Oxidation of NO with O3 under different conditions and the effects of SO2 and H2O vapor

Abstract

In order to achieve better chemical absorption of NOx and SOX, oxidation of NO in the process of simultaneous desulfurization and denitrification of the flue gas based on ozone oxidation was studied. The main investigations focused on factors affecting NO oxidation including the molar ratio of O3/NO (MR) (0.6–1.2), the oxidation temperature (65−150°C), the initial NO concentration (100−500mg/Nm3), the presence of SO2 (1000−5000mg/Nm3), the content of water vapor (5–15 %) and the residence time (0.07–1.8s). The results indicated that MR had a substantial effect on NO conversion and the products of NO oxidation by O3 varied with the change of MR. When MR≤1, the NO conversion increased from less than 60 % to more than 95 % with the increase of MR, and the oxidation product was mainly NO2. When MR(O3/NO) > 1, the NO conversion rate (about 97 %) basically remained unchanged, and the oxidation products under these circumstances were mainly NO2 and N2O5. When the oxidation temperature rose from 65 to 150℃, the conversion of NO was almost unchanged. Besides, the NO initial concentration, the presence of SO2, the water vapor content and the length of the flue gas outlet pipe had negligible impact on the NO conversion within the range selected for the study.