Chapter 4 Supercritical Fluids Extraction From Solids-II.
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Transcript of Chapter 4 Supercritical Fluids Extraction From Solids-II.
Chapter 4
Supercritical Fluids Extraction From Solids-II
time
am
oun
t of e
xtra
ct in
so
lid p
ha
se
steady
unsteady
starting
P, T = const.
total amount of extract in feed
amo
unt o
f ext
ract steady unsteady
starting
time
Course of the extraction process
Remaining extract in feed Accumulated extract in sc solvent
Composition of extract changes with conditions of extraction and time
CaffeineTheobromine
Decaffeination of green coffee beans
Lack and Seidlitz 1993
Decaffeination of green coffee beans
Lack and Seidlitz 1993
Flow scheme of decaffeination plant
Schoeller-Bleckmann design
Lack and Seidlitz 1993
Comparison of extraction behaviour
Zwiefelhofer 1990
Composition of liquid CO2 hop extract
Gardner 1993
Rossi et al., 1989
1: Liquor, 40 MPa, 80 oC, 5 h
2: Liquor, 40 MPa, 50 oC, 5 h
3: Nibs, 40 MPa, 80 oC, 5 h
4: Nibs, 40 MPa, 50 oC, 5 h
5: Shells, 30 MPa, 80 oC, 6 h
Fat extraction from cocoa
Standard design
Extractor
Heat exchanger
Cycle gas compressor
Precipitator
Total number of pressure vessels for SFE
Gehrig 1998
100 1000 10000 100000
Throughput feed [t/a]
Batch process
Continuous process
Biggest plant 60 000 t/a
Cost per ton of solid feed [DM]
10000
1000
100
Economy of scale: CO2-extraction from solids
0 500 1000 1500 2000 2500 3000 3500 40000
1
2
3
4
5
6
7
8
mass flow: 18.4 g/min mass flow: 25.8 g/min gradient of the extraction curve; 18.4 g/min; y =0. 00665 gradient of the extraction curve; 25.78 g/min;yyy y
=0 .00663
oil[g]
CO2 [g]
extraction at 300 bar444eeeend4040
Franca, Reber, Meireles, Machado, Brunner, J. Supercritical Fluids 1998
Extraction of Buriti
0 1000 2000 3000 4000 5000-10000
-5000
0
5000
10000
15000
20000
25000
CO2 (g)
Caro
tene
con
cent
ratio
n (p
pm)
0
20
40
60
80
Soxhlet
Am
ount of carotene (mg)
Carotene
Franca, Reber, Meireles, Machado, Brunner, J. Supercritical Fluids 1998
Extraction of Buriti
0,00
0,01
0,02
0,03
0,04
0,05
0 10 20 30 40 50 60g CO2 / g Vorlage
g ASester / g Vorlage
200 bar 60° C
300 bar 60° C
400 bar 60° C
400 bar 70° C
300 bar 40° C
400 bar 40° C
Arachidonic acid from fermentation
Arachidonic acid as methylester extracted from dried filter cakegAAE / gcake
g CO2 / g cake
Extraction of meat products
Effect of varying pressure on the accumulated yield of lipid( left ) and water (right) extracted with supercritical CO2 at 50 oC
R.R. Chao, 1996
Extraction of beef tallow
Cumulative weight of beef tallow extracted by CO2 varying the pressure and temperature
R.R. Chao et al., 1993
Cholesterol concentration in extract
scCO2
Lipid and cholesterol extract from beef tallow.
CO2 and CO2 - ethanol
R. R. Chao et al., 1993
Extraction of beef tallow
Brunner XVII CBCTA - Fortaleza 2000 19
Percent oil removed as a function of volume of CO2 . Feed: Type I: unsalted, Type II: x salted.Extraction P = 408 +/- 6.8 bar, T = 55 +/- 1 oC. Separation: P 2 bar; T = 30 +/-3 oC.
Extraction of oil from chips
S. Vijayan et al., 1994
Extraction of mustard seed oils
300 bar, 40 oC
total amount oil water myrosinase activity
Taniguchi et al. 1987
Extraction of oil from peanuts
CO2
25 oC
Goodrum 1996
Extraction of theobromine from cocoa seed shells
Simon 1990
50 kgCO2/(kgFh) 93 183 304
0 100 200 300 4000
20
40
60
80
1006h
2h
1h
28s
semibatch 25 MPa, 653 K [6] continuous 24 MPa, 663 K
de
gre
e o
f e
xtra
ctio
n
[%]
solvent to soil ratio [kgH
2O
/kgdry soil material
]
Cleaning of Soil
Semibatch and continuous extraction results versus solvent to soil ratio
0 1 2 3 40,0
0,2
0,4
0,6
0,8
1,0
exper i mental data 25 MPa, 650 K, 2.2 kg H2O/ h
degr
ee o
f ex
trac
tion
E
t i me [hour s]
Cleaning of Soil
Course of an extraction of hydrocarbon contaminants rom soil with supercritical water.
Temperature Loading Residence O2 excess Degree of time conversion U
___________________________________________________________________ [°C] [ghc/LH2O] [s] [mol O2/ mohc-mhc)/ mhc
mol O2,min]___________________________________________________________________
290 6.7 135 1.68 0.963
330 0.7 107 26 0.999998
385 3.0 68 6.99 0.9376
Reaction results at 25 MPa, 88 cm3 reactor
SCWO of extracted organic waste from soil
Unterschiedliche Behandlungsmethoden des CND- Bodens:
Wasser ist org. Lösemitteln überlegen
TO
C [
g C
/kg
TS
]Vergleich TOC nach Extraktionen
als Schicht
am Rand
als Kohlenwasser-
stoffpartikel
in den Poren
adsorbiert
im Innern gelöst
Kontaminationsverteilung
ab
c
d
e
f
g
hCO2
2H O
Festbettextraktionsanlage
ac
b
e
d
f
g
Kontinuierlicher Rohrreaktor
Flow sheme of continuous extaction apparatus: Fließbild der kombinierten Anlage: a Vorlagebehälter mit Rührwerk, b Pufferautoklav, c Wirbelbettheizer -Vorwärmer- d Extraktionsstrecke, e Elektrolysezelle im Schutzbehälter, f Doppelrohrwärmetauscher, g Sammelgefäß, h Gasanalysegerät, i evakuierter Glasbehälter
a magnetic stirrer, b membrane pump, c feed vessel, d buffer vessel, e pump, f preheater (28 ml), g extraction pipe (38 ml), h cooler, i flask, j CO2-meter, k evacuated glas vessel.
0.0 2.5 5.0 7.5 10.0 12.5 15.00
20
40
60
80
100
Kohlendioxid50-100°C, 20 MPa
Wasser 380°C, 25 MPa
Lösungsmittelverhältnis [kg LM/kg Boden]
Ext
rakt
ions
grad
[%
]
Realgealterte (20 Jahre) Kontamination (Schluff)
kann mit Wasser vollständig gereinigt werden.
Lösungsmittelvergleich
• Porendiffusion aus
Mikro- in Mesoporen
• Diffusion im Porenfluid
oder Lösungsmittel
• Stofftransport durch
Strömungsgrenzschicht
• konvektiver Stofftransport
mit Lösungsmittelstrom
Transportmechanismen
Kontamination am Feststoff
Partikelporen
Fluidphase
)c
c1(Xk
t
Xpmax
pS1
S
r
c
r
2
r
cD
t
c p2p
2
effp
p
)cc(
1
d
6)cc(
V
VA
t
cfRrp
f
f
pfRrp
f
PartPartf
Strömungsform durch berücksichtigen
Auflösung als Reaktion 1. Ordnung
Modellierung Extraktion
• Suspension als Strähne/Einzel-korn betrachtet
• Dodecan bildet Bezug
0 50 100 150 200 250 300 350 4000
20
40
60
80
100
P = 24 MPa, = 23-49 s, T = 378 - 393 °C
experimentell kombiniertes Modell
Ext
rakt
ions
grad
[%
]
Lösungsmittelverhältnis [kg H2O/kg Boden]
Modellierungsergebnisse
0 50 100 150 2000
20
40
60
80
100
2. Extraktion
1.
3. Extraktion
2.
1.
experimentell (2 Gew.%) simuliert (2 Gew.%) experimentell (3 Gew.%) simuliert (3 Gew.%)
Ext
rakt
ions
grad
[%]
Verweilzeit [s]
P = 24 MPa
T = 381 - 389°C
P = 24 MPa
T = 361 - 381°C
Modellierungsparameter
zur Simulation geeignet
Simulation der Extraktion
0 2 4 6 8 10 12 14 16 18 200
50
100
150
200
250
300
350
CSB° 4502 mg/l
CSB° 2250 mg/l
CSB° 2668 mg/l
t [Tage]
BS
B [
mg/
l]
Extraktionsbedingungen 400°C 3 MPa 380°C 25 MPa 320°C 25 MPa
Beurteilung der biologischen Abbaubarkeit mittels akkumu-lierten Sauer-stoffverbrauchs von Belebt-schlamm
Bruchteil von CSB° wird erreicht
Biologische Abbaubarkeit
25 50 75 100 125 15010
20
30
40
50
60
Verweilzeit [s]
Ext
rakt
ions
grad
Ble
i [%
]
T = 50 °C pH = 3 pH = 4 CO
2
P = 25 MPa
Extraktionsver-mögen liegt im Bereich niedrigerer Temperaturen in Abhängigkeit von der Verweilzeit im Bereich von Essigsäure
Zugabe von Essigsäure zur Einstellung des pH-Wertes
Vergleich mit Essigsäure
100 200 300 400 500 600 7000
20
40
60
80
100
Verweilzeit [s]
Ext
rakt
ions
grad
KW
S [
%] P = 25 MPa
T = 25 °C T = 300 °C T = 340 °C T = 370 °C
Langes Spülen bewirkt Reinigung
Trotz relativ hoher Verweilzeit Reinigung nicht vollständig, trotz nahe-/ überkritischen Bedingungen
Bezug:
60.000 mg/kg
(40.000 mg/kg)
Extraktion der KWSt. (Mischkontamination)
0 50 100 150 200 250 300
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
P = 25 MPa P = 20 MPa (Toews, 1995) P = 15 MPa (Toews, 1995)
pH-v
alue
temperature [°C]
Lowering pH by dissolution of CO2 in H2O
Calculated pH-value of water for carbon dioxide saturated solutions at a pressure of 25 MPa. Equilibrium data from Wiebe (1941), Takenouchi (1964)
Nowak 1995
Solubilities of real hydrocarbon contaminations in water
Water in lubricating oil
EthylbenzeneDimethylcyclohexane
Real weathered extracted contamination
G.M. Schneider
Phase equilibrium:Hydrocarbons in carbon dioxide
Solubility of n-decane in water
0 50 100 150 200 250 300 350
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
Messungen (T oews) P = 10 MPa P = 15.1 MPa P = 20.2 MPa
Berechnung nach Messdaten(Takenouchi)
P = 20 MPa P = 25 MPa P = 30 MPa
Berechnung nach Messdaten (Wiebe) P = 20.2 MPa P = 30.3 MPa
pH
-We
rt
Temperatur [°C]
Abgeschätzter pH-Wert für Kohlensäure, 1. Dissoziationsstufe
Toews et al., 1995
CO2 - H2O
100 150 200 250 300 3500,00
0,02
0,04
0,06
0,08
0,10
0,12
0,14
0,16
0,18
0,20
0,22
200 bar
250 bar
300 bar
400 bar
Lösl
ichk
eit [
g C
O2
/ g H
2O]
Temperatur [°C]Temperature [°C]
So
lub
ilit
y [
gC
O2/g
H2O
]
The solubility of carbon dioxide in liquid water
Biopolymers: Acid catalysis
20 40 60 80 100 1200.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
150 °C
200 °C
250 °C
270 °C
275 °C300 °C
Mo
lan
teil
Ko
hle
nd
ioxi
d in
Wa
sse
r [-
]
Druck [M Pa]
Löslichkeiten von CO2 in Wasser
Takenouchi und Kennedy, 1964
CO2 - H2O
10 20 30 40 50 60 70 80
0.005
0.010
0.015
0.020
0.025
0.030
0.035
Mo
lan
teil
Ko
hle
nd
ioxi
d in
Wa
sse
r [-
]
Druck [MPa]
T = 12°C T = 35°C T = 40°C T = 50°C T = 75°C T =100°C
CO2 - H2O
Gleichgewichtslöslichkeiten von CO2 in Wasser
Wiebe und Gaddy, 1940, Wiebe, 1941
Incentives:
Unrestricted use of site
Remove risk for environment
(water, air, persons, ...
?
Quantities:
Site: 100 m x 100 m
2 m depth
20 000 m3
40 000 t
Remediation II
Solvent ratio kg CO2 / kg soil
De
gre
e o
f ex
tra
cti
on
, % Artificially contaminated
Real contamination,
weathered
Soil extraction with carbon dioxide
Solvent ratio kg CO2 / kg soil
De
gre
e o
f ex
tra
cti
on
, %
Soil extraction
Comparison of CO2 and H2O
25 50 75 100 125 15010
20
30
40
50
60
Verweilzeit [s]
Ext
rakt
ions
grad
Ble
i [%
]
T = 50 °C pH = 3 pH = 4 CO
2
P = 25 MPa
Extraktionsver-mögen liegt im Bereich niedrigerer Temperaturen in Abhängigkeit von der Verweilzeit im Bereich von Essigsäure
Zugabe von Essigsäure zur Einstellung des pH-Wertes
Vergleich mit Essigsäure
Soilmaterial
Washing
Low contaminated fractionreutilization
High contaminatedfraction (smallparticles)
Cleaning Dumping
Thermal(incineration)
SCWSCWO
Othersolvents
biological
Destruction, total oxidation !
Direct route tocleaning
Soil Remediation Method
1 2 3 4Type of contamination diesel
artificialDiesel/lubricat
ing oil;weathered
diesel/lubricating oil;
weathered
diesel/lubricating oil;
weatheredAmount of contamination[mg hc/kg dry solidmaterial]
24418 136587 20231 35066
Age [years] 0.5 20 2 45Type of soil material weak
loamy sandstrong clayey
loamsand strong clayey
sandParticle mean diameter(sphere of equivalentvolume) [mm]
182 18 211 213
Pretreatment - sieved at 710 mm
from washingprocess
sieved at 710 mm
Table 2: Extraction results of real contaminated soil materials (adapted from 7 ).
Soil material from: Petrol Station Industrial Site Old Barrel DepotSauter diameter (m) 30 7 14Contamination lubricating oil
aged 1 yearlubricating oil
aged > 20 yearsPAH
aged > 45 yearsInitial concentration(mg hydrocarbons/ kgdry substance)
20 200 103 500 11 050
ExtractionFinal concentrationmg hydrocarbons/ kgdry substance)
< 20 < 100 < 10
Amount extracted, % > 99.9 > 99.9 > 99.9Temperature , K 663 655 665Pressure , MPa 24 24 25Solvent/soil ratio,kg water/kg drymatter
6 6 12
0 1 2 30
20
40
60
80
100
2
80 °C, 0,32 l/h 80 °C, 0,48 l/h 80 °C, 0,63 l/h 100 °C, 0,77 l/h
Ext
rakt
ions
grad
[%
]
Lösungsmittelverhältnis [kg CO /kg Boden]
TIR
c
TIR
d
TIRTIR
PI
a
M b
TIR TIR
TIC
2COPIRC
fV
N2
g
TICe
h
i
Figure 10: Flow sheme of continuous extaction apparatus: Fließbild der kombinierten Anlage: a Vorlagebehälter mit Rührwerk, b Pufferautoklav, c Wirbelbettheizer -Vorwärmer- d Extraktionsstrecke, e Elektrolysezelle im Schutzbehälter, f Doppelrohrwärmetauscher, g Sammelgefäß, h Gasanalysegerät, i evakuierter Glasbehälter
a magnetic stirrer, b feed vessel, c membrane pump, d buffer vessel, e , f preheater (28 ml), g extraction pipe (38 ml), h cooler, i flask, j CO2-meter, k evacuated glas vessel.
0 100 200 300 4000
100
200
300
400
500
concentration of soil material in water [wt%]
10 0,250,51h
ydro
carb
on
s so
lve
nt
[m
g/l]
solvent to soil ratio [kgH2O
/kgsoil material
]
Figure 12: Concentration of hydrocarbons in the fluid aqueous phase versus concentrationof soil material in water (solvent to soil ratio)at 663 K and 24 MPa.
0 2 4 6 8 100
20
40
60
80
100 E
xtra
ktio
nsgr
ad [%
]
Konzentration Bodenmaterial in der Suspension [Gew%]
Figure 13: Degree of extraction in dependence on the amount of soil material in the solvent (solvent to soil ratio). This diagram corresponds to the left branch of Fig. 12, i.e. up to solvent to soil ratios of 100.T = 663 K, P = 24 MPa, residence time: 28 s.
580 600 620 640 66060
70
80
90
100
de
gre
e o
f e
xtra
ctio
n
[%]
temperature [K]
Figure 14: Extraction results versus temperature at 24 MPa, residence time: 45 s; 1 wt.-%soil in water.
0.0 0.2 0.4 0.6 0.8 1.0 1.255
60
65
70
75
80
85
Bodenkonzentration [Gew.%]
Ext
rakt
ions
grad
Ant
imon
[%
] T = 50 °C T = 100 °C T = 200 °C
Figure 17: Degree of extraction for antimony. P = 25 MPa, material “GKSS”.
1 . D e s o r p t i o n :
maxAgg
AggBodenDe
Boden
X
XCk
tC
1
2 . D i f f u s i o n :
r
Xrr
XD
X
XCk
t
XAg gAg g
effAg g
Ag gBo d enBo d enDe
Ag gAg g
212
2
max
3 . C o n v e c t i o n :
FluidAggSuspensionAgg
FluidSuspension
XXdt
Xr R
16
C o m b i n a t i o n o f s i n g l e p a r t i c l e a n d f i l a m e n t m o d e l :
SträhneEinzelkorn
komb
EEE
)(
Soil Remediation Modelling