The urgent need for the decarbonization of steel metallurgy in the face of climate change causes a paradigm shift, eventually leading to a transformation of well-established industry processes. This transformation, for example towards a clean hydrogen-based direct reduction of iron, requires knowledge about the interdependencies of all process parameters—something that physically sound process modeling with high extrapolative power can offer.

We show how the combined use of thermodynamic and kinetic process modeling can simulate heat and mass transport in industrial iron ore pellets exposed to a reducing gas stream with varying chemical composition in a shaft furnace. To achieve this, we employ a one-dimensional micro-reaction model with explicit time stepping, which takes into account kinetics and thermodynamics of the reduction and gas-gas reactions as well as diffusion, providing a detailed understanding of the system's dynamic behavior.

Our approach enables the integration and optimization of specific input parameters, such as kinetic parameters, properties of the iron oxide pellets, and gas input streams, and hence supports finding pathways to the decarbonization of the steel industry.