Impact of Bosh Gas Volume on the Competitive Interaction between CO and H<sub>2</sub> Reduction Reactions and Carbon-Saving Potential in the Top Gas Recycling Blast Furnace

The blast furnace ironmaking process has become a critical link for carbon emission reduction in steelmaking technology. As a novel low-carbon blast furnace process characterized by low coke rate, low carbon emissions, and high smelting efficiency, the top gas recycling blast furnace (TGR-BF) holds significant potential for carbon reduction within this process. In this study, a multi-fluid model was employed to investigate the smelting state, carbon-saving potential, and interactions between reducing gases in the TGR-BF under different bosh gas volume (BGV). When the BGV increased from 3681 Nm3/min to 4081 Nm3/min, the hot metal production rose from 5299.5 t/d to 5676.4 t/d, the reduction contribution rate of CO for FeO increased from 34.96% to 37.82% while that of H2 for FeO decreased from 65.04% to 62.18%. The coke consumption for raceway combustion increased from 93.81 kg/tHM to 99.85 kg/tHM, coke consumption for direct reduction reactions rose from 20.8 kg/tHM to 22.8 kg/tHM, coke comsumptiom in carbon solution loss reactions decreased from 26.8 kg/tHM to 24.07 kg/tHM, the Global Warming Potential (GWP100) increased from 2.39×10-10 to 2.59×10-9, and the total environmental impact increased from 6.10×10-10 to 1.09×10-9.