Numerical investigation of the impact of injecting coke oven gas on raceway evolution in an ironmaking blast furnace

Using coke oven gas (COG) as a cost-effective alternative fuel in the ironmaking blast furnace has gained considerable attention. However, its dynamic impact on the raceway's shape and size remains to be determined. This study presents a comprehensive investigation using a 3D transient Computational Fluid Dynamics (CFD) model to study and compare the effects of injecting COG and reformed COG on the dynamic raceways of blast furnaces. The complex multiphase flow and thermochemical behaviours associated with the combustion of COG and reformed COG in the dynamic raceway are quantified and compared in terms of the evolution of the raceway profile, gas temperature, and species distribution when using different injection rates. The results indicate that injecting COG leads to forming a larger raceway size by 5 % compared to reformed COG. The gas temperature along the tuyere centerline exhibits higher values by 2 %-7 %, while the molar fraction of CO and CO2 increases by 30 % and 15 %, respectively. Moreover, the molar fraction of O2 and H2 shows a 3 % increase under similar injection rates. These findings help to understand the potential of reformed COG injection to further reduce carbon emissions compared to COG injection in blast furnaces.

Automated summary

This study investigates the dynamic impact of injecting coke oven gas (COG) and reformed COG on the raceway's size and shape in ironmaking blast furnaces. The results show that injecting COG leads to a larger raceway size and higher gas temperature and CO and CO2 concentrations compared to reformed COG.