A novel integrated method of vapor oxidation with dual absorption for simultaneous removal of SO2 and NO: Feasibility and prospect

This paper proposes a novel method for simultaneously deep removal of SO2 and NO, namely H2O2/Na2S2O8 vapor oxidation with dual absorption by Na2CO3-Na2SO3, which includes three parts (1) pre-absorption of SO2 by Na2CO3; (2) vapor oxidation of NO by vaporized H2O2/Na2S2O8; (3) post-absorption of SOx/NOx by Na2SO3. Of note, Na2SO3 used in the post-absorber was discharged from the pre-absorber. This integrated system could realize the ultra-low emission standards of SO2 and NOx. The best ratio of H2O2/Na2S2O8 was determined as 12.5: 0.3% wt/wt. O-2 and CO2 were found to be the promoter and inhibitor for NO removal respectively. Based on the characterization results by EDS, XRD and XPS, the components in the removal products were identified as Na2SO4 and NaNO3. Finally, the application prospect of this integrated system was briefly discussed.