Influence of forced cycling on the fischer‐tropsch synthesis. Part I. Response to feed concentration step‐changes

The response of the Fisher‐Tropsch synthesis to composition step‐change was studied as part of a larger study on the influence of forced feed composition cycling on the product distribution from this synthesis reaction. Using a promoted iron catalyst, studies were conducted at 384 kPa total pressure in a fixed‐bed differential reactor held at 246°C by means of an oil bath. It was determined that the reaction rate was not influenced by mass or heat transfer effects. The maxima in the curves of steady state rate versus feed composition for various products occurred considerably above the stoichiometric ratio for each product olefin. This fact suggested that the rate was probably controlled by hydrogen adsorption in the initiation sequence. Support for this interpretation was also found from the response of the rates of production of light hydrocarbons (C 2 to C 5 ) to the step‐changes in feed concentration.