Drastic changes in biomass char structure and reactivity upon contact with steam
Drastic changes in biomass char structure and reactivity upon contact with steam
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DOI：
10.1016/j.fuel.2007.05.057
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发表时间：
2008-06
期刊：
影响因子：
7.4
通讯作者：
D. M. Keown;J. Hayashi;Chun-Zhu Li
中科院分区：
文献类型：
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作者：
D. M. Keown;J. Hayashi;Chun-Zhu Li
通过在惰性气体气氛中以缓慢的加热速率加热至700-900°C来热解澳大利亚甘蔗垃圾生物质。然后用蒸汽原位气化炭。我们的研究结果表明，在400°C下，用蒸汽气化半焦，即使只有20秒，当半焦转化率最低时，也会导致半焦与空气的固有反应性急剧降低。焦炭反应性的降低主要不是由于在水蒸气中气化过程中固有催化剂的可能挥发。相反，焦的FT-拉曼光谱表明，与水蒸气的焦的气化导致在焦结构的急剧变化，包括较小的环系统（3-5稠环）到大环系统（106稠环）的转变。研究认为，煤焦-水蒸气反应的中间产物，特别是氢，深入煤焦基质，引发了环缩合反应。
An Australian cane trash biomass was pyrolysed by heating at a slow heating rate to 700–900°C in an inert gas atmosphere. The chars were then gasified in situ with steam. Our results indicate that the gasification of char with steam, even only for 20s when the char conversion was minimal, resulted in drastic reduction in the intrinsic reactivity of char with air at 400°C. The decreases in the char reactivity were not mainly due to the possible volatilisation of inherent catalysts during gasification in steam. Instead, the FT-Raman spectroscopy of the chars showed that the gasification of char with steam resulted in drastic changes in char structure including the transformation of smaller ring systems (3–5 fused rings) to large ring systems (⩾6 fused rings). It is believed that the intermediates of char–steam reactions, especially H, penetrated deep into the char matrix to induce the ring condensation reactions.