ACPS2008Sydney Convention Centre19-23 Oct 200819-23 Oct 2008
Alternative pathway to low emissions electricity - challenges for coal preparation
Louis WibberleyPrincipal Technologist
www.csiro.auCSIRO Energy Technology
Content
1. Issues with the current approach to low emissions electricity
2. An alternative approach
3 K bli t h l i3. Key enabling technologies
4. Coal specifications and coal preparation challengeschallenges
2
Current approach Clean Coal TechClean Coal Tech
Based on clean coal CCSCCS
d el
ect
technologies to reduce the cost of next generation, clean coal
O2
deliv
ered
g ,plants with CO2 capture and storage
CO
ASC-PCC, IGCC, oxy-pf 2010 2015 2020 2025 2030
Base plant CCS Trans Distrib Delivered
COE $/MWh $40 $45 $10 $25 $120
η(wet cooled) 43% -8% -2% -2% 31%
η(dry cooled) 41% -8% -2% -2% 29%
Delivered electricity from supercritical pf with CCS, 2015
CO2 capture - efficiency challenge for Clean Coal TechnologiesTechnologies
with capturewith capture
70%
80%H
V)
- 50 years
50%
60%
red
(%, H
50 years
30%
40%
cy, d
eliv
er
CCTCCT
10%
20%
Effic
ienc
0%1800 1850 1900 1950 2000 2050
Issues with clean coal technologies
High efficiency can only be achieved through very large plants (large capital steps)
transmission and distribution losses reduce fuel cycle efficiency by up to 4% and increase COE by up to $35/MWhup to 4% and increase COE by up to $35/MWh
Future CCS will have large energy penalty - around 20% of the power from new plant (which produces more CO2)p p ( p 2)
approximately doubles the cost of power production
penalties greater for old plant
Water cooling – increasing issue, CCS increases this
Low overall efficiency increases the amount of CO2 to be y 2stored – requires access to larger reservoirs
higher efficiency plants could delay the need for CCS, and extend th lif f t ithe life of storage reservoirs
Attributes for an alternative pathway
High thermal efficiency at smaller unit capacity
Increased adaptabilitycan adapt to CCS with less impact on efficiency and cost
suitable for dry climates – reduced fresh water/easier to dry cool
development potential - maintaining options, energy security
Increased flexibilityshorter startup time, high efficiency at part load … and in hot weather
Cost competitive and acceptable technology risksmaller units mean economies of scale must be achieved through
lti l itmultiple units
priorities dictate a pathway based on existing (or near term) technologies – at least in the short termg
Higher efficiency the key
Increased efficiency
Less CO2 produced
Less CO2 to be captured
Less extra CO2 from capture
Less CO2 to be stored
Current fuel cycle efficiency for deliveredelectricityelectricity
70
LSD low speed diesel engineMSD med speed diesel engineCCGT combined cycle gas turbine
60
70)
y gGT open cycle gas turbineIGCC integrated gasification
combined cyclePF advanced pf
50
60
cy (%
HH
V
CCGT
LSD
40al e
ffici
enc
PFGT
MSD
IGCC
30
Ther
m
Centralised
201 10 100 1000
DistributedDecentralised
Centralised
1 10 100 1000Unit capacity (MW)
2030 fuel cycle efficiency for deliveredelectricityelectricity
70
DCFC direct carbon fuel cellLSD low speed diesel engineMSD med speed diesel engineCCGT combined cycle gas turbine
60
70H
V) LSD
DCFC GT open cycle gas turbineIGCC integrated gasification
combined cyclePF advanced pf
50
ency
(% H
H
CCGTLSD
MSD
IGCC
40
rmal
effi
cie
PFGT
30Ther
DistributedDecentralised
Centralised
201 10 100 1000
Unit capacity (MW)
Distributed
Step change in thermal efficiency
The most efficient means for converting fuel energy to electricity is via internal combustion heat engines and fuel cells
C l ld hi t i i th l ffi iCoal could achieve a step increase in thermal efficiency using
Direct injection coal engines (DICE)Direct injection coal engines (DICE)
Direct fired gas turbines (DFGT)
Direct carbon fuel cell (DCFC)( )
Over 47% thermal efficiency should be possible with CO2capture now, and over 65% in the future
All require efficient production of ultra clean coals
Proposed alternative technology pathwaypathway
Ultra clean coalsUltra clean coals
DICEDICE
tric
ity Clean Coal Technologies
renewablesrenewables
ed e
lect
DCFCDCFC
deliv
ere
Extreme Coal Technologies
CCSCCS
CO
2fo
r C
2010 2015 2020 2025 2030
Paradigm shift
Dirty Clean
Pf fuel cycleRaw coal Electricity
IGCC fuel cycleRaw coal Electricity
Direct fired coal fuel cycleRaw coal Electricity
12Advanced coal processing –physical and chemical
Component technology #1
Ultra Clean Coal Water Fuels
Coal water fuels
Approx 8 Mtpa globally
Typically 30% water
Highly stable, with 12-24 th t ibl imonths storage possible in
unstirred tanks
Bingham viscosity - pasteBingham viscosity - paste when stationary, but thins rapidly with shear
Readily pumpable
For DICE would be micronised20 d dil t d t 45 t%-20µm, and diluted to ~45 wt%
solids before injection
Component technology #2
Adaptation of the low speed p pdiesel engine
Direct injection coal engine
Thermal efficiency of 54% HHV achievable at 100MW l b l d i i100MW scale by low speed marine engines
Coal should be able to achieve a fuel cycle efficiency of 50% (sent out basis)efficiency of 50% (sent out basis)
Coal has been used in diesel engines, mostly by injecting as a coal-water slurryy y j g y
water has negligible effect on thermal efficiency
technical issues of injection and wear mostly addressed in DOE studies (1978-94)
Highly flexible and adaptableeasily cooled, rapid start, waste heat sufficient to energise CO2 capture
UCC Energy undertaking small scaleUCC Energy undertaking small scale demonstration of UCC under APP program
Large diesel engine
Coal engine status
USDOE programs developed “acceptable” technologies for fuel handling, injection and engine management
Although USDOE programs of 1970-80s very successful, no i l ti d t kcommercial operation was undertaken
development terminated due to persistently low oil price
N d f l d t ti d i i lNeed for larger demonstration under semi-commercial conditions remains
large 2-stroke engines most suitable (30-97 MW)large 2 stroke engines most suitable (30 97 MW)
strong interest by large engine manufacturers to participate
Uncertain coal specifications for modern large enginesUncertain coal specifications for modern large enginesadapted from HFO or designed specially for coal
Uncertainty around engine designs to better optimise useUncertainty around engine designs to better optimise use of ultra clean coal water fuels
What has changed from 1980s?
1. Mounting pressure for HFO replacement … not just for diesel
2. New drivers mean willing to pay more for thermal ffi i ( d l t ti fl ibilit t )efficiency (and lower water consumption, flexibility etc)
3. Advances in physical and chemical cleaning of coal (and more to come)(and more to come)
4. Advances in ultra fine milling – lower energy and cost
5 New materials for engine components ceramics and5. New materials for engine components – ceramics and coatings
6. Increase in available engine size and efficiency6. Increase in available engine size and efficiency
7. Advances in engine control - all electronic systems give improved efficiency and emissions
Component technology #3
High penetration renewablesg p
High penetration renewables
Wind and solar have issues with short & long term energy storage
short term storage doubles cost, long term is impracticalterm is impractical
Inefficient use of biomass fuels in small dedicated plants
Spinning reserve Backup
p
Extreme Coal Technologies could be used to underpin the
fEfficientuse of Grid
development of renewables
DICE could provide efficient and cost effective spinning reserve
use of biofuels support
cost effective spinning reserve, long term backup, a means to efficiently use local biomass fuels ( h l ) d id t(char, algae) and grid support
Component technology #4
Direct carbon fuel cells
Direct carbon fuel cell
High thermal efficiencyg yover 90% (theoretical)
Extremely high efficiencyExtremely high efficiency achieved with UCC coal sample
Many configurations proposedsolid and liquid electrolytes
Currently at the laboratory and small pilot scale
Expect to be available for commercial generation by 2030commercial generation by 2030
giving >65% efficiency with CCS
One of many configurations
Component technology #5
CO2 capture and storage2 p g
CO2 capture and storage
Even at 100% efficiency, coal can only match gas
some CCS will eventually be required for fossil fuelled stationary power generationfuelled stationary power generation
R&D required to optimise capture from DICE and DCFC
DICE exhaust between pf and GTcapture using waste heat integrationp g g
DCFC flue gas similar to oxy-pf“capture” would not be requiredcapture would not be required
Potential to reduce energy penalty to 35% of that for Clean Coal Technologies
CO2 capture – less impact for Xtreme Coal TechnologiesTechnologies
with capturewith capture
70%
80%H
V)DCFCDCFC
50%
60%
red
(%, H
DICEDICE
30%
40%
cy, d
eliv
er
CCTCCT
10%
20%
Effic
ienc
0%1800 1850 1900 1950 2000 2050
CSIRO Extreme Coal Program – heat engine
System benefitsSystem benefits
additivesunderpinning renewables
Advanced coal processing
additivesrenewables
physical Coal-engine interactions
integrated emissions chemical
Atomisation/combustion
VM/char/ash/additives
control chemical /combustion additives
Advanced coal processing
Optimising between 5
Hypothetical cost curves
physical and chemical cleaning
N l h t4
5
(0.5
% a
sh)
OverallNovel approaches to physical separation
moisture and fines in
3
ost
$/G
J (
Stage 2 - Chemicalmoisture and fines in product are OK
magnetite carry over and ceramic mill media
1
2
oces
sing
co
ceramic mill media debris may not be OK
CSIRO program to 0
0 2 4 6 8 10 12Pr
o Stage 1 - Physical
p gdevelop super clean coals or “SuperCoal” using physical cleaning
Ash content after physical cleaning or before chemical cleaning (%, db)
using physical cleaning
Coal-engine interactions
Behaviour of coal under simulated engine conditions atomisation and combustion at 12-20Mpa and 1400-1800°C
Volatiles enhancementfunction of maceral content, grind, injection conditions, additives
Char morphology and burnoutlacy, cenosphere, coherent, burnout kinetics, effect on flyash
Behaviour and fate of residual mineral matterinfluence of occurrence in different coal macerals, cylinder conditions, interaction with trace inorganics and other fuels
Morphology of flyashMorphology of flyashsize distribution, particle shape, hardness
Effect of micronising mill type and grindEffect of micronising – mill type and grind
Nominal coal specifications for 1-5MW engines (larger engines may be more relaxed)(larger engines may be more relaxed)
Property Ideal Comments
Ash <1% Uncertain effects, up to 3% was deemedacceptable, likely to be strongly affected by mineral occurrence, char burnout, atomisation, engine materials and designengine materials and design
VM >25% Wide range used, uncertain VM enhancement factors
Fl h S h i l W lik l t b hi h t f h d lFlyash Spherical Wear likely to be highest for hard angular particles in 10 – 30µm range
Grind D90 <20µm Probably OK to 50µm for high VM coal
Sulphur As for pf Above 0.5% FGD likely
Alkalis No data Turbo charger and waste heat recovery temps <450ºC, spheroidisation of flyashp y
AFT No data Slagging unlikely due to low metal temps and cycling
Extrapolations from USDOE work over 1978-94
Final comments
UCCsUCCs1. There is an alternative pathway for low emissionsUCCsUCCs
DICEDICE
coal-based electricity using direct fired internal combustion engines initially, and then carbon fuel cells
cost effectively underpins a high penetration of renewablesDICEDICE
renewablesrenewables
cost effectively underpins a high penetration of renewables
50% reduction in CO2 intensity possible without capture
2 Further reduction in CO intensity could be achievedDCFCDCFC
2. Further reduction in CO2 intensity could be achieved with a marked reduction in storage required over that for current clean coal technologies
CCSCCS3. Requires efficient production of ultra clean coals
4. Advanced coal preparation is required to minimise fuel cost and to maximise cycle greenhouse gas benefits
2010 2015 2020 2025 2030
Energy TechnologyName Louis WibberleyTitle Principal TechnologistPhone 61 2 4960 6050Email [email protected] www csiro au/detWeb www.csiro.au/det
Thank You
Phone 1300 363 40061 3 9545 2176+61 3 9545 2176
Email [email protected] www.csiro.au
www.csiro.au