无烟煤流化床气化飞灰的结渣特性

通过烧结特性实验研究了无烟煤流化床气化飞灰在"近灰熔点"处的烧结特性,并利用X射线衍射分析(XRD)进行了结晶矿物质和玻璃相的定量分析以研究其烧结机制。结果表明,飞灰中矿物质间的相互转化控制着其结渣特性。由于铁、钙和镁等碱性组分的部分富集,飞灰的灰熔点与原煤相比要低;在低于灰熔点DT 100~200℃附近,由于长石类矿物质的转变熔融形成了具有黏结性的液相,灰样发生液相烧结导致收缩变形而结块;大部分的钙和铁等助熔组分赋存于玻璃相中提高了其浓度,且在热处理过程中它们并未发生析晶行为,从而促进灰样的烧结致密化过程,进一步使得飞灰的结渣倾向增强。

Slagging characteristics of fly ash from anthracite gasification in fluidized bed

An experimental procedure was tested for studying the sintering and fusion characteristics of fly ash from anthracite fluidized bed gasification at the temperature approaching the ash deformation temperature (DT), and the slagging characteristic was investigated. The quantitative analysis on the composition of crystalline mineral matter and the amorphous phases in the thermal treated ash was carried out using X-ray diffraction analysis (XRD). Experimental results show that the slagging tendency of fly ash is related to the transformation of minerals. AFTs of fly ash are lower than those of original coal due to higher contents of Fe, Ca, and Mg. The formation of melting matrix causes a liquid-phase sintering at 100~200℃ below the DT, which leads to a shrinkage deformation and clinkering due to the formation and transformation of feldspar that plays a 'glue’ role in sintering. A great amount of Ca and all of Fe are found in the glass phase, which improves the amorphous phase in concentration. These fluxing components in the glass phase that do not crystalize during thermal treatment can promote the densification process of sintering and the slagging or agglomeration tendencies.