This presentation based on the design of a LLE Equipment which is known as a KARR Extractor. It is a Mechanically agitated equipment.

1. 1

2. DESIGN OF KARR
EXTRACTOR
PRESENTED BY: GROUP # 04
WALEED SHAHID (UW-13-Ch.E-BSC-10)
MOHSIN RAZA (UW-13-Ch.E-BSC-18)
HASEEB IQBAL (UW-13-Ch.E-BSC-21)
SAEED (UW-13-Ch.E-BSC-23)
ALI HASSAN (UW-13-Ch.E-BSC-31)
M. FAHAD (UW-13-Ch.E-BSC-52) 2

3. MUHAMMAD FAHAD
(UW-13-CH.E-BSC-052)
3

4. DESIGN PROBLEM
The extractor is designed to separate a solution of methylene chloride and
methanol with the input mass flow rates of 2185 lb/h (991 kg/h) and 33 lb/h
(15.0 kg/h) respectively, using water as selective solvent with a mass flow rate
of 2218 lb/h (995 kg/h) to recover 95% methanol. Calculate the diameter and
height of the given system.
4

5. LIQUID-LIQUID EXTRACTION
Liquid-liquid extraction is a mass transfer operation in which a
solution (feed: mixture of solute and carrier liquid) is brought into
intimate contact with an immiscible or slightly miscible liquid
(selective solvent) in order to achieve transfer of the solute from the
feed to the solvent. The two liquid phases that have different
densities are then separated.
5

6. STEPS USED DURING LIQUID-LIQUID
EXTRACTION
• Bringing the feed and the solvent into intimate contact by
dispersing one phase into the other as droplets.
• Separation of the extract and the Raffinate phases that have
different densities.
• Removal and recovery of the solute from the extract phase in
relatively pure form (by evaporation, crystallization, etc.).
• Removal and recovery of the solvent from each phase, usually by
distillation. 6

7. LLE Vs. DISTILLATION
DISTILLATION LLE
Phase creation is achieved through Heat. No heat required.
Vapor and liquid are chemically similar. Phases are chemically different.
Used for liquids having large volatility difference.
Separation on the basis of boiling point.
Used for liquids having low or negligible volatility
difference.
It is an expensive method of separation. Relatively cheaper.
7

8. M.WALEED SHAHID
(UW-13-CH.E-BSC-010)
8

9. ADVANTAGES AND DISADVANTAGES
ADVANTAGES DISADVANTAGES
Liquid-liquid extraction can be used in the
separation of azeotropes.
Can be time consuming, especially if attainment of
equilibrium is slow
It can be operated at low to moderate temperature
for recovery of heat sensitive products
Can be affected by small impurities in the
solvent(s).
LLE is cheaper and can be used instead of using
the chemical methods.
Cumbersome for a large number of samples or for
large samples.
It has rapid and very selective separations that are
usually highly efficient.
Formation of emulsions can interfere with the
phase-separation process
Also used for components that have close boiling
points
Counter-current process can be complicated and
can require complicated equipment
9

10. APPLICATIONS
• Extraction of Fermentation Broth by using Karr Reciprocating-Plate Extractor.
• Extraction of Penicillin in Karr Reciprocating-Plate Extractor.
• Use of Ionic Liquid in a Karr Reciprocating-Plate Extractor.
• Recovery of tightly hydrogen-bonded organics from water; such as formaldehyde,
formic acid and acetic acid.
• Removal of high boiling organics from wastewater; such as phenol, aniline and
nitrated aromatics
• Essential oil extraction; such as pharmaceuticals, flavors, fragrances and food
products.
• Such as acrylates, nitrated organics and chloro-benzene compounds.
10

11. LIQUID-LIQUID EXTRACTION
EQUIPMENT
The equipment used to carry out the LLE are called Liquid-Liquid Extractors.
Common extractors are divided into following classes:
11
FLUID MOVEMENT MECHANICALLY AGITATED
Sieve column KARR column
Packed column SCHEIBEL Column
Spray column Pulsed column
Mixer settler Rotating disk contractor

12. ALI HASSAN
(UW-13-CH.E-BSC-031)
12

13. SIMPLE GUIDLINE FOR EXTRACTOR
SELECTION
Process
Minimum residence time
Emulsifying tendency
Flow rate over 400 gal/min , minimum residence
Small number of stages required
No
No
No
No
Centrifugal contractor
Reciprocating plate column , centrifugal
contractor
Mixer settler
Mixer settler (with out mechanical agitation)
Mechanically agitated column
Yes
Yes
Yes
Yes
13

14. SELECTION OF EQUIPMENT
We selected Karr Reciprocating-Plate Column for the given system, because it
is suitable for the systems having intermediate to low interfacial tension and
emulsifying tendency.
14

15. KARR RECIPROCATING-PLATE
COLUMN
The Karr Reciprocating-Plate column is a descendent of the pulsed sieve-tray
column. It has a reciprocating shaft with perforated plates mounted on it. In
this column plates move up and down approximately 2–7 times per second.
Also, the close spacing of the plates (25–50 mm) promotes high turbulence and
minimizes axial mixing, thus giving high mass-transfer rates and low HETS.
The central shaft, which supports sets of plates, is reciprocated by a drive at the
top of the column.
15

16. KARR EXTRACTOR
16

17. WORKING OF KARR EXTRACTOR
17

18. SAEED AKHTAR
(UW-13-CH.E-BSC-023)
18

19. CASE
The extractor is designed to separate a solution of methylene chloride and
methanol with the input mass flow rates of 2185 lb/h (991 kg/h) and 33 lb/h
(15.0 kg/h) respectively, using water as selective solvent with a mass flow rate
of 2218 lb/h (995 kg/h) to recover 95% methanol. Calculate the diameter and
height of the given system.
19

20. GIVEN DATA
Feed:
• Methylene chloride = 2185 lb/hr
• Methanol = 33 lb/hr
• Total = mF =2218 lb/hr
• Recovery coefficient = K = 2
• Methanol recovery % = =0.95
• Concentration mass unit= C = 0.5

20

21. CONTINUED...
Densities:
• Methylene chloride =82.41
• Methanol = 48.7
• Water =62.4
• x1 = mass fraction = 33/2218 = 0.0148
.
3
lb ft
3
lb ft
3
lb ft
21

22. DESIGNING STEPS FOR THE KARR
EXTRACTOR
Step 1: Mass Fraction in Raffinate
Step 2: Minimum Solvent Flow Rate
Step 3: Minimum Solvent Rate and Operating Rate
Step 4: Mass Fraction of Solute in Extract
Step 5: Calculation of Extraction Factor AE
Step 6: Calculate the Number of Equilibrium Stages
Step 7: Extractor Diameter
22

23. SOLUTION
Step 1: Mass Fraction in Raffinate
For Finding the mass fraction in Raffinate we use following equation.
2 1x = ( 1- ε ) x
2x 0.000744
23

24. CONTINUED...
Step 2: Minimum Solvent Flow Rate
F 1 2
SM 1 2
m Kx - y
=
m (x - x )
2(0.01488)-0
= = 2.105
(0.01488-0.000744)
24

25. CONTINUED...
Step 3: Minimum Solvent Rate and Operating Rate
F F
S SM
m m
= C
m m
 
 
 
=0.5×2.105
F
S
m
= 1.053
m
Fm = 2218 lb hr
s
2218
m = = 2106 lb hr
1.063
,
F
SM
m
= 2.105
m
25

26. CONTINUED...
Step 4: Mass Fraction of Solute in Extract
 F
1 2 1 2
S
m
y = y + x -x
m
 
 
 
=0+(1.053)(0.01488-0.00074)
1 0.014885y 
26

27. CONTINUED...
Step 5: Calculation of Extraction Factor AE
 F S
E
m /m
A =
K
E
1.063
=
2
A = 0.5265
27

28. Step 6: Calculate the Number of Equilibrium Stages
CONTINUED...
 
 
   1 2
E E E E
2 2
x - y K
N = log 1-A + A log (1 A )
x - y K
 
 
 
   E
0.014878-0
N =log 1-0.5265 +0.5265 log(1 0.5265)
0.000744
 
  
EN =3.587
EN 4
28

29. HASEEB IQBAL
(UW-13-CH.E-BSC-021)
DESIGN OF KARR EXTRACTOR 29

30. CONTINUED…
• Step 7: Extractor Diameter and Height
For calculation of extractor Height we require HETS
As
For HETS calculation, we require Diameter of extractor.
As
 E EZ =N HETS
 
0.38
1
1
D
HETS= HETS
D
 
 
 
30

31. 31

32. CONTINUED…
• Now we have to calculate Diameter of our system for which we calculate
area, which is
 
1
1
2
D = 12 inches
Min HETS = 5.6
Volumetric Throughput = 1193 gal h.ft
SF F Sm ρ +m ρ
A =
J
32

33. CONTINUED…
Volumetric Flow Rates of both Feed and Selective solvent.
Feed =
Selective Solvent
Area Volumetric Throughput
3F
F
m 2185 33
= + = 27.19 ft hr
ρ 82.41 48.7
3S
S
m 2106
= = = 33.7514 ft hr = 252.4942 gal hr
ρ 62.43
SF F Sm ρ +m ρ
=
J
2203.418+262.4942
= = 0.3812 ft
1193
2
gal
J= 1193
hr.ft
33

34. CONTINUED…
So for our system
Diameter
So this calculated Diameter is less than 30 inch and we have standard pipe size of diameter
10.42 inch, so we use 10.42 inch pipe.
HETS
0.5 0.5
A 0.38067
= 4× = 4× = 0.6975ft
π 3.14
   
      
0.38 0.38
1
1
D 10.42
=(HETS) =5.6 =5.307in
D 12
   
     
34

35. CONTINUED…
For our design we increase value of HETS by 20% to avoid flooding.
Rounding off ZE to nearest 3
On both top and bottom we have installed settlers which have the diameter 50% greater than
the extractor diameter and also height of each settler is equal to settler diameter.
E E
Corrected HETS=5.307×1.20=6.368 in
Z =N (HETS)=4(6.368)=25.47
EZ =27
35

36. CONTINUED…
Diameter of settler =
Height of both settler =
To join Extractor with settler we require reducers which are a foot long.
Now reduces height =
1.5×10.42=15.63 inch
2×15.63=31.26 inch
2 12 24 
E SZ=Z +Z +Reducers height
=27+31.26+24=82.26inch
Z=6.86ft
36

37. CONTINUED…
Approximated height is:
Z=7ft
37

38. MOHSIN RAZA
(UW-13-CH.E-BSC-018)
38

39. EFFECT OF CONCENTRATION ON
HEIGHT
7
8 8
10
12
5
6
7
8
9
10
11
12
13
0.4 0.5 0.6 0.7 0.8 0.9 1
Height(ft)
Concentration (lb/ft3)
39

40. EFFECT OF RECOVERY % ON
HEIGHT
40
6.772
6.272
5.6885.6885.688
5.1885.1885.1885.1885.188
5
5.5
6
6.5
7
0 10 20 30 40 50 60 70 80 90 100
Height(ft)
Recovery (%)

41. EFFECT OF CONCENTRATION ON
HEIGHT
41
8.4 8.5
8.8
9
9.2
9.4
9.7
9.9
10.1
10.3
10.5
10.7
10.9 11
11.2
11.4
11.6
11.8
12 12.12
8
8.5
9
9.5
10
10.5
11
11.5
12
12.5
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Diameter(in)
Solvent Rate in Feed (lb/hr)

42. 42

43. 43