9th International Conference on Modeling and Simulation of Metallurgical Processes in Steelmaking - STEELSIM2021

Increasing interest in the direct reduction of Iron has revived investigations on the kinetics of gaseous reduction of iron oxides. Despite extensive investigations on the reduction of iron oxides with pure hydrogen or with syngas, the development of a generic reduction mechanism of iron oxides is still lacking. The conventional shrinking core model hardly distinguish between transport processes and reaction processes, leading to biases in the kinetic model. In the present study, a porous solid model, which solves mass balances of the individual gas species and solid ones assuming a spherical symmetry is used for developing a heterogeneous kinetic mechanism accounting for different iron oxides (Fe2O3, Fe3O4, FeO). It also accounts for carbon accumulation and iron carbide (Fe3C) formation at lower temperature to model phenomena like carbon-deposition and incomplete reduction of iron oxide using CO/-H2 mixtures. The present study will attempt to fit a single mechanism on multiple experimental data sets of single pellet reduction with syngas of varying content up to pure hydrogen from the literature. Finally, the effects of gas composition, flow rates, temperature and pellet characteristics such as porosity, tortuosity, diameter factor on the reduction of iron oxide will be investigated.