Destructive Distillation: An Overview

Destructive distillation is a process used to separate various components from a substance by heating it in the absence of air or oxygen. This method is commonly employed to extract useful products from organic materials such as coal and petroleum. In the case of coal, destructive distillation produces coke, coal gas, coal tar, and ammoniacal liquor. Similarly, in the case of petroleum, it yields gasoline, diesel, kerosene, and other valuable byproducts.

Destructive Distillation of Coal

During the destructive distillation of coal, the substance is heated in a furnace or retort to high temperatures between 900°C and 1100°C. This process breaks down the complex organic compounds present in coal into simpler and more useful substances. The main products obtained from destructive distillation of coal are:

1. Coke: It is a hard, porous, and carbon-rich material left behind after the volatile components of coal have been driven off. Coke is primarily used as a fuel in industries like iron and steel manufacturing.

2. Coal Gas: This is a mixture of several gases, including methane, hydrogen, carbon monoxide, and carbon dioxide. Coal gas is often used as a source of fuel for heating and lighting purposes.

3. Coal Tar: It is a thick, black, and sticky liquid that contains various organic compounds. Coal tar is widely used in the production of dyes, medicines, pesticides, and synthetic materials like plastics and fibers.

4. Ammoniacal Liquor: This is a byproduct obtained during the destructive distillation of coal. It contains ammonia and is used in the manufacturing of fertilizers and other chemical products.

Destructive Distillation of Petroleum

Petroleum is a complex mixture of hydrocarbons, and destructive distillation can be used to separate it into different fractions. The process involves heating petroleum to high temperatures, typically around 400°C to 600°C. The main products obtained from destructive distillation of petroleum are:

1. Gasoline: Also known as petrol, it is a volatile fuel primarily used in internal combustion engines.

2. Diesel: It is a heavier fuel with a higher boiling point than gasoline. Diesel is commonly used in diesel engines for vehicles and machinery.

3. Kerosene: This is a fuel used in lamps, stoves, and jet engines.

4. Other Byproducts: Destructive distillation of petroleum also yields various other byproducts such as lubricating oils, waxes, asphalt, and bitumen.

Conclusion

Destructive distillation is an important process for separating valuable components from organic materials like coal and petroleum. It allows us to obtain useful products such as coke, coal gas, coal tar, ammoniacal liquor from coal, and gasoline, diesel, kerosene, and other byproducts from petroleum. This process plays a crucial role in industries like energy production, manufacturing, and chemical synthesis.

The process of heating of coal in the absence of air is called as destructive distillation of coal. The products obtained on destructive distillation of coal are coke, coal gas, coal tar, and ammoniacal liquor.