Photochemical removal of NO and SO2 from flue gas using UV irradiation

Abstract

ABSTRACTThe simultaneous oxidation and removal efficiencies of SO2 and NO from simulated coal‐fired flue gas by UV irradiation were investigated experimentally. The influencing factors, such as the reaction temperature, the content of O2, H2O, SO2, and NO, on the removal of SO2 and NO were studied. The results indicated that NO had positive effect on the removal of SO2. Compared with the NO‐free case, the removal efficiency of SO2 was improved from 8% to 55% in the presence of 250 ppm NO. When the NO concentration rose from 250 to 700 ppm, the SO2 removal efficiency further increased from 55% to 64%. The increasing of reaction temperature enhanced the removal efficiencies of SO2 and NO, which increased by 28% and 36%, respectively, with the reaction temperature rising from 270 to 350 °C. It was found that O2 was conducive to the photochemical oxidization due to the generation of free radicals. As the O2 content increased from 0% to 8%, the removal efficiencies of NO and SO2 reached 40% and 55%, respectively. The positive effect of H2O on the simultaneous removal of NO and SO2 was also observed. The optimal conditions (250 ppm NO, 100 ppm SO2, 8% O2, 5% H2O, and reaction temperature 350 °C) were determined, and the removal efficiencies of SO2 and NO were 55% and 40%, respectively. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.