山西高阳焦煤碳结构研究与谱学表征

Spectral characterization of coal structure in Shanxi Gaoyangcoking coal

煤是由多种官能团、多种化学键组成的复杂有机结构大分子物质,有机质碳是煤结构的骨架,是构成煤中有机质及形成焦炭的主要元素。研究炼焦煤中的碳结构,对构建炼焦煤大分子结构模型,认知炼焦煤结构及反应性具有重要意义。分别利用Peakfit V4和XPS Peak4.1软件对13C CP/MAS-NMR、FTIR和XPS谱图进行拟合解析,对比研究不同测试方法的解析结果,探索炼焦煤中碳结构的主要特征,获取芳碳率、芳氢率、芳核平均结构尺寸等煤结构单元基本参数。山西高阳焦煤芳碳率的13C CP/MAS-NMR、FTIR和XPS分析结果基本一致,分别是0.81、0.83和0.81。FTIR分析结果表明,芳香结构主要包括苯环二取代、苯环四取代和苯环五取代,占比分别是39.63%、32.24%和28.13%。脂肪结构主要以亚甲基形式存在,含量达到77.43%,甲基、次甲基含量依次减少,脂肪烃碳链长度较短为0.11。因此,山西高阳焦煤中存在较多的烷基侧链。根据13C CP/MAS-NMR拟合结果,获知甲基碳fal*、亚甲基碳/次甲基碳falH、氧接脂碳falO、羰基碳/羧基碳faC、芳烃碳fa′、烷基取代芳碳faS、芳香桥碳faB、氧接芳碳faP分别为0.06、0.06、0.04、0.05、0.76、0.10、0.28、0.03,计算得到芳碳率fa、脂碳率fal、质子化芳碳faH、非质子化芳碳faN和芳核平均结构尺寸Xb分别为0.81、0.19、0.35、0.41和0.37。XPS和13C CP/MAS-NMR分析结果表明,山西高阳焦煤中羰基、醚氧键和酚羟基等碳氧官能团含量约占碳结构的5%。

Coal is a complex organic structure macromolecular substance composed of a variety of functional groups and a variety of chemical bonds.Organic carbon is the skeleton of coal structure,and is the main element that forms organic matter in coal and forms coke.Study the carbon structure in coking coal is of great significance for constructing the macromolecular structure model and understanding reactivity of coking coal.The fitting of 13C CP/MAS-NMR,FTIR and XPS spectra were analyzed by Peakfit V4 andXPS Peak4.1respectively.The analytical results of different test methods were compared and the main characteristics of carbon structure in gas-fertilized coal were explored.Basic parameters of coal structural units such as aromatic carbon ratio,aromatic hydrogen ratio and average structural size of aromatic nucleus were obtained.The results of 13C CP/MAS-NMR,FTIR and XPS analysis of the aromatic carbon ratio of Shanxi Gaoyang coking coal were basically the same,which were 0.81,0.78 and 0.81respectively.The results of FTIR analysis indicated that the aromatic structure mainly consisted of benzene ring disubstituted,benzene ring tetrasubstituted and benzene ring pentasubstituted,accounting for 39.63%,32.24%and 28.13%.The methylene group accounts for 77.43%of the structure of the aliphatic hydrocarbon,the methyl and methine content decreased in turn.Shorter aliphatic carbon chain length was 0.11.Therefore,Shanxi coal had more alkyl side chains.According to the 13C CP/MAS-NMR fitting results,it was known that fal*,falH,falO,faC,fa′,faS,faB,faO were 0.06,0.06,0.04,0.05,0.76,0.10,0.28,0.03 respectively.fa,fal,faH,faN,Xbwere 0.81,0.19,0.35,0.41,0.37 by calculated.XPS and 13C CP/MAS-NMR analysis showed that the carbonyl,ether and phenol groups were present in an amount of about 5%of carbon structure.