利用TG-DSC、XRD、SEM等多种手段研究煤灰的熔融特性

【作者】 邓芙蓉；

【导师】 赵虹； 杨建国；

【作者基本信息】 浙江大学 ， 工程热物理， 2005， 硕士

【摘要】 锅炉结渣长期以来一直成为困扰燃煤电厂安全、高效、经济运行的严重问题,锅炉的结渣与煤质特性、锅炉设计和运行等方面的因素有关,但是对于同一台锅炉,同样的运行条件下,煤质特性对锅炉结渣的影响最大,而煤灰的本身的熔融特性成为判断锅炉结渣的重要依据。目前在各种判断煤灰结渣倾向的方法里,煤灰的熔融性仍然是一个非常重要的指标,判断的分辨率在单因素判别法中最高,说明煤灰的熔融特性和结渣有着密不可分的联系。本文通过热分析、X-射线衍射物相分析、扫描电子显微镜和电子能谱多种分析手段对刘家渠、温家梁和新庄三种煤灰的熔融特性进行了研究,并对其熔融机理做了分析。 本论文的主要内容如下: 1.首先阐明了燃煤发电在我国电力生产中的重要地位以及因燃煤而引起的锅炉结渣对电厂生产的危害,并进一步说明了煤灰的熔融性和锅炉结渣的关系。 2.描述了国内外对煤灰熔融特性研究的现状和进展。并从煤灰熔融的物理特性、煤灰成分、煤中矿物组成与煤灰熔融特性的关系三个方面分别总结了国内外的研究成果和研究方法,并重点介绍了国外利用热分析法对煤灰熔融特性的研究。 3.利用热重法和差示扫描量热法(TG-DSC)对刘家渠、温家梁、新庄三种煤的高温灰的熔融特性进行了研究。对TG曲线的失重原因及DSC曲线上每个特征峰的成因进行了详细的分析。 4.利用X-射线衍射物相分析仪,对温家梁、新庄灰加热到DSC曲线上的特征温度的灰渣样进行了定性分析。通过各种矿物的X-射线衍射强度随温度的变化曲线,对两种煤灰样的主要矿物质在加热过程中热行为进行研究。 5.利用扫描电子显微镜对两种煤灰各个特征温度下的灰渣样进行扫描,对不同温度的灰渣形貌特征进行了研究,并利用电子能谱对扫描照片中的具有不同形貌特征的部分进行能谱分析以区别不同形貌特征部分的元素组成差异。更多还原

【Abstract】 Slagging has always been one of the most serious problem that affet the security、 economy、 efficiency of the coal burned boiler power plants. Coal quality, boiler design , as well as the operation condition are all related to boil slagging. But if the boiler and operation condition keep the same , the coal quality then become the primary factor affecting the boiler slagging and the coal ash fusibility then become an important attribute that predict the boiler slagging trends. At present, the highest reliability of fusibility as an import predict index among the all kinds of single indexes predicting the slagging trend , indicate that the ash fusibility has a close relation with the boiler slagging. This paper studied the fusibility, further the fusion mechanism of three coal ash , liujiaqu, wenjialiang and xinzhuang with thermal analysis, X-ray diffraction and Scanning electron microscope.Main contents of this paper are as following:1. To begin with ,explained the importance of coal resource to electric power production and what the slag will do harm the electric power production. Further explained the relation between the coal ash fusibility and boiler slagging.2. Described the actuality and development of the research of the coal ash fusibility. respectively Summarized the research results and research methods ,both domestic and overseas of coal ash fusibility according to the relations the coal ash fusibility with the ash fusion physical characteristic, with the chemical composition and with mineral composition. Emphasesed the research results overseas conducted by thermal analysis.3. Studied the fusibility of three coal ash , liujiaqu, wenjialiang and xinzhuang with differential scanning calorimetry and thermogravimetry and analyzed the causes of formation of characteristic peaks on the DSC curves .4. Studied the mineral behaviour of wenjialiang and xinzhuang coal ash with X-ray diffraction qualitative analysis .5. Scanned the coal ahs sample that made at each characteristic temperature according to DSC curve . studied the appearance characteristics of different ash samples even the different parts of the same sample and analyzed the difference of element composition.更多还原