JP5486208B2 - Gas processing equipment - Google Patents

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. 17 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.

  This type of gas processing equipment monitors the environmental elements of the target gas that affect the generation of plasma, such as the wind speed, humidity, and temperature of the target gas, and controls the high voltage to be applied based on the monitoring results of the environmental element. It is known that it is necessary (see, for example, Patent Document 3).

  For example, when the passing air volume of the gas to be processed is small, the gas processing capacity can be reduced to save energy. For this reason, the wind speed of the gas to be processed is detected, and if the wind speed (air volume) of the gas to be processed is high, the plasma generation capacity is increased. If the wind speed (air volume) of the gas to be processed is small, the plasma generation capacity is increased. The high voltage applied to the honeycomb structure is controlled so as to decrease.

  In addition, when the honeycomb structure has a large amount of moisture in the gas to be treated (high humidity state), plasma is actively generated, and conversely, when the moisture is low (low humidity state), the generation of plasma is suppressed. For this reason, the humidity of the gas to be treated is detected, and in the high humidity state, the voltage applied to the honeycomb structure is reduced to save energy, and in the low humidity state, the voltage applied to the honeycomb structure is increased to increase the gas processing capacity.

  In the honeycomb structure, when the temperature of the gas to be treated is high (high temperature state), plasma is actively generated, and conversely, when the temperature is low (low temperature state), generation of plasma is suppressed. For this reason, the temperature of the gas to be treated is detected, and the applied voltage to the honeycomb structure is lowered in a high temperature state to save energy, and the applied voltage to the honeycomb structure is raised in a low temperature state to increase the gas processing capacity.

JP 2000-140562 A JP 2001-276561 A JP 2004-68613 A

  However, in the conventional gas processing apparatus described above, when a plurality of types of environmental elements of the gas to be processed that affect the generation of plasma are taken into account, a request to increase or decrease the plasma generation capability between the plurality of types of environmental elements is required. The algorithm in case of conflict was not established, and the gas treatment capacity could not be adjusted appropriately for changes in multiple types of environmental factors.

  The present invention has been made to solve the above-described problems, and the object of the present invention is to provide a gas processing capability with respect to changes in a plurality of types of environmental elements of the gas to be processed that affect the generation of plasma. An object of the present invention is to provide a gas processing apparatus capable of appropriately adjusting the pressure.

In order to achieve such an object, the present invention provides a plurality of porous bodies that are arranged in a ventilation path and have a large number of through-holes through which a gas to be processed flowing in the ventilation path passes, and adjacent among the plurality of porous bodies. A plurality of matching porous bodies are used as one group of porous bodies, and the first and second electrodes arranged outside the porous bodies located at both ends of each porous body group, and the first of each porous body group High voltage applying means for applying a high voltage between the electrode and the second electrode to generate plasma in the through holes of the porous body and the space between the porous bodies, and a plurality of types of processing target gases that affect the generation of the plasma The environmental element detecting means for detecting the status of at least two kinds of environmental elements among the wind speed, humidity, temperature, concentration and abnormal discharge in the porous body as the environmental element of the processing object, and detected by the environmental element detecting means Based on the status of multiple types of environmental elements The current plasma generation status is determined for each environmental element, the current plasma generation status determination result for each environmental element is comprehensively determined, and a high voltage is applied based on this comprehensive determination result. Control means for controlling application of a high voltage between the first electrode and the second electrode from the means is provided.

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 applied between the second electrode and between the first electrode and the second electrode of the second porous body group. Application of a high voltage applied between the first electrode and the second electrode of the first porous body group and the second porous body group is controlled by the control means. In this case, the control means for each environmental element based on the status of a plurality of types of environmental elements ( for example, wind speed, temperature, humidity ) of the gas to be processed that affects the generation of plasma detected by the environmental element detection means. The current plasma generation status (for example, insufficient capability, appropriate capability, excessive capability, etc.) is judged, and the judgment result of the current plasma generation status for each environmental element is comprehensively judged, and this comprehensive judgment is made. The application of a high voltage between the first electrode and the second electrode is controlled based on the result.

In this case, there are a first electrode and a second electrode arranged for the first porous body group, and a first electrode and a second electrode arranged for the second porous body group. However, the second electrode disposed with respect to the first porous body group and the first electrode disposed with respect to the second porous body group may be used as a common electrode.
Moreover, in this invention, the porous body should just have many through-holes through which process object gas passes, and the through-hole does not necessarily need to be provided in the shape of a honeycomb.

  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 for each porous body group need only be two electrodes, that is, an upstream electrode and a downstream electrode, so that it is not necessary to arrange electrodes for each porous body, the number of parts is reduced, and the structure is simple. Therefore, the number of assembly steps can be reduced.

In the present invention, the control means controls the application of the high voltage between the first electrode and the second electrode from the high voltage application means based on the comprehensive judgment result of the plasma generation state. The following method is conceivable as a method for obtaining a comprehensive determination result of the plasma generation state.
(1) For each environmental element, it is determined whether the current plasma generation status is inadequate capacity, appropriate capacity, or excessive capacity, and the current plasma generation status determination result for each environmental element is determined for each environmental element. Comprehensive determination is made according to the priority set between the environmental elements, and application of a high voltage between the first electrode and the second electrode from the high voltage applying means is performed based on the comprehensive determination result. Control (priority method).
(2) For each environmental element, determine whether the current plasma generation status corresponds to insufficient capability, appropriate capability, or excess capability, and determine the current plasma generation status for each environmental component. Comprehensive judgment is made according to the number corresponding to each item of deficiency, appropriate capacity, and excess capacity, and based on this comprehensive determination result, the high voltage application means is connected between the first electrode and the second electrode. Controls the application of high voltage (voting method).
(3) For each environmental element, determine whether the current plasma generation status corresponds to insufficient capability, appropriate capability, or excessive capability, and determine the current plasma generation status determination result for each environmental component. The determination result is comprehensively determined by multiplying the weight determined for each environmental element, and based on the comprehensive determination result, the high voltage applying means is connected to the first electrode and the second electrode. Controls the application of high voltage (weighting method).

In the present invention, the control means controls the application of the high voltage between the first electrode and the second electrode from the high voltage application means based on the comprehensive judgment result of the plasma generation state. The following method can be considered as a control method according to the comprehensive judgment result of the plasma generation state at that time.
(1) A positive voltage (+ V) rising in the positive direction from the ground potential is applied to the first electrode, and a negative voltage (−V) falling in the negative direction from the ground potential is alternately applied to the second electrode. If the application of high voltage between the first electrode and the second electrode is controlled while it is determined from the comprehensive judgment result that the plasma generation capacity needs to be increased, the first electrode The first electrode and the second electrode are overlapped so that the state in which the applied positive voltage rises in the positive direction and the state in which the negative voltage applied to the second electrode falls in the negative direction partially overlap. Control the application of high voltage between them . As a result, the difference applied between the first electrode and the second electrode during the period in which the rising state of the positive voltage to the first electrode and the falling state of the negative voltage to the second electrode overlap. The voltage becomes a double voltage (2V = + V − (− V)), the plasma generation state becomes more active, and the plasma generation capability increases.
(2) The positive voltage (+ V) rising in the positive direction from the ground potential is applied to the first electrode, and the negative voltage (−V) falling in the negative direction from the ground potential is alternately applied to the second electrode. When the application of a high voltage between the first electrode and the second electrode is controlled while it is determined from the comprehensive determination result that the plasma generation capability needs to be reduced, the first electrode The first electrode and the second electrode are overlapped so that the state in which the applied positive voltage falls to the ground potential and the state in which the negative voltage applied to the second electrode rises to the ground potential partially overlap. Control the application of high voltage between them . 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 plasma generation capability decreases.

  According to the present invention, the status of a plurality of types of environmental elements of the gas to be processed that affects the generation of plasma is detected, and the current plasma is detected for each environmental element based on the status of the detected types of environmental elements. Of the current plasma generation state for each environmental element is comprehensively determined. Based on the comprehensive determination result, the first electrode and the first electrode from the high voltage applying means are determined. Since the application of a high voltage between the two electrodes is controlled, the application of the high voltage is controlled based on a comprehensive judgment result considering the judgment result of the plasma generation status for each environmental element. Therefore, it is possible to appropriately adjust the gas processing capacity with respect to changes in a plurality of types of environmental elements of the processing target gas that affect the generation of plasma.

It is a figure which shows the principal part of the reference example (reference example 1) before going into description of one Embodiment of the gas processing apparatus which concerns on this invention. 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. 10 is a time chart showing changes in applied voltage to the electrodes of the honeycomb structure when the delay time TC1 and the advance time TC2 of the ON timing of the drive pulse PS2 with respect to the ON timing of the drive pulse PS1 are set to zero. FIG. 4 is a diagram illustrating 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. 3. FIG. 4 is a diagram for explaining 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. 3. 10 is a time chart showing a change in voltage applied to the electrodes of the honeycomb structure when a delay time TC1 of the ON timing of the drive pulse PS2 with respect to the ON timing of the drive pulse PS1 is TC1> 0. 10 is a time chart showing a change in voltage applied to the electrodes of the honeycomb structure when the on-timing time TC2 of the driving pulse PS2 with respect to the on-timing of the driving pulse PS1 is TC2> 0. It is a flowchart which shows operation | movement at the time of making it obtain | require the comprehensive judgment result of the generation condition of a plasma by a priority system in the control part of this gas processing apparatus. It is a figure which shows the judgment logic at the time of trying to obtain the comprehensive judgment result of the generation condition of a plasma by a voting method in the control part of this gas processing apparatus. It is a figure which shows the relationship between the value of the capability control reference value C at the time of obtaining the comprehensive judgment result of the generation state of a plasma by a weighting method in the control part of this gas processing apparatus, and a comprehensive judgment result. It is a figure which shows the principal part of another reference example (reference example 2) of the gas processing apparatus which concerns on this invention. It is a figure which shows the principal part of another reference example (reference example 3) of the gas processing apparatus which concerns on this invention. 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 figure which shows the principal part of other embodiment (Embodiment 2) of the gas processing apparatus which concerns on this invention. It is a time chart which shows the example which adjusted the delay time TD1 of the off timing of drive pulse PS1 with respect to the off timing of drive pulse PS2. It is a time chart which shows the example which adjusted the advance time TD2 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.
[ Reference Example 1 ]
FIG. 1 is a diagram showing a main part of a reference example (reference example 1) before the description of an embodiment of a gas processing apparatus according to the present invention. In this figure, the same reference numerals as those in FIG. 17 denote the same or equivalent components as those described with reference to FIG. 17, and the description thereof will be omitted.

In Reference Example 1 , the honeycomb structure 4 is disposed in the duct 1, the first electrode 8 and the second electrode 9 are disposed on one and the other sides of the honeycomb structure 4, and the first electrode 8 is disposed. 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 Reference Example 1 , a wind speed sensor 21 that detects the wind speed of the processing target gas GS upstream of the honeycomb structure 4, a humidity sensor 22 that detects the humidity of the processing target gas GS, and the temperature of the processing target gas GS. And a temperature of the processing target gas GS detected by the wind speed sensor 21, a humidity of the processing target gas GS detected by the humidity sensor 22, and a temperature of the processing target gas GS detected by the temperature sensor 23. This is given to the control unit CNT.

Controller CNT has a hardware composed of a processor and a storage device, in cooperation with these hardware is realized by a program for realizing various functions, the output function of driving dynamic pulse PS1, PS2.

  In this example, the drive pulse PS1 with the time width TW1 is given to the base of the transistor Q2 from the output terminal O1 of the control unit CNT at a predetermined cycle, and the drive pulse PS2 with the time width TW2 is used for switching from the output terminal O2 of the control unit CNT. It is given to the integrated circuit IC2 at a predetermined cycle.

  Further, as shown in FIG. 2A, the driving 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 the driving pulse PS1 is driven as shown in FIGS. The on-timing of the driving pulse PS2 with respect to the on-timing of the pulse PS1 is automatically adjusted based on the comprehensive judgment result of the plasma generation state described later.

In this case, the adjustment amount of the on-timing of the driving pulse PS2 with respect to the on-timing of the driving pulse PS1 is TC, and the adjustment amount in the direction of delaying with respect to the on-timing of the driving pulse PS1 is the delay time TC1. The adjustment amount is set to advance time TC2. In the first reference example , the switching integrated circuits IC1 and IC2 use “494” type switching control ICs.

[Operation in the case where the delay time TC1 and the advance time TC2 of the ON timing of the drive pulse PS2 are 0 (TC1, TC2 = 0 (TC = 0))]
FIG. 3 shows changes in applied voltage to the electrodes 8 and 9 of the honeycomb structure 4 when the delay time TC1 and the advance time TC2 of the ON timing of the drive pulse PS2 are set to zero.

  In the high voltage applying unit 20, when the drive pulse PS1 from the output terminal O1 of the control unit CNT becomes the “H” level (FIG. 3A: 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. 4). 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. 3B: 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. 3 (c): t1 point), 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. 3 (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. 3 (c): 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. 5). 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. 3 (d): 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. 3A: 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. 3B: 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 delay time TC1 and the advance time TC2 of the ON timing of the drive pulse PS2 are set to 0, the first electrode 8 and the second electrode at the ON timing and the OFF timing of the drive pulses PS1 and PS2. 9, the difference voltage V1 + V2 between the positive voltage + V1 and the negative voltage −V2 is instantaneously applied.

  In this example, V1 and V2 are set to high voltages (V1 = V2 = V) of several kV to several tens of kV, and a double voltage 2V is instantaneously applied at the on timing and off timing of the drive pulses PS1 and PS2. And As a result, plasma is generated in the through-holes 4a of the honeycomb structure 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 case, plasma is generated because the high voltage V is applied even during periods other than the on timing and off timing of the drive pulses PS1 and PS2.

[Operation when the delay time TC1 of the ON timing of the drive pulse PS2 is TC1> 0]
If the control unit CNT determines that it is necessary to increase the plasma generation capability from the control state of TC1, TC2 = 0 shown in FIG. 3, the control unit CNT sets the delay time TC1 according to the required amount of the plasma generation capability at that time. Increase (TC1> 0). Whether or not it is necessary to increase the plasma generation capability at this time is determined by the wind speed of the processing target gas GS detected by the wind speed sensor 21, the humidity of the processing target gas GS detected by the humidity sensor 22, and the temperature sensor 23. This is performed based on the temperature of the processing target gas GS to be detected.

  In this case, based on the wind speed of the processing target gas GS detected by the wind speed sensor 21, the control unit CNT corresponds to the current plasma generation state of “insufficient capacity”, “appropriate capacity”, or “excess capacity”. Determine whether. Further, based on the humidity of the processing target gas GS detected by the humidity sensor 22, it is determined whether the current plasma generation state corresponds to “insufficient capability”, “appropriate capability”, or “excess capability”. Further, based on the temperature of the processing target gas GS detected by the temperature sensor 23, it is determined whether the current plasma generation state corresponds to “insufficient capability”, “appropriate capability”, or “excess capability”. Then, the judgment result of the current plasma generation status based on the wind speed, the judgment result of the current plasma generation status based on the humidity, and the judgment result of the current plasma generation status based on the temperature are comprehensively judged, Based on this comprehensive determination result, it is determined whether or not it is necessary to increase the plasma generation capability. As a method for obtaining a comprehensive judgment result at this time, there are a priority method, a voting method, and a weighting method, which will be described later.

  FIG. 6 shows a change in the voltage applied to the electrodes 8 and 9 of the honeycomb structure 4 when the delay time TC1 of the ON timing of the drive pulse PS2 is TC1> 0.

  In the high voltage applying unit 20, when the drive pulse PS1 from the output terminal O1 of the control unit CNT becomes the “H” level (FIG. 6A: 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. 4). 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. 6B: point t1).

  When the drive pulse PS2 from the output terminal O2 of the control unit CNT becomes “H” level after elapse of TC1 time (FIG. 6 (c): t2 point), the dead time control terminal dc2 of the switching integrated circuit IC2 is It 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. 6 (d): t2 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 positive voltage + V1 applied to the first electrode 8 is maintained for TC1 time. The rising state and the falling state of the negative voltage −V2 to the second electrode 9 overlap, and the difference voltage between the positive voltage + V1 and the negative voltage −V2 is present between the first electrode 8 and the second electrode 9. V1 + V2 is continuously applied. In this case, if V1 = V2 = V, the double voltage 2V is applied between the first electrode 8 and the second electrode 9 for TC1 time.

  When the drive pulse PS2 becomes “L” level in the high voltage application unit 20 (FIG. 6C: point t3), 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. 5). 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. 6D: point t3).

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. 6A: t3 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. 6B: t3 point ).

  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 delay time TC1 of the ON timing of the drive pulse PS2 is TC1> 0, the rising state of the positive voltage + V1 to the first electrode 8 and the negative voltage −V2 to the second electrode 9 During the TC1 time when the falling state overlaps, the differential voltage V1 + V2 between the positive voltage + V1 and the negative voltage −V2 is applied between the first electrode 8 and the second electrode 9, and the through-hole of the honeycomb structure 4 The amount of plasma generated in 4a increases.

[Operation when drive pulse PS2 ON timing advance time TC2 is TC2> 0]
When the control unit CNT determines that it is necessary to reduce the plasma generation capability from the control state of TC1, TC2 = 0 shown in FIG. 3, the control unit CNT sets the advance time TC2 according to the required amount of the plasma generation capability at that time. Increase (TC2> 0). Whether or not it is necessary to reduce the plasma generation capability at this time is determined by the wind speed of the processing target gas GS detected by the wind speed sensor 21, the humidity of the processing target gas GS detected by the humidity sensor 22, and the temperature sensor 23. This is performed based on the temperature of the processing target gas GS to be detected.

  In this case, based on the wind speed of the processing target gas GS detected by the wind speed sensor 21, the control unit CNT corresponds to the current plasma generation state of “insufficient capacity”, “appropriate capacity”, or “excess capacity”. Determine whether. Further, based on the humidity of the processing target gas GS detected by the humidity sensor 22, it is determined whether the current plasma generation state corresponds to “insufficient capability”, “appropriate capability”, or “excess capability”. Further, based on the temperature of the processing target gas GS detected by the temperature sensor 23, it is determined whether the current plasma generation state corresponds to “insufficient capability”, “appropriate capability”, or “excess capability”. Then, the judgment result of the current plasma generation status based on the wind speed, the judgment result of the current plasma generation status based on the humidity, and the judgment result of the current plasma generation status based on the temperature are comprehensively judged, Based on this comprehensive determination result, it is determined whether or not it is necessary to reduce the plasma generation capability. As a method for obtaining a comprehensive determination result at this time, there are a priority method, a voting method, and a weighting method (described later).

  FIG. 7 shows changes in applied voltage to the electrodes 8 and 9 of the honeycomb structure 4 when the on-timing advance time TC2 of the drive pulse PS2 is TC2> 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).

Then, after the elapse of TC2 time, when the drive pulse PS1 from the output terminal O1 of the control unit CNT becomes the “H” level (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. 4). 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 TC2 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 for approximately TC2 time from when the drive pulse PS2 rises to the “H” level to when 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. 5). 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.

In this way, when the on-timing advance time TC2 of the drive pulse PS2 is TC2> 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. At the time of 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 TC2 hours. The state overlaps and no voltage is applied between the first electrode 8 and the second electrode 9, and the amount of plasma generated in the through-holes 4a of the honeycomb structure 4 is defined as a high voltage pause period. Decrease. 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. Gas treatment can be performed.

[Priority method]
FIG. 8 shows a flowchart when the control unit CNT obtains a comprehensive determination result of the plasma generation state by the priority method. In adopting this priority method, the wind speed of the processing target gas GS detected by the wind speed sensor 21, the humidity of the processing target gas GS detected by the humidity sensor 22, and the processing detected by the temperature sensor 23. A priority is determined between the target gas GS and the temperature. In this example, “wind speed” is given priority 1, “humidity” is given priority 2, and “temperature” is given priority 3.

  In this case, the control unit CNT first determines the current plasma generation state based on the wind speed of the processing target gas GS detected by the wind speed sensor 21 with priority 1 (step S101). Then, it is determined whether the current plasma generation status based on the wind speed corresponds to “insufficient capability”, “appropriate capability”, or “excess capability” (step S102). The generation capability is increased (step S108), and if it is “overcapacity”, the generation capability of plasma is decreased (step S109).

  If the current plasma generation status based on the wind speed is “appropriate capability”, the control unit CNT determines the current plasma generation status based on the humidity of the processing target gas GS detected by the humidity sensor 22 of priority 2. Judgment is made (step S103). Then, it is determined whether the current plasma generation state based on the humidity corresponds to “insufficient capability”, “appropriate capability”, or “excess capability” (step S104). The generation capability is increased (step S108), and if it is “overcapacity”, the generation capability of plasma is decreased (step S109).

  If the current plasma generation status based on humidity is “appropriate capability”, the control unit CNT determines the current plasma generation status based on the temperature of the processing target gas GS detected by the temperature sensor 23 with priority 3. Judgment is made (step S105). Then, it is determined whether the current plasma generation state based on this temperature corresponds to “insufficient capability”, “appropriate capability”, or “excess capability” (step S106). The generation capability is increased (step S108). If “capacity is excessive”, the plasma generation capability is decreased (step S109). If “capability is appropriate”, the current plasma generation capability is maintained (step S107).

[Voting method]
FIG. 9 shows determination logic when the control unit CNT obtains a comprehensive determination result of the plasma generation state by a voting method.

  In this voting method, the determination result of the current plasma generation state based on the wind speed of the processing target gas GS detected by the wind speed sensor 21 and the current plasma based on the humidity of the processing target gas GS detected by the humidity sensor 22. It is assumed that the determination result of the generation status and the determination result of the current plasma generation status based on the temperature of the processing target gas GS detected by the temperature sensor 23 have the same weight.

  In this voting method, the control unit CNT examines the individual judgment result of each sensor as to which item “insufficient ability”, “appropriate ability”, or “excess ability” corresponds, and the number corresponding to each item is the maximum. A comprehensive judgment result is obtained from the item of In this case, if the number corresponding to “insufficient ability” is the maximum, the overall judgment result is “capacity increase”, and if the number corresponding to “overcapacity” is the maximum, the overall judgment result is “ “Capacity reduction”. If the number corresponding to “appropriate ability” is the maximum, the overall judgment result is “maintain current”. In addition, when the three items are the same number, the overall judgment result is “maintain current” as a special rule.

  In this example, there are three types of environmental elements of the processing target gas that affect the generation of plasma: wind speed, temperature, and humidity, and the status of these three types of environmental elements is detected. , Temperature and humidity are not limited to three types. For example, the concentration of the gas to be processed, abnormal discharge in the honeycomb structure, and the like are also considered as environmental factors. When the types of environmental elements of the gas to be processed increase, two items may be generated as the maximum number. In such a case, as a special rule, if the number of “overcapacity” and “appropriate ability” is the same, the overall judgment result is “decreased ability”. The overall judgment result is “capacity increase”, and when “overcapacity” and “capability shortage” are the same number, the overall judgment result is “maintain current”.

[Weighting method]
FIG. 10 shows the relationship between the ability control reference value C (described later) and the overall judgment result when the control unit CNT obtains the overall judgment result of the plasma generation state by the weighting method.

  In this weighting method, the wind speed of the processing target gas GS detected by the wind speed sensor 21, the humidity of the processing target gas GS detected by the humidity sensor 22, and the temperature of the processing target gas GS detected by the temperature sensor 23 are individually set. A weight Wi (0 <Wi <1) is determined in advance. In this case, the sum of the weights Wi is 1 (ΣWi = 1).

  In this weighting method, when the determination result of the current plasma generation state based on the wind speed of the processing target gas GS detected by the wind speed sensor 21 is “overcapacity”, the control unit CNT determines the weight determined for the wind speed. A value obtained by multiplying Wi by k = −1 is set as an individual determination result Ri = Wi × k = −Wi. Similarly, when the determination result of the current plasma generation state based on the humidity of the processing target gas GS detected by the humidity sensor 22 is “overcapacity”, k = −1 is set to the weight Wi determined for the humidity. If the result of determination of the current plasma generation state based on the temperature of the processing target gas GS detected by the temperature sensor 23 is “overcapacity”, the individual determination result Ri = Wi × k = −Wi Is obtained by multiplying the weight Wi determined for k by −1 as an individual determination result Ri = Wi × k = −Wi.

  In addition, when the determination result of the current plasma generation state based on the wind speed of the processing target gas GS detected by the wind speed sensor 21 is “appropriate capability”, the control unit CNT sets the weight Wi determined for the wind speed to k. Multiplication of = 0 is set as an individual determination result Ri = Wi × k = 0. Similarly, when the determination result of the current plasma generation state based on the humidity of the processing target gas GS detected by the humidity sensor 22 is “appropriate capability”, the weight Wi determined for the humidity is multiplied by k = 0. In the case where the individual determination result Ri = Wi × k = 0 and the determination result of the current plasma generation state based on the temperature of the processing target gas GS detected by the temperature sensor 23 is “capability appropriate”, The weight Wi determined by multiplying k = 0 is set as the individual determination result Ri = Wi × k = 0.

  In addition, when the determination result of the current plasma generation state based on the wind speed of the processing target gas GS detected by the wind speed sensor 21 is “insufficient”, the control unit CNT sets the weight Wi determined for the wind speed to k. = + 1 is multiplied by individual determination result Ri = Wi × k = + Wi. Similarly, when the determination result of the current plasma generation state based on the humidity of the processing target gas GS detected by the humidity sensor 22 is “insufficient”, the weight Wi determined for the humidity is multiplied by k = + 1. If the determination result of the current plasma generation state based on the temperature of the processing target gas GS detected by the temperature sensor 23 is “insufficient”, the individual determination result Ri = Wi × k = + Wi. Multiplying the determined weight Wi by k = + 1 is defined as an individual determination result Ri = Wi × k = + Wi.

  Then, the control unit CNT integrates all the individual determination results Ri thus determined, and determines the integrated value of the individual determination results Ri as a capability control reference value C (C = Σ (Wi × k)). The capability control reference value C is −1 ≦ C ≦ + 1. The relationship between the capability control reference value C and the overall determination result is determined as shown in FIG. In FIG. 10, m is a value of 0 ≦ m <1.

  In accordance with the relationship shown in FIG. 10, the control unit CNT sets the overall determination result to “decrease capability” when the capability control reference value C is −1 ≦ C <−m, and the capability control reference value C is −m. When ≦ C ≦ m, the comprehensive determination result is “maintain current”, and when the ability control reference value C is m <C ≦ + 1, the comprehensive determination result is “capacity increase”.

[ Reference Example 2 ]
In Reference Example 1 , 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. 11 shows an example ( Reference Example 2 ) in which a plurality of honeycomb structures 4 are arranged in the duct 1. In Reference Example 2 , the honeycomb structure 4 (4-1 to 4-3) is arranged in the duct 1 with 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 upstream of the honeycomb structure 4-1 disposed upstream of the honeycomb structure 4, and the downstream of the honeycomb structure 4-3 disposed downstream. The second electrode (downstream electrode) 9 is arranged on the side, the upstream 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 downstream electrode 9 is applied by the conducting wire 17 to the high voltage. The negative voltage supply terminal T2 of the unit 20 is connected. The high voltage application unit 20 is the same as that used in Reference Example 1 .

In Reference Example 2 , 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 Reference Example 1 , based on the comprehensive determination result of the plasma generation state, between the upstream electrode (first electrode) 8 and the downstream electrode (second electrode) 9. The difference voltage V1 + V2 between the positive voltage + V1 and the negative voltage −V2 is applied while the application time is automatically adjusted, or the high voltage pause period is automatically adjusted alternately between the positive voltage + V1 and the negative voltage −V2. Applied. By applying this high voltage, plasma is generated in the through-holes 4a of the honeycomb structure 4 and the space gap 12 between the honeycomb structures 4, and is included in the processing target gas GS by ions and radicals generated in the plasma. Hazardous gases are broken down into harmless substances.

  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 treatment 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.

[ Reference Example 3 ]
In Reference Example 2 , a plurality of honeycomb structures 4 are provided in the duct 1 along the direction from the inlet to the outlet of the duct 1, but as shown in FIG. 12, the direction from the inlet to the outlet of the duct 1 A plurality of honeycomb structures 4 may be provided in the duct 1 along a direction perpendicular to the duct 1.

  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 1 ]
FIG. 13 shows a main part of an embodiment ( Embodiment 1 ) of a gas processing apparatus according to the present invention. In the first 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 8 as the first electrode and the electrode 9 as the second electrode are arranged.

  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. The electrode 10 as the first electrode and the electrode 9 as the second electrode are disposed outside the honeycomb structures 4-3 and 4-3 located in the area.

In the first embodiment , the electrode 9 is a common electrode that serves as both the second electrode of the first honeycomb structure group 4A and the second electrode of the second honeycomb structure group 4B. The second electrode of the first honeycomb structure group 4A and the second electrode of the second honeycomb structure group 4B may be independent electrodes.

The electrodes 8, 9 and 10 are made of metal mesh so that the gas to be processed GS passes through. In the first embodiment , the electrodes 8 and 10 are connected to the positive voltage supply terminal T1 of the high voltage application unit 20 by the conductive wires 16 and 18, and the electrode 9 is connected to the negative voltage supply terminal of the high voltage application unit 20 by the conductive wire 17. The connection is made to T2. The high voltage application unit 20 is the same as that used in Reference Example 1 .

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 Reference Example 1 , based on the overall determination result of the plasma generation state, the first honeycomb structure 4A between the first electrode 8 and the second electrode 9 and the first The difference voltage V1 + V2 between the positive voltage + V1 and the negative voltage −V2 is applied between the first electrode 10 and the second electrode 9 of the second honeycomb structure group 4B while the application time is automatically adjusted, The positive voltage + V1 and the negative voltage −V2 are alternately applied while the high voltage pause period is automatically adjusted. By applying this high voltage, plasma is generated in the through-holes 4a of the honeycomb structure 4 and the space gap 12 between the honeycomb structures 4, and is included in the processing target gas GS by ions and radicals generated in the plasma. Hazardous gases are broken down into harmless substances.

  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, a high voltage application unit 20 is provided separately for the first honeycomb structure group 4A and the second honeycomb structure group 4B, and a high voltage applied to the first honeycomb structure group 4A. The voltage (VA) and the high voltage (VB) applied to the second honeycomb structure group 4B may have different values. 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 2 ]
FIG. 14 shows a main part of another embodiment (Embodiment 2) of the gas treatment apparatus according to the present invention. In the second 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 8 as the first electrode and the electrode 9 as the second electrode are arranged.

  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. The electrode 10 as the first electrode and the electrode 9 as the second electrode are disposed outside the honeycomb structures 4-3 and 4-3 located in the area.

  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. Outside the honeycomb structures 4-5 and 4-6, the electrode 10 is disposed as the first electrode, and the electrode 11 is disposed as the second electrode.

In the second embodiment , the electrode 9 is a common electrode that serves as both the second electrode of the first honeycomb structure group 4A and the second electrode of the second honeycomb structure group 4B. The second electrode of the first honeycomb structure group 4A and the second electrode of the second honeycomb structure group 4B may be independent electrodes. The electrode 10 is a common electrode that serves as both the first electrode of the second honeycomb structure group 4B and the first electrode of the third honeycomb structure group 4C. The first electrode of the group 4B and the first electrode of the third honeycomb structure group 4C may be independent electrodes.

The electrodes 8, 9, 10 and 11 are made of metal mesh so that the processing target gas GS can pass therethrough. In the second embodiment , the electrodes 8 and 10 are connected to the positive voltage supply terminal T1 of the high voltage applying unit 20 by the conducting wires 16 and 18, and the electrodes 9 and 11 are connected to the positive voltage supplying unit 20 by the conducting wires 17 and 19. The negative voltage supply terminal T2 is connected. The high voltage application unit 20 is the same as that used in Reference Example 1 .

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 Reference Example 1 , based on the comprehensive determination result of the plasma generation state, the first electrode 8 and the second electrode 9 of the first honeycomb structure group 4A are Positive voltage between the first electrode 10 and the second electrode 9 of the second honeycomb structure group 4B and between the first electrode 10 and the second electrode 11 of the third honeycomb structure group 4C. The difference voltage V1 + V2 between + V1 and negative voltage −V2 is applied while the application time is automatically adjusted, or the positive voltage + V1 and negative voltage −V2 are alternately applied while the high voltage pause period is automatically adjusted. To do. By applying this high voltage, plasma is generated in the through-holes 4a of the honeycomb structure 4 and the space gap 12 between the honeycomb structures 4, and is included in the processing target gas GS by ions and radicals generated in the plasma. Hazardous gases are broken down into harmless substances.

  In this gas treatment apparatus, the first electrode 10 and the second electrode 9 of the second honeycomb structure group 4B are disposed between the first electrode 8 and the second electrode 9 of the first honeycomb structure group 4A. And a high voltage is individually applied between the first electrode 10 and the second electrode 11 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 application unit 20 is provided separately for the first honeycomb structure group 4A, the second honeycomb structure group 4B, and the third honeycomb structure group 4C, A high voltage (VA) applied to the honeycomb structure group 4A, a high voltage (VB) applied to the second honeycomb structure group 4B, and a high voltage (VC) applied to the third honeycomb structure group 4C; May be set to different values. 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.

In the first and second embodiments 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. 13, 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.

In the first and second embodiments described above, the gap G (G1, G2, G3) between the honeycomb structures 4 is made equal, but it may be made different. For example, in the configuration shown in FIG. 14, if the gaps G1, G2, and G3 between the honeycomb structures 4 are made different, the amount of plasma generated in the space gaps 12-1, 12-2, and 12-3 becomes 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.

In the first and second embodiments described above, the honeycomb structure 4 may be provided with a catalytic function for decomposing ozone. For example, in the configuration shown in FIG. 13, the downstream position of the honeycomb structure 4-4. A catalyst for decomposing ozone may be provided.

In Reference Examples 2 and 3 (FIGS. 11 and 12) described above, the number of honeycomb structures 4 is not limited as long as it is two or more. In the first embodiment (FIG. 13) described above, the number of honeycomb structures 4 is not limited as long as two or more honeycomb structure groups can be formed. In the second embodiment (FIG. 14), an example in which three honeycomb structure groups are provided is shown as a modification of the first embodiment .

Further, in the first and second embodiments described above, a large amount of ozone may be generated as a by-product and used as an ozone generator.
Further, in the first and second embodiments described above, the honeycomb structure 4 is provided with the through holes 4a in a honeycomb shape, but it is only necessary to have a large number of through holes 4a, and the honeycomb structure 4 is limited to the honeycomb shape. is not.

In the first and second embodiments described above, the delay time TC1 of the ON timing of the drive pulse PS2 with respect to the ON timing of the drive pulse PS1 is adjusted. However, as shown in FIG. 15, the OFF timing of the drive pulse PS2 The delay time TD1 of the off timing of the drive pulse PS1 with respect to may be adjusted.

In the first and second embodiments described above, the advance time TC2 of the ON timing of the drive pulse PS2 with respect to the ON timing of the drive pulse PS1 is adjusted. However, as shown in FIG. 16, the OFF timing of the drive pulse PS2 The advance time TD2 of the off timing of the drive pulse PS1 with respect to may be adjusted.

  The delay time TC1 of the on timing of the drive pulse PS2 with respect to the on timing of the drive pulse PS1 and the delay time TD1 of the off timing of the drive pulse PS1 with respect to the off timing of the drive pulse PS2 may both be adjusted. The on-timing advance time TC2 of the driving pulse PS2 with respect to the on-timing of PS1 and the off-timing advance time TD2 of the driving pulse PS1 with respect to the off-timing of the driving pulse PS2 may be adjusted together.

In the first and second embodiments described above, the application time of the differential voltage V1 + V2 between the positive voltage + V1 and the negative voltage -V2 is automatically adjusted based on the comprehensive determination result of the plasma generation state, or the positive voltage The high voltage pause period when + V1 and negative voltage -V2 are applied alternately is adjusted automatically. However, the high voltage value applied between the electrodes is automatically adjusted or applied between the electrodes. The frequency of the high voltage to be automatically adjusted may be used.

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, 8-11 ... Electrode, 12 ( 12-1 to 12-3) ... space gap, 16 to 19 ... conductor, G (G1 to G3) ... interval, GS ... gas to be processed, 20 ... high voltage application unit, 21 ... wind speed sensor, 22 ... humidity sensor, 23 ... Temperature sensor, TR1, TR2 ... Transformer, D1, D2, D3, D4 ... Diode, C1, C2 ... Capacitor, Q1, Q2, Q3 ... Transistor, R1, R2, R3 ... Resistance, T1 ... Positive voltage supply terminal, T2 ... negative voltage supply terminal, IC1, IC2 ... switching integrated circuit, CNT ... control unit.

Claims (6)

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 applying means for applying a high voltage between the first electrode and the second electrode of each porous body group to generate plasma in the through hole of the porous body and the space between the porous bodies;
Status of at least two types of environmental elements among the wind speed, humidity, temperature, concentration, and abnormal discharge in the porous body as the plurality of types of environmental elements of the processing target gas that affect the generation of the plasma Environmental element detecting means for detecting
Based on the status of a plurality of types of environmental elements detected by the environmental element detection means, the current plasma generation status is determined for each environmental element, and the current plasma generation status determination result for each environmental element And a control means for controlling application of a high voltage between the first electrode and the second electrode from the high voltage application means based on the comprehensive judgment result. A gas processing apparatus characterized by that. The gas treatment device according to claim 1, wherein
The control means includes
For each environmental element, it is determined whether the current plasma generation status corresponds to insufficient capability, appropriate capability, or excessive capability, and the determination result of the current plasma generation status for each environmental element is determined as each environmental element. A comprehensive determination is made according to the priority set between them, and the application of the high voltage between the first electrode and the second electrode from the high voltage applying means is performed based on the comprehensive determination result. A gas processing apparatus characterized by controlling . The gas treatment device according to claim 1, wherein
The control means includes
For each environmental element, it is determined whether the current plasma generation status corresponds to insufficient capability, appropriate capability, or excessive capability, and the determination result of the current plasma generation status for each environmental element is used as the determination result. The overall judgment is made according to the number of the environmental elements determined to fall under the shortage, the number of the environmental elements judged to fall under the capacity suitability, and the number of the environmental elements judged to fall under the overcapacity. A gas processing apparatus that controls application of a high voltage between the first electrode and the second electrode from the high voltage applying means based on a determination result . The gas treatment device according to claim 1, wherein
The control means includes
For each environmental element, it is determined whether the current plasma generation status corresponds to insufficient capability, appropriate capability, or excessive capability, and the determination result of the current plasma generation status for each environmental element is the determination result. Is multiplied by a weight determined for each environmental element, and based on the comprehensive determination result, the high voltage applying means is connected to the first electrode and the second electrode from the high voltage applying means. A gas processing apparatus characterized by controlling application of a high voltage. In the gas treatment device according to any one of claims 1 to 4 ,
The control means includes
A positive voltage rising in the positive direction from the ground potential is applied to the first electrode, and a negative voltage falling in the negative direction from the ground potential is alternately applied to the second electrode. While controlling the application of high voltage to and from the electrode,
When it is determined from the comprehensive determination result that it is necessary to increase the generation capacity of the plasma,
The first voltage is applied so that the positive voltage applied to the first electrode rises in the positive direction and the negative voltage applied to the second electrode falls in the negative direction. A gas processing apparatus that controls application of a high voltage between an electrode and a second electrode . In the gas treatment device according to any one of claims 1 to 4 ,
The control means includes
A positive voltage rising in the positive direction from the ground potential is applied to the first electrode, and a negative voltage falling in the negative direction from the ground potential is alternately applied to the second electrode. While controlling the application of high voltage to and from the electrode,
When it is determined from the comprehensive determination result that it is necessary to reduce the plasma generation capability,
The state where the positive voltage applied to the first electrode falls to the ground potential and the state where the negative voltage applied to the second electrode rises to the ground potential partially overlap. A gas processing apparatus that controls application of a high voltage between an electrode and a second electrode .

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