| 摘要: | 國內外研究顯示空氣中細懸浮微粒會導致循環系統和呼吸系統方面的健康危害，尤其是粒徑小於2.5 微米的細微粒(PM2.5)被人體吸入後會深入支氣管，干擾肺部的氣體交換，超細微粒甚至可通過支氣管和肺泡進入血液，另外多種有害空氣污染物如多環芳香碳氫化合物及其他空氣污染物等，皆可能附著於細懸浮微粒上，隨血液進入人體循環，對人體健康造成顯著危害。為進一步維護民眾健康及生活環境品質，針對環境細懸浮微粒中 PAHs 及其他空氣污染物分佈特性進行調查實屬必要。本研究已針對本土大型燃煤電廠(A廠)、小型燃煤鍋爐(B廠)及都市廢棄物焚化爐(C廠)完成PM2.5及PAHs之檢測分析作業。A廠煙囪排放之FPM2.5 (0.45 mg/Nm3)明顯低於B廠(1.91 mg/Nm3)之排放，C廠煙囪排放之FPM2.5濃度1.93 mg/Nm3，數據結果得知A廠BH+SWFGD對於FPM2.5去除效率高達99.83%。
PM部分，A廠袋式集塵器(BH)入口濃度高達4,923 mg/Nm3，FPM2.5僅占PM的5.38%，BH+SWFGD對於PM之去除效率達99.98%，而B廠於煙囪檢測之PM濃度為2.55 mg/Nm3，C廠ESP入口、SCR入口及煙囪PM濃度分別為2248、2.47及2 mg/Nm3，C廠之ESP+WS對PM之去除效率達99.91%，本研究結果顯示ABC三廠之CPM濃度均大於FPM2.5及PM濃度，A廠之BH+SWFGD對CPM之去除效率僅38.3%。金屬元素部份，B廠FPM2.5所分析之金屬元素中以Na、Ca、Mg及Fe占比較高，而B廠FPM之水溶性離子以SO42- 佔比最高(606-1279 μg/m3)，其次則為NH4+(191 – 475 μg/m3)。 A廠煙囪排氣24種gas-phase PAHs濃度介於6.93~5297 ng/Nm3，solid-phase PAHs則介於0.40-9.45 ng/Nm3，BH inlet之24種gas-phase PAHs 濃度介於151-50239 ng/Nm3，solid-phase PAHs濃度介於39.1-832 ng/Nm3，而B廠PAHs亦主要分佈於氣相，24種 gas-phase PAHs 濃度遠高於 solid-phase PAHs。A廠BH+SWFGD對於固相PAHs之去除效率平均達98.59%，但對於氣相PAHs表現較差，C廠ESP入口之氣固相PAHs總濃度分別為40862及145 ng/Nm3，SCR入口分別為6.11及7882 ng/Nm3，而煙囪排氣濃度僅3.6及1560 ng/Nm3，數據顯示ESP+WS對於24種PAHs去除效率介於30.35-98.43%，而SCR的去除效率則介於30.87-88.28%。
;It is well known that particulate matter (especially PM2.5) causes adverse effects on human health. Besides, toxic air pollutants such as polycyclic aromatic hydrocarbons (PAHs) may be attached to particulate matter. In this study sampling and analysis of PM and PAHs emitted from one coal-fired power plant (plant A), one coal-fired boiler (plant B) and one MWI (plant C) are conducted. The concentration of filterable particulate matter (FPM2.5) emitted from plant A (0.45 mg/Nm3) is significantly lower than that from plant B (1.91 mg/Nm3). The concentration of plant C is 1.93 mg/Nm3. In plant A, the removal efficiency of FPM2.5 achieved with the APCD (baghouse and seawater flue gas desulfurization) reaches 99.83%. The PM concentration measured at BH inlet of plant A is 4,923 mg/Nm3 and FPM2.5 accounts for only 5.38% of PM. the removal efficiency of PM achieved with the APCD (baghouse and seawater flue gas desulfurization) reaches 99.98%. For plant B, PM concentration of stack gas is 2.55 mg/Nm3 and FPM2.5 accounts for 75% of PM. Moreover, concentration of CPM is higher than FPM2.5 and PM in three plants. It’s worth noting that the removal efficiency of CPM achieved with BH+SWFGD in plant A is 38.3%, which is significantly lower than that of FPM2.5 (99.83%) and PM (99.98%). Besides, 24 gas-phase PAHs and solid-phase PAHs concentrations emitted from plant A are 20.3-34.0 μg/Nm3 and 111-137 ng/Nm3, respectively. The removal efficiency of BH+SWFGD for solid-phase PAHs is 98.59%. but for gas-phase PAHs is lower than solid-phase. Relatively, plant B emits more gas-phase PAHs (35-50 μg/Nm3) and solid-phase PAHs (156-285 μg/Nm3) if compared with plant A. Toxic PAHs are dominant in gas phase for three plants. This study also evaluates the emission factors of PAHs and FPM2.5 for both plants. For plant A, the average emission factors of PAHs and FPM2.5 are 316 μg/kg-coal, 5.25 μg/kg-coal, respectively. For plant B, average emission factors of PAHs and PM2.5 are 382 μg/kg-coal and 16 μg/kg-coal, respectively. As a result, plant A emits less FPM2.5 and PAHs due to higher combustion efficiency and better air pollution control devices. The concentrations of gas and solid phase PAHs at the ESP inlet of Plant C are 40862 and 145 ng/Nm3, respectively, and the SCR inlets are 6.11 and 7882 ng/Nm3, respectively. The concentration of stack are 3.6 and 1560 ng/Nm3. The removal efficiency of PAHs achieved with ESP+WS is between 30.35-98.43%, and that achieved with SCR is between 30.87-88.28%. |
