Fischer-tropsch synthesis: Effect of potassium on activity and selectivity for oxide and carbide fe catalysts

Muthu Kumaran Gnanamani, Hussein H. Hamdeh, Wilson D. Shafer, Dennis E. Sparks, Burtron H. Davis

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

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.]

Original languageEnglish
Pages (from-to)1123-1131
Number of pages9
JournalCatalysis Letters
Volume143
Issue number11
DOIs
StatePublished - Nov 2013

Keywords

  • Fischer-Tropsch synthesis
  • Iron carbide
  • Magnetite
  • Oxygenates
  • Potassium

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry

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