Effects of phosphorus and saccharide on size, shape, and reducibility of Fischer–Tropsch catalysts for slurry phase and fixed-bed reactions

Authors: Kyoung-Su Ha, Gyu-In Jung, Min-Hee Woo, Ki-Won Jun, Jong Wook Bae

Abstract:
Saccharide was incorporated into Co/Al₂O₃ by impregnating sucrose and a cobalt precursor on a phosphorus-treated -Al₂O₃ support (P-Al₂O₃), to control the catalyst size, shape, and reducibility. The effects of P-Al₂O₃ on the relationship between C₅₊ productivity, dispersion, and reducibility were investigated and compared with our previous work based on the high surface area -Al₂O_3. Powder Xray diffraction results for Co/P-Al₂O₃ revealed that the addition of P increased the average size of the cobalt oxide crystals due to weakened interactions between the metal and the support, which led to the increased reducibility while compromising the dispersion. The extraordinarily enhanced hydrothermal stability ofthe catalysts was corroborated with the help of FT-IR analysis. Activity tests were conducted in a fixed-bed reactor as well as in a slurry phase reactor charged with Co/P-AAl₂O₃ catalysts to investigate the reactor behavior. The addition of a saccharide, such as sucrose, efficiently increased the dispersion capability and regulated crystal shape to overcome the lowered dispersion caused by phosphorus treatment. The effect of sucrose on crystal size and shape of Co/P-AAl₂O₃ was verified through TEM imaging and XRD analysis. The control of crystal size and shape was found to be crucial to attain maximum productivity, in addition to dispersion and reducibility.

Keywords:
Cobalt
Dispersion
Fischer–Tropsch
Hydrogenation
Reduction

Published in: Applied catalysis A: General  (Volume 453, Pages 1-402, 26 February 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Effects of phosphorus and saccharide on size, shape, and reducibility of Fischer–Tropsch catalysts for slurry phase and fixed-bed reactions

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