Agitation and mixing

Agitation and Mixing are two important unit operations used in industries such as Impellers agitators are widely used to circulate the liquid through the vessel in which the dispersion of liquids and gases into other liquids like mixing of stiff paste, elastomers and dry solids powders takes place.

1. “ START WITH THE NAME OF ALLAH WHO
IS THE MOST BENEFICENT AND MOST
MERCIFUL.”

2. IHSAN ALI WASSAN
(14CH18)
DISCIPLINE:
CHEMICAL ENGINEERING

SUBJECT:
UNIT OPERATIONS-I
QUAID-E-AWAM UNIVERSITY OF ENGINEERING,
SCIENCE AND TECHNOLOGY NAWABSHAH, SINDH
PAKISTAN

3. AGITATION AND
MIXING

4. PRESENTATION OUTLINE
-Definitions
-Purposes of agitation
-Devices to produce agitation
-Conclusion

5. DEFINITIONS

6. AGITATION
 It refers to the induced motion of a
“homogenous” material in a specified way,
usually in circulatory pattern inside some sort
of container.

7. MIXING
Mixing the random distribution, into and
through one another, of two or more initially
separate phases.

8. PURPOSES OF AGITATION
 Suspending solid particles
 Blending miscible liquids
 Dispersing a gas through the liquid
 Dispersing a second liquid to form an emulsion
or suspension
 Promoting heat transfer

9. DEVICES TO PRODUCE
AGITATION

10. IMPELLERS
DEFINITION
The rotating part of a centrifugal pump,
compressor, or other machine designed to
move a fluid by rotation is called Impeller.
OR
A rotor used to increase (or decrease in case
of turbines) the pressure and flow of a fluid.
OR
A device turned by the flow of water past a
ship's hull, used to measure speed or distance
travelled.

11. IMPELLERS
Impeller agitators divided into two classes.

12. AXIAL-FLOW IMPELLERS
Those impellers that generate currents parallel
with the axis of the impeller shaft are called
Axial-Flow Impellers.
Axial-flow impeller

13. RADIAL-FLOW IMPELLERS
Those impellers that generate currents an a
radial or tangential direction are called radial
flow impellers.
Radial-flow
impellers

14. Three main types of impellers for low-to moderate
viscosity liquids are.
TYPES OF IMPELLERS

15. PROPELLERS
A propeller is an axial-flow, high speed
impeller for liquids of low viscosity.
Small propellers turn at full speed either 1,150
or 1,750 rpm.
Larger propellers turn at 400 to 800 rpm.

16. PROPELLERS (cont…..)
The ratio of distance to the propeller diameter
is known as pitch of the propeller.
A propeller with a pitch 1.0 is said to have
square pitch.
Propellers rarely exceeds 18 inch in diameter.

17. TURBINES
There are 4 types of turbine impeller
The straight-blade turbine
Disc turbine
Concave blade CD-6 disc turbine
Pitched-blade turbine

18. The straight-blade turbine
The simple pushes the liquid
radially and tangentially with
almost no vertical motion at
the impeller.
The current it generate
travel outward to the vessel
wall and then flow either
upward or downward.
Such impellers sometimes
called paddles.
straight-blade turbine

19. Disc turbine
The disc turbine with multiple straight blades
mounded on a horizontal disc.
Useful for dispersing a gas in a liquid.

20. Concave blade CD-6 disc
turbine
It is also used for
gas dispersion.
Consists of six
concave blades.

21. Pitched-blade turbine
Used when good
overall circulation
important.
Because it provides
some axial flow in
addition to the radial
flow.

22. HIGH EFFICENCY
IMPELLERS
The high efficiency impeller HE-3
has three slanted blades that are
crimped to decrease the blade
angle near the tip.
The A310 fluid foil impeller uses
air foil shaped blades with taper
so that they are narrower at the tip
than their edges.
Used to mix low-or moderate-
viscosity liquids.

23. CONCLUSION
In the whole it is concluded that during
agitation or mixing process “ Impellers
agitators are widely used to circulate the liquid
through the vessel in which the dispersion of
liquids and gases into other liquids like mixing
of stiff paste, elastomers and dry solids
powders takes place.”

24. Thank You
Everyone