Separator-Efficiency-Calculations.ppt
- 1. By Dr Y C Naidu
- 2. Types of classsification Basis of Volume ie geometric dimension- screening Basis of Mass ie materila properties Cyclone Separators Air Separators
- 3. Principles of Separation A particle is subjected to three sets of forces Fd-Force exerted by air Fc- Centrifugal force Fg- Force of gravity If Fd> Fc and Fg, particle air borne Fg prevails particle sink Fc prevails particle flung outward of separator
- 4. Particle Size Distribution Cumulative distribution curve On different sieves/micron sizes, the cumulative passing % is plotted. Independent particle size distribution curve
- 5. Size Distribution Curve 0 20 40 60 80 100 120 0 50 100 150 200 250 % passing Size, um Cumulative Size distribution
- 6. Particle Size Distribution 0 2 4 6 8 10 12 14 16 0 20 40 60 80 100 120 140 160 180 % of distribution Partcle Size, um Particle Size Distribution Curve Series1
- 7. Classification A= F+G A- Classifier feed rate, tph F-Fines output, tph G- Tailing output a,f,g- proportion of undersize in A,F,and G in % ∆a, ∆f, ∆g – Proportion of particular size fraction of A,F, G in %
- 8. Equations- Separators A.a = F.f+G.g A. ∆a = F. ∆f+G. ∆g Vf- % of output fines Vg- % of output tailings P- Precipitation efficiency µ- recycle ratio
- 9. Fines Output Vf =F/Ax100 Vg=G/Ax100 Vf+Vg =100
- 10. Calculated from particle size Vf= a-g x 100 f-g Vg = f-a x 100 f-g Recycle ratio = A/F = (f-g)/(a-g) Precipitation Efficiency = (Fxf)/(Axa)x100 = Vfxf/ax100
- 11. Selectivity It is characterized by what % of given particle size in classifier feed is discharged in tailings T – (Gxdg)/(A.da) x100 = Vg x dg/da
- 13. Cut Size Particle size dt of which half the particles are discharged in fines and half in tailings. If sharpness of separation poor, more than 50% of even finest particles may end up in tailings, so no definite cut size exists