KR100701400B1 - Non-thermal Plasma Pre-ionizer for the Removal of Oil Mist - Google Patents

Abstract

A non-thermal plasma pre-ionizer for removing oil mist is provided to attach the fine oil mist to a dust collecting pole of an electrostatic precipitator by ionizing the oil mist by generating non-thermal plasma in the gas to be treated. The non-thermal plasma pre-ionizer installed at the front end of an electrostatic precipitator formed at an air passage to ionize the fine oil mist in the air by generating plasma by applying AC(Alternating Current) high voltage has a wire-cylinder electrode disposed vertically in the flow direction of the air to generate a wire-cylinder dielectric barrier discharge. The wire-cylinder electrode comprises several or tens of holes formed on a metal plate(34) used as an outer electrode to be a passage for the air; dielectric material tubes(36) fitted to each hole; and a discharge electrode(32) installed in the middle portions of each dielectric material tube. Therefore, non-thermal plasma is generated between the dielectric material tube and the discharge electrode by AC high voltage applied to the metal plate and the discharge electrode.

Description

Non-thermal Plasma Pre-ionizer for the Removal of Oil Mist

1 is a schematic view showing the application of the low-temperature plasma precharge device of the present invention.

Figure 2 is a side view of the precharge device showing the arrangement of the surface discharge electrode to generate a low temperature plasma in the present invention.

Figure 3 (a) is a side view illustrating a state in which the precharge device according to the present invention composed of a wire-cylinder electrode

Figure 3 (b) is a front view illustrating a state in which the precharge device according to the present invention composed of a wire-cylinder electrode

*** Explanation of symbols for main parts of drawing ***

10, 16: filters

12: non-thermal plasma pre-ionizer

14: electrostatic precipitator

20: outer electrodes

22: dielectric materials

24: inner electrodes

26, 38: high voltage AC power supply

32: screw type inner electrodes

34: metal plate

36: dielectric materials tube

The present invention relates to a non-thermal plasma pre-ionizer device, which can be easily removed from an electrostatic precipitator by charging an oil mist in a gas to be purified. A low temperature plasma precharger for oil mist removal.

Processes such as metal processing, fiber manufacturing, and food processing produce fine oil mist of 1 μm or less. These oil mists are generally organic compounds that are harmful to the human body. As a representative example, since the smoke produced during processing foods contains carcinogens such as dioxins and furans, the US government has used MACT in the food processing industry as well as other industrial processes since 2001. (maximum achievable control technology) standard. However, the oil mist particles generated in the above-mentioned process are fine, which makes it difficult to completely remove the existing mist collector. In order to overcome this problem, a method of placing a precharge device in front of the electrostatic precipitator to charge the oil mist and collecting it with the electrostatic precipitator is used.

Conventionally, U.S. Patent No. 6,428,61 uses a preliminary charging device for removing oil mist, but the patent simply applies a high voltage of about 8.2 kV to the preliminary charging device. Patent (Japanese Patent Laid-Open No. 11-179122) has a structure in which a high voltage is applied to a sharp needle like a needle to charge an oil mist with a cation and remove it immediately. The preliminary charging device of the German patent No. 10132582 is similar to the Japanese patent mentioned above, but is configured in the form of an array of precharged electrodes in which corona discharge occurs.

As described above, to date, the preliminary charging device for removing oil mist has a wire or needle-plate or cylinder structure, and the wire or needle Since it has a form of applying a high voltage plus, it is difficult to effectively charge fine oil mist flowing at a high flow rate.

In addition, the discharge generated by applying the DC high voltage to the above-mentioned precharge device of the metal form is easily unstable as the dust (moisture) and the presence of dust (moisture) easily flows into the arc discharge current is very unstable It is disadvantageous to charge oil mist and has a lot of energy loss.

In addition, the direct current discharge has a problem that the discharge is started at a relatively high voltage compared to the alternating current.

In addition, oil mists generated in mechanical, textile and food processing processes are mostly less than 1 μm in diameter, making them difficult to remove with conventional filters.

In addition, the use of a high-density filter to remove such fine oil mist has a disadvantage that takes a lot of differential pressure.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a low temperature plasma precharge device for effectively charging fine oil mist by applying an alternating current high voltage to an electrode covered with a dielectric to generate low temperature plasma.

In order to achieve the above object, the present invention is applied to the pre-charge device installed in front of the electrostatic precipitator when the air containing the oil mist is introduced, it generates a low temperature plasma to charge the fine oil mist effectively in the electrostatic precipitator It provides a method by which oil mist can be removed.

      Low temperature plasma precharge device for removing oil mist according to the present invention

It is characterized in that there is a preliminary charging device that causes one of the surface discharge and the wire-cylinder dielectric barrier discharge using an AC high voltage power supply.

       In addition, the low temperature plasma precharge device includes a structure of one of the electrode is covered with a dielectric and coated with a dielectric; The discharge electrode is characterized in that the structure of one of the metal itself and both surfaces are covered with a dielectric.

       In addition, the preliminary charging device is characterized in that consisting of a layer of electrodes causing a surface discharge.

       In addition, preliminary charging device for making a few to several dozen holes of a certain diameter in the metal plate, which is an electrically conductive conductor, sandwiching the dielectric tube in each hole and the discharge electrode is installed in the center of the dielectric tube; The discharge electrode is a screw rod having one of a metal rod and a thread; The discharge electrode has a structure covered with one of a metal and a dielectric.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a schematic diagram to which the low-temperature plasma precharge device according to the present invention is applied.

Referring to FIG. 1, the gas containing the oil mist is first filtered by the filter 10. Fine oil mist, which cannot be removed by a general filter, is charged while passing through the low temperature plasma precharge device 12. The charged oil mist particles are attached to and removed from the dust collector of the electrostatic precipitator 14. The gas passing through the electrostatic precipitator 14 is filtered once more by the filter 16.

2 illustrates a surface discharge type precharge device capable of generating a uniform and stable corona discharge through an entire passage through which a gas to be treated passes. When the AC high voltage is applied to the internal electrode 24 and the external electrode 20 in the AC high voltage power supply device 26, a low temperature plasma is generated between the dielectric 22 and the internal electrode 24. In the low temperature plasma atmosphere, electrons, small molecular weight anions and cations are present. The former attaches to the oil mist to make the oil mist anion, and the cations and anions in the cold plasma transfer their charge to the oil mist to make the oil mist anion or cation. The internal electrode 24 is either a conductor (metal) itself or a dielectric covering on both sides. The thickness of the dielectric 22 determines the capacitance of the dielectric 22. The gas passing through the low-temperature plasma precharge device 12 can be seen as a capacitor when a high voltage is not applied, but as a load (resistance) during discharge. Therefore, since the low-temperature plasma precharged electrodes are considered to be RC circuits at the time of discharge, the optimum frequency of the AC power supply device suitable for the power supplied to the reactor is determined.

In general, the discharge start voltage is lowered as the frequency of the AC power supply increases. Therefore, the AC high voltage power supply 26 is designed to be variable up to several tens of kHz so that low temperature plasma can be generated at low voltage if possible.

3 (a) and 3 (b) are side and front views illustrating a state in which the precharge device according to the present invention is configured as a wire-cylinder electrode, and is shown in FIG. 3 as a preliminary view according to another embodiment of the present invention. The charging device is arranged perpendicular to the air flow direction and consists of a wire-cylinder electrode which causes a wire-cylinder dielectric barrier discharge. The wire-cylinder electrode has a plurality of dozens of holes that serve as air passages in the metal plate 34, which is a conductor that can be used as an external electrode, and the dielectric tube 36 is inserted into each of the holes. The discharge electrode 32 is disposed in the center of the dielectric tube 36 and the low temperature plasma is formed between the dielectric tube 36 and the discharge electrode 32 by an alternating high voltage applied to the metal plate 34 and each discharge electrode 32. Configure to generate
In this case, the metal plate 34 may use an aluminum plate, and a plurality of holes are formed in the aluminum plate, and a dielectric tube 36 having a cylindrical shape is inserted therein, and a discharge electrode 32 is installed at the center of the dielectric tube 36. do. The discharge electrode may be used by generating a low temperature plasma using a threaded electrode having a screw thread on the outer circumferential surface or by covering a discharge tube with a dielectric tube. When an alternating current high voltage is applied to the anode, a low temperature plasma is generated between the dielectric tube 36 and the discharge electrode 32. In the low temperature plasma precharge device of the type illustrated in FIG. There is also an advantage that serves as a distribution plate to enable uniform distribution of air on the flow path to make the gas flow uniform.

The best embodiments have been disclosed in the drawings and specification above. The specific terminology used herein is for the purpose of describing the present invention only and is not intended to be limiting of meaning or the scope of the invention as set forth in the claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the present invention without being limited to the literary meaning described in the specification.

The present invention generates a low-temperature plasma in the gas to be treated by applying an alternating current high voltage to the preliminary charging device to charge the oil mist so that the charged fine oil mist is attached to and removed from the dust collector of the electrostatic precipitator. Filtering the gas through the dust collector and once again through the filters installed in the filter effectively removes gas containing oil mist of 1 μm or less, which is difficult to remove by a general filter, and makes the flow of gas uniform. Has

Claims (5)

In the precharge device is installed in front of the electrostatic precipitator on the air flow path, and generates a plasma by applying an alternating current high voltage to charge the fine oil mist in the air, The precharger is composed of a wire-cylinder electrode disposed perpendicular to the flow direction of air to cause a wire-cylinder dielectric barrier discharge, The wire-cylinder electrode, In the metal plate 34, which is a conductor that can be used as an external electrode, a plurality of dozens of holes for air flow are formed, and the dielectric tubes 36 are inserted in the respective holes, and the center of each dielectric tube 36 is formed. The discharge electrode 32 is installed at the discharge electrode 32 so as to generate a low temperature plasma between the dielectric tube 36 and the discharge electrode 32 by an alternating current high voltage applied to the metal plate 34 and each discharge electrode 32. Low temperature plasma precharge device for oil mist removal. delete delete The method of claim 1, wherein the discharge electrode 32, Low temperature plasma precharge device for removing oil mist, characterized in that the threaded electrode formed on the outer circumferential surface. The hole formed in the metal plate 34, Low temperature plasma precharge device for oil mist removal, characterized in that formed in the same size for uniform distribution of air on the air flow path.

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