JPH08273551A - Ionizing method - Google Patents

Abstract

PURPOSE: To carry out ionization efficiently by controlling the supplied discharge power in proportion to the amount of supply of raw gas. CONSTITUTION: Desired raw gas to be ionized is introduced into a discharge reaction vessel 1 through a gas inflow pipe 1a, is ionized by means of discharging between rotating electrodes 2a to 2c and the interior wall of the vessel 1, and is taken out through an outflow pipe 1b. High voltages for discharging are supplied from a high-voltage power circuit 4 via brushes 44a to 44c in contact with shafts 21a to 21c to the electrodes 2a to 2c arranged in a number of stages. The shafts 21a to 21c are secured to one another by connectors 22a to 22b each made of an insulating material, and are integrally rotated at a constant speed by a motor 3. The raw gas is supplied from a blower 51 to the vessel 1 via a pressure control valve 52 and an orifice 53. The discharge power supplied is controlled in proportion to the amount of supply of the raw gas. Adjustment for increasing or decreasing the discharge power is carried out by holding constant the frequency at which a pulse generator 47 oscillates and controlling the ratio of the rise time to the interrupting time of pulses according to the flow rate of the raw gas which is detected by a flow rate transmitter 54.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to improvements in ionization processes.

[0002]

2. Description of the Related Art Ion gas such as ozone is used in various fields such as disinfection and bleaching, surface treatment gas, chemical reaction gas, etc., and the most general production method is the desired gas. In this method, a gas discharge is performed.

In the case of ionization by such gas discharge, it is known that the generation and decomposition of ions are both proportional to the discharge power, and the reaction efficiency is expressed by the function of the volume of the raw material gas and the power. If the discharge power is improper,
There are problems that the electrode becomes hot and ion recombination occurs, resulting in a significant decrease in ionization efficiency.

[0004]

The present invention has been made to solve the above problems, and an object of the present invention is to provide a highly efficient ionization method.

[0005]

The above object can be achieved by controlling the discharge power to be supplied in proportion to the supply amount of the raw material gas.

In this case, the discharge generating electrodes are provided in multiple stages,
It is recommended that these electrodes be connected to a high voltage power supply in a rotating manner or with a phase difference. Also,
It is recommended to generate a dynamic plasma in the discharge.

[0007]

With the above-mentioned constitution, recombination of ions does not occur, the reaction is carried out at a low temperature, and the gas is efficiently ionized and ionized at a constant reaction rate.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 1 is an explanatory view showing the outline of an apparatus for carrying out the ionization method according to the present invention, FIG. 2 is an explanatory view showing the structure of the rotary electrode for discharge, and FIG. 3 shows the shape of one rotary electrode. A plan view and FIG. 4 are diagrams showing a discharge pulse voltage.

In the figure, 1 is a discharge reaction tank, 1a is a gas inlet pipe, 1b is a gas outlet pipe, 2a, 2b and 2c are rotary electrodes for discharge, and 20 (see FIG. 2) is one rotary electrode 2a-1. The protrusions, 21a, 21b and 21c, formed on the outer periphery of the shaft are insulated from each other and rotate together with the shaft.
Is a driving device such as a motor for rotating the shaft, 4 is a power supply circuit for supplying a high voltage to the rotating electrode, and 5 is a device for supplying a raw material gas into the discharge reaction tank 1.

As shown in FIG. 3, the rotary electrode 2a is formed by stacking a plurality of metal plates each having a large number of protrusions 20 formed on the outer periphery thereof with a predetermined gap therebetween, and mounting the metal plates on the shaft 21a. The rotating electrodes 2b and 2c have the same structure.

The power supply circuit 4 includes a converter 41, switching elements 42a to 42c, and step-up transformers 43a to 43.
c, brushes 44a to 44c, thyristors 45a to 45
c, a ring counter 46, and a pulse generator 47, and the source gas supply device 5 includes a blower 51,
It is composed of a pressure control valve 52, an orifice 53, a flow rate transmitter 54 and the like.

Thus, the gas inflow pipe 1 is provided in the discharge reaction tank 1.
The desired source gas to be ionized is introduced through a,
It is ionized by the discharge generated between the rotating electrodes 2a to 2c and the inner wall of the discharge reaction tank 1 and taken out through the outflow pipe 1b.

The rotating electrodes 2a to 2c provided in multiple stages are
A high voltage for discharging is supplied from the power supply circuit 4 described later through the brushes 44a to 44c that are in contact with the respective shafts 21a to 21c. The shafts 21a, 21b and 21c are fixed to each other by connectors 22a and 22b made of an insulating material such as ceramic (see FIG. 2) and are rotated together by a motor 3 at a constant speed. Reference numerals 23a and 23b are bearings. It is desirable that the surfaces of the shafts 21a, 21b, and 21c other than the portions in contact with the brushes be coated with an insulating material such as Teflon (registered trademark).

The raw material gas is supplied from the blower 51 to the pressure control valve 5
2. It is supplied to the discharge reaction tank 1 through the orifice 53.
The flow rate transmitter 54 detects the flow rate of the raw material gas passing through the orifice 53, and the duty factor of the pulse oscillated by the pulse generator 47 described later is changed and controlled so as to be proportional to the flow rate.

In the discharging high-voltage power supply circuit 4, the direct current supplied from the converter 41 is intermittently pulsed at a high frequency by the switching elements 42a to 42c, and the direct current is supplied via the step-up transformers 43a to 43c. It is supplied to the brushes 44a to 44c. The ON / OFF control of the switching elements 42a to 42c is performed by the pulse signal generated by the pulse generator 47, and the output pulse from the pulse generator 47 is the output signal of the ring counter 46 operating at a lower frequency than this. Thyristor 45 turned on / off by
The brushes 44a to 44c are intermittently connected by a to 45c and are alternately supplied to the brushes 44a to 44c in a ring-like manner.

That is, the frequency of the pulse oscillated by the pulse generator 47 is set to 1 to 2 MHz, while the frequency of the ring counter 46 is set to 1 to 50 KHz, and the thyristors 45a to 45c rotate in the range of 1 to 50.
It is designed to be turned on / off at the frequency of KHz.
Therefore, when the thyristor 45a is turned on and becomes conductive, the pulse from the pulse generator 47 is supplied to the switching element 42a, and the switching element 42a is turned on by one.
ON / OFF control is performed at a high frequency of 2 MHz, whereby the rotating electrode 2a causes discharge and ionization. Next, when the thyristor 45a is turned off and the thyristor 45b is turned on and becomes conductive, the pulse from the pulse generator 47 is supplied to the switching element 42b, and the switching element 42b is turned on / off at a high frequency of 1 to 2 MHz. Discharge and ionization are performed by the rotating electrode 2b. Similarly, the switching element 4
2c, 42a, 42b and 42c are electrically connected to each other in a rotating manner, and the rotating electrodes 2c, 2a, 2b and 2c are electrically discharged and ionized in a rotating manner. It is recommended to adjust the voltage, pulse frequency, etc. so that this discharge causes an anode corona.

Thus, in the present invention, the discharge power to be supplied is controlled in proportion to the supply amount of the raw material gas. The increase / decrease adjustment of the discharge power is oscillated from the pulse generator 47, for example. This can be done by changing the duty factor of the pulse. That is, as shown in FIG. 4, the pulse rise time τ is maintained while the frequency (wavelength) of the pulse oscillated by the pulse generator 47 is kept constant.
The ratio (duty factor) of _on to cutoff time τ _off is
By changing and controlling the flow rate of the raw material gas detected by the flow rate transmitter 54, the switching element 42a
By increasing or decreasing the average conduction time, etc., the discharge power is increased or decreased. Of course, the increase / decrease control of the discharge power can be performed by other means. For example, the step-up transformers 43a to 43c are variable transformers,
The discharge voltage may be changed according to the flow rate of the source gas.

Next, an experimental example of ionization by the method of the present invention will be shown. The yield of ozone was 180 g / KWH when oxygen was used as a source gas, a 10-45 KV power source was used, and discharge was performed at an average flow rate of 1.6 l / min.
Practical peak voltage is 10 KV, τ _on = 20 μs, τ _off =
The best efficiency was obtained at 80 μs. 13.5 liters / mi
At the average flow rate of n, τ _on = 1100 μs, τ _off = 440 μ
The ozone yield was 110 g / KWH. Ozone water could be obtained when mixed with water of 10 ⁶ Ωcm by the ejector. The ozone water had a maximum ozone concentration of 8 liters / min and 4.5 g / m ³ .
The temperature rise of the electrode was 25 ° C.

If impurities are mixed in the raw material gas, spark discharge is likely to occur, and therefore it may be necessary to protect the electrodes with an insulating coating. In that case, some efficiency must be sacrificed.

[0020]

According to the method of the present invention having the above-mentioned constitution, recombination of ions does not occur, the reaction is carried out at a low temperature, and the gas is efficiently ionized and ionized at a constant reaction rate. It is done. The present invention is not limited to the above embodiments. For example, although the electrodes 2a to 2c are rotated in the above embodiments, the method of the present invention can be carried out even if the electrodes do not rotate. It is possible and, therefore, within the scope of its object, the invention embraces all modifications which can be easily conceived by a person skilled in the art from the above description.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an outline of an apparatus for carrying out an ionization method according to the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a rotary electrode for discharge.

FIG. 3 is a plan view showing the shape of one rotating electrode.

FIG. 4 is a diagram showing a discharge pulse voltage.

[Explanation of symbols]

 1 Discharge reaction tank 1a Gas inflow pipe 1b Gas outflow pipe 2a to 2c Rotating electrode 2a-1 One electrode 20 Projection 21a to 21c Shaft 22a, 22b Insulation connector 23a, 23b Bearing 3 Drive device 4 High voltage power circuit 41 Converter 42a 〜42c Switching element 43a 〜43c Step-up transformer 44a 〜44c Brush 45a 〜45c Thyristor 46 Ring counter 47 Pulse generator 5 Raw material gas supply device 51 Blower 52 Pressure control valve 53 Orifice 54 Flow transmitter

Claims (3)

[Claims] 1. A method for producing a discharge in a source gas to ionize a part of the gas, wherein the discharge power supplied is controlled in proportion to the amount of the source gas supplied. 2. The ionization method according to claim 1, wherein the discharge-generating electrodes are provided in multiple stages, and these electrodes are connected to a high-voltage power supply in a ringing manner or with a phase difference. 3. The ionization method according to claim 1, wherein a dynamic plasma is generated.