高含量重密度组分煤重介质旋流器分选特性研究

Study on Separation characteristics of dense medium cyclone for raw coal with high density fraction contents

为了提高重介质旋流器对高含量重密度组分难选原煤的分选效率,设计了新型重介质旋流器模型装置,建立了颗粒在离心旋转流场中沉降分离数学模型,采用试验与理论分析相结合的方法研究新型重介质旋流器的分选特性,揭示高含量重密度组分难选煤分选特性随工艺参数的变化规律,探索影响新型重介质旋流器流场工作悬浮液动态稳定性的因素及重产物排料输运机制。研究结果表明,新型重介质旋流器分选高含量重密度组分煤时,底流重产物排料能力强、处理量大;离心旋流场中的悬浮液密度梯度分布小、密度相对均匀,底流与溢流密度差值较低,流场中悬浮液稳定性更强;入料的压力与悬浮液动态稳定性、分选精度及重产物排料效率直接相关,随着入料的压力增大,底流、溢流口排出悬浮液密度差值增大,可能偏差E值降低,分选精度提高,重产物排出量升高;当入料的压力为25 kPa时,实际分选密度为1.666 g/cm^(3),可能偏差E值为0.09 g/cm^(3),重产物产率为75.23%。本研究为高含量重密度组分煤的分选提供了新的思路。

This study attempts to enhance the separation efficiency of dense media cyclone for raw coal feed with difficult-to-cleaning and large high-density component content.Specifically,this paper 1)designed a novel heavy media cyclone model device,2)established a mathematical model of sedimentation separation of particles in the centrifugal rotating flow field,3)investigated the separation characteristics of the new dense media cyclone by combining experimental research and theoretical analysis,which revealed the separation variation patterns of raw coal difficult to select with high content heavy density components under different process parameters,4)explored the factors affecting the dynamic stability of the working suspension in the flow field of the new heavy media cyclone and the discharge and transportation mechanism of heavy products.Results show that when the new dense media cyclone separates raw coal with high content of heavy density components,underflow heavy products exhibit stronger discharge capacity and higher processing capacity,while the centrifugal swirl field shows smaller density gradient distribution of suspension,more uniform density distribution,lower value of the difference between the underflow and the overflow density,as well as stronger stability of the suspension in the flow field.The feeding pressure is directly correlated with the dynamic stability of the suspension,separation accuracy and the discharge efficiency of heavy products.With increasing feeding pressure,the suspension discharged from the underflow and overflow port shows increased density difference,reduced possible deviation E value,improved separation accuracy and elevated amount of heavy product discharged.When the feeding pressure is 25 kPa,the actual separation density is 1.666 g/cm^(3),the possible deviation E value is 0.09 g/cm^(3),and the yield of heavy products is 75.23%,which provides new insights into the separation of raw coal with high content,heavy density components.