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Coal and Electricity

Nathan Dooley and Cammie Lincoln
by

Cammie Lincoln

on 4 May 2010

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Transcript of Coal and Electricity

Coal has been an important factor in electrical production in the United States since the first power plants were built in the 1880's. History The earliest powerplants used hand-fed wood or coal to heat a boiler and produce steam...
...which turned generators to produce electricity
In 1884 a British engineer, Charles A. Parsons, developed a more efficient high speed steam turbine
Today coal power is based off of the same methods that started over 100 years ago. Coal and Electricity
By Nathan Dooley and Cammie Lincoln Timeline 1816- Baltimore becomes the first city to light streets with gas made from coal 1901- General Electric Co. builds the first alternating current power plant at Ehrenfeld, Pennsylvania, for Webster Coal and Coke Co., to eliminate inherent difficulties in long-distance direct-connect transmission. 1961- coal becomes a major fuel used by electricity utilities to generate electricity 1996- Energy Policy Act goes into effect, opening eletric utility markets for competition between fuel providers Current U.S. Energy Consumption The U.S. is the world's leader in electic power consumption with just under 4 TWh.

Thats about 20% of the world's electricity for less than 5% of the world's population! In the United States we consume 1.06 billion tons of coal a year. About 50% of the electricity generated in the U.S. comes from coal. Coal to Electricity Steam coal, or thermal coal, is used to generate electricity. Steps 1. Coal is milled to a fine powder 2. In puvarized coal combustion (PCC) systems, coal is blown into a combustion chamber of a boiler 3. Here the hot gases and heat energy produced convert water into steam 4. The steam pushes propeller-like blades in a turbine at high speeds. 5. The turbine provides mechanical energy to drive a generator. Electricity is produced when wire coils in the generator rapidly rotate in a strong magnetic field, creating a potential difference. 6. Steam is condensed and returned to the boiler to be heated once again 7. Electricity is transformed into higher voltages (up to 400,000 volts) used for econimic, efficient transmission through the power line grids 8. electricity nearing the point of consumption is transformed down to safer 100-250 voltage systems used in the domestic market Video The wide scale distribution of electric power was made possible by the development of the electric generator...which opperates off a principal formulated by English scientist Michael Faraday and American scientist Joseph Henry in 1831. The first public power station was built in London in 1882. Looking to the Future Whats Going On Now 2009 has had the largest new coal capacity additions in one year since 1991 Eight plants totaling 3,218 MW have become operational 2009 Capacity Additions
•Hugh L Spurlock (278 MW) - Eastern Kentucky
•Clinton (180 MW) - Iowa, Archar Daniels Midland Cogeneration
•Lamar (18 MW) - Texas
•Nebraska City Unit 2 (663 MW) - Nebraska
•Oak Grove (817 MW) - Texas
•Dallman(200 MW) - Springfield, Illinois
•Sandow5 (662 MW) - Texas
•Springerville(400 MW) - Arizona There has been a net decrease of 8,776 MW (-34%) of “Progressing” projects for the year The projects removed from the list are predominately due to today’s economic environment and regulatory uncertainty China has added nearly 220 GW capacity from 2004-2008 Over 70 GW in 2007 alone! There is no doubt that coal will maintain an intergral role in electricity production for the near future beacuse of its domestic abundance and relative low cost. PC Subcritical
Standard air-blown pulverized coal boiler
CFB
Standard Coal Fired Boiler
Typical Thermal Efficiency of these plant types
-30-37%- PC Supercritical

Pulverized coal boiler that uses water above the critical point ,705 °F (374 °C) and 3,212 psi (22.15 MPa), as the working fluid

Above the critical point, there is no phase transition from water to steam - no energy needed for vaporization

Typical Thermal Efficiency of Supercritical Plants
-40-45%-

New "ultra critical" designs using pressures of 4,400 psi (30 MPa) and dual stage reheat may reach about 48% efficiency
IGCC

Integrated Gasification Combined Cycle

Coal is first gasified to to produce syngas (CO + H2)

Syngas is cleaned and useful byproducts removed (solid sulfur)
1. Rectisol process uses chilled methanol to sperate CO2 and H2S
2. Claus process produces S(s) from H2S and seperates CO2

*This where IGCC is set-up for Carbon Capture

At this point syngas can be used to produce electricity or other fuels and chemicals
1. To produce electricity, syngas burned in gas turbine and then
waste steam used to drives steam turbine
2. To produce other fuels, syngas enter WGS reactor to obtain
desired H2 / CO ratio, then Fischer-Tropsh chemistry utilized
to produce desired fuel

Thermal Efficiency of IGCC plants may reach 60%!
Advantages
Virtually zero NOx and SOx emissions because of air seperation and sulfur recovery
Much higher efficiency
Production of alternate fuels at night when electricity demand is low

Disadvantages
Gasification operations are basically CO2 factories
Air seperation is very energy intensive because done at supercooled temperatures Environmental Impact
Comparison Study conducted by EPA's Gasification Technology Council on IGCC vs. PC (2006)

Basis
Plant size: 500MW
Plant configurations:
-Oxygen-blown IGCC, 1,800 psig / 1,000° F / 1,000° F
-Subcritical PC, 2,400 psig / 1,000° F / 1,000° F
-Supercritical PC, 3,500 psig / 1,000° F / 1,000° F
-Ultra-supercritical PC, 4,500 psig / 1,100° F / 1,100° F
(double reheat)
All PC plants have BACT environmental controls
The continuing goal is to develop new technologies to increase plant efficiencies and decrease emission and pollution rates. Many promising technologies exist but amizingly high capitol costs stand in the way. World Electricity Production Nearly 20 TWh of electrical energy are produced and consumed every year throughout the world. Over 10 TWh produced by coal alone! Powder River Basin Coal The Powder River Basin is a region in southeast Montana and northeast Wyoming, about 120 miles by 200 miles, or about 24,000 square miles and known for its coal deposits. The region supplies about 40 percent of coal in the United States. In 2007, the Powder River Basin alone produced 436 million short tons of coal, more than twice that of West Virginia.

Powder River Basin coal is classified as "sub-bituminous" and has a average heating value of 8,500 btu/lb.

Powder River Basin coal is used so extensivley in the U.S. because of its with low sulfur concentration. Closing Remarks Coal is, and will continue to be a vital fuel for our countries electricity production because of its domestic abundace and relative cheap cost. Government decisions on carbon emission and GHG regulations will ultimatly guide the future of power plant technologies. Sources “American Energy Stats.” 2003-2010. Nation Master. 17 Apr. 2010<http://www.nationmaster.com/country/us-united-states/ene-energy>
“Coal & Electricity.” World Coal Institute. 2010. World Coal Institute. 17 Apr. <2010http://www.worldcoal.org/coal/uses-of-coal/coal-electricity/>
Coal Fired Power Generation.” 17 Apr. 2010http://www.rst2.edu/ties/acidrain/IEcoal/how.htm#References:
"electric power." Encyclopædia Britannica. 2010. Encyclopædia Britannica Online. 17 Apr. 2010 <http://www.britannica.com/EBchecked/topic/182711/electric-power>.
“Timeline of Coal in the United States.” American Coal Foundation. 2005. American Coal Foundation. 17 Apr. 2010http://www.teachcoal.org/lessonplans/pdf/coal_timeline.pdf


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