Thermal and Performance Analysis Flameless Combustion Process in a High Temperature Industrial Furnace Using Computational Fluid Dynamics

Heat treatment furnaces play an important role in refinery and petrochemical systems. The emission of a huge amount of environmental pollutants such as nitrogen oxides (NOx) and carbon dioxide (CO2), along with the cost of repairs and periodic overhauls have given more attention to the optimization of the furnaces. Flameless combustion as a newly emerging process, with features such as reducing emissions of pollutant gases, uniform distribution of temperature profile along with reducing thermal stresses, and noise pollution in the torch, promising to change the conventional combustion systems and move them toward emission, operational, and maintenance costs reduction. In this study, the burner made by Sholeh-Sanat Company was investigated using the computational fluid dynamics under pre-heating conditions and oxygen concentrations of 3 and 6%. The furnace performance was considered in steady flameless conditions with eddy-dissipation concept (EDC). Flameless combustion characteristics were obtained in the torch and compared to conventional combustion; moreover, the temperature peaks were eliminated, and the temperature profile became more uniform. Also, in the 6% state, the mass fraction of nitrogen oxides and carbon dioxide compounds were observed to be about 400 and 3000 times decreasing respectively. Working under 3% mode, more uniform temperature profile and less nitrogen oxides were observed.