Conversion of biomass to ethanol – the

Inbicon and Biogasol processes

Senior research scientist, ph.d.

Anne-Belinda Bjerre

With special attention to

pretreatment technology

Global bioethanol production (Fischer

2007)

Production capacity of fuel ethanol 2006

Global production = 35 million ton

15 mill ton

15 mill ton

3 mill ton

3 mill ton

Brazil

USA

EU

Other

Nearly all is 1st generation bioethanol

History of bio-ethanol production in USA

Ethanol Production in US

0

2000

4000

6000

8000

10000

12000

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

Millo

n o

f G

allo

ns p

er

Year

Estimation of USA’s bioethanol needs

Target in 2022: 36 billion gallons/year

Todays situation:

Corn ethanol equals 15 billion gallons/year

21 billion gallons/year will come from cellulosic ethanol and

other advanced biofuels.

DK 2005

Gasolin: 2,1 mill. m3

Diesel: 2,3 mill. m3

Transport sector

25% of total

CO2 emmision

EU-target – substitution

gasolin with med biofuel:

2010: 5,75 %

2020: 10 %

Biofuel targets for selected major economies

(status 2008)

Country (group) Blending target

or mandate

Quantity or

share

Target year

Brazil M 25% ethanol

5% biodiesel

2007

2013

Canada M 5% ethanol

2% biodiesel

2010

2012

China T 15% fuel for

transportation

2020

EU-27 T 10% of

transportation fuel

2020

India M 10% ethanol

5% biodiesel

2008

2012

Japan T 6 billion litres 2020

USA* M 134 billion litres =

36 billion gallons

2022

*current gasolin market in USA : 140 billion gallons/year

Choice of biomass resources for energy

0

20

40

60

80

100

120

MtO

E

2003 2010 2020 2030

Year

Wood

Waste

Crops

Source: http://dataservice.eea.europa.eu

Wheat

Maize

straw (~ 45%)

grain (~ 55%)

grain (~ 34%)

corn stover (~ 60%)

others (~ 6%)

starch content: ~ 65 %

cellulose content: ~40 %

starch content: ~ 65 %

cellulose content: ~ 40 %

From 2006-2007 the price of

maize grain is dobbelt

1/3 af world maize grain

production is used for

bioethanol production

2. generation bioethanol - definition

= bioethanol produced biologically

from plant residues or other

lignocellulosic materials:

straw (wheat, rye, barley, maize)

wood chips

grasses

household waste

paper waste

Bioethanol

1. generation Bioethanol:

Substrate: Sugar (sucrose) from sugarcane and starch from corn or wheat.

Milling and cooking before enzymatic hydrolysis.

Optimised, commercial enzymes available

2. generation Bioethanol:

Substrate: Lignocellulosic materials (straw, corn stover, wood, waste)

Chemical/physical pretreatment necessary to facilitate enzymatic hydrolysis.

Commercial enzymes are now available

2.generation bioethanol reduces CO2 emmision with 90 -100% (WELL-to-WHEELS Report, EU commition 2007)

Bioethanol potentials

Raw material

Ethanol yield

EtOH

kg/t ts

Yield

hkg/ha

EtOH

tons/ha

Wheat (grain) 400 100 4,0

Wheat straw 250 70 1,8

Corn/maize (grain) 410 70 2,9

Corn stover 250 60 1,5

Corn silage 390 140 5,5

Clover grass 300 560 3,0

Sugar beet 480 600 7,2

Household waste 230 - -

Hauggaard-Nielsen et al., 2006

Fotosyntesen

H20 CO2

glucan

enzymes

glucose

yeast

ethanol + C02

C6 bioethanol

From cellulose to glucose and ethanol

Pretreatment

Break up of structure of cell wall

Delignification

Flexible fractionation of

carbohydrates

Enzymatic hydrolysis

Cellulases

Fermentation

yeasts

S. cerevisiae

K. marxianus

6 12 5 2 6 12 6( )nC H O nH O nC H O

1g glucose 0.51 g ethanol

Composition of straw. Ex. rape straw

% wt.

29.017.6

19.1

2.3

5.6

Cellulose

Hemi-cellulose

Lignin

Ash

Extractives

Structure of lignocellulose

Lignocellulose

Cellulose C6 sukre

Lignin

Hemicellulose C5 sukre

Plant cell wall contains sugars and lignin

Cellulose

Hemicellulose

Lignin

Chemical composition of plant cell wall

Pretreatment of lignocellulose

Cellulose

Lignin

Hemi-cellulose

Cellulose

Lignin

Hemi-cellulose

Making the sugar polymers assecible for enzymes

2. generation Bioethanol production

Pretreatment

Hemicellulose

Lignin

Cellulose

Distillation

Enzymes Yeast

Enzymes

C5

Micro-organism

Fermentation Hydrolysis

Bio-Ethanol C6

Hydrolysis Fermentation

Fermentation of pretreated clover grass with Mucor indicus

Time (h)

0 20 40 60

Concentr

ation (

g/l)

0

2

4

6

8

10

12

14

16

18

0 20 40 60 80 100 120 140

Aerobic Oxygen limited Glucose XyloseEthanol

Pretreatment of plant biomass for ethanol

production

Well known methods

Steam explosion

Wet oxidation

Hydrothermal treatment (hot water extraction)

organosolv (removal of lignin by ethanol extraction)

Future pretreatment methods Micro wave assisted pretreatment

plasma pretreatment at low temperature

ultrasound

IBUS – from lab to demo

Risø 10 kg straw/h

Fyns-CHP 100 kg straw/h

Skærbæk-CHP 1000 kg straw/h

Risø < 1kg/h

Kalundborg 4000 kg straw/h

Two Danish commercialized processes for 2nd generation

bioethanol production

IBUS BioGasol

Developed new enzymes

Novozymes

Bio-ethanol from straw (2nd generation)

Sugar Lignin

Straw

Cellulose/

hemicellulose

Yeast

Ethanol

Fermentation

When the sugar monomers are released they can be fermented into ethanol by e.g. the yeast

Saccharomyces cerevisiae (baker’s yeast). S. cerevisiae is very robust and can efficiently convert e.g.

glucose and mannose into ethanol during anaerobic conditions. However, other sugar monomers such as

xylose (from hemicellulose) are not converted by this yeast. The residues after separation of the ethanol

can be brought back to the soil and used as a fertilizer.

Poster made by:

Anneli Petersson

Tomas Fernqvist

Production of

raw material

Straw is produced as a surplus from farming in many countries

and can be used as raw material for bio-ethanol production.

Straw is a lignocellulosic material and is built up by mainly three

components: cellulose, hemicellulose and lignin. Cellulose and

hemicellulose are polymers of sugar monomers which can be

converted into ethanol. Lignin is a complex polymer that

function as a glue that makes lignocellulosic materials such a

solid structure.

Enzymatic

hydrolysis

In the hydrolysis step the pretreated material is cut into sugar

monomers by enzymes. Enzymes work as catalysts that cut the

hemicellulose and cellulose into smaller sugar polymers and

then into monomers such as glucose.

During combustion of ethanol in a car engine mainly carbon dioxide

and water is formed. The carbon dioxide released can be taken up

by growing straw.

Combustion

Ethanol

CO2

Straw

Pretreatment

The first step in making the sugar monomers available for conversion to ethanol is the pretreatment. The

pretreatment is done to open up the solid structure of the straw and make the material available for enzymatic

hydrolysis. This can be done by exposing the cut straw to high temperature and pressure. In the pretreatment

step straw and water is mixed and exposed to high temperature and pressure. During the pretreatment the

most easily hydrolysed materials, such as part of the hemicellulose, ends up in the liquid fraction. The more

stabile components, such as the cellulose remains in the solid fraction.

Bioethanol co-produced with biogas

(Biogasol) Wet Oxidation

In: Wheat Straw

Water

SSF Fermentation

In: Enzyme, Yeast

Out: Ethanol

Xylose Fermentation

Out: Ethanol

Anaerobic Treatment

In: Manure

Out: Biogas

Wet oxidation for bioethanol production

Pre-treatment method well suited for

agriculture crops such as wheat straw and

corn stover

-R- + O2 products + CO2 + H2O + energy

Exothermic reaction:

High (moderate) temperature 195oC

oxygen (12 bars)

Reaction time 10-15 minutes

Wet oxidation

1 kg wheat straw 0.5 kg solids

Filter cake (solids):

70-75% Cellulose

5-10 % Hemicellulose

5-10 % Lignin

0.3 % Ash

Liquid phase:

35-45% Sugars

12-26 % Carboxylic acids

0.3-1 % Furans

0.5-1.8 % Phenols

NH4,P, K, minerals

in % of total organic carbon

0

10

20

30

40

50

60

70

80

wet oxidation raw material

24 h

48 h

72 h

SSF of pre-treated wheat straw :

% cellulose converted to ethanol

Conditions: 10% filter cake, enzyme loading 20 FPU/g DM

Enzyme hydrolysis of WO-pretreated rape straw

0

20

40

60

80

100

195:10:Air 195:15:WO 200:5:WO 205:3:WO 210:2:WO

Yie

ld o

f si

mp

le s

ugars

(%

of

glu

co

se p

ote

nti

al

of

pre

treate

d m

ate

rial)

After 24-hours enzyme hydrolysis to simple sugars

Cellobiose yield

Glucose yield

Air: Ambient air pressure

WO: Oxygen gas 12 bar

Enzyme: Cellubrix

Recovery of main components of rape straw

after WO pretreatment

0

20

40

60

80

100

A B C D ECellu

lose

reco

very

(%

of

raw

mate

rial)

Cellulose

Soluble cellulose

Insoluble cellulose

0

20

40

60

80

100

A B C D E

C5 r

eco

very

(%

of

raw

mate

rial)

Hemicellulose

Free C5 sugars

Soluble oligomeric

hemicellulose

Insoluble

hemicellulose

0

20

40

60

80

100

A B C D E

Reco

very

of

solid

lig

nin

(%

of

raw

mate

rial)

Lignin

Fermentation time (h)

0 20 40 60 80 100 120 140 160 180

Eth

ano

l pro

duction (

% o

f th

eore

tica

l)

0

20

40

60

80

100

120

140

untreated

195°C, 15min

195°C, 15min, lactic acid & acetic acid

195°C, 15min, lactic acid

195°C, 15min, acetic acid

SSF of untreated/treated corn stover

Compared with lactic

acid or lactic/acetic

acid, pretreatment

with acetic acid was

more helpful in

promoting the

ethanol production

Effect of acetic acid and lactic acid during

pretreatment

Co-production of bioethanol with electricity

water

enzymes

yeast

C5-sugars:

fodder

lignin

ethanol

Fertilizer

Inbicon

IBUS 1000

PP1 PP2

PP3

Kraft-

varmeværk

Separation

Ethanol destillation

straw

cutting

Reactor 1

(80 °C)

Reactor 2

(160-200 °C)

Reactor 3

(190-230 °C)

water

Fiber fraction

(cellulose

+lignin)

Enzymes

yeast

Fermentation

Ethanol

Hydrolysate

(hemicellulose)

solid fuel (lignin)

heat/steam El

Hydrolyse og

fermentation Microorganisme

CO2 CO2

Export of

heat and electricity

Fodder

Production price calculated for 3 scenaries

0

1

2

3

4

5

6

7

8

9

10

11

20 40 60 80 100

Cellulose konverteringsratio (%)

Eth

an

ol

pri

s i

kr/

L

Case 1

Case 2

Case 3

Case 1:

only C6

fermentation on

green field

Case 2:

C6 fermentation

with co-production

of heat and power

Case 3: C6 + C5

fermentation

with co-

production of

heat and power

1.8 mill tons surplus straw in Denmark

900.000 tons straw 200.000 tons ethanol

= one year consumption at 10% addition to gasoline

1-2 factories

Perspectives

Problems to be solved to reduce cost

How can we avoid high pressure and high temperature?

How can we increase the dry matter during pretreatment?

Hypothesis:

1. Wet oxidation can be carried out by plasma generated ozone

at ambient temperatur and high dry matter biomass with an

effective oxidation (partial removal) of lignin and enhanced

enzymatic hydrolysis of pretreated material

1. Silage pretreatment can be used as storage and pretreatment of

green biomass with enhanced enzymatic convertibility

Plasma is defined as the fourth state of matter

Plasma is the most energy rich state of matter

A plasma is an ionized gas

slide adapted from Frank Leipold

What is a Plasma ?

Low Temperature Plasma consists of: Electrons, Ions, Radicals and Molecules

Dry atmospheric air is used -> consits of N2, O2 and Ar

Main reaction for our application:

3 O2 2 O3

O2 + e- -> O + O

O2 + O -> O3

slide adapted from Frank Leipold

Pretreatment Reactor

Layer

Bottom

O3 out

O3 in

Lid

Sieve: (Ø: 30 cm, mash size: 0,2mm)

Wheat straw (1mm) after 7 hours ozonisation.

Wheat straw (45% DM, 1mm) treated in multi-layer-reactor by ozonisation.

Plasma pretreatment of wheat straw

Main Results: Plasma Assisted Pretreatment

• Relatively fast method (0.5-2 h) established

• Pretreatment at high dry matter concentration of 45% - 60% possible

• Full recovery of carbohydrates

• Glucan conversion ~60% and xylan conversion ~75%

Ensiling – a wet-storage and a biological

pretreatment method

Ensiling (silage pretreatment): humid green biomass wrapped in

plastic, used as a wet-storage and low-cost alternative to traditional

pretreatment techniques for bioethanol production.

The silage process: lactic acid bacteria fermenting free sugars to

lactic acid, lowing pH, thus inhibiting other microbes to degrade the

polysaccharides.

NB! at the same time, partly disrupting the lignocellulosic structure

making it accessible for controlled enzyme attack.

Ensiling – a wet-storage and a biological pretreatment

method

51,4

28,631,8

0

20

40

60

80

100

Fresh maize Fresh rye Fresh clover

Co

nve

rte

d b

y ce

llula

se [

%]

Enzymatic cellulose convertibility of ensiled biomass in acetate buffer (enzyme loading 30 FPU) for 24

hours presented in % of cellulose converted to glucose of, ensiled crops (A) and hydrothermal

pretreated ensiled crops (B)

54,054,0

50,9

0

20

40

60

80

100

Maize silage Rye silage Clover silage

Co

nve

rte

d b

y ce

llula

se [

%]

A B

Conclusions

Denmark has the knowledge and knowhow for establishing 2. generation bioethanol plants in a biorefinery concept. World largest demoplant is now built in Kalundborg (opening day 18th November 2009).

2. generations bioethanol should be co-produced with

feed

electricity (heat and power)

biogas

fertilizer

and /or value added products

Ozone pretreatment is a high tech promissing pretreatment method for full recovery of carbohydrates at high dy matte, low temperature and low pressure

Silage treatment is a low tech storage and pretreatment method for green crops such as grasses and maize.

IEA’s ”Strategy Plan 2010-2016” for

member countries

Security of energy supply

Reduce dependency of fossil fuel

Reduce green house gas emission

Develop sustainable, non-food biomass resources for

bioenergy applications

Large scale development and new technologies for bioenergy

production

Support energy policy development

Promoting IEA bodies and their global energy and

environmental strategies