| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 97 === Perfluorinated compounds (PFCs) are one greenhouse gases that Kyoto Protocol aimed to reduce to prevent global warming from anthropogenic emissions of various greenhouse gases. Due to the high global warming potential, emissions of PFCs have caused much public concern. PFCs are widely used in the semiconductor and photonic industry for plasma etching and chamber clean. Since Kyoto Protocol has come into effect, more efforts are made to develop more efficient strategies for abating PFCs.
Among the various strategies for PFCs abatements, destruction is still the better choices. Non-thermal plasma technologies have been demonstrated to be effective in removing a variety of gaseous pollutants. However, the performance of the plasma system still has some room for improvement. The energy efficiency and product selectivity are the drawbacks which have to be modified. Hence, this study applies nonthermal plasma discharge to remove C¬3F8¬ and investigates the system performance in the various inner electrodes and dielectric material of the reactor for dielectric barrier discharge (DBD), and the interaction of the plasma and catalyst in combined plasma catalysis (CPC).
In this study, it is indicated the addition of O2 could enhance the removal efficiency for C3F8. The removal efficiency for C3F8 increases with the size of the inner electrode, and the “screw” shape of the inner electrode could have better performance. As for the dielectric material, ceramic may be better than quartz. The highest removal efficiency for C3F8 is 52 % with the 1/2”(screw) inner electrode, and ceramic, and the major by-product is CF4. Furthermore, the addition of Ar could improve the byproduct, and CF4, COF2, CO, CO2, NO are the major components. It could reduce the impact of global warming caused by PFCs emissions through the treatment of plasma discharge.
For C3F8 abatement, the plasma combined with γ-Al2O3 (with catalytic activity, PCR) have a better performance than that with α-Al2O3 (without catalytic activity, PBR). It is interesting to find that the enhancement of the energy efficiency and CO2 selectivity are from different mechanisms. The former is caused by the active species from plasma reaction, and the latter is mainly attributed to the active species from the decomposition of O3 on the surface of the catalyst so that CO could be oxidized to CO2.
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