Effect of H2O and SO2 on the distribution characteristics of trace elements in particulate matter at high temperature under oxy-fuel combustion

The purpose of this work is to clarify the effects of high concentrations of H2O and SO2 on the generation of particulate matter (PM) and the distribution characteristics of trace elements in PM under oxy-fuel coal combustion. The experiments were carried out in a high temperature drop tube furnace which was set as 1500 °C, and the Dekati Gravimetric Impactor (DGI) sampling system was applied to collect the PM at the outlet of the furnace (sampling temperature, 135 °C). The results indicate that, compared to air combustion, oxy-fuel combustion significantly decreases the amount of PM and the total mass of trace elements in PM, but enhances the concentrations of trace elements in PM, except Mn. Under oxy-fuel combustion, similar conclusions about the formation of PM and migration of trace elements can be drawn, with the decreasing oxygen concentration. There is no significant difference in the amount of PM with the SO2 addition, but the total mass of trace elements or the concentrations of trace elements in PM decreases. Steam enhances the amount of PM and the total mass of trace elements in PM to a great extent but decreases the concentrations of trace elements in PM.