Modeling of Catalytic Fixed-Bed Reactors for Fuels Production by Fischer-Tropsch Synthesis

A comprehensive review of the various studies reported in the literature to date on the mathematical modeling of fixed-bed reactors for the production of fuels by the Fischer-Tropsch synthesis (FTS) was carried out. It is quite clear that most of the proposed models are based on a set of assumptions that allow their wide simplification by reducing the models into forms of low complexity, due to the fact that in most cases the effects of phase equilibrium are neglected, and relatively simple Fischer-Tropsch kinetics of the power law type are used. In addition, most of the proposed modeling schemes neglect the effects of resistances to gas-liquid and liquid-solid mass transfer. On the other hand, few reports consider the energy effects under the consideration of a nonisothermal operation assuming a plug-flow behavior and a gas-liquid system. A generalized model of a fixed-bed FTS reactor is proposed which takes into account all the mass and heat transfer phenomena, as well as hydrodynamics and vapor-liquid equilibrium (VLE), based on the information given in the literature. It is evident that for fixed-bed reactors for fuel production using Fischer-Tropsch technology, there is little experimental information for validation and a need to explore different types of reactor models, such as reactor models under a trickle-flow regime considering the effects of phase distribution and dispersion under transient-state conditions.