Influência das cargas eletrostáticas na filtração de partículas em meios filtrantes de fibra de vidro

Abstract

Currently, in the gas filtration processes, the presence of electrostatic charges in the particles has been shown to contribute positively to the performance of the filter medium. Due to its high competitiveness in the market for gas-solid separation equipment, the hybrid filter has shown great benefits, being able to operate with low pressure drop and high collection efficiency for fine particulate matter, increasing the useful life of bags, besides reducing the expenses with energy and maintenance of filtration equipment. Hybrid filters are the combination of two or more gas-solid separation equipment with the aim of improving the gas filtration process. In this purpose, the objective of this work was to evaluate the effect of the electrostatic charge applied on the cement particles, during the formation of the dust cake filtration in a glass fiber filter medium. For this purpose, we investigated the particle size distribution of the cement particles, the specific resistance of the cake and the porosity of the filter cake using the Ergun equation with an electrostatic charge of -1, -2, -4, -10 and -12 kV but just -10 and -12 kV there are corona effect. Images were obtained in a scanning electron microscope (SEM) to determine the penetration of the particles in the filter media, the mean particle diameter and the experimental porosity of the filter cake. For the -1, -2 and -4 kV loads applied to the particles, the specific resistance of the dust cake, the pressure drop as a function of the collected mass and the filtration time were estimated and it was verified that the specific resistance of the dust cake and the pressure drop decreased while the amount of particulate material retained in the filter media and the total filtration time increased. At the tensions of -10 and -12 where the corona effect was active, the electrostatic precipitator retained 89% of the particulate material fed in the process and thus the penetration of the particles in the tissue decreased and the filtration time increased by up to 6 times for a -12 kV curve. The filtration tests showed a positive influence of the electrostatic charge on the cement particles during the formation of the dust cake.