Coal Gasification

News: Recently, the Delhi-based non-profit, Centre for Science and Environment (CSE), has raised concerns about the Union Government’s announcement on coal gasification projects in the Budget 2022-23. The budget proposed four pilot projects for coal gasification and conversion of coal into chemicals required for the industry. According to CSE, the process of coal gasification is not attractive from a climate change point of view.

What is Coal Gasification?

  • 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.
  • 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.
  • It produces Syngas which is a mixture consisting primarily of methane (CH4), carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2) and water vapour (H2O). Syngas can be used to produce a wide range of fertilizers, fuels, solvent and synthetic materials.
  • 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.
  • It is primarily used for electricity generation, for the production of chemical feedstocks.
  • The hydrogen obtained from coal gasification can be used for various purposes such as making ammonia, powering a hydrogen economy.

Concerns:

  • Coal gasification actually produces more carbon dioxide than a conventional coal-powered thermal power plant. According to CSE estimates, one unit of electricity generated by burning gasified coal generates 2.5 times more carbon dioxide than what would result when burning the coal directly.
  • The syngas process converts a relatively high-quality energy source (coal) to a lower quality state (gas) and consumes a lot of energy in doing so. Thus, the efficiency of conversion is also low.