JPH10216558A - Pulse charged gas treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive a low electric power consumption while stable gas treating capacity is maintained without depending on fluctuation in a water content concentration in treating gas by a method wherein the water content concentration is estimated based on detection values of a peak voltage value and a peak current value when high tension pulse is applied, and the high tension pulse is controlled. SOLUTION: A pulse charged gas treating device has a gas treating part 1 wherein dust, nitrogen oxides, dioxin, etc., in gas are removed by generating plasma with high tension pulse charge, and high tension pulse from a pulse power source part 2 is applied thereto. In order to control variably a frequency of an output pulse of the pulse power source part 2, a data processing system 3 containing a frequency variably controlling part 4 is provided. The system 3 retrieves I-V characteristic data of each gas water content concentration in an I-V characteristic memory part 7 with a water content concentration estimation part 8 based on detection values of a peak voltage value and a peak current value when the high tension pulse is applied, estimates a water content concentration of the treating gas, and controls the high tension pulse.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse charged gas processing apparatus for generating plasma by high voltage pulse charging to remove dust, harmful gas and the like in a gas.

[0002]

2. Description of the Related Art A conventional pulse-charged gas processing apparatus of this type includes a gas processing section for generating plasma by high-voltage pulse charging to remove dust, harmful gas, and the like in a gas, and a high-pressure gas processing section. And a pulse power supply unit for applying a voltage pulse. As shown in FIG. 2, the IV characteristics of the peak voltage value and the peak current value when the high voltage pulse is applied to the processing gas are different from those in the processing gas. There is a close relationship with the water concentration that represents the ratio of the amount of water, the lower the water concentration is, the larger the peak current flows at the lower peak voltage, and the higher the water concentration is at the same peak voltage value, the lower the peak current value is. Has characteristics. The water concentration of the processing gas is approximately 1
It varies in the range of 0% to 30%. In the conventional pulse charged gas processing apparatus, there is no special technique for controlling the high-voltage pulse applied to the processing gas in response to the fluctuation of the water concentration of the processing gas. The voltage of the high voltage pulse applied when the moisture concentration fluctuates has been manually changed.

[0003]

However, in the conventional pulse charged gas processing apparatus described above, the voltage of the high-voltage pulse charged into the processing gas is manually changed by separately observing the moisture concentration of the processing gas. In addition, it was difficult to immediately respond to the fluctuation of the water concentration, and it was difficult to keep the energy injected into the processing gas constant. Experience has shown that the performance of a gas processing system improves in proportion to the amount of energy injected into the processing gas.In a conventional pulsed charged gas processing apparatus, the injection energy is reduced by the fluctuation of the water concentration. Therefore, it was difficult to keep the gas processing performance constant.

For example, when the moisture concentration increases during pulse charging at a constant voltage and frequency, the conventional method reduces the average injection energy into the processing gas, and the average injection energy decreases immediately. However, it has been difficult to maintain a predetermined gas processing capacity accurately and constant.

If the water concentration decreases and the average energy injected into the processing gas increases beyond the energy required for the amount of gas to be processed, the energy that is not consumed in the gas processing is wasted. In addition, there has been a problem that the gas processing efficiency is reduced and power saving cannot be sufficiently achieved.

Further, conventionally, when the applied voltage is manually corrected when the water concentration fluctuates, the fluctuation range of the temperature of the processing gas is not so large.
The effect on the characteristics is small compared to the case where the moisture concentration fluctuates, and temperature compensation was not particularly considered.For example, for the purpose of removing nitrogen oxides and dioxins,
In particular, when applied to pollution control-related devices or the like that require high-precision processing, it is necessary to further increase the processing effect by reflecting the change in the IV characteristics with respect to a temperature change.

An object of the present invention is to solve the above-mentioned problems,
Provide a pulse charged gas processing apparatus that can maintain a stable gas processing capacity irrespective of fluctuations in the moisture concentration in the processing gas and achieve low power consumption, and further improve the performance of the gas processing performance. It is in.

[0008]

A first characteristic configuration of the pulse charged gas processing apparatus according to the present invention for achieving this object is as described in claim 1 of the claims.
A gas processing unit that generates plasma by high-voltage pulse charging to remove dust and harmful gases in the gas, a pulse power supply unit that applies a high-voltage pulse to the gas processing unit, and a gas processing unit that is applied to the gas processing unit. An IV characteristic storage unit for storing an IV characteristic of a peak voltage value and a peak current value of the high voltage pulse for each attribute of a processing gas; and a peak voltage value of the high voltage pulse applied to the gas processing unit. And a current / voltage detecting unit for detecting a peak current value, and the I-current based on the peak voltage value and the peak current value detected by the current / voltage detecting unit.
A water concentration estimating unit for estimating the water concentration of the processing gas by retrieving at least the IV characteristic data stored in advance in the V characteristic storage unit for each of the water concentrations of the processing gas.

A second characteristic configuration according to the present invention is a temperature sensor for detecting a processing gas temperature of the gas processing section in addition to the first characteristic configuration as described in claim 2 of the claims. Wherein the moisture concentration estimating unit stores the moisture of the processing gas in the IV characteristic storage unit based on the temperature detected by the temperature sensor and the peak voltage value and the peak current value detected by the current / voltage detecting unit. I stored in advance for each concentration and temperature
-V characteristic data is searched to estimate the moisture concentration of the processing gas.

[0010] The third characteristic configuration is, as described in claim 3 of the claims, in addition to the above-mentioned first or second characteristic configuration, the pulse power supply unit is connected to the gas processing unit. Frequency variable control for variably controlling the frequency of the output pulse of the pulse power supply unit according to the moisture concentration of the processing gas estimated by the moisture concentration estimating unit so as to maintain the average value of the injected energy to be maintained at a predetermined value. It is in the point that a part is provided.

According to a fourth feature configuration, as described in claim 4 of the claims, in addition to the third feature configuration described above, the frequency variable control unit controls the water concentration and the frequency. Is based on a predetermined formula that has a positive correlation with
The point is that the optimum frequency corresponding to the moisture concentration is calculated and the variable control of the frequency is executed.

The operation and effect will be described below. According to the first characteristic configuration, in order to perform a predetermined gas processing, when applying a high-voltage pulse of a predetermined frequency and a predetermined voltage from the pulse power supply unit to the gas processing unit,
By detecting the peak voltage value and the peak current value when the high voltage pulse is applied by the current / voltage detection unit in advance or at regular time intervals, the water content is determined based on the detected peak voltage value and peak current value. The density estimating unit is configured to use the IV
It is possible to estimate the moisture concentration of the processing gas by searching the IV characteristic data for each moisture concentration of the processing gas previously stored in the characteristic storage unit.

If the moisture concentration is expected to fluctuate frequently, the interval between the detection of the peak voltage value and the peak current value by the current / voltage detection unit may be shortened in accordance with the expected fluctuation situation. Adjust it.

Here, the attribute in the IV characteristic stored for each attribute of the processing gas in the IV characteristic storage unit is the processing gas whose change in the attribute value affects the IV characteristic. For example, as described above, the main attributes are the moisture concentration and the temperature. In the case of this characteristic configuration, the moisture concentration that has the greatest effect on the IV characteristics is used as its attribute.

Therefore, according to this characteristic configuration, by estimating the water concentration of the processing gas in the gas processing section, the fluctuation of the water concentration can be immediately detected, and the control of the high voltage pulse can be performed. Since the process can be performed by following the fluctuation of the moisture concentration, it is possible to control to keep the amount of energy injected into the processing gas constant, and as a result, the processing capability of the predetermined gas processing can be maintained with high accuracy. In addition, since the amount of injected energy is not unnecessarily increased, the power consumption of the device can be reduced.

Further, since the moisture concentration is obtained by a kind of arithmetic processing of estimation, there is no need to provide a humidity sensor or the like in the gas processing unit to separately physically detect the moisture concentration. It is possible to avoid a decrease in the reliability of the entire control system and an increase in manufacturing cost due to the provision in the gas processing section under severe conditions.

According to the second characteristic configuration, the temperature detected by the temperature sensor and the peak voltage value detected by the current / voltage detection unit are changed even when the processing gas temperature fluctuates as well as the water concentration fluctuation. The water concentration estimating unit can accurately estimate the water concentration of the processing gas based on the peak current value.

Therefore, irrespective of the fluctuation of the moisture concentration, even if the peak current value of the high voltage pulse changes due to the fluctuation of the processing gas temperature and the amount of electric power charged for each applied pulse changes, It is possible to keep the average injection energy amount related to the gas processing unit constant.

As a result, even if the water concentration and the temperature of the processing gas fluctuate, the average amount of energy injected into the gas processing section can be kept constant, so that the processing capacity of the predetermined gas processing is kept constant. Can be executed with higher precision,
Further, the power consumption of the device can be reduced.

According to the third characteristic configuration, even if the peak current value of the high-voltage pulse changes due to the fluctuation of the water concentration and the amount of electric power charged for each applied pulse changes, the gas processing unit can be operated. The frequency of the high voltage pulse to be applied can be automatically adjusted to an appropriate value according to the moisture concentration of the processing gas, and as a result, the gas is automatically injected into the gas processing unit regardless of the moisture concentration and the temperature of the processing gas. The average amount of energy can be kept constant.

In the pulse power supply section, the frequency can be changed by adjusting the on / off control timing of the switching element related to the pulse generation. However, the output voltage can be changed by the pulse power supply section. In order to perform the operation without changing the circuit constants of the circuit components or the circuit configuration itself, the output voltage of the DC voltage power supply provided in the pulse power supply unit must be variable, and a constant voltage power supply cannot be used. It should be noted that this may cause the cost to rise.

Further, according to the fourth characteristic configuration, it is possible to easily maintain the average value of the energy injected from the pulse power supply unit into the gas processing unit at a constant value. That is, as described above, the peak voltage value and the peak current value when a high voltage pulse is
The -V characteristic is closely related to the moisture concentration in the processing gas,
The lower the water concentration is, the larger the peak current flows at the lower peak voltage and the injection energy increases. When the water concentration is higher at the same peak voltage value, the peak current value decreases, and the injection energy also decreases. Therefore, by setting the calculation formula so that the frequency calculated by the calculation formula in advance and the power per pulse derived from the IV characteristics and the load characteristics are proportional to each other. When the moisture concentration is low, a high-frequency pulse of a low frequency is output from the pulse power supply unit. Conversely, when the moisture concentration is high, a high-voltage pulse of a high frequency is output from the pulse power supply unit. The average amount of energy injected automatically into the gas processing section can be kept constant irrespective of the moisture concentration and temperature of the processing gas.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a pulse charged gas processing apparatus according to the present invention (hereinafter, referred to as the present apparatus)
A gas processing unit 1 for generating plasma by high-voltage pulse charging to remove dust and harmful gases such as nitrogen oxides and dioxins in the gas; and a pulse power supply for applying a high-voltage pulse to the gas processing unit 1. It has a configuration including a unit 2 and a data processing system 3 having a built-in frequency variable control unit 4 for variably controlling the frequency of the output pulse of the pulse power supply unit 2.

The input terminal 10 of the gas processing unit 1 and the output terminal 2a of the pulse power supply unit 2 are electrically connected after being subjected to necessary insulation processing. Further, a temperature sensor 11 for detecting a processing gas temperature is provided in the gas processing unit 1, and an output signal thereof is transmitted to the data processing system 3. In addition, the gas processing unit 1
A peak voltage value and a peak current value of a high-voltage pulse output from the pulse power supply unit 2 to the gas processing unit 1 in the middle of a conducting wire 20 connected between the input terminal 10 and the output terminal of the pulse power supply unit 2. And a voltage / current probe 5 forming a current / voltage detecting unit for detecting the peak voltage and the peak current value, the output signal 5a of which is input to a synchroscope 6 and amplified and signal-processed by the synchroscope 6 Data is input to the data processing system 3.

The data processing system 3 includes, in addition to the frequency variable control unit 4, a peak voltage value and a peak current value of the high voltage pulse applied to the gas processing unit 1.
I-V in which V characteristics are stored for each moisture concentration and temperature of the processing gas
Based on the characteristic storage unit 7 and the temperature detected by the temperature sensor 11 and the peak voltage value and the peak current value detected by the voltage / current probe 5 and amplified and signal-processed by the synchroscope 6, the I-V I- measured in advance for each moisture concentration and temperature of the processing gas stored in the characteristic storage unit 7
A moisture concentration estimating unit 8 for retrieving V characteristic data and estimating the moisture concentration of the processing gas, wherein the frequency variable control unit 4 The water concentration estimating unit 8 calculates an optimum frequency corresponding to the water concentration of the processing gas estimated by the water concentration estimating unit 8 so as to maintain the average value of the energy at a constant value. By outputting the synchronization pulse 4a, the frequency of the output pulse of the pulse power supply unit 2 is variably controlled.

The data processing system 3 including the IV characteristic storage unit 7, the water concentration estimating unit 8, and the frequency variable control unit 4 is, specifically, a microcomputer, a semiconductor memory, It is composed of a storage medium and necessary interface circuits.

As shown in FIG. 3, the processing gas is supplied to the duct 18.
a to the discharge chamber 12a,
Proceeds along the longitudinal direction, and is collected in the discharge chamber 12a, denitrated by an oxidation-reduction reaction in the case of nitrogen oxide, and decomposed in the case of dioxin, and is processed from the duct 18b to the next processing apparatus. Discharged. As shown in FIG. 3, a plurality of the linear discharge electrodes 13 are formed in a rectangular shape and are extended between two opposing upper and lower sides of a conductive discharge electrode frame 13a, and the discharge electrodes 13 are short-circuited to each other. And at the same potential. Further, as shown in FIG. 4, three discharge electrode frames 13a and four ground electrodes 14
In the discharge chamber 12a, the discharge electrode frame 13a is sandwiched by the ground electrode 14 at a fixed distance, and the longitudinal direction of each of the discharge electrode frames 13a is the direction in which the exhaust gas flows in the discharge chamber 12a (in FIG. 4,
(Vertical direction on the paper). The three discharge electrode frames 13a are short-circuited in the discharge chamber 12a. As shown in FIG. 3, both ends of the upper portion of the discharge electrode frame 13a are supported by the support insulator 17 from the ceiling of the discharge chamber wall 12c so as to be insulated from the discharge chamber wall 12c. .

As shown in FIGS. 3 and 4, the output terminal 2a of the pulse power supply unit 2 is electrically connected to the three discharge electrode frames 13a in the discharge chamber 12a by the conducting wire 20. The conductive wire 20 is wired through one through insulator 16 provided on the ceiling of the discharge chamber wall 12c.

The function and operation of each part of the data processing system 3 will be described below. The IV characteristic of the peak voltage value and the peak current value of the high-voltage pulse stored in the IV characteristic storage unit 7 can be used to determine various moisture concentrations and temperatures before the full-scale operation of the apparatus of the present invention. A processing gas is supplied to the discharge chamber 12a, and a high voltage pulse is applied from the pulse power supply unit 2 to the discharge electrode 13 for each processing gas, and the instantaneous data of the voltage peak value and the current peak value at that time is converted to the voltage. After being detected by the current probe 5 and amplified and signal-processed by the synchroscope 6, the data is digitized together with the moisture concentration and temperature data of the processing gas when the high-voltage pulse is applied, and the IV characteristic storage unit 7 is stored. It is stored in a predetermined area of a nonvolatile memory to be constituted.

The water concentration estimating unit 8 stores the IV characteristic data input from the synchroscope 6 and the IV characteristic storage unit 7 corresponding to the processing gas temperature input from the temperature sensor 11. The extracted IV characteristic data is compared with the extracted IV characteristic data to extract the moisture concentration of the IV characteristic data that matches or approximates the extracted IV characteristic data, and performs an interpolation process as necessary to estimate the moisture concentration.

From the optimum average injection energy determined from the gas processing amount of the gas processing unit 1, specific IV characteristic data, and the amount of power per pulse derived from the load characteristics of the discharge electrode 13. The optimal frequency to be calculated backward is uniquely determined if the moisture concentration and temperature of the processing gas are known.
Based on the IV characteristic data, a calculation formula for calculating an optimum frequency using the moisture concentration and the temperature of the processing gas as variables is created in advance and stored in a predetermined area of the nonvolatile memory of the frequency variable control unit 4. Keep it.

The variable frequency control section 4 calculates the optimum frequency by substituting the processing gas temperature input from the temperature sensor 11 and the water concentration of the processing gas estimated by the water concentration estimating section 8 into the above-mentioned equation. , And outputs a synchronization pulse 4 a having the same frequency as the optimum frequency to the pulse power supply unit 2. The pulse power supply unit 2 can output a high-voltage pulse at the same optimal frequency by controlling the timing of the internal switching element at the rising or falling edge of the synchronization pulse 4a. Note that the calculation formula may be a plurality of formulas prepared using the processing gas temperature as a parameter.

The gas treatment in the discharge chamber 12a is performed by corona discharge between the discharge electrode 13 and the ground electrode 14. The corona discharge is controlled so that the output voltage of the pulse power supply unit 2 starts around 50 kV and does not reach the arc discharge region.

Hereinafter, another embodiment will be described. (1) In the present embodiment, the gas processing unit 1 having a large maximum gas processing amount is assumed. However, the configuration and the electrical specifications of the pulse power supply unit 2 can be appropriately changed according to the specifications of the gas processing unit 1. Is not limited to this embodiment,
A plurality of pulse power supplies may be used. When the pulse power supply unit 2 is constituted by a plurality of pulse power supply devices, the output pulses of the plurality of pulse power supplies of the pulse power supply unit 2 are controlled so as to have the same frequency and to be synchronized with each other. That is, the same synchronous pulse 4 is applied to each pulse power supply device.
A is configured to be input. Although the actual pulse waveform of the pulse power supply unit 2 causes overshoot or ringing due to the stray inductance component of the conducting wire 20 or the like, the type of the pulse power supply unit 2 is unified between the pulse power supply units, The output terminals of the pulse power supply unit 2 are connected by connecting the respective output terminals of the pulse power supply device in parallel.
It is preferable that the output pulses are synchronized at the same frequency as described above, so that a voltage having the same pulse waveform is applied to each of the discharge electrodes 13.

(2) In the present embodiment, the IV characteristic storage unit 7 stores the IV characteristics of the peak voltage value and the peak current value of the high voltage pulse for each moisture concentration and temperature of the processing gas. However, only the above-mentioned IV characteristic at a predetermined standard processing gas temperature may be stored for each moisture concentration. In this case, when the processing gas temperature greatly fluctuates with respect to the standard processing gas temperature, the water concentration estimated by the water concentration estimating unit 8 is corrected based on the temperature detected by the temperature sensor 11. Is also a preferred embodiment. In addition, when the processing gas temperature does not largely fluctuate with respect to the standard processing gas temperature and correction of the temperature fluctuation is not necessary, the frequency variable control unit 4 is injected from the pulse power supply unit 2 into the gas processing unit 1. The moisture concentration estimating unit 8 uses the moisture concentration of the processing gas estimated by the moisture concentration estimating unit 8 without correction so as to maintain the average value of the injected energy at a constant value, and calculates an optimum frequency corresponding to the moisture concentration. A configuration may be adopted in which the synchronization pulse 4a is output to the pulse power supply unit 2 based on the optimum frequency, and the frequency of the output pulse of the pulse power supply unit 2 is variably controlled.

(3) The structure of the gas processing section 1 is not limited to this embodiment. The number and shape of the discharge electrode 13, the discharge electrode frame 13a, the ground electrode 14, the conductor 20, the penetrating insulator 16, and the supporting insulator 17 are not limited to the present embodiment.

(4) In this embodiment, the synchroscope 6 performs the signal processing on the peak voltage value and the peak current value detected by the voltage / current probe 5 so that the data processing system 3 can process the signal. Although it functions as a part of the current / voltage detection unit for the system 3, the same processing may be performed in the data processing system 3.

[0038]

As described above, according to the present invention,
It has become possible to provide a pulse-charged gas processing apparatus capable of maintaining a stable gas processing ability with high accuracy regardless of fluctuations in the moisture concentration in the processing gas and the processing gas temperature and achieving low power consumption.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a pulse charged gas processing apparatus according to the present invention.

FIG. 2 is an IV characteristic diagram of a peak voltage value and a peak current value of a high voltage pulse.

FIG. 3 shows the installation state of the discharge electrodes in the discharge chamber in a vertical cross section of the discharge chamber including the discharge electrodes along the longitudinal direction of the gas processing unit of the pulse charged gas processing apparatus according to the present invention, and a pulse power supply provided outside the discharge chamber. Schematic configuration diagram showing parts

FIG. 4 is a schematic configuration diagram of a gas processing unit of the pulse charged gas processing apparatus according to the present invention in a vertical section connecting AA in FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 gas processing unit 2 pulse power supply unit 3 data processing system 4 variable frequency control unit 4a synchronization pulse 5 current / voltage detection unit 5a output signal 6 synchroscope 7 IV characteristic storage unit 8 moisture concentration estimation unit 10 input terminal 11 temperature sensor 20 Conductor

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroki Fujihira 1-2-1, Shinhama, Arai-machi, Takasago-shi, Hyogo Inside Takuma Central Research Laboratory Co., Ltd. (72) Inventor Kaichi Sakakibara 55

Claims (4)

[Claims] A gas processing unit for generating plasma by high-voltage pulse charging to remove dust, harmful gas, and the like in the gas; a pulse power supply unit for applying a high-voltage pulse to the gas processing unit; An IV characteristic storage unit for storing the IV characteristics of the peak voltage value and the peak current value of the high voltage pulse applied to the processing unit for each attribute of the processing gas; and the high voltage applied to the gas processing unit. A current-voltage detection unit that detects a peak voltage value and a peak current value of a pulse; and based on the peak voltage value and the peak current value detected by the current-voltage detection unit, at least the processing gas is stored in the IV characteristic storage unit. A pulse charged gas processing apparatus comprising: a water concentration estimating unit that searches for IV characteristic data stored in advance for each water concentration and estimates the water concentration of the processing gas. 2. A temperature sensor for detecting a processing gas temperature of the gas processing unit, wherein the moisture concentration estimating unit detects a temperature detected by the temperature sensor, a peak voltage value detected by the current voltage detecting unit, and a peak current. Based on the value, the IV characteristic data is pre-stored in the IV characteristic storage unit for each of the moisture concentration of the processing gas and the temperature, and the moisture concentration of the processing gas is estimated. The pulse charged gas processing apparatus according to claim 1. 3. The method according to claim 2, wherein the average value of the energy injected from the pulse power supply unit into the gas processing unit is maintained at a predetermined value in accordance with the water concentration of the processing gas estimated by the water concentration estimating unit. The pulse charged gas processing apparatus according to claim 1 or 2, further comprising a frequency variable control unit that variably controls a frequency of an output pulse of the pulse power supply unit. 4. The frequency variable control unit calculates an optimum frequency corresponding to the moisture concentration based on a predetermined calculation formula in which the moisture concentration and the frequency have a positive correlation, and The pulse charged gas processing apparatus according to claim 3, wherein variable control is performed.