Feasibility study of the diluted combustion in a semi-industrial boiler at low temperatures

The aim of this work is to assess the technical feasibility and highlight the specific problem of
application of diluted (or mild) combustion in a medium scale boiler by direct gas injection. The
main difficulty is due to the high geometrical confinement and heat losses of a typical boiler
combustion chamber, which prevents from getting the minimum level of reactants dilution and
temperature needed to reach mild combustion regime. Last year, a preliminary CFD study was
performed to select a jet burner and secondary gas injector able to generate sufficient dilution and temperature of the air and gas jets before they meet in the combustion chamber of the boiler. In this work, the optimization of the position and the diameter of the gas injector has been performed. Finally, the boundary conditions and the parameters of the combustion model have been investigated.