二次风改造和调整对燃用福建无烟煤循环流化床锅炉运行经济性的影响

先后对燃用福建无烟煤的DG75/3.82 11型循环流化床锅炉二次风机进行变频调速改造、量体定做高效节能型风机,并减小了二次风喷嘴截面面积,增强了二次风的穿透能力,改善了二次风的均匀混合效果,2台锅炉年平均飞灰含碳量下降了3.26个百分点。同时,二次风调整测试发现,在一次风量保持基本不变的条件下,随着二次风率的增加,飞灰含碳量开始明显减少;当二次风率在0.42左右时飞灰含碳量最低,然后飞灰含碳量随着二次风率的增加而增加。在过量空气系数λ不变的情况下,飞灰含碳量随着上、下二次风增加而减少,减少幅度逐渐收窄;当上、下二次风比超过1.3后,飞灰含碳量有所增加。在二次风率不变的情况下,灰渣比随着上、下二次风增加而减少,减少幅度逐渐收窄。

The Influence on the Operation Economic of CFB Boiler Burning Fujian-anthracite Based on the Transformation and Adjustment of Secondary Air

In order to enhance the penetration of secondary air and improve the uniformity of mixing effect of secondary air,the secondary fan of CFB boiler whose fuel was Fujian-anthracite was be transformed by conversing the frequency and conversing the rate of fan before the amount of tailor-made high-performance energy-saving fans.According to these measures,the fly-ash annual carbon content of the two DG75/3.82-11 CFB boilers had dropped 3.26 percentage points.At the same time,form the testing of adjusting the secondary air,it was found:(1)When the first air volume was hold constant,with the increasing of the rate of secondary-air,the carbon content in fly ash would decrease at first;there was a minimum value of the fly-ash carbon when the secondary air rate of about 0.42;then the fly-ash carbon contented would increased with the increasing of secondary air rate.(2) Maintenance constant of the excess air coefficient,at first the carbon content of fly ash would reduce a slight,and then slowly increased after the upper and lower secondary air ratio over 1.3.(3) When the rate of secondary-air was hold constant,the ratio of ash/slag would reduce with the growing of the upper & lower secondary air ratio,but the reducer is smeller and smeller.