Characteristics of polycyclic aromatic hydrocarbons and their gas/particle partitioning from fugitive emissions in coke plants

摘要

Coking is one of the most important emission sources of polycyclic aromatic hydrocarbons (PAHs) in China. However, there is little information available on the emission characteristics of PAHs from fugitive emission during coking, especially on the specific processes dominating the gas-particle partitioning of PAHs. In this study, emission characteristics and gas-particle partitioning of PAHs from fugitive emission in four typical coke plants (CPs) with different scales and techniques were investigated. The average concentrations of total PAHs from fugitive emission at CP2, CP3 and CP4 (stamp charging) were 146.98, 31.82, and 35.20 μg m~(-3), which were 13.38-, 2.90- and 3.20-fold higher, respectively, than those at CP1 (top charging, 10.98 μg m~(-3)). Low molecular weight PAHs with 2-3 rings made up 75.3% of the total PAHs on average, and the contributions of particulate PAH to the total BaP equivalent concentrations (BaP_(eq)) in each plant were significantly higher than the corresponding contributions to the total PAH mass concentrations. The calculated total BaP_(eq) concentrations varied from 0.19 to 10.86 μg m~(-3) with an average of 3.14 μg m~(-3), and more efficient measures to control fugitive emission in coke plants should be employed to prevent or reduce the health risk to workers. Absorption into organic matter dominated the gas-particle partitioning for most of the PAHs including PhA, FluA, Chr, BbF, BkF and BaP, while adsorption on elemental carbon appeared to play a dominant role for AcPy, AcP and Flu.