气相组分对非热等离子体氧化气相元素汞的影响

采用线串齿轮-管式正极性流光放电反应器产生非热等离子体,考察了放电等离子体参与下烟气中各组分对元素汞氧化的影响.结果表明, CO2的加入和高浓度的NO导致作用于汞的活性粒子减少,从而阻碍元素汞的氧化.在等离子体作用下,部分CO2会与活性粒子作用而转化为CO.加入NO浓度为670mg/m3,电压升高到9.5kV时,仅有37%的元素汞被氧化. SO2的加入能促进元素汞的氧化,而且伴随SO2的氧化和白色HgSO4和Hg2SO4的生成,电压升高到10kV时,反应器出口基本检测不到元素汞. H2O和HCI也具有促进元素汞氧化的作用,这可能是因为氧化性· OH形成得到促进和反应气氛中存在C1-离子.部分元素汞和氧化态汞在荷电后会被等离子体反应器捕集,因此等离子体作用后,气相总汞浓度显著降低.

Effects of Gas Compositions on the Oxidation of Gas Phase Elementary Mercury by Non-thermal Plasma

The effects of flue gas compositions such as NO, SO2, CO, H2O on elementary mercury oxidation by non-thermal plasma induced by positive streamer discharge were experimentally investigated by using a link tooth wheel-cylinder reactor. The results showed that the oxidation of elementary mercury decreased in the presence of CO2 and NO, which was attributed to the reduction of number of the active radicals reacted with elementary mercury. Adding 670 mg/m3 NO, only 37% elementary mercury was oxidized when the voltage was 9.5 kV. And CO was produced because of the reaction between CO2 and active radicals. The presence of SO2 resulted in an increase of elementary mercury oxidation, and white HgSO4 and Hg2SO4 were formed, little elementary mercury was detected at the outlet of the reactor when the voltage was 10 kV. Similarly, H2O and HCI promoted the oxidation of elementary mercury, which may be due to the formation of oxidative *OH and the presence of Cl- ions. The total mercury concentration dramatically decreased after the discharge reactor because the charging mercury was collected.