LIQUID-LIQUID EXTRACTION MODELS/APPLICATIONS
LIQUID-LIQUID EXTRACTION
MODELS/APPLICATIONS
EQUILIBRIUM RELATIONSHIPS
• PHASE RULE FOR LLE
• VARIABLES INCLUDED– PRESSURE– TEMPERATURE– 4 COMPOSITIONS (2 IN EACH PHASE)
3223
23
2
PHASESCOMPONENTSFOR
PC
/
LLE DIAGRAMS - FORMS
• LLE CAN BE PRESENTED IN VARIOUS FORMATS– TRIANGULAR, CARTESIAN,
McCABE-THIELE
Cehreli, S.; Bilgin, M, .Quaternary Liquid-Liquid Equilibrium of Water + Acetic Acid + Propionic Acid + Solvent (Amyl Alcohol, Cyclohexyl Acetate, or Toluene) Systems, J. Chem. Eng. Data; (Article); 2004; 49(5); 1456-1459.
OTHER LLE PLOTS
Kim, J.-K.; Park, D.-W., Liquid-Liquid Equilibrium for the Quaternary System Toluene + Water + Propionic Acid + Ethyl Acetate at 25 C and Atmospheric Pressure , J. Chem. Eng. Data; (Article); 2005; 50(2); 625-629
LLE PLOTS
Kim, J.-K.; Park, D.-W., Liquid-Liquid Equilibrium for the Quaternary System Toluene + Water + Propionic Acid + Ethyl Acetate at 25 C and Atmospheric Pressure , J. Chem. Eng. Data; (Article); 2005; 50(2); 625-629
LLE PLOTS• CARTESIAN SOLVENT-FREE PLOT
PERRY’S Ed. 7, PAGE 15-7
SINGLE STAGE LLX MODELS
• MASS BALANCES INCLUDE OVERALL AND COMPONENT
• NEED EQUILIBRIUM DATA TO CALCULATE EQUILIBRIUM CHANGES
• STAGE EFFICIENCY LESS THAN 100% RESULTS IN A CHANGE IN RELATIVE LOCATION OF xa VS xa* EMPLOYS LEVER RULE
SINGLE STAGE LLX MODELS• TYPICAL MODEL FOR PROCESS:
Pandit, P.; Basu, S., Dye and Solvent Recovery in Solvent Extraction Using Reverse Micelles for the Removal of Ionic Dyes , Ind. Eng. Chem. Res.; (Article); 2004; 43(24); 7861-7864.
MULTIPLE STAGE LLX MODELS
• MODEL USES OVERALL AND COMPONENT MASS BALANCES
• EQUILIBRIUM DATA USED INITIALLY TO DETERMINE MINIMUM SOLVENT (L/V) RATIO (PONCHON-SAVARITT)– LOCATES ya,min ON EXTENDED EQUILIBRIUM TIE
LINE PASSING THROUGH xa
– USE LEVER RULE TO DETERMINE Vb,min
• LOCALIZED EQUILIBRIUM VALUES CAN RESULT IN ACTUAL Vb,min VALUES BEING HIGHER AND THIS WILL BE NOTICED IN ACTUAL DESIGN IF Ncalc = ∞
MULTIPLE STAGE LLX MODELS
• SEQUENTIAL FEED – NORMALLY COUNTERCURRENT
Nishihama, S.; Hirai, T.; Komasawa, I., Separation and Recovery of Gallium and Indium from Simulated Zinc Refinery Residue by Liquid-Liquid Extraction , Ind. Eng. Chem. Res.; (Article); 1999; 38(3); 1032-1039.
MULTIPLE STAGE LLX MODELS
• DESIGN IS BASED ON RATIO OF Vb,act TO Vb,min
• USED TO LOCATE ya,act
• DESIGN POINT BASED IN INTERSECTION OF xa-ya LINE WITH xb-yb LINE.
• STAGES ARE STEPPED OFF BY ALTERNATING BETWEEN INTERSECTIONS ON EQUILIBRIUM ENVELOPE DEFINED BY EQUILIBRIUM TIE LINES AND LINES FROM DESIGN POINT.
MULTIPLE STAGE LLX MODELS
• McCABE THEILE DIAGRAM CAN BE CONSTRUCTED FROM DATA FROM PONCHON-SAVARITT
• ALTERNATELY, IF B & S ARE RELATIVELY IMMISCIBLE AND FLOWS ARE SPECIFIED, THEN INERT FLOW MODEL CAN BE USED FOR THE OPERATING LINE. USING COMPONENT BALANCES FOR SOLUTE, A:
MULTIPLE STAGE LLX MODELS• INERT FLOWS MODEL
• L' = NON-TRANSFERRING B IN RAFFINATE AND V' = NON-TRANSFERRING S IN EXTRACT.
• CAN BE PLOTTED WITH EQUILIBRIUM LINE ON McCABE-THIELE FOR CALCULATIONS
a
a
n
n
n
n
a
a
a
a
b
b
b
b
a
a
y
yV
x
xL
y
yV
x
xL
STAGEINTERIMFOR
y
yV
x
xL
y
yV
x
xL
OVERALL
1111
1111
1
1 ````
````
LLX EQUIPMENT• MIXER-SETTLERS
A + B S
EXTRACT LAYER
RAFFINATE LAYER
EXTRACT
FAFFINATE
MIXER SETTLER
LLX EQUIPMENT
• SPRAY TYPE EXTRACTION TOWER
Chen, Liang-Huei (Chia-Nan Coll of Pharmacy and Science); Lee, Yuh-Lang, Effects of a surfactant on the mass transfer in spray-tower extraction column, Chemical Engineering Journal, v 73, n 1, 1999, p 77-81
SPRAY TYPE EXTRACTION TOWER
• USES A SPARGER FOR LIGHT LIQUID AND DISPERSER FOR HEAVY LIQUID
• OVERFLOW IS LIGHT/UNDERFLOW IS HEAVY
SIEVE TRAY EXTRACTION TOWER
• SIMILAR TO DISTILLATION UNIT
J. Antonio Rocha, J. Carlos Cardenas, Cesar Sosa, and Jorge Rosales, Preliminary design of sieve tray extraction columns. 1. Determination of the column diameter. Flooding velocities in sieve tray extractors , Ind. Eng. Chem. Res.; 1989; 28(12) pp 1873 - 1878
SIEVE TRAY EXTRACTION TOWER
• LIGHT LIQUID INVENTORIED UNDER EACH TRAY
• BUBBLES OF LIGHT LIQUID PASS THROUGH COUNTERFLOW OF HEAVY LIQUID
• DOWNCOMERS ARE USED TO TRANSFER HEAVY LIQUID DOWN THE COLUMN
SIEVE TRAY EXTRACTION TOWER
• DOWNCOMER DESIGN
J. Antonio Rocha, J. Carlos Cardenas, Cesar Sosa, and Jorge Rosales, Preliminary
design of sieve tray extraction columns. 1. Determination of the
column diameter. Flooding velocities in sieve tray extractors
, Ind. Eng. Chem. Res.; 1989; 28(12) pp 1873 - 1878
YORK-SHEIBEL COLUMN• YORK-SHEIBEL COLUMNUSES AGITATION TO
MIX MATERIAL FOR EACH STAGE WITH SETTLING OCCURING OUTSIDE THE AGITATION ZONE
PODBEILNIAK CENTRIFUGAL
• PROVIDES A SINGLE STAGE HIGH g CONTACTING
LIGHT OUTLIGHT IN HEAVY INHEAVY OUT
CONTACTINGREGIME
PROCESSES THAT UTILIZE LLX • TYPICALLY ARE THOSE IN WHICH DISTILLATION IS
NOT ECONOMICALLY ATTRACTIVE• SULFOLANE PROCESS (UOP) -RECOVERY OF
AROMATICS, COMBINES DISTILLATION WITH LLE
http://www.uop.com/
objects/55%20Sulfolan
e.pdf
PROCESSES THAT UTILIZE LLX
• BIOTECH AND BIOPHARM– SEPARATION OF HIGH MOLECULAR
WEIGHT FATTY ACIDS FROM VEGETABLE OILS
– PENICILLIN
Alfred Thomas, Fats and Fatty Oils, Ullmann's Encyclopedia of Industrial ChemistryCopyright © 2002 by Wiley-VCH Verlag GmbH & Co. KGaA
PENICILLIN PRODUCTION
PROCESS
Joseph A. Shaeiwitz, Joseph D. Henry, Jr.,
Biochemical Separations ,Ullmann's Encyclopedia of
Industrial ChemistryCopyright © 2002 by
Wiley-VCH Verlag GmbH & Co. KGaA
SUPERCRITICAL EXTRACTION
• SOLVENT IS AT SUPERCRITICAL CONDITIONS
• SUPERCRITICAL SOLVENT HAS THERMODYNAMIC AND TRANSPORT PROPERTIES THAT ARE SIMILAR TO A LOOSE LIQUID OR A DENSE GAS.– SOLUTE EXTRACTION BASED ON SOLUBILITY IN
SUPERCRITICAL PHASE– PRODUCT IS OBTAINED BY LETTING PRESSURE DOWN
TO SUBCRITICAL CONDITIONS• PROCESS DESCRIBED IN TEXT DECAFFINATION IS
MORE LIKE SUPERCRITICAL LEACHING
TYPICAL SC PROCESS
• Eldridge, R. B., Oil Contaminant Removal from Drill Cuttings by Supercritical Extraction, Ind. Eng. Chem. Res.; (Article); 1996; 35(6); 1901-1905.