ASSESSMENT OF ATOMIZATION QUALITY WITH RESPECT TO BURNOUT FOR THE INCINERATION OF ORGANICALLY CONTAMINATED WASTE-WATERS

Three different air-assist nozzles were investigated with a Phase-Dopp ler-Analyzer and high speed photography in a cold environment and then used in a pilot scale furnace at a thermal input of 200 kW. Waste wat er was simulated by a water - glycol mixture. Measurements showed temp eratures above 1100 degrees C and homogeneous oxygen concentrations ex cept close to the burner. With such conditions evaporation and, hence, atomization quality set the limits on burnout, as oxidizing reactions are fast. The Sauter Mean Diameter (SMD) did not correlate closely wi th burnout since SMD indicates a mean droplet size while performance i s limited by the number of large droplets present. Better agreement wa s achieved for D-90% which is a parameter that represents the upper en d of the size distribution. High speed photography is recommended to d etect and measure the largest droplets in the spray. Their size correl ated closely with the onset of incomplete burnout and is, therefore, a n appropriate parameter to characterize atomization quality with respe ct to burnout.