Advanced Flue-Gas cleaning by wet oxidative scrubbing (WOS) using NaClO2 aqueous solutions

In this work, we investigate the use of a Wet-Oxidative Scrubber (WOS) to simultaneously control SO2 and NOx emissions from exhaust flue-gases. The experiments are performed in a pilot-scale scrubber with a simulated flue-gas containing 500 ppmv of SO2 and 1030 ppmv of NOx, using water doped with 0.25–1% w/w of NaClO2. The results prove that the adopted WOS is able to simultaneously remove SO2 and NOx, and a synergistic effect is observed for the presence of SO2 in the flue-gas, which improves the NOx removal by establishing more effective and faster oxidative mechanisms under acidic conditions. A predictive model of the WOS unit performance based on the experimental dosage of NaClO2, which takes into account for all the operating parameters of the process, is developed to predict the de-SOx and de-NOx efficiencies and also the wash water pH.