| E n e r g y : Fuels Part II | |
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COAL Coal is just as useful at charcoal. There are a few types of coal that provide energy. Lignite, peat, anthracite, and bituminous are some forms that were created due to the incompletion of the carbonization process. Different coals are given different "grades" depending on the amount of sulfur. Coal is broken up into different components such as coal gas, coal tar, and coke. Coal tar is made of carbon compounds. Coal gas is made of hydrogen, methane, and carbon monoxide gasses which all have high calorific value. Coke is made of carbon only. Coke is also useful to make water gas, CO + H2, and producer gas, CO + N2. The high calorific value of coal allows it to burn easily and be good fuel. The combustion of coal, hydrocarbons are converted into CO2 and H2O. The sulfur in the coal goes through this reaction: 2S(s) + O2(g) --> SO2(g). Sulfur dioxide is prodced as a by-product of coal combustion in coal-fired power plants. The products CO2, CO, and H2O, SO2 gases are then blown out the stack of the plant (Notes in Brief).
Though coal is a useful form of fuel due to its high heating value, it has certain impurities that limit its success. Sulfur and various other minerals combine with the oxygen to form sulfur dioxide, a poisonous gas, sulfuric acid, SO2 + H2 --> H2SO3. Ash is formed. Low-sulfur coal can be burned in large quantitites without adding harmful amounts of sulfur dioxide but medium and high-sulfur colas cause air pollution if there are improper safeguards. |
Figure 4
The ash formed can become "fly ash" because some ash may escape into the air that also causes air pollution. The bituminous coals are the most plentiful having the highest heating value but are difficult to handle and transport due to its dryness and dustiness.
Coal, being natural, is formed over millions of years in decomposition of plants. Coal is beneath the deep earth due to phenomena like earthquakes and volcanoes. Slow conversions include wood through bacteria, high temperature, and high pressure that slowly convert it to coal. This is known as carbonization. Coke is made by heating bituminous coal to about 2000 degrees Fahrenheit in an airtight oven. The lack of oxygen prevents the coal from burning. Some of the coal will be changed into gases due to the intense heat. Some turn into liquid ammonia, coal tar, or light oil as they cool down. Most of coke is produced to make iron and steel. Vertical shafts made of steel and concrete would useful to make a coal mine. These shafts would reach down the deep earth to reach the ore containing the coal. Steel would come from the Arda Metal Group. Coal formation naturally started through the collection of decayed vegetable matter. Compaction and heating while underground converts it to black coal. This would be the most ideal method for Planet Arda. |
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