Promoting Resource Efficiency in Small & Medium size ... - UNEP

Type of mill
Integrated machine finished newsprint (100% TMP (thermo mechanical
pulp))
Process heat consumption (net) in
GJ/ADt 1
- 1.3 2 2.2
Integrated magazine paper (100% TMP) - 0.3 2 2.1
Integrated newsprint (> 50% mechanical pulp) 0 – 3.0 2.0 – 3.0
Integrated lightweight coated paper (LWC) mill (> 50% mechanical pulp) 3.0 – 12.0 1.7 – 2.6
Integrated super calendared (SC) mill (> 50% mechanical pulp) 1.0 – 6.0 1.9 – 2.6
Integrated cardboard (> 50% mechanical pulp) 3.5 – 13.0 2.3 – 2.8
Non-integrated chemical thermo mechanical pulp 0 2.0 – 3.0
Table 30: Heat and power consumption in paper-making by product
Power consumption (net) in MWh/ADt
Explanatory notes: (-) indicates surplus
The units can be converted from MWh to GJ according to 1 MWh = 3.6 GJ and 1 GJ = 0.277 MWh
Data from [J. Pöyry, 1998], [SEPA Report 4712-4, 1997], [Finnish BAT Report, 1997]
1) The net process heat consumption depends mainly on the type of refining and the degree of heat recovery
2) The values can only be reached if heat recovery, paper machine press section and the use of electricity are all implemented and operated in an ideal way. In
existing processes this is rarely the case.
Table 31 gives benchmarks for the energy consumption for different
production steps for paper mills.
Department Process heat [MJ/t] Electric power [kWh/t]
Wood handling 150 50
Refining 0 21101)
Washing and screening 0 50
Bleaching 0 75
Bleach chemical preparation 0 5
Bleached stock screening 0 35
Power boiler 0 25
Total pulp mill 150 2350
Stock preparation 0 235
Paper machine 5300 1) 2) 350
Total paper mill 5300 585
Effluent treatment 0 39
Total per tonne of paper 5450 2974
Table 31: Energy consumption for different production steps for paper mills
Notes:
1) A Finnish integrated TMP mill higher electricity consumption in the range of 2400 kWh/t was reported for the refining stage (including reject refining) and a
lower value of 4800 MJ/t process heat consumption for the paper machine respectively [Finnish comments].
2) A Swedish newsprint mill reports a heat demand of about 4 GJ/t for drying paper, a need that will be reduced by about 10% with a future shoe-press installation.
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