Dynamic modeling of a direct reduced iron shaft furnace to enable pathways towards decarbonized steel production

Steel production can be decarbonized by utilizing direct reduced iron (DRI) shaft furnaces that use green hydrogen or a mixture of green hydrogen and natural-gas-derived syngas. To further the implementation of these steel decarbonization methods, the development of a physics-based dynamic model of a DRI shaft furnace is presented and its applications are shown through transient case studies. The model is validated with industrial data and has mean average errors of 0.3 wt% for outlet solids composition and 1.2 mol% for outlet gas composition. Transient results are presented for a furnace shifting from syngas to a mix of syngas and green hydrogen as well as a furnace using only hydrogen that varies hydrogen flow and the inlet reducing gas temperature. The model can simulate 4-hour transient tests in under 3 min on a modest computer, highlighting its future use for control algorithm development, plant-scale simulations, and online, real-time, model predictions.