Sustainable Fossil Fuels?

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



sources


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



sources


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



sources


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)


CO2

extraction from air



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

Sustainable Fossil Fuels?

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