Effects of particle space charge and turbulent diffusion on performance of plate-plate electrostatic precipitators

Effects of the particle space charge density and the turbulent diffusion on the collection efficiency of a plate-plate electrostatic precipitator are studied. It is assumed that the precharged monodisperse particles mixed with gas enter the plate-plate electrostatic precipitator. The distributions of electrical potential and particle number concentration and the collection efficiency are obtained by solving the Poisson equation for electrical potential and the modified convective-diffusion model for particle concentration considering the particle space charge. It is observed that the inner electrical potential of the plate-plate electrostatic precipitator is higher than the applied voltage when the particle space charge density is very high. Therefore, the collection efficiency increases for the high turbulent diffusivity but decreases for the low turbulent diffusivity as the particle space charge density increases above the critical length of electrostatic precipitator. Moreover, the particle dispersion overwhelms the turbulent diffusion effect of particles, and consequently the influence of turbulent diffusion on the collection efficiency diminishes as the particle space charge density increases. (C) 1998 Elsevier Science B.V. All rights reserved.