CFD Modeling of a Thermally Efficient Modular Reactor for Fischer–Tropsch Synthesis: Determination of the Optimal Size for Each Module

A modular multichannel reaction module with microchannel-based coolant channels was considered, and a computational fluid dynamics (CFD) model was developed to describe the hydrodynamic behavior of the module. Reaction rates for the lumped chain length distribution of hydrocarbon products generated by the Fischer–Tropsch synthesis reaction were proposed, and the developed kinetic and CFD models were shown to satisfactorily fit the experimental data under different production rates. High heat transfer rates resulting from the use of microchannel-based cooling channel maintained the temperature peak below 10 °C, and simulation results with increased size of the catalytic bed and absence of inert materials showed that the high heat of reactions could be efficiently removed over entire catalytic beds, preventing the creation of local hot spots, which are usually observed in conventional fixed bed reactors. In addition, the efficient use of thermal energy could guarantee that methane selectivity, which needs to be maintained as low as possible, was close to approximately 10% under all conditions, while the selectivity of the desired hydrocarbons (C5+) slightly increased with increasing feed flow rates.