Coal

Materials used for our basic needs can be broadly classified into natural resources (found in nature) and man-made resources (created by humans). Natural resources themselves can be further divided into inexhaustible (unlimited in nature, like sunlight and air) and exhaustible (limited in amount, can be used up by human activities, like forests, wildlife, minerals, coal, petroleum, and natural gas).

Coal is a common fuel. It is a hard, black substance that resembles stone.

Historically, coal was used in railway engines to produce steam power. It is also used in thermal power plants to generate electricity and serves as a fuel in various industries.

---

Story Of Coal

Coal is a fossil fuel, formed over millions of years from the remains of dead vegetation. Approximately 300 million years ago, dense forests covered low-lying wetland areas on Earth. Due to natural events like flooding, these forests were buried under layers of soil. As more soil accumulated over them, the vegetation was compressed. The buried organic matter was also subjected to high temperatures and pressures as it sank deeper. Under these extreme conditions and in the absence of air, the dead plants slowly transformed into coal. This slow process of converting dead plant material into coal is called carbonisation. Since it originated from dead vegetation (fossils), coal is classified as a fossil fuel.

When coal is heated in air, it burns and primarily produces carbon dioxide gas.

In industry, coal is processed to obtain several useful products:

---

Coke

Coke is a product derived from coal. It is a tough, porous, and black substance that is an almost pure form of carbon. Coke is an important material used in the manufacturing of steel and in the process of extracting many metals from their ores.

---

Coal Tar

Coal tar is another product obtained from coal processing. It is a thick, black liquid with a strong, unpleasant odour. Coal tar is actually a complex mixture containing about 200 different chemical substances. These substances obtained from coal tar are used as starting materials for manufacturing a wide variety of products used in daily life and industry, including synthetic dyes, drugs, explosives, perfumes, plastics, paints, photographic materials, and roofing materials. Even naphthalene balls, commonly used to repel moths, are derived from coal tar.

Historically, coal tar (or a similar pitch) was used for road surfacing. Nowadays, bitumen, which is a product of petroleum refining, is more commonly used for metalling roads.

---

Coal Gas

Coal gas is obtained as a byproduct during the processing of coal to produce coke. This gas is combustible and is used as a fuel in many industries, especially those located near coal processing plants. Coal gas was one of the earliest fuels used for street lighting in cities like London (1810) and New York (around 1820), although today its primary use is as a source of heat.

Petroleum

Petrol and diesel are crucial fuels used for transportation – petrol for light vehicles like cars, motorcycles, and scooters, and diesel for heavier vehicles like trucks and tractors. These fuels are obtained from a naturally occurring resource called petroleum. The name 'petroleum' comes from Latin words: 'petra' meaning rock, and 'oleum' meaning oil. This name reflects that petroleum is found and extracted from between layers of rocks deep underground.

---

Formation Of Petroleum

Petroleum was formed from the remains of tiny organisms that lived in the sea millions of years ago. As these organisms died, their bodies sank and settled at the bottom of the ocean. Over vast periods, these remains were covered by layers of sand and clay. Under high pressure, high temperature, and the absence of air, the dead organisms were slowly transformed by chemical and biological processes into petroleum and natural gas over millions of years.

Petroleum and natural gas deposits are often found together, trapped between impervious rock layers. Notably, the layer containing oil and gas is typically found above the water layer because oil and gas are lighter than water and do not mix with it.

The first oil well in the world was drilled in Pennsylvania, USA, in 1859. In India, oil was first discovered at Makum in Assam in 1867. Today, oil is found in various regions across India, including Assam, Gujarat, Mumbai High (offshore), and in the river basins of Godavari and Krishna.

---

Refining Of Petroleum

Petroleum, as extracted from the ground (crude oil), is a dark, oily liquid with an unpleasant smell. It is not a single substance but a complex mixture of various components or constituents. These include petroleum gas (LPG), petrol, diesel, kerosene, lubricating oil, paraffin wax, and bitumen.

The process of separating these different components or fractions from crude petroleum is called refining. Refining is carried out in large industrial facilities known as petroleum refineries.

Each component obtained from refining petroleum has specific uses, as detailed below:

S.No.	Constituent of Petroleum	Uses
1.	Petroleum Gas in Liquid form (LPG)	Fuel for homes and industry
2.	Petrol	Motor fuel, aviation fuel, solvent for dry cleaning
3.	Kerosene	Fuel for stoves, lamps, and jet aircrafts
4.	Diesel	Fuel for heavy motor vehicles, electric generators
5.	Lubricating oil	Lubrication
6.	Paraffin wax	Ointments, candles, vaseline, etc.
7.	Bitumen	Paints, road surfacing

Many valuable substances are derived from petroleum and natural gas. These are collectively referred to as petrochemicals. Petrochemicals are essential in the manufacturing of detergents, various synthetic fibres (like polyester, nylon, acrylic), polythene, and other man-made plastics. Hydrogen gas, often obtained from natural gas, is used in the production of fertilisers such as urea.

Given its vast commercial importance and the numerous valuable products derived from it, petroleum is often called 'black gold'.

Natural Gas

Natural gas is a significant fossil fuel that is easy to transport through pipelines. It is stored under high pressure as Compressed Natural Gas (CNG). CNG is increasingly used for power generation and as a fuel for vehicles because it is a less polluting and cleaner fuel compared to petrol and diesel.

A major advantage of natural gas is that it can be supplied directly to homes and factories through pipelines for burning, eliminating the need for transportation in cylinders. Pipeline networks for natural gas distribution exist in cities like Vadodara (Gujarat), parts of Delhi, and other areas.

Natural gas also serves as a starting material for manufacturing various chemicals and fertilisers. India has substantial reserves of natural gas, found in regions like Tripura, Rajasthan, Maharashtra, and the Krishna Godavari delta.

The formation of fossil fuels like coal, petroleum, and natural gas in the laboratory from dead organisms is not possible. Their formation is an extremely slow process that takes millions of years under specific conditions of pressure and temperature that cannot be replicated in a laboratory setting.

Some Natural Resources Are Limited

As discussed earlier, fossil fuels (coal, petroleum, natural gas), forests, and minerals are exhaustible natural resources, meaning their reserves are limited and can be depleted by human consumption. While it took millions of years for dead organisms to be converted into these fuels, the known reserves are estimated to last only for a few hundred years at current consumption rates.

Furthermore, burning fossil fuels is a major source of air pollution and contributes significantly to global warming by releasing greenhouse gases like carbon dioxide. Therefore, it is crucial to use these fuels judiciously and only when necessary.

Using fossil fuels efficiently and only when needed offers several benefits:

• Leads to a better environment due to reduced pollution.
• Reduces the risk associated with global warming.
• Ensures the availability of these valuable resources for a longer period for future generations.

In India, organisations like the Petroleum Conservation Research Association (PCRA) provide advice on how to conserve petrol and diesel while driving. Their tips include:

• Driving at a consistent and moderate speed whenever possible.
• Switching off the vehicle engine at traffic lights or when waiting.
• Ensuring correct tyre pressure, as under-inflated tyres increase fuel consumption.
• Performing regular maintenance on the vehicle to ensure optimal performance and fuel efficiency.

Answer:

Answer:

Answer:

Answer:

Answer:

Answer:

Answer:

Answer:

Answer: