Electron Beam Ionization for Coal Fly Ash Precipitators

Coal fly ash removal by electrostatic precipitation strongly depends on ion current flux and electric field geometry. In preliminary experiments with accelerated electron beams passing through air, ion current densities have been measured which are 50 times larger than those which can be obtained in a duct type electrostatic precipitator with corona ionization. Theoretical calculations show that even larger values can be obtained with driving voltages higher than the 10 kV available in the preliminary experiments. An additional advantage of the high ion current flux is the enhancement of the electric fields in the vicinity of the collection plate. These results are the basis for a design of an experimental precipitator system with which to test electron beam ionization on reentrained coal fly ash. A further possible application of electron beams lies in the fact that energetic electrons will ionize solid materials as well as gases. Consequently, electron irradiation will reduce resistivity in the fly ash layer deposited on a conduction plate.