O2/CO2燃烧对神华煤Ca和Fe交互反应影响

摘要

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/CaO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/CaO mole ratios 0.5—3) than that in air combustion bulk ash.