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摘要
The analytical solutions for calculating the average wetting ratio, < x*>, for gas-liquid membrane contacting process based on log-normal and normal distribution functions have been developed. By using the membrane characteristics, liquid absorbent properties and operating conditions, the average wetting ratio is determined analytically. The overall mass transfer coefficient (KG) corresponding to the average wetting ratio is also calculated. Due to the pressure drop of liquid flow in the fiber, the operation mode would be changed along the fiber and six possible situations of operation cases are observed. In addition, the proposed calculation can predict the fiber lengths that are completely wetted, partially wetted and are completely dry. In order to verify the proposed calculation, the experiments of CO2 absorption from the gas mixture (CO2-N-2) by polyvinylidenefluoride (PVDF) hollow fiber membrane contactor using water and monoethanolamine (MEA) as the absorbents were performed at various inlet liquid pressures (P-L0) and liquid velocities. The results obtained from the experiments were reported in term of overall mass transfer coefficient and were validated with those obtained from the proposed calculations. It reveals that calculation based on log-normal distribution shows a better fit with the experiments compared to that based on normal distribution at all operating conditions indicating that the membrane pore structure can be described better using log-normal distribution function. In addition, the calculated average wetting ratio based on log-normal distribution function greed well with that obtained from the numerical model proposed in the literature.
- 出版日期2013-2-15
