WO2022035088A1 - Plasma catalyst reactor for removing harmful gas and method of treating harmful gas by using same - Google Patents

Abstract

The present invention relates to a plasma catalyst reactor for removing harmful gas, and a method of treating harmful gas by using same, and more specifically, to a plasma catalyst reactor for removing harmful gas, and to a method of treating harmful gas by using same, which can achieve a maximum energy-saving effect and large-volume harmful gas processing efficiency at a low cost, by applying a humidified metal-loaded monolithic substrate to the plasma catalyst reactor, thereby stably generating an atmospheric-pressure low-temperature plasma based on corona discharge within the monolithic substrate.

Description

Plasma catalyst reactor for removing harmful gas and method for treating harmful gas using the same

The present invention relates to a plasma catalyst reactor for removing harmful gases and a method for treating harmful gases using the same. It relates to a plasma catalytic reactor for use and a method for treating harmful gases using the same.

In general, odors, volatile organic compounds (VOC), perfluorinated compounds (PFC, CFC), chlorine and cyanide compounds, dioxins, NO _x , SO _x emitted from industrial sites or daily life are very dangerous to the human body as well as However, since it can pollute the global environment and destroy the ecosystem, the emission regulations are being strengthened worldwide.

Incineration, catalyst, adsorption, or biological treatment methods are used to treat such harmful gases, but there are problems such as high cost for treatment or poor treatment efficiency.

Toxic gas treatment method using low-temperature plasma catalyst is a method that many studies are being conducted to improve the existing high-cost treatment method. Basically, a harmful gas treatment catalyst is inserted between two opposite electrodes and the It is a technology that supplies a voltage to generate a discharge composed of electrons, ions, and radicals, and at the same time treats harmful gases using a catalyst for treating harmful gases.

There are basically bed-needle, bed-plate, flat-to-plate, and flat-to-wire methods in the shape of electrodes for generating plasma, and depending on the barrier design method for stable plasma discharge without reaching arc discharge, the charging layer ( It can be divided into a Packed Bed) discharge method and a Dielectric Barrier Discharge (DBD) method.

A packed bed discharge type plasma catalyst reactor is a plasma catalyst reactor in which a pellet catalyst is filled between both electrodes, and most studies of plasma catalyst reactors are being conducted based on the packed bed method.

Noxious gas treatment using a catalytic reaction inevitably requires contact between the noxious gas and the catalyst. Accordingly, in the packed bed discharge type plasma catalyst reactor, the distance between the high voltage electrode and the ground electrode increases as much as the distance the catalyst is filled, and a large amount of high energy must be consumed to stably generate plasma. As a result, there are problems in the generation of nitrogen oxides and a large amount of ozone from the air, as well as the problem that the concentration of harmful gas to be treated is limited depending on the amount of catalyst, which is not practical. The reactor had to be coupled, and there was a problem in that the operating cost was increased due to the high pressure drop across the packed bed.

In order to overcome the shortcomings of such a packed-bed discharge type plasma catalytic reactor, a dielectric barrier type plasma catalytic reactor that generates plasma of a uniform volume by inserting one or more dielectrics between a high voltage electrode and a ground electrode has recently been developed. In the case of a barrier type plasma catalytic reactor, the dielectric applied to the dielectric barrier type plasma catalytic reactor is made of quartz, ceramic, etc. and can be easily cracked due to thermal shock or mechanical shock. There was a problem.

On the other hand, the current research on conventional plasma catalyst using a honeycomb monolithic carrier mostly stays at the level of connecting a plasma reactor and a catalyst reactor in series or arranging a plasma and a catalyst reactor alternately [Korea Patent No. 0543529 (Korean Patent No. 0543529) Publication date: January 31, 2006), Korean Patent Application Laid-Open No. 2007-0001387 (published on January 4, 2007), Plasma Catalysis: Fundamentals and Applications, Springer International Publishing, Cham, 2019, 21-46, Plasma Chem. Plasma Process, 36, 45-72, J. Adv. Oxid. Technol., 2003, 158].

As an example, looking at non-patent document 0003 disclosing a two-step plasma catalyst system for nitrogen oxide treatment, a part of NO is oxidized to NO ₂ by various oxidative species generated through plasma discharge, and the optimal The NO/NO ₂ ratio of is provided to the downstream catalytic reactor. In addition, when hydrocarbons are used as a reducing agent for nitrogen oxides, various oxygen-containing hydrocarbons having excellent reducing ability are formed by plasma discharge, thereby improving low-temperature catalytic activity. At this time, plasma generates various reactive species (radicals, ozone, etc.), but active reactive species other than ozone have a very short lifespan, making it difficult to apply them in a wide space.

Therefore, in these two-stage plasma catalyst systems, short-lived reactive species disappear before reaching the catalytic reactor and are not directly involved in the catalytic reaction. Should be. In other words, it is desirable to generate the plasma inside the monolith carrier so that the plasma can directly affect the catalyst.

However, in the case of a commercially manufactured honeycomb monolith carrier, the height is 5 cm or more and the width (diameter) is 9 cm or more. As a result, there was a problem in that it was difficult to generate a low-temperature plasma inside the monolith.

The main object of the present invention is to solve the above problems, and to provide a plasma catalytic reactor for removing harmful gases and a method for treating harmful gases using the same, which can obtain maximum energy saving effect and large-capacity harmful gas treatment efficiency at low cost .

In order to achieve the above object, an embodiment of the present invention, a perforated plate-shaped high voltage electrode; a perforated plate-shaped ground electrode positioned to face and spaced apart from the high voltage electrode; a monolithic carrier on which a catalytically active metal is supported, which is located between the high voltage electrode and the ground electrode and contains moisture; and a power supply unit for applying an AC voltage to the high voltage electrode, wherein the AC voltage is applied to the high voltage electrode by the power supply unit to generate plasma inside the monolith carrier by corona discharge, and harmful gas to the plasma region It provides a plasma catalyst reactor for removing harmful gases, characterized in that introduced and discharged.

Another embodiment of the present invention, a perforated plate-shaped high voltage electrode; a perforated plate-shaped ground electrode positioned to face and spaced apart from the high voltage electrode; a monolithic carrier positioned between the high voltage electrode and the ground electrode and on which a catalytically active metal is supported; a monolith guard unit disposed between the high voltage electrode and the monolith carrier to prevent arc generation; and a power supply unit for applying a voltage to the high voltage electrode, wherein a voltage is applied to the high voltage electrode by the power supply unit to generate plasma inside the monolith carrier by corona discharge, and harmful gas is introduced into the plasma region It provides a plasma catalytic reactor for removing harmful gas, characterized in that discharged.

Another embodiment of the present invention, a high voltage electrode in the shape of a perforated plate; a perforated plate-shaped ground electrode positioned to face and spaced apart from the high voltage electrode; a monolithic carrier on which a catalytically active metal is supported, which is located between the high voltage electrode and the ground electrode and contains moisture; and a power supply unit for applying a positive (+) polarity DC voltage to the high voltage electrode, wherein a DC voltage is applied to the high voltage electrode by the power supply unit to generate plasma inside the monolith carrier by corona discharge, and harmful gas It provides a plasma catalyst reactor for removing harmful gas, characterized in that introduced into the plasma region and discharged.

In a preferred embodiment of the present invention, the monolithic carrier may have a width of 9 cm or more and/or a height of 5 cm or more.

In a preferred embodiment of the present invention, the ground electrode is spaced apart from the monolith carrier by 2 mm or less, and may be characterized in that it is positioned behind the monolith carrier through which harmful gases are discharged.

In a preferred embodiment of the present invention, the high voltage electrode is spaced apart from the monolith carrier by 1 mm to 10 mm, and may be characterized in that it is positioned in front of the monolith carrier into which noxious gas is introduced.

In a preferred embodiment of the present invention, the monolith carrier may have a honeycomb shape, and the monolith guard part may have a honeycomb shape.

In a preferred embodiment of the present invention, the monolith guard unit may be characterized as a monolith having an electrical resistance of 16 MΩ or more.

In a preferred embodiment of the present invention, the harmful gas is at least one selected from the group consisting of odor, volatile organic compounds, nitrogen compounds, sulfur oxides, fluorine compounds, chlorine compounds, cyanide compounds, carbon monoxide, carbon dioxide and dioxins. can be done with

In a preferred embodiment of the present invention, the plasma catalytic reactor may be characterized in that two or more monolithic carriers are arranged in series.

Another embodiment of the present invention provides a noxious gas treatment method, characterized in that the noxious gas is treated using the plasma catalyst reactor for removing the noxious gas, and the relative humidity in the noxious gas is less than 100 vol%.

According to the present invention, by applying a pre-humidified metal-supported monolithic carrier to a plasma catalytic reactor to stably generate a corona discharge-based atmospheric low-temperature plasma inside the monolithic carrier, without the use of a monolithic carrier customized to a size for plasma catalysis Commercially available monolithic carrier can be applied, and a large amount of harmful gas can be effectively treated using plasma reaction and catalyst without pressure drop of the catalyst, and the maximum voltage applied to the driving electrode is lowered for reactor operation efficiency and stability can be improved at the same time. In addition, it is possible to quickly respond to the applied voltage, thereby increasing the efficiency of the catalyst.

In addition, the plasma catalytic reactor according to the present invention can receive the reaction energy required for the treatment of harmful gases using the catalyst from the low-temperature plasma, so there is an effect that harmful gas treatment is possible without the need for additional heating or energy supply for the catalytic reaction.

1 is a schematic perspective view of a plasma catalytic reactor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the plasma catalytic reactor shown in FIG. 1 .

3 is a schematic perspective view of a plasma catalytic reactor according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view of the plasma catalytic reactor shown in FIG. 3 .

5 is a schematic experimental setup diagram for measuring the performance of a plasma catalytic reactor according to an embodiment of the present invention.

6 is a photograph of plasma generation in the plasma catalytic reactor of Example 1 (a) and the plasma catalytic reactor of Comparative Example 10 (b) of the present invention.

7 is a graph showing the results of measuring the discharge power over time in the plasma catalyst reactor according to Examples 1 to 7 of the present invention.

8 is a graph showing the result of measuring the discharge power over time in the plasma catalyst reactor according to Comparative Examples 1 to 7 of the present invention.

9 is a graph showing the results of measuring the discharge power over time in the plasma catalyst reactor according to Comparative Examples 8 and 9 of the present invention.

10 is a graph showing the results of measuring the toluene concentration for each hour after treatment in the plasma catalytic reactor according to Example 8 and Comparative Example 12 of the present invention, (a) is a measurement of the toluene concentration change and adsorption capacity at the outlet for 250 minutes It is a graph, and (b) is the change in toluene concentration at the outlet for 700 minutes.

11 is a graph showing the result of measuring the discharge power for each voltage in the plasma catalyst reactor according to Examples 9 to 12 of the present invention.

12 is a graph showing the result of measuring the discharge power for each voltage in the plasma catalytic reactor according to the presence or absence of the monolith guard unit of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is those well known and commonly used in the art.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "include" or "have" are intended to designate that the features, components, etc. described in the specification are present, and one or more other features or components may not be present or may be added. Doesn't mean there isn't.

The present invention, in one aspect, a perforated plate-shaped high voltage electrode; a perforated plate-shaped ground electrode positioned to face and spaced apart from the high voltage electrode; a humidified monolithic carrier positioned between the high voltage electrode and the ground electrode and containing a catalytically active metal; and a power supply unit for applying an alternating voltage to the high voltage electrode, wherein a voltage is applied to the high voltage electrode by the power supply unit to generate plasma inside the monolithic carrier humidified by corona discharge, and harmful gas is generated in the plasma region It relates to a plasma catalytic reactor for removing harmful gas, characterized in that it is injected and discharged.

In another aspect, the present invention provides a perforated plate-shaped high voltage electrode; a perforated plate-shaped ground electrode positioned to face and spaced apart from the high voltage electrode; a monolithic carrier positioned between the high voltage electrode and the ground electrode and on which a catalytically active metal is supported; a monolith guard unit disposed between the high voltage electrode and the monolith carrier to prevent arc generation; and a power supply unit for applying a voltage to the high voltage electrode, wherein a voltage is applied to the high voltage electrode by the power supply unit to generate plasma inside the monolith carrier by corona discharge, and harmful gas is introduced into the plasma region It relates to a plasma catalytic reactor for removing harmful gas, characterized in that it is discharged.

In another aspect, the present invention, a perforated plate-shaped high-voltage electrode; a perforated plate-shaped ground electrode positioned to face and spaced apart from the high voltage electrode; a monolithic carrier on which a catalytically active metal is supported, which is located between the high voltage electrode and the ground electrode and contains moisture; and a power supply unit for applying a positive (+) polarity DC voltage to the high voltage electrode, wherein a DC voltage is applied to the high voltage electrode by the power supply unit to generate plasma inside the monolith carrier by corona discharge, and harmful gas It relates to a plasma catalyst reactor for removing harmful gases, characterized in that introduced into the plasma region and discharged.

Hereinafter, with reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

1 is a schematic perspective view illustrating a plasma catalytic reactor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the plasma catalytic reactor shown in FIG. 1 , and FIG. 3 is a plasma catalyst according to another embodiment of the present invention. It is a schematic perspective view illustrating a reactor, and FIG. 4 is a cross-sectional view of the plasma catalyst reactor shown in FIG. 3 .

The plasma catalytic reactor 100 according to the present invention is used to remove harmful gases by being installed in various mechanical devices and mechanical facilities that generate harmful gases such as automobiles, plants, and power plants. In this case, the harmful gas can be applied without limitation as long as it is a gas harmful to the human body, and may be a volatile organic compound, a nitrogen-based compound, a sulfur oxide, a fluorine compound, a chlorine compound, a cyanide compound, carbon monoxide, carbon dioxide, a dioxin, an odor, and the like.

1 to 4, the plasma catalytic reactor 100 according to an embodiment of the present invention includes a monolithic carrier 110 on which a catalytically active metal is supported to remove harmful gases by passing harmful gases therein, the monolith It includes a high voltage electrode 120 positioned in front of the carrier 110 and a ground electrode 130 positioned in the rear of the monolith carrier. Here, the front side of the monolithic carrier means the side through which noxious gas is introduced, and the rear side of the monolithic carrier refers to the side through which the noxious gas exits.

The monolithic carrier, the high voltage electrode, and the ground electrode may be surrounded by the housing 140 . The housing 140 is connected to a pipe for discharging noxious gas among the aforementioned mechanical devices or mechanical equipment, and provides a space through which the noxious gas flows, and on the other hand, the chamber may be formed of a pipe itself. That is, the above-described high voltage electrode 120 , the monolithic carrier 110 , and the ground electrode 130 may be installed inside the pipe through which the harmful gas flows. In this case, the housing 140 may be formed of an insulating material, or an insulating layer may be formed in a region surrounding the high voltage electrode, the monolithic carrier, and the ground electrode in the pipe.

The monolith carrier 110 includes a catalytically active metal (not shown) supported on its surface by a known method such as coating, impregnation, and ion exchange, and in order to reduce pressure loss during injection and discharge of harmful gases. It may be formed in various shapes having a channel structure open in the direction of both ends, and may preferably be a honeycomb shape having a honeycomb-shaped channel. In this case, in the specification, the height of the monolith carrier is referred to as the length of the axis connecting both open ends in a straight line, and the length perpendicular to the height is referred to as the width (diameter).

The monolith carrier 110 can be applied without limitation as long as it is a material applicable to a typical catalyst carrier for removing harmful gases, but in terms of hygroscopicity, plasma resistance and heat resistance ZrO ₂ , Al ₂ O ₃ , zeolite, alumina nitride Inorganic such as , mullite, steatite, forsterite, cordierite, magnesium titanate, barium titanate, SiC, Si ₃ N ₄ , Si-SiC, mica, glass, etc. It can be a material.

In the case of such inorganic materials such as alumina and glass, they have dielectric constants of 10 and 5, but in the case of inorganic materials containing moisture, they have a high dielectric constant of 40 to 50. can be applied and a structure that is easy to generate plasma by corona discharge can be made.

In addition, the monolith carrier according to the present invention contains moisture on the surface and inside the monolith carrier so that corona discharge is easily generated inside the monolith carrier channel.

The plasma catalytic reactor to which the conventional monolithic carrier is applied has an advantage in that it can process harmful gases without pressure loss compared to the plasma catalytic reactor to which the pellet-shaped carrier is applied. Since only the carrier can be applied, the processing capacity of harmful gas is small, and there is a problem in that no plasma is generated inside the monolith carrier, so there is a problem that the harmful gas treatment efficiency is lowered.

Accordingly, the plasma catalytic reactor according to the present invention can easily generate and propagate plasma along the open channel of the monolith carrier by pre-containing moisture on the surface of the monolith carrier, the inside of the channel, etc., and thus has a width of 9 cm or more, and a height Plasma can be easily generated even on a commercial monolithic carrier that forms a long straight channel of 5 cm or more, and it has a fast response speed to the voltage application of the monolith. Since the catalytic reaction can be performed at the same time, a large amount of harmful gas can be easily processed without pressure loss.

The humidification of the monolithic carrier according to the present invention can be applied without limitation as long as it is a method capable of retaining moisture on the surface of the monolithic carrier. Preferably, the monolithic carrier on which the active catalyst metal is supported is exposed to water vapor, humid air, etc. for a predetermined period of time. It can contain moisture inside and on the surface.

The moisture content contained in the monolith carrier may be 0.001 wt% or more based on the total weight of the water-containing monolith carrier, the relative humidity at the operating temperature of the plasma catalytic reactor is less than 100%, the moisture content before water droplets are formed on the monolith carrier can If the moisture content contained in the monolith carrier is less than 0.001 wt% based on the total weight of the water-containing monolith carrier, the surface conductivity of the monolith channel is low and plasma is weak. There is a problem that sparks or arcs are generated due to too high surface conductivity.

In addition, the catalytically active metal supported on the monolithic carrier is a metal activated by the energy of the discharge, and can be applied without limitation depending on the type of harmful gas to be removed. For example, gold (Au), silver (Ag), platinum ( Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), rhenium (Re), osmium (Os), lanthanum (La), etc. may be at least one type. For example, when the harmful gas is carbon monoxide or a volatile organic compound, it may be platinum that can promote an oxidation reaction, and in the case of nitrogen oxide, it may be ruthenium or rhodium that can promote a reduction reaction.

In addition, the monolithic carrier includes a metal such as manganese (Mn), copper (Cu), nickel (Ni), zinc (Zn), iron (Fe), titanium (Ti) or cobalt (Co) to improve conductivity. It may further be added together with more than one catalytically active metal.

The content of the catalytically active metal and metal supported on the monolithic carrier may be variously set depending on the reactor structure, the driving voltage, the type and density of the harmful gas, etc., but preferably with respect to the total weight of the catalytically active metal and the metal-supported monolithic carrier, The supported amount may be 0.1 wt% to 45 wt%, more preferably 0.1 wt% to 30 wt%. The loading amount in the above range may be effective in treating harmful gases without sparks or arcs.

As such, the catalytically active metal and the metal supported on the monolithic carrier act as a floating ground electrode on the surface of the monolithic carrier, thereby promoting plasma generation by corona discharge.

Meanwhile, in the plasma catalytic reactor according to the present invention, two or more monolithic carriers may be arranged in series. In this case, the types of catalytically active metals supported on the two or more monolithic carriers may be the same or different, so that the treatment efficiency of harmful gases may be improved or different types of harmful gases may be treated simultaneously. The position and size of the two or more monolithic carriers may be set in various ways depending on the structure of the reactor, the driving voltage, the type and density of the harmful gas, and the like.

In addition, in the plasma catalytic reactor according to the present invention, when the content of the catalytically active metal supported on the monolithic carrier is high, or when a catalytically active metal with high conductivity is applied, specifically, when the electric potential of the monolithic carrier is 15 MΩ or less, the monolithic carrier Since normal corona discharge plasma generation is impossible due to spark generation by performing the role of a conductor, in this case, a monolith guard unit 160 is provided between the high voltage electrode 120 and the monolith carrier 110 to prevent spark or arc generation. Thus, plasma generation can be stably performed.

The monolith guard unit 160 is a monolith having an electrical resistance of 16 MΩ or more, and the electrical resistance of the monolith is 16 MΩ or more. and the shape may be a monolith having the same honeycomb shape as the monolith carrier.

At this time, the monolith guard unit 160 may be arranged such that a channel through which harmful gas passes is connected to the channel of the monolith carrier to prevent pressure loss, and the monolith carrier and the monolith guard unit are in contact (ds = 0). , if there is a gap between the monolith guard part and the monolith carrier, the breakdown voltage may increase and thus the discharge power may be reduced.

In addition, the position and size of the monolith guard part may be set in various ways depending on the reactor structure, driving voltage, the type and density of harmful gas, and the like.

The high voltage electrode 120 and the ground electrode 130 are respectively disposed at a predetermined distance (dh and dg) from the monolith carrier 110 in front and rear of the monolith carrier 110 . A high-voltage electrode, a monolithic carrier, and a ground electrode are sequentially positioned along the direction of the harmful gas.

In this case, the gap dh between the high voltage electrode 120 and the monolithic carrier 110 (the gap between the guard part 160 and the high voltage electrode 120 when the guard part is present) is 1 mm to 10 mm, preferably 2 mm ~ 6 mm. If the gap (dh) with the high voltage electrode is less than 1 mm, there is a problem that harmful gases are not uniformly introduced into all monolith carrier channels. This may cause a problem in that plasma cannot be generated .

In addition, the distance dg between the ground electrode 130 and the monolithic carrier 110 may be 2 mm or less, preferably 1 mm or less. If the distance between the ground electrode and the monolithic carrier exceeds 2 mm, the high voltage electrode and the ground electrode move away from each other, resulting in an increase in breakdown voltage and thus a decrease in discharge power.

The high voltage electrode 120 and the ground electrode 130 have a predetermined thickness because harmful gas must pass therein, and one or more openings 121 and 131 may be formed. In this case, the high voltage front and ground electrode may be in the form of a perforated plate having one or more openings through which harmful gases can pass smoothly while maintaining an effective electrode area.

The high voltage electrode 120 is connected to the power supply unit 150, and the power supply unit 150 is electrically connected to a control unit (not shown) to control the magnitude and application time of the voltage applied to the high voltage electrode.

The applied voltage of the power supply may be variously changed according to the reactor configuration and driving conditions, and may preferably be 5 kV to 40 kV in terms of energy efficiency.

Since the AC voltage applied to the high voltage electrode from the power supply is a sinusoidal or pulsed high voltage with a frequency range of 50 Hz to 100 kHz, the power consumption for plasma maintenance is small compared to the conventional radio frequency and inductively coupled plasma method, and the reactor configuration This is simple, and the discharge stability is high, so that a uniform plasma can be generated.

In addition, the power supply may apply a positive (+) polarity DC voltage to the high voltage electrode for uniform plasma generation in the monolith.

The high voltage electrode receives a high voltage from the power supply for a predetermined period of time in the initial stage of driving the plasma catalyst reactor, that is, in a low temperature region before the monolith carrier is sufficiently heated. Plasma is then generated at the potential difference between the high voltage electrode and the monolithic carrier in the gap between the high voltage electrode and the monolithic carrier. That is, plasma is generated in the portion where the harmful gas is injected based on the monolith carrier.

The plasma catalytic reactor according to the present invention decomposes harmful gases into harmless gases by using a plasma reaction in a low temperature region at the initial stage of startup. Of course, the catalytic reaction occurs even in the low-temperature region at the beginning of the start-up, but since the decomposition efficiency is not sufficient, it assists the plasma catalyst function to decompose harmful gases with high efficiency.

In addition, since the plasma catalytic reactor maintains a low electric field inside the monolith carrier when a high voltage is applied to the high voltage electrode, dielectric heating and resistance heating of the carrier occur simultaneously by this electric field.

Therefore, the plasma catalytic reactor according to the present invention can heat the catalytically active metal supported on the monolithic support by using dielectric heating and resistance heating, so that the time at which the catalytically active metal is activated can be advanced. As a result, it is possible to effectively remove harmful gases by increasing catalyst efficiency. In addition, since a separate temperature raising device is not required, the reactor configuration can be simplified, and plasma can be generated at a low voltage in the entire region of the monolith carrier, thereby improving reactor operation efficiency and stability at the same time.

In another aspect, the present invention relates to a harmful gas treatment method characterized in that the harmful gas is treated using the plasma catalytic reactor for removing the harmful gas described above.

The harmful gas treatment method according to the present invention comprises the steps of (a) preparing a reaction by introducing a harmful gas into the plasma catalytic reactor; and (b) when the harmful gas flows into the plasma catalytic reactor, a high voltage is applied to the high voltage electrode and the ground electrode to generate plasma inside the monolithic carrier between the two electrodes, and the harmful gas is treated using a plasma reaction and a catalytic reaction including;

The noxious gas introduced into the plasma catalyst reactor in step (a) may be injected at a flow rate of 10 L/min to 200 L/min based on the monolithic carrier having a width of 9 cm and a height of 5 cm. If the flow rate of harmful gas is less than 10 L/min, ions and electrons generated from the high voltage electrode cannot move quickly to the ground electrode, so a problem may occur that the discharge power is lowered, and if it exceeds 200 L/min Because the residence time of the gas is short, there may be a problem that the harmful gas cannot react properly.

In addition, the harmful gas injected into the plasma catalyst reactor in step (a) may be introduced into the reactor by containing water vapor to supplement the monolith carrier moisture and promote plasma generation. In this case, the relative humidity of the harmful gas may be less than 100% at the plasma catalytic reactor operating temperature. Noxious gas containing moisture in the above range may humidify the inside and the surface of the channel of the monolith carrier to maintain surface conductivity.

The plasma catalytic reactor according to the present invention can perform corona discharge with a discharge power of 5 W or more, preferably 30 W to 100 W inside the monolith carrier even under a low applied voltage condition, so that it is custom-sized for a plasma catalytic reaction. It is possible to apply a commercially available monolithic carrier without the use of a monolithic carrier, and it is possible to effectively treat a large amount of harmful gas by using a plasma reaction and a catalyst without a pressure drop of the catalyst, and at the same time, the maximum voltage applied to the driving electrode By reducing the size, the efficiency and stability of the reactor operation can be improved at the same time.

In addition, the plasma catalytic reactor according to the present invention can receive the reaction energy required for the treatment of harmful gases using a catalyst from low-temperature plasma, so that the treatment of harmful gases is possible without the need for additional heating or energy supply for the catalytic reaction. there is.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are only examples to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

<Example 1>

A plasma catalytic reactor as shown in FIG. 1 was manufactured, and the performance of the plasma catalytic reactor was measured through the experimental setup of FIG. 3 . The monolithic carrier applied to the plasma catalytic reactor is a commercial cordierite monolith having a width (diameter) of 93 mm, a height of 50 mm, and 300 cells per square inch (cpsi), by Ceracomb Co., Ltd., Korea. Cobalt (CO) 0.1 wt%, palladium (Pd) 0.03 wt%, platinum (Pt) 0.07 wt%, and lanthanum (La) 0.03 wt% were supported on the monolith carrier by an impregnation method with respect to the total weight of the monolith carrier Thus, a monolithic carrier on which a catalytically active metal was supported was prepared. Meanwhile, the monolithic carrier on which the catalytically active metal was supported was exposed to air containing 2.2% H ₂ O for 30 minutes to humidify to obtain a monolithic carrier having a moisture content of 0.082 wt%. On the other hand, the high voltage electrode and the ground electrode used a stainless steel perforated plate with 168 holes with a diameter of 3 mm was used, the high voltage electrode and the monolith carrier were arranged at a distance of 2 mm, and the ground electrode was placed in contact with the monolith carrier. Air (containing 2.1% H ₂ O in absolute humidity) was supplied into the reactor at a flow rate of 75 L/min, and a voltage of 2.5 kV was applied to the high voltage electrode to fabricate and drive a plasma catalyst reactor.

<Examples 2 to 12>

A plasma catalytic reactor was manufactured in the same manner as in Example 1, but the plasma catalytic reactor was manufactured and driven under the conditions shown in Table 1 below.

<Comparative Examples 1 to 12>

A plasma catalytic reactor was manufactured in the same manner as in Example 1, but a plasma catalytic reactor was manufactured and driven under the conditions shown in Table 1 below. At this time, the dry monolith carrier of Comparative Example 8 was first dried in an oven at 110 ° C., and then immediately placed in the reactor. In Comparative Example 11, a high voltage was applied except for the monolith carrier in the plasma catalyst reactor of Example 1.

<Example 13>

A plasma catalyst reactor was manufactured in the same manner as in Example 1, but a commercial cordierite monolith having a monolith carrier size of 21 mm in width (diameter) and 31 mm in height was applied, and air (absolute humidity 3.04%) was introduced into the reactor. H ₂ O) was supplied at a flow rate of 30000 hr ^-1 (GHSV) to fabricate and drive a plasma catalyst reactor. At this time, the guard part was mounted without a space (ds = 0) spaced apart between the high voltage electrode and the monolith carrier, and the size of the guard part was 21 mm in width (diameter) and 10 mm in height. Active catalyst metal was not supported. A non-commercial cordierite monolith was used.

<Comparative Example 13>

A plasma catalytic reactor was manufactured and operated in the same plasma catalytic reactor as in Example 12, except that the high voltage electrode and the monolithic carrier were disposed at a distance of 2 mm without a guard, and the ground electrode was positioned so as to be in contact with the monolithic carrier.

<Experimental Example 1: Measurement of discharge power according to time change>

The supply gas was supplied to the reactor by a gas pump whose flow was controlled by a ball flowmeter (RMA-25-SSV, Dwyer, USA), and the amount and temperature of water vapor in the supply gas were measured with a hygrometer (TES-1370 NDIR CO2 Meter, TES Electrical Electronic) Corp.), AC corona plasma was driven by AC high voltage, and was boosted to 400 Hz AC voltage of a frequency converter (Samdong Power Co., Ltd.) by a high-frequency transformer (Taehwa Electric, Seoul). Electrical characteristics were measured with a digital oscilloscope (Tektronix, DPO 3034, four channels, 300 MHz, 2.5 GS/s, USA), a 1000:1 high voltage probe (Tektronix, P6015A, USA), and a current monitor (Pearson Electronics, 2100, USA). measured. The discharge power measured inside the monolith carrier is calculated by the integration of the instantaneous voltage and current expressed by the following Equation 1, and the discharge power according to the time change measured in Examples 1 to 7 and Comparative Examples 1 to 9 is shown in FIGS. 7 to 9 As shown in, discharge images of the plasma catalyst reactor of Example 1 and the plasma catalyst reactor of Comparative Example 11 were captured with a digital camera (Canon EOS 7D, focal length 50mm, ISO-200, Exposure time: 30sec, F-stop: f/3.2 ) was taken and shown in FIG. 6 .

As shown in FIG. 6( a ), in the case of the plasma catalytic reactor of Example 1, it can be confirmed that plasma is generated throughout the reactor, while in the case of the plasma catalytic reactor of Comparative Example 11 as shown in FIG. 6( b ), plasma It has been shown that the generation is generated only on the high voltage electrode side.

In addition, as shown in FIGS. 7 to 9 , in the case of the plasma catalytic reactors of Examples 1 to 7, the discharge power was significantly higher under the same conditions than those of Comparative Examples 1 to 9, and in particular, in the case of Comparative Example 10, the plasma did not occur. In the case of Examples 1 to 7, water molecules and catalytically active metal on the surface of the monolith carrier channel act as a floating ground to increase the discharge power compared to Comparative Examples 1 to 10. Based on this result, it is also smoothly inside the monolith carrier It was confirmed that plasma was generated by corona discharge.

<Experimental Example 2: Measurement of Toluene Removal Performance>

15 ppm of toluene was supplied to the plasma catalyst reactor of Example 8 and Comparative Example 12 at 60 L/min, and the concentration of toluene discharged from the plasma catalyst reactor was measured for each hour, and the results are shown in FIG. 10 . At this time, the toloene removal amount was measured by generating plasma after toluene was saturated because the exact removal amount could not be analyzed before the toluene was saturated, and the energy density was calculated by dividing the power by the flow rate.

As shown in FIG. 8(a), Comparative Example 12 was saturated with toluene faster than Example 8, and as shown in the figure inserted in FIG. 8(a), the adsorption capacity of Comparative Example 12 Silver was 1.3 μmol/g, whereas the adsorption capacity of Example 8 was 6.6 μmol/g, indicating that the adsorption capacity of Example 8 was 5 times greater than that of Comparative Example 12.

In addition, as shown in FIG. 8(b), the maximum transmitted power and energy density of Example 8 were 58 W and 58 J/L, respectively, whereas the maximum transmitted power and energy density of Comparative Example 12 were 35 W and 35 W, respectively. It was found to be J/L.

<Experimental Example 3: Measurement of discharge power according to DC high voltage>

In order to measure the discharge according to the DC high voltage, as in Examples 9 to 12, a positive (+) polarity direct current (DC) high voltage was applied to the high voltage electrode to measure the discharge power.

As a result, as shown in FIG. 11 , as the applied voltage increased, the discharging power increased, confirming that a uniform plasma was formed in the monolithic carrier.

<Experimental Example 4: Measurement of Discharge Power by Guard Mounting>

In order to check whether or not plasma discharge occurs according to the installation of the guard, voltages of 10 kV, 12 kV, 13 kV, 14 kV, 15 kV and 16 kV are applied to the plasma catalyst reactor of Example 13 and Comparative Example 13 to the high voltage electrode to discharge Power was measured, and the results are shown in FIG. 12 .

As shown in FIG. 12, in the case of the reactor equipped with a guard unit as in Comparative Example 13, sparks were generated and the discharge power could not be measured, whereas in the case of the reactor equipped with a guard unit as in Example 13, it was stably in the monolithic carrier. It was confirmed that the plasma was uniformly formed, and it was confirmed that the discharge power increased according to the applied voltage.

Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and it is possible to carry out various modifications within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and this is also the present invention. It is natural to fall within the scope of

Claims (11)

1. A perforated plate-shaped high-voltage electrode;

   a perforated plate-shaped ground electrode positioned to face and spaced apart from the high voltage electrode;

   a monolithic carrier on which a catalytically active metal is supported, which is located between the high voltage electrode and the ground electrode and contains moisture; and

   Including; a power supply for applying an alternating voltage to the high voltage electrode;

   A plasma catalyst reactor for removing harmful gases, characterized in that a voltage is applied to the high voltage electrode by the power supply unit to generate plasma inside the monolith carrier by corona discharge, and the harmful gas is introduced into the plasma region and discharged.
2. A perforated plate-shaped high-voltage electrode;

   a perforated plate-shaped ground electrode positioned to face and spaced apart from the high voltage electrode;

   a monolithic carrier positioned between the high voltage electrode and the ground electrode and on which a catalytically active metal is supported;

   a monolith guard unit disposed between the high voltage electrode and the monolith carrier to prevent arc generation; and

   Including; a power supply for applying a voltage to the high voltage electrode;

   A plasma catalyst reactor for removing harmful gases, characterized in that a voltage is applied to the high voltage electrode by the power supply unit to generate plasma inside the monolith carrier by corona discharge, and the harmful gas is introduced into the plasma region and discharged.
3. A perforated plate-shaped high-voltage electrode;

   a perforated plate-shaped ground electrode positioned to face and spaced apart from the high voltage electrode;

   a monolithic carrier positioned between the high voltage electrode and the ground electrode and on which a catalytically active metal is supported; and

   Including; a power supply for applying a positive (+) polarity DC voltage to the high voltage electrode;

   A plasma catalyst reactor for removing harmful gases, characterized in that a voltage is applied to the high voltage electrode by the power supply unit to generate plasma inside the monolith carrier by corona discharge, and the harmful gas is introduced into the plasma region and discharged.
4. 4. The method according to any one of claims 1 to 3,

   The monolithic carrier is a plasma catalyst reactor for removing harmful gases, characterized in that the width is 9 cm or more and / or the height is 5 cm or more.
5. 3. The method of claim 2,

   The monolith guard unit is a plasma catalyst reactor for removing harmful gases, characterized in that the monolith having an electrical resistance of 16 MΩ or more.
6. 4. The method according to any one of claims 1 to 3,

   The ground electrode is spaced apart from the monolith carrier by 2 mm or less, and is located behind the monolith carrier from which the harmful gas is discharged.
7. 4. The method according to any one of claims 1 to 3,

   The high voltage electrode is spaced apart from the monolith carrier by 1 mm to 10 mm, and is positioned in front of the monolith carrier into which the harmful gas is introduced.
8. 4. The method according to any one of claims 1 to 3,

   The monolithic carrier is a plasma catalyst reactor for removing harmful gases, characterized in that the honeycomb shape.
9. 4. The method according to any one of claims 1 to 3,

   The harmful gas is at least one selected from the group consisting of volatile organic compounds, nitrogen compounds, sulfur oxides, fluorine compounds, chlorine compounds, cyanide compounds, carbon monoxide, carbon dioxide and dioxins, and the harmful gas contains moisture Plasma catalytic reactor for removing harmful gas.
10. 4. The method according to any one of claims 1 to 3,

    The plasma catalytic reactor is a plasma catalytic reactor for removing harmful gases, characterized in that two or more monolithic carriers are arranged in series.
11. Noxious gas treatment method using the plasma catalyst reactor for removing harmful gas according to any one of claims 1 to 3, wherein the relative humidity in the noxious gas is less than 100 vol%.

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