Air and oxy-fuel combustion characteristics of biomass/lignite blends in TGA-FTIR
Air and oxy-fuel combustion characteristics of biomass/lignite blends in TGA-FTIR
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DOI：
10.1016/j.fuproc.2011.01.005
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发表时间：
2011-05
期刊：
影响因子：
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通讯作者：
N. S. Yuzbasi;N. Selçuk
中科院分区：
文献类型：
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作者：
N. S. Yuzbasi;N. Selçuk
褐煤、橄榄渣及其50/50 wt.%的热解和燃烧特性采用热重分析仪（TGA）和傅里叶变换红外光谱仪（FTIR）对空气和富氧条件下的共混物进行了研究。热解试验分别在空气和富氧燃料环境的主要稀释气体氮气和二氧化碳环境中进行。母体燃料和混合物的热解结果表明，在这两种环境中，直至700°C的温度，重量损失曲线几乎相同，表明CO2在该温度范围内表现为惰性气体。然而，进一步的重量损失发生在CO2气氛中，在较高的温度下，由于CO2-焦炭气化反应，这导致显着增加CO和COS的形成，如在FTIR演变曲线中观察到的。混合物样品的实验和理论热解曲线之间的比较表明，在两种气氛中没有协同作用。燃烧实验在四种不同的气氛中进行：空气，富氧空气环境（30%O2 - 70%N2），氧燃料环境（21%O2 - 79%CO2）和富氧氧燃料环境（30%O2 - 70%CO2）。用CO2代替燃烧环境中的N2会导致所有样品燃烧的轻微延迟（较低的最大失重率和较高的燃尽温度）。然而，这种效果被发现是更显着的橄榄渣比褐煤。氧气水平升高使燃烧曲线向较低温度转变，并增加重量损失率。橄榄渣/褐煤混合物的燃烧曲线介于单独燃料的燃烧曲线之间。实验和理论的燃烧曲线和混合样品的特征温度之间的比较表明，在橄榄渣和褐煤的共燃过程中的母燃料之间的协同作用。
Pyrolysis and combustion behavior of indigenous lignite, olive residue and their 50/50wt.% blend in air and oxy-fuel conditions were investigated by using thermogravimetric analyser (TGA) combined with Fourier-transform infrared (FTIR) spectrometer. Pyrolysis tests were carried out in nitrogen and carbon dioxide environments which are the main diluting gasses of air and oxy-fuel environment, respectively. Pyrolysis results of the parent fuels and the blend show that weight loss profiles are almost the same up to a temperature of 700°C in these two environments, indicating that CO2behaves as an inert gas in this temperature range. However, further weight loss takes place in CO2atmosphere at higher temperatures due to CO2–char gasification reaction which leads to significant increase in CO and COS formation as observed in FTIR evolution profiles. Comparison between experimental and theoretical pyrolysis profiles of the blend samples reveals that there is no synergy in both atmospheres. Combustion experiments were carried out in four different atmospheres; air, oxygen-enriched air environment (30% O2–70% N2), oxy-fuel environment (21% O2–79% CO2) and oxygen-enriched oxy-fuel environment (30% O2–70% CO2). Replacing N2in the combustion environment by CO2causes slight delay (lower maximum rate of weight loss and higher burnout temperature) in the combustion of all samples. However, this effect is found to be more significant for olive residue than lignite. Elevated oxygen levels shift combustion profiles to lower temperatures and increase the rate of weight loss. Combustion profiles of olive residue/lignite blends lie between those of individual fuels. Comparison between experimental and theoretical combustion profiles and characteristic temperatures of the blend samples indicates synergistic interactions between the parent fuels during co-combustion of olive residue and lignite.