Nikos Papayannakos, Professor National Technical University of Athens

School of Chemical Engineering Unit of Hydrocarbons and Biofuels Processing

Upgrading of Bio-oils from Biomass with Catalytic Hydrotreatment

8 March 2013

UGent Francqui Chair 2013 / 4th Lecture

Introduction Ligocellulosic Biomass Conversion to Liquid Bio-Oils Hydrotreatment of Bio-Oils Pre-treatment Post-treatment Co-Processing Current trends in research Conclusions

Outline UGent/FCh13/4L

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Biomass : Sustainable Feedstock

Can replace diminishing fossil Fuels to produce

Energy Chemicals

Three General Classes of feedstocks derived from Biomass

Starchy Lignocellulosic

Oils

Biomass UGent/FCh13/3L

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UGent/FCh13/4L

• Polysaccharides with a-glycosidic bonds • Structural Units : Glucose • Solar Energy Store

Amylopectin 75 – 80 wt %

Amylose 20 – 25 wt %

Linkages

α (1-6)

Linkages

α (1-4)

Easily hydrolyzed into the constituent sugar monomers

BIOETHANOL 1st Generation Biofuel

The easily processed Sugars and Triglycerides are only a small part of the Biomass Poor Energy Yields

Starchy Feedstocks UGent/FCh13/4L

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Disadvantages of 1st Gen. Biofuels

Lignocellulosic biomass is :

• Inexpensive and The most abundant class of Biomass • Present in all plants contributing structural integrity

Lignocellulosic Biomass is comprised of :

Cellulose is a crystalline, strong and resistant to hydrolysis Polysaccharide with b (1-4) glycosidic linkages

Hemicellulose is a Polysaccharide with a random Structure and little strength. It is easily hydrolyzed by dilute acids, bases and enzymes

Lignin is an amorphous Polymer composed of methoxylated phenylpropane structures

40 – 50 wt % 25 – 35 wt %

15 – 20 wt %

Lignocellulosic Biomass UGent/FCh13/4L

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• Convert the solid biomass into Gas or Liquid platforms • Partial removal of Oxygen

The goal of converting lignocellulosic biomass to hydrocarbon fuels

Remove Oxygen Increase the energy density

Control MW / formation C-C bonds

Catalytic Upgrading to final Biofuel • Removal of the remaining Oxygen • C-C coupling controlled reactions

1st Step / Conversion

2nd Step / Upgrading

Thermochemical Hydrolysis Sugar monomers/ Upgradable intermediates

Whole Biomass Deconstruction

Biomass Conversion UGent/FCh13/4L

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Final BIOFUEL

Pathways to convert sugars and polyols to biofuel through production of monofunctional intermediates1,2

1 E. L. Kunkes, D. A. Simonetti, R. M. West, J. C. Serrano-Ruiz, C. A. Gartner and J. A. Dumesic, Science, 2008, 322, 417–421 2 David Martin Alonso, Jesse Q. Bond and James A. Dumesic Green Chem., 2010, 12, 1493–1513

Hydrolysis Routes UGent/FCh13/4L

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Hydrolysis Route through Sugar/Polyols Monomers

Reaction pathways to upgrade HMF by aldol-condensation to liquid alkanes

G.W. Huber, J.N. Chheda, C. J. Barrett and J. A.Dumesic, Science, 2005, 308, 1446–1450

Hydrolysis Routes UGent/FCh13/4L

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Most Important Technologies of thermo-chemical conversion for Liquid Biofuel production

Gasification

Pyrolysis

Production CO/H2

F-T Conversion Into linear CxHy

Finishing - Isomerization

Fast Pyrolysis

Slow Pyrolysis

Bio-oil Production

Char Production

Bio-oil Hydrotreatment

Hydrothermal Liquefaction

Bio-oil Production In the presence of water

Bio-oil Hydrotreatment

Processes for Liquid Biofuels UGent/FCh13/4L

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BIOFUEL

BIOFUEL

BIOFUEL

Thermochemical Conversion of Biomass

Thermochemical Processes UGent/FCh13/4L

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R.W. Nachenius, F. Ronsse, R.H. Venderbosch, W. Prins Advances in Chemical Engineering, Vol. 42, Burlington: Academic Press, 2013, pp. 75-139

Composition of Pyrolysis Bio-Oils

The exact composition depends on the • Biomass Soure and • Process Conditions

A Typical Composition of a Bio-Oil : Pyrolitic lignin and suspended solids : 22-36% pH : 1.8 – 3.8 Water : 20-28% Density : 1.2 – 1.3 g/cm3 Hydroxyacetaldehyde : 8-12% Oxygen : 40 – 50 % Levoglucosan : 3-8 % LHV : 10 – 15 MJ/Kg Acetic Acid : 4-8% Cetane N. : 10 Formic acid : 3-6% Formaldehyde : 3-4% Acetone : 3-6% Cellobiosan : 1-2% Glyoxal : 1-2%

They contain : Acids, Alcohols, Ketons, Aldehydes, Phenol

http://en.wikipedia.org/wiki/Pyrolysis_oil

Composition of Bio-Oils UGent/FCh13/4L

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The most common types of molecules in Bio-oils from Lignin derive from the building blocs of Lignin ( Monolignols )

Monolignols UGent/FCh13/4L

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The most common types of linkages in bio-oils from Lignin

β-O-4 linkage

OCH3

OOH

HO

O

OH

CH3

1) Aryl ether β-O-4 linkage between one aromatic ring and an oxygen atom that is bounded to a carbon atom of an alkyl substitute of another aromatic ring

2) Phenylcoumaran β-5 linkage between one aromatic ring and the carbon atom of the coumaran ring.

Linkages in Lignin derived molecules UGent/FCh13/4L

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β - 5 linkage

3) Biphenyl 5-5’ linkage between two different aromatic rings

O

OH

HO

OH3C

CH3

HOOC

COOH

5-5’ linkage

4) Pinoresinol β-β linkage between two tetrahydrofurans which are bonded together but also to an aromatic ring each

OH

OH3C

O

O

HO

OCH3

β-β linkage

UGent/FCh13/4L

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Linkages in Lignin derived molecules

5) Dibenzodioxocin 5-5-O-4 linkage between two aromatic rings but also between an aromatic ring and a carbon atom of a methoxy group attached to another ring.

5-5-O-4 linkage

O

OCH3

COOH

COOH

O

CH3O

CH2OH

HO

OH3C

UGent/FCh13/4L

8 March 2013

Linkages in Lignin derived molecules

Typical Gas Composition at various pyrolysis temperatures

Wang X., Kersten SRA., Prins W., van Swaaij WPM. Ind. Eng. Chem. Res., 2005, 44(23), 8786-8789

Pyrolysis Gas Composition UGent/FCh13/4L

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Properties of the Pyrolysis Bio-Oils

After Fast Pyrolysis the bio-oil shows some intrinsic disadvantages for its use as a neat biofuel or in blends with other petroleum fractions

These drawbacks are strongly related to the Pyrolitic Lignin molecules and

the functional groups of the existing compounds

Bio-oil tends to polymerize during long storage periods It has poor heating value It has poor thermal stability It is non-volatile It has high viscosity It is highly corrosive due to the presence of carboxylic acids It is immiscible with fossil fuels (diesel)

Characteristics of Bio-Oils UGent/FCh13/4L

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Basic Characteristics :

Bio-Oil Pretreatment

For the effective HDT and storage of the Bio-oils stabilization is attempted

Catalytic treatment during pyrolysis

Catalytic Post-treatment after Pyrolysis

Advantages

Disadvantages The catalyst operates ONLY at Pyrolysis conditions

The catalyst can operate at Different conditions One step Process

Another reactor is needed After Pyrolysis

The composition and the properties of the final Bio-Oil Depend on the biomass feed material, the pyrolysis conditions and the stabilization treatment

Aging is accelerated with temparature because polymerization reactions are promoted

Alternative pretreatments UGent/FCh13/4L

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Raw material, catalyst and reaction conditions of pyrolysis – stabilization Processes

Hydrotreatment of Bio-Oils

Efficient Design and Operation of Hydrotreaters

A good knowledge of the chemical composition of Bio-oils

What are the compounds (group) or the functional groups/structures that control aging and instability? How can we eliminate them or their action? How can we minimize the Oxygen amount in the final Bio-Oil?

Hydrotreater simulation UGent/FCh13/4L

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Before Hydrotreatment the pre-treatment process must be controlled

Alternatives in Hydrotreating

Mild Hydrotreatment

• Stabilization • Production of oxygenated compounds

Chemicals Fuels

HDT – Hydrodeoxygenation

- Remove Oxygen - Hydrogenate Aromatics

HDT – Hydrocracking

- Reduce molecular size

Bio-Fuels

Hydrotreating UGent/FCh13/4L

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Co-Process with Petroleum Fractions

Elliott D. C. WIREs Energy Environ 2013. doi: 10.1002/wene.74

Typical Flow Diagram of Bio-Oil Hydrotreatment

HTD - HC UGent/FCh13/4L

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Component group Feed 1 (%) O1 (%) Feed 2 (%) O2 (%) O3 (%) Unsaturated ketones/aldehydes 3.37 0.98 4.46 0.00 0.39

Carbonyls (hydroxyketones, aldehydes)

9.27 3.27 9.36 0.00 0.00

Total alkanes 0.00 9.86 0.00 4.45 3.18 Saturated guaiacols (diol,ones) 0.00 0.15 0.00 0.29 0.71

Phenol and alkyl phenols 10.27 13.86 6.83 18.55 26.67

Alcohols and diols 3.50 4.62 9.31 5.29 1.94

HDO aromatics 0.00 0.81 0.00 0.87 0.27 Total saturated ketones 1.13 21.00 0.96 25.08 17.68

Total acids and esters 19.78 23.43 41.81 25.21 25.68

Total furans and furanones 8.50 1.09 3.01 2.19 1.52

Total tetrahydrofurans 3.18 3.26 2.88 4.65 2.35

Complex guaiacols 26.40 9.49 8.34 4.57 7.70 Guaiacol and alkyl guaiacols 7.77 5.00 6.71 5.41 6.70

Unknowns 6.83 3.17 6.32 3.44 5.21 Total 100.00 100.00 100.00 100.00 100.00

Composition of Feeds and hydrotreated products ( O1, O2 and O3)

Douglas C. Elliott*, Todd R. Hart, Gary G. Neuenschwander, Leslie J. Rotness, Alan H. Zache Environmental Progress & Sustainable Energy, 2009, 28(3) 441-449

HDT-Feed and Product Composition UGent/FCh13/4L

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Component groups O1 (%) O2 (%) O3 (%) O4 (%) Feed 1 (%) Unsaturated ketones 0.00 0.00 0.00 0.00 0.00 Carbonyls (hydroxyketones) 0.00 0.00 0.00 0.00 0.00

Naphthenes 70.77 67.88 69.67 71.63 4.22 Saturated guaiacols (diol,ones) 0.00 0.00 0.00 0.00 0.00

Phenol and alkyl phenols 0.00 0.00 0.00 0.00 15.68

Alcohols and diols 0.00 0.00 0.00 0.00 22.67 HDO aromatics 12.02 14.05 11.53 12.82 10.51 Total saturated ketones 0.00 0.00 0.00 0.00 12.84

Total acids and esters 0.00 0.00 0.00 0.00 11.89

Total furans and furanones 0.00 0.00 0.00 0.00 0.00

Total tetrahydrofurans 0.00 0.00 0.00 0.00 3.28

Complex guaiacols 0.00 0.00 0.00 0.00 0.00 Guaiacols/syringols 0.00 0.00 0.00 0.00 18.91 Straight-chain/branched alkanes

11.72 13.62 13.18 10.32 0.00

Unknowns 5.49 4.45 5.62 5.24 0.00 Total 100.00 100.00 100.00 100.00 100.00

And otred Composition of Feed1 products ( O1, O2, O3 and O4) after hydrocracking

HC – Feed and Product Composition UGent/FCh13/4L

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Richard J. French, Jim Stunkel, and Robert M. Baldwin Energy Fuels 2011, 25, 3266–327

Blending strategies for bio-oil in the petroleum refinery

Co-Processing Strategy : Mild hydrotreating (where moderate levels of deoxygenation take place) coupled with co-processing in a petroleum refinery

Co-Processing UGent/FCh13/4L

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Dist Col

Current Process development Efforts focus on Catalytic Hydroprocessing

FEEDS - Studies with Model Compounds More fundamental Chemistry questions - Studies with real Bio – Oils Estimation of process characteristics Scaleup Data – Feasibility - Sustainability

CATALYSTS - Traditional sulphided Catalysts

- Non- traditional precious metal catalysts

Much, but not all, of the required hydrogen can be produced from reforming of the gas by-products

Current Research UGent/FCh13/4L

8 March 2013

As real feeds are difficult to handle, model compounds representing the bio-oils’ most common or refractory molecules are examined.

MODEL COMPOUNDS

Aliphatic H/C Aromatic H/C

Carboxylic acids

Low MW ketones

Low MW aldehydes

Phenols (substituted or not)

Benzaldehydes Benzoketones

Primary Concern : Activity, Selectivity, Reaction Mechanism HDO of Functional Groups with Low MW molecules

Model Compounds UGent/FCh13/4L

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Phenolic C – O bond Is the most difficult to rupture

DeOxygenation Step – Catalyst Selectivity

Direct hydrogenolysis should be avoided - Aromatics

Hydrogenation route produces saturated HC

Weiyan Wang, Yunquan Tang, Hean Luo, Wenying Liu Reac Kinet Mech Cat, 2010, 101, 105-115

Studies – Model Compounds UGent/FCh13/4L

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V. N. Bui, D. Laurenti, P. Afanasiev, C. Geantet Applied Catalysis B: Environmental , 2011, 101, 239–245

General reaction scheme for GUA conversion with transition metal sulfide catalysts

DME, demethylation; DMO, demethoxylation; GUA, guaiacol; CAT, catechol; PHE, phenol; Me-CAT, methyl-catechol; Me-PHE, methyl-phenol.

Model Compound Guaiasol UGent/FCh13/4L

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Tentative mechanism for HDO of Benzofuran (BF)

M.C. Edelman, M.K. Maholland, R.M. Baldwin, S.W. Cowley, J. Catal. 111 (1988) 243.

BF

Model Compound Benzofuran UGent/FCh13/4L

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Possible reaction pathways for furfural conversion over Cu, Pd and Ni catalysts

N. Joshin, A. Lawal Chemical Engineering Science , 2012, 84, 761–771

Catalysts : 1% Pd/SiO4 5% Ni/SiO4

Selectivity of products from Furan Decarbonylation and ring opening (RO) (BAL+BOL+Butane) reactions

Model Compound : Furfural UGent/FCh13/4L

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Furfural (FAL)

Most Common Reactions during Hydrotreatment

DEMETHYLATION REACTION CH3

+H2 + CH4

METHYLATION REACTION OH

+ CH3-

OH

Me

DEHYDROXYLATION REACTION

OH

OCH3

OH

CH3

+ H2O

HDT Reactions 1 UGent/FCh13/4L

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HYDROGENOLYSIS REACTION

O + H2 OH

CH3

+ H2 + CH3-CH3

DEMETHOXYLATION REACTION

OH

OCH3

+ H2

OH

+ CH3OH

+ CH4 + H2O

OH

OH

HDT Reactions 2 UGent/FCh13/4L

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DECARBONYLATION REACTION

+ H2 OH

O

O

+ CO

AROMATIC RING OPENING REACTION

O

+ H2

O

H

KETO-ENOL TAUTOMERISM REACTION OH O

HTD Reactions 3 UGent/FCh13/4L

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CONDENSATION REACTION

H

OH+

CH3

+

OH

CH3

CH3

O CH3

HYDROGENATION REACTION

+ H2

HDT Reactions 4 UGent/FCh13/4L

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CATALYTIC MATERIALS TESTED

SUPPORTS

• SiO2 • γ-Al2O3 • ZSM-5(mesoporous/microporous) • HBEA • C • HZSM-5 • ZrO2 • CeO2-ZrO2 • SiO2-ZrO2-La2O3 • Amorphous borohydrites.

• Fe • Cu • Pd • Ni • Ga • Pt • Rh Bimetallic • CoMo • NiMo • RhPt • RhPd • PtPd • NiCu

ACTIVE METALS Monometallic

HDT Catalysts UGent/FCh13/4L

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LHSV : 0.1 – 40 h-1

Reaction Time : 1 – 20 h

Furfural Phenol

Benzaldehyde Acetophenone

Guaiacol o-m-p-cresol Dibenzofuran

Anisole Cyclohexanone Cyclohexanol

Model Compounds

Experimental Conditions

Reactor Type - Batch - Tubural - Continous

Pressure : 0.1 – 17 MPa Temperature : 170 – 400 0C

HDT Experiments UGent/FCh13/4L

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Catalyst amount used: 15-1500 mg

• Most of the research on Bio-Oils concerns the HDT of model compounds with one or more O-containing functional groups

• The most difficult to DO compounds are Phenols

• Catalysts with various selectivities have been tested and a spectrum of different molecules are produced from the various functional groups

• The design of the Bio-oil hydrotreaters and the strategy to reach the final biofuel strongly depend on Pyrolysis conditions and Biomass type

• The viable operation of an industrial process for biofuels production from biomass is strictly related to prediction of the performance of the Pyrolysis – Pretreatment system using various lignocellulosic raw materials

• Stabilization of the Bio-Oils after Pyrolysis is crucial for storage and further hydro-processing

• Co-feeding Bio-Oils and petroleum fractions is a promising way to reach the target of viably and sustainably produce biofuels from lignocellulosic mass in the short term

Conclusions UGent/FCh13/4L

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