Hydrothermal Liquefaction of Algae to Produce

Bio-Oil and Subsequent Catalytic

Deoxygenation to Hydrocarbon

Chao Miao

10.01.2014

Outline

Sequential hydrothermal liquefaction of algae to produce bio-oil

Hydrothermal catalytic deoxygenation of fatty acid to produce hydrocarbon

Conclusion

(A Peterson et al. 2008)

Hydrothermal Liquefaction (HTL)

Reaction media: hot compressed water

Hydrothermal Liquefaction

Combination of cell wall disruption and bio-oil extraction in one step

No organic solvents Requirement

No dewatering step

Easy separation

Mature and commercialized thermo-conversion process

Advantages of microbial biomass hydrothermal liquefaction

Current gaps of direct hydrothermal liquefaction (DHTL) process

to produce bio-oil

(1) Protein and carbohydrate are mostly transformed into bio-char;

(2) Bio-char will decrease the bio-oil separation efficiency;

(3) Sulfur and nitrogen in protein will transformed into bio-oil, bringing environmental issues;

(4) How to recover the valuable co-products, e.g. sugar, polysaccharide, protein, and amino acid.

Technical Gaps

Hypothesis and Concept

Two-step sequential hydrothermal liquefaction to produce bio-oil

Hemicellulose

Starch

Protein

C5 sugar

Glucose

Amino acid

Furfural, 5-HMF

Organic acid

Ammonia, Pyrrol, Indole

Low temperature (160-180C)

Sugar,

Polysaccharide,

Amino acid.

High temperature (240-300C)

Bio-oil,

Bio-char,

Water extractives (WEs).

Above 200 °C

Bio-char

N, S in bio-oil

Low temperature water (150-220°C)

Hydrolyze cell wall of algae

Experiment of SEQHTL

240 °C240 °C140-200C 220-300C

Temperature(C)

130 140 150 160 170 180 190 200 210

Yie

ld (

Wt%

)

0

20

40

60

80

100Polysaccharides

WEs

Dry Treated Algae

(a)

Residence Time(min)

5 10 15 20 25 30 35 40 45

Yie

ld (

Wt%

)

20

30

40

50

60

70Polysaccharides

WEs

Dry Treated Algae

(b)

Biomass/Water Ratio(w/w)

1:6 1:9 1:12

Yie

ld (

Wt%

)

10

20

30

40

50

60

70Polysaccharides

WEs

Dry Treated Algae

(c)

Results of 1st step SEQHTL (Algae)

The polysaccharide could be separated with 1:9

algae/water ratio at 160C, within 20min, which is

optimal condition for 1st step of SEQHTL in the

studied condition

SEQHTL Vs DHTL

Temperature (C)

220 240 260 300

Bio

-oil

Yie

ld (

wt%

)

0

10

20

30

40 SEQHTL

DHTL(a)

Bio-oil produced through SEQHTL showed a

higher yield than DHTL.

For bio-oil production through SEQHTL, the

optimal condition is suggested at 240C, with 1:6

biomass/water ratio within 30min.

Temperature (C)

220 240 260 300

Bio

-ch

ar Y

ield

(w

t%)

0

10

20

30

40

50

SEQHTL

DHTL

(b)

Bio-char and WEs produced through SEQHTL

showed a significant lower yield than DHTL.

The lower yield is attributed to the

prior removal of polysacchride and sugar in the

first step of SEQHTL.Temperature (C)

220 240 260 300

WE

s Y

ield

(w

t%)

0

5

10

15

20

SEQHTL

DHTL

(c)

Fatty Acids Composition in Bio-oil

Bio-oil produced through SEQHTL showed

higher fatty acid content than DHTL.

The major components in bio-oil are

palmitic, oleic, linoleic acid.

Temperature (C)

220 240 300

Perc

en

tag

e o

f F

att

y A

cid

s in

Bio

-oil (

Wt%

)

0

20

40

60

80

100

SEQHTL

DHTL

Fatty acid Structure DHTL

220˚C

mg/g

SEQHTL

220˚C

mg/g

DHTL

240˚C

mg/g

SEQHTL

240˚C

mg/g

DHTL

300˚C

mg/g

SEQHT

L 300˚C

mg/g

Palmitic C16:0 190.79 242.44 198.14 217.97 191.71 192.70

Hexadecenoic C16:1n9 44.93 55.93 46.22 49.08 33.50 41.37

Hexadecadienoic C16:2n6 23.18 28.15 23.13 24.02 8.11 12.22

Stearic C18:0 17.81 22.42 19.24 20.50 19.77 20.24

Oleic C18:1n9 167.67 241.34 202.23 221.82 136.97 200.97

Linoleic C18:2n6 213.50 262.66 213.83 228.13 65.61 101.81

Linolenic C18:3n3 28.34 32.12 25.18 26.41 3.96 3.45

Others 77.01 59.81 64.16 60.57 213.16 131.3

Total Fat 763.23 944.87 792.13 848.50 672.79 704.06

Upgrading of Bio-oil

Issues of bio-oil produced by hydrothermal liquefaction

High melting point

High pour and cloud point

High viscosity

Fatty acid

AcylglycerideHigh oxygen content

Deoxygenation

Hydrodeoxygenation (HDO)

Decarboxylation/decarbonylation (DeCOx)

High pressure of H2

Moderate temperature (250-350C)

Metal-based catalyst.

(1) Noble metals supported on metal oxide, or

zeolite;

(2) Sulfide metals supported on alumina.

Decarboxylation does not require H2

Decarbonylation requires small amount of H2

Temperature (300-400C)

Metal-based catalyst.

(1) Metal site: Pd, Pt, Ni.

(2) Support: activated carbon, metal oxide,.

Deoxygenation

Technical issues

1. High cost of noble metal (Pd, Pt) used as industrial scale catalyst

2. Low fatty acid conversion over Ni-based catalyst under no external H2

1. Hydrogen can be produce by reforming and water-gas shift reaction

2. It is potential to integrate SEQHTL process with hydrothermal catalytic doxygenation

process to produce hydrocarbon.

Our concept

Hydrothermal catalytic deoxygenation of fatty acid to produce hydrocarbon with in-situ

formed H2 from fatty acid

Catalyst-Ni/ZrO2

Why Ni/ZrO2:

Ni and ZrO2 are low cost catalysts compared with noble metal

ZrO2 is a very good support providing oxygen vacancy

ZrO2 is a very stable and catalytic active in subcritical water phase (<350C)

Deoxygenation activity: Pd>Pt>Ni>Rh>Ir>Ru>Os

Effect of Reaction Temperature

Liquid Products (%)

Total liquid paraffins

(%) Gas Products (%)

Total Hydrocarbon

(%)

T (°C) C15 C16 C8-C14 C8-C19 CH4 CO2 C2H4 C1-C19

250 2.8 0.0 0.0 2.8 0.1 0.0 0.0 2.9

270 18.9 0.8 0.0 26.9 0.2 0.0 0.0 27.1

290 34.6 4.0 21.4 60.5 18.6 5.5 0.1 79.1

300 30.2 2.8 26.0 59.5 27.6 5.1 0.3 87.1

Increased temperature improved fatty acid

conversion and paraffin yield.

Yield of products

Effect of Water on Reaction

Presence of water increased fatty acid

conversion and paraffin yield

Presence of water suppress side reactions:

(a) ketonization and (b) esterification

Hydrothermal Deoxygenation with In-situ H2

Fatty acid conversion and paraffin

yield were increased with the reaction

time.

Hydrogen was in-situ produced at 2-5

mole per mole of fatty acid

Oxygen is increased by ~60% after the

reaction.

Before (mol) After (mol)

0.0035 0.0058 Oxygen Balance

Reaction Time (h)

0 2 4 6 8 10 12 14

Co

nve

rsio

n o

f S

A o

r Y

ield

of p

ara

ffin

0

20

40

60

80

100

Conversion

Paraffins yield

Reaction Pathway-Liquid Phase

C15H31COOH

C15H32

C16H34C16H33OH

C15H31COOC16H33

+H2

-H2O, -CO

Decarbonylation

Decarboxylation

-CO2

+2H2

-H2O

+H2

-H2O

-H2O

Esterification

+H2, Hydrogenolysis

-CH4

C8-C14 ParaffinsAqueous reforming

-CO2, -H2

C15H31COC15H31-H2O, -CO2

Ketonization+C15H31COOH

(a)

Conclusion

A two-step sequential hydrothermal liquefaction method was developed to produce bio-oil,

carbohydrate, and protein from algae.

Comparing SEHQTL with DHTL, The amount of bio-char was reduced >50% after

removing carbohydrate and protein. The removed WEs could be used as carbon and nitrogen

nutrients.

The removal of carbohydrate and protein did not significantly influence the quality and

quantity of bio-oil. On the contrary, SEQHTL bio-oil extracted at lower temperature seemed

to have higher fatty acid contents.

The produced bio-oil from SEQHTL process can be upgraded through hydrothermal catalytic

deoxygenation to directly produce hydrocarbon.

Compared with traditional deoxygenation process (in the absence of water but presence of

H2), hydrothermal catalytic deoxygenation method is able to remove oxygen from bio-oil

with no external H2

Decarbonylation is the major deoxygenation route over Ni/ZrO2 catalyst. Hydrothermal

reforming and water-gas shift reaction are the main reactions for the formation of in-situ H2.

Thank you