Removal of C3F8 via the Combination of Non-thermal Plasma, Catalysis and Adsorption

• Main Authors: Bor-yuan Lin, 林渤原
• Other Authors: Moo-been Chang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/96246372479616041384

碩士 === 國立中央大學 === 環境工程研究所 === 98 === With the characteristics of extremely long lifetimes and high GWPs (global warming potentials), PFCs are regulated as one of the GHGs (greenhouse gases) in Kyoto Protocol. In recent years, C3F8, one of the perfluorocompounds (PFCs), has been gradually replacing CF4 and C2F6 as the CVD (chemical vapor deposition) chamber cleaning gas used in high-tech industry. In terms of PFC abatement, the high temperature-based technologies, such as catalytic oxidation and thermal decomposition, are still the mainstream. Although acceptable removal efficiency could be achieved, these equipments have to be maintained at a certain temperature even during the period without PFC emission. Unlike the above-mentioned technologies, nonthermal plasma can be ignited and operated at room temperature, making it a potentially viable technique for PFC abatement. However, prior to further industrial application, the energy efficiency and the products’ selectivities still need to be improved. To resolve these challenges, a novel technique, combining the nonthermal plasma, adsorption and catalysis (CPAC) simultaneously, is developed in this study. This technique is proposed based on the concept that adsorption and catalysis could enhance the energy efficiency and products’ selectivities theoretically. The main purpose of this study is to demonstrate the feasibility of abating PFC via CPAC. The CPAC was constructed by introducing almost the same volumes of both packed-bed materials either as single-component layers or as a mechanical mixture. In addition to CPAC, the combinations of plasma with catalysis or adsorption alone, which are termed as CPC and CPA, are used as control as well. The experimental results indicate that the C3F8 removal efficiencies obtained by different reactors are in the order as: single-component layers of CPAC (85.9%) > CPA (85%) > CPC (74.1%) > mechanical mixture of CPAC (71.8%), as the specific input energy (SIE, the ratio of discharge power to gas flow rate) is fixed at 34.8 kJ/L. For the different reactors tested in this study, the products detected after plasma treatment include CO2, CO, N2O and CF4. The formation of C2F6 is not observed in this study. The CO2 selectivity obtained at 34.8 kJ/L is in the sequence of single-component layers of CPAC (82.5%) > CPA (81.1%) > CPC (73.5%) > mechanical mixture of CPAC (68.6%). In summary, the removal efficiency of C3F8 and CO2 selectivity achieved with single-component layers of CPAC is greater than CPA, CPC, and mechanical mixture of CPAC.