Experimental study of electrostatic precipitator performance and comparison with existing theoretical prediction models

A laboratory-scale single-stage electrostatic precipitator (ESP) was designed, built and operated in a wind tunnel. As a "rst step, a series of experiments were conducted to seek the operating conditions for increasing the particle collection e$ciency by varying basic operating parameters including the wire-to-plate spacing, the wire radius, the air velocity, the turbulence intensity and the applied voltage. As the diameter of the discharging wires and the wire-toplate spacing are set smaller, the higher collection e$ciency has been obtained. In the single-stage multiwire ESP, there exists an optimum wire-to-wire spacing which provides maximum particle collection e$ciency. As the air velocity increases, the particle collection e$ciency decreases. The turbulent #ow is found to play an important role in the relatively low electric "eld region. In the high electric "eld region, however, particles can be deposited on the collection plates readily regardless of the turbulence intensity. The experimental results were compared with existing theories and Zhibin and Guoquan (Aerosol Sci. Technol. 20 (1994) 169}176) was identi"ed to be the best model for predicting the ESP performance. As the second step, the in#uence of particle contamination at the discharging electrode and at the collection plates were experimentally measured. The methods were sought for keeping the high collection e$ciency of ESP over elapsed time by varying the magnitude of rapping acceleration, the time interval between raps, the types of rapping system (hammer/vibrator) and the particle reentrainment. The rapping e$ciency and the particle re-entrainment were increased with increasing magnitude of rapping acceleration and time interval between raps. However, when the thickness of deposited #y ash layer is su$ciently high, the concentration of re-entrained particles starts decreasing abruptly due to the agglomeration force which can interact among 0304-3886/99/$ see front matter ( 1999 Elsevier Science B.V. All rights reserved. PII: S 0 3 0 4 3 8 8 6 ( 9 9 ) 0 0 0 4 4 3 deposited particles. The combined rapping system is found more e!ective for removing deposited particles than the hammer rapping system only. ( 1999 Elsevier Science B.V. All rights reserved.