Experimental and Modeling Investigation on the Effect of Intrinsic and Extrinsic Oxygen on Biomass Tar Decomposition

The heteroatoms, such as oxygen, have great influence on tar decomposition reactivity. To investigate the effect of oxygen on biomass tar decomposition, thermal decomposition of three typical oxygenated tar compounds and toluene were conducted under inert and oxidative atmospheres in a flow tube reactor. The key roles of intrinsic oxygen of tar and extrinsic oxygen at controlled atmospheres were taken into consideration. Results show that all three tar compounds were easy to decompose at moderate temperatures accompanied by the polymerization reaction. 2-Methoxyphenol produced less naphthalene compared to anisole under an inert atmosphere. Intrinsic oxygen enhanced the reactivity of tar as well as inhibited the polymerization process. Moderate extrinsic oxygen addition could eliminate tar without sacrifice of combustible gases, such as H2 and CO. The reaction mechanism generator (RMG) method was used to build a complete detailed kinetic model to simulate biomass tar homogeneous conversion. The new detailed kinetic model could predict the conversion of model tar compounds as well as the real tar mixture.

氧等杂原子对焦油的分解反应活性具有显著影响。为探究氧对生物质焦油分解过程的影响，本研究在管式流动反应器中，于惰性与氧化性气氛下，针对三种典型含氧焦油模型化合物及甲苯开展了热解实验。实验同时考量了焦油固有氧与受控气氛中外源氧的关键作用。结果表明，三种焦油模型化合物在中等温度下均易于发生分解，且伴随聚合反应的进行。在惰性气氛下，2-甲氧基苯酚（2-Methoxyphenol）相较于苯甲醚（anisole）生成的萘更少。焦油自身的固有氧可提升其反应活性，同时抑制聚合反应过程。适量添加外源氧可在不损耗氢气（H₂）、一氧化碳（CO）等可燃气体的前提下实现焦油脱除。本研究采用反应机理生成器（RMG）方法构建了完整的详细动力学模型，用以模拟生物质焦油的均相转化过程。该全新详细动力学模型可同时准确预测焦油模型化合物与实际焦油混合物的转化行为。