Coal Gasification Reactivity: Measurement and Application Measurement and Application David Harris CSIRO Energy Technology Research Program Leader, Low Emissions Technology Pittsburgh Coal Conference, September 2007 Johannesburg, South Africa
Coal Gasification Reactivity:Measurement and ApplicationMeasurement and Application
David HarrisCSIRO Energy TechnologyResearch Program Leader, Low Emissions TechnologyPittsburgh Coal Conference, September 2007 Johannesburg, South Africa
Outline
• The science and technology associated with coal gasification and its emergence as a key component in low emissions power technologies is very broad and complexis very broad and complex
• Many R&D programs aimed at technology development and demonstration• Objective of this presentation is to provide some insights into recent
research on one important aspect of coal use in gasification systems:p p g y• Coal gasification ‘reactivity’
• Research tools and capabilities to assist in technology development, implementation and optimisation
• Strategy of ‘deconstructing’ the gasification process• Provide flexible, fundamental knowledge and data to understand coal
behaviour in complex gasification systems• The use of model frameworks to ‘reconstruct’ the complex process• The use of model frameworks to reconstruct the complex process• Reduce the reliance on empirical, situation specific testing and develop
flexible, predictive capabilities• Understand the impact of coal type and reaction conditions on gasification
CSIRO. Coal Gasification Reactivity: Measurement and Application
processes
Research Team
• David Harris• Combustion and gasification reactionsCombustion and gasification reactions
• Daniel Roberts• Heterogeneous reaction kinetics
• John Stubington (University of NSW)• John Stubington (University of NSW)• Pyrolysis and thermal processing reactions, student leadership
• San Hla G ifi ti i d lli• Gasification conversion modelling
• Liz Hodge• PhD student, high temperature char/gas kinetics
CSIRO. Coal Gasification Reactivity: Measurement and Application
Key R&D Partnerships – Clean Coal Technologies
CSIRO Energy Technology’s work is fully embedded in collaborative initiatives. CSIRO is a key research provider for many research centres.
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 E T f d Fl hi
CSIRO. Coal Gasification Reactivity: Measurement and Application
CSIRO Energy Transformed Flagship• broad strategy – specific GHG targets
Low Emissions Power Generation
E
Post-combustion captureCapture ofEnergy
Conversion
ASU
Energy / Power
Capture of CO2
Capture ofCoal Energy
ASUOxy-fuel combustion
Storage/Usef COCO2
Coal
Pre-combustion decarbonisationEnergy /
Conversion of CO2
Gasification COShift
Energy / Power
or H2 / COCO2/H2
separationSyngas (CO+H2)
CSIRO. Coal Gasification Reactivity: Measurement and Application
Source: adapted from IEA Clean Coal Centre
Gasification based polygeneration processes
CSIRO. Coal Gasification Reactivity: Measurement and Application Source: US DoE Oak Ridge Laboratories – UT- Batelle
CSIRO R&D focus
Coal Gasification
CSIRO. Coal Gasification Reactivity: Measurement and Application
Gasification processes
• Gasification is a flexible core technology with many applications • Steelmaking
P• Power• Chemicals, liquid fuels production• Active carbon• Biomass utilisation …..
Gasification is the ke enabling technolog in f t re lo emissions• Gasification is the key enabling technology in future low emissions power and Hydrogen energy systems
• IGCC ‘polygeneration’ of power, chemicals and hydrogen, NOx, SOx greatly reducedG C ff• IGFC – increased efficiency
• “Zero Emission” technologies• CO2 separation and sequestration• Hydrogen based energy
• Current gasification research builds on a strong R&D base developed from extended use of combustion technologies
• Flash pyrolysis/hydrogenation (1970s)• Combustion kinetics, ash formation, gas cleaning (1970-1990s)
CSIRO. Coal Gasification Reactivity: Measurement and Application
Combustion kinetics, ash formation, gas cleaning (1970 1990s)• Coal gasification ‘reactivity’ (1980’s, 1990’s, current)
‘Strategic Science’ and Experimental Design
• Need to identify the appropriate issues• Isolate the issue from the processIsolate the issue from the process
• ‘Deconstruct’ the process• Practical coal and technology performance models need
flexible ‘fundamental’ data and understandingflexible fundamental data and understanding• ‘Reconstruct’ the system• Predictive rather than purely empirical capability • Not an academic ‘indulgence’• Not an academic indulgence
• Cooperation between industry, universities and research organisationsto ensure relevance
• Necessary depth and rigour through PhD and postdoc programs
• Its not all about simulating the industrial process!
CSIRO. Coal Gasification Reactivity: Measurement and Application
Gasification Research in AustraliaTo improve the understanding of coal performance in gasification technologies, supporting:
• Use of Australian coals in new technologies
• High pressure, high temperature coal i t
g• Implementation of advanced clean coal technologies in Australia.
conversion measurements• Effects of reaction conditions and coal type• Development of coal test procedures
• Fundamental investigations of coal• Fundamental investigations of coal gasification reactions
• Reaction mechanisms and kinetics, model development.
• Slag formation and flow for entrained-flow gasification
• Syngas cleaning & processing
CSIRO. Coal Gasification Reactivity: Measurement and Application
• Gas separation (H2/CO2)• Technology performance models
Coal Conversion in Gasification
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
ifi ti ti
O2
CO/CO2
gasification reactions
• Char Gasification• Slow, rate determining. Endothermic
CO d H O t d t CO d H
CO2 and H2O
CO + H2
• CO2 and H2O converted to CO and H2.
• Slag formation and flow• Flux may be required to achieve adequate
viscosity
CSIRO. Coal Gasification Reactivity: Measurement and Application
viscosity fluxslag
Interrogating the Gasification Process
PEFR I ti ti• Using laboratory-scale apparatus it is
PEFR: Investigating gasificationbehaviour under controlled and
possible to understand in some detail the important processes that combine to convert coal under gasification conditions.
O2
CO/CO2
Pilot testing – generating real gasification conditionsto test overall coal
co t o ed a dmeasurable conditions• Larger-scale testing allows us to test
how such information can be ‘recombined’ under process conditions, leading to a good knowledge of what
CO2 and H2O
CO + H2
to test overall coal performance
High pressure wire-mesh reactor:
happens in a gasifier.• This allows us to confidently assess
coals for specific gasification technologies, provide design g
Pyrolysis behaviour under high pressuresand high heating ratesChar gasification kinetics: high pressureTGA and fixed-bed reactorsSlag viscosity measurements
tec o og es, p o de des ginformation for gasifier construction, and a sound basis for troubleshooting gasification processes.
CSIRO. Coal Gasification Reactivity: Measurement and Application
fluxslagGas AnalysisTGA and fixed bed reactorsg y
Direct Measurement of CoalDirect Measurement of Coal Gasification Conversion
Behaviour
CSIRO. Coal Gasification Reactivity: Measurement and Application
High Pressure Entrained Flow Reactor (PEFR)
Feeder
Preheating and mixingg
Three-section reaction zone
• Capable of 20 bar pressure 1500°C wall
reaction zone
W t h• 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
Water quench
Sampling probe and gas analysis
CSIRO. Coal Gasification Reactivity: Measurement and Application
Adjustable sampling probe char and gas samples collected at different residence times (0.5-3s) Gas Analysis
Coal Conversion Rates20bar, 2.5% O2, C:O ~ 100%
100
%) (b) 1400°C
100
(%) CRC274(a) 1100°C
40
60
80
Con
vers
ion
(%
CRC252
CRC274
CRC298
CRC26340
60
80
Con
vers
ion CRC310
CRC299
CRC358
CRC281
Char conversion
ease
0
20
40
Car
bon
C CRC263
CRC358
0
20
40
Car
bon
C CRC281
Pet Coke
Vol
atile
rele
• Initial rapid conversion (up to 0.5s) is indicative of the contribution of devolatilisation
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Residence Time (s)
0.0 0.5 1.0 1.5 2.0 2.5 3.0Residence Time (s)
devolatilisation• Rate of increase of conversion following this is due to the influence of char
reactivity.• CRC310 has high volatile yields and low char reactivity• CRC281 has low VY but higher char reactivity
CSIRO. Coal Gasification Reactivity: Measurement and Application
• CRC281 has low VY but higher char reactivity• Note - conversion data is for complex reactant gas mixture – current work
considers individual reactants
Evaluation of Coal Gasification Behaviour
100
120
%) CRC274
60
80
cy' (
%)
CRC2741400°C, 2.5% O2
40
60
80
n Co
nver
sion
(% CRC298CRC299CRC281CRC252CRC263
40
60
tion
'Eff
icie
nc CRC298CRC281CRC299CRC252
0
20
40
Carb
on CRC263CRC358
1400°C, 2.5% O2
0
20
Gas
ifica
t
CRC263CRC358
0 50 100 150 200 250
Stoichiometry (%)
Trends expected due to increased amount of O available
0 50 100 150 200 250Stoichiometry (%)
• Trends expected, due to increased amount of O2 available• Higher volatile coals achieve greater conversion than lower volatile coals
• Exception is CRC299 – indicates that char reactivity is also significant (agrees with TGA testing of same coal suite)
CSIRO. Coal Gasification Reactivity: Measurement and Application
• Coals differentiated on the basis of different char reactivities
Gasification conversion drives gas phase composition
CRC274 – 1300°C, 5%O2VM (daf) = 32.6%6
7
(mol
%)
4
5
mpo
sitio
n (
COPoints = measuredLines = equilibrium
2
3
um G
as C
om
CO2
steam
O2
0
1
Equi
libri
u
H2
2
0 20 40 60 80 100
Carbon Conversion (%)• Demonstrates the strong effect of carbon conversion on CO/H2 in product gas
CSIRO. Coal Gasification Reactivity: Measurement and Application
• Earlier work (1atm) shows that when char gasification kinetics are known, we can ‘predict’ conversion (by different reactions) in complex flow system
Deconstructing theDeconstructing the Process: Char Structure and
R ti it
O2
CO/CO2
ReactivityCO2 and H2O
CO + H2
CSIRO. Coal Gasification Reactivity: Measurement and Application
fluxslag
Volatile Yield at Elevated Pressure
60% Open symbols = DTFCl d b l WMR
40%
50%
f coa
l (da
f)
AnthonyArendtGibbinsSuubergGriffin
60
al (d
af)
Coal C
Closed symbols = WMR
30%
40%
Yiel
d, w
t% o
f GriffinA (31.7%)B (34.8%)C (35.7%)D (36.2%)E (50 4%)
20
40
ld, w
t% o
f co
Coal B
20%0 10 20 30
Pyrolysis Pressure (atm)
E (50.4%)
00 5 10 15 20 25
Pyrolysis Pressure (atm)
Yie
• Volatile yield decreases with increasing pressure• Not correlated with Prox. VM• General agreement between wire mesh and high P drop tube results
CSIRO. Coal Gasification Reactivity: Measurement and Application
g g p• flow methods expensive and complex for volatile yield measurement,
difficult for volatiles and tar composition measurement
Carbon-Gas Reactions
Char-CO2: Char-H2O:
Cf + H2O C(O) + H2
C(O) → CO + Cf′
Cf + CO2 C(O) + CO
C(O) → CO + Cf′
Key issues:• Competing reactions
Cf + H2 → C(H2)
• Competing reactions • Complex kinetics• Rate controlling mechanism changes with
reaction conditions• Coal properties affect char reactivity
CSIRO. Coal Gasification Reactivity: Measurement and Application
Heterogeneous Reaction of Porous Particles
d
CO2
2CO CO + 1/2 O2 = CO2
Cg
CO2
I
0III
II
• More complex for full gasification system
Cs
CSIRO. Coal Gasification Reactivity: Measurement and Application
More complex for full gasification system• Multiple reactions – may be operating in different regimes
Reaction RegimesTemperatures where pf combustion & gasification technologies operate
R i II R i IRegime III Regime II Regime I
η =1Low-temperature ‘intrinsic’ measurements
1
measurements
η << 1 η < 0.5
1/T
CSIRO. Coal Gasification Reactivity: Measurement and Application
External mass transfer control
Chemical + porediffusion control
Chemical ratecontrol
Gasification Kinetic Models
• Two approaches to describing gasification kinetics at high pressuresp
• nth order rate equation, power law, ‘global’ rate expression• Langmuir-Hinshelwood rate expression
1 - nth order E ⎞⎛1 nth order• Approximation of multiple rate equations• valid over limited (defined) ranges of temperature, pressure etc.• Useful for integration of specific data into specific models
ng
ag P
RTEA ⋅⎟
⎠⎞
⎜⎝⎛ −= expρ
Useful for integration of specific data into specific models2 - Langmuir-Hinshelwood
• Derived from accepted rate equations for overall reaction• Therefore applicable generally over wider ranges of conditions• Therefore applicable generally over wider ranges of conditions• Useful for integrating chemical (intrinsic) kinetics into gasification
(and) process models.
CSIRO. Coal Gasification Reactivity: Measurement and Application
‘Intrinsic’ Reaction Kinetics at High Pressure
• High Reactant Pressures•Increasing reactant pressure increases rate but not infinitely
16
20
/s) x
10
5
H2O
rate, but not infinitely•Limits application of nth order rate equation over wide ranges of partial pressure
•Well-described by LH kinetics and ‘surface i ’ d l
4
8
12
Spec
ific
Rat
e (g
/g/
CO2saturation’ model
D G Roberts and D J Harris (2000). Char Gasification with O2, CO2 and H2O: Effects of Pressure on Intrinsic Reaction Kinetics, Energy & Fuels 14(2), 483-489.
00 10 20 30
Reactant Pressure (bar)
S
• Total Pressure Effect• ‘Dilution’ effect• Insignificant effect on ‘intrinsic’ low 3.E-05
4.E-05
5.E-05
e (g
/g/s
)
Char D
Char Y
Char B
CO2 = 5 atm
• Insignificant effect on intrinsic , low-temperature reaction kinetics
D G Roberts, D J Harris and T F Wall (2000). Total Pressure Effects on Chemical Reaction Rates of Chars in O2, CO2 and H2O F l 79(15) 1997 1998
1.E-05
2.E-05
Spec
ific
Rat
e
CSIRO. Coal Gasification Reactivity: Measurement and Application
H2O, Fuel 79(15), 1997-1998.0.E+00
0 10 20 30Total Pressure (bar)
Surface Effects at High Pressurem
p. (°
C) 1100
8002.0
2.5
ak A
rea 0.8
1.0(a) CO2
Tem
30 atm20 atm
500
800
0 5
1.0
1.5
Nor
mal
ised
TPD
Pea
0.2
0.4
0.6
Thet
a
TPD Peak
Des
orpt
ion
Rat
e
20 atm10 atm1 atm 0.0
0.5N
0.0
Theta
1.4
a 1 0
1.2
(b) H2O
0 1000 2000 3000 4000
Time (s)
D
0.6
0.8
1.0
1.2
lised
TPD
Pea
k A
rea
0.4
0.6
0.8
1.0
Thet
a
Temperature-programmed desorption 0.0
0.2
0.4
0 10 20 30 40
Reactant Pressure (bar)
Nor
ma
0.0
0.2TPD Peak
Theta
CSIRO. Coal Gasification Reactivity: Measurement and Application
D G Roberts and D J Harris (2006). A Kinetic Analysis of Coal Char Gasification Reactions at High Pressures, Energy & Fuels 20(6), 2314-2320.
( )
Competition Between Reactants
1. CO2 reaction intermediates effectively reduce the available active surface area for
22)]([][][ COtOHt OCCC −=
reduce the available active surface area for H2O reaction
2. LH kinetic model can be used, with a reduced available site concentration, to arrive at an ‘inhibited’ reaction rate
3. Net reaction rate is CO2 reaction plus the ‘inhibited’ H2O reaction
inhibited reaction rate
=1 MPa steam, 900°C= 0.5 MPa steam, 900°C
( )( ) ⎟
⎟⎠
⎞⎜⎜⎝
⎛
+−⋅+=
2
2
2231
31
11
CO
COOHCOmixture Pkk
Pkkρρρ
2=1 MPa steam, 850°C= 0.5 MPa steam, 850°C
Lines represent model calculations (i.e. ) mixtureρ
CSIRO. Coal Gasification Reactivity: Measurement and Application
D G Roberts and D J Harris (2007). Char Gasification in Mixtures of CO2 and H2O: Competition and Inhibition, Fuel, DOI:10.1016/j.fuel.2007.1003.1019.
Describing ‘Intrinsic’ Gasification Kinetics
• Utilisation of the reaction surface is key to application of kinetics
• Impacts on choice of kinetic model• Impacts on how reactivity data are applied to systems containing
more than one reactant• Langmuir-Hinshelwood Model works well over relevant ranges
of pressure• Works in pure gases and in mixtures of reactantsp g• Being tested at high pressure in presence of products• Still to be applied to high temperatures
CSIRO. Coal Gasification Reactivity: Measurement and Application
Application of Intrinsic Rate Data
T (K)
20 atm Pressure, 50% Reactants • Assumptions:
• Average pore size
-5
-3
s)
5000 2400 1400 1000 800
mass transfer limit
e age po e s e(5 nm) (measured)
• Rates normalisedto external surface area
-13
-11
-9
-7
Rat
e, g
/cm
2 /s
O O
area• Uniform particle
size (100 μm)• Single point in
b ff hi t
-19
-17
-15
13
ln(
CO2
H2O O2
burnoff history
0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40
1000/T (K-1)
• Need to be able to ‘predict’ rate at high T, P on basis of ‘intrinsic’ reactivity
CSIRO. Coal Gasification Reactivity: Measurement and Application
• Char physical structure (pore size, particle size, morphology…) key to high T reaction behaviour
Moving up the Arrhenius Curve: HighCurve: High Temperature Rates
sion
rate
) Regime IRegime IIRegime III
ln (c
onve
rs
~800-900°COver 1000°C ??Very high!
CSIRO. Coal Gasification Reactivity: Measurement and Application
Inverse Temperature
Can Char Structures be adequately Modelled?
High vol sub bituminous char Semi-anthracite char
• Need at least some reasoned correlations between coal and char types• Initial work with empirical correlations
CSIRO. Coal Gasification Reactivity: Measurement and Application
Classification of char types (high pressure chars)
80100
510
15
020406080
Perc
ent
Pressure (atm)
Gro
up I
Gro
up II
Gro
up II
I (atm)
• High pressure increases population of Group 1 (fluffy) chars
• Correlated to coal petrography
CSIRO. Coal Gasification Reactivity: Measurement and Application
Correlated to coal petrography• Impact on reactivity and modelling
Wu H, Bryant GW, Benfell KE, Wall TF. Energy Fuels 2000; 14:282.
High Temperature Ch /CO R tChar/CO2 Rate Measurements
CSIRO. Coal Gasification Reactivity: Measurement and Application
Gas Analysis
CO2/char reaction rate at ‘high’ temperature
Coal Whigh VM
Coal Ylow VM0 8
1.0
on
1400 °C1300 °C
20 bar total pressure, 5 bar CO2 partial pressure
high VMlow VM
0.6
0.8
al c
onve
rsi 1300 °C
1200 °C1100 °C
0.2
0.4
fract
iona
• PEFR operated with controlled gas atmospheres (fix PCO2, Ptotal, T, t), Char produced in-
0.0 1.0 2.0 3.0
residence time (s)
0.00.0 1.0 2.0 3.0
residence time (s)p g p ( 2, total, , ), p
situ • Conversion measured along length of reactor (t ≤ 3s)• Char samples taken for thorough analysis
• Morphology, structure, surface area pore size distribution…
CSIRO. Coal Gasification Reactivity: Measurement and Application
• ‘Intrinsic’ reactivity• Density and particle size
Char/CO2 reaction rates: Integration of intrinsic and ‘apparent’ rates
• Activation energy at high temperature ~ half that
20 bar total pressure, 5 bar CO2 partial pressure0
obtained at low temperature• Consistent with a transition
to ‘regime II’ at approximately 1373K)
-2
0
E ~100 kJ mol-1
approximately 1373K• First of a kind data for high
pressure char/CO2 and char/steam reactions
, g
g s-1
bar
-n)
-6
-4
• Still need integration of gasification rate & char structure during conversion
• topic of current PhD
ln (k
,
-10
-8 E ~200 kJ mol-1
• topic of current PhD program
10000/Particle Temperature (K-1)
6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5-12
CSIRO. Coal Gasification Reactivity: Measurement and Application
Understanding the high temperature system
• Regime 1 Kinetics• Lots of work has been done in understanding rates at highLots of work has been done in understanding rates at high
pressure• This research is ongoing….
• Diffusion theoryy• Well developed
• High temperature kinetics• Measurements presented hereMeasurements presented here
• Particle morphology and microstructure• Complicated and variable with conversion as well as reaction
conditionsconditions• How does all this come together in a gasification system?
• Traditionally used an ‘effectiveness factor’• How can this be used within the constraints of a complicated char
CSIRO. Coal Gasification Reactivity: Measurement and Application
• How can this be used within the constraints of a complicated char gasification system?
Measured and Calculated Pore Diffusion Effects (Combustion)
• Entrained Flow (Regime II) and Fixed bed (Regime I) data obtained at same conversion level
• Diffusion co-efficient measured directlydirectly
• small particles and f(T)• Intrinsic rate data can be
accurately extrapolated toaccurately extrapolated to practical temperatures
• Need to extend this approach to high temperature, high pressure gasification reaction systems
CSIRO. Coal Gasification Reactivity: Measurement and Application (Harris, Valix et al 1992)
Reconstructing the Process: Modelling of Flow ReactorsModelling of Flow Reactors
CSIRO. Coal Gasification Reactivity: Measurement and Application
Model validation: application to PEFR experimental program
vers
ion
(%)
60
80
100
ol%
)
2.0
3.0CRC-358 (Expt)CRC-274 (Expt)CRC-252 (Expt) CRC-358 (Model)CRC-274 (Model) CRC-252 (Model)
6 (a)
Car
bon
conv
0
20
40 CRC-358 (Expt) CRC-274 (Expt) CRC-252 (Expt) CRC-358 (Model)CRC-274 (Model)CRC-252 (Model)
6 (b)
CO
2 (m
0.0
1.0
Distance from reactor top (m)
0.0 0.5 1.0 1.5 2.0
5.0
6.0
7.0CRC-358 (Expt)CRC-274 (Expt)CRC-252 (Expt)CRC-358 (Model) CRC-274 (Model)CRC-252 (Model)
3.0
CRC-358 (Expt)CRC-274 (Expt)CRC-252 (Expt) CRC-358 (Model)CRC-274 (Model) CRC-252 (Model)
Distance from reactor top (m)
0.0 0.5 1.0 1.5 2.00.0
CO
(mol
%)
1.0
2.0
3.0
4.0
H2
(mol
%)
1.0
2.0
• Model calculations differentiate between initial rapid devolatilisation/combustion processes and the slower char gasification.
6 (c)
Distance from reactor top (m)
0.0 0.5 1.0 1.5 2.00.0
1.06 (d)
Distance from reactor top (m)0.0 0.5 1.0 1.5 2.0
0.0
CSIRO. Coal Gasification Reactivity: Measurement and Application
• Model is able to predict well the profile of carbon conversion and gas composition for different types of Australian coals.
• Still need to ‘overlay’ char surface area and structure dataHla, Harris & Roberts, 5th International Conference on CFD in the Process Industries - December 2006
Gasification modelling
0.80.9
s) 70
80
%)
C+O2 C+CO2 C+H2O Carbon conversion
0.30.40.50.60.7
ion
rate
(kg/
kg/s
30
40
50
60
on c
onve
rsio
n (%
Gas TParticle flow
0.00.10.20.3
0.0 0.5 1.0 1.5 2.0 2.5
Di t f t t ( )
Rea
cti
0
10
20
Car
bo Gas T flow
• Model needed for interrogation and application of measurements• Integration of fundamentals with system and technology models
Distance from reactor top (m)
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
CSIRO. Coal Gasification Reactivity: Measurement and Application
• Collaboration is essential to apply knowledge and to ‘validate’ outcomes• Pilot scale test program conducted August 2007 (Siemens, Germany)
Where are we now?
• Benchmark experimental data have been obtained on the gasification performance of a wide range of Australian coals at high pressures and temperatures
• There are clear effects of volatile yield and char gasification reactivity on gasification performance
• The rate of the heterogeneous char gasification reactions is critical in• The rate of the heterogeneous char gasification reactions is critical in determining coal conversion levels.
• Gas phase composition can be relatively well understood using equilibrium considerations. However…
• Conversion rate drives the gas phase reactions• Fundamental kinetic data for important char gasification reactions at
are now emerging for application at appropriate reaction conditions. d d f th d l t f di ti d l th t b d f l• needed for the development of predictive models that can be used for coal
and technology assessment.• Current work is producing data under conditions where coal/char-specific
processes (e.g. char reaction rates) can be separated and interpreted and
CSIRO. Coal Gasification Reactivity: Measurement and Application
re-constructed to produce an overall gasification conversion model
What is required?
• Reliable kinetic measurements need to be extended to all key reactions at elevated pressure
• Product inhibition competing/parallel reactionsProduct inhibition, competing/parallel reactions• Char surface area and porosity development
• Still need measurements of rate and structure from high T, P conditions l i i i d ifi ito apply intrinsic rate data to gasification systems
• Missing links and challenges!• Ability to predict:• Ability to predict:
• Volatile yield and char structure from high pressure pyrolysis • Char structure and morphology evolution during gasification
Need to apply to pilot and practical systems• Need to apply to pilot and practical systems • Models validated for simple flow system • First pilot scale trial program now complete for a well characterised set of
Australian coals
CSIRO. Coal Gasification Reactivity: Measurement and Application
• Are issues that differentiate coals in the laboratory significant at practical scale?
CSIRO Energy TechnologyCSIRO Energy TechnologyDr David HarrisResearch Program Leader,Low Emissions Technology
Phone: +61 (7) 3327 4617Email: [email protected]: www.csiro.au/science/energy
Thank youThank you
Contact UsPhone: 1300 363 400 or +61 3 9545 2176
Email: [email protected] Web: www.csiro.au