KR101226603B1 - Apparatus for treating hazardous gas using counterflow of plasma and hazardous gas, method for treating hazardous gas using the same - Google Patents

Abstract

Disclosed is a harmful gas treatment apparatus using a counter-flow of plasma and harmful gas that can achieve a constant decomposition efficiency even when a large amount of harmful gas is injected by maximizing the mixing of plasma and harmful gas. To this end, a plasma generating means for generating a plasma by applying a voltage between the negative electrode and the positive electrode, and connected to the rear end of the plasma generating means, injecting harmful gas supplied from the outside in the opposite direction to the plasma flow, It provides a harmful gas treatment apparatus using a counter flow of the plasma and harmful gas including a counter flow chamber for discharging the harmful gas to the outside. According to the present invention, since the harmful gas is injected in the opposite direction to the plasma flow, the plasma and the harmful gas are sufficiently mixed, and the high temperature at which the plasma and the harmful gas are mixed is sufficient than when the harmful gas is injected in the same direction as the plasma flow. Since the residence time of the noxious gas in the zone is increased, the decomposition efficiency is improved.

Description

Noxious gas treatment system and treatment method using counter-flow of plasma and noxious gas {APPARATUS FOR TREATING HAZARDOUS GAS USING COUNTERFLOW OF PLASMA AND HAZARDOUS GAS, METHOD FOR TREATING HAZARDOUS GAS USING THE SAME}

The present invention relates to an apparatus for treating harmful gases using a counter flow of plasma and noxious gas, and more particularly, to improve the decomposition efficiency of noxious gases and to decompose noxious gases by allowing the inflow direction of the plasma and noxious gases to face each other. The present invention relates to a harmful gas treatment apparatus and a treatment method using a counter flow of plasma and noxious gas, which can reduce the amount of energy used in the apparatus.

Perfluoro-Compounds (abbreviated as 'PFCs' gas) account for about one-tenth of the carbon dioxide, but the global warming index is higher than carbon dioxide, and remains undissolved for a long time in the atmosphere, resulting in global warming. It is well known as a major causative agent of.

Therefore, countries around the world signed a climate change agreement at the Rio meeting in Brazil in June 1992 and defined PFCs as global warming gas, and adopted the Kyoto Protocol on November 10, 2001. And the timing of regulation. Therefore, developed countries such as the US, Japan, and Europe are required to reduce the PFCs emission reduction target standard to 10% from 1995 to 2010, and Korea to reduce 10% by 1997 to 2010, and Taiwan compared to 1998. It is required to reduce 10% by 2010.

In particular, in order to etch the surface of the wafer during the semiconductor manufacturing process, acid gases such as BCl ₃ , Cl ₂ , F ₂ , HBr, HCl, HF and CF ₄ , CHF ₃ , C ₂ F ₆ , C ₃ F ₈ , C ₄ PFCs such as F ₆ , C ₄ F ₈ , C ₅ F ₈ , SF _6, etc. are used, and in the deposition step of the Chemical Vapor Deposition (CVD) process, AsH ₃ , NH ₃ , Gases such as PH ₃ , SiH ₄ , Si ₂ H ₂ Cl _2, etc. are used, and PFCs such as NF ₃ , C ₂ F ₆ , C ₃ F _8, etc. are used in the cleaning step, so a process for treating them is essential. do.

Methods for removing the aforementioned PFCs gas include a direct combustion method, an indirect heating method, a catalyst method, a plasma method, etc. The double direct combustion method of 1,400 to 1,600 ℃ generated during the combustion of liquefied natural gas (LNG) or hydrogen The flame is used to oxidize the PFCs gas, which is converted to carbon dioxide, fluorine (F ₂ ) and HF gas and removed. And since direct combustion method uses liquefied natural gas or hydrogen as fuel, it cannot be used in the existing processes without liquefied natural gas or hydrogen supply facilities, and also requires safety measures to cope with problems such as fire and explosion. As the PFCs to be treated are treated at high temperatures of 1,400 to 1,600 ° C, there is a problem in that the operating cost is increased. Additionally, by burning at high temperatures, a large amount of nitrogen oxides (NOx) are generated, which cause acid rain and photochemical smog. There is a problem that causes secondary air pollution.

In addition, the indirect heating method is a method of oxidizing and removing PFCs gas like a direct combustion method by raising the temperature of the reactor indirectly by using a heater, and is generally operated in a temperature range of 1,100 to 1,200 ° C, such as CF ₄ . Not only is it difficult to remove the hardly decomposable PFCs gas, and the high temperature heating shortens the life of the heater, making it difficult to produce continuous wafers.

In addition, the catalyst method removes PFCs gas at a low temperature range (800 ° C.) using a catalyst, but is converted to a solid oxide such as Al ₂ O ₃ , SiO _2, etc., which is introduced in an etching or CVD process. Since such solid oxides are deposited in the catalyst layer to block the flow path of the catalyst layer, it acts as a cause of increasing the pressure loss of the catalyst layer. When the acid gas generated after PFCs gas decomposition enters the catalyst layer, these acidic substances are catalysts. There is a problem that the adsorption and reaction to cause the irreversible degradation of the catalyst activity.

In addition, the plasma method includes a method of decomposing and removing PFCs gas using a high temperature plasma.

More specifically, the existing high temperature plasma scrubber is disclosed in FIG. 1.

The high temperature plasma scrubber is connected to the plasma torch unit 1 to generate a plasma flame in order to pyrolyze the PFCs gas introduced after etching and CVD cleaning, and the plasma torch unit 1 to supply the PFCs gas at high temperature. A reaction chamber part 2 provided for thermal decomposition of the furnace, and a quenching part for quenching the treated noxious gas by installing spray nozzles 6 on the left and right sides in order to spray water in a fine state from the lower end of the reaction chamber part ( 3) and a post-treatment unit (5) for treating water-soluble or acidic gas and particulate matter generated after decomposition with water injection nozzles and polling, and a water tank for storing and draining water and particulate matter from the quenching and post-treatment units. It is comprised by the part 4.

Such a scrubber using a high temperature plasma, when the harmful gas flowing into the plasma when the harmful gas is mixed with the plasma affects the flow of the plasma, it is difficult for the harmful gas to be sufficiently mixed with the plasma, a large amount of harmful gas In the case of processing, there is a problem more difficult to achieve a constant efficiency.

Accordingly, the first object of the present invention is to induce the harmful gas provided from the outside to flow in the opposite direction to the plasma flow, thereby increasing the reaction time between the plasma and the harmful gas, thereby improving the decomposition efficiency of the harmful gas. An object of the present invention is to provide a noxious gas treatment apparatus using countercurrent.

In addition, a second object of the present invention is to provide a counter flow between the plasma and the noxious gas to improve the decomposition efficiency of the noxious gas by the plasma by introducing a noxious gas in a direction opposite to the flow of the plasma so as to efficiently use the high temperature region of the plasma To provide a harmful gas treatment method used.

In order to achieve the first object of the present invention described above, in one embodiment of the present invention, the plasma generating means for generating a plasma by applying a voltage between the negative electrode and the positive electrode, and is connected to the rear end of the plasma generating means, from the outside Provided is a noxious gas treatment apparatus using a countercurrent of the plasma and noxious gas injecting the supplied noxious gas in a direction opposite to the plasma flow, and includes a counterflow chamber for discharging the noxious gas that has been plasma-treated to the outside.

In addition, in order to achieve the second object of the present invention, in one embodiment of the present invention in the noxious gas treatment method using the plasma generating means for generating a plasma by using the plasma forming gas, in the opposite direction to the flow of the plasma It provides a harmful gas treatment method using a counter-flow of plasma and harmful gas comprising the step of injecting harmful gas to decompose the harmful gas.

In the present invention, since harmful gas is injected in the opposite direction to the plasma flow, the plasma and the harmful gas are mixed more sufficiently than when the harmful gas is injected in the same direction as the plasma flow. Since the residence time of noxious gases is increased, the decomposition efficiency is improved. As described above, the present invention can efficiently utilize the high temperature region of the plasma.

In addition, the present invention facilitates the treatment of harmful gas components that need to be treated at a high temperature, or harmful gases that are not easy to be treated by a general treatment method, and are introduced into the plasma in a direction opposite to the flow of plasma. The horizontal range of can be expanded, so that a large amount of harmful gas can be treated at a time.

In addition, since it has an improved efficiency of harmful gas decomposition, it is possible to effectively decompose a larger amount of harmful gas using a small amount of energy, thereby saving energy and implementing an economical harmful gas treatment system.

1 is a schematic diagram showing a conventional plasma scrubber.
2 is a block diagram illustrating a plasma processing apparatus according to an embodiment of the present invention.
3 is a partially enlarged view illustrating a counterflow chamber according to an embodiment of the present invention.
Figure 4 is a schematic diagram for explaining the harmful gas guide tube according to the present invention.
5 to 9 are graphs showing the results of experiments using the apparatus for treating harmful gas of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail a noxious gas treatment apparatus (hereinafter referred to as "harmful gas treatment apparatus") using a counter flow of plasma and noxious gas according to preferred embodiments of the present invention.

2 is a block diagram for explaining a harmful gas treatment apparatus according to an embodiment of the present invention.

Referring to FIG. 2, the apparatus for treating noxious gas according to an embodiment of the present invention is connected to a plasma generating means 100 generating a plasma by applying a voltage between a negative electrode and a positive electrode, and a rear end of the plasma generating means 100. It is installed and includes a counter flow chamber 200 for injecting harmful gas introduced from the outside toward the plasma generating means 100 in the opposite direction of the flow of the plasma.

The combination of the plasma generating means 100 and the counterflow chamber 200 may be made in various ways, such as integral coupling, but, for example, it is preferable because the screw coupling may be easily separated from each other when necessary for component replacement. .

The harmful gas treatment apparatus according to the present invention is applicable to a pyrolysis treatment apparatus for treating infectious waste generated in a hospital, a food treatment apparatus, a gas scrubber, a radiation substance treatment apparatus, a special gas treatment apparatus, and the like. In the following description, the applied to the gas scrubber.

Toxic gases that are purged with the gas scrubber are perfluoride, chlorofluoro carbons, dioxin, furan, volatile organic compounds, or a plurality of mixtures thereof.

Hereinafter, each component will be described in more detail with reference to the drawings.

Referring to Figure 2, the harmful gas treatment apparatus according to an embodiment of the present invention includes a plasma generating means (100).

The plasma generating means 100 generates a plasma, for example, a plasma jet by applying a voltage between the negative electrode and the positive electrode, and forms a plasma of at least 1,000 ° C. using a plasma generating gas supplied from the outside. The plasma is discharged to the outside through a plasma discharge passage formed at a lower end of the plasma. In this case, as the plasma generating gas, argon, nitrogen, air, hydrogen, oxygen, or a gas in which a plurality of gases are mixed is used.

As shown in FIG. 3, the plasma generating means 100 forms a plasma generating space surrounding the negative electrode assembly 110 having a negative electrode to which a high voltage is applied, and the negative electrode, and when the high voltage is applied to the negative electrode. It may include a positive electrode assembly 120 having a positive electrode for generating a plasma jet between the negative electrode and a plasma generating gas injection path for injecting the plasma generating gas into the plasma generating space. In this case, a plasma discharge passage for discharging plasma to the outside is formed at the center of the lower end of the anode assembly 120. Here, the plasma discharge passage is preferably formed on the same horizontal axis as the negative electrode of the negative electrode assembly 110. In other words, the plasma discharge passage and the negative electrode are installed to face each other in a spaced state.

More specifically, an arc discharge is formed between the negative electrode and the positive electrode by a high voltage of at least 100 volts (V) applied to the cathode assembly 110, and argon introduced into the arc discharge region through the plasma generation gas injection path. The plasma generating gas such as nitrogen forms plasma. The plasma formed as described above becomes a plasma jet of 1,000 ° C. or more, and harmful gases that contaminate the global environment such as perfluoride introduced through the counterflow chamber 200 are decomposed to the high temperature plasma jet. In this case, the material of the negative electrode is preferably hafnium or tungsten to which thorium or yttrium is added.

Referring to Figure 2, the harmful gas treatment apparatus according to an embodiment of the present invention includes a counter flow chamber (200).

The counter flow chamber 200 is connected to the rear end of the plasma generating means 100 in which the plasma discharge passage is formed, and the harmful gas supplied from the outside is opposite to the flow of the plasma formed by the plasma generating means 100. It is injected toward the plasma generating means 100, and serves to discharge the harmful gas decomposed by the plasma to the outside. In this way, a harmful gas movement passage for moving the harmful gas provided from the outside is formed in the counter flow chamber 200, the harmful gas movement passage adjacent to the plasma generating means 100 from the plasma generating means 100 The discharged plasma jet forms a reaction section in which the plasma reacts with the noxious gas.

That is, in the present invention, harmful gas introduced from the outside is supplied to the counterflow chamber 200 instead of the plasma generating means 100, and the harmful gas decomposition treatment by plasma is performed in the counterflow chamber 200.

The counterflow chamber 200 may be formed in two forms as follows, but is not limited thereto.

In one embodiment, the counterflow chamber is connected to a rear end of the plasma generating means and a body portion having a harmful gas movement passage therein, and installed at a rear end of the body portion opposite to the plasma generating means, thereby generating the plasma generating means (100). It consists of a harmful gas supply pipe for supplying an external harmful gas toward the plasma formed by the), and the harmful gas discharge pipe is installed at the tip of the body portion in contact with the plasma generating means for discharging the harmful gas to the outside.

As another embodiment, the counterflow chamber 200 is connected to the rear end of the plasma generating means 100 is discharged plasma as shown in Figure 3 and the harmful gas guide pipe which is formed through the longitudinal passage ( 210 and an inlet of the noxious gas guide tube 210 connected to the plasma generating means 100 and facing the rear end of the plasma generating means so as to form an external passage surrounding the noxious gas guide tube 210. And a harmful gas supply pipe 222 receiving harmful gas from the outside at a position corresponding to the harmful gas discharge pipe 224 for discharging the harmful gas plasma treated at a position corresponding to the outlet of the harmful gas guide tube 210. The housing 220 is provided, and the blocking plate 230 is provided between the harmful gas supply pipe 222 and the harmful gas discharge pipe 224 to fractionate the external passage.

Here, the open top surface of the harmful gas guide pipe 210 forms an outlet of harmful gas, the open bottom surface forms an inlet of harmful gas, the harmful gas supply pipe 222 and the harmful gas discharge pipe 224 One or more circumferences of the housing 220 are provided.

The noxious gas guide tube 210 may be formed in a cylindrical structure, a vertical narrow light cylindrical structure, or a vertical narrow light cylindrical structure as shown in FIG. 4. Herein, the cylindrical structure has a constant inner diameter (a), and the upper and lower light cylindrical structures have a larger inner diameter toward the lower side of the axis, and the lower narrow light cylindrical structure has a smaller inner diameter as the lower side thereof. That is, the upper narrow light cylindrical structure has an effective diameter b of the outlet smaller than the effective diameter b 'of the inlet, and the lower narrow light cylindrical structure has an effective diameter c of the outlet. Has a structure larger than).

As such, the cross section of the noxious gas guide tube 210 is preferably circular, but is not necessarily limited thereto, and may be rectangular or hexagonal. In addition, the effective diameter of the noxious gas guide tube 210 may be formed in 10 to 200mm, in order to process a large amount of harmful gas is preferably 50 to 200mm. Here, the effective diameter refers to the average diameter of the internal shape of the cross section of the noxious gas guide tube 210. That is, by adjusting the cross-sectional area of the harmful gas guide pipe 210 it can form an optimal reaction temperature range.

The noxious gas guide tube 210 has a replaceable structure, so when there is a need to replace the noxious gas guide tube 210 due to long-term use, only the noxious gas guide tube 210 may be replaced.

And the housing 220 is detachably coupled by a blocking plate 230 using a flange or the like. For example, the housing 220 includes an upper housing and a lower housing, the outer passages of the upper housing and the lower housing are sealed to each other by the blocking plate 230, and the upper housing and the lower housing are closed by the blocking plate 230. It is fastened to each other by screwing. By using such a screw coupling, the upper housing and the lower housing can be easily separated from each other when the harmful gas guide tube 210 needs to be replaced.

As such, the counterflow chamber 200 is formed in a double passage structure by an inner passage of the noxious gas guide tube 210 and an inner passage of the housing 220 corresponding to the outer passage of the noxious gas guide tube 210. The harmful gas introduced into the counter flow chamber 200 through the noxious gas supply pipe 222 may be an external passage of the noxious gas guide tube 210, an internal passage of the noxious gas guide tube 210, and noxious gas. After passing through the outer passage of the guide pipe 210 is discharged to the outside through the harmful gas discharge pipe 224.

In other words, since the counter flow chamber 200 is formed so that the noxious gas guide pipe 210 is not directly communicated with the noxious gas supply pipe 222 and the noxious gas discharge pipe 224, the noxious gas guide pipe 210 is formed by plasma. If it is damaged can be used to replace only the harmful gas guide pipe (210).

Referring to Figure 2, the harmful gas treatment apparatus according to an embodiment of the present invention may further include a quench pipe (300).

The quench pipe 300 is sprayed to spray water to quench the harmful gas introduced from the counter flow chamber 200 and to treat water-soluble gas, acid gas and particulate matter in the harmful gas; It is preferable to have one or more of the same water spraying device (310).

2, the harmful gas treatment apparatus according to an embodiment of the present invention may further include a waste water storage means (400).

The waste water storage means 400 is installed on one side of the quenching pipe 300 to store waste water sprayed from the water spraying device 310 to adsorb harmful gases.

The wastewater storage means 400 may be provided with a pump (not shown) for discharging the wastewater to the outside when the stored wastewater reaches a predetermined level. In addition, the wastewater storage means 400 may be provided with a sensor (not shown) for detecting the level of the stored wastewater. That is, the sensor detects the level of the stored wastewater and reaches a predetermined level to transmit a driving signal to the pump to operate the pump.

2, the harmful gas treatment apparatus according to an embodiment of the present invention may further include a post-processing unit 500.

The after-treatment unit 500 is a secondary treatment of the water-soluble gas, acidic gas and particulate matter treated primarily in the quench pipe 300, water spray nozzle 510, such as a spray for spraying water (510) It is preferable to have a plurality).

The post-treatment unit 500 is preferably laminated to the bottom of the water spray nozzle 510 polling 520 to increase the contact surface area for effective treatment of the sprayed water and water-soluble gas, acid gas and particulate matter. Do.

On the other hand, the present invention provides a method for treating noxious gas (hereinafter referred to as 'hazardous gas processing method') using the above-described plasma generating means and using plasma and noxious gas countercurrent.

The harmful gas treatment method according to an embodiment of the present invention comprises the first step of collecting the harmful gas from the source of harmful gas, the harmful gas so that the collected harmful gas is injected in the opposite direction to the flow of the plasma generated from the plasma generating means Injecting toward the plasma generating means includes a second step of decomposing the inlet gas, and a third step of discharging the decomposed harmful gas to the outside.

In the second step, the harmful gas collected from the noxious gas source is not directly injected into the plasma generator, but is injected into the rear end of the counterflow chamber spaced apart from the plasma generator to supply the noxious gas in a direction opposite to the plasma flow. Step. Through this process, no harmful gas is injected in the same direction as the plasma generated from the plasma generator, and the harmful gas is injected in a direction opposite to the plasma flow to induce a collision between the plasma and the noxious gas. That is, since the reaction between the plasma and the harmful gas flowing in the opposite direction is used, the high temperature region of the plasma is diffused, and the residence time of the harmful gas is increased in the high temperature region where the plasma and the harmful gas are mixed, so that the decomposition efficiency of the harmful gas is improved. This is improved.

Further, in the second step, the supply flow rate of the plasma forming gas supplied to the plasma generating means, the output of the plasma generating means, or in order to achieve a constant decomposition efficiency of harmful gases in accordance with the injection rate of harmful gases into the counter flow chamber The process of controlling all of these can be carried out.

In addition, in the second step, the effective diameter of the noxious gas guide tube for guiding the noxious gas in a direction opposite to the flow of plasma in order to achieve a constant decomposition efficiency of noxious gas according to the injection rate of the noxious gas into the counterflow chamber. The process of controlling the noxious gas treatment area may be performed by adjusting the shape, shape, or both.

In the following embodiments, when the temperature distribution is observed as simulation data of the temperature distribution in the counterflow chamber according to various conditions, the degree of harmful gas decomposition in the counterflow chamber may be determined.

Temperature distribution according to plasma generating means (torch)

Example 1

Plasma generating means (torch 1) having an electrode length (from the cathode to the plasma discharge passage) of 40 mm and a diameter of the plasma discharge passage of 14 mm was used. The plasma is generated by supplying power of 7.84 kW, and CF ₄ is injected at 200 lpm as a noxious gas into a counterflow chamber having an effective diameter (inner diameter) of the noxious gas guide tube at 100 mm to react with the noxious gas. The range of the high temperature region formed inside the harmful gas guide tube was observed. The result is shown on the left side of a of FIG.

[Example 2]

Under the same experimental conditions as in [Example 1], the range of the high temperature region was observed, but 12.02 kW was supplied instead of 7.84 kW of power to the plasma generating means. The results are shown on the right side of a of FIG.

[Example 3]

A plasma generating means (torch 2) having an electrode length of 84 mm and a diameter of the plasma discharge passage 20 mm was used. The plasma is generated by supplying electric power 12.49 kW, and CF ₄ is injected at 200 lpm as a noxious gas into a counterflow chamber having an effective diameter (inner diameter) of the noxious gas guide tube at 100 mm, thereby reacting with noxious gas. The range of the high temperature region formed inside the noxious gas guide tube was observed. The results are shown on the left side of b in FIG.

Example 4

The range of the high temperature region was observed under the same experimental conditions as in [Example 3], but 14.04 kW was supplied instead of 12.49 kW of power to the plasma generating means. The result is shown to the right of b in FIG.

As shown in FIG. 5, when 200 lpm of noxious gas was injected into the noxious gas treatment device, a wide high temperature region was observed at the highest input power in [Example 4]. And when comparing [Example 2] and [Example 3] in which similar input power was used, the case of [Example 2] was more deeply penetrated into the inside of the noxious gas guide tube due to the narrow noxious gas discharge passage. In addition, due to the harmful gas introduced in the direction opposite to the flow direction of the plasma, the temperature distribution inside the harmful gas guide tube showed a similar tendency to that of [Example 2] and [Example 3].

Temperature distribution according to harmful gas injection speed

[Example 5]

Under the same experimental conditions as in [Example 2], the range of the high temperature region was observed, but instead of the harmful gas at 200 lpm, the harmful gas was injected at 50 lpm. The results are shown on the left side of a of FIG. 6.

[Example 6]

Under the same experimental conditions as in [Example 2], the range of the high temperature region was observed, but instead of the harmful gas at 200 lpm, the harmful gas was injected at 100 lpm. The result is shown to the right a of FIG.

[Example 7]

Under the same experimental conditions as in [Example 2], the range of the high temperature region was observed, but instead of injecting the harmful gas at 200 lpm, the harmful gas was injected at 300 lpm. The results are shown on the right side b of FIG. 6 (the b left temperature distribution of FIG. 6 is the result according to Example 2 and is shown for comparison).

As shown in FIG. 6, when the noxious gas is 100 lpm or less as in [Example 5] and [Example 6], the temperature near the plasma generating means (horizontal axis direction) is [Example 2] and [Example] 7], the area rising more than 2000 K showed a wide tendency.

Temperature distribution according to the diameter of harmful gas guide pipe

[Example 8]

Observe the range of the high temperature region under the same experimental conditions as in [Example 2] above, but instead of using a counterflow chamber having an effective diameter of 100 mm in the noxious gas guide tube, the countercurrent having an effective diameter of the nominal gas guide tube in 25 mm. The chamber was used. The results are shown on the left side of a in FIG.

[Example 9]

Observe the range of the high temperature region under the same experimental conditions as in [Example 2] above, but instead of using the counterflow chamber having an effective diameter of 100 mm in the noxious gas guide tube, the countercurrent having an effective diameter of the noxious gas guide tube in the range of 50 mm. The chamber was used. The result is shown on the right side of a of FIG.

[Example 10]

Observe the range of the high temperature region under the same experimental conditions as in [Example 2] above, but instead of using a counterflow chamber having an effective diameter of 100 mm in the noxious gas guide tube, the countercurrent having an effective diameter of the noxious gas guide tube is 200 mm. The chamber was used. The result is shown on the right side b of FIG. 7 (the b left temperature distribution of FIG. 7 is a result according to Example 2 and is shown for comparison).

As shown in FIG. 7, when the effective diameter of the noxious gas guide tube is smaller than 50 mm, it was observed that the plasma flame does not penetrate into the noxious gas guide tube and becomes unstable due to the rapidly injected noxious gas. When the diameter of the noxious gas guide tube is 200 mm, the temperature near the plasma generating means (horizontal axis direction) rises to about 2,000K, but the plasma penetrates sufficiently to the center of the noxious gas guide tube, thereby providing high noxious gas treatment efficiency. I could expect.

Temperature distribution according to the shape and diameter of the harmful gas guide tube 1

[Example 11]

Observing the range of the high temperature region under the same experimental conditions as in [Example 2] above, the effective diameter of the noxious gas guide tube is 20-50 mm instead of using a counterflow chamber having an effective diameter of the nominal gas guide tube of 100 mm. Counterflow chambers were used. The results are shown on the right side a of FIG. 8 (the a left temperature distribution of FIG. 8 is the result according to Example 2, and is shown for comparison).

[Example 12]

Observing the range of the high temperature region under the same experimental conditions as in [Example 2] above, the effective diameter of the noxious gas guide tube is 50-100 mm instead of using a counterflow chamber having an effective diameter of the nominal gas guide tube of 100 mm. Counterflow chambers were used. The result is shown to the left of b in FIG.

[Example 13]

Observing the range of the high temperature region under the same experimental conditions as in [Example 2] above, the effective diameter of the noxious gas guide tube is 100-200mm instead of using a counterflow chamber having an effective diameter of the nominal gas guide tube of 100 mm. Counterflow chambers were used. The result is shown on the right side b of FIG.

As shown in FIG. 8, when the effective diameter of the noxious gas guide tube is 100 mm and the effective diameter of the noxious gas guide tube is 100-200 mm, the effective diameter of the side closer to the plasma generating means is measured. It was found that the distribution was determined. Therefore, it was judged that the plasma flame penetrated the inside of the noxious gas guide tube best when the effective diameter near the plasma generating means was 100 mm.

Temperature distribution according to the shape and diameter of the noxious gas guide tube 2

Example 14

Observing the range of the high temperature region under the same experimental conditions as in [Example 2] above, the effective diameter of the harmful gas guide tube is 50-20 mm instead of using a counterflow chamber having an effective diameter of 100 mm. Counterflow chambers were used. The results are shown on the right side a of FIG. 9 (a left temperature distribution of FIG. 9 is the result according to Example 2 and is shown for comparison).

Example 15

Observing the range of the high temperature region under the same experimental conditions as in [Example 2] above, the effective diameter of the noxious gas guide tube is 100-50 mm instead of using a counterflow chamber having an effective diameter of the nominal gas guide tube is 100 mm. Counterflow chambers were used. The result is shown to the left of b in FIG.

[Example 16]

Observing the range of the high temperature region under the same experimental conditions as in [Example 2] above, the effective diameter of the noxious gas guide tube is 200-100 mm instead of using a counterflow chamber having an effective diameter of the nominal gas guide tube of 100 mm. Counterflow chambers were used. The result is shown to the right of b in FIG.

As shown in Fig. 9, the temperature distribution of the noxious gas guide tube used in [Example 14] to [Example 16] also has an important effect on the effective diameter of the noxious gas guide tube close to the plasma generating means. It was confirmed. That is, when the effective diameter near the plasma generating means is 200 mm, it was judged that the plasma flame penetrated the inside of the noxious gas guide tube best.

As described above, it was analyzed that the present invention is advantageous in that a small diameter of the plasma discharge passage is advantageous in generating a plasma jet having a high radial gradient and having a high temperature in a relatively radial direction.

At a similar output of about 12 kW, a plasma discharge passage having a diameter of 14 mm (torch 1) generates a relatively high-speed plasma and infiltrates the plasma deeply into the noxious gas guide tube, thereby increasing the diameter of the plasma discharge passage. Economical and effective disassembly can be expected than the case of 20 mm (torch 2).

In addition, in the reaction section, since the plasma flame extends in the radial direction, there is a fear of damaging the harmful gas guide tube. On the other hand, if the amount of harmful gas is too large, it is not possible to expect a sufficient mixing of the harmful gas and plasma, so the optimum harmful gas flow rate conditions should be determined according to the conditions of the plasma generating means and the counterflow chamber.

In addition, in the case of the noxious gas guide tube having a cylindrical structure, as the effective diameter increases, the plasma can be expected to penetrate deeply into the noxious gas guide tube to provide an improved effective gas treatment efficiency.

In addition, since the plasma characteristics are determined by the effective diameter of the noxious gas guide tube close to the plasma generating means, even if the noxious gas guide tube having the cylindrical narrow beam structure is applied, It is preferable to use a noxious gas guide tube and optimize the effective diameter of the noxious gas guide tube according to the operating conditions of the plasma generating means and the noxious gas injection conditions.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It can be understood that it is possible.

100: plasma generating means 110: negative electrode assembly
120: anode assembly 200: counterflow chamber
210: harmful gas guide tube 220: housing
222: harmful gas supply pipe 224: harmful gas discharge pipe
230: blocking plate 300: quench piping
310: water spray device 400: waste water storage means
500: after-treatment unit 510: water spray nozzle
520 polling

Claims (7)

Plasma generating means for generating a plasma by applying a voltage between the negative electrode and the positive electrode; And
It is connected to the plasma generating means, injecting the harmful gas supplied from the outside in the opposite direction to the plasma flow, and the counter flow of the plasma and harmful gas including a counter flow chamber for discharging the harmful gas discharged to the outside Harmful gas treatment device used. The method of claim 1, wherein the counterflow chamber is
A harmful gas guide tube connected to a rear end of the plasma generating means through which the plasma is discharged, and an inner passage formed;
It is connected to the plasma generating means so as to form an external passage surrounding the noxious gas guide tube, and receives noxious gas from the outside at a position corresponding to the inlet of the noxious gas guide tube facing the rear end of the plasma generating means. A housing provided with a harmful gas supply pipe, the housing having a harmful gas discharge pipe for discharging the harmful gas plasma treated at a position corresponding to the outlet of the harmful gas guide pipe, and
The harmful gas treatment device using a counter-flow of plasma and harmful gas, characterized in that it is provided between the harmful gas supply pipe and the harmful gas discharge pipe consisting of a blocking plate for fractionating the external passage. The method of claim 2, wherein the harmful gas guide pipe
A harmful gas treatment apparatus using a counter flow of plasma and noxious gas, characterized in that formed in any one of a cylindrical structure, a vertical narrow light cylindrical structure, a lower narrow flat light cylindrical structure. The method of claim 2, wherein the harmful gas guide pipe
An apparatus for treating noxious gas using a counter flow of plasma and noxious gas, the effective diameter of which is 50 to 200 mm. In the noxious gas treatment method using the plasma generating means for generating a plasma by using the plasma forming gas,
Injecting harmful gas in a direction opposite to the flow of the plasma to decompose the harmful gas and the harmful gas treatment method using a counter flow of the plasma and harmful gas. The method of claim 5, wherein
By using the counter flow of the plasma and harmful gas, the harmful gas treatment region is controlled by controlling the effective diameter, the shape, or both of the harmful gas guide tubes for guiding the harmful gas in the opposite direction to the flow of the plasma. Hazardous Gas Treatment Method. The method of claim 5, wherein
The harmful gas treatment method using the counter flow of the plasma and harmful gas, characterized in that for controlling the harmful gas treatment area by adjusting the injection rate of the harmful gas.

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