叶轮转速和充气量对宽粒级煤泥浮选行为影响的初步研究

发布时间：2018-06-07 05:33

本文选题：浮选 + 叶轮转速　；参考：《太原理工大学》2015年硕士论文

【摘要】：煤炭洗选是实现煤洁净利用的第一步，煤炭通过洗选，可以提高煤炭质量，，减少燃煤污染物的排放；提高煤炭利用效率，节约能源。在矿物的加工和分选中，浮选是众多煤炭洗选方法中的一种，在国内外应用广泛，同时也是处理细粒级煤泥最有效的方法。本文以小于1.0mm的粗煤泥为研究对象，对试样进行按粒度按密度分级，通过实验室单元浮选试验以及窄粒级浮选动力学试验的方法，精细的研究了叶轮转速和充气量对宽粒级煤泥及浮选动力学常数的影响，系统的进行了相关分析。结合理论分析和实验数据进一步探讨和论证了叶轮转速和充气量以及煤泥的密度、粒度对浮选过程的影响。用MATLAB对试验条件与浮选速率常数进行了回归分析。通过FLUENT流体动力学模拟软件模拟浮选槽内部的气液两相流场及湍流度，解释了叶轮转速以及浮选槽充气量对粗煤泥浮选的影响。通过实验室自制的充气搅拌式浮选机，规格为1L。进行了相关实验室单元浮选试验，考察了充气量以及叶轮转速对粗煤泥产率以及可燃体回收率的影响，结果表明：在叶轮转速一定的条件下。精煤产率随着充气量的增大而增加，并在充气量到400L/h时，各个转速情况下的精煤产率到达最大。叶轮转速对浮选行为影响也较为明显，随着叶轮转速的增大，精煤的可燃体回收率和产率也会增加，但是，过大的叶轮转速不利于浮选。相对于充气量对浮选指标的影响，叶轮转速对浮选精煤的产率和可燃体回收率影响更为显著。可见，叶轮转速是浮选效果好坏的决定性因素之一通过实验可知，实验所用窄粒级煤泥的浮选过程符合一级动力学方程。浮选机叶轮转速对细粒级、低密度级煤泥的浮选速率常数k影响巨大。当叶轮转速增加时，浮选速率常数会增大；如果叶轮转速过大，浮选速率常数的数值反而会下降。但是，较高的叶轮转速会提高大密度、大粒度颗粒的浮选速率常数。故在浮选过程中，并不是叶轮转速越大越好。另外，煤泥颗粒对浮选速率常数也有较大的影响，当煤泥颗粒增大时，浮选速率常数会逐渐减小。通过实验结果可以看出，浮选速率常数k受颗粒的粒度、密度以及浮选机的叶轮转速的影响。试验数据通过数值计算软件MATLAB分析并建立了浮选速率常数k与这些参数之间的多元线性模型。同时，从流场的气液两相湍流度的角度分析了浮选槽中叶轮转速和通气量对浮选过程的影响。通过流体动力学软件FLUENT模拟了浮选槽内部的流场，直观的表现出浮选槽内部的湍流度和气液两相云图。从模拟云图以及试验数据可知，过大的充气量会加大浮选槽液面的湍流度，对粗颗粒而言，会降低其附着概率，不利于粗颗粒的浮选。当叶轮转速增大时，转子区域的湍流度会大幅增大，但是过大的转速，会使浮选槽内湍流度过大。因此，合适的叶轮转速将会提高颗粒的碰撞和附着概率，这也会有利于增大颗粒和气泡的矿化概率。浮选动力学的特性分析表明，在其他变量不变时，在相对较大的叶轮转速（800r/min）以及较低的充气量（400L/h）有利于提高粗煤泥的回收率和可燃体回收率。通过数值模拟软件，建立起浮选速率常数的模型，并通过这个模型，揭示了浮选速率常数与叶轮转速以及煤泥的密度、粒度之间的关系。
[Abstract]:Coal washing is the first step to realize the clean utilization of coal. Through washing, coal can improve the quality of coal, reduce the emission of coal pollution, improve the efficiency of coal utilization and save energy. In the mineral processing and selection, flotation is one of the many methods of coal washing, which is widely used at home and abroad, and is also the treatment of fine grained slime. The most effective method. In this paper, taking the coarse slime less than 1.0mm as the research object, the influence of the impeller speed and the inflating volume on the dynamic constant of the wide grain grade slime and flotation is carefully studied by the laboratory unit flotation test and the narrow particle flotation dynamic test. Correlation analysis. Combined with theoretical analysis and experimental data, the effects of impeller speed and volume, density of slime and particle size on the flotation process were further discussed and demonstrated. The regression analysis of the test conditions and the rate constant of flotation was carried out by MATLAB. The gas-liquid two phase flow field inside the flotation tank was simulated by FLUENT fluid dynamics simulation. And turbulence intensity, which explains the effect of impeller speed and the amount of aeration of flotation cell on coarse slime flotation.
The laboratory unit floatation test was carried out by a laboratory self-made aerated and stirred flotation machine. The effect of gas volume and impeller speed on the yield of coarse slime and the recoverable rate of the flammable body was investigated by 1L.. The results showed that the yield of refined coal increased with the increase of inflating volume and inflated under the condition of a certain impeller speed. When the speed of the impeller is measured to 400L/h, the yield of the refined coal reaches the maximum at every speed. The influence of the impeller speed on the flotation behavior is also obvious. With the increase of the impeller speed, the recoverable rate and the yield of the combustible body will increase. However, the oversize impeller speed is not favorable to the flotation. The yield of clean coal and the recovery rate of combustibles are more significant.
The experiment shows that the flotation process of the narrow particle slime used in the experiment is in accordance with the first order kinetic equation. The impeller speed of the flotation machine has great influence on the flotation rate constant k of the fine particle and low density grade slime. When the impeller speed increases, the flotation rate constant will increase; if the impeller speed is too large, the value of the flotation rate constant will drop. However, the higher impeller speed will increase the large density and the rate constant of large particle particles, so in the process of flotation, the higher the impeller speed is, the better the better. In addition, the slime particles have a great influence on the rate constant of the flotation. When the slime particles increase, the number of the flotation rate will gradually decrease.
The experimental results show that the flotation rate constant k is affected by the particle size, density and the impeller speed of the flotation machine. The experimental data is analyzed by the numerical software MATLAB and the multiple linear model between the flotation rate constant K and these parameters is established, and the floating rate is analyzed from the angle of the gas and liquid turbulent flow. The effect of impeller speed and aeration on the flotation process is simulated by the fluid dynamics software FLUENT. The flow field inside the floatation tank is simulated, and the turbulence in the flotation tank and the gas-liquid two phase cloud are displayed intuitively. From the simulated cloud chart and the experimental data, it is known that the excessive volume of gas will increase the turbulence of the floatation tank and the coarse particles. When the impeller speed increases, the turbulent degree of the rotor will increase greatly, but the excessive speed will make the turbulent flow in the flotation tank too large. Therefore, the appropriate impeller speed will increase the particle collision and the attachment probability, which will also help to increase the particles and the gas bubbles. Probability of transformation.
The characteristic analysis of the flotation kinetics shows that the relatively larger impeller speed (800r/min) and the lower gas volume (400L/h) are beneficial to the improvement of the recovery rate and the recovery rate of the flammable body when the other variables are constant. Through the numerical simulation software, a model of the constant number of floatation rate is established, and the flotation rate is revealed through this model. The relationship between constant and impeller speed and density and particle size of slime.
【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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