Simultaneous treatment of NO and SO2 with aqueous NaClO2 solution in a wet scrubber combined with a plasma electrostatic precipitator

Abstract

NO and SO2 gases that are generally produced in thermal power plants and incinerators were simultaneously removed by using a wet scrubber combined with a plasma electrostatic precipitator. The wet scrubber was used for the absorption and oxidation of NO and SO2, and non-thermal plasma was employed for the electrostatic precipitation of aerosol particles. NO and SO2 gases were absorbed and oxidized by aerosol particles of NaClO2 solution in the wet scrubber. NO and SO2 reacted with the generated NaClO2 aerosol particles, NO2 gas, and aqueous ions such as NO2−, NO3−, HSO3−, and SO42−. The aerosol particles were negatively charged and collected on the surface of grounded anode in the plasma electrostatic precipitator. The NO and SO2 removal efficiencies of the proposed system were 94.4% and 100% for gas concentrations of 500mg/m3 and a total gas flow rate of 60Nm3/h, when the molar flow rate of NaClO2 and the gas–liquid contact time were 50mmol/min and 1.25s, respectively. The total amount and number of aerosol particles in the exhaust gas were reduced to 7.553μg/m3 and 210/cm3 at the maximum plasma input power of 68.8W, which are similar to the values for clean air.