旋轉填充床之疏水性有機揮發物質的質傳研究

Mass Transfer of Hydrophobic Volatile Organic Compounds In a Rotating Packed Bed

劉奕瑩(Yi-Ying Liu)

指導教授 ： 劉懷勝

國立臺灣大學/工學院/化學工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.02066

摘要

本研究為錯流式旋轉填充床內的吸收程序來處理疏水性揮發有機物質。在過去的文獻中，吸收程序通常用水來處理親水性揮發有機物質，因為水是便宜、方便取得且有效的吸收劑。而在處理疏水性揮發有機物質時，水不再為適當的吸收劑；大部分的疏水性吸收劑為高黏度液體，會影響在填充床中的操作，造成溢流現象的產生，而錯流式旋轉填充床中以離心力取代重力，故可以突破高黏度的限制，吸收劑有更多的選擇，亦有更廣泛的氣液操作範圍。故本研究考慮了各疏水性吸收劑的亨利常數、黏度、價格、安全性，選擇了矽油用以吸收本實驗欲處理的疏水性揮發有機物質甲苯、二甲苯。
　　由實驗結果得之，隨著實驗的操作條作轉速、氣液流量增加，會使得質傳效果變好，而氣體進料濃度對於質傳效果的影響較小，質傳係數在這樣的濃度範圍下呈現一穩定值。而在低轉速(800 RPM)與低液體流量(240 mL/min)下，由直接觀察與實驗數據結果可得之，液體在填充床中有分佈不均勻的情形發生，會使得質傳效果下降。矽油在高液體流量與高轉速的操作下，對於甲苯、二甲苯有95%以上的吸收效果，達到可以直接排放的標準，是一安全且有效的處理疏水性揮發有機物質的化工程序。最後，將實驗所得到之質傳係數進行廻歸分析，得到一質傳係數經驗式如下，並且此經驗式可用來估算更廣泛液體黏度範圍中，在錯流式旋轉填充床中的質傳係數。

關鍵字

矽油 ； 甲苯 ； 二甲苯 ； 旋轉填充床 ； 疏水性揮發有機物質 ； 質傳

並列摘要

In this study, absorption process that applies on treating hydrophobic volatile organic compounds (VOCs) in a cross-flow rotating packed bed (RPB) was investigated. In the literature of the past, it was usually used water to treated hydrophilic VOC on absorption process, because water was an inexpensive, available and effective absorber. When treating VOC, water is not more appropriate absorber. Most of hydrophobic absorbers have high viscosities to influence the operation in packed column and cause flooding. In RPB, it replaces gravity with centrifugal force, so it can be operated on a more extensive range of gas and liquid flow rate, and it does not restrict by high viscosity and choice more different absorber. In this study, we pondered over the Henry’s constant, viscosity, cost and safety of absorbers, and finally chose silicon oil to treated hydrophobic VOCs (toluene, xylene) on the absorption process.
According to the experimental results, mass transfer efficiency increased with rotational speed, gas and liquid flow rate. However, the concentration of gas inlet had little influence on mass transfer efficiency. Mass transfer coefficient maintained a constant value on the range of those concentrations. At low rotational speed (800 RPM) and low liquid flow rate (240 mL/min), according to the experimental results and visual observation, there were no well liquid distribution in RPB; it made mass transfer efficiency decrease. Toluene and xylene were absorbed by silicon oil with high liquid flow rates and high rotational speeds; its efficiency exceeded 95% and achieved the standard of direct emission, so this was a safe and efficient chemical engineering process on treating hydrophobic VOCs. Finally, all experimental data were correlated into an empirical formula, and it estimates mass transfer coefficient on an extensive range of liquid viscosity in a cross-flow RPB.

並列關鍵字

Rotating packed bed ； Hydrophobic VOCs ； toluene ； xylene ； Mass transfer ； silicon oil

參考文獻

許宜群 (2004), 錯流式旋轉填充床之特性研究, 台灣大學化學工程碩士論文.

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