Paper Technology Journal 17 - Voith

Lightweight contaminants
containing fibers
Filtrate
Newsprint
Corrugating medium
Graphic papers
Inlet
Market price
per ton paper
(typical values)
500 Euro
300 Euro
1000 Euro
Heavyweightcontaminants
This is where meri Entsorgungstechnik
GmbH, a joint venture company between
Voith Paper Fiber Systems and meri Anlagentechnik,
can help, using experience
gathered from 30 complex rejects handling
systems in operation, and more
than 600 machines installed in the paper
industry. Meri provides the papermaker
with tailor-made subsystems as well as
special machine technology.
It should not be forgotten that the filtrates
from the rejects/sewer zone represent
an important interface with the water
system of the overall plant and therefore
they have to be taken into consideration
for a complete overall view.
Standards set by legislation are increasingly
influencing the design of rejects
handling systems. Since specific disposal
6
Total non-paper
production losses
(typical values)
18 %
5 %
25 %
Fiber Systems
Amount sent to
landfill per ton paper
at 60% dry content
300 kg
83 kg
416 kg
costs nowadays can amount to around
5 % of earnings from paper production
(Fig. 9), investment in an optimized rejects
handling system should be viewed
with great interest from an ROI point of
view. The potential savings from an increased
rejects dry content alone can be
tremendous (Fig. 10).
When designing new plants, the following
should be considered:
● Include rejects handling in the overall
concept as early in the design stage as
possible
● Define present and future options for
rejects disposal
● Allow for future expansion of the
rejects handling system from the
outset
Fig. 6: 3D function layout for the Sediphant.
Fig. 7: Heavyweight fraction after removal and
dewatering with the Sediphant.
Fig. 8: Lightweight fraction from the Sediphant
after further dewatering.
Fig. 9: Example of disposal costs as a percentage
of the earnings from paper production for
various paper grades.
● Integrate metal separation and rejects
size reduction
● Allow good accessibility for operation
and maintenance
● Regard the rejects handling as an
integrated system.
Example (Fig. 11)
13
7 8
Landfill costs
per ton paper at
100 Euro/t
30 Euro
8 Euro
42 Euro
Disposal costs
as a percentage
of earnings
6.0 %
2.7 %
4.2 %
This recent example describes a state-ofthe-art
rejects handling system in a
newsprint production line where a drum
pulper is installed. The objective was to
prepare the rejects for incineration in a
given particle size, and to minimize the
incombustible content. The concept must
ensure continuous pulper operation even
during shutdowns in the rejects system
or when maintenance work is required
here.
17/04
9