Dual oxidant and reactant interactions in NEPE pyrolysis: Experimental and kinetic modelling insights

Abstract

The reaction of dual oxidants (NO2 and O2) and dual reactants (NH3 and CH2O) obtained from the pyrolysis of NEPE was investigated both experimentally and numerically. Experiments were performed in JSR at atmospheric pressure, at low and medium temperatures of 600–1000 K, with equivalence ratios of 0.67–1.33, and the species concentrations of reactants, intermediates, and products were measured. A detailed kinetic model was then developed, which can capture the experimental results. The kinetic analysis revealed that NO2 was the main oxidant at low temperatures, as the temperature increased, O2 became more competitive, reducing the flux of the NO2 consumption pathway. Additionally, NO shows a non-monotonic trend with increasing temperature. On the one hand, this is due to the competition between O2 and NO2, which leads to a decrease in the flux of NOx formation. On the one hand, at higher temperature, HCO tended to decompose to produce H, which converted NO2 to NO by the reaction NO2 + H = NO + OH, increasing the fluxes of NH2 and NO and leading to an increase in DeNOx pathway flux. Furthermore, the O2 concentration directly affected the activity of the reaction system. This is because O2 accelerates the reaction NO + HO2 = NO2 + OH through HO2 generated by the reaction HCO + O2 = CO + HO2, and this pathway not only replenishes NO2 but also provides a large amount of OH.