不同間隔層材料對薄膜蒸餾產水之影響研究及應用

Study and Application of Different Material Spacer on Waste water by Air Gap Membrane Distillation

張剛豪(Kang-Hao Chang)

指導教授 ： 游勝傑 ； 王雅玢

中原大學/工學院/環境工程學系/碩士(2019年)

https://doi.org/10.6840/cycu201900823

摘要

隨著社會發展造成的氣候變遷逐年加劇及環境保護意識抬頭，各國政府對於環境保護政策及研究如日中天，水資源管理及回收技術成為政府因應水環境變遷的重點指標，管理層面也慢慢趨向節流及回收的概念，而水回收技術中薄膜蒸餾技術具有良好的回收水質、能源要求相對低及針對鹽類具有高阻抗率等特點，因此本研究因應國際趨勢針對現有的薄膜蒸餾水回收技術進行操作條件優化研究，希望以薄膜蒸餾技術探討廢水應用層面針對水回收技術的可能性。
本研究主要分為三大部分，首先透過建立通量模型的方式確認現有模組操作條件之間的對於產水量及薄膜通量的影響性，本實驗基於已經完成之操作條件研究結果為研究基礎更進一步設定細部的條件變化，探討不同材質間隔層聚丙烯、玻璃纖維、尼龍以及不鏽鋼四種材質的熱傳導係數對於薄膜通量及產水的影響，同時研究在平板板框式薄膜蒸餾模組中模組板框擺放角度形成不同類型間隔式薄膜蒸餾操作模式（模擬LGMD操作模式）對於產水及薄膜通量的比較；接著根據通量模型的最佳操作條件進行廢水實驗，研究最佳操作條件下的廢水實驗中產水量及水質情況；最後針對廢水實驗中的原水、濃縮原水（操作後濃縮廢液）及各時間段之產水水質進行分析，以提供後續實廠應用之參考依據。
實驗結果顯示，在四種間隔層材料中尼龍與不鏽鋼之熱傳導係數高於玻璃纖維及聚丙烯材質，於通量模組中在進料溫度控制在50℃、冷凝端溫度控制在20℃、進料流速在2.4 L/Min的情況下，不鏽鋼及尼龍的薄膜通量分別達到8.749 kg/m2h以及8.735 kg/m2h且高於市售薄膜的通量表現，聚丙烯及玻璃纖維的薄膜通量達到6.307 kg/m2h以及7.447 kg/m2h，因此於後續廢水實驗操作條件中以不鏽鋼及尼龍為材質進行參數實驗；廢水實驗結果中顯示不鏽鋼材質條件在產水方面以平均每小時89.94克優於尼龍材質的平均每小時57.04克，大約是1.58倍，更是薄膜蒸餾通量模組相同條件中最佳通量的95%。
而水質分析結果中顯示化學需氧量的阻抗率為不鏽鋼材質的83.72%及尼龍材質45.03%具有相當大的差異性，電導度讀值為不鏽鋼材質產水12.9μS/cm以及尼龍材質產水62.3μS/cm，其阻抗率依序為99.93%及98.35%同樣是不鏽鋼材質要為優秀，然而在酸鹼度的呈現上兩者水質皆在第三個小時點次進入穩定，產水約在pH=6的水質狀態，濃縮原水約在pH=8的水質狀態，且判斷可能根據實驗時間推移呈鹼性。
因此可以判斷薄膜蒸餾技術在優化間隔層之熱傳導係數後可以有效提升薄膜通量，且在模擬LGMD的操作模式時可以進一步提升薄膜通量及產水，而在廢水實驗中高電導度的廢水可以有效體現薄膜蒸餾技術在電導度的阻抗效果，因此應用於廢水實際應用時建議用於高電導度的廢水，回收的水質也較高。

關鍵字

薄膜蒸餾 ； 間隔層 ； 水回收 ； 廢水應用

並列摘要

As the climate change caused by social development has been intensified year by year and the awareness of environmental protection concept has been arising, governments have been actively and extensively working on environmental protection policies and researches. Water resources management and recycling technologies have become the governments’ key indicators for responding to changes in the water environment. The management level also gradually changes the mainstream to resources saving and recycling from the orientation of application and development, while the membrane distillation in water recovery technology has the advantages of excellent water quality, relatively low energy requirement and high resistance rate for salt. Therefore, this study is based on the international trend to optimize the operating conditions of existing membrane distillation system, and hopes to explore the possibility of water recycling technology in wastewater application.
This study is mainly divided into three parts. Firstly, the influence of the existing module operating conditions on the water production and membrane flux is confirmed by establishing a flux module. Secondly, the parameter of the experiment is based on the former research, then further discuss the results by the detail parameter design for the influence of the heat transfer coefficients of the different gap layer materials of polypropylene, glass fiber, nylon and stainless steel on the flux and water production in the MD system. At the same time, in the flat-panel plate-type thin film distillation module, this study changed the plate frame placement angle to form different types of interval membrane distillation operation modes for the comparison of water production and flux. Then, the wastewater experiment was carried out according to the optimal operating conditions of the flux model to discuss the results of water quantity and quality. Finally, we analyzed the raw water, concentrated raw water and the water quality of each period of time in the wastewater experiment to provide references for the subsequent application in the factory.
The results show that nylon and stainless are relatively high thermal conductivity material than glass fiber and polypropylene in the four gap layer materials that we choose. In the flux module, the temperature is controlled at 50℃ and 20℃ and the flow rate is 2.4L/Min, the flux of stainless steel and nylon groups could reach 8.749kg/m2h and 8.735 kg/m2h, respectively, and were higher than the commercial membrane. Polypropylene and glass fiber groups only reached 6.307 kg/m2h and 7.447 kg/m2h. Therefore, we choose stainless and nylon as the gap layer in the following wastewater experiments to compare the difference. It shows that stainless had better water production in 89.94g/hr than nylon in 57.04g/hr. It's about 1.58 times difference and also equals to 95% of the best flux in the same conditions of membrane distillation flux module.
The water quality analysis showed that the resistance of COD was 83.72% for stainless steel and 45.03% for nylon group. The conductivity reading was 12.9 μS/cm for stainless steel and 62.3 μS/cm for nylon group. The resistance ratio is 99.93% and 98.35%, respectively which has a better performance for stainless steel group. However, in the appearance of pH, the water quality of both groups is stable in the third hour, and the produced water is about pH=6. In the concentrated raw water, pH is about 8, and pH may be alkaline along with the time of the experiment.
Consequently, it can be expected that the thin film distillation technology can effectively increase the flux after optimizing the heat transfer coefficient of the gap layer, and the LGMD operation can improve the film flux and water production rate. The study results exhibit the high conductivity wastewater in the experiment can obviously reflect the advantage of outstanding conductivity resistance in the distillation technology. Therefore, we recommended wastewater with high conductivity is a better target when applying this technology, and the water quality of the recovered water is also remarkable.
Key word: Membrane Distillation, Gap layer, Water recovery, Wastewater treatment application

並列關鍵字

Membrane Distillation ； Gap layer ； Water recovery ； Wastewater treatment application

參考文獻

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