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 s mall laboratory test unit (max. gas flow rats = 1 Nm(3)/h) for exhaust gas cleaning by means of electron beam and combined electron beam-mic rowave irradiation. The aim of these methods is to obtain the concomit ant removal of the NOx and SO2 by precipitation with ammonia. Several parameters such as residence time and dose, reaction temperature, argo n and NH3 concentration, etc. were investigated. The removal efficienc ies 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 arg on in the irradiated gaseous mixture increases the SO2 removal efficie ncy (between 5% and 10%) for both electron beam and electron beam-micr owave treatment. As electron beams generator was used the Linear Accel erator 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 directiona l coupler and a three stub tuner for impedance matching. Our tests als o demonstrated that the combined method electron beam-microwave irradi ation, due to the additional use of microwave energy, leads to the dec rease of the electron beam average power from 30% to 50%, at the same removal efficiency. (C) 1998 Elsevier Science B.V.