永磁场调控重介旋流器分选密度的磁系优化研究

发布时间：2019-01-08 07:24

【摘要】：作为一种高效的分选设备，三产品重介旋流器在选煤行业得到了广泛的应用。然而三产品重介旋流器二段分选密度难以在线调控的技术难题一直是选煤工业中亟待解决的核心问题。本论文利用钕铁硼永磁体构建径向永磁场作用于重介旋流器，进行了永磁场调控重介旋流器分选密度的磁系优化研究。研究了四磁极交替（N-S-N-S）对称布置的二倍磁系和六磁极交替（N-S-N-S-N-S）对称布置的三倍磁系作用于重介旋流器不同位置时的介质分配规律。研究表明：二倍磁系和三倍磁系永磁场的设置，能够影响旋流器的介质分配，随着磁系厚度的增加，溢流密度和底流密度变化更明显。进行了二倍磁系作用于重介旋流器溢流管、圆柱下端、锥部上端、锥部中间、锥部下端和底流口时的粗煤泥分选试验，研究了不同磁系厚度的二倍磁系作用于旋流器不同位置时对其分选密度的影响规律。研究表明：二倍磁系作用于溢流管能够降低旋流器的分选密度；作用于底流口能够提高旋流器的分选密度；作用于旋流器圆柱下端和锥部上端时，永磁场作用会破坏旋流器的正常分选；作用于锥部下端时，调控效果最佳，随着磁系厚度的变化，能够实现分选密度的双向调控。进行了三倍磁系作用于重介旋流器溢流管和锥部下端的粗煤泥分选试验，研究了不同磁系厚度的三倍磁系作用于旋流器不同位置对其分选密度的影响规律。研究表明：三倍磁系永磁场作用于溢流管能够降低旋流器的分选密度，且作用效果比二倍磁系更好；作用于锥部下端时，随着磁系厚度的变化，也能够实现分选密度的双向调控。设计了I号齿板和II号齿板，与钕铁硼永磁体有效结合，构建了两种四磁极交替布置的高梯度磁系，并利用高梯度磁系作用于旋流器溢流管、锥部下端和底流口，研究了不同磁系厚度的高梯度磁系永磁场对作用于旋流器不同位置时的介质分配规律。研究表明：两种高梯度磁系永磁场的设置，，也能够影响旋流器的介质分配，随着磁系厚度的增加，溢流密度和底流密度变化更明显。进行了I号齿板和II号齿板高梯度磁系作用于重介旋流器溢流管、锥部下端和底流口的粗煤泥分选试验，研究了不同磁系厚度的两种高梯度磁系作用于旋流器不同位置对其分选密度的影响规律。研究表明：作用于底流口时，高梯度磁系作用效果比普通二倍磁系作用效果更好，且I号齿板高梯度磁系优于II号齿板高梯度磁系。借助ANSYS软件的电磁场分析功能，研究了二倍磁系、三倍磁系的磁场特性。模拟结果表明：磁系厚度越大，磁系颗粒所受磁场力越大，且三倍磁系比二倍磁系的磁力线分布更均匀、更密集，更又有利于磁性颗粒的吸附。模拟结果初步揭示了永磁场调控重介旋流器分选密度的原因在于永磁场的设置强化了磁性颗粒向旋流器内壁的运移和富集。
[Abstract]:As an efficient separation equipment, three-product heavy-medium cyclone has been widely used in coal preparation industry. However, the technical problem that the two-stage separation density of three-product heavy media cyclone is difficult to control on line is always the core problem to be solved urgently in coal preparation industry. In this paper, the radial permanent magnetic field is used to construct a radial permanent magnetic field to control the separation density of the heavy medium cyclone, and the optimization of the magnetic system is carried out. The dielectric distribution law of the double magnetic system with four pole alternating (N-S-N-S) symmetry arrangement and the triple magnetic system with six magnetic pole alternation (N-S-N-S) symmetry arrangement with different positions is studied. The results show that the permanent magnetic field of the secondary and triple magnetic systems can affect the distribution of the medium of the cyclone. With the increase of the thickness of the magnetic system, the overflow density and the bottom current density change more obviously. The separation tests of coarse coal slime on the overflow tube, the lower cylinder, the upper end of the cone, the middle of the cone, the lower end of the cone and the bottom outlet of the double magnetic system are carried out. The influence of double magnetic system with different thickness of magnetic system on the separation density of hydrocyclone is studied. The results show that the separation density of cyclone can be reduced by the action of double magnetic system on overflow tube, and the separation density of cyclone can be increased by acting on bottom flow port. When acting on the lower end of the cylinder and the upper end of the cone, the permanent magnetic field will destroy the normal separation of the cyclone, and when acting on the lower end of the cone, the control effect is the best, and with the change of the thickness of the magnetic system, the bidirectional control of the separation density can be realized. The separation experiments of coarse coal slime with triple magnetic system acting on the overflow tube and the lower end of the cone are carried out, and the influence of different magnetic system thickness on the separation density of the cyclone is studied. The results show that the separation density of cyclone can be reduced by the permanent magnetic field acting on the overflow tube, and the effect is better than that of the double magnetic system. When acting on the lower end of the cone, the separation density can be controlled bidirectional with the change of magnetic system thickness. I tooth plate and II tooth plate are designed and combined effectively with NdFeB permanent magnet. Two kinds of high gradient magnetic systems with alternating magnetic poles are constructed, and the high gradient magnetic system is applied to the overflow tube of cyclone, the lower end of cone and the bottom flow port. The dielectric distribution law of high gradient magnetic system permanent magnetic field pair acting on different positions of hydrocyclone with different thickness of magnetic system is studied. The results show that the permanent magnetic field of the two high gradient magnetic systems can also affect the dielectric distribution of the hydrocyclone. With the increase of the thickness of the magnetic system, the overflow density and the bottom current density change more obviously. The separation tests of coarse coal slime with I tooth plate and II tooth plate high gradient magnetic system on overflow tube, lower cone end and bottom flow port of heavy dielectric cyclone were carried out. The influence of two kinds of high gradient magnetic systems with different thickness of magnetic system on the separation density of hydrocyclone was studied. The results show that the effect of high gradient magnetic system is better than that of ordinary double magnetic system when acting on the bottom flow, and the high gradient magnetic system of I tooth plate is better than that of II tooth plate high gradient magnetic system. With the help of the electromagnetic field analysis function of ANSYS software, the magnetic field characteristics of the double magnetic system and the triple magnetic system are studied. The simulation results show that the greater the thickness of the magnetic system, the greater the magnetic force of the magnetic system particles, and the distribution of the magnetic force line of the triple magnetic system is more uniform, denser and more favorable to the adsorption of magnetic particles than that of the double magnetic system. The simulation results show that the permanent magnet field controls the separation density of the heavy medium cyclone because the permanent magnetic field enhances the migration and enrichment of magnetic particles to the inner wall of the cyclone.
【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】：TD455

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