【作者】 张龙；

【导师】 黄镇宇； 王智化；

【作者基本信息】 浙江大学 ， 能源环境工程， 2015， 硕士

【摘要】 煤炭依旧会是我国未来的支柱能源,煤炭的利用离不开煤灰熔融特性的研究。在电站锅炉中,为减少锅炉结渣,通常要求入炉煤具有较高的灰熔点。而在煤气化领域,采用液态排渣的气流床气化炉为顺利排渣,对煤灰的高温粘度特性有严格的限制,一般都要求较低的灰熔点。为满足不同行业的实际需求,需要采用多种调控手段调节煤灰熔点。本文选用目前储量较大,应用广泛的准东煤和准格尔煤为研究对象,测试了不同比例的配煤后煤灰的熔融特性变化,灰样熔点随准格尔煤比例的升高呈现先降低后升高的特点。结合X射线衍射技术和FactSage模拟计算,分析煤灰中矿物转化过程,从微观机理上解释了引起一系列煤灰熔点变化的原因。并发现了几组重要的低温共熔体,正是这些低温共熔体的形成与共熔导致了煤灰在升温过程中液相的生成,组成低温共熔体矿物含量的不同会导致这些矿物不同程度的熔融,并对其他的矿物质产生一系列影响。针对目前普遍存在的基于化学元素组成来指导灰熔点调控的现象,本文通过配煤和加入添加剂合成出几种元素组成相同的煤灰,并研究它们的熔融特点。发现这几种煤灰的灰熔点存在较大的差异,并进一步利用XRD和SEM-EDX结合的方式对不同温度阶段的灰样进行实验分析。结果表明：决定煤灰高温时矿物组成的因素除了煤灰元素组成还有这些元素最初在煤灰中的赋存状态,即单纯的依据元素组成来预测灰熔点指导灰熔点调控是不准确的,并对以后灰熔点预测模型的搭建提出合理的建议。更多还原

【Abstract】 The coal resource will still play a dominant role in domestic energy industry in the future. In terms of utilization of coal, it is indispensable to study the coal ash fusion characters. In general, pow plants’boilers to avoid slagging demand the coal transported into furnace with higher ash fusion temperature. While the entrained-flow coal gasifier in order to discharge the slag have a strict requirement on ash fusion. Traditionally, the coal with lower ash fusion temperatures (AFTs) is better. Therefore, it is necessary to adopt diverse methods to regulate AFTs to cater to different industrial requirements.This thesis chose the Zhungeer coal and Zhundong coal as the experimental resource, which both have a large reserve in China and are used widely. Blend the two kind of coals getting five synthetic coals in order of different blending ratio. The AFTs have been measured respectively. The blended ash AFTs pattern illustrated the figures were in a downward trend, then in a upward trend. The X-ray diffraction (XRD) technology and FactSage calculating soft package were used to research the ash mineral transformation occurred in heating progress, to reveal the cause leading the trend. The analysis result found several important eutectic melting (EM). It’s the EM appearing and disappearing progress increases the liquid phase in ash slag causing the ash melting. The quantity of mines constructing the EM is responsible for the mineral melting degree, and have a series of effects on other mines.Current regulations of AFTs are all according to the element compositions. While the predicting based on element compositions normally is not too precise and widely adapted. By blending and adding additive, the article studied several ash samples with a similar element compositions to investigate the internal reason. Although these ash samples’element compositions are same, their AFTs still exist big difference. The XRD and scanning electron microscope combined with Energy Dispersive X-ray Detector (SEM-EDX) were used to undertake the further study. The experimental consequence indicate that there are two factors determining the AFTs. Not only the primary chemical elements, but also the the occurrence in minerals of chemical elements play the important role in coal ash ATFs.更多还原