Removal of $\hbox {NO}_{x}$ , $\hbox {SO}_{2}$ , and Hg From Simulated Flue Gas by Plasma - Absor

The simultaneous removal of NOx, SO₂, and Hg from simulated flue gas by a plasma-absorption hybrid system was investigated. In the nonthermal plasma reactor, NO could be effectively oxidized to NO₂. However, Hg⁰ oxidation was significantly restrained since NO concentration and its reactivity with O₃ are much higher than those of Hg⁰. In the absorber, SO₂ and NO₂ were absorbed by (NH₄)₂ SO₃ solution, in which the S(IV) ions (SO₃^2- and HSO₃^-) were found to be dominant for NO₂ absorption. The S(IV) ions were significantly oxidized during the absorption, causing an increase in NO₂ concentration with operating time. However, the addition of S₂O₃^2- inhibited the S(IV) oxidation and promoted the removal of NO₂. With a followed electric mist eliminator, the NH₃ slipped from the absorber can be captured, and Hg⁰ was efficiently oxidized, which can be further removed by water absorption.