The current study focused on alkaline-earth metal migration induced ash transformation and carbon structure evolution for single coal particle high-temperature gasification, with visualization experiments and surface analysis techniques. The alkaline earth metals were found to aggregate to the peripheral reaction surface, while the rest remained in the initial scattered distribution. A migration index was defined and reached an extreme value in the middle reaction stage and increased with temperature, especially for the Ca element and followed by Mg. Raman spectra show the aggregation of Ca on the particle surface disrupted the carbon structure, leading to an increase in the disordered carbon content and improving the char reactivity. The aggregation behavior led to mineral transformation and melting to a liquid slag layer on the particle surface as a eutectic. Finally, a mechanism of the aggregation behavior of ionic Ca on a single particle scale was proposed in this study.

中文翻译：

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单煤颗粒高温气化碱土金属迁移诱导灰分转化与碳结构演化的机理及相互作用


目前的研究重点是通过可视化实验和表面分析技术，研究单煤颗粒高温气化时碱土金属迁移引起的灰分转化和碳结构演化。发现碱土金属聚集到外围反应表面，而其余的仍保持最初的分散分布。定义了迁移指数，并在反应中期达到极值，并随着温度的升高而增加，尤其是Ca元素，其次是Mg​​元素。拉曼光谱显示，Ca 在颗粒表面的聚集破坏了碳结构，导致无序碳含量增加并提高了炭反应性。聚集行为导致矿物转变并熔化成颗粒表面上的液态渣层作为共晶。最后，本研究提出了单颗粒尺度上钙离子聚集行为的机制。