Pulse‐energized wet tubular electrostatic precipitator for NOx emission control
Chenlu Yang · Environmental Progress · 1999
Abstract A tubular plasma reactor was used to evaluate the feasibility of oxidizing nitric oxide (NO) by corona discharge. The DC corona completely oxidized 115 ppm of NO to nitrogen dioxide (NO2) in an air stream at a voltage of 11 kV. The NO2 was further oxidized to nitrate at a voltage of 13 kV. In some cases, the residual NO2 in the effluents of the plasma reactor was removed quantitatively by absorption in aqueous causticsodium sulfite. The outlet concentrations of both NO and NO2 from the combined corona discharge and aqueous absorption system were beyond the detection limit of a chemiluminescent NOx analyzer. Both NO oxidation and NO2 absorption were confirmed in a pilot‐scale wet tubular electrostatic precipitator (WESP) that has a 4‐foot high corona discharge section and a 5‐foot high gas absorption section. The flue gas from the sewage sludge incinerator, containing 8 ppm NO and 78 ppm NO2, was tested in the system. The WESP was energized with a pulsed power supply to avoid premature spark‐over. In the plasma discharge section, 79% of the NO2 was reduced while virtually 100% of the NO was oxidized at a pulse voltage of 55 kV. The outlet concentration of NO2 from the absorption section was 2 ppm.