中空纤维致密膜基吸收法在CO2脱除中的应用

摘要

In order to investigate the application potential of hollow fiber membrane contactors, a commercial nonporous polyimide hollow fiber membrane contactor (φ200) was tested by using tap water and seawater as absorbents to separate the CO2 from the gas mixture of CO2 and N2. The effects of liquid flow rate, liquid pressure, gas flow rate and gas pressure on the removal efficiency and overall mass transfer coefficient of CO2 were investigated. The experimental results indicate that the membrane resistance and liquid film resistance control the mass transfer when tap water and seawater are employed as absorbents. Furthermore, the removal efficiency is enhanced when the liquid/gas flow rate ratio increases. The nonporous hollow fiber contactor could perform a high CO2 removal with efficiency over 70%by optimizing the operation conditions. Finally, a stable operation process was achieved. This smooth mass transfer process indicates that the nonporous hollow fiber membrane eliminates bubbling problem and weeping problem that are frequently encountered in microporous hollow fiber contactor. Therefore, the non-porous hollow fiber contactor used in this experiment has great potential for application as a gas-liquid contactor.%　　以商业φ200聚酰亚胺中空纤维致密膜大组件为接触器，淡水和海水为吸收剂，进行了CO2/N2混合气中CO2的脱除实验。考察了气液相压力和流量对CO2脱除率和过程总传质系数的影响。结果显示，液相压力对膜接触器的影响不大，而加大液/气相流量比可以提高CO2的脱除效率，通过控制操作条件可使膜接触器的CO2脱除率在70%以上。实验过程中，气液两相压力可在较宽范围内独立操作，且无鼓泡和漏液现象发生。研究表明中空纤维致密膜基接触器在CO2气体分离领域具有很好的应用潜力和前景。