Mass Transfer Coefficients for the Combustion of a Char Particle in O2/CO2
Mass Transfer Coefficients for the Combustion of a Char Particle in O2/CO2
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DOI：
10.1021/ef900481c
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发表时间：
2009-10
期刊：
影响因子：
5.3
通讯作者：
Juan Yu;M. C. Zhang
中科院分区：
文献类型：
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作者：
Juan Yu;M. C. Zhang
与常规煤燃烧相比，富氧燃烧具有更高的O2和CO2含量。在较高温度下，由于气体组分的强烈非等摩尔反扩散，在半焦表面发生Stefan流，并对半焦燃烧产生显著影响。但在常规煤燃烧的研究中，Stefan流动往往被忽略。在忽略Stefan流的情况下，本文提出了氧化反应2C + O2 → 2CO和还原反应C + CO2 → 2CO的传质系数的两个修正因子。通过对各种极限燃烧条件的讨论可以看出，与氧化反应相比，还原反应对传质的修正是显著的。还原反应的校正可达74%，取决于两个反应的燃烧速率比和环境CO2含量。对氧化反应的校正也取决于...
As contrasted with the conventional coal combustion, there are higher O2 and CO2 contents in the oxy-fuel combustion. At higher temperature, Stefan flow, due to strong nonequimolar counter-diffusion of the gas component, occurs at the surface of char and has significant effects on the char combustion. But Stefan flow is often neglected in the study of conventional coal combustion. In this work, two correction factors to the case of neglecting the Stefan flow are presented for the mass transfer coefficients related to the oxidation reaction, 2C + O2 → 2CO, and the reduction reaction, C + CO2 → 2CO, respectively. According to the discussions for various limiting combustion conditions, it can be seen that the correction to the mass transfer of the reduction reaction is notable, comparing to that of oxidation reaction. The correction to reduction reaction can be up to 74%, depending on the combustion rate ratio of two reactions and the ambient CO2 content. The correction to oxidation reaction also depends on ...