Investigation into the Ignition Behaviours of Pulverized Coals and Coal Blends in a Drop Tube Furnace using Flame Monitoring Techniques

This paper presents experimental investigations into the ignition behaviors of pulverized coals and coal blends in a drop tube furnace using a flame monitoring system. Seven different ranks of coals and coal blends of different mixing proportion were tested. Characteristic parameters including relative ignition temperature, maximum ignition points, oscillation frequency, fluctuation ratio and combustion dynamic energy were determined from the flame monitoring system. The ignition behaviours of the coals are established by combining the parameters. Results demonstrate that the parameters are suitable for distinguishing ignition behaviors from homogeneous, hetero-homogeneous to heterogeneous in the ignition section of a drop tube furnace. The ignition behaviors of a coal blend are found to have similar characteristics as the coal of higher volatile matter in the blend and depend on its proportion in the blend. The results from this study are used to predict the operation of a coal fired power plant in terms of fuel selection, fuel blending, and flame stability.