光電廠去光阻(Stripper)排氣時改善白煙形成與冷凝器回收效率提昇之研究

Abstract

摘要 TFT-LCD光電廠與半導體廠中時常為煙囪排放白煙所困擾，一般之作法為透過洗滌塔操作參數調整或串聯洗滌塔(多道處理)，來稀釋或解決煙囪白煙問題，此做法為污染防治設備管末處理，除增加設備建置成本與運轉成本之外，並將空污問題轉成水污問題，又須增加廢水設施處理成本，並非最佳解決方案。 TFT-LCD產業去光阻(Stripper)製程排氣目前大多延用半導體廠常用之冷凝器技術來回收Stripper 。然而TFT-LCD產業隨著玻璃基板之大型化以及製程技術提升等因素，改採用高溫高壓噴嘴噴灑..等物理方式以快速地去除光阻，已有別於半導體製程之浸泡、震盪製程。因高溫高壓噴灑過程中，卻衍生出排氣中有大量煙霧霧滴(Mist)存在，雖經由冷凝器冷凝處理後，排氣管道中仍可明顯看見有白煙產生，與Stripper回收率不佳等問題。 研究後發現，透過源頭防治管理，即在Stripper冷凝器後方安裝高密度除霧器（Demister）,以物理吸附方式,即可有效地攔截收集氣霧狀Stripper；除可增加Stripper冷凝器回收效益外，減少Stripper濕式洗滌塔NaOH加藥量，與降低廢水處理高COD處理負擔，甚至可大輻度降低廢Stripper氣體排放至大氣環境中污染。然而更重要是成本考量，透過此除霧器可回收3,000公升/日stripper，每年至少約可省下6,480萬元，半年內即可回收此設備購置與安裝成本。透過此方案除可增加原物料回收效益，減低後續空污防制設備運轉成本與解決煙囪白煙問題，甚至可降低廢水處理負荷，減少空污防制設備加藥處理費用，其為一舉多得之解決方案，值得執行與推廣。 關鍵字：Stripper製程、高效率過濾器、Stripper冷凝器、煙囪白煙、Demister。

Abstract TFT-LCD optoelectronic plants and semi-conductor plants are often troubled by the chimney white smoke. The general practice is to dilute or solve the issue of chimney white smoke by adjusting the operating parameters of the scrubber or treatment by a series of scrubbers (multi-phase processing and treatment). This approach is the end processing of pollution prevention equipment, which translates the air pollution problem into water pollution. In addition to the increase in equipment building cost and operating cost, it also increases the processing cost of wastewater equipment, and thus is not the optimum solution to the problem. At present, the exhausting of the photoresist stripping process in the TFT-LCD mostly relies on the condenser technology commonly used in semi-conductor plants to recover stripper. However, due to factors such as the increasingly larger-scale glass substrate and improving processing technology of the TFT-LCD industry, physical methods including high temperature, high pressure nozzle spreading are being used to strip photoreist rapidly. Such methods are different from the immersion and vibration process of semi-conductor industry. However, in the high temperature and pressure nozzle spreading process, there will be a large amount of smoke and mist in the exhausted fumes. Despite the condensation process by the condenser, there are problems like apparent white smoke presence in the exhaust gas ventilation pipes, poor stripper recovery rate, etc. The results of this study showed that, by source prevention management, namely, the installation of high density demister at the rear of the stripper condenser, the stripper in mist can be effectively blocked and collected by physical absorption. The proposed method can increase the retrieval efficiency of the stripper condenser, reduce NaOH usage in the stripper wet scrubber and the high COD processing burden of wastewater treatment, and even can considerably reduce the air pollution by the discharge of stripper containing gases.However, cost consideration is also important. The proposed demister can recover 3,000 liter/day stripper and save at least 648, 00,000 NTD each year. The equipment cost can be recovered within half a year. It is a solution to serve multiple purposes, and is worth implementation and promotion. Keywords: Stripper process, high efficiency filter, Stripper condenser, chimney white smoke, demister.