Injection of hydrogenous gases into the blast furnace tuyeres for reducing CO₂ emissions: a review

Abstract

Transitioning to alternative fuels like natural gas (NG), coke oven gas (COG), or hydrogen presents a viable path to reduce carbon emissions in blast furnace ironmaking. A review of industrial practices and simulations reveals significant variabilities in estimating the impacts of hydrogenous gases' tuyere injection on the blast furnace operation due to a lack of representative industrial-scale experiments and diverse modeling approaches. NG is effective yet regionally constrained, while COG, although beneficial for improving efficiency and reducing emissions, has limited availability for injection. High coke replacement efficiency ranks NG superior for emission reduction. Meanwhile, COG and cold hydrogen offer similar CO₂ reduction potentials, with carbonaceous gases offsetting COG's higher coke replacement ratio. Preheating hydrogen can further improve its coke replacement efficacy, achieving the greatest reduction in CO₂ emissions. Hydrogen injection has yet to reach economic viability, but technological progress, scaling up, and evolving carbon legislation could alter this, prompting steel producers worldwide to advance hydrogen injection techniques in blast furnaces.