A comprehensive kinetics model of Fischer–Tropsch synthesis over an industrial Fe–Mn catalyst Original Research Article

A comprehensive Fischer–Tropsch synthesis (FTS) kinetics model including the hydrocarbon and oxygenate formation reactions as well as water gas shift (WGS) reaction over an Fe–Mn catalyst is developed in a continuous spinning basket reactor. On the basis of CH2 insertion alkyl mechanism, the kinetics expressions for paraffins, olefins, alcohols and acids are derived. Kinetics calculation results indicate that the formation of paraffins, olefins, alcohols and acids over the Fe–Mn catalyst are parallel competitive reactions. Reasonable and strict analysis in mathematics is given to interpret the results which the comprehensive kinetics model cannot predict the olefin/hydrocarbon ratio well though the olefin readsorption and secondary reactions are involved in the kinetics model. Oxygenates might readsorb over the catalyst surface and take part into the corresponding secondary reactions (chain growth and hydrogenation to the corresponding hydrocarbons), which leads to the exponentially decrease of the experimental alcohol/hydrocarbon and acid/hydrocarbon ratios with the increase of carbon number.