Biofuels - Åbo Akademiweb.abo.fi/instut/biofuelsGS-2/kursen/Norge/Part 2.pdf · • Biofuels can...
Transcript of Biofuels - Åbo Akademiweb.abo.fi/instut/biofuelsGS-2/kursen/Norge/Part 2.pdf · • Biofuels can...
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Biofuels
Prof. Johan E. Hustad
Department of Energy and Process EngineeringNTNU
Norway
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Biofuels are hot again - this time it’s the global warming
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Introduction Characterisation, resources Fuel prices, trade, politics
Process routes and options
Technologies and cycles Combustion/Co-combustion Gasification/gasification-combustion
Producer gas impurities and gas/particle cleaning
Examples of projects at NTNU/Sintef
Biofuels for transport
Poly/tri-generation biomass systems
Conclusions
Outline
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Biofuels – some examples
Wood
Chips
Pellets
Charcoal
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Brenselanalyser
Direkte Analyse (Proximate Anlysis)- Fuktighet (moisture content) [vekt%]- Flyktige Bestanddeler (volatile matter) [vekt%]- Fast Karbon (fix-C) [vekt%]- Aske (ash) [vekt%]
Analysen gjøres på rått brensel
Elementanalyse (Ultimate Analysis)- Karbon C [vekt%]- Hydrogen H [vekt%]- Oksygen O [vekt%]- Nitrogen N [vekt%]- Svovel S [vekt%]
Analysen gjøres på tørr og askefri basis (DAF)
Brennverdi (Heating Value) [MJ/kg]
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Motivation
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33 TWh
20 TWh
Forest Biofuels in Norway
Kilde: SSB, NIJOS, Petter Heyerdahl (UMB)
FUEL MARKET POTENTIAL
WOOD FUEL PRICES (Euro/MWh)
EU-Politics, regulations
•RES increase from 6% (1997) to 12% (2010)
RES-E incr. from 14% (1997) to 22% (2010)
Energy Performance Certificate in Buildings (Savings, Space Heat., DH, reduce FF)
Solid Biofuel Standardisation – CEN TC-335
Biofuels Directive to replace gasoline and diesel by 2% in 2005, 5.75% in 2010 and 20% in 2020
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Energy from biomass. Routes and options
bio-diesel
methanol
FT-liquids
substitute natural gas
ethanol
oil
biomass
& biomass waste
& energy crops
electricity
work
&
movement
Hydrogen (H2)
FUELS INTERMEDIATE PRODUCTS / SECONDARY ENERGY CARRIERS
FINAL PRODUCTS
engine
engine
engine
engine
engine
eng/turbine
Combustion + steam cycle or Stirling
extraction
fermentation
pyrolysis
hydrogasif. or digestion
gasification
biological processes
synthesis
Synthesis gas (CO + H2)
reforming
eng/turbine
fuel cell
generator/engine
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Small scale combustion
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Medium/Large scale combustion
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5 – 100 MW
Fluidized bed
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Waste combustion
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Co-combustion – Pulverized fuel
Gasification
GAS CLEANINGUPGRADING
FEEDSTOCKSYN-GAS
FEEDSTOCK
AIR (STEAM)
ASH LCV: 4-6 MJ/Nm3 (air)MCV: 10-15 MJ/Nm3 (steam)Naturgass: 40 MJ/Nm3
SOFCFUEL CELL
GASENGINE
GASTURBINE
COMBUSTION
HOMOGENEOUS REACTIONS
CO2, H2O,,,NOx
CO, CO2, H2, H2O,,,NOx
HETEROGENEOUSREACTIONS
PYROLYSIS
Char, Tar, CO, CO2, H2, H2O, CxHy,NOx
H2O
DRYING
FEEDSTOCK
FEEDSTOCKOXIDIZER
FEEDSTOCKLCV-GAS FEEDSTOCKEMISSIONS
FEEDSTOCKASH
FEEDSTOCKOXIDIZER
SNTEF project - CFD-modeling of gasification/combustion
[energy from biomass]
RENEWABLE ENERGY NETWORK AUSTRIA
CHP- Plant Güssingelectricity
heat
To Synthesis Plants
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Gasification – co-combustion natural gas
Steam turbine
BoilerBurner
Combustionchamber
Air
Compressor
Natural gas
Gas turbine
Gasifier
Biomass
Flue gas
Natural gas
Supplemental firing
Biomass gasProcess steam
SINTEF project - Duct burner: Co-fire of natural gas and syngas
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Gasification –co-combustion coal
Air inlet
Biomass feeding
Gas analysis
Filter
Flare Motor
Generator
Product gas (H2+ CO)
Gasification reactions
C(s) + H2O + heat CO + H2
C(s) + CO2 + heat 2CO
Biomass gasification for heat and power production
Stratified downdraft gasifier
Reactor dimensions
Diameter: 100 mm
Height: 500 mm
Feeding rate
4-6 kg/h wood pellets
Air supply
6-8 Nm3/h (8-10 kg/h)
• Controlled and stable operation.
• Air excess ratio: 0.25-0.30
• 23-26% CO, 14-16% H2, 1.5%CH4, 46-49%N2, 8-11%CO2
• 10 -14 Nm3/h of product gas.
• Energy output: ~18 kWth
•Low heating value: 5.3 - 5.7 MJ/Nm3
• Cold gas efficiency: 52-64 %
• Tar content: 3 g/Nm3
( )nCOc pkr 2=
COb
COf
COfc
pkkp
kk
pkr
3
12
3
1
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1 ++=
nth order Langmuir-Hinshelwood
fk CCOOC +→ 3)(
)(2 1
12 OC
k
kCOC
b
ff +
fk CCOOC +→ 3)(
)(2 1
12 OC
k
kCOC
b
ff +
Reaction kinetics and models
COMBINED HEAT & POWER
Stirling engine
Micro turbines
Organic Rankine cycle
Unsuitable for
biomass
Suitable for
biomassFuel cells
Nordic Seminar- Thermochemical Conversion of Biofuels, Trondheim 21 Nov. 2000, Norway
IntroductionBioSOFC – Project contents and goal
Goal: Technology development for integrated SOFC, biomass gasification and high temperature gas cleaning
Normal operation
Cleaned gas
Coarse sandFine sand
Dust cake
Uncleanedgas
Particulate gas cleaning in combustion and gasification processes
- The Panel Bed Filter, working principle -
Regeneration
Cleaning pulse
Dust cake
Nordic Seminar- Thermochemical Conversion of Biofuels, Trondheim 21 Nov. 2000, Norway
Panel Bed Filter
• Glass cover for the thermocouple
• Glass disc to avoids flow towards top/gasket
H2S removal reactor
Sorbent screening:– Temperture curves, flow rates, fuel gas
concentrations, influence of water
SOFC unit
Cooling cup
SOFC
Detail of the upper part
Single cell test I - Setup
OCV @ different feed composition1000C
0.7620.7640.7660.768
0.770.7720.7740.776
50 75 75 0 20050 50 75 25 20050 25 75 50 20050 0 75 75 200
N2+H2+CO2+CO+Air[ml/min]
Single cell test I - Results
50+0+75+75+200 [ml/min] N2+H2+CO2+CO+AIR 1000C
0.68
0.7
0.72
0.74
0.76
0.78
0 0.5 1 1.5Current [A]
Cel
lVo
ltag
e [V
]
Voltage drop:
0.089V per 1A
Power:
0.69W @ 1A
Single cell test I - Results
50+75+75+0+200 [ml/min]N2+H2+CO2+CO+AIR 1000C
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 0.5 1 1.5 2 2.5 3 3.5
Current [A]
CellV
olta
ge [V
]
Voltage drop:
0.054V pr 1A
Power:
0.72W @ 1A
Single cell test I - Results
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Three different technologies will coexists for production of biofuels
Hydrolysis Fermentation Distillationsett inn bilde
av hvete
Bioethanol
sett inn bilde av rapsolje
Esterification Separation
Biodiesel
Gasification Catalysed synthesis Distillation
Biodiesel
Biodiesel
Bioethanol
Biomass to liquid (BTL)
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Both agricultural and wood based materials are involved in biofuels production
Biomass to liquids (Second generation)
Biodiesel
Rapeseed
Europe, Canada, China, Russia
Palm
Indonesia, Malaysia, Nigeria
Jatropha
Africa, South Eastern Asia, India
Switchgrass Miscanthus StrawBagasse
Bioethanol
Sugar cane
Brazil, India, China, Colombia
Corn
US, China
Sugar beet
Europe, China
Wheat Europe,
India, China, US
Wood
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Bioethanol and biodiesel have different properties
Bioethanol• CH3CH2OH• Can be blended with gasoline (up to ~10%) or used in special cars• Commercially available• Brazil is the largest consumer
Biodiesel• Depends on raw material, typically C10H22 to C15H32
• Can be used in today’s diesel cars• Commercially available from agricultural crops• Germany is the largest consumer
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World production of bioethanol eight times that of biodiesel
0
3
6
9
12
15
18
2001 2003 2005
Mtoe
0
3
6
9
12
15
18
2001 2003 2005
Mtoe
Production of bioethanol dominated by Brazil and US Production of biodiesel dominated by Europe
BrazilUnited StatesRest of the world
GermanyFranceRest of the world
Source: IEA World Energy Outlook 2006
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Gasification of biomass is flexible with respect to raw materials and end products
Gasification
Fischer-Tropschprocess Biodiesel
Methanol production
DME-production
Hydrogenproduction
Methanol
Dimethyleter
Hydrogen
Wood/Wood waste
Agricultural materials
Sewagesludge
Biogas
Organicwaste
Black liquor
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Syntetic fuels - Choren
[energy from biomass]
RENEWABLE ENERGY NETWORK AUSTRIA
0
1
2
3
4
5
6
7
8
9
5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41
Cn
Con
cent
ratio
n [M
ol %
]
FT-Diesel
FT-product in off gas (condensed)
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Wide range in LCA results (1)
63% GHG savings per v-km
16% GHG savings per v-km
Concawe, et al., 2004.
[energy from biomass]
RENEWABLE ENERGY NETWORK AUSTRIA
BiomassGasification
Producer Gas (gas engine, gas turbine,
fuel cell)
Synthetic NaturalGas (BioSNG)
FT-Fuels(BioFiT)
Methanol
Hydrogen
Others (e.g.DME)
Biomass
The basic concept –“Green Chemistry”
[energy from biomass]
RENEWABLE ENERGY NETWORK AUSTRIA
Efficiencies in Case of Polygeneration
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20
40
60
80
100
Gas engine BIGCC FT FT POLY BioSNG BioSNG POLY
Synfuel Electricity District heatCHP-plants Fischer-Tropsch Bio-SNG
Fuel orientation
Fuel orientation
%
[energy from biomass]
RENEWABLE ENERGY NETWORK AUSTRIA
BioSNG-production BioFiT– liquid fuel production
Biomass
Biomass gasification
Fischer-Tropsch BioFiTSlurry bed reactor Temperature 200-300°C Pressure 20-30 barCapacity ~ 10 Nm³/h Catalyst 2005: Iron
2006: Cobalt
nCO + 2nH2 = nCH2 + nH2O
Conclusions
• Biofuels can be utilised in a large range of processes and by the use of many different technologies at different scales.
• Biofuels will play an increased importance in the energy system in the future.
• Biofuels is the only renewable energy resource which can be used in both heat, electricity and transport applications.
• The most important processes will be combustion and gasification. • Combustion and co-combustion will be most important for heat,
power and CHP applications.– Particles, UHC, CO small plants– Fouling/slagging (Cl, K, S, Na) larger plants
• Gasification/combustion/co-gasification can be the source of both (heat), electricity and transport fuels including hydrogen– Gas cleaning like tars, H2S, particles, alkali metals and chlorine
compounds • Gasification also has the potential for advanced processes like
high temperature fuel cells.