Fossil Fuels: Burning to get Electricity

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Fossil Fuels Burning to get Electricity
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We use this energy

• Direct vs. Indirect Solar Energy
• Heat, biomass, wind, hydro
• Commercial Energy
• Must be extracted burned

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It takes energy to get energy!

• Find
• Pump
• Transfer
• Convert
• Transport
• Burn

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Coal
Gas
Oil
High potential areas
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PetroleumOil, Black Gold, Texas Tea

• Buried sunshine
• Polymer of combustible hydrocarbons
• Rich in energy when burned
• Can be transformed to produce a wide variety of
  materials

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How do we get it?

• Primary oil recovery
• drilling a well
• pump out lighter crude oil
• Secondary oil recovery
• pumping high pressure water into a well to force
  oil through rock pores
• pumping oil to surface
• separating heavy oil
• reuse water to recover more oil
• Tertiary oil recovery
• get remaining heavy oil by pumping CO2 or
  injecting detergent

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More on Oil Drilling
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Petroleum Its only useful when its distilled

• Fractional distillation - using boiling points to
  separate crude oil into useful components
• Crude oil is heated in a furnace
• Then pumped into the the base of a fractioning
  tower
• Fractions are collected

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Gases
Gasoline
Aviation fuel
Heating oil
Diesel oil
Naphtha
Grease and wax
Furnace
Fig. 14.16, p. 337
Asphalt
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Petroleum Not just for electricity

• Plastics - flexible and rigid
• Fabrics
• Pharmaceuticals - aspirin, antiseptics
• Alcohols - solvents, flavors, cosmetics
• Sweeteners
• Perfumes
• Dyes
• Explosives
• Asphalt

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Who Has the Oil?

• 11 countries in OPEC have 67
• 64 are in the Middle East
• Saudi Arabia has 26
• Remaining 36 in Latin America, Africa, former
  Soviet Union, Asia, Europe and U.S.
• U.S. has 2.3

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Will the Oil Last?

• Use has grown exponentially
• Production will peak between 2010 and 2030
• U.S production peaked in 1975
• Known and projected supplies will be depleted
  within 42-93 years
• U.S. will be depleted within 15-48 years

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Disadvantages
Advantages
Ample supply for 4293 years
Need to find substitute within 50 years
Low cost (with huge subsidies)
Artificially low price encourages waste and
discourages search for alternatives
High net energy yield
Easily transported within and between countries
Air pollution when burned
Low land use
Releases CO2 when burned
Petroleum
Moderate water pollution
Fig. 14.21, p. 340
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Tar sand is heated until bitumen floats to the
top.
Bitumen vapor Is cooled and condensed.
Tar sand is mined.
Pipeline
Hydrogen added
Impurities removed
Synthetic crude oil
Refinery

• Clay, sand, water combustible bitumen
• Most deposits are too deep to be mined
• Some surface mining
• Bitumen can be purified into synthetic crude oil

Fig. 14.24, p. 341
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Oil Shale

• Fine-grained sedimentary rock containing
  combustible kerogen
• Can be distilled to form shale oil
• Takes too much energy to mine and convert kerogen
  to crude oil

Fig. 14.22, p. 340
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Advantages
Disadvantages
Moderate existing supplies
High costs
Low net energy yield
Large potential supplies
Large amount of water needed to process
Oil Shale Tar Sand
Severe land disruption from surface mining
Water pollution from mining residues
Air pollution when burned
CO2 emissions when burned
Fig. 14.25, p. 342
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Natural GasUh, no, not from you!

• Mixture of methane and smaller amounts of ethane,
  propane, butane and hydrogen sulfide
• Conventionally lies above most crude oil
  reservoirs
• Methane hydrate - bubbles of gas trapped in ice
  crystals or in ocean sediments
• Click here for a great site its a gas!

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Liquefied Gas

• Propane and butane gases are liquefied and
  removed as LPG
• Leftover gas, methane is
• dried
• cleansed of hydrogen sulfide
• pumped and pressurized for distribution
• LNG can be shipped

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Click here for Nicor Gas
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Click to check out how gas is processed
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Where is this gas?

• Russia and Kazakhstan have 42
• U.S. has 3
• Most U.S. gas reserves are located in same places
  as crude oil.

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Future of Gas?

• Global supplies of conventional and
  unconventional gas should last 205-325 years.
• Combined-cycle natural gas systems
• produce more electricity cheaper
• less CO2 and Nox
• 200 plants by 2015

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Advantages
Disadvantages
Ample supplies (125 years)
Releases CO2 when burned
High net energy yield
Methane (a greenhouse gas) can leak from
pipelines
Low cost (with huge subsidies)
Shipped across ocean as highly explosive LNG
Less air pollution than other fossil fuels
Sometimes burned off and wasted at
wells because of low price
Lower CO2 emissions than other fossil fuels
Moderate environ- mental impact
Conventional Natural Gas
Easily transported by pipeline
Low land use
Good fuel for fuel cells and gas turbines
Fig. 14.26, p. 342
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Coalnot just for bad kids

• Solid fossil fuel that is mostly combustible
  carbon
• Coal formed in several stages
• buried plant remains in swamps subjected to heat
  and pressure
• Anthracite is 98 C
• Extracted underground
• Area Strip mining - flat terrain
• Contour strip mining - hilly terrain
• Transported, broken, crushed, and cleaned

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Increasing heat and carbon content
Increasing moisture content
Peat (not a coal)
Lignite (brown coal)
Bituminous Coal (soft coal)
Anthracite (hard coal)
Heat
Heat
Heat
Pressure
Pressure
Pressure
Partially decayed plant matter in swamps and
bogs low heat content
Low heat content low sulfur content limited
supplies in most areas
Extensively used as a fuel because of its high
heat content and large supplies normally has
a high sulfur content
Highly desirable fuel because of its high heat
content and low sulfur content supplies are
limited in most areas
Coal Formation
Age increases Carbon content
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How is coal used?

• 22 of worlds commercial energy.
• 62 or worlds electricity
• 75 of worlds steel
• 52 of U.S. electricity
• 20 nuclear
• 14 natural gas
• 10 renewable
• 2 oil
• Background Picture is Anthracite

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Advantages
Disadvantages
Ample supplies (225900 years)
Very high environmental impact
Severe land disturbance, air pollution,
and water pollution
High net energy yield
Low cost (with huge subsidies)
High land use (including mining)
Severe threat to human health
Coal for energy
High CO2 emissions when burned
Releases radioactive particles and mercury
into air
Fig. 14.28, p. 344
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Future of Coal?

• With identified and unidentified reserves, 965 -
  1125 years
• Highest environmental impact
• land disturbance
• air pollution
• CO2 emissions
• mercury and radioactive particles
• Synthetic Natural Gas by coal gasification
• Liquid fuel such as synthetic gas by coal
  liquefaction

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Flue gases
Coal
Limestone
Steam
Fluidized bed coal combustion
Removes sulfur Reduces NOx Efficient burning
Fluidized bed
Water
Air nozzles
Air
Calcium sulfate and ash
Fig. 14.29, p. 345
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Raw coal
Recover sulfur
Air or oxygen
Raw gases
Clean Methane gas
Steam
2C Coal

O2
2CO
Pulverizer
Recycle unreacted carbon (char)
CO

3H2
CH4

H2O
Methane (natural gas)
Slag removal
Pulverized coal
Coal Gasification for converting solid coal into
methane
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Advantages
Disadvantages
Large potential supply
Low to moderate net energy yield
Higher cost than coal
Vehicle fuel
High environmental impact
Increased surface mining of coal
High water use
Higher CO2 emissions than coal
Synthetic Natural Gas
Fig. 14.31, p. 346
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Spent fuel assemblies
Fuel assemblies
Reactor
(conversion of enriched UF6 to UO2 and
fabrication of fuel assemblies)
Open fuel cycle today
Prospective closed end fuel cycle
Fuel fabrication
Interim storage Under water
Enriched UF6
Plutonium-239 as PuO2
Enrichment UF6
Spent fuel reprocessing
Uranium-235 as UF6
High-level radioactive waste or spent
fuel assemblies
Uranium tailings (low level but long half-life)
Conversion of U3O8 to UF6
Processed uranium ore
Geologic disposal of moderate- and
high-level radioactive wastes
Uranium mines and mills Ore and ore concentrate
(U3O8)
Fig. 14.33, p. 347
Front end
Back end
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