Development and testing of flameless burner fed by NG/H2 mix

The reduction of CO2 emissions from combustion equipment is the main solution to reduce the concentration of greenhouse gases in atmosphere and then the development of new combustion systems based on carbon free fuels is a priority for combustion research. Hydrogen is one of the most promising fuels, if produced by renewable sources it can guarantee zero-CO2 emissions, but attention must be paid about NOx emissions, which can increase in case of use of hydrogen. A research activity including CFD analysis and experimental tests allows verifying the proper working of a 2.0 MW industrial flameless burner fed with a gaseous mixture composed by 30% of hydrogen and 70% of methane (volumetric basis). CFD results fully agree with experimental data; the burner can operate with both natural gas or mixture without any modification on the combustion process and NOx emissions. At a furnace temperature 1250 °C, combustion air temperature 520 °C, NOx emissions are below 80 mg/Nm3@3%O2. In case of working with stable and anchored flame NOx emissions increase as expected. The activity result allows individuating flameless combustion as one of the most suitable techniques for the use of hydrogen in iron and steel industry.