Kinetics and reaction chemistry of pyrolysis and combustion of tobacco waste
Kinetics and reaction chemistry of pyrolysis and combustion of tobacco waste
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DOI：
10.1016/j.fuel.2015.04.016
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发表时间：
2015-09
期刊：
影响因子：
7.4
通讯作者：
Weixuan Wu;Y. Mei;Le Zhang;Ronghou Liu;J. Cai
中科院分区：
文献类型：
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作者：
Weixuan Wu;Y. Mei;Le Zhang;Ronghou Liu;J. Cai
在这项工作中，研究了烟草废物热解和燃烧的动力学和反应化学。对以烟叶为主的烟草废弃物样品在氮气和空气气氛下进行了理化分析和热重分析。理化分析结果表明，烟草废物样品比其他类型的木质纤维素生物质含有更多的灰分和氮。对实验TGA曲线进行数值微分得到的DTG曲线波动较大，需要进行平滑处理以进行后续的动力学分析。人们发现 Savitzky-Golay 平滑算法对于平滑烟草废物热解和燃烧的 DTG 曲线是有效的。烟草废弃物的热解过程可分为四个阶段：（a）第一阶段脂肪族羟基和强键合水合化合物裂解产生的水分蒸发，以及烟草废弃物中简单糖类和其他低温分解成分的降解； (b)第二阶段半纤维素和果胶分解，形成尼古丁； (c)第三阶段纤维素的分解； (d)最后阶段木质素的分解和炭的形成。烟草废弃物的燃烧过程可分为三个阶段：（a）与热解过程的第一阶段相同； (b) 烟草废物成分的氧化热解； (c)氧化热解炭的燃烧。采用弗里德曼微分法和迭代线性积分等变换法来估计烟草废料热解和燃烧的有效活化能。结果表明，烟草废料热解和燃烧的有效活化能随转化程度的不同而变化很大。获得的烟草废物热解和燃烧的有效活化能分别在144–338 kJ mol−1 和118–257 kJ mol−1 范围内。还得到了烟草废料成分的有效活化能、温度范围、转化程度、反应之间的关系。
In this work, the kinetics and reaction chemistry of the pyrolysis and combustion of tobacco waste were investigated. The physicochemical analysis and thermogravimetric analysis under N2and air atmospheres of the tobacco waste sample mainly consisting of tobacco leaves were performed. The physicochemical analysis results showed that the tobacco waste sample contains more ash and N than other types of lignocellulosic biomass. The DTG curves obtained from the numerical differentiation of the experimental TGA curves have many fluctuations and need to be smoothed for subsequent kinetic analysis. The Savitzky–Golay smoothing algorithm was found to be effective for the smoothing the DTG curves of the pyrolysis and combustion of tobacco waste. The pyrolysis process of tobacco waste can be divided into four stages: (a) the water evaporation generated by the cleavage of aliphatic hydroxyl groups and strongly bonded hydrated compounds, and the degradation of simpler saccharides and other low temperature decomposing components of tobacco waste in the first stage; (b) the decomposition of hemicellulose and pectin, and the formation of nicotine in the second stage; (c) the decomposition of cellulose in the third stage; and (d) the decomposition of lignin and char formation in the final stage. The combustion process of tobacco waste can be divided into three stages: (a) the same as the first stage of the pyrolysis process; (b) the oxidative pyrolysis of tobacco waste components; (c) the combustion of the oxidative pyrolysis char. The Friedman differential and iterative linear integral isoconversional methods were used for the estimation of the effective activation energies of the pyrolysis and combustion of tobacco waste. The results showed that the effective activation energies of the pyrolysis and combustion of tobacco waste varied strongly with the extent of conversion. The obtained effective activation energies are in the ranges of 144–338 kJ mol−1and 118–257 kJ mol−1for the pyrolysis and combustion of tobacco waste, respectively. The relationship among the effective activation energies, temperature range, degree of conversion, reactions of tobacco waste components was also obtained.