选用高Ca、高Fe含量的神华煤,在沉降炉系统中进行空气以及O2/CO2燃烧实验。利用X射线荧光探针(XRF)、X射线衍射仪(XRD)、先进计算机控制扫描电镜(CCSEM)分别对总灰元素、晶相组成以及主要矿物元素的共生特性进行深入表征。结果表明氧/燃料燃烧促进了Fe、Ca与其他矿物元素的交互反应,总灰中Fe在Fe-rich类矿物分布减少,而在铁铝硅酸盐(Fe-alsil),尤其是在Fe与Ca发生交互反应的Fe+Ca类矿物的分布增加,同时Ca也存在类似的分布规律。对总灰中Fe+Ca类矿物深入分析发现,氧/燃料燃烧条件下总灰中Fe+Ca类矿物结渣倾向更严重(Fe2O3/Ca O摩尔比为0.5-3)。
Shenhua coal, with high concentration of Ca and Fe, was subjected to combustion in the drop tube furnace(DTF) in both air and O2/CO2 atmosphere. XRF, XRD and CCSEM were used to characterize elemental composition, mineralogy and element symbiotic properties of bulk ash. Oxy-fuel combustion promoted interaction of Fe and Ca with other minerals. However, the amount of Fe distributed in iron aluminosilicate(Fe-alsil), especially in Fe+Ca minerals increased. The same distribution tendency of Ca was observed. Further analysis found that Fe+Ca mineral in oxy-fuel combustion bulk ash had more serious slagging propensity(with Fe2O3/Ca O mole ratios 0.5—3) than that in air combustion bulk ash.