Role of ZSM5 Distribution on Co/SiO sub(2) Fischer-Tropsch Catalyst for the Production of C sub(5)-C sub(22) Hydrocarbons

• Published in: Energy & fuels Vol. 26; no. 10; pp. 6061 - 6069-6061-6069
• Main Authors: Kang, Suk-Hwan, Ryu, Jae-Hong, Kim, Jin-Ho, Jang, In Hyeok, Kim, ARong, Han, Gui Young, Bae, Jong Wook, Ha, Kyoung-Su
• Format: Journal Article
• Language: English
• Published: 18.10.2012
• Subjects: Catalysis; Catalysts; Cobalt; Cobalt oxides; Density; Hydrocarbons; Migration; Silicon dioxide; Synthesis
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/ef301251d

Fischer-Tropsch synthesis (FTS) for the production of gasoline and middle distillates in the range of C sub(5)-C sub(22) hydrocarbons was investigated using ZSM5-modified Co/SiO sub(2) FTS catalysts. The Co/SiO sub(2) catalyst was prepared by an impregnation method using a cobalt nitrate precursor in a slurry of SiO sub(2), and theh ZSM5-modified Co/SiO sub(2) catalyst was subsequently prepared by synthesizing ZSM5 (Si/Al ratio = 40) by in situ hydrothermal synthesis over the Co/SiO sub(2) catalyst at different ZSM5/(Co/SiO sub(2)) weight ratios. The catalytic performance was largely altered by changing acidity and reducibility of cobalt oxides on ZSM5-modified Co/SiO sub(2) catalysts due to the different extents of migration of cobalt oxides from SiO sub(2) to the ZSM5 surface with different degrees of catalytic olefin cracking reaction. The ZSM5-modified Co/SiO sub(2) catalyst with 25 wt %ZSM5 shows a maximum selectivity to C sub(5)-C sub(22) hydrocarbons with a high CO conversion due to the smaller cobalt crystallite size possessing a high reducibility and optimum acid site density. The superior catalytic performance on the ZSM5-modified Co/SiO sub(2) catalysts is mainly attributed to the modification of the Co/SiO sub(2) surface with the presence of adjacent ZSM5 particles and the possible migration of cobalt species from SiO sub(2) to the ZSM5 surface during the hydrothermal synthesis of ZSM5.