Solvent Cycle, Methods for Solute Precipitation
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Solvent Cycle, Methods for Solute Precipitation Heat and Mass Transfer: High Pressure chemical Engineering I (WS) Chapter 7
description
Chapter 7. Solvent Cycle, Methods for Solute Precipitation. Heat and Mass Transfer: High Pressure chemical Engineering I (WS). Flow Scheme of a Solvent Cycle. Solvent Cycle. Solvent Cycle Steps: separate the extract from the solvent (1), clean the solvent for reuse (2), - PowerPoint PPT Presentation
Transcript of Solvent Cycle, Methods for Solute Precipitation
Solvent Cycle,
Methods for Solute Precipitation
Heat and Mass Transfer:
High Pressure chemical Engineering I (WS)
Chapter 7
Flow Scheme of a Solvent Cycle
Solvent Cycle Steps:
separate the extract from the solvent (1),
clean the solvent for reuse (2),
remove the solvent from raffinate (3),
adjust composition of solvent mixture (if applicable) (4).
Solvent Cycle
Single stage Multiple stage Counter- Chromato- (precipitation) current graphic
SFE Modes of Operation
Extraction From Solids S t S / F
Essential oils (5 %) 20 < 1 > 20
Edible oils (2 %) 40 < 1 40
Coffee decaffeination (0.01 %) 200 5 40
Black tea decaff. (0.01 %) 230 1.5 150
Total amount of solvent S, kg/kgF
Extraction time t, h
Solvent to Feed Ratio S/F, kgS /(kgF h)
Basis:
Solvent: Carbon dioxide
10 - 30 MPa, 330 K
Solvent Cycle: Solvent to feed ratio of SFE processes
Countercurrent Separation V/L v S / F
FAEE, FAME (5 %) 20 7.5 125
FFA (fatty acids) (2 %) 50 4.5 50
Squalene (1.5 %) 20 10 50
Tocopherol-Purif. (2.5 %) 35 20 45Solvent ratio V/L, kg/kg
Reflux ratio v, -
Solvent to feed ratio S/F, kgF /kgF
Basis:
Solvent: Carbon dioxide
10 - 30 MPa, 350 K
Solvent Cycle: Solvent to feed ratio of SFE processes
Chromatographic Separation
Pr tr S / F
DHA / DPA 1.5 15 900 x 103 EM
Phytol-isomers 10- 30 6 900 EM 200 SMB
Productivity Pr, gP /(kgStPh h)
Retention time, min
Solvent to feed ratio S/F, kgF /kgF
Basis:
Solvent: Carbon dioxide
10 - 30 MPa, 310 K
Solvent Cycle: Solvent to feed ratio of SFE processes
Reduction of pressure or density
Anti solvent
Membrane separation
Adsorption
Absorption
De-Entrainment
......
Modes For Product Recovery
300 400 500 600 700 800 90010
100
1000
T = 313 K T = 318 K T = 333 KSo
lubi
lity
[mg/
kg C
O2]
Density [kg/m3]Birtigh, Brunner, Johannsen
Solubility of Caffeine in CO2
Gas Circuit in the Compressor Mode
Compressor Process, Throttling Sub-Critical
Compressor Process, Throttling Super- Critical
Pump Process
Pump Process, Throttling, Sub-Critical
Pump Process, Throttling Super- Critical
Extraction temperature: 313 K
Energy Consumption by Various Solvent Cycles
Mechanical EnergyThermal energy inThermal energy out
Pump with heat recovery
Pump without heat recovery
Compressor with heat recovery
Compressor without heat recoveryEx
trac
tion
pres
sure
[MPa
]
Energy [kJ/kg]
Energy needed for the gas cycle
70 kJ/kgCO2
95 kJ/kgCO2
for S/F 125 kg/kg:
8750 kJ/kgFeed
11875 kJ/kgFeed
Reduction of pressure or density (temperature)
Anti solvent
Membrane separation
Adsorption
Absorption
De-Entrainment
Modes For Product Recovery
Brunner 1983
Solubility in a Gas With a Modifier (Entrainer)
Influence of temperature
Data by:Gährs 1984Ebeling, Franck 1984Johannsen, Brunner 1994
Solubility of Caffeine in CO2
Reduction of pressure or density
Anti solvent
Membrane separation
Adsorption
Absorption
De-Entrainment
......
Modes For Product Recovery
Gährs 1984
Anti-Solvent: Solubility of Caffeine in CO2
Influence of nitrogen
Reduction of pressure or density
Anti solvent
Membrane separation
Adsorption
Absorption
De-Entrainment
......
Modes For Product Recovery
PC
WT2
1
PC
P1
B1RV3
PC
WT1 K1
RV1
RV2
M1
18 MPa323 K
P = 2 MPa
Coupling with a Membrane UnitSolvent Cycle With Membrane Separation
GKSS-membrane (organic, active dense layer)
CO2
OC
Permeate
Retentate
1.86 wt.-%
< 0.06 wt.-%
p = 2.0 MPa
active dense layer
1.5 mole CO2
kg/(m2 h)
P = 18 MPa, T = 323 K
Separation by Membranes
Solvent Cycle in a T,s - Diagram
Extraction/separation
Precipitation athigh p
Precipitation atlow p
Compressor mode
Entropy
Tem
pera
ture
CO 2
53 kJ/ kgCO2
21 kJ/ kgCO2
7.6 kJ/ kgCO2
1
2
3
Wie in 2Like in 2
Energy For Different Solvent Cycles
Pump-Cycle
Compressor-Cycle
Membrane-Cycle
Sartorelli 2001
Reduction of pressure or density
Anti solvent
Membrane separation
Adsorption
Absorption
De-Entrainment
......
Modes For Product Recovery
0 100 200 300 400 500 600 700 800Y [mg/kg CO 2]
0
0.1
0.2
0.3
0.4
0.5X
[kg
/kg
AC
]
T=318 KP=13 MPaP=20 MPaP=30 MPaP=13 MPa LangmuirP=20 MPa LangmuirP=30 MPa Langmuir
Adsorption of Caffeine on Activated Carbon
Silica with 52% loading,loaded by high pressure
adsorption
Silica with 50% loading, loaded by mixing,
conventional process
Recovery of Tocopherolacetate by Adsorption
200 250 300 350 400 450 500 550 600
40
45
50
55
60
autoclave: 333K, 20MPafixed bed adsorber: 353Kflow: 20gsolvent/min
feed in autoclave: TA ca. 97 wt.-% TA ca. 73 wt.-%
Load
ing
of a
dsor
bate
[wt.-
%]
Density CO2 [kg/m3]
Recovery of Tocopherolacetate by Adsorption
Reduction of pressure or density
Anti solvent
Membrane separation
Adsorption
Absorption
De-Entrainment
......
Modes For Product Recovery
100 1000 10000
10
100
1000 P = 19 MPa
T = 343,1 K T = 323,1 K
P = 28 MPa T = 343,1 K
Caffe
ine
Load
ing
inSC
F Ph
ase
[mg/
kg]
Caffeine Loading in Water Phase [mg/kg]
Phase Equilibrium Caffeine - Water - CO2
Reduction of pressure or density
Anti solvent
Membrane separation
Adsorption
Absorption
De-Entrainment
......
Modes For Product Recovery
Brunner 1983
Solubility in a Gas With a Modifier (Entrainer)
Influence of temperature
0 0.05 0.1 0.15 0.2 0.25 0.3
mwater / mtotal
00.10.20.30.40.50.60.70.8
toco
chro
man
ol fr
actio
n
in fl
uid
phas
e [m
ass%
]
solubility tocochromanol in CO2
Figure 4:Tocochromanol fraction in SCF phase as function of the total water fraction
Birtigh
De-Entrainment
Generalization of Precipitation: Membership - Functions
Temperature at the Swimming Pool
T [oC] x25 35 450
1
(x)
„Hot“Not yet hot Too hot
(x): relative number of statements from people at the pool
0 1 2
0.1 0.5 0.9 0.2 0.9 1.6
1 4 7
Molar weight solute [kg/mol]
Loading
Reduced Pressure
Residence time [min]
fluid phase [wt%]
0.0
0.5
1.0
0.0
0.5
1.0
0 1 20.0
0.5
1.0
0.0
0.5
1.0
0.0
0.5
1.0
1 4 70.0
0.5
1.0
0.0 0.5 1.00.0
0.5
1.0
Inlet loadingSolubility in separator
1 10 1000.0
0.5
1.0
2
0 3 60.0
0.5
1.0
Inlet loadingSolubility in extractor
Birtigh
Membership Functions P Adsorption Membrane
Solubility of solute
Residence time
Solvent ratio
0.0 0.1 0.2
Absorbent
0.0 0.05 0.100.0
0.5
1.0
0.0 0.05 0.10.0
0.5
1.0
0.0
0.5
1.0
0.0 0.05 0.1
in water [g/g]
0.0
0.5
1.0
0.0 0.5 1.0
Inlet loadingSolubility in Separator
1 10 1000.0
0.5
1.0
21 10 1000.0
0.5
1.0
2 1 10 1000.0
0.5
1.0
2
TSeparatorTDecomposition
0.0
0.5
1.0
0.0 0.2 0.4
0 3 60.0
0.5
1.0
0 3 60.0
0.5
1.0
0 3 60.0
0.5
1.0
0 3 60.0
0.5
1.0
0.0
0.5
1.0
0.0 0.1 0.20.0
0.5
1.0
Reduced pressure
1 3 50.0
0.5
1.0 if only 1 phase in Extractor
0.0
0.5
1.0
0.0 0.2 0.4
[min]
if 2 phases in Extractor
Absorption De-Entrain T T
Birtigh
Membership Functions
