量子化学理论对煤灰熔融特性的调控机制

Regulation mechanism of coal ash fusion characteristicsfrom quantum chemistry theory

在对添加剂(助熔剂、耐熔剂)、配煤和生物质三种方法调控煤灰熔融特性综述的基础上,从量子化学理论的角度对煤灰中矿物质变化机理从微观上加以阐述。添加剂在本质上改变桥氧键(Si—O—Si)与非桥氧键(Si—O—M,M为金属离子)比例,引起了硅酸盐熔体的结构变化,从而导致灰熔融温度的变化。从莫来石和钠长石生成的角度讨论配煤对灰熔融特性的调控机制。从分子动力学模型(MD)的角度来论述生物质中CaO对煤灰的熔融特性影响。最后对煤灰熔融特性进行总结与展望,为预防煤转化过程中结渣问题提供参考。

On the basis of summarizing the three methods of controlling the melting characteristics of coal ash:additives(flux,flux resistant),coal blending and biomass,the change mechanism of minerals in coal ash is expounded from the perspective of quantum chemistry theory.The additive essentially changes the ratio of bridging oxygen bond(Si—O—Si)to non bridging oxygen bond(Si—O—M,M is metal ion),changes the structure of silicate melt,and changes the melting temperature of coal ash.The regulation mechanism of coal blending on ash melting characteristics is discussed from the perspective of the formation of mullite and albite.The effect of Cao in biomass on the melting characteristics of coal ash is discussed from the perspective of molecular dynamics model(MD).Finally,the fusion characteristics of coal ash are summarized and prospected,which provides a reference for preventing slagging in the process of coal conversion.