Wang Chunyan, Du Yuhong, Yan Bo, Dong Yonggang, Zhao Zhihui, Shen Jinchao, Guo Mengxia, Zhang Zhaochi
Hebi Institute of Engneering and Technology, Henan Polytechnic University, Hebi, 458000, Henan, People's Republic of China.
College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China.
Sci Rep. 2024 Apr 12;14(1):8522. doi: 10.1038/s41598-024-59098-0.
To study the total particulate matter (TPM) in flue gas emitted by coking plants, a sampling system that could be used to collect filterable particulate matter (FPM) and condensable particulate matter (CPM) was designed and developed based on Method 202 recommended by the U.S. Environmental Protection Agency in 2017 and HJ 836-2017 issued by China. Using this system, FPM and CPM in flue gas emitted by four coking furnaces named A, B, C, and D were tested in China. Further, 9 water-soluble ions, 20 elements, and organic matter present in the CPM were simultaneously examined to determine their formation mechanisms. Statistical data suggested that the FPM emission level in the coking flue gas was low and the average mass concentration was less than 10 mg/m. However, with high CPM and TPM emission levels, the TPM mass concentrations of A, B, C, and D were 130 ± 11.1, 84.4 ± 6.36, 35.1 ± 17.0, and 63.8 ± 13.0 mg/m, respectively. The main component of TPM was CPM, and the average mass concentration of CPM accounted for 98%, 95%, 68%, and 95% of TPM in furnaces A, B, C, and D, respectively. Water-soluble ions were the important components of CPM, and the total concentration of water-soluble ions accounted for 70%, 87%, 42%, and 66% of CPM in furnaces A, B, C, and D, respectively. Toxic and harmful heavy metals, such as Mn, Cr, Ni, Cu, Zn, As, Cd, and Pb, were detected in CPM. The formation mechanism of CPM was analyzed in combination with flue-gas treatment. It was shown that the treatment process "activated carbon- flue-gas countercurrent-integrated purification technology + ammonia spraying" used in furnaces A and B was less effective in removing CPM, water-soluble ions, metals, and compounds than that of "selective catalytic reduction denitrification + limestone-gypsum wet desulfurization (spraying NaOH solution)" in furnaces C and D. Hence, different flue-gas treatment technologies and operation levels played vital roles in the formation, transformation, and removal of CPM from flue-gas. Organic components in CPM discharged from furnace A were determined via gas chromatography-mass spectrometry, and the top 15 organic components in CPM were obtained using the area normalization method. N-alkanes accounted for the highest proportion, followed by esters and phenols, and most of them were toxic and harmful to humans and ecosystems. Therefore, advanced CPM treatment technologies should be developed to reduce atmospheric PM and its precursors to improve ambient air quality in China.
为研究焦化厂排放烟气中的总颗粒物（TPM），基于美国环境保护局2017年推荐的方法202以及中国发布的HJ 836—2017，设计并开发了一套可用于采集可过滤颗粒物（FPM）和可凝结颗粒物（CPM）的采样系统。利用该系统，对中国4座名为A、B、C和D的焦炉排放烟气中的FPM和CPM进行了测试。此外，同时检测了CPM中存在的9种水溶性离子、20种元素和有机物，以确定其生成机制。统计数据表明，焦化烟气中FPM排放水平较低，平均质量浓度小于10 mg/m。然而，CPM和TPM排放水平较高，A、B、C和D炉的TPM质量浓度分别为130±11.1、84.4±6.36、35.1±17.0和63.8±13.0 mg/m。TPM的主要成分是CPM，A、B、C和D炉中CPM的平均质量浓度分别占TPM的98%、95%、68%和95%。水溶性离子是CPM的重要成分，A、B、C和D炉中水溶性离子的总浓度分别占CPM的70%、87%、42%和66%。在CPM中检测到了Mn、Cr、Ni、Cu、Zn、As、Cd和Pb等有毒有害重金属。结合烟气处理对CPM生成机制进行了分析。结果表明，A炉和B炉采用的“活性炭-烟气逆流-一体化净化技术+喷氨”处理工艺在去除CPM、水溶性离子、金属和化合物方面不如C炉和D炉采用的“选择性催化还原脱硝+石灰石-石膏湿法脱硫（喷NaOH溶液）”处理工艺有效。因此，不同的烟气处理技术和运行水平对烟气中CPM的生成、转化和去除起着至关重要的作用。通过气相色谱-质谱联用仪测定了A炉排放CPM中的有机成分，采用面积归一化法得到了CPM中含量排名前15的有机成分。正构烷烃占比最高，其次是酯类和酚类，其中大多数对人类和生态系统有毒有害。因此，应开发先进的CPM处理技术，以减少大气中的PM及其前驱物，改善中国的环境空气质量。
