Fast long-term simulations of hot, reacting, moving particle beds with a melting zone

Hot, reacting, moving particle beds as found in blast furnaces comprise a wide range of spatial and temporal scales. We present an approach that combines models for granular motion, interfacial mass, momentum and heat transfer as well as heterogeneous multi-step reactions efficiently. Although they correspond to vastly different scales, long-term investigations built upon data from discrete-element simulations become feasible. The strategy was first applied to 0.5 kg hematite reducing to iron under a CO atmosphere, where the most relevant reaction parameters were obtained from optimization towards experimental data. Then, we studied a 3D, full-scale blast furnace and its approach towards the thermo-chemical steady state over the course of 20 h.The framework may be easily extended, which will allow for realistic simulations of moving particle beds over process-relevant durations. It has the potential to create digital twins so that different reactor types can be optimized and novel designs explored.