OP-II-3

PP-II-46PARTIAL OXIDATION OF METHANE INTO HIGHERHYDROCARBONS IN PLASMA-CATALYST COMBINED SYSTEMDong Jin Suh, Jae-Wook Choi, Young-Woong SuhClean Energy Center, Korea Institute of Science & Technology,Cheongryang, Seoul 136-791, Korea, djsuh@kist.re.krDue to the depletion of oil and rise of oil price, the need for alternative chemicalfeedstock will be increasing in the near future. Methane, which is the principalcomponent of most natural gas reserves, is the cheapest and abundant source forhydrocarbons. Methane can be indirectly converted to liquid fuels or other chemicalsby way of synthesis gas, or directly transformed to C2 hydrocarbon or methanol. Theoxidative coupling of methane is one of promsing route for direct methane conversion[1,2]. The intensive studies have been carred out to develop new catalysts withhigher activity and selectivity for oxidative coupling of methane. However, efficientcatalyst has not been found yet. So, many studies on the methane conversion usingplasma processes are being performed as an alternative tool [3-5]. In plasmaprocesses, methane can be easily activated by energetic electrons. But it was verydifficult to control the reaction pathway to obtain the desired products under plasmastate. In this work, we utilized catalysts to enhance the activity and selectivity foroxidative coupling of methane. The performance of plasma-catalyst combinedsystem was evaluated in terms of conversion and selectivities.The dielectric barrier discharge was chosen as a plasma source due to easycontrol of plasma generation and low power consumption. Preliminary experimentsusing plasma without catalyst were carried out at the fixed applied voltage of 3 kV tofind the optimum experimental conditions. The methane to oxygen ratio was in therange of 4-8 and the total flow rate was fixed at 33 ml/min. The plasma zone wasvaried from 5 to 20 cm. The main products of converted methane were C2-C4hydrocarbons, carbon dioxide and synthesis gas (H 2 and CO). Experimental resultsshowed that metane conversion and hydrocarbon yields were increased withmethane to oxygen ratio and plasma zone. The highest C2 yield was about 12.5% atthe methane to oxygen ratio of 8 and the plasma zone of 20 cm. From these results,additional experiments using plasma with catalysts were conducted under the sameconditions. MgO, CeO 2 /MgO, La 2 O 3 /MgO, BaCl 2 /Nd 2 O 3 , Zeolite Y, FER, and MORcatalysts were employed in the bottom of plasma zone. The amount of catalysts417