CN2633410Y

CN2633410Y - Full fluoride waste gas plasma processing device

Info

Publication number: CN2633410Y
Application number: CN 03207888
Authority: CN
Inventors: 郑石治; 蔡尤溪
Original assignee: Desiccant Technology Corp
Current assignee: Desiccant Technology Corp
Priority date: 2003-09-10
Filing date: 2003-09-10
Publication date: 2004-08-18
Anticipated expiration: 2013-09-10

Abstract

A full fluoride waste gas plasma processing device comprises a waste gas inlet, a plasma torch and a reaction chamber; wherein a sink is arranged under a plasma reactor and a sprayer component is arranged near an outlet of the reaction chamber and on the top of the sink; a wet scrubbing tower is arranged above the sink; a water pump connects the sink with the other sprayer component which is arranged on the upper part of the wet scrubbing tower. The waste gas is directed to make direct actions with the high temperature plasma torch, then processed in the reaction chamber and cooled down through the sprayer component, and redirected to a wet scrubbing tower for processing and discharged in the end, wherein the recycling water used in the wet scrubbing tower is supplied by a sink. In the demonstration test of the utility model, a removal rate of the destroy caused by C2F6 reaches as high as 99.9 percent, thereby the utility model has a high environmental protection price, moreover the utility model can process a plurality of full fluoride waste gases, destroy and decompose chemical bonds of such harmful waste gases as CF4, C2F6 and NF3 of which a removal rate reaches not less than 99 percent.

Description

Plasma treatment device for perfluorinated waste gas

Technical Field

The utility model relates to a waste gas treatment device, in particular to a perfluorinated compound waste gas plasma treatment device.

Background

Perfluorinated compounds are one of the greenhouse regulated gases. Jingdu protocol of climate Change outline convention of United nations in 1997In the book, countries regulate six main greenhouse gases (carbon dioxide CO)₂Methane CH₄Nitrous oxide N₂O, sulfur hexafluoride SF₆Hydrofluorocarbon HFCs and perfluorocompound PFCs, etc.). Among the six major regulated greenhouse gases, SF₆HFCs, PFCs, and the like are mainly artificial greenhouse gas components. Although HFCs and PFCs do not deplete the ozone layer, they are potent greenhouse gases with high Global Warming Potential (GWP) values₆The GWP of (A) is: 140-11700, 6500-9200 and 23900, can stay in the atmosphere for a long time, has a very long life span, and has an irreversible accumulation effect in the atmosphere. In recent years, CF has been widely used in semiconductor manufacturing processes (e.g., cleaning processes in dry etching chemical vapor deposition, etc.)₄、C₂F₆、NF₃Perfluorochemicals (PFC) are used as process gases, only a small portion of which is used, and the remaining majority (e.g., about 90% of the remainder of the CVD) is used as exhaust emissions, which are a significant source of greenhouse effect. Since countries in which the semiconductor industry is developed have common knowledge and agreements that will not regulate the emission of PFCs gases in the future, taiwan semiconductor industry will be constrained by such agreements. However, the manufacturing technology of semiconductor devices is becoming more sophisticated, and the amount of perfluoro compounds used is increasing with the progress of semiconductor manufacturing process, so that it is necessary to control and process the waste gas to avoid the environmental pollution, and to adopt a new PFCs waste gas treatment system to meet the more stringent waste gas emission standard in the future.

Known methods and apparatus for treating perfluorinated exhaust gases are shown in figures 1 and 2.

As shown in fig. 1, a well-known perfluorinated compound electric heating box treatment device is disclosed. The waste gas is introduced into the electric heating box 10, the perfluorinated compounds are decomposed at high temperature by heating through the heating wire 11, and finally discharged from the windmill 20 through a chimney 30, but the waste gas is heated by electric heat, so that on one hand, the waste gas consumes electric energy and is poor in energy efficiency, on the other hand, the maximum heating temperature can only reach about 1200 ℃, and a certain heating reaction time is needed, so that the air volume for treatment is generally small, and other solid matters are easy to remain in the electric heating box 10.

As shown in fig. 2, a well-known incineration disposal apparatus for a perfluorinated compound combustion furnace is disclosed. Typically, gas is used as fuel, the gas is introduced into a flame nozzle 41 and ignited to form a flame with energy density of 1-3 MJ/kg, the waste gas is introduced into a combustion furnace 40 for cracking and incineration, and the treated gas is sent to a chimney 60 by a windmill 50 and discharged to the atmosphere. The device has the advantages of larger waste gas treatment amount and higher temperature than those of electric heaters, but recently, semiconductor factories have been designed for safety, and the incineration treatment device of a gas combustion furnace is not adopted as the waste gas treatment device by the factory so as to avoid danger.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a perfluoride waste gas plasma processing apparatus can high-efficiently handle perfluoride waste gas.

In order to achieve the above object, the utility model discloses with the design principle that high energy density plasma pyrolysis and washing were removed the evil, provide a high efficiency perfluor compound waste gas plasma processing apparatus and contain:

a plasma reactor, which consists of a waste gas inlet, a plasma torch and a reaction chamber;

a water tank located below the plasma reactor, and a water sprayer set located at the outlet of the reaction chamber above the water tank;

a wet scrubber tower located above the water tank;

and a water pump is connected with the water tank and another water sprayer group at the upper end of the wet-type washing tower.

Introducing waste gas to directly act with high-temperature plasma torch, treating in reaction chamber, setting a water sprayer at outlet of reaction chamber, cooling waste gas, introducing into a wet scrubber, treating, and discharging.

The plasma torch is a non-transmission type direct current plasma torch which generates high-temperature plasma by supplying direct current power.

The perfluorinated compound waste gas plasma treatment device is characterized in that the inner layer material of the reaction chamber is a refractory heat-insulating material.

The perfluorinated waste gas plasma treatment device is characterized in that the water sprayer group consists of two or more groups of water sprayers.

The plasma treatment device for the perfluorinated compound waste gas is characterized in that a windmill is additionally arranged behind a wet-type washing tower of the device.

The plasma torch and the reaction chamber are vertically arranged, and the flame direction of the plasma torch is vertical to the gas flow direction of the waste gas passing through the plasma torch.

The utility model discloses an application scope contains the treatment of harmful waste gas such as perfluoride of semiconductor and other industrial manufacturing process, for example: c₂F₆、SiH4、CF₄、NF₃、CHF₃And the like. The basic working principle of the utility model is as follows: the DC plasma torch generates high-temperature (more than 10000 ℃) and high-energy density (10-80MJ/kg) plasma, pyrolyzes, atomizes and ionizes perfluorinated compounds in the exhaust gas, so that chemical bonds of the perfluorinated compounds are broken down and destroyed, and the perfluorinated compounds are combined with water or oxygen to form simple and easily-handled molecules or atoms such as hydrogen, carbon monoxide, carbon dioxide, hydrogen fluoride and the like, and the simple and easily-handled molecules or atoms are not combined into larger or more complex molecules, which cannot be achieved by a common traditional thermal combustion furnace. The reaction equation is illustrated as follows,

however, because the temperature of the waste gas after the plasma torch treatment is extremely high and hydrogen fluoride gas is generated, a water sprayer group is arranged at the outlet of the plasma reaction chamber to spray water mist, so that the gas is rapidly cooled and partof HF is dissolved, but the gas solubility is not high due to the influence of high temperature, after the waste gas is cooled by spraying water mist, it is introduced into a wet scrubber tower, in which the interior of said scrubber tower is filled with high-surface-area filler and equipped with water-sprayer group, the entrained solid particles, such as silicon-containing powder, can be washed and filtered, and the hydrogen fluoride is absorbed at the same time, when the product containing hydrogen fluoride is treated, the sprayed water mist can be added with alkali to neutralize the acidity of hydrogen fluoride, a wastewater treatment field is generally arranged, the fluorine-containing wastewater can be treated by the wastewater treatment field, therefore, the water storage of the water tank of the utility model can be discharged in batches or continuously discharged to a wastewater treatment plant.

Drawings

For a better understanding, reference is made to the following drawings which illustrate a preferred embodiment of the invention.

FIG. 1 illustrates a known perfluorinated electrothermal heater box treatment apparatus;

FIG. 2 shows a known incineration disposal unit for a perfluorinated compound combustion furnace;

FIG. 3 shows a high efficiency plasma treatment apparatus for perfluorinated compounds exhaust.

Detailed Description

Fig. 3 is a schematic diagram of a preferred embodiment of the plasma treatment device for high efficiency perfluorinated compounds exhaust gas according to the present invention, and the principle and operation thereof will be described below toclearly illustrate the feasibility and advantages of the present invention.

The utility model provides a high efficiency perfluor compound waste gas plasma processing apparatus with the design principle that high energy density plasma pyrolysis and washing were removed the evil, it contains a plasma torch, a reacting chamber, a sprinkler group, a basin, a wet scrubbing tower. Introducing waste gas to directly act with high-temperature plasma torch, treating in reaction chamber, setting a water sprayer at outlet of reaction chamber, cooling waste gas, introducing into a wet scrubber, treating, and discharging, wherein the water for circulation is supplied by a water tank.

The utility model discloses a function as follows: the plasma reactor 110 includes three parts, i.e., an exhaust gas inlet 111, a plasma torch 112, and a reaction chamber 113, wherein the interior of the reaction chamber is constructed by a refractory and heat-insulating material, and a high-temperature environment can be formed by heating the plasma torch. Perfluorinated exhaust gas enters the plasma reactor 110 through an exhaust gas inlet 111, and is ventilated with a very high temperature (10000 ℃) plasma beam of a plasma torch 112, the perfluorinated exhaust gas is instantaneously pyrolyzed, atomized or ionized in the plasma torch 112 and a reaction chamber 113, chemical bonds among perfluorinated components are broken down and destroyed, and molecules or atoms such as hydrogen, carbon monoxide, carbon dioxide, hydrogen fluoride and the like which are simple and easy to process are formed, and the perfluorinated exhaust gas does not have the opportunity to be combined into larger or more complex molecules which cannot be reached by a hot combustion furnace. However, since the temperature of the exhaust gas treated by the plasma reactor 110 is very high and hydrogen fluoride gas is generated, a water sprayer group 120 is installed at the outlet of thereaction chamber 113 of the plasma reactor 110, the water sprayer group 120 is provided with a water amount control valve 121 to control the water spraying amount so as to spray water mist from a water sprayer 122, so that the water absorbs heat to rapidly cool the exhaust gas and dissolve part of Hydrogen Fluoride (HF), but since the high temperature affects the solubility of the gas, the exhaust gas is introduced into a wet scrubber 150 to be filled with a filler with a high surface area after being spray-cooled, and a water sprayer group 151 is installed, a water source of the water sprayer group 151 is supplied by water pumped from a water pump 140 to a water tank 130, and a filter 141 may be installed in front of the water pump 140 to filter impurities and solids. While the waste gas passes through the wet scrubber 150, the entrained solids, such as silicon-containing powder, can be washed and filtered out, and the hydrogen fluoride can be absorbed therein, and when the hydrogen fluoride product is treated, the sprayed water mist can be added with alkaline solution to neutralize the hydrogen fluoride acidity. However, in the present situation, a wastewater treatment plant is provided in a scientific park, and usually fluorine-containing wastewater is treated by the wastewater treatment plant. Therefore, the water storage of the water tank of the utility model can be discharged in batches or continuously discharged to a wastewater treatment plant. When the static pressure of the air flow provided by the waste gas source is insufficient, the rear end of the wet scrubber tower 150 of the present invention can be provided with a windmill 160 to compensate the static pressure, so as to smoothly discharge the designed air flow value.

The utility model discloses owing to adopt the plasma reactor 110 than publicly known processing method high like the energy density of combustion method, consequently, the schizolysis efficiency of perfluor thing is higher, and the efficiency superiority promotes by a wide margin. The device of the utility model demonstrates and processes C₂F₆The destruction removal rate of the catalyst can reach 99.9 percent, and the catalyst has environmental protection value, and simultaneously can be proved to simultaneously treat various perfluorinated compound waste gases and remove CF₄、C₂F₆And NF₃The chemical bonds of harmful waste gas are destroyed and decomposed, and the removal efficiency can reach more than 99 percent.

The utility model discloses plasma torch is the non-transmission type direct current plasma torch that adopts direct current power supply to produce high temperature plasma during the experiment. Evaluating the existing semiconductor waste gas treatment equipment, namely, the dry type washing tower after the manufacture process of Metal Etch is used for treating HCl and BCl₃And CCl₄The treatment efficiency of (2) can reach 99%, but the treatment effect on fluorine-containing compounds is poor, especially on PFCs (for example: CF)₄) Almost no treatment effect, and a controlled pyrolytic oxidizer (CDO) treatment facility for NH₃、SiF₄Has an excellent processing efficiency of more than 99% for SiH₄、N₂O、NF₃The treatment efficiency of the gases is below 30 percent, so the utility model also has the advantages of the utility model.

Claims

1. A perfluorinated exhaust plasma treatment device, comprising:

a wet scrubber tower located above the water tank;

a water pump is connected to the water tank and another water sprayer group at the upper end of the wet scrubber tower.

2. The plasma treatment apparatus for perfluorinated exhaust gases according to claim 1, wherein the plasma torch is a non-transmission type direct current plasma torch generating high temperature plasma by direct current power supply.

3. The plasma treatment device of perfluorinated exhaust gases according to claim 1 wherein the inner layer material of the reaction chamber is a refractory heat-insulating material.

4. The plasma treatment apparatus for perfluorinated exhaust gas according to claim 1, wherein the water injector group comprises two or more groups of water injectors.

5. The plasma treatment apparatus for perfluoro-compound exhaust gas according to claim 1, wherein a windmill is added after the wet scrubber of the apparatus.

6. The plasma treatment apparatus for perfluorinated exhaust gases according to claim 1, wherein the plasma torch and the reaction chamber are arranged in an upright manner, and the flame direction of the plasma torch and the flow direction of the exhaust gas passing through the plasma torch are arranged to be perpendicular to each other.