Abstract
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°C 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 size get 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 PM1.0 falls significantly short of their corresponding content in the entire ash, which indicates that PM1.0 may be formed via a vaporization-condensation mechanism.