| dc.description.abstract | Perfluorinated compounds (PFCs) have great potentials in causing global warming and they may exist in the atmosphere for thousands of years. Therefore, emission of PFCs and its associated global warming attract more and more public attention. To effectively alleviate the increasingly deteriorated phenomenon, the Kyoto Environmental Regulatory Council in 1997 reached a consensus to abate CO2, CH4, PFCs, HPFCs, N2O emissions. In addition to increase the efficiency of utilizing PFCs, the semiconductor industry applied alternative chemicals, recovery/recycle systems and abatement techniques. Owing to difficult development in alternative chemicals and high cost in recovery/recycle systems, the abatement techniques turns to be the primary way to control PFCs emission at present stage. This study investigates the feasibility of applying dielectric barrier discharge (DBD) technology for destroying and removing PFCs from gas streams. The target PFCs selected for this study is SF6, which is commonly used in semiconductor industry as etching carrier or in power industry as insulator. A bench-scale experimental apparatus has been designed and constructed in this study for evaluating the effectiveness of DBD for SF6 removal. Dependencies of removal efficiency achieved with DBDs on operating parameters including applied voltage, composition of the gas stream, applied frequency and oxygen concentration, and power consumption are also investigated. Experimental results indicate that operating the system at higher oxygen gases and applied voltage can enhance the removal efficiency of SF6 achieved with DBD. However, high concentrations of O2 in the gas stream may actually decrease the removal efficiency due to their electronegative properties. More than 91% removal efficiencies have been achieved with this apparatus for SF6 when 20 kV is applied for the gas stream containing [SF6]/[O2]/[Ar]/[N2] = 300 ppmv: 12%: 40%: N2 balance at 293 K, 1atm. In addition, 73% removal efficiencies for SF6 have been achieved with this apparatus combined with catalysts for the gas stream containing [SF6]/[O2]/[Ar]/[N2] = 300 ppmv: 20%: 40%: N2 balance at 293 K, 1atm. The energy yield of SF6 achieved with plasma combined catalysis(CPC) were significantly higher than this apparatus without packed catalysts. With the application of DBD, SF6 molecules can be dissociated and oxidized to other smaller molecules (i.e. SO2, SO2F2 and SOF4). This preliminary study demonstrates the feasibility of applying a novel technology for destroying and removing PFCs from gas streams. Further research should be carried out to identify and quantify the final by-products for better understanding of the removal mechanisms. | en_US |