We have been investigating conversion of syngas (CO: H2) to higher alkanes [Fischer-Tropsch (F-T) Process] in 5 μm and 25 μm channel microreactors coated with sol-gel encapsulated Fe/Co-nanocatalysts. These nano-metal-catalysts were incorporated into the sol-gel matrix by two methods: 1) metal nitrate solutions; 2) metal oxide nanoparticles. Characterization of these catalysts containing Co and Fe in alumina and silica sol-gel has been carried out by several techniques. The surface area measurements by BET method show an average specific surface area of 285 m2/g for alumina and 300 m2/g for silica sol-gel encapsulated catalysts. In order to optimize the sol-gel preparation and deposition in the microchannels, the elemental composition of sol-gel encapsulated catalyst was examined by EDX. The SEM and AFM images of the reactors before and after deposition of the catalysts have also been studied. Hydrogenation-reduction efficiency of the activated Fe-Co catalysts and the level of poisoning after the reaction were estimated using a vibrating sample magnetometer (VSM). The result suggests more efficient reduction in the case of the nano-particle metal oxides compared to that derived from metal nitrate solutions. In overall, 85% of the catalyst is poisoned after 25 hrs of catalytic reaction. The surface area and the syngas conversion results indicate that silica sol-gel matrix may be a better catalyst support. For alumina sol-gel support, higher conversion of syn-gas is observed with 25 μm microreactor channels. For silica sol-gel, syngas conversion as high as 73% has been achieved by adding Ru as a promoter to the Fe/Co catalyst mixture.
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C& EN, 18–19, July 21, 2003.
D. Schanke, A.M. Hilmen, E. Bergene, K. Kinnari, E. Rytter, E. Adnanes, A. Holmen.; Energy Fuel 10, 867 (1996).
S. Sun, N. Tsubaki and K. Fujimoto.; Applied Catalysis A: General 202, 121–131 (2000).
E. Iglesia; Applied Catalysis A: General 161, 59 (1997).
M.K. Niemela, A. Krause, T. Vaara, J. Kiviaho, M. Reinikainen.; Applied Catalysis A: General 147, 325 (1996).
R. Srinivasan et al.; AIChE Journal 43(11), 3059–3068 (1997).
W Ehrfeld, V Hessel, H Lowe; Microreactors: New Technology for Modern Chemistry, WILEY-VCH, Weinheim, ISBN3-527-29590-9, (2000).
L. Zhang, D. Xue.; Journal of Material Science Letters 21, 1931–1933 (2002).
M Madou; Fundamentals of Microfabrication: The Science of Miniaturization, Second Edition CRC Press, ISBN 0-8493-9451-1, (1997).
V. S. Nagineni et al.; Submitted to Chem. Mater.
S Zhao, PhD Dissertation, Louisiana Tech University, 2003.
K. Haas-Santo, M. Fichtner, K. Schubert, Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe, Germany.
Z Wang and Y. S. Lin.; Journal of Catalysis 174, 43–51 (1998).
S.V. Naidu, U. Siriwardane, A.N. Murty, N.S. Vegesna, J. Nwizugbu, J. Leonard, and C.R. Jones.; Microsc. Microanal. 9, 408, (2003).
We thank NSF EPSCoR for financial support of this work. We also thank Dr. K. Varahramyan and Mr. R. Aithal for their suggestions and help in this project.
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Kuila, D., Nagineni, V., Zhao, S. et al. Characterization of Alumina and Silica Sol-Gel Encapsulated Fe/Co/Ru Nanocatalysts in Microchannel Reactors for F-T Synthesis of Higher Alkanes. MRS Online Proceedings Library 820, 73–78 (2004). https://doi.org/10.1557/PROC-820-O3.4