Diluted combustion with high air pre-heating: Experimental characterization of laboratory furnace by means of advanced diagnostics

Heat recovery systems allow preheating of combustion air up to temperature of 1300 degreesC to obtain high efficiency and to save a large amount of fuel. Nevertheless in conventional burner/furnace designs: high temperature of combustion air shows unacceptable NOx emission levels. The solution to this problem is to dilute the reactants before combustion in order to flatten the temperature peaks. The combustion process that occurs under these conditions is characterised by the absence of a stabilised flame anchored to the burner and by a more uniform temperature distribution inside the combustion chamber. This diluted combustion or MILD combustion (MILD as : M ($) under bar oderate and I ($) under bar ntense L ($) under bar ow oxygen D ($) under bar ilution) is a very promising new combustion technology, because it reconciles best efficiency and low emissions. Object of this report is to present the in-progress research program, related to the MILD combustion, carried out at ENEA, and the main aspects of a national program on this technology that ENEA is organising together with other scientific and industrial Italian participants aimed at developing this new combustion technology for application in industrial and civil processes.