煤灰熔融过程中的矿物演变及其对灰熔点的影响

Mineral Conversion of Coal-ash in Fusing Process and the Influence to ash Fusion Point

煤的结渣特性是影响电厂锅炉安全经济运行的主要因素之一。该文利用热分析方法和X-射线衍射物相分析对低灰熔点的神木煤(温家梁,TDT=1200℃)和高灰熔点的淮南煤(新庄,TDT>1500℃)煤灰在加热过程中矿物质的热行为及其演变进行了对比研究,2种煤灰的热分析曲线存在较大差异,它们的矿物质成分也随着温度升高发生了不同的转变,分别对其灰熔点产生了不同的影响。温家梁灰中大量存在的CaCO3、CaSO4为钙黄长石、钙长石的大量生成提供了条件,这2种矿物的低温共熔是温家梁煤灰熔点低的主要原因;新庄灰中大量生成的莫来石使得新庄灰的熔点很高。该文的对比研究为研究配煤解决锅炉结渣问题提供了新的思路。

Slagging characteristics of coal is one of the main factors which influence the safety and economy of boiler in power plant. The Thermal behavior of two coal-ashes is studied by TG-DSC ＆ XRD. The two coal-ashes are made from Wenjialiang （Shenmu） coal and Xinzhuang （Huainan） coal, which have different ash fusion point （TDT= 1200℃ vs. 〉1500℃ ）. There are distinct difference in TG-DSC curves and different mineral changing in heating process between the two coal-ashes, which finally cause the distinct difference of their ash fusion points. CaCO3 ＆ CaSO4 which exist largely in Wenjialiang coal-ash impel the generation of anorthite ＆ submellite in heating process, then the anorthite ＆ submellite generate eutectic mixture. It is the main factor of descending of ash fusion point of Wenjialiang coal. Contrarily, mullite that abundantly generated in Xinzhuang coal-ash makes it possible to have very high ash fusion point. The contrastive study of the two coal-ashes in this paper would provide a new way to resolve slag issue of boiler in power plant.