Oxidation of Ammonium Sulfite Using Multi-Needle-to-Plate Negative DC Corona Discharge Reactor
Y. Wu, H. Ren, S. Tang, J. Li, N. Lu, and K. Shang
Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), Institute of Electrostatics and Special Power, Dalian University of Technology, PR China
Abstract- For ammonia flue gas desulfurization (FGD) process, the low oxidation rate of ammonium sulfite is a problem that is required to be solved. An experimental study on the oxidation of ammonium sulfite to ammonium sulfate was carried out in the multi-needle-to-plate negative DC corona discharge reactor. Corresponding oxidation rates of ammonium sulfite under the different experimental conditions were investigated and the oxidizing mechanism was also discussed. The results reveal that the oxidation rate of ammonium sulfite increases with the absolute value of discharge voltage and increases first and then decreases as both the flow rate of the ammonium sulfite solution and the initial pH value increase. The oxidation rate of ammonium sulfite can reach the highest under the optimal conditions that the flow rate is 300 mL/min and pH is 7.00. The hydroxyl radicals play a key role in the process of plasma induced ammonium sulfite oxidation. These results would be important for the process optimization of the (NH4)2SO3 to (NH4)2SO4 oxidation.
Keywords- Ammonium sulfite oxidation, corona discharge, multi-needle-to-plate electrode, discharge plasma, ammonia flue gas desulfurization