Abstract In this study, the initial reaction of lignin pyrolysis was explored in depth with light gas emission combined with liquid bio-oil composition and physical-chemical structure of solid bio-char. The result reveals that lignin pyrolysis undergoes a complex initial reaction between 160 and 330 °C with significant mass loss (about 20%). Lignin molecular network begins to crack down with lignin monomer linkage breaking and light gas molecular (CO2 and CO) formation as temperature reaching 160 °C. Also, polymerization reaction involving forming larger molecular weight lignin pieces took place between 160 and 200 °C. After that (200–330 °C), lignin cracking reaction is the main reaction with lignin molecular accelerating to form heavy (dimers and trimers) and light units (monomers) in bio-oil and causing more mass loss. At the same temperature range, lignin soften reaction happens and results in lignin surface adhesion, microscopic surface structure changing and functional group evolution. As temperature over 330 °C, lignin initial pyrolysis stage finished and entered intense pyrolysis stage, with more oxygen contained functional group cracking and light lignin pieces formed.

中文翻译：

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木质素热解初期综合机理

摘要 本研究利用轻质气体发射、液态生物油成分和固态生物炭的理化结构，深入探讨了木质素热解的初始反应。结果表明，木质素热解在 160 到 330 °C 之间经历了复杂的初始反应，质量损失显着（约 20%）。当温度达到 160 °C 时，木质素分子网络开始分解，木质素单体键断裂并形成轻质气体分子（CO2 和 CO）。此外，涉及形成更大分子量木质素块的聚合反应发生在 160 和 200 °C 之间。在那之后（200-330°C），木质素裂解反应是主要的反应，木质素分子加速在生物油中形成重（二聚体和三聚体）和轻单元（单体）并导致更多的质量损失。在相同温度范围内，木质素发生软化反应，导致木质素表面粘附、微观表面结构变化和官能团演化。当温度超过330℃时，木质素初始热解阶段结束，进入强烈热解阶段，含氧官能团裂解较多，形成轻质木质素碎片。