DU Ruiling, WU Keng, CHAO Changyao, et al. A modified Arrhenius equation for studying the combustion kinetics of pulverized-coal by thermogravimetric analysis[J]. 2017, 49(11): 2017-11.
DOI:
DU Ruiling, WU Keng, CHAO Changyao, et al. A modified Arrhenius equation for studying the combustion kinetics of pulverized-coal by thermogravimetric analysis[J]. 2017, 49(11): 2017-11.DOI: 10.11918/j.issn.0367-6234.201612074.
A modified Arrhenius equation for studying the combustion kinetics of pulverized-coal by thermogravimetric analysis
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.