Numerical analysis of low-carbon blast furnace operations by coke oven and hydrogen gases injection in COURSE50 experimental blast furnace

Abstract

The CO₂ Ultimate Reduction System for Cool Earth 50 (COURSE50) project has been implemented in Japan to develop low-carbon operations of blast furnaces using hydrogen-based reductant gases. A series of experiments were conducted on an experimental blast furnace constructed at Nippon Steel's East Nippon Works in Kimitsu area. In these experiments, coke oven gas (COG) and H₂ gas at room temperature were injected from tuyeres. The maximum injection volume of the hydrogen-based reductants of COG at 190 Nm³/ton-hot metal (tHM) and H₂ gas at 315 Nm³/tHM resulted in carbon reduction rates of approximately 5.7% and 16%, respectively. In this study, we present summaries of the experimental trials and their numerical analysis for the above two cases using the three-dimensional mathematical blast furnace model. Furthermore, a numerical prediction was conducted to assess the impact of larger volumes of COG and H₂ injections than those of the trials that actually conducted. Accordingly, it was estimated that achieving a carbon reduction rate greater than 20% through hydrogen-based reductant gas injection at room temperature would be challenging. This finding indicates that compensation for input heat not derived from carbon combustion is essential to achieve further low-carbon blast furnace operation using hydrogen-based reductant gases.