Residence Time Distribution Analysis of a Hollow-Fiber Contactor for Membrane Gas Absorption and Vibration-Induced Mass Transfer Intensification

The relationship between the flow conditions and the mass transfer in a hollow-fiber membrane contactor was quantitatively correlated by coupling a residence time distribution (RTD) method with a multicontinuous stirred tank reactor model (mCSTR). A vibration technique was applied to manipulate and intensify the mass transfer performance of the hollow-fiber contactor (HFC). Absorption behaviors of CO2 in deionized water were investigated as a model system. The effects of liquid feeding velocity, vibration direction and frequency, operating modes, and packing density on the flow conditions and mass transfer performance were investigated and quantitatively examined by the RTD analysis. The results indicated that the flow conditions as well as the mass transfer performance can be greatly improved at a low liquid-phase velocity or a high packing density. Similarly, the mass transfer intensification was more remarkable, when the absorbent flowed through the shell side of HFC, or the vibration and flow directions were vertical. The mass transfer coefficients obtained from the RTD-mCSTR model showed good agreement with those obtained from the experiments. It appeared that the vibration technique was a powerful method to improve the flow conditions and greatly enhanced the mass transfer performance.