Screw Cooler for CFB Boilers
The screw coolers are typically designed to handle boiler ash with a discharge temperature of up to 950℃ and cooling it down to
200℃ or less so it can be transported pneumatically or mechanically to the ash silos.
Songling's screw cooler uses a rotating helical screw blade coiled around a shaft within jacketed U-trough, to move and cool ash and often used at a slight incline. The rate of volume transfer is proportional to the rotation rate of the shaft. The rotation speed is regulated through VFD.
There are two types of internal design of screw coolers depending on the ash rate to be handled: i) Solid flight design: the heat transfer surface is provided by jacketed trough and shaft.
ii) Hollow flight design: the hollow flights allows the cooling medium to flow through the flights for increased heat transfer surface area.