Patent Description:
An air purification device purifies air by collecting or decomposing fine dust and contaminants in gas, for example, air. The air purification device may be applied to industrial dust collection facilities and air conditioning/ventilation systems in buildings.

Representative methods of removing fine dust and contaminants from the air include a filter method and an electrical dust collection method. The filter method is a method of collecting fine dust and contaminants contained in the air using a filter. The filter method may have excellent removal efficiency of fine dust and contaminants and filter out various types of fine dust and contaminants from the air. However, when the amount of fine dust collected in the filter increases, the performance of the filter may deteriorate, and the pressure drop by the filter may increase. Filters may be regularly maintained or replaced. In addition, the electrical dust collection method purify air by ionizing contaminants in the air and adsorbing contaminants to a strong dust collection plate using the principle of electric discharge. However, the electric current collection method is difficult to regularly wash and manage the dust collection plate of a metal material.

Document <CIT> discloses a reactive bed plasma device including an active alternating current discharge plasma permeating a dielectric packed bed.

Document <CIT> discloses a plasma treating device including a plasma reactor having a plasma treating space for effecting an electric discharge under the atmospheric pressure to generate a plasma so as to plasma-treat the object gas.

Document <CIT> discloses an apparatus for the decontamination of air, the apparatus comprising a means for directing a stream of air through a housing containing a non-thermal plasma cell.

Document <CIT> discloses a substrate processing apparatus that has a process chamber and an effluent treatment reactor. The process chamber has a substrate support, a process gas supply, a gas energizer, and an exhaust conduit. The effluent treatment reactor has an effluent inlet to receive effluent from the exhaust conduit of the process chamber, a plasma cell having one or more electrodes electrically connected to a voltage source adapted to electrically bias the electrodes to couple energy to effluent received in the plasma cell, a scrubbing cell coaxially exterior to the plasma cell, the scrubbing cell having a scrubbing fluid inlet to introduce scrubbing fluid into effluent in the scrubbing cell and a scrubbing fluid outlet, and an effluent outlet to release the treated effluent.

Provided are an air purification device and an air purification method capable of removing fine dust and contaminants through discharge plasma and solution spray.

Provided are an air purification device and an air purification method with improved performance of removing fine dust and contaminants.

According to an aspect of an embodiment, an air purification device includes: a reactor of a hollow shape extending in one direction; a discharge plasma generator including a first electrode disposed on an outer wall of the reactor and a second electrode disposed inside the reactor, and configured to generate a discharge plasma in a certain discharge region; a plurality of dielectric particles disposed on a packed-bed of the reactor, wherein the discharge region includes the packed bed; a liquid supplier configured to supply a liquid into the reactor and to spray the liquid to the packed-bed; and a liquid recoverer configured to recover the liquid discharged from the reactor.

The liquid may include a basic aqueous solution.

An alkaline strength (PH) of the basic aqueous solution may be determined according to an ozone concentration inside the reactor.

The liquid may be an aqueous sodium hydroxide solution having a molar concentration equal to or more than about <NUM> mmol/L and equal to or less than about <NUM> mmol/L.

The air purification device may further include a pump configured to generate a pressure for delivering the liquid stored in the liquid recoverer to the liquid supplier.

A porosity of the packed-bed may be more than about <NUM>% and equal to or less than about <NUM>%.

An average particle diameter of the plurality of dielectric particles may be equal to or more than about <NUM> and equal to or less than about <NUM>.

The plurality of dielectric particles may include at least one of silicon oxide, boron oxide, aluminum oxide, manganese oxide, titanium oxide, barium oxide, copper oxide, and magnesium oxide, or at least one of mixtures of the substances.

A voltage equal to or more than about <NUM> kV and equal to or less than about <NUM> kV may be applied to the discharge region.

The air purification device may further include a high voltage generator configured to apply a high voltage to an inside of the reactor; and a controller configured to control a generation voltage of the high voltage generator, and the controller is configured to transmit a control signal for increasing a magnitude of the voltage generated by the high voltage generator to the high voltage generator as an inflow amount of contaminated air flowing into the reactor increases.

The first electrode may be a silver paste film.

The second electrode may extend in the one direction and may be spaced apart from the first electrode with a certain distance therebetween.

The reactor may be a glass conduit extending in the one direction.

According to an aspect of another embodiment, an air purification method includes: making a liquid flow into the reactor by spraying the liquid to the packed-bed of the reactor; generating a discharge plasma by applying a certain voltage to the first electrode and the second electrode; making the contaminated air flow into the reactor; and discharging the liquid and purified air from the reactor.

The air purification method may further include supplying the liquid discharged from the reactor into the liquid supplier.

A voltage equal to or more than about <NUM> kV and equal to or less than about <NUM> kV may be applied to generate the discharge plasma.

The air purification method may further include removing ozone using a catalyst at a rear end of the reactor.

The catalyst may include at least one of manganese oxide, copper oxide, and aluminum oxide, or at least one of mixtures between the substances.

As used herein, the term "and/or" may include any and all combinations of one or more of the associated listed items.

In the following drawings, like reference numerals refer to like elements throughout, and the size of each element in the drawings may be exaggerated for clarity and convenience of description.

<FIG> is a schematic configuration diagram of an embodiment of an air purification device <NUM>. <FIG> is an enlarged cross-sectional view of a part of the air purification device <NUM> shown in <FIG>.

Referring to <FIG> and <FIG>, the air purification device <NUM> according to an embodiment may include a reactor <NUM> in a hollow shape (e.g., tube shape) extending in one direction, a discharge plasma generator <NUM> generating discharge plasma in the reactor <NUM>, a plurality of dielectric particles <NUM> disposed in a packed-bed <NUM> of the reactor <NUM>, liquid supplier <NUM> that supplies liquid into the inside of the reactor <NUM>, a liquid recoverer <NUM> recovering the liquid discharged from the reactor <NUM>, a pump <NUM> generating pressure for transferring the liquid stored in the liquid recoverer <NUM> to the liquid supplier <NUM> and a controller <NUM>.

In the present specification, contaminated air Air<NUM> refers to a mixed gas including at least one of fine dust PM, a water soluble organic compound VOCsol, and a water insoluble organic compound VOCinsol. As an example, the fine dust PM may include small fine dust having a diameter equal to or less than <NUM> µm and ultrafine dust of which diameter is equal to or less than <NUM> µm. In addition, the water soluble organic compound VOCsol is a volatile organic compound, and may include a gaseous substance that may be trapped in water or an aqueous solution and removed, for example, ammonia (NH<NUM>), acetaldehyde (CH<NUM>CHO), and acetic acid (CH<NUM>COOH). In addition, the water insoluble organic compound VOCinsol is a volatile organic compound that is not collected in water or aqueous solution, and may include, for example, benzene (C<NUM>H<NUM>), formaldehyde (CH<NUM>O), toluene (C<NUM>H<NUM>CH<NUM>), etc. However, the present disclosure is not limited thereto, and any gas that may be decomposed and ionized by a discharge plasma and discharged to the outside of the reactor <NUM> may be included in the contaminated air Air<NUM>.

The reactor <NUM> forms a flow path of the contaminated air Air<NUM> and liquid. In addition, the packed-bed <NUM> in which the plurality of dielectric particles <NUM> are disposed is provided inside the reactor <NUM>. As an example, the packed-bed <NUM> may be a discharge region in which the discharge plasma is generated by using the discharge plasma generator <NUM>. However, the present disclosure is not limited thereto, and another region including the packed-bed <NUM> may be a discharge region.

The reactor <NUM> according to an embodiment may extend in one direction (e.g., direction from top to bottom as shown in <FIG> and <FIG>) and may have the hollow shape through which the contaminated air Air<NUM> and liquid may flow. However, the shape of the reactor <NUM> is not particularly limited, and for example, the cross-sectional shape of the reactor <NUM> may be various, such as a circular shape or a polygonal shape. The cross-sectional shape of the reactor <NUM> of the present embodiment is circular. As an example, the reactor <NUM> may be a glass conduit or an aluminum conduit extending in one direction. However, the present disclosure is not limited thereto, and any hollow conduit capable of generating discharge plasma may be used as the reactor <NUM>.

According to an embodiment, the contaminated air Air<NUM> is supplied to the reactor <NUM> through the contaminated air inlet <NUM> by a blower (not shown). The contaminated air Air<NUM> moves along the air flow path formed by the reactor <NUM> and is discharged through a purified air outlet <NUM>. In addition, the liquid supplied from the liquid supplier <NUM> to be described later may be introduced through a first end <NUM> of the reactor <NUM>, and the liquid to be stored in the liquid recoverer <NUM> may be discharged through a second end <NUM> of the reactor <NUM>.

The discharge plasma generator <NUM> may include a first electrode <NUM> disposed on the outer wall of the reactor <NUM>, a second electrode <NUM> disposed inside the reactor <NUM>, and a high voltage generator <NUM>. The first electrode <NUM> according to an embodiment is a ground electrode, and the discharge region (i.e., the packed-bed <NUM>) in which discharge plasma may be generated may be surrounded by the first electrode <NUM>. For example, the first electrode <NUM> may be a silver paste film and disposed to surround the outer wall of the reactor <NUM>.

In addition, the second electrode <NUM> is a power electrode, and may be disposed to be spaced apart from the first electrode <NUM> with a certain distance therebetween in the discharge region in which discharge plasma may be generated. For example, the second electrode <NUM> may be a steel wire extending in one direction (e.g., vertical direction in <FIG>) and disposed inside the reactor <NUM>.

Also, the high voltage generator <NUM> may apply a high voltage to the discharge region in which discharge plasma may be generated. The high voltage generator <NUM> according to an embodiment may include a sinusoidal AC power supply and a transformer. The high voltage generator <NUM> may continuously apply a high voltage to the inside of the reactor <NUM>, for example, to the discharge region in which discharge plasma may be generated through the above-described electric system. As an example, the voltage applied to the discharge region may be equal to or more than 2kV and equal to or less than 500kV, and a frequency of the AC power may be equal to or more than <NUM> and equal to or less than <NUM>, but the present disclosure is not limited thereto. In addition, a separation distance between the first electrode <NUM> and the second electrode <NUM> in the discharge region may be equal to or more than <NUM> or equal to or less than <NUM>, and accordingly, an electric field equal to or more than <NUM> kV/cm and equal to or less than <NUM> kV/cm may be applied to the discharge region (i.e., the packed-bed <NUM>).

The plurality of dielectric particles <NUM> may be disposed in the packed-bed <NUM> inside the reactor <NUM>. The plurality of dielectric particles <NUM> according to an embodiment may induce polarized and ionized contaminants. For example, the plurality of dielectric particles <NUM> may include a dielectric material that may be polarized in the discharge region generated by the discharge plasma generator <NUM>. As an example, the plurality of dielectric particles <NUM> may include at least one of silicon oxide, boron oxide, aluminum oxide, manganese oxide, titanium oxide, barium oxide, copper oxide, and magnesium oxide, or at least one of mixtures of the substances.

In addition, as an example, the plurality of dielectric particles <NUM> may define certain pores to adjust the time that the contaminated air Air<NUM> remains in the reactor <NUM>. For example, the plurality of dielectric particles <NUM> may have a bead shape having a certain particle diameter, for example, an average diameter equal to or more than <NUM> and equal to or less than <NUM>. However, the present disclosure is not limited thereto, and the plurality of dielectric particles <NUM> may have another three-dimensional (3D) shape such as an arbitrary rectangular parallelepiped.

The plurality of dielectric particles <NUM> may be disposed on the packed-bed <NUM>, and accordingly, the packed-bed <NUM> on which the plurality of dielectric particles <NUM> are disposed may include a porosity more than <NUM>% and equal to or less than <NUM>%. As an example, in order to adjust the time that the contaminated air Air<NUM> and liquid remain in the reactor <NUM>, the porosity of the packed-bed <NUM> may be adjusted by adjusting the diameter of the plurality of dielectric particles <NUM> disposed on the packed-bed <NUM>. For example, it is necessary to reduce the porosity of the packed-bed <NUM> in order to increase the time that the contaminated air Air<NUM> and liquid remain in the reactor <NUM>. At this time, by reducing the average diameter of the plurality of dielectric particles <NUM>, the porosity of the packed-bed <NUM> may be reduced.

In addition, a water film <NUM> (refer to <FIG>) of liquid may be formed on the surface of each of the plurality of dielectric particles <NUM> according to an embodiment to collect the contaminated air Air<NUM>. The liquid supplied from the liquid supplier <NUM> which will be described later moves downward in a gravity direction G. In this case, the liquid moving downward and each of the plurality of dielectric particles <NUM> may contact each other. The water film <NUM> may be formed on the surface of each of the plurality of dielectric particles <NUM> by contacting the liquid moving downward and each of the plurality of dielectric particles <NUM>. The contaminated air Air<NUM> disposed adjacent to the water film <NUM> described above may be collected by the water film <NUM> and discharged to the outside of the reactor <NUM> together with the liquid.

The liquid supplier <NUM> may store liquid and supply the stored liquid to the reactor <NUM>. As an example, the liquid supplier <NUM> may include one or more spray nozzles <NUM> capable of spraying the liquid stored in the liquid supplier <NUM> into the reactor <NUM>. The liquid stored in the liquid supplier <NUM> may be any fluid capable of collecting the contaminated air Air<NUM> and discharging the contaminated air Air<NUM> to the outside of the reactor <NUM>. For example, the liquid may be water or a basic aqueous solution.

As an example, water stored in the liquid supplier <NUM> is sprayed into the reactor <NUM> in the form of fine droplets through the spray nozzle <NUM>. In this process, the liquid adheres to the surface of each of the plurality of dielectric particles <NUM> to form the water film <NUM>. Part of the contaminated air Air<NUM> is attracted to each of the plurality of dielectric particles <NUM> and collected in the water film <NUM>. In addition, the flow direction of the contaminated air Air<NUM> may be formed to be windingly by the plurality of dielectric particles <NUM>. Accordingly, the contact region between the water film <NUM> formed on the surface of each of the plurality of dielectric particles <NUM> and the contaminated air Air<NUM> may increase, and thus the contaminated air Air<NUM> may be more easily collected in the water film <NUM>. In the reactor <NUM>, a gas-liquid mixture fluid in which the contaminated air Air<NUM> and liquid are mixed is formed. The gas-liquid mixture fluid flows toward the second end <NUM> of the reactor <NUM> and is discharged to the outside of the reactor <NUM>.

As an example, ozone <NUM><NUM> may be generated from oxygen O<NUM> in the air by the discharge plasma generator <NUM>. When ozone <NUM><NUM> is generated in the reactor <NUM> and the concentration of ozone <NUM><NUM> increases, the basic aqueous solution may be stored in the liquid supplier <NUM> to prevent this. As used herein, the basic aqueous solution is defined as an aqueous solution with a pH greater than <NUM>. As an example, the basic aqueous solution may be an aqueous sodium hydroxide NaOH solution having a molar concentration equal to or more than <NUM> mmol/L and equal to or less than <NUM> mmol/L. An alkaline strength PH of the basic aqueous solution may also be determined according to the concentration of ozone <NUM><NUM> in the reactor <NUM>. For example, when the concentration of ozone <NUM><NUM> in the reactor <NUM> increases, the alkaline strength PH of the basic aqueous solution may also increase in proportion thereto.

The liquid recoverer <NUM> may store the liquid discharged to the outside of the reactor <NUM> and supply the stored liquid back to the liquid supplier <NUM>. As an example, the liquid recoverer <NUM> stores an emission in a gas-liquid mixture state discharged to the outside of the reactor <NUM>. At this time, the liquid recoverer <NUM> may purify the emission in a gas-liquid mixture state through a certain purification device (not shown). The purified liquid may be supplied back to the liquid supplier <NUM> using a pump <NUM> and may be reused in the liquid supplier <NUM>.

The controller <NUM> may control, for example, at least one other component (e.g., a hardware or software component) connected to the controller <NUM> by executing software (e.g., a program) and perform various data processing or calculations. According to an embodiment, the controller <NUM> may generate a control signal with respect to the high voltage generator <NUM> to control the level of voltage generated by the high voltage generator <NUM>. For example, when an inflow amount of the contaminated air Air<NUM> flowing into the reactor <NUM> increases or the concentration of a contamination material increases, the controller <NUM> may transmit the control signal that increases the magnitude of the voltage generated by the high voltage generator <NUM> to the high voltage generator <NUM>. Accordingly, even when the inflow amount of the contaminated air Air<NUM> increases, the purification efficiency of the contaminated air Air<NUM> may be maintained or increased.

A catalyst reactor <NUM> may be disposed at the rear end of the reactor <NUM> to remove ozone <NUM><NUM> discharged from the reactor <NUM> using a catalyst. As an example, the catalyst included in the catalyst reactor <NUM> may include at least one of manganese oxide, copper oxide, and aluminum oxide, or at least one of mixtures between the substances.

As described above, the air purification device <NUM> may purify the contaminated air Air<NUM> by simultaneously applying decomposition by discharge plasma and capture by liquid. Hereinafter, purification of the contaminated air Air<NUM> using discharge plasma and contaminated air Air<NUM> by classifying the fine dust PM, the water soluble organic compounds VOCsol, the water insoluble organic compound VOCinsol, and ozone <NUM><NUM> included in the contaminated air Air<NUM> is described in more detail.

<FIG> are schematic diagrams of an enlarged region M shown in <FIG>.

Referring to <FIG>, when a high voltage is applied to the packed-bed <NUM> using the discharge plasma generator <NUM> according to an embodiment, electrons e may be generated in the second electrode <NUM> itself disposed inside the reactor <NUM>, or electrons e may be generated in the gas around the second electrode <NUM>, and thus discharge plasma may be formed around the second electrode <NUM>. Electrons e generated around the second electrode <NUM> move to the second electrode <NUM> to which an opposite charge is applied by electrical attraction. Meanwhile, ions from which electrons are separated electrically charge and surround the fine dust PM, so that the fine dust PM has a positive charge.

As an example, when a high voltage is applied to the packed-bed <NUM> using the discharge plasma generator <NUM>, an electric field is applied between the first electrode <NUM> and the second electrode <NUM>. At this time, the plurality of dielectric particles <NUM> disposed in the electric field may be polarized. As an example, as shown in <FIG>, the dielectric particle <NUM> disposed to face the second electrode <NUM> has a negative charge. As described above, the fine dust PM having the positive charge by plasma moves toward the plurality of dielectric particles <NUM> to which the opposite charge is applied by electric attraction. At this time, the water film <NUM> by a liquid is formed on the surface of each of the plurality of dielectric particles <NUM>, and fine dust PM having thea positive charge is collected by the water film <NUM>. The liquid forming the water film <NUM> moves in a direction of gravity G and is discharged to the outside of the reactor <NUM>. Accordingly, the fine dust PM collected in the liquid may also be discharged to the outside of the reactor <NUM> together with the liquid.

As described above, by filling the packed-bed <NUM> with the plurality of dielectric particles <NUM> and spraying the liquid to the packed-bed <NUM>, the water film <NUM> may be formed on the surface of each of the plurality of dielectric particles <NUM>. Accordingly, a contact region between the liquid forming the water film <NUM> and the fine dust PM may be improved, thereby improving a collection rate of the fine dust PM. In addition, by changing the fine dust PM to a specific charge state (e.g., positive charge) using the discharge plasma generator <NUM>, and by changing the plurality of dielectric particles <NUM> to an opposite charge state (e.g., negative charge), attraction force may be formed between the plurality of dielectric particles <NUM> and the fine dust PM. Accordingly, the water film <NUM> formed on each of the plurality of dielectric particles <NUM> may improve the collection rate of the fine dust PM.

The air purification device <NUM> according to an embodiment may simultaneously also remove not only the fine dust PM but also the water soluble organic compound VOCsol and the water insoluble organic compound VOCinsol by using the liquid sprayed into the discharge plasma generator <NUM> and the reactor <NUM>.

Referring to <FIG>, a primary method of removing the water soluble organic compound VOCsol according to an embodiment is to dissolve the water soluble organic compound VOCsol in the liquid supplied to the inside of the reactor <NUM> and discharge the water soluble organic compound VOCsol together with the liquid. However, according to a flow rate of the water soluble organic compound VOCsol, the time when the water soluble organic compound VOCsol remains in the reactor <NUM> may not be relatively sufficient. At this time, because the contact between the water soluble organic compound VOCsol and the liquid is not sufficient, the water soluble organic compound VOCsol may not be sufficiently removed.

In order to supplement the above-described primary method, the water soluble organic compound VOCsol may be directly decomposed using the discharge plasma generator <NUM>. When a high voltage is applied to the packed-bed <NUM> using the discharge plasma generator <NUM> according to an embodiment, the water soluble organic compound VOCsol may be decomposed using OH radical (OH·). As an example, when the high voltage is applied to the packed-bed <NUM> using the discharge plasma generator <NUM>, oxygen (O<NUM>) in the air around the second electrode <NUM> disposed inside the reactor <NUM> and water molecules (H<NUM>O) are broken into a neutral gas ionic state (a plasma state), and OH radical (OH·) may be generated from this ion. As an example, acetic acid (CH<NUM>COOH), acetaldehyde (CH<NUM>CHO), and methane (CH4) in the water soluble organic compound VOCsol may be decomposed into carbon dioxide (CO<NUM>) and water (H<NUM>O) as shown in Reaction Equations <NUM> to <NUM> below.

[Reaction Equation <NUM>]     CH<NUM>COOH+4OH+O<NUM> → 2CO<NUM>+<NUM><NUM>O.

[Reaction Equation <NUM>]     CH<NUM>CHO+6OH+O<NUM> → 2CO<NUM>+<NUM><NUM>O.

[Reaction Equation <NUM>]     CH<NUM>+4OH+O<NUM> → CO<NUM>+<NUM><NUM>O.

Carbon dioxide (CO<NUM>) and water (H<NUM>O) which are decomposition products may be discharged to the outside of the reactor <NUM> together with the liquid. As described above, the removal efficiency of the water soluble organic compound VOCsol may be improved by using the primary method of dissolving the water soluble organic compound VOCsol with the liquid and the secondary method using the discharge plasma generator <NUM>.

The water insoluble organic compound VOCinsol may not be dissolved in the liquid supplied to the reactor <NUM>, for example, water or a basic aqueous solution. Therefore, the method of dissolving and removing the water insoluble organic compound VOCinsol in the liquid may not be used.

According to an embodiment, the discharge plasma generator <NUM> may be used to directly decompose the water insoluble organic compound VOCinsol. When a high voltage is applied to the packed-bed <NUM> using the discharge plasma generator <NUM> according to an embodiment, the water insoluble organic compound VOCinsol may be decomposed by using OH radical (OH·). As an example, when the high voltage is applied to the packed-bed <NUM> using the discharge plasma generator <NUM>, oxygen (O<NUM>) in the air around the second electrode <NUM> disposed inside the reactor <NUM> and water molecules (H<NUM>O) are broken into a neutral gas ionic state (a plasma state), and OH radical (OH·) may be generated from this ion. As an example, water soluble organic toluene (C<NUM>H<NUM>CH<NUM>) may be decomposed into carbon dioxide (CO<NUM>) and water (H<NUM>O) by OH radical (OH·).

Carbon dioxide (CO<NUM>) and water (H<NUM>O) which are decomposition products may be discharged to the outside of the reactor <NUM> together with the liquid. As described above, the air purification device <NUM> according to an embodiment may improve the removal efficiency of the water insoluble organic compound VOCinsol by using the decomposition method using the discharge plasma generator <NUM>.

<FIG> is a graph showing plasma voltage and removal efficiency of the water soluble organic compound VOCsol according to an embodiment.

At atmospheric pressure and a temperature close to room temperature, reaction between the air purification device <NUM> and the water soluble organic compound VOCsol is carried out.

A volume flow rate of a mixture (NH3: CH3CHO: CH3COOH = <NUM>:<NUM>:<NUM>) of ammonia (NH<NUM>), acetaldehyde (CH<NUM>CHO), and acetic acid (CH<NUM>COOH) which are water soluble organic compounds VOCsol is <NUM>/min. As a dielectric barrier of the reactor <NUM>, a quartz tube having an inner diameter of <NUM> and a thickness of <NUM> is used. A stainless steel rod of a <NUM> diameter is used as a second electrode (<NUM>: a power electrode), and a silver paste film is used as the first electrode (<NUM>: a ground electrode). In the reactor <NUM>, a discharge region having a length of <NUM> is surrounded by the ground electrode. A discharge gap between the inner surface of the quartz tube and a high voltage electrode that is the second electrode <NUM> is <NUM>. At this time, the volume of the plasma discharge region is fixed to <NUM><NUM>. The plurality of dielectric particles <NUM> are completely filled in the packed-bed <NUM> provided in the plasma discharge region. At this time, the plurality of dielectric particles <NUM> are spherical glass particles having a diameter of <NUM>, and the porosity of the packed-bed <NUM> is <NUM>%. Water (H<NUM>O) is used a liquid supplied into the reactor <NUM> and is sprayed at a volume flow rate of <NUM>/min. A sinusoidal AC power supply is connected to a transformer, and a high voltage is continuously applied to the plasma discharge region through this electrical system. The voltage applied to the plasma discharge region changes from <NUM> kV to <NUM> kV, and in this regard, an electric field changes from <NUM> kV/cm to <NUM> kV/cm. The purified air outlet <NUM> measures a residual ratio of ammonia (NH<NUM>), acetaldehyde (CH<NUM>CHO), and acetic acid (CH<NUM>COOH).

Referring to <FIG>, it may be seen that ammonia (NH<NUM>) is completely removed from a first region Area <NUM> in which a voltage equal to or less than <NUM> kV is applied to the plasma discharge region. That is, ammonia (NH<NUM>) is removed to the liquid recoverer <NUM> by water (H<NUM>O) supplied into the reactor <NUM>. It may be seen that more than <NUM>% of acetaldehyde (CH<NUM>CHO) and acetic acid (CH<NUM>COOH) is also removed from the first region Area <NUM> in which the voltage equal to or less than <NUM> kV is applied to the plasma discharge region. It may be seen that the remaining substances among acetaldehyde (CH<NUM>CHO) and acetic acid (CH<NUM>COOH) are decomposed into carbon dioxide (CO<NUM>) and water (H<NUM>O) and removed in a second region Area to which a high voltage equal to or higher than <NUM> kV is applied. Therefore, it may be seen that most of the water soluble organic compound VOCsol is collected by the liquid and is primarily removed. It may be seen that the remaining water soluble organic compound VOCsol is decomposed by the high voltage applied to the plasma discharge region and removed.

When a ratio of ammonia (NH<NUM>) having a high solubility to the liquid is high, the time when the water soluble organic compound VOCsol remains in the reactor <NUM> need to be improved. To this end, an average diameter of the plurality of dielectric particles <NUM> may be reduced such that a porosity inside the packed-bed <NUM> may be reduced.

Meanwhile, when a ratio of acetaldehyde (CH<NUM>CHO) and acetic acid (CH<NUM>COOH) having a relatively low solubility to the liquid is high, the removal efficiency of water soluble organic compounds VOCsol may be improved by increasing the voltage applied to the plasma discharge region(i.e., the packed-bed <NUM>). For example, the controller <NUM> may generate a control signal with respect to the high voltage generator <NUM> to increase the magnitude of voltage generated by the high voltage generator <NUM>, thereby improving the removal efficiency of the water soluble organic compound VOCsol.

<FIG> is a graph showing plasma voltage and removal efficiency of the water insoluble organic compound (VOCinsol) according to an embodiment and a comparative example.

Except for a type and volume flow rate of contaminated air supplied to the reactor <NUM> and a volume flow rate of a liquid, the remaining experimental methods are the same as in Experimental Example <NUM>.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol flowing into the reactor <NUM> is toluene (C<NUM>H<NUM>CH<NUM>) of <NUM> ppm, and the volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) is <NUM>/min. No liquid flows into the reactor <NUM>.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol flowing into the reactor <NUM> is toluene (C<NUM>H<NUM>CH<NUM>) of <NUM> ppm, and the volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) is <NUM>/min. The liquid flowing into the reactor <NUM> is water (H<NUM>O), and the volume flow rate thereof is <NUM>/min.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol flowing into the reactor <NUM> is toluene (C<NUM>H<NUM>CH<NUM>) of <NUM> ppm, and the volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) is <NUM>/min. The liquid flowing into the reactor <NUM> is water (H<NUM>O), and the volume flow rate is <NUM>/min.

Referring to <FIG>, in Experimental Examples <NUM>-<NUM> to <NUM>-<NUM>, it may be seen that a removal rate of toluene (C<NUM>H<NUM>CH<NUM>) increases as a voltage increases to <NUM> kV in a plasma discharge region. However, toluene (C<NUM>H<NUM>CH<NUM>) is removed according to the voltage applied to the plasma discharge region regardless of the volume flow rate of water (H<NUM>O)) supplied to the reactor <NUM>. Accordingly, it may be seen that the water insoluble organic compound VOCinsol remains regardless of the flow rate of the liquid supplied to the reactor <NUM>.

In addition, in Experimental Examples <NUM>-<NUM> to <NUM>-<NUM>, it may be seen that the removal rate of toluene (C<NUM>H<NUM>CH<NUM>) increases as the voltage rises to <NUM> kV in the plasma discharge region. However, compared to Experimental Examples <NUM>-<NUM> to <NUM>-<NUM>, as the volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) increases, the time when toluene (C<NUM>H<NUM>CH<NUM>) remains in the reactor <NUM> may be reduced. Accordingly, it may be seen that only about <NUM>% of toluene (C<NUM>H<NUM>CH<NUM>) is removed even when the voltage rises to <NUM> kV in the plasma discharge region.

As described above, when the time when toluene (C<NUM>H<NUM>CH<NUM>) remains in the reactor <NUM> is reduced as the volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) increases, in order to completely remove toluene (C<NUM>H<NUM>CH<NUM>), the time when toluene (C<NUM>H<NUM>CH<NUM>) remains in the reactor <NUM> needs to increase. For example, by reducing the volume flow rate of toluene (C<NUM>H<NUM>CH<NUM>) supplied to the reactor <NUM>, or by reducing a porosity inside the packed bed <NUM>, the time when toluene (C<NUM>H<NUM>CH<NUM>) remains in the reactor <NUM> may increase. In the above-described embodiment, the contaminated air Air<NUM> each including the fine dust PM, the water soluble organic compound VOCsol, and the water insoluble organic compound VOCinsol is described, but the air purification device <NUM> according to an embodiment may purify the contaminated air Air<NUM> including two or more of the fine dust PM, the water soluble organic compound VOCsol, and the water insoluble organic compound VOCinsol.

<FIG> is a graph showing plasma voltage and removal efficiency of fine dust according to an embodiment;.

At atmospheric pressure and a temperature close to room temperature, reaction between the fine dust PM and the water insoluble organic compound VOCinsol is carried out using the air purification device <NUM>.

A volume flow rate of a mixture of the fine dust PM and contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) of <NUM> ppm that is the water insoluble organic compound VOCinsol is <NUM>/min. As a dielectric barrier of the reactor <NUM>, a quartz tube having an inner diameter of <NUM> and a thickness of <NUM> is used A stainless steel rod of a <NUM> diameter is used as a second electrode (<NUM>: a power electrode), and a silver paste film is used as the first electrode (<NUM>: a ground electrode). In the reactor <NUM>, a discharge region having a length of <NUM> is surrounded by the ground electrode. A discharge gap between the inner surface of a glass tube and a high voltage electrode that is the second electrode <NUM> is <NUM>. At this time, the volume of the plasma discharge region is fixed to <NUM><NUM>. The plurality of dielectric particles <NUM> are completely filled in the packed-bed <NUM> provided in the plasma discharge region(i.e., the packed-bed <NUM>). At this time, the plurality of dielectric particles <NUM> are spherical glass particles having a diameter of <NUM>, and the porosity of the packed-bed <NUM> is <NUM>%. A liquid supplied to the inside of the reactor <NUM> is a sodium hydroxide (NaOH) aqueous solution having a concentration of <NUM> mmol/L and PH11, and is sprayed at a volume flow rate of <NUM>/min. A DC pulsed power supply is connected to the reactor <NUM>, and a high voltage is continuously applied to a plasma discharge region through this electrical system.

In Experimental Example <NUM>-<NUM>, the voltage applied to the plasma discharge region(i.e., the packed-bed <NUM>) is <NUM> kV, and a frequency is <NUM>. In Experimental Example <NUM>-<NUM>, the voltage applied to the plasma discharge region is <NUM> kV and the frequency is <NUM>. In Experimental Example <NUM>-<NUM>, the voltage applied to the plasma discharge region is <NUM> kV and the frequency is <NUM>. Regarding Experimental Examples <NUM>-<NUM> to <NUM>-<NUM>, the purified air outlet <NUM> measures the fine dust PM, a residual ratio of toluene (C<NUM>H<NUM>CH<NUM>) and a generation concentration of ozone (O<NUM>).

In Experimental Example <NUM>-<NUM>, the fine dust PM is removed by an average of <NUM>% or more, and toluene (C<NUM>H<NUM>CH<NUM>) is removed by <NUM>% or more. Meanwhile, ozone (O<NUM>) of <NUM> ppm is generated.

Referring to Experimental Examples <NUM>-<NUM> to <NUM>-<NUM>, it may be seen that the removal rate of the fine dust PM and toluene (C<NUM>H<NUM>CH<NUM>) increases as the voltage applied to the plasma discharge region(i.e., the packed-bed <NUM>) increases. However, it may be seen that oxygen (O<NUM>) is decomposed during a plasma discharge process and thus a generation amount of ozone (O<NUM>) increases. In order to remove contaminated air, the voltage applied to the plasma discharge region may increase, but the generation amount of ozone (O<NUM>) also needs to be reduced. To this end, the alkaline strength PH of the liquid flowing into the reactor <NUM> may be adjusted.

<FIG> is a graph showing a relationship between a plasma voltage and a concentration of ozone (O<NUM>) according to an embodiment and a comparative example.

At atmospheric pressure and a temperature close to room temperature, reaction of the water insoluble organic compound VOCinsol is carried out using the air purification device <NUM>.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol is toluene (C<NUM>H<NUM>CH<NUM>) having a concentration of <NUM> ppm, and a volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) is <NUM>/min. As a dielectric barrier of the reactor <NUM>, a glass tube having an inner diameter of <NUM> and a thickness of <NUM> is used. A stainless steel rod of a <NUM> diameter is used as a second electrode (<NUM>: a power electrode), and a silver paste film is used as the first electrode (<NUM>: a ground electrode). In the reactor <NUM>, a discharge region having a length of <NUM> is surrounded by the ground electrode. A discharge gap between the inner surface of the quartz tube and a high voltage electrode that is the second electrode <NUM> is <NUM>. At this time, the volume of the plasma discharge region is fixed to <NUM><NUM>. The plurality of dielectric particles <NUM> are completely filled in the packed-bed <NUM> provided in the plasma discharge region. At this time, the plurality of dielectric particles <NUM> are spherical glass particles having a diameter of <NUM>, and the porosity of the packed-bed <NUM> is <NUM>%. No liquid is supplied into the reactor <NUM>. A voltage applied to the plasma discharge region changes, and a frequency is <NUM>.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol is toluene (C<NUM>H<NUM>CH<NUM>) having a concentration of <NUM> ppm, and the volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) is <NUM>/min. Water (H<NUM>O) having a volume flow rate of <NUM>/min is supplied into the reactor <NUM>. The remaining configuration is the same as in Experimental Example <NUM>-<NUM>.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol is toluene (C<NUM>H<NUM>CH<NUM>) having a concentration of <NUM> ppm, and the volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) is <NUM>/min. Hydroxide (NaOH) aqueous solution having a volume flow rate of <NUM>/min and a molar concentration of <NUM> mmol/L is supplied into the reactor <NUM>. The remaining the configuration is the same as in Experimental Example <NUM>-<NUM>.

Referring to Experimental Example <NUM>-<NUM>, it may be seen that a concentration of ozone (O<NUM>) increases even at the lowest discharge plasma voltage. Referring to Experimental Example <NUM>-<NUM>, it may be seen that at a discharge plasma voltage higher than that of Experimental Example <NUM>-<NUM>, the concentration of ozone (O<NUM>) increases similarly to Experimental Example <NUM>-<NUM>.

Referring to Experimental Example <NUM>-<NUM>, it may be seen that the concentration of ozone (O<NUM>) increases at a discharge plasma voltage higher than that of Experimental Example <NUM>-<NUM>, and the concentration of ozone (O<NUM>) remains lower than that of Experimental Example <NUM>-<NUM>. Referring to Experimental Example <NUM>-<NUM>, it may be seen that the concentration of ozone (O<NUM>) increases at a discharge plasma voltage higher than that of Experimental Example <NUM>-<NUM>, and the concentration of ozone (O<NUM>) remains lower than that of Experimental Example <NUM>-<NUM>.

When the plasma discharge voltage increases in the air purification device <NUM> according to an embodiment, a removal rate of the water insoluble organic compound VOCinsol may increase. Meanwhile, when the plasma discharge voltage increases, the concentration of ozone (O<NUM>) may increase during a process of decomposing oxygen (O<NUM>). As in Experimental Examples <NUM>-<NUM> to <NUM>-<NUM>, it may be seen that when the alkaline strength (PH) of the liquid supplied to the reactor <NUM> increases, an increase in the concentration of ozone (O<NUM>) may be suppressed. Accordingly, the plasma discharge voltage may increase as the volume flow rate and a degree of contamination of the contaminated air Air<NUM> increase, and at this time, when the alkaline strength (PH) of the liquid supplied to the reactor <NUM> increases, not only the contaminated air Air<NUM> may be purified but also a generation of ozone (O<NUM>) may be suppressed.

<FIG> are graphs showing changes in a toluene concentration and an ozone concentration according to an experimental example.

At atmospheric pressure and a temperature close to room temperature, a reaction of the water insoluble organic compound VOCinsol is carried out using the air purification device <NUM>.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol is toluene (C<NUM>H<NUM>CH<NUM>) having a concentration of <NUM> ppm, and a volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) is <NUM>/min. As a dielectric barrier of the reactor <NUM>, a glass tube having an inner diameter of <NUM> and a thickness of <NUM> is used. A stainless steel rod of a <NUM> diameter is used as a second electrode (<NUM>: a power electrode), and a silver paste film is used as the first electrode (<NUM>: a ground electrode). In the reactor <NUM>, a discharge region having a length of <NUM> is surrounded by the ground electrode. A discharge gap between the inner surface of the quartz tube and a high voltage electrode that is the second electrode <NUM> is <NUM>. At this time, the volume of the plasma discharge region is fixed to <NUM><NUM>. The plurality of dielectric particles <NUM> are completely filled in the packed-bed <NUM> provided in the plasma discharge region. At this time, the plurality of dielectric particles <NUM> are spherical alumina particles having a diameter of <NUM>, and the porosity of the packed-bed <NUM> is <NUM>%. No liquid is supplied into the reactor <NUM>. A voltage applied to the plasma discharge region changes, and a frequency is <NUM>.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol flowing into the reactor <NUM> is toluene (C<NUM>H<NUM>CH<NUM>) of <NUM> ppm, and the volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) is <NUM>/min. A liquid flowing into the reactor <NUM> is water (H<NUM>O), and the volume flow rate thereof is <NUM>/min. The remaining configuration is the same as in Experimental Example <NUM>-<NUM>.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol flowing into the reactor <NUM> is toluene (C<NUM>H<NUM>CH<NUM>) of <NUM> ppm, and the volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) is <NUM>/min. No liquid flows into the reactor <NUM>. A reactor filled with a manganese dioxide (MnO2) catalyst is connected to a rear end of the reactor, and a volume of the filled manganese dioxide catalyst is <NUM><NUM>. The remaining configuration is the same as in Experimental Example <NUM>-<NUM>.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol flowing into the reactor <NUM> is toluene (C<NUM>H<NUM>CH<NUM>) of <NUM> ppm, and the volume flow rate of contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) is <NUM>/min. A liquid flowing into the reactor <NUM> is water (H<NUM>O), and the volume flow rate thereof is <NUM>/min. The reactor filled with a manganese dioxide (MnO2) catalyst is connected to the rear end of the reactor, and the volume of the filled manganese dioxide catalyst is <NUM><NUM>. The remaining configuration is the same as in Experimental Example <NUM>-<NUM>.

In Experimental Example <NUM>-<NUM>, a toluene removal rate is <NUM>%, and the ozone concentration is <NUM> pppm.

In Experimental Example <NUM>-<NUM>, the toluene removal rate is <NUM>%, and the ozone concentration is <NUM> ppm.

In Experimental Example <NUM>-<NUM>, the toluene removal rate is <NUM>%, and the ozone concentration is less than <NUM> ppm.

Referring to Experimental Examples <NUM>-<NUM> to <NUM>-<NUM>, it may be seen that the ozone concentration may be reduced to less than 1ppm by introducing an ozone removal catalyst such as manganese dioxide (MnO2). At this time, it may be seen that the presence or absence of an inflow liquid does not affect the ozone removal performance of the catalyst.

<FIG> are graphs showing changes in a toluene concentration and an ozone concentration according to experimental examples.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol is toluene (C<NUM>H<NUM>CH<NUM>) having a concentration of <NUM> ppm, and a volume flow rate of a mixture including contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) and the find dust PM is <NUM>/min. No liquid is supplied into the reactor <NUM>. A reactor filled with a manganese dioxide (MnO2) catalyst is connected to a rear end of the reactor, and a volume of the filled manganese dioxide catalyst is <NUM><NUM>. The remaining configuration is the same as in Experimental Example <NUM>-<NUM>.

In Experimental Example <NUM>-<NUM>, the water insoluble organic compound VOCinsol is toluene (C<NUM>H<NUM>CH<NUM>) having a concentration of <NUM> ppm, and the volume flow rate of the mixture including contaminated air including toluene (C<NUM>H<NUM>CH<NUM>) and the find dust PM is <NUM>/min. A liquid flowing into the reactor <NUM> is water (H<NUM>O), and the volume flow rate thereof is <NUM>/min. The reactor filled with a manganese dioxide (MnO2) catalyst is connected to the rear end of the reactor, and the volume of the filled manganese dioxide catalyst is <NUM><NUM>. The remaining configuration is the same as in Experimental Example <NUM>-<NUM>.

In Experimental Example <NUM>-<NUM>, the fine dust PM is removed by an average of <NUM>% or more, and toluene (C<NUM>H<NUM>CH<NUM>) is removed by <NUM>% or more. A generation amount of ozone (O<NUM>) is less than <NUM> ppm.

In Experimental Example <NUM>-<NUM>, the fine dust PM is removed by an average of <NUM>% or more, and toluene (C<NUM>H<NUM>CH<NUM>) is removed by <NUM>% or more. The generation amount of ozone (O<NUM>) is less than <NUM> ppm.

Referring to Experimental Examples <NUM>-<NUM> to <NUM>-<NUM>, it may be seen that even when the fine dust PM and toluene (C<NUM>H<NUM>CH<NUM>) are supplied simultaneously, an ozone removal catalyst such as manganese dioxide (MnO2) is introduced to reduce the ozone concentration to less than <NUM> ppm.

<FIG> is a flowchart of an air purification method according to an embodiment.

Referring to <FIG> and <FIG>, a liquid may flow into the reactor <NUM> according to an embodiment. (S110) As an example, the reactor <NUM> may have a flow path through which the liquid and the contaminated air Air<NUM> may move. In this regard, the liquid may be water or a basic aqueous solution.

Next, a discharge plasma may be generated by applying a certain voltage to the first electrode <NUM> and the second electrode <NUM>. (S120) As an example, the first electrode <NUM> may be disposed on an outer wall of the reactor <NUM> as a ground electrode, and the second electrode <NUM> may be disposed inside the reactor <NUM> as a power electrode. In this regard, the first electrode <NUM> and the second electrode <NUM> may be spaced apart from each other with a certain distance therebetween. By applying the certain voltage to the first electrode <NUM> and the second electrode <NUM>, the discharge plasma is generated in the packed-bed <NUM>. In this regard, a magnitude of the voltage applied to the first electrode <NUM> and the second electrode <NUM> may be controlled through the controller <NUM>.

Next, the contaminated air Air<NUM> may flow into the reactor <NUM>. (S130) As an example, the contaminated air Air<NUM> may be a mixture gas including at least one of the fine dust PM, the water soluble organic compound VOCsol, and the water insoluble organic compound VOCinsol. A volume flow rate of the contaminated air Air<NUM> may increase or decrease according to a purification capability of the air purification device <NUM>. The contaminated air Air<NUM> flowing into the reactor <NUM> may be collected by the liquid or decomposed into carbon dioxide (CO<NUM>) and water (H<NUM>O) by plasma.

Next, ozone may be removed by using a catalyst at a rear end of the reactor <NUM>. (S140) As an example, the catalyst included in the catalyst reactor <NUM> may include at least one of manganese oxide, copper oxide, and aluminum oxide, or at least one of mixtures between the substances.

Next, the liquid and purified air may be discharged from the reactor <NUM>. (S150) According to an embodiment, the liquid obtained by collecting part of the contaminated air Air<NUM> and purified air Air<NUM> obtained by decomposing part of the contaminated air Air<NUM> may be discharged to the outside of the reactor <NUM>.

The liquid obtained by collecting the part of the contaminated air Air<NUM> may be stored in the liquid recoverer <NUM>. The liquid stored in the liquid recoverer <NUM> may move to the liquid supplier <NUM> using the pump <NUM> after removing the contaminated air Air<NUM> using a purification device. Accordingly, the liquid supplier <NUM> may reuse purified water or a basic aqueous solution.

According to the above-described embodiments of the air purification device and air purification method, fine dust and a contaminant are ionized or decomposed by a discharge plasma, and may be easily discharged from a reactor after collected in a liquid passing through a reactor. Therefore, the fine dust and the contaminant in the air are more easily collected in the liquid and discharged to the outside, and thus an excellent contaminant removal performance may be implemented. In addition, the liquid in which the fine dust and the contaminant are collected is easily discharged from the reactor, and thus the burden of periodic management or replacement of the reactor may be reduced.

The embodiments of the air purification device and the air purification method have been described with reference to the drawings for better understanding, but this is only exemplary, and it will be understood by those of ordinary skill in the art that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present disclosure should be determined by the appended claims.

Claim 1:
An air purification device (<NUM>) comprising:
a reactor (<NUM>) having a hollow shape and extending in one direction;
a discharge plasma generator (<NUM>) comprising a first electrode (<NUM>) disposed on an outer wall of the reactor and a second electrode (<NUM>) disposed inside the reactor, wherein the discharge plasma generator is configured to generate a discharge plasma in a certain discharge region;
a plurality of dielectric particles (<NUM>) disposed on a packed-bed (<NUM>) of the reactor, wherein the discharge region includes the packed-bed;
a liquid supplier (<NUM>) configured to supply a liquid into the reactor, and to spray the liquid to the packed-bed; and
a liquid recoverer (<NUM>) configured to recover the liquid discharged from the reactor.