Dry De-NOx via Gas-Phase Photochemical Oxidation Using an Ultraviolet and Aerosolized H2O/H2O2 Hybrid System

Abstract

A dry de-NOx technique based on a highly efficient photochemical oxidation process was demonstrated for a simulated flue gas of a diesel engine using a lab-scale reaction chamber. A hybrid system of an ultraviolet (UV185, (254 nm)) lamp and aerosolized H2O/hydrogen peroxide (H2O2) was employed. De-NOx characteristics when using an UV lamp, an aerosolized H2O/H2O2 solution, and a hybrid system of both components were investigated individually. The UV lamp treatment had a significant impact on the de-NOx process by generating ozone, while the aerosolized H2O/H2O2 solution showed less effect because of the ambient temperature when the system was operated separately. With the assistance of UV light, however, aerosolized H2O/H2O2 contributed to the oxidation reaction and NO and NO2 removal efficiencies of up to 100 and 97.8%, respectively, were achieved. Ammonia was introduced into the reaction chamber to solidify and remove the oxidized nitric oxide (NO) through the formation of ammonium nitrate aerosols. Scanning electron microscopy and energy-dispersive spectroscopy analysis were used to identify and interpret the particulate byproducts after the reaction.