Technische Universität München
The Role of Solid Fuel Conversion in Future
Power Generation
Hartmut Spliethoff
FINNISH-SWEDISH FLAME DAYS 2013
“Focus on Combustion and Gasification Research”
Jyväskylä, April, 17th and 18th 2013
Technische Universität München
Content
1. Future Developments
1. Worldwide
2. Germany
2. Power Station Requirements
3. Technologies - What Power Plants are required?
4. Research Demand for Solid Fuels
5. IFRF Research
6. EF Gasification Research at TUM
Technische Universität München
1. Future
Primary Energy – World, New Policies Scenario
IEA, WEO 2011
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2. Requirements
Power requirements – Situation Germany 2010
Source: Spliethoff: et. al, CIT 2011
Today (2010): Share of renewables 16 %, Wind 26 GW, PV 17 GW
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2. Requirements
Power Requirements – Germany 2020
Source: Spliethoff: et. al, CIT 2011
Requirement for low minimum load
2020: Wind 46 GW, PV 50 GW, Constant consumption
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2. Requirements
Power Station Requirements
Efficiency
Investment costs
Flexibility
• Future:
• Operational hours ↓ Investment costs ↓
• Flexibility:
• Start-up time ↓ , minimal load ↓
• Load change capability ↑
• Efficiency ??
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3. Technologies
Technologies for the future
Source: Spliethoff: et. al, CIT 2011
- Storage technologies:
- Long term: chemical storage
- Power to heat
- Flexible conventional power generation for balancing
- Combined Cycle the preferred technologies
- Pulverized Coal Power Station with low investment costs
- Integration of storage technologies
- Renewables:
- Biomass
- Waste
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3. Technologies
Comparison Flexibility: CC versus PC
Source: Spliethoff: et. al, CIT 2011
Combined
Cycle (new)
Pulverized Coal
Power Station
new old
Load Change 3-6 % / min 3-6 % / min
2-4 % / min
Minimum
load 25 % (2 GT) 20 % 40 %
Start-up
hot (8h)
warm (48 h)
0,5 – 1 h
1- 1.5 h
1-2 h
3 h
2 h
4-5 h
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3. Technologies
Ongoing developments - PC
Source: Spliethoff: et. al, CIT 2011
• Reduction minimum load
– Firing stability determines
minimum load:
– Requirement: safe operation in
case of a mill failure
– Bituminous coal: Reduction for
pure coal firing: 35-40 % 20
%
– Brown coal: Reduction from
appr. 50 % to 20 % by predrying
• Operation without power production
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3. Technologies
Gasification - challenges and opportunities
Gasification
Efficient CO2-
separation
Chemicals and energy
carriers/ polygeneration
Power Production
(IGCC)
Flexibility in the
context of increasing
renewables
+ High efficiency
- Costly
- Low availability
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3. Technologies
Gasification - challenges and opportunities
Chemical
Synthesis • Methanol
• SNG
• FT liquids
Gasifier
Storage
for SNG and FT
fuels
infrastructures
are already
present
Electrolysis
19
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3. Technologies
IGCC-EPI: Excess Power Integration
Entrained flow
gasifier
Quench/
HRSG
Synthesis
Gas-
turbine
Electrolysis Gas grid O2-storage ASU H2-storage
HRSG Coal
H2S Exhaust gas
SNG O2 H2
O2
H2
0-100%
0-100% 0-100%
0-100%
50-100%
100%
El.
Energy
El. Energy El. Energy
Steam
turbine cycle Rectisol
Excess power
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3. Technologies
Waste
Electrical Efficiency
- Europe, average: 13 %
- new conventional plants: 18 %
Zella Mehlis, Germany
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3. Technologies
Biomass
Source: hs energieanlagen gmbh
Biomass CxHyOz
Fluidized bed
gasification
Methanation
SNG
Source: www.skymeshgroup.com
Gas cleaning,
tar, sulphur,…
23
Entrained
Flow
gasification
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4. Research Demand
Conversion
Raw coal
H2O Volatiles
Heating/ drying Pyrolysis Char combustion Ash
CO2, H2O Volatiles
combustion
Step De-
mand
Examples
Pyrolysis 2 Kinetics, composition, impact on char structure
Volatile comb. 3 Gas phase combustion
Char
combustion
1 Kinetics for O2, CO2, H2O, char structure and reactivity
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4. Research Demand
Emission – Example NOx emission
- Demand: extensive research in the past and secondary measures lower
research demand
- Key: Distribution volatile N and char-N
raw coal
Fuelnitrogen coal char
char
N2
N2
NO
N
Volatiles
Volatil
N
fixedN
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4. Research Demand
Ash related issues
- Ash makes the difference to gas
combustion
- Operational problems such as
slagging, fouling and corrosion are
domnination design and operation
- Research demand:
- Ash formation
- Ash chemistry
- ……..
charcombustion
Evaporation
anorganicvapours
NucleationCoagulation
heterogeneouscondensation
fragmentation
Tail cokeparticle
coalparticle
Mineral inclusions
ashparticle
I
superfineparticle(0,1 µm)
II
agglomeratedash particle(0,1 - 10 µm)
III
flyash(1 - 20 µm)
Technische Universität München
4. Research Demand
Gasification
• Gasification offers a high potential (integration, membranes)
- with CCS η < 40 %
- without CCS η ≤ 50%
• CCS power plant today is based on available technologies
Gasifier Gas
cleaning
High T
shiftLow T
shift
CO2
separation
Coal H2
CO2
Conve
ntio
nal Gasifier Gas
cleaning
High T
shiftLow T
shift
CO2
separation
Coal H2
CO2
Gasifier Gas
cleaning
High T
shiftLow T
shift
CO2
separation
Coal H2
CO2
Conve
ntio
nal
Gasifier Gas
cleaning
Membrane
shift
Coal H2
CO2
Me
mbra
ne r
ea
ctor
Gasifier Gas
cleaning
Membrane
shift
Coal H2
CO2
Me
mbra
ne r
ea
ctor
KEY for future development: Knowledge of coal behaviour including mineral
matter/ trace components at highest temp./ pressures and reducing conditions
• Gasification is an old technology ↔ knowledge base is low
Technische Universität München
4. Research Demand
Fuel characterization and CFD-modelling
Requirement for design and operation: to know the impact of
- fuel quality and
- combustion conditions
Approach:
• Fuel Characterization: Advanced FC, which consider large scale
combustion conditions
• CFD modelling: data of fuels and ashes required
on
- Combustion behaviour,
- Emissions
- Slagging, fouling and corrosion
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• Characterise solid fuels
– to fill data gaps for numerical model validation
& application
– includes fuels that are environmentally and
economically significant
• Biomass, Wastes, Blends with coals
• In atmospheres that reflect O2/RFG
approach, temperatures and pressures of
current interest to members and other
sponsors (steam, CO2)
• Establish protocols for solid fuels
combustion/gasification characterisation
• Produce and maintain DATABASES (IFRF Solid
Fuel Database- http://sfdb.ifrf.net
5. IFRF Research
IFRF - Fuel characterization
Technische Universität München
• Length 4 m, ID 0.15 m
• 8 modules, 19 feed ports
• quenched collector probe
• 60 kW burner, 54 kW
resistances
• 700-1400°C
• 5-1500 ms residence time
• carrier gas (O2, N2, CO2 mix)
conditions similar to those of
full scale plants
5. IFRF Research
The IFRF Isothermal Plug Flow Reactor (Livorno – Italy)
Technische Universität München
Issues:
• Temperature is really isothermal?
• Particles residence time
distribution – trajectories
• Partciles actual T vs time history
CFD modeling can help to correctly
analyze and interpretate the raw
data produced by IPFR.
5. IFRF Research
IPFR Qualification:
CFD modeling
Technische Universität München
• Straw pellets (Denmark)
• Torrefied Spruce (BE 2020)
• Sofwood pellets (BE 2020)
• DDGS (TUD)
• Palm Kernel Shell (+ torrified) (KTH & Poland)
• Lignine (Italy)
• Sunflower seeds (Italy)
5. IFRF Research
Materials
Technische Universität München
experimental data with error bars and sub-model fitting
5. IFRF Research
IPFR - Conversion versus time/ T, gas composition
Technische Universität München
6. Gasification Research at TUM
Research Project -
Industry Partner: Siemens, Air Liquide, RWE, EnBW, Vattenfall
Research Partner: TUM, TUB Freiberg, FZ Jülich, GTT
CFD
Simulations
IGCC
Concepts Trace Species
Condensation
Gasification
Kinetics
In-situ
Monitoring
Technische Universität München
6. Gasification Research at TUM
Pressurized High Temperature EF Reactor (PiTER)
Technical Data
Temperature: up to 1800°C
Pressure: up to 5.0 MPa
Residence time: 0.5 – 5 s
Feed: pulverized coal
Fuel mass flow: up to 5 kg/h
Gas vol. flow: max. 100 mN³/h
Gas composition: N2,H2O,CO2,H2,
O2,CO
Reactor height: 7000 mm
Reaction tube
length: 2200 mm
inner diameter: 70 mm
• Experiments at pressure
• Gasification in CO2/H2O/O2
• Pyrolysis in inert atmospheres
• Char and gas analysis 7 m
1 m
Technische Universität München
6. Gasification Research at TUM
Experimental facilities – Babiter, WMR and PTGA
Optical
ports
Pressurized
heating system
Balance system
PWMR1100°C, 5.0 MPa
Sample
Coal
feederGas
preheater
Heating
zones
Water
quench
Sampling
probeChar
filter
Gas
analysis
PTGA1600°C, 5.0 MPa
BabiTER1600°C, atmospheric
(a) (b) (c)
0
200
400
600
800
1000
1200
0 1 2 3 4 5 6
Tem
pera
ture [
°C]
Time [s]
0.1 MPa
1.0 MPa
2.5 MPa
5.0 MPa
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6. Gasification Research at TUM
Reaction kinetics in a technical EF Gasifier
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Conclusions
• Relative decrease of coal utilization in the medium
and long-term, but absolute increase in the short
and medium term
• Importance of biomass and waste fuels
• Increase of fluctuating renewables requires flexible
power plants
• Research in solid fuels is still required