unit operation , centrifugation

centrifugation ,Perforated-basket centrifuges�(centrifugal filters), Tubular-bowl centrifuge

2. Centrifugation is a process that involves the use of the centrifugal
force for the separation of mixtures

3. Principle of centrifugation Principle of centrifugation

5. If a particle (mass = m kg) spins in a centrifuge
(radius r, m) at a velocity (v, m s
-1
) then the centrifugal
force (F, N) acting on the particle equals m v
2
/r.
The same particle experiences gravitational force
(G, Newton) = m g (where g = acceleration due to gravity)
F = m v
2
/r
F= centrifugal force"g(xr!aTi!PrFgicvp
Centrifugal force (F)

6. isaprocethniooivanl u Centrifugal effect (C)
The centrifugal effect (C) is the ratio of these
two forces, so C = F/G, i.e. C indicates how much
greater F is than G
Centrifugal effect, C=
Force acting in radial direction
Gravitational force

7. Consider a body of mass ‘m” kg rotating in a circular path
of radius “r” at a velocity of “v”
Centrifugal force =f= mv
2
/r
Same body is experiencing gravitational force, it can be expressed
as “G= mg , where g = acceleration due to gravity, and m= mass
Centrifugal effect (C) = F/G
= mv
2
/mgr
(v = 2 π r n )
c = (2π r n)
2
/ g r
= 4 π
2
r

n
2
/ g
(d= r/2)
= 2 π
2
d n
2
/ g
(g = 9.807)
C = 2.013 d n
2

8. isaprocethniooivaln unfgmxPns
f
( Centrifugal effect, C= 2.013 n
2
d

9. =xlhhfcftlpfogaocatsgpefcdvsh Classification of centrifuges isasp rasp ocep trhnp ovlsup efp gsnoahfmxsp musPp oep
rgihs(spuslrarohenpenprnphnPmuoahr=pugr=sd
p
is aproceopthn vlhocpufglm p ieusp muhnxp lsafearosPp
TruFsoudp cihgip lsafeatp rp fh=oarohenovlsp elsarohenp
ceaFp=hFsprpulhnPavsaprnP
p xlPp(lhoeopthn vlhocpufgln mn ieusp choip rp ue=hPp
cr==sPp (suus=dp cisasp lraohg=sup usPhtsnop oecraPup
oispcr==pmnPsapoisphnf=msngspefpoispgsnoahfmxr=pfeags
There are two main types of centrifuge used to
achieve separation on an industrial scale,

(1)Filtration centrifuge: Those using perforated
baskets, which perform a filtration-type operation
(work like a spin-dryer) and
(2) Sedimentation centrifuge : Those with a solid
walled vessel, where particles sediment towards
the wall under the influence of the centrifugal force

10. t=dm=lutnlftuivthu=cd(Ttf
vthu=cd(TlFidcFut=f Perforated-basket centrifuges
(centrifugal filters)

11. Fig. Perforated basket centrifuge

13. isiaprosceathnvlrufignm
txhnvlrufigpatmnPu(nvlnrm= Tubular-bowl centrifuges
(centrifugal sedimenters)

14. Fig: Tubular-bowl centrifuge

16. isapsriroccetsahpnrvt Continuous centrifuge