Liu Ziye, Mu Ling, Feng Chuanyang, Li Xiaofan, Liu Tian, Jiang Xin, Bai Huiling, Liu Xiaofeng
College of Environmental Science and Engineering, Laboratory of Compound Air Pollutions Identification and Control, Taiyuan University of Technology, Taiyuan,030024, China.
College of Environmental Science and Engineering, Laboratory of Compound Air Pollutions Identification and Control, Taiyuan University of Technology, Taiyuan,030024, China; Institute of Nuclear Environmental Science, China Institute for Radiation Protection, Taiyuan,030006, China.
Sci Total Environ. 2024 Oct 20;948:174619. doi: 10.1016/j.scitotenv.2024.174619. Epub 2024 Jul 11.
Although coking process is the important source of polycyclic aromatic hydrocarbons (PAHs) in the environment, the generation and emission of PAHs during this process is unclear. It is crucial to clarify the formation mechanism of PAHs in coal pyrolysis during the coking process for effectively identifying and controlling the emission of these organic pollutants. In this study, the combination of laboratory simulation and field sampling was used to analyze the mechanism of PAHs formation and emission in coking process. The release of PAHs from the pyrolysis process of coal blends used in coking plants was 1778.20 ± 111.95 μg · g, which was much higher than the content of free PAHs in raw coal (76.50 ± 12.46 μg · g). 3-ring PAHs were the most abundant components of free PAHs and pyrolysis-generated PAHs. PAH formation during pyrolysis of coal blends was primarily attributed to the cracking of the macromolecular structure of coal, with minimal influence of free PAHs in blended coal. The emission of PAHs from coal-charging was higher (62.93 ± 17.75 μg · m) than that from pushing of coke (11.79 ± 1.91 μg · m·, PC) and combustion of coke oven gas (5.53 ± 1.20 μg · m, CG), and was mainly related to free PAHs in coal. In contrast, the characteristics of PAHs in the flue gas of PC and CG were similar to those from blended coal pyrolysis. PAHs in fugitive emission from coke oven were primarily affected by flue gas leakage and were mainly related to coal pyrolysis and free PAHs in blended coal.
尽管炼焦过程是环境中多环芳烃（PAHs）的重要来源，但该过程中PAHs的生成和排放情况尚不清楚。明确炼焦过程中煤热解过程中PAHs的形成机制对于有效识别和控制这些有机污染物的排放至关重要。本研究采用实验室模拟与现场采样相结合的方法，分析炼焦过程中PAHs的形成和排放机制。焦化厂使用的混合煤热解过程中PAHs的释放量为1778.20±111.95μg·g，远高于原煤中游离PAHs的含量（76.50±12.46μg·g）。三环PAHs是游离PAHs和热解生成PAHs中含量最高的成分。混合煤热解过程中PAHs的形成主要归因于煤大分子结构的裂解，混合煤中游离PAHs的影响最小。装煤过程中PAHs的排放量（62.93±17.75μg·m）高于推焦过程（11.79±1.91μg·m，PC）和焦炉煤气燃烧过程（5.53±1.20μg·m，CG），且主要与煤中的游离PAHs有关。相比之下，PC和CG烟气中PAHs的特征与混合煤热解过程中的相似。焦炉逸散排放中的PAHs主要受烟气泄漏影响，且主要与煤热解及混合煤中的游离PAHs有关。
