双溢流管煤泥旋流重选柱溢流结构的优化研究

发布时间：2018-05-25 01:28

本文选题：双溢流管 + 煤泥旋流重选柱　；参考：《太原理工大学》2015年硕士论文

【摘要】：为了能够改善煤泥旋流重选柱只出两产品的局限性，同时提高精煤产率，采用在煤泥旋流重选柱内部插入一根同心上溢流管，变原溢流管上出口结构为切向侧出口结构，形成新的粗煤泥分选旋流器—双溢流管煤泥旋流重选柱。对双溢流管煤泥旋流重选柱的操作参数和溢流结构进行了优化研究，并进行了某一结构下的粗煤泥分选效果评定。运用计算流体动力学软件Fluent对不同上溢流管内径的插入深度下的旋流器流场进行了数值模拟，模拟结果较好的验证了试验结果。在不同的入料压力下进行了粗煤泥分选试验，将不同压力下得到的三产品按粒级计算分配率并化验灰分。试验结果表明溢流和侧溢流产品灰分会随入料压力的增加先减少后增加，过大的入料压力会导致物料中粗粒级磨损严重。在不同的侧溢流进料管长度下进行了粗煤泥分选试验，将不同侧溢流进料管长度下得到的三产品按粒级计算分配率并化验灰分。试验结果表明增加侧溢流进料管长度会提高三产品的灰分，为保证溢流、侧溢流和底流的灰分都达到比较满意的效果，保持侧溢流进料管长度在190mm最合适。在不同的上溢流管插入深度和内径下进行了粗煤泥分选试验，将得到的三产品按粒级计算分配率并化验灰分。试验结果表明随着上溢流管插入深度的增加，各产品灰分先降低后增加，随着上溢流管内径的增加，上溢流管的作用由分级为主逐步变为分选加排细。其中内径的作用要大于插入深度，，且更具有规律性。在不同的侧溢流口结构下进行了粗煤泥分选试验，将不同侧溢流口结构下得到的三产品按粒级计算分配率并化验灰分。试验结果表明对侧溢流口减压会导致底流中更多的中低灰物料随溢流或侧溢流排出，使溢流灰分不合格。进行了三产品分选效果评定，试验结果如下：＞1mm粒级的分选密度为1.483g/cm3,可能偏差为0.103，不完善度为0.212；1-0.5mm粒级的分选密度为1.638g/cm3,可能偏差为0.222，不完善度为0.348；＞1mm粒级的分选密度为1.852g/cm3,可能偏差为0.278，不完善度为0.326。运用计算流体动力学软件Fluent对旋流器内流场进行了数值模拟，模拟结果表明上溢流管内径的改变会影响旋流器内流场的各速度分布，其中对切向速度和轴向速度影响最为明显，而这两种速度是物料在径向上的分层和轴向上的分离的重要原因；上溢流管插入深度的改变对旋流器流场的影响不及内径，且其变化规律并非单调，在L=65mm时轴向速度略有降低，这可能是为何在试验中底流各粒级分配率会突然降低的原因。
[Abstract]:In order to improve the limitation of only two products produced by slurry cyclone gravity separation column and increase the yield of clean coal, a concentric upper overflow pipe was inserted into the coal slurry swirl gravity separation column to change the outlet structure of the original overflow pipe to tangential side outlet structure. A new coarse slime separation cyclone-double overflow pipe slime cyclone was formed. The operation parameters and overflow structure of double overflow pipe slime cyclone gravity separation column were optimized and the separation effect of coarse coal slime was evaluated under a certain structure. The flow field of hydrocyclone with different insertion depth of upper overflow tube was simulated by using the computational fluid dynamics software Fluent. The simulation results verified the experimental results well. The coarse coal slime separation test was carried out under different feed pressure. The distribution rate and ash content of the three products obtained under different pressure were calculated according to particle level. The results show that the ash content of overflow and side overflow products decreases first and then increases with the increase of feed pressure. The coarse coal slime separation test was carried out at different length of side overflow feed pipe. The distribution rate of three products under different side overflow feed pipe length was calculated according to particle level and ash content was tested. The test results show that increasing the length of the side overflow feed pipe will increase the ash content of the three products. In order to ensure the overflow, the ash content of the side overflow and the bottom flow can reach satisfactory results, and the best way to keep the length of the side overflow feed pipe in 190mm is to ensure the overflow. The coarse coal slime separation test was carried out at different insertion depth and inner diameter of the upper overflow pipe. The distribution rate of the three products was calculated according to the particle level and the ash content was tested. The test results show that the ash content of each product decreases first and then increases with the increase of the insertion depth of the upper overflow pipe, and with the increase of the inner diameter of the upper overflow pipe, the function of the upper overflow pipe gradually changes from grading to sorting, adding and refining. The effect of the inner diameter is greater than the insertion depth, and it is more regular. The coarse coal slime separation test was carried out under different side overflow structure. The distribution rate and ash content of the three products obtained under different side overflow outlet structures were calculated according to particle level. The experimental results show that the decompression of the contralateral overflow outlet will lead to the discharge of more medium and low ash materials in the bottom flow with the overflow or the side overflow, which makes the ash content of the overflow unqualified. The evaluation of the separation effect of three products has been carried out. The results are as follows: the density of 1mm grain-grade is 1.483g / cm ~ (-3), the possible deviation is 0.103, the degree of imperfection is 0.212g / cm ~ (-3), the possible deviation is 0.222g / cm ~ (3), the imperfection is 0.348, the possible deviation is 0.278g / cm ~ (3), the imperfect degree is 0.326. The numerical simulation of the flow field in the hydrocyclone is carried out by using the computational fluid dynamics software Fluent. The results show that the change of the inner diameter of the upper overflow tube will affect the velocity distribution of the flow field in the cyclone, especially the tangential velocity and the axial velocity. These two kinds of velocities are the important reasons for the separation of the material in radial stratification and axial direction, the influence of the insertion depth of the upper overflow tube on the flow field of the hydrocyclone is less than that of the inner diameter, and the variation law is not monotonous, and the axial velocity decreases slightly at the time of L=65mm. This may be the reason why the distribution rate of the bottom flow decreased suddenly in the experiment.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD94

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