Coal and Petroleum
Science Class Eight
Types of Natural Resources
Natural Resources can be divided into two types in the light of their availability. These two types are Inexhaustible Natural Resources and Exhaustible Natural Resources
(a) Inexhaustible Natural Resources
Natural resources which are available in unlimited quantity and are not likely to be exhausted by human activities are called Inexhaustible Natural Resources. For example sunlight, air, etc.
(b) Exhaustible Natural Resources
Natural resources, available in limited quantity and can be exhausted by human activities, are called Exhaustible Natural Resources. For example forests, wildlife, minerals, coal, petroleum, natural gas, etc.
Fossil Fuels
Some natural resources, are used as fuel and formed from the dead remains of living organisms in millions of years after burying in earth and sea bed, are known as Fossil Fuels. For example coal, petroleum, natural gas, etc.
Since, fossil fuel takes millions of years to form and are limited in quantity, thus fossil fuels are called exhaustible natural resources.
Coal
Coal is a type of fossil fuel. Coal is hard as stone and black in colour.
Coal is one of the fuels used to cook food. Earlier, coal was used in railway engines to produce steam to run the engine. Coal is used in thermal power plants to run turbine which produces electricity. Coal is used in various industries also as fuel.
Story of Coal
Dense forest situated in low lying wetland areas of earth were buried under the soil due to many natural processes like flooding, earthquake, etc. about 300 million years ago. In the due course more soil deposited over them again and again and they were compressed because of heavy load of soils. As they went deeper and deeper more pressure and temperature act over them. Under such conditions of high temperature and pressure, those dead plants got slowly converted into coal.
As coal was formed from the remains of vegetation, coal is also called a fossil fuel.
Carbonisation
The slow process of conversion of dead vegetation into coal is called carbonization as coal contains mainly carbon.
Burning of Coal
On heating of coal in air, coal burns and produces carbon dioxide gas along with heat.
Process of coal into many other useful products
Coal is processed in industry to get many useful products such as coke, coal tar and coal gas.
Coke
Coke is made from the processing of coal. Coke is a tough, porous and black substance. Coake is almost pure form of carbon. Coke is used in the manufacturing of steel and in the extraction of many metals.
Coal Tar
Coal Tar is a product of coal. Coal Tar is a black and thick liquid. Coal Tar has an unpleasant smell.
Coal Tar is a mixture of about 200 substances. There are many products obtained from Coal Tar. Products obtained from coal tar are used as starting materials for manufacturing of various substances. For example synthetic dyes, drugs, explosives, perfumes, plastics, paints, photographic materials, roofing materials, naphthalene balls, etc.
Naphthalene balls obtained from coal tar is used to repel moths and other insects.
Coal Tar is used for metalling of the roads. These days, bitumin, a petroleum product, is used in place of coal tar for metalling the roads.
Coal Gas
During the processing of coal to get coke, Coal Gas is obtained. Coal gas is used in many industries especially situated near the coal processing plants.
Coal Gas and lightning of Street
Coal gas was used for street lightning for the first time in London in 1810 and in New York around 1820. Now a days, coal gas is used as source of heat rather than light.
Petroleum
Petroleum is a natural resource and found in nature in the form of raw fuel. Petroleum is mixture of many products like petroleum gas, petrol, diesel, lubricating oil, paraffin was, etc. This means that diesel and petrol are petroleum products.
Formation of Petroleum in Nature
Petroleum is formed from organisms living the sea. As these organisms died, their bodies settled at the bottom of sea. At sea bed with lapses of time; bodies of dead organism were keeping covered with many layers of sand and clay. Over millions of years, in the absence of air, in high temperature and high pressure the dead organisms were transformed into petroleum and natural gas.
Natural gas is lighter than petroleum and petroleum is lighter than water. Thus, natural gas, petroleum and water form separate layer. In those layers natural gas found in upper most layer, petroleum is found in middle layer float over the water.
Oil Reservoir
Areas, where petroleum is found but extraction of petroleum is not started are called oil reservoirs.
Oil Field
And areas from where petroleum is extracted are called oil fields.
Oil well
Point from where petroleum is extracted after drilling to make way to extract petroleum is called an Oil Well.
First Oil Well
The world's first oil well was drilled in Pennsylvania, USA, in 1859. Eight years later, in 1867, oil was struck at Makum in Assam.
In India, oil is found in Assam, Gujrat, Mumbai High and in the river basins of Godavari and Krishna.
Refining of Petroleum
Petroleum is mixture of many products like petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc. Thus products are to be separated from petroleum before their use.
The separation of various products of petroleum is known as Refining of Petroleum. And plant in which separation of different products from petroleum is carried out is called Petroleum Refinery.
Petrochemicals
Useful substances obtained from petroleum and natural gas, are known as Petrochemicals. Petrochemicals are used in manufacturing of detergents, artificial fibers, polythene, etc. Hydrogen gas obtained from natural gas is used in the production of fertilizers (urea).
Since, petroleum gives us many useful products, hence because of its great commercial importance, petroleum is often termed as Black Gold.
Natural Gas
Natural gas is obtained from its reservoir after drilled through pipes. Natural gas is very important fossil fuel. Natural gas can be transported through pipe lines easily.
Compressed Natural Gas
Natural gas compressed under high pressure is called Compressed Natural Gas and is abbreviated as 'CNG'.
Natural gas has great advantage as it can be used directly for burning in the homes and factories where it can be supplied through pipes and after compressed in cylinders. Such a network of natural gas pipe lines exists in Vadodra (Gujrat) and some parts of Delhi and other places.
Natural gas is burnt without creating much pollution, that's why Natural Gas is called clean fuel.
Natural gas is used as fuel in vehicles also. Natural gas is used as starting materials in the manufacturing of many chemicals and fertilizers.
In India, natural gas has been found in Tripura, Rajasthan, Maharastra and in the Krishna and Godavri delta.
Some Natural Resources are Limited
There are many natural resources are exhaustible and limited such as forest, fossil fuels, minerals etc. These exhaustible natural resources take millions of year to form. And the known reserves of these exhaustible natural resources will only last a few hundred years.
On the other hand burning of fossil fuels creates much pollution and their excess use is one of the major causes of global warming.
Thus these exhaustible fossil fuels should be used only while absolute necessary. The less use of fossil fuels is resulting in the better and cleaner environment, smaller risk of global warming and their availability for a longer period of time.
In India, the Petrochemical Conservation Research Association (PCRA) advises people how to save petrol/diesel while driving. Some of tips of PCRA are
(a) Vehicles should be driven at constant and moderate speed as far as possible.
(b) Engine of vehicles should be switched off at traffic signals or at a place where one has to wait.
(c) Correct tyre pressure should be ensured.
(d) Regular maintenance of the vehicle should be ensured.
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