Development of a porous solid model for DRI applications

Abstract

The Direct Reduction (DR) of iron ore pellets with syngas or hydrogen is a promising technology to reduce the emissions of iron making. The conversion rate of single iron-ore pellets to iron has been extensively investigated. In most of these works a shrinking core model is employed to reproduce the experimental observations. However, this model presents an inherent bias by assuming a sharp separation between a fully converted region and a fully unreacted one. In the present study, we propose an improved porous solid model. This model solves for the mass balances of the individual gas species and the solid ones assuming spherical symmetry. The governing equations, the main algorithm, and validation cases will be presented. The open-source suite Cantera was integrated in the model. This allows the use of heterogeneous reaction mechanisms and facilitates chemical kinetics calculations. The present model also offers a wide flexibility to incorporate complex phenomena such as porosity change or carbon deposition. Another advantage of our new approach is its easy integration in multidimensional computations. In this way, the reliability of the kinetic and transport models is insured when used in multidimensional CFD-calculations.