Abstract The oxidative pyrolysis of mallee wood, cellulose and lignin was performed and the bio-oil products were analysed to understand how the externally added oxygen react with the pyrolysis products. Both wood cylinders of diameter 8 mm and fine particles (90–300 μm) were pyrolysed in this study to understand the combined effects of biomass particle size and the presence of oxygen. The results revealed that, at a low oxygen concentration, the gas-phase oxidation of volatiles would improve the yields of levoglucosan and syringaldehyde, as well as unsaturated hydroxyl ketones/aldehydes for small wood particles through the oxygen-induced radical reactions. Although oxygen could facilitate the production of some compounds in bio-oil through the gas-phase reactions, it did lead to decreases in the heavy bio-oil yield due to the over-oxidation of some pyrolysis products (e. g. aromatics, lactones, unconjugated alkyl aldehydes/esters and carboxylic acids). The effects of oxygen on the pyrolysis of wood cylinders were more complicated than mallee wood particles due to the secondary reactions of volatiles and the reactions involving the pyrolysing particle surface. The interactions between the polysaccharide-derived and lignin-derived products in gas phase might affect the oxidation of volatiles, changing the formation of pyrolytic products (e.g. levoglucosan and syringaldehyde).

中文翻译：

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槌木生物质、纤维素和木质素的氧化热解

摘要 进行了槌木、纤维素和木质素的氧化热解，并对生物油产品进行了分析，以了解外部添加的氧气如何与热解产物发生反应。在这项研究中，直径为 8 毫米的木圆柱和细颗粒（90-300 微米）都被热解，以了解生物质颗粒大小和氧气存在的综合影响。结果表明，在低氧浓度下，挥发物的气相氧化将通过氧诱导的自由基反应提高左旋葡聚糖和丁香醛以及小木颗粒的不饱和羟基酮/醛的产率。尽管氧气可以通过气相反应促进生物油中某些化合物的产生，由于某些热解产物（例如芳烃、内酯、非共轭烷基醛/酯和羧酸）的过度氧化，它确实导致重质生物油产量下降。由于挥发物的二次反应和涉及热解颗粒表面的反应，氧气对木圆柱热解的影响比马利木颗粒更复杂。气相中多糖衍生产物和木质素衍生产物之间的相互作用可能影响挥发物的氧化，改变热解产物（例如左旋葡聚糖和丁香醛）的形成。由于挥发物的二次反应和涉及热解颗粒表面的反应，氧气对木圆柱热解的影响比马利木颗粒更复杂。气相中多糖衍生产物和木质素衍生产物之间的相互作用可能影响挥发物的氧化，改变热解产物（例如左旋葡聚糖和丁香醛）的形成。由于挥发物的二次反应和涉及热解颗粒表面的反应，氧气对木圆柱热解的影响比马利木颗粒更复杂。气相中多糖衍生产物和木质素衍生产物之间的相互作用可能影响挥发物的氧化，改变热解产物（例如左旋葡聚糖和丁香醛）的形成。