(48f) Fischer-Tropsch Synthesis: Impact of Sulfur on Iron Catalysts

The impact of sulfur on an iron catalyst appears to depend upon the reactor and temperature utilized for the synthesis. In a fixed bed reactor there appears to be general agreement that the upper portion of the catalyst bed acts as a getter, allowing the rest of the catalyst to act in a relatively sulfur-free environment, until the bed is saturated with sulfur. Data for high-temperature fluidized bed operations are less clear and the finer details may be masked, or at least impacted, by the much greater carbon deposition. For the low-temperature slurry synthesis, the situation is even more complex. There are reports of activity enhancement for low concentrations of sulfur prior to attaining a sufficient sulfur loading to cause the activity to decline. Others do not report the activity increase. The data for low temperature synthesis with increased activity for low sulfur levels will be reviewed.