Characteristics of PM2.5 and polycyclic aromatic hydrocarbons emitted from coal combustion and waste incineration processes

• Main Authors: Chia-Ming Lu, 呂佳明
• Other Authors: Moo-Been Chang
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/j7d798

碩士 === 國立中央大學 === 環境工程研究所 === 106 === 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%.