不同变质程度煤在氧化过程中的表面官能团红外光谱定量分析

来源期刊:中南大学学报(自然科学版)2019年第11期

论文作者:谭波 徐斌 胡明明 杨现兵 陈坤亮 徐丞

文章页码:2886 - 2896

关键词:低温氧化;红外光谱;分峰拟合;官能团;结构参数

Key words:low-temperature oxidation; FTIR; peak fitting; functional group; structural parameters

摘    要:为研究煤在低温氧化过程中的官能团变化特征,首先利用同步热分析仪对不同变质程度煤样进行程序升温实验,并在特征温度点对其进行恒温氧化处理,然后借助傅里叶变换红外光谱法(FTIR)对原煤和氧化煤样进行分析,并对红外光谱曲线进行分段分峰拟合,计算各煤样低温氧化官能团峰面积变化和红外光谱结构参数。研究结果表明:在低温氧化过程中煤的羟基和脂肪烃的谱峰强度逐渐减弱,脂肪氢的峰面积占比不断降低,含氧官能团的峰面积占比不断减少,取代芳烃的峰面积则基本不变,同时氧化初期煤分子中芳香核较稳定,不易参与反应;低变质程度煤中脂肪烃多以短链存在,且支链化程度较高;随着煤变质程度加深,煤分子中脂肪氢的峰面积占比逐渐降低,芳香环的聚合程度则不断增强。

Abstract: In order to clarify the functional group change characteristics of coal in low-temperature oxidation process, temperature programmed experiment was carried out on coal samples with different metamorphic levels by synchronous thermal analyzer. The samples were oxidized at the characteristic temperature point, and then the raw coal and oxidized coal samples were analyzed by using Fourier transform infrared spectroscopy(FTIR). The curve-fitting analysis was employed to characterize the infrared spectrum, and the peak area of functional group after low temperature oxidation and FTIR structure parameters were also calculated. The results show that the peak intensity of hydroxyl and aliphatic hydrocarbons decreases gradually during the low-temperature oxidation of coal, and the peak area proportion of aliphatic hydrogen decreases continuously. The peak area proportion of oxygen-containing functional groups decreases, and the peak area of substituted aromatics remains basically unchanged. The aromatic nucleus is relatively stable and is not easy to participate in the reaction. The low-metamorphic coal has more short-chain aliphatic hydrocarbons and higher degree of branching. With the deepening of coal metamorphism, the peak area proportion of aliphatic hydrogen in coal molecules decreases gradually, and the degree of polymerization of aromatic rings increases.

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