【摘要】 为深入认识准东煤的结渣特性,改善燃用准东煤的锅炉结渣问题,采用多反应控制段携带流反应器模拟真实煤粉锅炉中的空气分级燃烧情况,研究空气分级条件下过量空气系数对准东煤结渣特性的影响规律.采用XRD与SEMEDX对灰渣在高温条件下的熔融特性与微观形貌进行分析,并取灰样分析其燃尽率.实验结果表明:准东煤在炉膛温度为1 250℃时具有很好的燃尽效果,燃尽率达到99%以上.过量空气系数在0.7~1.2时对燃尽效果影响不明显.随着主燃区过量空气系数的升高,莫来石含量逐渐增大,结渣逐渐减轻;灰渣中Si、Fe、Na富集明显,Al含量较低,结渣较强;主燃区过量空气系数较低时,灰中铁的硅铝酸盐容易形成低温共熔体,导致结渣加重.为避免严重结渣应该使主燃区过量空气系数大于0.7,同时可以通过掺配含铁量较低的煤来减轻准东煤的结渣.更多还原

【Abstract】 For a better understanding of slagging characteristics of Zhundong coal and solving its slagging problem,entrained flow reactor with multiple reaction segments was used to simulate air staging combustion condition in PC boiler. The slagging characteristics of Zhundong coal in various excess air ratio conditions was investigated,the morphology and melting characteristics and its burnout rate were analyzed using SEM-EDX and XRD. The results show that the burnout rate of Zhundong coal is more than 99% at 1 250 ℃,and the influence of excess air ratio ranging from 0. 7 to 1. 0 on the char burnout is not obvious. With the excess air ratio increasing in the primary zone,the content of mullite increases,while the slagging characteristic reduces gradually. The Si,Fe,Na are enrich in slagging,while the content of Al is lower,and slagging is more serious. The aluminosilicate of iron is easy to form low temperature eutectic under lower excess air ratio,and it will cause slagging seriously. Therefore,the excess air ratio of the primary zone should be above 0. 7 to avoid slagging seriously,and combustion mixed with low iron coal will reduce slagging of Zhundong coal.更多还原