介质阻挡放电中气体成分对NO_x脱除的影响

Effect of gas composition on NO_x removal in dielectric barrier discharge reactor

利用介质阻挡放电(DBD)产生低温等离子体进行烟气的脱硝实验,研究了在乙烯存在的条件下,温度和其他烟气成分对NOx脱除率的影响。结果表明:随着温度的升高,NO脱除速率增快;模拟烟气中加入CO2,在能量密度较低时,CO2作为电负性分子会降低自由基的生成,导致NO的脱除率降低,随着能量密度的升高,CO2对NO脱除的影响减小;模拟烟气中加入水后可以产生更多的OH、HO2等自由基,促进NO的氧化;SO2的加入会与自由基O反应,使初始反应中O与C2H4的反应速率减弱,从而影响了NO的氧化速率,但O3、HO2等强氧化自由基会优先与NO反应,因此SO2的加入不会影响NO最终的脱除率。

The experiment for removal of NOxin flue gas by non-thermal plasma generated in dielectric barrier discharge（DBD）was conducted to study the influence of temperature and gas composition of gas containing-ethylene on the removal.The results show that rate of NO removal is accelerated by increase of temperature.Under lower energy density,addition of electronegative molecule CO2into simulation gas leads to efficiency reduction of NO removal because of decrease of radical generated,but the effect will be weakened with increasing energy density.The water addition in simulation gas can result in formation of more free radicals such as OH and HO2which can promote oxidation of NO.However,if SO2is also added which can react with O radical,on one hand,the reaction rate of O and C2H4in the initial stage can be reduced,which makes NO oxidation decrease.On the other hand,free radicals O3and HO2with strong oxidation ability can react with NO prior to SO2.So,addition of SO2has no influence on NO removal.