Plasma assisted conversion of methane and carbon dioxide

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Several technologies including catalysis and plasma have already been proposed to improve the process involving conversion of methane and carbon dioxide into useful chemical intermediates. The conversions in dielectric-barrier discharges (DBD) or in gliding discharges (GD) were influenced significantly by discharge power, applied voltage, and catalysts. The detailed experience of the Warswava group in this field of non-thermal plasma applications including catalysts will be combined with a novel plasma source developed in Braunschweig. That source consists of electrodes (and distances between the electrodes) in the 10μm range allowing the generation and steering of plasmas at different discharge properties compared to DBD and GD. In addition, a sequential arrangement of these plasma sources is possible which allows a significant improvement in both efficiency and selectivity. The operating pressure can be as high as that of ambient air.Preliminary results obtained in Braunschweig show that many of the main products, C2H2, C2H4, C2H6, CH3COOH, CH3OH, HCHO, CO, H2, can be generated with efficiencies much better than10%. Since a catalyst placed in the discharges of the plasma affects the product distributions significantly, an even higher product yield than already observed can be expected. The mechanisms of product formation are still not understood and detailed analytics will be used, including on-line mass spectrometry, GC, laser induced fluorescence, FT-IR, optical emission spectroscopy (OES), and Cavity-Ring-Down (CRD) spectroscopy. The merits and drawbacks of either plasma technique will be assessed. The suitable technique or a combination of both will be identified and optimized. The CO2 reforming of methane using plasma-catalytic coupled process may be a source of desired products including ethylene and methanol, by one-stage operation. The selected process will be simple, exhibits low carbon production, and is not as energy intensive as Fischer-Tropsch. Some products (CH3COOH, CH3OH, HCHO) might even be found as a liquid.