脉冲介质阻挡放电条件下NO／O2／N2／Hg^0体系反应动力学模拟

KINETIC SIMULATION OF NO/N_2/O_2/Hg^0 STREAMER UNDER DIELECTRIC BARRIER DISCHARGE

利用低温等离子体净化烟气中NO_x和Hg是一种极具前景的技术,本文对脉冲介质阻挡放电条件下的NO/O_2/N_2/Hg^0体系建立了反应动力学模型,对高能电子参与N_2、O_2和H_2O电离解速率常数采用碰撞反应截面方法求取,模拟预测了活性自由基元(O、OH)、和Hg^0等组分在反应器内随时间的变化规律。模拟结果表明:脉冲介质阻挡放电可以有效地脱除烟气中的NO,并促进单质汞的氧化;脉冲电源特性对脱除效率有明显的影响,电源纳秒级脉冲峰宽时间越长,电源脉冲放电频率越高,NO净化及单质汞的氧化效率越好。

The removal of nitrogen oxide and elemental mercury in simulated flue gas with the non- thermal plasma is prospective approach in future. In this paper, a kinetic model is developed to characterize the reactions taking place in a system of NO/O2/N2/Hg^0 under the dielectric barrier discharge and the electron-impact reaction rate constant of the ionization by electron-molecule collisions is obtained by collision reaction cross section method. The concentrations of various atoms, free radicals（O, OH）, NOx and Hg species are predicted according to the resident time in plasma reactor. The sinmlation results show that the dielectric barrier discharge removes nitric oxide effectively and prompt the oxidation of elemental mercury. The imapct of the characteristics of the power supply on the removal process is obvious. Longer pluse time the effect of removal of nitric oxide and oxidation and higher frequency of power supply is, the better of elemental mercury are.