| 摘要: | 台灣都市廢棄物焚化爐每年排放大量底灰及飛灰至環境中，其排放量高達1,200,000 至 1,300,000 噸/年，而飛灰因含有高濃度之氯離子、重金屬及有機污染物(如：戴奧辛、多氯聯苯、多氯萘及多環芳香烴)被視為有害廢棄物，為達到台灣環保署提倡之「零排放政策」，廢棄物焚化爐排放飛灰之再利用技術實有研究價值，過去文獻顯示戴奧辛於350oC缺氧條件下，去除效率可達95%，然而於此熱裂解的過程可能生成其他有機污染物，因此，本研究於飛灰熱裂解測試之前，將先以水洗方式洗出飛灰中氯離子，並以飛灰及煙道氣中之戴奧辛、多氯聯苯、多氯萘及多環芳香烴探討去除效率及機制，此外，本研究將加入以鈀金屬為基底之觸媒於熱裂解反應中，以利降低熱裂解反應溫度(<350oC)、增加戴奧辛去除效率及降低其他有機污染物生成可能性。然而由於觸媒於熱裂解反應之戴奧辛去除機制十分複雜，故本研究將藉由模擬及計算之結果，提出適當戴奧辛破壞機制之假設。藉由了解觸媒熱裂解之破壞戴奧辛機制後將調整操作溫度為200oC且戴奧辛去除效率可達95%。為符合零廢棄政策，本研究將單載磁性氧化鐵於鈀觸媒並建立連續式熱裂解系統， 將觸媒回收再利用，以符合環境工程應用之潛力。 ;The amount of bottom ash (BA) and fly ash (FA) released from all municipal solid waste incinerators (MSWIs) in Taiwan is between 1,200,000 to 1,300,000 tons/year. FA is classified as hazardous waste because it contains high concentrations of chloride, heavy metals and organic pollutants (PCDD/Fs, dl-PCBs, PCN and PAHs). To attain the target of “zero waste policy” enacted by Taiwan EPA, recycle of FA from MWIs should be conducted. Previous studies indicate that 95% of PCDD/Fs in fly ash can be removed at 350oC under oxygen-deficit condition. However, formation of other organic pollutants is observed in the exhaust gas of the pyrolysis system. In this study, FA will be pre-washed to reduce chloride content before being treated with catalytic pyrolysis and PCDD/Fs, dl-PCBs, PCN and PAHs concentrations in fly ash and exhaust gas will be determined. Moreover, different palladium (Pd)-based catalysts will be added to the pyrolysis process in in-situ and ex-situ system at a temperature lower than 350oC to enhance the PCDD/Fs destruction efficiency and reduce the formation of organic pollutants formation in the exhaust gas. The mechanisms for removing PCDD/Fs in the catalytic pyrolysis treatment system are complicated. Therefore, this study is expected to propose appropriate |
