INFLUENCE OF SURFACTANTS ON ABSORPTION OF CO2 IN A STIRRED-TANK WITH AND WITHOUT BUBBLING

We determined volumetric mass transfer coefficients k(L)a for the abso rption of bubbled and unbubbled CO2 in a stirred tank, with and withou t surfactants in the absorbent liquid. In the absence of surfactants, results obtained under continuous liquid flow regimes agreed closely w ith batch results; accordingly, for convenience, subsequent experiment s with surfactant additives were performed only with continuous liquid how. 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 i s the effective power supplied to the tank, Vis the volume of liquid i n the tank and K depends on surfactant concentration and the bubbling device and increases linearly with the liquid how rate. Surfactant red uced k(L)a by an amount that, to within a 3% error, was proportional t o both the corresponding value of k(L)a in the absence of surfactant a nd the surface concentration of surfactant. (C) 1997 Elsevier Science S.A.