Influence of surfactants on absorption of CO2 in a stirred tank with and without bubbling

Abstract

We determined volumetric mass transfer coefficients k(L)a for the absorption of bubbled and unbubbled CO2 in a stirred tank, with and without surfactants in the absorbent liquid. In the absence of surfactants, results obtained under continuous liquid flow regimes agreed closely with batch results; accordingly, for convenience, subsequent experiments with surfactant additives were performed only with continuous liquid flow. The results of experiments to determine the dependence of k(L)a on stirring rate and the kind of bubbling device were fitted to within a 4% error by expressions of the form k(L)a = K(P(e)/V)0.4 where P(e) is the effective power supplied to the tank, V is the volume of liquid in the tank and K depends on surfactant concentration and the bubbling device and increases linearly with the liquid flow rate. Surfactant reduced k(L)a by an amount that, to within a 3% error, was proportional to both the corresponding value of k(L)a in the absence of surfactant and the surface concentration of surfactant.