小龙潭褐煤灰熔融特性影响因素的研究

为优化流化床的工艺条件,研究了粒径大小、气氛、残炭含量对小龙潭褐煤灰熔融特性的影响。采用化学分析法和X射线衍射法(XRD)从煤灰化学组成和矿物质演变的角度分析引起灰熔点变化的原因。结果表明:灰熔点随颗粒的增大先增大再减少是由煤灰中总碱量的变化引起的;测试气氛导致灰熔点差异是由于在弱还原气氛下方铁矿与钙长石反应生成了铁尖晶石、铁橄榄石等低熔点物质的缘故;残炭含量不同导致灰熔点的变化是因为Fe_3C的生成、灰锥内局部还原性气氛以及残炭的"骨架"作用引起的。 In order to optimize the operating conditions of lignite fluid-bed gasification,the influence of particle size,atmosphere condition and residual carbon content on the fusion characteristics of Xiaolongtan lignite ashes are investigated.The issues that lead to the variation of ash fusion temperature (AFT) are analyzed from the aspects of ash composition and mineral transformation using chemical analyses and XRD measurement.Results show that the change of AFT caused by particle sizes is due to the variation of total alkali content in ashes;the modification of AFT in different atmospheres results from the generation of low melting point fayalite and hercynite under weak reducing atmosphere,which come from the reactions between the wustite and anorthite;the difference of AFT caused by residual carbon content is the result of the formation of Fe_3C,reducing atmosphere and the "skeleton" of residual carbon within the ashes cone