选粉机分级特性与窄粒径产品制备的研究

发布时间：2018-05-11 21:31

本文选题：选粉机 + 分级特性　；参考：《西南科技大学》2015年硕士论文

【摘要】：窄粒径产品由于具有特殊的性能而被广泛的运用,为了满足对窄粒径产品的广泛需求,解决窄粒径产品的制备的问题就显得尤为重要。利用选粉机制备窄粒径产品的关键点是:选粉机的分级性能和制备工艺。本文在利用数值模拟研究选粉机分级特性的基础上,对选粉机的参数进行改进,以提高选粉机的分级性能;采用两次分级的方法来制备窄粒径产品,并研究了工艺参数对产品粒径分布的影响。由气相特性显示选粉机的流场存在的不足:工艺参数不匹配时,叶片间存在旋涡;转速变动,叶片间回流加剧;下锥体速度分布较低,选粉机再次分级能力较弱;蜗壳内部湍流较强和转笼高度不合理,能量损失严重。对选粉机的结构参数和工艺参数进行优化,以改善其分级性能。工艺参数方面,对选粉机的转速和风速进行合理匹配。结构参数方面,对叶片结构、下锥体、蜗壳、转笼高度进行优化改进。相对改进前,改进后选粉机的流场更加稳定均匀,模拟分级效率曲线与理论分级曲线更加接近。在两次分级的基础上制备窄粒径产品,可以通过调节两台选粉机的转速来实现。同时增大或者减小两台选粉机的转速,窄粒径产品可以在保持较窄粒径分布范围的条件下,平均粒径增大或者减小。在风速不变时,窄粒径产品粒径的分布由一、二次选粉机的转速差决定。随着转速差的减小,粒径分布曲线变窄。二次风速对改善窄粒径产品的粒径分布具有重要意义。随着二次风速的增大,重质碳酸钙和水泥生料对应的产品的粒度分布曲线都变窄,水泥生料的粒度分布曲线比重质碳酸钙的更窄。
[Abstract]:Narrow size products have been widely used because of their special properties. In order to meet the wide demand for narrow size products, it is particularly important to solve the problem of the preparation of narrow size products. The key points of preparing narrow particle size products by using separator are: classifying performance and preparation technology of the separator. On the basis of the numerical simulation study on the classification characteristics of the separator, the parameters of the separator are improved in order to improve the classification performance of the separator, and the narrow particle size products are prepared by the method of twice classification. The effect of process parameters on particle size distribution was studied. The gas phase characteristics show that there are shortcomings in the flow field of the separator: the vortex exists between the blades when the technological parameters are not matched, the speed changes, the reflux between the blades intensifies, the velocity distribution of the lower cone is lower, and the classifier is weak again. The turbulence in the volute is strong, the height of the cage is unreasonable, and the energy loss is serious. The structural and technological parameters of the separator were optimized to improve its classification performance. In terms of process parameters, the speed and wind speed of the separator are reasonably matched. In terms of structural parameters, the blade structure, lower cone, volute and cage height are optimized and improved. Before the improvement, the flow field of the improved separator is more stable and uniform, and the simulated classification efficiency curve is closer to the theoretical classification curve. The narrow particle size product can be prepared by adjusting the speed of the two separators on the basis of two grades. At the same time, by increasing or decreasing the rotating speed of the two separators, the average particle size of the products with narrow particle size can increase or decrease under the condition of keeping a narrow particle size distribution range. When the wind speed is constant, the particle size distribution of narrow particle size products is determined by the speed difference of primary and secondary separators. With the decrease of rotational speed difference, the distribution curve of particle size becomes narrower. The secondary wind speed plays an important role in improving the particle size distribution of narrow-diameter products. With the increase of the secondary wind speed, the particle size distribution curves of heavy calcium carbonate and cement raw meal become narrower, and the particle size distribution curve of cement raw meal is narrower than that of calcium carbonate.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.8

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