以電漿觸媒系統去除氣流中CFC-12及HCFC-22之可行性探討;Removal of CFC-12 and HCFC-22 from Gas Stream via Combined Plasma Catalysis

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Title:	以電漿觸媒系統去除氣流中CFC-12及HCFC-22之可行性探討;Removal of CFC-12 and HCFC-22 from Gas Stream via Combined Plasma Catalysis
Authors:	溫馨;Wen, Shin
Contributors:	環境工程研究所
Keywords:	臭氧破壞物質;電漿觸媒;CFC;HCFC;全球暖化;CFC;Global warming;Ozone depleting substances;Plasma catalysis;HCFC
Date:	2020-08-24
Issue Date:	2020-09-02 19:38:13 (UTC+8)
Publisher:	國立中央大學
Abstract:	工業及生活中常用的冷媒材料為含鹵素之化合物，如氟氯碳化合物(chlorofluorocarbons, CFCs)或含氫之氟氯碳化合物(hydrochlorofluorocarbons, HCFCs)。由於CFCs及HCFCs的化學穩定性，最終將由對流層擴散至平流層，並經由光解反應釋出氯原子進而破壞平流層臭氧，此外CFCs及HCFCs具高全球暖化潛勢(Global warming potential, GWP)對全球暖化亦有影響，現行處理CFCs及HCFCs相關技術包括高溫焚化、觸媒催化及電漿技術等。本研究旨在分析電漿觸媒系統對於氣流中CFC-12及HCFC-22之去除效率及機制，並可分成三個部分：(1)去除CFC-12及HCFC-22之電漿觸媒系統開發；(2)進行電漿觸媒之機制分析；(3) 評估其可行性與對環境之效益。結果顯示利用電漿觸媒法具有去除CFC及HCFC之可行性，在進流濃度為800 ppm、總流量為500 sccm、添加1%O2且操作電壓為17 kV時，CFC-12及HCFC-22之最高去除效率分別達99.0%及99.4%，其能量效率分別為4.9 g/kWh及3.3 g/kWh；CFC-12及HCFC-22經電漿反應後生成之副產物主要為CO2、NOX，此外因氮分子之解離能、電離電勢較激發為亞穩態分子N2(A3∑u+)高，加上CFC-12及HCFC-22具有較大的解離性電子反應截面易與高能電子反應，其去除機制主要經由電漿產生之N2(A3∑u+)及高能電子進行分解反應。;Halogen-containing compounds including chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are widely used in industry. Due to their chemical stability, CFCs and HCFCs, gradually diffuse from the troposphere to the stratosphere and catalyze the destruction of ozone through photodegradation. In addition, high global warming potentials (GWP) of CFCs and HCFCs also aggravate global warming. Current technologies for treating CFCs and HCFCs include high-temperature incineration, catalysis, and plasma destruction. This study aims to develop a catalyst with good activity and combine it with a plasma reactor as a hybrid system for the removal of CFC-12 and HCFC-22. The study is divided into three parts: (1) Development of plasma catalyst system for removing CFC-12 and HCFC-22 (2) Elucidation of plasma catalysis mechanism (3) Assessment of feasibility and environmental benefit. The results show that combined plasma catalyst system is effective in removing CFC-12 and HCFC-22. The highest removal efficiencies of CFC-12 and HCFC-22 are 99.0% and 99.4% respectively as the operating conditions are controlled at applied voltage=17 kV, gas flow rate= 500 sccm, CFC-12 or HCFC-22= 800 ppm and O2= 1%. The byproducts produced by plasma reaction of CFC-12 and HCFC-22 are CO2, and NOX. The dissociation energy and ionization potential of nitrogen molecules are higher than that of excited metastable molecules (N2(A3∑u+)). In addition, CFC-12 and HCFC-22 are easy to react with high-energy electrons and have large dissociative electron reaction cross sections. Therefore, the main removal mechanism is the decomposition reaction of N2(A3∑u+) and high-energy electrons generated by plasma.
Appears in Collections:	[Graduate Institute of Environmental Engineering ] Electronic Thesis & Dissertation

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