(710c) Development of Rare-Earth Promoted Cobalt-Based Fischer-Tropsch Synthesis Catalysts with High Activity and Selectivity

Development of Rare-Earth Promoted
Cobalt-Based Fischer-Tropsch Synthesis Catalysts with High Activity and
Selectivity

Leilei He,?  Maohong Fan?µ*                                                                                             

?Department
of Chemical and Petroleum Engineering, University of Wyoming, Laramie, Wyoming
82071

µSchool of Energy Resources, University
of Wyoming, Laramie, Wyoming 82071

The
objective of this research is to find an optimal ratio of rare earth elements
(RE), lanthanum (La) and cerium (Ce), as promoters of Co-based Fischer-Tropsch
synthesis (FTS) to achieve maximal diesel yield.  Synthesized rare-earth promoted catalysts were
characterized with Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM),
X-ray diffraction (XRD) and hydrogen temperature programmed reduction (H₂-TPR).
The effects of La/Ce molar ratio on the FTS performance of silica gel supported
cobalt based catalysts were investigated in a fixed bed reactor at the
temperature of 220 and 240 °C. The evaluation tests show that the
catalysts promoted by composited rare-earth (CRE) with appropriate molar ratio
La to Co have better FTS performance than unpromoted and individual rare-earth
(IRE) promoted catalysts. The results show that
the CRE promoted FTS catalysts are promising. The CO conversion is increased
significantly and the selectivity of methane and C₂-C₄ is
decreased while the selectivity of long chain hydrocarbons is greatly increased
(C₅⁺ increased from 70.36% to 80.25% at 220 °C
and from 69.94 % to 78.02 % at 240 °C, respectively). Among
all CRE modified catalysts, based on the result of distribution of C₁₂-C₁₈
(weight % of hydrocarbons), Co-1La2Ce/S.G (n RE: n Co = 0.1 and n La: n Ce = 1:
2) is proven as a highly efficient catalyst for production of diesel rich
synthetic oil from coal-derived syngas.