| 摘要: | 本研究探討中部一座木屑鍋爐廠之操作條件對戴奧辛排放特性及生成潛勢之影響，調查其物種分布特性，並蒐集焚化爐、中小型焚化爐、電弧爐、二次銅冶煉爐及木屑鍋爐等固定污染源之煙囪煙道氣戴奧辛排放數據，彙整其戴奧辛同源物種分布特性加以比對檢視，觀察相同之處。結果顯示木屑鍋爐第一次採樣及第二次採樣煙囪煙道氣戴奧辛濃度分別為2.39 ng/Nm3及6.53 ng/Nm3其毒性當量分別為0.21 ng I-TEQ/Nm3及0.17 ng I-TEQ/Nm3，兩次採樣之毒性當量濃度目前以我國中小型焚化爐每小時四公噸以下的標準視均符合法規標準，但未來若以中小型廢棄物焚化爐煙道戴奧辛 (11%氧含量校正)或鍋爐空氣污染物(6%氧含量校正)排放標準審視本廠之戴奧辛排放濃度，仍須進一步改善戴奧辛濃度。在排放係數上，1號及2號鍋爐分別為152及184 μg I-TEQ/ton，高於其他行業之排放係數，顯示在木屑鍋爐之戴奧辛排放不容忽視。同源物種方面在飛灰及煙道氣皆以1,2,3,4,6,7,8-H7CDF、1,2,3,4,6,7,8-H7CDD 及 O8CDD為優勢物種。另外搜集了29廠不同熱處理程序之煙道氣戴奧辛數據與本研究之木屑鍋爐進行物種分布比對及探討，發現大多數排放源之戴奧辛物種分布以1,2,3,4,6,7,8-H7CDF、O8CDF、1,2,3,4,6,7,8-H7CDD及O8CDD為主要優勢物種，少部分排放源則分布較為複雜，且高低氯數佔比相當。PCA分析結果將戴奧辛物種分布相似之污染源聚集一群，暸解在熱處理程序雖有不同，但鍋爐後端防制設備及操作條件能有效去除戴奧辛時，其物種分布為相似的，且多以高氯數之DD/DF為優勢物種。;This study investigates the characteristics of PCDD/Fs emission from a wood chip boiler. It also investigates the congener distribution via collection of PCDD/F emission data from MSWI, small and medium-sized incinerators, and electric arc furnace, secondary copper smelting furnace and wood chip boilers. The results show that the concentrations of dioxin in the flue gas of the first sampling and the second sampling of the wood chip boiler are 2.39 ng/Nm3 and 6.53 ng/Nm3, respectively, and the toxic equivalents are 0.21 ng I-TEQ/Nm3 and 0.17 ng I-TEQ/Nm3, respectively. The TEQ concentrations of PCDD/Fs measured at the stack are lower than the emission limit (0.5 ng I-TEQ/Nm3). In terms of emission factor, No. 1 and No. 2 boilers are 152 and 184 μg I-TEQ/ton, respectively, which are higher than the emission factors of other thermal processes, indicating that the dioxin emission in wood chip boilers cannot be ignored. In terms of homologous species, 1,2,3,4,6,7,8-H7CDF, 1,2,3,4,6,7,8-H7CDD and O8CDD are the dominant congeners in fly ash and flue gas. In addition, the dioxin emission data of 29 plants with different thermal processes were collected and compared with the wood chip boilers in this study. It was found that 1,2,3,4,6,7,8-H7CDF, O8CDF, 1,2,3,4,6,7,8-H7CDD and O8CDD are the dominant congeners for most plants studied, and a small number of plants are more complex in distribution, and the proportion of high and low chlorine numbers is equivalent. In the PCA analysis, most pollution sources with similar dioxin congener distribution were gathered into a group. It is understood that although the thermal processes investigated are different, as long as the APCDs adopted can effectively remove dioxin from gas streams, the distribution of congener will be very similar. |
