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