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采用热重分析仪,在空气气氛下对稻壳的燃烧热失重状况进行了研究,并分析了四种升温速率(5,10,20,50℃/min)对燃烧特性指数的影响。利用Coats-Redfern模型,Freeman-Caroll模型和Flynn-Wall-Ozawa模型分别计算了稻壳燃烧的活化能及频率因子。实验表明:随着升温速率的升高,燃烧性能得到良好改善,但反应起始温度和终止温度由于受热滞后性影响,向高温区偏移使着火温度升高。模型计算结果表明:稻壳燃烧的表观活化能较低,升温速率对活化能的影响并不明显,Coats-Redfern模型、Freeman-Caroll模型可用于估算,Flynn-Wall-Ozawa模型可作为重要数据参考。
The thermogravimetric analyzer was used to study the heat and weight loss of rice hulls under air atmosphere. The effects of four heating rates (5, 10, 20 and 50 ℃ / min) on the combustion characteristics were also analyzed. The activation energy and frequency factor of rice hulls were calculated by Coats-Redfern model, Freeman-Caroll model and Flynn-Wall-Ozawa model respectively. The experimental results show that the combustion performance is improved with the increase of the heating rate, but the reaction start temperature and the end temperature are affected by the thermal hysteresis, and the shift to the high temperature region causes the ignition temperature to increase. The results of model calculation show that the apparent activation energy of rice husk combustion is low, and the heating rate has no obvious effect on the activation energy. The Coats-Redfern model and Freeman-Caroll model can be used for estimation. Flynn-Wall-Ozawa model can be used as important data reference.