Multiphase alternated slug flows: conditions to avoid coalescence and characterization of mass transfer between droplets

Camille Méhault (1) , Laurent Vanoye , Régis Philippe , Claude de Bellefon

1 LGPC - Laboratoire de Génie des Procédés Catalytiques

Alternated slug flow in capillaries is an efficient way to separate droplets with different compositions for applications in various fields. This paper describes how to solve the main issue, i.e. droplets coalescence, by using a gas bubble as a separator and demonstrates quantitatively how the mass transfer between resulting liquid-(gas-liquid)-liquid flow is negligibly impacted by the gas bubble size distribution generated. Thus residence time of up to 30 min could be achieved avoiding coalescence. The conditions to generate and maintain the alternated flow such as the superficial velocities, viscosities and surface tensions, are provided. The mechanism for mass transfer between droplets is shown to occur mainly through the film at the wall of the capillaries explaining the negligible impact of the gas. Mastering such alternated slug flow opens the door for many applications requiring compartmentation of several reactions. 2

Domaines: Génie chimique

Camille Méhault, Laurent Vanoye, Régis Philippe, Claude de Bellefon. Multiphase alternated slug flows: conditions to avoid coalescence and characterization of mass transfer between droplets. Chemical Engineering Journal, 2020, ⟨10.1016/j.cej.2020.127215⟩. ⟨hal-02971352⟩