Kinetics study for fischer-tropsch synthesis over cobalt catalyst by kinetic monte-carlo simulation

Abstract

Kinetic Monte-Carlo simulation was utilized to study the kinetic behaviors of C₁ and C₂ formation in the Fischer-Tropsch synthesis over the cobalt surface by varying reaction conditions. Two reaction models: the carbide mechanism and the CO insertion mechanism were applied to this simulation. The production rates and fractional coverages of each adsorbed species could be calculated under the steady state. Moreover, the combination between carbide and CO insertion mechanism was also studied to suggest the possibility of each reaction mechanism, and compared the results with the reported experimental results under the same conditions. It was ob-served that the C–C bond formation was mainly performed through the insertion of adsorbed CO into a metal–methyl bond. Based on the CO insertion mechanism, the results obviously presented that the process conditions essentially influenced on the reactivity and selectivity of the reaction. The system exhibited non-reactive regions at the temperature below 463 K and the H₂/CO feed molar ratio lower than 1.1. In the steady reactive states, the surface is predominantly covered with adsorbed H and CO, and played an important role in the hydrocarbon chain growth.