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Pellet operation
Fuel store
11.4
Pellet operation
Wood chip boiler with pellet operation
If there is little space for a wood chip store, pellets are
the ideal solution, as the energy density of pellets is
about four times as high as that of wood chips. So for
the same heat output you only need a quarter of the
storeroom.
A boiler with an output of 45 kW requires approximate-
ly 15 tons of pellets per year, which corresponds to a
storage space size of 23 m³. For annual filling, a
storeroom volume of just 30 m³ including a pellet
reserve is sufficient.
For the fuel discharge, either an agitator or a
pellet discharge screw can be used.
Special requirements apply to pellet storage
rooms. For more information, please contact
ETA.
Floor agitator for pellets
For pellet operation with a floor agitator, the following
points must be observed:
•
Pellets are much heavier than wood chips. Which
is why floor agitators may only be filled with pellets
up to a height of 2 metres.
•
To ensure that the pellets are not damaged, only
floor agitators up to a maximum of 4 metres in
diameter may be used, and the angle of inclination
may not exceed 12°.
•
A special cover plate for pellets is needed on the
open trough screw in the store to prevent overfilling
of the discharge screw.
•
The trough screw between store outlet and boiler
may be a maximum of 1.5 metres long.
Fig. 11-5: Floor agitator for pellets
Pellet discharge screw
If the boiler is operated exclusively with pellets, then a
pellet discharge screw is the better solution. This is
due to the fact that more pellets can be filled with this
solution. Please note that the screw must be routed to
the boiler for this conveying system. The maximum fill
height for a pellet discharge screw is 7 m.
Fig. 11-6: Discharge screw for pellets
