Chemical Engineering & Technology, Vol.37, No.6, 964-972, 2014
Intrinsic and Effective Kinetics of Cobalt-Catalyzed Fischer-Tropsch Synthesis in View of a Power-to-Liquid Process Based on Renewable Energy
The production of liquid hydrocarbons based on CO2 and renewable H2 is a multi-step process consisting of water electrolysis, reverse water-gas shift, and Fischer-Tropsch synthesis (FTS). The syngas will then also contain CO2 and probably sometimes H2O, too. Therefore, the kinetics of FTS on a commercial cobalt catalyst was studied with syngas containing CO, CO2, H2, and H2O. The intrinsic kinetic parameters as well as the influence of pore diffusion (technical particles) were determined. CO2 and H2O showed only negligible or minor influence on the reaction rate. The intrinsic kinetic parameters of the rate of CO consumption were evaluated using a Langmuir-Hinshelwood (LH) approach. The effectiveness factor describing diffusion limitations was calculated by two different Thiele moduli. The first one was derived by a simplified pseudo first-order approach, the second one by the LH approach. Only the latter, more complex model is in good agreement with the experimental results.
Keywords:Cobalt catalyst;Fischer-Tropsch synthesis;Mass transfer;Power-to-liquid process;Renewable energy