Round wood storage
ZPR uses round wood (softwood, mainly spruce and pine) from the surrounding forests and chips from sawmills. From the round wood storage the wood logs are transported over a conveyor bridge to the wood chipping department.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/1A.jpg
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/1B.jpg
Wood chipping
Here the log wood is mechanically debarked, crushed into wood chips and then stored on the chip pile.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/2A.jpg
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/2B.jpg
Chip storage
On the chip pile the chips from round wood and the saw mill chips are separately stored. In the line with production conditions the ratio of the wood chips (saw mill : log timber) is specified depending on the respective pulp´s requirements.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/3A.jpg
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/3B.jpg
Digestion
Before the actual cooking process the wood chips are dampened and impregnated. Afterwards, the pulp fibers are dissolved in an alkaline solution under pressure and heat. The process ends after about 4 hours. The extracted pulp is separated from non-decomposed knots and splinters.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/4A.jpg
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/4B.jpg
Bleaching plant
Depending on the customer´s requirements, there follows the bleaching in an elementary chlorine free or totally chlorine free bleaching sequence. Elementary chlorine free bleaches with hydrogen peroxide, oxygen and chlorine dioxide. Totally chlorine free bleaches with hydrogen peroxide, oxygen and ozone.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/5A.jpg
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/5B.jpg
Drying
The aqueous pulp suspension is first mechanically drained on a mesh screen and then passed through presses. It is thermally dried to final dryness of approx. 90 % in a drying chamber.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/6A.jpg
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/6B.jpg
Packaging and shipping
In the baling section the pulp coming off the line is cut to size and carefully stacked to form 250 kg bales. 8 bales are then wired together to make up one unit ready for shipping. More than 80 % of the pulp is shipped by train.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/7A.jpg
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/7B.jpg
Evaporation
The broken down, dissolved wood substances from the cooking process, the so-called “black liquor” is thickened to a dryness of approx. 75 %. The result is the “thick liquor”.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/8.jpg
Recovery boiler
The thick liquor is burned in the recovery boiler. Heat is generated, which is used to produce steam. The chemicals are reduced and settle on the floor of the boiler as a smelt and flow into the dissolving tank. By adding water the reduced chemicals are dissolved into the white liquor. The resulting green liquor is pumped into the causticizer.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/9.JPG
Causticizer
Anhydrous lime (burnt lime) is added to the green liquor from which white liquor is then produced. After filtration, this white liquor is added back into the pulp production process. The remaining carbonate sludge is washed and dried.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/10.jpg
Lime kiln
The dried carbonate sludge is burned to form calcium oxide (burnt lime). The burnt lime is also fed back into the chemicals circle.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/11.jpg
Energy recovery
The steam produced in the recovery boiler and in the recovery boiler and in the bark incinerator is first used in a steam turbine to generate electricity. It is then used in production as process stream. The turbine generates between 50 and 57 MW of electricity. The plant has an average requirement of 30 MW, the rest is fed into the public electricity grid.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/12.jpg
Effluent treatment plant
Company-owned wastewater treatment plant: We have almost eliminated biologically degradable substances, with wastewater values clearly below the prescribed limits and among the best performances internationally.
fileadmin/user_upload/zpr.de/Images/Produktionsprozess/13.jpg
×
![]()
![]()