Experimental investigation on the effect of O2 and CO2 on burning rates during oxyfuel combustion of methane
Experimental investigation on the effect of O2 and CO2 on burning rates during oxyfuel combustion of methane
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DOI：
10.1016/j.proci.2010.05.047
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
P. Heil;D. Toporov;M. Förster;R. Kneer
中科院分区：
文献类型：
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作者：
P. Heil;D. Toporov;M. Förster;R. Kneer
对于在CO2/O2气氛中的燃烧，称为氧燃烧，必须预期改变的燃烧速率。以前的研究报告指出，这不仅可以用不同的热物理和辐射性质来解释，而且还可以用CO2直接参与化学反应的事实来解释。本文介绍了一个实验研究富氧燃料甲烷燃烧的目的是调查的重要性，高浓度CO2的化学效应。在25 kW的无焰燃烧炉中进行了实验，该无焰燃烧炉提供了在恒定的反应器温度下在CO2/O2混合物中在宽的氧浓度范围内实现甲烷稳定燃烧的可能性。这允许通过保持影响燃烧速率的其余因素恒定来关注CO2的化学效应。通过详细的炉内烟气成分和温度测量，研究了四种不同的氧化剂混合物（CO2/O2和N2/O2，O2含量分别为21vol%和18vol%）。在N2/O2气氛中燃烧的情况下，不同的O2浓度得到的CO曲线重叠，从而表明，改变O2浓度不影响燃烧速率，保持温度恒定。在CO_2/O_2气氛下燃烧时，CO浓度远高于N_2/O_2气氛下的CO浓度。与N2/O2相比，O2浓度对富氧燃烧中CO的产生和消耗速率有显著影响。在这项工作中得到的结果表明，通过消除的影响：摩尔热容，CO2解离，和热辐射，它可以估计，所观察到的影响，高浓度的CO2燃烧速率可以归因于它的参与化学反应。氧燃料中O2的增加导致这种影响的减少，然而，对确切的机制进行进一步的调查是必要的。
For combustion in an CO2/O2atmosphere, known as oxy-combustion, altered combustion rates have to be expected. Previous investigations reported that this can be explained not only with the different thermophysical and radiative properties, but also by the fact that CO2participates directly in the chemical reactions. This paper presents an experimental study on oxyfuel methane combustion with the aim to investigate the importance of the chemical effects of high CO2concentrations. Experiments have been carried out in a 25kW furnace for flameless combustion which provides the possibilities to achieve stable combustion of methane within a wide range of oxygen concentrations in the CO2/O2mixture at constant reactor temperature. This allows to focus on the chemical effects of CO2by keeping the remaining factors affecting the combustion rate constant. Four different oxidizer mixtures (CO2/O2and N2/O2both with 21vol% and 18vol% O2) have been studied by detailed in-furnace measurements for flue gas compositions and temperature. In case of combustion in N2/O2atmosphere, the CO profiles obtained for different O2concentrations overlap thus demonstrating that changing the O2concentration did not affect combustion rates, with keeping the temperature constant. In case of combustion in CO2/O2atmosphere, the CO concentrations obtained were much higher than those in N2/O2atmosphere. In contrast to N2/O2, the O2concentrations had a significant impact on the production and consumption rates of CO in oxyfuel combustion. The results obtained in this work demonstrated that by elimination of the influence of: molar heat capacity, CO2dissociation, and thermal radiation, it can be estimated that the observed effects of high CO2concentrations on combustion rates can be attributed to its participation in the chemical reactions. An increase of O2in oxyfuel led to a reduction of this impact, however, further investigations on the exact mechanism are necessary.