Investigation on Removal of NOx and SO2 From Flue Gas by Combined Ozone With Absorption and By-Product Treatment

Abstract

The combination of ozone with washing tower and an absorption products recovery system was utilized for removal of NOx and SO2 from flue gas. In our previous studies, more than 90% NO can be oxidized by ozone. In this study, three kinds of absorbents, Na2SO3, CaSO3 and Ca(OH)2, were evaluated for simultaneous absorption of NO2 and SO2 in the wet scrubbing. It was found that NO2 absorption efficiency was increasing with S(IV). Effect of different concentration of CaSO3 on NO2 absorption was investigated. Results show that nearly 70% NO2 can be absorbed in calcium sulfite slurry. Furthermore, NO2 absorption efficiency is increasing to 85% in the sulfite with assistant of MnSO4. In the meantime, the absorption efficiency of SO2 is always nearly 100%. A new system is built for recycling NO2 absorption products and purifying the waste water, which has the advantages of low investment and operating cost.