| Summary: | 碩士 === 國立中山大學 === 環境工程研究所 === 103 === The Lin-Hai Industrial Complex in Kaohsiung City is one of the largest industrial areas in Taiwan. One of the major air pollution sources is fine particles（PM2.5）emitted from the integrating steel plant. However, the information of fine particles emitted from the stacks of the integration steel plant is rare. Thus, this study aims to sample the fine particulate matter emitted from the stacks of steel plants and further analyze its physical and chemical properties, in order to characterize the elemental indicator(s) for different manufacturing processes. The results would provide valuable emission data to the environmental related governments and research institutes, for establishing air pollution control strategies and identifying potential emission sources. Fine particles are particles suspended in the air, with aerodynamic diameter less than or equal to 2.5 μm, which has become the largest challenge for air pollution abatement. Although Taiwan EPA has already categorized PM2.5 into Ambient Air Quality Standard with national control strategies and projects, Kaohsiung City currently remains the most polluted area in Taiwan, thus significant reduction of PM2.5 emission is highly required, and therefore it is necessary to apply more advanced control strategies that are suitable for local areas.
Better understanding the emission of PM2.5 can be achieved by reviewing previous literature of fine particles emitted from the integrating steel plant, and by collecting the data of chemical properties of fine particles emitted from large stacks of steel plants. This study focused on the analysis of fine particles, referring to “sampling procedure fine particles（PM2.5）emitted from stationary sources for NIEA A212.10B” , issued by Taiwan’s EPA announced (equivalent to US EPA Method 201A) and adapted by US EPA Method 202, gaining better understanding of integrating steel plant.
The concentration of filterable PM2.5 emitted from the stacks of an integrating steel plant ranged from 0.625 to 7.454 mg/Nm3, while that of condensable PM2.5 ranged from 0.127 to 0.276 mg/Nm3. The concentration of PM2.5 from the highest to the lowest levels (filterable and condensable) were as follows: PS11 > PS31 > PS51 > PO13 > PS71 > PB53> PC83 > PP81 > PY55> PR62 > PPC1 > PR21. The highest PM2.5 levels came from sinter plants processes, followed by basic oxygen furnaces, blast furnaces, coke ovens, coal-fired power plant, raw material storage yards, and hot strip mills.
Water-soluble ions of filterable PM2.5 emitted from stacks showed that the highest anion concentration was NO3-, and followed by SO42- and Cl-, while the highest cation was Na+, and followed by K+ and Ca2+. The ratio of equivalent anions and cations (A/C) ranged from 0.69 to 1.69. Metallic elemental analysis showed that the most abundant elements were K and Ca, and followed by Al, Fe, and Mg. Carbonaceous content analysis showed that organic carbon (OC) concentrations were generally higher than elemental carbon (EC). The mass ratio of OC and EC (OC/EC) ranged from 1.08 to 4.89. Furthermore, water-soluble ions of condensable PM2.5 emitted from stacks showed that the highest anion concentration was NO3-, and followed by SO42- and Cl-, while the highest cation was K+, and followed by Na+ and Ca2+. The ratio of equivalent anions and cations (A/C) ranged from 0.70 to 1.59. Metallic elemental analysis showed that the most abundant element was Ca, and followed by Mg, Al, and Fe. Carbonaceous content analysis showed that organic carbon (OC) concentrations were generally higher than elemental carbon (EC). The mass ratio of OC and EC ranged from 1.05 to 4.46.
This study revealed that the highest ionic concentrations of PM2.5 was NO3-, and followed by SO42-. Due to high temperature combustion of the integrating steel plant, fine particles were highly correlated to nitrogen concent of raw materials and fuels. Both raw materials (iron ore, marble, and recycled materials) and fuels (coal and 4-6 grade heavy oil) contain N or S. The impurities can be removed by adding desulfurizer and forming slag,and thus raising the concentrations of SO42-. High concentrations of Cl- and Na+ were caused by the use of recycled materials consisting N and Na compounds from the sinter plant.
Within the steel integrating processes, both filterable and condensable PM2.5 contain higher concentrations of K, Al, and Ca due to the presence of O within the liquid steel during the reduction and refining processes. The addition of deoxidizers caused O to react, resulting in alumina. Metals with low molecular weight are more likely to exist within fine particles, such as K, Al, and Ca, which can be seen as metallic elements emitted from the Integrated Steel Plant.
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