Collector Current Density and Dust Collection in Electrostatic Precipitators

Deutsch collection theory was developed for tubular geometry and applied to wire-plate ESP without taking into account the differences in geometry and current density distribution. Investigations revealed a square law relationship between the collector electric field and collector current density in space charge dominated coronas. Applying this relationship to Deutsch collection theory led to a new collection formula which is used to assess the impact on ESP performance due to the uneven current density distribution. A new concept of distributed corona impedance is developed to assess the effect of the dust layer on collection performance. It shows that optimal wire-plate ESP collection is obtained with the wire-wire spacing less than the wire-plate distance, confirming published experimental results. This is the first analytical approach to show better ESP collection performance can be achieved at the ratio of wire-wire spacing/wire-plate distance not equal to unity, which has been the industry practice since 1960. The analysis should shed some light on how ESP basic design could be changed and should be especially useful to ESP design professionals and researchers.