Jl. Zhang et al., Role of supports in cobalt-based catalysts for Fischer-Tropsch synthesis of heavy hydrocarbons, CHIN J CATA, 22(3), 2001, pp. 275-278
The cobalt-based catalysts for F-T synthesis of heavy hydrocarbons were tes
ted in a down-flow fixed-bed reactor and characterized by using BET, TPR, H
-2-TPD, NH3-TPD, XRD, and XPS. The results indicated that the activity and
selectivity of the catalysts were influenced by the type and the surface pr
operties of the supports and the reaction conditions. There were different
product distributions over the catalysts with different supports. The heavy
hydrocarbons over Co/ZrO2, were amassed between C-10 and C-25. The C5+ pro
ducts over Co/SiO2 collected in C(9)similar toC(18). However, the heavy hyd
rocarbons over Co/Al2O3 centered in C(6)similar toC(13). It was found that
the acidity affected the active phase dispersion from the NH3-TPD and XRD r
esults. The TPR profiles showed that there was the interaction between coba
lt and,support and the Co/Al2O3 catalyst had the lowest reduction degree. T
he support effect on the catalytic reaction had a direct influence on the p
roduct distribution and chain growing probability. It was evident that the
supports also affected the surface concentration of active components. Howe
ver, the surface concentration of cobalt oxides did not increase with the r
ise of the support surface area and had no linear relationship with the cat
alytic activity.