FTIR和XRD在断层构造煤结构分析中的应用

Application of FTIR and XRD in Coal Structural Analysis of Fault Tectonic

为探究断层构造作用对煤化学结构特征和微晶结构特征的影响,采用傅里叶变换红外光谱(FTIR)和X射线衍射(XRD)分析,对红庆梁矿和段王矿的原生煤及断层构造煤进行分析。结果表明,受断层构造作用影响,红庆梁、段王断层构造煤中苯环二取代、苯环四取代的含量明显大于原生煤,苯环三取代和苯环五取代的含量低于原生煤,断层构造煤中C—O—C伸缩振动、—CH_(2)反对称弯曲振动、—CH_(3)、—CH_(2)和芳环—OH含量均多于原生煤,断层构造煤中醚C—O振动、芳烃CC、—CH和OH—π含量低于原生煤。红庆梁、段王断层构造煤的芳碳率fa是原生煤的1.01和1.03倍,芳环缩合度DOC是原生煤的1.01倍和3.7倍,CH_(2)/CH_(3)值是原生煤样的0.933倍和0.94倍,芳香度I分别是原生煤样的1.01倍和1.34倍。说明断层构造作用促使官能团和脂肪链脱落,增加煤的缩聚程度,降低煤中脂肪侧链的长度,增大芳香结构含量。XRD测试结果表明,原生煤和断层构造煤具有相近的矿物组分,断层构造作用未对煤中矿物组分的类型产生明显的改变。在2θ=26°附近存在特征(002)带,表明存在少量的层状石墨结构,然而在2θ=45°附近并没有清楚地显示(100)带,说明煤中石墨结构的基面生长水平较低。红庆梁、段王断层构造煤的晶间间距d_(002)值与原生煤相比变化很小,微晶堆积高度L_(c)值分别是原生煤的0.9045倍和0.9027倍,芳香度f_(a)-XRD值分别是原生煤的1.1439倍和1.0669倍,晶体堆叠平均层数N_(ave)值分别是原生煤的0.90945倍和0.92356倍。断层构造作用减小煤的芳香层片堆砌度,增大煤的芳香度,减少了煤微晶结构单元的堆叠层数,说明断层构造促进煤中非芳香化合物向芳香化合物的转化。断层构造煤的芳香度、成熟度更高,断层构造煤的燃烧反应性弱于原生煤。

In order to explore the influence of fault tectonism on the characteristics of the chemical structure of coal and the characteristics of the microcrystalline structure.The primary coal and fault tectonic coal of the Hongqingliang mine and Duanwang mine were analyzed by Fourier Transform Infrared Spectroscopy FTIR and X-ray diffraction XRD.The following results showed that because of the influence of fault tectonism,the contents of benzene ring disubstituted and benzene ring tetrasubstitution in Hongqingliang and Duanwang fault tectonic of coal were significantly higher than those in primary coal,the contents of benzene ring trisubstitution and benzene ring pentasubstitution were lower than those in primary coal,and the contents of ether bond C—O—C stretching vibration,methylene—CH_(2)antisymmetric bending vibration,both methyl,methylene and aromatic ring substituted by hydroxyl—CH_(3)and—CH_(2)in fault tectonic of coal were higher than those in primary coal.In comparison,the contents of the polar bond of ether vibration,carbon-carbon double bond,methine and phenol of aromatic hydrocarbon in fault tectonic of coal were lower than those in primary coal.The aromaticity faof fault tectonic of coal in Hongqingliang and Duanwang mine was 1.01 and 1.03 times that of primary coal,the aromatic cyclocondensation DOC was 1.01 and 3.7 times that of primary coal,the ratio of CH_(2)to CH_(3)was 0.933 and 0.94 times that of primary coal,and the aromaticity I was 1.01 and 1.34 times that of primary coal,respectively.The conclusions showed that fault tectonism influenced promoting the shedding of functional groups and fat chains,increasing the degree of polycondensation of coal,reducing the length of fat side chains in coal and increasing the content of aromatic structure.The XRD test results showed that the primary coal and the fault tectonic coal had similar mineral components,and the fault tectonism did not significantly change the types of mineral components in coal.There was a(002)characteristic band near the diffraction angle 2θ=26°,which indicated the presence of a small amount of layered graphite structure,while there was no displayed zone,which indicated the basal low growth level of graphite structure in coal.Compared with the primary coal,the value of the variation range of intergranular spacing d_(002)of the fault tectonic of coal in Hongqingliang and Duanwang mine was very small.The value of the microcrystalline stacking height L_(c)was 0.9045 times and 0.9027 times of the primary coal respectively,the value of the aromaticity f_(a)-XRDwas 1.1439 times and 1.0669 times of the primary coal respectively,and the value of the average layer N_(ave)of the crystal stacking was 0.90945 times and 0.92356 times of the primary coal respectively.Because of the fault tectonism,the stacking degree of aromatic lamellae of coal reduced,the aromaticity of coal increased,and the stacking layers of coal microcrystalline structural units reduced,indicating that the fault tectonism promoted the transformation from non-aromatic compounds to aromatic compounds in coal.The aromaticity and maturity of the fault tectonic coal were higher,but the combustion reactivity of fault tectonic coal was weaker than that of primary coal.