| 英文摘要 |
The fine particulate (PM2.5) concentrations of Hsinchu County altered along with season. In spring and winter (during the northeast monsoon), the high PM2.5 pollution episodes occurred because of the abroad long range transport.
In order to understand the PM2.5 composition of combustion sources, we conducted seasonally PM2.5 atmosphere manual sampling and chemical component analysis at Chung Cheng primary school and the wastewater treatment plant. Moreover, the study also established the air mass back trajectory.
The PM2.5 concentrations were 40.1 μg/m3 in spring, 15.1 μg/m3 in winter , 13.3 μg/m3 in autumn and 8.4 μg/m3 in summer sequentially. The average chemical composition of PM2.5 with sulfate being the dominant constituent followed by ammonium and nitrate.
In the study, twelve stationary sources including eight different industries located in Hsin-Chu county were selected for conducting flue gas sampling to determined the chemical and physical particulate characteristics.
The concentrations of PM2.5-filteralbe were about 0.32~8.51 mg/Nm3 for coal-fired boiler, and 3.77~22.32 mg/Nm3 for oil-fired boiler. The emission factors were about 0.009 to 0.111 kg/ton for coal-fired boiler, and about 0.206 to 0.500 kg/kl for oil-fired boiler. The PM2.5 emission concentrations of oil-fired boilers were higher than coal-fired boilers, because the latter were well controlled with BACT.
The percent of PM2.5-condensible to PM2.5 -primary were about 40% to 99.5%, and it increased with the temperature of flue gas.
The proportion of PM2.5 to TSP of coal-fired boiler were 0.46 with fabric filter controlled, 0.23 for ESP controlled, and 0.56 for cyclone controlled.
The proportion of PM2.5 to TSP were 0.4 for oil-fired boiler without PM control device, and 0.27 for glass furnace with ESP controlled.
The composite speciation profile was similar in character to the oil-fired and coal-fired boilers, with carbonaceous aerosols being the dominant constituent followed by sulfate, ammonium and lesser amount of other ions and elements. Metallic elements characteristic species of coal-fired boilers were Fe, Ca, Mg, Na and K; and Al, Fe, Ca, V and Ni for oil-fired boilers.
In this study, mass fraction of elemental carbon, organic carbon and sulfate were determined to be the major component in flue gas of fuel combustion source. Therefore, in order to prevent the PM2.5 generation, the following PM2.5 control strategies for combustion sources were proposed.
1. we should recommend the combustion source to improve the combustion efficiency of boilers to reduce the fossil fuel consumption.
2. We can advise the coal-fired or oil-fired combustion pollution source to select the lower sulfur content fuel or shift to cleaner fuel.
3. We are supposed to promote the oil-fired boiler to setup a PM2.5 control device and to enhance the APCD operation audit of coal-fired combustion process.
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