| 引用本文: | 杜瑞岭,吴铿,巢昌耀,徐大安,张黎,张兵.热重分析法研究煤粉燃烧过程动力学的Arrhenius方程修正式[J].哈尔滨工业大学学报,2017,49(11):81.DOI:10.11918/j.issn.0367-6234.201612074 |
| DU Ruiling,WU Keng,CHAO Changyao,XU Daan,ZHANG Li,ZHANG Bing.A modified Arrhenius equation for studying the combustion kinetics of pulverized-coal by thermogravimetric analysis[J].Journal of Harbin Institute of Technology,2017,49(11):81.DOI:10.11918/j.issn.0367-6234.201612074 |
|
| 摘要: |
| 煤粉的燃烧过程常被作为能量的提供者应用于不同工业，为研究升温速率对煤粉燃烧过程动力学的影响.本文采用热重分析法对20 ℃/min、25 ℃/min、30 ℃/min和35 ℃/min升温速率下的煤粉燃烧过程进行分析.结果表明：随升温速率的提高，煤粉燃烧过程有明显的热滞后现象.根据煤粉燃烧过程的特点，以反应速率曲线波谷对应的温度点，将着火点到燃尽点的燃烧过程划分为两个阶段，并分别采用界面化学反应模型和内扩散模型来描述相应阶段的动力学过程.由所获得动力学参数可知，不同升温速率下活化能Eai和指前因子Ai的动力学补偿效应可表示为ln Ai=aEai+b，升温速率β对活化能Eai的影响可表示为Eai=△Ealn βi+Ea0.随将常用的Arrhenius方程ln ki=-Ea0/RT+ln A0修正为ln ki=-Ea0/RT+△Ea(a-1/RT)ln βi+ln A0来描述升温速率β对煤粉燃烧过程反应速率常数k的影响.而后，采用10 ℃/min、15 ℃/min、40 ℃/min和45 ℃/min升温速率下的煤粉燃烧试验对Arrhenius方程修正式的外推性进行验证，效果良好.因此，Arrhenius方程修正式不仅能很好地描述升温速率β对煤粉燃烧过程化学反应速率常数k的影响，而且还具有一定的外推性.
|
| 关键词: 煤粉燃烧 升温速率 Arrhenius方程修正式 动力学参数 非等温体系 |
| DOI：10.11918/j.issn.0367-6234.201612074 |
| 分类号:TQ530.2 |
| 文献标识码:A |
| 基金项目:国家自然科学基金(51274026) |
|
| A modified Arrhenius equation for studying the combustion kinetics of pulverized-coal by thermogravimetric analysis |
|
DU Ruiling,WU Keng,CHAO Changyao,XU Daan,ZHANG Li,ZHANG Bing
|
|
(State Key Laboratory of Advanced Metallurgy (University of Science and Technology Beijing) 100083 Beijing, China)
|
| Abstract: |
| 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.
|
| Key words: pulverized-coal combustion heating rates modified Arrhenius equation kinetic parameters non-isothermal system |
