Hydrazine-enhanced NO conversion in a pulsed corona discharge plasma (PCDP) reactor: Behaviors and mechanism

摘要

The NO conversion efficiency in a pulsed corona discharge plasma (PCDP) reactor in the presence of a new additive, hydrazine hydrate (N₂H₄·H₂O), was studied, and the reaction mechanism was analyzed. The NO conversion efficiency reached 62.5%, and the NO conversion Energy Yield (E_Y) reached 20.9 g_NO/kWh, which is higher than that obtained using water or ammonia additives under the same conditions. The predominant elementary reactions and radicals, as well as the mechanism by which the additive enhanced the NO conversion process, were determined by comparing experimental data with theoretical simulation results and by performing a sensitivity analysis. After the addition of N₂H₄·H₂O, the N₂H₄ reacts with radicals generated in the PCDP reactor to form a large quantity of strongly reducing species with NH₂ as the predominant component, which can directly reduce NO to N₂ and effectively prevent the generation of N₂O. Compared with the traditional PCDP-based De-NO_x process in which nitric acid is generated by oxidation with an additional neutralization step required, this new PCDP-based De-NO_x process with N₂H₄·H₂O addition is superior because NO is mostly reduced to N₂. The study provides a basis for the application of N₂H₄·H₂O as a synergist to improve NO abatement in a PCDP reactor.