Oxidation and Removal of NO From Flue Gas by DC Corona Discharge Combined With Alkaline Absorption

The effects of discharge polarity, discharge electrode configuration, and O
₂
/CO
₂
ratio on NO oxidation by nonthermal plasma (NTP) and NO
_x
removal by the combination of NTP and alkaline absorption in simulated flue gas were investigated in a combined system of a wire-cylinder plasma reactor and a bubble absorber. The preoxidation of NO by dc corona discharge is effective in promoting the NO
_x
absorption. Both the NO oxidation efficiency and the NO
_x
removal efficiency increase with the increase of applied voltage. The positive dc discharge exhibits much higher O
₃
formation and NO oxidation performances than the negative one. The increase of the discharge zone length and tooth slice number significantly influences the energy density in the plasma reactor and improves the NO oxidation efficiency for a fixed applied voltage. Increasing the O
₂
/ CO
₂
ratio in the simulated flue gas obviously enhances the NO oxidation and NO
_x
removal.