Types of coal

Classification of coal :- 

It is classified different categories according to various different criteria which is as follows as 

1. on the basis of ingredients of plants or different portion of plants

which is subdivided into four parts 

a. banded coal :- 

This type of coal is generally formed by peat swap which is formed as a result of decaying vegetable matter.

b. splint coal :- 

generally this type of coal has dull lustre and it seems greyish black colour and have a compat structure while burning this type of coal it burns freely and doesn’t swell on burning

c. channel coal :-

 this type of coal has dark black or greenish in colour and has a uniform compact structure these have a grained texture also it hasn’t any banded structure

d. bog head coal :- 

This type of coal has many similar properties like channel coal; the behaviour of this coal is similar to channel coal during burning and these contain high amounts of algal remains as well as volatile matter. also these coal gives high yield of tar and oil on distillation of these coals 

2. on the basis of rank :- 

As we see above , coal is divided into different sub categories on the basis of their properties and by their behaviour. so hear in this categories the coal is divided into their various subcategories by their rank which is nothing but subdivided according to their degree of metamorphism or progressive transformation in the natural series from wood to anthracites which results in the decreasing order of various ingredients such as moisture content, hydrogen content, nitrogen, sulphur and the amount of volatile matter in the coal.

so let’s begin with the very first classification which is as follows 

1. peat :- 

peat is the first stage of coal formation which is formed by vegetable matter is neither seems like old nor like as coal 

peat is fibrous compact compound which is either brown or black in colour and contains large quantities of water and inorganic compounds while it is burnt in dyr position it burns slowly also it has very less calorific value due to the presence of moisture and volatile content in this solid fuel.

its calorific value lies between 6000 to 9000 BTU per lb.(5400 kcal/kg).usually it is used as a domestic fuel 

2. lignite :- 

This type of coal comes after the lignite and it is the second stage of formation of coal from wood. It has the composition intermediate between peat and bituminous coal usually it is present in the brown colour. it may have amorphous fibrous or woody texture but also this type of coal contains high amount of moisture with it 

3. bituminous coal :- 

so it is the third stage of coal this type of coal is formed by the decomposition of vegetable matter besides it is a compact type of material and widely used as a mineral coal 

the type of coal bun with yellow and luminous flame and also exhibits a laminated structure allowing it to contain 80 to 90% of carbon in it. it is further subdivided into four parts which is as follows :- 

a) sub bituminous :-

 This type of coal contains a high amount of volatile matter and has a black, smooth and homogeneous nature. The amount of carbon in  this type of coal lies between 75-83% and the calorific value of this type of coal is between 7000-7500 kcal/kg.

b) semi bituminous coal :- 

This type of coal contains very less amount of volatile matter in it. Also the carbon content in this coal lies between 90-95% often this type of coal is used for manufacturing coke. it’s calorific value lies between 8350-8500 kcal/kg 

c) bituminous coal :-

 this type of coal carbon content around 78-90% and amount of volatile matter is around 25-45% these exhibits banded type of coal and the calorific value of his type of coal is around 8000-8500 kcal/kg 

d) super bituminous coal :- 

amoun all the types of bituminous coal it is the highest grade of coal with its high carbon content and less volatile matter in it. it’s calorific value lies between 8500-8650 kcl/kg. It burns without smoke and has the highest heating power among the other bituminous coal. 

4. Anthracite coal (high rank coal ) :- 

It is the final stage of formation of coal. It is hard, compact, black colored coal with a good semi metallic lustre also it has a high amount of fixed carbon in it and least amount of volatile matter is present in this type of coal this contamination makes this coal much more powerful than any other coal. ash content in this coal is around 2-3%. 

It is a very expensive coal in all the categories. It is used in industries for the metallurgy process also it burns slowly that’s why it is used as a domestic fuel. 

their calorific value lies between 8650-8700 kcl/kg 

In India it is found in himalayan hills of kashmir and lower gondwana starta in darjeeling.

 

I hope the above mentioned information helps for understanding about the coals and it's types 

Thankyou and have a amazing day 

BY :- ADARSH GUPTA