Combustion and beyond: Alternate reactive/energy systems
Hai WangUniversity of Southern California
7ISFS, July 11-15, 2011
Energy Usage – current and future
2010 International Energy Outlook / US DOE
17 TW
24 TW
Growth in Demand Comes from China
2010 International Energy Outlook / US DOE
But the 2010 IEA projection was quite inaccurate
Current Projection Looks Rather Gloomy
2010 International Energy Outlook / US DOE
Energy Usage and Resources• Current world energy usage rate is ~17 TW.
17 TW/6.7 billion people = 2.5 kW per person
• World energy demand is to increase by 40%, to 24 TW by 2035.
• Business-as-usual energy demand > 45 TW by the century end.1
• Fossil and fissile energy sources are finite2
– Oil: 1354 billion barrels/31 billion barrels/yr = ~40 years– Natural Gas: 187 trillion m3/3 trillion m3/yr = ~60 years– Coal: 909 billion short ton/2.5 billion short ton/yr = ~380 years– Nuclear fission (~ 50 years)
Uranium: ~11.5 million tonThorium: ~34.5 million ton
2010 International Energy Outlook / US DOE1. Intergovernmental Panel on Climate Change (IPCC), “Climate Change 2001: The Scientific Basis,” Cambridge University Press, Cambridge, UK (2001). 2. W.C. Sailor, “New Generation Nuclear Fission?” presented at the Aspen Global Change Institute meeting, Aspen, CO, July 2003.
Greatest Technological Achievements of the 20th Century
1. Electrification2. Automobile3. Airplane4. Water Supply and Distribution 5. Electronics6. Radio and Television7. Agricultural Mechanization8. Computers9. Telephone10. Air Conditioning and Refrigeration11. Highways12. Spacecraft13. Internet14. Imaging15. Household Appliances16. Health Technologies17. Petroleum and Petrochemical Tech18. Laser and Fiber Optics19. Nuclear Technologies20. High-Performance Materials
U.S. NAE
Greatest Technological Achievements of the 20th Century
1. Electrification2. Automobile3. Airplane4. Water Supply and Distribution 5. Electronics6. Radio and Television7. Agricultural Mechanization8. Computers9. Telephone10. Air Conditioning and Refrigeration11. Highways12. Spacecraft13. Internet14. Imaging15. Household Appliances16. Health Technologies17. Petroleum and Petrochemical Tech18. Laser and Fiber Optics19. Nuclear Technologies20. High-Performance Materials
U.S. NAE
Greatest Technological Achievements of the 20th Century
1. Electrification2. Automobile3. Airplane4. Water Supply and Distribution 5. Electronics6. Radio and Television7. Agricultural Mechanization8. Computers9. Telephone10. Air Conditioning and Refrigeration11. Highways12. Spacecraft13. Internet14. Imaging15. Household Appliances16. Health Technologies17. Petroleum and Petrochemical Tech18. Laser and Fiber Optics19. Nuclear Technologies20. High-Performance Materials
U.S. NAE
It’s all about combustion!
1. Make solar energy economical2. Provide energy from fusio3. Develop carbon sequestration methods4. Manage the nitrogen cycle5. Provide access to clean water6. Restore and improve urban infrastructure7. Advance health informatics 8. Engineer better medicines9. Reverse-engineer the brain10. Prevent nuclear terror11. Secure cyberspace12. Enhance virtual reality13. Advance personalized learning14. Engineer the tools of scientific discovery
NAE Grand Challenges of the 21th Century
1. Make solar energy economical2. Provide energy from fusion3. Develop carbon sequestration methods4. Manage the nitrogen cycle5. Provide access to clean water6. Restore and improve urban infrastructure7. Advance health informatics 8. Engineer better medicines9. Reverse-engineer the brain10. Prevent nuclear terror11. Secure cyberspace12. Enhance virtual reality13. Advance personalized learning14. Engineer the tools of scientific discovery
NAE Grand Challenges of the 21th Century
• The transition into a fossil-fuel depleted world presents great opportunities for combustion research.
• As a major driving force for 20th century achievement, combustion should continue to play a significant role in broader, renewable energy utilization.
Solar1.2 x 105 TW on Earth’s surface
36,000 TW on land
Biomass5-7 TW gross (world)0.29% efficiency for all cultivatable landnot used for food
Hydroelectric
Geothermal
Wind2-4 TW extractable
4.6 TW gross (world)1.6 TW technically feasible0.6 TW installed capacity 9.7 TW gross
Tide/Ocean Currents 2 TW gross
Renewable Resources
www.msd.anl.gov/events/colloquium/docs/GWC_Solar2_1-06.ppt
Areas where Combustion Can Help
• DirectBiomass – Biofuel combustion
• IndirectWind power – Carbon fibre
Light weight, high strength, cost
Solar – Photovoltaic thin filmsHigh efficiency & stability, cost
Energy storage – Li ion batteriesFast charging, good discharging rate, cost
Solar1.2 x 105 TW on Earth’s surface
36,000 TW on land
Solar Resources
17 TW/36,000 TW on land (world)/15% efficiency = 0.3% land
World land mass: 13,056 million hectares × 0.3% ~ 400,000 km2 (the size of Iraq)
Challenge for Solar Energy – cost, cost, cost !
Coal
Nat
ural
Gas
Nuc
lear
Win
d
Sola
r
Geo
ther
mal
Biom
ass
Hyd
ro
Conv
entio
nal
Adva
nced
with
CCS
Conv
entio
nal c
ombi
ned
cycl
e
Adva
nced
com
bine
d cy
cle
Adva
nced
com
bine
d cy
cle
w C
CS
Conv
entio
nal t
urbi
ne
Adva
nced
turb
ine
Ons
hore
Offs
hore
Phot
ovol
taic
Ther
mal
NREL Timeline of Solar Cell Efficiency
Dye-Sensitized Solar Cell (DSSC)• Michael Gratzel (1991)
Dye-Sensitized Solar Cell (DSSC)
S
electrolyte Transparent conducting glassTransparent conducting glass dyeTiO2
S*
h
ox (I3-) red (I-)
Redox mediator
e-e-
e-
-0.5
0.0
0.5
1.0
E (V)
maximumVoltage~0.75 V
Transparent glass/film
TCO
Transparent glass/filmTCO
Nanocrystalline TiO2 film
Pt catalyst
triiodideiodide
e-
e-
h
Transparent glass/film
TCO
Transparent glass/filmTCO
Nanocrystalline TiO2 film
Pt catalyst
triiodideiodide
e-
e-
h
Photoanode:Currently the most costly part in DSSCs
Photoanode and its Preparations
• Nanocrystalline TiO2 thin films (~10 m thickness)• Ideal particle size: 10-30 nm• Particles are single crystals• Anatase performs better (versus rutile)• Current technique for anode fabrication
– Commercial TiO2 powder (from combustion processes)– Making a paste/paint & screen printing– Sinter at 450 ◦C (glass substrate only)– For DSSC applications: Staining with a dye
Tubularburner
Shielding Ar
C2H4/O2/Ar
Synthesis Method – Premixed Stagnation FlameSynthesis Method – Premixed Stagnation Flame
Flame Stabilizer
TTIP
Carrier gas Ar
TTIP/Ar
Electric mantle
vO
vO
Tmax
burner-stabilized flame
Stagnation flame
Flame Structure (Ethylene-oxygen-argon, = 0.4)
3
4
5
6
7
8
9
10
11
2.7 2.8 2.9 3.0 3.1 3.2 3.3
"Pa
rtic
le"
Tim
e (m
s)
Distance from the Nozzle, x (cm)
Point of minimumgas velocity
po
ten
tia
l flo
w
reg
ion
pre
he
at
zon
e (0
.2 m
s)
nu
clea
tio
n/
gro
wth
re
gio
n(2
.2 m
s)
Flame sheet Stagnation surface
Computations used the Sandia counterflow flame code and USC Mech II
500
1000
1500
2000
2500
Stagnation surfaceT
(K
)
Particle nucleation/growth region
0
100
200
300
400
500
Ax
ial
Ve
loc
ity
v (c
m/s
)
Laminar flame speed
Particle nucleation/growth region
10-4
10-3
10-2
10-1
100
2.7 2.8 2.9 3.0 3.1 3.2 3.3
Mo
le F
rac
tio
n O2
C2H4
HH2
CO
H2O CO2
Distance from the Nozzle, x (cm)
12
11
61
5
, *avg
T , *avg
dTv
NkT dx
Burner nozzle
Motor
Rotating flame stabilizer
Cooling assembly
Burner nozzle
Motor
Rotating flame stabilizer
Cooling assembly
Flame Stabilized on Rotating Surface (FSRS)
•Particle synthesis and film deposition in a single-step
•Drastically reduced cost for film preparation
TTIP
Mesoporous film
TiO2 Vapor
Nanoparticles
Decomposition & oxidation
Nucleation, coagulation
Stagnation Flame Film PreparationShort growth time aided by thermophoresis
= small size + narrow distributions
Typical Synthesis Flames• Aerodynamically shaped nozzle (D = 1 cm) • Nozzle-to-disc distance (L = 3.4 cm)• Diameter of rotating disc 30.5 cm (0 to 600 RPM)
• 3.96%C2H4-26.53%O2-Ar, = 0.45, v0 = 302 cm/s• Adiabatic flame temperature = 2250 K• Laminar flame speed (calc) = 96 cm/s
• Flame diameter = 3 cm• Flame-to-disc distance = 0.29±0.03 cm• Measured maximum temperature = 2124 K
0
1
2
3
4
5
2 4 6 8 10 30
[dN
/dlo
gD
p]/
N
Particle Diameter, Dp (nm)
<Dp> = 9.8 nm
= 1.42
1070 PPM TTIP100 RPM
2 4 6 8 10 30
Particle Diameter, Dp (nm)
<Dp> = 8.8 nm
= 1.31
1070 PPM TTIP300 RPM
2 4 6 8 10 30
Particle Diameter, Dp (nm)
<Dp> = 8.5 nm
= 1.36
1070 PPM TTIP600 RPM
Particle Properties – Effect of Disc Rotation Speed
10 nm
rad = 300 RPM
306 PPM TTIP 1070 PPM TTIP
Particle Morphology & Film Properties
10 nm
rad = 300 RPM
306 PPM TTIP 1070 PPM TTIP
5 minute
14 m
Alumina substrate
@ 1070 ppm TTIP, 300 RPM
• Typically 5 m/min• Net deposition rate = ~ 1 m/sec• Film is highly porous but uniform
DSSC Performance
0
5
10
15
20
0
2
4
6
8
10
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Curr
ent D
ensi
ty, i
(mA
/cm
2 )
Pow
er D
ensi
ty, p
(W/c
m2 )
Voltage, V (V)
9% photoefficiency @ AM1.5
Combustion Issues • Large area deposition: Scale up a pseudo one-
dimensional premixed stagnation slot flame to several meters wide.
• The flame must be stable and never undergo extinction locally or globally.
• Heat release and management.
• Nanoparticle chemistry and transport in highly reacting flow.
• Flame aerosol kinetics and dynamics.