Experimental Study Of Zhundong Coal Ash Melting Characteristics Under Reducing Atmosphere Condition

Coal is abundant in China，especially in Zhundong. In this days, under thecondition of environmental pressure is more and more big, in order to useZhundong Coal clean and efficient，it is an inevitable choice to choose the coalgasification technology, and it is also essential to do research for meltingcharacteristic of Zhundong coal in reducing atmosphere. This paper research themelting characteristic of Zhundong coal in reducing atmosphere at cooling phase.Then compare Zhundong Coal with other two coal, in order to find out differentcomponents of coal ash for the melting characteristic in reducing atmosphere bycoal ash fusion characteristic experimental facility.The result of different quench temperature and cooling rate from sample ofZhundong coal ash showed that a Temperature range exist that had a high Crystalcrystallization rate at the sample of melten slag precipitated crystals in the processof cooling quench, which about800℃~1200℃by Zhundong coal. When the moltenash samples separated out crystals, a phenomenon called Isomorphous came intobeing, which lead to the existence of Mg contained Gehlenite. Throughout theprocess, the framework constructed by precipitated crystal substances in moltenvitreous,and low temperature eutectic material filled up the pore structure betweenthe crystals framework. With the higher alkali metal content, the less pore structureand more smooth of ash sample surface topography.Experimental results about three kinds of ash components under the sameconditions of temperature show that the content of CaO directly affect the maintypes of crystals substances in coal ash. The higher content of CaO in coal ash, themore easily precipitated crystals which had Ca elements relatively high proportionof ash. For example, three kinds of coal ash samples separated out Mullite(3SiO2.2Al2O3), anorthite (CaAl2Si2O8) and gehlenite (Ca2Al2SiO7). The resultsalso showed that the presence of SiO2will produce more vitreous ash component,capable of reducing the crystallization rate of the crystals. Alkali metal and alkaline earth metal is the opposite. Zhundong coal ash crystallization rate is larger than theother two coal.Under the same condation of quenching temperature, Zhundong coalhad a higher degree of crystallinity, and ash made more stable physical andchemical properties, which in order to analyze the characteristics of slagging andcontamination from the point of the degree of crystallization crystals.