Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, PR China.
Jiangsu Frontier Electric Power Technology Co., Ltd., Nanjing 211102, PR China.
Carbohydr Polym. 2015;127:363-71. doi: 10.1016/j.carbpol.2015.03.067. Epub 2015 Mar 30.
Xylan-based hemicellulose sample is tested in TG-MS under He, 7% O2, 20% O2 and 60% O2, in order to underpin the understanding of thermo-degradation mechanism of hemicellulose and biomass. The mass loss history recorded by TG can be divided into two main stages: (1) low-temperature stage with the peak located at around 265°C associated with thermal cracking of hemicellulose, and (2) high-temperature stage with the peak enhanced and shifted to lower temperatures by oxygen concentration ascribed to char combustion. A number of prominently evolved ions identified by MS can be designated to acetone, acetic acid, furfural, water, CO, CO2 and so on. The releasing profile of smaller fragments (water, CO and CO2) follows the pattern of DTG curve under different oxygen concentrations (especially for that in the high temperature stage). A three-step consecutive kinetic model employing "n-order reaction function" is proposed and achieved good fit for the experimental mass loss data of thermo-oxidation of hemicellulose.
以木聚糖为基础的半纤维素样品在 He、7%O2、20%O2 和 60%O2 下进行 TG-MS 测试，以深入了解半纤维素和生物质的热降解机制。TG 记录的质量损失历史可分为两个主要阶段：（1）低温阶段，峰值位于约 265°C，与半纤维素的热裂解有关，（2）高温阶段，由于氧浓度增强，峰值向较低温度移动，归因于炭的燃烧。通过 MS 鉴定出的许多明显演化的离子可指定为丙酮、乙酸、糠醛、水、CO、CO2 等。在不同氧浓度下（特别是在高温阶段），较小碎片（水、CO 和 CO2）的释放谱遵循 DTG 曲线的模式。采用“n 级反应函数”的三步连续动力学模型被提出并很好地拟合了半纤维素热氧化的实验质量损失数据。
