Iron ore reduction predicted by a discrete approach

Abstract

The iron making blast furnace (BF) is a continuously operating shaft furnace that primarily performs the reduction of ore, pellets or sinter as a granular material through a reducing gas. Despite large numbers of probing and measuring points and sophisticated measuring and control systems installed at today’s blast furnaces the reactor is still considered a black box. Numerical models based on a continuous description neglect entirely the characteristics of a packed bed composed of individual particles of different size and composition. In order to compensate for these deficiencies and to capture the nature a packed or moving bed as an ensemble of individual particles undergoing thermal conversion a model framework for a single particle is required. Therefore, the objective is to describe the thermodynamic state including chemical reactions for a single particle. For this purpose, one-dimensional and transient differential conservation equations for mass, momentum and energy are solved. It yields the internal distribution of temperature, species and reaction progress according to the phase diagram for iron reduction. Predicted results were compared to experimental data at different temperatures and good agreement was achieved. Thus, this approach constitutes the basis for an more advanced model of the blast furnace that is represented by a moving bed of individual iron-bearing particles to be reduced. It is intended to apply the current model to regions of the shaft of a blast furnace, so that a more accurate modelling approach is achieved leading to a deeper understanding of the relevant processes.