TY - JOUR
T1 - Fischer-tropsch synthesis
T2 - Effect of potassium on activity and selectivity for oxide and carbide fe catalysts
AU - Gnanamani, Muthu Kumaran
AU - Hamdeh, Hussein H.
AU - Shafer, Wilson D.
AU - Sparks, Dennis E.
AU - Davis, Burtron H.
PY - 2013/11
Y1 - 2013/11
N2 - The effect of potassium on oxides and carbides of iron for Fischer-Tropsch synthesis (FTS) was investigated by pretreating Fe3O4 and K-promoted Fe catalysts with different gases (H2/H2O and CO). A freshly activated sample and catalysts that were recovered from the CSTR before, during and after FT synthesis were characterized ex situ using Mössbauer spectroscopy. Iron carbide is found to be active for both FT and water gas shift (WGS) reactions. After H2/H2O activation, all three catalysts (Fe3O4, low α-Fe, and high α-Fe) exhibit a steady but low FT activity for a period of FT synthesis. However, both FT and WGS activity for Fe3O4 and low α-Fe catalysts were greatly improved after CO activation. In contrast, the high potassium containing catalyst (high α-Fe) did not show any further improvement in activity after CO activation. The difference in FT and WGS activity observed after pretreatment conditions using these catalysts may be associated to the amount of potassium and conversely the iron carbide present in the catalysts. Graphical Abstract: [Figure not available: see fulltext.]
AB - The effect of potassium on oxides and carbides of iron for Fischer-Tropsch synthesis (FTS) was investigated by pretreating Fe3O4 and K-promoted Fe catalysts with different gases (H2/H2O and CO). A freshly activated sample and catalysts that were recovered from the CSTR before, during and after FT synthesis were characterized ex situ using Mössbauer spectroscopy. Iron carbide is found to be active for both FT and water gas shift (WGS) reactions. After H2/H2O activation, all three catalysts (Fe3O4, low α-Fe, and high α-Fe) exhibit a steady but low FT activity for a period of FT synthesis. However, both FT and WGS activity for Fe3O4 and low α-Fe catalysts were greatly improved after CO activation. In contrast, the high potassium containing catalyst (high α-Fe) did not show any further improvement in activity after CO activation. The difference in FT and WGS activity observed after pretreatment conditions using these catalysts may be associated to the amount of potassium and conversely the iron carbide present in the catalysts. Graphical Abstract: [Figure not available: see fulltext.]
KW - Fischer-Tropsch synthesis
KW - Iron carbide
KW - Magnetite
KW - Oxygenates
KW - Potassium
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U2 - 10.1007/s10562-013-1110-7
DO - 10.1007/s10562-013-1110-7
M3 - Article
AN - SCOPUS:84890078755
SN - 1011-372X
VL - 143
SP - 1123
EP - 1131
JO - Catalysis Letters
JF - Catalysis Letters
IS - 11
ER -