混煤燃烧过程中矿物质的形态变化及相变

引　言炉内受热面结渣被认为是电站锅炉中最难以处理的一个问题 ,特别在我国长时间内煤粉锅炉作为主要的能源供应手段 .近年来 ,国内有许多电站采用混煤燃烧的方法以适应不同的要求 ,如减少结渣和ＳＯｘ 的排放 .然而 ,实际上如果混煤中设计使用的煤和实际使用的煤特性不一样 ,混煤燃烧可能会导致严重的结渣 .对单一煤种燃烧过程中的矿物质行为已经有了广泛研究1～ 4 ] ,但对混煤很少有研究5,6] .本文主要研究混煤燃烧后矿物质行为特性的变化 ,并用ＸＲＤ分析矿物质形态随温度的变化 ,从矿物学的观点来解释混合煤灰熔融特性 ,以揭示混煤结…

CONFORMATION CHANGE AND PHASE TRANSFORMATION OF MINERALS DURING COAL BLENDS COMBUSTION

In this paper,the ash fusion characteristics and mineral behavior of individual coal ash and a series of two-component blendsd ashes are studied.The samples are heated progressively from(IT)at 100?℃intervals in reducing atmosphere.Mineral composition and type at each temperature interval are determined by X-ray diffraction (XRD)analysis.For different coal ashes,the main mineral matter at 800?℃is quartz,anhydrite and hematite,calcite and feldspar.With increasing temperature,oxidation,thermal decomposition,transformation and reaction occur between the components.It can be seen that quartz,anhydrite decrease and anorthite,gehlenite increase.At about 1200?℃,all of mineral diminish and a glass phase is formed.Some combinations of mineral in component coal produce low-melting eutectic composition at a high temperature and this is the main reason causing the non-arithmetic average of softening temperature of blends ash.