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POTASSUM-CERIUM MOLTEN CHLORIDES FOR THE PARTIAL OXIDATION OF METHANE

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POTASSUM-CERIUM MOLTEN CHLORIDES FOR THE PARTIAL OXIDATION OF METHANE

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  1. The applications of molten salts have been well recognized for more than a century. In spite of the use of high temperature corrosive liquids, molten salts offer unique opportunities. Low temperature multi component molten salts, as well as room temperature ionic liquids have been developed for materials processing. Currently, molten salts are finding applications in fuel cell technology, in the field of separation processes of minor actinides from the rest of the fission products that are contained in the irradiated nuclear fuel, for the direct catalytic conversion of methane under mild conditions and the partial oxidation of methane to synthesis gas [1]. Here, we report the synthesis, characterization and behaviour of potassium-cerium (K-Ce) molten chlorides for the partial oxidation of methane. G. Lopes, A. Ferreira, A.P. Gonçalves and J.B. Branco Instituto Tecnológico e Nuclear, Estrada Nacional 10, 2686-953 Sacavém, Portugal Unidade de CiênciasQuímicas e Radiofarmacêuticas Introduction and Objective Experimental POTASSUM-CERIUM MOLTEN CHLORIDES FOR THE PARTIAL OXIDATION OF METHANE Catalysts Characterization XRD patterns for the molten salts Phase diagram of the eutectic mixture DSC tests before catalytic tests • XRD tests were performed before and after • the catalytic tests. • The melting of the salts under CO2 leads to • CeO2formation. • Melting temperatures around 150 ºC; • The addition and increase of cerium % increases • the transition temperature Catalytic Results • New features are not seen before and after the catalytic reaction. • Slight contraction of the CeO2 lattice is observed. The study of the combined Flow Rate (L/h) and CH4 / O2 molar ratio was undertaken. The outlet gas composition was analyzed on-line by gas chromatography (GC) with a thermal conductivity detector (TCD). Catalyst activity was defined as the number of mol of methane converted per mol of catalyst and per hour (molCH4/mol.h), m≈25 g. • Molar ratio CH4/O2 = 2 – mixture of compounds • Molar ratio CH4/O2 = 8 – Selectivity ~ 80% of CxHy • Higher molar ratios enhances the production of • hydrocarbons Effect of the CH4/O2 molar ratio at Flow Rate = 3 L/h Catalysts the selectivities at CH4/O2 molar ratio = 2 and Flow Rate = 3 L/h • The addition of cerium (wt%) influences the • conversion oh CH4 • CuCl-KCl-CeCl3 (10%) unusual behaviour • First time such results have been obtained Effect of the Flow Rate at CH4/O2 molar ratio = 2 Catalysts selectivities at CH4/O2 molar ratio = 8 and Flow Rate = 3 L/h References Acknowledgements [1] a) B. Mishraet al., Journal of Physics and Chemistry of Solids, 2005, 66, 396; b) T.R. Griffiths et al., Journal of Alloys and Compounds, 2006, 418, 116; c) J.J.Peng, et al., Applied Catalysis A: General, 2000, 201, L55; d) Y.G. Wei, et al., Journal of Natural Gas Chemistry, 2007, 16, 6. This work was supported by FCT, under contract number PTDC/QUI/72290/2006

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