Effects of surfactants on hydrodynamics and mass transfer in a co-current downflow contacting column

• Published in: Chemical engineering research & design Vol. 109; pp. 477 - 485
• Main Authors: Orhan, Ramazan, Dursun, Gülbeyi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2016
• Subjects: Co-current down flow; Gas hold-up; Mass transfer; Surfactant; Co-current down flow; Surfactant; Gas hold-up; Mass transfer
• ISSN: 0263-8762
• DOI: 10.1016/j.cherd.2016.02.030

•The co-current downflow contacting column (CDCC) was used in the experiments.•The effect of surfactant addition on CDC column hydrodynamics was investigated.•Empirical correlations were proposed for evaluating gas hold-up and volumetric mass transfer coefficient.•The average error between the correlation predictions and experimental values were under 10%.
The effects of liquid properties on gas hold-up, bubble formation and mass transfer in a co-current downflow contacting column (CDCC) were investigated using tap water and different types surfactant solutions. The experiments were conducted using various orifice diameters (2,3 and 4mm) and at different superficial gas velocities (0.07−0.188ms−1) and liquid re-circulation rates (3.3−6.67×10−5m3s−1). Gas hold-up and volumetric mass transfer coefficient increased with increasing superficial gas velocity and liquid flow rate. As the surface tension decreased so did the size of the bubbles formed such that low kLa values and higher gas hold-up values were obtained. Empirical correlations were proposed for evaluating gas hold-up and volumetric mass transfer coefficients as a function of liquid kinetic power per liquid volume in the column, superficial gas velocity and relative surface tension using the experimental data obtained for the different types of surfactant solutions. These proposed correlations fit the experimental data of gas hold-up and mass transfer coefficients reasonably well for all gas and liquid flow rates and at orifice diameter used.