预处理稻壳及其与杨树锯末掺混燃烧特性和燃烧动力学分析

Combustion Characteristics and Kinetics Analysis of Rice Husk with Different Pretreatment and Mixing with Poplar Sawdust

采用热重技术对稻壳(DK)和杨树锯末(JM)燃烧进行分析,考察了不同预处理方式对稻壳燃烧特性的影响,并研究了不同升温速率及稻壳和杨树锯末掺混质量比对掺混燃烧特性及燃烧动力学的影响。结果表明:水洗及酸洗可使稻壳燃烧TG-DTG热重曲线向高温区移动,最大失重速率及对应失重温度升高。水洗使稻壳综合燃烧特性指数提高2.5×10-7~5.9×10-7%/(min 2·℃3),而酸洗使稻壳综合燃烧特性指数下降11×10-7~11.9×10-7%/(min 2·℃3)。不同预处理后稻壳在挥发分析出燃烧阶段的活化能高于未处理稻壳,酸洗后稻壳焦炭燃烧阶段活化能降低16.94 kJ/mol,而水洗使稻壳焦炭燃烧阶段活化能升高。提高稻壳添加比例,混合燃料着火温度和燃尽温度降低。随着升温速率的提高,混合样品综合燃烧特性指数和残余率升高。70%稻壳和30%杨树锯末混合燃料在升温速率40℃/min下燃烧产生协同效应。

The thermogravimetric technique was used to analyze the combustion of rice husk(DK)and poplar sawdust(JM).The combustion characteristics and kinetic parameters of different pretreatment methods,heating rates,and the mixing ratio of rice husk and poplar sawdust were investigated.The results showed that water and acid washing could make TG and DTG curves of rice husk combustion shift to higher temperature section,and the maximum weight loss rate and its corresponding temperature increased.Water washing increased the comprehensive combustion index by 2.5×10-7-5.9×10-7%/(min 2·℃3)of rice husk,while acid washing decreased it by 11×10-7-11.9×10-7%/(min 2·℃3).After different pretreatment,the activation energy of volatile component precipitation and combustion phase was higher than that of the original sample.Compared with the activation energy of the original rice husk in fixed carbon combustion stage,it that of acid washing rice husk reduced 16.94 kJ/mol and that of water washing sample increased.Increasing the proportion of rice husk,the ignition and burnout temperature of the blend fuel decreased.With the increase of heating rate,the integrated combustion characteristic index and residual rate of the mixed fuel improved.The 70%rice husk and the 30%poplar sawdust blended fuel produced a synergistic effect at a heating rate of 40℃/min.