Absorption of CO2 into Aqueous Solutions of Methyldiethanolamine and Activated Methyldiethanolamine from a Gas Mixture in a Hollow Fiber Contactor

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• 作者：Jiangang Lu ; Lianjun Wang ; Xiuyun Sun ; Jiansheng Li ; and Xiaodong Liu
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2005
• 出版时间：November 23, 2005
• 年：2005
• 卷：44
• 期：24
• 页码：9230 - 9238
• 全文大小：149K
• 年卷期：v.44,no.24(November 23, 2005)
• ISSN：1520-5045

文摘

A membrane gas absorption (MGA) process was evaluated in this work for CO₂ capture fromCO₂/N₂ 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 intoaqueous solutions of activated methyldiethanolamine (MDEA) and MDEA as absorbents wascarried out. A laboratory-scale setup, in which the solution with CO₂ loading was able to behot-regenerated into the solution without CO₂ loading and used circularly, was established inthis 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 membranecontactor were investigated. The absorption performances were compared between activatedMDEA and MDEA. A mathematical model was developed to simulate the mass-transfer behaviorof the membrane gas-liquid contactor. The experimental results show that the use of amembrane gas-liquid contactor with improved alkanolamines such as activated MDEA can becompletely applied to CO₂ capture. Low and steady liquid CO₂ loading was able to be controlledby hot-regeneration. The CO₂ absorption performance of activated MDEA was remarkably betterthan that of MDEA. The CO₂ removal efficiency could reach more than 99% with activatedMDEA. The average overall mass-transfer coefficient with activated MDEA was 2.25 times thatwith 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 modelestimations with experimental results indicates that estimations of the nonwetting mode aredivaricated from experimental data. Taking partial-wetting of the membrane into account, themodel simulation is validated with experimental data. Partial-wetting can result in significantmembrane resistance to mass transfer in MGA.