Prof Johann Görgens

Department of Process EngineeringStellenbosch University

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Biorefineries for SustainabilityOf the Paper Industry

Drivers for Biorefineries1. Economic pressures of pulp production2. Global incentives for fuels/chemicals from

biomass (incentives, taxes, credits)3. Improved future profitability

Concepts1. Alternative fractionation methods2. Bio-energy through biological and

thermo-chemical processing3. Rigorous modelling of future

biorefineries

• North-America and Europe in decline, closures• New production capacity from South America and

East Asia• Pulp mill is already a biorefinery: Pulp and energy

• Commodities, but lack specialities• Economic value of potential products

• Biomaterials (optimal use of feedstock properties)• Biochemicals• Biofuels• Other forms of bio-energy

• Development adjacent to existing mills beneficial tofeedstock handling

Economics of Pulp Production

Biomass Refining OptionsBiomass Refining Options

Biomass Refining ExampleBiomass Refining Example

Bio

mas

s P

rod

uct

ion

, TS

&D

Ref

inin

g

TS

&D

What will we make

?

?

What inputs will be required?What will it cost?

Biomass RefiningBiomass Refining

1. Fractionation/pretreatment (“digestion”)Isolates chemical/structural components Lignocellulose made accessible for enzymatic hydrolysis

2. Biological conversionSugars as carriers of energy/carbon Conversion by pretreatment-hydrolysis or biocatalysis (enzymes, microbes)

3. Thermochemical conversionGas, bio-oil or charcoal as energy carriersConversion by thermal degradation or chemical synthesis

Conversion TechnologiesConversion Technologies

Lignocellulose FractionationLignocellulose Fractionation

� Novel pulping and matrix-opening technologies�Novel alkaline pulping, catalytic oxidation,

organosolv, steam explosion, ionic liquids, sub/supercritical extraction,

� Conversion of existing pulp mill into biorefinery, e.g. cellulosic ethanol

Fractionation – Hemis Pre-extractionFractionation – Hemis Pre-extraction� Long considered as entry-point to

biorefineries, but not practised commercially� Alkaline pre-extraction combined with

kraft/alkaline pulping� Leads to novel alkaline pulping methods, aimed at

maximising benefits from hemicellulose fraction

� One potential product: Xylan biopolymers/hydrogels� $2000/ton compare to heating value $50/ton

� Additives (pulp and paper, food & feed, textiles)� Coating (pharmacy, pulp and paper, textiles,

packaging)� Glue/gum (packaging, electrical, building) � Moisturiser (cosmetics, agriculture)� Tissue engineering (biomedical)� Encapsulation/implantation matrices (nano-

particles-nanotechnology, particle engineering)� Limitations of xylan biopolymers:

� Low degree of polymerisation, branching and substitution => High water solubility

Applications of BiopolymersApplications of Biopolymers

ControlXylan

hydrogelsXylan

hydrogels

Lignin

Adsorbents

Slow-release fertilizer/pestiside

Soil conditioner Humus formation

Dispersants

Phenolic precursors

Polymer substitution (resins, polyurethane)

Carbon fibre

Glue and binders

Fuels

SynfuelsElectricity

Biological ConversionBiological Conversion

� Sugars as energy carrier: Released from lignocellulose by pretreatment-hydrolysis

� Fermentation processes: Biogas, ethanol, butanol, organic acids, fatty acids and alcohols

� Sugar monomers for polymerization, similar to gasification-synthesis

Thermochemical ConversionThermochemical Conversion

� Combustion for heat, electricity� Pyrolysis for production of bio-oil and

charcoal� Chemicals, residual fuels and gasification

feedstocks, upgrading

� Gasification for electricity, ammonia, Fischer-Tropsch liquids, methanol, and dimethyl ether� Pure biomass gasification => use or sell� Biomass-coal co-gasification� Small-scale FT synthesis

Biomass Co-gasification with Coal for SynfuelsBiomass Co-gasification with Coal for Synfuels

� Impact of co-feeding on pyrolysis product

yields and quality

� Impact of co-feeding on pyrolysis kinetics

� Impact of co-feeding on char gasification

behaviour

Key objectives

0

5

10

15

20

25

30

South AfricaTotal 2008

PetroSA GTL2008

Sasol CTL2008

Sasol CTLFuture

Brazil EtOH2008

USA EtOH2008

Mill

ions

of m

etric

tons

Biomass use in CTL and GTL plants in South AfricaBiomass use in CTL and GTL plants in South Africa

Biomass use in CTL and GTL plants in South AfricaBiomass use in CTL and GTL plants in South Africa

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

USA cellulosic EtOH2010

CTL+GTL 10%biomass 2008

CTL+GTL 10%biomass future

New CTL plants 10%biomass

Mill

ions

of m

etric

tons

Biological and Thermochemical Process routesBiological and Thermochemical Process routes

Biological Thermochemical

Co-fermentation Pyrolysis

Fast Pyrolysis

Gasification

Fischer-Tropsch Synthesis

Pyrolysis OilElectricity*

Vacuum Pyrolysis

Pyrolysis OilChar*

Electricity*

FT DieselFT Petroleum

Electricity*

Bio-ethanolElectricity*

* Byproduct

-5%

15%

35%

55%

75%

95%

ETOH-LHW 5%

ETOH-DA 10%

ETOH-DA 35%

ETOH-SE 50%

Fast Pyrolysis

Vacuum Pyrolysis

FT-BAG (EG

1)

FT-BAG (EG

1 shift)

FT-BAG (EG

2)

FT (Kreutz and Larson)

FT-FPS (EG

2)

FT-VPS (EG

2)Energy conversion

[MW

product/

MW

input]

Liquid fuel Char Surplus electricity

Energy Conversion EfficiencyEnergy Conversion Efficiency

$0

$5

$10

$15

$20

$25

$30

$35

$40

$45

Fast Pyrolysis, 145MW

Fast Pyrolysis, 600MW

Vacuum

Pyrolysis, 145MW

Vacuum

Pyrolysis, 600MW

ETOH-35% dilute acid, 145MW

ETOH-35% dilute acid, 600MW

ETOH-steam explosion, 145MW

ETOH-steam explosion, 600MW

FT-bag (EG1), 145MW

FT-bag (EG1), 600MW

FT-bag (EG1-shift), 600 MW

FT-bag (EG2), 600 MW

FT-fps (EG1), 600MW

FT-vps (EG1), 600MW

Liquid fuel production cost [$/GJ]

$0

$20

$40

$60

$80

$100

$120

$140

$160

Breakeven Oil Price

[$/barrel crude oil]

Economic ComparisonEconomic Comparison

0%

10%

20%

30%

40%

50%

60%

28 35 42 49 56 63 70 77 84 91 98 105

112

119

Crude Oil Price [$/barrel]

Internal rate of return

Fast Pyrolysis Bioethanol (steam explosion) Fischer-Tropsch (G1)

Char high

Char low

Electricity high

Electricity low

0%

10%

20%

30%

40%

50%

60%

28 35 42 49 56 63 70 77 84 91 98 105

112

119

Crude Oil Price [$/barrel]

Internal rate of return

Fast Pyrolysis Bioethanol (steam explosion) Fischer-Tropsch (G1)

Char high

Char low

Electricity high

Electricity low

0%

10%

20%

30%

40%

50%

60%

28 35 42 49 56 63 70 77 84 91 98 105

112

119

Crude Oil Price [$/barrel]

Internal rate of return

Fast Pyrolysis Bioethanol (steam explosion) Fischer-Tropsch (G1)

Char high

Char low

Electricity high

Electricity low

Char high

Char low

Electricity high

Electricity low

Sensitivity AnalysisSensitivity Analysis

Stochastic Economic ModelsStochastic Economic Models

Biological vs. Thermochemical ConversionBiological vs. Thermochemical Conversion� Process integration offers advantages to

both� Feedstock handling, energy utilities, unit

operations� Enhance economic returns by integration of

biorefinery processes� Site-specific integration will dictate selection

� Integration based on feedstock components�Carbohydrates for biological and lignin for

thermochemical

Heat andElectricity for process

Sucrose 50%

HMF

(hydrolysis)

Mannitol(C/F)

Sorbitol (C)

Biofuels (F)

Cellulases

Glucose

Lactic acid (F)

Levulinic acid (hydrolysis)

Furfural (hydrolysis)

Xylitol/Arabinitol (C/F)

Gluconic acid (F)

Succinic acid (F)

Other

products (F)Citric acid (F)

Xylose

Hemicellulases

Arabinose

F: FermentationC: Chemical catalysis

Lignin

25%

Hemicellu

lose 25%

Cellulose

40%

Pretreatment and fractionation

Glucose 4% With

invertase(29%)

Fructose 4%With

invertase(29%)

Bagasse Molasses

Biodegradable polymers

Food additives Biodegradable

solventsFuels and fuel

additivesBuilding block

chemicals

Integrated BiorefineryIntegrated Biorefinery

Post-BiologicalProcessing

39%Residues

Power

Bioprocess(steam, power) 14%

Power(17%)

0.75% power demand displaced for every1 % transport fuel demand displaced (US)

Large baseload power contribution,compliments intermittent sources

Processing Residues from Biological Processing Offers Lots of Value

Internal cogeneration - most energy for biological processing is from waste heat accompanying power and/or FT fuel production

Maturation of biological conversion --> much larger opportunities

Post-BiologicalProcessing

39%Residues

Bioprocess(steam, power)

FT fuels(21%)

Fischer-Tropsch fuels (diesel, gasoline)

14%

Slate of fuels including bioethanol, FT diesel, FT gasoline (or added ethanol)

E90 entirely from renewables

Current

BiologicalProcessing

Post-BiologicalProcessing

100%

39%

54%

Mature

BiologicalProcessing

Post-BiologicalProcessing

100%

39%

54%

ConclusionsConclusions� Drivers for biorefineries differ between parts of

the world�Future profitability, environmental

opportunities� Fractionation

� Isolate high value biomaterials prior to destruction

� Biological and thermochemical processing� Reduce lignocellulose to preferred energy carrier� Major impact on product spread

� Rigorous biorefinery modelling and scenario building required� Looking into the glass ball of future markets for

materials, chemicals, fuels