Effect of the Air Preheating Temperature on Flameless Combustion of Low Calorific, Alternative Fuels

Flameless oxidation is an efficient technology applied to industrial furnaces to have high efficiency, low NOx emission and energy saving by air preheating. This experimental study shows the results of tests performed on a 30kW laboratory-scale furnace using alternative fuels and methane. Three different air preheating temperatures have been tested, showing the possibility to have stable flameless combustion and low NOx emission without using high air temperatures, even for low calorific fuels. Analysis and comparisons are carried out using thermocouples data, images of OH radicals by UV Camera, and CO, NOx, CO2, O2 content measurements by dedicated gas analyzers.