Electrostatic enhancement of the collection efficiency of stainless steel fiber filters

This study investigated the effect of using a stainless steel fibrous filte r as the ground electrode of a point-to-plate electrostatic precipitator on particle penetration. The effect of the electrical field on particle penet ration was investigated at 4 different filter face velocities (25, 50, 100, and 125 cm/s) for monodisperse PSL and silica particles (size range 0.05-1 m) as well as polydisperse ammonium sulfate, ammonium nitrate, and ultrafi ne indoor air particles. Particle penetration was greatly reduced by the ap plication of the electrical field. By comparison, the performance of electr ically active fibrous filters has been shown to rapidly degrade as particle loading exceeds 2-3 g/m(2). The effect of particle loading on particle pen etration was also investigated at a filter face velocity of 50 cm/s. Partic le penetration seemed to slightly decrease with particle loading and was in dependent of particle size. These results indicated that the accumulation o f nonconductive particles up to 15 cm(3)/m(2) does not create "back corona, " which would substantially decrease the collection efficiency of the groun ded filter. In conclusion, our experiments suggest that using metal filters as the collector electrodes mag be an attractive alternative design for el ectrostatic precipitators.