(539c) Gas- Liquid Flow Hydrodynamics and Mass Transfer in Micro-Packed Beds

Authors: 
Zhang, J., The State Key Laboratory of Chemical Engineering, Tsinghua University
Jensen, K. F., Massachusetts Institute of Technology
In this paper, the hydrodynamics and gas-liquid mass transfer characteristics of gas-liquid two-phase flow in the micro-packed bed were investigated. The hydrodynamics, including pressure drop, residence time distribution and liquid holdup were determined. The effect of gas and liquid superficial velocity, glass bead size, packed bed diameter and liquid property on the hydrodynamics has been studied. The results showed that the pressure drop and liquid holdup in micro-packed beds were higher than that in conventional packed beds due to the effect of capillary pressure. A mathematical model has been developed to describe the hydrodynamics in the micro-packed beds by taking into account the capillary force. The volumetric liquid-side mass transfer coefficients (kLa) was evaluated by the chemisorption of CO2 in methyl diethanolamine water solution. An online measurement method was developed with in-line FTIR, which was used to measure bicarbonate ion concentration to calculate CO2 absorption rate. The influence of gas and liquid superficial velocities, packed bed size and packing particle size on the kLa was examined. The results showed that kLa was in the range of 0.24~0.7 s-1, which is about an order of magnitude than that of conventional trickle bed. An empirical correlation was developed to predict the kLa at different conditions.