SCI和EI收录∣中国化工学会会刊

›› 2016, Vol. 24 ›› Issue (12): 1750-1760.DOI: 10.1016/j.cjche.2016.05.048

• Chemical Engineering Thermodynamics • Previous Articles     Next Articles

A comprehensive fractal char combustion model

Yuting Liu1,2, Rong He1   

  1. 1 Department of Thermal Engineering, Tsinghua University, Beijing 100084, China;
    2 Institute of Materials, China Academy of Engineering Physics, Mianyang 621908, China
  • Received:2016-02-21 Revised:2016-05-30 Online:2017-01-04 Published:2016-12-28
  • Supported by:
    Supported by the National Natural Science Foundation of China (No. 51176096).

A comprehensive fractal char combustion model

Yuting Liu1,2, Rong He1   

  1. 1 Department of Thermal Engineering, Tsinghua University, Beijing 100084, China;
    2 Institute of Materials, China Academy of Engineering Physics, Mianyang 621908, China
  • 通讯作者: Yuting Liu,E-mail addresses:liuyuting10@mails.tsinghua.edu.cn;Rong He,E-mail addresses:rhe@mail.tsinghua.edu.cn
  • 基金资助:
    Supported by the National Natural Science Foundation of China (No. 51176096).

Abstract: The char combustion mechanisms were analyzed and a comprehensive fractal char combustion model was developed to give a better understanding and better predictions of the char combustion characteristics. Most of the complex factors affecting the char combustion were included, such as the coupling effects between the pore diffusion and the chemical reactions, the evolution of the char pore structures and the variation of the apparent reaction order during combustion, the CO/CO2 ratio in the combustion products and the correction for oxy-char combustion. Eleven different chars were then combusted in two drop tube furnaces with the conversions of the partly burned char samples measured by thermogravimetric analysis. The combustion processes of these chars were simulated with the predicted char conversions matching very well with the measured data which shows that this char combustion model has good accuracy. The apparent reaction order of the char combustion decreases, stabilizes and then increases during the combustion process. The combustion rates in the oxy-mode are generally slower than in the air-mode and the effect of the char-CO2 gasification reaction becomes obvious only when the temperature is relatively high and the O2 concentration is relatively low.

Key words: Combustion, Model, Experimental validation, Pore, Fractals

摘要: The char combustion mechanisms were analyzed and a comprehensive fractal char combustion model was developed to give a better understanding and better predictions of the char combustion characteristics. Most of the complex factors affecting the char combustion were included, such as the coupling effects between the pore diffusion and the chemical reactions, the evolution of the char pore structures and the variation of the apparent reaction order during combustion, the CO/CO2 ratio in the combustion products and the correction for oxy-char combustion. Eleven different chars were then combusted in two drop tube furnaces with the conversions of the partly burned char samples measured by thermogravimetric analysis. The combustion processes of these chars were simulated with the predicted char conversions matching very well with the measured data which shows that this char combustion model has good accuracy. The apparent reaction order of the char combustion decreases, stabilizes and then increases during the combustion process. The combustion rates in the oxy-mode are generally slower than in the air-mode and the effect of the char-CO2 gasification reaction becomes obvious only when the temperature is relatively high and the O2 concentration is relatively low.

关键词: Combustion, Model, Experimental validation, Pore, Fractals