Competitive Models and Mechanisms of Gasification Reactions on Hydrogen-Rich Smelting Process of Blast Furnace

Abstract

Blast furnace hydrogen-rich smelting effectively reduces CO₂ emissions; however, the introduction of H₂ generates H₂O within the blast furnace, which influences the gasification reaction of coke. This study investigates the gasification reaction rates of coke in CO₂/H₂O single gas and CO₂–H₂O mixed gas atmospheres, employing an analog circuit method to construct the corresponding model. The results indicate that external gas diffusion is the rate-limiting step in the coke gasification process. In a CO₂–H₂O–N₂ (40–20–40%) mixed gas environment, the coke gasification rate is lower than the sum of the rates observed in CO₂–N₂ (40–60%) and H₂O–N₂ (20–80%) atmospheres, suggesting a competitive interaction between CO₂ and H₂O in the gasification reaction of coke. Six different methods were employed to calculate the gasification reaction rates of coke in CO₂/H₂O single gases and CO₂–H₂O mixed gases, and the results reveal that method 6 most accurately elucidates their interaction. Additionally, the effect of H₂O in the CO₂–H₂O–N₂ mixture on coke gasification is more pronounced than that of CO₂. Compared to coke gasification with only H₂O, the CO₂–H₂O mixed gas promotes the conversion of amorphous carbon, reduces the consumption of aromatics, and increases the microcrystalline size.