Simultaneous treatment of NO and SO_2 with aqueous NaClO_2 solution in a wet scrubber combined with a plasma electrostatic precipitator

摘要

NO and SO_2 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 SO_2, and non-thermal plasma was employed for the electrostatic precipitation of aerosol particles. NO and SO_2 gases were absorbed and oxidized by aerosol particles of NaClO_2 solution in the wet scrubber. NO and SO_2 reacted with the generated NaClO_2 aerosol particles, NO_2 gas, and aqueous ions such as NO_2~-, NO_3~-, HSO_3~-, and SO_4~(2-).The aerosol particles were negatively charged and collected on the surface of grounded anode in the plasma electrostatic precipitator. The NO and SO_2 removal efficiencies of the proposed system were 94.4% and 100% for gas concentrations of 500 mg/m~3 and a total gas flow rate of 60 Nm~3/h, when the molar flow rate of NaClO_2 and the gas-liquid contact time were 50 mmol/min and 1.25 s, respectively. The total amount and number of aerosol particles in the exhaust gas were reduced to 7.553 μg/m~3 and 210 /cm~3 at the maximum plasma input power of 68.8 W, which are similar to the values for clean air.