Reaction mechanism of NO_x removal from flue gas with pyrolusite slurry

摘要

Pyrolusite slurry was used as absorbent to remove NO_x from flue gas. Reaction mechanism of NO_x removal was theoretically analyzed based on E-pH diagram of Mn-NO_x-H2O system and then verified by experiments via both the qualitative and quantitative analysis of reaction products. Main reaction and byproduct were also investigated in depth. Results showed that NOX in flue gas dissolved into liquid phase first and then were oxidized into NOJ by MnO2 and O2. NO2 was more easily removed than NO because of its high solubility. NO_x removal efficiency was depended strongly on the molar ratio of NO2 to NO_x (NO2/NO_x ratio). When NO2/NO_x ratio at 75%, NO_x removal efficiency remained between 60% and 64% within 11 h and manganese extraction rate reached 92%. Manganese nitrate, meeting the needs of national industry grade standards, could be produced using purified absorption solution.