Patent Application
20130305970
1. Field of the Invention
The present invention relates to a scrubber, and more particularly, to a plasma scrubber for burning toxic gas using plasma in combination with hydrogen and oxygen, which are produced by electrolysis.
2. Description of the Prior Art
The use of toxic gases has increased with industrialization, and techniques or apparatuses for treating toxic gases have been developed. Particularly, toxic gases which are generated during the production of large amounts of products such as semiconductor devices or flat panel displays are generally treated by combustion apparatuses in which they are burned with plasma.
The plasma combustion apparatus is an apparatus of burning toxic gas by the interaction of a cathode and an anode, and the toxic gas burned in the combustion apparatus is then discharged after separate treatment.
However, the above-described plasma scrubber according to the prior art has the following disadvantages described below.
The plasma combustion apparatus is ideal in that fewer byproducts are generated, but it has a problem in that power consumption increases rapidly with an increase in the flow rate of the gas being treated.
Moreover, in the conventional method, nitrogen must be used to dilute the concentration of toxic gas.
In addition, when a pipeline for supplying an auxiliary gas such as hydrogen or oxygen is used, there is a problem in that the risk of fire or explosion increases, because it is difficult to control the supply of hydrogen or oxygen at a constant level.
Accordingly, the present invention has been made in view of the above-described problems occurring in the prior art, and it is an object of the present invention to reduce the increase of power consumption resulting from an increase in the flow rate of the gas being treated.
Another object of the present invention is to provide a combustion apparatus for supplying auxiliary gases capable of increasing treatment temperature.
In accordance with a preferred exemplary embodiment of the present invention, a scrubber of the present invention includes a main unit including: a first body for burning toxic gas using a flame generated by a cathode electrode and an anode electrode, and auxiliary gases; and a second body which is connected with the first body and includes an in-chamber for treating the toxic gas burned in the first body.
The scrubber of the present invention preferably includes an electrolysis unit serving to produce hydrogen and oxygen by the electrolysis of water and to supply the produced hydrogen and oxygen as auxiliary gases to the main unit.
Preferably, the second body includes a plurality of middle chambers located around the in-chamber, and a movement pathway is formed in the plurality of middle chambers such that the toxic gas introduced through the in-chamber is discharged to the bottom of the second body through the plurality of middle chambers.
The electrolysis unit of the present invention preferably includes: an electrolysis tank including a first electrode and a second electrode; a power supply unit for supplying power to the electrolysis tank; and a stabilizer for stabilizing gases produced in the electrolysis tank.
Preferably, the first electrode is made of a titanium metal, and the second electrode is made of a cold-rolled stainless steel metal.
The cathode electrode that is used in the scrubber of the present invention preferably includes a tungsten portion provided at the front end of the cathode electrode, and a copper portion connected to the tungsten portion and having a cooling water channel formed therein, in which the tungsten portion is screw-coupled with the copper portion such that it does not come in contact with cooling water flowing through the cooling water channel of the copper portion.
The anode electrode that is used in the scrubber of the present invention preferably includes: a first anode electrode which is provided in the first body and into which a plasma-forming gas introduced into the first body is introduced; and a second anode electrode which is connected with the first anode electrode and has a magnetic portion provided on the inner circumference thereof and in which a reaction chamber for generating a flame by plasma is provided at the central portion.
The first anode electrode of the present invention preferably includes: a flange portion inside which the cathode electrode is located at the center and at the circumference of which is formed plasma-forming gas inlet holes through which the plasma-forming gas is introduced; and an electrode body which communicates with the flange portion and is connected with the second anode electrode and at the circumference of which a cooling water channel is formed.
A dual chamber structure in a scrubber for treating waste gas according to the present invention preferably includes an in-chamber for burning toxic gas using a flame generated by a cathode electrode and an anode electrode, and auxiliary gases.
The dual chamber structure in the scrubber of the present invention preferably further includes a plurality of middle chambers configured such that they are located around the in-chamber and communicate with the in-chamber so as to discharge the toxic gas to the outside while maintaining a heat source.
Additional advantages and features of the present invention will be more clearly understood from the following description and the accompanying drawings.
Hereinafter, a preferred embodiment of the present invention will be described in further detail with reference to the accompanying drawings.
The scrubber of the present invention is configured such that it burns toxic gas by using auxiliary gases such as hydrogen and oxygen, which are supplied from an electrolysis unit, whereby combustion heat caused by plasma is used in combination with high energy generated by the combustion of hydrogen and oxygen, thereby reducing power consumption and treatment temperature.
As shown in
To the side of the first body 11 there is connected an inlet pipe 13 through which toxic gas is introduced from the outside. Toxic gas that is introduced from the outside through the inlet pipe 13 may be introduced into the body 11. The inlet pipe 13 may be formed spirally so as to form an eddy of toxic gas.
The top of the first body 11 is provided with an insulating cap 15 (see
The tig setup 20 functions to allow the cathode electrode 27 and an anode electrode 33 to react with each other by way of power supplied from the outside. As shown in
At the point at which the tig body 21 is connected with the first body 11, there is provided a cathode electrode control unit 25 for controlling the protrusion length of the cathode electrode 27. The cathode electrode control unit 25 is screw-coupled to a thread formed on the inside of the first body 11. Thus, when the tig body 21 is rotated, the protrusion length of the cathode electrode 27 connected to the electrode chuck 23 of the tig body 21 can be controlled.
In other words, when the cathode electrode 27 is worn out so as to be spaced apart from the anode electrode 33 so that ignition is not easily initiated, the distance of the cathode electrode 27 from the anode electrode 33 can be adjusted by controlling the length of the cathode electrode 27 without having to replace the cathode electrode 27.
However, in the cathode electrode according to the prior art, the tungsten portion came in direct contact with water. Thus, in some cases, the tungsten portion was damaged or spaced apart from the anode electrode such that electric discharge did not occur. To solve this problem, the cathode electrode 27 according to the present invention is configured such that water comes in contact only with the copper portion.
As shown in
A cooling water channel 27f is formed in the copper portion 27c so that cooling water moves through the cooling water channel 27f to cool the cathode electrode 27. Herein, the tungsten portion 27t is preferably formed at the end portion of the copper portion 27c so that it does not come in direct contact with cooling water.
Each of the tungsten portion 27t and the copper portion 27c may be formed in a rod shape having a diameter of about 12 mm. The tungsten portion 27t may be formed to have a length of about 8 mm, and the copper portion may be formed to have a length of about 52 mm.
Furthermore, the tungsten portion 27t and the copper portion 27c are screw-coupled to each other, and after screw coupling, they are welded to each other in order to improve heat transfer. In addition, the cooling water channel 27f which is formed in the copper portion 27c may be formed to have a width of about 7.5 mm and a depth of about 44 mm.
The front end of the cathode electrode 27 configured as described above is made of tungsten having high heat resistance, and the back end is made of copper having good heat conductivity, whereby the heat resistance and electric discharge effects of the cathode electrode 27 can be maximized. Further, because the cooling water channel is formed only in the copper portion 27c, the tungsten can be prevented from being damaged by water.
In addition, in the insulating cap 15 in which the cathode electrode 27 is placed, a plasma-forming gas channel 31 (see
Below the insulating cap 15, there is formed a reaction chamber 35 that provides a space in which the cathode electrode 27 and the anode electrode 33 react with each other. Around the reaction chamber 35, there is provided the anode electrode 33 that reacts with the cathode electrode 27.
For high voltage and low power, the anode electrode 33 is divided into two stages: a first anode electrode 33a and a second anode electrode 33b. The first anode electrode 33a and the second anode electrode 33b are coupled to each other.
As shown in
Further, the center inside the flange portion 33af is formed to be perforated. Preferably, the inner circumferential surface of the flange portion 33af is tapered downward at an angle of about 9-12°.
Due to the tapered angle of the inner circumferential surface of the flange portion 33af, a plasma-forming gas which is introduced through the plasma-forming gas inlet holes 33ah forms an eddy while it is introduced consistently into the flange portion 33af. In addition, in the center inside the flange portion 33af, there is placed the end of the cathode electrode 27 that reacts with the anode electrode 33.
As shown in
As shown in
As shown in
As shown in
Below the reaction chamber 35, there is formed a combustion chamber 39 in which toxic gas is burned. Toxic gas introduced through the inlet pipe 13 is burned in the combustion chamber 39.
To the first body 11 to which the inlet pipe 13 is connected, there is connected an auxiliary gas pipe 40 through which auxiliary gases are introduced from an electrolysis unit 100 to be described below. Auxiliary gases such as hydrogen and oxygen are introduced through the auxiliary gas pipe 40 to promote the combustion of toxic gas in the combustion chamber 39.
To the lower side of the first body 11, there is connected a second body 50 for burning toxic gas by a flame and cooling the burned toxic gas or removing toxic substances from the toxic gas.
As shown in
The in-chamber 51 is provided in the second body 50 to form a dual chamber. Toxic gas burned in the first body 11 is additionally burned in the in-chamber 51. Because the entire chamber consists of a dual chamber due to the in-chamber 51, a plasma flame can be cooled indirectly and can move downward.
Between the second body 50 and the in-chamber 51, there may be provided a plurality of middle chambers 60. The middle chambers 60 serve to increase the length of the movement pathway of toxic gas which is burned in the in-chamber 51, thereby completely burning the toxic gas and reducing the discharge of the toxic gas.
As shown in
The second middle chamber 63 surrounds the first middle chamber 61. A portion of the upper portion of the second middle chamber 63 communicates with the first middle chamber 61, and a portion of the lower portion communicates with the portion below the first middle chamber 61, that is, the lower portion of the second body 50.
Toxic gas introduced into the bottom of the second middle chamber 63 is discharged to an external water tank (not shown) through an outlet 57 provided at the bottom of the second body 50.
On the outermost surface of the second body 50, a cooling chamber 59 for cooling the outer surface of the second body 50 may be provided. The cooling chamber 59, through which cooling water introduced through a cooling water pipe 55 from the outside flows, serves to cool the outer surface of the second body 50.
Below the second body 50, there may be provided a water treatment unit 70 for removing toxic substances from toxic gas which is discharged through the outlet 57. The water treatment unit 70 may be connected with the bottom of the second body 50 and may be connected with an external water tank.
The water treatment unit 70 serves to spray water upward toward the second body 50 so as to remove toxic substances from toxic gas.
Toxic gas passed through the second body 50 is discharged through the outlet 57 provided at the bottom of the second body 50 and is received in a water tank, after which it is treated by a separate additional treatment apparatus or exhaust apparatus.
The main unit 10 configured as described above is connected with an electrolysis unit 100 which generates hydrogen and oxygen by electrolysis and supplies the generated hydrogen and oxygen as auxiliary gases. Hydrogen and oxygen which are produced in the electrolysis unit 100 are introduced into the main unit through an auxiliary gas pipe 40.
Hydrogen and oxygen which are produced by the electrolysis of water in the electrolysis unit 100 are supplied as auxiliary gases, and high energy generated by combustion of hydrogen and oxygen acts in combination with combustion heat caused by plasma, thereby increasing treatment temperature and reducing power consumption.
As shown in
The electrolysis tank 110 comprises a first electrode 111, which may be made of 99.7% titanium (Ti), and a second electrode 113 which may be made of a stainless steel metal. More specifically, the second electrode 113 is preferably made of STS316L as described in KSD 3698 (cold-rolled stainless sheet and wire).
The first electrode 111 and the second electrode 113 are spaced apart from each other at an interval of about 2 mm. When electric current is applied to the first electrode 111 and second electrode 113 filled with water, oxygen will be generated in the first electrode, and hydrogen will be generated in the second electrode 113.
In addition, hydrogen and oxygen which are generated in the electrolysis tank 110 move to a plurality of stabilizers 130 through transfer pipes 140. The stabilizers 130 serve to prevent explosion from occurring due to the generated hydrogen and oxygen and to supply the generated hydrogen and oxygen in a stable manner and functions as a flashback arrestor.
The stabilizers 130 are configured such that the transfer pipe 140 extending from the electrolysis tank 110 is immersed in water in the stabilizer 130 and the other transfer pipe 140 is not immersed in water. Thus, hydrogen and oxygen which are generated in the electrolysis tank 110 are supplied to water so as to prevent explosion from occurring due to excessive concentration of hydrogen and oxygen. Hydrogen and oxygen, dispersed into air from water in the stabilizer 130, move to the next stabilizer 130, and thus a stable supply of hydrogen and oxygen is possible.
Hydrogen and oxygen, passed through the stabilizers 130, are supplied to the main unit 10 in which they are used as auxiliary gases for burning toxic gas, thereby reducing power consumption and increasing treatment temperature.
A titanium metal and a cold-rolled stainless steel metal, which are used in the electrolysis tank 110 for the generation of hydrogen and oxygen, have high electrolysis ability, and thus can resolve the financial issues resulting from the use of platinum or stainless steel according to the prior art.
For example, when a power supply unit 120 that outputs a DC voltage of 12 V using alternating current is used, about 1 LPM of hydrogen and oxygen can be generated from water which is electrolyzed by a DC voltage of 12 V and a current of 20 A. Tables 1 to 3 below show efficiency as a function of power consumption in the case in which such hydrogen and oxygen are used as auxiliary gases.
As can be seen in Tables 1 to 3 above, power consumption in the present invention is 14 Kw corresponding to 63% of that in the conventional method, and the method of the present invention can treat 90% or more of 200 LPM of CF4 gas at a power of 18 Kw.
In addition, Table 4 below shows treatment efficiency as a function of the usage of auxiliary gases (CDA) such as hydrogen and oxygen, and Table 5 below shows chamber temperature as a function of DC voltage.
From the results in Table 4 above, efficiencies obtained when the auxiliary gases are used in amounts of 0 LPM, 5 LPM and 10 LPM can be seen. As can be seen in Table 5 above, an increase in DC voltage leads to an increase in chamber temperature.
Although Table 4 above describes that the auxiliary gases are supplied in an amount of 0-10 LPM, the auxiliary gases may preferably be supplied in an amount of 5-20 LPM.
The reaction of carbon tetrafluoride (CF4), a toxic gas, in the scrubber configured as described above, occurs according to the following reaction formula 1.
CF4+H2+O2→CO2+2HF2 Reaction formula 1
H2 and O2, which are required to treat CF4, are obtained at a temperature of 3,000° C. or higher, and high power needs to be maintained in order to obtain this temperature. However, in the scrubber of the present invention, toxic gas such as CF4 can be treated with low power, because the toxic gas is treated by introducing hydrogen and oxygen, generated by electrolysis, into the chamber.
As described above, in the scrubber of the present invention, a high combustion rate can be achieved even with relatively low power by a combination of high energy, obtained by the hydrogen and oxygen produced by electrolysis, with the combustion heat caused by plasma.
In addition, according to the present invention, toxic gas can be more efficiently treated by supplying hydrogen and oxygen to increase treatment temperature.
Because H2 and O2 which are required to treat CF4 gas are obtained at high temperature, high power needs to be maintained in order to obtain this temperature. However, in the scrubber of the present invention, CF4 can be easily treated with low power, because the hydrogen and oxygen generated by electrolysis are used.
Although the preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2012-0053853 | May 2012 | KR | national |
