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

We demonstrate that our one-dimensional micro-reaction model which simulates reaction kinetics, heat and mass transport can predict how porosity and convergence degree of industrial iron ore pellets exposed to a reducing gas stream are affected by process parameters like the reduction gas composition and materials properties like the pellet diameter. Our model with explicit time stepping accounts for gas-gas reactions as well as diffusion, providing a detailed understanding of the system's dynamic behavior and the chemical, thermophysical and transport processes in the pellets.

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 hydrogen’s integration into the industrial landscape for reducing the carbon footprint of the steel industry.