Innovative electrostatic spray technology for control of particulate matter emitted from electron beam flue gas treatment process

Abstract

In this study, the efficacy of electrostatic spray technology was assessed for removing particulate matter emitted from flue gas treatment processes utilizing an electron beam. The electron beam treatment of target compounds (NO, NO₂, and SO₂) with additives produced particulate matter. This particulate matter displayed varying number concentration distributions across different particle sizes. The highest number concentration was observed in the 150–250 nm size range. Particulate matter generated from each target compound varied in elemental composition, forming oxidized species that contained oxygen. Increasing the voltage applied to the electrodes of the electrostatic spraying device enhanced the electric field strength, thus charging fine spray droplets of 100 nm diameter emitted from the nozzle. In conditions with low particle number concentration (additive: NaOH, gas: NO and NO₂), even at an applied voltage of 5 kV, high removal efficiencies (ranging from 86.1 % to 96.5 %) were achieved. Under high concentration conditions, which included the treatment of SO₂ with NaOH and all cases with NH₄OH, the removal efficiency peaked at 64 % at 10 kV. When NaOH (0.02 mol/L) was utilized as the electrostatic spray solution, the removal efficiency decreased, yet increasing the applied voltage to 15 kV achieved a removal efficiency of 99.9 %. Enhancements in the applied voltage of the electrostatic spraying device allowed for the treatment of high concentrations of particulate matter generated during the electron beam process and opened up several application possibilities through the modification of the spray solution. These results affirm that electrostatic spraying is a potent technology for treating particulate matter generated in electron beam processes.