Performance evaluation of non-thermal plasma injection for elemental mercury oxidation in a simulated flue gas

•The use of non-thermal plasma injection approach to oxidize Hg0 in simulated flue gas at 110°C was studied.•A high Hg0 oxidation efficiency was observed in the mixed flue gas that included O2, H2O, SO2, NO and HCl.•Chemical and physical processes (e.g., ozone, N2 metastable states and UV-light) contributed to Hg0 oxidation.•Mercury species mainly existed in the form of HgO(s) adhering to the suspended aerosols in the gas-phase. The use of non-thermal plasma (NTP) injection approach to oxidize elemental mercury (Hg0) in simulated flue gas at 110°C was studied, where a surface discharge plasma reactor (SDPR) inserted in the simulated flue duct was used to generate and inject active species into the flue gas. Approximately 81% of the Hg0 was oxidized and 20.5μgkJ−1 of energy yield was obtained at a rate of 3.9JL−1. A maximal Hg0 oxidation efficiency was found with a change in the NTP injection air flow rate. A high Hg0 oxidation efficiency was observed in the mixed flue gas that included O2, H2O, SO2, NO and HCl. Chemical and physical processes (e.g., ozone, N2 metastable states and UV-light) were found to contribute to Hg0 oxidation, with ozone playing a dominant role. The deposited mercury species on the internal surface of the flue duct was analyzed using X-ray photoelectron spectroscopy (XPS) and electronic probe microanalysis (EPMA), and the deposit was identified as HgO. The mercury species is thought to primarily exist in the form of HgO(s) by adhering to the suspended aerosols in the gas-phase.