Optimization Study On Overflow Structure Of Dual Vortex Finder Coal Slime Hydrocyclone Gravity Separation Column

To improve the confine of coarse slime hydrocyclone gravity separationcolumn producing just two products and productivity of clean coal, a concentricupper vortex finder was inserted into the gravity separation column, exchangingoriginal upward overflow plug to tangential overflow plug, a brand-new coalslime separation cyclone—dual vortex finder coarse slime hydrocyclone gravityseparation column came into being. The optimization study was conducted onfeeding pressure and structure parameter and the separation effect evaluationwas carried out. At last, CFD software Fluent was applied to simulate thedifferent upper vortex finder inradiums and depths, the results of simulationwere confirmed with that of tests.Coarse slime separation test was conducted under the different feedingpressure and the three products distribution rate and ash were calculated indifferent grades. The result showed that ash of overflow and side overflowdecreased firstly then increased with increasing of feeding pressure, theoverlarge feeding pressure would lead to over-grinding in coarse size in feedingmaterial. Coarse slime separation test was conducted under different depths ofouter vortex finder and the three products distribution rate and ash werecalculated in different grades. The result showed that increasing depth of outervortex finder would enhance ash of all three products, to ensure the ash of threeproducts, It was better keeping depth of outer vortex finder at190mm.Coarse slime separation test was conducted under the different depths andinradiums of upper vortex finder and the three products distribution rate and ashwere calculated in different grades. The results showed that ash of threeproducts increased mainly with the increasing of upper vortex finder depth andthe function of upper vortex finder transformed from fining to separating withfining. Changing inradium had a more obvious effect on separation thanchanging depth.Coarse slime separation test was conducted under the different sideoverflow structures and the three products distribution rate and ash werecalculated in different grades. The result showed that the decompression on sideoverflow plug would increase ash of three products and disqualified the upperoverflow product quality.The separation evaluation on three products was performed. The result wasthe following namely. Separation density of＞1mm was1.483g/cm3, E-p=0.1025, I=0.212; separation density of1-0.5mm was1.638g/cm3, Ep=0.222,I=0.348; separation density of0.5-0.25mm was1.852g/cm3, Ep=0.278, I=0.326.CFD was applied in the simulation on gravity separation column, simulation results showed that changing the inradium of upper vortex finder would affecteach velocities inside the field, especially on the tangential and axial velocitywhich were the critical reason on separation. The depth of upper vortex finderhad a more slight affection than inradium and its change regulation was notmonotonous. The phenomenon that axial velocity at L=65mm decreased slightlyproved the test result well.