Effect of water on the iron-catalyzed Fischer-Tropsch synthesis

The addition of water vapor to dry synthesis gas to comprise as much as 27 mol % of the feed composition decreased catalyst activity, but the effect was completely reversible upon removal of the water vapor. Reversibility was not complete with water addition to comprise 42 mol % of feed. Water vapor decreased methane selectivity, increased oxygenate selectivity, and increased the rate of the water gas shift. However, these effects did not correlate with the relative Fe/sub 5/C/sub 2/, Fe/sub 3/O/sub 4/, and Fe content of the bulk catalyst as determined by Mossvauer spectroscopy, although the Fe/sub 5/C/sub 2/ content did not change greatly. Molecular weight distribution of the C/sub 3/-C/sub 7/ products was not affected by water.