JP2004223302A - Exhaust gas treatment method and treatment apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas treatment method capable of efficiently treating a fluorine-containing compound and CO at the same time, reduced in running cost, low in the load to an apparatus material, capable of reducing an apparatus cost and discharging no harmful gas. <P>SOLUTION: At least one of a powder component, a water soluble component and a hydrolizable component contained in an exhaust gas containing at least either of the fluorine-containing compound or CO is removed and, after O<SB>2</SB>and water (H<SB>2</SB>O) are added to the exhaust gas, the exhaust gas containing O<SB>2</SB>and water is heated to decompose or oxidize at least one of the fluorine-containing compound and CO. Subsequently, the acidic gas, which is produced when the fluorine-containing compound is decomposed, is removed from the exhaust gas subjected to decomposition or oxidation treatment. The heating of the exhaust gas containing O<SB>2</SB>and water is preferably performed at 700-900°C. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３７】
流入条件として、ＳｉＦ_４：６０ｍＬ／ｍｉｎ、ＣＨＦ_３：１８０ｍＬ／ｍｉｎ、Ｃ_４Ｆ_８：６０ｍＬ／ｍｉｎ、Ｃ_４Ｆ_６：１０ｍＬ／ｍｉｎ、ＣＯ：１２００ｍＬ／ｍｉｎ、Ｃ_５Ｆ_８：１０ｍＬ／ｍｉｎ、ＮＦ_３：１２０ｍＬ／ｍｉｎ 、ＳＦ_６：１２０ ｍＬ／ｍｉｎ、ＣＦ_４：４５０ｍＬ／ｍｉｎ、の処理対象となるガスをＮ_２ガス：１２０Ｌ／ｍｉｎ中に混合して投入している。そして、酸化用Ｏ_２源として空気３．０Ｌ／ｍｉｎを加熱酸化部に導入し、同様に酸化・分解用として純水５ｍＬ／ｍｉｎを加熱酸化部に導入している。入口、前処理部出口、加熱酸化部出口、後処理部出口におけるそれぞれのガス成分の濃度は表１に示すとおりである。
【００３８】
上記表１に示す試験結果から、前処理部によりＳｉＦ_４、ＨＦが検出されず、前処理部で酸性ガスが良好に処理されていることが判る。そして、加熱酸化部でＣＯ、Ｃ_４Ｆ_８、Ｃ_５Ｆ_８、Ｃ_４Ｆ_６、ＣＨＦ_３、ＮＦ_３が検出されず、加熱酸化部でこれらのガス成分が良好に処理されていることが判る。さらに、加熱酸化部出口に存在していたＣＦ_４、ＳＦ_６が後処理部出口で検出されず、触媒反応部および後処理部で良好に処理されていることが判る。また、後処理部出口においてＨＦが検出されず、触媒反応部でＨＦが発生しても後処理部で良好に処理されていることが判る。
【００３９】
図４は本発明の排ガス処理装置の外観を示し、この装置は前処理部、加熱酸化分解処理部、触媒反応部、後処理部をすべて搭載することが可能で、ＰＦＣ，ＣＯとともに酸性ガスやＮＨ_３などの水溶性成分、加水分解成分や粉体成分を低コストで高効率に除去することが可能である。従って、この装置は、半導体製造装置等から排出される反応性成分および有害成分の高い除去能力を備えている。また、この装置は、コンパクトな構造であり、据付面積が小さく、またメンテナンススペースも小さくできる。更に、例えばサーマルＮＯｘ等を排出することなく、基本的コンセプトとして万全の安全性を確立したものであり、機器として優れた安全性を有する。
なお、本実施例においては、前処理部前処理部、加熱酸化分解処理部、触媒反応部、後処理部をすべて搭載しているが、前処理部および後処理部は装置外に別途設置するようにしても良い。さらに、工場内にて複数の排ガス処理装置から出る排ガス中の酸性ガスを１ヶ所にて一括処理するような後処理部を含むシステムにしても良い。
【００４０】
なお、本発明の排ガスの処理方法および装置は、上述の図示例にのみ限定されるものではなく、本発明の要旨を逸脱しない範囲において種々変更を加えうることは勿論である。
【００４１】
【発明の効果】
上述したように、本発明によれば、半導体製造装置等から排出されるフッ素含有化合物及びＣＯを含む排ガスを効率よく経済的に無害化処理することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態の排ガス処理装置を示すブロック図である。
【図２】本発明の第２の実施形態の排ガス処理装置を示すブロック図である。
【図３】本発明の第３の実施形態の排ガス処理装置を示すブロック図である。
【図４】図１乃至図３の排ガス処理装置の外観図である。
【符号の説明】
１ 前処理部（前処理用水スプレー塔）
２ 加熱酸化分解処理部（加熱酸化分解処理槽）
３ 触媒反応分解処理部（触媒反応槽）
４ 後処理部（後処理用水スプレー塔）
５，２１ 空気配管
６ 水配管
７，２３ 水清浄器
８ 水気化器
９，１０，１９ セラミック電気管状路
１３ ガス処理槽
１４ 前処理部（前処理用ファンスクラバ）
１５ 送水ポンプ
１５ａ 循環タンク
１６ 加熱酸化部
１７ 触媒反応部
１８ 後処理部
２０ 保温材
２５ 水気化配管
２６，２７ ミストセパレータ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for treating exhaust gas, and in particular, a fluorine-containing compound discharged in a step of dry cleaning an inner surface of a semiconductor manufacturing apparatus in a semiconductor manufacturing process, a step of etching various film formation such as an oxide film, and the like The present invention relates to a method and apparatus for efficiently detoxifying exhaust gas containing carbon monoxide gas (hereinafter referred to as CO).
[0002]
[Prior art]
Fluorohydrocarbons such as CHF ₃ , CF ₄ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₈ , C ₅ F ₈ , C ₄ F ₆ , Fluorine-containing compounds such as perfluoro compounds (hereinafter referred to as “PFC”) such as SF ₆ and NF ₃ are used. In addition, CO, NH ₃ and O ₂ may be used in a semiconductor manufacturing apparatus. In the exhaust gas discharged from the semiconductor manufacturing apparatus using these fluorine-containing compounds and CO or NH ₃ , CO, NH ₃ , SiF ₄ , F ₂ , COF ₂ , C ₅ F ₈ , C ₄ F ₆ , NF ₃ are contained. And fluorine-containing compounds that are not harmful but have a global warming effect. Therefore, when exhaust gas discharged from semiconductor manufacturing equipment using fluorine-containing compounds or CO is discharged into the environment, detoxification of harmful gases contained in the exhaust gas and decomposition treatment of global warming gas are required. .
[0003]
As a conventional harmful gas treatment method such as SiF ₄ , F ₂ , COF ₂ , C ₅ F ₈ , C ₄ F ₆ , NH _{3 in} the exhaust gas, a harmful component is adsorbed using an adsorbent such as synthetic zeolite. There is a way. However, there is a problem that CO and PFC cannot be removed. In addition, periodic replacement of the adsorbent is necessary, and there is a problem that running cost increases.
There are treatment methods for water-soluble gases such as SiF ₄ , F ₂ , and NH ₃ and hydrolyzable gases using a wet exhaust gas treatment device (water washing treatment). However, there is a problem that gases other than water-soluble such as CO and PFC cannot be removed.
[0004]
Further, as a conventional method for treating CO in exhaust gas, there is a method of oxidizing CO to CO ₂ using an oxidation catalyst and O ₂ . However, there is a problem that the PFC cannot be decomposed and removed. In addition, when an acidic gas such as SiF ₄ or F ₂ or PFC comes into contact with the oxidation catalyst, there is a problem that the oxidation catalyst is poisoned, the CO oxidation ability is lowered, and the oxidation catalyst needs to be periodically replaced.
[0005]
As a conventional method for simultaneously treating harmful gas and CO in exhaust gas, a combination of the above-described adsorption treatment, water washing treatment and oxidation treatment is possible. However, since there is a periodic replacement of the treatment agent, the running cost becomes high. There is also a problem that PFC cannot be removed.
[0006]
Removal methods using various PFC decomposition catalysts have been proposed (see Patent Documents 1 and 2). However, when the catalyst deteriorates, harmful components such as CO, C ₅ F ₈ , and C ₄ F ₆ may flow out immediately. Moreover, although the processing method by a combustion system is proposed, NOx and CO may generate | occur | produce as a by-product gas by combustion conditions. Further, there is a problem that fuel such as H ₂ , city gas, and propane gas is required, equipment for supplying the fuel is required, and operation management becomes complicated. In addition, although a method of decomposing by heat oxidative decomposition has been proposed, in order to decompose a hardly decomposable PFC such as CF ₄ , a high temperature of 1400 ° C. or higher is required, and the load on materials and heaters is extremely high. There is a problem of being big.
[0007]
In addition, there has been proposed a method in which NH ₃ or a lower saturated hydrocarbon gas or a lower unsaturated hydrocarbon gas is added to perform thermal oxidative decomposition without free O ₂ (see Patent Documents 3, 4, and 5). No method has been proposed for heat oxidation decomposition in the presence of O ₂ . Further, a method for decomposing PFC by plasma in the presence of water (H ₂ O) has been proposed, but when decomposing PFC, harmful gases such as CO and HF are generated, and thermal NOx is generated. Therefore, an exhaust gas treatment apparatus for treating these is separately required.
[0008]
[Patent Document 1]
Japanese Patent No. 3217034 [Patent Document 2]
Japanese Patent No. 3237651 [Patent Document 3]
JP-A-9-85045 [Patent Document 4]
Japanese Patent Laid-Open No. 11-333247 [Patent Document 5]
JP-A-11-162335
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned circumstances, can treat fluorine-containing compounds and CO simultaneously and efficiently, has a low running cost, has a low load on apparatus materials, and can reduce apparatus costs. An object of the present invention is to provide an exhaust gas treatment method and a treatment apparatus that do not emit harmful gases.
[0010]
[Means for Solving the Problems]
The exhaust gas treatment of the present invention removes at least one of a powder component, a water-soluble component and a hydrolyzable component contained in the exhaust gas containing at least one of a fluorine-containing compound and CO, and then removes O ₂ and water (H ₂ O) is added and heated to decompose or oxidize at least one of the fluorine-containing compound and CO, and then the acidic gas generated when the fluorine-containing compound is decomposed from the decomposed or oxidized exhaust gas It is characterized by carrying out the removal. Here, it is preferable to perform the said heating at the temperature of 700-900 degreeC.
[0011]
According to the present invention, it is possible to remove harmful gases such as SiF ₄ and F _{2 to} a concentration equal to or lower than an allowable value (TLV-TWA value) by adsorption treatment or gas-liquid contact treatment. Further, it is possible to oxidize CO to CO ₂ without using a CO oxidation catalyst, preferably by heat oxidation treatment at 700 to 900 ° C., and to treat it at a concentration below an allowable value (TLV-TWA value). In addition, harmful PFCs such as C ₄ F ₆ , C ₅ F _8, and NF ₃ can be completely decomposed to a concentration below an allowable value (TLV-TWA value) by heat treatment. And acidic gas, such as HF which arises when decomposing | disassembling a fluorine-containing compound by heat | fever oxidative decomposition process, can be removed by a subsequent adsorption process or a gas-liquid contact process. Therefore, for example, exhaust gas components that are harmful to the human body can be rendered harmless without using heat oxidative decomposition at a high temperature of 1000 ° C. or higher and without using a catalyst. In the heat treatment at 700 to 900 ° C., for example, a hardly decomposable PFC such as CF ₄ is difficult to decompose. However, these components are problematic from the viewpoint of global warming and the like, but are not harmful to the human body, and according to the exhaust gas treatment method, all the gas components that are harmful to the human body are allowable values. The following can be processed.
[0012]
It is also possible to completely decompose hardly decomposable PFC such as CF ₄ at a relatively low temperature of 600 to 900 ° C. by catalytic reaction. Therefore, for example, by using a catalytic reaction in combination after the heat oxidative decomposition treatment, these gas components that require treatment from the viewpoint of global warming can be completely decomposed and removed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0014]
FIG. 1 shows an exhaust gas treatment apparatus according to a first embodiment of the present invention. This exhaust gas treatment apparatus includes a pretreatment unit 1 that removes a powder component, a water-soluble component, or a hydrolyzable component contained in an exhaust gas containing a fluorine-containing compound and CO, and a heat oxidative decomposition treatment of the exhaust gas after the pretreatment. A heating oxidative decomposition processing unit 2 to be performed and a post-processing unit 4 to perform a post-processing of an acidic gas such as HF generated by the above-mentioned thermal oxidative decomposition processing are provided.
[0015]
As the pretreatment unit 1, for example, a pretreatment water spray tower is used for gas-liquid contact. The spray tower 1 is supplied with tap water or industrial water, and is sprayed with water spray. Exhaust gas containing fluorine-containing compound and CO flows from the lower part to the upper part of the water spray tower 1 and comes into contact with water sprinkled from the water spray, thereby causing powder components, water-soluble components, and hydrolyzable components in the exhaust gas. Remove. In addition to the water spray tower 1, a similar effect can be obtained even if an adsorption tank filled with an adsorbent such as a zeolite / activated carbon is installed in the pretreatment section.
[0016]
As an apparatus used as the pretreatment unit, an appropriate apparatus can be selected depending on the components of exhaust gas to be treated, the state of mixing powder, and the state of factory equipment. Adsorption with an adsorbent is suitable when there is no wastewater treatment facility because water is not used. In addition, when a special management substance such as As (arsenic) or Pb (lead) is contained in the exhaust gas, the washing process is not preferable because these components are mixed in the waste water, and therefore the adsorption process is suitable. Further, the fan scrubber can obtain a high removal rate with a low amount of water. In addition, the powder collection performance is also excellent. Further, since the water spray tower has a simple structure, it is necessary to increase the amount of water in order to obtain a high removal performance, but the apparatus becomes inexpensive. Further, the aeration and stirring tank can be adjusted in pH by introducing a neutralizing solution into the stirring tank, and a high removal rate can be obtained even for components that are difficult to remove by washing with water.
[0017]
In the pretreatment section, the powder component, water-soluble component, or hydrolyzable component contained in the exhaust gas is removed with water or an adsorbent as described above. For example, acidic gases such as SiF ₄ and F ₂ are removed by the pretreatment unit.
[0018]
The exhaust gas that has passed through the pretreatment section is decomposed in the heat oxidation decomposition treatment tank 2. The decomposition treatment is performed in the heat oxidation decomposition treatment tank 2 and an air pipe 5 is connected to supply O ₂ necessary for the reaction. A water pipe 6 necessary for the reaction is also connected. The city water or industrial water is purified to the equivalent of distilled water by the water purifier 7 connected to the pipe 6 before being introduced into the heating oxidative decomposition treatment tank 2. Then, it is vaporized by the water vaporizer 8 and supplied to the heating oxidative decomposition treatment tank 2. Alternatively, the water necessary for the reaction may be sprayed as it is on the heat oxidation decomposition treatment tank without spraying by the water vaporizer 8 as it is. Then, the sprayed water is heated and vaporized in a heating oxidative decomposition treatment tank. A ceramic electric tubular furnace 9 is attached to the heating oxidative decomposition treatment tank 2 as a heating means, and the exhaust gas temperature in which exhaust gas, O ₂ and water (H ₂ O) are mixed is heated to 700 to 900 ° C. As a result, in the heat oxidative decomposition treatment tank 2, the oxidation treatment of CO and the decomposition treatment of PFC, fluorinated hydrocarbon and NF ₃ having 4 or more carbon atoms are performed by the following reaction formula. Therefore, all the gas components harmful to the human body contained in the exhaust gas can be oxidized or decomposed.
[0019]
2CO + O ₂ → 2CO ₂
CO + H ₂ O → CO ₂ + H ₂
2H ₂ + O ₂ → 2H ₂ O
_{C 5 F 8 + 4H 2 O} + 3O 2 → 5CO 2 + 8HF
_{C 4 F 8 + 4H 2 O} + 2O 2 → 4CO 2 + 8HF
2C ₄ F ₆ + 6H ₂ 0 + 5O ₂ → 8CO ₂ + 12HF
2CHF ₃ + 2H ₂ O + O ₂ → 3CO ₂ + 8HF
2NF ₃ + 3H ₂ O → NO + NO ₂ + 6HF
[0020]
In the oxidation treatment, O ₂ may be supplied from any O ₂ source such as air in the atmosphere, O ₂ enriched air, pure O _2, or a peroxide. Note that the temperature of 700 to 900 ° C. is used for the oxidation and decomposition treatment, and the gas component can be oxidized and decomposed at this temperature, and in the high temperature range of 1000 ° C. or higher, the thermal generated from N ₂ or the like in the air. This is because there is a problem that the amount of NO _X generated increases. Moreover, it is because an economical thing can be used for a fireproof material etc. which are required for a tank by setting it as 900 degrees C or less.
[0021]
The post-processing unit 4 performs post-processing of an acidic gas such as HF that is generated when the fluorine-containing compound is decomposed. In this embodiment, it is a post-treatment water spray tower 4. This is supplied with tap water or industrial water and is sprayed with water spray. The exhaust gas flows from the lower part to the upper part of the water spray tower 4 and comes into contact with the water sprayed from the water spray, thereby removing HF generated when the PFC is decomposed in the heated oxidative decomposition treatment tank 2. In addition to the water spray tower 4, a post scrubber, an aeration and stirring tank, and an adsorption tank filled with an adsorbent such as zeolite / activated carbon can be used to obtain the same effect.
[0022]
FIG. 2 shows an exhaust gas treatment apparatus according to a second embodiment of the present invention. In this apparatus, the exhaust gas that has been subjected to the thermal oxidative decomposition process is subsequently decomposed by a catalyst in the catalytic reaction tank 3 that is a catalytic reaction unit. The configuration other than the provision of the catalyst reaction tank 3 is the same as the configuration of the exhaust gas treatment apparatus shown in FIG.
[0023]
The catalytic reaction tank 3 is filled with a PFC decomposition catalyst, and the exhaust gas flows from the upper layer of the catalyst layer toward the lower layer. Moreover, the ceramic reaction tubular furnace 10 is attached to the catalyst reaction tank 3 as a heating means, and the temperature of the catalyst reaction tank 3 is heated to 600 to 900 ° C. Thus the catalytic reaction section occurs following reactions by contacting the PFC and SF ₆ and the catalyst of 3 or less carbon atoms, decomposition treatment of PFC and SF ₆ are performed. Note that O ₂ and water (H ₂ O) contributing to the decomposition reaction are introduced in the upstream heat oxidation decomposition treatment tank 2. As the catalyst, a fluorine-containing compound decomposition catalyst such as a catalyst in which tungsten oxide is supported on γ-alumina or alumina-zirconium composite oxide is used. Thereby, the decomposition process of the hardly decomposable PFC and SF ₆ which could not be processed in the heating oxidative decomposition treatment tank 2 can be performed. Therefore, by adding the decomposition treatment by the catalytic reaction, it is considered that there is no direct influence on the human body, but exhaust gas components that are considered to have an adverse effect on global warming and the like can be completely removed.
[0024]
CF ₄ + 2H ₂ O → CO ₂ + 4HF
2C ₂ F ₆ + 6H ₂ O + O ₂ → 4CO ₂ + 12HF
C ₃ F ₈ + 4H ₂ O + O ₂ → 3CO ₂ + 8HF
2SF ₆ + 3H ₂ O + O ₂ → SO ₂ + SO ₃ + 6HF
[0025]
FIG. 3 shows an exhaust gas treatment apparatus according to a third embodiment of the present invention. This exhaust gas treatment apparatus includes a gas treatment tank 13 in which a heat oxidative decomposition treatment unit, a catalyst reaction unit, and a post-treatment unit are integrated. In addition, a fan scrubber 14 is installed in the pretreatment unit. The cleaning water is supplied to the fan scrubber 14 from the water pump 15, and the cleaning water and the exhaust gas come into contact with the rotation of the fan in the fan scrubber 14 to remove the powder component, water-soluble component, and hydrolysis component in the exhaust gas. .
[0026]
A gas treatment tank 13 corresponds to a heat oxidative decomposition treatment section, a catalyst reaction section, and a post-treatment section, and is provided with a heat oxidative decomposition section 16, a catalyst reaction section 17, and a post-treatment section 18 in the order in which exhaust gas passes. By making the heating oxidative decomposition unit 16, the catalytic reaction unit 17, and the post-processing unit 18 into an integral structure, the apparatus is downsized. Further, by integrating, the exhaust gas heated to 700 to 900 ° C. by the ceramic electric tubular furnace 19 in the heating oxidative decomposition unit 16 can be introduced into the catalyst reaction unit 17 without lowering the temperature. Therefore, it is not necessary to provide heating means such as a heater in the catalyst reaction unit 17, and it is only necessary to install the heat insulating material 20 on the outer periphery of the catalyst reaction unit 17.
[0027]
O ₂ required for the heat oxidative decomposition process and the catalytic reaction process is supplied from an air pipe 21 connected to the upper part of the gas processing tank 13. Further, water (H ₂ O) is purified to be equivalent to distilled water by the water purifier 23 and then introduced into the gas treatment tank 13. After that, when passing through the water vaporization pipe 25 installed on the outer wall of the ceramic electric tubular furnace 19 inside the gas treatment tank 13, the gas treatment tank is heated and vaporized by heat exchange with the exhaust heat of the ceramic electric tubular furnace 19. 13 is introduced into the heat oxidative decomposition processing unit 16 provided at the upper part of 13. A lower portion of the gas treatment tank 13 is provided with a post-treatment unit having a water spray 18, and cleaning water is supplied to the water spray 18 from a water supply pump 15.
[0028]
The exhaust gas to be treated passes through the pretreatment fan scrubber 14, then passes through the mist separator 26, and is introduced into the gas treatment tank 13. Further, the exhaust gas from which HF has been removed by the post-processing unit 18 passes through the mist separator 27 and is then exhausted as a harmless treated gas.
[0029]
Water (H ₂ O) is required for the CO oxidation reaction and PFC decomposition, and this water (H ₂ O) is vaporized and introduced into the exhaust gas treatment system. If Si or Ca is contained in the water, Si or Ca is deposited (scale is generated) when water (H ₂ O) is vaporized, and there is a possibility that clogging occurs in the apparatus. Further, Cl and the like may cause deterioration of the catalyst. Therefore, the supplied water (H ₂ O) needs to be clean water such as pure water or distilled water. In order to supply pure water or distilled water to the equipment, it is necessary to construct an independent dedicated pipe. Furthermore, a separate pure water production equipment or distilled water production equipment is required, which increases the cost burden on the equipment. . By providing the apparatus with a water purifier that purifies water, the water supplied to the apparatus may be tap water or industrial water, and the costs related to equipment such as piping can be reduced.
[0030]
Next, the exhaust gas treatment method of the present invention will be described.
The powder component, water-soluble component, or hydrolyzable component contained in the exhaust gas containing the fluorine-containing compound and CO is removed by pretreatment. As a pretreatment part that removes the powder component, water-soluble component or hydrolyzable component contained in the exhaust gas, any of an adsorption treatment tank, a fan scrubber, a water spray tower, an aeration stirring tank, etc. that performs an adsorption treatment with an adsorbent Is used.
[0031]
The exhaust gas containing the fluorine-containing compound and CO after removing the powder component, water-soluble component or hydrolyzable component by the pretreatment is brought into contact with O ₂ and water (H ₂ O) at a temperature of 700 to 900 ° C. In this way, CO is oxidized to CO ₂ and a fluorine-containing compound having 4 or more carbon atoms is decomposed. The heat oxidative decomposition treatment includes a hollow interior in which the exhaust gas can be vented, a heating means capable of heating the gas temperature in the hollow to 700 to 900 ° C., a gas inlet, an O ₂ inlet, and water (H _2). O) It is carried out in a heat oxidative decomposition treatment section provided with an inlet.
It is preferable to provide a contact assisting means for increasing the contact efficiency between the exhaust gas, O ₂ and water (H ₂ O) and increasing the heating efficiency. The exhaust gas is turbulent by the contact assisting means to increase the contact efficiency between the exhaust gas and O ₂ , water (H ₂ O), and the contact assisting means itself receives heat generated from the heater by radiation and becomes a high temperature. The heat transfer area becomes larger and the heating efficiency can be increased. As a result, the heat oxidative decomposition treatment unit can be miniaturized and the heater capacity can be kept low.
[0032]
Finally, the acidic gas (HF) generated when the fluorine-containing compound is decomposed in the heating oxidative decomposition processing section is removed. The removal of HF is performed using an adsorption treatment tank, a fan scrubber, a water spray, an aeration stirring tank, or the like that performs an adsorption treatment with an adsorbent as a post-processing section. This completes the processing of all gas components that are harmful to the human body in the exhaust gas.
[0033]
Furthermore, in order to remove a gas component which is a problem from the viewpoint of global warming, a decomposition treatment with a catalyst is performed after the heat oxidative decomposition treatment. That is, the fluorine-containing compound decomposition catalyst, O ₂ and water (H ₂ O) are brought into contact with each other at a temperature of 600 to 900 ° C. in the catalytic reaction section to decompose the fluorine-containing compound having 3 or less carbon atoms and SF _6. Can do. In the catalytic reaction section, the decomposition catalyst for the fluorine-containing compound can be filled, and the heating means for heating the catalyst layer temperature to 600 to 900 ° C. or the gas heated to 700 to 900 ° C. in the heating oxidative decomposition processing section in the previous stage is 600. A heat retaining means for maintaining the temperature at ˜900 ° C. is provided.
[0034]
It is also provided with a pure water generator or distillation apparatus or filter arrangement for water used for the exhaust gas treatment (H 2 _O) clean. It is preferable to provide a mechanism for vaporizing water (H ₂ O) supplied as a liquid by exchanging heat with exhaust heat from the heat oxidation decomposition treatment unit or the catalytic reaction unit. Thus, without requiring a special heat source for vaporizing water (H 2 _O) to utilize the exhaust heat.
[0035]
Moreover, it is preferable to provide a ceramic filler on the downstream side of the catalyst layer. When a water spray is used for the post-processing unit and the catalyst reaction unit and the post-processing unit are integrated, the provision of a filler prevents water from the water spray from reaching the catalyst layer and causes catalyst deterioration. Can be prevented. In addition, since water is retained in the gap between the packings, the contact efficiency between HF and water generated during PFC decomposition is increased, the HF removal efficiency is increased, and the exhaust gas cooling effect is also improved.
[0036]
Next, the test result of the exhaust gas treatment performed by a test device equivalent to the exhaust gas treatment device shown in FIG. 3 will be described. N ₂ gas mixed with various kinds of gas to be treated is introduced into the test apparatus, and the gas component concentration (ppm) of each part is measured.
[Table 1]

[0037]
As inflow conditions, SiF ₄ : 60 mL / min, CHF ₃ : 180 mL / min, C ₄ F ₈ : 60 mL / min, C ₄ F ₆ : 10 mL / min, CO: 1200 mL / min, C ₅ F ₈ : 10 mL / min , NF ₃ : 120 mL / min, SF ₆ : 120 mL / min, CF ₄ : 450 mL / min, a gas to be treated is mixed and introduced into N ₂ gas: 120 L / min. Then, 3.0 L / min of air as an O ₂ source for oxidation is introduced into the heating oxidation section, and similarly 5 mL / min of pure water is introduced into the heating oxidation section for oxidation and decomposition. Table 1 shows the concentration of each gas component at the inlet, the pretreatment section outlet, the heating oxidation section outlet, and the posttreatment section outlet.
[0038]
From the test results shown in Table 1, it can be seen that SiF ₄ and HF are not detected by the pretreatment unit, and that the acid gas is well treated in the pretreatment unit. Then, _CO in thermal oxidation _{unit, C 4 F 8, C 5} F 8, C 4 F 6, CHF 3, NF 3 is not detected, that these gas components are well treated with thermal oxidation unit I understand. Further, it can be seen that CF ₄ and SF ₆ present at the heating oxidation section outlet are not detected at the post-processing section outlet, and are well processed at the catalytic reaction section and the post-processing section. In addition, it can be seen that HF is not detected at the outlet of the post-processing section, and even if HF is generated in the catalytic reaction section, the post-processing section is well processed.
[0039]
FIG. 4 shows the external appearance of the exhaust gas treatment apparatus of the present invention. This apparatus can be equipped with a pretreatment part, a heat oxidation decomposition treatment part, a catalytic reaction part, and a posttreatment part. It is possible to remove water-soluble components such as NH ₃ , hydrolysis components and powder components with low cost and high efficiency. Therefore, this apparatus has a high removal capability of reactive components and harmful components discharged from a semiconductor manufacturing apparatus or the like. In addition, this apparatus has a compact structure, requires a small installation area, and can reduce a maintenance space. Furthermore, for example, the safety is established as a basic concept without discharging thermal NOx or the like, and has excellent safety as a device.
In this embodiment, the pre-processing unit pre-processing unit, the thermal oxidative decomposition processing unit, the catalytic reaction unit, and the post-processing unit are all mounted, but the pre-processing unit and the post-processing unit are separately installed outside the apparatus. You may do it. Furthermore, a system including a post-processing unit that collectively processes acidic gas in exhaust gas from a plurality of exhaust gas processing apparatuses in a factory may be used.
[0040]
It should be noted that the exhaust gas treatment method and apparatus of the present invention are not limited to the illustrated examples described above, and it goes without saying that various changes can be made without departing from the scope of the present invention.
[0041]
【The invention's effect】
As described above, according to the present invention, it is possible to efficiently and economically detoxify the exhaust gas containing a fluorine-containing compound and CO discharged from a semiconductor manufacturing apparatus or the like.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an exhaust gas treatment apparatus according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing an exhaust gas treatment apparatus according to a second embodiment of the present invention.
FIG. 3 is a block diagram showing an exhaust gas treatment apparatus according to a third embodiment of the present invention.
4 is an external view of the exhaust gas treatment apparatus of FIGS. 1 to 3. FIG.
[Explanation of symbols]
1 Pretreatment section (Pretreatment water spray tower)
2 Heating oxidative decomposition treatment section (heated oxidative decomposition treatment tank)
3 Catalytic reaction decomposition treatment section (catalytic reaction tank)
4 Post-processing section (post-treatment water spray tower)
5, 21 Air piping 6 Water piping 7, 23 Water purifier 8 Water vaporizer 9, 10, 19 Ceramic electric tubular passage 13 Gas treatment tank 14 Pretreatment section (fan scrubber for pretreatment)
15 Water Pump 15a Circulation Tank 16 Heating Oxidation Unit 17 Catalytic Reaction Unit 18 Post-Processing Unit 20 Heat Insulating Material 25 Water Vaporization Pipe 26, 27 Mist Separator

Claims (8)

Removing at least one of the powder component, the water-soluble component and the hydrolyzable component contained in the exhaust gas containing at least one of the fluorine-containing compound and CO, and then adding O ₂ and water (H ₂ O) Heating decomposes or oxidizes at least one of the fluorine-containing compound and CO, and then removes the acidic gas generated when the fluorine-containing compound is decomposed from the decomposed or oxidized exhaust gas. An exhaust gas treatment method. The exhaust gas treatment method according to claim 1, wherein in addition to the treatment, a decomposition treatment is further performed by a catalytic reaction. The exhaust gas treatment method according to claim 1, wherein at least one of the powder component, the water-soluble component, and the hydrolyzable component is removed by adsorption treatment with an adsorbent or gas-liquid contact treatment. The exhaust gas treatment method according to claim 1, wherein the acid gas is removed by adsorption treatment with an adsorbent or gas-liquid contact treatment. The exhaust gas treatment method according to claim 1, wherein the heating is performed at a temperature of 700 to 900 ° C. By adding O ₂ and water (H ₂ O) to an exhaust gas containing at least one of a fluorine-containing compound and CO and heating to 700 to 900 ° C., CO, a fluorine-containing compound having 4 or more carbon atoms, fluoride An exhaust gas treatment method comprising detoxifying at least one of hydrocarbon and NF ₃ . A processing section for removing at least one of a powder component, a water-soluble component, and a hydrolyzable component contained in an exhaust gas containing at least one of a fluorine-containing compound and CO, and heating of at least one of the fluorine-containing compound and CO A heat oxidative decomposition treatment unit that performs oxidative decomposition treatment to render it harmless, a supply unit that supplies O ₂ and water (H ₂ O) to the heat oxidative decomposition treatment unit, and an acidic gas in the exhaust gas after the oxidative decomposition treatment An exhaust gas treatment apparatus comprising a removal unit for removal. 8. The exhaust gas processing apparatus according to claim 7, further comprising a catalytic reaction decomposition processing section for performing a decomposition process by a catalytic reaction.

Images