| 摘要: | 近年來，高科技產業在台灣蓬勃發展，而相關產業大量使用揮發性有機物也對環境造成顯著的影響。目前可用以去除VOCs的方法很多，經焚化後之VOCs可轉變成CO2及H2O(g)等低環境衝擊之氣體，較無後續處理之問題，使得國內主要高科技廠均使用焚化爐處理廢氣。本研究針對台灣某大型CCL廠之三套蓄熱式焚化爐，分別嘗試於高風量高溫度(條件一)、高風量低溫度(條件二)、低風量低溫度(條件三)及低風量高溫度(條件四)下，比較NMHC之去除效率、NOx及SO2之生成量。NMHC的去除效率方面，發現受溫度之影響較大，溫度越高，去除效率較佳。風量(停留時間)之影響較小，但仍可發現風量越小(停留時間越長)時，效率較好。四個測試參數中，效率由高至低分別為「條件一≈條件四>條件三>條件二」。在NOx生成方面，以Thermal NOx及Prompt NOx兩個機制為主，然而RTO#2有來自製程含有N原子鍵結的DMF，使得經過焚化之廢氣，大量生成NOx。若以操作條件來看，當溫度越高，停留時間越久，生成之NOx越高，由高至低分別為「條件四>條件三>條件一>條件二」。在SO2生成方面，來源主要來自低硫鍋爐油之硫份，因此當焚化爐溫度不易靠VOCs燃燒的熱值來維持時，鍋爐油用量則增加，亦使SO2排放量增加，由高至低分別為「條件二>條件三>條件四>條件一」。在RTO之油耗方面，油耗之多寡顯示出進流VOCs燃燒產生之熱值是否適合該操作條件，由高至低分別為「條件二>條件三>條件四≈條件一」；油耗量又會影響尾氣SO2排放，研究結果發現油耗與尾氣SO2之濃度呈現正相關。在操作成本方面，若考慮將初設費用視為折舊攤提費用(分八年攤提)，則A廠三套RTO之年操作維護費用為1865.2萬元；若不考慮攤提費用，則降為975.2萬元。 High-tech industries apply various volatile organic ccompounds (VOCs) in the processes and the emission of VOCs causes serious impact to the environment. Several methods are available to remove VOCs from processes, for example, incineration is a method to convert VOCs to harmless gases including CO2 & H2O(g), which have much less impact to the environment. Nowadays, more and more high-tech companies apply RTO to destory VOCs from waste gas streams. This research is focus on comparison of removal efficiency of NMHC and formation of NOX & SOX with four different operating conditions, condition I: high flowrate with high temperature; condition II: high flowrate with low temperature; condition III: low flowrate with low temperature; condition IV: low flowrate with high temperature, in a Copper Clad Laminate (CCL) plant which has three sets of RTO. The result shows that temperature has great effect on the removal efficiency of NMHC, the higher temperature, the better removal efficiency. The flowrate has less effect on removal efficiency. However, the smaller flowrate (the longer HRT), the higher removal efficiency. The order of the NMHC removal efficiencies achieved with are condition I & IV > condition III > condition II. On the formation of NOX, the thermal NOX and prompt NOX are the major formation mechanisms. Large amounts of NOX were measured in flue gas of RTO#2, because the waste gas stream contains high concentration of DMF. The results also indicate that higher temperature and longer HRT result in greater formation of NOX. The order of NOx formation are condition IV > condition III > condition I > condition II. As for the formation of SO2, the main source of SOX in flue gas comes from fuel oil which contains sulfur. It is necessary to control temperature in RTO by using fuel oil when the combustion heat of VOCs is not enough to maintain pre-set temperature in system. Therefore, SO2 emission increases with increasing of fuel consumption. The condition II has the largest emission, follows by condition III and IV, the condition I has less emission of SO2. The fuel consumption of RTO is related to combustion heat of VOCs. The order of fuel consumptions in RTO are condition II > condition III > condition I & IV. The fuel consumption will affect emission of SO2 in flue gas and SO2 emission is proportional to fuel consumption. The annual operating & maintenance cost of RTOs in plant A is estimated as NT$ 9,752,000. On the other hand, the annual operating & maintenance cost of RTOs in Plant A will be NT$18,652,000 if depreciation and amortization is included. |
