Energy and Exergy Analysis of Hydrogen-Based Fluidized Bed Direct Reduction towards Efficient Fossil-Free Ironmaking

Hydrogen-based fluidized bed direct reduction (H-FBDR) is an important and promising route for fossil-free ironmaking. In this study, to achieve the optimal operation state of energy use exergy efficiency, influences metallization process ratios H2 injected on flows in H-FBDR are studied. The results show that thermodynamically designed two-stage (first: Fe2O3→FeO; second: FeO→Fe) requires a smaller quantity than other processes. According mass, energy, balance analyses, variations consumption, destruction, energy/exergy losses overall system, iron ore preheater (F1), reactor system (R), heat exchanger (E), gas (F2) with different (η) derived. total rise increasing η, sharp increases observed from η = 1.3 1.8. efficiencies (φ) can be ranked as φR > φE φF1 ≈ φF2, destruction components F1 F2 mainly caused by combustion reaction, whereas physical dominates R E. performances F1, E, degrade 1.0 1.8, significant degradation arises when exceeds 1.3. Thus, considering thermodynamic losses, ratio should set below Notably, although loss 2 GJ/h at 1.3, only 360 MJ/h, which recycled gases component E occupy 320 900 MJ/h. Therefore, improving performance units, particularly F2, recovering optimizing process.