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