| 摘要: | 本研究擇取台灣北部三座含銅污泥處理廠(A、B及C廠)進行排氣中PCDD/Fs及dl-PCBs去除效率及排放特性研究，並探討操作參數及防制設備流程對煙道排氣與飛灰濃度之影響。研究結果顯示，三廠之APCDs均具良好除酸除塵效果，A、B及C三廠煙囪排氣之PCDD/Fs毒性當量濃度分別為0.06、6.57及0.49 ng I-TEQ/Nm3，B廠排放濃度不僅明顯高於其他兩廠，也超出法規規範(0.5 ng I-TEQ/Nm3)，B廠旋風集塵灰、袋式集塵灰、C廠旋窯旋風集塵灰、煉銅爐旋風集塵灰、第一袋式集塵灰及第二袋式集塵灰均大於法規(1.0 ng I-TEQ/g)，屬有害事業廢棄物，須妥善處理， B、C兩廠之防制設備對於dl-PCBs並無明顯去除效果，同源物分佈均以TeCB-77及PeCB-126為主要優勢物種，且均以氣相為主要分佈。去除效率方面，B廠ACI+袋式集塵器僅56.7%的去除效率，大幅低於本研究其他二場與先前文獻，且洗滌塔出現PCDD/Fs質量濃度上升趨勢，同源物分佈發現，三廠大部分以高氯數物種為優勢物種，但三廠分別在半乾式洗滌塔及洗滌塔後發現低氯數物種分佈上升趨勢，氣固相分佈則是通過洗滌塔或袋式集塵器後，氣相分佈明顯有上升趨勢，說明此一階段發生嚴重記憶效應。透過上述結果並比較三廠防制設備配置，本研究認為洗滌塔不適作為最後一道防制設備，並且二燃室需維持穩定使溫度位於再合成溫度區間機會降低，透過A廠半乾式洗滌塔之高去除效率發現，若以洗滌塔等裝置裝設於熱源後，具快速冷卻特性能有效提高去除效率，記憶效應之負影響也因後續還有其他防制設備迎刃而解。;Three copper-containing sludge treatment plants (A, B and C plants) in northern Taiwan were investigated for the removal efficiency and emission characteristics of PCDD/Fs and dl-PCBs. The effects of operating parameters and APCDs processes on PCDD/Fs and dl-PCBs of flue gas and fly ash were discussed.The results show that the APCDs of three plants have good HCl and PM removal efficiencies. The PCDD/Fs TEQ concentrations of the stacks in the three plants A, B and C are 0.06, 6.57 and 0.49 ng I-TEQ/Nm3, respectively. The PCDD/Fs concentration of Plant B is not only significantly higher than two other plants, but also exceeds the regulation (0.5 ng I-TEQ/Nm3). The PCDD/Fs concentration of cyclone ash, baghouse ash of the Plant B and the cyclone ash of the rotary kiln, cyclone ash of the copper smelting furnace, the first baghouse ash and the second baghouse ash of Plant C are all higher than the regulation (1.0 ng I-TEQ/g), and are classified as hazardous wastes and must be properly disposed of. The APCDs of Plant B and C have no obvious removal effect for dl-PCBs, and the homologue distributions are mainly TeCB-77 and PeCB-126, and they are mainly distributed in the gas phase. In terms of removal efficiency, the removal efficiency of PCDD/Fs achieved with ACI+ baghouse of Plant B was only 56.7%, which was significantly lower than the other two plants, and the PCDD/Fs mass concentration increased as flue gas passed through the wet scrubber. The distribution of homologue indicates that most of the three plants were dominated by highly-chlorinated species. After passing through the wet scrubber or the baghouse, the gas phase distribution reveals increasing trend. These results indicate that severe “memory effects” occur at these stages. Through the results and comparing the APCDs of the three plants, this study considers that the scrubber is not suitable as the final APCD, and the combustion chamber needs to be stably operated. It is found quenching mechanism can effectively inhibit PCDD/Fs formation, and the negative effect of the memory effect can be alleviated by the subsequent APCDs. |
