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1. What fuels are often referred to as fossil fuels?
2. What types of fossil fuels do you know?
3. Is coke a natural or artificial solid fuel?
4. How are coke and charcoal produced?
5. What are the advantages of gaseous fuels?
The chief sources of energy available to man today are oil, natural gas, coal, water power and atomic energy. Coal, gas and oil represent energy that has been concentrated by the decay of organic materials (plants and animals) accumulated in the geologic past. These fuels are often referred to as fossil fuels.
Most fuels are carbon- containing substances that are burned in air. In burning fuels give off heat which is used for different purposes.
Fuels may be solid, liquid and gaseous. Solid fuels may be divided into two main groups, natural and manufactured. The former category includes coal, wood, peat and other plant products. The latter category includes coke and charcoal obtained by heating coal in the absence of air.
Coal is of great importance for the development of modern industry. It provides about 28 per cent of all the commercial energy used in the world. It may be used for domestic and industrial purposes. Being the main source of coke, coal is widely used in the iron and steel industry.
There is a strong tendency now for increased research into new technologies to utilize coal. No doubt, coal will be used as a raw material for the chemical industry and petrochemical processes. All these processes involve coal conversions which include gasification designed to produce
synthetic gas from coal as the basis for hydrogen manufacture, liquefaction for making liquid fuel from coal and other processes.
The mining, transportation and burning of coal involve serious problems. Strip mining destroys trees and produces some disturbances on the Earth’s surface which reduce its economic value. After coal has been mined, it is expensive to haul it from the mines. And when burned, it releases sculpture and other impurities that pollute the air and cause acid rains.
Liquid fuels are derived almost of petroleum. In general, natural petroleum, or crude oil, as it is widely known, is the basis of practically all industrial fuels. Petroleum is a mixture of hundreds of different hydrocarbons – compounds composed of hydrogen and carbon – together with the small amount of other elements such as sculpture, oxygen and nitrogen. Petroleum is one of the most efficient fuels and raw materials. It furnishes about 40 per cent of the commercial energy used in the world. It provides most of the energy applied for transportation and heats millions of homes as well.
Petroleum is easier to get out of the ground than coal, and pipelines carry it cheaply over long distances. Like coal, oil contains impurities that cause air pollution. But refineries can remove many of these pollutants when they process the petroleum.
Of gaseous fuels the most important are those derived from natural gas, chiefly methane or petroleum. Using gaseous fuels makes it possible to obtain high thermal efficiency, ease of distribution and control. Gas is the most economical and convenient type of fuels. It is the cleanest one and can easily be transported through pipelines, and it causes almost no pollution. Today gas is widely utilized in the home and as a raw material for producing synthetics. It accounts for about 20 per cent of the commercial energy used in the world.
Generally speaking, all types of fossil fuels described in the text are of great economic importance as they represent the sources of energy the man uses today.
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