Fugitive Emission of Polycyclic Aromatic Hydrocarbons and Metals in Forming Process in Fastener Manufacturing Industries

• Main Authors: Fang-ying Liang, 梁方熒
• Other Authors: Perng-jy Tsai
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/01628460887503504736

碩士 === 國立成功大學 === 環境醫學研究所 === 96 === This study measured polycyclic aromatic hydrocarbons (PAHs) from flue gas ducts and the workplace environment of a fastener forming precess to characterize their emissions and assess their impacts on ambient environment and workplace workers. PAHs in three types of duct flue gas were collected by using the AST stack-sampling system. Results show that the magnitude as Total-PAHs concentrations in sequence is: forming machine duct (107 �慊/m3) > scrap surge tank duct (53.6 �慊/m3) > product surge tank duct (48.7 �慊/m3). By examining the distribution of particle and gaseous-phase PAHs, we found that Total-PAHs in the three collected ducts were consistently dominated by the former (64.9 -87.7 %). Total-PAHs found in the metal working fluid (MWF) used in the studied forming process (537 mg/kg) was found with a PAH homologue distribution as HMW-PAHs (81.7 %) > MMW-PAHs (14.5 %) > LMW-PAHs (3.85 %). The above results were quite similar to the particle phase: HMW-PAHs (81.5－81.6 %) > MMW-PAHs (13.9－15.1 %) >LMW-PAHs (3.05－4.48 %). PAHs that found in the three types of flue gas duct, suggesting that particle-phase PAHs were resulting from the impaction of MWF associated with the forming process. Total-PAHs emission rates for the three types of flue gas duct were found as: forming machine duct (0.082 kg/year) > product surge tank duct (0.0162 kg/year)> scrap surge tank duct (0.010 kg/year). Based on this, total forming emission for fastener manufactured plant (consisting of 50 forming machines) was estimated as 5.40 kg/year, which is equivalent to the total emissions of 2.51 waste incinerator (capacity: 40 metric tons per day). In workplace, we used a marple cascade impactor for particle size segregating sampler to characterize particle size distributions of both oil mist and Total-PAHs, and IOM personal sampler followed by a XAD-2 sorbent tube to characterize worker exposures. Results show that both oil mists and Total-PAHs were consistently in the form of bi-mode. Oil mist and Total-PAHs concentrations found in the fine mode (0.13 -1.55 �慆) and coarse mode (3.50-50.0 �慆) were 1.36 and 0.300 �慊/m3 , and 5.90 and 3.59 �慊/m3 , respectively. Suggesting that fine mode PAHs play more important roles on particle- phase PAHs exposed to workers. Estimated worker Total-PAHs exposure was found as 26.9 �慊/m3, unlike those found in the dust flue gas, which was dominated by gaseous-PAHs (81.6 %). The estimated excessive cancer risk associated with above exposures was found as 1.92 X 10-5. This study also measured seven kinds of metal elements (Al, Cr, Mn, Mo, Ni, Pb and Zr) in the wire rod. Results show that the Cr had the highest concentration as: forming machine duct (3.14 �慊/m3) > scrap surge tank duct (2.03 �慊/m3) > product surge tank duct (0.20 �慊/m3). Metal elements found in MWFs were not similar to the concentration in stack, Al had the hightest concentration (54.4 �慊/kg) but not the Cr (46.3 �慊/kg), suggesting that the metal elements in stack were majore resulting from the wire rod which Cr has the most composition. Based on this, metal elements emission form fastener manufactured plant (consisting of 50 forming machines) was estimated as Cr (0.168 kg/year), Ni (0.107 kg/year) and Pb (0.015 kg/year), which is equivalent to the total emissions of 1.04, 0.0006 and 0.001 waste incinerator with DSI/ESP (capacity: 40 metric tons per day).In work place, all of the metal elements were below the detection limit.In conclusion, PAHs and metal elements emission from the forming process of the faster manufacture industry has a very limit impact on workers exposures, but was significant for ambient environment suggest that appropriate air pollution control devices should be used in this industry immediately.