Inclined wettable filter for mist purification

Abstract

Agranovski and Braddock [AIChE J. 4 (1998) 2784] investigated a process of filtration of ultra small liquid particles on wettable fibrous filters. They found that liquid droplets captured by a wettable filter spread along the fibres and create a thin liquid film covering each fibre. These films of liquid establish a self-draining, tapered equilibrium flow down the filter. The thickness of the liquid film is an important parameter altering the physical characteristics and performance of the filter. The properties of the film depend on the density, viscosity and amount of liquid present, the physical parameters, wettability and dimensions of the filter and also on the orientation and angle of inclination of the filter. The thickness of the liquid film can be increased by increasing the angle of inclination of the filter and by selecting the orientation. It leads to the possibility of increasing the efficiency of wet filtration without any increase in the amount of irrigating liquid involved. It is especially important for industries where, due to some technological or economical reasons, the amount of fresh irrigating liquid available for the process, is limited. In the current paper, the results of theoretical and experimental analysis of inclined wettable filtration systems are presented and further steps towards industrial design are discussed.