Numerical investigation of a hydrogen-rich injection strategy to enhance pulverized coal reactivity in the blast furnace raceway

Hydrogen injection through the tuyere can accelerate iron ore reduction and reduce carbon emissions, but may also lower raceway temperature and suppress pulverized coal (PC) burnout. The effects of a hydrogen-rich coaxial injection structure with radial gas discharge on raceway characteristics and PC combustion were investigated using a 3D CFD gas-powder flow model. Results show that both natural gas (NG) and coke oven gas (COG) injections disperse the PC plume and enhance PC reactions. As NG injection increased, the furnace temperature decreased by 6.54 K per 10 m³/tHM, while the PC burnout rate first increased and then declined, reaching 74.81% at 20 m³/tHM. Compared with NG, COG produced a stronger dispersion effect. The furnace temperature decreased by 6.88 K per 20 m³/tHM, and the PC burnout peaked at 78.35% at 80 m³/tHM. The hydrogen-rich injection cases with this configuration achieved higher PC burnout than the case with PC injection alone.