The Effect of Charged Granules Agglomerations on the Electric Field Distribution of a Tribo-aero-electrostatic Separator

Recycling of plastics from WEEE requires, first of all, separation on polymer types with various technologies being currently employed for this operation. A new solution, the single-step triboelectrostatic separation, that was developed in recent years consists in a fluidized-bed tribocharging process simultaneous with the separation process. The experimental analysis of plastic granules separation in this type of equipment shows charged granules accumulated in the zone of opposite sign electrode who do not exit the tribo-charging and separation chamber. In order to evaluate the effect of the charged granules on the field distribution two 2D geometries were modelled and the electric field was calculated. The results show that an accumulation of charged granules in the proximity of the separator electrodes leads to a decrease of the electric field intensity, which in extreme conditions can be cancelled or even reversed, with great impact on the quality and quantity of the recovered fractions. The results obtained from these simulations are particularly useful for choosing practical solutions for the construction of the separator.