Oxidative Removal of Elemental Mercury in Flue Gas by DBD Discharge Plasma

Abstract

Oxidation of gas phase elemental mercury (Hg0) in the simulated flue gas by DBD plasma under atmospheric pressure and ambient temperature (298 K) was conducted. Experimental results indicated that the oxidative efficiency of Hg0 increased with O2 content, the residence time of flue gas in reactor and the applied voltage. The oxidation efficiency of Hg0 reached over 96% under the applied voltage of 11 kV and the residence time of 0.24 s when the O2 content in flue gas was 20%, and the corresponding energy efficiency was at about 14.1 μg kJ-1. It was noted that the oxidation efficiency of Hg0 could still reach 80% when the O2 content in flue gas was only 4% (near the actual O2 content in flue gas of coal-fired boilers). The experimental results indicated that DBD plasma was one of the efficient technologies for purification of Hg0 vapor industrial flue gas.