奈米過濾處理模擬電廠廢水之研究

Nanofiltration of the Simulated Effluents from the Power Plant

王可瑄(Ko-Shung Wang)

指導教授 ： 童國倫

中原大學/工學院/化學工程研究所/碩士(2006年)

https://doi.org/10.6840/cycu200600787

摘要

中文摘要
火力發電廠多使用煙氣除硫（flue gas desulfurization，簡稱FGD）洗滌系統以排除鍋爐中之污染物，但經由洗滌系統排放之廢水其組合成份有相當大的變化，因此設計一個符合各種規範的FGD廢水處理系統是極具挑戰性的。基於環境保護、降低能源消耗以及提升經濟效益的需求，建立一套廢水回收處理技術儼然成為一新興技術人員亟求的目標。本研究嘗試圖以奈米過濾方法處理自行配置之FGD廢水，評估以奈米過濾取代原先以FGD廢水處理中之離子軟化槽的可能性。實驗結果顯示指出，當一價離子和二價離子通過濾膜時，後者有明顯的排斥效果。在進料液中提高陰離子的濃度會造成離子排斥效應，因而妨礙陽離子擴散，反之亦然。而有機物質的存在則會影響進料液的pH值，進而造成濾膜中羧基的質子化。而此一性質的改變會降低濾膜中的荷負電量，進而降低離子的立體障礙，導致並且提高流率濾速提升。最後，本研究亦針對以低壓奈米過濾法處理無機鹽類之輸送現象做一理論評估。理論分析顯示：有效電荷密度、膜孔半徑以及離子強度是影響濾膜對一價離子截留率的主要因素。

關鍵字

電廠廢水 ； 奈米過濾

並列摘要

Abstract

Many fossil fuel power plants employ flue gas desulfurization (FGD) using scrubbing systems to remove contaminants from boiler exhaust gases. The waste composition in the effluent from the scrubbing system varies widely, designing an FGD wastewater treatment system that meets regulations can be challenging. Thus, aspirations for new wastewater treatment/recovery processes with environmental friendly technologies, lower energy consumption, and improved economics have emerged. In this study, the simulated FGD effluent from activated carbon column was treated by nanofiltration (NF) process to assess the potential of NF to replace softening column in FGD wastewater treatment process. Experimental results depict that NF membranes notably reject divalent ions. While monovalent ions and divalent ions passing through, the latter had a significant effect on the rejection of NF process. Increase of the concentration of anion in feed solution will results in an ionic exclusion effect and thus retarding cation diffusion, and vice versa to the case of cations. The existence of organic matter may affect the pH value of the feed solution, which will result in protonation of the carboxylic group in the membrane. This change of membrane property will reduce the amount of negative charge of the membrane and caused a reduction of steric exclusion to the ions as well as a increase of flow rate. Finally, the transport parameters of salt in this low-pressure NF process were also evaluated. Theoretical analysis reveals that effective charge density, pore radii and the ionic strength determine the rejection of monovalent ions.

並列關鍵字

Nanofiltration ； Power Plant

參考文獻

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