In the present work, fixed bed reduction experiments were conducted at 1173 K over a range of H2/CO ratios from 0.8 to 2.0 and subsequently modelled numerically. The model consists of two one-dimensional, isothermal and time dependent models. The gas–solid reactions were kinetically modelled using a modified shrinking core approach, and the equations were solved using the commercial software COMSOL Multiphysics®. The simulation results agree with thermal gravity experimental data with an average difference of 2.5%. A sensitivity analysis was conducted using the numerical model to establish the optimum operational conditions. The effects of the reducing gas ratio and flow rate, pellet radius and porosity, and the total bed height on the overall degree of reduction were also investigated.
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