Kinetic model of Fischer-Tropsch synthesis in a slurry reactor on Co-Re/Al2O3 catalyst

Abstract

A kinetic model for Fischer-Tropsch synthesis is derived using a Langmuir-Hinshelwood-Hougen-Watson approach. Experiments were conducted over 25% Co/0.48% Re/Al 2 O 3 catalyst in a 1 L slurry reactor over a range of operating conditions (T = 478, 493, 503 K; P = 1.5, 2.5 MPa; H 2 /CO = 1.4, 2.1; WHSV = 1.0-22.5 NL/(g cat ·h)). Rate equations were based on the elementary reactions corresponding to a form of well-known carbide mechanism. The 1-olefin desorption rate constant was assumed to be a function of carbon number due to the effect of weak interaction of the hydrocarbon chain with the catalyst surface. Values of estimated activation energies are in good agreement with those reported previously in the literature. The kinetic model was able to correctly predict all of the major product distribution characteristics, including the increase in chain growth probability and decrease in olefin-to-paraffin ratio with carbon number, as well as formation rates of methane and ethylene. © 2012 American Chemical Society.