【摘要】 基于对循环流化床锅炉物料平衡内部机制的分析,认为循环流化床锅炉燃料适应性广的原因是炉膛中定态的物料浓度分布.在燃用低灰分燃料时,为了达到锅炉设计要求的物料浓度分布,需要额外添加循环物料,提出在炉膛空塔流速为5m/s、河沙密度为2650kg/m3时,河沙的粒径应小于300μm,且大于分离器分离效率为99%时对应的颗粒直径d99.对泰国Ajnomoto公司73.2t/h循环流化床锅炉进行设计,结果表明:在此粒度范围内,方形分离器可以满足物料平衡要求,飞灰含碳量在1%以下,燃烧效率大于99%,锅炉效率达到93.62%(日本标准),但河沙密度比煤灰大,对流化床料层阻力及一次风机的影响不可忽视.更多还原

【Abstract】 Based on the analysis of internal mechanism of material balance of the circulating fluidized bed(CFB)boiler,it is considered that the reason of the fuel flexibility of CFB boiler was the certain solid suspension density distribution in the furnace.In order to achieve the particle concentration distribution required by boiler design,additional circulating material is necessary when the low-ash fuel is fired.It is presented that when the air velocity in the empty furnace is 5 m/s and the density of the sand is 2 650 kg/m3,the diameter of the sand should be less than 300 μm,and larger than d_ 99,the particle diameter responding to the separating efficiency of 99%.Design was carried out on a 73.2t/h CFB boiler for Ajnomoto Co.in Thailand.Results shows that when the size of the sand is within above-mentioned range,the square separator can meet the requirement of material balance,and the carbon content in fly ash will be less than 1%,combustion efficiency will be more than 99%,as a result,boiler efficiency will reach 93.62%(according to Japanese standard).However,since the density of sand is bigger than that of coal ash,the resistance of the fluidizing bed and the effect on primary air fan can’t be ignored.更多还原