揮發性有機物質之薄膜吸收去除技術

Absorption Removal of Volatile Organic Compounds from Gaseous Streams in Membrane Contactors

蕭嘉筠(Shiaw Chia Yu)

指導教授 ： 莊瑞鑫

元智大學/工程學院/化學工程與材料科學學系/碩士(2000年)

摘要

本論文主要討論在中空纖維管束中，以液相吸收劑去除揮發性有機物質( VOC )之質傳，中空纖維所使用之材質為聚丙烯( Polypropylene ) 疏水性薄膜，吸收劑選用價格低廉並容易取得之矽油 ( Silicone oil )， VOC 選用較常見且毒性較低之丙酮及甲醇。進料氣體流速為2.1~10.4 cm/s，液體流速為0.6~5.8 cm/s，甲醇與丙酮進料濃度為500 ppmv及1600 ppmv。
由實驗結果得知，在氣體流速2.1 cm/s 及液體流速5.8 cm/s，其去除效率最高，丙酮可達99%以上，甲醇可達95%以上，而且VOC初濃度越高，吸收效果越好。將實驗之操作變數代入中空纖維的理論質傳模式，其中包括液相擴散、氣相擴散及薄膜內擴散等，得知由於液相流速造成的影響不大，證明氣相有較大的質傳阻力。再者我們需要在最差的流速 (氣體流速10.4 cm/s 及液體流速0.6 cm/s) 進行回收，因其回收率與最佳條件比較之下相差25 %~45 %，所以需要達到相同的效率，並將吸收液回收使其可循環使用以符合經濟效益。

關鍵字

揮發性有機物質 ； 氣相 ； 吸收 ； 去除 ； 中空纖維薄膜接觸器

並列摘要

In this paper volatile organic compounds ( methanol and acetone ) were removed by absorption in hollow fiber membrane modules. In these experiments, the hollow fiber membrane used was made the microporous polypropylene. Because of low cost and easy availability, silicone oil was chosen as absorbent. The feed gas flow rate was in the range 2.1~10.4 cm/s, and liquid flow rate was in the range 0.6~5.8 cm/s. The inlet methanol and acetone concentration were 500 and 1600 ppmv, respectively。
The experimental results showed that, at the gas flow rate of 2.1 cm/s and liquid flow rate of 5.8 cm/s, removal efficiencies of acetone and methanol were reached 99% and 95%, respectively. The higher the VOC inlet concentration, the greater the absorption efficiency. From the resistance-in-series theory of mass transfer, (the gas film diffusion, liquid film diffusion, and membrane diffusion) the results indicated that the effect of liquid-film diffusion was negligible and the effect of gas-film diffusion was significant. Furthermore, the removal efficiency at a gas flow rate of 10.4 cm/s and a liquid flow rate of 0.6 cm/s was from 25% to 45%, which was less than those obtained under other conditions. The absorbent could be easily regenerated by adding an extra membrane module.

並列關鍵字

HASH(0x8c946f8)

參考文獻

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