燃煤细颗粒物排放实验及形成机理

为了研究不同变质程度煤粉燃烧后细颗粒物排放特性及生成机理，选取4种不同变质程度的煤，在实验室滴管炉（DTF）上开展了燃煤细颗粒物排放的实验研究，阐述了煤燃烧过程颗粒物形成机理，分析了煤中外在矿物和内在矿物对细颗粒物生成的贡献。实验结果表明煤燃烧颗粒物排放呈三模态分布，峰值分别0.05，0.5和5 μm左右；煤的变质程度和温度对于颗粒物的三模态分布几乎没有影响；温度促进细模态颗粒物的生成；难熔元素，如Al和Si在粗颗粒中明显富集；易挥发元素如S在超细模态颗粒物中明显富集；燃煤粗颗粒主要由煤中内、外在矿物的熔融聚合形成，黏附在煤胞壁上的内在矿物在煤焦破碎过程中熔融聚合可能是形成中间模态中不规则形貌颗粒物的原因之一。

Formation mechanisms of fine particles generated from coal combustion

In order to investigate the emission characteristics and formation mechanisms of fine particles generated from coal combustion,four kinds of coals with different ranks were chosen.The coal combustion experiments were conducted in a lab-scale drop tube furnace.The results indicate that fine particles generated from coal combustion present as tri-modal distribution,and the three peaks located at 0.05，0.5 and 5 μm.External parameters including,coal ranks and temperatures,have no impact on the tri-modal distribution of the fine particles generated from coal combustion.However,high temperature enhances the yields of ultrafine particles.Refractory elements,such as Al and Si are enriched in coarse particles.Volatile elements,such as sulfur,are obviously enriched in ultrafine particles.Coarse particles are mainly from the melting and coalescence of the exclude and included minerals in coal.The transformation behaviors of included minerals which are adhered on the surface of cenosphere contribute greatly for the irregular shapes of fine particles of the middle mode.