Abstract The effects of heating rate on the evolution of tar obtained from heavy fraction of bio-oil (HB) were revealed by the change of elements, functional groups and chemical compounds. The results showed that slow heating rate had a negligible effect on the physicochemical properties of HB from 400 to 800 °C. By contrast, decomposition, radical recombination and polymerization reactions could occur at fast heating rate. A clear trend of increasing tar yields was monitored from 300−500 °C. However, a significant decrease was observed at high temperature (600−800 °C). Through elemental analyzer, C content in tar expanded with the temperature increasing, whereas N content remained unchanged. Nuclear magnetic resonance (NMR) spectroscopy results indicated that the carboxyl functional groups would be destroyed at high temperature. Furthermore, the concentrations of aromatics showed a trend to increase accompanied by a simultaneous decrease in phenols with the temperature rising according to gas chromatography/mass spectrometer (GC/MS) analysis.

中文翻译：

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不同升温速率下生物油重馏分焦油理化性质演变的比较研究

摘要 通过元素、官能团和化合物的变化，揭示了加热速率对生物油重馏分焦油生成的影响。结果表明，缓慢的加热速率对 HB 的理化性质从 400 到 800 °C 的影响可以忽略不计。相比之下，分解、自由基重组和聚合反应可以在快速加热速率下发生。从 300-500 °C 监测到焦油产量增加的明显趋势。然而，在高温（600-800°C）下观察到显着下降。通过元素分析仪，焦油中C含量随温度升高而增加，而N含量保持不变。核磁共振（NMR）光谱结果表明羧基官能团在高温下会被破坏。此外，