摘要
通过非恒温热重技术研究了铁矿石烧结用焦炭在5种不同气氛(贫氧及空气)下的燃烧动力学,采用FWO积分方法和Vyazovkin积分方法对其进行了动力学分析,并比较了在不同气氛情况下焦炭的动力学特性。结果表明,随着O_2浓度的增加和CO_2浓度的降低,焦炭的着火温度、燃尽温度降低,最大失重速率增加,综合燃烧特性指数提高,活化能增加。同时,通过两种动力学分析方法计算,随着反应深度的进行,燃烧活化能逐渐减小。通过FWO方法计算得出的焦炭燃烧活化能比Vyazovkin方法计算得出的焦炭燃烧活化能数值偏大,但其规律呈现一致性,主要原因是两种方法都是采用积分近似方式求解温度积分,由于两种方法采用的温度积分式原理不同,故其数值是会出现一定偏差,这是合理的。从经济以及节能等其他方面考虑,认为烟气循环烧结气氛中氧气浓度在18%~21%比较适合。
Combustion characteristics and kinetics of coke under five different atmosphere were investigated with non-isothermal thermogravimetric analyzer. FWO and Vyazovkin integration methods were used to analysis and compare the combustion kinetics. It is shown in the result that the ignition temperature and burnout temperature become lower,the maximum weight loss turn bigger,and combustion characteristic index are enhanced as the concentration of oxygen increases and the concentration of CO2 decreases. Calculated by the two integration methods,the activation energy decreases with the increasing burnout extent. As it may be seen,the FWO method gave higher E values than the Vyazovkin method but both gave the same order of differences between different combustion atmospheres. Because of the different Integral formula,it is fair to have different values between the two methods. The oxygen concentration between 18%-21% will be better for sintering from the sides of economic and energy.
出处
《化工进展》
EI
CAS
CSCD
北大核心
2017年第2期487-493,共7页
Chemical Industry and Engineering Progress
关键词
热重
燃烧动力学
焦炭
FWO法
Vyazovkin法
thermogravimetry analysis
combustion kinetics
coke
FWO integration method
Vyazovkin integration method
