Résumé
Coaxial wire-cylinder electrode arrangements are widely used for the electrostatic precipitation of dust particles contained in flue gases. The aim of this paper was to evaluate a new design, which was expected to increase the particle collection efficiency. The collector electrode of the several models under study consisted of a cylinder with alternate small- and large-diameter sections. In a first set of experiments, the current-voltage characteristics of each model were compared with those obtained for a standard wire-cylinder electrode arrangement, at both polarities of the high-voltage supply, and for three values of the inlet airflow rate, namely, 0, 4.5, and 6 dm(3)/min, with the corresponding air velocities in the large-diameter sections being 0, 6.0, and 8.0 cm/s. A second set of experiments showed that the current density distribution inside the models depends on the geometry of the electrode system but is roughly the same at 4.5 and 6 dm(3)/min. The particle collection efficiency of the different models was evaluated in a third set of experiments, performed with 2-g samples of starch powder, under various operating conditions. Data analysis revealed that the modified precipitators have higher efficiency than the standard model. As expected, for a given geometry of the electrode arrangement, the efficiency was found be lower at higher inlet airflow rates. These findings could serve in the design of new industrial electrostatic precipitators.