Absorption of CO2 into aqueous solutions of methyldiethanolamine and activated methyldiethanolamine from a gas mixture in a hollow fiber contactor
Absorption of CO2 into aqueous solutions of methyldiethanolamine and activated methyldiethanolamine from a gas mixture in a hollow fiber contactor
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DOI：
10.1021/ie058023f
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发表时间：
2005-11-23
影响因子：
4.2
通讯作者：
Liu, XD
中科院分区：
文献类型：
--
作者：
Lu, JG;Wang, LJ;Liu, XD
在这项工作中的膜气体吸收（MGA）过程中的CO2捕获CO2/N-2混合气体在室温下进行了评估。采用聚丙烯（PP）中空纤维膜接触器与活化的甲基二乙醇胺（MDEA）水溶液及MDEA水溶液吸收CO2技术相结合进行了实验研究。本研究建立了一个实验室规模的装置，在该装置中，具有CO2负载的溶液能够被热再生为没有CO2负载的溶液并且循环使用。考察了气液流量、膜孔润湿性和CO2液量等操作因素对膜接触器分离性能的影响。比较了活化MDEA和MDEA的吸附性能。建立了膜式气液接触器传质过程的数学模型。实验结果表明，使用改进的烷醇胺如活化的MDEA的膜气液接触器可以完全应用于CO2捕集。低而稳定的液体CO2负荷能够通过热再生控制。活化MDEA的CO2吸收性能明显优于MDEA。活化后的MDEA对CO2的去除率可达99%以上。活化MDEA的平均总传质系数是MDEA的2.25倍。活化剂哌嗪（PZ），即使在活化MDEA中的少量，在MGA中的传质改善中起着显着的作用。模型估计值与实验结果的比较表明，非润湿模式的估计是从实验数据的分歧。考虑到膜的部分润湿，模型模拟与实验数据进行了验证。部分润湿可导致MGA中对传质的显著膜阻力。
A membrane gas absorption (MGA) process was evaluated in this work for CO2 capture from CO2/N-2 gas-mixed streams at room temperature. The experimental study of a polypropylene (PP) hollow fiber membrane contactor in combination with the technique of CO2 absorption into aqueous solutions of activated methyldiethanolamine (MDEA) and MDEA as absorbents was carried out. A laboratory-scale setup, in which the solution with CO2 loading was able to be hot-regenerated into the solution without CO2 loading and used circularly, was established in this study. The effects of a variety of operation factors, such as gas and liquid flow rates, membrane pore-wetting, and liquid CO2 loading, on the separation performance of the membrane contactor were investigated. The absorption performances were compared between activated MDEA and MDEA. A mathematical model was developed to simulate the mass-transfer behavior of the membrane gas-liquid contactor. The experimental results show that the use of a membrane gas-liquid contactor with improved alkanolamines such as activated MDEA can be completely applied to CO2 capture. Low and steady liquid CO2 loading was able to be controlled by hot-regeneration. The CO2 absorption performance of activated MDEA was remarkably better than that of MDEA. The CO2 removal efficiency could reach more than 99% with activated MDEA. The average overall mass-transfer coefficient with activated MDEA was 2.25 times that with MDEA. The activator piperazine (PZ), even with a small quantity in the activated MDEA, plays a significant role in the improvement of mass transfer in MGA. A comparison of model estimations with experimental results indicates that estimations of the nonwetting mode are divaricated from experimental data. Taking partial-wetting of the membrane into account, the model simulation is validated with experimental data. Partial-wetting can result in significant membrane resistance to mass transfer in MGA.