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Cheon J.-Y.,Korea Research Institute of Chemical Technology | Cheon J.-Y.,Korea University | Kang S.-H.,Institute for Advances Engineering IAE | Bae J.W.,Korea Research Institute of Chemical Technology | And 4 more authors.
Catalysis Letters | Year: 2010

Fischer-Tropsch Synthesis (FTS) on Fe-Cu-K/ ZSM5 catalysts prepared by varying the amount of active components for a given amount of ZSM5 has been investigated to elucidate the effects of iron concentration. The catalysts were prepared by conventional wet impregnation method using ZSM5 and subsequently calcined at 500 °C for 5 h. The different catalytic performance is verified by the variation of microporosity such as surface area and pore size distribution of Fe-Cu-K/ZSM5, acidity, reducibility of active phases and the presence of various crystalline phases like α-Fe2O3, metallic iron and iron carbide. The characterization results are analyzed along with catalytic performance to arrive at optimum amount of active components and to obtain maximum selectivity of FTS products with high conversion of CO during FTS reaction.


Kang S.-H.,Institute for Advances Engineering IAE | Ryu J.-H.,Institute for Advances Engineering IAE | Kim J.-H.,Institute for Advances Engineering IAE | Sai Prasad P.S.,Indian Institute of Chemical Technology | And 3 more authors.
Catalysis Letters | Year: 2011

Fischer-Tropsch synthesis (FTS) reaction for the direct production of gasoline range hydrocarbons (C5-C9) from syngas was investigated on cobalt-based FTS catalyst supported on the ZSM-5 possessing a four different Si/Al ratio. The FTS catalysts were prepared by impregnation method using cobalt nitrate precursor in a slurry of ZSM-5, and they were characterized by surface area, XRD, H2-TPR and NH3-TPD. Cobalt supported catalyst on ZSM-5 having a low Si/Al ratio of 15 was found to be superior to the other catalysts in terms of better C5-C 9 selectivity due to the formation of small cobalt particle and the presence of larger number of weak acidic sites. It also exhibited the highest catalytic activity because of the higher reducibility and the small cobalt particle size. Graphical Abstract: Figure shows the variation of hydrocarbon selectivity and olefin selectivity in C2-C4 with increasing density of weak acid sites. As can be seen from the figure, the increase of the weak acidic site density is responsible for increasing C 5-C9 selectivity and olefin selectivity in C 2-C4 range hydrocarbons. Consequently, it could be stated that the enhancement of C5-C9 selectivity is preferable on the Co/ZSM-5 catalyst possessing a higher density of weak acid sites. © 2011 Springer Science+Business Media, LLC.


Baek S.-C.,Korea Research Institute of Chemical Technology | Baek S.-C.,Korea University | Kang S.-H.,Institute for Advances Engineering IAE | Bae J.W.,Sungkyunkwan University | And 3 more authors.
Energy and Fuels | Year: 2011

The effect of precursors, such as copper nitrate, acetate, and chloride, on the bifunctional Cu-ZnO/γ-Al2O3 catalysts was investigated for the direct dimethyl ether (DME) synthesis from syngas. The catalysts were characterized by measuring the reducibility and the surface area of metallic copper, together with their acidity. The well-dispersed copper particles with a high reducibility as well as a large amount of weak acidic sites on the bifunctional Cu-ZnO/γ-Al2O3 catalysts, prepared from a copper acetate precursor, are responsible for its high catalytic activity. The quantity of the acidic sites is a more crucial factor for obtaining a high DME yield than the surface area of metallic copper on the bifunctional catalyst. © 2011 American Chemical Society.


Ryu J.-H.,Institute for Advances Engineering IAE | Kang S.-H.,Institute for Advances Engineering IAE | Kim J.-H.,Institute for Advances Engineering IAE | Lee Y.-J.,Korea Research Institute of Chemical Technology | Jun K.-W.,Korea Research Institute of Chemical Technology
Korean Journal of Chemical Engineering | Year: 2015

The Fischer-Tropsch synthesis (FTS) reaction was investigated for the direct production of gasoline range hydrocarbons (C5-C9) from syngas on Ru-, Pt- and La-promoted Co-Al2O3/ZSM-5 (Si/Al=25) hybrid catalysts prepared by co-precipitation method in a slurry. The hybrid catalysts were characterized by BET surface area, XRD, H2-TPR and NH3-TPD analyses. Their physicochemical properties were correlated with the activity and selectivity of the catalysts. The promoted Co-Al2O3-(promoter)/ZSM-5 hybrid catalysts were superior to the unpromoted Co-Al2O3/ ZSM-5 catalyst in terms of better C5-C9 yield. In particular, the Co-Al2O3-Pt/ ZSM-5 hybrid catalyst exhibited the highest catalytic activity with a low C1 and olefin selectivity and a high C5-C9 selectivity. It could be due to not only a higher value for the reduction degree by H2-TPR, but also assigned to weak acidic sites of a low temperature desorption peak by NH3-TPD. © 2015, Korean Institute of Chemical Engineers, Seoul, Korea.

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