可视化的煤灰高温流动特性试验研究
Experimental study on high temperature flow characteristics of coal ash
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摘要: 煤灰渣的流动特性是影响液态排渣的重要因素之一,为了确保液态排渣的顺利进行,充分 了解相关灰渣在高温下的熔融及流动特性是很有必要的。 本研究的主要目的是开发一种可以用于 煤灰的高温流动特性的可视化测量方法,以便对试验煤灰的流动特性进行更多的了解。 提出的可 视化测量方法中,采用 CCD 相机对将二煤灰、塔城煤灰以及准东煤灰的整个流动过程进行了实时 监测,并结合了 MATLAB 等图像处理软件获得了各煤灰样品的流动长度、流动速度对温度的变化 结果。 在该可视化测量方法中,灰渣样品预先被热处理后粘附在刚玉片上,然后采用倒挂流动的形 式进行试验。 试验中灰渣样品的流动减少了基板的接触,流动阻力得到了优化。 此外,可以通过图 像处理得到灰渣的各种形态参数,结合多个参数进行高温流动特性的综合考量。 为了验证试验结 果的可靠性,还借助了 FactSage 软件计算了不同温度下煤灰的黏度,并将计算结果与试验结果进行 了比对分析。 研究结果表明,3 种煤灰中将二煤的流动性能相对最差,其他 2 种煤灰的流动性则更 为接近。 获得了各个样品的黏度特征温度和流动特征温度,将二煤、塔城煤和准东煤样品的特征黏 度温度 T25分别为 1 324,1 302 和 1 298 °C,而 3 种煤的临界流动温度 TC 分别为 1 299,1 282 和 1 279 °C。 上述的特征温度结果可为相关领域的工作人员提供一定的参考信息。 矿物分析表明煤 灰烧结过程形成了低熔点的蓝方石,蓝方石的熔融使得煤灰的流动性得到一定的促进,而形成的高 熔点镁系矿物(镁黄长石、镁铁尖晶石等)则抑制了煤灰流动。 总体而言,通过对流动试验与黏度 计算结果的比对分析,该可视化测量方法的测量结果与黏度结果较为吻合,某种程度上证实了该方 法的有效性。Abstract: The flow characteristics of coal ash is one of the important factors affecting liquid slag discharge. To en⁃ sure the smooth process of liquid slag discharge,it is necessary to fully understand the melting and flow characteristics of relevant ash at high temperature. The main purpose of this study is to develop a visual measurement method for the high temperature flow characteristics of coal ash,to understand more about the flow characteristics of experimental coal ash.In the visualization measurement method proposed in this paper,the CCD camera was used to moni⁃ tor the whole flow process of the Jianger coal ash,Tacheng coal ash and Zhundong coal ash in real time,and the flow length and flow velocity of each coal ash sample were obtained by using MATLAB and other image processing software. The cinder sample was adhered to the corundum sheet after heat treatment in advance,and then the experiment was carried out in the form of inverted flow. In the experiment,the contact of substrate was reduced by the flow of ash sample,and the flow resistance was optimized. In addition,various morphological parameters of ash could be obtained by image processing,and the high-temperature flow characteristics could be comprehensively considered by combi⁃ ning multiple parameters. To verify the reliability of the experimental results,the FactSage software was used to calcu⁃ late the viscosity of coal ash at different temperatures,and the calculated results were compared with the experimental results.The results show that the Jianger coal has the worst fluidity among the three kinds of coal ash,while the fluidi⁃ ties of the other two kinds of coal ash are closer.The characteristic viscosity temperature and flow characteristic temper⁃ ature of each sample were obtained. The characteristic viscosity temperature T25 of Jianger coal,Tacheng coal and Zhundong coal samples were 1 324,1 302,1 298 °C respectively,while the critical flow temperature TC of the three coals were 1 299,1 282,1 279 °C respectively.The above characteristic temperature results can provide some ref⁃ erence information for the work in related fields.Mineral analysis shows that the sintering process of coal ash forms blue marble with low melting point,and the melting of blue marble promotes the flow of coal ash to a certain extent, while the formation of high melting point magnesium minerals (magnesia anorthoxite,magnesia spinel,etc.) inhib⁃ its the flow of coal ash.In general,by comparing the flow experiment and viscosity calculation results,the measurement results of the visual measurement method are in good agreement with the viscosity results,which confirms the effective⁃ ness of the method.