Thermal power plants that generate electricity by burning coal also produce a lot of residue ash as a waste material, which needs to be properly disposed-off from the Plant.
Since almost 40% of coal is converted to ash, a large amount of ash is continuously being generated and is present in various forms in the power plant, due to which an efficient ash handling process is required for optimal performance of the power plant.
Ash handling system is a set of methods by which ash can be cooled down to manageable temperature, transferred to a disposal areas or storage container and further utilized in other industries.
As the operating conditions of power plants are extremely harsh and corrosive, Ash handling systems must be designed and developed in such a manner that they are able to withstand heavy wear and tear, occasional system failures and high-volume transportation and storage.
Almost 80% of ash generated in power plant is Fly ash and generally is in form of very fine particles. It is collected via apparatus such as economizer hoppers, air pre-heater hoppers, electrostatic precipitators and dust collectors positioned in the flue gas processing system.
Bottom Ash is generated below the furnace of steam generator and accounts for around 20% of total ash generated in a power plant. Bottom ash is mostly coarse in nature hence it needs to be further crushed in grinders and crushers before being transported to ash handling systems.
Ash handling systems deploy several types of pneumatic conveyors or mechanical conveyors or slurryfication depending on type of ash being handled. Ash handling systems are generally divided into following types:
This combination of economizer, air-preheater and electrostatic precipitators are used to capture and transfer fly ash into fly ash silos
A. HIGH CONCENTRATION ASH SLURRY DISPOSAL SYSTEM -
B. LEAN ASH SLURRY DISPOSAL SYSTEM -