describing working, principle and construction of rotary drum filter, disk centrifuge, microfiltration

1. PRESENTED BY : HIMANSHU KHADATKAR
TOPICS COVERED :
• 1. ROTARY DRUM FILTER
• 2. MICRO FILTRATION (CROSS FLOW FILTRATION)
• 3. DISK CENTRIFUGE

2. ROTARY DRUM FILTER
CONSTRUCTION
• It consists of a sheet metal drum. The diameter of drum ranges from 1 to 10
feet.
• A vacuum system is also attached, so that during filtration whole drum work
under vacuum.
• The surface of drum is divide into different section by stripes:
• Cake formation area
• Washing zone
• Drying zone
• Cake removal zone
• Filter medium is hold by metal stripes on drum am covered by filter cloth.
• In each section there are many pipes which open inside the cover paltes.
• After washing, cake is removed using any cake removal techniques.

3. ROTARY DRUM FILTER
CONSTRUCTION

4. ROTARY DRUM FILTER
Construction

5. ROTARY DRUM FILTER
PRINCIPLE
• It is a application of vacuum filtration.
• In operation, the drum rotates slowly about the horizontal axis and is partially
submerged in a slurry reservoir, so that each unit passes through the various
zones.
• The surface of the drum is covered with the filter medium
and a vacuum is maintained below the medium on the side
of the drum.
• Liquid is sucked through the filter medium and solids are
retained on the medium.
• Filtration is followed by cake washing and dewatering.

6. ROTARY DRUM FILTER
WORKING

7. ROTARY DRUM FILTER
WORKING
• Before filtration rotary drum is dip in tank of filter aid for precoating(perlite or
diatomaceous.)
• Drum is rotated in slurry tank at the speed of 1 to 2 rpm. 1/3 th of drum is
dipped
in the slurry tank and vacuum is applied.
• Cake formation takes place as drum rotates.
• As the panel leaves the cake formation area, it enters the washing area where it
is hydrated again.
• From the washing area the panel moves to the drying area and then cake is
removed in the cake removal zone.

8. MICRO FILTRATION (CROSS FLOW FILTRATION)
PRINCIPLE
• Microfiltration is a membrane solid separation technique that can be used to
remove particles and suspended solids from colloidal solutions or suspension.
• Two distinct configurations are commonly employed for microfiltration are cross
flow microfiltration and dead end microfiltration.
• Particle size in the range of 0.05-10 microns.
• Microfiltration is suited to separate larger sizes such as suspended solids,
particulates, and microorganisms.
• In cross flow microfiltration the suspension flows with speed tangential to the
direction of the membrane.
• With cross flow filtration a constant turbulent flow along the membrane surface
prevents accumulation of matter on the membrane surface.

9. MICRO FILTRATION (CROSS FLOW FILTRATION)
PRINCIPLE
• Clear liquid permeates the filtration medium and is recovered as permeate, while
the solids accumulate at the filtration barrier to form a cake.

10. MICRO FILTRATION (CROSS FLOW FILTRATION)
CONSTRUCTION

11. MICRO FILTRATION (CROSS FLOW FILTRATION)
WORKING
• Raw water enters tank for feed to the membranes.
• A level control gauge in the tank modifies inlet valve operation such that the
tank maintains a constant level.
• Pump moves the raw water to the membranes. This pump is controlled by a
variable frequency drive to adjust the output based on the flow rate requested
by the operator.
• Feed to the membrane passes through a basket strainer to remove any larger
solids that might otherwise clog the fiber inlet ends.
• Permeate flows directly to an existing storage tank, while reject flows back to
initial tank.
• No water is lost during normal operation.

12. MICRO FILTRATION (CROSS FLOW FILTRATION)
WORKING

13. DISK CENTRIFUGE
CONSTRUCTION

14. DISK CENTRIFUGE
CONSTRUCTION
• A short, wide bowl 200 to 500 mm (8 to 20 in.) in diameter turns on a vertical
axis.
• Feed enters from above through a stationary pipe set into the neck of the bowl.
• Inside the bowl and rotating with it are closely spaced "disks," which are actually
cones of sheet metal set one above the other
• Matching holes in the disks about halfway between the axis and the wall of the
bowl form channels through which the liquids pass.
• There are many types of disc centrifuge; the principal
difference between them is the method used to discharge
the accumulated solids.

15. DISK CENTRIFUGE
PRINCIPLE
• Disc stack separators are ideal for a wide range of separation tasks that involve
lower solids concentrations and smaller particle and droplet sizes. This applies to
both liquid–liquid and liquid–solid separation.
• The basic centrifuge idea is based on what
happens in a settling tank, in which particles,
sediment and solids gradually fall to the bottom,
and the liquid phases of different density separate
due to the force of centrifugal force.

16. DISK CENTRIFUGE
WORKING
• A disc stack separator separates solids and one or two liquid phases from each
other in one single continuous process, using extremely high centrifugal forces.
• The feed enters the actual compartment at the bottom and travels upwards
through vertical spaced between the disks.
• The holes divide the vertical assembly into an inner section, where mostly light
liquid is present, and an outer section, where mainly heavy liquid is present. The
heavy liquid flows beneath the underside to the periphery of the bowl without
encountering any more light liquid.
• Light liquid similarly flows inward and upward over the upper
surfaces of the disks.

17. DISK CENTRIFUGE
WORKING
• Any small amount of heavy solids is thrown at the
outer wall.
• In simple disc centrifuges, solids must be
removed periodically by hand
• Disk centrifuges are particularly valuable where
the purpose of the centrifuging is not complete
separation but the concentration of one fluid
phase, as in the separation of cream from milk
and the concentration of rubber latex.(Because of
the difficulty in removal of solids)

18. REFERENCES
• https://en.wikipedia.org/wiki/Rotary_vacuum-drum_filter
• http://www.porexfiltration.com/learning-
center/technology/what-is-cross-flow-filtration/
• https://www.mdpi.com/2077-0375/9/11/146/htm
• https://www.sciencedirect.com/topics/engineering/disk-
stack
BOOK REFERED
• McCabe W. L., Jullian Smith C. and Peter Harriott - Unit
Operations of Chemical Engineering, 7 thEdition, McGraw-
Hill international Edition, 2005.

19. THANK YOU