Wednesday, October 30, 2013

Non-renewable energy sources

NON-RENEWABLE ENERGY SOURCES
  1. Coal: Coal is a solid fossil fuel formed in several stages as burried remains of land plants that lived 300-400 million years ago and were subjected to intense heat and pressure over millions of years.
Various stages of coal: The various stages of coal during formation of coal from wood are:
                                      i.  Wood
                                      ii  Peat
                                      iii  Lignite
                                      iv  Bituminous coal and
                                      v  Anthracite
Carbon content of anthracite is 90% and its calorific value is 8700 kcal. Carbon content of Bituminous coal, Lignite and Peat are 80%, 70% & 60% respectively. India has approximately 5% of the worlds coal. However, it is not of good quality as it has poor heat capacity.

Disadvantages of using coal:
  1. Burning coal produces carbondioxide which is the main cause for global warming
  2. Coal contains impurities like Sulphur and Nitrogen which produce toxic gases when burnt.
  2.  Petroleum: Petroleum or crude oil is a thick liquid consisting of more than 100 cumbustible hydrocarbons with small amounts of S, O and N as impurities. Fossil fuels are mainly sormed by the decomposition of dead plants and animals that were buried under lakes and oceans  at a high temperature and pressure for millions of years. From the crude petroleum oil, various hydrocarbons are separated by fractional distillation of crude petroleum oil. At the present rate of usage, the world's crude oil reserves are expected to get over in the next 30 years.

LIQUIFIED PETROLEUM GAS (LPG)
The petroleum gas obtained during crackling and fractional distillation can be easily converted into liquid under high pressure as LPG. LPG is a colourless, odourless gas to which mercaptans are added to produce foul smell that aids in detection of LPG leaks.

NATURAL GAS Natural gas is found above the oil in oil well. It is a mixture of 50-90% methane and small amounts of other hydrocarbons. Its calorific value ranges between 12000 and 14000 kcal/m3.
     1. Dry gas: Natural gas containing low hydrocarbons like d ethane, it is called dry gas.
     2. Wet gas: Natural gas containing high hydrocarbons like propane and butane along with methane is called wet gas.
Natural gas is formed by decomposition of dead plants and animals buried under oceans at high temperature and pressure for millions of years.

NUCLEAR ENERGY:
Dr. Homi Bhabha was the father of nuclear power development in India. India has 10 nuclear reactors that produce 2% of India's electricity. Nuclear energy is produced by two types of reactions:

(i) Nuclear fission: Nuclear fission is a nuclear chain reaction in which the heavy nucleas is split into lighter nuclii by fast moving neutrons thereby releasing a large amount of energy.
Ex: Fission of Uranium235

(ii) Nuclear fusion: Nuclear fusion is a nuclear chain reaction in which lighter nucleus are combined together at extremely high temperatures to form heavy nucleus thereby releasing large amount of energy.
Ex: Fusion of Dueterium atoms to form helium with release of large amount of energy.

Nuclear power plants have been established in the following locations in India:
i.     Tarapur (Maharashtra)
ii     Rana Pratap Sagar (Rajasthan)
iii    Kalpakkam (Tamil Nadu)
iv    Narora (Uttar Pradesh)

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