Mild combustion: Process features and technological constrains

The Mild Combustion is a relatively novel combustion technique characterize d by both an elevated temperature of reactants and an adiabatic flame tempe rature not higher than 1600K. These features are the results of several tec hnological demands coming form different application fields. The main advantages derived by Mild Combustion concern both the combustion process itself and its applications. In the former case the pollution reduc tion, the increase of efficiency process and fuel flexibility has to be con sidered whereas the latter one is principally related to heat treatment pro cess and wall confinement. In this paper, characteristics of Mild Combustion are discussed with partic ular regards towards the aspects of plant design. A general classification of the processes, where initial and adiabatic temperature values are differ ent from characteristic ones of classical combustion system, is given. This classification leads to a definition of Mild Combustion process as a direc t consequence of technological evolution and practical constrains, especial ly related to environmental problems. In this sense, the high temperature o f reactants and the low adiabatic temperature, principally obtained using e xhausts for both heat recovery and dilution, can not be considered independ ently. Application of Mild Combustion in practical systems infers the use o f particular solutions because of high temperature of reactants involved. I n the final part of the paper, specific solutions utilized in a laboratory mild combustor are presented.