Particle Size Distributions of Fly Ash Arising from Vaporized Components of Coal Combustion: A Comparison of Theory and Experiment
Particle Size Distributions of Fly Ash Arising from Vaporized Components of Coal Combustion: A Comparison of Theory and Experiment
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DOI：
10.1021/acs.energyfuels.7b03126
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发表时间：
2017-11
期刊：
影响因子：
5.3
通讯作者：
Huimin Liu;Yueming Wang;J. Wendt
中科院分区：
文献类型：
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作者：
Huimin Liu;Yueming Wang;J. Wendt
利用100千瓦的下燃中试燃烧室，对两种煤在不同空气和全氧燃烧气氛下的亚微米煤灰气溶胶形成进行了研究。通过等速采样，再通过电子迁移率和光散射粒度测定，获得了颗粒尺寸分布（PSD）数据。PSD的亚微米部分在~ 0.3 μm处表现出“积累”模式，在某些情况下，在0.03 ~ 0.07 μm之间表现出额外的“成核”模式。亚微米气溶胶的时间演变预测使用截面凝固模型。与实验测量结果的比较表明，“积累”模式是由汽化富硅物质的混凝形成的，这种混凝发生和完成在非常接近母焦颗粒的地方，而不是在混合烟气中。这表明仔细描述单个粒子周围的微观混合现象的重要性。在此之前，人们一直认为富含钠的物种……
A 100-kW-rated down-fired pilot-scale combustor was used to explore sub-micrometer coal ash aerosol formation for two coals under various air and oxy-combustion atmospheres. Particle size distribution (PSD) data were obtained through isokinetic sampling and then by electron mobility and light-scattering particle sizing. The sub-micrometer portion of the PSD exhibited an “accumulation” mode at ∼0.3 μm and, in some cases, an additional “nucleation” mode between 0.03 and 0.07 μm. Predictions of the temporal evolution of the sub-micrometer aerosol were made using a sectional coagulation model. A comparison to experimental measurements suggested that the “accumulation” mode was formed by coagulation of vaporized silicon-rich species, which occurred and was completed very close to the parent char particle and not in the mixed flue gas. This showed the importance of carefully characterizing microscale mixing phenomena around individual particles. For the sodium-rich species that had heretofore been thought to nu...