Focus: GS-III Environment and Ecology, Industry and Infrastructure
Why in news?
NTPC Ltd., a central PSU under Ministry of Power and country’s largest power generation company, has developed an infrastructure at Rihand project in Uttar Pradesh to transport fly ash in bulk to cement plants, located at distance, at a cheaper cost.
- The effort marks the beginning of a new era for the transportation of fly ash from a remote location to a consumption centre, enabling power plants for upgrading the utilization of fly ash with the availability of additional material loading avenues for Indian Railways and accessibility of fly ash to the cement plants in an environment-friendly manner at a competitive price.
- NTPC is looking at new avenues of fly ash management like fly ash based geo-polymer road, use of bottom ash as replacement of fine aggregate (sand) in cement concrete.
- The development is in line with NTPC’s commitment towards 100 percent utilization of fly ash from power plants.
- Fly ash or flue ash (aka pulverised ash) is a coal combustion product that is composed of the particulates (fine particles of burned fuel) that are driven out of coal-fired boilers together with the flue gases.
- Ash that falls to the bottom of the boiler’s combustion chamber (commonly called a firebox) is called bottom ash and is easily collected.
- In modern coal-fired power plants, fly ash is generally captured by electrostatic precipitators or other particle filtration equipment before the flue gases reach the chimneys.
- Depending upon the source and composition of the coal being burned, the components of fly ash vary considerably, but all fly ash includes substantial amounts of Silicon Dioxide (SiO2) (both amorphous and crystalline), Aluminium Oxide (Al2O3) and Calcium Oxide (CaO), the main mineral compounds in coal-bearing rock strata.
- In the past, fly ash was generally released into the atmosphere, but air pollution control standards now require that it be captured prior to release by fitting pollution control equipment.
About 43% is recycled, often used as a pozzolan to produce hydraulic cement or hydraulic plaster and a replacement or partial replacement for Portland cement in concrete production.