Gas-liquid mass transfer in circular channels under slug flow regime is a function of diffusivity, channel diameter, average velocity (or bubble velocity), gas and liquid slug lengths¹. This paper will discuss gas-liquid mass transfer studies currently being carried out by the Process Intensification and Clean Technology Group using horizontal single circular channels under slug flow regime. Volumetric mass transfer coefficient (k_La) values were obtained from a physical desorption process (water-nitrogen) using horizontal circular channels of varying dimensions (1-4 mm) and for a range of flow ratios. High speed camera (500 frames per second) was used to measure the bubble velocity. Data obtained has been compared with a model based on penetration theory proposed by Kreutzer et al⁴. This investigation is expected to establish evidence for the dependence of gas and liquid slug length on mass transfer rates and compliment previous work reported by Bercic et al.,² and Vandu et al.³

References

1.van Baten, J.M., Krishna, R., 2004. CFD simulations of mass transfer for Taylor bubbles in circular capillaries. Chemical Engineering Science 59, 2535-2545.

2.Bercic, G., Pintar, A., 1997. The role of gas bubbles and liquid slug lengths on mass transport in the Taylor flow through capillaries. Chemical Engineering Science 52, 3709-3719.

3.Vandu, C.O., Liu, H., Krishna, R., 2005. Mass transfer from Taylor bubbles rising in single capillaries. Chemical Engineering Science 60, 6430-6437.

4.Kreutzer, M.T., Kapteijn, F., Moulijn, J.A., Heiszwolf, J.J., 2005. Multiphase monolith reactors: Chemical reaction engineering of segmented flow in microchannels. Chemical Engineering Science 60, 5895-5916.