Size Distribution of Heavy Metal Aerosols in Cooling and Spray Dryer System

Abstract

The cooling process prior to treating flue gas and the spray dryer process that removes acid components in flue gas are believed to influence the mass and elemental size distributions of heavy metal in fly ash. The main objective of this study was to investigate the effects of operating parameters on the mass and elemental size distributions of heavy metals in fly ash produced from a fluidized bed incineration and a water cooling or spray dryer flue gas treatment system. The operating parameters investigated included (1) the controlling temperature in the gas cooling system; (2) the controlling temperature in the spray dryer system; (3) the addition of organic chloride; and (4) the addition of inorganic chloride. The experimental results indicated that the water cooling process and spray dryer process increase the amount of coarse fly ash (5–125 μm) and increase the total concentration of metal in fly ash. The amounts of fine fly ash (0.1–15.72 μm) and the total concentration of metal in fine fly ash increase with decreasing temperature during the water cooling process. However, the amounts of fine fly ash (0.1–15.72 μm) and the total concentration of metal in fine fly ash decrease with decreasing temperature during the spray dryer process.