Intensified biogas purification in a stirred tank

The present study aims at intensifying the absorption of carbon dioxide in aqueous phases. For this purpose, a second immiscible liquid phase is used to improve the mass transfer of carbon dioxide in water. Absorption measurements are carried out in a stirred cell by online infrared monitoring of the output carbon dioxide concentration. As dispersed phase, 1-octanol shows an improvement in mass transfer whereas colza oil retards it. Toluene has no significant effect in the range of concentrations investigated. Mass transfer coefficients are determined using a chemical method. Nevertheless, the variety of behaviors could not be explained simply by solubility or variation of mass transfer coefficients. In order to understand the complex gas–liquid–liquid interactions and deduce the mass transfer mechanism between these three phases, surface and interface tension measurements and direct observation of bubbles and droplets are also carried out.