Conversion of nitrogen oxides in N-2:O-2:CO2 and N-2:O-2:CO2:NO2 mixtures subjected to a DC corona discharge

This paper concerns the influence of a direct current (dc) corona discharge on production and reduction of NO, NO2 and N2O in N-2:O-2:CO2 and N-2:O-2:CO2:NO2 mixtures. The corona discharge was generated in a needle-to-plate reactor. The positively polarized electrode consisted of 7 needles. The grounded electrode was a stainless steel plate. The gas flow sate through the reactor was varied from 28 to 110 cm(3)/s. The time-averaged discharge current ranged from 0 to 6 mA. It was found that in the N-2:O-2:CO2 mixture the corona discharge produced NO, NO2 and N2O. In the N-2:O-2:CO2:NO2 mixture the reduction of NO2 was between 6-56%, depending on the concentration of O-2, gas flow rate and corona discharge current. The NO2 reduction was accompanied by production of NO and N2O. The results show that efficient reduction of nitrogen oxides by a corona discharge cannot be expected in the mixtures containing N-2 and O-2 if reducing additives are not employed.