Paper Technology Journal 17 - Voith

10
14
Fig. 10: Relationship between disposal costs
per ton paper and dry content of the rejects going
to landfill.
Graphic papers
Newsprint
Corrugating medium
Fig. 11: Example of a complete rejects
handling system for preparing the rejects for
incineration.
A Dinoscreen is used for removing
coarse contaminants from the sewer
channel, dumping them into a separate
container. Rejects from HD and LD cleaning
and from slot screening are dewatered
in a Sediphant. The heavyweight
material from the Sediphant is also discharged
into a separate container.
The complete rejects from the drum
pulper are collected on a conveyor. A
metal detector removes large pieces of
metal, which are dumped into a container
by reversing the conveyor direction. A
magnetic separator, located above the
conveyor, removes ferrous metal, also
dumping it into a container.
The rejects are then shredded into small
pieces in a Lion shredder. Rails allow the
shredder to be moved into a maintenance
position without interrupting operation of
the rejects handling system. A second
magnetic separator then removes any remaining
ferrous metal from the conveyor
feeding the post-shredding stage. Here,
two Lion shredders operate one above
the other and at 90° to each other. These
17/04
80
70
60
50
40
30
20
10
Disposal costs per ton paper Euro
30 40 50 60 70
Dry content of the rejects going to landfill (in %)
Automatic container
loading station
Further
reduction
in size
reduce the rejects to the required size.
The feed conveyor can be swung so that
the post-shredding and the subsequent
compactor stages can be bypassed.
In normal operation the shredded material
is dewatered with a Compax reject
compactor, achieving a dry content of
more than 60 %. After compacting, the
rejects are distributed automatically into
four containers. A movable conveyor
equipped with sensors can fill every container
from several positions so that all
four container capacities are used to the
full. The rejects are now suitably ready
for incineration.
Up to now, most of the examples of complex
rejects handling systems are in
Europe, but in other countries there is an
increasing need to pay more attention to
rejects handling. This is motivated either
by the need to reduce operating personnel
or to simplify disposal and make it
more cost efficient.
Compax
Sediphant
Dinoscreen
Initial reduction in size
Magnetic separators 1+2
Drum pulper
11