Thermodynamics analysis of innovative carbon-negative systems for direct reduction of iron ore via chemical looping technology

To mitigate the significant carbon footprint of traditional ironmaking, this study evaluates four advanced direct reduced iron (DRI) systems powered primarily by biomass. These innovative systems employ chemical looping technology and CO2 capture techniques to produce carbon-negative iron. Detailed system modeling, optimization, and thermodynamic evaluations have been performed to analyze exergy flows, energy consumption composition and carbon emissions. Results show that chemical looping gasification requires substantial power input for CO2 removal, whereas systems based on chemical looping hydrogen production (CLHP) naturally capture CO2, significantly reducing energy consumption. Without CH4-assisted carburization, CLHP-DRI systems demand more energy due to the reverse water-gas shift reaction. Thus, CH4-assisted carburization is crucial for maximizing the benefits of CLHP. Compared to the traditional MIDREX process, the CH4-assisted CLHP-DRI system achieves a 7.6 % reduction in energy consumption. Environmentally, these systems offer a carbon-negative potential between 0.836 and 1.079 t-CO2/t-DRI, demonstrating substantial promise for sustainable iron production.