基于多重扫描法对棉秆热解动力学的研究

Study on the Pyrolysis Kinetics of Cotton Stalk based on the Multi-scanning Method

本文基于多重扫描法对棉秆热解行为及机理进行了研究。结果表明,棉秆热解在30-600℃热解区间,分为四个区域,分别为失水、解聚＂玻璃化转变＂、主热解及炭化阶段,主反应区热重曲线和微分热重曲线都向高温方向移动。对主热解阶段采用Flynn-Wall-Ozawa（FWO）和Friedman-Reich-Levi（FRL）动力学模型对活化能E进行求解,在转化率10%到70%的范围内,棉杆的主热解阶段活化能十分稳定,两种方法的求解结果非常接近,而且线性拟合度很高。对实验数据进行非线性拟合,确定棉杆热解机理满足Avrami-Erofeev方程反应级数为0.4,机理函数形式为,G（α）=[-ln（1-α）]^2/3,f（α）=5/2（1-α）[-ln（1-α）]^3/5。

Cotton stalk pyrolysis behavior and mechanism were studied based on the multi-scanning method. The results showed that cotton stalk pyrolysis zone during 30 - 600 ℃ could be divided into four regions,namely,water loss,depolymerization ＂ glass transition＂,,main pyrolysis and charring stage. During the main reaction zone TG curves and differential TG curves were moving to high temperature. The activation energy E of the main stage of pyrolysis was solved by FWO and FRL method respectively. The results showed that the activation energy E was very stable in the conversion rate of 10% to 70%. The results of the two solving methods were very close and had a high degree of linear fitting. Experimental data were analyzed by the non-linear fitting,,and the mechanism of cotton stalk pyrolysis met Avrami-Erofeev equation. The reaction value of series（grade） was 0. 4. The function mechanism forms are G（α） = [-ln（1-α） ]^2/3 and f（α） =5/2（1-α） [-ln（1-α） ]^3/5 respectively.