| 摘要: | PFCs(全氟碳化物)與 N2O 在高科技產業中被大量地使用，但因其具有
較高的全球暖化潛勢(Global warming potential)和較長的生命週期，皆被列為重要的溫室氣體。因此，針對 PFCs 與 N2O 開發有效之去除技術成為一重要議題。目前關於 PFCs 與 N2O 的排放控制方式除了利用替代化學物降低其使用量外，也有提高製程中的利用率、回收再利用和直接破壞消滅等方法，然而相較於開發替代化學物的困難、修改製程及回收再利用的高成本，處理削減目前較易著手之方向。本研究以非熱電漿結合觸媒系統針對PFCs ( CF4、C4F8)與 N2O 進行直接破壞消滅，研究 CF4、C4F8 及 N2O 在電漿中的分解效率，並透過改變不同參數，探討其中的反應機制。結果顯示當我們使用 γ-Al2O3 作為觸媒時對於 CF4、C4F8 及 N2O 的轉化都具有良好的活性，而在電漿觸媒系統當中 CF4、C4F8 及 N2O 三種汙染物皆有不錯的轉化效率，CF4 在 12 kV 下即可達 100%的轉化效率；C4F8 在 22 kV 下轉化效率也可達 100%；N2O 則是可維持在 90%的轉化效率。而產物的部分，CF4 及 C4F8 轉化之主要生成產物以 CO2、COF2 為主，在添加水氣時，亦有HF 的生成；而 N2O 轉化之主要生成產物推測為 N2、O2 及經 FT-IR 偵測到的 NO。本研究已證實非熱電漿結合觸媒系統以轉化 CF4、C4F8 及 N2O 之技術確實可行，且具有發展的潛力。
;PFCs (perfluorocarbons) and N2O are used extensively in the high-tech
industry, however, they are listed as greenhouses gas due to their high global
warming potentials and long lifetimes. Therefore, development of effective
removal technologies for reducing PFCs and N2O emissions has become an
important issue. At present, the emission control methods of PFCs and N2O
include the use of alternative chemicals, improvement of the utilization rate,
recycling and direct destruction. However, compared to the difficulty of
developing alternative chemicals, modifying the process and the high cost of
recycling, direct destruction is relatively simpler. In this study, a non-thermal
plasma combined with the catalyst system was used to convert the PFCs (CF4,
C4F8) and N2O. We studied the decomposition efficiencies of CF4, C4F8 and N2O
achieved with the plasma and changed the parameters to explore the reaction
mechanism. The results show that when γ-Al2O3 is used as a catalyst, good
activities for conversions of CF4, C4F8 and N2O are observed. In the plasma
catalysis system, 100% conversion efficiency of CF4 can be achieved at 12 kV;
for C4F8, 100% conversion efficiency can also be achieved 100% at 22 kV; N2O
can maintain conversion efficiency of 90%. The main products of the CF4 and
C4F8 conversions are mainly CO2 and COF2 with presence of O2. When water
vapor is added, HF is also formed. The main products of N2O conversion are
presumed as N2, O2 and NO. This study has confirmed that the non-thermal
plasma combined with the catalyst system to convert CF4, C4F8 and N2O is
indeed feasible and has good potential for further development. |
