Investigating the production of liquid fuels from synthesis gas (CO + H2) in a bench-scale packed-bed reactor based on Fe–Cu–La/SiO2 catalyst: experimental and CFD modeling

A computational fluid dynamic (CFD) and experimental study of Fischer–Tropsch Synthesis (FTS) process in a fixed-bed reactor is presented. The reactor was a 1.2 cm diameter and 80 cm length steel tube in which ceramic particles were employed to dilute the catalyst bed and thus prevent the emergence of hot spot in it. An axisymmetric CFD model with an optimized mesh of 22,016 square cells was developed to model hydrodynamics, chemical reaction, and heat and mass transfer in the reactor. Thermodynamic non-ideal behavior of the gas mixture was modeled using Peng–Robinson equation of state. Kinetic models for FTS and water–gas-shift reaction rates based on Langmuir–Hinshelwood type for each of the species were employed. Good agreement was achieved between the bench experimental data and the model. Performing reactions inside packed-bed reactor due to high pressure and temperature is very difficult and expensive, and CFD simulations are considered as numerical experiments in many cases. A sensitivity analysis was run to find the effect of temperature, pressure, GHSV and H2/CO ratio on the reactor performance. It was concluded that the obtained results from CFD analysis give precise guidelines for further studies on optimization of FTS fixed-bed reactor performance.