KR20030065068A - Mixture and one-body type purification apparatus with dielectric barrier structure - Google Patents

Abstract

PURPOSE: Provided is a hazardous gas purification apparatus having dielectric barrier structure for increasing hazardous gas treatment efficiency by increasing plasma discharge efficiency and photochemical reaction activities. CONSTITUTION: The apparatus includes a power supply(100), a dielectric structure carrier installed in a reactor and comprised of a plurality of honeycomb carrier cells(132), discharging electrodes(110) and corresponding electrodes(120) alternatively arranged installed in the honeycomb carrier cells(132), respectively, for causing discharge in the cells(132), wherein the cells(132) are coated with catalyst or photocatalyst.

Description

Mixture and one-body type purification apparatus with dielectric barrier structure

The present invention relates to a noxious gas purifying apparatus for purifying the noxious gas discharged from an indoor air purifying apparatus, an internal combustion engine or an incinerator. More specifically, by inducing electrodes in a honeycomb carrier cell coated with a catalyst / photocatalyst to induce dielectric barrier discharge, the dielectric can increase the plasma discharge efficiency and the photochemical reaction activity to improve the harmful gas treatment efficiency. The present invention relates to a mixed unit type harmful gas purifying apparatus having a barrier structure.

In general, as a method for purifying harmful exhaust gas from an engine or an incinerator, a method of generating corona discharge by high voltage and oxidizing or reducing harmful components by plasma chemical reaction is used. Exhaust gas purification apparatus using corona discharge uses the principle of purifying harmful substances (nitrogen oxides, sulfur oxides, VOCs, dioxins, etc.) contained in the exhaust gas. Various techniques have been proposed to increase the exhaust gas removal efficiency of the corona discharge type exhaust gas purification device. Known corona discharge type exhaust gas purifiers include a linear wire electrode-to-cylinder type with a corona discharge electrode, and a needle electrode-to-flat type with a corona discharge electrode as a needle. -to-plate) and the like.

In addition, a purification method using a photocatalyst is also used, which irradiates a photocatalyst, for example TiO ₂ , with a light source having a specific wavelength to purify contaminants with free radicals generated when the photocatalyst is excited.

The use of the plasma purifier or photocatalytic purifier by the corona discharge described above is not only limited in the purification treatment, but also the efficiency is not high. Therefore, in recent years, in order to improve processing performance, a mixed harmful gas purifying apparatus of a plasma and a catalyst or a photocatalyst in combination thereof has been developed.

Since the life cycle of chemical species (various ions, radicals) generated by plasma is usually several microseconds or less, in order for the chemical species generated within this short time to react with the catalyst, the plasma generating part and the catalytic reaction part are separated separately. If present, it is difficult to obtain high gas purification efficiency.

In addition, in the case of the photocatalyst, it is found that the wavelength of light for activating the photochemical reaction is the UV region (400 nm wavelength region, the light energy is more than 3 eV by E (eV) = hc = hv / λ = 1239 / λ). Purifiers are being developed that are mixed with plasma instead of UV lamps, which are used as conventional UV light generators, xenon lamps, mercury lamps, black lights, cold cathode discharge tubes, and the like. This is because the energy efficiency of existing UV lamps is as low as 20% and is somewhat complicated to use in combination with photocatalysts. Furthermore, in the purification apparatus mixed with the plasma, a synergy effect of the gas purification performance by the plasma and the gas purification performance by the photocatalyst can be obtained. This mixed purifier is described with reference to FIGS. 1 to 4 as follows.

FIG. 1 shows a plasma and catalyst / photocatalyst-integrated noxious gas purification apparatus in which discharge occurs at both ends of a conventional catalyst. This apparatus arranges electrodes 12 and 14 on both sides of the reactor 10 to generate a discharge plasma, and places a catalyst 20 between the electrodes 12 and 14 to introduce harmful gas. Is purifying. However, in this apparatus, the formation of plasma by discharge occurs only around the electrodes 12 and 14 so that the longer the length of the catalyst 20 is, the central part of the catalyst 20 is excluded from the simultaneous reaction with the plasma, so that the purification efficiency is increased. This diminishing problem was caused. In order to solve such a problem, the middle of the longer catalyst 20 may be divided into multiple stages, but in this case, a new problem of increasing capacitance in the discharge device is encountered.

2 is a block diagram of a conventional flat electrode-type discharge electrode-coupled plasma and a catalyst / photocatalyst mixed-integrated noxious gas purifying apparatus. As shown in FIG. 34), the catalyst 40 is attached to the flat plate 32 so that the reaction by the catalyst 40 occurs together with the plasma. However, in this device, as shown by the dotted line, the discharge by the wire electrode 30 is concentrated from there near to the plate 32, which does not induce the activation of the overall reaction of the catalyst 40.

3A and 3B show a plasma and a catalyst / photocatalyst mixed-integrated toxic gas purification apparatus in which a catalyst is coated on a conventional wire-cylindrical discharge electrode. In the apparatus disclosed in FIG. 3A, the catalysts 60 are attached to the inner wall of the cylinder 50, and the plasma discharge electrode 52 is positioned on the central axis thereof to generate plasma. Catalysts 60 located on the inner wall are activated to react with the noxious gas. In addition, the apparatus shown in FIG. 3B also arranges the wire type discharge electrode 52a on the central axis of the cylinder 50a, and the catalyst 60a is perpendicular to the discharge electrode 52a toward the discharge electrode 52a on the inner wall thereof. Place them. In such devices, since the discharge is mainly generated only around the wire-type discharge electrodes 52 and 52a, the plasma is not easily spread to the cylinders 50 and 50a, which is very inefficient for activating the catalysts 60 and 60a.

Figure 4 shows a configuration of a mixed separation type harmful gas purification apparatus in which the generating region of the conventional plasma and the catalyst is separately separated, the apparatus shown here is a wire type only in the inlet portion 72 of the cylinder 70 into which gas is introduced. Plasma discharge is generated only between the discharge electrode 74 and the cylinder 70, which is the counter electrode electrode corresponding thereto, and the catalyst (not shown) in the intermediate portion 76 in which the volume of the cylinder 70 behind is increased. Si) is used as a catalytic reactor. Therefore, this apparatus has a structure in which the gas purifying reaction by plasma and the gas purifying reaction by the catalyst are separated and processed in parallel, so that the synergy effect affecting each other has a blind spot that is difficult to expect.

Accordingly, an object of the present invention is to overcome the above problems, by placing electrodes in a honeycomb carrier cell coated with a catalyst / photocatalyst to induce a dielectric barrier discharge to induce maximum synergy effect plasma discharge The present invention provides a mixed-integrated noxious gas purification apparatus having a dielectric barrier structure that increases efficiency and increases photochemical reaction activity to improve noxious gas treatment efficiency.

Detailed description of the embodiments of the present invention will be made with reference to the accompanying drawings, in which numerals designating corresponding parts in the drawings are the same.

1 is a block diagram of a plasma and catalyst / photocatalyst mixed-integrated toxic gas purification apparatus in which discharge occurs at both ends of a conventional catalyst,

2 is a block diagram of a conventional plate-wire discharge electrode coupled plasma and catalyst / photocatalyst mixed integral toxic gas purification apparatus,

3A and 3B are schematic diagrams of a plasma and catalyst / photocatalyst-integrated toxic gas purification apparatus in which a catalyst is coated on a conventional wire-cylindrical discharge electrode,

4 is a configuration diagram of a mixed separation type harmful gas purifying apparatus in which a generation area of a conventional plasma and a catalyst is separately formed,

Figure 5 is a side cross-sectional view showing the configuration of a hybrid integrated harmful gas purification apparatus having a dielectric barrier structure according to the present invention,

6a and 6b are front views showing the wiring method of the electrode in the present device,

7a and 7b are views showing the coupling structure of the electrode in the present device,

FIG. 8 is a model diagram of active species generation by plasma and a catalyst / photocatalyst in the mixed-integrated noxious gas purification apparatus of the present invention

9A is a cross-sectional photograph of a catalyst carrier cell located between a discharge electrode and a counter electrode in the mixed body type harmful gas purifying apparatus of the present invention.

FIG. 9B is a photograph of a discharge phenomenon occurring in a discharge electrode and a counter electrode between the catalyst carrier cells shown in FIG. 9A in a dark room;

10A and 10B are diagrams showing voltage / current waveforms and required energy for plasma generation at the time of pulse waveform input to the mixed-integrated noxious gas purifying apparatus of the present invention.

** Explanation of symbols for main parts of drawings **

100: power supply 110: discharge electrode

112: first wire 120: counter electrode

122: second wire 130: carrier

132: carrier cell 140: insulating film

150: reactor 152,154: piping

160,162 Electric Injector

Mixed-integrated noxious gas purifying apparatus having a dielectric barrier structure according to the present invention for achieving the above object is in the noxious gas purifying apparatus for purifying the noxious gas introduced into the reactor through a pipe, AC, DC, pulse power A power supply unit generating or supplying each or a combination; A dielectric carrier having a honeycomb carrier cell positioned in the reactor; A discharge electrode positioned within the carrier cells while skipping adjacent ones of the carrier cells and receiving power from the power supply unit; And a counter electrode electrode disposed in the carrier cells alternately with the discharge electrodes and receiving power from the power supply unit to form an electric field with the neighboring discharge electrodes to cause discharge.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 5 is a side cross-sectional view showing the configuration of a hybrid integrated type harmful gas purification apparatus having a dielectric barrier structure according to the present invention. 6A and 6B are front views showing the wiring methods of the electrodes in the apparatus, and FIGS. 7A and 7B are views illustrating the coupling structure of the electrodes in the apparatus.

As shown in FIG. 5, the apparatus includes a power supply unit 100 for supplying power for discharging. In the power supply unit 100, AC, DC, and pulses may be respectively applied in combination or boosted, and it is possible to use all inexpensive AC, DC, and pulse power supplies currently commercially available. In addition, electrodes 110 and 120 having different polarities connected to the power supply unit 100 and a carrier 130 on which the electrodes 110 and 120 are positioned are provided. The carrier 130 is composed of honeycomb-type small carrier cells 132, and each of the carrier cells 132 is coated with a catalyst or a photocatalyst. Electrodes 110 and 120 are positioned inside the carrier cells 132 so that an electric field is formed between the electrodes when electricity is supplied to cause discharge. In particular, an insulating film 140 is interposed between the reactor 150 and the carrier 130. In order to supply electricity to the electrodes 110 and 120, the first and second wires 112 and 122 are connected to the reactor from the power supply unit 100. 150 is entered into the reactor, in which the electric reactors 160 and 162 are installed to insulate the wires 112 and 122 and stably supply power to a portion to be entered into the reactor 150. Of course, the harmful gas is introduced from the side of the carrier 130 through the pipe 152 connected to the reactor 150 and flows inside the carrier 130 as shown in the arrow of FIG. Will be discharged through. As a catalyst, a general catalyst and a photocatalyst are used, and a suitable type is selected according to the intended use. For example, a suitable type of catalyst is selected according to the use of dust particles, deodorization of odor (aromatic) molecules, removal of NOx / SOx, removal of CO, and the like. It is used as gas purifier of diesel engine flue gas, industrial plant flue gas, power plant flue gas, emergency power plant flue gas, and indoor air conditioner.

The wall surface of the carrier cell 132 described above is mainly used alumina (Al ₂ O ₃ ) or zeolite (Zeolite) which is a high dielectric constant insulator, and the discharge phenomenon according to the present invention is a dielectric barrier discharge (DBD) Are classified as). Having such a structure of dielectric barrier discharge maintains stable and continuous discharge even when a low voltage is applied or when the distance between the electrodes 110 and 120 and the catalyst or photocatalyst is very close. This potential difference inputted by the dielectric polarization is also the carrier cell (132) located between the conductor of the discharge electrode 110 and the other discharge electrode 120, the insulator, but in the other hand is a dielectric having a dielectric constant (ε _r) (V _input) By reducing the voltage and increasing the charge inflow, the memory potential (V _memory ) is induced by the dielectric capacitance, so the total potential difference (V _total = V _input + V _memory ) becomes larger than the input potential difference, resulting in discharge efficiency. It will act to increase.

The electrodes 110 and 120 are also manufactured in the same size and number in proportion to the size and number of the carrier cells 132. In addition, the larger and smaller the number of the carrier cell 132 is easier to manufacture, but preferably the larger and larger the number of the carrier cell 132, the gas purification efficiency is increased. Even if the electrodes 110 and 120 are in contact with the carrier cell 132, the transition to the arc does not progress unless it generates an electric field more than necessary. However, as the center of gravity increases in the center, the electrode 110 and 120 are preferably positioned at the center of the carrier cell 132.

In the present apparatus, the lengths of the electrodes 110 and 120 may be adjusted because they are proportional to the length d of the catalyst 130. In addition, since the length and the intensity of the discharge electric field are not correlated, the discharge is not affected by the length. Insertion of the electrodes (110, 120) is made horizontally while maintaining a predetermined interval along the longitudinal direction of the carrier cell 132, the wires (112, 122) connected to the power supply unit 100 and the electrodes (110, 120) located inside the carrier cell (132) 6A can be wired vertically and horizontally as shown in FIG. 6A, that is, two components are wired at right angles, or diagonally as shown in FIG. 6B, wherein the discharge electrode 110 and the counter electrode 120 are connected to each other. Allow power to be supplied from opposite sides of the catalyst 130 to each other. In particular, the electrodes 110 and 120 may not only be connected to the insertion end in parallel as shown in Figure 7a, but also inserted into the carrier cell 132 as shown in Figure 7b and then inside the carrier cell 132 End parts can also be connected and connected. In this case, since the electrodes 110 and 120 are connected inside the carrier 130, holes for connecting lines to the carrier cell 132 to pass through the carrier cells 132 to be connected to the electrodes in the respective carrier cells 132 that the electrodes are adjacent to. At the end of 132.

FIG. 8 is a model diagram of active species generation by plasma and a catalyst / photocatalyst in the mixed body harmful gas purifying apparatus of the present invention.

In this figure, the plasma is formed by the discharge in the carrier cell 132 between the discharge electrode 110 and the counter electrode 120, and as soon as the species is generated by the plasma, it can react with the catalyst or the photocatalyst. From this, it can be seen that the energy consumption for generating species can be reduced when the distance between the plasma discharge unit and the catalyst or photocatalyst is very close. In particular, the photocatalyst is activated by using light in the UV wavelength region emitted by the discharge.

FIG. 9A is a cross-sectional photograph of a catalyst carrier cell located between a discharge electrode and a counter electrode in the mixed body type harmful gas purifying apparatus of the present invention, and FIG. 9B is a cross section of the discharge electrode and the counter electrode with the catalyst carrier cell shown in FIG. 9A interposed therebetween. This is a picture of the discharge phenomenon in the dark room. Here it can be seen that the discharge is generated in the entire part of the electrode. Accordingly, it will be demonstrated that the apparatus can provide sufficient contact time for the reaction of chemical species with plasma and catalyst or photocatalyst.

10A and 10B are diagrams showing voltage / current waveforms and required energy for plasma generation at the time of pulse waveform input to the mixed-integrated noxious gas purifying apparatus of the present invention.

The material of the carrier cell is mostly composed of alumina, which is an insulator. The cell thickness is usually 0.2 ~ 0.5mm, and the electric field strength that alumina of 0.1mm thickness can withstand is 1.2kV, so when an electric field of 3 ~ 5kV is actually applied It can be confirmed that the discharge formation is good. At this time, the maximum dielectric barrier discharge is possible up to the dielectric breakdown potential that can withstand the thickness of the carrier cell.

The energy input amount when the pulse voltage is applied as in FIG. 10A is 0.007J in FIG. 10B, and thus 2.1 W is required when operating at 300 Hz. In this case, the amount of energy required depends on the total length of the electrode applied to the carrier cell of the catalyst. Of course, not only the pulse voltage, but also a very similar amount of energy is input in AC and DC.

Hereinafter, the operation and effect of the apparatus will be described in detail with reference to the attached conductive surfaces.

The power supply unit 100 multiplies DC, AC, and pulses individually or in combination for discharge. At this time, the plasma light energy generated by the discharge depends on the gas participating in the discharge. Of course, even if the participating gas is a harmful gas, the main components are mainly nitrogen, oxygen, and moisture. The generated plasma light energy is mainly 3 to 4 eV, and the kinetic energy for ionizing gas molecules by free electrons (along with the avalanche) generated at this time is 0 to 20 eV. The chemical species of the gas component generated by such energy are immediately present in the carrier cell 132 and immediately reacted with the catalyst 130 or the photocatalyst to be treated. At this time, in the case of the discharge by the pulse power source, there is an advantage that can generate a large amount of free electrons having a large ionization energy.

Furthermore, the noxious gas purifying apparatus according to the present invention is capable of reacting the catalyst or photocatalyst with the chemical species produced by the discharge sequentially, so that the reaction proceeds in a state where molecules of the noxious gas are excited (excited). Therefore, the reaction proceeds more advantageously than the reaction in the molecules in the ground state, resulting in an increase in processing efficiency. In particular, the chemical species generated by the ^{discharge-life} period of the (· O, N ·, OH, O _2, O ₂ ^+, N ⁺ _2, such as various ions and radicals) is usually 10 ^-6 to 10 ^-12 seconds to, The device is composed of a mixture of plasma and catalyst or photocatalytic reaction in close proximity, allowing chemical species to react with the catalyst surface within the life cycle of these short species.

As described above, the mixed-integrated noxious gas purifying apparatus having the dielectric barrier structure according to the present invention is capable of uniformly treating noxious gases because the discharge is uniformly formed in the carrier cell of the catalyst along the electrode, and the mutual reaction is also possible. The synergy effect is doubled. In addition, the chemical reaction between the chemical species produced by the plasma and the catalyst or photocatalyst proceeds almost simultaneously in order to maximize the synergy effect between the reactions. As a result, not only energy consumption can be reduced, but also the effect of improving the treatment efficiency of harmful gases.

The embodiments disclosed herein are only presented by selecting the most preferred examples to help those skilled in the art from the various possible examples, the technical spirit of the present invention is not necessarily limited or limited only by this embodiment, Various changes and modifications are possible within the scope without departing from the spirit of the invention, as well as other equivalent embodiments.

Claims (4)

In the noxious gas purification device for purifying the noxious gas introduced into the reactor through the pipe, A power supply unit generating or supplying alternating current, direct current, and pulse power; A dielectric carrier having a honeycomb carrier cell positioned in the reactor; A discharge electrode positioned within the carrier cells while skipping adjacent ones of the carrier cells and receiving power from the power supply unit; And A mixed body type harmful substance having a dielectric barrier structure including a counter electrode disposed in the carrier cells alternately with the discharge electrodes and receiving power from the power supply unit to form an electric field with the neighboring discharge electrodes to cause discharge. Gas purifier. The method of claim 1, wherein the number and length of the electrodes inserted horizontally into the carrier cell is proportional to the number and length of the carrier cells, respectively, and the thickness of the electrode is the size of the carrier cell so that harmful gas can flow A smaller one is used, wherein the electrodes are arranged in the carrier cells horizontally, but are wired in a right angle or diagonal direction through wires from the power supply unit. 3. The apparatus of claim 2, wherein the carrier cell is coated with a catalyst and / or a photocatalyst. 4. The apparatus of claim 3, wherein an insulating film for insulation is interposed between the reactor and the carrier.