A Study of Flameless Combustion Behavior of Pulverized Coal Preheated by Circulating Fluidized Bed

Paper from the AFRC 2015 conference titled A Study of Flameless Combustion Behavior of Pulverized Coal Preheated by Circulating Fluidized Bed.A new technology based on pulverized coal preheated by CFB was proposed, which could achieve stable flameless combustion, high combustion efficiency, and low NOX emission of pulverized coal. Experiments were conducted on a bench-scale rig of pulverized coal combustion preheated by CFB to study the flameless combustion behavior. Typical coals were used in the experiments for comparison and to investigate the fuel flexibility of the technology. The results show that the fuel flexibility is well for bituminous coal, anthracite and Semi-coke. The flameless combustion is very stable and the temperature of the camber is uniform for the three coals. What's more, the average combustion temperature is 1200°C, which is much lower than that of traditional combustion technology. Fuel preheating is also effective to improve combustion efficiency and decrease NOX emissions especially for anthracite. The combustion efficiencies are 99%, 94.1% and 92.3% for bituminous coal, anthracite and Semi-coke. The NOX emissions are 352.34 mg/m3, 232.30 mg/m3 and 458.35 mg/m3 for bituminous coal, anthracite and Semi-coke