Disk centrifuge

Presented by :

Hasnain Ali

Roll no : 43

The outline

• General Idea• Purpose Of Centrifugation• Types Of Centrifuges• Properties Disk Stack Centrifugation• How It Works• Industrial Application And Uses• Design• Questions And Answers

of my presentation

General Idea

• Feed added to spinning bowl• Sedimentation of particles occurs in

centrifugal field• Flow is upwards at a particular rate

which determines residence time in device

• Separation happens if sedimentation velocity is high enough for particle to reach side of bowl within residence time

• Large particles have higher settling velocities than small particles

• Both large and small are still particles, have small Reynolds no.s (<1) and obey Stokes’ Law

• Centrifuge

Purpose Of The Centrifuge

• A key role in many industrial processes is to separate liquid phases and solids from each other

• Centrifugation can be utilized to separate the cellular from the released protein

The Centrifuge

• Separation of milk into skimmed milk and cream is done with a centrifuge

http://www.nzifst.org.nz/unitoperations/mechseparation4.htm

Types of centrifuge

1. Basket Used to separate solids from liquids, where a screen or

filtercan be used. (Cyclic type operation)

2. Decanter (Horizontal or Vertical Bowl)Used to separate solids from liquids. (Continuous type operation)

3. Vertical Disc

Used to separate solids from liquids and separate differentdensity liquids.

(Continuous type operation)

Types Of Centrifuges

decanter centrifuge

disk stack centrifuge

Basket centrifuge

Decanter Centrifuge - Two Main Types

Vertical

Horizontal

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1. Slurry enters into the center of the rotating screw conveyor and is discharged into the centrifuge through nozzles.

2. Centrifugal force causes the material to separate.

3. The conveyor moves the solids to the tapered end where they are thrown out.

4. Clear fluid flows out the other end.

A Common “Basket Centrifuge”

                     

                                   

ideal for a wide range of separation tasks that involve

particle size – 1.5 microns total solid percentage - 5.54-25%

proc

ess!

• lower solids concentrations

• smaller particle sizes

how a disk stack centrifuge works

• separates solids and liquid phases in a continuous process• uses extremely high centrifugal forces• denser solids are forced outwards against the solid bowl wall•inserting special plates provides additional surface settling area

Working Principleshow a disk stack centrifuge works

http://www.hutch-hayes.com/vertical_disc_applications.htm

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1. Liquid or slurry enters into the top of the centrifuge.

2. The higher density solids get pinned against the outer bowl wall.

3. The lowest density liquids are forced through the discs and back out through the top.

4. Higher density liquids are retained in the space between the discs and the solids and can be piped out.

A centrifuge of this type may also beknown as a clarifier, purifier, orconcentrator.

http://www.hutch-hayes.com/vertical_disc_applications.htm courtesy CONTEC 2004

Design of equipment

solid wallcontinuous liquids discharge

batch manual solids discharge

throughput

density difference

liquids viscosity

sedimentation area

disk diameter

height

speed

G

motor power

number of disks

134.4 L/min

1.05

0.89 cP

35 m2

0.33 m

0.16 m

5 500 rpm

10 400

6 hp

120

Keys To Exceptional Performancedesign considerations

efficiency depends on• solids volume fraction• sedimentation area• rotational speed

efficiency can be improved if • particle diameter is increased • residence time • distance for sedimentation

1. Dairy (Cream separators)

2. Food Processing (de-pulping of fruit juice, clarification of apple juice, wine clarification)

3. Marine (remove water from fuel / oil)

4. Offshore Oil (remove oil from water)

5. Environmental (remove oil from water)

6. Machine Tool (remove fine metallic particles from coolant)

• Food and Beverage

• processing and recovery of non-liquid food products

• processing of citrus fruit• wine and sugar processing• recycling of food-related products

Advantages• The most common advantages of centrifugal sedimentation,better

known as Centrifugal Separation are:

• compact size of equipment,• low capital investment,• versatility,• ease of use,• low operating costs,

• high performance.

Thank You! questions?