1.1. Bottom Ash Ash is discharge from the bottom of the combustor to
maintain the required inventory. Higher bed pressure drop as an indication of
accumulation of over sizeparticle-mostly stones,
shale, and agglomerated ash. Usually bottom ash draining is periodically
operation as the bed ash quantity is generally <10%>
1.2. Ash Screw Cooler
Water-cooled ash screw cooler shown in figure.1 below, is a good solution for
dry ash discharge that isenvirontmentally more more acceptable. Ash from the bed is drained into
screw whose flights, shaft and casing are all cooled by softened water of high
quality.
Figure.1 Ash Screw Cooler
1.3. Holo-Flite
dryer / screw cooler
Metso's Holo-FliteŽ thermal processor is an indirect heat exchanger
utilizing a hollow screw for heating, cooling or drying bulk solids, filter
cakes, pastes or sludges. It is a proven and
efficient thermal processor with over 3000 installations worldwide.(http://www.metso.com)
In the Metso Holo-FliteŽ processor, individual particles are heated or
cooled as they come in contact with the surfaces of the hollow flights, shaft
and trough. The product to be processed is continuously conveyed in an axial
direction by means of the rotating screw fl ights along a jacketed trough.
Figure.2 Ash Screw Cooler -
Hollow Flite