烟秆流化床燃烧结渣特性实验

Experiment on Agglomeration Characteristics during Fluidized Bed Combustion of Tobacco Stem

在中试流化床实验台架上,以石英砂、煤灰作为床料,对烟秆在800～900℃下的燃烧聚团现象进行了研究,并对其机理进行讨论。结果表明,烟秆在流化床中与以上2种床料发生粘结的难易程度不相同,石英砂燃烧粘结现象非常严重并最终导致失流,而煤灰床料经过长时间运行没有结渣。对实验后的床料颗粒和结团分别进行XRF以及SEM/EDX分析,分析表明煤灰中的Al、Fe等元素能够与烟秆灰中的碱金属元素发生反应形成高熔点物质,阻止床料颗粒的增大,从而抑制结渣。

The agglomeration phenomenon of tobacco stems was investigated on a pilot-scale fluidized bed at temperature between 800℃ and 900℃ with two kinds of bed materials silica sand and cinder, followed by a discussion on the agglomeration mechanism. The results indicated that the inclination of agglomeration for the two bed materials above was different. Severe incineration was found in silica sand which led to defluidization finally, while no agglomeration was discovered during long-term run. The data from X-ray fluorescence and scanning electron microscopy （SEM） and energy-dispersive X-ray （EDX） indicated that A1, Fe contained in cinder could react with alkali metals in the tobacco stem ash to form high-melting compounds, which prevented the agglomerates to grow, therefore inhibit the agglomeration.