膜接触器吸收二氧化碳过程中的膜润湿研究

Study on the membrane wetting in the process of CO_2 absorption by membrane contactor

自制疏水性聚偏氟乙烯(PVDF)中空纤维膜膜组件,采用二乙醇胺(DEA)溶液为吸收液进行二氧化碳吸收实验,研究了在膜接触器中的微孔膜润湿随操作时间的变化,以及吸收液浓度和温度对膜润湿的影响.实验结果表明,随着吸收过程的进行,膜润湿百分率逐渐增加;膜润湿随着DEA溶液浓度的增大而下降;升高温度促进了微孔膜的润湿.利用微孔膜渗入机理、Fick定律和膜孔径对数分布函数,我们提出了膜吸收过程中膜润湿百分率随时间变化的理论方程,并且对实验数据进行了拟合,得到了较好的拟合效果;同时理论上分析了膜润湿对总传质系数的影响.

The hollow fiber membrane of hydrophobic polyvinylidene fluoride （PVDF） was used to make membrane module to the CO2 absorption,and the diethanol amine （DEA） aqueous solution was applied as absorbent.In this paper,we studied the membrane wetting process in membrane contactor,and the influence factors of concentration of DEA and solution temperature.The experimental results indicate that,the membrane wetness increased with the absorption process; increasing the solution concentration of DEA hindered the membrane wetting; however,rising the solution temperature could accelerate the membrane wetting.According to the kinetics of micropore imbibitions,Fick-law and membrane pores distribution,we put forward a theory equation between the membrane wetness and wetting time,and successfully fitted the membrane wetting results in gas absorptions.Simultaneously,we analyzed the influence of membrane wetting on the mass transfer coefficient in theory.