Intensification of nanoparticles collection efficiency in a bubble column

Nanometric particles localized in workplace environments mainly stem from two sources: on the one hand, nanoparticles which are manufactured in more and more industrial applications and on the other hand, ultrafine particles generated by different processes. Fibrous media are the most effective and widely used dedusting techniques to separate ultrafine particles of a carrier fluid. The main disadvantage is the clogging, that induces a pressure drop increase and thus requires a regular cleaning of the media (or its replacement). Based on these observations, this study proposes to investigate the influence of different operating conditions such as the level of trapping liquid, filtration flow rate, bubble size and the presence of beads, on the collection of ultrafine particles in a bubble column. Despite collection efficiencies lower than those of fibrous filters, experimental results show that bubble columns present collection efficiency important when the liquid height is high and bubbling orifices have low diameters. Besides, if gas velocity does not show an important influence on the collection efficiency, the presence of beads in the liquid increases the residence time of the bubbles in the column and thus the collection efficiency.