Реферат: Light alcohols are very perspective convenient fuel for intermediate temperature solid oxide fuel cells (ITSOFC). Being economically sustainable, bioethanol is one of the most promising renewable fuels, its storage and transportation are easier than that of hydrogen, and internal steam reforming can be carried out directly inside the IT-SOFCs [1]. Realization of bio-ethanol steam reforming (ESR) over structured catalysts at short contact times promotes the increase of syngas output while using structured supports of good thermal conductivity providing an efficient heat transfer within the reactor prevents generation of hot spots and degradation of catalysts. The main problem in ESR of all oxygenates is carbon formation and sintering of cheap Ni-containing catalysts which are the most suitable for the practical application [2]. In the previous work, catalysts based on Ln ferritesnickelates were shown to provide a high activity, stability selectivity in ESR [3]. However, they have a low specific surface area (SSA) and cannot provide required performance being supported on structured substrates. The perspective approach to get over these difficulties is loading perovskites on the supports of a high SSA such as -Al2O3 with alkali-earth elements additives to prevent formation of coke. In the present work, the catalysts mLnNi1-x-yFexRuy 3/nMg- -Al2O3 (Ln = La, Pr, x= 0-0.6, y=0.1, m=10-20%wt, n=6-15%wt) were synthesized and tested in the ESR. The powder catalyst was supported on structured supports: platelets of ceramic or metal Ni-Al foams. Catalysts were characterized by XRD, BET, TEM with EDX, UV-vis, XPS and TPR-H2. ESR was carried out in the temperature range of 500-800°C in a plug-flow reactor at contact time 0.07s (fraction) and 0.15 s (platelets). Stability tests of structured catalysts were carried out in a pilot reactor in a realistic feed containing 30% C2H5OH+60% 2 +0÷2.5%O2+7.5÷10%N2. The SSA of catalysts was 100-110 m2/g. According to XRD data, the main phase is spinel with appearance of MgO at Mg concentration of 10-15%. The increase of the lattice parameter evidences Mg incorporation into the spinel structure. XPS analysis shows the enrichment of the support surface with Mg depending on the method of Mg addition. Supporting LnNi1-x-yFexRuy 3 results in further increase of γ-Al2O3 lattice parameter showing incorporation of Ni(Fe) in the substrate that is confirmed by UV-vis data. The absence of PrOx and RuOx reflections in XRD patterns of catalysts suggests their high dispersion. Testing of catalysts in ESR shows that hydrogen yield and stability of catalysts to coking depend on the Mg concentration achieving a maximum at n=10%. Selectivity to ethylene decreases with Mg concentration due to the decrease of acid Lewis centers concentration that favours formation of hydrogen-enriched carbonaceous species which are easier oxidized. The IR study in situ of surface intermediates and gas-phase products formed during interaction of ethanol and ethanol-water mixture with the catalysts shows that higher Mg concentration favours mainly formation of weakly bound monodentate ethoxy-groups of a high reactivity. Testing of catalysts on structured foam platelets revealed that, at temperatures below 750°C, ethanol conversion and hydrogen yield are higher for the optimized active component loaded on the metallic Ni-Al foam as compared with ceramic foam. Evidently, performance of Ni-Al foam supported catalyst is better due to its high thermal conductivity that provides effective heat transfer along the catalytic bed. A long-term testing of this catalyst in ESR and oxidative ethanol steam reforming (EOSR) using realistic reaction mixture shows its high activity and stability in both reactions. Acknowledgements Support by FP7 Project BIOGO and Russian Fund of Basic Research Project RFBR-CNRS 12-03-93115 is gratefully acknowledged.

Библиографическая ссылка: Arapova M.V. , Pavlova S.N. , Larina T.V. , Rogov V.A. , Krieger T.A. , Sadykov V.A. , Smorygo O.L. , Parkhomenko K.V. , Roger A.
Hydrogen and Syngas Production via Ethanol Steam Reforming over Supported Ferrites-Nikelates
The Energy & Materials Research Conference (EMR2015) 25-27 Feb 2015