KR20060124864A - Underwater plasma discharging apparatus and discharging method using it - Google Patents

Abstract

An underwater plasma discharging equipment that capable of smoothly utilizing in water purification active radicals generated accordingly by stably maintaining plasma discharge in the water, and an underwater discharging method using the same are provided. An underwater plasma discharging equipment comprises: at least one pair of electrodes(131,132) which are installed within a reactor(100), and into which water flows; an air injection unit for injecting air into the reactor and guiding the injected air such that a space of two phases of water and air is formed between one pair of the electrodes; and a power source apply unit(140) for applying a power source to one pair of the electrodes. The air injection unit comprises an air diffuser(110) which is installed at the inlet side of the reactor, and on which a plurality of holes are formed, and a blower(120) for injecting air into the air diffuser through the holes. The one pair of electrodes comprise discharge electrodes(131) for performing electric discharge according to application of a power supply, and earth electrodes(132) facing the discharge electrodes.

Description

Underwater plasma discharging apparatus and discharging method using it}

1 is a view showing an underwater plasma discharge device according to an embodiment of the present invention,

2 to 4 is a view showing a deformable installation example of the diffuser formed with electrodes and pores in the underwater plasma discharge device shown in FIG.

<Description of Symbols for Major Parts of Drawings>

100 ... reactor 101 ... inlet

102 Outlet 110

120 ... Blower 131,132 ... discharge electrode, ground electrode (electrode)

140.Power supply unit

The present invention relates to an underwater plasma discharge device that is capable of causing plasma discharge in water and an underwater discharge method using the same.

Recently, research on advanced oxidation process (AOP) has been actively conducted to overcome the limitations of the conventional oxidation treatment process.

Advanced Oxidation is an advanced water treatment technology that oxidizes organic substances, such as ozone, OH radicals, hydrogen peroxide and UV, to oxidize pollutants in water, and has much stronger oxidation power than chlorine, chlorine dioxide and potassium permanganate. In addition to wastewater, it is gradually being applied to water treatment.

Advanced oxidation methods applied to water treatment have been developed in various ways, but most of them are applied in parallel with ozone and hydrogen peroxide, ozone and UV AOP, hydrogen peroxide and UV AOP.

Among them, ozone treatment utilizes the strong oxidizing power of ozone, and has excellent sterilization effect and is used as a disinfectant in water purification processes such as killing most bacteria even by a small amount of contact. In addition, it is effective for removing and removing odorous substances and the like by changing the properties of trace organic substances in raw water and widely used for oxidation treatment of artificial synthetic organic substances and the like.

However, ozone has the disadvantage of being highly selective, such as slow reaction with most organic materials or no reaction with any organic materials.

Therefore, in order to overcome the disadvantages of ozone treatment, oxidizing power of OH radicals is applied in parallel with ozone and hydrogen peroxide, ozone and UV AOP, hydrogen peroxide and UV AOP, and OH radicals with higher oxidation power than ozone are used as intermediate products. The method of producing and using for oxidation treatment has been studied and applied to various fields.

Underwater high voltage plasma discharge is being studied as one of the field of advanced oxidation method. Underwater pulse streamer discharge generates large amount of OH radicals by plasma, and hydrogen peroxide is generated by OH radical interaction in water to cause oxidation reaction. . The oxidation reaction of the active radicals (OH *, O *, O ₃ ) generated by the plasma has the advantage that it can be widely applied to water purification, such as decomposition of organic matter.

However, the study on underwater discharge has a problem in that when the electrode is submerged in water, electricity is charged to the discharge electrode in the medium and the plasma is not generated by electricity. For this reason, many methods have been studied for generating and discharging water surface discharge using bed needles, bed plates, flat plate flat plates, bed cylinders, and multi needle electrodes. However, in the case of such water surface discharge, the space where the treatment is performed is limited to the surface area, which is very narrow, which is an inefficient treatment method. Unstable discharge phenomenon is caused.

Recently, reactors for discharging in water by using various kinds of dielectrics to increase the amount of active radicals have been studied. However, failure to maintain a stable discharge under the condition that the medium is water causes insulation breakdown or discharge efficiency. The problem is still falling.

Therefore, there is a need for a new type of underwater plasma discharge method that can solve this problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above necessity, and an object of the present invention is to provide an underwater plasma discharge apparatus and method for stably maintaining plasma discharge in water, thereby making it possible to smoothly utilize active radicals generated at the time for water purification. There is this.

Other objects and advantages of the invention will be described below and will be appreciated by the embodiments of the invention. In addition, the objects and advantages of the invention may be realized by the means and combinations indicated in the claims.

Underwater plasma discharge apparatus of the present invention for achieving the above object, at least a pair of electrodes installed in the reactor to which water is introduced; An air injection unit for injecting air into the reactor to induce a two-phase space between water and air between the pair of electrodes; It includes; a power supply unit for applying power to the pair of electrodes.

In addition, an underwater plasma discharge method for achieving the above object comprises the steps of preparing a reactor provided with at least a pair of electrodes; Making a two-phase space between the pair of electrodes by supplying water and air into the reactor; And inducing plasma discharge by applying a pulse power to the pair of electrodes.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

1 illustrates a structure of an underwater plasma discharge apparatus according to an embodiment of the present invention.

As shown, the underwater plasma discharge apparatus of the present embodiment includes a reactor 100 in which a plurality of pairs of electrodes 131 and 132 are installed, and water, which is raw water to be treated, is introduced into the reactor 100. The inflow part 101 to be used and the outflow part 102 through which the purified water flows out are provided. In addition to the water, a unit for injecting air (or oxygen) into the reactor 100 is provided, which includes a diffuser having a pore formed under the reactor 100 chamber, and a fine portion of the diffuser 110. And a blower 120 for injecting air through the holes. That is, by injecting air together with water into the reactor 100, in the case of only one-phase space of the water to prevent the phenomenon that the electricity is immediately supplied to maintain a stable discharge of the plasma.

The electrodes 131 and 132 are composed of a discharge electrode 131 to which power is applied from the power supply unit 140 and a ground electrode 132 in a ground state, and is made of a corrosion-resistant metal rod or a metal mesh material. The surface is preferably coated with a dielectric layer. The purified water in this discharge device is ozone water, which can be usefully used for precision processing, such as semiconductor cleaning, and it is preferable to coat the dielectric layer because foreign matters falling off the electrode cannot be used for such precision applications. In operation, a high voltage pulse or AC power is applied from the power supply unit 140 according to the condition.

When the discharge device having such a configuration is operated, water and air, which are raw water to be treated, are injected together into the reactor 100. In addition, when a high voltage pulse or AC power is applied to the discharge electrode 131 in the power supply unit 140, plasma is emitted to emit blue light. At this time, between the electrodes (131, 132) is not simply present in the water as a medium, but because the air of the bubble form coexists with each other, as the current is directly energized, the breakdown of the insulation does not occur. That is, the presence of two phases of water and air prevents dielectric breakdown and maintains a stable plasma discharge state.

When plasma is maintained in this way, a large amount of OH radicals are continuously generated in water. They produce some hydrogen peroxide and cause oxidation reactions with organic matter in the water. That is, the active radicals do not act only on the water surface as in the prior art, but since a large amount of active OH radicals are generated in the water, the organic matters are oxidized and decomposed immediately, thereby greatly increasing the purification efficiency. In addition, since the oxidation reaction is continuously performed as long as the plasma is stably maintained, the processing speed is also considerably faster. Thereafter, the purified water or activated water is discharged through the outlet 102 to return to a reusable state.

Therefore, by discharging the plasma in the two-phase space of water and air, it is possible to maintain a stable plasma discharge state, thereby securing a large amount of active radicals in water, thereby improving the water treatment efficiency. Experiments show that 5 times the volume of water can be purged for the same amount of time compared to conventional surface discharge.

On the other hand, the relative position of the diffuser 110 and the electrodes 131, 132, the air is injected into the diffuser 110, 210, 410 as shown in Figures 1, 2 and 4 Although the discharge electrodes 131, 231, 431 and the ground electrodes 132, 232, 432 may be arranged to be positioned above, the diffuser 310 between the two electrodes 331, 332 as shown in FIG. 3. ) May be arranged to come. That is, not only the reactor 100 structure of the first embodiment described above, but also an arrangement structure of electrodes such as the reactors 200, 300, 400 shown in the second, third, and fourth embodiments shown in FIGS. 2 to 4. It is also possible to adopt. The electrodes may also be used to face the plurality of rod-shaped electrodes 131 and 132 as shown in FIG. 1, or may be used in two or more stages by alternately installing the rod-shaped electrodes 431 and 432 as shown in FIG. 4. In addition, a mesh type electrode may be used as shown in FIGS. 2 and 3. In particular, in the structure of FIG. 4, the discharge electrode 431 and the ground electrode 432 are alternately planarly arranged so that discharge occurs between them, and is arranged in multiple stages to increase efficiency. That is, even if the shape and arrangement of the electrode are modified and selected as necessary, only two-phase space can be produced, and the effects of the present invention can be obtained without difficulty.

As described above, the underwater plasma discharge device of the present invention provides the following effects.

First, by discharging the plasma in the two-phase space of water and air, it is possible to maintain a stable plasma discharge state, thereby ensuring a large amount of active radicals in the water can increase the water treatment efficiency.

Second, since active radicals are produced in water, they cause oxidation reactions with organics, so the disappearance of active radicals is minimized and the utilization rate is high.

Third, since the two-phase space can be implemented with a relatively simple reactor, the economic burden is very small.

As mentioned above, although this invention was demonstrated by the limited embodiment and drawing, this invention is not limited by this, The person of ordinary skill in the art to which this invention belongs, Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

Claims (9)

At least one pair of electrodes installed in the reactor into which water is introduced; An air injection unit for injecting air into the reactor to induce a two-phase space between water and air between the pair of electrodes; And a power supply unit for applying power to the pair of electrodes. The method of claim 1, The air injection unit is an underwater plasma discharge device characterized in that it comprises a diffuser formed in the pores installed in the mouth of the reactor, and a blower for injecting air through the holes of the diffuser. The method of claim 1, The pair of electrodes is any one selected from the corrosion-resistant metal rod and the metal mesh, the underwater plasma discharge device, characterized in that the dielectric coating on the outer surface. The method of claim 1, And the pair of electrodes includes a discharge electrode which discharges as power is applied, and a ground electrode facing the discharge electrode. The method of claim 1, The air injection unit includes a porous diffuser, Underwater plasma discharge apparatus, characterized in that the diffuser is disposed below the pair of electrodes. The method of claim 1, The air injection unit includes a porous diffuser, And the diffuser is disposed between the pair of electrodes. The method of claim 1, And the power supply unit applies a high voltage pulse or an alternating current power source. Preparing a reactor provided with at least one pair of electrodes; Making a two-phase space between the pair of electrodes by supplying water and air into the reactor; Inducing plasma discharge by applying power to the electrode; Underwater plasma discharge method comprising a. The method of claim 8, Underwater plasma discharge method characterized in that the power applied to the electrode is a high voltage pulse or AC power.

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