Influence of gas components on the oxidation of elemental mercury by positive pulsed corona discharge

Abstract

This study examines the effect of flue gas components on the oxidation of gaseous elemental mercury (Hg 0 ) to HgO and HgCl 2 via pulsed corona discharge (PCD), where the reaction temperature was set to 908C and the gas stream consisting of 3% H 2 O and 10% O 2 in N 2 was mixed with 45 mg m 73 Hg 0 , 108 ppm NO x , 80 ppm HCl, 200 ppm SO 2 and 470 ppm NH 3 . It has been observed that O 2 and HCl components in the gas stream act as oxidizing precursors through the generation of oxidizing species (O, O 3 , Cl and Cl 2 ) in the PCD process. The presence of NO directly hampers Hg 0 oxidation to HgO due to preferential reaction of NO with O and O 3 . In contrast, the presence of SO 2 indirectly influences the oxidation of Hg 0 to HgCl 2 through the fast reaction of SO 2 with OH radical, resulting in consuming OH radicals which are partially responsible for the formation of chlorine species, i.e. Cl and Cl 2 . It has been also found that NH 3 component significantly hinders the oxidation of Hg 0 to HgCl 2 through the fast acidbase reaction with HCl.

Oxidation of Elemental Mercury by Active Species Generated From a Surface Dielectric Barrier Discharge Plasma Reactor

“…The reaction rate coefficient of NO with O 3 (1.8 9 10 -14 cm 3 molecules -1 s -1 ) (Reaction 13) [29] is much faster than that of (10.5 ± 0.65) 9 10 -19 cm 3 molecules -1 s -1 [30] for Hg 0 reacting with O 3 , implying that the O 3 can rapidly react with NO. Therefore, O 3 will be preferentially exhausted, Hg 0 oxidation efficiency markedly reduced, being in agreement with the results obtained in previous studies [31][32][33]. The concentration of SO 2 was varied to study effect of SO 2 on the Hg 0 oxidation (Fig.…”

Elemental mercury oxidation in an electrostatic precipitator enhanced with in situ soft X-ray irradiation

“…Dielectric barrier discharge (DBD), a type of AC corona discharge, has been well studied as a Hg 0 oxidation technique (Chen et al, 2006;Jeong and Jurng, 2007;Byun et al, 2008Byun et al, , 2011aByun et al, , 2011bKo et al, 2008c;Lin et al, 2010;Wang et al, 2010;Jiang et al, 2012). Similarly, DC corona discharge (Liang et al, 2002;Wang et al, 2009Wang et al, , 2011aWang et al, , 2013a and pulsed corona discharge (Liang et al, 1998;Ko et al, 2008aKo et al, , 2008bXu et al, 2009) have also been used to oxidize Hg 0 . Notably, corona discharge has additional beneficial effects other than Hg 0 oxidation.…”

Development of Catalyst-Sorbents for Simultaneous Removal of SO2From Flue Gas by Low Temperature Ozone Oxidation

“…Water-insoluble NO and elemental mercury Hg 0 can be homogeneously oxidized by O 3 molecules into water soluble species like NO 2 , NO 3 , N 2 O 5 and oxidized mercury Hg 2+ , etc. (Hu et al, 2004;Ko et al, 2008).…”