Research On Simultaneous Conversion Of NO And SO₂ In Flue Gas By Pulsed Discharge

People are paying more and more attention to flue gas cleaning technologies in coal-fired power plants, which are one of the most important sources of air pollution. De-NO_X and De-SO₂ technologies have been developed and used widely. Recently, fine particle emission also attracts people's attention. Electric agglomeration is becoming a research hotspot as an effective way to control fine particle emission. Because of particularity of pulsed power supply, it has not only good charging effect but also good oxidation effect of NO and SO₂. Hence, combined with solution adsorption, it is possible to integrate fine particle,NO and SO₂ emission control in one pulsed discharge reactor simultaneously. It reduces the cost of flue gas cleaning greatly.Firstly, De-NO_X and De-SO₂ technologies especially the removal of NO and SO₂ by pulsed corona discharge were included. And then the experimental system for simultaneous conversion of NO and SO₂ was briefly introduced.In this article, the kinetics of reaction process was analyzed and the experiments under two kinds of conditions were performed as below: (1): The conversion of NO and SO₂ by pulsed corona discharge when there was only NO or SO₂ in flue gas. The relations between NO/SO₂ conversion efficiencies and pulsed discharge parameters including pulse peak voltage, pulse frequency, electrode number, residence time, air humidity, initial concentration, fly ash addition were investigated separately. (2) The conversion of NO and SO₂ by pulsed discharge when they were added in flue gas simultaneously. On the basis of experiment (1), the influence relations between NO and SO₂ on conversion efficiencies were also investigated. The results indicate that NO and SO₂ conversion efficiencies increase with increasing pulse peak voltage, pulse frequency, electrode number and residence time. And NO and SO₂ conversion efficiencies decrease with increasing initial concentration. High air humidity improves SO₂ conversion efficiency, but restrains NO conversion. Low concentration of fly ash addition improves NO and SO₂ conversion, however, with high concentration, the fly ash restrains pulsed discharge, which results in lower NO and SO₂ conversion. NO has bad effect on SO₂ conversion, however, SO₂ almost has no effect on NO conversion. Under our system, when both NO and SO₂ initial concentrations are approximately 300ppm, power consumptions of 18W·h/m³ and 9.3 W·h/m³ achieve NO and SO₂ conversion efficiencies of 50%,65% and 40%,50%, respectively.