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Chemistry and Industry of Forest Products ›› 2018, Vol. 38 ›› Issue (1): 93-100.doi: 10.3969/j.issn.0253-2417.2018.01.014

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Pyrolysis Characteristics and Kinetics of Chinese Silvergrass and Corn Stalk Based on Iso-conversional Methods

YAO Can1, TIAN Hong1, QIN Jingping2, LIU Zhengwei1, HU Zhangmao1   

  1. 1. School of Energy & Power Engineering, Changsha University of Science & Technology, Changsha 410114, China;
    2. College of Bioscience and Technology, Hunan Agricultural University, Changsha 410128, China
  • Received:2017-05-19 Online:2018-02-25 Published:2018-02-28

Abstract: The pyrolysis characteristics of Chinese silvergrass and corn stalk at different heating rates (5,10,20 and 40℃/min) were studied by thermogravimetric analysis.Pyrolysis kinetics were studied using Kissinger-Akahira-Sunose (KAS),Starink and Ozawa integration method.The TG and DTG curves demonstrated that the pyrolysis process of Chinese silvergrass and corn stalk could be divided into 4 stages:dehydration stage,transition stage,main pyrolysis stage and carbonization stage.Along with the increase of heating rate,the pyrolysis curves moved to the high temperature side,and the rate of weight loss increased,which indicated that the increase of heating rate could promote the pyrolysis reaction.The results of pyrolysis of Chinese silvergrass showed that the correlation coefficients of the three methods were more than 0.9,and the values of activation energy calculated by KAS and Starink methods were very close to each other,but the activation energy calculated by Ozawa method was lower.The activation energy of corn stalk pyrolysis obtained by Ozawa method was the highest,followed by that of Starink method and KAS method.The activation energies of Chinese silvergrass pyrolysis obtained by three methods fluctuated obviously with the increase of conversion rate in the whole pyrolysis process,which showed that a series of complex chemical reactions occurred in the pyrolysis process.When the conversion rates were 0.1-0.4,the activation energy of corn stalk pyrolysis increased sharply;but when the conversion rates were 0.4-0.8,the activation energy of corn stalk pyrolysis decreased slowly until it reached a plateau.The conversion rates of 0.1-0.3,0.3-0.7 and 0.7-0.8 corresponded to the main pyrolysis stage of hemicellulose,the main pyrolysis of cellulose,and the main pyrolysis stage of lignin,which indicated that the pyrolysis difficulty degree of the three components in Chinese silvergrass was the order of lignin > cellulose > hemicellulose.

Key words: biomass, pyrolysis kinetics, iso-conversional method, pyrolysis characteristics

CLC Number: