the gas to be processed flowing in the ventilation path passes;
An upstream electrode disposed on the upstream side of the porous body disposed upstream of the processing target gas among the plurality of porous bodies; and
A downstream electrode disposed on the downstream side of the porous body disposed on the most downstream side in the passage direction of the processing target gas among the plurality of porous bodies;
One of the upstream electrode and the downstream electrode is a first electrode, the other is a second electrode, and a high voltage is applied between the first electrode and the second electrode, and the through hole of the porous body And high voltage applying means for generating plasma in the space between the porous bodies,
Abnormal discharge detection means for detecting that an abnormal discharge has occurred between the first electrode and the second electrode;
When occurrence of abnormal discharge is detected by the abnormal discharge detection means, the high voltage application means from the high voltage application means reduces the amount of plasma generated in the through hole of the porous body and the space between the porous bodies. A gas processing apparatus comprising: control means for controlling application of a high voltage between the first electrode and the second electrode. A plurality of porous bodies that are arranged at intervals in the ventilation path and have a large number of through holes through which the gas to be processed flowing in the ventilation path passes;
A plurality of adjacent porous bodies among the plurality of porous bodies are used as a group of porous bodies, and for each of the porous bodies, first and second electrodes disposed outside the porous bodies located at both ends thereof,
High voltage application for generating plasma in the through holes of the porous bodies of each porous body group and the space between the porous bodies by individually applying a high voltage between the first electrode and the second electrode of each porous body group Means,
Abnormal discharge detection means for individually detecting that an abnormal discharge has occurred between the first electrode and the second electrode of each porous body group;
When occurrence of abnormal discharge is detected by the abnormal discharge detection means, the porous body group in which occurrence of the abnormal discharge is detected is defined as an abnormal discharge generation porous body group, and the porous body of the abnormal discharge generation porous body group penetrates the porous body. In order to reduce the amount of plasma generated in the space between the pores and the porous body, the high voltage applying means is connected between the first electrode and the second electrode of the abnormal discharge generating porous body group. And a control means for controlling application of a high voltage. A plurality of porous bodies that are arranged at intervals in the ventilation path and have a large number of through holes through which the gas to be processed flowing in the ventilation path passes;
A plurality of adjacent porous bodies among the plurality of porous bodies are used as a group of porous bodies, and for each of the porous bodies, first and second electrodes disposed outside the porous bodies located at both ends thereof,
High voltage application for generating plasma in the through holes of the porous bodies of each porous body group and the space between the porous bodies by individually applying a high voltage between the first electrode and the second electrode of each porous body group Means,
Among the plurality of porous body groups, a porous body group located on the most upstream side in the direction of passage of the gas to be treated is defined as an upstream porous body group, and the first electrode and the second electrode of the upstream porous body group, An abnormal discharge detection means for detecting that an abnormal discharge has occurred between,
When the occurrence of abnormal discharge is detected by the abnormal discharge detection means, the high voltage is applied so as to reduce the amount of plasma generated in the through holes of the porous bodies of the upstream porous body group and the space between the porous bodies. And a control means for controlling application of a high voltage between the first electrode and the second electrode of the upstream porous body group from the application means. In the gas treatment device according to any one of claims 1 to 4,
The control means includes
When the occurrence of abnormal discharge is detected by the abnormal discharge detection means,
A positive voltage rising in the positive direction from the ground potential is applied to the first electrode, a negative voltage falling in the negative direction from the ground potential is applied to the second electrode, and a positive voltage to the first electrode is decreased to the ground potential. The gas processing apparatus is characterized in that it is alternately switched and applied so that the state in which the negative voltage to the second electrode rises to the ground potential partially overlaps.

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