Residual gases with low heating values resulting from steel production plants are presently poorly valorised, although they represent an important energetic reservoir. These gases exhibit specific combustion characteristics as compared to conventional gases. These untypical properties make necessary transposing the combustion techniques which are presently used. The proposed project aims at identifying, by means of experimental and numerical techniques, technological solutions for exploiting in an optimal way these gases in steel reheating furnaces, over a large spectrum of operating conditions. Experimental databases will be acquired at laboratory and semi-industrial scales. In parallel, fundamental numerical studies will allow characterising the interactions between chemistry and turbulence for these gases. This will feed the development of a micro-physical model, which will be validated and implemented in a three-dimensional simulation code used for designing and optimising industrial installations. The obtained numerical tool, which will be able to characterise in detail the interactions between chemistry, turbulence and radiation will be used by the industrial partner for identifying technological evolutions of burners and industrial furnaces, with the final objective of minimising pollutant and greenhouse gas emissions.