NOMENCLATURE

Gaseous SO3 (H2SO4) condenses into a nucleus and becomes sulfuric acid mist in a cooling process such as the wet flue gas desulfurization system (WFGD). The relation between the temperature condition of this cooling process and particle size of mist was examined by condensation theory and experiment s. In addition, the collecting efficiency and electric current density of a wet electrostatic precipitator (WESP) were examined with the mist generated by the cooling process. Particle sizes of mist were measured at 30 ppm of SO3 under various cooling conditions, and were measured in the case where fine particles of ammonium sulfate were supplied by spray-drying. The particle size of the nucleus into which mist condenses depended on the speed at which the gas is cooled. At a slower cooling speed, mist did not condense into small particles. This indicates that the particle size of mist grows in the range where the gas temperature around the SO3 condensation temperature is lowered slowly. The electric current density of THE model ESP increased when the particle size of mist was larger, and the collecting efficiency was improved, too. This indicates that the specific collecting area of the ESP is influenced by the cooling condition