title: Release behavior and formation mechanism of polycyclic aromatic hydrocarbons during coal pyrolysis.
abstract: Polycyclic aromatic hydrocarbons (PAHs) are major environmental pollutants. They have attracted considerable attention due to their severe potential carcinogenic, mutagenic and genotoxic effects on human health. In this study, five different rank coals from China were pyrolyzed using pyro-probe CDS 5250 and the release behavior of 16 PAHs under different pyrolysis conditions were studied by Gas Chromatography-Mass Spectrometer (GC-MS). The structural characteristics of the five coals were determined by Cross-Polarization/Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS (13)C NMR) spectroscopy, and then the factors influencing the formation of PAHs during coal pyrolysis were discussed together with the coal structural data. It was shown that the amount of PAHs generated during coal pyrolysis was largely related to coal rank and followed the order of medium metamorphic coal > low metamorphic coal > high metamorphic coal. The amount of total PAHs varied as the temperature was increased from 400 °C to 1200 °C, which showed a trend of first increasing and then decreasing, with the maximum value at 800 °C. Moreover, the species of PAHs released varied with pyrolysis temperatures. When the temperature was lower than 800 °C, the small ring PAHs were the most abundant, while the proportion of heavy rings increased at higher temperature. The results indicate that the formation of PAHs during coal pyrolysis depends on the structure of the coal. The species and amounts of PAHs generated during coal pyrolysis are closely related to the contents of protonated aromatic carbons and bridging ring junction aromatic carbons present in the coal structure.
authors.affiliation: State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Shanxi Province and the Ministry of Science and Technology, Taiyuan University of Technology, Taiyuan 030024, China.
authors.forename: Meiqi
authors.initials: M
authors.lastname: Gao
authors.affiliation: State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Shanxi Province and the Ministry of Science and Technology, Taiyuan University of Technology, Taiyuan 030024, China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Shanxi Province and the Ministry of Science and Technology, Taiyuan University of Technology, Taiyuan 030024, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Dong
authors.affiliation: State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Shanxi Province and the Ministry of Science and Technology, Taiyuan University of Technology, Taiyuan 030024, China. Electronic address: lifan66@hotmail.com.
authors.forename: Fan
authors.initials: F
authors.lastname: Li
authors.affiliation: State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Shanxi Province and the Ministry of Science and Technology, Taiyuan University of Technology, Taiyuan 030024, China.
authors.forename: Kechang
authors.initials: K
authors.lastname: Xie
mesh_terms: D002244:Carbon / Q000737:chemistry; D002273:Carcinogens / Q000032:analysis; D002681:China; D003031:Coal / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*
chemical_list: D002273:Carcinogens; D003031:Coal; D046911:Macromolecular Substances; D011084:Polycyclic Aromatic Hydrocarbons; D002244:Carbon
keywords: CP/MAS (13)C NMR; Coal pyrolysis; Coal rank; PAHs; PY-GC/MS