The olefin to paraffin ratio as a function of catalyst particle size in Fischer–Tropsch synthesis by iron catalyst

•Preparing iron nanoparticles by the reverse microemulsion.•The effect of particle size on O/P hydrocarbons ratio was evaluated.•Size dependent O/P ratio was developed.

The dependence of olefins to paraffins ratio on catalyst particle size in Fischer–Tropsch synthesis by iron catalyst is studied. A series of catalyst with different particle size is prepared by microemulsion method. The experimental results showed the Fischer–Tropsch reaction rates passed from a maximum by decreasing the catalyst particle size. Studies on secondary reactions can also be observed from the dependency of the O/P ratio on chain length. The ratio of olefins to paraffins depends on catalyst type, structure and the reaction conditions. The results show that the olefin/paraffin ratio decreased with decreasing the catalyst particle size. Using the experimental results we concluded that the O/P ratio depended on solubility impact of produced hydrocarbons (vapor–liquid equilibrium) and surface phenomena of the catalysts.