ICLASS 97
Proceedings of the Seventh International Conference on Liquid Atomization and Spray Systems

ISBN Print: 89-950039-2-8

Application of Electrostatic Spraying to Reduce SO2 Emission in a Laboratory - Scale Spray Drying Absorber

DOI: 10.1615/ICLASS-97.1410
pages 1146-1153

Abstract

Emission control of acid exhaust gas.es from coal-fired power plants and waste incinerators has become an increasing concern of both industries and regulators. Among those gaseous emissions, SO2 has been eliminated by a Spray Drying Absorber (SDA) system, where the exhaust gas is mixed with atomized slaked lime slurry droplets and then the chemical reaction of SO2 with alkaline components of the liquid feed forms sulfates. Liquid atomization is necessary because it maximizes the reaction efficiency by increasing the total surface area of the alkaline components. An experimental study was performed with a laboratory-scale SDA to investigate whether the efficiency for SO2 reduction increased or not with application of a DC electric field to the slurry. For selected experimental conditions concentrations of SO2 exited from the reactor were measured with various applied voltages and slurry flow rates. The applied voltage varied from -10 to l0kV, and the volume flow rate of slurry was set to 15, 25, 35 ml/min. Consequently, the SO2 scrubbing efficiency increased with increasing the applied voltage but was independent of the polarity of the applied voltage. For the electrical and flow conditions considered a theoretical study of estimating average size and charge of the atomized droplets was carried out based on the measured current-voltage characteristics. For a given slurry flow rate the droplet charge to mass ratio increased and the droplet diameter decreased as the strength of the applied voltage increased