新疆高钙煤混烧对灰中含钙矿物熔融特性影响

选用一种高钙和一种高硅铝新疆煤，在沉降炉中进行不同比例的混煤和单煤燃烧实验。采用计算机控制扫描电镜（CCSEM）分别对燃烧后总灰矿物成分和粒径分布进行分析。基于CCSEM分析获取单颗粒灰成分数据，采用热力学平衡方法对灰中矿物液相比例进行计算，分析混煤燃烧对灰中含钙矿物熔融特性影响。结果表明，煤中有机结合态Ca极易与煤中其他矿物元素发生交互反应，交互反应后含钙矿物种类取决于煤中内在矿种类。混煤燃烧会促进灰中含钙硅铝酸盐向含钙复杂硅铝酸盐转化，同时促进含钙矿物的熔融。在低温条件下，混烧煤灰中熔融含钙矿物粒径分布受碱金属粒径分布影响；但是高温条件下，混烧促进熔融含钙矿物向大粒径煤灰迁移。

Effects of Xinjiang high calcium coal co-firing on melting characteristics of Ca-bearing minerals in ash

In this study, a high-calcium coal, a high-silicon-aluminum Xinjiang coal and their blends were burnt in a drop tube furnace. The computer-controlled scanning electron microscope (CCSEM) was used to analyze the total ash mineral composition and particle size distribution after combustion. Based on CCSEM analysis, the composition data of single particle ash was obtained. The thermodynamic equilibrium method was used to calculate the liquid phase ratio of minerals in the ash, and the effect of coal blending on the melting characteristics of calcium-containing minerals in the ash was analyzed. The results show that the organically bound Ca easily interacts with other minerals in the coal. The mineral species of Ca-bearing minerals in the bulk ash mainly depend on the included minerals in coal. Co-firing will promote the conversion of calcium-containing aluminosilicate in the ash to calcium-containing complex aluminosilicate, and at the same time promote the melting of calcium-containing minerals. Under low temperature conditions, the particle size distribution of molten calcium-containing minerals in co-fired coal ash is affected by the particle size distribution of the alkali metal; however, under high temperature conditions, co-firing promotes the migration of molten calcium-containing minerals to large particle size ash.