The effects of the hydrogen addition on the HCN profiles in fuel-rich-premixed, burner-stabilized C1-C3 alkane flames

► HCN mole fractions measured in 1-D flames using probe sampling and IR absorption. ► Hydrogen addition modestly affects HCN mole fractions in CH4, C2H6 and C3H8 flames. ► The peak HCN fraction decreases by less than 20% upon hydrogen addition. ► Chemical mechanisms predict the HCN profiles reasonably well. ► Comparison with NO profiles shows only HCN conversion to NO downstream.