Chan Zhe Phak, Li Lin, Kang Guodong, Ab Manan Norfaizah, Cao Yiming, Wang Tonghua
School of Chemical Engineering, Dalian University of Technology, Dalian 116023, China.
PETRONAS Research Sdn Bhd, Bangi 43000, Malaysia.
Membranes (Basel). 2020 Dec 9;10(12):407. doi: 10.3390/membranes10120407.
Water condensation is a possible cause of membrane wetting in the operation of membrane contactors, especially under high-temperature conditions. In this study, water condensation in pores of polytetrafluoroethylene (PTFE) hollow fiber membranes was investigated during high-pressure CO absorption around 70 °C. It was found that the liquid accumulation rate in the treated gas knock-out drum was constant during continuous operation for 24 h when all experimental conditions were fixed, indicating a stable degree of membrane wetting. However, as the operating parameters were changed, the equilibrium vapor pressure of water within membrane pores could change, which may result in a condensation-conducive environment. Water condensation in membrane pores was detected and proven indirectly through the increase in liquid accumulation rate in the treated gas knock-out drum. The Hagen-Poiseuille equation was used to correlate the liquid accumulation rate with the degree of membrane wetting. The degree of membrane wetting increased significantly from 1.8 × 10 m to 3.9 × 10 m when the feed gas flow rate was reduced from 1.45 kg/h to 0.40 kg/h in this study due to water condensation in membrane pores. The results of this study provide insights into potential operational limitations of membrane contactor for CO absorption under high-temperature conditions.
在膜接触器运行过程中，水冷凝是导致膜润湿的一个可能原因，尤其是在高温条件下。在本研究中，对聚四氟乙烯（PTFE）中空纤维膜在70℃左右的高压CO吸收过程中的孔内水冷凝进行了研究。发现在所有实验条件固定的情况下，连续运行24小时期间，处理后的气体分离罐中的液体累积速率是恒定的，这表明膜润湿程度稳定。然而，随着操作参数的变化，膜孔内水的平衡蒸气压可能会改变，这可能导致有利于冷凝的环境。通过处理后的气体分离罐中液体累积速率的增加间接检测并证实了膜孔中的水冷凝现象。使用哈根-泊肃叶方程将液体累积速率与膜润湿程度关联起来。在本研究中，当进料气体流速从1.45 kg/h降至0.40 kg/h时，由于膜孔中的水冷凝，膜润湿程度从1.8×10⁻⁶ m显著增加到3.9×10⁻⁶ m。本研究结果为高温条件下CO吸收的膜接触器潜在运行限制提供了见解。
