Structure characteristics and gasification activity of residual carbon from entrained-flow coal gasification slag
Structure characteristics and gasification activity of residual carbon from entrained-flow coal gasification slag
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DOI：
10.1016/j.fuel.2014.01.011
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发表时间：
2014-04
期刊：
影响因子：
7.4
通讯作者：
Shiyong Wu;Sheng Huang;Liyuan Ji;Youqing Wu;Jinsheng Gao
中科院分区：
文献类型：
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作者：
Shiyong Wu;Sheng Huang;Liyuan Ji;Youqing Wu;Jinsheng Gao
利用孔结构分析仪、扫描电子显微镜、拉曼光谱和热重分析仪对气流床煤气化炉渣残炭的结构特征和气化活性进行了研究。同时，以一种煤焦残炭为参照。结果表明，通常被认为是气化炉渣中“未燃尽碳”的残碳可能来源于原煤热解的挥发物(特别是具有大分子结构的挥发物)、部分气化的碳和/或未反应的热解碳。与煤焦中的残碳相比，气化渣中的残碳具有更大的孔表面积、更大的平均孔径、更有序的碳晶结构和更少的总活性中心，而粗、细渣中的残碳表现出明显更高的气化活性，这主要归因于其相当丰富的孔隙度。与细渣中的残碳相比，粗渣中的残碳具有较低的孔表面积、更多的无序碳晶体结构和更多的总活性中心，但粗渣中的残碳表现出更高的气化活性，尤其是在碳转化率为0.5左右后。这可能是由于粗渣残碳中总活性中心较多，尤其是以sp2-sp3键混合形式存在的较多活性中心所致。此外，还可以推测sp2键形式的活性中心的活性优于sp2-sp3键混合形式的活性中心。
The structure characteristics and gasification activity of residual carbon from entrained-flow coal gasification slag were mainly investigated using a pore structure analyzer, a scanning electron microscopy, a Raman spectroscopy and a thermo-gravimetric analyzer. Simultaneously, a kind of residual carbon from coal chars was used for a reference. Results showed that the residual carbon which was usually considered as “theunburnt carbon” in gasification slags, was potentially originated from volatile matters (especially those with macromolecular structures) of the original coal pyrolysis, partly-gasified carbons and/or unreacted pyrolytic carbons. Compared to the residual carbon in coal chars, that in gasification slags had a higher pore surface area, a larger average pore size, a more ordered carbon crystalline structure and less total active sites, whereas that in both coarse and fine slags presented a distinctly higher gasification activity, mainly ascribed to its quite more abundant porosity. Compared to the residual carbon in the fine slag, that in the coarse slag had a lower pore surface area, a slightly more disordered carbon crystalline structure and more total active sites, but that in the coarse slag presented a higher gasification activity, especially after the carbon conversion of around 0.5. This was probably due to more total active sites in the residual carbon of the coarse slag, especially its more active sites with mixed sp2–sp3bond form. Besides, it also could be inferred that the activity of active sites with sp2bond form was superior to that with mixed sp2–sp3bond form.