Introduction to Coal

Imagine a barbecue party without the coal or a bonfire without coal. It

doesn’t sound well, right? Coal is an important fuel that helps us to

cook, produce electricity, produce steel, etc. What is the science

behind coal? How is it obtained? What are the uses of coal? Let us

find out more about it.

Introduction to Coal

The word “coal” is taken from Old English word “col” which means

glowing ember. Coal is a black sedimentary rock. It usually occurs in

coal beds found in coal mines. Coal comprises of carbon, hydrogen,

oxygen, sulphur, etc. When dead plants and animals decay and convert

into peat which in turn is converted into lignite, then sub-bituminous

coal, after that bituminous coal, and lastly anthracite. Hence, coal is a

fossil fuel. It takes places due to geological process and takes millions

of years to form. Coal is extracted by mining. China is the world’s top

coal producer.

Formation of Coal

It takes millions of years for coal to form. Millions of years ago, there

were places on the earth with dense forests in wetlands, due to natural

calamities such as flooding, tsunami, landslide, etc these forests got

buried under the soil. Over the years, more and more soil compiled

over these forests. Oxidation protected these trees from

biodegradation, usually by mud or acidic water. This traps the carbon

that was buried in the sediments. Carbonization takes place,

carbonization is a process where vegetation turns into carbon. It is a

slow process.

Learn more about Coal Tar and Coal Gas here.

Uses of coal

Coal has various purposes, the following are the uses of coal :

● Thermal coal is used to produce electricity.

● Coking coal is used in the production of steel.

● Coal is also used to make silicon metal which is used to

produce silicones and silanes, which are in turn used to make

lubricants, water repellents, resins, cosmetics, hair shampoos,

and toothpaste.

● Activated charcoal is used to make face packs and cosmetics.

● Carbon fibre is made from coal. Carbon fibre is an extremely

strong but lightweight reinforcement material used in

construction, mountain bikes, and tennis rackets.

● Activated carbon is used in filters for water and air purification

and in kidney dialysis machines. Coal is used to make activated

carbon.

● Paper manufacturers use coal to make paper.

● Coal helps to create alumina refineries.

● Thousands of different products have coal or coal by-products

as components: soap, aspirins, solvents, dyes, plastics, and

fibres, such as rayon and nylon.

Solved Examples For You

Q1. What is carbonization?

a. The process of decomposition of animals and plants

b. It is the process of burning coal

c. The process of extracting coal

d. It is the process of conversion of vegetation into carbon

Sol: Carbonization is a process where the vegetation turns into carbon.

Q2. How is coal procured?

a. Mining

b. Decomposing

c. Condensing

d. Cloning

Sol: Coal is found in coal beds or coal seams. These coal beds or coal

seams are found in coal mines. Coal is extracted with the help of the

process of mining.

Coal and Coke

What is coke? All of us have had ‘coke’ i.e coca cola at some point or

the other in our lives. But is it the same? Well no, it is actually a type

of non- renewable fuel. Let’s us find out more about it.

Introduction to Coal

Coal is a black sedimentary rock occurring in coal beds and coal

mines. Coal is mined from these coal beds and mines. It takes millions

of years for its formation. It occurs naturally. When plants and dead

animals decay and get buried under the mud, carbon gets trapped in

the sediments and carbonizations take places.

Various types of coal are used for various types of purposes. For e.g.

thermal coal is used for the production of electricity or power. Steel

production uses coking steel. Activated carbon is used in filters and

water purification. Activated charcoal is used to make face packs and

toothpaste. Coal is also used for manufacturing and in cooking, for

example, barbecue. It helps to create alumina refineries. Products such

as resins, lubricants, certain hair shampoos, etc also contain coal in it.

What is Coke?

Coal has very few impurities in it known as coke and also has a high

carbon content. It has a solid state of matter. Its components are the

destructive distillation of low-ash, low-sulphur bituminous coal which

derives from carbonaceous material and can be found in nature;

usually a grey, porous and hard substance. It is also known as pet coke

or petroleum coke.

It is almost the pure form of carbo and it consists of carbon similar to

coal. Its calorific value (energy produced when 1 Kg of a fuel is burnt)

is about 56,000 kilojoules/kilogram and is more expensive than coal.

It is made in an airless furnace or oven temperatures as high as two

thousand degree Celsius but usually around one thousand to one

thousand one hundred degrees Celsius. This process eliminates the

volatile parts of the coal, such as tar, water, and gas.

Uses of Coke

The following are the uses of coke :

● It is used to reduce iron oxide to produce iron.

● It can be used in households as a clean fuel, relatively free of

smoke and impurities.

● In the past, it was often used in kitchen stoves.

● Coke is also used to produce water gas.

● It is used as a reducing agent in smelting iron ore.

● Even blacksmiths use it as a fuel in blacksmithing.

● In the sixties and seventies, it was used for house heating.

● It was used for domestic heating following the creation of

smokeless zones.

● Some people roast malted barley for use in their Scotch Whisky

burning a mixture of coke and peat.

● NASA used it as of the materials used in the heat shielding of

Apollo Command Module.

● It is also used as a synthetic gas.

Solved Example For You

Q. What is the calorific value (energy produced when 1 Kg of a fuel is

burnt) of Coke?

a. 65000 kilograms

b. 56000 kilograms

c. 560000 kilograms

d. 650000 kilograms

Sol: The calorific value of coke is 65000 kilograms or kilojoules.

Coal Tar and Coal Gas

By now, we already know about coal but coal is further filtered into

Coal Tar, Coal Gas and Coke. But what is a coal gas? And what is

coal tar? Let’s find out more about them below.

Coal Tar

Coal tar is a thick black liquid which is a by-product of the production

of coal gas and coke. It contains benzene, naphthalene, phenols,

aniline, and many other organic chemicals. Coal tar is used for

medical and industrial purposes. However, coal is also known as cutar,

balnetar, liquor carbonis detergens, liquor picis carbonis, etc.

Uses of Coal tar

The following are the uses of coal tar :

● Coal tar is used as the medication to heal itching, scaling, and

flaking due skin conditions.

● It is also used in making medicated shampoo to treat dandruff

and to kill lice.

● Soaps are made from coal tar.

● Various phenolic coal tars have the properties of a painkiller.

● Coal tar is used to protect and beautify the underlying

pavement.

● Coal is also used to make parking lot seal – coat products.

● Roads are made with the use of coal tar.

● Coal tar is flammable in nature. Hence, it is used for heating.

● Binders used in graphite industry to make green blocks have

coal tar in them.

● Manufacture paints, synthetic dyes, and photographic materials

contain coal tar.

Properties of Coal Tar

The following are the properties of coal tar :

● Coal tar is black in color.

● It’s a semi-solid and semi-liquid in nature and is less

permeable.

● Its density is very thick and It has a peculiar smell.

● Tar is insoluble in nature which means that it can’t dissolve in

water.

● It has a boiling point of two hundred to two hundred and

fifty-degree celsius.

● Its a fuel resistant and has more temperature susceptible than

asphalt cement.

Coal Gas

Coal gas is a mixture of gases i.e. hydrogen, methane, carbon

monoxide and volatile hydrocarbons procured by the destructive

distillation of coal. It is a flammable gas and is made from coal which

supplied via a piped system and is obtained from coal in the absence

of air and contains nitrogen and carbon dioxide.

Uses of coal gas

The following are the uses of coal gas:

● Coal gas is used in lighting.

● The gas is also used for heating.

● Most often than not many people use this gas for cooking.

● It is used as a fuel

● Coal gas is also used as an illuminant.

Formation of Coal Gas

Coal gas is procured from the distillation of soft coal and is a

by-product of coke. It does not have any fixed composition. Most of

the coal gas consists of hydrogen and methane with small amounts of

other hydrocarbons, carbon monoxide (a poisonous gas), carbon

dioxide, and nitrogen.

Solved Example For You

Q. Which of the following disease is cured by coal tar?

a. It is used to treat itching or scaling of the skin.

b. It is used to cure diarrhoea.

c. Coal Tar can heal deep wounds.

d. Fever and cold are treated with the help of coal tar.

Sol: Coal tar is used to treat itching or scaling of the skin. It is also

used to get rid of hair problems such as dandruff and lice.

Natural Gas

You know that you use coal for barbecue, but what type of gas do you

usually in your kitchen? Do you know that? Generally, natural gas is

used in the kitchen to cook food. But what is natural gas? How is this

formed? What are its uses? What are its properties? Let’s find out

more about it.

What is Natural Gas?

Natural Gas is a fossil fuel. It occurs naturally and approximately

consists of 95% hydrocarbon methane, the other 5% consists of

nitrogen, carbon dioxide, helium or hydrogen sulfide. It takes millions

of years for it to form.

The gas is formed when layers of decaying plants and animals are

buried under the earth’s surface and are exposed to intense heat and

pressure for millions of years. Plants originally obtain energy from the

sun and store in the form of chemical bonds in the gas. And thus, the

formation of this gas occurs.

Properties of Natural Gas

The following are the properties of Natural Gas :

● The state of matter of this gas is gaseous.

● It doesn’t have any color and is a tasteless gas.

● It is free of any kind of toxic, there is no smoke on burning and

it has high calorific value.

● The gas is odorless. However, a chemical called mercaptan is

added to it in small amounts to give it distinctive smell of eggs.

This helps to find out any gas leaks.

● It is a combustible gas and a fossil fuel.

● Its a mixture of simple hydrocarbon compounds.

● It contains primarily methane, along with small amounts of

ethane, butane, pentane, and propane.

● The by-products of this gas are water vapor and carbon

dioxide.

● Air is 60% heavier than natural gas.

● It has a low flammability range and a high ignition

temperature.

● Generally, it is transported through pipes.

● It occurs naturally in the rocks beneath the earth’s surface, in

sedimentary rocks that are porous.

Uses of Natural Gas

The following are the uses of natural gas :

● It is used in vehicles in the form of CNG (Compressed Natural

Gas).

● It is also used to manufacture a few chemicals and fertilizers.

● The gas is used as a source of energy for cooking, heating, and

electricity generation.

● It is used as chemical feedstock for manufacturing plastic and

other commercially important organic chemicals.

● The gas is also useful in the production of fabrics, glass, paint,

plastic, steel, etc.

● Hydrogen can also be produced with the help of it.

● Protein-rich animal and fish feed is produced by feeding this

gas on a commercial scale.

Solved Example For You

Q. Which of the following statements is not true about Natural Gas?

a. The gas is colorless.

b. This as is tasteless.

c. It is used as a source of energy for cooking, electricity

production and heating.

d. It has a peculiar smell.

Sol: Statement d is false because natural gas is odorless when found in

nature. But late on, chemicals are added to give it a distinctive smell to

prevent gas leaks.

Petroleum Refining and Formation Process

Petroleum refining or Oil refining is an industrial process in which

crude oil is extracted from the ground and transformed and refined

into useful products like Liquefied Petroleum Gas (LPG), kerosene,

asphalt base, jet fuel, gasoline, heating oil, fuel oils etc. Crude Oil

consists of hydrocarbon molecules. There are three steps in the

Petroleum refining process – Separation, Conversion, and Treatment.

It would not be possible to travel by vehicle without petrol or diesel

oil. Learn how do we obtain petrol and crude oil and also more about

petroleum or oil refineries.

What is Petroleum?

Petroleum is a substance that occurs naturally. It is a dark liquid. It

occurs beneath the earth’s surface. A large number of products like

petrol, diesel, lubricating oil, etc derive from petroleum. Its

compounds can be separated with the help of fractional distillation. In

the year 2006, primary sources of energy consisted of petroleum

36.8%, natural gas 22.9%, and coal 26.6% share for fossil fuels in

primary energy production in the world.

Formation of Petroleum

It takes around millions of years for petroleum to form. It is formed

due to the presence of decomposed carcasses of dead animals beneath

the surface of the earth. These carcasses of dead animals are subjected

to extreme pressure and heat. Over centuries, millions of animals lived

and died to become fossilized, just in case of plant-based matter.

Similarly, in the ocean, oceanic creatures drowned to the bottom of the

ocean and got buried under the sand and rocks.

Decayed due to the presence of bacteria, the decomposed organic

matter got buried deeper and deeper over the years. Over millions of

years, high temperature, high pressure, the absence of air converted

the dead animals to petroleum and coal. This liquefied form of dead

organic matter is petroleum or crude oil. Crude oil is extracted from

oil wells, these wells can be very deep. The oil extracted is later

refined to form petrol, diesel, aviation fuel, paraffin wax, lubrication

oil, etc.

Petroleum Refining Process

Deposition of petroleum occurs with natural gas in the rocks called oil

wells from where it is taken out by drilling. Refining is a process

where the separation of various compounds of crude oil occurs.

Fractional distillation is a process used to separate its compounds.

Crude Oil procured from an oil well is a mixture of many liquids.

Different temperature evaporates a different liquid. This temperature

is the boiling point of that liquid. The crude oil is heated to a

temperature of 400-degree Celcius, is fed in at the bottom of the

column and heated further. The liquid with the lowest boiling point

changes into vapor first and condenses. At higher temperature, the

next volatile liquid changes into a vapor state and rises.

Petroleum Refining Process Flow Chart

Source: Wikipedia

Different vapors rise at different temperature and as they condense,

they are collected in different trays. Different liquids are collected in

different trays. A few gases reach the top of the column without

condensing.

Products produced in Petroleum Refining Process

● Petroleum Gas: Generally, liquefied petroleum gas is useful for

domestic fuel.

● Gasoline: Procuration of petrol occurs from this fraction.

● Kerosene: It is used as domestic fuel and also as fuel in jet

engines.

● Diesel oil or light oil: It is useful in the automobile industry.

● Heavy Oil or Lubricating Oil: This type of oil is used in

making lubricating oils.

● Fuel Oil: It is essential for ships, central heating, and factories.

● Residue: We can procure products like paraffin wax, bitumen

from this residue. It is useful for making roads and roofing.

Solved Example For You

Q: Which of the following has the lowest boiling point?

a. Butane and Propane

b. Petrol

c. Diesel

d. Kerosene

Ans. Butane and Propane have the lowest boiling point, followed by

petrol, kerosene, and diesel.