摘要
流化床技术在热转化生物质方面具有优势,但生物质流化床锅炉在运行中,经常遇到床料结渣问题。该文用流化床实验装置燃烧麦秸,发现床料发生了严重的团聚结渣,床层流化状态明显恶化。随着运行时间延长,床料颗粒表面富集越来越多的钾。分析表明,渣块中的融化物组成可以用K2O-CaO-SiO2三元系简化,三元系相图可解释融化出现的原因。由于生物质灰熔点低,燃烧的半焦表面变黏,黏结床料颗粒产生结渣。通过与细灰碰撞,床料颗粒表面形成一层均匀的灰层并融化,当灰层足够厚时,黏性力让床料颗粒通过有限的点黏结在一起,形成结渣。
The fluidized bed technology has advantges at thermal conversion of biomass, though agglomeration of bed particles is a main technical problem during operation of biomass fluidized bed boiler. Wheat straw was burning in a fludized bed experimental device, and severe bed aggelomeration emerged with deterioratied fludization state. As the combustion continued, bed particles caught more and more potassium. Analysis shows that the composition of melt agglomerate can be simplified by the ternary system K2O-CaO-SiO2, and the melting behavior can be explained by the phase diagram. Because of low melting point of straw ash, surfaces of burning char become sticky at high temperatures, and the char bonds with bed particles forming agglomerates. Melting ash coats homogeneously bed particles through collisions between bed particles and fine ash. When the coats are thick enough, adhesive force makes bed particles bond together on limited points.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2011年第23期14-20,共7页
Proceedings of the CSEE
关键词
生物质
麦秸
流化床
团聚结渣
实验
biomass
wheat straw
fluidized bed
bedagglomeration
experiment
