Influência das condições operacionais na formação e remoção de tortas de filtração de gases

Abstract

The present work aims to evaluate the influence of some operational variables on the filtration process and cake detachment, and also the patchy cleaning phenomenon. The studied conditions were maximum pressure drop, 20, 40 and 60 cmc.a., filtration velocity, 5 and 10 cm/s, cleaning velocity, 10 and 15 cm/s and thickness of the cake. Phosphoric rock dust with Stokes diameters of 4,5 µm was used as powder material. The filter medium used was acrylic, polyester and polypropylene needlefelt. To characterize the cleanness of the fabric, it was used the technique to take a photograph of the filter after each cycle of cleanness, getting images of the partial detachment of the cake. These images of cycles 1, 2, 3, 5 and 10 had been studied and analyzed through analytical software of images, the Image-Pro Plus. The efficiency of regeneration and the size of the regenerated areas of the filter had been analyzed. The results showed that the residual pressure drop was higher for thicker cakes. The higher cleaning velocity was not necessarily the one that offers better cake removal. Concerning the patchy cleaning phenomenon, total area removed did not present a defined behavior with the number of cycles. The results also showed that acrylic needlefelt is the best one to this process. This filter medium requires regeneration less frequently as it presents a lower pressure drop tax. As consequence the process is more economic and the filter medium can me used for longer periods of time.