Origin of coal b.sc.sem. v paper i final

Origin of coal

1. Origin of coal Dr. C. P. Dorlikar Department of Geology

2. Content - Introduction Chemical composition Origin Type Uses

3. The Gondwana coals are largely confined to the river valleys like the damoder , Mahanadi , Godavari etc. The workable coal seams are confined lower gondwana .

4. Introduction - Coa l - Coal may be defined as a solid stratified rock composed mainly of carbonized plants. Coal is the worlds leading mineral fuel. It is burned to produce heat which is used to generate electric power. On heating in air free atmosphere such a coal converted to coke .

5. Chemical composition - Coal is composed chiefly of carbon , oxygen ,hydrogen , nitrogen , traces of sulfur and phosphorous . Carbon being the major component . The chemical composition of coal may be in the following range. Carbon (60-90 % ) Oxygen (2-20%) Hydrogen (1-12 % ) Nitrogen (1 – 3%)

6. Origin of coal- Coal are sedimentary rocks formed by accumulation of plant materials in swamps , Hence the source material of coal is the vegetation matter . The formation of a coal deposit require a large accumulation of vegetation matter. There are two theories to explain the mode of accumulation of plant materials to give rise to coal seam. The in situ theory Drift theory

7. Type of coal - Coal is divided into four major classes –

8. Peat - Peat is not considered as coal though it is a fuel . It represent the first stage of coal formation. Peat is a brown porous mass of partly decomposed vegetable material. Chemically it is very rich in moisture and consist of carbon , hydrogen , sulfur and nitrogen as important constituent.

9. Type of peat- There are two type of peat - Bog peat – Which is evolved out of lower type of vegetation like masses . 2 ) Mountain peat- That is decomposed and partially altered form of higher type of trees. It is found in sub- mountainous regions .

10. Lignite - Lignite is also called brown coal as its colour is often dark brown. It represent the second stage of in coal formation . The lignite is composed of finely divided plant tissue. The lignite burns freely with along smoky flame . Lignite has a low calorific value(1100- 12500B.T.U )

11. The composition of Lignite – Fixed carbon-50% Oxygen-20-25% Hydrogen -5% Nitrogen-2-5% Sulfur – 1-2%

12. Bituminous coal – It is also known as common coal . It is a dense coal of black colour . Bituminous coal has compact structure breaking almost cubical fragment. It burn with a yellow flame. Its calorific value ranges between 13500 to 16000 B.T.U.

13. Bituminous coal is distinguished into 3 types - On the basis of carbon content – Sub- bituminous Bituminous Semi-bituminous

14. In composition- carbon – 92-97% hydrogen – 1-3% O+N - 1-3% Anthracite-

15. Anthracite- It is a coal of highest rank in which original organic source has been completely transformed into carbonaceous substance. Anthracite is a hard coal with an iron –black colour and sub-metallic lustre . It is burns with short blue flame . Calorific value – 15000 to 15600 B.T.U.

16. USES - Coal is a primary source of heat and power ( thermal power ) It is also used in the production of water gas. In metallurgical oporations , for the purpose of oxtractions of metals like iron, zinc etc.