Coal Gasification

• 03 Feb 2022

For Prelims: Coal Gasification, Syngas, Hydrogen Economy, Concerns Associated with Coal Gasification Plants

For Mains: Coal Gasification, Syngas, Hydrogen Economy, Concerns Associated with Coal Gasification Plants

Why in 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?

• Process: 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.
• Production of Syngas: 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.
• Significance: 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.

What is the Hydrogen Economy?

• It is an economy that relies on hydrogen as the commercial fuel that would deliver a substantial fraction of a nation’s energy and services.
• Hydrogen is a zero-carbon fuel and is considered an alternative to fuel and a key source of clean energy.
• It can be produced from renewable sources of energy such as solar and wind.
• It is an envisioned future where hydrogen is used as fuel for vehicles, energy storage and long-distance transport of energy.
• The different pathways to use hydrogen economy includes hydrogen production, storage, transport and utilization.
  • In 1970, the term 'Hydrogen Economy' was coined by John Bockris.
  • He mentioned that a hydrogen economy can replace the current hydrocarbon-based economy, leading to a cleaner environment.

What are the Concerns associated with Coal Gasification Plants?

• Environmental Perspective: 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.
• Efficiency Perspective: 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.

Source: DTE