The study was done as a KCL research project and it describes the development of kraft pulping technology in Finnish kraft pulp mills. Both kraft production technology and process energy balance are included. Data was collected directly from the mills and the results will be presented as an average of this data. The study covers a wide range of environmental and energy parameters. The main findings of the environmental changes and their interaction with technology development will be presented. The focus is on water emissions, air emissions and energy balance. Solid waste is excluded from the study. The results showed that both supporting technology and core technology are equally important in reducing the environmental load from kraft pulp mills. The most important supporting technologies were the proper function of the active sludge treatment plant and different purification techniques for air emissions. Dry debarking, oxygen delignification, improved high dry substance of black liquor and lime mud drying are examples of the most important core technologies. Waste water volume has less significance for water emissions than expected. Energy balance is highly dependent on the 'age' and total concept of the mill and is not specifically affected by single technology developments.
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