Pulverized Fuel Combustion in a Turbulent Round Jet Burner

Experiments were performed in the near-field of a combustion-driven, coaxial round jet burner to investigate the turbulent combustion of solid fuel particles. Pulverized coal of varying volatile content and size, ranging from submicron to 149 j*m, was employed as a fuel in this study. The flow configuration consisted of a central high-speed jet, comprising coal and air, exhausting into a coaxial shroud jet of hot combustion products. Concentration data obtained at distances of up to 20 initial jet diameters from the inlet to the combustor suggest that, for the conditions examined here, reaction of the solid fuel is confined to the interface between the two jets. Particles in excess of approximately 50 fim in diameter did not appear to react in significant quantity within the present range of particle residence times. Particle size data provide some evidence of a preferential outward dispersion or consumption of fine particulates. A well-defined optimum value of solid fuel loading at which combustion proceeds most vigorously was determined. This optimum value was only weakly influenced by coal size, injection velocity, and fuel volatile content.