A modified Arrhenius equation for studying the combustion kinetics of pulverized-coal by thermogravimetric analysis

被引：0
|
作者：
Du R. [1 ]
Wu K. [1 ]
Chao C. [1 ]
Xu D. [1 ]
Zhang L. [1 ]
Zhang B. [1 ]
机构：
[1] State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing
来源：
Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology | 2017年 / 49卷 / 11期
关键词：
Heating rates; Kinetic parameters; Modified Arrhenius equation; Non-isothermal system; Pulverized-coal combustion;
D O I：
10.11918/j.issn.0367-6234.201612074
中图分类号：
学科分类号：
摘要：
The combustion process of pulverized-coal is widely used in different industries as a supplier of energy. In order to investigate the influence of heating rate on the combustion kinetics of pulverized-coal, the study of combustion pulverized-coal at different heating rates (20℃/min, 25℃/min, 30℃/min, and 35℃/min) was conducted by thermogravimetric analysis. The results show that the entire combustion process indicates a thermal hysteresis phenomenon with heating rate increasing. According to the characteristics of the pulverized-coal combustion, the combustion process from ignition temperature to burnout temperature is divided into two regions according to the temperature where the reaction rate curve reaches the valley value. Then, interfacial chemical reaction model and internal diffusion model are successfully applied to describe the two regions of combustion process. The obtained corresponding kinetic parameters show that the kinetic compensation effect between activation energy Eai and pre-exponential factor Ai for different heating rates is expressed as ln Ai=aEai+b and the influence of heating rate β on activation energy Eai can be described as Eai=△Ealn βi+Ea0. Later, the Arrhenius equation (ln ki=-Ea0/RT+ln A0) is modified as ln ki=-Ea0/RT+△Ea(a-1/RT)ln βi+ln A0 to describe the influence of heating rate β on the rate constant k of pulverized-coal combustion. Finally, the extrapolation reliability of the modified Arrhenius equation is validated by the experimental data at different heating rates(10℃/min, 15℃/min, 40℃/min, and 45℃/min). Therefore, the modified Arrhenius equation is not only the most expedient way to depict the combustion kinetic at different heating rates, but also provides extrapolation reliability over a broad range. © 2017, Editorial Board of Journal of Harbin Institute of Technology. All right reserved.
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页码：81 / 86
页数：5
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