EFFECT OF PERIODIC DOSING OF ETHENE IN THE FISCHER-TROPSCH SYNTHESIS

An experimental study of the influence of periodic dosing of ethene during the Fischer-Tropsch synthesis reaction over a cobalt catalyst at 473 K and 110 kPa revealed that it is possible to enhance both the rate of reaction and the selectivity of reaction by means of high frequency periodic addition of ethene to the feed mixture. In previous investigations of reaction systems under periodic operation, selectivity was usually improved at the expense of catalyst activity. For the first time, improvements in both selectivity and activity have been observed. Increases of up to 100% in the olefin/paraffin mole ratio were recorded under the conditions which produced the greatest rate and selectivity improvements. The rate-controlling step(s) in the Fischer-Tropsch synthesis would appear to be unchanged by periodic operation.