Thermodynamic Model of MIDREX Ironmaking Process Using FactSageTM and Macro Facility

Abstract

In the present work, a thermodynamic model for the MIDREX direct reduction process has been developed and validated with industrial data. The model conceptualizes the process as a counter current reactor consisting of multiple conceptual reactors. The fraction of gas being utilized in each zone is estimated using the kinetic considerations of the process. The overall kinetic effect involving the effect of mass transfer control in the gas, and solid product, along with chemical reactions at the interface of the unreacted solid surface are considered. The model is used to predict the carbon content, production rate and metallization for the given set of input variables. The model predictions are in good agreement with industry reported data. The model thus developed for the MIDREX process, can be used as a guiding tool to the process and can be used to study the effect of variation in the operating parameters (like inlet and cooling gas composition, temperature, volumetric flow rates) on the process output parameters (productivity, metallization and carbon content). The same model can also be used to study the effect of other replacements like coke oven gas, and natural gas in the reduction process with the objective of improvement in the production rate without compromise regarding metallization. © 2023, The Minerals, Metals & Materials Society and ASM International.