Improving NO Reduction Efficiency by Acoustic Oscillations
S.Nemeth, S.V.Komarov, M.Hirasawa (Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan)
In high temperature processes, one of the most harmful air pollutants is the nitrogen oxide NO. The present study has been focused on a possibility for improving NO reduction efficiency by application of powerful sound waves (frequency 6.9~17.2 kHz, intensity 144~160 dB) that were produced by Hartmann sound generators mounted on the top of a vertical reaction tube (height 1.8 m, I.D. 105 mm). A graphite disc was positioned in the tube bottom part preheated up to certain temperatures (873~1173 K). An Ar-NO synthetic gas mixture (NO 911~934 ppm) was injected onto the disc surface to perform reactions 2C+2NO=N2+2CO and C+2NO=N2+CO2. Without sound wave application NO content in the flue gas was reduced to a level of 200-600 ppm. Exposing the disc surface to sound waves resulted in the further decrease in NO concentration 50~250 ppm values. The effect of NO reduction efficiency was found to be dependent on the sound frequency, intensity, gas flow rate and temperature.
Section : 11