KR100492475B1 - Low temperature plasma-catalysts system for VOC and odor treatment and method using thereof - Google Patents

Abstract

The present invention is a gas inlet (2) into which the pollutant gas in the gas phase is introduced, a low temperature plasma reactor (4) for injecting the polluted gas that has passed through the gas inlet (2) into a plasma and a primary in the low temperature plasma reactor. To the exhaust port 4 'through which the treated gas is discharged, to the nozzle 12 and the nozzle 12 for secondary treatment by injecting the cleaning liquid 20 into the primary treated gas discharged through the exhaust port 4'. A pump 8 for sucking the cleaning liquid 20 of the cleaning liquid storage tank 18 to supply the cleaning liquid 20, and a pipe 10 for supplying the cleaning liquid 20 introduced into the pump 8 to the nozzle 12. In addition, the wet catalyst layer 14 sprayed from the nozzle 12 and the second process gas treated by the cleaning liquid 20 pass through the wet catalyst layer 14 and 3 discharged from the wet catalyst layer 14. Provide a path for directing the primary process gas to the dry catalyst layer 16 and from the wet catalyst layer 14 The washing liquid storage tank 18 storing the discharged washing liquid 20, the dry catalyst layer 16 through which the processing gas passed through the washing liquid storage tank 18 flows into the fourth processing, and the fourth treatment passing through the dry catalyst layer It relates to a low-temperature plasma catalyst composite processing apparatus comprising a blower for sucking the gas and discharged to the gas outlet.

According to the present invention, a large amount of plasma is generated using an economical low-temperature plasma reactor to remove various volatile organic compounds, odors, odors and toxic gases, and to clean the contaminants untreated in the low-temperature plasma reactor. By removing the wet catalyst and the dry catalyst to produce a clean air there is an effect that can reduce various environmental pollution.

Description

Low temperature plasma-catalysts system for VOC and odor treatment and method using

The present invention relates to a volatile organic compound (Volatile Organic Compound) and a method for removing odors, and more particularly to the treatment of volatile organic compounds and odors using a plasma obtained by corona discharge, and not treated in the process The present invention relates to the treatment of untreated volatile organic compounds and odors with a catalyst.

In general, as the use of organic solvents increases, various types of volatile organic compounds and odors are generated in various industrial processes such as waste treatment, coating process, water treatment, and various industrial processes.

Conventionally, various kinds of physical, chemical and biological methods have been used as a technique for removing volatile organic compounds and odors contained in air, and representative examples thereof include cooling condensation, catalytic combustion, physical and chemical adsorption, and cleaning. And biofilters using microorganisms. However, among these methods, physical and chemical methods have high removal efficiency of polluted gases, but they require high operating costs such as facility costs, material costs, and chemical costs. In particular, the combustion method generates a dust and various harmful gases (SOx, CO, NOx), in the case of the cleaning method has a disadvantage of generating a secondary pollution, such as generating waste water.

In addition, in the conventional biological method, the inside of the reactor is filled with a filling material equipped with a microbial membrane, and the contaminated gas is passed through the filling material so that the polluting gas is diffused into the microbial film, thereby oxidizing and decomposing polluting gases such as volatile organic compounds or odors by the microorganism. It is a technique that is purified by the mechanism that becomes. Compared to the physical and chemical treatment methods used to treat volatile organic compounds and odors, this method has a low initial cost and no secondary pollutants. Known as a useful technique. However, the biological method is limited to the treatment of volatile organic compounds that are applied to materials that are well soluble in water and are not well soluble in water such as toluene, xylene, etc., and are not effective due to the lack of microbial management technology. There is a situation.

In order to overcome the above problems, volatile organic compounds and odor treatment methods using plasma have been developed.

The plasma is called a fourth state of matter, followed by solids, liquids, and gases, and generates a discharge by flowing a voltage of several thousand to tens of thousands of volts and a few milliamps of electric current across an electrode composed of a cathode and an anode. It is composed of electrons, ions, and radicals, and their chemical reactions decompose and oxidize polluting gases such as volatile organic compounds and odors.

Korea Utility Model Publication No. 2000-12568 is to install a torsion square bar type plasma discharge rod inside the shear cyclone gas outlet pipe of a multi-cyclone electrostatic precipitator to generate a positive streamer corona on the plasma discharge rod with a high voltage pulse. In this reactor, a device for purifying polluted gas by discharge chemical reaction of radical generation-oxidation reaction-neutralization-end product production is described, and Korean Patent Application Laid-Open No. 2001-0047773 discloses a pipe-shaped dielectric and an outer surface of the dielectric. Plated external electrodes, coil spring-shaped internal electrodes disposed in the dielectric, and a method of treating wastewater by generating a plasma in the dielectric by applying a high frequency low voltage power between the external electrode and the internal electrodes are disclosed. -0073053 is a method for treating polluted gas by streamer corona discharge. And it sets forth, the Republic of Korea Patent Laid-Open Patent 2001-0068436 discloses a method for removing volatile organic compounds and odor using a corona plasma using a plate-like ground electrode is described.

Until now, a lot of methods for treating pollutant gases using plasma have been developed, but an almost cylindrical tube type has to be supplied with excessive power as compared with plasma generation, and clogging due to aerosol by-products when filling catalyst, It is known to hinder the continuous operation of the reactor by lowering the electrical properties.

In particular, in the case of low-temperature plasma, since the rear exhaust gas of the plasma reactor contains some harmful by-products including ozone, it is difficult to be discharged as a completely harmless gas.

In order to overcome such a problem, Korean Utility Model Registration No. 0274616 describes a device for removing untreated harmful by-products discharged from the low temperature plasma reactor by installing a metal filter and a catalyst at the rear end of the low temperature plasma reactor.

The present invention has been made to solve the above-mentioned problems, and the contaminated gas is treated using a plasma reactor into which contaminated gases, such as volatile organic compounds and / or odor gases, are introduced, and are not treated in the plasma reactor, and are not treated. The technical problem is to prepare clean air by treating the polluted gas with a wet catalyst and a dry catalyst.

In addition, the present invention provides a plasma catalyst treatment apparatus including the plasma reactor, a wet catalyst and a dry catalyst.

In one aspect, the present invention is a gas inlet through which the pollutant gas in the gas phase is introduced, a low temperature plasma reactor in which the pollutant gas passing through the gas inlet is introduced into the plasma and the first treated gas is discharged from the low temperature plasma reactor. A nozzle for injecting a cleaning liquid into the first treated gas discharged through the exhaust port, and a second treatment, a pump for sucking the cleaning liquid from the cleaning liquid storage tank to supply the cleaning liquid to the nozzle, and a cleaning liquid introduced into the pump. Route to guide the third process gas discharged from the wet catalyst layer and the wet catalyst layer to be subjected to the third process by passing through the piping to be supplied to the nozzle, the cleaning liquid sprayed from the nozzle and the second processing gas treated by the cleaning liquid. A washing liquid storage tank for providing and storing the washing liquid discharged from the wet catalyst layer; Characterized in that the low temperature plasma catalyst complex processing apparatus including a dry catalyst layer flows through the cleaning liquid storage tank and the fourth processing gas and a blower that sucks the fourth processing gas passed through the dry catalyst layer and discharges it to the gas outlet. do.

In another aspect, the present invention is a contaminated gas is introduced into the plasma reactor, the contaminated gas introduced into the plasma reactor is first processed by decomposing through the plasma reaction, and the cleaning solution to the first processing gas discharged from the plasma reactor Spraying to remove the water-soluble contaminants remaining in the primary treatment gas and to carry out the second treatment. The secondary treatment gas from which the water-soluble contaminants have been removed is subjected to a third treatment by passing through a wet catalyst layer, and then passed through the wet catalyst layer. Characterized in that the pollutant gas treatment method comprising the fourth treatment by passing the primary treatment gas through the dry catalyst layer.

In the low temperature plasma generated in the plasma reactor according to the present invention, when a high-pressure electric discharge is performed among odorous gases generated in a manure treatment plant or the like, electrons generated by the discharge collide with molecules of the odorous gas to change the outer electron state of the gas molecules. Whereby highly reactive radicals (eg, powered by two or more atomic groups, for example, OH, COOH, CHO, etc.), excitation molecules and / or ions, etc., are positively or negatively charged and placed in an electrically neutral state. Gas.

In general, a pulse streamer in which a plasma is formed when a pulse high voltage having a rise time of several tens ns and a duration of about 1 ms or less is applied to a discharge that forms a low temperature plasma. A metal mesh electrode is installed on both sides of the filling of a ceramic ferret having a particle diameter of several nm when an insulating material is sandwiched between parallel electrodes having a few nm of discharge and voids, and an AC high voltage is applied. There is a partial discharge that generates an alternating current high voltage, and lastly, an unbalanced current that generates a corona discharge in the vicinity of light purple.

Therefore, the low temperature plasma according to the present invention uses the corona discharge, and the discharge is started by a high electric field that is concentrated around the electrode having a small radius of curvature even at a low applied voltage.

Meanwhile, a plurality of low temperature plasma reactors for removing contaminant gases such as volatile organic compounds and odors according to the present invention may be installed and used according to a purpose. The low temperature plasma reactor may be used as a low temperature plasma reactor. For example, as long as the electrode is composed of a multi-layered plate or a cylindrical tubular structure, any one may be used. Preferably, a low-temperature plasma reactor using an electrode composed of a multi-layered plate is preferable.

When the pollutant gas flowing into the low temperature plasma reactor contains aromatic hydrocarbons among volatile organic compounds, a wet catalyst layer and a dry catalyst layer are formed at the rear end of the low temperature plasma reactor to filter by-products of aerosol type which are inevitably generated while passing through the plasma reactor. It is provided. In addition, the upper end of the wet catalyst layer is provided with a nozzle for spraying the cleaning liquid to remove the water-soluble material contained in the primary treated gas discharged from the low-temperature plasma reactor water-soluble contamination contained in the primary treated gas Remove the gas.

The catalysts used in the wet catalyst layer and the dry catalyst layer are used in the form of granules, and the usable materials include metal oxides such as MnO ₂ , CoO ₃ , a-Fe ₂ O ₃ , SnO ₃ , ZnO, CuO, TiO _2, and the like. As iron compounds, α-Fe ₂ O ₃ , α-FeOOH, β-FeOOH, and the like, and an oxidation catalyst such as Pd, Ru, Ni, Pt, Au, Ag, and the like, are impregnated with activated carbon, zeolite, or similar composite oxide carrier. Can be used.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of a low-temperature plasma catalyst complex processing apparatus for treating contaminated gas, such as volatile organic compounds and odor according to the present invention.

1 is a process chart for treating the polluted gas according to the present invention, Figure 2 is described as a configuration diagram of a low-temperature plasma catalyst complex processing apparatus according to the present invention.

As shown in Figure 1 and 2, the low temperature plasma catalyst composite processing apparatus according to the present invention is a gas inlet (2) through which the pollutant gas in the gas phase, the pollutant gas passing through the gas inlet (2) is introduced into the plasma To the low temperature plasma reactor 4 for primary treatment, an exhaust port 4 'through which the primary gas is discharged from the low temperature plasma reactor 4, and a primary gas discharged through the exhaust port 4'. A nozzle 12 for spraying the cleaning liquid 20 and performing secondary treatment, a pump 8 for sucking the cleaning liquid 20 of the cleaning liquid storage tank 18 to supply the cleaning liquid 20 to the nozzle 12, and the cleaning liquid. A wet catalyst layer 14 which passes through the gas secondaryly treated by 20 and tertiaryly processes the dry catalyst layer 16 which passes through the wet catalyst layer 14 and undergoes tertiary treatment of gas, and undergoes a fourth treatment; Intake of the fourth treatment gas passed through the dry catalyst layer 16 to the gas outlet (2) It consists of the blower 24 discharged | emitted by 6).

The low temperature plasma reactor 2 consists of rod-shaped electrodes, each of which is surrounded by a chemically or thermally stable protective framework and encounters a high magnetic field. On the other hand, the electrode is connected to the power supply 6 for supplying an alternating voltage of 5kV to 20kV at a specific frequency of several tens to tens of thousands of Hz, and the power supply 6 is connected to the reactor for impedance matching. An inductor and a charging circuit are provided between the power supply device and the low temperature plasma reactor 4.

On the other hand, the pollutant gas is a volatile organic compound and / or odorous substance, each of which is mixed into the gas inlet (2) and divided into two directions through a series of pipes and connected to the ends of the two directions, respectively. It is incorporated into. Here, the low temperature plasma reactor (4) may be installed at least one or more according to the capacity and efficiency, if necessary, by installing an air filter between the gas inlet (2) and the low temperature plasma reactor (4) the low temperature plasma reactor (4) Optimum plasma generation can be induced by filtering the contaminated gas mixed inside.

The nozzle 12 spraying the cleaning liquid 20 to remove the water-soluble contaminants present in the primary treated gas through the low temperature plasma reactor 4 is the low temperature plasma reactor 4 and the wet catalyst layer 14. The suction liquid 20 is provided between the suction liquid 20 stored in the bottom surface of the cleaning liquid storage tank 18 to be described later with the pump 8 and the nozzle (10) through the pipe 10 connected to one side of the pump (8) 12). At this time, the cleaning liquid 20 flowing into the nozzle 12 uses a cleaning liquid 20 used in a conventional environmental treatment system.

On the other hand, the lower end of the nozzle 12 is provided with a wet catalyst layer 14, the cleaning liquid storage tank 18 is provided at the lower end of the wet catalyst layer 14, the cleaning liquid storage tank 18 and the wet catalyst layer. A wall having a plurality of first holes 22 is provided at the interface of 14 to prevent the catalyst particles of the wet catalyst layer 14 from flowing into the cleaning liquid storage tank 18 and sprayed from the nozzle 12. Passing through the cleaning liquid 20 and the wet catalyst layer 14 provides a flow path of the treated third process gas. Therefore, the diameter of the first hole 22 should be smaller than the diameter of the catalyst particles of the wet catalyst layer 14 and its size can be determined in consideration of the pressure drop according to the operation time.

The cleaning solution storage tank 18 installed at the lower end of the above-described wet catalyst layer 14 forms a boundary with the wet catalyst layer 14 and the dry catalyst layer 16, and the cleaning solution 20 is stored to a predetermined height from the bottom surface thereof. In order to circulate the cleaning liquid 20 to the nozzle 12, a pipe connected to the pump 8 is provided on the bottom surface of the cleaning liquid storage tank 18. In addition, one side of the bottom face is provided with a cleaning liquid discharge port 28 so that the cleaning liquid 20 can be discharged to the outside.

On the other hand, the dry catalyst layer 16 is provided on the upper side of the cleaning liquid storage tank 18 so as to be adjacent to the wet catalyst layer 14, the wall is provided with a plurality of second holes (22 ') at the interface is the wet catalyst layer 14, the third treatment gas sequentially passed through the washing liquid storage tank 18 is mixed, and the fourth treatment gas passing through the dry catalyst layer 16 is sucked into the upper portion of the dry catalyst layer 16. The blower 24 and the gas outlet 26 for discharging to the outside is provided.

Referring to the operation of the low-temperature plasma catalyst complex processing apparatus according to the present invention having the above-described configuration in detail as follows.

The contaminated gas is introduced into the gas inlet 2, and the contaminated gas introduced into the gas inlet 2 is decomposed and firstly processed while passing through the low temperature plasma reactor 4, and the low temperature is discharged to discharge the last harmless gas. The secondary treatment gas was sprayed on the primary treatment gas treated by the plasma reactor 4 by using the nozzle 12, and the second treatment gas treated by the cleaning liquid was subjected to the wet catalyst layer 14. Tertiary treatment by passing through and oxidizing, and tertiary treatment by passing the tertiary treatment gas treated by the wet catalyst layer 14 to the dry catalyst layer 16, passing the fourth treatment gas to the blower 24 It is discharged to the gas outlet 26 by using.

As described above, when the pollutant gas containing the volatile organic compound and / or odor is introduced into the gas inlet 2 of the low temperature plasma catalyst complex processing apparatus according to the present invention and mixed into the low temperature plasma reactor 4, the power source By supplying power to the supply device to induce a corona discharge to the plasma reactor, the mixed polluted gas is first treated, and then discharged through an exhaust port 4 'installed at one side of the low temperature plasma reactor 4.

The primary processing gas discharged to the exhaust port 4 ′ of the low temperature plasma reactor 4 flows through the nozzle 12 to the bottom, whereby the cleaning liquid 12 is sprayed from the nozzle 12 to the primary. Removes water-soluble contaminants and dust remaining in the process gas.

Subsequently, the secondary processing gas from which the water-soluble contaminants and dusts are removed by the cleaning liquid 20 moves to the wet catalyst layer 14 provided at the lower end of the nozzle 12 and remains in the secondary processing gas. The reacted contaminants are oxidized to produce a tertiary treatment gas.

Meanwhile, the tertiary treatment gas moves along with the cleaning liquid 20 through a plurality of first holes 22 provided at the lower end of the wet catalyst layer 14, and the cleaning liquid passing through the first hole 22 ( 20 is collected at the bottom of the washing liquid storage tank 18 and is sucked by the pump 8 to be transferred to the nozzle 12 through the pipe 10, the third process gas passes through the upper end of the washing liquid storage tank 18. After that, it passes through the plurality of second holes 22 'and flows into the dry catalyst layer 16.

The tertiary treatment gas introduced into the dry catalyst layer 16 reduces contaminants remaining in the tertiary treatment gas to be treated as a final harmless gas, which is referred to as a fourth treatment gas in the present invention.

The fourth process gas, which is the above-mentioned harmless gas, is discharged to the gas outlet 26 due to the blower 24 provided at the upper end of the dry catalyst layer 16.

  Hereinafter, the present invention will be described in detail through examples. However, the following examples are only for illustrating the present invention in detail and are not intended to limit the scope of the present invention by these examples.

<Example>

As shown in FIG. 2, the low-temperature plasma reactor 2 [140W × 700L × 310H, Up-to-date, Swiss], a wet catalyst layer 14 having a volume of 1.07 m 3, and a dry catalyst layer having a volume of 1.07 m 3 ( After the low temperature plasma catalyst composite processing apparatus including the 16) and the blower 24 and the like was formed, the wet catalyst layer 14 and the dry catalyst layer 16 were filled with the catalyst, and the cleaning liquid storage tank 18 was filled with the appropriate amount of the cleaning liquid.

Then, 200 ppm hydrogen sulfide is injected into the pollutant gas inlet 2 at a rate of 250 m ³ / min as the pollutant gas, and the power supply device 6 of the low temperature plasma reactor 2 is supplied with a fixed voltage of 11 kV. The current was adjusted from 150 mA to 380 mA, causing a corona discharge inside the low temperature plasma reactor 2.

Then, the cleaning liquid stored in the cleaning liquid storage tank 18 is circulated to the nozzle 12 using the pump 8, and the concentration of the initial hydrogen sulfide and the concentration of the processing gas discharged to the gas outlet are measured using a mass spectrometer. HIDEN Dynamic Mass].

As a result, it was found that 99.8% of the initial hydrogen sulfide concentration of 200 ppm was removed at a current of 280 mA.

Comparative Example

After injecting 200 ppm of hydrogen sulfide at a rate of 250 m ³ / min into the low temperature plasma reactor [140W × 700L × 310H, Up-to-date, Swiss] shown in FIG. 2, the power supply device 6 of the plasma reactor 2 was supplied. The power was applied to fix the voltage of the plasma at 11 kV, adjust the current from 150 mA to 380 mA, and cause a corona discharge inside the low temperature plasma reactor 2.

Then, the initial hydrogen sulfide concentration and the concentration of the processing gas discharged from the low temperature plasma reactor were measured by a mass spectrometer [Mass spectra, HIDEN Dynamic Mass].

As a result, 70% of the initial hydrogen sulfide concentration was treated at a current of 280 mA.

As described above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the exemplary embodiments described above are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention should be construed that all changes or modifications derived from the meaning and scope of the appended claims and their equivalents, rather than the detailed description, are included in the scope of the present invention.

The present invention generates a large amount of plasma using an economical low-cost plasma reactor to remove various volatile organic compounds, odors, odors, toxic and harmful gases, and to clean the contaminants untreated in the low-temperature plasma reactor, liquid, wet By removing the catalyst and dry catalyst to produce a clean air there is an effect that can significantly reduce various environmental pollution.

In addition, the present invention removes untreated contaminants from the low-temperature plasma reactor using the cleaning liquid, the wet catalyst, and the dry catalyst as one device, and thus does not require the modification of the device according to the water-soluble or poorly soluble contaminated gas, and the wet catalyst. And by using a dry catalyst to oxidize and reduce at the same time there is an effect that can be treated to toxic decomposable toxic gases.

1 is a process chart for treating the polluting gas according to the present invention,

2 is a block diagram of a low-temperature plasma catalyst composite processing apparatus according to the present invention,

<Description of the symbols for the main parts of the drawings>

2: gas inlet 4: low temperature plasma reactor

4 ': exhaust port 6: power supply

8: pump 10: piping

12 nozzle 14 wet catalyst layer

16: dry catalyst layer 18: washing liquid storage tank

20: cleaning liquid 22: first hole

22 ': 2nd hole 24: blower

26 gas outlet 28 cleaning liquid outlet

Claims (4)

A gas inlet (2) into which the pollutant gas in the gas phase flows in, a low temperature plasma reactor (4) in which the pollutant gas passing through the gas inlet (2) flows into the plasma and the first treated gas in the low temperature plasma reactor Is discharged through the exhaust port 4 ', the cleaning liquid 20 is sprayed on the primary treated gas discharged through the exhaust port 4', the nozzle 12 for secondary treatment, and the cleaning liquid 20 to the nozzle 12. Pump (8) for sucking the cleaning liquid (20) of the cleaning liquid storage tank (18), the pipe (10) for supplying the cleaning liquid (20) introduced into the pump (8) to the nozzle (12), and the nozzle. (3) the wet catalyst layer 14 to be passed through the cleaning liquid 20 and the secondary treatment gas treated by the cleaning liquid 20 and tertiary treatment, and the third treatment gas discharged from the wet catalyst layer 14 Provides a path leading to the dry catalyst layer 16 and discharged from the wet catalyst layer 14 The washing liquid storage tank 18 for storing the semen 20, the dry catalyst layer 16 through which the third processing gas passed through the washing liquid storage tank 18 flows, and the fourth processing gas passing through the dry catalyst layer A low temperature plasma catalyst complex processing apparatus comprising a blower that sucks and discharges the gas to a gas outlet. The method of claim 1, The catalyst filled in the wet catalyst layer and the dry catalyst layer is any one of MnO ₂ , CoO ₃ , a-Fe ₂ O ₃ , SnO ₃ , ZnO, CuO, TiO ₂ , α-Fe ₂ O ₃ , α-FeOOH or β-FeOOH A low temperature plasma catalyst complex processing apparatus, wherein one is selected, or any one of Pd, Ru, Ni, Pt, Au, or Ag is impregnated with activated carbon or zeolite. The contaminated gas is introduced into the plasma reactor, the contaminated gas introduced into the plasma reactor is firstly decomposed through the plasma reaction, and the cleaning solution is injected into the primary processing gas discharged from the plasma reactor to the primary processing gas. The remaining water-soluble contaminants are removed and subjected to secondary treatment, and the secondary treatment gas from which the water-soluble contaminants have been removed is subjected to the third treatment by passing through the wet catalyst layer, and the third treatment gas passing through the wet catalyst layer is passed through the dry catalyst layer. Pollution gas treatment method comprising the fourth treatment. The method of claim 3, wherein The catalyst filled in the wet catalyst layer and the dry catalyst layer is any one of MnO ₂ , CoO ₃ , a-Fe ₂ O ₃ , SnO ₃ , ZnO, CuO, TiO ₂ , α-Fe ₂ O ₃ , α-FeOOH or β-FeOOH A method for treating polluted gas, characterized in that one selected or any one of Pd, Ru, Ni, Pt, Au, or Ag is impregnated with activated carbon or zeolite.