Post on 11-May-2015
description
transcript
Downstream processing of algal oil
Emilio Molina GrimaDpt. Chemical Engineering, University of Almería, SPAIN
emolina@ual.es
Seminar on Microalgae IMDEA Energy-EOI, April 8 2010, Madrid
2Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
1. No well-defined demonstration industrial plants
2. Microalgae differ from other bioenergy feedstocks in:• Cell wall chemistry• Large amount of water• Small cell size• Much more polar lipids than traditional crops
3. Extraction of lipids from algae requires attention to their polarity
4. The strain and the harvest time will determine the solvent election
Questions to take into consideration
3Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Lip
id c
on
ten
t (w
t %
)
Non-disruption
Autoclaving
Bead-beating
Microwaves
Sonication
Osmotic shock
30
20
10
0
30
20
10
0
30
20
10
0
Botryococcus sp
Chlorella vulgaris
Scenedemus sp
Pretreatment of microalgae cells
J.Y. Lee et al. (2009) Bioresour Technol. DOI10.1016/j.biotech2009.03.058
Comparison of several methods for effective lipid extraction from microalgae
4Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Extraction of lipids
Solvent Mixture (dry Isochrysis galbana)
Cl3CH/MeOH/H2O (1:2:0.8 v/v/v)
Hexane/EtOH 96% (1:2.5 v/v)
Hexane/EtOH 96% (1:0.9 v/v)
n-Butanol
EtOH 96%
EtOH 96%/H2O (1:1 v/v)
Hexane/Isopropanol (1:1.5 v/v)
Cl3CH/MeOH/H2O (1:1:0.9 v/v/v)
Hexane/EtOH/H2O (6:1:1 v/v/v)
Hexane/EtOH/H2O (29:4.7:1 v/v/v)
Cl3CH
Cl3CH
Cl3CH
Cl3CH
Extraction (monophasic) Purification (two phases)
E. Molina Grima et al. (1994) JAOCS, 71(9), 955-959
5Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Extraction of lipids
Information on saturation curves may be found at:
Walter D. Bonner (1910). Experimental Determination of Binodal Curves, Plait Points, and tie lines, in Fifty systems, each consisting of water and two organic liquids. J. Phys. Chem. 14, 738-789
E. Molina Grima et al. (1994) Comparison between extraction of lipids and fatty acids from microalgal biomass. JAOCS, 71(9), 955-959
Optimal tie line
6Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Extraction of lipids
Yields (%) of Extracts and Raffinates (in parentheses) of lipids extraction from dry Isochrysis galbana
Cl3CH/MeOH/H2O (1:2:0.8 v/v/v)
Hexane/EtOH 96% (1:2.5 v/v)
Hexane/EtOH 96% (1:0.9 v/v)
Butanol
EtOH 96%
EtOH 96%/H2O (1:1 v/v)
Hexane/Isopropanol (1:1.5 v/v)
92.9 (0.9)
52.2 (27.4)
49.5 (8.3)
70.4
84.4
63.3
66.0
Solvent Mixture
7Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Extraction of fatty acids
Yields (%) of Extracts obtained by direct saponification from dry Isochrysis galbana
Cl3CH/MeOH/H2O (1:2:0.8 v/v/v)
Hexane/EtOH 96% (1:2.5 v/v)
Hexane/EtoH 96% (1:0.9 v/v)
Butanol
EtOH 96%
EtOH 96%/H2O (1:1 v/v)
Hexane/Isopropanol (1:1.5 v/v)
Solvent system + KOH (47.5 mL solvent /g KOH)
-
81.0
48.0
9.0
79.8
46.5
62.0
60ºC-1 h
-
75.0
47.1
-
79.2
45.5
61.1
Room-8 h
8Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of AlmeríaComparison between the extraction
of Lipids and Fatty acids I. galbana
1. Alcohol content seems to be the main factor in lipid
extraction. The higher the polarity of the co-solvent,
the higher the yield
2. For each solvent mixture the yield of lipid extraction
is slightly higher than that of fatty acid extraction
3. Direct saponification of the biomass could be
induced in two steps, being the lipid extraction the
bottleneck
A LARGE AMOUNT OF SOLVENT WAS USED
144 mL/g of dry biomass
9Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Optimization of fatty acids extraction
480 g Wet biomass(100 g d.b)
ethanol (1 L)
KOH
ethanol (0,5 L)
Residue Raffinate (underflow)
Alcoholic solutionFatty acids soaps
(25% water)
S-L(W)
S-L
Fatty acids
hexane hexane hexane hexane
L-L L-L L-L L-LAlcoholic
phasepH6
Alcoholic solutionFatty acids soaps
(25% water)
water
Alcoholic solutionFatty acids (40% water)
HCl
Ramírez Fajardo et al., 2007
810 g 405 g
Extract (overflow)
10Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Optimization of fatty acids extraction
Influence of Ethanol (96%)/wet biomass
Ethanol (96%)/ wet
biomass (ml/g)
Ethanol (96%)/ dry
biomass (ml/g)
% Ethanol
(v/v)
Fatty acid
yield (%)
1.05 5 55 86.0
2.09 10 70 87.0
2.93 14 76 86.3
3.97 19 80 86.9
7.94 38 87 88.5
11.91 57 90 90.6
18.88 76 92 90.4
19.86 95 92 90.0
- 76 96 96.2
M.J. Ibañez González et al. (1998) JAOCS 75, 1735 – 1740.
Lyophilized
11Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Optimization of fatty acids extraction
V01= 810 g
(1 L ethanol)
+21 g KOH
Residue
Alcoholic solutionFatty acid soaps
(25% water)
21
V1+V2 = 1336 g
yA =0.0072
V02= 405 g
(0.5 L ethanol)
L1
XA1
XB1
XS1
Lo =480 g
XA0= 0.023
XB0= 0.977
L2
XA2
XB2
XS2
Wet Biomass(100 g d.b)
Recovery Yield87%
S-L stage
12Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Optimization of fatty acids extraction
V01= 810 g
(1 L ethanol)
Residue
Alcoholic solutionFatty acid soaps
(25% water)
21
V1+V2 = 1336 g
yA = 0.0072
V02= 405 g
(0.5 L ethanol)
L1
XA1
XB1
XS1
Lo = 480 g
XA0= 0.023
XB0= 0.977
L2
XA2
XB2
XS1
Wet Biomass(100 g d.b)
Recovery Yield91%
V0
BL0 A
S
xA0
V1
M1
V2
L1
L2
M2
Kg FA soaps solution
Kg inert solidP= = 3
Scale-up calculations needed(repeated contact system)
XA1
1- XB1
YA1= (Ideal stage)
LA0 + V01 = L1 + V1 = M1
XA0·LA0 = YA1·V1 + XA1·L1
S-L stage
underflow
overflow
xA2
L0 XB0 = L1 XB1
13Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Optimization of fatty acids extraction
A
S
B
V2
V1
xA2 xA0
LnL2
L
1
M
L0
Vn+1
21
V1 yA1
L1
XA1
XB1
XS1
Lo =480 g
XA0= 0.023
XB0=0.977
L2
XA2
XB2
XS2
V2 yA2 V0 =1215 gExtract (overflow)
Raffinate(underflow)
Δ
Scale-up calculations needed(counter current systems)
S-L stage
14Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Fatty acid yield (%)
Extraction step Step step Equilibrium data
1 78.6 78.6 81.0
2 11.2 89.8 96.7
3 4.7 94.5 99.4
4 1.9 96.4 99.9
Optimization of fatty acids extraction
Fatty acidsExtract
(Hexane phase)
V0= 0.026 LHexane
V0= 0.026 LHexane
V0= 0.026 LHexane
Alcoholic phase
Alcoholic solutionFatty acids (40% water)
L-LL-LL-LL-L
V0= 0.026 LHexane
Lo = 1,53 kg
XA0= 903 mg/L L1
XA1
L2
XA2
L3
XA3
L4
XA4
L-L Extraction of FA
V1 y1 V1 y2 V1 y3 V1 y4
15Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Optimization of fatty acids extraction
Fatty acids concentrationAlcoholic phase CFA (mg·L-1)
The distribution equilibria of FA between the alcoholic phase and hexane facilitate the calculation of design, scale-up and assessment purposes
0
1000
2000
3000
4000
5000
6000
0 50 100 150 200
Fat
ty a
cid
s c
on
cen
trat
ion
Hex
ane
ph
ase,
CA
H (
mg
·L-1)
Step1
Step 2
Equililbrium
x1 x2
L/V
930 mg L-1
16Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Optimization of fatty acids extraction
Conclusions
FA recovery yield (wet biomass)
FA recovery yield (dry biomass)
Important reduction of hexane
Important reduction of alcohol (96% v/v)
Solvent/biomass
87%
96,2%
90%
84%
24 mL/g biomass
17Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Optimization of fatty acids extraction
E. Molina Grima et al. (1996) Spanish patent 9602090
18Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of AlmeríaDirect transesterification of paste Biomass
Biodiesel
BIOMASS
HEXANE
ACETONE
EPA
METHANOL
RESIDUE
ACETYL CHLORIDE
WARTER
CONDENSER
MIXER
EV
AP
OR
AT
OR
CROMATOGRAPHY
CENTRI-FUGE
FILTER
SOLIDS
EXTRACTOR
REACTOR
ULTRASONICMIXER
OPCIONAL
OPTIONAL
E Belarbi et al. (2000). Enzyme and Microbial Technology 26 516-529 .
EV
AP
OR
AT
OR
COOLER
EV
AP
OR
AT
OR
19Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Paste biomass
Hexane
Methanol
Acetyl chloride/ H2SO4 (10%)
Extractor
Cooler FAMEs
Spent biomass
Centrifugation
Filtration
1000 mL
*500 g
50 mL
1000 mL
Temperature = 100 ºC
Time: 120 min 9.1 g
*(500 g of paste biomass of Phaeodactylum tricornutum ≈ 100 g of lyofilized biomass)
(9.9% of TFAs)
EV
AP
OR
AT
OR
500 mL
Extractor
Condenser
Direct transesterification of paste BiomassPhaeodactylum tricornutum- Monodus subterraneus – Scenedesmus almeriensis
20Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of AlmeríaDirect transesterification of paste Biomass
V01= 605 kg/day
Hexane
ResidueS-L2
S-L1
V1+V2 = 773 kg/day
yA =0.0483
V02= 303 kg/day
Hexane
L1
XA1
XB1
Lo =3190 Kg/day
XA0= 0.013
XB0=0.987 L2
XA2
XB2
ReactionL= 1375 Kg/day
XA0= 0.03
XB0=0.997
Wet biomass
1815 kg/day
methanol +
acetyl chloride or
10% H2SO4
Hexane solution ofmethyl esters
S-L
2
S-L
1
V1 = 395,15 kg/day
yA1=0.095
L1
XA1
XB1
L2
XA2
XB2
V2 yA2 V0 =530 kg/day
Lo =3190 kg/day
XA0= 0.013
XB0=0.987
Residue
Hexane solution of methyl esters
Hexane
CASE STUDY
Slurry reaction products(Spent biomass, water,methanol, FAMES, catalyst)
Biodiesel produced per year:13.550 kg
Calculations needed for processing the paste biomass produced per day in one Ha of tubular photobioreactors of Scenedesmus almeriensis.
Slurry reaction products(Spent biomass, water,methanol, FAMES, catalyst)
21Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Paste Biomass
Hexane
Methanol
Acetyl chloride / H22SO44
REACTORCooler
Centrifugation
Filtration
Spent Biomass
** Biodiesel
*** EPA
EXTRACTOR
* Biodiesel
Argentated silica gel column chromatography
Hexane: Acetone
(99.5: 0.5 v/v)
EPA (99%): 2154 $/ Kg
EPA (70%): 185 $/ Kg
(Abayoumi et al., 2009)
1500 mL
500 g
50 mL
1000 mL
(9.9 % of TFAs)
(9.1 g)
(6.9 g)
(1.6 g)
(76%)
(18%)
EXTRACTOR
Cooler
Direct transesterification of paste Biomass
* Crude biodiesel with high content of EPA (27.7%) and a 92% recovery yield with respect to the total FA contained in the biomass
** Biodiesel with low EPA content (8.2%) and a 76% recovery yield with respect to the total FA contained in the biomass
*** High grade EPA methylester (96.4%). Recovery yield 18% with respect to the total FA contained in the biomass.
EV
AP
OR
AT
OR
22Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Comparison of experimental conditions and yields obtained by direct transesterification of microalgae biomass and other feedstocks
FeedstockWet biomass
500 gJatropha curcas seeds
20 g
Solventto extract FAMES
Catalyst
Methanol
Biomass/tissue
Working conditions
Yield
Fresh tissues of olive oil fruit50-200 mg
E. Belarbi et al.(2000)
Siew Hoong et al.
(2010)
R. Garces and M. Mancha (1993)a
G. Lapage and C.C.Roy (1984)b
Maternal milk or adipose tissue
10 mg
Hexane HexaneHeptane
Benzene or TolueneBenzene
SO4H2 5% wt(CH3COCl 5%)
SO4H2 15% wt SO4H2 2% wt SO4H2
2 v/w 7,5 v/w 25 v/w 100 v/w
2 h, 100ºC2,5 atm
24 h, 60ºC 1-2 h, 80ºC 10 min, 80ºC
>90% >99% >95% >98%
a) Methylating mixture: mtehanol:heptane:benzene: 2,2 diemthoxypropane: SO4H2 (37:36:20:5:2)b) Methylating mixture: methanol:benzene (3:2)
23Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of AlmeríaExtraction and Fractionation of microalgal Lipids
Conclusions
Technology seems to be developed at lab scale so far
Nowadays any pilot or demonstration plant will not be efficient or
cost-effective, but it surely evolve to a greater efficiency and less
operating cost process
Other components such as carbohydrates and proteins may need
multi-step processes
24Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Multi-step process
4. Protein and carbohydrate separation from non lipidic residue
CarbohydratesProteins
Precipitation
1. Protein and carbohydrate extraction from wet biomass
Biomass slurry
Wet Biomass
Solid-Liquid Extraction
Precipitation
ProteinsCarbohydrates
3. Chlorophyll separation from non lipidic residue
Enriched in ethanol
VACUUM BATCH DISTILLATION
Filtration
Chlorophylls
2. Fatty acid extraction by direct saponification and recovery of
unsaponifiable products (carotenoids)Carotenoids
Spent biomassLiquid-Liquid Extraction
Fatty Acids
Saponification
Filtration
Liquid-Liquid Extraction59,0%
91%
6,6% Chlorophyll a10,8% Chlorophyll c
41,0%16,3%
15,5%
25Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
Multi-step process
Carotenoids in hexane0.33 g
L-L L-L L-L
0.9 Lhexane
L-L L-L
0.9 Lhexane
0.9 Lhexane
0.9 Lhexane
Alcoholic phase
0.9 Lhexane
S-L, solid-liquid extractionL-L , Liquid-Liquid extractionP, Precipitation
S-L
1.5 Lbuffer
S-L
1.5 Lbuffer
476 gWet
biomass(100 g d.b)
Proteinsin the pellet
17.7 g
P(NH4)2SO4 Carbohydratesin water
1.7 g
0.3 Lwater
S-L
residue40 g KOH
1 L ethanol
S-L
0.5 L ethanol
26Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of Almería
pH 6
HCl
Alcoholic Phase
Fatty acids in hexane8.0 g
L-L L-L L-L
0.45 Lhexane
L-L
0.45 Lhexane
0.45 Lhexane
0.45 Lhexane
D, DistillationF, FiltrationP, PrecipitationL-L , Liquid-liquid extraction
D Carbohydratesin water
enriched in ethanol
F P
(NH4)2SO4
Chlorophyllsin torte
Chlorophylls a 0.0753 gChlorophylls c 0.0378 g
Proteins in pellet6.7 g
Multi-step process
27Seminar on Microalgae IMDEA Energy-EOI, April 8, 2010. Madrid
Chemical Engineering DepartmentUniversity of AlmeríaDownstream processing of algal oil
Acknowledgements
Antonio Giménez Giménez
Alfonso Robles Medina
Maria Jose Ibáñez González
Jose M. Fernandez-Sevilla
Francisco Gabriel Acién Fernández
Emilio Molina Grima
El Hassan Belarbi