Mass transfer from the bulk of one phase to the interphase surface, and then from the interphase to the bulk of another phase, that is called Interphase mass transfer. There is no net transfer of the solute from one phase to other at equilibrium condition.

1. MASS TRANSFER
Presentation under the guidance of Mr. Yashwant Bhalerao

2. PREPARED BY :
Mr. HIMANSHU PRAJAPATI

3. • INTERPHASE MASS
TRANSFER
• EQUILIBRIUM BETWEEN THE
PHASES

4. INTERPHASE
MASS TRANSFER
MASS TRANSFER

5. Mass transfer from the bulk of one phase
to the interphase surface, and then from
the interphase to the bulk of another
phase, that is called Interphase mass
transfer.
INTERPHASE MASS TRANSFER

6. •
•
•
In absorption of solute gas A in a
liquid from a gas mixture,
Mass transfer occur in gas phase
from pA to pAi ( at the Interphase ).
And in the liquid phase from cAi ( at
the Interphase ) to cA.

7. In a sulphuric acid plant,
Example
H2SO4
H2SO4 + Moisture
• The air supplied to the sulphur burner
should be moisture-free.
• Drying of the air is done in contact with
concentrated sulphuric
acid in a 'packed
column.

8. • A packed column used for this purpose
consists of a cylindrical
shell filled with an
inert packing material
H2SO4 + Moisture
H2SO4
•
•
•
Moist air passed from the bottom.
And sulfuric acid sprayed from the top over the
packings.
An intimate contact between the two phases
occurs.

9. •
•
•
Moisture from the bulk of the air
diffuses to the air-H2SO4 interface.
gets absorbed in the liquid.
And then diffuses further into the bulk
of the liquid.
H2SO4
H2SO4 + Moisture

10. • the coke oven gas the majority of it contains the ammonia and it has
to be removed before it released to the atmosphere.
Example
Removal of ammonia from a byproduct
coke oven gas by water -
• so that the water selectively absorb ammonia and basically it
forms the ammonium hydroxide and the affinity of ammonia in
water is quite high.
• And, the best way to remove that component by contacting the
ammonia or contacting the product of the coke oven gas by water,

11. • The ammonia from gas mixture
diffuses to the gas liquid interface
• Get absorbed in water at the
interphase
• Transported into the bulk of water
How the process ocours ?

12. EQUILIBRIUM
BETWEEN THE
PHASES
MASS TRANSFER

13. •
•
•
Spontaneous alteration through molecular diffusion
occurs.
Ultimately brings the entire system to a state of
equilibrium, whereupon alterations stops.
There is no net transfer of the solute from one phase
to other.
EQUILIBRIUM BETWEEN THE PHASE

14. •
•
Equality of concentration of two phases does not
necessarily equilibrium.
At equilibrium : the chemical potential of the solute
among the phase are equal.

15. •
•
•
Consider, absorption of ammonia
from ammonia-air mixture by water in
a closed vessel.
The vessel contains some fixed
amount of water at constant
temperature and pressure.
An amount of ammonia-air mixture is
introduced in the vessel.
Example

16. •
•
Ammonia is soluble in water and
hence some amount of ammonia
will be transfered from gas to the
liquid.
Simultaneously, some ammonia
molecules will escape back into
the gas.

17. • The partial pressure of ammonia in gas phase and its
concentration in water will no longer change which is called
Equilibrium.
• The process of ammonia transfer continues
but not necessarily at the same rate.
• Eventually a times come when the
rate of transfer becomes equal

18. • When a system reaches to equilibrium state, can be
distributed if :
DISTURBANCE IN EQUILIBRIUM
1.
2.
3.
Temperature changes.
Pressure Changes.
Addition of small amounts
of species A or species B.

20. THANKS