Removal of Drops from Liquid-Liquid Dispersions Upon Flow Through Screens

Fibre-packed coalescers are widely employed to remove drops from liquid-liquid dispersions. This work has as its objective a quantitative correlation of drop removal with$ltration variables. Photo-etched screens, which were positioned perpendicular to the flow, served as geometrically defined representations sf jibrous media. Forward-angle light scattering was employed to measure the extent of drop removalfor a variety of screen geometries, flow rates and ph,vsical properties of oil-in-water dispersions. The dispersions, which were prepared by homogenisation, had a narrow range of drop sizes whose average was approximately three microns. The measurements indicate that drop interception, screen geometry, viscous shear and dropJilament adhesion are the main factors which govern drop removal. The redispersion qf the drop phase which had accumulated on the j?laments was generally not observed. The data for the removal of uniform drops by screens with fixed surface energy were correlated with the product of interstitial velocitls, continuous phase viscosity and the projected width of theJilament in the plane of the screen.