The evolution of nanopores and surface roughness in naturally matured coals in South China: An atomic force microscopy and image processing study
The evolution of nanopores and surface roughness in naturally matured coals in South China: An atomic force microscopy and image processing study
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华南自然熟化煤纳米孔和表面粗糙度的演变：原子力显微镜和图像处理研究
DOI：
10.1016/j.fuel.2018.07.102
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发表时间：
2018-12-15
期刊：
影响因子：
7.4
通讯作者：
Cao, Jian
中科院分区：
文献类型：
--
作者：
Jiao, Kun;Yao, Suping;Cao, Jian
由于与中国北部著名的大型聚煤区相比，中国南部的煤矿规模较小，因此对其煤质的研究一直没有得到充分的重视。研究了中国南部14个构造变形程度较低的自然成熟煤系煤样的纳米孔特征和表面粗糙度。利用原子力显微镜(AFM)和图像处理技术研究了自然成熟煤系列中纳米孔发育、表面粗糙度与热成熟度(镜质组反射率，R-o=0.65%-4.43%)之间的关系。结果表明，煤样的面孔率为0.78%~9.33%，平均孔径为7.9~27.9 nm。与热成熟度相关的孔隙演化经历了三个主要阶段，R-O值分别为-lt；1.3%、1.3%-3.7%和>；3.7%。在这三个阶段中，孔隙数量、面积孔隙度和平均孔隙大小遵循周期性的下降/上升趋势。表面粗糙度的算术平均值(R-a)为1.69-17.74 nm，均方根值(R-Q)为2.24-28.81 nm。热成熟度相对较低的煤样(R-o<；1.3%)的R-a和R-Q值主要受煤的显微组分和矿物组成的控制，而热成熟度相对较高的煤样(R-o>；1.3%)的R-a和R-Q值主要受纳米孔发育的控制。热成熟度是影响中国南部自然成熟煤纳米孔和表面粗糙度特征的重要因素。
The coals in South China has not been well investigated because the coal mines are small in volume compared with the well-known large-scale coal accumulations in North China, thus the nature of such coals is of significance to study. The nanopore characteristics and surface roughness of 14 coal samples that have experienced low degrees of tectonic deformation as a naturally matured coal series in South China were addressed. Atomic force microscopy (AFM) and image processing were applied in a study of relationships between nanopore development, surface roughness, and thermal maturity (indicated by vitrinite reflectance; R-o = 0.65%-4.43%) in the naturally matured coal series. The results show that areal porosities of the coal samples are 0.78%-9.33%, with mean pore sizes of 7.9-27.9 nm. There were three main stages of pore evolution related to thermal maturity, with R-o values of < 1.3%, 1.3%-3.7%, and > 3.7%. Pore number, areal porosity, and mean pore size follow a cyclical downward/upward trend across the three stages. Arithmetical mean (R-a) and root-mean-square (R-q) surface roughness values are 1.69-17.74 nm and 2.24-28.81 nm, respectively. R-a and R-q values of coal samples with relatively low thermal maturity (R-o < 1.3%) are controlled mainly by coal maceral and mineral composition, whereas values for coals with relatively high thermal maturity (R-o > 1.3%) are controlled by nanopore development. Thermal maturity is an important factor that influences the nanopore and surface roughness characteristics of naturally matured coals in South China.