Experimental study of the mass balance in a pilot industrial electrostatic precipitator

Simultaneous measurements of the mass collection rates by plates and hoppers have been realized along a pilot ESP in an industrial environment, together with on-line current, voltage, opacity measurements; they have been associated with on-site measurements of particle concentration and resistivity, and with records of the operating conditions of the both boiler and the electrostatic precipitator. Using these measurements, it has been possible to reconstruct the detailed mass balance across the precipitator, under different operating conditions, depending on corona current and rapping sequences. It has been quantified that the best performances are obtained under slow rapping conditions and for current levels around the back-corona threshold. The detailed mass balance combined with size distribution of the fly ash may be very useful for the validation of theoretical models, in much more detail than through previously available published data. Continuous mass transfer from the collecting plates into the hoppers, independent on rapping shots, has been also put in evidence.