sustainable fossil fuels?
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Sustainable Fossil Fuels?
Klaus S. LacknerColumbia University
April 2004
World Needs Low Cost Energy
100
500
1000
5000
10,000
20,000
50,000
200
2000
0.01 0.10 1.0 10 100
Mean Power Consumption Per Capita, kW/person
Mean Gross Domestic Product Per Capita ($/yr
•person)
Bangladesh
China
MexicoPoland
South KoreaU.S.S.R.
France
Japan
U.K.U.S.A.
SLOPE = 23¢/kW•hr
AFFLUENCE
POVERTY
Fossil Energy contributes 80 to 90% of the total World
Energy
Cannot eliminate the
biggest resource from
the world market10 billion people trying to consume energy as US
citizens do today would raise world energy demand 10 fold
Fossil Fuels VitalFor World Economy
Natural Gas22%
Coal25%
Petroleum39%
HydroElectric7%
Solar1%
Nuclear6%
… but this does not make them sustainable
150
200
250
300
350
-400000 -300000 -200000 -100000 0
Age (years)
0
-10
-8
-6
-4
-2
+2
+4
Petit et al., Nature 399
Vostok, Antarctica Ice Core data
Te
mp
era
ture
Ch
an
ge
s (ºC)
CO
2 (p
pmV
)
Industrial age CO2 increase
Anthropogenic increase of carbon dioxide is well documented for 20th century.
Changes in the industrial age are large on a geological scale
Fossil Carbon Accumulates in the AirCO2 increase in the atmosphere accounts for 58% of all fossil CO2 emissions
0 Gt
8,000 Gt
7,000 Gt
6,000 Gt
5,000 Gt
4,000 Gt
3,000 Gt
2,000 Gt
1,000 Gt
21st Century’s Emissions
???
Atmo-spher
e2000
Ocean
Plants
Coal
Oil, Gas, Tars & Shales
Methane Hydrate
s
pH < 0.3
39,000 Gt
20th Century
50,000
Gt
???
Soil & Detritus
1800 constant
23
4
Scales of Potential Carbon
Sinks
Carbon Resources
Carbon Sources and Sinks
20th Century
The Mismatch in Carbon Sources and Sinks
43
1
2
5
1800-
2000
Fossil Carbon Consumption to
date
180ppmincrease in
the air 30% ofthe Oceanacidified
30% increase inSoil Carbon
50%increase
inbiomass
Hydrogen economy cannot run on electricity
There are no hydrogen wellsPrice Ranges for Raw
Fossil Energy Resources
$0.00
$5.00
$10.00
$15.00
$20.00
$25.00
$30.00
Coal Gas Oil Electricity
Price per GJ
Tar, coal, shale and biomass could support a hydrogen economy.
Wind, photovoltaics and nuclear energy cannot.
Net Zero Carbon EconomyNet Zero Carbon Economy
CO2
extraction from air
Permanent & safe disposal
CO2 from concentrated
sources
electricity or hydrogen
Mineral carbonate disposal
Capture of distributed emissions
Sustainability
A technology or process is sustainable at a specific scale and for a specific time,if no intended or unintended consequences will force a premature abandonment
Private SectorCarbonExtracti
on
CarbonSequestratio
n
Farming, Manufacturing, Service, etc.
Certified Carbon Accounting
certificates
certification
Public Institutionsand Government
Carbon Board
guidance
Permits
&
Credits
CO2
extraction from air
Permanent & safe disposal
CO2 from concentrated
sources
Net Zero Carbon EconomyNet Zero Carbon Economy
Lake Michigan
21st century carbon dioxide emissions could exceed the mass of water in Lake Michigan
Short Term Answers Enhanced Oil Recovery Coal Bed Methane Extraction Injection into abandoned wells Injection into deep saline
reservoirs
Ultimately carbonic acid must be neutralized
Constraints on Disposal Methods
Safe Disposal Minimum Environmental Impact No Legacy for Future Generations Permanent and Complete
Solution Economic Viability
5000 Gt of C
200 years at 4 times current rates of emission
Storage
Slow Leak (0.1%/yr)
5 Gt/yr for 1000 years
Current Emissions: 6Gt/year
Economically tolerable: 1 cent/kWh $20/t of CO2
Nuclear Energy Limit: $60/t of CO2
$10/ton of CO2: 8.5¢/gallon
Fast leaks are catastrophic (Lake Nyos)Slow leaks cause greenhouse emissions
Dilution causes irrevocable change
Energy States of Carbon
Carbon
Carbon Dioxide
Carbonate
400 kJ/mole
60...180 kJ/mole
The ground state of carbon is a mineral
carbonate
Net Carbonation Reaction for Serpentine
Mg3Si2O5(OH)4 + 3CO2(g) 3MgCO3 + 2SiO2 +2H2O(l)
heat/mol CO2 = -63.6 kJ
Accelerated from 100,000 years to 30 minutes
Peridotite and Serpentinite Ore Bodies
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Magnesium resources that far exceed world fossil fuel supplies
Rockville Quarry
1 GW Electricity1 GW Electricity
~35 kt/day
ZECA ProcessZECA Process
~1.4 kt/day Fe ~0.2 kt/day Ni, Cr, Mn
4.3 kt/day
Heat
Coal
Sand & Magnesite
Open Pit Serpentine Mine
Open Pit Serpentine Mine
CO2
11 ktons/day
Coal StripMine
Coal StripMine
Zero Emission Zero Emission Coal Power PlantCoal Power Plant
70% Efficiency
Zero Emission Zero Emission Coal Power PlantCoal Power Plant
70% EfficiencyEarth Moving ~40 kt/day Mineral Mineral Carbonation Carbonation
PlantPlant
Mineral Mineral Carbonation Carbonation
PlantPlant28 kt/day36% MgO
Mining, crushing & grinding: $7/t CO2 — Processing: $10/t CO2 — No credit for byproducts
Serpentine and Olivineare decomposed by acids
Carbonic Acid - Requires Pretreatment
Chromic Acid Sulfuric Acid, Bisulfates Oxalic Acid Citric Acid …
ALBANY’S SUCCESS
200,000 years reduced to 30 minutes
W.K. O’Conner, D.C. Dahlin, D. N. Nilsen, R. P. Walters & P.C. Turner
Albany Research Center, Albany OR
Suggests simple cost-effective implementation
Mg3Si2O5(OH)4+3CO2(g) 3MgCO3+2SiO2+2H2O(l)
Acid Recovery: Solvay Process Neutralize with ammonia Recover through heating
CO2
extraction from air
Permanent & safe disposal
CO2 from concentrated
sources
Net Zero Carbon EconomyNet Zero Carbon Economy
CO2 N2
H2OSOx, NOx and
other Pollutants
Carbon
Air
Zero Emission Principle
Solid Waste
Need better sources of oxygen
Power Plant
CaO as an enthalpy carrier
CaCO3 + heat CaO + CO2
O2 + 2H2 2H2O + 571.7 kJ
CaO + C + 2H2O 2H2 + CaCO3 + 0.6 kJ
C + O2 CO2 + 393.5 kJ
Compare to392.9 kJOutput
178.8 kJ
Zero Emission CoalCO2
H2OH2O H2O
H2O
H2O
CO2
CO2
CaCO3
CaO
H2H2
H2
CH4, H2O
Air
N2
Coal Slurry
GasifierDe-
carbonizer CalcinerFuel Cell
Gas Cleanup
Polishing Step
Ash
Cleanup
CaO + C + 2H2O CaCO3 + 2H2
Lime/Limestone Cycle
Heat
Closed Cycle for Gas
CO2
extraction from air
Permanent & safe disposal
CO2 from concentrated
sources
Net Zero Carbon EconomyNet Zero Carbon Economy
Air Flow
Ca(OH)2 solution
CO2 diffusion
CO2 mass transfer is limited by diffusion in air boundary layer
Ca(OH)2 as an absorbent
CaCO3 precipitate
CO2
1 m3of Air
40 moles of gas, 1.16 kg
wind speed 6 m/s
0.015 moles of CO2
produced by 10,000 J of gasoline
220J2mv=
Volumes are drawn to scale
Wind area that carries 22 tons of CO2 per year
Wind area that carries 10 kW
0.2 m 2
for CO2 80 m 2
for Wind Energy
How much wind? (6m/sec)
Biomass
3 W/m2
Sunshine
200 W/m2
Wind Energyv = 6m/s130 W/m2
Extraction from Air
Power Equivalent
from gasoline
v = 6 m/s
60,000 W/m2
Areas are drawn to scale
60m by 50m
3kg of CO2 per second
90,000 tons per year
4,000 people or
15,000 cars
Would feed EOR for 800 barrels a day.
250,000 units for worldwide CO2 emissions
Boundary Layer
Wind Energy - CO2 Collection
Wind Energy • Convection tower,
Wind Mill etc.
• Extract kinetic energy
• Wind Turbines
• 30% extraction efficiency
• Throughput130W/m2 @ 6m/s wind
• Cost$0.05/kWh
CO2 Collection
• Convection tower, absorbing “leaves”, etc.
• Extract CO2
• Sorbent Filters
• 30% extraction efficiency
• Throughput0.64g/(s·m2) @ 6m/s wind
• Cost by analogy$0.50/ton of CO2
Additional Cost in Sorbent Recovery
A First Attempt
Air contactor:2Na(OH) + CO2 Na2 CO3
Calciner:CaCO3CaO+CO
2
Ion exchanger:Na2CO3 + Ca(OH)2 2Na(OH) + CaCO3
Objections CO2 in air is too dilute
Cross section of structure is affordable Binding energy of sorbent scales
logarithmically G = RT log P/P0
Liquid absorbers will saturate Energy consumption diverges Cost of sorbent recovery
CaCO3+ 180 kJ CaO + CO2
CaO + H2O Ca(OH)2 + 65 kJ
15 km3/day of air
As electricity producer the tower generates 3-4MWe
As electricity producer the tower generates 3-4MWe
15 km3/day of air
9,500t of CO2 pass through the tower daily.
Half of it could be collected
9,500t of CO2 pass through the tower daily.
Half of it could be collected
300m
115m
Cross section 10,000 m2
air fall velocity ~15m/s
Water sprayed into the air at the top of the tower cools the air and generates a downdraft.
Any design that moves air can be used for CO2capture
Cooling Tower Design
Diameter ratio of smoke stack to capture tower is 3001/2
=17
Exotic Designs
Process Schematic
Capture Device
Trona Process
Limestone Precipitate
Dryer
Fluidized Bed
Hydroxylation Reactor
CombinedCombustion-Separation
(1)
(2) (3)(6)
(5)
Solid Oxide Membrane
NaOH
Na2CO3
Ca(OH)2
CaCO3
CO2
H2O
Air
(O2, N2)
CH4CaCO3
H2O
O2
Source: Frank Zeman
CaO
Oxygen Depleted Air
(4)
Net Zero Carbon EconomyNet Zero Carbon Economy
CO2
extraction from air
Permanent & safe disposal
CO2 from concentrated
sources
electricity or hydrogen
Mineral carbonate disposal
Capture of distributed emissions
EnergySource
EnergyConsumer
H2O H2O
O2
O2
H2
CO2
CO2
H2 CH2
Materially Closed Energy Cycles
Sustainable on indefinite time scales
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