College of Safety Science and Engineering, Liaoning Technical University, Fuxin 123000, China.
Key Laboratory of Mine Power Disaster and Prevention of Ministry of Education, Liaoning Technical University, Huludao 125105, China.
Molecules. 2023 Feb 28;28(5):2264. doi: 10.3390/molecules28052264.
In order to quantitatively study the difference in occurrence content of functional groups in coals with different metamorphic degrees, the samples of long flame coal, coking coal, and anthracite of three different coal ranks were characterized by FTIR and the relative content of various functional groups in different coal ranks was obtained. The semi-quantitative structural parameters were calculated, and the evolution law of the chemical structure of the coal body was given. The results show that with the increase in the metamorphic degree, the substitution degree of hydrogen atoms on the benzene ring in the aromatic group increases with the increase in the vitrinite reflectance. With the increase in coal rank, the content of phenolic hydroxyl, carboxyl, carbonyl, and other active oxygen-containing groups gradually decreased, and the content of ether bonds gradually increased. Methyl content increased rapidly first and then increased slowly, methylene content increased slowly first and then decreased rapidly, and methylene content decreased first and then increased. With the increase in vitrinite reflectance, the OH-π hydrogen bond gradually increases, the content of hydroxyl self-association hydrogen bond first increases and then decreases, the oxygen-hydrogen bond of hydroxyl ether gradually increases, and the ring hydrogen bond first significantly decreases and then slowly increases. The content of the OH-N hydrogen bond is in direct proportion to the content of nitrogen in coal molecules. It can be seen from the semi-quantitative structural parameters that with the increase in coal rank, the aromatic carbon ratio , aromatic degree and condensation degree increase gradually. With the increase in coal rank, (CH)/(CH) first decreases and then increases, hydrocarbon generation potential '' first increases and then decreases, maturity '' first decreases rapidly and then decreases slowly, and factor gradually decreases. This paper is valuable for analyzing the occurrence form of functional groups in different coal ranks and clarifying the evolution process of structure in China.
为了定量研究不同变质程度煤中官能团赋存含量的差异，采用 FTIR 对长焰煤、焦煤和无烟煤三种不同煤级的样品进行了表征，得到了不同煤级中各种官能团的相对含量。计算了半定量结构参数，给出了煤体化学结构的演化规律。结果表明，随着变质程度的增加，芳香基中苯环上氢原子的取代度随镜质体反射率的增加而增加。随着煤级的增加，酚羟基、羧基、羰基等活性含氧基团的含量逐渐减少，醚键含量逐渐增加。甲基含量先快速增加后缓慢增加，亚甲基含量先缓慢增加后快速减少，次甲基含量先减少后增加。随着镜质体反射率的增加，OH-π氢键逐渐增加，羟基自缔合氢键的含量先增加后减少，羟基醚的氧氢键逐渐增加，环氢键先显著减少后缓慢增加。OH-N 氢键的含量与煤分子中氮的含量成正比。从半定量结构参数可以看出，随着煤级的增加，芳香碳比、芳香度和缩合度逐渐增加。随着煤级的增加，(CH)/(CH)先减少后增加，生烃潜力“先增加后减少，成熟度“先快速减少后缓慢减少，因子逐渐减少。本文对于分析不同煤级中官能团的赋存形式，阐明我国结构的演化过程具有重要价值。
