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COAL IS GOOOOOD!!!!!
GOOD
GOOD
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GOOD
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GOODCOAL
COAL
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COAL
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COAL
COAL
COAL
GOOD
COAL IS GOOOOOD!!!!!
Coal was discovered in eastern north America in the 18th century. We needed to fuel steam engines, and coal was a readily available fuel. Fuel was burned to create steam to turn a turbine. Today 50% of U.S. electricity comes from coal. We have 300 years’ worth of coal!
COAL IS GOOOOOD!!!!!
Underground MiningRoom and Pillar Mining – rooms are cut into the coal bed leaving a series of pillars or columns of coal to help support the mine roof and control the flow of air. The miners advance while cutting out pillars. Once they reach the edge of the mine, they work backwards in what’s called “retreat mining.”
Long Wall Mining – hydraulic roof supports are used while a cutting head goes back and forth along the coal face. When the cutting head reaches one end of the coal face, it dumps the coal onto a conveyor belt.
Surface Coal MiningSurface mining occurs at exposed coal seams. It involves drilling above ground and blasting to remove overburden. After the overburden is removed, the mined coal is harvested.
Coal is pretty cheap. In 2004, the average price for a short ton of coal in the U.S. was $19.93 (although this does represent an increase from the 2003 price of $17.85).
It is estimated that there 265 billion short tons of coal available in the United States to be mined.
Mmmmmm, Coal. D’oh!
Energy in coal:Lignite – 13 million Btu per tonSubbituminous – 18 million Btu per tonBituminous – 24 million Btu per tonAnthricite – 23 million Btu per ton
But… Coal is DIRTY!!!!!!
There are several negative externalities attributed to the combustion of coal, including:- sulfer and acid rain,- carbon Dioxide, and- general destruction to the environment due to the actual coal mining.
A 500 megawatt coal power plant will produce 10,000 tons of Sulfur dioxide, 10,200 tons of nitrogen dioxide and 3.7 million
Tons of carbon dioxide per year.
OVERBURDENWhen mining, “overburden” is left over. Mining one ton of coal leaves 25 tons of overburden. Pyrite is contained in overburden; when pyrite is exposed to water and air, it forms dangerous substances like sulfuric acid and iron hydroxide. When this mixes with water, it forms acid lime drainage which is highly destructive to the environment. So sad .
COAL IS GOOOOOD!!!!!
Coal gasification reduces greenhouse gas emissions (really low sulfur oxide and nitrogen oxide emission).
Coal gasification is much more efficient than normal coal burningEfficiencies tableCurrent normal: 30%Current gasification: 50%Future gasification: 70-80%
The UK is developing underground coal gasification (UCG)!
This is a very clean method, as only gas is removed from the ground, leaving all the overburden and ash underground.
One must also remember that gasified coal is not only very clean, but is a far more versatile fuel than regular coal. Think about it: would you rather fuel your car with lumps of coal or gasified coal?
COAL IS GOOOOOD!!!!!
Here are two of several ways: Direct, and Indirect
Direct liquefaction – involves the introduction of hydrogen gas and catalysts into finely crushed coal to produce synthetic crude oil. Need temperatures of 430-450*C and pressures of 50 to 25 MPA. Hydrogen is needed to remove the oxygen sulfur and nitrogen. The product of direct liquefaction must still be refined to gasoline or diesel.
Indirect liquefaction – first converted to gas through gasification. Then methanol synthesis is used to convert the coal gas into methanol, then the methanol can either be directly converted to gasoline, or it can be used as fuel in and of itself.
COAL IS GOOOOOD!!!!!
Deep oceanMines
Plants (aquatic and land)
COAL IS GOOOOOD!!!!!
Fly ash
Coal coke
Advanced Combustion
Captured by electrostatic precipitators.Used to replace 10%-30% of Portland cement.Can also be used as “flowable fill” to build highways.Unfortunately, current rates of recycling fly ash is only 35%.
Advanced Combustion
Cole coke is created from bituminous coal (very dirty!!). The bituminous coal is put in to an airless “coke oven” where it is heated to over 1,000*C. This removes much of its volatile content such as water, tar, and sulfur. Can be used for things that require “clean coal.”
