光碟製程中有機廢水及廢溶劑之處理

Treatment of wastewater and waste solvent from CD-R and DVD-R manufacturing process

方贊源

指導教授 ： 林勝雄

元智大學/工程學院/化學工程與材料科學學系/碩士(2004年)

摘要

在目前市面上各式的儲存媒體中，因光碟片具有記錄容量大、體積小、保存壽命長、攜帶方便與成本低廉等特性，因此光碟片儲存媒體的重要性與需求量與日俱增。然而，在生產光碟片的過程中也會伴隨產生大量的有機廢氣及廢液，這些有機污染物質如不妥善作處理，勢必將會對環境造成莫大的傷害。
光碟製程中的記錄層塗佈與洗邊等製程是大量使用及產生有機廢氣及廢溶劑的污染來源。光碟片製造業主要污染物為氟化醇(TFP)、丙酮、乙醇、乙二醇醚、2-丁酮等，其中以醇類為最大宗，醇類中又以氟化醇最難處理。
本論文所探討處理之光碟廠的污染物質主要分為兩類，即含氟化醇的洗滌廢水，及含氟化醇、乙醇、丙酮等有機廢溶劑。針對這兩類不同來源及特性之污染物質探討可行且有效的處理程序。
第一類為含低濃度之氟化醇洗滌廢水。因氟化醇具有高水溶性，在光碟製程中所產生含低濃度的氟化醇廢氣先以氧化洗滌方式作氣液間的反應處理，經過反應後的廢氣達排放標準予以排放，而殘餘的洗滌廢水可藉由高級氧化處理單元後再作重複循環利用。本文即針對濕式洗滌法所產生含氟化醇廢水，探討其配合Fenton氧化法作為氧化處理單元之可行性，其中的主要操作參數包括TFP初始濃度、pH值、反應時間、過氧化氫濃度、亞鐵離子濃度、加藥方式等等。研究中討論各種處理方法及操作參數對處理成效的影響，並以總和(Lumped)反應動力學與通式(Generalized)反應動力學等模式探討Fenton氧化法的機制。經實驗結果顯示可幾乎完全去除廢水中的氟化醇，而廢水COD值亦可符合放流水標準，因此為處理含氟化醇洗滌廢水之可行方法。
第二類為含有高濃度丙酮、乙醇、氟化醇等有機物質之廢溶劑。氟化醇乃屬於高單價的有機溶劑，一般光碟廠會利用互溶性高的有機溶劑，如乙醇、丙酮等將殘餘的氟化醇溶劑作收集，以利後續作分離回收再利用。本文分別採用批次與分段蒸餾的方式作分離氟化醇、回收丙酮、乙醇等溶劑的研究探討。當進行第一段蒸餾後，可收集之冷凝液中的輕沸物丙酮濃度約75%，而第二段的蒸餾則可收集丙酮濃度達93%。此時所回收的冷凝液中所含有的氟化醇濃度已相當稀少，因此有利於後續作更近一歨地分離及回收處理。

關鍵字

Fenton氧化法 ； 蒸餾 ； 廢溶劑 ； 光碟製程 ； 氟化醇

並列摘要

Among the memory storage media available, optical devise is the most popular one due primarily to that it has large capacity, long storage life and stability, good portability and relatively low cost. Hence this device has become more importance and gained increasing demand. However, production of the optical memory device is accompanied by significant amounts of waste organic gases and solution. Proper disposal of these waste gases and solution is essentially a must in order to reduce their negative environmental impact.
The coating step of the CD-R and DVD-R productions is mainly responsible for the generation of the organic waste gases and solvents. Among the various pollutants, tetra-fluoro-propanol (TFP), acetone, ethanol, etc are the major ones and TFP is the one which is most difficult to deal with. The present research focuses on two types of major pollutants. The first is the waste rinsing solution that contains small amount of TFP and the second is the waste solvent which contains, in addition to acetone and ethanol, significant amounts of TFT and other impurities.
The waste rinsing solution was obtained from the packed-bed washing tower in which the waste organic components were removed from the waste gaseous streams. The waste rinsing solution was treated in a batch mode by the Fenton oxidation process in an attempt to remove its TFP and COD simultaneously. Primary operating variables considered in the experimental tests included initial TFP concentration, pH, oxidation time, amounts of H2O2 and FeSO4 and the mode of the reagent addition. Optimal operating variables were empirically determined in the test runs. Test results indicated that over 99% TFT destruction and 80% COD removal could be achieved. Furthermore, lumped and generalized kinetic models were adopted in the work to model the mechanism of the oxidation process.
In the treatment of waste solvent, recovery of acetone and ethanol is the main focus. A simple batch distillation apparatus with a side condenser was designed for this purpose. The experimental tests showed that in a single stage distillation, over 75% of acetone and ethanol can be recovered and the recovered solvent mixture containing negligible amount of TFT can readily recycled for reuse.

並列關鍵字

HASH(0xcacc488)

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