Scribd
Upload
63 views18 pages

Centrifugation

Centrifugation is a process that uses centrifugal force to separate mixtures of solids and liquids. There are three main types: centrifugal sedimentation, filtration, and decantation. Centrifugal force is determined by rotational speed and radius. Common centrifuges include tubular, nozzle-discharge, disk, and basket centrifuges. The capacity of a centrifuge depends on factors like particle size, fluid densities and viscosities, centrifuge speed and geometry. Centrifugation is used for processes like settling, filtration, and washing.

Uploaded by

aaa
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
63 views18 pages

Centrifugation

Centrifugation is a process that uses centrifugal force to separate mixtures of solids and liquids. There are three main types: centrifugal sedimentation, filtration, and decantation. Centrifugal force is determined by rotational speed and radius. Common centrifuges include tubular, nozzle-discharge, disk, and basket centrifuges. The capacity of a centrifuge depends on factors like particle size, fluid densities and viscosities, centrifuge speed and geometry. Centrifugation is used for processes like settling, filtration, and washing.

Uploaded by

aaa
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 18

CENTRIFUGATION

Dr. Leonardo C. Medina Jr.

Perrys Chemical
Engineers Handbook
8th Edition

7th Edition

Section 18

Section 18

Pages 114 to 151

Pages 106 to 133

Centrifugation is a mechanical

process of separating multi-phase


mixture (usually fluid-solid system) via
the use of centrifugal force.
Centrifugal Sedimentation
Centrifugal Filtration
Centrifugal Decantation

CENTRIFUGAL
FORCE

,
,

Acceleration due to
ae r
centrifugal force,
where: r = radius,
2
mv
= angular velocity,
2

F
ma
mr
c
e
rad/s
r
Centrifugal Force,
60 60
2N
where v = linear

velocity
60
2
2r
In terms of the
2
2
2
rotation, N in
Fc mr v r 2N
rev/min, and

Fg mg rg g 60
Force ratio:
2

CLARIFYING CENTRIFUGE
Settling process (sedimentation) due to the
difference in densities of the solid and fluid
media. The most common type of equipment
used is a Sharples centrifuge.
Assuming STOKES LAW applies: Centrifugal force
balance on solid in the fluid media gives

r
2

ut
ut

2
p

18
2

18

D 2p

dr

dt

Tubular Centrifuge

Nozzle-Discharge Centrifuge

Disk Centrifuge

Particle Trajectory in
Centrifugal Sedimentation

integrating the above equation for a Sharples


centrifuge will give the capacity, qc given by

qc

18

2
pc

r2 r2
1
2
ln 2 r2
r1 r2

where qc is the capacity or the flow rate of


slurry such that particles larger than the
cut size D pc can be separated

If the thickness of the fluid in the


centrifuge is small, Ut is constant,
and the capacity becomes

qc

2b p
2

2 2
D pc r2

CENTRIFUGAL FILTRATION
For Filtration: P v mc a R

m
gc A

but

and

( r r )
2

2
2

2 gc

q
A

2
1

Top Suspended Basket


Centrifuge

Automatic Batch Centrifuge

Reciprocating Conveyor
Continuous Centrifuge

Centrifugal Filter

Therefore, the capacity of a centrifugal


filter becomes,

2
r2

m c
2
2
A

r1
Rm

A
2

If change in area with radius is large,

Where:

2
r2

r1

mc
Rm
2

A2
AL Aa
A a ri r2 b

AL 2b r2 ri / ln r2 / ri

A 2 2 r2 b

You might also like