JP2010274167A - Water treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water treatment apparatus in which has energy efficiency is improved by employing a pulsed power generation unit excellent in energy transfer efficiency. <P>SOLUTION: The pulsed power generation unit 8 comprises a high-voltage DC power source 81, a capacitor 82, resistors 83 and 84, a semiconductor switch 85 and a trigger oscillator 86. A current from the high-voltage DC power source 81 is supplied to the capacitor 82 via the resistor 83 to charge the capacitor 82. When the semiconductor switch 85 is switched at high speed by a trigger pulse to be supplied from the trigger oscillator 86, the electric charge stored in the capacitor 82 is discharged to output a high-voltage pulse between terminals 87 and 88. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a water treatment apparatus for decomposing organic substances and microorganisms contained in clean water, sewage, waste water, and the like by using active species such as radicals generated by discharge and ozone.

  Conventionally, ozone has been used for treatments such as oxidative decomposition, sterilization, and deodorization of organic substances in water in fields such as clean water, sewage, industrial wastewater, and pools. However, ozone has a weak oxidizing power and cannot be mineralized even if it can be made hydrophilic and low molecular. In addition, hardly decomposable organic substances such as dioxins cannot be decomposed.

  Therefore, in order to improve the treatment capacity, ozone is generated by discharge, and OH radicals, O radicals, etc., which have stronger oxidizing power than ozone are generated, and the water to be treated is exposed to a discharge space containing the ozone and radicals. A water treatment apparatus has been proposed in which oxidation treatment is performed not only by ozone but also by radicals (see, for example, Patent Document 1).

  In the water treatment apparatus described above, streamer discharge, which is a kind of plasma discharge, is generated using a pulse power generator. Specifically, a pulsed high voltage (hereinafter referred to as “high voltage pulse”) is generated by instantaneously discharging the charge stored in the capacitor, and the high voltage pulse is separated at a predetermined interval. The streamer discharge is generated by applying between the electrodes arranged in the same manner.

  The inventors use a device combining a trigger tron gap switch and a pulse transformer as the pulse power generation device described above, and discharge the electric charge charged in the capacitor by the trigger tron gap switch, and further output the high voltage pulse output. The voltage is boosted by a pulse transformer (see Non-Patent Document 1).

JP 2000-279977 A

Proceedings of the 2008 Annual Meeting of the Electrostatic Society of Japan, page 183 “Effect of water droplet formation and water droplet position on air pulse discharge water treatment” Author: Kobayashi Tsutomu et al.

  However, the above-described conventional pulse power generator has low energy efficiency of the water treatment device, that is, the ratio of decomposing organic substances in the water to be treated is low with respect to the charging energy input to the capacitor, thus improving the energy efficiency. Was requested.

  The present invention has been made in view of such circumstances, and provides a water treatment device with improved energy efficiency by employing a pulse power generator excellent in energy transfer efficiency.

In order to achieve the above object, a water treatment apparatus according to the present invention comprises:
A cylindrical electrode and a linear electrode disposed along the central axis of the cylindrical electrode are provided, and a pulsed high voltage is applied between both electrodes from a pulse power generator to form a discharge space. A water treatment device that oxidizes the water to be treated by passing water droplets of the water to be treated in the discharge space,
The pulse power generator is
DC power supply,
A capacitor that is charged by the current from the DC power supply;
A trigger oscillator capable of generating pulses and adjusting the number of repetitions of the pulses;
And a semiconductor switch that is connected to the capacitor and instantaneously releases the electric charge charged in the capacitor when a pulse output from the trigger oscillator is input.

  Here, it is preferable to use a MOS FET as the semiconductor switch. The DC power source is preferably adjustable in voltage.

  In the present invention, a high voltage pulse is generated by instantaneously discharging a charge supplied from a DC power source and charged in a capacitor using a semiconductor switch, thereby improving the energy transfer efficiency of the pulse power generator. In this way, the energy efficiency of the water treatment device is improved.

It is sectional drawing which shows the structure of the water treatment apparatus concerning embodiment of this invention. It is a top view of the injection part of the water treatment apparatus of FIG. It is a circuit diagram which shows the structure of the pulse power generator of the water treatment apparatus of FIG. It is a circuit diagram which shows the structure of the pulse power generator used with the conventional water treatment apparatus. It is a figure which shows the voltage waveform and current waveform of a pulse power generator. It is a figure which shows the change of the decomposition rate with respect to processing time. It is a figure which shows the change of the decomposition rate with respect to the repetition number in processing time 30 second, and the change of the decomposition rate with respect to discharge electric power. It is a figure which shows the change of the decomposition rate with respect to the repetition number in processing time 60 second, and the change of the decomposition rate with respect to discharge electric power. It is a figure which shows the change of the energy transfer efficiency with respect to the repetition number. It is a figure which shows the change of the decomposition rate by processing time, and the change of the decomposition rate by charging energy. It is a figure which shows the change of the decomposition rate by processing time, and the change of the decomposition rate by charging energy.

  Hereinafter, a water treatment apparatus according to an embodiment of the present invention will be described with reference to the drawings.

<Configuration and operation of water treatment device>
FIG. 1 is a cross-sectional view showing a configuration of a water treatment apparatus according to an embodiment of the present invention. A water treatment apparatus 1 according to this embodiment includes a container 2, a cylindrical electrode 3, a linear electrode 4, a water tank 5 to be treated, a pump 6, a shower nozzle 7, a pulse power generator 8, and a water tank storage box. 9 is included.

  The container 2 includes a cylindrical container body 21, a lower lid portion 22 disposed at the lower end of the container body 21, and an upper lid portion 23 disposed at the upper end of the container body 21. It is made of an insulating material such as.

  The lower lid portion 22 is attached to the periphery of the opening portion 91 of the treated water tank storage box 9 so as to close the opening portion 91. A water passage hole 22 a is provided at the center of the lower lid portion 22. On the other hand, the upper cover part 23 is arrange | positioned so that the upper end of the container main body 21 may be closed except the shower nozzle installation hole 23a part.

  The cylindrical electrode 3 is disposed on the inner peripheral side of the container main body 21 and has an outer diameter slightly smaller than the inner diameter of the container main body 21. The cylindrical electrode 3 is obtained, for example, by processing a stainless steel net into a cylindrical shape.

  The linear electrode 4 is formed of, for example, a stainless steel wire and is disposed along the central axis of the cylindrical electrode 3. The upper end portion and the lower end portion of the linear electrode 4 are fixed to the container main body 21 via an insulating fixture (not shown).

  The to-be-treated water tank 5 is accommodated in the to-be-treated water tank accommodation box 9 with the water passage hole 22a of the lower lid portion 22 facing from below.

  The pump 6 is disposed in the treated water tank housing box 9 and sends the treated water W in the treated water tank 5 to the shower nozzle 7 through the treated water supply hose 71.

  The shower nozzle 7 injects the water to be treated W sent through the water to be treated supply hose 71 toward the upper opening of the cylindrical electrode 3. Below the shower nozzle 7, a disc-shaped injection section 72 having a large number of injection holes as shown in FIG. A large number of injection holes 72a are opened at a uniform pitch on a circle having a diameter slightly smaller than the inner diameter of the cylindrical electrode 3, and the water to be treated W is sprayed downward from the injection holes 72a. Can do.

  The pair of output terminals of the pulse power generator 8 has a cathode connected to the cylindrical electrode 3 and an anode connected to the linear electrode 4, and applies a high voltage pulse between the cylindrical electrode 3 and the linear electrode 4. To generate a streamer discharge. The configuration of the pulse power generator 8 will be described in detail later with reference to FIG.

  Operation | movement of the water treatment apparatus 1 mentioned above is demonstrated. To-be-treated water tank 5 is pretreated with water to be treated W containing organic matter. Further, a high voltage pulse is applied between the cylindrical electrode 3 and the linear electrode 4 by the pulse power generator 8, and a columnar streamer discharge space is formed in the cylinder of the cylindrical electrode 3.

  The pump 6 is driven, the water to be treated W in the water tank 5 to be treated is sent to the shower nozzle 7 through the hose 71, and the inside of the cylindrical electrode 3 is injected from the injection hole 72 a (see FIG. 2) of the injection unit 72. To spray. The water to be treated W becomes water droplets D by passing through the injection holes 72a and falls in the streamer discharge space.

  Active species such as ozone, OH radicals and O radicals are generated in the streamer discharge space by the discharge, and these droplets D of the water to be treated W ejected from the shower nozzle 7 fall in the discharge space. In contact with the active species, organic substances in each water droplet are efficiently oxidized and decomposed. Oxidation and decomposition processes in the streamer discharge space are repeated by dropping the water to be treated W that has fallen to the lower lid part 22 and collected in the water tank 5 to be treated through the water passage hole 22a.

<Configuration and operation of pulse power generator>
Next, the configuration and operation of the pulse power generator 8 will be described with reference to the circuit diagram of FIG. The pulse power generator 8 includes a high-voltage DC power supply 81, a capacitor 82, resistors 83 and 84, a semiconductor switch 85, and a trigger oscillator 86. The output terminal 87 is connected to the linear electrode 4 shown in FIG. 1, and the output terminal 88 is also connected to the cylindrical electrode 3.

  In the present embodiment, an FET (field effect transistor) switch is used as the semiconductor switch 85, but some semiconductor switches use diodes, thyristors, or the like. Among these semiconductor switches, a switch configured by connecting a plurality of MOS type FETs in series or in parallel has a high switching speed and can operate for a wide range of input voltages and trigger pulse repetition numbers. It is excellent as a pulse source for the water treatment apparatus 1.

  The trigger oscillator 86 supplies a trigger pulse (square wave) of 5V to the semiconductor switch 85. When the trigger pulse is input to the semiconductor switch 85, a high voltage pulse having a pulse width of about 200 nS is output. There is no problem whether the pulse width of the trigger pulse is equal to or less than the pulse width of the high voltage pulse output from the semiconductor switch 85.

  The resistor 83 is for preventing the charging current of the capacitor 82 from exceeding the allowable current of the high-voltage DC power supply 81. The resistor 84 is used for consuming electric charge accumulated between the cylindrical electrode 3 and the linear electrode 4 when the discharge is stopped.

  The operation of the pulse power generator 8 will be described. A current from the high-voltage DC power supply 81 is supplied to the capacitor 82 via the resistor 83, and the capacitor 82 is charged. When the semiconductor switch 85 is switched at high speed by the trigger pulse supplied from the trigger oscillator 86, the charge charged in the capacitor 82 is discharged, and a high voltage pulse is output between the terminals 87 and 88, and the linear electrode 4 and the cylindrical electrode 3 is applied with a high voltage pulse.

  The frequency of the high voltage pulse output between the terminals 87 and 88 (hereinafter referred to as “repetition number”) is controlled by changing the output frequency of the trigger pulse in the trigger oscillator 86. The voltage of the high voltage pulse is controlled by switching the output voltage of the high voltage DC power supply 81.

  For comparison, the configuration and operation of a pulse power generator (hereinafter abbreviated as “conventional pulse power generator”) used in a conventional water treatment apparatus will be described. FIG. 4 shows a circuit diagram of a conventional pulse power generator 10. A conventional pulse power generator 10 includes a high-voltage DC power supply 101, a capacitor 102, a resistor 103, a trigger tron gap switch 104, a pulse transformer 105, and a trigger circuit 106.

  A current from the high-voltage DC power supply 101 is supplied to the capacitor 102 via the resistor 103, and the capacitor 102 is charged. The resistor 103 is provided for the same purpose as the resistor 83 described above. After the capacitor 102 is charged to the target voltage, the trigger tron gap switch 104 is turned on by a high voltage trigger pulse from the trigger circuit 106. At this time, the electric charge charged in the capacitor 102 flows into the primary side of the pulse transformer 105, and a pulse-like induced voltage is generated on the secondary side due to the mutual inductance.

  The high voltage pulse generated on the secondary side of the pulse transformer 105 in this way is applied between the linear electrode 4 and the cylindrical electrode 3 via the terminals 107 and 108.

  The number of repetitions of pulses output between the terminals 107 and 108 is controlled by changing the output frequency of the trigger pulse in the trigger circuit 106. The voltage of the output pulse is controlled by switching the output voltage of the high-voltage DC power supply 101.

  FIG. 5A shows an example of a voltage waveform and a current waveform of a pulse power generator (hereinafter abbreviated as “pulse power generator of the present embodiment”) 8 used in the water treatment apparatus 1 of the present embodiment. Show. The charging voltage to the capacitor 82 of the pulse power generator 8 is 13 kV, and the number of discharge repetitions is 100 pps. FIG. 5B shows an example of a voltage waveform and a current waveform of the conventional pulse power generator 10. The charging voltage to the capacitor 82 of the pulse power generator 10 is 24 kV, and the number of discharge repetitions is 100 pps. In the figure, the horizontal axis shows the elapsed time since the trigger pulse was supplied, and the vertical axis shows the voltage value and the current value.

  While the voltage waveform of the conventional pulse power generation device 10 is a vibration waveform, the voltage waveform of the pulse power generation device 8 of the present embodiment is a waveform that gradually falls after first rising. .

<Change in decomposition rate with respect to processing time>
Next, the decomposition rate of the structure showing blue when the indigo carmine solution is discharged using the pulse power generator 8 of the present embodiment will be described in comparison with the conventional pulse power generator 10. The decomposition rate was calculated based on the result of measuring the transmittance for each treatment time of the treated sample water.

式（１）において、εｄＣは吸光度を示し、εはモル吸光係数で、物質特有の定数である。 First, a method for calculating the decomposition rate will be described. The decomposition rate was calculated from the measured transmittance using the Lambert-Beer law. The Lambert-Beer law is based on the Lambert law indicating that the logarithm of the ratio of the intensity I _{0 of the} entrance light and the intensity I of the transmitted light is proportional to the thickness d of the absorbing material. This is a combination of Beer's law representing the dependence on C, and is represented by equation (1).

In the formula (1), εdC indicates absorbance, and ε is a molar extinction coefficient, which is a substance-specific constant.

ここで、Ｃ₁は処理前の試料水の物質濃度、Ｃ₂は処理後の試料水の物質濃度である。 The decomposition rate can be obtained from the change in the concentration of the substance by equation (2).

Here, C ₁ is the substance concentration of sample water before treatment, and C ₂ is the substance concentration of sample water after treatment.

ここで、Ｓ₀は精製水の透過率（％）、Ｓ₁は処理前の試料水の透過率（％）、Ｓ₂は処理後の試料水の透過率（％）である。今回は、青色の吸光を示す波長６１０ｎｍの透過率から分解率を算出した。すなわち、求める分解率は、インディゴカルミンの青色がどれだけ分解されたかを示す。 Substituting equation (1) into equation (2) leads to a decomposition rate represented by equation (3).

Here, S ₀ is the transmittance (%) of purified water, S ₁ is the transmittance (%) of sample water before treatment, and S ₂ is the transmittance (%) of sample water after treatment. This time, the decomposition rate was calculated from the transmittance at a wavelength of 610 nm showing blue light absorption. That is, the required decomposition rate indicates how much blue of indigo carmine has been decomposed.

  Next, the specification of the pulse power generator 8 used for the measurement will be described. A BEHLIKE FET switch (HTS400-10) was used as the semiconductor switch 85, and a KENWOOD function generator (FG273) was used as the trigger oscillator 86. The capacitance of the capacitor 82 is 10.8 nF, and the resistance values of the resistors 83 and 84 are 10 kΩ. Using the pulse power generator 8 having such specifications, the charging voltage was switched to three stages of 7 kV, 10 kV and 13 kV, and the number of discharge repetitions was changed in the range of 100 pps to 1000 pps. Note that pps is a unit indicating the number of pulses per second.

  The specifications of the pulse power generator 10 used for comparison will be described. As the pulse transformer 105, a TDK pulse transformer (PC40T) having a turns ratio of 1: 6 between the primary side and the secondary side was used. The capacitance of the capacitor 102 is 940 pF, and the resistance value of the resistor 103 is 3 MΩ. Using the pulse power generator 10 having such specifications, the charging voltage was set to 24 kV, and the number of discharge repetitions was changed in the range of 25 pps to 125 pps.

  Further, the water treatment apparatus 1 was formed of a cylindrical electrode 3 in which a stainless mesh was formed into a cylindrical shape having an inner diameter of 38 mm and a length of 300 mm, and a stainless steel wire having a diameter of 0.28 mm in an acrylic container body 21 having an inner diameter of 40 mm. What provided the linear electrode 4 was used.

  While spraying 50 mL / s water droplets from the shower nozzle 7 of the water treatment apparatus 1 described above, the transmittance of the treated sample water is measured for each treatment time, and the decomposition rate is obtained using the above equation (3). It was.

  FIG. 6A shows a change in the decomposition rate with respect to the processing time at a charging voltage of 10 kV when processing is performed using the pulse power generator 8. As can be seen from FIG. 6A, the decomposition rate increases as the processing time elapses. Further, the decomposition rate is higher when the number of repetitions of discharge is larger when compared at the same processing time. This is considered to be because if the number of repetitions of the discharge is large, more ozone is generated, and the decomposition of the blue-colored structure proceeds in proportion to the number of ozone.

  On the other hand, FIG. 6B shows a change in the decomposition rate with respect to the processing time at the charging voltage of 24 kV when processing is performed using the conventional pulse power generator 10. As can be seen from FIG. 6B, the tendency similar to that of the pulse power generator 8 is shown, but the decomposition rate is not necessarily proportional to the number of repetitions of discharge.

<Comparison of discharge repetition rate and decomposition rate, discharge power and decomposition rate>
Next, regarding the pulse power generator 8, the relationship between the number of discharge repetitions and the decomposition rate and the relationship between the discharge power and the decomposition rate were determined.

First, a method for calculating the discharge power will be described. Since the discharge power is discharge energy per unit time (unit: W = J / s), after obtaining the discharge energy, the discharge power is calculated from the value. The discharge energy is calculated by integrating the product of the voltage waveform and the current waveform between the terminals 87 and 88 and then subtracting the apparent energy due to the displacement current. Specifically, the discharge energy for one pulse is obtained by the following steps.
(1) A voltage waveform and a current waveform for one pulse between the terminals 87 and 88 are measured using a high voltage probe and a Rogowski coil.
(2) The voltage waveform obtained in (1) and the current waveform are multiplied to obtain a waveform indicating power.
The energy for one pulse is calculated by integrating the power waveforms obtained in (3) and (2).
When the energy of the displacement current component is subtracted from the energy obtained in (4) and (3), discharge energy is obtained.

  Here, the reason why the energy of the displacement current component is drawn will be described. The current waveform measured between the terminals 87 and 88 is a waveform in which the current due to the discharge and the displacement current due to the capacitor component of the discharge electrode are combined. The energy of the displacement current component is the apparent energy due to the current of the capacitor component. By subtracting the energy of the displacement current component from the energy calculated in the above step (3), the energy of one pulse discharged between the terminals 87 and 88 is obtained.

  FIG. 7A shows a change in the decomposition rate with respect to the number of repetitions at a processing time of 30 seconds, and FIG. 7B shows a change in the decomposition rate with respect to the discharge power at the same time. The charging voltages 7, 10, and 13 kV are values when processed by the pulse power generator 8 of the present embodiment, and the charging voltage 24 kV is a value when processed by the conventional pulse power generator 10.

  FIG. 8A shows a change in the decomposition rate with respect to the number of repetitions at a processing time of 60 seconds, and FIG. 8B shows a change in the decomposition rate with respect to the discharge power at the same time. As in FIG. 7, the charging voltages 7, 10 and 13 kV are values when processed by the pulse power generator 8 of the present embodiment, and the charging voltage 24 kV is a value when processed by the conventional pulse power generator 10. It is.

  As can be seen from FIGS. 7A and 8A, the higher the charging voltage and the number of repetitions, the higher the decomposition rate. On the other hand, as can be seen from FIG. 7B and FIG. 8B, the lines with charging voltages of 10 kV, 13 kV, and 24 kV overlap as a single curve. From this, it can be seen that the decomposition rate does not depend on the charging voltage, the number of repetitions, and the apparatus, but on the discharge power. The line with the charge voltage of 7 kV does not overlap with the other lines, but this is considered because the discharge energy of one pulse is too small compared with other charge voltages, and the amount of generated ozone is small.

<Comparison of energy efficiency of water treatment equipment>
Through the experiments described above, it was found that the decomposition rate of organic substances depends on the discharge power. That is, it was found that even if the pulse voltage and the number of repetitions of the pulse output from the pulse power generator and the waveform of the voltage and current are different, substantially the same decomposition rate can be obtained if the discharge energy is equal. If this property is used, the energy efficiency of the water treatment apparatus adopting the pulse power generator is compared by comparing the energy transfer efficiency when the same decomposition rate is obtained for the pulse power generators of different configurations. be able to.

  As a premise for obtaining the energy efficiency of the water treatment device, the energy transfer efficiency was obtained for each of the pulse power generation device 8 and the pulse power generation device 10 having the specifications described above. Energy transfer efficiency is obtained by dividing discharge energy by charge energy. The discharge energy is calculated using the voltage waveform and the current waveform by the above-described calculation method.

ここで、Ｃはコンデンサ８２の容量（またはコンデンサ１０２の容量、以後も同様）、Ｖ₁はコンデンサ８２から電荷が放出される前のコンデンサ８２の端子間電圧、Ｖ₂はコンデンサ８２から電荷が放出された後のコンデンサ８２の端子間電圧である。 On the other hand, the charging energy is calculated by the following equation (4).

Here, C is the capacity of the capacitor 82 (or the capacity of the capacitor 102, and so on), V ₁ is the voltage across the capacitor 82 before the charge is discharged from the capacitor 82, and V ₂ is the charge discharged from the capacitor 82. This is the voltage between the terminals of the capacitor 82 after being applied.

  FIG. 9 shows the calculation result of the energy transfer efficiency. In the figure, the horizontal axis represents the number of discharge repetitions, and the vertical axis represents the energy transfer efficiency. For the pulse power generator 8, the discharge voltage was changed between 7 and 19 kV, and for the pulse power generator 10, the discharge voltage was fixed at 24 kV.

  As can be seen from FIG. 9, the energy transfer efficiency of the conventional pulse power generator 10 is almost the same. On the other hand, the pulse power generation device 8 of the present embodiment is excellent as a pulse generation source of the water treatment device because the energy transfer efficiency can be increased by increasing the charging voltage.

  The reason why the energy transfer efficiency of the pulse power generator 8 is higher than that of the pulse power generator 10 will be described. In the pulse power generator 10, when the trigger tron gap switch 104 is turned on, the electric charge from the capacitor 102 flows in the closed loop of the capacitor 102, the pulse transformer 105, and the trigger tron gap switch 104. In this case, even if the discharge at the discharge electrode stops, the charge continues to flow in the closed loop and is consumed by the triggertron gap switch 104 and the pulse transformer 105, and the corresponding charge is wasted.

  On the other hand, in the pulse power generator 8, charge flows directly from the capacitor 82 to the discharge electrode, and the semiconductor switch 85 is turned off after about 200 nS, so that wasteful charge consumption can be suppressed.

  When the discharge voltage exceeds 10 kV, the energy transfer efficiency tends to decrease as the number of repetitions increases. This is thought to be due to the fact that by-products are generated in the discharge space and the discharge is less likely to occur by increasing the number of discharge repetitions.

  Next, the energy efficiency of the water treatment apparatus was compared between the pulse power generator 8 of the present embodiment and the conventional pulse power generator 10. For each of the pulse power generation device 8 and the pulse power generation device 10, two measurement results showing substantially the same decomposition rate with respect to the same processing time were extracted from the measurement results of the decomposition rate with respect to the processing time. The results are shown in FIGS. 10 (a) and 11 (a).

  In FIG. 10A, the charging voltage of the pulse power generator 8 is 13 kV and the discharge repetition rate is 1000 pps. On the other hand, the charging voltage of the pulse power generator 10 is 24 kV and the discharge repetition rate is 125 pps. In FIG. 11A, the charging voltage of the pulse power generator 8 is 13 kV, and the number of discharge repetitions is 600 pps. On the other hand, the charging voltage of the pulse power generator 10 is 24 kV, and the number of discharge repetitions is 75 pps.

  As described above, since the decomposition rate depends on the discharge power (discharge energy), in FIGS. 10A and 11A, the discharge power (discharge energy) of the pulse power generator 8 and the pulse power generator 10 is as follows. Are almost equal.

  FIGS. 10 (b) and 11 (b) show the horizontal axis of FIGS. 10 (a) and 11 (a) converted into the charging energy for the capacitor. In the figure, the horizontal axis represents charging energy, and the vertical axis represents the decomposition rate.

  As is clear from FIG. 10B and FIG. 11B, there is a difference in charging energy with respect to the same decomposition rate, and the pulse power generator 8 has the same decomposition rate as compared with the pulse power generator 10. It can be seen that it is realized with less energy.

  Referring to the measurement results of FIG. 9 described above, when comparing the energy transfer efficiency with respect to the charging voltage and the number of discharge repetitions shown in FIG. 10A, the pulse power generator 8 is 3 than the pulse power generator 10. It can be seen that it is about% higher. Similarly, when the energy transfer efficiency is compared for the charging voltage and the number of discharge repetitions shown in FIG. 11A, it can be seen that the pulse power generator 8 is about 6% higher than the pulse power generator 10.

  From the above, even if the discharge power (discharge energy) is equal, the decomposition rate with respect to the charge energy is higher in the pulse power generation device 8 of the present embodiment, and the energy efficiency of the water treatment device is higher than the pulse power generation device 8. It can be seen that is superior to the pulse power generator 10. Therefore, by adopting the pulse power generation device 8 according to the present embodiment as a high voltage pulse generation source, a water treatment device excellent in energy efficiency can be realized.

  The application of the above-described pulse power generator 8 is not necessarily limited to a water treatment device, and can be applied to other fields such as an air purifier that process an object to be processed by plasma discharge.

  The water treatment apparatus according to the present invention can be widely used for purification of waste water containing organic matter and microorganisms, sterilization of contaminated water, and the like.

DESCRIPTION OF SYMBOLS 1 Water treatment apparatus 2 Container 3 Cylindrical electrode 4 Linear electrode 5 To-be-treated water tank 6 Pump 7 Shower nozzle 8 Power pulse generator 9 To-be-treated water tank storage box 72 Injection part 81 High voltage DC power supply 82 Capacitors 83, 84 Resistance 85 Semiconductor switch 86 Trigger oscillator

Claims (6)

A cylindrical electrode and a linear electrode disposed along the central axis of the cylindrical electrode are provided, and a pulsed high voltage is applied between both electrodes from a pulse power generator to form a discharge space. A water treatment device that oxidizes the water to be treated by passing water droplets of the water to be treated in the discharge space,
The pulse power generator is
DC power supply,
A capacitor that is charged by the current from the DC power supply;
A trigger oscillator capable of generating pulses and adjusting the number of repetitions of the pulses;
A water treatment device comprising: a semiconductor switch connected to the capacitor, and instantaneously releasing the charge charged in the capacitor when a pulse output from the trigger oscillator is input.   The water treatment apparatus according to claim 1, wherein a MOS FET is used as the semiconductor switch.   The water treatment apparatus according to claim 1, wherein the DC power supply is adjustable in voltage. DC power supply,
A capacitor that is charged by the current from the DC power supply;
A trigger oscillator capable of generating pulses and adjusting the number of repetitions of the pulses;
And a semiconductor switch that is connected to the capacitor and instantaneously releases the charge charged in the capacitor when a pulse output from the trigger oscillator is input.   5. The pulse power generator according to claim 4, wherein a MOS type FET is used as the semiconductor switch.   The pulse power generator according to claim 4, wherein the DC power supply is capable of adjusting a voltage.

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