Hydrodynamics and mass transfer characteristics in gas–liquid flow through a rectangular microchannel

Abstract

Researches on two-phase transfer and reaction processes in microchannnels are important to the design of multiphase microchemical systems. In the present work, hydrodynamics and mass transfer characteristics in cocurrent gas–liquid flow through a horizontal rectangular microchannel with a hydraulic diameter of 667 μ m have been investigated experimentally. Liquid side volumetric mass transfer coefficients were measured by absorbing pure CO 2 into water and a 0.3 M NaHCO 3 / 0.3 M Na 2 CO 3 buffer solution. Interfacial areas were determined by absorbing pure CO 2 into a 1 M NaOH solution. Two-phase flow patterns and pressure drop data were also obtained and analyzed. This paper shows that two-phase frictional pressure drop in the microchannel can be well predicted by the Lockhart–Martinelli method if we use a new correlation of C value in the Chisholm's equation. Liquid side volumetric mass transfer coefficient and interfacial area as high as about 21 s - 1 and 9000 m 2 / m 3 , respectively, can be achieved in the microchannel. Generally, liquid side volumetric mass transfer coefficient increases with the increasing superficial liquid or gas velocity, which can be described satisfactorily by the developed empirical correlations. A comparison of mass transfer performance among different gas–liquid contactors reveals that the gas–liquid microchannel contactor of this study can provide at least one or two orders of magnitude higher liquid side volumetric mass transfer coefficients and interfacial areas than the others.