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Clean Coal Technology

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Title: Clean Coal Technology


1
Clean Coal Technology
  • Sam Harris

http//i.treehugger.com/images/2007/5/24/coal20ch
unks.jpg
2
Overview
  • Burning and current use of Coal
  • Clean coal technologies
  • Is clean coal actually clean?
  • The future of clean coal and politics
  • Summary

3
Types of Coal
  • Lignite (brown coal) - 25 to 35 carbon, around
    70 when dry
  • Subbituminous 35 to 45 carbon
  • Bituminous 45 to 86 carbon
  • Anthracite (black coal) 86 to 98 carbon

4
Coal and Electricity
  • There are about 600 U.S. coal plants.
  • Coal generates 54 of our electricity
  • There are 249 projected coal power plants to be
    built between 1999 and 2009, another 483 by 2019,
    and another 710 by 2030

5
Burning of Coal
  • In 2002 fossil fuels released 23 billion tons of
    CO2 into the atmosphere
  • of the 23 billion tons 41 was from coal
  • Burn 1 ton of black coal and you get 4 tons of
    CO2
  • Anthracite releases 67 more CO2 than methane and
    brown coal releases 130 more CO2 emissions than
    methane
  • Coal also contains trace amounts of sulfur and
    Nitrogen that when burned can cause environmental
    issues

6
The Effects of Sulfur Dioxide from Coal
  • In the 1960s trees as well as aquatic life in
    lakes were dying
  • Due to acid rain from sulfur dioxide emissions
    from burning of coal
  • Created scrubbers to clean the coal
  • The sulphates had reflected light back into space
    keeping the earth cooler
  • Once the sulphates were gone the temperature of
    the earth rose

7
Why is coal still used?
  • Cheapest for power stations relative to the
    amount of heat it generates when burnt

http//www.economist.com/business/displaystory.cfm
?story_id10145492
8
How does a coal power plant work?
http//www.cs.wright.edu/egr190/Alternative20ene
rgy/coalart.gif
9
http//upload.wikimedia.org/wikipedia/commons/d/d6
/Coal_power_plant_Datteln_2_Crop1.png
10
So what is clean coal?
  • It is actually a vague term that does not
    describe any one process
  • Can include the removal of nitrogen and sulfur
    that create acid rain
  • Can include the storage of CO2
  • The term clean coal is abused

11
Clean Coal Technologies
  • Coal washing
  • Wet scrubbers
  • Low NOx burners
  • Electrostatic precipitators
  • Gasification
  • Carbon Capture and Storage (CCS)
  • Fuel Cells
  • Magnetohydrodynamics

12
Coal Washing
  • Grinding coal into pieces and passing it through
    gravity filtration
  • One technique Putting coal into a barrel with a
    liquid with a specific density where the coal
    floats and the impurities sink

http//news.bbc.co.uk/1/hi/sci/tech/4468076.stm
13
Wet Scrubbers
  • When the emissions reach the flue of the furnace
    limestone and water are sprayed
  • The SO2 reacts with the calcium carbonate
    (limestone) to form gypsum (calcium sulfate)
  • The gypsum is collected and used for construction
  • 99 effective

http//news.bbc.co.uk/1/hi/sci/tech/4468076.stm
14
Nitrogen Oxides (NOx)
  • Use of
  • First stage combustion occurs in an oxygen
    deficient zone where NOx is usually formed
  • Second Stage hydrocarbons are formed which react
    with the already formed NOx
  • Third Stage - internal air staging completes the
    combustion but may result in additional NOx
    formation, which can be minimized by completing
    the combustion in an air lean environment

15
Electrostatic Precipitators (Particle emissions)
  • Creates an electrical field that removes unwanted
    charged particles
  • 99 effective

http//news.bbc.co.uk/1/hi/sci/tech/4468076.stm
16
Gasification
  • Coal is reacted with oxygen and steam to form a
    syngas (mostly hydrogen and part CO)
  • Syngas is cleaned and burned which then turns a
    turbine
  • As gas cools it heats water, which turns another
    turbine

17
http//news.bbc.co.uk/1/hi/sci/tech/4468076.stm
18
Gasification (continued)
  • Gasification is seen as part of zero-emission
    system
  • Improved SO2 and NOx emissions (already low)
  • Unproven on widespread scale
  • Up to 45 efficient
  • Currently only demonstration units exist on a
    trial basis
  • Right now syngas being cleaned at low
    temperatures. In the future will be cleaned at
    higher temperatures, increasing efficiency
  • Costly, but current coal power plants can be
    modified

19
Carbon Capture and Storage (CCS)
  • Capturing CO2 and storing it underground
    (geosequestration)

http//news.bbc.co.uk/1/hi/sci/tech/4468076.stm
20
CSS (continued)
  • There are many problems with CSS
  • CO2 is hard to capture
  • Once captured it needs to liquified which takes
    20 of the energy yielded from the coal
  • Where the CO2 is stored needs to be monitored
  • There are only so many places that are good for
    mass storage
  • Transportation could be costly

21
Fuel Cells
  • Allow hydrogen from coal to react with oxygen to
    produce electricity electrochemically
  • Still in early development
  • Costly

http//www.australiancoal.com.au/cleantech.htmfue
lcell
22
Magnetohydrodynamics
  • Coal is burned to form an extremely hot gas or
    plasma
  • Given electrical charge by adding a compound like
    potassium salt
  • The charged gas or plasma is passed through a
    magnetic field and electricity is produced
  • The heat from the combustion gases is used to
    turn a steam turbine too
  • Still in development
  • Costly

23
So is clean coal really clean?
  • Unfortunately there is no way to make coal clean
  • Processes like gasification can make coal burning
    more efficient, but it still burns plenty of CO2
  • CO2 can be stored underground using CSS, but that
    could lead to more problems in the future
  • Best solution STOP USING COAL!!!!

24
Clean Coal and Politics
  • Barack Obama has said that he would develop five
    first-of-their-kind coal-fired plants with CCS
    technology
  • Wants to spend 150 billion over 10 years for
    renewable energy sources such as wind, solar,
    biofuels, plug-in hybrids and clean-coal
    technology
  • Wants to cut carbon-dioxide emissions from power
    plants, oil companies and other industries.
  • But we're talking politics.

25
Summary
  • Coal is very inefficient and is a huge cause of
    global warming, but cheap
  • Clean coal is a term that describes many
    different technologies
  • Clean coal is by no means clean
  • CSS will be put in use in the near future, which
    may or may not be a good thing

26
Works Cited
  • "Clean Coal Technologies - Examples." Australian
    Coal Association. Australian
  • Clean coal technology How it works." BBC News.
    28 Nov. 2005. BBC News. 6
  • "Coal power Still going strong." The Economist 15
    Nov. 2007.
  • Davidson, Paul. "Major issues await Obama." USA
    Today 6 Nov. 2008.
  • Flannery T. 2005. The Weather Makers How Man is
    Changing the Climate and
  • "IEA Clean Coal Centre." IEA Clean Coal Centre.
    IEA Clean Coal Centre. 6 Nov.
  • Schirber, Michael. "What Exactly Is Clean Coal?"
    Foxnews.com. 3 Nov. 2008. Fox
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