A laboratory test unit for exhausted gas cleaning by electron beam and combined electron beam-microwave irradiation

At the Electron Accelerator Laboratory, NILPR. Bucharest developed a small laboratory test unit (max. gas flow rats = 1 Nm(3)/h) for exhaust gas cleaning by means of electron beam and combined electron beam-microwave irradiation. The aim of these methods is to obtain the concomitant removal of the NOx and SO2 by precipitation with ammonia. Several parameters such as residence time and dose, reaction temperature, argon and NH3 concentration, etc. were investigated. The removal efficiencies were: only for electron beam irradiation 63-80% for SO2 and 0-63% for NOx; for combined electron beam-microwave treatment 68-95% for SO2 and 0-70% for NOx. Also, the presence of a small concentration of argon in the irradiated gaseous mixture increases the SO2 removal efficiency (between 5% and 10%) for both electron beam and electron beam-microwave treatment. As electron beams generator was used the Linear Accelerator ALID-7 (5.5 MeV, 670 W). The microwave applicator consists of a power-controlled generator with a 2.45 GHz magnetron of 850 W maximum output power, a launcher to fit to waveguide WR430, a dual directional coupler and a three stub tuner for impedance matching. Our tests also demonstrated that the combined method electron beam-microwave irradiation, due to the additional use of microwave energy, leads to the decrease of the electron beam average power from 30% to 50%, at the same removal efficiency. (C) 1998 Elsevier Science B.V.