There are three methods of ash handling equipments. One of them is pneumatic ash handling equipment. Pneumatic system is rarely used to transport bottom ash; it is only used for small scale boiler. Pneumatic ash handling system is often employed for carrying out fly ash.
For more detail please see figure 1 below:
|Figure 1: Pneumatic Ash Handling Equipment|
Source: Book - Central Boiler Plants - Headquarter Department of The Army
At the figure above explain pneumatic ash handling system with vacuum type. Vacuum pump which is driven by motor is installed into exhauster to generate vacuum pressure. Ash which had been collected by the hopper will be distributed to the pneumatic ash handling system. The exhauster generate suction to make air flow in the line pipe rapidly, so dry ash will be induced and flow to primary collector and secondary collector. The collector is completed by counter balance drop door which allow the ash put down into storage bin firmly and periodically.
The counter balance drop door is normally sealed and closed to maintain the system in the negative pressure. The system is running cycle and periodically, to open the drop door the pressure will be made similar, so the ash can drop into storage bin.