Fxiperimental Research On The Removal Of Nitrogen Oxides By Dielectric Barrier Discharge Plasma

Selective catalytic reduction (SCR) is the widely used flue gas NOx emission control measures. However, the problems of SCR appear to be the catalyst poisoning, narrow temperature operation band, and ammonia leakage. Dielectric barrier discharge(DBD) is one of the most promising flue gas denitrification technology, presently the new combined DBD-SCR technologyis considered as a better solution. This paper used a coaxial cylindrical dielectric barrier discharge reactor to generate Non-thermal plasma to research the NOx removal effect in different conditions.The experiment of removal of NO using dielectric barrier discharge plasmas was carried out to study the influence of acetylene concentration, oxygen, relative humidity and temperature on the removal. Results show that oxidation of NO is strengthened by the addition of C2H2, and the removal efficiency of NO increases as more C2H2is added. The concentration of oxygen has no effect on NO removal. The addition of H2O at room temperature constrainedthe discharge in DBD reactor, and the decrease of the generation of electrons lead to the reduction of NO removal rate. But the effect will be weakened with the increasing of energy density; the removal efficiency of NO can reach a same level. Meanwhile, the removal product of NO was mainly HNO3by adding water. when temperature increased, the dissociation of C2H2, N2and O2is enhanced, the reaction rates which involved HO2, CH2and C2H radicals increased, thus increasing the efficiency of NO and NOx.Since the active ingredient produted by discharge extremely short life, the two-stage DBD-followed-by-catalyst method has no better effect on NO removal. Theoreticl study proved catalyst filled in DBD reactor enhanced the plasma discharge. The experiment using catalyst-pellet-filled DBD plasma was carried out to study the NO removal effect in different background atomsphere. The results showed that:in NO/N2/O2and NO/N2/O2/C2H4system, the NO removal efficiency in the process of catalyst-pellet-filled DBD plasma was significantly higher than that in the process of DBD alone.Furthermore,DBD filled withFe2O3/γ-Al2O3catalyst had a better performance on NO removal than that filled with γ-Al2O3, the porous structure of catalyst obviously promoted NO adsorption and C2H4dissociation.