NTPC Ltd, a central PSU under Ministry of Power and the 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 development is in line with NTPC’s commitment towards 100% utilization of fly ash from power plants.
Fly Ash Utilization
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. During the financial year 2019-20, almost 44.33 million tonnes of fly ash was utilized for various productive purposes, being 73.31% of the ash generated.
Moreover, the company 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. Also, NTPC has plans to set up a fly ash classifier unit for export purposes. With a total installed capacity of 62.9 GW, NTPC group has 70 power stations comprising 24 coal, 7 combined cycle gas/ liquid fuel, 1 hydro, 13 renewables along with 25 subsidiary & JV power stations. The group has over 20 GW of capacity under construction, including 5 GW of renewable energy projects.
Fly ash is the finely divided residue that results from the combustion of pulverized coal and is transported from the combustion chamber by exhaust gases. Fly ash is produced by coal-fired electric and steam generating plants. Typically, coal is pulverized and blown with air into the boiler’s combustion chamber where it immediately ignites, generating heat and producing a molten mineral residue. Boiler tubes extract heat from the boiler, cooling the flue gas and causing the molten mineral residue to harden and form ash. Coarse ash particles, referred to as bottom ash or slag, fall to the bottom of the combustion chamber, while the lighter fine ash particles, termed fly ash, remain suspended in the flue gas. Prior to exhausting the flue gas, fly ash is removed by particulate emission control devices, such as electrostatic precipitators or filter fabric baghouses.
Fly ash utilization, especially in concrete, has significant environmental benefits including:
- increasing the life of concrete roads and structures by improving concrete durability
- net reduction in energy use and greenhouse gas and other adverse air emissions when fly ash is used to replace or displace manufactured cement
- reduction in amount of coal combustion products that must be disposed in landfills
- conservation of other natural resources and materials