Evaluation of kinetic models for Fischer-Tropsch cobalt catalysts in a plug flow reactor

In order to do a good and realistic design of a Gas-to-Liquid (GTL) plant, it is necessary to have kinetic models that correctly capture major variations of reaction rates and selectivities subject to changes in process parameters. In this study, a review of published kinetic rate models is done and twelve of them are analyzed based on different criteria, such as their behaviour at high conversions, high water partial pressure, sensitivity to added water, selectivity to C5+ products, etc. The rate models are implemented in a plug flow reactor model. Both fixed bed and microchannel reactors can quite accurately be represented by such a model. Here, the main purpose is to see the kinetic effects with changing composition along the reactor. In order to predict the product distribution, we have proposed our own chain growth model and fitted parameters to experimental data from Yang et al. (2016). The chain growth model includes the effect of water and predicts the C5+ and methane selectivities quite well.