煤燃烧过程中矿物质气化与亚微米颗粒物形成的研究

Experimental Study on Vaporization of Minerals and Formation of Sub-micron Sized Particulates During Combustion of Coal

应用热重分析仪研究了煤中矿物质的气化,同时通过沉降炉试验台架研究了燃煤过程中亚微米颗粒的形成和排放特性,并对亚微米颗粒的形成机理进行了探讨。结果表明:矿物质的气化量随着温度的升高而增大;在1400℃时,各个元素的气化能力由大到小依次为S、Cu、Pb、Zn、Na、K、Ca、Fe、Mg、Cr和Mn;温度越高,煤粉粒径越小,氧气含量越高,形成的PM1.0的浓度越大,并富集了易气化元素S、P和Na等,PM1.0可能是由气化-凝结机理形成的。

The vaporization behavior of minerals contained in coal has been investigated with a thermogravimeter; simultaneously the formation and emission of particulars of particles of submicron size during combustion of coal was investigated with a drop-tube furnace test rig and the mechanism of submicron particle formation explored. Results show that the amount of vaporized minerals increase with rising temperature, but different elements have different vaporization potentialities, sequenced in dropping order at 1450℃ S, Cu, Pb, Zn, Na, K, Ca, Fe, Mg, Cr and Mn. The higher the temperature the smaller the coal pulverized particles; the larger the oxygen content the higher the concentration of emerging PM1.0. Particulates of submicron sizeget enriched in easily vaporizing elements like S, P and Na, and the contribution of hard to melt oxides to PM1.0 increases with increasing oxygen concentration. The corresponding PM1.0 concentration increase with increasing amounts of vaporized minerals. Simultaneously, the content of the elements Al and Si, which have a low volatility, in PM, o falls significantly short of their corresponding content in the entire ash, which indicates that PM1.0 may be formed via a vaporization-condensation mechanism. Figs 8, tables 2 and refs 12.