Granular bed filtration of a liquid aerosol

Abstract

Liquid aerosols are found in many industrial sectors, particularly in the mechanical industry (oil mists). Granular bed (GB) filtration could be an interesting means for the removal of these liquid aerosols, due to their high storage capacity, robustness and low maintenance requirements. The aim of the study was to establish the filtration performance (filtration efficiency, pressure drop) of a fixed granular bed during filtration and its clogging by a liquid aerosol. Three grades of sand, obtained by sieving 100–200, 200–355 and 355–500 μm and glass beads of 140 μm diameter were used as the granular medium. The evolution of filtration efficiency and pressure drop of the GB was monitored during clogging with a DEHS aerosol of MMAD = 0.7 μm. Our measurements show that the filtration performance of granular beds during clogging was very similar to that observed for fibrous media. The fraction of the GB pore volume occupied by liquid when the drainage plateau is reached was between 28 and 33%. The GB reaches a drainage stage whose pressure drop can be correctly predicted using a model described for fibrous media.