Ammonia has attracted considerable attention as a carbon-free fuel for reducing carbon emissions. However, its low reactivity and flame propagation speed limit its direct application to conventional combustion systems. Blast furnace gas (BFG) and coke oven gas (COG) are major by-product gases generated in the steel industry, and their co-combustion with ammonia can provide an effective approach for reducing carbon emissions while utilizing existing fuel resources. In this study, the combustion characteristics of BFG/COG/NH₃ mixtures were experimentally investigated using a lab-scale laminar flow burner. Three BFG/COG blending conditions (BC10, BC20, and BC30) with ammonia addition ratios of 10–30% were investigated at global equivalence ratios ranging from 0.6 to 1.2. Direct flame images were captured using a high-speed camera to analyze flame structure. The flame length increased with increasing equivalence ratio due to reduced oxidizer availability. Despite the higher reactivity of COG, the flame length also increased with increasing COG fraction, which was attributed to the increased fuel velocity and enhanced axial convective transport in the diffusion flame. Gas emissions, including NO_x, N₂O, NH₃, and CO₂, were analyzed using an FT-IR gas analyzer.
 

Ammonia, Blast furnace gas, Coke oven gas, Direct flame image, Combustion