给料压力对粗煤泥分级性能的影响

The influence of feed pressure on classification performance of coarse slime

水力旋流器作为粗煤泥入选前的主要分级设备,存在底流夹细、溢流跑粗的问题。以直径100 mm水力旋流器为研究对象,考察了压力变化对粗煤泥分级性能的影响;分析了粗煤泥分级过程中产品灰分变化规律,并从颗粒运移轨迹角度,进一步解释了不同性质粗煤泥分配行为差异。研究结果表明,粗煤泥在分级过程了发生了基于颗粒密度效应的分选行为,粗煤泥中不同密度不同灰分颗粒的存在会造成粗煤泥分级性能降低,通过增大给料压力可以在一定程度缓解颗粒密度对分级造成的不利影响。数值研究结果表明,不同粒度颗粒在水力旋流器内运移轨迹不同,低灰细泥沿内旋流从溢流口排出,部分高灰细泥受到较大的离心力作用,沿外旋流从沉砂口排出。研究结果可为粗煤泥高效分级提供理论指导。

As the main classification equipment before separation of coarse slime,the hydrocyclone has the problem of particle misplacement by overflow and underflow.A hydrocyclone with a diameter of 100 mm was used as the research object to investigate the influence of pressure changes on the classification performance of coarse slime.The ash content of the underflow product and overflow product were analyzed.The differences in the distribution behavior of coarse slime particles with different properties were further explained from the perspective of particle migration trajectory.The results showed that the coarse slime particles had a separation behavior based on the particle density during the classification process.The existence of particles with different density could reduce the classification performance of the coarse slime.By increasing the feed pressure,the adverse effects of particle density on classification could be alleviated to a certain extent.The numerical results showed that the migration path of different particle size in hydrocyclone was different.The low ash fine slime was discharged from the overflow along the inner vortex,while the high ash fine slime was discharged from the underflow along the outer vortex due to greater centrifugal force.The results can provide theoretical guidance for efficient classification of coarse coal slime.