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Coal gasification in low emissions power:
New tricks for an old dog!
Dr David Harris
Theme Leader – Advanced Coal Technologies
CSIRO Energy Technology
Engineers Australia – Sydney Division
Southern Highlands & Tablelands Regional Group
Mittagong, NSW
26 April 2007
Outline
Australian Coal and Power Industries
Export Coal Industry
Domestic Power Industry
Energy Policy in Australia
Coal in Sustainable Development
Australian Industry and Research Initiatives
Industry, Research & Government partnerships
Clean Coal Research and Technology Strategies
Coal‘s role in future energy demand
‗Clean Coal Technology‘ options and research needs
Coal gasification and related research
Future Directions
Research and Development
Demonstration and Implementation
Coal is important to Australia
Australia is the world‟s largest coal exporter & coal is
Australia‟s greatest export earner
$17B in 2004-05, $24.5B in 2005-06
Most of Australia‟s electricity is from pulverised coal fired
boilers
60% black coal, ~25% brown coal
Australia‟s coal related energy research has two main thrusts
Assessment of coals for export markets
current and new technologies – collaborative projects with coal users
Coal and technology issues for domestic power generation
Coal and technology - operation issues
Technology development needs – cost reduction, reliability
improvement
New technology pathways – familiarisation and risk assessment
Electricity Demand in Australia
Electricity demand expected to increase by >2%pa 2005-2020
50% increase in capacity needed
0
200
400
600
800
1000
12009
8-9
9
99
-00
02
-03
04
-05
07
-08
09
-10
12
-13
14
-15
17
-18
19
-20
Financial Year
Ele
ctr
icit
y G
en
era
tio
n (
PJ
)
Other
Biomass
Oil
Hydro
Gas
Brown Coal
Black Coal
Australia‘s Dilemma
Market deregulation
Breakup/privatisation of
power utilities
Cost competitive, coal
power generation
New renewables not cost
competitive
Close to World‟s lowest
power costs
Mandated renewables target
Efficiency standards for
power generation
Increased environmental
regulations
National and International
pressure for LET‟s
Emissions trading
Carbon taxes
Cost Competitive
Power
Lower GHG
emissions
Tension
Policy Drivers and Facilitation Initiatives
Industry/Government/Research partnerships
Developing policies to accelerate evaluation and deployment of advanced coal technologies in Australia
Facilitating improved coal use in new technologies & coal export markets
Several major research initiatives have been taken…
eg Cooperative Research Centres (CCSD), ACARP, COAL21, cLET, CISS, CSIRO Flagship program (‗Energy Transformed‘)
National & International collaborative initiatives to stimulate Demonstration and Implementation
Low Emission Technology Demonstration Fund – LETDF (2005-2010)
$500M – requires 1:2 co-investment with industry
Coal21 fund ($300M, 2006-2010)
US-Australia Climate Action Partnership (2002-)
Asia Pacific Partnership (AP6) (2005/06-)
Key R&D Partnerships – Clean Coal
Technologies
Cooperative Research Centres
CRC for Coal in Sustainable Development
CRC for Clean Power from Lignite (concluded 2006)
CO2CRC (CO2 capture and storage)
Centre for Low Emissions Technology (cLET)
Qld Govt, CSIRO joint venture – generators, ACARP, UQ partners
Enabling Technologies – gas cleaning, processing, separation
Australian Coal Association Research Program (ACARP)
COAL21 - Industry, Government, Research groups
Development of technology and policy action plan and roadmap
COAL21 Fund – support demonstration & implementation
CSIRO Energy Transformed Flagship
broad strategy – specific GHG targets
CSIRO Energy Technology‟s work is fully embedded in collaborative initiatives:
Clean Coal Research and
Technology Strategies
‗Clean Coal‘ Strategies
Improve efficiency of existing technology
> A$40 billion invested in PF power stations
Existing infrastructure has >30 years of operation life remaining
Desirable to retrofit improved technology add-ons
Address life-cycle emissions
Mining, preparation, utilisation
Fuel Switching
Fuel blends, coal preparation strategies
reduce greenhouse & particulate emissions
enable coal use in advanced systems (UCC etc)
Co-firing coal/biomass etc
Adoption of high efficiency technologies
Coal performance in advanced power technologies
Cost and reliability demonstrations required
Carbon sequestration
CO2 capture from existing and new technologies
„zero emissions‟ technology
Technology efficiency impact on CO2 emissions
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
30 40 50 60
Brown coal pulverised fuel
Thermal efficiency %
To
nn
es
CO
2p
er
MW
h (
Ele
ctr
ica
l)
Black coal pulverised fuel
Brown coal Integrated Drying
Gasification Combined Cycle
Super/ultra critical pulverised fuel
Black coal Integrated
Gasification Combined Cycle
Integrated gasification fuel cell
Open cycle gas turbine
Combined cycle gas turbine
In use
Future
Current Australian
technology
A Coal Roadmap
Technical Innovation
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
• Brown coal
drying
• Ultra Clean
Coal
• Improved coal
preparation
• Super & ultra
critical steam
cycles
• Oxy-firing
• Integrated (Drying)
Gasification
Combined CycleCoal upgrading
Improved pf
Flue gas
Advanced cycles
CO2 Stream
• Post combustion capture
• Pre-combustion capture
• CO2 sequestration
Near zero emissions
Efficiency
Potential
Sequestration
• Integrated
gasification fuel
cell
CO
2T
/MW
h
Incre
asin
g C
ost
Low Emissions Power Generation
Capture of
CO2
Coal
Energy
Conversion
Post-combustion capture
GasificationCO
Shift
Pre-combustion decarbonisation
Energy /
Power
or H2 / CO
Energy
Conversion
ASU Oxy-fuel combustion
Energy / Power
CO2/H2
separation
Storage/Use
of CO2
Capture of
CO2
Source: adapted from IEA Clean Coal Centre
Syngas
(CO+H2)
CO2 Sequestration
Source: CRC for Greenhouse Gas Technologies
Post-Combustion CO2
Capture (PCC)
Special Attributes of PCC
Only practical option for existing plants to substantially reduce GHG intensity
Large development potential which has been recognised internationally
Compared to competing technologies, has high flexibility & adaptability
partial retrofit, zero to full capture operation, with operation to match market conditions (reduces cost of energy penalty)
allows staged implementation - not possible with oxyfuel combustion
applicable to most stationary sources of CO2 emissions (expected to assist in development and increase learning rate)
Special synergies with renewable energy
Using solar heat for PCC sorbent regeneration can increase the uptake of renewables
Produces high purity CO2 (>99.7%)
Issues with Current PCC
Post combustion capture is presently only commercially used for capturing CO2 for enhanced oil recovery (EOR) and fertiliser (urea) production
There are important issues in applying the technology to coal fired boilers for the purpose of capture for storage
high cost (presently around $35/t CO2 captured and compressed, equivalent to around $33/MWh for an 85% reduction in GHG)
small scale (presently around 850 tpd/unit (suitable for 50 MWe))
adverse effects of NOx, SOx and fly ash trace elements on solvents
R&D programs focussed on reducing costs
both the cost of capture and the cost effects of NOx/SOx and trace elements for next generation PCC
PCC for natural gas turbines is required to achieve near zero emissions
PCC Research
Laboratory program on new
solid/liquid absorbents
Construction of a 3 t/day pilot rig
Partnership with industry for
LETDF demonstration of PCC at
10,000 t/day (proposal)
Partnership with industry
consortium on PCC from natural
gas turbine and sequestration in
coal strata
Removal of CO2 from
power station flue gases
Oxy-fired pulverised coal combustion technology
Oxy-Firing
PF fuel burned in high-purity oxygen atmosphere with flue gas recycling
Greatly increases CO2 concentration in flue gas
Only physical (not chemical) separation required to remove CO2 for storage
Issues
Challenging to retrofit
Air leaks add non-condensable contaminants (Ar, O2, N2)
High-purity O2 expensive and energy intensive
New air separation technologies can help here
Similar total energy cost as PCC (theoretical min. 104 kWh/tonne CO2)
Demonstration project
CS Energy (with CCSD) 30MW demonstration in Qld
Partnership with IHI
Coal Gasification
Gasification - A Key Technology
„Gasification is the key enabling technology required to
form the building blocks of 21st Century Energy Plants‟
(US DoE Vision 21, FutureGen)
IGCC (2005-2010) – ‗polygeneration‘ of power, chemicals,
hydrogen, liquid fuels. (IGCC = Integrated Gasification Combined Cycle)
NOx, SOx greatly reduced
Efficiency 45-50% achievable
IGFC (2015-2020) (IGFC = Integrated Gasification Fuel Cell)
―Zero Emission‖ technologies (2015-2030)
CO2 separation and sequestration
Hydrogen based energy systems
IGCC Technology
ChevronTexaco-2003
FEEDS GASIFICATION GAS CLEANUP END PRODUCTS
Alternatives:• Asphalt• Coal• Heavy Oil• Petroleum Coke• Orimulsion• Natural Gas• Wastes• Clean Fuels
Alternatives:• Hydrogen• Ammonia• Chemicals• Methanol
MarketableByproducts:
Sulfur
Gas & SteamTurbines
SulfurRemoval
Syngas
ElectricitySteam
Combined CyclePower Block
Byproducts:
Solids (slag)
Gasifier
Oxygen
Gasification Is Not New…
First commercial coal gasification plant was in London in
1812 for “town gas” - lighting, cooking and home heating
Gasification peaked in the U.S. in the 1930s with about
11,000 gasifiers consuming about 12 million tons/year coal
As natural gas availability increased, only coke oven gas
survived
Gasification Overview - 1940 to 1980
Modern gasification emerged in the 1930s with the
development of large scale air separation units for low cost
oxygen
Pressurised gasification systems for methane rich „town gas‟
and industrial syngas (CO and hydrogen)
Large, high pressure gasification systems for production of
liquid fuels and synthetic natural gas from coal in 1970‟s
Sasol still operates approx 90 Lurgi gasifiers for liquid fuels
production
Modern Gasifiers Improved in the 1980s
Use of gasification for power generation
emerges as a new opportunity
Commercial demonstration of high efficiency
IGCC began in the 1980‟s
Commercial gasifiers now all high-pressure, O2-
blown, entrained flow
All major technologies have demonstration
scale IGCC plants (≥250MW)
IGCC in the power industry
In chemicals & refinery industries, coal
gasification, and capture of CO2 from syngas
is commercially mature.
Without CO2 capture, the cost of electricity
from current IGCC is ~10-20% greater than
from mature PC plants (US, Source: EPRI).
Costs will be reduced with increased IGCC
commercial deployment.
Cost of Electricity with CO2 Capture
(US market)
Australian generation costs: 2-3c/kWh
Average price:~2.5-5(+) c/kWh (Source: NEMMCO, 2006 average)
Incremental cost of PC→IGCC greater in Australia than US
No NOx, SOx removal units
CO2 capture and storage (1st generation technology) approx doubles current generation costs
Some benefits with IGCC )
product flexibility
Lower efficiency penalty
Capture costs: IGCC—1.5cent/kWh, NGCC—2.0cent/kWh, SCPC—3.0cent/kWh
Source: Rosenberg, GTC 2005, based on estimates of EPRI & US EPA
Australian situation
Efficiency penalty of CCS
14% 29%
Recent GE Gasification Licenses in China
Source: GE Energy, China, 2006
Yueyang (Dongting) Sinopec-Shell
Coal Gasification Project
Gasifier at site – Sep 2005Source: Shell Gas and Power, 2006
Yueyang Sinopec-Shell Coal Gasification
Project (2)
Source: Shell Gas and Power, 2006
Gasification Research in Australia
High pressure, high temperature
coal conversion measurements
Fundamental investigations of
coal gasification reactions
Slag formation and flow
Technology performance models
Environmental issues
To improve the understanding of coal performance in gasification technologies, supporting:
• Marketing of Australian coals for new technologies
• Implementation of advanced clean coal technologies in Australia.
Coal gasification is a multi-stage process
Coal pyrolysis
Rapid volatile release
Determines char yield and morphology
Combustion
Limited, fast. O2 consumed early in process
Exothermic, provides heat for endothermic gasification reactions
Char Gasification
Slow, rate determining. Endothermic
CO2 and H2O converted to CO and H2.
Slag formation and flow
Flux may be required to achieve adequate viscosity
flux
O2
CO/CO2
slag
CO2 and H2O
CO + H2
Coal Gasification
Gasification Research Facility
Entrained Flow Reactor Pressurised TGA
High Pressure
Wire Mesh Reactor
High Temperature
Viscometer
High Pressure Entrained Flow Reactor (PEFR)
Entrained-flow reactor
Capable of 20 bar pressure, 1500°C wall temperature
Coal feed rate of 1-5 kg/hr
Gas mixtures of O2, CO2, H2O and N2
Adjustable sampling probe -char and gas samples collected at different residence times (0.5-3s)
Gas Analysis
Feeder
Preheating
and mixing
Three-section
reaction zone
Water quench
Sampling probe
and gas analysis
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Residence Time (s)
Co
nvers
ion
(%
)
CRC252
CRC263
CRC274
CRC298
CRC358
CRC281
Coal gasification behaviour
20 bar, 1400°C, 2.5% O2, C:O ~ 1:1
Char gasif‟n
0
1
2
3
4
5
6
7
0 20 40 60 80 100
Carbon Conversion (%)
Eq
uil
ibri
um
Gas C
om
po
sit
ion
(m
ol%
)Gasification conversion drives gas
phase composition
CRC274 – 1300°C, 5%O2
VM (daf) = 32.6%
CO
H2
CO2
steam
O2
Points = measured
Lines = eqbm
Char Gasification Process
1. Gas transport to external surface
• Very fast. Rate limiting at very high
temperatures
2. Reactant gas diffusion through pores
of char
• Complex (to measure and predict) –
contribution depends on size, length and
geometry of micro and meso pores
3. Reaction on char surface
• Heterogeneous reaction chemistry
• Multiple parallel reactions
4. Diffusion of reaction products
Carbon-Gas Reactions
Key issues:
Competing reactions
Complex kinetics
Rate controlling mechanism changes
with reaction conditions
Coal properties affect char reactivity
Cf + H2O C(O) + H2
C(O) CO + Cf
Cf + CO2 C(O) + CO
C(O) CO + Cf
Char-CO2:
Cf + H2 C(H2)
Char-H2O:
Interpreting rate measurements
Integration of low and high temperature
measurements
Identify kinetic regime for competing
reactions
First of a kind data for high pressure char/CO2
and char/steam reactions
Still need integration of gasification rate &
char structure during conversion
-20.0
-18.0
-16.0
-14.0
-12.0
-10.0
-8.0
-6.0
-4.0
0.00040 0.00050 0.00060 0.00070 0.00080 0.00090 0.00100
1/T (1/K)
ln(i
ntr
insic
rate
co
eff
icie
nt
(gm
-2s
-1b
ar-)
TGA data- CRC281 PEFR char
FBR data- CRC281 ref char
TGA data- CRC252 PEFR char
FBR data- CRC252 ref char
PEFR data- CRC281 PEFR char
PEFR data - CRC252 PEFR char
CRC281
CRC252
~900°C
~1400°C
Gasification modelling
Model needed for interrogation and application of measurements
Integration of fundamentals with system and technology models
relationships with international programs (REI, USA), Pilot and demo plant operators
Australia has no pilot or commercial scale gasification plant
Collaboration is essential to apply knowledge and to ‗validate‘ outcomes
Pilot scale test program planned for 2007 (Siemens, Germany)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0.0 0.5 1.0 1.5 2.0 2.5
Distance from reactor top (m)
Re
ac
tio
n r
ate
(k
g/k
g/s
)
0
10
20
30
40
50
60
70
80
Ca
rbo
n c
on
ve
rsio
n (
%)
C+O2 C+CO2 C+H2O Carbon conversion
Gas TParticle
flow
PEFR model
Slag Viscosity Testing
10
20
30
40
1300 1350 1400 1450 1500 1550
50
Maximum for
Slag Tappability
Tcv
Vis
co
sit
y P
a.s
Temperature 0C
100/0 Ash/CaCO3
100/10 Ash/CaCO3
100/20 Ash/CaCO3
Slag Viscosity
25 Pa s is the accepted maximum viscosity at the slag
tap for successful operation
Flux addition required if viscosity is too high
Temperature of Critical Viscosity
Slag becomes heterogeneous
Trouble-free tapping of slag is not possible
Syngas for
chemicals or
power
Towards Zero Emissions
steam
coalGasification
CO/H2Shift and
Gas
separation
H2O
oxygen
CO2
disposal
H2
power
combined
cycle
generation
Shift and CO2 separation „standard‟ practice in gasification for refinery and NH3 applications
Scale and cost issues being addressed for power applications
Optimum H2/syngas ratios changed as H2 market and CO2 capture requirements develop
Gas Cleaning, Processing and Separation
Low Pressure H2
Technology development:
Gas Processing & Separation
Key cost and efficiency drivers:
Increase temperature of gas cleaning and processing
Development and application of membrane separation systems
Integrate gas processing and separation stages with membrane reactors
Coal
Gasifier Gas
Cleaner
High T
Shift
Low T
Shift
Gas separation
H2
Cu
rren
t te
ch
no
log
y
CO2
Coal
Membrane
Shifter
H2
Mem
bra
ne
Re
ac
tor
CO2
CO+H2
CO2+H2
CO + H2O = CO2 +H2
Gas Cleaning, Processing and CO2/H2
Separation
Key enabling technologies for coal based H2
energy systems
Large scale, low cost processes essential
High temperature gas cleaning systems
Catalytic shift reactions
Membrane separation systems
Membrane reactors
Shift and separation in a single unit
CO2/H2 Separation – Novel membrane
systems
Amorphous metal membranes
Alloy design for high T, low cost H2 separation
Molten alloy ejected through nozzle onto copper wheel
Cooling rates up to 1010 Ks-1
30 µm amorphous metal membranes
H2/CO2 separation testing
H2
Applying the Research:
Collaboration and Investment Proposals (IGCC technologies)
4 Main Scales of Activity
Fundamental Research – gasification, gas processing, separation etc
Address technical barriers and concept limitations
Proof of Concept – testing with „real‟ coal syngas
~40kg/h cLET syngas generator
Proposed pilot scale work with international facilities (Germany, China …)
Pilot scale gasification facility (proposed)
Coal resource assessment and market support
Technology development scale
gas cleaning, shift reactor design, gas separation test modules, hydrogen production and use etc
Partnerships between energy, chemical, refinery industries
Zero emissions and enabling technologies
Hybrids, renewables etc
$60-100M program
Demonstration projects (proposed industry projects - LETDF)
IGCC – prove commercial and technical viability
Foundation for next generation technology
Link with CO2 storage demonstrations
>$500M program
Proposed Low Emissions Power Research
Infrastructure (up to ~5MWth)
Gasifier
Gas Cleaning
(Conventional)
Gas
Turbine
Clean
syngasGas
Shifting
CO2/H2
Separation
F-T
Synthesis
Liquid fuels
Power
CO2 DisposalH2
Fuel
Cell
Hot Gas
Cleaning
Backbone Facility
Coal
O2/H2O
Gasif’n R&D
H2 turbines etc
GTL etc
Gas sep’n
Biomass
Gasifier
= possible research project / ‗customer‘ & collaboration areas
• Lab scale fundamental R&D at research institutions.
• ‗backbone‘ facility to support R&D
• ‗Development‘ scale projects developed in partnerships
Future H2 uses
Advanced gas
cleaningRenewables
Looking Forward….
eg: Renewable/Fossil Fuel
Hybrid Technologies
Hybrid Solar/Fossil Fuel Technologies
Solar reforming of methane at pilot scale has been demonstrated
Fossil
Fuel (CH4)
Water
water
CO/H2/CO2 H2/CO2 H2 - fuel
CO2 for sequestration
• Fuel cells
• Gas turbines
• Cogeneration etc
CH4 + H2O + 250 KJ CO + 3H2
CO + H2O H2 + CO2 + 3 KJ
Solar
Thermal
Fuel
Reforming
Solar Thermal
Water Gas
Shift
Conversion
CO2
Recovery
Advanced
Power
Generation~
Solar energy stored in chemical form (25-30% embodied solar energy in product gas)
CSIRO National Solar Energy Centre
Opened 31 March 2006
Largest high-concentration solar array in the southern hemisphere
200 mirrors, 700 m2, >500kW
Flagship facility to attract international collaboration projects
SolarGas™
25% more energy than the natural gas input
SolarH2™
Synergies with coal systems being developed
Summary
Coal is Australia‟s largest commodity export earner
Australia is dependent on coal for 85% of its electricity needs
This is unlikely to change significantly in the near term
Australia currently has very low cost power
Demand is growing strongly
Greenhouse gas emissions are the central issue in addressing
Australia‟s energy needs
Gasification provides a high efficiency technology platform for
development of low emissions power systems
Development pathway for power, hydrogen & polygeneration systems
New research is being developed in niche areas where breakthroughs
are needed to enable low emissions coal based energy technologies to
be implemented economically
Power, chemicals, liquid fuels, hydrogen (syngas cleaning, processing, gas
separation)
Cost and scale are key drivers
Moving to Implementation.…
Vision and strategy for Clean Coal Technologies is strong and clear
Australian R&D capabilities established to support technology implementation
IGCC deployment is happening at commercial scale internationally
Opportunities for Australian R&D to contribute to future technology development
Clear action required to overcome local implementation barriers
Major national and international gov‟t/industry/research partnerships are being established to facilitate research development, demonstration and deployment
Coordination and „critical mass‟ are essential
