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 axi-symmetric 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.