INFLUENCE OF INTERMEDIATE IRON REDUCED SPECIES IN FISCHER-TROPSCH SYNTHESIS USING Fe/C CATALYSTS

J. F. BENGOA, A. M. AVAREZ, M. V. CAGNOLI, N. G. GALLEGOS AND S. G. MARCHETTI

Natal, Brasil

Simposio; 8th Natural Gas Conversion Symposium; 2007

Instituto Brasileiro de Petróleo e Gás - IBP

The Fischer-Tropsch synthesis (FTS) has been previously studied using catalysts of Fe supported on different substrates, such as SiO2, Al2O3, MgO, zeolites. It is well known that in these systems it is very hard to reach a complete metal reduction when the iron loading is lower than 10% w/w [1, 2]. In these cases, intermediates iron species (Fe2+ and/or Fe3+) are present on the fresh reduced catalyst jointly with the Feº. Notwithstanding, the role played by these intermediate species, in the synthesis, is still unknown. To carry out the study above mentioned it is necessary to have a support that allow a complete iron reduction. In this way we have chosen a carbon support due to its low metal-support interaction. Since, some reactions involved in FTS are “sensitive to structure”, it is necessary to prepare catalysts with similar Feº crystal diameters in order to avoid the influence of this parameter. With the aim to determine the effect of the intermediate iron reduced species on the activity and selectivity on the FTS, two Fe/C catalysts with different reduction degree were prepared, catalytically tested and the results were correlated with its structural properties.