Coal Gasification

2022 FEB 4

Preliminary   > Science and Technology   >   Energy   >   Clean energy

Why in news?

  • The Centre proposed four coal gasification-pilot projects in the Union Budget 2022-23.
  • According to the CSE, the process of coal gasification is not attractive from a climate change point of view.

What is Coal Gasification?

Underground Coal Gasification (UCG):

In-situ gasification of coal or Underground Coal Gasification (UCG) is the technique of converting coal into gas while it is still in the seam and then extracting it through wells.

  • Coal gasification is a process in which coal is partially oxidised with air, oxygen, steam or carbon dioxide to form a fuel gas.
  • This gas is then used instead of piped natural gas, methane and others for deriving energy.
  • During gasification, coal is blown with oxygen and steam while also being heated under high pressure. During the reaction, oxygen and water molecules oxidize the coal and produce syngas.

What is Syngas?

  • Syngas, or synthesis gas, is a fuel gas mixture consisting primarily of hydrogen, carbon monoxide, carbon dioxide and water vapor.
  • Syngas is usually a product of coal gasification and the main application is electricity generation. Syngas is combustible and can be used as a fuel of internal combustion engines.
  • Syngas can be used to produce a wide range of fertilizers, fuels, solvent and synthetic materials.

Benefits of coal gasification:

  • Transporting gas is a lot cheaper than transporting coal.
  • Help address local pollution problems.
  • Has greater efficiency than conventional coal-burning because it can effectively use the gases twice:
    • The coal gases are first cleansed of impurities and fired in a turbine to generate electricity.
    • The exhaust heat from the gas turbine can be captured and used to generate steam for a steam turbine-generator.
  • Steel companies typically use coking coal in their manufacturing process. Most of the coking coal is imported and is expensive. To cut costs, plants can use syngas, which comes from coal gasification plants in the place of coking coal.
  • The hydrogen obtained from coal gasification can be used for various purposes such as making ammonia, powering a hydrogen economy.

PRACTICE QUESTION:

Which of the following statements is/are correct?

1. Syngas is a product of coal gasification

2. Syngas can be used as a fuel of internal combustion engines.

Select the correct answer using the code given below:

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Answer