Paper Technology Journal - Voith

Fig. 1: View of the RCF plant buildings
in Kemsley.
The recovered paper warehouse can
store up to 15,000 tonnes. All main stock
preparation machines as well as the
water treatment equipment are located
in the machine building, with a floor
area of 7600 m2 . Fig. 1 shows the machine
building with the adjacent warehouse
for recovered paper.
In the surrounding industrial zone, two
large paper mills are located quite nearby.
This enabled us to enter into an appropriate
service contract with the service
organization already supplying the
two paper mills with power and steam
and also taking care of effluent and
waste material disposal. Total investment
for the deinking plant was 43 million
pounds Sterling. Plant capacity is
110,000 tonnes per year finished stock.
This requires processing approx.
180,000 tonnes of recovered paper per
year. The recovered paper consists of
unsorted, mixed office papers. To
achieve the necessary tonnage, the plant
must operate 363 days per year.
Chronology of the plant construction
Construction work started in September
1994 with the demolition of unused
buildings, and the foundations were laid
in October 1994. The first machines were
installed in March 1995 and installation
of the plant was completed by September
1995. The first phases in commissioning
the plant then began, and production
of deinked pulp started on the 11th of
Stock Preparation
Table 1: Process data
Pulping consistency 18 - 22%
Specific pulping energy 28 - 30 kWh/t
Reductive bleaching 0.65% stabilized dithionite (Hy-Brite)
Oxidative bleaching 1.3% peroxide (H2O2, 100%)
Flotation additives 1% soap + 0.01% synthetic foaming agent
Overall specific dispersion energy 160 - 180 kWh/t
Table 2: Quality comparison
Parameters Unit UKP 100% SF 50% SF chem.pulp 100% LF 100% SF/CTMP
DIP chem. pulp 50% LF chem. pulp chem. pulp (bleached)
Brightness % ISO with UV 100 91 90 90 85
% ISO w/out UV 86.5 91 90 90 85
Dirt speck mm2 /m2 4-6 1-5 1-5 1-4 1-6
area (ppm)
Stickies mm2 /kg < 80 < 20 < 20 < 20 < 40
Freeness
Tensile
CSF 400 460 420 500 470
index
Tear
N · m/g 50 49 66 81 41
index mN · m2 Burst
/g 10.8 7.1 10.9 11.1 9.3
index kPa · m2 /g 3.3 3.8 5.8 7.8 2.9
(SF = short fibre, LF = long fibre)
November 1995. At the end of January
1996 optimization work commenced. The
amount of sludge “produced” annually
in the RCF plant is 70,000 tonnes. It
comes out of the system with a dry content
of 60% and is used to improve
neighbouring agricultural land. This form
of sludge utilization is carried out under
the supervision of the government
authority ADAS (Agricultural Develop-
11
ment and Advisory Service). The average
content of inorganic components (ash) in
the sludge is around 70%. Apart from
sludge, some 3% of plastic and metal
waste is removed and then disposed of
on the communal rubbish dump.
Finished stock production was 73,000
tonnes in 1996, the first year of operation,
and production for 1997 was set at