【作者】 惠兵；

【导师】 潘兰英； 焦红光；

【作者基本信息】 河南理工大学 ， 矿物加工工程， 2010， 硕士

【摘要】 随着煤炭开采机械程度的提高及地质条件的变化,原煤中细粒含量越来越多,细粒分选成为关注的焦点。综合比较当前细粒煤分选技术,流化床分选以其独特优点被广泛采用,但却存在分选粒度范围窄、可控可调参数少等缺陷。针对其存在的缺陷,设计研发一种阻尼脉动细粒煤干扰床分选技术及装备,以适应煤质的多变。干扰沉降理论是设备研发的理论基础。在颗粒受力分析及沉降末速计算基础上,首先选取了沉降速度模型,进而对脉动干扰沉降理论做了初步探讨。分析了沉降速度与其影响因素之间的关系及干扰沉降末速经验式中的n值。分析发现:沉降速度均随颗粒粒度(密度)的增大而增大,随入料浓度的增大而减小;n值随颗粒密度、粒度的增大都呈减小的趋势,n值随颗粒密度增大的变化较为平缓,随粒度增大其变化较为剧烈且呈指数衰减趋势。在此基础之上,提出了新的设计思路,即:增设脉动水流以强化分选过程中的密度效应,在分选腔内布置阻尼块来改善流场,采取单边入料来延长颗粒分选时间。通过Pro/E软件建模、FLUENT流场模拟优化了分选机结构,制作了实验室样机并构建了实验系统。采取不同矿区煤样,分别作了对比试验、影响因素的正交试验。实验结果表明:阻尼脉动干扰床分选效果优于传统干扰床分选机;正交试验找出了影响分选效率的显著因素,并得到了试验回归方程。更多还原

【Abstract】 With the change in the mechanical mining and geological conditions, more and more fine coal exist in the raw coal, and its separation has become a focus of attention. By comprehensive comparison of various fine coal separation technology, Fluidized bed separation was widely used for its unique advantages, But there were less controllable parameters, narrow grained separation etc, defects. According to the problems, the Damping pulse jamming-bed separation technology was designed, in order to accommodate frequency change of coal quality.Designing of equipment was based on the hindered settling theory. With analysis of forces on particle and calculation of terminal velocities, terminal velocity models are selected, and then Pulse jamming settlement theory was discussed. The relationship between settling velocity and its effect factor, n-value of experimental-formula for hindered settling velocity were analysed. The analysis show that the settling velocity increases with the size and density increasing, decreases with the concentration increasing; n-value decreases with the size and density increasing; the n-value versus size relationship follows an exponential decay curve, but hardly change with the size increasing.Based on the theory, the new design was raised, i.e., adding pulsatingcurrent to strengthen density effects, adding damping block to improve the flow field, adding one-sided in-put to extend separation time. The seperator and experimental system were built, and the structure of seperator was optimized by modeling and flow field simulation. The contrast-test and orthogonal test for factors were conducted by using coal samples from different mining area. The results indicated: Damping pulse jamming bed separator was superior to the traditional fluid-bed separator, orthogonal test found the marked factors of separating efficiency and established regression equation.更多还原