Numerical investigation of hydrogen-rich gas and pulverized coal injection in the raceway of a blast furnace with lower carbon emissions.

• NG and COG consumption is computed based on BF mass and heat balance and simulated. • The raceway state is compared as the coal ratio is same and NG and COG are used. • NG injection has more effect on coal reaction behaviors compared with COG. The application of hydrogen-rich gas in the pulverized coal injection technology represents a precious solution to mitigate carbon emissions. In this research, a three-dimensional physical model has been constructed based on the actual dimensions of the gas lance, coal lance, blowpipe, tuyere and raceway of a prominent blast furnace in China. A comparative analysis of the tuyere and raceway status, along with the coal combustion behaviors, is conducted using numerical simulation method after the injection volume of the two hydrogen-rich gases changes. The simulation outcomes demonstrate that the introduction of natural gas into the blast furnace has a comparatively larger influence on the temperature within the raceway, in contrast to the injection of coke oven gas, leading to a more noticeable temperature reduction. Additionally, the average temperature at the tuyere outlet is about 20 K higher with coke oven gas injection compared to natural gas injection under equivalent coal ratios. Furthermore, the burnout of particles is lower in the case of natural gas injection compared to coke oven gas injection. When the injection rates of natural gas and coke oven gas increase, and the coal ratio decreases from 170 kg/t to 140 kg/t, the burnout of coal powder decreases from 68.11% to 64.12% and 64.73%, respectively. The impact of injecting natural gas on coal powder combustion is more pronounced. The research offers a theoretical guide for advancing the mixed application of natural gas, coke oven gas, and particles in the blast furnace, serving as a valuable guide for practical implementation. [ABSTRACT FROM AUTHOR]