Investigation of flue-gas treatment with O3 injection using NO and NO2 planar laser-induced fluorescence

Direct ozone (O3) injection is a promising flue-gas treatment technology based on oxidation of NO and Hg into soluble species like NO2, NO3, N2O5, oxidized mercury, etc. These product gases are then effectively removed from the flue gases with the wet flue gas desulfurization system for SO2. The kinetics and mixing behaviors of the oxidation process are important phenomena in development of practical applications. In this work, planar laser-induced fluorescence (PLIF) of NO and NO2 was utilized to investigate the reaction structures between a turbulent O3 jet (dry air with 2000 ppm O3) and a laminar co-flow of simulated flue gas (containing 200 ppm NO), prepared in co-axial tubes. The shape of the reaction zone and the NO conversion rate along with the downstream length were determined from the NO-PLIF measurements. About 62% of NO was oxidized at 15d (d, jet orifice diameter) by a 30 m/s O3 jet with an influence width of about 6d in radius. The NO2 PLIF results support the conclusions deduced from the NO-PLIF measurements.