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Jörg Bohlmann
Fichtner GmbH & Co. KG
Technical and commercial Aspects for the Development of Biomass and Biogas
Projects
5848A06/FICHT-7252383-v1
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Content of the presentation
Pathways for biomass utilizationBiogas
Biogas fundamentalsBiogas production technologiesPotential feedstockSpecial case: Landfill gas
Thermal processesCombustionGasificationPotential feedstock
Requirements and constraints for project development
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Basic conversion options for Biomass
Source: EIA, Potential Contribution of Bioenergy to the Worlds Future Energy Demand
Usual pathways for biomass utilization
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Waste and byproducts, no lignocellulosic
Energy crops (silage)
Energy crops(wood)
Sludge and manure
Waste and byproducts,
lignocellulosic
Organically polluted waste water
Waste on landfill
Combustion
Gasification
Anaerobic digestion
Anaerobic decay in landfill
Steam
Syngas(CO+H2)
Biogas (Methane)
Water steam cycle
Process steam
Internal combustion engine (CHP)
Heating
Grid injection
Thermo-Oil ORC-Modul
FEEDSTOCK PROCESS ENERGY CARRIER USAGE
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Part 1: Biogas
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Biogas Fundamentals (1): Basic components
Source: NNFCC UK
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Biogas Fundamentals (2): Process distinctions
Temperature
• Psychrophilic • < 20°C• No technical
application• Mesophilic
• 20°-40° (opt. 35°)
• High stability• Long retention
time• Thermophilic
• 50°-60°• Sensitive
process• Smaller
reactor• Disinfection
Water content
• No clear treshhold
• Dry >20 % DS• Wet < 15% DS• Wet process with
more experience
Operating regime
• Batch: No technical application
• Fed-batch• Continous
Stages
• One Stage• Hydrolysis and
methane formation in one reactor
• Two stages• Hydrolysis and
methane formationin two reactors
• Better adjustment of reaction conditions
• More equipment
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Polymeric substratesProteins Carbohydrates Fats
Organic acidsAlcohols
Amino acidsSugar
Fatty acids
HydrogenCO2
Acetic acid
Methane, CO2
Fermentativebacteria
Fermentativebacteria
Acetogenicbacteria
Methanogenicbacteria
Hydrolysis
Acid formation
Acetic acid formation
Methane formation
The Two-Stage Anaerobic Process relating to The Four Stages of Fermentation
Firstprocessstage =Hydrolysisstage
Secondprocessstage =Methanestage
Biogas Fundamentals (3): Stages of Fermentation
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Substrate
Biological degradability
Organic content
(COD, VS)
Nutrients composition
Water content
Hydraulic retension
time
Loading rates
Degradation rates
Fermentervolume
Biogasproduction
(quality and quantity)
Input parameter Energy yieldDimensioning
Biogas Fundamentals (4): Process parameters
Biogas: Potential Feedstock (1)
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Energy Crops
Low specific price Indepent from market
development Environmental friendly disposal If waste water: Climate
protection, Kyoto-Protocoll Fertilizer properties of residue
better than of manure Often continuous arising
Often low energy yield
Waste / byproducts
FeedstockSupply
Energy crops to the extend
required
High specifiy biogas yield Technical optimization of
fermentation Additional income from fallow
fields
Controversial ethical discussion (“burning bread”)
High price If not from own production:
Dependency from market fluctuations
Seasonal arising
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Potential Feedstock (2)
Data to be defined for process design
Amount of feedstock: Total amount, continuous supply
Quality Water content: Dimension of storage, fermentation
technology and reactor volume Organic content (e.g. COD, BOD): Decisive for
biogas yield.Concentration: Yield per VolumeTotal amount: Total yield
Constancy of feedstock properties: Technology to be designed to handle the maximum input.
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Potential Feedstock (3)
Co-fermentation of several feedstock types results in broader range of bacteria and a more stable process.
If waste is fermented, there might be legal requirements for sanitation and disinfection of the material (e.g. by high temperature)
Special case: Mono-fermentation of chicken manure critical due to high ammonia content.
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Lower capital costUse of standard-enginesHigher efficiency for small scale
plants.
Advantage Gas Otto Engine
Lower emissionsLower maintenance requirementsLarge units available (> 1MW)Higher lifetime (65,000 h vs 35,000 h)No additional fuel required
Biogas: Engines / CHP Units
Quelle: …..
Advantage Gas Diesel with pilot injection
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Biogas: Capital Cost CHP Units
Source: FNR Handreichung Biogas
Pilot injection
Gas Otto Engine
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Biogas: Cost of equipment
Specific capital costs for energy crop fermentation (Germany 2004)
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Biogas: Statistical data from Germany and conclusions (1)
Share of manure [%]
Source of diagrams: FNR
Most of the plants use Co-fermentation
There are about 15 % plants based on energy crops only
Installed el. Power [kW]
Typical plant size in Germany 250-500 kW
In Ukraine typical size may be higher because of larger farms
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Biogas: Statistical data from Germany and conclusions (2)
Operation hours [1000 h/yr]
Full load hours [1000 h/yr]Source of diagrams: FNR
66% of the plants achieve more than 8000 hours of operation per year
This is not necessarily full load operation!
More than 8000 full load hours can be achieved, however…..
About 50% fail to achieve 7500 full load hours
Careful assumptions regarding availability in business plan!
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Biogas: Statistical data from Germany and conclusions (3)
Full load hours [1000 h/yr]Source of diagrams: FNR
In most cases the simple internal biological fermentation is sufficient
Desulphurization
none intern externbiological
Precipi-tation
Adsorption
Typical reactor volume load 2-4 kg/m³.d
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Biogas: Grid Injection (1)
Definition of processes:
There are two main options to produce Methane from biological sources
Gasification and synthesis only in large centralized facilities.
Solid biomass
Thermo-chemical
gasificationBio-SNG
Methane syntesis
Manure / silage
Biogas production Biogas
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Biogas feedstock and production does not differ from biogas production for use in CHP units
Biogas must be treated according to grid specification Main parameters:
TracesHydrogen
-up to 4000 ppmH2S
-
1%25 – 40%Carbon Dioxide
93 – 98%50 – 70%Methane
Natural gasBiogas
Biogas: Grid Injection (2)
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Overview on most usual treatment technologies
Biogas: Grid Injection (3)
Pressure swing adsorption
• 97% CO2
• Many references• High electrical
demand, no heat demand
• Prior drying and desulphurization
• No chemicals• High methane slip
Amin scrubbing
• 99% CO2
• Some references• High heat demand• Chemicals• Very low methane
slip
Pressurized water scrubbing
• 98% CO2
• Many references• High electrical
demand• No chemicals• High methane slip
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Special case: Landfill gas (1)
Municipal solid waste contains significant amount of organic waste which, in the absence of air, starts a fermentation process producing methane.
The gas should be collected and burned because of the high greenhouse activity of methane
The landfill is a biogas reactor, but The feedstock is not defined the content is not mixed or stirred the reaction conditions are not defined air access can not be excluded no new feedstock is supplied
Projects have to deal with high uncertainties in landfill gas production rate and properties.
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Special case: Landfill gas (2)
Principle of landfill gas utilization
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Special case: Landfill gas (3)
Source: Bogon, H.: Deponiegasprognose, worauf kommt es an?www.oekobauconsult.de/Deponiegasprognose_Vortrag.pdf
Methan production rate calculated [m3/h]
Me
tha
n p
rod
uc
tio
n r
ate
me
as
ure
d [
m3
/h]
Uncertainties of methane prognosis
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Landfill gas production: Typical Curve
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
0.0
200.0
400.0
600.0
800.0
1000.0
1200.0
spez. Gasmenge (in m3/h)Gasmenge (in m3/h) bei 50 % / 40 % und 30 % Erfassung
Gas
men
ge
in m
³/h
Source: Rettenberger: www.ruk-online.de
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Special case: Landfill gas (4)
Aspects to be considered There must be a legal basis for gas utilization, e.g.
concession. Dimensioning of equipment must be done carefully:
Start small and extend after gas supply is PROVEN. Gas production decreases after closing of landfill:
Dimensioning not for peak production. Landfill gas is from WASTE and may contain many
impurities: Only engines from experienced suppliers should be used.
As a rule there will be no heat offtake at the landfill: Feed-In tariff decisive for economic viability
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Part 2: Thermal Processes
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Distinction thermal processes
•Air ratio >1
•Hot flue gas
Combustion•Air
ratio < 1
•Syngas (H2
, CO, (N2
)
Gasification
•Air ratio = 0
•Hydrocarbons (gas, oil)
Pyrolysis
•Biological process
•Methane
Anaerobic digestion
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Distinction thermal processes
•Air ratio >1
•Hot flue gas
Combustion
•Air ratio < 1
•Syngas (H2, CO, (N2)
Gasification
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Biomassekraftwerk Mannheim der MVV (20 MWel)
Bildnachweis: MVV-Pressebild, http://www.mvv-energie-ag.de
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Bildnachweis: Fortum Service Deutschland GmbH
Biomasse-HKW Herbrechtingen (15 MWel)
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Scheme of a conventional Biomass Powerplant
Bildnachweis: Babcock & Wilcox Volund, http://www.volund.dk
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Scheme of a Fluidized Bed Boiler for Biomass
Bildnachweis: Austrian Energy & Environment, http://www.aee.co.at
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Scheme of water cooled combustion grate
Bildnachweis: Babcock & Wilcox Volund, http://www.volund.dk
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Typical key design data for biomass fired plants
1.300 m² 5 m high 38.500 t/a
5 MW el
6000 to 8000 h/a Steam 420 °C, 60 bar
36.000 m3/h 80 kg/h
10 MWth, 3,6 MWel
2.500 m² 5 m high 73.500 t/a
10 MW el
69.000 m3/h 155 kg/h
20 MWth, 7,2 MWel
4.500 m² 5 m high 130.500 t/a
20 MW el
120.000 m3/h 280 kg/h
20 MWth, 16,5 MWel
Text
10 days storage
Boiler / furnace
Flue gas flow Cleaning residues
CHP-mode
5,5 t/h 10,5 t/h 18,6 t/h
10 - 15 15 - 20 20 - 22 Personnel
3000 – 3500 €/kW 2500 – 3000 €/kW 0 2000 – 2500 €/kW CAPEX
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Specific CAPEX for biomass fired powerplants
0
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
9.000
10.000
0 2 4 6 8 10 12 14 16 18 20
Elektrische Leistung in MW
Sp
ez.
Inv
es
titi
on
sk
os
ten
in T
€/M
We
l
KW od. HKW mit Enth.-Kond.betrieb
HKW mit Gegendruckbetrieb
Potentiell (HKW mit Gegendruckbetrieb)
Potentiell (KW od. HKW mit Enth.-Kond.betrieb)
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Biomass Combustion: ORC Process
The ORC (Organic Rankine Cycle) works like a conventional water/steam cycle, but applies organic liquids instead of water.
ORC-Process has been developed to utilize low-temperature heat (e.g. geothermal power).
Meanwhile there are solutions also for use in biomass plants Disadvantage:
Low electrical efficiency Heat sink required
Advantage: Predesigned packages Easy operation No Condenser needed
Typical application: Pellet factories with constant heat demand
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Bildnachweis: Kohlbach Holding GmbH, http://www.kohlbach.at
ORC-Holzheizkraftwerk Sauerlach (0,5 MWel)
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Biomass Combustion: Scheme of ORC-Process
ORGANIC FLUID
THERMAL OIL
BOILER
BIOMASS
EVAPORATOR
PREHEATER
G
TURBINE
REGENERATOR
DRYING
CONDENSOR
POWER PLANT FACILITY
COOLING WATER
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Biomass Combustion: Thermo-Oil Boiler for ORC
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Biomass Combustion: ORC – ModuleExample: Turboden
Source: Turboden
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Biomass Combustion: Design Data ORC-PackagesExample: turboden
Source: Turboden
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Distinction thermal processes
•Air ratio >1
•Hot flue gas
Combustion
•Air ratio < 1
•Syngas (H2, CO, (N2))
Gasification
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Gasification: Distinctive design features (1)
Gasification
Fluidized Bed
Combinations / others
Entrained Flow Gasification
Fixed bed gasifier
Gasification medium steam
Allothermal
Autothermal
Gasification medium oxygen
Gasification medium air
Gasification means combustion under starved air conditions: Hydrocarbons + Oxygen CarbonMonoxide plus Hydrogen
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Gasification: Design features
Fluidized bed Lower tar content Only for larger plant sizes (> 2 – 5 MW fuel heat)
Fixed bed For smaller unit sizes (up to 1 MWth)
Numerous projects failed due to problems with availability and gas quality.
Gasification with oxygen: Only for large plants. Entrained flow gasifier: Pretreatment required, only large plants.
Gasification: Distinctive design features (2)
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Schemes of basic types of gasifiers
Counter-current fixed bed Co-current fixed bed
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Schemes of basic types of gasifiers
Biomasse
Synthesegas Verbrennungs-Abgas
VerbrennungsluftDampf
Fluidized bed („Güssing-Type“) Entrained flow
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Gasification: Typical process configuration
G
90 °C
70 °C
120 °C
Gas cleaning
470 °C -580 °C
20 °C
Gasifier
CHP - Engine
Heat Exchanger
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Gasification: Technical problems:
Especially in fixed bed gasifier it is difficult to maintain constant reaction condition in the whole reactor.
As a consequence, there are zones where only pyrolysis takes place and tar is created.
Gas scrubbing is possible, but will create a waste water problem. Gas scrubbing with POME (Biodiesel) is possible.
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Bildnachweis: RENET Austria, http://www.renet.at
Holzvergasungs-Kraftwerk Güssing (2 MWel)
Succesfull operation with Jenbacher gas engine
Comparatively large plant Special design two-stage
gasification
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Gasification: The Tar Issue
Photos taken recently at a fixed bed gasifier in Germany
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Gasification: Future options:
Biomass gasification as source for synthesis gas provides interesting perspectives for the future: Production of synthetic biofuel (BtL, biomass to liquid) Production of SNG (Synthetic natural gas) Production of Methanol / Ethanol / DME
All these processes will require large entrained flow gasifiers
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Project Development: Requirements and Constraints (1)
BiomassProject
Feedstock supply• Security of supply / Own sources• Seasonal arising / storage needs• Specification: Interface to technology• Cost of feedstock
TextEnergy offtake• Green Tariff? Long term security?• Responsibility for grid tie in• Heat offtake: Long term security, seasonal fluctuations / load curve
Project preparation• Thorough planning & design• Proposals for main equipment• Site / feedstock specific approach
Risk assessment• Project risks clearly identified• Countermeasures• Contingencies
Thank you for your attention
FICHTNER GmbH & Co. KGSarweystraße 370191 Stuttgartwww.fichtner.de
Joerg Bohlmann
Telefon +49 (0)711 8995-284Telefax +49 (0)711 8995-495E-Mail [email protected]
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Project Development: Requirements and Constraints (1)
Fermentation technology
Suitability for feedstock Adjustment of fermentation technology to the feedstock: Has the
feedstock been investigated in detail? Has the gas prognosis been adjusted to the mix? Reference situation of envisaged supplier
Type of feedstock Project region
Complexity Adjustment regarding environment Requirements regarding skilled operation personnel
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Project Development: Requirements and Constraints (2)
Feedstock supply
Long term security of supply: Own sources? Waste and byproducts? Market situation?
Constancy of supply: Seasonal arising? Storage required (Conservation)
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Project Development: Requirements and Constraints (3)
Energy offtake
Electricity: Grid tie-in secured? Responsibility? Green tariff? Long term security?
Heat offtake: Heat offtake secured? Load curve / seasonal demand? Long term security of offtake (Market for offtaker?)
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Source : FNR
60Source : FNR
61Source : FNR
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