Simulation Study, Techno-Economic, and Environmental Assessment of Hydrogen-Based DRI Production for Sustainable Steel Industry

The iron and steel industry is a major contributor to global carbon emissions, necessitating an urgent transition to sustainable production technologies. This study investigates the techno-economic feasibility and environmental impact of a hydrogen-based direct reduced iron (DRI) production process via multi-stage fluidized bed reactors, focusing on the ironmaking stage and excluding downstream steelmaking routes. A comprehensive process model was developed incorporating reduction kinetics and validated against experimental data, achieving high predictive accuracy with an R² exceeding 0.999. The environmental assessment reveals that the renewable energy-based scenario achieves specific CO₂ equivalent (CO₂e) emissions of 36.8 kg per ton of hematite, corresponding to a 98.1% reduction compared to the conventional blast furnace baseline. Although the initial techno-economic analysis indicates a higher unit production cost of 636.83 USD/ton due to renewable energy costs, the sensitivity analysis demonstrates that cost competitiveness against the natural gas-based scenario is secured at a carbon price threshold of 1.44 USD/tCO₂e. Furthermore, under the 2018 average Korea Emission Trading System price of 20.66 USD/tCO₂e, the cost deceases to 589.76 USD/ton, offering a 7.39% economic advantage over the grid-based alternative. These findings indicate that green hydrogen integration and carbon pricing can bridge economic gaps, supporting economically viable low-carbon DRI production.