Günther Bochmann – IFA-Tulln Pre-treatment of feedstock for enhanced biogas production Günther Bochmann Lucy Montgomery
Günther Bochmann – IFA-Tulln
Pre-treatment of feedstock for enhanced
biogas production
Günther Bochmann
Lucy Montgomery
Günther Bochmann – IFA-Tulln
IEA Task 37
Work programme 2013-2015
Work
Knowledge exchange
Technical brochures
Success stories
Studies
Australia, Austria, Brazil, Denmark, European Commission, Finland,
France, Germany, Ireland, Norway, South Korea, Sweden,
Switzerland, The Netherlands, United Kingdom
www.iea-biogas.net2
Günther Bochmann – IFA-Tulln
Task 37
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Günther Bochmann – IFA-Tulln
Recently published brochures
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Günther Bochmann – IFA-Tulln
Aim of pretreatment technologies
Reduction of specific production costs
Substrate costs (%)
Investment costs (%)
Operation costs (%)
Realisation by
Increasing the biogas yield
Inceasing degradation rate
Increasing the plant efficiency
Reduction of operation costs
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Günther Bochmann – IFA-Tulln
Substrates
Kohlenhydrate
Proteine
Fette
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Günther Bochmann – IFA-Tulln
Carbon hydrates
Starch
Cellulose
Hemicellulose
Lignin
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OHHOCH2
O
CH3O
HOCH2
C CH2OH
O
O
HOCH2
CH3O O
OCH3
OH
CH2OHO
OCH3
O
O
O
CH3O
O
HOCH2
O
OCH3
OH
O
O
CH2OH
O
H2C
OH
O(C5H10O6)nH
CH2OHO
OCH3
O
OCH3CHO-CH=CH
CH2OH
O
OCH3
OCH3
O
CH3O
O
O
CH3
OCH3
OH
CH2
O
Günther Bochmann – IFA-Tulln
Impact pre-treatment
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Günther Bochmann – IFA-Tulln
Impact pretreatment on AD
Higher gas production can occur
HRT
Specific retention time in digester
Digester system need to be included
Viscosity
Substrate charateristics
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0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2
C
BGP A
BGP B
Günther Bochmann – IFA-Tulln
Pre-treatment technologies
Physical Mechanical Thermal Ultra sound Electrocinetical
Desintegration
Chemical Alcaline Acidic
Biological Microbiological Enzymatical
Combined
processes
Steam Explosion Extrusion Thermo-chemical
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Günther Bochmann – IFA-Tulln
Mechanical
Principle
Mechanical crushing
e.g. cutterbars
Advantage
Relatively low invesment costs
Relatively low energy demand
Disadvantage
Interfering materials reduce life
time of unit significantly
Mode of action
Increasing of specific surfaceQuelle: IKTS Frauenhofer
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Günther Bochmann – IFA-Tulln
Thermal
Principle
Thermal pretreatment leads to
disintegration of hard degradable
substances
Advantage
Higher gas yield
Exclusively heat demand
Disadvantage
High investment costs
Production of inhibiting substances
Mode of action
Solving of hemicellulose and swelling of
biomassQuelle: Dr. Franke ATZ/D
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Günther Bochmann – IFA-Tulln
Thermal processes
Non-enzymatic browning reaction
Maillard reaction
3 step process
End products melanoidines
N-catalysed process
pH-value essential for pathway
Bacteriostatic effect of intermediate products
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Günther Bochmann – IFA-Tulln
Steam explosion
Principle
Heating and abrupt decompression
Advantage
Higher gas yield
Only thermal energy
Disadvantage
Higher investment costs
Formation of inhibiting substances
Mode of action
Rupture cell structuresQuelle: Boku
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Günther Bochmann – IFA-Tulln
Thermo-mechanical
Principle
Extruders crush biomass
Advantage
Degradation rate
Relatively low investment costs
Low energy demand
Disadvantage
Interfering materials reduce life
time of unit significantly
Mode of action
Increasing of specific surface
Quelle: IFA Tulln
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Günther Bochmann – IFA-Tulln
Chemical
Principle
Addition of lye or acid in an additional pre-
treatment step
Advantage
Higher gas yield
Faster degradation
Disadvantage
Operation costs
Production of inhibiting products
Mode of action
Solving of lignocellulose complex
Quelle: enbasys
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Günther Bochmann – IFA-Tulln
Thermo-chemical
Principle
Support of chemicals through heat
Advantage
Higher gas yield
Faster degradation
Disadvantage
Operation costs
Production of inhibiting products
Mode of action
Solving of lignocellulose complex0
100
200
300
400
500
600
700
800
900
1000
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43
Bio
ga
sa
us
be
ute
[m
³/k
g o
TS
]
Zeit [d]
Ohne Behandlung
Thermochemischer Aufschluss 1
Thermochemischer Aufschluss 2
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Günther Bochmann – IFA-Tulln
Microbiological
Principle
Additional digester
Advantage
Faster degradation
Higher methane concentration
Disadvantage
No higher gas yields to be
expected
Mode of actionReduced pH enables enzymes
to work in their optimum Quelle: AAT
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Günther Bochmann – IFA-Tulln
Preacidification
Or dark fermentation
Formation of VFA and alcohols
H2 and CO2
pH value important
Increased enymatic activity
Recirculation
Microbiology
Increasing buffer capacity
H2S formation
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Günther Bochmann – IFA-Tulln
Ultra sound
Principle
Ultra sound into digester
Advantage
Low energy demand
Low investment costs
Disadvantage
No direct degradation of biomass
Mode of actionUS frequences lead to cavity or the
formation of gas bubbles and their
implosionQuelle: ULTRWAVES /D
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Günther Bochmann – IFA-Tulln
Electrocinetical disintegration
Principle
Addition of high voltage impulses
Advantage
Low energy demand
Low investment costs
Disadvantage
No direct degradation of biomass
Mode of actionElectrical field destroyes ionic bounding of
cell walls by changing the chargeQuelle: ATRES Group/D
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Günther Bochmann – IFA-Tulln
Overview influences of the pretreatment
technologies
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Günther Bochmann – IFA-Tulln
Summary/conclusion
Many tests have no reliable data
2 points for BMP tests
Sufficient duration
Pre-treatment technologies specific to substrate
Pre-treatment technologies specific to plant
Awareness of investement and operation costs
Energy balance
Awareness of higher gas yield
Additional effects of pre-treatment technologies
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Günther Bochmann – IFA-Tulln
Thank you
Günther Bochmann
IFA-Tulln Universität für Bodenkultur
Institut für Umweltbiotechnologie
Bioenergy 2020+
Konrad Lorenz Strasse 20
3430 Tulln
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