RESIDENCE TIME EFFECTS ON THE NOX REMOVAL EFFICIENCY IN TWO DIFFERENT DIELECTRIC BARRIER DISCHARGE CELL

Abstract

Experimental tests of the removal of NOx compounds were carried out in two dielectric barrier discharge cells (DBD) reactors at Physics plasma laboratory of Mexico Nuclear center Two
different geometries of these reactor were studied, one circular 11,94 cm diameter, and another rectangular,16x7 cm, both 2,5 mm gap and 28,0 cm3 reaction volume A gas mixture composed of 1,0 l/m of molecular nitrogen was injected to each reactor along with an additional flow that provided a concentration of 90 ppm of NO in both cells. The gas mixture
was treated with non – thermal plasma generated by dielectric barrier discharge at different working potentials and at a 1,75 kHz frequency. The residual products were identified by means
of a Sensonic 2000 gas analyzer. According to the experimental results, it was identified a greater removal efficiency in the
rectangular cell than in the circular one. This might be attributed both to residence time due to geometric effects and to a factor related with the chemical reaction mechanisms, since it has been showed that, at greater powers, the removal efficiency diminishes due to the regeneration of NO by inverse kinetic mechanisms. Our kinetic model proves that the main reaction product was N2O in the presence of a reducing atmosphere.