JP2005185897A - Method for treating sulfur hexafluoride gas - Google Patents
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- JP2005185897A JP2005185897A JP2003427881A JP2003427881A JP2005185897A JP 2005185897 A JP2005185897 A JP 2005185897A JP 2003427881 A JP2003427881 A JP 2003427881A JP 2003427881 A JP2003427881 A JP 2003427881A JP 2005185897 A JP2005185897 A JP 2005185897A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
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- Y02C20/30—Capture or disposal of greenhouse gases of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]
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Abstract
Description
本発明は、ガス絶縁開閉装置などの絶縁媒体、LSIのドライエッチング剤あるいはフッ素化剤として使用されている六フッ化硫黄ガスの処理方法に関するものである。 The present invention relates to a method for treating sulfur hexafluoride gas used as an insulating medium such as a gas insulated switchgear, an LSI dry etching agent or a fluorinating agent.
六フッ化硫黄ガス(SF6)は、ガス絶縁開閉装置などの絶縁媒体として多量に使われている。また近年、LSIのドライエッチング剤あるいはフッ素化剤としても注目され、その需要も年々増加している。これら六フッ化硫黄ガスを使用する場合には、その残ガス等の排気の際にその除害が常に必要となる。特に六フッ化硫黄ガスは、オゾン破壊係数(ODP)や地球温暖化係数(GWP)が高く、近年国際的に大きな問題となっている。 Sulfur hexafluoride gas (SF 6 ) is used in large quantities as an insulating medium for gas insulated switchgear and the like. In recent years, it has attracted attention as an LSI dry etching agent or fluorinating agent, and its demand is increasing year by year. When these sulfur hexafluoride gases are used, it is always necessary to remove them when exhausting the residual gas. In particular, sulfur hexafluoride gas has a high ozone depletion potential (ODP) and global warming potential (GWP), and has recently become a major international problem.
これら六フッ化硫黄ガスは、大気中で極めて安定であり、水にもわずかしか溶解しないため、アルカリ薬剤を用いた除害装置や湿式スクラバーといった従来の除害技術では完全に処理ができない。また、燃焼ガスや熱を利用した分解による除害技術においては、六フッ化硫黄ガスが分解するものの未分解成分が残留したり、さらに除害困難な四フッ化硫黄ガスが生成したりする。 Since these sulfur hexafluoride gases are extremely stable in the atmosphere and are only slightly soluble in water, they cannot be completely treated by conventional abatement techniques such as abatement equipment using an alkaline chemical or a wet scrubber. Moreover, in the detoxification technique by decomposition using combustion gas or heat, although the sulfur hexafluoride gas is decomposed, undecomposed components remain, or sulfur tetrafluoride gas that is difficult to remove is generated.
本出願人は、NF3の処理方法として、Siを始めとする各種金属、およびこれらの非酸化物系化合物とNF3を200℃〜800℃で反応させ、得られるフッ化物ガスを補集する方法を提案した(特許文献1)。しかしながらこの反応処理方法は、六フッ化硫黄ガスにおいては、必要な処理速度を得ようとするためには反応温度を高くしなければならず処理に余分の熱エネルギーを要し、反応器に要求される材質も高級品質なものになるという問題があった。また、六フッ化硫黄ガスをアルミナ(Al2O3)の存在下で分子状の酸素や水蒸気を接触させて分解処理をすること(特許文献2、特許文献3)が、開示されているが完全ではない。 As a method for treating NF 3 , the present applicant reacts various metals including Si and non-oxide compounds thereof with NF 3 at 200 ° C. to 800 ° C., and collects the fluoride gas obtained. A method was proposed (Patent Document 1). However, in this reaction processing method, in order to obtain a required processing speed in the case of sulfur hexafluoride gas, the reaction temperature must be increased, and extra heat energy is required for the processing, which is required for the reactor. There was a problem that the quality of the material to be used was of a high quality. Further, it is disclosed that sulfur hexafluoride gas is decomposed by contacting molecular oxygen or water vapor in the presence of alumina (Al 2 O 3 ) (Patent Documents 2 and 3). incomplete.
本発明は、この様な点に着目してなされたもので、処理速度の低下がない六フッ化硫黄ガスの除害方法を提供することを目的とする。
本発明者らは、かかる問題点に鑑み鋭意検討の結果、常温では反応性が低く除害処理が困難な六フッ化硫黄ガスを、触媒を含有した酸化珪素を用い、フッ化珪素ガスおよび酸化硫黄ガスを生成させ、そのフッ化珪素ガスおよび酸化硫黄ガスを処理することで、容易かつ安価に六フッ化硫黄ガスを除害処理できることを見いだし、本発明に到達したものである。 As a result of intensive investigations in view of such problems, the present inventors have used sulfur hexafluoride gas, which has low reactivity at room temperature and is difficult to perform detoxification, and silicon oxide containing a catalyst. The inventors have found that sulfur hexafluoride gas can be easily and inexpensively treated by generating sulfur gas and treating the silicon fluoride gas and sulfur oxide gas, and the present invention has been achieved.
すなわち本発明は、六フッ化硫黄ガスを含む排ガスと処理剤とを接触させて当該排ガスから六フッ化硫黄ガスを除去する排ガスの処理方法において、前段で処理剤として触媒を含有した酸化珪素を用い、フッ化珪素ガスおよび酸化硫黄ガスを生成させ、後段で該生成ガスをアルカリ薬剤充填筒または湿式スクラバーで処理することを特徴とする六フッ化硫黄ガスの処理方法を提供するものである。 That is, the present invention provides an exhaust gas treatment method for removing sulfur hexafluoride gas from exhaust gas by contacting the exhaust gas containing sulfur hexafluoride gas with the treatment agent. The present invention provides a method for treating sulfur hexafluoride gas, characterized in that silicon fluoride gas and sulfur oxide gas are produced, and the produced gas is treated with an alkali chemical filling tube or a wet scrubber at a later stage.
以下、本発明の内容を詳細に述べる。 Hereinafter, the contents of the present invention will be described in detail.
本発明に用いる触媒を含有させた酸化珪素は、六フッ化硫黄ガスとの反応により、フッ化珪素ガスおよび酸化硫黄ガスを生成させる。フッ化珪素ガスは、SiF4、SiOF2、Si2OF6等であり、主にSiF4を生成させる。また、酸化硫黄ガスは、SO2、SOF2、SO2F2等であり、主にSO2を生成させる。 Silicon oxide containing a catalyst used in the present invention generates silicon fluoride gas and sulfur oxide gas by reaction with sulfur hexafluoride gas. The silicon fluoride gas is SiF 4 , SiOF 2 , Si 2 OF 6 or the like, and mainly generates SiF 4 . The sulfur oxide gas is SO 2 , SOF 2 , SO 2 F 2, etc., and mainly generates SO 2 .
次に、含有させる触媒は、Pt、Pd、Al2O3、Ga2O3、またはZnOである。これら触媒は、単独で含有させることもできるし、二種以上の混合物として含有させることもできる。また、触媒の量は、酸化珪素に対して、0.01〜5重量%の範囲が好ましい。0.01重量%未満だと触媒の効果が小さく好ましくなく、5重量%超だと酸化珪素とガスとの接触が少なくフッ化珪素ガスを生成できないため好ましくない。また、処理剤の加熱温度は、100〜1000℃の範囲が好ましい。100℃未満だと反応速度が低く十分な反応効率が得られず、1000℃を超えると酸化珪素や含有する触媒が軟化し、もしくは溶融し、ガスとの接触が充分なされなくなるため好ましくない。 Next, the catalyst to be included is Pt, Pd, Al 2 O 3 , Ga 2 O 3 , or ZnO. These catalysts can be contained alone or as a mixture of two or more. The amount of the catalyst is preferably in the range of 0.01 to 5% by weight with respect to silicon oxide. If it is less than 0.01% by weight, the effect of the catalyst is small and not preferable, and if it exceeds 5% by weight, the contact between silicon oxide and gas is small and silicon fluoride gas cannot be generated. The heating temperature of the treatment agent is preferably in the range of 100 to 1000 ° C. If it is less than 100 ° C., the reaction rate is low and sufficient reaction efficiency cannot be obtained, and if it exceeds 1000 ° C., the silicon oxide and the contained catalyst are softened or melted, and contact with the gas is not sufficient.
最後に、生成されたフッ化珪素ガスおよび酸化硫黄ガスは、後段で水酸化カルシウム等のアルカリ薬剤を用いたアルカリ除害剤充填筒や水を使用した湿式スクラバー等の従来の除害技術で処理される。アルカリ除害剤充填筒では円筒内に水酸化カルシウムを主成分としたφ2〜5mm程度の粒状あるいは塊状に成形した除害剤が充填されており、上部から流入された上記生成ガスが、筒内で除害処理される。筒内では(1)式、(2)式のような反応式により上記ガス成分が固化し処理される。一方、湿式スクラバーでは円筒内の上部から水をノズルより噴射し分散させて、下部から流入された上記生成ガスが、ガスと水との接触により除害処理される。筒内では(3)式、(4)式のような反応式によりガス成分が液化あるいは固化し処理される。 Finally, the generated silicon fluoride gas and sulfur oxide gas are treated with conventional detoxification technologies such as an alkali detoxifying agent-filled cylinder using an alkali chemical such as calcium hydroxide and a wet scrubber using water in the subsequent stage. Is done. In the cylinder filled with an alkaline pesticide, the cylinder is filled with a pesticide formed in a granular or lump shape of about 2 to 5 mm mainly composed of calcium hydroxide. Detoxification treatment. In the cylinder, the gas component is solidified and processed by reaction equations such as equations (1) and (2). On the other hand, in the wet scrubber, water is sprayed from the upper part in the cylinder and dispersed, and the generated gas introduced from the lower part is detoxified by contact between the gas and water. In the cylinder, the gas component is liquefied or solidified by reaction equations such as equations (3) and (4).
SiF4<気体>+2Ca(OH)2 <固体>
→SiO2<固体>+4CaF2<固体>+O2<気体>・・・(1)
2SO2<気体>+2Ca(OH)2 <固体>
→2CaSO3<固体>+H2O<液体> ・・・(2)
SiF4<気体>+2H2O<液体>
→SiO2<固体>+4HF<液体> ・・・(3)
SO2<気体>+H2O<固体>
→H2SO3<液体> ・・・(4)
SiF 4 <Gas> + 2Ca (OH) 2 <Solid>
→ SiO 2 <solid> + 4CaF 2 <solid> + O 2 <gas> (1)
2SO 2 <Gas> + 2Ca (OH) 2 <Solid>
→ 2CaSO 3 <solid> + H 2 O <liquid> (2)
SiF 4 <Gas> + 2H 2 O <Liquid>
→ SiO 2 <Solid> + 4HF <Liquid> (3)
SO 2 <Gas> + H 2 O <Solid>
→ H 2 SO 3 <Liquid> (4)
以上詳述したように、本発明の方法によれば六フッ化硫黄ガスを含む排ガスと処理剤とを接触させて当該排ガスから六フッ化硫黄ガスを除去する排ガスの処理方法において、前段で処理剤として触媒を含有させた酸化珪素を用い、フッ化珪素ガスおよび酸化硫黄ガスを生成させ、後段でそれら生成ガスを処理することにより、六フッ化硫黄ガスを容易かつ安価に処理することができる。 As described in detail above, according to the method of the present invention, in the exhaust gas treatment method for removing sulfur hexafluoride gas from the exhaust gas by bringing the exhaust gas containing sulfur hexafluoride gas into contact with the treatment agent, the treatment is performed in the previous stage. By using silicon oxide containing a catalyst as an agent, silicon fluoride gas and sulfur oxide gas are produced, and the produced gas is treated at a later stage, whereby sulfur hexafluoride gas can be treated easily and inexpensively. .
以下、実施例により具体的に説明するが、かかる実施例に限定されるものではない。 Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to such examples.
実施例1〜9、比較例1〜2
図1に本発明方法による六フッ化硫黄ガスの処理確認のための実験フローの概略図を示す。処理対象となる排ガスを含んだサンプルガス1で、このガスを触媒を含有した酸化珪素を充填した充填筒2に導入し接触させる。その充填筒2は、加熱ヒータ3により加熱し、充填筒2内部を加熱する。充填筒出口には、切替弁4があり、出口ガスを後段のアルカリ薬剤充填筒5、または湿式スクラバー6に切り替えて処理する。これらでは、前段で生成したフッ化珪素ガスおよび酸化硫黄ガスを処理することが可能となる。さらにそれらの下流は、前段のみを通過したガスと後段を通過したガスとを切り替えるための切替弁7があり、それぞれのガスをフーリエ変換式赤外線吸光分析装置(FT−IR)8に接続し、処理状態を確認できる。
Examples 1-9, Comparative Examples 1-2
FIG. 1 shows a schematic diagram of an experimental flow for confirming the treatment of sulfur hexafluoride gas by the method of the present invention. A sample gas 1 containing exhaust gas to be treated is introduced into and contacted with a filling cylinder 2 filled with silicon oxide containing a catalyst. The filling cylinder 2 is heated by the heater 3 to heat the inside of the filling cylinder 2. A switching valve 4 is provided at the outlet of the filling cylinder, and the outlet gas is switched to the subsequent alkaline chemical filling cylinder 5 or the wet scrubber 6 for processing. In these, it becomes possible to process the silicon fluoride gas and sulfur oxide gas generated in the preceding stage. Further downstream of them, there is a switching valve 7 for switching between the gas that has passed through the former stage and the gas that has passed through the latter stage, and each gas is connected to a Fourier transform infrared absorption spectrometer (FT-IR) 8. You can check the processing status.
実施例1においては、処理対象ガスとしてSF6=1000ppmを含む窒素ガスを用い、処理剤としてPtを0.1重量%含有させたSiO2を用いた。この充填筒加熱温度は700℃とした。この処理対象ガスを毎分500cm3程度導入し接触させた。反応で生成したフッ化珪素ガスおよび酸化硫黄ガスをアルカリ薬剤充填装置(アルカリ薬剤は、酸化カルシウムを使用)で処理した後、フーリエ変換式赤外線吸光分析装置で確認した。その結果、SF6は、検出下限の5ppm以下であり、良好に処理されていることが確認できた。また、反応で生成したフッ化珪素ガスおよび酸化硫黄ガスを湿式スクラバーで処理した後においても、同様に良好に処理されていることが確認できた。前段での反応生成物をフーリエ変換式赤外線吸光分析装置で定量分析した結果、式(5)で示されるような化学反応式により、四フッ化珪素であるSiF4および二酸化硫黄であるSO2が生成したものと考えられる。 In Example 1, nitrogen gas containing SF 6 = 1000 ppm was used as the gas to be processed, and SiO 2 containing 0.1 wt% Pt was used as the processing agent. The filling tube heating temperature was 700 ° C. About 500 cm 3 of this processing target gas was introduced per minute and contacted. The silicon fluoride gas and sulfur oxide gas generated by the reaction were treated with an alkali chemical filling device (alkali chemical used calcium oxide), and then confirmed with a Fourier transform infrared absorption spectrometer. As a result, SF 6 was 5 ppm or less, which is the lower limit of detection, and it was confirmed that the treatment was good. In addition, it was confirmed that the silicon fluoride gas and sulfur oxide gas produced by the reaction were similarly treated well after being treated with a wet scrubber. As a result of quantitative analysis of the reaction product in the former stage using a Fourier transform infrared absorption spectrometer, SiF 4 as silicon tetrafluoride and SO 2 as sulfur dioxide were found to be in accordance with a chemical reaction formula as shown in formula (5). It is thought that it was generated.
2SF6+3SiO2→3SiF4+2SO2+O2・・・(5)
比較のため、Ptを含まないSiO2を用い、700℃、1000℃で実施例1と同様のガス処理を行った。その結果、表1に示したようにSF6は完全に除去できなかった。
2SF 6 + 3SiO 2 → 3SiF 4 + 2SO 2 + O 2 (5)
For comparison, the same gas treatment as in Example 1 was performed at 700 ° C. and 1000 ° C. using SiO 2 not containing Pt. As a result, SF 6 could not be completely removed as shown in Table 1.
次に、実施例1と同様な方法で、処理対象ガスとして、SF6=1000ppmを含む窒素ガスを用い、触媒にPt、Pd、Al2O3、Ga2O3、ZnOの単一物質または混合物を用いた。触媒の濃度はいずれも0.1重量%とした。混合物の場合は、それぞれの成分がすべて0.1重量%となるようにした。この充填筒の加熱温度は500〜650℃とした。反応で生成したフッ化金属ガスをアルカリ薬剤充填装置および湿式スクラバーで処理した後、フーリエ変換式赤外線吸光分析装置で確認した結果、いずれの分析方法においても、SF6の検出下限の5ppm以下であり、良好に処理されていることが確認できた。これらの条件及び結果を表1に示した。 Next, in the same manner as in Example 1, a nitrogen gas containing SF 6 = 1000 ppm was used as the gas to be treated, and the catalyst was a single substance of Pt, Pd, Al 2 O 3 , Ga 2 O 3 , ZnO or A mixture was used. The catalyst concentration was 0.1% by weight. In the case of a mixture, all the components were adjusted to 0.1% by weight. The heating temperature of this filling cylinder was 500-650 degreeC. After processing the metal fluoride gas generated by the reaction with an alkali chemical filling device and a wet scrubber, the results were confirmed with a Fourier transform infrared absorption spectrometer. As a result, in any analysis method, the detection lower limit of SF 6 was 5 ppm or less. It was confirmed that it was treated well. These conditions and results are shown in Table 1.
実施例10〜12
実施例1と同様な方法で、処理対象ガスとして、SF6=1000ppmを含む窒素ガスを用い、触媒にPtを用いた。触媒の濃度は、0.01重量%、1重量%、5重量%とし、加熱温度は、700℃とした。その結果、SF6の検出下限の5ppm以下であり、良好に処理されていることが確認できた。これらの条件及び結果を表1に示した。
Examples 10-12
In the same manner as in Example 1, nitrogen gas containing SF 6 = 1000 ppm was used as the gas to be treated, and Pt was used as the catalyst. The catalyst concentration was 0.01 wt%, 1 wt%, 5 wt%, and the heating temperature was 700 ° C. As a result, it was 5 ppm or less of the detection lower limit of SF 6 , and it was confirmed that the treatment was good. These conditions and results are shown in Table 1.
1・・・サンプルガス(六フッ化硫黄+窒素)
2・・・触媒を含有した酸化珪素の充填筒
3・・・充填筒加熱ヒータ
4・・・切り替え弁
5・・・アルカリ薬剤充填装置
6・・・湿式スクラバー
7・・・切り替え弁
8・・・フーリエ変換式赤外線吸光分析計
1 ... Sample gas (sulfur hexafluoride + nitrogen)
2 ... Filling tube 3 of silicon oxide containing catalyst 3 ... Filling tube heater 4 ... Switching valve 5 ... Alkaline chemical filling device 6 ... Wet scrubber 7 ... Switching valve 8 ...・ Fourier transform infrared absorption spectrometer
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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RU2468993C1 (en) * | 2011-03-30 | 2012-12-10 | Открытое Акционерное Общество "Российский научно-исследовательский и проектный институт титана и магния" (ОАО "РИТМ") | Method of recycling waste gases, formed in process of obtaining pyrogenic silicon dioxide by high-temperature hydrolysis of silicon chlorides |
WO2013125791A1 (en) * | 2012-02-23 | 2013-08-29 | (주) 파인텍 | System for separating and reusing perfluorocarbon compound |
WO2013125792A1 (en) * | 2012-02-23 | 2013-08-29 | (주) 파인텍 | System for separating and reusing perfluorocarbon compound |
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
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RU2468993C1 (en) * | 2011-03-30 | 2012-12-10 | Открытое Акционерное Общество "Российский научно-исследовательский и проектный институт титана и магния" (ОАО "РИТМ") | Method of recycling waste gases, formed in process of obtaining pyrogenic silicon dioxide by high-temperature hydrolysis of silicon chlorides |
WO2013125791A1 (en) * | 2012-02-23 | 2013-08-29 | (주) 파인텍 | System for separating and reusing perfluorocarbon compound |
WO2013125792A1 (en) * | 2012-02-23 | 2013-08-29 | (주) 파인텍 | System for separating and reusing perfluorocarbon compound |
KR101410914B1 (en) | 2012-02-23 | 2014-06-24 | (주)파인텍 | The separation and recycling system for a perfluoro compounds |
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