Abstract The changes in chemical structures over the plastic layer region during the coking of coals have a significant impact on coke formation and coke quality. This paper employed the Solid-state 13Carbon Nuclear Magnetic Resonance (13C NMR), and the Synchrotron attenuated total reflection Fourier transform infrared (ATR-FTIR) microspectroscopy (Synchrotron IR) to study the transformation of the chemical structures in plastic layer samples. The light gases (mainly methane and hydrogen) released from coking process were analyzed using micro gas chromatography (micro-GC) connected to a small coking reactor heated in an electric furnace that simulated the formation of the plastic layers. The results show clearly that the total aromaticity increased consistently in the plastic layers for all coals tested, while the amounts of side-chains decreased significantly during the plastic layer. There was a clear trend showing that the total number of bridge bonds and the looped structures, indicating that the degree of cross-linking would increase through the plastic layer. The plastic layer samples from low fluidity exhibited cross-linking structures with a high degree of branching and aromaticity, while those from high fluidity coals formed cross-linking structures with a relatively low degree of aromaticity and branching but with a large number of bridge bonds and looped structures. The transferable methyl, methylene and hydrogen were strongly correlated to the cross-linking reaction and side-chain elimination in the thermoplastic region, which is reflected by the release profiles of methane and hydrogen gas during the plastic layer stage.

中文翻译：

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澳大利亚煤焦化过程中塑料层化学结构变化的综合研究

摘要 煤焦化过程中塑性层区域化学结构的变化对焦炭的形成和焦炭质量有显着影响。本文采用固态 13 碳核磁共振 (13C NMR) 和同步辐射衰减全反射傅里叶变换红外 (ATR-FTIR) 显微光谱 (Synchrotron IR) 来研究塑料层样品中化学结构的转变。使用微型气相色谱仪 (micro-GC) 分析焦化过程中释放的轻质气体（主要是甲烷和氢气），该色谱仪连接到在电炉中加热的小型焦化反应器，模拟塑料层的形成。结果清楚地表明，对于所有测试的煤，塑料层中的总芳香度持续增加，而在塑料层中侧链的数量显着减少。有一个明显的趋势表明桥键和环状结构的总数，表明交联度会通过塑料层增加。低流动性的塑料层样品表现出高度支化和芳香性的交联结构，而高流动性煤层样品形成的交联结构具有较低的芳香性和支化度，但具有大量的桥键和环状结构。可转移的甲基、亚甲基和氢与热塑性区域的交联反应和侧链消除密切相关，这反映在塑料层阶段甲烷和氢气的释放曲线上。