Procesado de aceite de algas

Downstream processing of algal oil

Emilio Molina GrimaDpt. Chemical Engineering, University of Almería, SPAIN

[email protected]

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



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



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)


n-Butanol

EtOH 96%

EtOH 96%/H2O (1:1 v/v)

Hexane/Isopropanol (1:1.5 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

JOSE Y MARIAJOSE

La segunda fase no es con hexano cuando el sistema lleva etanol?




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




Yields (%) of Extracts and Raffinates (in parentheses) of lipids extraction from dry Isochrysis galbana




Butanol

EtOH 96%

EtOH 96%/H2O (1:1 v/v)


92.9 (0.9)

52.2 (27.4)

49.5 (8.3)

70.4

84.4

63.3

66.0

Solvent Mixture



Extraction of fatty acids

Yields (%) of Extracts obtained by direct saponification from dry Isochrysis galbana



Hexane/EtoH 96% (1:0.9 v/v)

Butanol

EtOH 96%

EtOH 96%/H2O (1:1 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


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



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)




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




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




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




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



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


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

JOSE Y MARIAJOSE

Hay que cambiar el 2.26 L por la cantidad en g pero no tengo el archivo con ese dato. Comprueba el dato lo he calculado y sale 1,53 kgHay que expresar las corrientes de disolvente en gramos?




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

JOSE Y MARIAJOSE

La frase no esta al pie de la letraFalta poner x1 y x2




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




E. Molina Grima et al. (1996) Spanish patent 9602090


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

JOSE Y MARIAJOSE

Los dos digramas de flujo de Hassan estan en español no recuerdo los comentarios sobre ellos.No recuerdo tampoco si habia que poner los dos o solo el simplificado que viene despues



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


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)



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



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)


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



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%



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



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


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

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