Experimental study of fly ash precipitation in a model electrostatic precipitator with discharge electrodes of different design

The study was inspired by the need to replace the spiked band electrode with another one which would display a higher mechanical strength and a longer service life and would be able to provide similar electric field parameters and similar precipitation efficiency as does the spiked band electrode. A major objective of the study was to investigate the influence of the physicochemical properties (chemical composition, particle size distribution and resistivity) of the fly ash on the collection efficiency. For this purpose, three electrodes with a difference in design were tested. The fly ash was produced by a pulverized-fuel boiler fired with bituminous coal and a lignite-fired fluidized-bed boiler of which flue gas was used. The experiments were carried out under laboratory conditions with a single-stage electrostatic precipitator test facility. The chamber of the experimental setup was made of Plexiglas, with a length of 2 in, a height of 0.45 m and an interelectrode spacing of 0.4 m. The results (gathered in tables and plotted in figures) show how the corona electrode geometry, the physicochemical properties and resistivity influence the collection efficiency under experimental conditions. The highest collection efficiency was obtained with a pipe and double-spike electrode. In the course of the experiment, the N-EHD parameter was established, which is a dimensionless electrohydrodynamic characteristics value, used to describe the dominance of either electrohydrodynamic or viscous forces in a nonconductive fluid. (C) 2003 Elsevier B.V. All rights reserved.