There are three types of ash handling system; pneumatic, hydraulic and mechanical ash handling system. Hydraulic ash handling equipment is usually used to convey bottom ash. Illustration below is sample of working principal on hydraulic ash handling equipment.
|Figure 1: Hydraulic Ash handling Equipment|
Source: Book - Central Boiler Plants - Headquarter Department of The Army
The hydraulic system applies high pressure water jet to take bottom ash from hopper which was located under steam boiler or under stoker. The bottom ash can be taken out from the hopper by instruments such as water jet nozzle and spray nozzle. The bottom ash is then distributed by water jet through sluice way to wet storage sump (see Figure 1).
The treatment to dispose ash is different for fly ash. Fly ash from the hoppers is disposed pneumatically by water jet exhausters then distribute to air separator to separate air from fly ash and then air will be discharged to atmosphere. The end of process, the mixture fly ash and water are conveyed to wet storage sump (see Figure 1).
Another type of ash handling system is mechanical ash handling equipment. This equipment can be employed for small scale boiler which uses stoker type. This type can be also used to convey both for fly ash and bottom ash. The system use mechanical equipments such as bucket conveyor, screw, drag to convey ash from steam boiler to container or silo or storage bin.