Effects of hydrogen addition to methane on the flame structure and CO emissions in atmospheric burners

Hydrogen addition to methane will have an important role to reach a fully developed hydrogen economy. The effects of this addition on the flame structure and CO emissions were evaluated in two different atmospheric burners. Four fuels with the following composition were used: 100%CH4, 2%H2+98%CH4, 6%H2+94%CH4 and 15%H2+85%CH4. In a single-port atmospheric burner, a decreasing trend in the height of the blue cone with hydrogen addition was determined. The increase in the laminar burning velocity was identified as the main effect on the behavior of this parameter. In a drilled-port atmospheric burner, a significant reduction in CO emissions with hydrogen addition was achieved under two operating conditions: (1) keeping the primary air ratio constant and (2) keeping the primary air ratio and the thermal input constant. The results obtained were consistent with previous experimental studies. This reduction is attributed to a higher concentration of OH radicals as a result of hydrogen addition.