Emission characteristics of a novel low NOx burner fueled by hydrogen-rich mixtures with methane

摘要

The use of hydrogen-rich fuels may be challenging for burner designers due to unique properties of hydrogen comparedto conventional fuels such as natural gas. Burner retrofit may be required to use hydrogen-enriched fuels in combustionsystems that are designed for natural gas combustion. This study aimed to experimentally investigate NOx emissionsfrom a novel low NOx burner fueled by methane-hydrogen mixtures. The burner was tested in a cylindrical combustionchamber at atmospheric pressure. Burner thermal load of 25 kW (LHV) and air-fuel equivalence ratio of 1.15 weremaintained throughout the experimental campaign. The influence of burner design parameters on NOx emissions wastested for various fuel compositions using a statistically cognizant experimental design. The study revealed that shiftingthe burner head upstream can deliver NOx emission reduction. In contrast, supplying fuel to the burner through secondaryfuel ports increases NOx emissions, particularly when the burner head is shifted upstream. The lowest predictedNOx emissions from the burner are below 9 ppmvd at 3% of O2 and 14 ppmvd at 3% of O2 for 5% and 30% massfraction of hydrogen in the fuel, respectively.