KR20010000569A - Oxygen enriched PFC scrubbing system - Google Patents

Abstract

PURPOSE: A system for processing perfluorinated compounds(PFC) using an oxygen incubating method is provided to eliminate the PFC, by using oxygen-incubated air and double-pipe type helical flame, and by purifying exhausted gas through an exhaust gas processing apparatus. CONSTITUTION: A system for processing perfluorinated compounds(PFC) using an oxygen incubating method comprises an oxygen incubating supply apparatus(11), a premixing apparatus(13), a combustion chamber(15), an inner combustion chamber(16) and an exhaust gas processing apparatus. The oxygen-incubated separating and supplying apparatus generates high density oxygen-incubated air. The premixing apparatus respectively premixes fuel with air and fuel with PFC. The combustion chamber forms helical flame, composed of a double-pipe type. A material of a metal net or honeycomb type is inserted into the inner combustion chamber which increases a flame temperature and radiant heat. The exhaust gas processing apparatus wet-processes exhausted gas after processing a combustion of the PFC.

Description

Oxygen enriched PFC scrubbing system

The present invention relates to a method and apparatus for treating exhaust gas containing a fluorine-containing compound (PFC). The invention also relates to a method of removing harmful reactants after oxygen enrichment and combustion treatment of off-gases using a separator.

Fluorine-containing compounds are gases used for etching, chemical vapor deposition (CVD) and equipment cleaning in semiconductor manufacturing processes. Representative PFC gases are CF ₄ , C ₂ F ₆ , C ₃ F ₈ , CHF ₃ , NF ₃ and SF ₆ . This PFC gas is known as a gas that causes the global warming phenomenon that causes the global greenhouse effect. The global warming index (GWP) of these gases is a very stable compound that is about 6000 to 24,000 times higher than carbon dioxide. Accordingly, countries around the world have agreed to voluntarily reduce the amount of PFC gas emissions, and it is inevitable to reduce the amount of emissions through the removal device such as the present invention, which was previously discharged without treatment. The conventional method of treating harmful gases in the semiconductor manufacturing process is to treat harmful gases by flowing them into a high-temperature furnace using electric heating wire, which is not applicable to PFC gas treatment due to the enormous cost of electricity and the limit temperature of high temperature maintenance. It is partly applied to the treatment of less stable HFC compounds. In addition, the PFC treatment technology by the combustion technology can be applied to a special design technology. In other words, combustors applied to other products, such as boilers, cannot first increase the flame temperature to the extent that PFC gas can be processed, and the addition of hydrogen is very reluctant to use in semiconductor manufacturing plants due to the easy method or the risk of storage and use. It is impossible. Therefore, the application of the membrane-type oxygen enrichment apparatus, which is attached in the same apparatus as the present invention and which guarantees the safety and convenience of use, is the best method. Other methods include the separation and recovery of PFC gas in the exhaust gas using adsorbents or membranes, but they are not practical due to technical limitations and degradation of separation efficiency, and are difficult to commercialize for the time being. Therefore, the most suitable technique for treating such PFC is combustion treatment technique. However, it is known that PFC gas decomposes only at very high temperatures above 100-1200 ° C. Therefore, in order to combust the PFC gas, a special high temperature combustion technology and a residence time increase technology in which the PFC can be in contact with the flame for a long time are key. In order to achieve this, the present invention invented an oxygen-enriched air supply using a double tube type high efficiency combustor and a separator and a high temperature combustion method using the same.

The present invention has an object of the present invention to increase the temperature of the flame to 1000 ℃ or more by using the separation air to increase the concentration of oxygen in the air by using the separation membrane to solve the above problems. In addition, the structure of the combustion chamber is designed as a double-tubular combustion chamber composed of an outer tube and an inner tube to extend the flame residence time and to pre-mix fuel, air, fuel, and PFC gas in a premixing chamber to achieve an efficient high temperature flame. Accordingly, an object of the present invention is to provide a method and apparatus for efficiently removing and treating a fluorine-containing compound (PFC) gas.

1 is a process chart showing a PFC process in the present invention

2 is a structural diagram of a combustion chamber applied to the present invention;

Figure 3 is a structural diagram of the oxygen incubator used in the present invention

4 is a block diagram of the apparatus

5 is the flame temperature measurement test result

Figure 6 PFC removal rate experiment results

<Explanation of symbols for main parts of drawing>

11: oxygen incubator 12: PFC outlet

13: Premix 14: LNG or LPG fuel

15: combustion chamber 16: flue gas treatment device

17: controller

21: PFC inlet pipe 22: combustor flue gas outlet pipe

23: fuel, air mixer inlet tube 24: exterior

25: Inner Tube 26: Ignition Machine

27: internal flame burner 28: metal mesh

31: air compressor 32: membrane module

33: oxygen enrichment side outlet pipe 34: discharge pipe

51: oxygen incubator 52: fuel supply unit

54: premixing chamber 55: fuel, air mixer supply pipe

56: fuel, PFC mixer supply pipe 57: combustion chamber

59: exhaust gas treatment device 60: discharge pipe

111: air 131: fuel, air inlet tube

132: fuel, PFC injection tube

Hereinafter, described in detail by the accompanying drawings as follows.

1 is a block diagram of a PFC treatment system and a treatment process. First, an exhaust gas 121 containing PFC first passes through a filter 12 to remove a solid component, and then premixes a chamber through a tube. (13), where it is mixed with trace amounts of fuel 14, such as LNG or LPG, to produce a mixture of PFC and fuel. The air is sent to the oxygen incubator 11 through the air suction pipe 111, and the air containing the high concentration of oxygen, that is, the oxygen enriched air, is sent to the premixing chamber 13 to mix well with the fuel 13. The result is a mixture of fuel and air. The two mixed gases thus prepared are sent to the combustion chamber 15 through the fuel / air injection tube 131 and the fuel-PFC injection tube, respectively. In the combustion chamber, it is ignited with a fuel air mixer to form a hot flame, and the PFC-fuel mixture is divided into four tubes to be evenly injected into the combustion chamber at the top of the combustion chamber and sent to the combustion chamber. In the combustion chamber, the PFC is decomposed at a high temperature, exhaust gas composed of carbon dioxide (CO2), water vapor (H2O), hydrofluoric acid (HF), and the like is generated and sent to the exhaust gas treatment device 16. In the flue gas treatment system, the flue gas is first cooled, and then the harmful components in the flue gas are dissolved and treated in water. In this series of processes, the control of air and fuel, the monitoring and control of the flame temperature, etc. are handled via the control unit 17.

The structure of the system is shown in FIG. The air passing through the oxygen incubator 51 passes through the premixing chamber 54 to be reacted with the PFC in the combustion chamber 57, and after the treatment, the exhaust gas is harmless using water in the exhaust gas treating apparatus 59. It consists of a device.

Looking at the oxygen incubator in more detail through Figure 2 as follows. Air passes through the air compressor 31 and passes through the hollow fiber membrane-type membrane module 32, which is composed of a combination of small tubes with an empty pressure in the state of increasing pressure, to selectively pass oxygen to allow oxygen of about 23-25%. Oxygen-enriched air concentration is contained is sent to the outlet pipe 33, the air does not pass through the discharge pipe 34 is sent to the outside.

Looking at the configuration and operation of the combustion chamber through Figure 3 as follows. The PFC-fuel mixture is separated into four tubes and injected into the combustion chamber top through the tubes 21. The fuel-air mixer is separated into two tubes 23 and injected into the combustion chamber in a tangential direction above the combustion chamber side to form a flame with the igniter. The formed flame and the PFC gas is a spiral flame is formed along the inner wall of the exterior 24 of the combustion chamber, the flame descends from the top to the bottom, and the flame arriving at the bottom of the exterior enters the inner tube. In the inner tube, a metal mesh 28 is installed at the upper and lower ends to promote radiant heat transfer, and an inner flame burner is installed from the inner wall of the inner tube to the center to maintain a high temperature of the flame. During this process, the PFC gas is reacted for a long residence time while flowing together along the flow of the flame to be completely decomposed, and the exhaust gas after the reaction is sent out of the combustion chamber through the discharge pipe 22.

As a result of performing a preliminary experiment by fabricating a device according to the present invention, as shown in FIG. 5, when the oxygen enrichment concentration is 23%, 1210 ° C., and when the temperature is 25%, the flame temperature is increased to 1420 ° C. It was confirmed that a flame was formed at a temperature higher than possible to decompose.

As shown in FIG. 6, CF ₄ and C ₂ F ₆ in PFC gas were diluted in nitrogen gas at a concentration of 500 ppm to 3000 ppm, and the removal rate of PFC gas was measured. As a result, CF 4 was 95% at maximum, and C ₂ F _6. Confirms that the removal rate is up to 99%, demonstrating the possibility of the detoxification treatment of the PFC of the apparatus. As a result of the preliminary experiment as described above, it was confirmed that more than 90% of the PFC can be removed through the apparatus.

As described above, in the present invention, the oxygen-enriched air using the separator and the double-pipe spiral flame type combustor are used to detoxify the fluorine-containing compound and to purify the exhaust gas through the flue gas treatment device to be a global warming material. It is to remove and process PFC gas.

Claims (2)

In the method of combusting harmful gases containing fluorine-containing compounds (PFC), Method of producing fluorine-containing compounds by producing oxygen enriched air with oxygen enrichment membrane and premixing with fuel to burn this premix in combustion chamber In the system for the combustion treatment to remove the fluorine-containing compound, Oxygen-enriched separation feeder to produce high concentration oxygen-enriched air, A device for premixing fuel and air and fuel and PFC respectively to a combustion chamber, Combustion chamber which forms a swirling flame and consists of a double tube Internal combustion chamber which inserts metal mesh or honeycomb material to promote flame temperature and radiant heat, Fluorine-containing compound treatment system consisting of a combination of flue gas treatment devices for wet treatment of flue gas after combustion treatment of PFC