Mechanisms and reaction pathways for simultaneous oxidation of NOx and SO₂ by ozone determined by in situ IR measurements.

Ozone (O3) oxidation combined with wet scrubbing is a promising method for the simultaneous removal of SO2 and NOx in flue gas. In this study, the O3 oxidation processes of NO and SO2, as well as their coexistence, were investigated using an in situ IR spectrometer. Experimental results showed that the O3 concentration and the reaction temperature played critical roles in the O3 oxidation process of NO. Around 80°C, when inlet molar ratio of O3/NO was less than 1, NO was mainly oxidized to NO2, while when the ratio was greater than 1, NO would be further oxidized to NO3, N2O5, and HNO3. NO3 was the key intermediate product for the formation of N2O5 and HNO3. However, the subsequent reactions of NO3 were temperature dependence. With the increase of reaction temperature above 100°C, the concentration of NO2 increased whereas the concentrations of N2O5 and HNO3 decreased. The oxidation of SO2 by O3 was negligible and SO2 had little influence on the oxidation of NO in the simultaneous oxidation of NO and SO2. Finally, based on the in situ IR results, the oxidation mechanism is discussed and the reaction pathways are proposed.

[1]  S. Bhatia,et al.  Cerium impregnated palm shell activated carbon (Ce/PSAC) sorbent for simultaneous removal of SO2 and NO—Process study , 2010 .

[2]  R. Batiuk,et al.  Nitrogen oxides: Impacts on public health and the environment , 1997 .

[3]  Zhihua Wang,et al.  Effect of Additive Agents on the Simultaneous Absorption of NO2 and SO2 in the Calcium Sulfite Slurry , 2012 .

[4]  V. Grassian,et al.  N2O5 hydrolysis on the components of mineral dust and sea salt aerosol: Comparison study in an environmental aerosol reaction chamber , 2006 .

[5]  C. Sheng,et al.  Kinetic model of NO removal from SO2-containing simulated flue gas by wet UV/H2O2 advanced oxidation process , 2011 .

[6]  T. Overcamp,et al.  Hydrogen Peroxide Scrubber for the Control of Nitrogen Oxides , 2002 .

[7]  Kinga Skalska,et al.  Trends in NO(x) abatement: a review. , 2010, The Science of the total environment.

[8]  G. Halsey,et al.  Infrared Spectrum and Thermodynamic Properties of Gaseous Sulfur Trioxide , 1962 .

[9]  Linjun Yang,et al.  Separation of Fine Particles from Gases in Wet Flue Gas Desulfurization System Using a Cascade of Double Towers , 2012 .

[10]  Young Sun Mok,et al.  Removal of sulfur dioxide and nitrogen oxides by using ozone injection and absorption–reduction technique , 2006 .

[11]  Yue Liu,et al.  Mechanism Study of NO Catalytic Oxidation over MnOx/TiO2 Catalysts , 2011 .

[12]  S. Ledakowicz,et al.  Kinetic model of NOx ozonation and its experimental verification , 2011 .

[13]  Hai-Long Li,et al.  Simultaneous removal of SO2, NO and mercury using TiO2-aluminum silicate fiber by photocatalysis , 2012 .

[14]  S. Ledakowicz,et al.  Effectiveness of nitric oxide ozonation , 2011 .

[15]  J. Jia,et al.  Bromine chloride as an oxidant to improve elemental mercury removal from coal-fired flue gas. , 2009, Environmental science & technology.

[16]  H. Shaw,et al.  Aqueous absorption of nitric oxide induced by sodium chlorite oxidation in the presence of sulfur dioxide , 1998 .

[17]  Hyung-Keun Lee,et al.  Simultaneous removal of SO2 and NO by wet scrubbing using aqueous chlorine dioxide solution. , 2006, Journal of hazardous materials.

[18]  Yue Liu,et al.  Novel H2Ti12O25-Confined CeO2 Catalyst with Remarkable Resistance to Alkali Poisoning Based on the “Shell Protection Effect” , 2011 .

[19]  Wenju Jiang,et al.  Simultaneous absorption of NOx and SO2 from flue gas with pyrolusite slurry combined with gas-phase oxidation of NO using ozone. , 2011, Journal of hazardous materials.

[20]  Yangxian Liu,et al.  Simultaneous Removal of NO and SO2 from Flue Gas by UV/H2O2/CaO , 2012 .

[21]  U. Platt,et al.  Absolute Determination of the Temperature Behavior of the NO2+ NO3+(M) ↔ N2O5+ (M) Equilibrium , 1997 .

[22]  J. Jia,et al.  Significance of RuO2 modified SCR catalyst for elemental mercury oxidation in coal-fired flue gas. , 2011, Environmental science & technology.

[23]  Zhenyu Liu,et al.  Regeneration of Al2O3-Coated Cordierite Supported CuO for Simultaneous SO2 and NO Removal , 2005 .

[24]  Kefa Cen,et al.  Direct Numerical Simulation of Ozone Injection Technology for NOx Control in Flue Gas , 2006 .

[25]  Zbigniew Zimek,et al.  Electron beam flue gas treatment (EBFGT) technology for simultaneous removal of SO2 and NOx from combustion of liquid fuels , 2008 .

[26]  Y. Mok,et al.  Effect of Ozone Injection on the Catalytic Reduction of Nitrogen Oxides , 2006 .

[27]  Y. Mok,et al.  Reduction of nitrogen oxides by ozonization-catalysis hybrid process , 2004 .

[28]  Y. Mok.  Absorption–reduction technique assisted by ozone injection and sodium sulfide for NOx removal from exhaust gas , 2006 .

[29]  Stanisław Ledakowicz,et al.  Intensification of NOx absorption process by means of ozone injection into exhaust gas stream , 2012 .

[30]  E. Stamate,et al.  IR and UV gas absorption measurements during NOx reduction on an industrial natural gas fired power plant , 2010 .

[31]  Yi Zhao,et al.  Simultaneous removal of SO2 and NO using M/NaClO2 complex absorbent , 2010 .

[32]  M. Wilk,et al.  Nitrogen Oxides Ozonation as a Method for NOx Emission Abatement , 2012 .

[33]  G. Zeng,et al.  Hg0 Removal from Simulated Flue Gas over CeO2/HZSM-5 , 2012 .

[34]  Jong-Seok Oh,et al.  Application of pulsed corona induced plasma chemical process to an industrial incinerator. , 2003, Environmental science & technology.

[35]  Kefa Cen,et al.  Simultaneous removal of NOx, SO2 and Hg in nitrogen flow in a narrow reactor by ozone injection: Experimental results , 2007 .

[36]  Yi Zhao,et al.  Simultaneous desulfurization and denitrification from flue gas by Ferrate(VI). , 2011, Environmental science & technology.

[37]  Zijun Tang,et al.  Simultaneous removal of SO2, NO and Hg-0 by wet scrubbing using urea + KMnO4 solution , 2013 .