WO2010074195A1 - Pulse discharge generating method and apparatus - Google Patents

Pulse discharge generating method and apparatus Download PDF

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Publication number
WO2010074195A1
WO2010074195A1 PCT/JP2009/071531 JP2009071531W WO2010074195A1 WO 2010074195 A1 WO2010074195 A1 WO 2010074195A1 JP 2009071531 W JP2009071531 W JP 2009071531W WO 2010074195 A1 WO2010074195 A1 WO 2010074195A1
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Prior art keywords
pulse
discharge
electrode
streamer
electrodes
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PCT/JP2009/071531
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French (fr)
Japanese (ja)
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隆男 浪平
秀典 秋山
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Namihira Takao
Akiyama Hidenori
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Priority to JP2010544141A priority Critical patent/JP5745858B2/en
Publication of WO2010074195A1 publication Critical patent/WO2010074195A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/48—Sulfur compounds
    • B01D53/50—Sulfur oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/32—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by electrical effects other than those provided for in group B01D61/00
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/72—Organic compounds not provided for in groups B01D53/48 - B01D53/70, e.g. hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
    • C01B13/10—Preparation of ozone
    • C01B13/11—Preparation of ozone by electric discharge
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/10—Oxidants
    • B01D2251/102—Oxygen
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2256/00—Main component in the product gas stream after treatment
    • B01D2256/14—Ozone
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/70—Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
    • B01D2257/708—Volatile organic compounds V.O.C.'s
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/80—Employing electric, magnetic, electromagnetic or wave energy, or particle radiation
    • B01D2259/818—Employing electrical discharges or the generation of a plasma

Definitions

  • the present invention relates to a discharge generation method and apparatus.
  • Non-thermal equilibrium plasma formed by electron beam and electrical discharge is purified from combustion exhaust gas such as nitrogen oxide (NO X ) and sulfur oxide (SO X ) treatment and volatility due to its high chemical activity.
  • combustion exhaust gas such as nitrogen oxide (NO X ) and sulfur oxide (SO X ) treatment and volatility due to its high chemical activity.
  • NO X nitrogen oxide
  • SO X sulfur oxide
  • a wide range of applications are expected, such as purification of industrial exhaust gases, such as treatment of organic compounds (VOCs), and generation of ozone (O 3 ), which is expected to be used as the next-generation oxidant. .
  • the low energy efficiency is a big barrier, and there are not many practical examples.
  • one of the keys to improving energy efficiency is how to prevent the discharge from being transferred to arc discharge (also called spark discharge) which is a kind of thermal equilibrium plasma.
  • arc discharge also called spark discharge
  • a dielectric barrier discharge method also called asexual discharge or ozonizer discharge
  • the pulse discharge method that actively prevents the transition to arc discharge can be mentioned.
  • Fig. 1 shows a block diagram of a non-thermal equilibrium plasma formation system (bottom) using dielectric barrier discharge (top) and pulse discharge.
  • energy is directly injected from the AC power source to the discharge electrode, so the plug-in energy is non-thermally balanced through the discharge electrode at approximately 85% and the energy conversion efficiency of a typical AC power source. It can be injected into the plasma.
  • plug-in energy is converted into a direct current, then converted into a pulse, and further injected into non-thermal equilibrium plasma through a discharge electrode. Therefore, a total of 32% of plug-in energy is consumed by each energy conversion, and the maximum energy injected into the discharge electrode is about 68% of the plug-in energy.
  • Non-Patent Document 1 and Non-Patent Document 2 The inventors of the present application have been studying so-called nanosecond pulse discharge (Non-Patent Document 1 and Non-Patent Document 2), and the present invention uses a nanosecond pulse discharge, so far it has a low energy conversion efficiency. It aims at improving the pulse discharge method which had to stay in this.
  • T. Namihira, D. Wang, S. Katsuki, R. hackam and H. Akiyama “Propagation velocity of pulsed streamer dischargesin atmospheric air”, IEEE Transactions on Plasma Science, Vol.31, No.5, PP.1091-1094 , 2003.
  • T. Namihira, T. Tokuichi, D. Wang, S. Katsuki, H. Akiyama “Characterization of nano-seconds pulsed streamer discharges”, 2007 IEEE PulsedPower and Plasma Science Conference, Albuquerque, USA, pp.572-575, 2007 .
  • the first technical means adopted by the present invention is: Preparing a discharge electrode including a first electrode and a second electrode, and a pulse power source for generating a pulse having a rise time of 10 ns or less; By applying a pulse voltage having a rise time of 10 ns or less between the electrodes, the streamer head is advanced from the first electrode to the second electrode at a constant speed, Corresponding to the distance between the electrodes, by selecting the duration of the pulse, the applied voltage, the discharge is terminated when the developing streamer head reaches the second electrode, Pulse discharge generation method, Or
  • a discharge generator comprising: a discharge electrode comprising a first electrode and a second electrode; and a pulse power supply that generates a pulse having a rise time of 10 ns or less,
  • the pulse power source causes a streamer head to advance at a constant speed from the first electrode to the second electrode by applying a pulse voltage having a rise time of 10 ns or less between the electrodes, The duration of the pulse, the applied voltage is
  • the streamer head is developed at a constant speed during streamer discharge (development between the electrodes of the streamer head).
  • the impedance (“discharge electrode impedance” or “discharge impedance” during discharge) can be kept constant.
  • the rise time of the pulse is 10 ns or less (except 0) (for example, 9 ns, 8 ns, 7 ns, 6 ns, 5 ns, 4 ns, 3 ns, 2 ns, 1 ns, less than 1 ns (excluding 0), or Any numerical value between them can be taken.
  • the pulse rise time is 9 ns or less, in one embodiment, 8 ns or less, and in one embodiment, 7 ns or less. 6 ns or less, one embodiment 5 ns or less, one embodiment 4 ns or less, one embodiment 3 ns or less, one embodiment 2 ns or less, and one embodiment 1 ns or less. .
  • the second technical means adopted by the present invention is: Preparing a discharge electrode including a first electrode and a second electrode, and a pulse power source for generating a pulse having a rise time of 10 ns or less; Applying a pulse voltage having a rise time of 10 ns or less between the electrodes to generate a streamer discharge, and causing the streamer head to advance at a constant speed from the first electrode to the second electrode; By selecting the duration of the pulse and the applied voltage according to the distance between the electrodes, the discharge is terminated within 1.5 times the streamer discharge time.
  • a discharge generator comprising: a discharge electrode comprising a first electrode and a second electrode; and a pulse power supply that generates a pulse having a rise time of 10 ns or less,
  • the pulse power supply generates a streamer discharge by applying a pulse voltage having a rise time of 10 ns or less between the electrodes, and advances the streamer head from the first electrode to the second electrode at a constant speed.
  • the duration of the pulse and the applied voltage are selected to finish the discharge within 1.5 times the streamer discharge time, corresponding to the distance between the electrodes.
  • the discharge is terminated within 1.5 times the streamer discharge time (streamer progress time).
  • the time for glow-like discharge can be reduced, which makes it possible to reduce heat loss during glow-like discharge.
  • the discharge time exceeds 1.5 times the streamer discharge time (streamer progress time)
  • the glow-like discharge time becomes longer and the heat loss reaches a considerable level.
  • a multiple of any numerical value of 1.5 times or less for example, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less. In order to minimize the heat loss during glow-like discharge, it is desirable that this multiple is smaller.
  • this multiple may be less than 1 (that is, the discharge may be terminated before the streamer head reaches the second electrode).
  • the discharge is terminated only by the streamer discharge by terminating the discharge when the progressing streamer head reaches the second electrode (that is, one time the progress time of the streamer).
  • the third technical means adopted by the present invention is: A discharge electrode including a first electrode and a second electrode, and a pulse power source that generates a pulse whose rise time is shorter than the streamer head formation time, By applying a pulse voltage from the pulse power source between the electrodes, a streamer head is developed at a constant speed from the first electrode to the second electrode, Corresponding to the distance between the electrodes, by selecting the duration of the pulse, the applied voltage, the discharge is terminated when the developing streamer head reaches the second electrode, Pulse discharge generation method and apparatus, Or A discharge electrode including a first electrode and a second electrode, and a pulse power source that generates a pulse whose rise time is shorter than the streamer head formation time, A pulse voltage is applied between the electrodes from the pulse power source to generate a streamer discharge, and a streamer head is developed at a constant speed from the first electrode to the second electrode, By selecting the duration of the pulse and the applied voltage according to the distance between the electrodes, the discharge is terminated within 1.5 times the streamer discharge
  • the streamer discharge time is “streamer head formation time” + “streamer head interelectrode progress time”, and the voltage rise time of a conventional general pulse discharge (for example, voltage rise time 40 ns) is greater than the streamer head formation time. Since it is long, the voltage increases during the progress of the streamer head between the electrodes, and as a result, the progress speed of the streamer head changes. On the other hand, since the voltage rise time of nanosecond pulse discharge (voltage rise time is 10 ns or less, for example, voltage rise time 2 ns) is shorter than the streamer head formation time, the voltage rises before the streamer head progresses between the electrodes. When the streamer is progressing, the voltage applied to the electrodes becomes substantially constant, and as a result, the streamer head moves at a constant speed.
  • a conventional general pulse discharge for example, voltage rise time 40 ns
  • the discharge time (at the end of discharge) can be determined by selecting the pulse duration and the applied voltage according to the distance between the electrodes.
  • the “arrival time T of the streamer to the external electrode (second electrode)” is “the distance L between the electrodes” / “the progress rate S of the streamer”, and when the discharge is performed only by the streamer discharge, It is desirable that the voltage be zeroed immediately after the streamer reaches the external electrode, ie, the “pulse duration P” is this T.
  • S depends on the applied voltage V (S increases as V increases), P is not a fixed value. As for the pulse rise and fall rates, the faster the rate, the less likely it will be that the control of determination at the end of the discharge is disturbed.
  • the pulse fall time is less than 10 ns (excluding 0) (for example, less than 9 ns, 8 ns, 7 ns, 6 ns, 5 ns, 4 ns, 3 ns, 2 ns, 1 ns, and 1 ns (0 is Excluding) or any numerical value between them.
  • the first electrode and the second electrode constituting the discharge electrode as a pair are each composed of one or a plurality of electrodes.
  • the first electrode and the second electrode constituting the discharge electrode as a pair include a concentric outer cylindrical electrode and an inner cylindrical or linear electrode.
  • the electrode configuration applicable to the present invention is not limited, and includes wire-to-flat plate, multi-wire paired plate, needle-to-plate, multi-needle to flat plate, and other shapes and arrangements known to those skilled in the art. .
  • the present invention provides a gas processing method for processing a gas to be processed supplied between the electrodes using the pulse discharge generation method, or a method for generating a gap between the electrodes using the pulse discharge generator.
  • a gas processing apparatus configured to process a supplied gas to be processed.
  • the gas to be treated is typically an exhaust gas such as a combustion exhaust gas.
  • the treatment of nitrogen oxide (NO x ) or sulfur oxide (SO x ) is exemplified.
  • the present invention provides an ozone generation method for generating ozone from oxygen or air supplied between the electrodes using the pulse discharge generation method, or the electrode using the pulse discharge generation device.
  • the present invention is provided as an ozone generator configured to generate ozone from oxygen or air supplied therebetween.
  • the impedance of the pulse power source and the discharge electrode due to the change in impedance during the streamer discharge is matched by matching the characteristic impedance of the pulse power source with the impedance between the electrodes. Inconsistencies can be resolved.
  • the discharge is terminated within 1.5 times the streamer discharge time (streamer development time). Typically, the discharge is performed only with the streamer discharge, thereby reducing the heat loss during the glow-like discharge. Can be reduced or eliminated.
  • Pulse generator A schematic view of a pulse generator is shown in FIG. 1A.
  • the pulse generator consists of a high-intensity spark gap switch (SGS) 1 as a low-inductance, high-speed self-closing switch, a triaxial Blumlein line 2 as a pulse forming line, and a Bloomline-type line. And an energy transmission line (Transmission Line) 3 to a load.
  • SGS1 has a gap spacing of 1 mm and is filled with SF 6 insulating gas. The magnitude of the output voltage from the pulse generator can be adjusted by changing the SF 6 pressure.
  • the triaxial bloom line type line 2 is composed of a rod-shaped inner conductor 20, a cylindrical intermediate conductor 21, and a cylindrical outer conductor 22.
  • the conductors are made of brass and are arranged concentrically.
  • the triaxial bloom line type line 2 and the energy transmission line 3 are filled with transformer oil (Transformer Oil) as an insulating medium.
  • Transformer Oil Transformer Oil
  • the inner conductor and the outer conductor are connected via a charging inductor 4 and the outer conductor is grounded.
  • the intermediate conductor is charged through a charging port 5 by a pulse forming circuit including a charging capacitor, a thyratron switch (CX1685, E2V Technologies, Ltd., UK), and a pulse transformer.
  • the unit inductance and unit capacitance of the 3-axis bloom line type line are 322 nH / m and 76 pF / m, respectively, and give a characteristic impedance of 130 ⁇ (however, the embodiment of the pulse discharge device according to the present invention) Then, the pulse power supply is manufactured so that the characteristic impedance value matches the impedance value of the discharge electrode.)
  • the length of the Bloom line type line is 500 mm, and a pulse with a duration of 5 ns is given.
  • the triaxial bloom line type line is charged with a negative pulse voltage and the positive electrode is applied to the load.
  • a coaxial transmission line having a characteristic impedance of 130 ⁇ is used as the energy transmission line from the Bloom line type line to the load.
  • the output voltage of the pulse generator is measured by providing a capacitive voltage divider on the transmission line.
  • the output current of the pulse generator is measured by a current transformer (Pearson Current Monitor Model 6658, Pearson Electronics, USA) installed at the end of the transmission line.
  • the pulse voltage output from the pulse generator is applied between a pair of electrodes arranged in the discharge reactor.
  • an electrode arranged coaxially from the internal electrode and the external electrode is used.
  • the shape and dimensions of the electrode are not limited to those described in this specification.
  • FIG. 2 shows the state of pulse discharge in a coaxial cylindrical electrode filled with dry air having an inner electrode outer diameter of 0.5 mm, an outer electrode inner diameter of 76 mm, and an electrode length of 10 mm.
  • the maximum peak value of the positive polarity applied pulse voltage to the electrode is +72 kV, its rise and fall times are 50 ns, and its duration (half width) is 100 ns.
  • a streamer head (a group of positive ions formed due to electron avalanche and high electron mobility after application of a pulse voltage, has a high spatial electric field, and emits light due to ionization, dissociation, recombination, and the like.
  • a plasma channel is formed on the back by positive ions and avalanche electrons) in the vicinity of the positive internal line electrode (10-15 ns), and then progresses toward the grounded external cylindrical electrode It is confirmed that the ground electrode is reached (50-55ns).
  • the phase of the pulse discharge changes dramatically from the streamer discharge (the progress between the electrodes of the streamer head), and the glow-like discharge across the electrodes (in the plasma channel formed by the streamer head).
  • the current density at the center of the electrode increases due to the electrode structure, and light is emitted strongly.
  • the discharge ends with the fall of the pulse voltage.
  • the electric field near the internal line electrode that has been relaxed by the streamer head gradually recovers with the progress of the streamer head between the electrodes. As a result, the streamer head is formed again (30-35ns). Progress towards external cylindrical electrodes (up to 50-55ns) is also confirmed.
  • FIG. 2 confirms that the pulse discharge is composed of two discharge modes, a streamer discharge and a glow-like discharge.
  • FIG. 3 shows a streak image of pulse discharge imaged under the same conditions as the framing image of FIG.
  • the upper and lower ends coincide with the grounded outer electrode inner surface and the positive inner electrode outer surface of the coaxial cylindrical electrode, and the horizontal axis indicates the elapsed time.
  • the formation time of the streamer head in the vicinity of the positive internal line electrode is set to 0 ns.
  • FIG. 4 shows the dependency of the streamer head progress rate on the applied voltage to the positive internal line electrode when three pulse voltages having different peak values are applied to the same coaxial cylindrical electrode as in the framing imaging of FIG. From Fig. 4, at three different peak values, the streamer head progress rate during the streamer discharge period has the same dependency on the applied voltage to the internal line electrode, the applied voltage to the internal electrode increases, and the streamer head progress rate. Is confirmed to increase. It is also confirmed that the streamer head progress rate is 0.1-1.8 mm / ns at an applied voltage of 10-60 mmkV.
  • FIG. 5 shows a typical applied voltage and discharge current waveform to the electrode during the pulse discharge shown in FIGS. From FIG. 5, as described in [B-1], a positive pulse voltage (maximum peak value: +72 kV, rise and fall time: 50 ns, half-value time width: 100 ns) is applied between the electrodes. That is confirmed. As for the discharge current, it was confirmed that the current that was about 5 A during the streamer discharge period increased rapidly to about 40 A during the glow-like discharge period.
  • This total measured current is the sum of the displacement current to the coaxial cylindrical electrode and the discharge current.
  • the capacity of the coaxial cylindrical electrode changes with the progress of the streamer head, it is difficult to strictly separate the two currents.
  • the variation current to the coaxial cylindrical electrode is calculated as shown in FIG.
  • the discharge current is indicated by the difference between the total current and the mutation current, and it is confirmed that the discharge current increases with the progress of the streamer head and reaches a maximum of about 5A.
  • the increase in the discharge current is considered to be caused by the increase in the progress speed of the streamer head.
  • the average electron energy is considered to be about 1-2 eV.
  • FIG. 6 shows the interelectrode (pulse discharge plasma) impedance calculated from the voltage applied to the electrode shown in FIG. 5 and the discharge current.
  • the interelectrode impedance As described in [B-3], since the discharge mode shifts from the streamer discharge to the glow-like discharge and the current rapidly increases, it is confirmed that the interelectrode impedance also changes suddenly with the change of the discharge mode.
  • the interelectrode impedance during the glow-like discharge period is equivalent to the total impedance of all the plasma channels formed during the progress of the streamer head, and it is confirmed that the value is about 2 K ⁇ .
  • the difference in inter-electrode impedance during the streamer and glow-like discharge period causes impedance mismatch between the pulse power source and the discharge electrode.
  • FIG. 7 confirms that although the gas temperature does not change during the streamer discharge period, the gas temperature increases with the passage of time during the glow-like discharge period, and finally reaches about 450K. This is because during the glow-like discharge period, a large discharge current flows in the plasma channel formed by the streamer head, so that the current density increases and the positive ions in the channel are heated. This heating is an energy loss for the formation of non-thermal equilibrium plasma.
  • Table 1 summarizes various characteristics related to the above-described pulse discharge. From Table 1, it can be seen that, in pulse discharge, the transition from a discharge-like streamer to a glow-like discharge not only causes a mismatch between the pulse power supply and the discharge electrode, but also causes an energy loss of gas heating. It is confirmed.
  • the problems in conventional pulse discharge include (1) Impedance mismatch between pulse power supply and discharge electrode; (2) Heat loss during glow-like discharge; There is As the cause of (1), (A) Abrupt change in impedance between electrodes during transition from streamer discharge to glow-like discharge; (A) Change in impedance between electrodes during streamer discharge; There is.
  • the present invention provides a discharge generation method and apparatus using a so-called nanosecond pulse discharge in order to solve the problems in the conventional pulse discharge.
  • the nanosecond pulse discharge is a pulse discharge using a pulse voltage having a pulse rise time of 10 ns or less, and is typically a pulse discharge that does not shift to a glow-like discharge, that is, formed only by a streamer discharge. An embodiment of nanosecond pulse discharge will be described below.
  • FIG. 8 shows the state of nanosecond pulse discharge in the same coaxial cylindrical electrode as that of pulse discharge framing in FIG. Shows a framing image taken at. Note that the exposure time of the ICCD camera at the time of framing photography is constant 0.2 ns, and the photographing time is shown at the top of each photographed image with the formation time of the streamer head near the positive internal line electrode being Tns.
  • the maximum peak value of the positive polarity applied pulse voltage to the electrode was +100 kV, its rise and fall time was 2 ns, and its duration (half width) was 5 ns.
  • the streamer head is formed in the vicinity of the positive internal line electrode (Tns) after the pulse voltage is applied, and then progresses toward the grounded external cylindrical electrode. (T + 3ns) is confirmed.
  • the discharge phase does not shift to a glow-like discharge as the streamer head reaches the ground electrode, and the discharge ends with a fast fall of the pulse voltage.
  • the formation of the streamer head again (T + 1ns) and its progress toward the external cylindrical electrode (T + 2-3ns) are confirmed. That is, it is confirmed from FIG. 8 that the nanosecond pulse discharge is composed of only the streamer discharge.
  • FIG. 9 shows a streak image of nanosecond pulse discharge imaged under the same conditions as the framing image of FIG.
  • the upper end and the lower end coincide with the grounded outer electrode inner surface and the positive inner electrode outer surface of the coaxial cylindrical electrode, as in FIG. 3, and the horizontal axis indicates the elapsed time.
  • the formation time of the streamer head near the positive internal line electrode is set to 0 ns.
  • FIG. 9 confirms the state of nanosecond pulse discharge similar to that described in [C-1]. Further, it is confirmed that the streamer head advances between the electrodes at a substantially constant speed during the streamer discharge period.
  • FIG. 10 shows the relationship between the position of the streamer head in the framing shot image of FIG. 8 and each shooting time.
  • FIG. 10 also confirms that the streamer head progresses at a constant speed in the nanosecond pulse discharge, as in FIG.
  • the progress rate is 8.8 mm / ns, which is about 5 times the progress rate in pulse discharge. This is because a high voltage of 100 kV could be applied between the electrodes because the rise of the pulse voltage was nanoseconds.
  • FIG. 10 shows the relationship between the position of the streamer head in the framing shot image of FIG. 8 and each shooting time.
  • FIG. 10 also confirms that the streamer head progresses at a constant speed in the nanosecond pulse discharge, as in FIG.
  • the progress rate is 8.8 mm / ns, which is
  • FIG. 11 shows the electrode impedance (A) when nanosecond pulse discharge is formed in coaxial cylindrical electrodes (inner electrode outer diameter 0.5 mm, outer electrode inner diameter 76 mm) having electrode lengths of 200 mm and 800 mm, and used for calculation thereof.
  • An applied voltage / current waveform to an electrode (B: electrode length 200 mm, C: 800 mm) is shown.
  • FIG. 11A confirms that the electrode impedance is constant at about 0.3 k ⁇ in nanosecond pulse discharge.
  • the nanosecond pulse discharge is a mismatch between the pulse power source and the discharge electrode, which was a factor of low energy efficiency during non-thermal equilibrium plasma formation by pulse discharge (in the above example, the pulse power source whose characteristic impedance is 0.3 k ⁇ ) This makes it possible to match both the impedance and the heat loss during glow-like discharge.
  • FIG. 12 shows NO treatment results by pulse discharge plasma and nanosecond pulse discharge plasma.
  • the simulated exhaust gas was composed of N 2 Balance / NO 200 ppm / O 2 5% / H 2 O 2%, flow rate 2.0 L / min, inner electrode outer diameter 0.5 mm, outer electrode inner diameter 76 mm, electrode length 500 mm. It flows to the coaxial cylindrical electrode (800 mm in the case of nanosecond pulse discharge treatment), and between the electrodes by a general pulse power supply (time width: 40-120 ns) and nanosecond pulse power supply (time width: 5 ns) This was done by forming a non-thermal equilibrium plasma.
  • the vertical axis in FIG. 12 is the NO treatment energy efficiency relative to the energy injected into the electrode, and the horizontal axis is the NO removal rate. Therefore, it means that the removal capability and the removal energy efficiency are excellent in the upper right of the graph.
  • the NO removal energy efficiency decreases as the NO removal rate increases in all pulse time widths. This is because with the progress of NO removal, the reaction rate between NO and chemically active species that are responsible for NO treatment decreases. Further, it is confirmed that the NO removal energy efficiency is improved with the decrease of the pulse time width at the same NO removal rate.
  • the improvement in NO removal energy efficiency accompanying the shortening of the pulse time width from 120 ns to 40 ns is due to the reduction of heat loss due to the shortening of the glow-like discharge time in the pulse discharge, which is caused by the nanosecond pulse discharge.
  • the improvement in NO removal energy efficiency is considered to be due to the fact that there is no heat loss due to glow-like discharge and the improvement in the generation efficiency of chemically active species accompanying the increase in applied voltage.
  • FIG. 13 shows a characteristic map of an air source ozonizer by nanosecond pulse discharge plasma and other electrical discharge plasma.
  • the vertical axis represents the ozone generation energy efficiency relative to the energy injected into the electrode
  • the horizontal axis represents the ozone generation concentration. The higher the position on the upper right of the map, the better the ozonizer.
  • the ozone generation conditions by the nanosecond pulse discharge plasma are as follows: the raw material dry air flow rate is 1.0 L / min, the parameters of the coaxial cylindrical electrode are the inner electrode outer diameter 0.5 mm, the outer electrode inner diameter 76 mm, and the electrode length 200 mm.
  • FIG. 14 shows an output waveform (load: 100 ⁇ , polarity: negative) of the 0.5 ns power supply.
  • the experimental conditions are the same as those in paragraph 0025 except for the length of the bloom line type line.
  • the length of the bloom line type line in the experimental apparatus is 50 mm.
  • 0.05 to 0.20 MPa indicates the pressure in the gap switch, and the output voltage is controlled by this pressure. It can be seen from FIG. 14 that the voltage rise is 0.5 ns, the voltage fall is 0.5 ns, and the voltage duration is 1 ns (half-value width).
  • the discharge method and apparatus according to the present invention can be used for industrial exhaust gas purification, ozone generation, combustion gas reforming, combustion state improvement, and combustion exhaust gas purification.
  • FIG. 1 It is a figure which shows the streak image of nanosecond pulse discharge. It is a figure which shows the time dependence of the streamer head position in nanosecond pulse discharge.
  • A is a figure which shows the impedance waveform between electrodes at the time of the streamer discharge in nanosecond pulse discharge (electrode length is 200 mm, 800 mm).
  • B is a figure which shows the applied voltage and discharge current waveform (electrode length 200mm) at the time of nanosecond pulse discharge.
  • (C) is a figure which shows the applied voltage and discharge current waveform (electrode length 800mm) at the time of nanosecond pulse discharge. It is a figure which shows the NO process result by pulse discharge plasma. It is a figure which shows the characteristic map of the air raw material ozonizer by discharge plasma. The output waveform by other subnanosecond pulse power supplies is shown.

Abstract

This invention provides a pulse discharge that achieves a high energy efficiency. A pair of electrodes are prepared together with a pulse power supply that generates pulses having a rising time of 10 ns or less. A pulse voltage having a rising time of 10 ns or less is applied between the electrodes, thereby causing a streamer head to develop from one of the electrodes to the other at a constant speed. A duration of the pulses and a value of the applied voltage are selected in accordance with the distance between the electrodes, thereby causing the discharge to terminate when the developing streamer head reaches the other electrode.

Description

パルス放電発生方法及び装置Pulse discharge generation method and apparatus
本発明は、放電発生方法及び装置に関するものである。 The present invention relates to a discharge generation method and apparatus.
電子ビームや電気的放電により形成される非熱平衡プラズマは、その化学的活性度の高さから窒素酸化物（NOX）や硫黄酸化物（SOX）の処理といった燃焼排気ガスの浄化や揮発性有機化合物（VOCs）の処理といった産業排気ガスの浄化、次世代の酸化剤としての利用が期待されるオゾン（O3）の生成など、多岐にわたる応用展開が期待され、継続した研究がなされている。 Non-thermal equilibrium plasma formed by electron beam and electrical discharge is purified from combustion exhaust gas such as nitrogen oxide (NO X ) and sulfur oxide (SO X ) treatment and volatility due to its high chemical activity. A wide range of applications are expected, such as purification of industrial exhaust gases, such as treatment of organic compounds (VOCs), and generation of ozone (O 3 ), which is expected to be used as the next-generation oxidant. .
しかしながら、そのエネルギー効率の低さが大きな障壁となっており、未だその実用化例は多くはない。電気的放電による非熱平衡プラズマの形成においては、如何に放電を熱平衡プラズマの1種であるアーク放電（スパーク放電などとも呼ばれる）へ移行させないかがエネルギー効率改善に対する鍵のひとつである。その方法としては、金属電極間へ誘電体を挿入することにより受動的にアーク放電への移行を防ぐ誘電体バリア放電法（無性放電やオゾナイザー放電とも呼ばれる）と金属電極間へ印加する電圧波形により能動的にアーク放電への移行を防ぐパルス放電法が挙げられる。 However, the low energy efficiency is a big barrier, and there are not many practical examples. In the formation of non-thermal equilibrium plasma by electrical discharge, one of the keys to improving energy efficiency is how to prevent the discharge from being transferred to arc discharge (also called spark discharge) which is a kind of thermal equilibrium plasma. As a method for this, a dielectric barrier discharge method (also called asexual discharge or ozonizer discharge) that prevents passive transition to arc discharge by inserting a dielectric between metal electrodes and a voltage waveform applied between the metal electrodes The pulse discharge method that actively prevents the transition to arc discharge can be mentioned.
これまでの電気的放電により形成される非熱平衡プラズマに関する研究暦においては、複雑な回路構成を有し、かつ、高価なパルス電源に対して、既に完成された域にある交流電源を用いる誘電体バリア放電に関する研究が圧倒的多数であった。しかしながら、近年の半導体スイッチ及び磁性材料の特性改善によるパルス電源の特性向上は目覚ましいものがあり、パルス電源の信頼性及びエネルギー変換（プラグイン－パルス）効率を交流電源と遜色ないレベルまで押し上げつつある。 In the research calendar on non-thermal equilibrium plasmas formed by electrical discharges so far, a dielectric having a complicated circuit configuration and using an alternating current power source in an already completed area for an expensive pulse power source There were an overwhelming number of studies on barrier discharge. However, recent improvements in the characteristics of pulse power supplies due to improvements in the characteristics of semiconductor switches and magnetic materials are remarkable, and the reliability and energy conversion (plug-in-pulse) efficiency of pulse power supplies are being pushed to a level comparable to that of AC power supplies. .
しかしながら、以下に述べるように、従来のパルス放電は誘電体バリア放電に対してエネルギー変換効率が劣るものである。図1には誘電体バリア放電（上図）及びパルス放電による非熱平衡プラズマ形成システム（下図）のブロック図を示す。上図の誘電体バリア放電システムにおいては、交流電源から直接放電電極へエネルギーを注入するため、約85％と一般的な交流電源のエネルギー変換効率にてプラグインエネルギーを放電電極を介して非熱平衡プラズマへ注入することができる。 However, as described below, the conventional pulse discharge is inferior in energy conversion efficiency to the dielectric barrier discharge. Fig. 1 shows a block diagram of a non-thermal equilibrium plasma formation system (bottom) using dielectric barrier discharge (top) and pulse discharge. In the dielectric barrier discharge system shown above, energy is directly injected from the AC power source to the discharge electrode, so the plug-in energy is non-thermally balanced through the discharge electrode at approximately 85% and the energy conversion efficiency of a typical AC power source. It can be injected into the plasma.
一方、下図に示されるパルス放電システムでは、プラグインエネルギーを直流変換し、その後パルス変換して、更に放電電極を介して非熱平衡プラズマへ注入する。そのため、計32％ものプラグインエネルギーをそれぞれのエネルギー変換で消費することとなり、放電電極への注入エネルギーは最高でもプラグインエネルギーの68％程度となる。 On the other hand, in the pulse discharge system shown in the figure below, plug-in energy is converted into a direct current, then converted into a pulse, and further injected into non-thermal equilibrium plasma through a discharge electrode. Therefore, a total of 32% of plug-in energy is consumed by each energy conversion, and the maximum energy injected into the discharge electrode is about 68% of the plug-in energy.
また、パルス放電システムの場合には、直流及びパルス電源におけるエネルギー損失に加えて、パルス電源と放電電極（パルスプラズマ形成時）とのインピーダンス不整合によるエネルギー損失も存在し、現実的にパルス電源と放電電極とのインピーダンス整合は不可能であるため、実際の放電電極への注入エネルギーはプラグインエネルギーの30％程度となる。 In the case of the pulse discharge system, in addition to the energy loss in the direct current and the pulse power supply, there is also an energy loss due to impedance mismatch between the pulse power supply and the discharge electrode (when the pulse plasma is formed). Since impedance matching with the discharge electrode is impossible, the actual energy injected into the discharge electrode is about 30% of the plug-in energy.
これまでにパルス放電法による非熱平衡プラズマ形成に関する研究が少数であった要因は、パルス電源の複雑さもさることながら、このシステムとしての低エネルギー変換効率が最大であったと考えられる。 The reason for the few studies on non-thermal equilibrium plasma formation by the pulse discharge method so far is considered to be that the low energy conversion efficiency of this system is the maximum, in addition to the complexity of the pulse power supply.
本出願の発明者等は、いわゆるナノ秒パルス放電について研究を行なっており（非特許文献１、非特許文献２）、本発明は、ナノ秒パルス放電を用いることで、これまで低いエネルギー変換効率に留まらざるを得なかったパルス放電法を改善することを目的とする。
T. Namihira, D. Wang, S. Katsuki,R. Hackam and H. Akiyama, "Propagation velocity of pulsed streamer dischargesin atmospheric air", IEEE Transactions on Plasma Science, Vol.31, No.5,PP.1091-1094, 2003. T. Namihira, T. Tokuichi, D. Wang, S. Katsuki, H. Akiyama,"Characterization of nano-seconds pulsed streamer discharges", 2007 IEEE PulsedPower and Plasma Science Conference, Albuquerque, USA, pp.572-575, 2007. The inventors of the present application have been studying so-called nanosecond pulse discharge (Non-Patent Document 1 and Non-Patent Document 2), and the present invention uses a nanosecond pulse discharge, so far it has a low energy conversion efficiency. It aims at improving the pulse discharge method which had to stay in this.
T. Namihira, D. Wang, S. Katsuki, R. Hackam and H. Akiyama, "Propagation velocity of pulsed streamer dischargesin atmospheric air", IEEE Transactions on Plasma Science, Vol.31, No.5, PP.1091-1094 , 2003. T. Namihira, T. Tokuichi, D. Wang, S. Katsuki, H. Akiyama, "Characterization of nano-seconds pulsed streamer discharges", 2007 IEEE PulsedPower and Plasma Science Conference, Albuquerque, USA, pp.572-575, 2007 .
本発明は、高いエネルギー効率をもたらすパルス放電発生方法及び装置を提供することを目的とするものである。 It is an object of the present invention to provide a pulse discharge generation method and apparatus that provide high energy efficiency.
　本発明が採用した第１の技術手段は、
　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間が１０ns以下のパルスを生成するパルス電源と、を用意し、
　立ち上り時間が１０ns以下のパルス電圧を前記電極間に印加することで第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
　電極間距離に対応して、パルスの持続時間、印加電圧を選択することで、進展するストリーマヘッドが前記第２の電極に到達する時に放電を終了させる、
　パルス放電発生方法、
　あるいは、
　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間が１０ns以下のパルスを生成するパルス電源と、からなる放電発生装置であって、
　前記パルス電源は、立ち上り時間が１０ns以下のパルス電圧を前記電極間に印加することで第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
　パルスの持続時間、印加電圧は、電極間距離に対応して、進展するストリーマヘッドが前記第２の電極に到達する時に放電が終了するように選択されている、
　パルス放電発生装置、である。 The first technical means adopted by the present invention is:
Preparing a discharge electrode including a first electrode and a second electrode, and a pulse power source for generating a pulse having a rise time of 10 ns or less;
By applying a pulse voltage having a rise time of 10 ns or less between the electrodes, the streamer head is advanced from the first electrode to the second electrode at a constant speed,
Corresponding to the distance between the electrodes, by selecting the duration of the pulse, the applied voltage, the discharge is terminated when the developing streamer head reaches the second electrode,
Pulse discharge generation method,
Or
A discharge generator comprising: a discharge electrode comprising a first electrode and a second electrode; and a pulse power supply that generates a pulse having a rise time of 10 ns or less,
The pulse power source causes a streamer head to advance at a constant speed from the first electrode to the second electrode by applying a pulse voltage having a rise time of 10 ns or less between the electrodes,
The duration of the pulse, the applied voltage is selected such that the discharge ends when the evolving streamer head reaches the second electrode, corresponding to the distance between the electrodes,
A pulse discharge generator;
　本発明では、立ち上り時間が１０ns以下のパルス電圧を電極間に印加することで、ストリーマ放電（ストリーマヘッドの電極間進展）時にストリーマヘッドを等速で進展させ、これによって、ストリーマ放電時における電極間インピーダンス（放電時の「放電電極インピーダンス」、ないし「放電インピーダンス」）の値を一定にすることが可能となった。ストリーマ放電時における電極間インピーダンスの値を一定にすることによって、パルス電源の特性インピーダンスを電極間インピーダンスに一致させることで、ストリーマ放電時のインピーダンスの変化に起因するパルス電源と放電電極とのインピーダンスの不整合を解消することができる。
　本発明において、パルスの立ち上がり時間は１０ns以下（０は除く）のいかなる値（例えば、９ｎｓ，８ｎｓ，７ｎｓ，６ｎｓ，５ｎｓ，４ｎｓ，３ｎｓ，２ｎｓ，１ｎｓ，１ｎｓ未満（０は除く）、ないし、これらの間の任意の数値）を取り得る。パルスの立ち上がり時間が１０ｎｓよりも大きくなると、ストリーマ放電時のインピーダンス変化という不具合が生じる。本発明においてパルスの立ち上がり時間はより短い方が望ましく、１つの態様では、パルスの立ち上がり時間は９ｎｓ以下であり、１つの態様では８ｎｓ以下であり、１つの態様では７ｎｓ以下であり、１つの態様では６ｎｓ以下であり、１つの態様では５ｎｓ以下であり、１つの態様では４ｎｓ以下であり、１つの態様では３ｎｓ以下であり、１つの態様では２ｎｓ以下であり、1つの態様では１ｎｓ以下である。 In the present invention, by applying a pulse voltage having a rise time of 10 ns or less between the electrodes, the streamer head is developed at a constant speed during streamer discharge (development between the electrodes of the streamer head). The impedance (“discharge electrode impedance” or “discharge impedance” during discharge) can be kept constant. By making the value of the impedance between the electrodes in the streamer discharge constant, the impedance of the pulse power source and the discharge electrode due to the change in impedance during the streamer discharge is matched by matching the characteristic impedance of the pulse power source with the impedance between the electrodes. Inconsistencies can be resolved.
In the present invention, the rise time of the pulse is 10 ns or less (except 0) (for example, 9 ns, 8 ns, 7 ns, 6 ns, 5 ns, 4 ns, 3 ns, 2 ns, 1 ns, less than 1 ns (excluding 0), or Any numerical value between them can be taken. When the rise time of the pulse is longer than 10 ns, there arises a problem of impedance change during streamer discharge. In the present invention, it is desirable that the pulse rise time is shorter. In one embodiment, the pulse rise time is 9 ns or less, in one embodiment, 8 ns or less, and in one embodiment, 7 ns or less. 6 ns or less, one embodiment 5 ns or less, one embodiment 4 ns or less, one embodiment 3 ns or less, one embodiment 2 ns or less, and one embodiment 1 ns or less. .
　本発明が採用した第２の技術手段は、
　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間が１０ns以下のパルスを生成するパルス電源と、を用意し、
　立ち上り時間が１０ns以下のパルス電圧を電極間に印加してストリーマ放電を生成して、第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
　電極間距離に対応して、パルスの持続時間、印加電圧を選択することで、ストリーマ放電の時間の１．５倍の時間内に放電を終了させる、
　パルス放電発生方法、
　あるいは、
　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間が１０ns以下のパルスを生成するパルス電源と、からなる放電発生装置であって、
　前記パルス電源は、立ち上り時間が１０ns以下のパルス電圧を電極間に印加してストリーマ放電を生成して、第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
　パルスの持続時間、印加電圧は、電極間距離に対応して、ストリーマ放電の時間の１．５倍の時間内に放電が終了するように選択されている、
　パルス放電発生装置、である。 The second technical means adopted by the present invention is:
Preparing a discharge electrode including a first electrode and a second electrode, and a pulse power source for generating a pulse having a rise time of 10 ns or less;
Applying a pulse voltage having a rise time of 10 ns or less between the electrodes to generate a streamer discharge, and causing the streamer head to advance at a constant speed from the first electrode to the second electrode;
By selecting the duration of the pulse and the applied voltage according to the distance between the electrodes, the discharge is terminated within 1.5 times the streamer discharge time.
Pulse discharge generation method,
Or
A discharge generator comprising: a discharge electrode comprising a first electrode and a second electrode; and a pulse power supply that generates a pulse having a rise time of 10 ns or less,
The pulse power supply generates a streamer discharge by applying a pulse voltage having a rise time of 10 ns or less between the electrodes, and advances the streamer head from the first electrode to the second electrode at a constant speed.
The duration of the pulse and the applied voltage are selected to finish the discharge within 1.5 times the streamer discharge time, corresponding to the distance between the electrodes.
A pulse discharge generator;
　本発明では、電極間距離に対応して、パルスの持続時間、印加電圧を選択することで、ストリーマ放電の時間（ストリーマの進展時間）の１．５倍の時間内に放電を終了させることで、グロー様放電の時間を少なくすることができ、これによって、グロー様放電時の熱損失を低減することが可能となった。
　放電時間がストリーマ放電の時間（ストリーマの進展時間）の１．５倍を越えると、グロー様放電の時間が長くなり、熱損失がかなりのレベルに達する。本発明において、ストリーマ放電の時間（ストリーマの進展時間）の１．５倍の時間内には、１．５倍以下のいかなる数値の倍数（例えば、１．４倍以下、１．３倍以下、１．２倍以下、１．１倍以下）が含まれる。グロー様放電時の熱損失を可及的に小さくするためには、この倍数はより少ない方が望ましい。また、本発明において、この倍数は１未満であってもよい（すなわち、ストリーマヘッドが第２の電極に到達する前に放電を終了させてもよい）。
　１つの望ましい態様では、進展するストリーマヘッドが前記第２の電極に到達する時に放電を終了させる（すなわち、ストリーマの進展時間の１倍）ことで、放電をストリーマ放電のみで行なう。放電をストリーマ放電でのみで行なうことで、パルス電源の特性インピーダンスをストリーマ放電時の電極間インピーダンスに一致させるだけでよく、ストリーマ放電からグロー様放電への移行時のインピーダンスの急変に起因するパルス電源と放電電極とのインピーダンスの不整合を解消することができる。放電をストリーマ放電でのみで行なうことで、グロー様放電時の熱損失を可及的に小さくする、あるいは無くすことができる。 In the present invention, by selecting the duration of the pulse and the applied voltage according to the distance between the electrodes, the discharge is terminated within 1.5 times the streamer discharge time (streamer progress time). The time for glow-like discharge can be reduced, which makes it possible to reduce heat loss during glow-like discharge.
When the discharge time exceeds 1.5 times the streamer discharge time (streamer progress time), the glow-like discharge time becomes longer and the heat loss reaches a considerable level. In the present invention, within a time 1.5 times the streamer discharge time (streamer progress time), a multiple of any numerical value of 1.5 times or less (for example, 1.4 times or less, 1.3 times or less, 1.2 times or less, 1.1 times or less). In order to minimize the heat loss during glow-like discharge, it is desirable that this multiple is smaller. In the present invention, this multiple may be less than 1 (that is, the discharge may be terminated before the streamer head reaches the second electrode).
In one desirable mode, the discharge is terminated only by the streamer discharge by terminating the discharge when the progressing streamer head reaches the second electrode (that is, one time the progress time of the streamer). By performing discharge only with streamer discharge, it is only necessary to match the characteristic impedance of the pulse power supply with the inter-electrode impedance during streamer discharge, and pulse power supply caused by a sudden change in impedance during the transition from streamer discharge to glow-like discharge. And the impedance mismatch between the discharge electrodes can be eliminated. By performing the discharge only with the streamer discharge, the heat loss during the glow-like discharge can be minimized or eliminated.
　本発明が採用した第３の技術手段は、
　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間がストリーマヘッド形成時間より短いパルスを生成するパルス電源と、を備え、
　前記パルス電源からパルス電圧を前記電極間に印加することで第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
　電極間距離に対応して、パルスの持続時間、印加電圧を選択することで、進展するストリーマヘッドが前記第２の電極に到達する時に放電を終了させる、
　パルス放電発生方法及び装置、
　あるいは、
　　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間がストリーマヘッド形成時間より短いパルスを生成するパルス電源と、を備え、
　前記パルス電源からパルス電圧を電極間に印加してストリーマ放電を生成して、第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
　電極間距離に対応して、パルスの持続時間、印加電圧を選択することで、ストリーマ放電の時間の１．５倍の時間内に放電を終了させる、
　パルス放電発生方法及び装置、である。 The third technical means adopted by the present invention is:
A discharge electrode including a first electrode and a second electrode, and a pulse power source that generates a pulse whose rise time is shorter than the streamer head formation time,
By applying a pulse voltage from the pulse power source between the electrodes, a streamer head is developed at a constant speed from the first electrode to the second electrode,
Corresponding to the distance between the electrodes, by selecting the duration of the pulse, the applied voltage, the discharge is terminated when the developing streamer head reaches the second electrode,
Pulse discharge generation method and apparatus,
Or
A discharge electrode including a first electrode and a second electrode, and a pulse power source that generates a pulse whose rise time is shorter than the streamer head formation time,
A pulse voltage is applied between the electrodes from the pulse power source to generate a streamer discharge, and a streamer head is developed at a constant speed from the first electrode to the second electrode,
By selecting the duration of the pulse and the applied voltage according to the distance between the electrodes, the discharge is terminated within 1.5 times the streamer discharge time.
A pulse discharge generation method and apparatus.
　ストリーマ放電時間は、「ストリーマヘッドの形成時間」＋「ストリーマヘッドの電極間進展時間」であり、従来の一般的なパルス放電（例えば、電圧立ち上がり時間４０ｎｓ）の電圧立ち上がり時間はストリーマヘッド形成時間より長いため、ストリーマヘッドの電極間進展中に電圧が増加することとなり、結果としてストリーマヘッドの進展速度が変化する。これに対して、ナノ秒パルス放電（電圧立ち上がり時間が１０ｎｓ以下、例えば、電圧立ち上がり時間２ｎｓ）の電圧立ち上がり時間はストリーマヘッド形成時間より短いため、ストリーマヘッドの電極間進展が始まる前に電圧が立ちあがり、ストリーマが進展しえいるときに電極への印加電圧がほぼ一定となって、結果としてストリーマヘッドが等速運動することとなる。 The streamer discharge time is “streamer head formation time” + “streamer head interelectrode progress time”, and the voltage rise time of a conventional general pulse discharge (for example, voltage rise time 40 ns) is greater than the streamer head formation time. Since it is long, the voltage increases during the progress of the streamer head between the electrodes, and as a result, the progress speed of the streamer head changes. On the other hand, since the voltage rise time of nanosecond pulse discharge (voltage rise time is 10 ns or less, for example, voltage rise time 2 ns) is shorter than the streamer head formation time, the voltage rises before the streamer head progresses between the electrodes. When the streamer is progressing, the voltage applied to the electrodes becomes substantially constant, and as a result, the streamer head moves at a constant speed.
　本発明において、電極間距離に対応して、パルスの持続時間、印加電圧を選択することで、放電時間（放電の終了時）を決定することができる。ここで、「ストリーマの外部電極（第２の電極）への到達時間Ｔ」は「電極間の距離Ｌ」/「ストリーマの進展速度Ｓ」となり、放電をストリーマ放電でのみで行なう場合には、ストリーマが外部電極へ到達した直後に電圧をゼロにする、すなわち、「パルス持続時間Ｐ」はこのＴであることが望まれる。しかし、Ｓは印加電圧Ｖに依存する（Ｖが増加するとＳも増加する）ため、Ｐは固定値とはならない。尚、パルス立ち上がり及び立ち下がり速度については、速ければ速いほど放電終了時の決定の制御を乱す可能性が減少するものであり、概ね１０ｎｓ以下であれば問題ないと考えられる。パルスの立ち下がり時間についても、立ち上がり時間と同様に、１０ns以下（０は除く）のいかなる値（例えば、９ｎｓ，８ｎｓ，７ｎｓ，６ｎｓ，５ｎｓ，４ｎｓ，３ｎｓ，２ｎｓ，１ｎｓ，１ｎｓ未満（０は除く）、ないし、これらの間の任意の数値）を取り得る。 In the present invention, the discharge time (at the end of discharge) can be determined by selecting the pulse duration and the applied voltage according to the distance between the electrodes. Here, the “arrival time T of the streamer to the external electrode (second electrode)” is “the distance L between the electrodes” / “the progress rate S of the streamer”, and when the discharge is performed only by the streamer discharge, It is desirable that the voltage be zeroed immediately after the streamer reaches the external electrode, ie, the “pulse duration P” is this T. However, since S depends on the applied voltage V (S increases as V increases), P is not a fixed value. As for the pulse rise and fall rates, the faster the rate, the less likely it will be that the control of determination at the end of the discharge is disturbed. Similarly to the rise time, the pulse fall time is less than 10 ns (excluding 0) (for example, less than 9 ns, 8 ns, 7 ns, 6 ns, 5 ns, 4 ns, 3 ns, 2 ns, 1 ns, and 1 ns (0 is Excluding) or any numerical value between them.
　本発明において、対となって放電電極を構成する第１の電極と第２の電極は、それぞれ１つ又は複数の電極から構成される。
　１つの態様では、前記対となって放電電極を構成する第１の電極と第２の電極は、同心状の外側の円筒状の電極と内側の円筒状ないし線状の電極とからなる。本発明に適用できる電極の構成については限定されず、線対平板、多線対平板、針対平板、多針対平板、ないし、当業者に知られているその他の形状や配置態様が含まれる。 In the present invention, the first electrode and the second electrode constituting the discharge electrode as a pair are each composed of one or a plurality of electrodes.
In one aspect, the first electrode and the second electrode constituting the discharge electrode as a pair include a concentric outer cylindrical electrode and an inner cylindrical or linear electrode. The electrode configuration applicable to the present invention is not limited, and includes wire-to-flat plate, multi-wire paired plate, needle-to-plate, multi-needle to flat plate, and other shapes and arrangements known to those skilled in the art. .
　１つの態様では、本発明は、上記パルス放電発生方法を用いて、前記電極間に供給した被処理ガスを処理する、ガス処理方法、あるいは、上記パルス放電発生装置を用いて、前記電極間に供給した被処理ガスを処理するように構成されている、ガス処理装置、として提供される。被処理ガスは、典型的には燃焼排ガス等の排ガスであり、であり、具体的には窒素酸化物（NOX）や硫黄酸化物（SOX）の処理が例示される。 In one aspect, the present invention provides a gas processing method for processing a gas to be processed supplied between the electrodes using the pulse discharge generation method, or a method for generating a gap between the electrodes using the pulse discharge generator. Provided as a gas processing apparatus configured to process a supplied gas to be processed. The gas to be treated is typically an exhaust gas such as a combustion exhaust gas. Specifically, the treatment of nitrogen oxide (NO x ) or sulfur oxide (SO x ) is exemplified.
　１つの態様では、本発明は、上記パルス放電発生方法を用いて、前記電極間に供給した酸素あるいは空気からオゾンを生成する、オゾン生成方法、あるいは、上記パルス放電発生装置を用いて、前記電極間に供給した酸素あるいは空気からオゾンを生成するように構成されている、オゾン生成装置、として提供される。 In one aspect, the present invention provides an ozone generation method for generating ozone from oxygen or air supplied between the electrodes using the pulse discharge generation method, or the electrode using the pulse discharge generation device. The present invention is provided as an ozone generator configured to generate ozone from oxygen or air supplied therebetween.
ストリーマ放電時における電極間インピーダンスの値を一定にすることによって、パルス電源の特性インピーダンスを電極間インピーダンスに一致させることで、ストリーマ放電時のインピーダンスの変化に起因するパルス電源と放電電極とのインピーダンスの不整合を解消することができる。放電をストリーマ放電でのみで行なうことで、ストリーマ放電からグロー様放電への移行時のインピーダンスの急変に起因するパルス電源と放電電極とのインピーダンスの不整合を解消することができる。したがって、パルス電源から放電反応器へのエネルギー転送効率を向上させることができる。 By making the value of the impedance between the electrodes in the streamer discharge constant, the impedance of the pulse power source and the discharge electrode due to the change in impedance during the streamer discharge is matched by matching the characteristic impedance of the pulse power source with the impedance between the electrodes. Inconsistencies can be resolved. By performing the discharge only with the streamer discharge, it is possible to eliminate the impedance mismatch between the pulse power source and the discharge electrode due to the sudden change of the impedance at the time of the transition from the streamer discharge to the glow-like discharge. Therefore, the energy transfer efficiency from the pulse power source to the discharge reactor can be improved.
ストリーマ放電の時間（ストリーマの進展時間）の１．５倍の時間内に放電を終了させる、典型的には、放電をストリーマ放電でのみで行なうことで、グロー様放電時の熱損失を可及的に小さくする、あるいは無くすことができる。 The discharge is terminated within 1.5 times the streamer discharge time (streamer development time). Typically, the discharge is performed only with the streamer discharge, thereby reducing the heat loss during the glow-like discharge. Can be reduced or eliminated.
[Ａ]パルス発生装置
パルス発生装置の概略図を図１Ａに示す。パルス発生装置は、低インダクタンスで高速自己閉鎖型のスイッチとしての高圧スパークギャップスイッチ（SGS）１と、パルスフォーミングラインとしての３軸ブルームライン型線路（Triaxial Blumlein Line）２と、ブルームライン型線路から負荷(Load)へのエネルギー伝送線路(Transmission Line)３と、を備えている。SGS１は１mmのギャップ間隔を備え、SF6絶縁ガスが充填されている。パルス発生装置からの出力電圧の大きさは、SF6の圧力を変化させることで調整可能である。 [A] Pulse generator A schematic view of a pulse generator is shown in FIG. 1A. The pulse generator consists of a high-intensity spark gap switch (SGS) 1 as a low-inductance, high-speed self-closing switch, a triaxial Blumlein line 2 as a pulse forming line, and a Bloomline-type line. And an energy transmission line (Transmission Line) 3 to a load. SGS1 has a gap spacing of 1 mm and is filled with SF 6 insulating gas. The magnitude of the output voltage from the pulse generator can be adjusted by changing the SF 6 pressure.
3軸ブルームライン型線路２は、ロッド状の内方導体(Inner Conductor)２０と、円筒状の中間導体(Middle Conductor)２１と、円筒状の外方導体（Outer Conductor）２２とからなり、これらの導体は真鍮から形成されており、同心状に配置されている。3軸ブルームライン型線路２、エネルギー伝送線路３は、絶縁媒体としてのトランスフォーマオイル(Transformer Oil)で充填されている。内方導体と外方導体は、充電用インダクタ(Charging Inductor)４を介して連結されており、外方導体は接地されている。中間導体は、充電キャパシタ、サイラトロンスイッチ（CX1685, E2V Technologies, Ltd., UK）、パルス変圧器からなるパルスフォーミング回路によって、充電ポート(Charging Port)５を介して充電される。 The triaxial bloom line type line 2 is composed of a rod-shaped inner conductor 20, a cylindrical intermediate conductor 21, and a cylindrical outer conductor 22. The conductors are made of brass and are arranged concentrically. The triaxial bloom line type line 2 and the energy transmission line 3 are filled with transformer oil (Transformer Oil) as an insulating medium. The inner conductor and the outer conductor are connected via a charging inductor 4 and the outer conductor is grounded. The intermediate conductor is charged through a charging port 5 by a pulse forming circuit including a charging capacitor, a thyratron switch (CX1685, E2V Technologies, Ltd., UK), and a pulse transformer.
試作した一例では、3軸ブルームライン型線路のユニットインダクタンス、ユニットキャパシタンスは、それぞれ、322nH/m、76pF/mであり、130Ωの特性インピーダンスを与える（但し、本発明に係るパルス放電装置の実施形態では、特性インピーダンスの値が、放電電極のインピーダンスの値と一致するようにパルス電源を製作する。）ブルームライン型線路の長さは500mmであり、５nsの持続時間のパルスを与える。１つの態様では、3軸ブルームライン型線路は負のパルス電圧が充電され、正極が負荷に与えられる。ブルームライン型線路から負荷へのエネルギー伝送線路としては、130Ωの特性インピーダンスを備えた同軸伝送線路が用いられる。尚、負荷に負極を与えるようにパルス発生装置を構成してもよい。 In the prototype, the unit inductance and unit capacitance of the 3-axis bloom line type line are 322 nH / m and 76 pF / m, respectively, and give a characteristic impedance of 130Ω (however, the embodiment of the pulse discharge device according to the present invention) Then, the pulse power supply is manufactured so that the characteristic impedance value matches the impedance value of the discharge electrode.) The length of the Bloom line type line is 500 mm, and a pulse with a duration of 5 ns is given. In one aspect, the triaxial bloom line type line is charged with a negative pulse voltage and the positive electrode is applied to the load. A coaxial transmission line having a characteristic impedance of 130Ω is used as the energy transmission line from the Bloom line type line to the load. In addition, you may comprise a pulse generator so that a negative electrode may be given to load.
容量性の電圧分圧器を伝送線路に設けることで、パルス発生装置の出力電圧を測定する。パルス発生装置の出力電流は、伝送線路の端部に設けた電流変圧器（Pearson Current Monitor Model 6585, Pearson Electronics, USA）によって測定する。 The output voltage of the pulse generator is measured by providing a capacitive voltage divider on the transmission line. The output current of the pulse generator is measured by a current transformer (Pearson Current Monitor Model 6658, Pearson Electronics, USA) installed at the end of the transmission line.
パルス発生装置から出力されたパルス電圧は、放電反応器内に配置された一対の電極間に印加される。本発明の実施形態では、内部電極と外部電極とから同軸状に配置された電極を用いているが、電極の形状や寸法は本明細書に記載のものに限定されないことは当業者に理解される。 The pulse voltage output from the pulse generator is applied between a pair of electrodes arranged in the discharge reactor. In the embodiment of the present invention, an electrode arranged coaxially from the internal electrode and the external electrode is used. However, it is understood by those skilled in the art that the shape and dimensions of the electrode are not limited to those described in this specification. The
［Ｂ］一般的なパルス放電
本発明に係るナノ秒パルス放電の前提となるパルス放電の基本的概念の説明及び本発明に係るナノ秒パルス放電との比較を目的として、一般的なパルス放電の特性について説明する。 [B] General Pulse Discharge For the purpose of explaining the basic concept of pulse discharge, which is the premise of the nanosecond pulse discharge according to the present invention, and for comparison with the nanosecond pulse discharge according to the present invention, The characteristics will be described.
［Ｂ－１］パルス放電のフレーミング撮影像
図2には、内部電極外径0.5mm、外部電極内径76mm、電極長10mmの乾燥空気で満たされた同軸円筒電極中におけるパルス放電の様子を電極軸方向から高速ゲート付ICCDカメラにて撮影したフレーミング像を示す。なお、フレーミング撮影時のICCDカメラの露光時間は5ns一定であり、撮影時間は電極への正極性パルス電圧印加時刻を0nsとして、各撮影像の右上に示している。また、電極への正極性印加パルス電圧の最大波高値は＋72kV、その立ち上がり及び立ち下がり時間は50ns、その持続時間（半値幅）は100nsである。 [B-1] Framing imaging image of pulse discharge FIG. 2 shows the state of pulse discharge in a coaxial cylindrical electrode filled with dry air having an inner electrode outer diameter of 0.5 mm, an outer electrode inner diameter of 76 mm, and an electrode length of 10 mm. A framing image taken with an ICCD camera with a high-speed gate from the direction. Note that the exposure time of the ICCD camera at the time of framing imaging is constant at 5 ns, and the imaging time is shown in the upper right of each captured image with the positive pulse voltage application time to the electrode being 0 ns. The maximum peak value of the positive polarity applied pulse voltage to the electrode is +72 kV, its rise and fall times are 50 ns, and its duration (half width) is 100 ns.
図2より、パルス電圧印加後、ストリーマヘッド（電子雪崩及び電子の高移動度のために形成される正イオン群であり、高い空間電界を有し電離、解離、再結合等による発光を伴う。また、進展とともにその背部へ正イオンと雪崩電子によるプラズマチャネルを形成する）が正極性内部線電極近傍へ形成され（10-15ns）、その後、接地された外部円筒電極へ向けて進展を開始し、接地極へ到達している（50-55ns）ことが確認される。 From FIG. 2, a streamer head (a group of positive ions formed due to electron avalanche and high electron mobility after application of a pulse voltage, has a high spatial electric field, and emits light due to ionization, dissociation, recombination, and the like. Along with the progress, a plasma channel is formed on the back by positive ions and avalanche electrons) in the vicinity of the positive internal line electrode (10-15 ns), and then progresses toward the grounded external cylindrical electrode It is confirmed that the ground electrode is reached (50-55ns).
このストリーマヘッドの接地極への到達とともに、パルス放電の様相はストリーマ放電（ストリーマヘッドの電極間進展）から劇的に変化して電極間全体におけるグロー様放電（ストリーマヘッドの形成したプラズマチャネル内での放電であり、電極構造により電極中心部の電流密度が大きくなり強く発光している）へと移行し、最終的にはパルス電圧の立ち下りとともに放電は終了する。また、ストリーマ放電期間において、ストリーマヘッドの電極間進展とともに、ストリーマヘッドにより緩和されていた内部線電極近傍の電界が徐々に回復するため、結果として再度ストリーマヘッドが形成され（30-35ns）、その外部円筒電極へ向けた進展（50-55nsまで）も確認される。 As the streamer head reaches the ground electrode, the phase of the pulse discharge changes dramatically from the streamer discharge (the progress between the electrodes of the streamer head), and the glow-like discharge across the electrodes (in the plasma channel formed by the streamer head). The current density at the center of the electrode increases due to the electrode structure, and light is emitted strongly. Finally, the discharge ends with the fall of the pulse voltage. In addition, during the streamer discharge period, the electric field near the internal line electrode that has been relaxed by the streamer head gradually recovers with the progress of the streamer head between the electrodes. As a result, the streamer head is formed again (30-35ns). Progress towards external cylindrical electrodes (up to 50-55ns) is also confirmed.
即ち、図2よりパルス放電はストリーマ放電とグロー様放電のふたつの放電様相にて構成されていることが確認される。 That is, FIG. 2 confirms that the pulse discharge is composed of two discharge modes, a streamer discharge and a glow-like discharge.
［Ｂ－２］パルス放電のストリーク撮影像
図3には、図2のフレーミング撮影と同一条件にて撮影したパルス放電のストリーク撮影像を示す。このストリーク撮影像において、上端及び下端は同軸円筒電極の接地された外部電極内表面及び正極性の内部電極外表面と一致しており、横軸は経過時間を示している。なお、経過時間においてはストリーマヘッドの正極性内部線電極近傍への形成時刻を0 nsとしている。 [B-2] Streak image of pulse discharge FIG. 3 shows a streak image of pulse discharge imaged under the same conditions as the framing image of FIG. In this streak image, the upper and lower ends coincide with the grounded outer electrode inner surface and the positive inner electrode outer surface of the coaxial cylindrical electrode, and the horizontal axis indicates the elapsed time. In the elapsed time, the formation time of the streamer head in the vicinity of the positive internal line electrode is set to 0 ns.
図3より、［Ｂ－１］の記述と同様のパルス放電の様子が確認される。また、ストリーマ放電期間においてストリーマヘッドが加速しながら電極間を進展していることが確認される。図4には、図2のフレーミング撮影と同一の同軸円筒電極へ3つの異なる波高値を有するパルス電圧を印加した場合のストリーマヘッド進展速度の正極性内部線電極への印加電圧依存性を示す。図4より、3つの異なる波高値において、ストリーマ放電期間におけるストリーマヘッド進展速度の内部線電極への印加電圧依存性は同様であり、内部電極への印加電圧が大きくなるとともに、ストリーマヘッドの進展速度が増加していることが確認される。また、ストリーマヘッドの進展速度は印加電圧10-60 kVにおいて0.1-1.8 mm/nsであることが確認される。 From FIG. 3, the state of pulse discharge similar to that described in [B-1] is confirmed. In addition, it is confirmed that the streamer head progresses between the electrodes while accelerating during the streamer discharge period. FIG. 4 shows the dependency of the streamer head progress rate on the applied voltage to the positive internal line electrode when three pulse voltages having different peak values are applied to the same coaxial cylindrical electrode as in the framing imaging of FIG. From Fig. 4, at three different peak values, the streamer head progress rate during the streamer discharge period has the same dependency on the applied voltage to the internal line electrode, the applied voltage to the internal electrode increases, and the streamer head progress rate. Is confirmed to increase. It is also confirmed that the streamer head progress rate is 0.1-1.8 mm / ns at an applied voltage of 10-60 mmkV.
［Ｂ－３］パルス放電中の印加電圧・電流波形
図5には、図2, 3に示されるパルス放電時の典型的な電極への印加電圧及び放電電流波形を示す。図5より、［Ｂ－１］でも述べているように、正極性のパルス電圧（最大波高値：＋72kV、立ち上がり及び立ち下がり時間：50ns、半値時間幅：100ns）が電極間へ印加されていることが確認される。また、放電電流については、ストリーマ放電期間においては5A程度であった電流が、グロー様放電期間においては40A程度まで急増していることが確認される。 [B-3] Applied Voltage / Current Waveform During Pulse Discharge FIG. 5 shows a typical applied voltage and discharge current waveform to the electrode during the pulse discharge shown in FIGS. From FIG. 5, as described in [B-1], a positive pulse voltage (maximum peak value: +72 kV, rise and fall time: 50 ns, half-value time width: 100 ns) is applied between the electrodes. That is confirmed. As for the discharge current, it was confirmed that the current that was about 5 A during the streamer discharge period increased rapidly to about 40 A during the glow-like discharge period.
先ず、ストリーマ放電期間における電流について考察する。この計測全電流は、同軸円筒電極への変位電流と放電電流の和であり、同軸円筒電極の容量がストリーマヘッドの進展とともに変化することを考慮すると、両電流の厳密な分離は困難である。しかしながら、ストリーマヘッドの電極に対する占有率が小さいため同軸円筒電極の容量がほぼ変化しないと仮定した場合、同軸円筒電極への変異電流は図5に示されるように算出される。このとき、放電電流は全電流と変異電流の差で示されることとなり、放電電流はストリーマヘッドの進展とともに増加し、最大で5A程度まで達していることが確認される。なお、この放電電流の増加は、ストリーマヘッドの進展速度増加に起因していると考えられる。 First, the current during the streamer discharge period will be considered. This total measured current is the sum of the displacement current to the coaxial cylindrical electrode and the discharge current. Considering that the capacity of the coaxial cylindrical electrode changes with the progress of the streamer head, it is difficult to strictly separate the two currents. However, assuming that the capacity of the coaxial cylindrical electrode does not substantially change because the occupation ratio of the streamer head to the electrode is small, the variation current to the coaxial cylindrical electrode is calculated as shown in FIG. At this time, the discharge current is indicated by the difference between the total current and the mutation current, and it is confirmed that the discharge current increases with the progress of the streamer head and reaches a maximum of about 5A. The increase in the discharge current is considered to be caused by the increase in the progress speed of the streamer head.
次に、グロー様放電期間における全電流は、ストリーマヘッドの進展時に形成されたプラズマチャネル内を流れるため、ストリーマヘッドの外部電極への到達、即ち、放電様相のストリーマ放電からグロー様放電への移行と同時に急増する。このときプラズマチャネル内は均一電界であると考えられ、その換算電界は約81Td（81×10-17Vcm2＝70 kV/3.6 cm/(2.4×1019個/cm3)）となり、チャネル内電子の平均エネルギーは1-2 eV程度と考えられる。 Next, since the total current in the glow-like discharge period flows in the plasma channel formed during the development of the streamer head, it reaches the external electrode of the streamer head, that is, transition from the discharge-like streamer discharge to the glow-like discharge. It increases rapidly at the same time. At this time, it is considered that the plasma channel has a uniform electric field, and the converted electric field is approximately 81 Td (81 × 10 -17 Vcm 2 = 70 kV / 3.6 cm / (2.4 × 10 19 cells / cm 3 )). The average electron energy is considered to be about 1-2 eV.
［Ｂ－４］パルス放電中の電極間インピーダンス
図6には、図5に示される電極への印加電圧及び放電電流より算出される電極間（パルス放電プラズマ）インピーダンスを示す。［Ｂ－３］にて記したように、放電様相がストリーマ放電からグロー様放電へ移行するとともに電流が急増するために、電極間インピーダンスもまた放電様相の移行とともに急変していることが確認される。 [B-4] Interelectrode Impedance During Pulse Discharge FIG. 6 shows the interelectrode (pulse discharge plasma) impedance calculated from the voltage applied to the electrode shown in FIG. 5 and the discharge current. As described in [B-3], since the discharge mode shifts from the streamer discharge to the glow-like discharge and the current rapidly increases, it is confirmed that the interelectrode impedance also changes suddenly with the change of the discharge mode. The
ストリーマ放電期間においては、時間経過とともに同軸円筒電極容量の充電が進むため、電極間インピーダンスが徐々に増加していることが確認される。 In the streamer discharge period, the charging of the coaxial cylindrical electrode capacitance proceeds with time, and it is confirmed that the interelectrode impedance gradually increases.
一方、グロー様放電期間における電極間インピーダンスは、ストリーマヘッドの進展時に形成された全プラズマチャネルの総インピーダンスと等価であり、その値は約2 kΩとなることが確認される。 On the other hand, the interelectrode impedance during the glow-like discharge period is equivalent to the total impedance of all the plasma channels formed during the progress of the streamer head, and it is confirmed that the value is about 2 KΩ.
このストリーマ及びグロー様放電期間における電極間インピーダンスの差異が、パルス電源と放電電極とのインピーダンス不整合の要因となる。 The difference in inter-electrode impedance during the streamer and glow-like discharge period causes impedance mismatch between the pulse power source and the discharge electrode.
［Ｂ－５］パルス放電中の電極内ガス温度
図7には、窒素分子の2nd　Positive　Bandからの放電発光スペクトルを理論スペクトルと比較・フィッティングすることで得られる正極性内部線電極近傍の窒素分子の回転温度（＝気体温度）の経時変化を示す。図7より、ストリーマ放電期間では気体温度の変化は見られないものの、グロー様放電期間では時間の経過とともに気体温度は上昇し、最終的には450K程度まで達していることが確認される。これは、グロー様放電期間においては、ストリーマヘッドが形成したプラズマチャネル内を大きな放電電流が流れるため、電流密度が大きくなりチャネル内の正イオンが加熱されたためである。なお、この加熱は非熱平衡プラズマの形成に対するエネルギー損失となる。 [B-5] Gas temperature in the electrode during pulse discharge FIG. 7 shows nitrogen molecules near the positive internal line electrode obtained by comparing and fitting the discharge emission spectrum from the second positive band of nitrogen molecules with the theoretical spectrum. Shows the change with time of the rotation temperature (= gas temperature). FIG. 7 confirms that although the gas temperature does not change during the streamer discharge period, the gas temperature increases with the passage of time during the glow-like discharge period, and finally reaches about 450K. This is because during the glow-like discharge period, a large discharge current flows in the plasma channel formed by the streamer head, so that the current density increases and the positive ions in the channel are heated. This heating is an energy loss for the formation of non-thermal equilibrium plasma.
［Ｂ－６］パルス放電に関するまとめ及び課題
表1には、上述のパルス放電に関する諸特性をまとめる。表1より、パルス放電において、放電様相のストリーマからグロー様放電への移行は、パルス電源と放電電極との不整合の要因となるばかりではなく、気体加熱というエネルギー損失をももたらしていることが確認される。
Figure JPOXMLDOC01-appb-T000001
 [B-6] Summary and problems related to pulse discharge Table 1 summarizes various characteristics related to the above-described pulse discharge. From Table 1, it can be seen that, in pulse discharge, the transition from a discharge-like streamer to a glow-like discharge not only causes a mismatch between the pulse power supply and the discharge electrode, but also causes an energy loss of gas heating. It is confirmed.
Figure JPOXMLDOC01-appb-T000001
より具体的には、従来のパルス放電における課題には、
（１）パルス電源と放電電極とのインピーダンスの不整合；
（２）グロー様放電時の熱損失；
があり、
（１）の原因としては、
（ア）ストリーマ放電からグロー様放電への移行時の電極間インピーダンスの急変；
（イ）ストリーマ放電時の電極間インピーダンスの変化；
がある。 More specifically, the problems in conventional pulse discharge include
(1) Impedance mismatch between pulse power supply and discharge electrode;
(2) Heat loss during glow-like discharge;
There is
As the cause of (1),
(A) Abrupt change in impedance between electrodes during transition from streamer discharge to glow-like discharge;
(A) Change in impedance between electrodes during streamer discharge;
There is.
［Ｃ］ナノ秒パルス放電
本発明は、上記従来のパルス放電における課題を解決するためにいわゆるナノ秒パルス放電を用いた放電発生方法及び装置を提供するものである。ナノ秒パルス放電は、パルスの立ち上がり時間が10ns以下のパルス電圧を用いたパルス放電であり、典型的には、グロー様放電へ移行しない、即ち、ストリーマ放電のみで形成されるパルス放電である。以下にナノ秒パルス放電の一実施形態について説明する。 [C] Nanosecond Pulse Discharge The present invention provides a discharge generation method and apparatus using a so-called nanosecond pulse discharge in order to solve the problems in the conventional pulse discharge. The nanosecond pulse discharge is a pulse discharge using a pulse voltage having a pulse rise time of 10 ns or less, and is typically a pulse discharge that does not shift to a glow-like discharge, that is, formed only by a streamer discharge. An embodiment of nanosecond pulse discharge will be described below.
［Ｃ－１］ナノ秒パルス放電のフレーミング撮影像
図8には、図2のパルス放電のフレーミング撮影と同一の同軸円筒電極中におけるナノ秒パルス放電の様子を電極軸方向から高速ゲート付ICCDカメラにて撮影したフレーミング像を示す。なお、フレーミング撮影時のICCDカメラの露光時間は0.2ns一定であり、撮影時間は正極性内部線電極近傍へのストリーマヘッドの形成時刻をTnsとして、各撮影像の上部に示している。また、電極への正極性印加パルス電圧の最大波高値は＋100 kV、その立ち上がり及び立ち下がり時間は2ns、その持続時間（半値幅）は5nsであった。 [C-1] Framing imaging image of nanosecond pulse discharge FIG. 8 shows the state of nanosecond pulse discharge in the same coaxial cylindrical electrode as that of pulse discharge framing in FIG. Shows a framing image taken at. Note that the exposure time of the ICCD camera at the time of framing photography is constant 0.2 ns, and the photographing time is shown at the top of each photographed image with the formation time of the streamer head near the positive internal line electrode being Tns. The maximum peak value of the positive polarity applied pulse voltage to the electrode was +100 kV, its rise and fall time was 2 ns, and its duration (half width) was 5 ns.
図8より、一般的なパルス放電同様、パルス電圧印加後、ストリーマヘッドが正極性内部線電極近傍へ形成され（Tns）、その後、接地された外部円筒電極へ向けて進展を開始し、接地極へ到達している（T+3ns）ことが確認される。しかしながら、一般的なパルス放電と同様に、このストリーマヘッドの接地極への到達とともに、放電様相がグロー様放電へ移行することはなく、パルス電圧の高速な立ち下りとともに放電は終了している。なお、パルス放電同様、再度のストリーマヘッドの形成（T+1ns）とその外部円筒電極へ向けた進展（T+2-3ns）は確認される。即ち、図8よりナノ秒パルス放電はストリーマ放電のみで構成されていることが確認される。 As shown in FIG. 8, after applying the pulse voltage, the streamer head is formed in the vicinity of the positive internal line electrode (Tns) after the pulse voltage is applied, and then progresses toward the grounded external cylindrical electrode. (T + 3ns) is confirmed. However, as with a general pulse discharge, the discharge phase does not shift to a glow-like discharge as the streamer head reaches the ground electrode, and the discharge ends with a fast fall of the pulse voltage. As with the pulse discharge, the formation of the streamer head again (T + 1ns) and its progress toward the external cylindrical electrode (T + 2-3ns) are confirmed. That is, it is confirmed from FIG. 8 that the nanosecond pulse discharge is composed of only the streamer discharge.
［Ｃ－２］ナノ秒パルス放電のストリーク撮影像
図9には、図8のフレーミング撮影と同一条件にて撮影したナノ秒パルス放電のストリーク撮影像を示す。このストリーク撮影像において、上端及び下端は、図3同様、同軸円筒電極の接地された外部電極内表面及び正極性の内部電極外表面と一致しており、横軸は経過時間を示している。なお、経過時間においてはストリーマヘッドの正極性内部線電極近傍への形成時刻を0nsとしている。 [C-2] Streak image of nanosecond pulse discharge FIG. 9 shows a streak image of nanosecond pulse discharge imaged under the same conditions as the framing image of FIG. In this streak image, the upper end and the lower end coincide with the grounded outer electrode inner surface and the positive inner electrode outer surface of the coaxial cylindrical electrode, as in FIG. 3, and the horizontal axis indicates the elapsed time. In the elapsed time, the formation time of the streamer head near the positive internal line electrode is set to 0 ns.
図9より、［Ｃ－１］の記述と同様のナノ秒パルス放電の様子が確認される。また、ストリーマ放電期間においてストリーマヘッドがほぼ等速で電極間を進展していることが確認される。図10には、図8のフレーミング撮影像におけるストリーマヘッドの位置と各撮影時間との関係を示す。図10からも、図9同様、ナノ秒パルス放電においてストリーマヘッドが等速進展していることが確認される。なお、その進展速度は8.8mm/nsであり、パルス放電における進展速度の約5倍である。これは、パルス電圧の立ち上がりがナノ秒となることで、電極間へ100 kVという高電圧を印加することが出来たためである。図１１には、電極長２００ｍｍと８００ｍｍの同軸円筒電極（内部電極外径０．５ｍｍ、外部電極内径７６ｍｍ）中へナノ秒パルス放電を形成した場合の電極インピーダンス（Ａ）及びその算出に用いた電極への印加電圧・電流波形（Ｂ:電極長２００ｍｍ、Ｃ：８００ｍｍ）を示す。図１１Ａから、ナノ秒パルス放電において電極インピーダンスが約０．３ｋΩ一定となっていることが確認される。 FIG. 9 confirms the state of nanosecond pulse discharge similar to that described in [C-1]. Further, it is confirmed that the streamer head advances between the electrodes at a substantially constant speed during the streamer discharge period. FIG. 10 shows the relationship between the position of the streamer head in the framing shot image of FIG. 8 and each shooting time. FIG. 10 also confirms that the streamer head progresses at a constant speed in the nanosecond pulse discharge, as in FIG. The progress rate is 8.8 mm / ns, which is about 5 times the progress rate in pulse discharge. This is because a high voltage of 100 kV could be applied between the electrodes because the rise of the pulse voltage was nanoseconds. FIG. 11 shows the electrode impedance (A) when nanosecond pulse discharge is formed in coaxial cylindrical electrodes (inner electrode outer diameter 0.5 mm, outer electrode inner diameter 76 mm) having electrode lengths of 200 mm and 800 mm, and used for calculation thereof. An applied voltage / current waveform to an electrode (B: electrode length 200 mm, C: 800 mm) is shown. FIG. 11A confirms that the electrode impedance is constant at about 0.3 kΩ in nanosecond pulse discharge.
［Ｃ－３］ナノ秒パルス放電に関するまとめ
表2に、ナノ秒パルス放電に関する諸特性をまとめる。表2より、ナノ秒パルス放電は、ストリーマ放電のみで構成されており、パルス放電におけるグロー様放電時に発生していた気体加熱に伴うエネルギー損失を排除できたことが確認された。また、ナノ秒パルス放電時の放電インピーダンスが、パルス放電時とは異なり、0.3kΩ一定となることが確認される(図１１参照)。これはストリーマヘッドの進展速度が高速かつ等速となったことによると考えられる。よって、ナノ秒パルス放電は、パルス放電による非熱平衡プラズマ形成時の低エネルギー効率の要因であったパルス電源と放電電極との不整合（上記例では、特性インピーダンスが0.3kΩとなるようなパルス電源を用意することでインピーダンス整合が可能となる）及びグロー様放電時の熱損失の両要因を解消したと言える。
Figure JPOXMLDOC01-appb-T000002
 [C-3] Summary of nanosecond pulse discharge Table 2 summarizes various characteristics of nanosecond pulse discharge. From Table 2, it was confirmed that the nanosecond pulse discharge consisted of only the streamer discharge and was able to eliminate the energy loss accompanying the gas heating that occurred during the glow-like discharge in the pulse discharge. Also, it is confirmed that the discharge impedance during nanosecond pulse discharge is constant at 0.3 kΩ, unlike during pulse discharge (see FIG. 11). This is thought to be due to the fact that the progress speed of the streamer head is high and constant. Therefore, the nanosecond pulse discharge is a mismatch between the pulse power source and the discharge electrode, which was a factor of low energy efficiency during non-thermal equilibrium plasma formation by pulse discharge (in the above example, the pulse power source whose characteristic impedance is 0.3 kΩ) This makes it possible to match both the impedance and the heat loss during glow-like discharge.
Figure JPOXMLDOC01-appb-T000002
［Ｄ］ナノ秒パルス放電による非熱平衡プラズマの形成
［Ｄ－１］ナノ秒パルス放電による排ガス処理
図１２にはパルス放電プラズマ及びナノ秒パルス放電プラズマによるNO処理結果を示す。実験は、模擬排ガスをその組成N2Balance/NO200ppm/O25%/H2O2%、その流量2.0 L/minにて、内部電極外径0.5 mm、外部電極内径76 mm、電極長500 mm（ナノ秒パルス放電処理の場合は800 mmとなる）の同軸円筒型電極へ流し、一般的なパルス電源（時間幅：40-120ns）及びナノ秒パルス電源（時間幅：5ns）により電極間へ非熱平衡プラズマを形成することで実施した。図１２の縦軸は電極への注入エネルギーに対するNO処理エネルギー効率であり、横軸はNO除去率である。よって、グラフの右上ほど除去能力及び除去エネルギー効率が優れていることを意味する。 [D] Formation of non-thermal equilibrium plasma by nanosecond pulse discharge [D-1] Exhaust gas treatment by nanosecond pulse discharge FIG. 12 shows NO treatment results by pulse discharge plasma and nanosecond pulse discharge plasma. In the experiment, the simulated exhaust gas was composed of N 2 Balance / NO 200 ppm / O 2 5% / H 2 O 2%, flow rate 2.0 L / min, inner electrode outer diameter 0.5 mm, outer electrode inner diameter 76 mm, electrode length 500 mm. It flows to the coaxial cylindrical electrode (800 mm in the case of nanosecond pulse discharge treatment), and between the electrodes by a general pulse power supply (time width: 40-120 ns) and nanosecond pulse power supply (time width: 5 ns) This was done by forming a non-thermal equilibrium plasma. The vertical axis in FIG. 12 is the NO treatment energy efficiency relative to the energy injected into the electrode, and the horizontal axis is the NO removal rate. Therefore, it means that the removal capability and the removal energy efficiency are excellent in the upper right of the graph.
図１２より、全てのパルス時間幅においてNO除去率の増加とともにNO除去エネルギー効率が減少していることが確認される。これは、NO除去の進行とともに、NOとNO処理の担い手である化学的活性種との反応率が低下するためである。また、同一NO除去率において、パルス時間幅の減少とともに、NO除去エネルギー効率が改善していることが確認される。ここで、120nsから40nsへのパルス時間幅の短縮化に伴うNO除去エネルギー効率の改善は、パルス放電におけるグロー様放電時間の短縮に伴う熱損失の低減に起因しており、ナノ秒パルス放電によるNO除去エネルギー効率の改善は、グロー様放電による熱損失が皆無であること及び印加電圧の高電圧化に伴う化学的活性種の生成効率向上に起因すると考えられる。ナノ秒パルス放電によるNO処理エネルギー効率の典型例としては、NO除去率60%（初期NO濃度：200 ppm）にて2.5 mol-NO/kWh（＝75 g-NO/kWh）が挙げられる。 From FIG. 12, it is confirmed that the NO removal energy efficiency decreases as the NO removal rate increases in all pulse time widths. This is because with the progress of NO removal, the reaction rate between NO and chemically active species that are responsible for NO treatment decreases. Further, it is confirmed that the NO removal energy efficiency is improved with the decrease of the pulse time width at the same NO removal rate. Here, the improvement in NO removal energy efficiency accompanying the shortening of the pulse time width from 120 ns to 40 ns is due to the reduction of heat loss due to the shortening of the glow-like discharge time in the pulse discharge, which is caused by the nanosecond pulse discharge. The improvement in NO removal energy efficiency is considered to be due to the fact that there is no heat loss due to glow-like discharge and the improvement in the generation efficiency of chemically active species accompanying the increase in applied voltage. A typical example of NO treatment energy efficiency by nanosecond pulse discharge is 2.5 mol-NO / kWh (= 75 g-NO / kWh) at an NO removal rate of 60% (initial NO concentration: 200 ： ppm).
［Ｄ－２］ナノ秒パルス放電によるオゾン生成
図１３にはナノ秒パルス放電プラズマ及び他の電気的放電プラズマによる空気原料オゾナイザーの特性マップを示す。本マップは縦軸に電極への注入エネルギーに対するオゾン生成エネルギー効率、横軸にオゾン生成濃度を取っており、マップの右上に位置するほど優れたオゾナイザーとなる。なお、ナノ秒パルス放電プラズマによるオゾン生成条件は、原料乾燥空気流量が1.0 L/min、同軸円筒型電極のパラメータが内部電極外径0.5mm、外部電極内径76mm、電極長200mmである。図１３より、現在高性能オゾナイザーとして期待されている極短ギャップでの誘電体バリア放電に対して、オゾン生成エネルギー効率の面においてナノ秒パルス放電プラズマの優位性が確認される。また、ナノ秒パルス放電プラズマによる190g/kWhというオゾン生成エネルギー効率は、誘電体バリア放電によるオゾン生成の理論エネルギー効率に匹敵する値であり、現存するオゾン生成エネルギー効率データの最高値である。 [D-2] Ozone generation by nanosecond pulse discharge FIG. 13 shows a characteristic map of an air source ozonizer by nanosecond pulse discharge plasma and other electrical discharge plasma. In this map, the vertical axis represents the ozone generation energy efficiency relative to the energy injected into the electrode, and the horizontal axis represents the ozone generation concentration. The higher the position on the upper right of the map, the better the ozonizer. The ozone generation conditions by the nanosecond pulse discharge plasma are as follows: the raw material dry air flow rate is 1.0 L / min, the parameters of the coaxial cylindrical electrode are the inner electrode outer diameter 0.5 mm, the outer electrode inner diameter 76 mm, and the electrode length 200 mm. FIG. 13 confirms the superiority of nanosecond pulsed discharge plasma in terms of ozone generation energy efficiency over dielectric barrier discharge in an extremely short gap that is currently expected as a high performance ozonizer. Moreover, the ozone generation energy efficiency of 190 g / kWh by the nanosecond pulse discharge plasma is comparable to the theoretical energy efficiency of ozone generation by the dielectric barrier discharge, and is the highest value of the existing ozone generation energy efficiency data.
図１４に、０．５ｎｓ電源の出力波形（負荷：１００Ω、極性：負）を示す。実験条件は、ブルームライン型線路の長さを除き、段落００２５と同条件である。実験装置におけるブルームライン型線路の長さは５０ｍｍである。０．０５～０．２０ＭＰａは、ギャップスイッチ内の圧力を示しており、本圧力により出力電圧を制御している。図１４から、電圧立ち上がり０．５ns、電圧立ち下がり０．５ns、電圧持続時間１ns（半値幅）であることが読み取れる。 FIG. 14 shows an output waveform (load: 100Ω, polarity: negative) of the 0.5 ns power supply. The experimental conditions are the same as those in paragraph 0025 except for the length of the bloom line type line. The length of the bloom line type line in the experimental apparatus is 50 mm. 0.05 to 0.20 MPa indicates the pressure in the gap switch, and the output voltage is controlled by this pressure. It can be seen from FIG. 14 that the voltage rise is 0.5 ns, the voltage fall is 0.5 ns, and the voltage duration is 1 ns (half-value width).
本発明に係る放電方法及び装置は、産業排気ガスの浄化やオゾン生成、燃焼ガスの改質、燃焼状態の改善、燃焼排ガスの浄化に利用することができる。 The discharge method and apparatus according to the present invention can be used for industrial exhaust gas purification, ozone generation, combustion gas reforming, combustion state improvement, and combustion exhaust gas purification.
非熱平衡プラズマ形成システムのブロック図であり、上図は誘電体バリア放電システム、下図はパルス放電システム、である。It is a block diagram of a non-thermal equilibrium plasma formation system, the upper figure is a dielectric barrier discharge system, and the lower figure is a pulse discharge system. パルス発生装置の概略図である。It is the schematic of a pulse generator. パルス放電のフレーミング像を示す図である。It is a figure which shows the framing image of pulse discharge. パルス放電のストリーク像を示す図である。It is a figure which shows the streak image of pulse discharge. ストリーマヘッド進展速度の印加電圧依存性を示す図である。It is a figure which shows the applied voltage dependence of the streamer head progress speed. パルス放電時の印加電圧及び放電電流波形を示す図である。It is a figure which shows the applied voltage and discharge current waveform at the time of pulse discharge. パルス放電時の電極間インピーダンス波形を示す図である。It is a figure which shows the impedance waveform between electrodes at the time of pulse discharge. パルス放電時の電極内気体温度の経時変化を示す図である。It is a figure which shows the time-dependent change of the gas temperature in an electrode at the time of pulse discharge. ナノパルス放電フレーミング像を示す図である。It is a figure which shows a nano pulse discharge framing image. ナノ秒パルス放電のストリーク像を示す図である。It is a figure which shows the streak image of nanosecond pulse discharge. ナノ秒パルス放電におけるストリーマヘッド位置の時間依存性を示す図である。It is a figure which shows the time dependence of the streamer head position in nanosecond pulse discharge. (A)はナノ秒パルス放電におけるストリーマ放電時の電極間インピーダンス波形（電極長が200mm、800mm）を示す図である。(B)はナノ秒パルス放電時の印加電圧及び放電電流波形（電極長200mm）を示す図である。(C)はナノ秒パルス放電時の印加電圧及び放電電流波形（電極長800mm）を示す図である。(A) is a figure which shows the impedance waveform between electrodes at the time of the streamer discharge in nanosecond pulse discharge (electrode length is 200 mm, 800 mm). (B) is a figure which shows the applied voltage and discharge current waveform (electrode length 200mm) at the time of nanosecond pulse discharge. (C) is a figure which shows the applied voltage and discharge current waveform (electrode length 800mm) at the time of nanosecond pulse discharge. パルス放電プラズマによるNO処理結果を示す図である。It is a figure which shows the NO process result by pulse discharge plasma. 放電プラズマによる空気原料オゾナイザーの特性マップを示す図である。It is a figure which shows the characteristic map of the air raw material ozonizer by discharge plasma. 他のサブナノ秒パルス電源による出力波形を示す。The output waveform by other subnanosecond pulse power supplies is shown.

Claims (24)

  1. 　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間が１０ns以下のパルスを生成するパルス電源と、を用意し、
    　立ち上り時間が１０ns以下のパルス電圧を前記電極間に印加することで第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
    　電極間距離に対応して、パルスの持続時間、印加電圧を選択することで、進展するストリーマヘッドが前記第２の電極に到達する時に放電を終了させる、
    　パルス放電発生方法。     Preparing a discharge electrode including a first electrode and a second electrode, and a pulse power source for generating a pulse having a rise time of 10 ns or less;
    By applying a pulse voltage having a rise time of 10 ns or less between the electrodes, the streamer head is advanced from the first electrode to the second electrode at a constant speed,
    Corresponding to the distance between the electrodes, by selecting the duration of the pulse, the applied voltage, the discharge is terminated when the developing streamer head reaches the second electrode,
    Pulse discharge generation method.
  2. 　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間がストリーマヘッド形成時間より短いパルスを生成するパルス電源と、を用意し、
    　前記パルス電源からパルス電圧を前記電極間に印加することで第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
    　電極間距離に対応して、パルスの持続時間、印加電圧を選択することで、進展するストリーマヘッドが前記第２の電極に到達する時に放電を終了させる、
    　パルス放電発生方法。     Preparing a discharge electrode comprising a first electrode and a second electrode, and a pulse power supply for generating a pulse whose rise time is shorter than the streamer head formation time;
    By applying a pulse voltage from the pulse power source between the electrodes, a streamer head is developed at a constant speed from the first electrode to the second electrode,
    Corresponding to the distance between the electrodes, by selecting the duration of the pulse, the applied voltage, the discharge is terminated when the developing streamer head reaches the second electrode,
    Pulse discharge generation method.
  3. 　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間が１０ns以下のパルスを生成するパルス電源と、を用意し、
    　立ち上り時間が１０ns以下のパルス電圧を電極間に印加してストリーマ放電を生成して、第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
    　電極間距離に対応して、パルスの持続時間、印加電圧を選択することで、ストリーマ放電の時間の１．５倍の時間内に放電を終了させる、
    　パルス放電発生方法。     Preparing a discharge electrode including a first electrode and a second electrode, and a pulse power source for generating a pulse having a rise time of 10 ns or less;
    Applying a pulse voltage having a rise time of 10 ns or less between the electrodes to generate a streamer discharge, and causing the streamer head to advance at a constant speed from the first electrode to the second electrode;
    By selecting the duration of the pulse and the applied voltage according to the distance between the electrodes, the discharge is terminated within 1.5 times the streamer discharge time.
    Pulse discharge generation method.
  4. 　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間がストリーマヘッド形成時間より短いパルスを生成するパルス電源と、を用意し、
    　前記パルス電源からパルス電圧を電極間に印加してストリーマ放電を生成して、第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
    　電極間距離に対応して、パルスの持続時間、印加電圧を選択することで、ストリーマ放電の時間の１．５倍の時間内に放電を終了させる、
    　パルス放電発生方法。     Preparing a discharge electrode comprising a first electrode and a second electrode, and a pulse power supply for generating a pulse whose rise time is shorter than the streamer head formation time;
    A pulse voltage is applied between the electrodes from the pulse power source to generate a streamer discharge, and a streamer head is developed at a constant speed from the first electrode to the second electrode,
    By selecting the duration of the pulse and the applied voltage according to the distance between the electrodes, the discharge is terminated within 1.5 times the streamer discharge time.
    Pulse discharge generation method.
  5. 　放電をストリーマ放電のみで行なう請求項３、４いずれかに記載のパルス放電発生方法。 The pulse discharge generation method according to claim 3, wherein the discharge is performed only with a streamer discharge.
  6. 　第１の電極と第２の電極とを備えた放電電極と、パルスを生成するパルス電源と、を用意し、
    　前記パルス電源からパルス電圧を電極間に印加して第１の電極から第２の電極へストリーマヘッドを進展させてストリーマ放電を生成し、ストリーマ放電の間における前記パルス電圧をほぼ一定とすることで電極間インピーダンスをほぼ一定とする、
    　パルス放電発生方法。     Preparing a discharge electrode including a first electrode and a second electrode, and a pulse power source for generating a pulse;
    Applying a pulse voltage from the pulse power source between the electrodes to develop a streamer head from the first electrode to the second electrode to generate a streamer discharge, and making the pulse voltage between the streamer discharges substantially constant The interelectrode impedance is almost constant,
    Pulse discharge generation method.
  7. 　前記パルスは、立ち上り時間が１０ns以下のパルスである、請求項６に記載のパルス放電発生方法。 The pulse discharge generation method according to claim 6, wherein the pulse is a pulse having a rise time of 10 ns or less.
  8. 　前記パルスは、立ち上り時間がストリーマヘッド形成時間より短いパルスである、請求項６、７いずれかに記載のパルス放電発生方法。 The pulse discharge generation method according to claim 6, wherein the pulse is a pulse whose rise time is shorter than the streamer head formation time.
  9. 　前記パルスの立ち下り時間が１０ns以下である、請求項１乃至８いずれかに記載のパルス放電発生方法。 The pulse discharge generation method according to any one of claims 1 to 8, wherein a fall time of the pulse is 10 ns or less.
  10. 　前記パルス電源の特性インピーダンスと、ストリーマヘッド進展時の電極間インピーダンスと、が整合されている、請求項１乃至９いずれかに記載のパルス放電発生方法。 The pulse discharge generation method according to any one of claims 1 to 9, wherein the characteristic impedance of the pulse power source and the inter-electrode impedance when the streamer head progresses are matched.
  11. 　請求項１乃至１０いずれかに記載のパルス放電発生方法を用いて、前記電極間に供給した被処理ガスを処理する、ガス処理方法。 A gas processing method of processing a gas to be processed supplied between the electrodes using the pulse discharge generation method according to any one of claims 1 to 10.
  12. 　請求項１乃至１０いずれかに記載のパルス放電発生方法を用いて、前記電極間に供給した酸素あるいは空気からオゾンを生成する、オゾン生成方法。 An ozone generation method for generating ozone from oxygen or air supplied between the electrodes using the pulse discharge generation method according to any one of claims 1 to 10.
  13. 　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間が１０ns以下のパルスを生成するパルス電源と、からなる放電発生装置であって、
    　前記パルス電源は、立ち上り時間が１０ns以下のパルス電圧を前記電極間に印加することで第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
    　パルスの持続時間、印加電圧は、電極間距離に対応して、進展するストリーマヘッドが前記第２の電極に到達する時に放電が終了するように選択されている、
    　パルス放電発生装置。     A discharge generator comprising: a discharge electrode comprising a first electrode and a second electrode; and a pulse power supply that generates a pulse having a rise time of 10 ns or less,
    The pulse power source causes a streamer head to advance at a constant speed from the first electrode to the second electrode by applying a pulse voltage having a rise time of 10 ns or less between the electrodes,
    The duration of the pulse, the applied voltage is selected such that the discharge ends when the evolving streamer head reaches the second electrode, corresponding to the distance between the electrodes,
    Pulse discharge generator.
  14. 　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間がストリーマヘッド形成時間より短いパルスを生成するパルス電源と、からなる放電発生装置であって、
    　前記パルス電源は、立ち上り時間がストリーマヘッド形成時間より短いパルス電圧を前記電極間に印加することで第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
    　パルスの持続時間、印加電圧は、電極間距離に対応して、進展するストリーマヘッドが前記第２の電極に到達する時に放電が終了するように選択されている、
    　パルス放電発生装置。     A discharge generator comprising: a discharge electrode including a first electrode and a second electrode; and a pulse power source that generates a pulse whose rise time is shorter than a streamer head formation time,
    The pulse power supply causes the streamer head to advance at a constant speed from the first electrode to the second electrode by applying a pulse voltage between the electrodes whose rise time is shorter than the streamer head formation time,
    The duration of the pulse, the applied voltage is selected such that the discharge ends when the evolving streamer head reaches the second electrode, corresponding to the distance between the electrodes,
    Pulse discharge generator.
  15. 　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間が１０ns以下のパルスを生成するパルス電源と、からなる放電発生装置であって、
    　前記パルス電源は、立ち上り時間が１０ns以下のパルス電圧を電極間に印加してストリーマ放電を生成して、第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
    　パルスの持続時間、印加電圧は、電極間距離に対応して、ストリーマ放電の時間の１．５倍の時間内に放電が終了するように選択されている、
    　パルス放電発生装置。     A discharge generator comprising: a discharge electrode comprising a first electrode and a second electrode; and a pulse power supply that generates a pulse having a rise time of 10 ns or less,
    The pulse power supply generates a streamer discharge by applying a pulse voltage having a rise time of 10 ns or less between the electrodes, and advances the streamer head from the first electrode to the second electrode at a constant speed.
    The duration of the pulse and the applied voltage are selected to finish the discharge within 1.5 times the streamer discharge time, corresponding to the distance between the electrodes.
    Pulse discharge generator.
  16. 　第１の電極と第２の電極とを備えた放電電極と、立ち上り時間がストリーマヘッド形成時間より短いパルスを生成するパルス電源と、からなる放電発生装置であって、
    　前記パルス電源は、立ち上り時間がストリーマヘッド形成時間より短いパルス電圧を電極間に印加してストリーマ放電を生成して、第１の電極から第２の電極へストリーマヘッドを等速で進展させ、
    　パルスの持続時間、印加電圧は、電極間距離に対応して、ストリーマ放電の時間の１．５倍の時間内に放電が終了するように選択されている、
    　パルス放電発生装置。     A discharge generator comprising: a discharge electrode comprising a first electrode and a second electrode; and a pulse power source that generates a pulse whose rise time is shorter than the streamer head formation time,
    The pulse power supply generates a streamer discharge by applying a pulse voltage between the electrodes with a rise time shorter than the streamer head formation time, and advances the streamer head from the first electrode to the second electrode at a constant speed,
    The duration of the pulse, the applied voltage, is selected so that the discharge ends within 1.5 times the streamer discharge time, corresponding to the distance between the electrodes,
    Pulse discharge generator.
  17. 　放電はストリーマ放電のみからなる請求項１５、１６いずれかに記載のパルス放電発生装置。 The pulse discharge generator according to any one of claims 15 and 16, wherein the discharge comprises only a streamer discharge.
  18. 　第１の電極と第２の電極とを備えた放電電極と、パルスを生成するパルス電源と、からなる放電発生装置であって、
    　前記パルス電源からパルス電圧を電極間に印加して第１の電極から第２の電極へストリーマヘッドを進展させてストリーマ放電を生成し、ストリーマ放電の間における前記パルス電圧をほぼ一定とすることで電極間インピーダンスをほぼ一定とするように構成された、
    　パルス放電発生装置。     A discharge generator comprising a discharge electrode comprising a first electrode and a second electrode, and a pulse power source for generating a pulse,
    Applying a pulse voltage from the pulse power source between the electrodes to develop a streamer head from the first electrode to the second electrode to generate a streamer discharge, and making the pulse voltage between the streamer discharges substantially constant Configured to make the interelectrode impedance almost constant,
    Pulse discharge generator.
  19. 　前記パルスは、立ち上り時間が１０ns以下のパルスである、請求項１８に記載のパルス放電発生装置。 The pulse discharge generator according to claim 18, wherein the pulse is a pulse having a rise time of 10 ns or less.
  20. 　前記パルスは、立ち上り時間がストリーマヘッド形成時間より短いパルスである、請求項１８、１９いずれかに記載のパルス放電発生方法。 20. The pulse discharge generation method according to claim 18, wherein the pulse is a pulse whose rise time is shorter than a streamer head formation time.
  21. 　前記パルスの立ち下り時間が１０ns以下である、請求項１３乃至１９いずれかに記載のパルス放電発生装置。 The pulse discharge generator according to any one of claims 13 to 19, wherein a fall time of the pulse is 10 ns or less.
  22. 　前記パルス電源の特性インピーダンスと、ストリーマヘッド進展時の電極間インピーダンスと、が整合されている、請求項１３乃至２１いずれかに記載のパルス放電発生装置。 The pulse discharge generator according to any one of claims 13 to 21, wherein the characteristic impedance of the pulse power source and the inter-electrode impedance when the streamer head progresses are matched.
  23. 　請求項１３乃至２２いずれかに記載のパルス放電発生装置を用いて、前記電極間に供給した被処理ガスを処理するように構成されている、ガス処理装置。 A gas processing apparatus configured to process a gas to be processed supplied between the electrodes using the pulse discharge generator according to any one of claims 13 to 22.
  24. 　請求項１３乃至２２いずれかに記載のパルス放電発生装置を用いて、前記電極間に供給した酸素あるいは空気からオゾンを生成するように構成されている、オゾン生成装置。 23. An ozone generator configured to generate ozone from oxygen or air supplied between the electrodes using the pulse discharge generator according to claim 13.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015161194A (en) * 2014-02-26 2015-09-07 マツダ株式会社 direct-injection gasoline engine
US10160668B2 (en) 2014-05-20 2018-12-25 Japan Oil, Gas And Metals National Corporation Device and method for treating organic-material-containing water
JP2019011499A (en) * 2017-06-30 2019-01-24 国立大学法人 熊本大学 Method for producing metal nanoparticle

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07265654A (en) * 1994-03-31 1995-10-17 Hitachi Zosen Corp Plasma producing method in plasma-process waste gas purifying device
JPH10110936A (en) * 1996-10-08 1998-04-28 Hitachi Ltd Gas processing device
JP2000354737A (en) * 1999-04-16 2000-12-26 Mitsubishi Heavy Ind Ltd Device and method for decomposing harmful component
JP2001517546A (en) * 1997-09-19 2001-10-09 エイイーエイ テクノロジー パブリック リミテッド カンパニー Corona discharge reactor
JP2005222779A (en) * 2004-02-04 2005-08-18 Ngk Insulators Ltd Plasma processing device

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09156904A (en) * 1995-12-13 1997-06-17 Meidensha Corp Ozone generator
JP3982044B2 (en) * 1998-03-06 2007-09-26 日新電機株式会社 Ozone generation method
JPH11276842A (en) * 1998-03-30 1999-10-12 Toshiba Corp Gas purification apparatus
JP2000126542A (en) * 1998-10-22 2000-05-09 Mitsubishi Heavy Ind Ltd Plasma waste gas treatment facility and gas reaction acceleration facility
JP3359016B2 (en) * 2000-02-18 2002-12-24 三菱重工業株式会社 Ash and soil detoxification method and detoxification equipment
JP3377777B2 (en) * 2000-06-29 2003-02-17 三菱重工業株式会社 Ash and soil detoxification method and detoxification equipment
JP2004350709A (en) * 2003-05-27 2004-12-16 Matsushita Electric Ind Co Ltd Air cleaner

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07265654A (en) * 1994-03-31 1995-10-17 Hitachi Zosen Corp Plasma producing method in plasma-process waste gas purifying device
JPH10110936A (en) * 1996-10-08 1998-04-28 Hitachi Ltd Gas processing device
JP2001517546A (en) * 1997-09-19 2001-10-09 エイイーエイ テクノロジー パブリック リミテッド カンパニー Corona discharge reactor
JP2000354737A (en) * 1999-04-16 2000-12-26 Mitsubishi Heavy Ind Ltd Device and method for decomposing harmful component
JP2005222779A (en) * 2004-02-04 2005-08-18 Ngk Insulators Ltd Plasma processing device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015161194A (en) * 2014-02-26 2015-09-07 マツダ株式会社 direct-injection gasoline engine
US10160668B2 (en) 2014-05-20 2018-12-25 Japan Oil, Gas And Metals National Corporation Device and method for treating organic-material-containing water
JP2019011499A (en) * 2017-06-30 2019-01-24 国立大学法人 熊本大学 Method for producing metal nanoparticle
JP7114039B2 (en) 2017-06-30 2022-08-08 国立大学法人 熊本大学 METHOD FOR MANUFACTURING METAL NANOPARTICLES

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