Kinetic Study of Fischer–Tropsch Synthesis Using a Co/CNTs Catalyst

Abstract

The intrinsic kinetics of the Fischer–Tropsch synthesis reaction in the conversion of synthesis gas into liquid hydrocarbons in a spinning basket reactor over a cobalt catalyst supported on carbon nanotubes were studied. The catalyst was synthesised by the impregnation wetness technique and the reactor tests were done at 215–245 °C, 20 bar, a H2/CO molar ratio of 2 and a gas hourly space velocity of 2.4–12 Nl gcat−1 h−1. To develop an appropriate kinetic model for syngas consumption, five different mechanisms were considered as possibilities for the Fischer–Tropsch reaction, each with a rate-determining step. The rate equations obtained were based on the Langmuir–Hinshelwood–Hougen–Watson model and statistical analyses were used for comparing the resulting values. The activation energies were found to be limited within the range 89–145 kJ mol−1 and the adsorption constants of hydrogen and carbon monoxide were in the range −32 to −76 kJ mol−1 and −13 to −64 kJ mol−1 respectively.