Mercury Oxidization in Dielectric Barrier Discharge Plasma System

The pronounced volatility of elemental mercury (Hg 0 ) and some of its compounds, coupled with their extreme toxicity, makes these substances extremely hazardous. Conversion of Hg 0 to HgO would significantly enhance mercury removal from flue gases. This investigation is focused on studying the effect of some of the constituents such as O 2, H 2 O, CO 2, and NO x present in flue gases on elemental mercury oxidation in a dielectric barrier discharge (DBD) reactor. The results show that Hg vapors (6 ppbv) in a stream of 0.1% O 2 and N 2 are effectively oxidized at the energy density of up to 114 J/L. Hg conversion of over 80% is achieved when present in a gas mixture of 8% O 2, 2% H 2 O, and 10% CO 2 in N 2 balance. The presence of NO x enhanced mercury oxidation in the DBD reactor. The oxidation chemistry is discussed. Studies show that Hg can be simultaneously removed along with the other two major pollutants, NO x and SO 2, in one DBD reactor followed by a wet scrubber system. This avoids the need of three techniques for the removal of major gaseous pollutants from coal-fired power plants.