Effect of Na/Ca/Fe on Slagging Behavior of Zhundong Coal During Combustion Process

Combustion experiments were conducted for Zhundong coal in a drop tube furnace, where ash particles were collected at different flue gas temperatures by a sampling probe in un-cooled mode, so as to analyze the status of different inorganic components in the flue gas before slagging, as well as to obtain the combination mode of ash particles. Results show that at the temperature of 1000℃, the ash particles containing sodium silicates, sodium aluminosilicates, and calcium sulphates keep in molten state, which impact and adhere on the tube wall; with the rise of slag layer thickness, the surface temperature increases, leading to the formation of molten film on the slag layer to further capture other ash particles; Fe species are fluxing agents, which may react with Si, Al, Mg, Na and Ca system to form the low temperature eutectic; when particles rich in Fe₂O₃ impact the molten deposit surface, a new layer of slag would be created due to the reduced melting point of deposit surface caused by the fluxing action of Fe₂O₃.