循环流化床燃烧棉秆两种床料的特性

分别选用石英砂颗粒和高铝矾土颗粒作为循环流化床的床料,棉杆作为燃料,在0.2MW循环流化床上进行实验.实验结果表明,石英砂颗粒床料容易形成结渣,而高铝矾土颗粒床料使用情况良好.通过对长时间运行后的床料颗粒进行XRF和SEM/EDS分析,发现2种床料运行后的化学成分发生改变,随着运行时间的延长,碱金属在床料中富集度越来越高.通过对反应前后内部结构和成分进行比较,发现石英砂床料结渣主要是因为在颗粒的表面生成了低熔点的化合物,在高温条件下床料由于表面层相互粘结而产生结渣,而高铝钒土颗粒可以有效地防止低熔点化合物的生成,从而减少结渣.

Study on two kinds of bed materials during CFB combustion of cotton stalk

Silica and aluminous soil were used as bed materials when cotton stalk was burning in a circulation fluidized bed(CFB) combustion pilot plant(0.2 MW).After a long time operation,silica bed material was found sintered and aluminous soil bed material kept unchanged.The particles of both bed materials were then sampled.X-ray fluorescence(XRF),scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy(EDS) were employed to identify the bed materials in order to find the reason of difference.The result shows that alkali metals are enriched in the bed material particles linearly as the operation time extends.The low melting point compound produced on the surface of silica particles take responsibility for the agglomeration.Aluminous soil bed materials can prevent the formation of low melting point compound,therefore the agglomeration is reduced.