JPS62275004A - Ozonizer - Google Patents

Abstract

PURPOSE:To miniaturize the title ozonizer and to improve the current efficiency by providing many protrusions and holes respectively on the surfaces of an anode and a cathode which are opposed to each other to form a discharge space, and impressing a narrow-width pulse high voltage while supplying a seed atom. CONSTITUTION:An oxygen-contg. gas or air is supplied from an inlet 5 into the discharge space 7 formed between the opposed anode 1 and cathode 2, ozone is generated by the discharge action, and the ozone-contg. gas is taken out from an outlet 6. Many protrusions 13 are provided on the surface of the anode 1 in the ozonizer, and many holes 3 are bored at the part of the cathode 2 facing the anode 1, and both electrodes 1 and 2 are connected to a power supply device 8 generating a high pulse voltage having <= several tens mus pulse width. The filament 10 of a seed electron generator 9 is arranged on the counter anode side of the cathode 2. An electron avalanche phenomenon is caused by electric discharge due to the seed electron 12 generated from the filament 10, and uniform and stabilized discharge is formed.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention is used for wet ozone oxidation simultaneous desulfurization and denitrification plants, sterilization of two plants, decolorization of wastewater in urine treatment equipment, etc. The present invention relates to an ozone generator, in particular, an ozone generator that is compact, has high power efficiency, and is capable of stable discharge.

[Prior art] A conventional ozone generator called a silent discharge type
As shown in the figure, a dielectric material C such as glass is placed between electrodes a and b to which a high-voltage AC voltage of several KV is applied to prevent arc discharge, and electrodes a and b are placed in order to generate a uniform silent discharge. The distance d between them was limited to 51 or less. In the figure, j is an AC power supply, `` is a raw material gas inlet, and g is a generated ozone-containing gas outlet.

[Problems to be solved by the invention] However, with the above structure, the discharge space is small, which limits the flow rate of raw air, and it is necessary to set a large electrode area to produce a certain amount of ozone. As a result, the external dimensions of the device increase. In addition, small discharges in silent discharges are effective for ozone generation, or change to arc discharges that do not contribute much to ozone generation at the end of discharge, resulting in large current consumption and low power efficiency (see curve C in Figure 4). There was an interlude.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and its gist is to form a discharge space between opposing electrodes, and to supply a In an ozone generator that generates ozone from an oxygen-containing source gas or air using a discharge action, a positive electrode is connected to the positive side of a power supply device that generates a high voltage pulse with a pulse width of several tens of microseconds or less,
A negative electrode having a large number of protrusions on the surface of the positive electrode and a large number of holes formed in a portion facing the positive electrode surface is connected to the negative side of the power supply device, and the negative electrode is connected to the opposite positive electrode side of the negative electrode. A seed electron generator is installed.

[Function] The seed electrons generated by the seed electron generator enter the discharge space and are uniform as seed electrons when an electron sag phenomenon occurs due to the discharge of a voltage pulse with a pulse width of 10 JIS or less applied to the electrode. In addition, stable discharge can be generated, and arc discharge can be suppressed. Further, fine and uniform streamers may be generated between the negative electrode and a large number of projections provided on the surface of the positive electrode opposite to the negative electrode. Furthermore, since a pulse voltage is applied to the electrodes, high voltage can be applied. Therefore, it is possible to reduce power consumption and increase the electrode spacing, thereby making it possible to downsize the device.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure and FIG. 2 show a first embodiment of the present invention.
In the figure, ■ is a positive electrode formed in a cylindrical shape and having a number of protrusions 13 with acute angle tips protruding perpendicularly to the surface on the discharge space side;
2 is a cylindrical negative electrode that is arranged concentrically within the positive electrode l and has a number of holes 3 in the portion facing the positive electrode l; 4 is an insulator; 5 is an intake port for oxygen-containing source gas or air; B is a gas outlet containing produced ozone, 7 is a discharge space, 8 is a high-voltage pulse power supply with a pulse width of several 1 lus or less, 9 is a linear filament 10 placed in the vacuum at the center of the negative electrode 2, and This is a seed electron generating device consisting of a cylindrical seed electron passing window 11 (made of aluminum foil or titanium foil) provided inside the negative electrode 2, and each electrode 1.2
The filament IO is connected to the power supply 8 as shown in the figure according to its polarity.

Next, the operation of this device will be explained. When a high voltage pulse voltage is applied to each electrode 1.2 and filament lO,
Thermion electrons 12 (hereinafter referred to as seed electrons) are emitted from the heated filament IO, and these seed electrons 12 penetrate the seed electron passage window 11 and are emitted into the discharge space 7 through the hole 3 (as indicated by the arrow h).

At this time, due to the high voltage pulse voltage, a discharge occurs between the negative electrode 2 and the protrusion 13 on the surface of the positive electrode 1,
The seed electron 12 collides with the source gas (oxygen or air), causing the "electron sag" phenomenon described in the following equation, and the number of seed electrons rapidly increases like a chain reaction (see Figure 2).
.

(1) In the case of raw material gas or oxygen gas e + 02-e '+ e + 02+ Formula (1)
(2) If the raw material gas is air, in addition to equation (1), e +N
2-e + e + N2 (2) Then, this dramatically increased amount of seed electrons 12 collides with the oxygen gas o2 supplied into the discharge space 7 and generates excited ionized radicals, resulting in the following equation: Ozone 03 is generated according to the following.

02+e-0+O+e Formula (3) 0+02-0
3 Equation (4) The power efficiency regarding ozone 03 generated by the above action is shown by curve a in FIG.

A second embodiment of the invention is shown in FIG. In this example, the electrodes 1a and 2a are formed into plate shapes and arranged in parallel to each other, the seed electron generator 9a is arranged on the upper surface of the negative electrode 2a, and the filament lOa is formed into a plate shape (or a plurality of filaments). Other than that, there is no difference from the first embodiment.

It should be noted that the present invention is not limited to the above-mentioned embodiments. For example, an isotope or electron beam generator may be applied to the seed electron generator, or an ultraviolet or
It goes without saying that various modifications may be made without departing from the gist of the invention, such as the use of a photoionized species electron generator using a wire or the like.

Note that a cold cathode may be used instead of the filament, and the protrusion may be a needle implanted therein. Furthermore, although it is preferable that the tip of the protrusion has an acute angle, it is of course possible to see a significant improvement even if the tip is not acute (see the curve in Figure 4).
.

[Effects of the Invention] As described above, the present invention exhibits the following excellent effects.

Q) Since the seed electron generator is used to generate an electron sag phenomenon in the discharge space, a stable and uniform discharge can be formed with low quenching power.

(n) Since a large number of protrusions having acute-angled tips are protruded on the surface of the positive electrode opposite to the negative electrode, the discharge path is ensured, and the generated streamers can be made finer and more uniform.

(g) As a result of item (1), arc discharge can be suppressed and power efficiency can be improved.

(g) Since a pulse voltage is repeatedly and intermittently applied to the discharge electrode, it is possible to apply high voltage, and the gap between the electrodes can be expanded (from the conventional 5fflff1 or less to 50 to 1oonon), and the device can be made smaller. can be achieved.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the present invention, FIG. 1 is a cutaway side view, FIG. 2 is an explanatory diagram of the electronic sag phenomenon,
FIG. 3 is a cutaway side view showing the second embodiment of the present invention;
The figure is a diagram showing the relationship between input power ratio and power efficiency, and FIG. 5 is an explanatory diagram of a conventional device. In the figure, 1. Ia is a positive electrode, 2 and 2a are negative electrodes, 3 is a hole, 5 is a source gas inlet, 6 is a gas outlet containing generated ozone, 7 is a discharge space, 8 is a power supply device, 9.9a is a seed electron generator, 10 and 10a are filaments, 12 is a seed electron, and L3 is a protrusion.

Claims (1)

[Claims] 1) In an ozone generator that forms a discharge space between opposing electrodes and generates ozone from an oxygen-containing raw material gas or air supplied into the discharge space by using a discharge action, a pulse width of several 10 μs or less is used. A positive electrode is connected to the positive side of a power supply device that generates high voltage pulses, and a negative electrode is provided with a large number of protrusions on the surface of the positive electrode and a large number of holes in a portion facing the positive electrode surface. An ozone generator, characterized in that it is connected to the negative side of a power supply device, and a seed electron generator is disposed on the opposite side of the negative electrode to the positive electrode.