Overview of Biogas Technology and Legislative Framework for Biogas Utilization … · ·...
Transcript of Overview of Biogas Technology and Legislative Framework for Biogas Utilization … · ·...
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1 German Biogas Association
Overview of Biogas Technology and Legislative Framework for Biogas Utilization in Europe
MSc. Felipe Kaiser
Bavarian Research Center of AgricultureInstitute of Agricultural Engineering, Farm Buildings
and Environmental TechnologyGermany
BIOENERGY FOR SUSTAINABLE RURAL DEVELOPMENT
LAMNET PROJECT WORKSHOPViña del Mar - November 2004
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• Biochemical Process of Biogas Production• Technical Systems• Peculiarities of Framework• Biogas Utilization in Germany• Environmental Effects • Conclusions
Structure
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Biochemical Process of Biogas Production
I Hydrolysis
II Fermentative bacteria
III Acetogenic bacteria
IV Methanogens
Biogenous polymers(proteins, carbohydrates)
Monomers(sugars, amino acids, peptides)
Hydrolytic enzymes
(modified after http://www.uasb.org)
AcetateH2 + CO2
Propionate, butyrateII II
II
III III
III
CH4 + CO2
IV IV
One-stage process
Two-stage process:
Separation ofhydrolyticandmethanogenicstage
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Higher the T°the faster up to
55°C
~ 6 Microaerophil -
4 – 6 Strict anaerobic
-
Mesophil~35°C
Tolerance range6,8 – 7,5
Strictanaerobic
Minimal–330mV
Hydrolysis
AcidogenicPhase
AcetogenicPhase
Methanogenesis
Steps Temperature pH Air environment
Redox-potential
Thermophil~55°C
Biochemical Process of Biogas Production
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Substrate Reaction
Carbohydratef.e.: Glucose
C6H12O6 → 3 CO2 + 3 CH450 % : 50 %
Fatf.e.:Palmitic acid
2 C6H32O2 + 14 H2O → 9 CO2 + 23 CH428 % : 72 %
Protein(average)
2 C13H25O7N3S + 12 H2O → 13 CO2 + 13 CH4 + 6 NH3 + 2 H2S38 % : 38 % : 18 % : 6 %
Biochemical Process of Biogas Production
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Kinetics of Biogas Production
Digester-specific biogas production [m3/m3*d]
Biogas yield [m3/mass of substrate]
Rel
ativ
e in
tens
ity [%
]
0 5 10 15 20 3025Hydraulic retention time [days]
0
40
60
80
100
20
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PROCESS DESIGN
HUMIDITY OF SUBSTRATE
WET
DRY
or
STOCK FLOW
CONTINOUS
DISCONTIOUSor
RANGE OF TEMPERATURE
MESOPHILIC
THEROMPHILICor
STAGES OF FERMENTATION
SINGLE-STAGE
MULTIPLE-STAGEor
Process Design Characterisation
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Technical Systems: General Objectives
• Maintain a stable digestion process• Maintain continuous methane production• Accomplish high methane yields by means of:
– Optimized feedstock mixture– Appropriate pre-treatment– Optimized digester operation
• Keep building costs reasonably low
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Technical Systems: Process Overview
Feedstocks
Crushing
Screening
Hygienization
Pre-treatment
Biogas treatment and utilization
Anaerobic digestion
Digestate storage
Land spreading
Advanced treatment
Feeding into gas distribution systemUse as fuel
Desulfurization
Dewatering
Heat and power generation
Feeding into grid
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Harmless Pathogens Contraries Pollutants
Feedstocks: Origins and Potential Risks
VegetablesBrewer grainsBeet cuttingsStarch
Spoiled foodstuffs
Industrial wastes
Spoiled foodstuffs
Wastes from vegetable oil production
Maize, grain, grass, beets, etc.
Renewable primary products Agricultural wastes
ManuresSugar beet leafsStraw
Slaughterhouse wastes
Rumen contentsContents of grease-skimming tanksStomach/gut contentsBlood meal
(Skimmed grease)
Others
Canteen kitchen wastes
Canteen kitchen wastesHousehold wastes
Cut grassGreens
Municipal wastes
Biowaste Sewage sludgeBiowasteRoadside grass
Biowaste
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Feedstocks: Biogas Yields
0
200
400
600
800
1000
1200
1400
1600
Rin
derm
i st
Rin
der g
ü lle
Stro
hal
l g.
Ger
sten
s tro
h
Sc h
wei
nem
agen
inha
lt
Mel
a sse
Kar
toffe
l di c
ksc h
lem
pe
Hüh
ner g
ü lle
Sch
we i
n egü
lle
L aub
Pa n
sen i
n hal
t
We i
zens
troh
Rüb
enbl
att
Bio
mü l
l
Gem
üse a
bfä l
le
Kl e
e
Ras
ensc
h nitt
Ma i
ssil a
ge
Gra
ssil a
ge
Gr a
s
Bie
rt re b
er
Pfe
r dem
ist (
frisc
h)
Rüb
enpü
l pe
Z uck
errü
b ens
ilage
CC
M
Fett a
bsc h
eide
rfett
Flot
a tf e
tt
Cat
tle m
anur
eLi
quid
cat
tle m
anur
eSt
raw
Bar
ley
stra
wPi
gs‘ s
tom
ach
cont
ents
Mol
asse
sPo
tato
e m
ash
Chi
cken
man
ure
Liqu
id p
ig m
anur
eLe
afs
Rum
en c
onte
nts
Whe
at s
traw
Suga
r bee
t lea
fsB
iow
aste
Vege
tabl
esC
love
rC
ut g
rass
Mai
ze s
ilage
Gra
ss s
ilage
Gra
ssB
rew
er g
rain
sH
orse
man
ure
Bee
t pul
pSu
gar b
eet s
ilage
Cor
n-co
b-m
ixSk
imm
ed g
reas
eFl
oata
tion
grea
se
Bio
gas
yiel
d [L
/kg
dry
orga
nic
mat
ter]
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Feedstocks: General Requirements
• Have to be biologically degradable under anaerobic conditions (e.g., no woody material)
• Suspension should have a dry matter content betweenapproximately 2 and 15 % to be pumped
• Feedstocks with more than 15 % dry matter content need special input systems
• Should have a balanced nutrient content, at least in mixture
• Must have no bactericidal properties
• Should contain no persistant pollutants (organic compounds,heavy metals, antibiotics) or pathogens in view of agricultural use of digestate
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Technical Systems: Process Overview
Feedstocks
Crushing
Screening
Hygienization
Pre-treatment
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Digester
Extern Tank
DM = max. 13%
Pre-treatment: Input Systems
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Extern Tank
System:The Feedstock is mixed with manure and pumped to the digester.
Pre-treatment: Input Systems
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Digester
Extern Tank
DM = max. 13%
?Maize silage = 35 % DMGrass silage = 40 % DMManure = 35 % DMStraw = 90 % DM
Pre-treatment: Input Systems
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Re-injection System
System:The Feedstock is washed with digested material and pumped to the digester.
Pre-treatment: Input Systems
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Mix Tank
System:The Feedstock is mechanically mixed, cut and pressured into the digester.
Pre-treatment: Input Systems
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Pre-treatment: Input Systems
Mix Tank
System:
The Feedstock is mechanically mixed and pushed into the digester.
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Pre-treatment: Input Systems
Mix Tank
System:
The Feedstock is mechanically mixed and pushed into the digester.
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Technical Systems: Process Overview
Feedstocks
Crushing
Screening
Hygienization
Pre-treatment Anaerobic digestion
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Technical Systems: Digester Designs
Cylindrical stirred tanksMaterial: Concrete (or steel).
Heat insulation: Typically foamed plastic.
Covering: Sheet metal or wood.
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Technical Systems: Digester Designs
Biogas storage in the digesterunder a stretch hood.
Single-layer
With additionalsoft cover
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Technical Systems: Digester Designs
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Technical Systems: Digester Designs
Horizontal tubular digesters.Material: steel (or concrete).
Multi-beam paddle mixers with longitudinal axle that can be heated.
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Technical Systems: Digester Designs
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• Minimization of process energy need• Avoid temperature losses• Avoid temperature differences
Materials:
Floor and roof (concrete roof): Styropor
Wall and roof (plastic cover):Polystyrol
Technical Systems: Isolations
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Warming the digesting substrate at optimal temperature.
Compensation of the lost temperature.
Technical Systems: Heating
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• Homogenization• Estimulate gas exit• Avoid sink material• Avoid floating material, crushing of crust
Technical Systems: Mixing
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BHKW (37 kW)
Wärmepuffer
Perkolattank
Kondensat-abscheider
Biofilter
Pumpensumpf
Bürogebäude
Gas-speicher
Technical Systems: Dry Fermentation
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Technical Systems: Dry Fermentation
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Technical Systems: Process Overview
Feedstocks
Crushing
Screening
Hygienization
Pre-treatment
Biogas treatment and utilization
Anaerobic digestion
Desulfurization
Dewatering
Heat and power generation
Feeding into grid
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• Dewatering
12 %
4 %
15 %
61 %
Long pipes for condensation
Cooling
Mechanical dewatering
Condensation
• Desulfurisation
7 % 2 %
91 % Air
Iron-Cloride
Iron
Technical Systems: Biogas Treatment and Utilization
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Technical Systems: Biogas Treatment and Utilization
Combined heat and power generation:
• Pilot-injection engine• Gas engine
20 – 20.000 ppm~ 40 g/m3 (saturated)
0 Vol.-%25 - 40 Vol.-%55 - 70 Vol.-%
Raw gas
0 – 200 ppmHydrogen sulfide (H2S)10 – 12 g/m3Water (H2O)0 - 1 Vol.-%Oxygen (O2)
25 - 45 Vol.-%Carbon dioxide (CO2)55 - 75 Vol.-%Methane (CH4)Treated gas
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Pilot-injection engine
90 % Biogas10 % Diesel
30 – 40 % electricity
40 – 50 % Heat
Motor Generator
BTPS
Gas engine
100 % Biogas
20 – 35 % electricity
45 – 55 % Heat
Motor Generator
BTPS
Technical Systems: Biogas Treatment and Utilization
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Technical Systems: Process Overview
Feedstocks
Crushing
Screening
Hygienization
Pre-treatment
Biogas treatment and utilization
Anaerobic digestion
Advanced treatment
Feeding into gas distribution systemUse as fuel
Desulfurization
Dewatering
Heat and power generation
Feeding into grid
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Technical Systems: Biogas Treatment and Utilization
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Technical Systems: Process Overview
Feedstocks
Crushing
Screening
Hygienization
Pre-treatment
Biogas treatment and utilization
Anaerobic digestion
Digestate storage
Land spreading
Advanced treatment
Feeding into gas distribution systemUse as fuel
Desulfurization
Dewatering
Heat and power generation
Feeding into grid
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Land spreading
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Farm Biogas-Reactor Chain
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Comunal Biogas-Reactor Chain
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• Economic Feasibility
• Legal Feasibility
Peculiarities of Framework
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ANALYSIS OF COSTS:•PROJECT DEVELOPMENT
•SALES OF ENERGY
•DISPLACEMENT OF FERTILIZER COSTS
•SALES OF CO2 EQUIVALENTS
•RUNNING COSTS
•TECHNICAL EQUIPMENT
⇒ FIXED COMPENSATION
ANALYSIS OF INCOME:
Framework: Economic Feasibility
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• WASTE AND DIGESTED MANAGEMENT
• ELECTRICITY INJECTION
• PREVENTION OF EMISSION
• RULES OF PLANNING AND CONSTRUCTION SAFETY
Framework: Legal Feasibility
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Degression 2%Laufzeit 15 Jahre
Degression 1%Laufzeit 20 Jahre
Degression 1,5%Laufzeit 20 Jahre
0
5
10
15
20
25
1996 1998 2000 2002 2004 2006 2008
Stromeinspeise-Gesetz (StrEG)
Erneuerbare Ener-gien-Gesetz (EEG)
Erneuerbare Energien-Gesetz (EEG) Novelle (150 kW;o.KWK;o. Tec)
ct/kWh
Novelle des EEGNovelle des EEGct/kWh NaWaRo KWK Tec
bis 150 kW 11,5 + 6,0 + 2,0 + 2,0bis 500 kW 9,9 + 6,0 + 2,0 + 2,0bis 5 MW 8,9 + 4,0 + 2,0 + 2,0über 5 MW 8,9 - + 2,0 -
Development of Biogas Utilisation in Germany
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0
500
1000
1500
2000
2500
3000
3500
4000
4500
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 20050
100
200
300
400
500
600
700
800
900
1000inst. MW el.Number of biogas plants Installed electrical pow
er [MW
]
Development of Biogas Utilisation in Germany
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decentralised energy supply4 livestock units powering1 household
diversification ofagricultural income
reduction ofodour
emission
CO2 – neutral energy supply1 kW el inst. = avoidance of 7,000 kg CO2/year
security of energy supply
reduction of CH4-discharge corresponding to1,500 kg CO2 perlivestock unit and year
strengthening ofrural infrastructure
saving of mineralfertilizers
up to 20 kg N perlivestock unit and year
Environmental Effects of Utilizing Biogas Technology in Agriculture
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Summary and Conclusions
• Technology of agricultural biogas plants significantly improved last two decades.
• Nevertheless, still considerable potential for optimization and development in the fields of:– Agitation– Biogas treatment– Biogas utilization– Plant dimensioning
• Profitability of biogas production and utilization strongly depends on legal framework and business environment.
• Keeping investment costs low and improving the efficiency of energy recovery are important factors to improve profitability of biogas plants.
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Thank you for your attentionThank you for your attention!!
MScMSc. Felipe Kaiser. Felipe Kaiser
Bavarian Research Center of AgricultureBavarian Research Center of AgricultureInstitute of Agricultural Engineering, Farm Buildings and Institute of Agricultural Engineering, Farm Buildings and
Environmental TechnologyEnvironmental Technology
Contact:Contact: [email protected]@LfL.bayern.dePhone:Phone: + 49 + 49 –– 8161 8161 –– 713792713792Address: Address: Am Am Staudengarten Staudengarten 3, 85354 3, 85354 FreisingFreising, Germany, Germany