Removal of sulfur dioxide and nitrogen oxides by using ozone injection and absorption–reduction technique

A two-step process capable of removing NOx and SO2 simultaneously was proposed, which was made up of an ozonizing chamber and an absorber containing a reducing agent solution. Nitrogen oxides (NO plus NO2) in most practical exhaust gases consist chiefly of NO. The injection of ozone into the exhaust gas gives rise to a rapid oxidation of NO to NO2. Compared to NO, NO2 has relatively high solubility in water, and it can readily be reduced to N2 when the NO2-rich exhaust gas is brought into contact with the reducing agent solution. Sodium sulfide (Na2S) used as the reducing agent in this study can also remove SO2, effectively. As the exhaust gas passed through the ozonizing chamber and the absorber sequentially, NOx removal efficiency of about 95% and SO2 removal efficiency of 100% were obtained. The formation of H2S from sodium sulfide could be suppressed by using a basic reagent, together with the reducing agent. The rate of depletion of the reducing agent during the treatment of the exhaust gas was much faster than expected by reaction stoichiometry, obviously due to the oxygen in the exhaust gas. The amount of sodium sulfide required was found to be about four times the amount of NOx and SO2 removed.

[1]  Kawamura Keita,et al.  Pilot plant experience in electron-beam treatment of iron-ore sintering flue gas and its application to coal boiler flue gas cleanup , 1984 .

[2]  John B. Shoven,et al.  I , Edinburgh Medical and Surgical Journal.

[3]  W. T. Davis,et al.  Air Pollution: Its Origin and Control , 1976 .

[4]  U. Kogelschatz.  Dielectric-Barrier Discharges: Their History, Discharge Physics, and Industrial Applications , 2003 .

[5]  L. C. Thomas,et al.  Colorimetric chemical analytical methods , 1974 .

[6]  Mehl Wolfgang,et al.  Air pollution control , 1971 .

[7]  Long Grove, Illinois , 2006 .

[8]  B. Rajanikanth,et al.  Studies on nitric oxide removal in simulated gas compositions under plasma-dielectric/catalytic discharges , 2001 .

[9]  Andrew G. Glen,et al.  APPL , 2001 .

[10]  Y. Mok,et al.  Reduction of nitrogen oxides from simulated exhaust gas by using plasma–catalytic process , 2004 .

[11]  C. J. Matale.  Air Pollution Control , 2000 .

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

[13]  M. Okubo,et al.  Simultaneous removal of NO/sub x/, SO/sub x/, and CO/sub 2/ at elevated temperature using a plasma-chemical hybrid process , 2002 .

[14]  Kazuhiko Tsuji,et al.  Combined desulfurization, denitrification and reduction of air toxics using activated coke: 1. Activity of activated coke , 1997 .

[15]  Y. Mok.  Oxidation of NO to NO2 Using the Ozonization Method for the Improvement of Selective Catalytic Reduction , 2004 .

[16]  S. Bröer,et al.  Selective catalytic reduction of nitrogen oxides by combining a non-thermal plasma and a V2O5-WO3/TiO2 catalyst , 2000 .

[17]  Bernard Delmon,et al.  Catalytic removal of NO , 1998 .

[18]  M. Elsener,et al.  Reaction Pathways in the Selective Catalytic Reduction Process with NO and NO2 at Low Temperatures , 2001 .