Combustion and beyond: Alternate reactive/energy systems

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


But the 2010 IEA projection was quite inaccurate

Current Projection Looks Rather Gloomy


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



U.S. NAE



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

http://upload.wikimedia.org/wikipedia/en/a/a4/PVeff%28rev110707%29d.png

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


<Dp> = 8.8 nm

= 1.31


2 4 6 8 10 30


<Dp> = 8.5 nm

= 1.36


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.

Documents

Combustion and beyond: Alternate reactive/energy systems