Fischer-Tropsch synthesis: Attempt to tune FTS and WGS by alkali promoting of iron catalysts

Venkat Ramana Rao Pendyala, Gary Jacobs, Janet C. Mohandas, Mingsheng Luo, Wenping Ma, Muthu Kumaran Gnanamani, Burtron H. Davis

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

The effect of water on the performance of alkali-promoted, precipitated Fe catalysts was investigated during Fischer-Tropsch (FT) synthesis in a continuously stirred tank reactor. In these studies, the added water (5-25 mol%) replaced an equivalent amount of inert gas so that all other reaction conditions remained the same before, during and after water addition. The externally added water had a positive effect on the CO conversion for all the alkali-promoted, precipitated iron catalysts. The impact of the added water is to increase the rate of the water-gas shift (WGS) reaction with up to 10-15 mol% added water, and then leveling off for further increases in the amount of water added to the feed gas. Increasing the water amount in the feed gas caused the fraction of CO converted into hydrocarbons to decrease and both the WGS activity and the oxygenate selectivity to increase. Common for all the alkali promoted iron catalysts was a decrease in C5+ selectivity and an increase in the methane selectivity with increasing amounts of water up to 10-15 mol%; with further increases of water, the C5+ selectivity increases and methane selectivity decreases. Methane selectivity is directly correlated to the CO conversion and H2/CO ratio inside the reactor.

Original languageEnglish
Pages (from-to)131-139
Number of pages9
JournalApplied Catalysis A: General
Volume389
Issue number1-2
DOIs
StatePublished - Dec 1 2010

Bibliographical note

Funding Information:
This work was supported by the Commonwealth of Kentucky and a grant from the Kentucky Governor's Office of Energy Policy (KY – GOEP) Energy Research and Development Program entitled “Towards understanding how alkali promoters alleviate CO 2 production and enhance chain growth probability over iron Fischer–Tropsch synthesis catalysts.”

Keywords

  • Alkali
  • Fischer-Tropsch synthesis
  • Iron catalysts
  • Lithium
  • Potassium
  • Rubidium
  • Water effect

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology

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