Kinetics of Fischer–Tropsch synthesis on titania-supported cobalt

Rate data have been obtained for CO hydrogenation on a well-characterized 11.7% Co/TiO₂ catalyst in a differential fixed bed reactor at 20 atm, 180–240°C, and 5% conversion over a range of reactant partial pressures. The resulting kinetic parameters can be used to model precisely and accurately the kinetics of this reaction within this range of conditions. Turnover frequencies and rate constants determined from this study are in very good to excellent agreement with those obtained in previous studies of other cobalt catalysts, when the data are normalized to the same conditions of temperature and partial pressures of the reactants. Based on this comparison CO conversion and the partial pressure of product water apparently have little effect on specific rate per catalytic site. The data of this study are fitted fairly well by a simple power law expression of the form −r_CO=kP_H2^0.74P_CO^−0.24, where k=5.1×10⁻³ s⁻¹ at 200°C, P=10 atm, and H₂/CO=2/1; however, they are best fitted by a simple Langmuir–Hinshelwood (LH) rate form −r_CO=aP_H2^0.74P_CO/(1+bP_CO)² similar to that proposed by Yates and Satterfield.