Numerical Analysis of Low-carbon Blast Furnace Operations by Coke Oven and Hydrogen Gases Injection in COURSE50 Experimental Blast Furnace

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.