精制煤沥青(QI＜0.2%)是制备煤系针状焦的原料, 其热转化性质决定着所生产的煤系针状焦的质量。 利用FTIR光谱及分峰拟合的方法考察了精制煤沥青在不同热转化温度下的结构变化。 主要研究了芳香性指数(Iar)、 支链化指数(CH3/CH2)、 各基础官能团(CO, C—O, 芳环CC)含量、 芳环取代种类的变化情况。 结果表明: 精制煤沥青的Iar指数随着热转化温度的提高, 逐渐变大, 并且CH3/CH2指数逐渐增大, 说明精制煤沥青热转化过程中支链的断裂形成活性位点是诱导芳香环增大的原因之一; 随着热转化温度的升高, CO含量由最初的26.25%降低为15.62%, 芳环CC含量由43.39%增加为51.28%, 而C—O含量变化很少, 说明CO是诱导大分子芳环缩合反应的重要因素; 精制煤沥青中芳环1H和3H含量随着温度升高逐渐减小, 而4H含量逐渐升高, 说明芳环取代逐渐减小, 芳香性逐渐增加, 与Iar分析结果相吻合。

Refined coal tar pitch (QI＜0.2%) was used as the raw materials to produce coal-based needle coke. The quality of coal-based needle coke was decided by the thermal conversion properties of refined coal tar pitch. In this study, FTIR spectrum combined with curve-fitted method were used to quantitative analysis the structure changes of refined coal tar pitch in different thermal conversion temperature. The aromaticity index (Iar), branched index (CH3/CH2), contents of each basic function-groups (CO, CC, and C—O), and the species of aromatic substitution have been studied. The results showed that: The Iar and CH3/CH2 index of refined coal tar pitch increased with the increase of thermal conversion temperature. It meant that the rupture of the Branched chain may cause the production of active site, and the active site was one of the reasons to induce the aromatic rings increase. With the increase of thermal conversion temperature, the contents of CO decreased from 26.25% to 15.62%, the contents of CC improved from 43.39% to 51.28%, and the contents of C—O remained essentially unchanged. It means that, CO groups were another important reason to induce the occurrence of the condensation reaction of large molecule aromatic ring. The contents of 1H and 3H were decreased, but the content of 4H was increased, which indicated that, the aromatic substitution was also decreased, and the aromaticity improved. This phenomenon was match up to the Iar analysis.