Numerical Analysis of a Cleaner Blast Furnace Practice Based on Combined Hydrogen Fuel Gas and Pulverized Charcoal Injection

Abstract

In the pursuit of carbon-neutral steelmaking, alternative reducing agents such as hydrogen and bio-based fuels have gained prominence as substitutes for metallurgical coke in blast furnace operation. This study employs a detailed six-phase multicomponent mathematical model to evaluate the effects of combined hydrogen-rich gas and pulverized charcoal (PCH) injection on furnace behavior and decarbonization potential. The model solves the conservation equations of mass, momentum, energy, and species, incorporating complex gas–solid interactions throughout the shaft. Results reveal that a 25% reduction in coke rate can be achieved without compromising furnace thermal stability or permeability. The high reactivity of hydrogen, coupled with PCH combustion near the tuyeres, maintains raceway temperatures above 2100 °C and preserves the cohesive zone structure. Gas flow remains homogeneous, and solid burden descent is unaffected, ensuring consistent process conditions. A transition from CO- to H₂-dominated reduction is observed, particularly for the FeO→Fe step, leading to more distributed reaction zones and improved thermal efficiency. These shifts reduce solution loss reactions and support a stable operation even under reduced coke conditions. Environmentally, total CO₂ emissions decrease, with fossil-derived emissions reduced by 45.9%. The findings validate the technical viability of hydrogen and biochar co-injection as an effective low-carbon strategy for existing blast furnaces, offering a promising route toward sustainable ironmaking aligned with global emissions targets.