Experimental study of a tubular-type ESP for small-scale biomass boilers. Preliminary results in a diesel engine

Particle emission (PM) is a large source of air pollution, so that research on this topic for minimizing the well-known health problems is currently developed. Various devices can be employed to remove these particles; however, electrostatic precipitators (ESPs) exhibit advantages when submicron particles must be treated. In this study, a lab-scale tubular type ESP is designed, constructed and tested with the main purpose of broadening the lack of experimental results with this kind of ESP. A series of experiments are performed using a small-size diesel internal combustion engine as the smoke and PM source. A smoke meter and a low-pressure impactor are used as measuring devices. A correlation between opacity and particle concentration is obtained and compared with the literature. The theoretical voltage-intensity (VI) curve of the ESP is compared with experimental values. In addition, the influence of some well-known operative parameters on the VI curves is evaluated (voltage polarity, discharge electrode diameter and humidity) to ascertain their influence. On the other hand, the effect of the discharge electrode temperature and fouling is included in this work. Short test durations and high collection efficiencies are obtained with negative voltages. Finally, an interesting design tip can be extracted; structures linking discharge and collection electrodes should be avoided in the flue gas to prevent unexpected electrical currents due to fouling.