Abstract The high yields of coke and tar pitch relating to volatile reactions can cause plug in the product lines during low temperature pyrolysis of low-rank coals. To study the potential transformation of volatile into coke during its migration in the pyrolysis process, six distillates and their blends from the same coal tar were heated at 400–600 °C. The composition, radicals of six distillates and coke structure were characterized by GC × GC–MS, ESR and Raman techniques, respectively. The results show that the coke yields increase with temperature during thermal reaction for all six distillates. When light oil and pitch are blended, the interaction between the two distillates compresses the transformation of volatile into coke above 500 °C. This can be ascribed to that the reactive hydrogen radicals generated from light oil may weaken the bonding between large molecules. By contrast, other distillates (phenolic oil, naphthalic oil, wash oil and anthracene oil) promote coke formation, resulting in higher coke yields than expected. It is also observed that the highest extent of interaction occurs between phenolic oil and pitch, which may be related to the high content of oxygen containing compounds in phenolic oil and the high electron density of the compounds in pitch.

中文翻译：

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对来自同一煤焦油的六种不同馏分的热反应过程中焦炭形成的洞察

摘要 低阶煤低温热解过程中，与挥发性反应相关的焦炭和焦油沥青的高产率会导致产品线堵塞。为了研究挥发分在热解过程中迁移过程中转化为焦炭的可能性，将来自同一煤焦油的六种馏分油及其混合物在 400-600 °C 下加热。六种馏出物的组成、自由基和焦炭结构分别通过 GC × GC-MS、ESR 和拉曼技术表征。结果表明，在所有六种馏出物的热反应过程中，焦炭产率随温度增加。当轻油和沥青混合时，两种馏出物之间的相互作用会在 500 °C 以上压缩挥发物向焦炭的转化。这可以归因于轻油产生的活性氢自由基可能削弱大分子之间的键合。相比之下，其他馏分油（酚油、萘油、洗油和蒽油）会促进焦炭的形成，导致焦炭收率高于预期。还观察到，酚油和沥青之间的相互作用程度最高，这可能与酚油中含氧化合物的含量高和沥青中化合物的电子密度高有关。